Miscellaneous - UWorld Flashcards
0
Q
Elastic resistance in the lungs increases WOB with regards to tidal volume so you increase RR to optimize whereas airflow resistance (COPD, emphysema, alpha-1 anti-trypsin, anxiety) is characterized by needed to take few, deep breaths - meaning reduce RR.
A
Repeat
1
Q
Attributable risk percent
A
ARP(exposed) = 100 x [(Risk exposed - risk unexposed)/(risk exposed)]
2
Q
How is filtration fraction calculated?
A
FF = GFR/RPF. Normally 0.15-0.2 because GFR is 125 and RPF is 600-700.
3
Q
What is the mechanism of Fragile X?
A
The additional CGG repeats (that present as Fragile X when they are over 200) cause methylation of the FMR (fragile X mental retardation gene) on the X chromosome that renders the gene inactive. This gene is usually required for proper neural development.
Presentation: Mental retardation, dysmorphic face, large testes.
4
Q
If the superior thyroid artery is ligated, what nerve and associated muscle and sensory supply is likely to be ligated with it?
A
The superior thyroid artery runs with the superior laryngeal nerve (vagus origin) which ONLY supplies cricothyroid muscle (external branch of the superior laryngeal nerve) and supplies ALL sensory innervation above the vocal chords (internal branch of the superior laryngeal nerve).
5
Q
What are the cells that following an ischemic injury to the brain could be expected to be filled with lipid contents?
A
Microglia - these cells appear from 3-5 days after ischemic injury in the brain (CNS) onward and phagocytize myelin, dead neurons (red neurons - occur 48 hrs in, sign of irreversible damage), and debris. The first cells to appear in the setting of ischemic injury in the brain are neutrophils (recall these are NOT phagocytes).
Note, astrocyes form glial scar around cystic space about 2 weeks after injury.
6
Q
What E. Coli virulence factor is responsible for its infectivity in UTIs?
A
fimbria - pili.
E.Coli’s capsule - neonatal meningitis - prevents phagocytosis
Lipopolysaccharide - bacteremia and septic shock - causes macrophage activation.
7
Q
What is the significance of increased acetylcholinesterase in amniotic fluid?
A
Suggests neural tube defects (failure of fusion of the neuropores). Synonymous with increased AFP.
8
Q
Rapidly developing cutaneous flushing, tachypnea, headache, and tachycardia are concerning for…
What is treatment?
A
Cyanite poisoning which can cause quick death by binding to the cytochrome a-a3 complex (critical for electron transport in oxidative phosphorylation).
Treatment: Nitrites or sodium thiosulfate. These nitrites are used to induce methemoglobinemia and convert iron to Fe3+ which more strongly binds cyanide and thereby spares the mitochondrial enzymes from cyanide’s toxic effects.
9
Q
Hepatitis D relies on Hepatitis B for…. To be effective
A
Viral coat (HBSAg).
10
Q
Neisseria meningitidis and Neisseria gonorrhea have an effective mechanism against an immunoglobulin to assist with mucosal penetration.
A
IgA protease that cleaves IgA hinge region. Normally IgA binds to pili and fimbria of organisms to prevent mucosal penetration.
11
Q
Leptin inhibits production of ________ and increases production of ____
A
Inhibits neuropeptide Y. Increases alpha-MSH. Leptin is produced by adipocytes and acts on the Arcuate nucleus of the hypothalamus.
12
Q
What does the ventral pancreatic bud give rise to?
A
It gives rise to the uncinate process, inferior/posterior portions of the pancreatic head, and the MAIN pancreatic duct.
In pancreas divisum where there is failure of fusion of the two buds, the accessory duct drains dorsal bud derived structures which are the majority of pancreas. The fusion should occur around week 8. (Foregut)
13
Q
What cancer is associated with Auer rods?
What is the chromosomal abnormality associated with it?
A
Acute myeloblastic leukemia (M3 variant) specifically acute promyelocytic leukemia.
Chromosome t(15;17). The M2 variant which also has Auer rods is t(8;21).
14
Q
A study that measures exposure and outcome AT ONE TIME is a…
A
Cross-sectional study.
15
Q
Where are the cell bodies of cholinergic neurons in the brain?
In what common disease are these cell bodies affected?
A
Nucleus Basalis of Meynert
Alzheimer’s disease
16
Q
Where in the brain does the progressive neurological disease associated with Wilson’s disease cause copper deposition?
A
Putamen
17
Q
In what type of muscle is myosin light chain kinase found?
A
Smooth muscle.
18
Q
Red neurons means at least 48 hrs after the injury. Do not forget that after the Nissl substance disappears the nuclei of these neurons becomes DEEPLY basophilic. These are NOT neutrophils. You are still 48 hrs out of the injury. Look for Mickey Mouse ears for neutrophils.
A
Repeat
19
Q
How far out of an ischemic injury does liquefactive necrosis and reactive gliosis begin to occur?
A
1-2 weeks.
20
Q
What enzyme is deficient in Tay-Sachs?
What metabolite accumulates?
A
Beta-hexoaminidase A is missing.
GM2 ganglioside is the metabolite that accumulates.
There is NO hepatosplenomegaly in Tay-Sachs.
21
Q
If a patient has an advance directive, it is the physician who should make the decision and they should ALWAYS follow it.
A
Repeat.
22
Q
What is metacholine’s effect on airways
A
It is a CHOLINERGIC agonist. It causes bronchoconstriction (>20% is asthma) and increased secretions.
23
Q
What does folate deficiency do?
What agent if added can mitigate its effects?
A
Folate deficiency limits DNA synthesis and promotes megaloblastosis and increases erythroid apoptosis.
To mitigate its effects, you can supplement with thymidine. (dTMP).
24
Rheumatic heart disease tends to present as ________ murmur when patients are younger and ______ murmur when they are middle aged.
Mitral regurgitation when patients are younger.
Mitral stenosis when they are middle aged.
When they are older, you can see a mixed presentation.
25
What are the proteins associated with the following HIV genes?
gag -
Env -
Which proteins are REQUIRED for replication of HIV?
gag - nucleocapsid - p24, p7
Envelope - gp 120, gp 41
Required for viral replication? Tat, rev
26
What does crescent formation in the glomerulus usually indicate? Which do the crescents consist of?
Crescents usually indicate rapidly progressing glomerulonephritis (weeks to months).
The crescents include abundant fibrin, glomerular parietal cells, monocytes, macrophages. These crescents disrupt renal function.
27
Around when should the Vitelline duct disappear in embryonal development?
7th week
28
How can methylmalonic acid acidemia result?
It can result from failure of isomerization of methylmalonic acid CoA to succinyl CoA which then enters the citric acid cycle (TCA).
29
Joint pain and pruiritic rash shortly after starting a monoclonal antibody is concerning for_______
What is the pathophysiology?
Serum sickness
Pathophysiology: Type III hypersensitivity reaction (immune complex) with immune complex deposition which involves neutrophil and complement activitation. Expect to see low complement levels (C3, C4) and neutropenia (all the neutrophils are being attracted to site of injury). Small vessel vasculitis with fibrinoid necrosis is also common.
30
What is the role of Sertoli cells?
They secrete inhibin B, promote spermatogenesis and release Mullerian inhibiting hormone.
31
If alveolar oxygen and tracheal oxygen equilibrate AT REST, what kind of defect do you have? This defect is true especially if pCO2 in the alveolus is LOWER than expected.
Were oxygen to equilibrate during exercise or in a disease state AND pCO2 levels in the alveolus were normal, the defect would be?
Perfusion defect. Normally, alveolar oxygen should be 104mmHg while tracheal oxygen should be 140mmHg.
If pCO2 levels were normal and oxygen equilibrate you would have a diffusion exchange defect as is the case in emphysema, pulmonary fibrosis, or high exercise state.
32
If someone notices diplopia especially when walking down stairs or reading the newspaper they have what nerve injury?
Trochlear nerve - vertical diplopia.
33
Where are Peyer's patches located? What kind of tissue are they?
Ileum. Lymphoid tissue.
34
Primary amenorrhea is defined as absence of menses by age 15 if you have secondary sex characteristics or absence of amenorrhea by age 13 if NO secondary sex characteristics are present.
Repeat
35
What process do endometrial cells undergo in response to withdrawing progesterone?
Apoptosis
36
In a bicornuate uterus, which ducts fail to fuse?
Paramesonephric ducts.
37
What is the function of smooth ER?
Smooth ER contains enzymes for steroid and phospholipid biosynthesis. Thus, well-developed smooth ER present in the adrenals, gonads, and liver.
38
What is the significance of S4?
It is the sound of blood hitting a stiff left ventricle.
39
What are the ST DEV benchmarks
1 SD is 68%
2 SD is 95%
3 SD is 99.7%
40
Between diet control and smoking cessation which is best to reduce mortality?
Smoking cessation.
41
When is pulmonary vascular resistance lowest?
PVR is lowest at functional residual capacity which is the volume left after regular exhalation.
42
What are the stop codons? What do they encode?
UAA, UAG, and UGA. They code for releasing factors.
43
What is the start codon?
AUG - encodes methionine.
44
What reaction does glucose 6 phosphate dehydrogenase catalyze?
What is its inheritance pattern?
Glucose 6 phosphate dehydrogenase catalyzes the conversion of glucose-6-phosphate to 6-phosphogluconate. One NADPH (reducing equivalent) is formed in this irreversible reaction.
It is inherited in an X-linked pattern.
45
If a mom experiences virilization during pregnancy and her baby is born with ambiguous genitalia and increased levels of testosterone and androstenedione, what deficiency is occurring? Where is this enzyme active during pregnancy?
Aromatics deficiency. It is active in the placenta.
46
If a baby is born with ambiguous genitalia (if female) and has hypotension and salt-wasting, what hormone is decreased?
Aldosterone. This is 21 hydroxylase deficiency. Also low levels of cortisol. Due to the deficiency, more things are routed to androgens.
47
If you are born with ambiguous genitalia (if male) and increased mineralocorticoid activity (hypertension and salt retention), you have
17 alpha hydroxylase activity.
48
How do you calculate number needed to treat if there is a control group and a treatment group
NTT = 1/(Control Rate - Treatment Rate).
49
What immune complexes are deposited on the epithelial side of the GBM in post-strep GN?
Where in the nephron structure are these deposits found?
What are other common laboratory findings?
IgG, IgM, C3
Location: mesangium and basement membrane. "starry sky" appearance.
Common findings: elevated anti-streptolysin O, elevated DNA-ase B, decreased C3, presence of cryoglobulins
50
What common signals use the JAK/STAT pathway?
Growth hormone, prolactin, cytokines, colony-stimulating factors. For these signals, the receptor is ASSOCIATED with a tyrosine kinase pathway. The receptor itself is not a tyrosine kinase.
This pathway is NOT used by INSULIN.
51
What structures does the metanephric mesoderm give rise to?
Glomeruli, Bowman's space, PCT, loop of Henle, DCT.
NOT the collecting duct.
52
What happens to C-peptide after it is cleaved off pro-insulin in the Golgi apparatus (making insulin and C-peptide)
c-peptide is packaged into islet cell secretory granules along with insulin. They are then released in equal concentration into the extracellular space.
53
If a patient with history of recurrent infection (GI or sinopulmonary) has an Anaphylactoid reaction to a blood transfusion, he/she has....
IgA deficiency. These patients often have IgG antibodies directed against IgA which is transfused along with blood.
54
What vitamin is an essential co-factor in transamination reactions where an amino acid is being generated?
Pyridoxine (B6)
55
What enzymes require thiamine (Vitamin B1) as a co-factor?
Pyruvate dehydrogenase, alpha-keto glutarate dehydrogenase and transketolase.
56
Patients with cystinuria who may present with cystine hexagonal stones which are pathognomonic will also have problems transporting..
Lysine, arginine, ornithine.
57
What disease (of young people) that occurs 2-3 days after a flu-like illness is associated with mesangial deposits?
IgA nephropathy. Patients have recurrent bouts of painless hematuria. In half of patients can progress to chronic renal failure.
58
What is the embryologic origin of the following congenital heart defects: Tetralogy of Fallot, truncus arteriosus, and transposition of great arteries?
Failure of septations between the aorta and pulmonary artery due to abnormal migration of NEURAL crest cells through the primitive truncus arteriosus and bulbus cordis.
59
What is the term for trinucleotide repeats expanding with paternal transmission so that subsequent generations have earlier onset as is the case with Huntington's Dusease?
Anticipation.
60
What portion of an mRNA is NOT transcribed from a DNA template?
The portion following the AAUAAA on the 3 prime end of an mRNA tarnscript was not TRANSCRIBED from a DNA template as it represents the poly A tail. The poly A tail is a POST-TRANSCRIPTIONAL modification that protects the mRNA transcript from degradation.
61
What is the impact of disrupting t-tubules?
Disrupting the coordinated contraction of myofibrils. I.e. Getting uncoordinated myofibrils contractions because the t-tubules are invaginations of the sarcolemma (plasma membrane) that extend into each muscle fiber.
62
Extra medullary hematopoiesis, anemia, jaundice, generalized edema, uncleared erythrocytes in a newborn are concerning for...
Hemolytic disease of the newborn (erythroblastosis fetalis) which occurs due to maternal sensitization to a prior pregnancy with an RhD+ve baby. Maternal IgG antibodies cross the placenta.
63
Besides the deltoid, what other muscle does the axillary nerve innervate? What is the most common way the axillary nerve is injured?
Anterior shoulder dislocation due to forced external rotation and abduction.
Other muscle: Teres minor.
64
What substance secreted by inflammatory macrophages in artherosclerotic plaque compromises the integrity of the plaque?
Metalloproteinases which degrade collagen.
65
Membranoproliferative glomerulonephritis associated with ____ virus and ____ complement.
Hepatitis C virus
C1q complement.
66
At what stages of meiosis are primary oocytes arrested? What promotes their development? Secondary oocytes are ovulated at what arrested stage?
Primary oocytes at birth are in prophase of meiosis I. Ovarian cycle hormones help them complete their development. Secondary oocytes are then ovulated in metaphase of meiosis II.
67
Women who have just delivered babies with neural tube defects are asked about acetaminophen use in pregnancy. Women who delivered healthy babies are also asked about acetaminophen use in pregnancy. What measure of association are you likely to report?
Odds ratio (the example is of a case control study. You are looking for the odds of exposure in ALREADY diseased people as opposed to following them over time).
68
With what autosomal dominant disease are bilateral renal angiomyolipomas (fat, muscle, blood vessels) seen?
Tuberous sclerosis.
69
What is the policy on parental notification or consent for elective termination?
Two-thirds of states require parental consent.
70
What phases stimulate gastric acid secretion? What phase(s) inhibit it?
The cephalic phase (acetylcholine and vagal) and gastric phase (promoted by gastrin secretion which stimulates histamine which then stimulates acid) promote gastric acid secretion. The gastric phase is stimulated by the physical and chemical presence of food. Pls, note that when protein rich food enters the duodenum, the intestinal PHASE plays a minimal role in also stimulating gastric acid secretion.
The intestinal INFLUENCES inhibits it. These include peptide YY released by the ileum and colon that inhibits the ECL cells release of histamine. Also, somatostatin and prostaglandins similarly are intestinal influences that inhibit gastric acid secretion.
71
In what location in the GI tract is an ulcer LEAST likely to be malignant?
Duodenum. These ulcers are usually due to H.Pylori or NSAIDs.
Most common PEPTIC ulcer locations: Proximal duodenum, antral stomach, and gastro-esophageal junction
72
What type of CD4 Tcells help macrophages in the clearance of TB?
Th1
73
What drugs are most likely to cause drug-induced lupus?
SHIPP-E. Sulfa drugs, hydralazine, INH, Procainamide, Phenytoin, Etanercept.
74
Which ducts are affected in primary biliary cirrhosis and what immunologic marker is usually associated?
Intrahepatic. Anti-mitochondrial antibodies.
75
When a study's unit of analysis is populations and NOT individuals, what kind of study is it?
Ecological study.
76
What structure do the common cardinal veins drain into? What do they develop into?
Develop into SVC - superior vena cava and other veins. Drained embryologically into the sinus venosus.
77
What does the delta-F508 mutation result in terms of the CFTR?
It result in a problem with post-translational processing of CFTR that directs the protein to the proteasome so that it is completely absent from the apical surface of the cell.
78
How does the required immune cell for processing Candida change depending on the nature of the infection (I.e. Local vs systemic)? Systemic infection is considered synonymous with hematogenous spread.
For local infections (as is the case in HIV), T-cells are required but for systemic infection, neutrophils are required. Thus neutropenic patients tend to get systemic infection while HIV patients tend to get local infection.
79
What pediatric cardiac abnormality increases in sound with a handrip (an exercise that increases afterload)
VSD
80
What cells in the stomach secrete intrinsic factor and where are they located?
Parietal cells secrete HCl and intrinsic factor and they are located in the glandular layer. This is the cell layer affected in pernicious anemia leading to chronic Atrophic gastritis.
81
What do the chief cells in the stomach secrete?
Pepsinogen and are in the deeper glandular layer.
82
How does Ca2+ dramatically increase energy consumption in contracting muscles?
Ca2+ mediates the increased activity of myophosphorylase by allosterically activating phosphoryl kinase which then activates (phosphorylates) muscle phosphorylase.
83
When is chi-squared appropriate to analyze a test?
It is appropriate to analyze a test when your variables are recorded in a non-numerical way like the number of people with the variable as high or low. For z or t tests, you need variables that are recorded in a detailed numerical manner so you can calculate means (averages) for each variable.
84
What kind of effect does cortisol have on the normal effect of catecholamines?
Permissive - this means that on its own, cortisol has NO effect but when administered along with catecholamines, it increases their natural effect.
Other effect concepts:
Additive - if the combined effect of the two drugs is equal to the sum of each of their actions when used independently.
Synergistic - if the combined effect of the two drugs supersedes or is more than each of their individual effects added together.
85
What does tachyphylaxis refer to?
It refers to decreased effect to a drug with repeated exposure to it.
86
An infant with bilateral cleft lip, microcephaly, and microphthlamos, with an omphalocele is most concerning for...
Trisomy 13! Patau syndrome. MUST know. Non disjunction usually occurs in meiosis I.
87
Edwards syndrome, Trisomy 18, is associated with clenched hands, prominent occiput, low set malformed ears, small chin, small mouth.
Repeat.
88
What disease does primary biliary cirrhosis have findings similar to?
PBC has findings similar to graft vs hist including: granulomatous bile duct destruction and heavy lymphocyte-predominant portal tract infiltrate.
89
Fever, oral ulcers, and cervical lymphadenopathy in a patient aged 5 years is most concerning for...
Primary infection with HSV.
90
How does carbon dioxide exert its effect on Hemoglobin?
It competitively inhibits it --- meaning it competitively binds to heme (in terms of oxygen binding).
91
A dispropionate loss of a certain group to follow-up in a study is a form of what type of bias?
Selection bias -- specifically attrition bias.
92
What is lead time bias?
Lead time bias occurs when a screening test diagnoses a disease earlier than it would have otherwise been detected so that the time from diagnosis to death appears to be increasing even when there is no true change in survival.
93
When two viruses that independently would not have infected a cell create cytopathic effects when introduced together, what phenomenon has occured?
What type of viruses do these usually have to be?
Genome recombination has occured.
Occurs through crossing over of two Double stranded DNA molecules.
94
When two or more segmented viruses infect the same cell and mix their genetic informatics what is this called?
Reassortment
95
Where in the nephron is the most dilute concentration (~100mOsm) found?
Thick ascending loop of Henle and distal convoluted tubule, but especially DCT. DCT is impermeable to water.
96
Where does angiotensin II normally affect the kidney
EFFERENT arteriole - vasoconstricts the EFFERENT arteriole to increase GFR.
97
What are the most common metastases to the brain?
Lung cancer, renal cancer, melanoma.
98
How does nitroprusside work in the setting of heart failure?
Nitroprusside is an equal venous and arterial vasodilator. It REDUCES BOTH afterload and preload allowing similar cardiac output to be obtained at a lower left ventricular end diastolic PRESSURE. As a result the pressure-volume loop on nitroprusside is reduced in both directions. Shifted down and left but the cardiac contractility curve stays the same. You are just further down on the same curve. This means STROKE VOLUME is MAINTAINED.
99
When you match controls to your study population, you are correcting for what type of bias?
Confounding.
100
What causes cleft lip?
Failure of the maxillary prominences to properly fuse with the intermaxillary segment. The intermaxillary segment becomes the philtrum.
101
What causes cleft palate?
When the palatine shelves of the maxillary prominence fail to fuse with one another or with the primary plate.
102
When there is improper fusion of the maxillary prominence with the medial nasal prominence, what is the result?
Cleft lip
103
What immunologic deficiency predisposes to recurrent infections with Neisseria?
Failure of MAC complex C5b-C9.
104
What kind of protein is Ras which is involved in the RAS-MAP kinase pathway where a growth factor ligand binds to a tyrosine kinase that auto phosphorylates, interacts with SOS protein which then activates Ras.
RAS is a G-protein. When it is bound to GDP it is inactive. At the end of the cascade, MAP kinase alters gene transcription when it enters the nucleus.
105
Be careful when calculating the likelihood of a child acquiring autosomal recessive disease based on frequencies of allele in parent populations. Remember to multiply the frequency of each parent being a carrier by 1/2 for autosomal recessive disease because each parent has a 1 in 2 chance of passing the carrier allele to the child.
Repeat
106
What is the order of neutrophil movement?
Margination - vascular leakage in the microvasculature leads to hemoconcentration and decreased wall shear stress.
Rolling - neutrophils bind weakly to selectins
Activation - slow rolling allows neutrophils to sample chemokines being released which causes them to upregulate certain molecules (integrins).
Tight adhesion - neutrophils become firmly attached by CD 18 beta 2 integrins (Mac-1, LFA-1) binding ICAM on endothelial cells.
Transmigration - neutrophils then leave the vasculature by binding PECAM-1 molecules with their integrins. These PECAM molecules are at the peripheral intercellular junctions of endothelial cells.
107
Where is stratified squamous epithelium found?
Stratified squamous epithelium is ONLY found on the true vocal chords (vocal folds), Oropharynx, laryngopharynx, anterior epiglottis, upper half of posterior epiglottis.
All the other tissue in the respiratory tract is pseudostratified, columnar, mucus-secreting epithelium.
108
What co-factors does alpha keto acid dehydrogenase need?
| What two other similar enzymes require the same co-factors?
Tender Loving Care For Nancy - Thiamine, Lipoate, Coenzyme A, FAD, NAD.
Pyruvate dehydrogenase, alpha keto-glutamate dehydrogenase.
109
What is often seen with imperforate anus?
Urinary tract abnormalities.
110
What kind of junctions connect osteocytes in different lacuna?
Gap junctions
111
What directly dictates OSTEOCYTE activity? What indirectly?
Directly- plasma calcium concentration. Indirectly - PTH, calcitonin
In the setting of mechanical stresses, osteocytes can send signals and regulate the activity of surface osteoblasts I.e. Help regulate bone remodeling.
112
What are the less common genetic abnormalities that can lead to Down syndrome?
Unbalanced Robertsonian translocation - an extra arm of chromosome 21 is attached to another chromosome.
Mosaicism - patients have 2 lines - one with normal number of chromosomes and one with Trisomy 21.
113
What is the embryologic origin of the anterior pituitary? Inner ear?
Pineal gland?
Middle ear?
Anterior pituitary - Rathke's pouch - Surface ectoderm. Inner ear sensory organs has similar origin.
Pineal gland - neural tube (ectoderm)
Middle ear - endoderm
Look to Feb 25 test 1 Q2 for more info.
114
What structure does the notochord become in the adult?
Nucleus pulposus.
115
What does Nissl substance in neurons correspond to?
Rough endoplasmic reticulum.
116
What type of polymer are microvilli on intestinal cells made of?
ACTIN!!!!
117
A patient with dysarthria and contralateral ataxic hemiparesis is concerning for infarction of the ... Especially if facial weakness occurs in addition to hemiparesis.
Anterior portion of the medial pons - this is around the origin of the Trigeminal nerve. The middle cerebellar peduncles are also a great landmark for this region.
118
What drug works by competitive inhibition of iodide transport in the thyroid?
Potassium perchlorate. Pertechnetate ions also work through a similar pathway through the sodium-iodide SYMPORTER. This is used in hyperthyroidism
119
How do methimazole and PTU work?
Methimazole and PTU exert their action by blocking THYROID PEROXIDASE which converts Iodide TO IODINE. This class of drugs is called anti-thyroid thionamides.
120
What is important to remember about the lab values in polycythemia Vera?
In PV, ALL the cell lines are elevated.
121
What is the main defense against Giardia? How/where does Giardia exert its effect?
Diagnostic work-up:
IgA is the main defense against Giardia as Giardia causes injury to the mucosa in the duodenum and jejunum by ADHERING to the brush border and releasing molecules that induce mucosal inflammatory response. IgA interferes with adherence. Thus, if someone is IgA deficient for any reason, they are more likely to get Giardia.
Work up for diagnosis: Stool ova and parasites.
122
What is the central issue in CVID?
Decrease in plasma cells causes decrease in immunoglobulins. It is a defect in B-cell differentiation.
123
What is the pathogenesis of the less common, brown pigment stone
They arise typically secondary to infection of the biliary tract that results in the release of Beta-glucoronidase from injured hepatocytes and bacteria. The presence of beta-glucoronidase contributes to hydrolysis of bile glucoronides that results in INCREASE in amount of UNCONJUNGATED BILIRUBIN in BILE.
124
What values of the pulmonary function test does COPD increase? Decrease?
COPD decreases elastic recoil and FEV1 and/or FVC.
It INCREASES residual volume, functional residual capacity and total lung capacity.
125
Where is Anserine bursal located?
It is located along the medial aspect of the knee and is usually overused by athletes or chronic trauma in people with large body habitus.
126
What does prolonged kneeling put someone at risk for that develops as pain, erythema, swelling, and inability to kneel on the affected side.
Pre-patellar bursa.
127
If a patient presents with hypoglycemia and high NADH in liver what does this suggest?
An alternate fuel other than glucose is being used. E.g. Alcohol which increases the NADH/NAD ratio and inhibits gluconeogenesis.
This (high NADH) promotes the conversion of Pyruvate to lactate and the conversion of oxalateacetate to malate. Pyruvate and oxaloacetate are both required for gluconeogenesis.
128
What is the most helpful sign in distinguishing common peroneal nerve injury from superficial peroneal nerve injury?
In common peroneal nerve injury, loss of dorsiflexion, I.e. Foot drop is present because the deep peroneal nerve innervates the dorsiflexors of the foot.
129
In what pharyngeal pouch does the thymus develop? What is the only other anatomical structure that develops in the same pouch?
Pharyngeal pouch 3. INFERIOR parathyroid glands.
See 2/25 Test 3, Q2 for other pharyngeal pouch origins.
130
What gives rise to the thyroid gland embryologically?
The floor of the FOREGUT!!! The thyroid migrates downward from the mouth but remains connected by the thyroglossal duct.
131
What is the main substance in the cytoplasmic granules of eosinophils that is though to target helminths?
What is the interleukin signal for IgE production?
Major basic protein
IL-4
132
Why is duodenal enteropeptidase important?
It activates trypsinogen to trypsin.
Trypsin is essential for degrading complex peptides into dipeptides and amino acids. It is also important for activating other peptidases like carboxypeptidase, elastase, and chemotrypsin.
133
What is the most common cause of FETAL hydronephrosis?
Failure of recanalization at the ureteropelvic junction, the junction between the kidney and the ureter.
134
What is the appropriate control group in a case-control study.
Individuals without the disease, regardless of their exposure status.
135
Blood flow per minute must be equivalent AT ALL times between the pulmonary and systemic circuits
Repeat
136
What does absence of surfactant, neonatal resp distress, show up as on CXR?
Patchy alveolar atelectasis.
137
In the eat, what structure is close to place where you hear high frequency sound? Low frequency?
High frequency - basilar membrane. Low frequency - helicotrema is large and flexible for low frequency.
138
Bone pain, Salt and pepper skull, and sub-periosteal erosions affecting the phalanges of the hand, and brown tumor cysts are suggestive of
Primary hyperparathyroidism. Osteitis fibrosa cystica.
139
What does IL-12 do?
It stimulates naive T-cells to become T-helper 1 cells. Patients who are IL-12 receptor deficient on their T-cells are susceptible to MYCOBACTERIAL infections due to their inability to mount string granulomatous response. Treat with IFN-gamma.
140
Is LPS secreted by bacteria?
NOOOO. Gram-negative bacteria can release LPS during lysis or during division but they do not secrete it. Lipid A is the toxic so pinene of LPS. It causes activation of macrophages leading to widespread release of IL-1 and TNF-alpha which are associated with symptoms of shock.
141
Remember to be careful when trying to distinguish between bipolar disease with psychotics features and schizoaffective disorder.
In schizoaffective disorder, psychosis MUST occur in the absence of major mood episodes but mood symptoms have to be present for most of the illness. There must be at least 2 weeks of psychosis in the absence of mood symptoms.
Whereas in major depressive or bipolar disorder with psychotic features, psychosis has to always occur in the setting of mood symptoms.
142
In DNA base excision repair, which is used to correct defects in single bases, what enzyme initiates the process? What are the next steps?
Glucosylase removes the defective base first. Then, the corresponding sugar-phosphate bond is cleaved and removed by endonuclease.
Lyase follows.
Then DNA polymerase. Then ligase.
143
What type of collagen is found in scar tissue? What other types of collagen is it similar to? In what disease is there a defect in this type of collagen.
What is the inheritance pattern of this disease?
Scar tissue contains Type 1 collagen. It is also present in tendons, bone, dentin, ligaments.
Type 1 collagen is defective in osteogenesis imperfecta. Autosomal dominant.
144
A patient who does not agree with his doctor and then begins coming to subsequent appointments late or canceling them is exhibiting ehat defense mechanism?
Passive aggressiveness. It is carrying out hostile feelings in a non-conformational manner.
145
A pro-thrombotic state in a young (under 50) Caucasian female which has a normal PTT and is resistant to activated Protein C is suggestive of ...
Factor V Leiden disease which accounts for Factor Va resistance to being inactivated by (activated) Protein C.
146
What is the pathophysiology of Toxic Shock?
Superantigens activate a large number of T-helper cells which go on to release IL-2.
These T-cells activate macrophages which release IL-1 and TNF-alpha.
147
What is path of Cloristidium tetani in order to cause an infection?
It goes from the wound to motor neurons (retrograde transport) to the spinal cord and prevents inhibitory neurons firing. tetanus presents primarily with rigidity of the face, neck, and trunk.
148
What nerve is injured in Trendenlenberg?
Superior gluteal nerve! It innervates gluteus minimus and medius. Also innervates TFL ( tensor fascia lata).
149
What is clinical presentation is associated with inferior gluteal nerve injury?
Difficulty arising from a seated position (or climbing chairs). The. Inferior gluteal nerve innervates gluteus Maximus which is responsible for extension and external rotation of the thigh at the hip.
150
A child holding an injured arm in a fully extended and pronated position likely has what kind of injury?
Radial head subluxation at the elbow or annular ligament tear/displacement. This injury (nursemaid's elbow) usually occurs due to sudden traction of an outstretched and pronated arm.
151
D-xylose is what kind of carbohydrate -- monomer or polymer?
It is a monosaccharide. It DOES NOT require pancreatic enzymes so it is used to distinguish malabsorption due to pancreatic disease from GI absorption disease.
152
What is responsible for cleaving the di-sulfide rich terminal extensions of the pro-collagen molecule?
Extracellular transpeptidases. The cleaving by these peptidases allows the formation of troopcollagen which is less soluble and can then assemble into collagen fibrils.
The final crosslinking of these collagen fibrils is accomplished by Lysyl oxidase.
153
What is the treatment for Enterobius (pinworm) in the peri-anal area?
Albendazole
154
What is dietylcarbamazine used for?
Loa Loa and wucheria (lymphatic filariasis)
155
What is ivermectin used for?
Stronglyoides and Onchocerca
156
What is nifurtimox used for?
Chagas - trypanosome.
157
Amyloid deposition confined or a single organ is usually due to a protein specific to that organ. What are some common ones?
```
Cardiac atria: atrial natriuretic peptide
Pancreas: amylin (islet amyloid protein)
Thyroid gland: calcitonin
Cerebrum/cerebellum: beta-amyloid
Pituitary: prolactin
```
Note that immune globulin deposition causes primary SYSTEMIC amyloidosis not a local amyloid deposition.
158
What equation does 21 hydroxylase catalyze?
It catalyzes the conversion of progesterone to 11 deoxycorticosterone.
159
How do nitrates exert their effect?
They are converted to NO (endothelial derived relaxing factor) and increase cGMP, decrease intracellular calcium and result in myosin dephosporylation.
160
A pale retina and a cherry red macula are concerning for...
Central retinal artery occlusion. Another clue is that this results in permanent prolonged loss of vision.
161
Amaurosis fugax is a painless, TRANSIENT loss in vision. Usually does not last more than a few seconds.
Repeat.
162
A patient with orotic acid in her urine has a defect in ______ synthesis
PYRIMIDINE. They will present with hypo chromic megaloblastic anemia, neurologic abnormalities, growth retardation, and orotic acid in urine.
Supplements with uridine which will block the activity of carbamoyl phosphate synthetase II.
163
Muscle fibers with a blotchy red appearance on GOMORI TRI-CHROME stain are suggestive of what kind of disease?
Mitochondrial myopathies.
I.e. They have no likelihood of being passed from a father and 100% for being passed on by a mother.
164
When a person is standing upright, perfusion is greatest at the base of the lungs as is ventilation but perfusion is increased far greater than ventilation meaning that as you go from Apex to base, V/Q reduces dramatically.
Repeat
165
What drug can chelate calcium and promote nephrotoxic renal magnesium wasting leading to hypocalcemia and hypomagnesemia?
Foscarnet
166
How does Flutamide exert its effect in prostate cancer?
Flutamide is a non-steroid anti-androgen that competes with testosterone and DHT for testosterone receptors. If used as monotherapy, as a result of negative feedback it can result in gradual increase of serum testosterone so simultaneous GnRH inhibition with GnRH agonist.
Flutamide by itself can shrink the size both of the primary tumor and its metastases.
167
Where does CO2 increase in aerobic exercise?
CO2 content increases in mixed venous blood because exercise causes oxidative metabolism of glucose and fatty acids. There ARE no changes in arterial pH and blood gas due to homeostatic regulation.
168
How do your treat slow-growing cervicofacial Actinomyces infection that usually occurs in setting of oral or dental trauma?
Long course of penicillin treatment and debridement.
169
MAC of anesthetic corresponds to?
The dose (concentration) of anesthetic in alveoli at which 50% of patients were non-responsive to painful stimuli. MAC is inversely proportional to potency. The lower the MAC, the more potent the anesthetic.
170
What do enolase, chronogranin, and synaptophysin share in common?
They are neuroendocrine markers. Chronogranin for example, can be seen in small cell carcinoma of the lung.
171
What is vimentin?
Vimentin is an intermediate filament used to diagnose sarcomas.
172
What is tetrahydrobiopterin?
It is a cofactor for phenylalanine hydroxylase (PAH)
173
Where in the urea cycle is N-acetylglutamate needed?
It serves as a cofactor for carbamoyl phosphate I in the addition of CO2 to NH3.
N-acetylglutamate is formed by N-acetylglutamate synthetase from acetyl-CoA and glutamate.
174
What do Rb, p53, APC/Beta-catenin, and BRCA genes have in common?
They are all tumor suppressor genes. They need to be inactivated in cancer.
175
What drugs will increase levels of warfarin in the blood by inhibiting its metabolism?
Cimetidine, Bactrim, Amiodarone.
176
What drugs can lead to sub-therapeutic warfarin levels by speeding up the Cytochrome P-450 system?
Phenytoin, phenobarbital, and RIFAMPICIN/Rifampin.
177
Metabolism of 1g of protein or carbs gives you ___ cal.
Metabolism of 1g of fat gives you ___ cal.
1g of protein or carb is 4cal.
1g of fat is 9 cal.
178
When after ischemia does the myocardium stop contracting? When is the point of irreversibility?
Myocardial contractility stops contracting within 60 seconds of ischemia. Lactate begins building up immediately.
The point of irreversible damage even if blood flow is restored is 30 minutes.
179
What is the meningitis vaccine made of? How about the conjugate vaccines?
Meningitis vaccine is made of the polysaccharide capsule. The conjugate vaccines are attached to diphtheria toxoid protein.
Note the capsule in Neisseria meningitidis is what normally impairs phagocytosis.
180
In the renal proximal tubules, what is secreted?
What is absorbed?
Secreted:
Freely filtered and secreted:
creatinine (20% of the amount in the post-glomerular capillaries is secreted by PCT).
PAH (at low concentrations, up to 90% is secreted by PCT).
Not absorbed: inulin - though inulin is not secreted, it's relative concentration in PCT increases.
Freely filtered, Poorly absorbed: Urea.
Similar line for chloride. Far less so but similar line for potassium.
------- at about the same throughout the length of the PCT is SODIUM!
Decreasing concentration along PCT.
Bicarbonate - actively reabsorbed due to activity of carbonic anhydrase.
Glucose
Amino acids
181
What term refers to the amount of oxygen dissolved in the plasma?
What is oxygen saturation?
Partial pressure of oxygen in arterial blood. Carbon dioxide poisoning and methemoglobinemia (as a result of nitrites) do not change this.
----------------
Percent saturation is amount of oxygen per gram of hemoglobin. Should be unchanged in anemia and polycythemia. Should be decreased in carbon dioxide poisoning.
182
What interleukin is thought to downregulate the immune system along with TGF-beta?
IL-10
183
What does hyperventilation do?
It decreases the arterial partial CO2 tension.
184
Regardless of the topic of discussion, general medical or otherwise, a parent who is taking over the visit with an adolescent patient should be asked to step out.
Repeat
185
Fatigability, weight gain, and focal mounding of muscle on percussion (myoedema) and elevated CK are suggestive of... Myalgia and proximal muscle weakness are also present.
HYPOthyroid induced myopathy. This form of myopathy can precede other signs of hypothyroidism by several years.
The myoedema is cause by slow uptake of the Ca2+ by the sarcoplasmic reticulum.
186
In gluco-corticoid induced myopathy with progressive proximal muscle weakness and atrophy without pain, the CK is...
Normal!
187
In statin induced myopathy, patients experience proximal muscle weakness and pain within months of starting a statin and the creatinine kinase is...
ELEVATED!
188
What is the mechanism of intestinal atresia depending on its location???
Beyond/Distal to duodenum e.g. Involving the ileum spiraling around a vessel - it is due to VASCULAR OCCLUSION in utero. If the "Apple core lesion" with the ileum wrapping around and ileocolic vessel is seen, it usually means there was occlusion of the Superior mesenteric artery.
Duodenal atresia - due to failure of recanalization
189
What might explain vomiting in a 3 month old that involves pancreatic tissue encircling his duodenum.
Annular pancreas - abnormal migration of the ventral bud.
190
A young child with hypertension and mild Hypokalemia early in life is concerning for...
11 beta hydroxylase deficiency. They have high levels of deoxycorticosterone (weak mineralocorticoid) and androgens.
191
If you need a short-acting benzodiazepine that is good for insomnia due to its short-term effects use...
Triazolam or
| Alprazolam.
192
Streptococcus pneumoniae is optochin ________ (sensitive/resistant) and bile _______soluble/min soluble
Strep pneumonia is alpha hemolytic (green, incomplete hemolysis) optochin sensitive and bile soluble.
193
Trendenlenberg suggests injury to the CONTRALATERAL superior gluteal nerve which traverses on the...
SUPEROMEDIAL side of the buttock (again on the side CONTRALATERAL to the side that drops). If the right hip drops when the patient walks, it is a left superior gluteal nerve issue.
194
What two important metabolites does hyperammonemia deplete?
Alpha keto-glutarate AND GLUTAMATE. Don't be fooled, hyperammonemia makes glutamine. It does not deplete it. Hyperammonemia causes increased conversion of glutamATE to glutaMINE in the astrocytes.
Note that glutaMATE is the excitatory neurotransmitter.
195
Angiokeratomas (non-blanching between the umbilicus and the knees), acroparasthesias (burning or numbing sensation on awakening or following nerve compression), and hypohidrosis (sweating too little) in the setting of excess ceramide trihexose del is concerning for...
What is the end result of this disease?
fabry's disease.
Progressive Renal failure is the end result of Fabry's disease. The missing enzyme is alpha-galactosidase A.
196
Anosmia and Hypogonadism in a male suggest...
Kallmann syndrome, which results in absence of GnRH secretory neurons in the hypothalamus. They fail to migrate from olfactory placode.
197
Where are the nerves and blood vessels that supply the ovary?
Suspensory ligament.
Note, the ovarian ligament has NO blood supply.
198
Berkson bias is picking hospital patients.
Hawthorne effect is study participant changing their behavior once they know they are being studied.
Pygmalion effect is if a researcher's beliefs in the efficacy of treatment affect the outcome.
Repeat
199
What is the cardiac auscultation finding associated with atrial septal defects that can contribute to paradoxical embolism?
Fixed split S2. Does not change with respiration. Paradoxical embolism occurs when you have a cerebral event in the setting of DVT.
200
Circulating copper does so in the plasma as ceruloplasmin. Excess Copper is secreted into bile. Senescent ceruloplasmin has the same fate.
Repeat
201
Embryology
Aortic arches
What aortic arch gives rise to the common carotid and internal carotid?
What aortic arch gives rise to the subclavian?
What aortic arch gives rise to the true aortic arch?
3rd aortic arch associated with glossopharyngeal nerve gives rise to internal and common carotid arteries
4th aortic arch associated with superior laryngeal branch of the vagus nerve gives rise to the TRUE aortic arch and the subclavian arteries.
Note the 5th arch is obliterated in fetal development.
The 6th arch is associated with recurrent laryngeal nerve and pulmonary arteries/ductus arteriosus.
202
What does histone DE-acetylation do?
In what inherited, autosomal dominant, genetic disease is this thought to play a role?
What are the repeats in Huntington's?
Histone deacetylation allows the histones to interact MORE closely with the DNA causing reduced transcription of genes.
Hungtinton's disease (autosomal dominant)
Repeats are CAG repeats.
203
What is the primary nerve that innervates the dorsum of the foot with the exception of a little patch between big toe and second toe?
Superficial peroneal nerve.
204
How do you calculate renal clearance?
How do you go from this or calculation filtration fraction?
Clearance = (urine concentration x urine flow rate)/plasma concentration
You calculate filtration fraction by using the clearance of Creatinine or Inulin to calculate GFR and
you use the clearance of PAH to calculate renal plasma flow.
205
What is Starling's equation for calculating GFR?
GFR = Kf [(Pg - Pb) - (Oncotic pressure glomerulus - Oncotic pressure Bowman's)]
The P stands for hydrostatic pressure.
Kf is the filtration coefficient.
206
What is the core pathophysiology of Kartagener's syndrome?
Failure of DYNEIN arms to develop that connect the microtubules that form the cilia.
This results in recurrent respiratory infections. Also associated with DEXTROCARDIA and infertility in men and women.
207
If a test comes up with a different result each time it is used on the same sample, what is the issue?
What time of error is associated with this?
The test is not RELIABLE. This is due to random error.
208
When a test is not accurate, what does that mean?
What kind of error is associated with accuracy?
How is the accuracy of a test be evaluated?
It is not valid -- the trueness of the test's measurements are being called into question.
Accuracy (validity) -- associated with systematic error.
The accuracy of a test is evaluated by comparing it to the gold standard.
209
What is the genetic origin of a COMPLETE mole (46, XX or 46, XY)?
A COMPLETE mole is COMPLETELY of paternal origin. This results when sperm fertilizes an ovum that has lost its maternal chromosomes and the sperm genetic information is duplicated.
High malignant potential.
210
What is the genetic origin of a partial mole (69, XXX or 69, XXY)?
Fertilization of one ovum by 2 or more sperm.
Partial moles have LOW potential for malignancy.
211
In an emergency situation, if the patient is unable to consent, and the physician is able to in his/her reasonable judgement determine that the patient's family is who they say they are (I.e. No ID) and it serves in the patient's best interest, the physician may provide the family with general information regarding the patient's status.
Repeat
212
What is the effect of anterior cerebral artery occlusion?
CONTRALATERAL motor and sensory deficits of the lower extremities, behavioral changes, and urinary incontinence.
213
If a medical error has occured, the right thing to do is to: (pick one of the following): tell the patient or involve risk management?
TELL the patient. Forget risk management. Ethical duty as physician is to tell the patient.
214
Why is the amount of oxygen in the blood in left atrium a little lower than the amount of oxygen in pulmonary capillaries?
It is lower because the oxygenated blood in the pulmonary veins mixes with deoxygenated blood in the bronchial circulation.
Note that while the actual bronchial veins send deoxygenated blood to the azygous vein and hemiazygous vein, the vast majority of the deoxygenated blood that was supplied to the lungs via the oxygenated bronchial arteries, returns through the pulmonary veins.
215
Gifts. What is the policy?
Express appreciation but DO NOT accept them ever. Even of they cost the patient no monetary value or very little. Unconscious favoritism must be avoided.
216
A man with tall stature, small firm testes, and absent body hair with bilateral breast enlargement is concerning for...
Klinefelter's (XXY), he is likely to have an increased FSH level and low testosterone.
217
E.Coli stop fermenting lactose in the presence of glucose by what mechanism?
Glucose inhibits adenyl cyclase so that reduces intracellular cAMP levels and that causes poor binding of the CAP-DNA binding domain leading to decreased expression of the structural genes of the lac operon.
Note that the repressor of the lac operon in the presence of lactose, binds to the OPERATOR region of the gene.
218
Clinical botulism by blocking the release of _____ neurotransmitter results in a _____ type of paralysis.
Acetylcholine
Results in flaccid paralysis.
219
The presence of clenched fists in a neonate is most consistent with: Edwards (18) or Patau (13)?
18 -- Edwards syndrome.
220
What is the sign of chronic infection in Hepatitis?
HepBsAg. If this persists, chronic infection is present with low infectivity.
Any presence of E antigen suggests high infectivity.
Once someone has anti-HepBsAg antibodies along with anti-core, they are considered to have cleared the infection.
221
The difference between minute ventilation and alveolar ventilation is that minute ventilation is all the air that enters the lung in one minute and alveolar ventilation is the about the air that enters in a given minute that participates in GAS EXCHANGE. Alveolar ventilation has DEAD SPACE subtracted.
Repeat.
222
The posterior cruciate ligament connects where?
The PCL connects to the medial epicondyle of the femur and prevents anterior displacement of the knee. It also connects to the posterior portion of the intercondylar area of the tibia.
223
Along with conjunctival injection, marijuana is also associated with:
Tachycardia.
224
Sweating, gigantism are associated with
Gigantism; which is associated with increased release of IGF-1 from the liver upon stimulation by Growth Hormone.
IGF-1 stimulates the Intrinsic tyrosine kinase (MAP kinase) pathway while growth hormone stimulates JAK-STAT.
225
Twinning - when does the split of the zygote have to occur for different options?
```
Monozygotic twins
After 13 days -- conjoined
Days 8-12 -- 1 chorion, 1 amnion
Days 4-8 -- 1 chorion, 2 amnions
Days 0-4 -- 2 chorions, 2 amnions
```
226
Tetrahydrobiopterin is important in the synthesis of what compounds? Especially which neurotransmitter?
Tetrahydrobiopterin (BH4) is important co-factor in the synthesis of dopa, tyrosine, serotonin, as well as nitric oxide.
Tryptophan is the precursor for serotonin. Tetrahydrobiopterin reductase is important because some cases of PKU are due to its absence.
227
How does PTH act on osteoclasts?
PTH acts on osteoclasts indirectly. It causes osteoblasts to increase the secretion of RANK-ligand and monocyte colony stimulating factor. This two factors stimulate OSTEOCLASTS.
PTH increases serum Calcium and decreases serum phosphate.
228
What is vascular, fibrinoid necrosis and neutrophil infiltration suggestive of in a transplanted organ?
Hyperpacute rejection.
229
What are the 2 signals from OSTEOBLaSTS that stimulate osteoclasts precursors to become mature, multinucleated osteoclasts?
How does estrogen fit in here?
What is the decoy receptor released by osteoBLASTS that negates this effect?
Rank-ligand and monocyte colony stimulating factor are signals from the OSTEOBLASTS to the osteoclasts to increase bone resorption. These signals are increased in the presence of PTH. Low ESTROGEN is associated with increased expression of RANK by osteoCLASTS leading to increased bone resorption.
Decoy receptor is Osteoprotegrin and it reduces bone resorption.
230
What is the correlate of CHRONIC (greater than 6 months to years) rejection of a kidney transplant? (Suggested by worsening hypertension and rising creatinine).
Obliterative vascular fibrosis. Vascular wall thickening and luminal narrowing. Interstitial fibrosis. Parenchyma atrophy.
231
What is the path of PAH in the nephron?
PAH's concentration is lowest in Bowman's space because it is similar to its concentration in the plasma there. PAH is freely filtered and NOT ABSORBED by any part of the nephron. It is secreted by CARRIER-MEDIATED ACTIVE TRANSPORT in the proximal tubule.
232
In a positively skewed distribution, what is the relationship of the mean, median, and mode?
If a distribution is positively skewed, it means it has a long positive tail the most affected value is the mean which will be greater than the median. The median will be greater than the mode.
233
What part of the intestine is ALWAYS involved in Hirschsprung's disease due to the migration pattern of neural crest cells?
Rectum. Note that tone of the anal sphincter is usually increased.
234
Which embryologic structures FAIL to develop in DiGeorge syndrome
3rd and 4th pharyngeal pouch.
235
Loss of contraction of the anal sphincter in response to pinprick (anocutaneous reflex), saddle anesthesia, low back pain, bowel and bladder dysfunction, and loss of ankle-jerk reflex are suggestive of...
What nerve roots are affected???*
Cauda equina syndrome!
Nerve roots - S2-S4. Pudendal nerve is included here.
236
Flaccid paralysis of the bladder and rectum, impotence, and saddle anesthesia (S3-S5) corresponds to what syndrome? At what level is the injury?
Conus medullaris syndrome - at L2. Note that L2 also innervates the gluteal region inferior to the iliac crests and anteriorly the thigh inferior to the femoral triangle and inguinal ligament.
L3, L4 contribute to the femoral nerve and knee-jerk reflex.
237
What are associations between common drugs of abuse and their most commonly associated causes of death?
PCP - violence and trauma lead to death.
Cocaine - myocardial infarction and stroke
Opioids - respiratory depression
238
What glands are responsible for body odor?
What glands are responsible for secreting most of the sodium chloride in sweat?
Apocrine glands. They release an ODORLESS substance that acquires an odor upon bacterial decomposition of the substance.
The eccrine/merocrine glands secrete the watery fluid of sweat.
Holocrine - associated with sebaceous glands.
239
If someone has high aldosterone, Conn's syndrome, what will be his/her symptoms?
Hypertension (due to increased Sodium retention), HYPOkalemia, and METABOLIC ALKALOSIS. The Hypokalemia results in muscle weakness and the hypokalemic alkalosis results in paresthesias.
There is NOOO weight gain in the above syndrome which is called Conn's syndrome. Weight gain is associated with Cushing's which is a result of GLUCOCORTICOID excess.
240
What syndrome are diarrhea and flushing associated with?
Carcinoid syndrome which is associated with release of serotonin from neuroendocrine cells in the GI tract.
241
When looking at a drug dose vs response graph,
A shift up or down corresponds to _____
A shift to the right or left corresponds to _____
What is the effect of adding a non-competitive antagonist? (I.e. Binds to allosteric site)
A shift up or down corresponds to a change in efficacy. A non-competitive antagonist will decrease efficacy and shift the curve DOWN.
A shift left or right corresponds to a change in potency.
242
If a man is able to achieve morning tumescence, that suggests that the physiologic machinery to achieve an erection is intact and his erectile dysfunction made be due to psychologic cause.
Repeat.
243
What is bromocriptine?
It is a dopamine AGONIST.
244
What is reserpine?
Reserpine is an anti-hypertensive medication -- can cause severe depression.
245
Recall that of the benzodiazepines, the LOT ones are SAFE to use in liver disease. Chlordiazepoxide is not safe to use in liver disease.
Repeat.
246
If a 46 XY fetus has normally functioning Leydig cells and no Sertoli cells, what structures will develop?
Male and female internal genitalia and make external genitalia.
Note that testosterone is what causes persistence of the Wolffian ducts (male internal genitalia). Muellerian inhibiting factor which would have been secreted by Sertoli cells causes involution of the paramesonephric ducts which become the female structures.
247
What is the pattern of resistance along the airways?
The upper airway (everything pre-trachea) accounts for half of airflow resistance. From the trachea onwards, airway resistance in the first 10 generations of bronchi contributes most to total airway resistance of the lower respiratory tract. The medium sized bronchi have MORE airway resistance than the trachea due to turbulent airflow and then the smallest airways have the least resistance contributing less than 20% of airway resistance.
248
In the process of INFORMED consent when a foreign language is spoken, the appropriate course of action even in the presence of a translating family member is to use...
A PROFESSIONAL foreign language interpreter. Use a family member only in an EMERGENCY.
249
Uric acid, cystine, and calcium oxalate stones are promoted in ______ pH.
Acidic pH.
Only calcium phosphate and struvite stones like alkaline pH.
250
Galactose enzyme defects -- explain what enzymes are involved and what builds up. If you have a child with only clouding of the lens, what enzyme is affected?
Only lens (cataracts) - you have galactitol formed by ALDOSE REDUCTASE from the excess galactose -- the galactitol is deposited in the lens. This is due to Galactokinase deficiency which would have made galactose - 1 - phosphate were it functional.
If you have systemic symptoms (HSM, cataracts, failure to thrive, inability to tolerate breast milk, hyperchloremic metabolic acidosis) then uridyl transferase is the deficiency and what is building up is galactose 1 phosphate. This is classic galactosemia. The treatment to limit LACTOSE and breast milk. The common sepsis associated is E.Coli sepsis.
Osmotic damage is the mechanism of the cataracts forming.
251
What is the role of CFTR in the creation if sweat?
The role of CFTR is to facilitate the creation of HYPOTONIC sweat from the eccrine glands. It resorbs chloride as the fluid makes its way through the eccrine glands and sodium follows the chloride back in to the cells so that sweat ends up being hypotonic.
However, in patients with cystic fibrosis, CFTR is defective so their SWEAT is full of SODIUM and CHLORIDE.
CFTR does not play any role in the kidneys.
252
What is streptomycin?
Streptomycin is an Aminoglycoside. It binds to the 30S subunit and prevents initiation. The other Aminoglycoside to keep in mind is Tobramycin.
Tetracyclines block amino-acyl tRNA at the A site.
Chloramphenicol blocks peptidyltransferase.
253
What is the primary site of entry of cryptoccoccus neoformans into the body?
LUNGS!!! It only exists as a yeast.
It is not the nasopharynx.
254
What is number needed to harm?
It is 1/(attributable risk) meaning 1/(adverse event treatment - adverse event placebo).
It is important to correctly identify the adverse event. Is it death, disability etc? Makes the math easier to set up.
255
What are neurophysins?
Neurophysins are the carrier proteins that are each unique to vasopressin and oxytocin. They carry these hormone from their site of production in the paraventricular and supraoptic nuclei to their site of release in the posterior pituitary.
256
MHC Class II in an antigen presenting cell is loaded in an acidified lysosome after the cell has endocytosed or phagocytosed the protein of interest.
Repeat.
257
MHC Class I on the other hand, takes an internal route involving proteins being degraded in the proteasome, then going to rough ER then Golgi.
Repeat.
258
How do fibrates work and how does their use promote developing gallstones?
Fibrates block 7 alpha hydroxylase which reduces conversion of cholesterol to bile acids causing build up of cholesterol in bile leading to excess secretion of cholesterol in bile.
259
A neonate has swelling of the hands and a posterior neck mass composed of cystic spaces separated by connective tissue rich in lymphoid aggregates.
What is the neck mass?
What genetic syndrome is associated?
The neck mass is a cystic hygroma
It is common in TURNER's syndrome. Where there are no secondary sexual characteristics (due to no estrogen).
260
What is adrenogenital syndrome?
Congenital adrenal hyperplasia
261
What is testicular feminization syndrome?
It is androgen insensitivity syndrome. There is a defect in testosterone receptors. 46, XY babies appear phenotypically as female but there is a blind ended vaginal pouch (lower portion of vagina) with no uterus.
262
What is the mechanism of macrolides like erythromycin? It is the same mechanism of related drug clindamycin.
They block TRANSLOCATION during the elongation phase at the 50s subunit. It inhibits ribosome from moving along the mRNA that is being translated to a protein.
263
The site on the immunoglobulin just above the Fc receptor region is where complement attaches.
Disulfide bonds hold the immunoglobulin Y shape together at the center.
Repeat.
264
What is the virulence factor in Staph Aureus's peptidoglycan layer that it uses to evade the immune system?
Protein A which binds the Fc portion of IgG at the site where complement would have bound thereby decreasing production of C3b, opsonization, and phagocytosis.
265
What virulence factor do Streptococcus pneumonia and Neisseria gonorrhea share in common?
IgA protease.
266
PERMANENT central diabetes inspidus is associated with injury to the ________
Whereas central diabetes inspidus that improves is probably due to injury to ______
Permanent - hypothalamic nuclei
Transient - posterior hypophysis. Activity likely returns due to hypertrophy of producing cells.
267
Enterococcus resistance mechanism:
Enterococcus are resistant to aminoglycosides transferring different chemical groups like acetyl groups to the antibiotic to prevent it interacting with their ribosome.
Vancomycin resistance in enterococcus occurs when they acquire a plasmid that codes for a ligase (VanA ligase) that changes their D-Ala, D-Ala wall to D-Ala, D-lactate.
Enterococcus resistance to penicillins like ampicillin come from producing a beta-lactamase and having low affinity penicillin binding proteins.
268
Which histones make up the nucleosome?
Which one is outside?
Histones 2,3,and 4 are at the core of the nucleosome.
Histone 1 is outside it.
269
A watery penile discharge, negative for Gonococcal infection that is followed two weeks later by conjunctivitis, right knee pain, and vesicular rash on palms and soles is concerning for...
Reactive arthritis following a genitourinary (Chlamydia) or enteric infection (Salmonella, Yersinia, Cloristidium difficile, Campylobacter, Shigella). Clinical presentation: Oligoarthritis, dactylitis, enthesitis. Association with HLA-B27.
Skin manifestations: keratoderma blennorhagicum, circinate balantis
Oral ulcers
270
If you suspect elder abuse, speak one on one with the patient first.
Repeat
271
Where does INTRAventricular hemorrhage in a preterm baby originate?
The germinal matrix - region in sub ventricular zone where neurons and glial cells migrate out of during brain development. IVH is associated with long-term neurodevelopmental impairment.
Increased frequency in premature babies and low birth weight babies.
272
How do you calculate renal BLOOD FLOW?
RBF = RPF / (1- HCT).
Recall RPF = PAH clearance.
273
Where in the kidney does Lithium exert its action in the setting of diabetes insipidus?
The collecting tubule. Lithium antagonizes the effect of vasopressin (ADH) on the collecting tubules and collecting ducts. Symptoms usually resolve on discontinuation but after years of chronic use, can be permanent.
274
A gram positive rod with a NARROW zone of Beta-hemolysis that grows well at 22C and can multiply at temperatures as low as 4C is concerning for...
How is it killed?
Listeria. Because it is intracellular, T-cell mediated immunity is required to kill it.
275
Mutations in Trypsin's ability to cleave itself are associated with what clinical condition?
Hereditary pancreatitis.
276
How does the INACTIVATED flu vaccine work?
It works by facilitating the generation of neutralizing antibodies against hemagglutinin PREVENTING ENTRY of influenza into cells.
277
How is epinephrine synthesized and what hormone is this enzyme stimulated by?
Epinephrine is synthesized from norepinephrine by the enzyme phenylethanolamine-N-methyl transferase and it is under the influence of cortisol.
278
Air in the gallbladder and in the biliary duct suggest?
gallstone ileus -- where a large gallstone has created a cholecysenetric fistula. The large gallstone usually comes to rest at the ileocecal valve in the ileum. Cholecystectomy is usually NOT required. What is required is SURGICAL REMOVAL OF THE STONE. Patients present with small bowel obstruction symptoms. Stone can be visualized on abdominal X-Ray.
279
A patient who first has a serum-sickness like picture and then experiences a rise in ALT and AST is concerning for...
Acute Hepatitis B infection
280
What causes fine skin wrinkles as we age?
Decreased PRODUCTION leads to net loss of collagen and elastin from the dermis.
281
A 15 year old boy with gait ataxia who also has kyphoscoliosis, pes cavus, and absent joint and position sense is suggestive of what inherited disease? What is he at risk for dying of?
Friedrich's ataxia -- it is an autosomal recessive condition where spinocerebellar tracts and dorsal columns degenerate. common cause of death is hypertrophic cardiomyopathy.
282
What is the nature of the vaccine for meningitis?
What is the best prophylaxis for family members of someone who is infected?
Capsular polysaccharide vaccine
Best prophylaxis for exposed family members: Rifampin (you cry and pee orange). Also, rifampin RAMPS up cytochrome P450 meaning little warfarin.
283
What is the long-term sequelae of hydrocephalus in a child which presents as irritability, poor feeding, increased head circumference, enlarged ventricles on CT?
Muscle hypertonicity (spasticity), visual disturbances, and learning difficulties. This is due to stretching of the periventricular pyramidal tracts.
284
Which immune cell has CD40?
Which has CD40 ligand?
Describe the process of B cell activation.
B cell has CD40
T cell has CD40 ligand.
A mature B cell encounters an antigen and becomes activated! It makes clones of itself. Some of these activated B cells become short-lived plasma cells and secrete IgM (T-cell INDEPENDENT).
The vast majority of the activated B-cells go to the lymph node to form a GERMINAL follicle which is the site of proliferation of activated B cells in the lymph node. A portion of these B cells become long-lived memory cells but the vast majority will be antibody secreting plasma cells.
Late in this active primary response of the B-cell, they interact with an ACTIVATED T-cell expressing CD40 ligand and undergo somatic hypermutation that leads to affinity maturation and immunoglobulin isotype switching to make IgG etc. In isotype switching, only the heavy chain changes.
This is NOT VDJ recombination.
285
What end of tRNA is the amino acid group attached?
3' - 3 prime end.
| The side loop closest to the 3' end is the ribothymidine, pseudouridine, cytosine loop.
286
Where does VDJ recombination occur?
In the bone marrow! To maturing B-cells.
287
What is the difference between promoter regions and enhances/repressors in terms their function and location?
Enhancers and repressors can be located ANYWHERE along the gene. Even within it. Enhancers increase transcription of a gene by binding to transcription factors which are bound to promoter regions.
Promoters are ALWAYS upstream. Promoters are the binding site for RNA polymerase II (makes mRNA) and transcription factors. There are 2 types of promoters in EUKARYOTES 25 bases upstream is the TATA box, 70- 80 bases upstream is the CAAT.
288
If stratified analysis of an initial result shows an EVEN MORE PROFOUND, STATISTICALLY SIGNIFICANT relationship when the potential subgroups are stratified in analysis the phenomenon is ________
If stratified analysis of an initial result shows a WEAKER or STATISTICALLY INSIGNIFICANT result (look at p-value) when subgroups along the lines of variables that are potential other influencers of the results, the phenomenon is ________
Effect modification
Confounding
289
What is the role of IL-5?
IL-5 is secreted by T-helper 2 cells and it recruits and activates eosinophils!!! It has a role to play in extrinsic allergic asthma.
290
What bacterial agent that causes pneumonia must be cultures on charcoal yeast supplemented with L-cysteine and iron to survive??? Here's a hint: it also best visualized with silver stain.
How do you diagnose it?
Legionella
Diagnose legionella with the urine antigen test.
291
If a child demonstrates symptoms of both absence seizures and generalized tonic-clonic seizures what drug ALONE is best to treat both?
How does this drug work?
Valproic acid.
It increases sodium channel inactivation and increases GABA by inhibiting the enzyme, GABA transaminase.
292
(Must know) what is the mechanism of action of morphine?
Morphine binds to opioid mu receptors and modulates synaptic transmission -- opens K+ channels and closes Ca2+ reducing synaptic transmission. It thereby inhibits the release of ACh, NE, 5-HT, glutamate, and substance P.
293
How do benzodiazepines work?
Appropriate treatment of overdose:
Benzodiazepines work by increasing GABA-A action. The do this by increase the FREQUENCY of chloride channel opening.
Overdose: Flumazenil
294
How does phenytoin work?
It increases sodium channel inactivation. It exhibits zero order kinetics and ramps up the cytochrome P-450 system too.
295
How does Gabapentin work?
It inhibits high voltage inactivated Ca2+ channels.
296
Carbamazepine, phenytoin, phenobarbital, rifampin, and griseofulvin all share the following activity?
Ramp up cytochrome P-450 system.
297
How do barbiturates work?
What is the appropriate management of overdose on barbiturates?
They work by increasing the action of GABA-A. It does this by increasing the DURATION of Chloride channel opening.
Overdose: Supportive therapy.
298
How does Zolpidem (Ambien) work?
It acts at the BZ1 subtype of the GABA receptor. It can be reversed by Flumazenil even though Zolpidem is technically NOT a benzodiazepine.
299
What is blood solubility of an inhaled anesthetic reflective of?
How about lipid solubility?
It is reflective of speed of induction. A highly BLOOD soluble substance will have a slower induction while a less BLOOD soluble substance will have a more rapid induction.
LIPID solubility relates to POTENCY. The more LIPID soluble an inhaled anesthetic is, the more POTENT it is. Lipid solubility is related to MAC. Recall 1/MAC is proportional to potency.
300
What is the effect of INHALED anesthetics on cerebral blood flow?
They INCREASE cerebral blow flow and RECUCE cerebral metabolic demand.
301
How do arylcyclohexylamines like Ketamine work?
Block NMDA receptor. Increases cerebral blood flow.
302
How does Propofol work?
It potentiated GABA-A. Rapid anesthesia induction.
303
How can you tell which LOCAL anesthetics which end in -Caine are esters vs amides?
The Amides have 2 I's in their name!!!
304
What is the mechanism of succinylcholine? What is it used for?
Succinylcholine is a DEPOLARIZING neuromuscular blockade agent. It is an acetylcholine receptor AGONIST.
305
In COPD or asthma, the RV/TLC ratio is much increased!!!! The Residual volume is the main increase.
Repeat.
306
An inhaled anesthetics destination is the brain. To get there it has to travel from the lungs to the blood to the brain. What is the implication of the arteriovenous gradient?
The AV concentration gradient relates ONSET of action of inhaled (gas) anesthetics. It represents tissue solubility because if the difference (AV gradient) is large, it means tissue solubility is HIGH. If tissue solubility is HIGH, then more of the inhaled anesthetic is needed to build up in the blood to then build up in the brain. This translates to a slower ONSET of ACTION.
307
How should incidence be calculated?
of new cases a year / (Total population - those already with disease).
308
What is the BIGGEST difference in response to the killed, inactivated polio vaccine vs the oral polio vaccine?
The duodenal IgA response! To generate mucosal immunity, it is important to administer the vaccine at the desired site and to administer a live vaccine!
309
What mnemonic reminds me of relationship of inferior Epigastric vessels and inguinal hernias?
MDs LIE. Medial direct inguinal hernia, lateral indirect inguinal hernia.
310
In lead poisoning what substance along the porphyrin synthesis pathway:
What vitamin is important for this pathway?
Delta-aminolevulinic acid.
Pyridoxine Vitamin B6.
311
An elderly patient who develops difficulty swallowing, choking, coughing and recurrent aspiration is concerning for...
Developing a Zenker diverticulum which results from IMPAIRED MUSCLE RELAXATION of circopharyngeus and other muscles of pharynx during swallowing. This diverticulum is a false diverticulum.
312
Hemoglobin C migrates the least on gel electrophoresis and it results from a _____ mutation
MISSENSE.
313
What drugs INHIBIT warfarin synthesis?
Isoniazid, trimethoprim, Fluconazole and cimetidine.
314
Which nucleus of the thalamus receives gustatory and trigeminal SENSORY input?
VPM -- recall medial is face.
Lateral is body -- spinothalamic and medial lemniscal input go to VPL.
315
What is the impact on prevalence of a therapy that prolongs survival but does not actually CURE?
It INCREASES prevalence.
316
When in the cardiac cycle does the opening snap of mitral stenosis occur? When is this in relation to the aortic valve closing and what is the relationship between the left ventricular and left atrial pressures at this time?
The opening snap of mitral stenosis corresponds to the tensing of abnormal mitral valve leaflets AFTER the mitral valve cusps has opened. It happens AFTER the aortic valve closes. The mitral valve does not open until Left ventricular pressure falls below left atrial pressure.
317
What kind of damage to DNA do Ionizing radiation (X-rays and gamma rays) cause?
They cause double stranded DNA breaks that can be repaired by homologous or non-homologous joining.
318
How is UV radiation induced damage to DNA repaired?
UV radiation causing thymidine dimers. It is repaired by nucleotide excision repair which begins with an endonuclease.
This UV specific endonuclease is what is missing in Xeroderma pigmentosum. (Autosomal recessive).
319
What should migratory Polyarthritis make me think of?
Rheumatic fever - Strep A
320
What does aromatase do?
| Where is it located?
It converts androgens (testosterone and DHEA) into estrogens (estrone, estradiol). Estradiol is active estrogen.
Location: peripheral tissues.
321
What percentage of the filtered amount of the following substances is excreted by the kidney?
```
Sodium
Urea
Inulin
PAH
Glucose
```
Sodium - only 1% is excreted regardless of concentration within relatively physiologic range.
Urea - 55% is excreted at all concentrations similar to caveat above.
Inulin - 100% excreted. Recall, Inulin is neither secreted nor absorbed.
PAH - > 100% excreted because it is secreted!!!
Glucose -- excreted in a concentration dependent manner. completely absorbed below threshold point of the Na+ co-transporters in the proximal convoluted tubule.
322
What are the 3 drugs used for MRSA? How do they each work and what are their side effects.
Vancomycin - Binds to D-alanine D-alanine glycopeptide. Adverse Effects: Red Man syndrome, Nephrotoxicity
Daptomycin - creates transmembrane channels that lead to depolarized cell membrane. Adverse effects: myopathy and CPK elevation; inactivated by pulmonary surfactant so useless against pneumonias.
Linezolid - inhibits protein synthesis by binding the 50S subunit. Adverse effects: Thrombocytopenia, Optic neuritis, High risk of serotonin syndrome.
323
High levels of what two substances reduce the risk of forming a gallstone by increasing cholesterol solubility?
Bile salts and phosphatidylcholine
324
It takes about 10-14 days of being at high altitude for the effects of the EPO in terms of increased red blood cells to be seen. Renal compensation for the respiratory alkalosis begins about 48hrs in.
Repeat
325
What bacteria has antiphagocytic D-glutamate capsule?
Anthrax. Widened mediastinum. Bacillus anthracis. Gram positive rod. Mediastinum widened due to hemorrhagic mediastinitis.
326
What class of fungal drugs INHIBIT cytochrome P-450 and thereby increase toxicity of drugs processed by it?
What is their anti fungal mechanism of action?
-Azoles
They work by inhibiting the demethylation of lanosterol into ergosterol. (Cell membrane)
Also note that cimetidine and omeprazole INHIBIT cytochrome P-450 as well
327
What part of the fungus structure is the target for caspofungin?
Is it cell wall or cell membrane?
Cell wall!
328
Note nitroglycerin and isosorbide undergo considerable first pass metabolism by liver if taken orally! What nitrate drug has high oral bioavailability instead?
Isosorbide mono nitrate.
329
To what common drug are the vast majority of catalase positive, coagulase negative Staph resistant? E.g. Staph epidermis.
What drug is best to treat these infections especially if bacteremia occurs?
Methicillin!
Vancomycin
330
IT IS unethical for a physician to date CURRENT patients. However, they may be romantically involved with former patients.
This is NOT the case for psychiatrists. They can NEVER be involved with a patient.
Repeat.
331
Which cell secretes a substance that controls iron storage and release by other cells involved in iron homeostasis?
What conditions stimulate its secretion? Inhibit its secretion?
Hepatic parenchymal cells; Hepcidin.
Hepcidin influences body iron storage by its interaction with FERROPORTIN, a transmembrane protein which is responsible for secreting iron into the circulation. When Hepcidin binds FERROPORTIN, FERROPORTIN is internalized and degraded. This decreases release of iron by macrophages.
Hepcidin secretion is stimulated by inflammation and high iron stores. It is inhibited by hypoxia and eryrhropoiesis.
332
If an incorrect amino acid is loaded unto a tRNA and misses the HYDROLYZING ability of some of the amino-acyl tRNA synthetases, what happens?
The incorrect amino acid is incorporated into the peptide.
333
Where are acoustic neuromas usually located?
Between the cerebellum and lateral pons.
334
Where in the thymus does positive selection for TCR occur?
Where in the thymus does negative selection occur?
Positive selection occurs in thymus cortex. -- thymus cortical epithelial cells.
Negative selection - thymic medullary epithelial and dendritic cells.
335
What major side effect is clozapine associated with? What is another adverse effect associated with it?
Agranulocytosis;
| seizures.
336
What kind of transmembrane protein CFTR?
What chromosome is the mutation on?
ATP-gated!
Chromosome 7!
337
What is the histology of rhizopus vs Aspergillus?
Rhizopus looks like ribbons and branches at a wide angle!!!
Aspergillus is separate and branches at acute angles that end up looking V-shaped.
338
Natural protection against influenza re-infection is confirmed by ...
IgG antibodies against hemagglutinin in circulation and IgA antibodies in the nasopharynx.
339
Note: Incidence per 100,000 ppl is NOT the same as incidence overall!
Repeat.
340
Chemoreceptors:
What respiratory changes are sensed by the central chemoreceptors?
Carotid bodies?
Central chemoreceptors are in the medulla and they sense changes in pH -- so they are influenced largely by PaCO2 levels
Peripheral chemoreceptors are in the carotids and aortic bodies and largely sense HYPOXEMIA. (Glossopharyngeal nerve)
341
What is the role of pulmonary stretch receptors?
They include the myelinated and unmyelinated C fibers and their job is to protect the lungs from hyperinflation. They regulate the duration of inspiration depending on lung distension.
342
What is Bumetanide?
It is a loop diuretic
343
What osmotic diuretic drug can cause pulmonary edema if used too aggressively to reduce intracranial pressure?
Mannitol
344
Why are people susceptible to repeat gonorrheal infection?
What drug is Gonorrhea developing increasing resistance to?
Susceptible due to antigenic variation.
Resistance to penicillin. Gonorrhea remains susceptible to cephalosporins.
345
In what pH range does uric acid precipitate? In what pH range is it soluble?
What drug can reduce uric acid production?
Uric acid precipitates at low, acidic pH.
It is soluble if urine is alkalinized!
Allopurinol prevents uric acid production.
346
Ataxia, dermatitis, and diarrhea are suggestive of?
B3 - Niacin deficiency. This can be seen in Hartnup disease where renal and intestinal absorption of tryptophan is defective. Tryptophan, is a precursor of Niacin.
347
What structure is most likely to be injured by the left 12th rib?
Left kidney
348
When looking at acid base status, keep in mind that compensation for primary respiratory processes takes at least 24 hours. If metabolic compensation is not present, it suggest an ACUTE cause.
Repeat
349
In the setting of intimate partner violence, what is the most important thing to establish:
That the patient has a safe place to go in an emergency.
350
What are Strep pneumoniae's bacteria culture characteristics?
```
Alpha hemolytic (as is strep Viridans)
Bile soluble, Optochin sensitive.
```
Note that strep Viridans is alpha-hemolytic, bile insoluble, optochin resistant.
351
What are the HYPER problems associated with Thiazide diurectics?
What are the HYPO problems associated with them?
Hyperuricemia, hypercalcemia, Hyperlipidemia - increase both cholesterol and LDL, hyperglycemia
Hypokalemia, hypotension.
352
P-450 inducers ( lower available drug concentration)
Rifampin, griseofulvin, carbamezepine, barbiturates, CHRONIC alcohol consumption.
353
P-450 inhibitors
Fungal -Azoles, cimetidine, omeprazole, isoniazid, MACROLIDES, GRAPEFRUIT JUICE
354
What is the equation that includes hematocrit, RBF, and RPF?
RPF = (1-Hct) RBF
355
What are NNRTI HIV drugs? What is unique about them on entering the cell?
NNRTI's are nevirapine, efavirenz, delavirdine. These do not require phosphorylation on entering the cell.
Watch for hepatotoxicity in first 6 weeks. SJS in first 18 weeks.
356
What is the target of E.Coli Shiga like toxin and Shigella toxin?
They inhibit the 60S ribosome subunit (by removing adenine from rRNA).
357
What is the mechanism of diphtheria toxin and Pseudomonas exotoxin A?
It inhibits elongation factor 2.
358
If misfolded proteins accumulate in a cell, what process is likely missing?
Ubiquitination. Recall Ubiquitination is ATP dependent.
359
What famous system is active in cardiac failure?
RAAS - do not forget role of things like arteriolar resistance as a result of this activity.
360
What is the marker for monocytes and macrophages?
CD 14
361
High levels of arginine in CSF, spastic paresis, and choreathethoid movement are concerning for...
Argininase deficiency. Which is the last portion of the urea cycle. Arginase converts arginine into ORNITHINE and UREA.
362
What two molecules does vasopressin (ADH) increase the absorption of?
If a patient with polyuria responds to a shot of vasopressin, what form of DI could they have?
Urea and water!
Central DI
363
If a virus obtains its envelope from the nuclear membrane, what family of viruses must it belong to?
Herpesviridae. It can be CMV!
364
How do medications like pioglitazone exert their effect?
What is the consequence of this mechanism of action?
Thiazolidendiones like pioglitazone work to decrease insulin resistance by binding PPAR-gamma (peroxisome proliferator activated receptor gamma) which is a transcription regulator of the genes involved In glucose and lipid metabolism. TRANSCRIPTION MODULATION. The most important gene activated by PPAR-gamma is adiponectin. Adiponectin is normally LOW in people with Type 2 diabetes.
365
What drug is commonly associated with the following adverse effects: gingival hyperplasia, nystagmus, ataxia?
phenytoin!
At 3-4 months out, 50% of people have gingival hyperplasia through the PDGF mechanism that causes gingival macrophages to stimulate proliferation of gingival cells and alveolar bone.
366
While most cases of achondroplasia are sporadic, what is the inheritance pattern of the inherited form which accounts for 15% of cases?
What gene is affected?
Autosomal dominant inheritance.
FGF receptor 3 gene. Gain of function mutation. Anyone who is alive beyond shortly after birth with achondroplasia is heterozygous because homozygous individuals die shortly after birth.
367
An individual with RECURRENT C.diff colitis who would like a bacteriocidal oral antibiotic with little systemic absorption needs:
Fidaxomicin.
368
What drugs prolong QT?
```
Some Risky Meds Can Prolong QT
Sotalol
Risperidone
Macrolides
Chloroquine
Protease Inhibitors (-navir)
Quinidine
Thiazides
```
369
Why should non-selective beta blockers like propanolol, timolol, and nadolol be avoided in patients with diabetes?
Non-selective beta blockers blunt adrenergic symptoms of hypoglycemia (due to NE and epinephrine) and inhibit hepatic gluconeogenesis and peripheral glycogenolysis and lipolysis.
Use selective beta-1 blockers only.
370
A stroke that results in complete, purely sensory loss on one side of the body localizes to...
Thalamus -- CONTRALATERAL to the affected side. There is usually loss of propioception too which causes difficulty ambulating but motor strength is the same.
371
Oligodendrocyte apoptosis is implicated in multiple sclerosis!
Repeat
372
High output cardiac failure and neurological symptoms including neuropathy are suggestive of ...
Thiamine deficiency - wet beriberi
373
What is length constant?
What is time constant?
Length constant is how far along an axon an electrical impulse can propagate. DEMYELINATION INCREASES LENGTH CONSTANT.
Time constant is the time it takes for a change in membrane potential to achieve 63% of the new value. DEMYELINATION increases time constant leading to slower impulse conduction.
374
Redistribution of fat from extremities to trunk is caused by two types of drugs:
Glucorticoids (Exogenous Cushing syndrome) and HAART therapy -- specifically protease inhibitors (lipodystrophy). Lipodystrophy involves redistribution of fat to the abdominal viscera and supraclavicular area etc.
375
Where does blood in a subdural hematoma acculumate?
Between the dura mater and the arachnoid.
376
What is the pathogenesis of pulmonary hypertension in left heart failure?
Higher diastolic filling pressures are transmitted backwards and cause PULMONARY VENOUS CONGESTION that results in endothelial injury. This results in decreased NO secretion by the endothelium of the pulmonary vasculature and more ENDOTHELIN (vasoconstrictor) secretion leading to increase vascular tone and remodeling over time with increased smooth muscle cell proliferation. However, this remodeling is usually partially reversible if it occurs due to heart failure.
377
What is the cell of origin of glioblastoma multiforme?
Astrocytes; 40-70 yrs old
378
What is the role of riboflavin (B2) in the body?
It is the precursor to coenzymes FMN and FAD. FAD participates in the TCA cycle as the co-enzyme of SUCCINATE dehydrogenase in the conversion of SUCCINATE to FUMARATE.
It's deficiency can be associated with corneal neovascularization.
379
What is diphenoxylate?
It is an anti-diarrheal structurally relate to meperidine that binds the opiate mu receptor in the GI tract and slows motility. It is an opioid mu agonist.
380
What is unique about E.Coli O157:H7 in terms of sorbitol and glucoronidase
It cannot ferment sorbitol and it does not produce glucoronidase! This distinguishes it from other stains of E.Coli!!!
381
Coxsackie A virus, echovirus, poliovirus, and Hep A virus are all RNA, picorna viruses and they have one more thing in common:
They are all enteroviruses! They all are capable of infecting or colonizing the lower GI tract.
Rhinovirus is a picorna virus that CANNOT survive in the stomach. It is acid-labile!
382
Diplopia, dysphagia, and dysphonia. Including a situation with difficulty swallowing and blurred vision should be concerning for...
Botulism toxin ingestion. Usually 12-46hrs after is when symptoms begin.
383
Only succinylcholine is the muscle relaxant that has 2 different phases. In its first phase, neostigmine will actually augment its effect. In its second phase, neostigmine will revert it.
Repeat.
384
What is calcipotriene?
It is a topical Vit D analog that binds to the Vitamin D receptor and INHIBITS keratinocyte proliferation and differentiation. Other similar drugs calcitriol and talacalcitol. The vitamin D receptor is a NUCLEAR transcription factor. It is used in psoriasis.
385
Where is rRNA synthesized?
Nucleolus (within the nucleus).
386
What is the mechanism of action of triptans?
They are serotonin receptor agonists. 5-HT 1B and 5-HT 1D. They are used as abortive therapy for migraines.
387
Thiopental is an...
Short acting barbiturate used for anesthesia. After equilibration with the brain, it rapidly distributes to the skeletal muscle and adipose.
388
How long does it take methotrexate to work in RA?
What is the best immediate therapy but not great for long-term?
It takes methotrexate weeks.
Glucocorticoids are best immediate therapy.
389
Urinary schistosomiasis is associated with...
Hepatic schistosomiasis and intestinal schistosomiasis
S hematobium
S japonicum and S mansoni cause intestinal and hepatic schistosomiasis.
390
What is Diphyllobothrium Latum associated with
B12 deficiency. Megaloblastic anemia.
391
Over expression of MHC Class I, CD8+ infiltration and proximal muscle weakness is concerning for
Polymyositis.
392
How can you distinguish leukemoid reaction from CML?
In leukemoid reaction, alkaline phosphatase will be increased. In CML, it will be decreased.
393
How does Valsalva help abolish Supraventricular tachycardia?
It does so through vagal stimulation which then increases refractory period in the AV node. If that does not work use adenosine for SVT.
394
What key biosynthesis reactions require NADPH as a co-factor in the body?
Fatty acid, cholesterol, and steroid synthesis.
395
As far as Turner's syndrome is concerned (I.e. monosomy X), what is the mechanism of the genetic abnormality?
Loss of parental chromosome during MITOSIS is responsible for most cases of monosomy X.
396
Sorbitol injury underlies both the formation of cataracts in diabetes and the peripheral neuropathy (Schwann cell damage).
Repeat.
397
What is the pathophysiology of acute rejection of a cardiac transplant (1-4 weeks out) which usually presents similarly to heart failure?
Dense lymphocytic infiltrate.
398
What is the effect of constriction of the ureter on GFR?
It decreases GFR!
399
What disease is being ApoE4 genotype associated with?
Alzheimer's Dementia
400
What genotypes are associated with Early-onset Alzheimer's?
APP - chromosome 21, presenilin 1 and presenilin 2.
401
What compensatory mechanism can work in the setting of moderate increases of CVP in the setting of Right heart failure to avoid peripheral edema?
Increase lymphatic outflow resorbing interstitial fluid. Only when this compensatory mechanism is overwhelmed does peripheral edema occur.
402
What is rheumatoid factor?
It is an IgM molecule specific for the Fc portion of self IgG. It is secreted by B cells that have come in contact with cartilage auto-antigens.
Anti-CCP even more specific for rheumatoid arthritis.
403
What is benefit of beta-blockers, especially Carvedilol, in CHF?
They slow down the progression of heart failure and reduce all-cause mortality. Their mechanism of action results in reduced heartrate and reduced afterload.
404
The t(15;17) translocation is associated with what disease?
Acute myelogenous leukemia. The acute promyelocytic variant. PML/RAR-alpha. Retinoic acid alpha.
405
Bile acid resins and fibrates _______ (increase or decrease) liver cholesterol synthesis thereby (increase/decrease) risk of cholesterol stone
Bile acid resins - cholestyramine, fibrates INCREASE liver cholesterol synthesis and thereby increase risk of cholesterol gallstones.
406
What is the characteristic of pharmacologic agents that redirect bloodflow away from ischemic areas in the heart?
They are selective coronary arterial vasodilators like adenosine and dipyradamole. Because ischemic areas of the heart are already maximally vasodilated under normal conditions, these medications actually reduce collateral bloodflow to these areas when they vasodilate the rest of the coronary vasculature. This is known as coronary steal.
407
What HIV drug binds to gp41 and blocks conformational changes necessary fusion of viral and cellular membranes?
Enfurvirtide
408
What is the order in which you must treat active diphtheria: (order of importance is key)
What is the common cause of death:
1. Diphteria anti-toxin (the toxin deactivates elongation factor 2 and thereby inhibits protein synthesis) -- passive immunity -- antitoxin involves the transfer of neutralizing antibodies to the patient.
2. Pencillin, erythromycin
3. DPT vaccine -- active immunization.
Cause of death: cardiomyopathy
409
What is the mechanism of action of etoposide and podophyllin?
What enzyme do they target?
Target: Topoisomerase II
Etoposide and podophyllin inhibit Topoisomerase II's ability to repair the double-stranded DNA breaks that it makes.
410
What is ritonavir?
It is an HIV protease inhibitor. Prevents assembly and maturation of virus. Non-infectious, non-functional virions produced instead.
411
What happens to lung particles at these different sizes? How are they cleared?
Less than 2 micrometer
2.5-10 micrometer
10-15 micrometer
What happens to lung particles at these different sizes? How are they cleared?
Less than 2 micrometer - phagocytosis in the alveoli
2.5-10 micrometer - get to trachea and bronchi - mucociliary transport
10-15 micrometer - upper airway - coughing, sneezing
412
Urine that darkens after standing for 24 hrs in the setting of acute abdominal pain, nausea and confusion is concerning for...
what is the pathophysiology?
What is the treatment?
Acute intermittent porphyria
It is due to PORPHOBILINOGEN DEAMINASE DEFICIENCY which results in a build up of PBG and delta-aminolevulinic acid. The ursine changes color because excess PBG gets oxidized.
The treatment and prevention is to inhibit ALA synthase which is inhibited by HEME and GLUCOSE. ALA synthase is stimulated by CYP450 inducers like alcohol, smoking, barbiturates, anti-epileptics. The inducers should be avoided as they worsen AIP.
413
What pattern does Leber hereditary optic neuropathy follow?
Mitochondrial disease
414
What TB drug can cause visual changes and what is its mechanism of action?
Ethambutol can cause OPTIC neuritis presents in conjunction with decreased visual acuity, central scotoma, and color blindness. It works by inhibiting CARBOHYDRATE POLYMERIZATION preventing peptidoglycan wall synthesis.
415
What is the mechanism of action of 5-FU and 5-deoxyuridine?
They are anti-metabolites that inhibit thymidylate synthase.
416
What is the mechanism of action of methotrexate?
It is an anti-metabolite that inhibits dihydrofolate reductase.
417
What is the mechanism of action of irinotecan and topotecan?
They inhibit Topoisomerase I which induces single stranded breaks during DNA supercooling.
418
What is phencyclidine's mechanism of action?
It is an NMDA receptor antagonist leading to excess release of excitatory neurotransmitters.
419
What is the equation for bioavailability?
F = (Area under Oral curve x IV dose)/ (Area under IV curve x Oral dose)
420
What is the term for when myocardial activity can be restored following CABG to a ventricle that has experienced CHRONIC hypoperfusion?
Hibernating myocardium refers to when chronic or persistent hypo perfusion of cardiac myocytes leads to reversible loss of contractile function.
421
Where is the ansa cervicalis located?
It innervates sternohyoid, sternothyrpid, omohyoid muscles of anterior neck. It gets its roots from C1-C3 so it is at risk in anterior neck injury above cricoid cartilage.
422
Remember that lung extends ABOVE the clavicle and ABOVE the first rib!
Repeat
423
Where is the bifurcation of the common carotid?
Just below the hyoid bone. This is where the carotid body lies.
424
What does injury to the INFERIOR thyroid artery usually cause?
Hoarseness because it runs with recurrent laryngeal nerve.
425
What does DNA polymerase 3 do in prokaryotes?
It is responsible for replication.
426
What is the pathophysiology of Paget's disease of the bone which can present as bone pain/deformity and hearing loss in elderly patient?
Increased osteoCLAST activity.
427
What does DNA polymerase I do in prokaryotes?
It replaces RNA primers!
428
What is bradykinin?
| What enzyme normally degrades it?
It is a vasodilator.
ACE degrades bradykinin.
429
What must occur for pyelonephritis to occur?
Vesicoureteral reflux. Occurs even in females. The conditions that promote colonization urethra/bladder may differ but some element of Vesicoureteral reflux is required for pyelonephritis. This reflux may be anatomic or functional (motor full bladder etc).
Recurrent infections can affection the vesicouterine junction and increase susceptibility to pyelonephritis.
430
What is pantothenic acid?
The biologically active form of pantothenic acid is coenzyme A. Coenzyme A binds oxaloacetate to form citrate. Which later goes on to form succinyl CoA.
431
What is phenylephrine?
It is an alpha AGONIST.
432
What is bethanechol?
Bethanechol is a muscarinic, cholinergic AGONIST. It promotes micturition (peeing).
You could also use an alpha-1 blocking drug for the same purpose.
433
What are Gardos channel blockers?
Gardos channel blockers are used in sickle cell disease to prevent cellular dehydration that promotes polymerization. They work by blocking the calcium-dependent (Gardos) potassium channel efflux of potassium and water which would promote dehydration.
434
What is most likely to give you SVC syndrome?
A mediastinal mass! This is even more likely than a Pancoast (superior sulcus) tumor which is more likely to present as Horner's syndrome and/or shoulder pain.
435
What drug is a blocker of GP IIb/IIIa leading to a manifestation that is similar to the pathophysiology of Glanzmann thrombasthenia which leads to an issue with platelet ________.
What molecule does GP IIb/IIIa normally bind physiologically?
Abciximab blocks GP IIb/IIIa. Blocks platelet aggregation. Very useful in setting of unstable angina or acute coronary syndrome. Especially those undergoing Percutaneous intervention.
GP IIb/IIIa normally binds fibrinogen.
Diagnosis is made by peripheral smear showing no platelet clumping and clinical presentation of mucocutaneous bleeding.
436
What is complete central DI marked by?
Complete central DI is marked by a response in urine osmolality of over 50%.
A more than 10% increase suggests central DI in general.
437
If a patient is hypotensive and bradycardic, one of which 2 nerves could be responsible?
Glossopharyngeal (carotid body - internal carotid/sinus)
Vagal (aortic arch)
Afferent fibers of both nerves go to solitary nucleus of the medulla.
438
What 3 molecules are associated with osteoCLAST activity?
Tartrate-resistant acid phosphatase, urinary hydroxyproline, and urinary deoxypyridinoline.
Urinary deoxypyridinoline is most reliable for OSTEOCLAST activity.
439
What does alkaline phosphatase signify?
OSTEOBLAST activity.
440
When do brown pigment gallstones arise?
Infection
441
When do black pigment gallstones arise?
Intravascular hemolysis.
442
Which form of bilirubin is water soluble/able to be excreted in urine/NOT albumin bound?
Conjugated bilirubin.
443
The liver takes up unconjugated bilirubin in an ______ (passive/active way), secretes conjugated, water-soluble bilirubin in a _______ (active/passive) way. Were you to block secretion of conjugated bilirubin, recall it can/will Diffuse into the circulation as it is water soluble and still be excreted in urine.
Unconjugated bilirubin taken up passively with organic anion carrier (polypeptide).
Conjugated, water soluble bilirubin secreted actively with organic anion transporter.
444
What anti-neoplastic drug is a purine analog (specifically similar to adenosine) and is resistant to adenosine deaminase?
Cladribine -- it achieves high enough intracellular concentrations due to its resistance to adenosine deaminase. It is drug of choice for hair cell leukemia.
The only other purine analog is fludarabine used for CLL. The rest of the -arabines are purine analogs.
445
What is cyclophosphamide?
Cyclophosphamide is an alkylating agent that has to be converted to its metabolites by hepatic cytochrome P450 2B.
446
Which cancer drug is converted to its active metabolite by HGPRT and is inhibited by xanthine oxidase?
Mercaptopurine
447
What is isosorbide dinitrate?
VEnodilator. Decreases cardiac output in stable angina pectoris.
448
What prazosin?
It is an alpha-1 blocker like terazosin or doxazosin useful for BPH and HTN.
449
A woman recently on a cruise ship or in a hotel who has high fever, interstitial lung infiltrates, GI symptoms (diarrhea), confusion, and could be a smoker/alcoholic/elderly is concerning for...
What electrolyte abnormality might be seen?
Legionella
Low sodium, transaminitis
Diagnosis on buffered charcoal yeast culture or urine antigen test.
450
What is the mechanism of C. Diff toxicity?
The toxins in C.diff inactivate Rho-regulatory proteins involved in maintaining actin cytoskeleton structure and in signal transduction. The result is compromise of the intercellular tight junctions.
Cytotoxin B is more Cytotoxic. A is more intestinal inflammation and fluid secretion (watery diarrhea)
451
Hyponatremia is most likely to be seen with use of which class of diurectics?
Thiazide diuretics because they are still able to maintain the corticomedullary gradient and thus still possess the ability to concentrate urine.
452
What is the major virulence factor on Group A Streptococcus (pyogenes) that prevents phagocytosis?
Protein M. Protein M also inhibits complement activation and assists with adherence in addition to inhibiting phagocytosis.
453
What does streptokinase do?
It converts plasminogen to plasmin.
454
What are Amphotericin B's major side effects? What is its mechanism of action? How does this relate to its side effects in humans?
Amphotericin B's MAIN side effects are dose-dependent nephrotoxicity, Hypokalemia, and hypomagnesemia.
It binds ergosterol in the cell membrane of fungi. In humans, to a degree, it binds cell membrane cholesterol leading to its adverse effects.
455
Amanita toxin blocks _____ synthesis by blocking ____ (enzyme)
Blocks mRNA synthesis by blocking RNA polymerase II.
456
Beta blockers also block the peripheral conversion of T4 to T3.
Repeat.
457
Which prokaryotic DNA polymerase is the ONLY one that can remove up to ten bases at a time by excising and replacing damaged RNA primers and DNA sequences?
DNA polymerase I (the less important one for replication).
458
What agar must Diphteria be grown on?
Cysteine-tellurite agar. The resultant colonies are black. The bacterium produces intracellular poly phosphate granules called metachromatic granules that can be detected on microscopy after methylene blue staining.
459
What organism grows on Thayer-Martin VCN media?
Neisseria.
460
Blood agar containing bile and hypertonic saline will grow which bacteria?
Enterococci
461
What type of bacteria tends to grow on MacConkey Agar?
Enteric bacteria especially Gram negative.
462
If you see a pathology slide of a hematology malignancy with only blasts and they have cytoplasmic inclusions, just pick AML regardless of the clinical presentation.
Repeat.
463
Mutation of a protein that normally interacts with the transferrin receptor and increases endocytosis of the iron-transferrin complex in enterocytes (and hepatocytes) is concerning for...(disease) (protein affected).
At risk for...
Hemochromatosis; HFE protein. Mutations in this protein cause enterocytes and hepatocytes to sense falsely low iron levels. Thus enterocytes in cells with the mutation respond by increasing uptake of iron through apical DMT-1 transporter and hepatocytes reduce their synthesis of hepcidin. This leads to iron overload.
At risk for hepatocellular carcinoma and liver cirrhosis.
464
Hepatic failure, encephalopathy, and vomiting in a child aged 5-14 who received ASPIRIN for fever is concerning for...
Histology:
Reye's syndrome -- usually in the setting of viral URI. LFTs will be elevated and PT, PTT will be prolonged.
Histology: Microvesicular steatosis WITHOUT inflammation or cerebral edema.
DO NOT give aspirin to kids under 16.
465
Gag reflex innervation:
Afferent limb - glossopharyngeal. Efferent limb - vagus.
466
Cough reflex
Vagus nerve - internal laryngeal limb governs afferent innervation above the vocal chords.
467
What cancer does chronic lymphedema predispose to?
Angiosarcoma. (Cutaneous, usually firm, violaceous nodules).
468
Myotonic dystrophy is autosomal dominant, and is cause by increased trinucleotide repeats of myotonia-kinase gene. Associated with frontal balding, gonadal atrophy.
Repeat.
469
An oxidase positive gram negative rod that produces a pigment on culture medium is concerning for
Pseudomonas infection. E.g. Hot tub folliculitis (papulopustular pruiritic rash).
470
How do timolol and other non selective beta blockers work in addressing glaucoma?
Timolol reduces synthesis of aqueous humor by the ciliary EPITHELIUM. Acetazolamide has a similar mechanism.
471
What is pilocarpine (and carbachol)? How do they work in glaucoma?
Pilocarpine is a cholinomimetic. It works by INCREASING OUTFLOW of aqueous humor in glaucoma. Prostaglandin F2 alpha like Lanaprost also INCREASE OUTFLOW of aqueous humor in glaucoma.
472
What disease does HiB classically cause in children in the absence of vaccination?
Meningitis, Pneumonia, Epiglottitis, Sepsis
All the other upper respiratory (otitis, sinusitis) syndromes are due to NON-TYPEABLE Hemophilus.
473
What is the origin of the spleen? Is it a gut derivative?
No! The spleen originates from mesodermal dorsal mesentery.
474
Hypoxemia. What are the ONLY 2 causes of hypoxemia that are NOT associated with an increased A-a gradient? What is this normal A-a gradient?
Hypoventilation and high altitude.
| Normal A-a gradient is 10-15.
475
What is hypoxemia?
Decrease in arterial oxygen BELOW 80.
476
In what hematologic disorder is the TYROSINE kinase JAK-2-STAT mutated to always be active?
CHRONIC Myeloproliferative disease like polycythemia Vera, essential thrombocytosis, and primary myelofibrosis. V617F mutation. Phenylalanine is now replaced by valine leading to constitutive tyrosine kinase activity that is independent of cytokines.
Ruxolitinib is a JAK 2 inhibitor approved for treatment.
477
What is the difference between CGD (NADPH oxidase deficiency) and myeloperoxidase deficiency?
In CGD, some organisms (those that DO NOT produce catalase) can be killed because their own peroxide can serve as substrate for myeloperoxidase to make free radicals to kill them.
However in myeloperoxidase deficiency, no free radicals can be created so there is susceptibility to both catalase and non-catalase organisms.
478
Garlic odor on breath in the setting of poisoning is concerning for what agent?
What is the antidote?
Arsenic poisoning. Will also present with stomach pains, vomiting, delirium.
Antidote is Dimercaprol which replaces arsenic ions in sulfylhydryl groups of enzymes and facilitates their excretion.
479
What is deferoxamine used for?
Iron overdose/poisoning. It binds iron in the bloodstream and facilitates its urine excretion.
480
What poisoning is CaN2EDTA used for?
It is used for acute mercury and lead poisoning.
481
Where in fungi is ergosterol located?
The Fungus CELL MEMBRANE. This is NOT the same as the cell wall.
482
What is the ONLY fungal agent that inhibits glucan synthesis?
Caspofungin. Glucan is in the cell wall. Caspofungin inhibits glucan synthesis.
483
What mechanism of injury to the fungal cell membrane do Amphotericin B and Nystatin share in common?
They both bind ergosterol and create pores in the cell membrane.
484
Which antifungal agents inhibit ergosterol synthesis?
All of the Azoles.
485
What is the risk associated with breaking into/entering a hydatid cysts? What organism is responsible?
Tip: cyst in an Australian or New Zealander
Echinococcus. The risk is ANAPHYLACTIC shock. This is associated with spilling contents into the peritoneum. Preferred therapy is Albendazole or mebendazole.
486
Low pH and HIGH 2,3 BPG will promote _______ in a HbS carrying individual due to...
Sickling due to anoxia.
487
What heart failure drug has adverse effects affecting COLOR VISION, non specific GI symptoms and neurologic symptoms?
What is the biggest risk associated with this medication?
Digoxin
Arrhythmias (ventricular arrhythmias)
488
How can you distinguish SVC compression from brachiocephalic vein compression?
In SVC compression, BOTH sides of the face, neck, chest, and BOTH arms would be involved because the right and left brachiocephalic veins join to make SVC.
The R brachiocephalic vein is formed from the combination of the R subclavian and the R internal jugular.
489
What cells actually move substances in mucociliary clearance?
Ciliated cells
490
What does tetrodotoxin, the Japanese pufferfish toxin block?
It blocks influx of sodium and depolarization of the cell (the rise of the action potential). It binds to voltage gated sodium channels in nerve and cardiac tissue.
491
What is the pathophysiology of ACUTE rejection in kidney transplant. Know this cold!
In addition to calcineurin inhibitors given to prevent this, what therapy should be given in the setting of ACUTE rejection?
Host T-lymphocytes are sensitized against MHC of donor.
Corticosteroids
492
What are the ONLY class of medications I should try to use to address anti-cholinergic poisoning?
Physostigmine.
493
What is the nucleolus? What happens there?
The nucleolus is the site of RIBOSOME subunit maturation and assembly. This is where rRNA is transcribed by RNA polymerase I.
494
What must I check before placing someone on metformin?
| MUST KNOW
Serum creatinine! It is contraindicated in renal failure and any other condition that predisposes to lactic acidosis.
495
Pramipexole stimulates dopamine receptors as does bromocriptine, pergolide, and ropinirole
Repeat
496
An erythematous papules or plaque with central pallor is concerning for? Especially if evanescent.
wheal! -- allergy, urticaria, etc. histamine!
497
If a child has a very high fever, what is the first emergency treatment that should occur even BEFORE administering acetaminophen?
COLD BLANKETS or otherwise facilitate body heat loss as this is faster than anti-pyretics
498
What are the effects of buspirone? Where does it bind?
Buspirone has minimal hypnotic effect and NO sedating effect! euphoria etc. It is great for someone with prior history of anti-anxiety medication abuse.
It is a 5 HT1A selective agonist. It is ONLY useful in generalized anxiety disorder, not useful in any of the related family of anxiety disorders. It takes 2 weeks to begin effect and must be used continuously.
499
What is the equation for half-life?
Vd (volume of distribution) x 0.7/clearance
500
What is the maintenance dose?
Maintenance dose =
steady state plasma concentration x clearance/(bioavailability fraction)
Bioavailability fraction = 1 for IV drugs.
501
What is loading dose?
Loading dose =
| Volume of distribution x steady state plasma concentration/(bioavailability fraction)
502
The longer that it takes a gas anesthetic to build up in the blood, the more SOLUBLE it is in the blood. This means it will take EVEN MORE time (and a larger amount of anesthetic) than usual to build up the partial pressure in the blood which has to meet its partial pressure in gaseous form. These anesthetics are said to have a higher BLOOD/GAS PARTITION COEFFICIENT. The higher the BLOOD/GAS PARTITION COEFFICIENT, the slower the onset of action and the slower the equilibration with the brain.
Repeat
503
What is the biggest effect of anthracyclines like doxorubicin and related drugs on the heart?
DILATED cardiomyopathy. Achieved by forming free radicals in the myocardium. This can lead to both right and left sided symptoms of heart failure.
504
What is vitamin B2? What does its deficiency present as?
Riboflavin.
It's deficiency presents as cheilosis, stomatitis, glossitis, dermatitis, corneal vascularization, and ariboflavinosis.
505
Think of the anatomic location of the mammillary body as almost an extension forward near the midbrain. It is close to the hypothalamus. Far down from corpus callosum.
Repeat
506
What is the maximum/min pressure in the right ventricle?
| Pulmonary artery?
Right ventricle min - 4mmHg and max is 25mmHg
Pulmonary artery min - 9mmHg, max is 25mmHg
Minimum in right atrium is 0. Max is 8mmHg.
Left ventricle minimum is 9mmHg and max is 130mmHg
507
What is the order of dissection in cricothyrotomy?
Superficial cervical fascia, pre tracheal fascia, cricothyroid membrane
508
Where is thyroid hormone's receptor located????
It is in the NUCLEUS!!!
PPAR and retinoids also have nuclear receptors.
509
What type of virus is parvovirus?
It's a non-enveloped single stranded DNA virus!
510
How does ribavarin exert its effect?
It interferes with the DUPLICATION of VIRAL genetic material
511
COX-2 inhibitors are preferred over NSAIDs becaus they have
No effect in platelet aggregation and cause little GI irritation.
512
Who is appropriate to OBTAIN informed consent?
The person performing the procedure.
513
Increased MAP, increased venous return, and increased cardiac output can occur from a
Chronic A-V fistula.
514
A vaccine directed against the pili of meningococcus must prevent what
Adhererence to epithelium/mucosa in the nasopharynx or nasal colonization which would lead to invasion
515
Organophosphates stimulate both muscarinic and Nicotinic cholinergic receptors because the IRREVERSIBLY inhibit AChE. What medication only reverts their muscarinic effects? What medication reverts their muscarinic and Nicotinic effects? What are the implications?
Atropine only addresses their muscarinic effects.
Pralidoxime addresses their muscarinic and Nicotinic effects. The implications are that reverting organophosphate cholinergic poisoning with atropine still makes an individual susceptible to muscle paralysis. Pralidoxime works by restoring AChE from its bond with Organophosphates.
516
In what reactions are transketolase present?
Transketolase is an enzyme in the pentose phosphate pathway. The entire pentose phosphate pathway occurs in the cytosol.
Pyruvate carboxylate, HMG CoA, beta oxidation of fatty acids, ketogenesis, parts of the urea cycle all occur in the mitochondria.
517
A yeast with germ tubes at 37 degrees is? Where did it most likely originate if found in sputum?
Candida. Most likely originated in oral cavity.
518
An individual who substitutes imaginary scenarios less disturbing (even if about the future alternate possibility in setting of poor diagnosis) is using what defense mechanism?
fantasy.
519
What anti-viral drugs do not depend on a viral kinase to be phosphorylated?
Cidofovir and Tenofovir (these drugs are nucleotides as opposed to nucleosides so they rely on a host cell kinase to be phosphorylated).
Zidovudine and Lamivudine are CELL-DEPENDENT nucleosides.
All other anti-virals like acyclovir, Ganciclovir, valacyclovir, and famiciclovir require viral kinase.
520
Which symptom of hyperthyroidism is usually NOT improved by beta blocker therapy?
Exophthalmos - it is due or increased soft tissue mass within the bony orbit which results from enlargement of extra ocular muscles and increased fibroblast proliferation and ground substance production.
521
How does insulin exert its effect in the liver?
It acts through a tyrosine kinase that stimulates a protein phosphatase that dephosphorylates glycogen synthase (activating it) and dephosphorylates fructose 1,6 bisphosphatase (INactivating it).
522
What is the mechanism of action of metyrapone?
Metyrapone blocks the production of cortisol in the adrenal gland by blocking 11 beta hydroxylase. In an individual with a healthy HPA axis, this leads to a reflexive increase in ACTH which leads to increased 11 deoxycorticosterone and increased urinary 17 hydroxy corticosteroid.
523
What other major class of drugs besides doxycycline can be used to treat Lyme?
Any Penicillin type antibiotic including ceftriaxone.
524
What is the mechanism of action of varenicline?
It is a PARTIAL AGONIST of nicotinic ACh receptor. It reduces cravings for nicotine and reduces reward associated with taking nicotine substance.
525
What portion of the duodenum can get compressed in SMA syndrome between the SMA and the aorta?
The TRANSVERSE portion of the duodenum. Anything that results in decreased mesenteric fat like weight loss etc can result in this clinical presentation where it seems like the patient has an SBO with bilious emesis.
526
What is reverse T3?
It is an inactive form of T3 generated entirely by peripheral conversion of T4 to T3.
527
What 2 drugs inhibit T cell growth and differentiation by inhibiting calcineurin?
Tacrolimus and cyclosporine
528
What cytokine triggers neutrophil chemotaxis?
IL-8.
529
Besides influenza, what other virus is segmented?
Rotavirus
530
What is IL-2 secreted by?
What does it stimulate?
In the case of malignant melanoma and Renal cell adenocarcinoma, what is its effect?
IL-2 is secreted by T helper cells and stimulates CD4, CD8, NK cells and B-cells.
In malignant melanoma and renal cell carcinoma, it is the increases NK cell activity that is thought to be effective.
531
What class of drugs are sedative hypnotics with anxiolytic, muscle relaxant, and anti-convulsants actions?
Benzodiazepines - increase frequency if Chloride channel opening.
532
What is the drug of choice to revert toxicity from a beta-blocker that will show up as hypotension and bradycardia?
How does it work?
Glucagon - G-protein coupled mechanism that activates adenylyl cyclase and upregulates cAMP in cardiac myocytes. This releases calcium from intracellular stores and causes increased SA node firing.
533
For someone who is always hungry, always looking for food, the LESION is in the ... (Which Hypothalamic nucleus)
Satiety center (ventromedial nucleus)
534
Anterior hypothalamic nucleus keeps me cool by stimulating the Parasympathetic system.
The posterior Nucleus of the hypothalamus keeps things hot.
Repeat.
535
What is the drug that can be used to treat RSV in an infant?
Ribavarin
536
What contributes to insulin resistance in overweight individuals?
High free fatty acids and high triglycerides.
537
Submandibular and sublingual glands are innervated by:
Facial nerve
538
What drug prevents nephrotoxic damage associated with cisplatin (cisplatin generates reactive oxygen species to damage DNA)?
Amifostine.
539
What are the two most common side effects of nitroglycerin and isosorbide dinitrate?
Headaches and cutaneous flushing. These occur due to the vasodilatory effects that occur if they are used at a high concentration.
540
What is the mechanism of action of bupropion?
It inhibits reuptake of NE and dopamine
541
What effect do beta blockers have in the kidney?
They block release of renin from juxta glomerular cells
542
Chlamydia has no peptidoglycan in its cell wall and that is why it is not susceptible to ceftriaxone. It does however contain Pencillin binding proteins. Ureaplasma urealyticum lacks a cell wall completely. Macrolides and tetracyclines are best for these.
Repeat
543
What is the only thing that must be supplemented after a patient undergoes a total gastrectomy?
Vitamin B12. Everything else does not need supplementation including proteins which can be broken down by pancreatic and intestinal proteases.
544
Hypersensitivity to ionizing radiation (High rate of radiation-induced genetic mutation, recurrent respiratory infections, and difficulty walking) are suggestive of...
Ataxia-telangiectasias. Autosomal recessive. Problems in DNA repair enzymes. Cerebellar atrophy can be seen.
545
What genetic disease is characterized by hypersensitivity of DNA to cross-linking agents?
Fanconi anemia.
546
If a patient has had several hospitalizations in one year, the most impart at issue even if smoking cessation is an option is to get
Advance directive/end of life care wishes.
547
Insulin beta cell secretion influencers:
| Autonomic nervous system:
Parasympathetic system stimulates muscarinic M3 receptors to promote insulin secretion (Gq)
Sympathetic nervous system: alpha 2 adrenergic receptors INHIBIT insulin secretion (Gi), Beta 2 adrenergic receptors STIMULATE insulin secretion (Gs)
548
What substance in packed red blood cells chelates the calcium and magnesium?
Citrate
549
If a patient given an opioid suddenly experiences right upper quadrant pain, what is happening? What cell type is involved?
Smooth muscle constriction of the Sphincter of Oddi that blocks the common bile duct and is a painful crisis known as opioid-induced biliary colic.
550
Hepatitis A can be destroyed by
Boiling for 1 minute to 85 degrees Celsius
Formalin
Bleach, chlorination
551
What endothelium-derived relaxation factor do muscarinic agonists promote the release of?
Nitrous oxide (EDRF). Nitrous oxide is present on the endothelial cell surface not the wall of the peripheral blood vessels. It increases cGMP (through guanylate cyclase) and activates Ca2+ EFFLUX from the cell promoting vasodilation.
552
A drug that promotes vasodilation and venodilation and promotes diuresis is _____. It is used it heart failure. It is an analog of ____
Nesiritide. Used in heart failure. Analog of BNP.
Both ANP and BNP decrease preload and activate guanylate cyclase to increase intracellular cGMP.
553
What pituitary hormone shares a common origin with endogenous opioids that target mu and delta receptors?
ACTH. Shared origin: POMC.
554
What is the pathogenesis of beta thalassemia?
Mutations in transcription, translation, and processing of beta-glob in gene. I.e. mRNA processing. Aberrant splicing or premature chain termination is most common.
555
What drug that can bind viral DNA polymerase (herpesvirus) and reverse transcriptase (HIV) does NOT require intracellular activation by viral or cellular kinases to have its effect?
Foscarnet - pyro phosphate analog.
556
What is the effect of ARBs on the RAAS system?
They block Angiotensin II's stimulation of its AT-1 receptors.
They thus increase Renin, Angiotensin I, Angiotensin II. Have NO effect bradykinin due to no effect on ACE. And reduce aldosterone levels.
Note ACE BREAKS DOWN bradykinin.
557
What is the initial abnormality in Paget's disease of the bone?
Increased osteoCLAST activity.
558
What lymph nodes receive drainage from the:
Scrotum
Testes
Glans penis
Testes - para-aortic lymph nodes
Scrotum - superficial inguinal nodes
Glans penis - deep inguinal nodes. The deep inguinal nodes also revive drain image from the superficial inguinal nodes.
559
Palpitations that are particularly prominent at night, head pounding with moderate exertion and involuntary head bobbing is likely due to...
Aortic regurgitation.
560
What drug is a narrow spectrum anticonvulsant that is also used for benign essential tremor and is metabolized to phenobarbital and other metabolites (phenylethylmalonide)?
Its toxicity presents as marked sedation.
Primidone
561
HIV drugs. Drugs that end in -navir are...
Protease inhibitors. They block proteolytic processing of viral enzymes that have been translated.
562
HIV Drugs. What is raltegravir?
It is an Integrase inhibitor.
563
What does Enfurvirtide do?
It prevents penetration of HIV into the cell. It blocks entry.
564
HIV drugs
| NNRTI's (non-nucleoside)
Nevirapine
Efavirenz
Delavirdine
565
Intracranial hypertension, dry skin (skin changes), and hepatosplenomegaly are concerning for...
Vit A excess.
566
What is associated with Vit E excess?
Hemorrhagic strokes in adults. Necrotizing enterocolitis in children.
567
Cheilosis, glossitis, CORNEAL vascularization, dermatitis, stomatitis, and ariboflavinosis is associated with...
Riboflavin deficiency
568
Why does human placental lactogen do?
It increases insulin resistance, stimulates proteolysis and lipolysis but inhibits gluconeogenesis.
569
How does acyclovir work?
It is best against VSV/HSV. It works by acting as a guanosine analog. It is mono phosphorylated by VZV/HSV Thymidine kinase and then a triphosphate is formed by cellular enzymes. It selectively preferentially inhibits viral DNA polymerase by chain termination.
570
What molecule is an important activator of gluconeogenesis?
AcetylcoA. It is a potent activator of Pyruvate carboxylate which converts Pyruvate to oxaloacetate. Then malate dehydrogenase converts oxaloacetate to malate. Malate is then shuttled out of the mitochondria where it is then converted back to malate by malate dehydrogenase. Finally, cytosolic oxaloacetate is converted to PEP with PEP carboxykinase.
571
Lymph node drainage
Anus -
prostate -
Bladder -
Anus - (below the dentate line) - superficial inguinal
Prostate - internal iliac nodes
Bladder - superior portion (external iliac nodes), inferior portion (internal iliac nodes).
572
What does an AV shunt do to preload? To afterload? Which of the following then changes: ESV or EDV?
AV shunt increases preload and DECREASES afterload. The biggest change is observed in EDV (end diastolic volume).
573
What is phenoxybenxamine?
An irreversible alpha 1 and alpha 2 antagonist.
574
Phenotalamine?
Phentolamine is a REVERSIBLE competitive alpha antagonist.
575
How do diabetic drugs canaglifozin and dapaglifozine work? What should be monitored before initiation?
They inhibit proximal tubule glucose resorption (SGLT2). Creatinine should be monitored before initiating.
576
Measles and rubella presentation can be very similar. One of the physical finishing to distinguish them is post auricular and occipital lymphadenopathy. Which is this sign consistent with?
Rubella (Togavirus)
577
Where is the posterior urethra located which is often injured when there is pelvic trauma and full bladder sensation, high riding prostate?
It is injured at the level of the prostatic urethra or membranous urethra which is by the bulbourethral glands above the urethral spinchter.
Everything beyond the urethral sphincter to the exit is considered ANTERIOR urethra.
578
When supine, where do most patients usually aspirate?
Posterior segment of upper lobes and superior segment of lower lobes.
If patients, on the other hand are upright, basilar segments are most likely.
579
What is the correlate of myxomatous changes in the media of large arteries?
Cystic medial degeneration (e.g Marfan's syndrome - aortic aneurysm)
580
What is the drug of choice for hirstutism in a woman?
Spironolactone for it's anti-androgen effects. Can also use flutamide (anti-testosterone receptor) and finasteride.
581
Which of the monosaccharides is metabolized the quickest?
Fructose. It is phosphorylated to Fructose-1-phosphate and then bypasses PFK-1 to become the major rate limiting enzyme of glycolysis. Other sugars enter glycolysis before PFK-1.
582
Fatty acid oxidation CONSUMES more oxygen than other forms of oxidation yet is the main form of metabolism carried out in the heart. It is thought that use fatty acid inhibitors can help with angina because they shift metabolism towards glycolysis and glucose oxidation which generate less ATP than fatty acid oxidation but require less oxygen.
Repeat
583
When treating infertility due to anovulation ____________ (pharmacologic agents) act like FSH while a shot of hCG acts as ___
Menotropins act like FSH.
hCG acts like LH.
584
What portion of the heart supplies the diaphragmatic surface of the heart? What is its blood supply?
Diaphragmatic surface of the heart is supplied by inferior wall of the LEFT ventricle which is supplied by the PDA.
585
So Long to (Triquetrum) Pinky Here Comes the Thumb
Repeat. Carpal bones in hand.
586
A patient with Mycoplasma pneumoniae demonstrates signs of mild anemia and elevated LDH, what is happening?
Pt is having mild hemolytic anemia due to the similarities of Mycoplasma's phospholipid membrane (recall it has no cell wall) and our erythrocytes. When an immune response is mounted against mycoplasma by COLD AGGLUTININS, there is also some lysis of our RBCs.
587
If a patient with an MI (and history of asthma) is treated for acute coronary syndrome and then all of a sudden becomes short of breath, what might have happened?
Beta blocker causing bronchoconstriction.
588
How does zidovudine exert its effect?
AZT (zidovudine) is a NRTI. It is phosphorylated by a HOST KINASE and blocks 3'-5' phosphodiesterase bond formation by not having a -OH group on its 3' end. It is incorporated as a THYMIDINE analog.
589
What is the gastrocolic ligament?
The lesser omentum has the full length of the stomach hepatogastric ligament and hepatoduodenal ligament.
Gastrocolic ligament is the part of the greater omentum that connects stomach to transverse colon.
590
What are the histologic changes that occur in response to increased ACTH production in Cushing disease from the pituitary?
What about if it is ectopic CUSHING (e.g. Adrenal adenoma or carcinoma)
Central Cushing induced by ACTH production leads to hyperPLASIA not hypertrophy of the Fasciculate and reticularis layers.
Ectopic ACTH production leads to atrophy.
591
Skin infection, and pneumonia in a neutropenic patient is concerning for...
Ecthyma gangrenosum. Pseudomonas infection.
592
A HIV drug that blocks gp41 probably blocks which of the following? Viral attachment or viral penetration?
Viral penetration. This drug is Enfurvirtide. GP 41 assists with penetration/fusion of the virus into the cell.
A drug that inhibits attachment has to inhibit gp120.
593
What are the possible conversions for excess glucose that makes it to the LENS of the eye.
Glucose to SORBITOL. (Performed by ALDOSE reductase)
SORBITOL to fructose. (Performed by sorbitold dehydrogenase). Overwhelmed in diabetes so most of the glucose stays as sorbitol.
594
Retinitis in a patient with HIV with CD4 count under 50 is usually due to _____ (viral agent). Treat with ______.
Viral agent: CMV.
| Treat with Ganciclovir
595
What signal is the major proliferative stimulus for artherosclerotic plaques that form?
PDGF - platelet derived growth factor.
596
Treat ANY partial seizure with:
Carbamazepine
597
A young teenage boy who wakes up with arrhythmic muscle contractions and has a family history of seizure disorder has...
Treat with
Myoclonic seizures.
Treat with: valproic acid. It suppresses abnormal electrical activity in the cortex by affecting GABA and NMDA receptors as well as Na+ and K+.
598
What is the treatment for idiopathic pulmonary hypertension?
How does it work?
Bosentan
Competitive ANTAGONIST of ENDOTHELIN RECEPTORS.
Pathology: medial hypertrophy and intimal fibrosis.
599
What is the most common cause of death from TCA toxicity?
TCAs work by inhibiting serotonin and NE reuptake BUT death is due to cardiac arrhythmias. It is inhibition of the FAST sodium channels in cardiac myocytes leading to prolongation of the QRS that causes death. The treatment is normal saline and hypertonic bicarbonate.
The peripheral vasodilatation seen in their toxicity is due to their alpha 1 adrenergic effects.
600
What is the first line treatment for ACUTE gout no matter what:
NSAIDs (COX inhibitors).
Colchicine is a second line agent due to its nausea, diarrhea effects.
Only use glucocorticoids in patients for whom both NSAIDs and colchicine are contraindicated.
601
Hypoglycemia, keto acidosis, hepatomegaly, in a young child is concerning for....
Glycogen debranching enzyme deficiency.
602
Hepatic steatosis, hypoglycemia, LACTIC ACIDOSIS, Hyperlipidemia and hyperuricemia is concerning for...
Glucose 6 phosphatase deficiency.
603
How does Pyruvate kinase deficiency present?
Hemolytic anemia because Pyruvate kinase normally turns PEP to Pyruvate and when it is missing, there is no source of energy for erythrocytes which can only undergo glycolysis.
604
Mycobacterium that does NOT express catalase-PEROXIDASE or genetically modifies the binding site of this drug in the mycolic acid synthesis pathway can develop resistance. What is the drug?
Isoniazid.
605
To kill P vivax or P ovale schizonts use:
Primaquine
606
Biggest concerns in lightning:
Cardiac arrhythmia
Respiratory failure
607
If a patient vomits following chemotherapy, what region of their brain has been affected.
The area postrema. Which is in the chemotherapy trigger zone located on the DORSAL MEDULLA OF THE FOURTH VENTRICLE.
608
Dilatation of the left ventricle (dilated cardiomyopathy) impairs __________
Hypertrophy of the left ventricle impairs ___________
Dilated cardiomyopathy or dilatation of the left ventricle impairs CONTRACTILE FUNCTION
While hypertrophy of the left ventricle impairs FILLING.
609
What is meperidine?
It is an OPIOID mu agonist! As far as I am concerned, mepiridine is like morphine but has anti-cholinergic effects.
Another opioid is levorphanol! Same mechanism.
610
What drug is an opioid mu partial agonist and antagonist that might lead to withdrawal symptoms if given with an opioid?
Pentazocine
611
If a cross section of spinal cord is shown, look for the ventral horn at the sides. If it is there, you are at the thoracic level due to the Sympathetics!
Dorsal nerve roots that are like coming off the cord mean you in lumbar or sacral area.
Repeat
612
Heavy calcification of a valve that is the precursor of aortic sclerosis actually signifies necrosis of cells.
Repeat
613
What is the effect of high affinity hemoglobins?
They cause renal hypoxia which leads to erythrocytosis.
614
Where does the median nerve course
Between flexor digitorum superficialis and flexor digitorum profundus. Before this, the median nerve courses between the humeral and ulnar heads of Pronator teres.
615
What type of renal stone does the cyanide sodium nitroprusside test detect? The urine becomes red-purple in color.
Cystine. Hexagonal crystals. Problem with Renal PCT absorption of cysteine.
616
Sterile, small non-destructive cardiac vegetations are classic for...
Non-bacterial thrombotic endocarditis. There is a bland thrombus with no inflammation. This reflects a HYPERCOAGULABLE state as is seen in Trousseau syndrome. If associated with cancer it is called Marantic endocarditis.
617
Inhaled anesthetic like halothane can cause a FULMINANT hepatitis that is non-distinguishable from viral hepatitis. The result is prolonged prothrombin time and high LFTs. The trick is the shrunken liver on autopsy. Prothrombin is first affected due to short half life of Factor VII.
Repeat.
618
What famous enzyme is 72kD and only present in the setting of inflammation in most tissues?
What drug inhibits it?
COX 2
Aspirin
619
Microtubules ALSO are considered to contribute to the cytoskeleton.
Repeat.
620
What is most common sequelae of Rubella in a pregnant mom and in her unborn fetus.
Mom - polyarthralgia
Fetus - sensorineural deafness.
621
What is the PREFERRED treatment for carcinoid syndrome?
Octreotide
622
If someone with Parkinson's is frustrated with the on/off nature of symptoms when on levodopa, explain that DRUG response is UNPREDICTABLE. Thought to be progressive nigrostriatal degeneration.
Repeat
623
What toxin is Diphteria toxin similar to?
Pseudomonas toxin (Exotoxin A) which also inhibits EF2 and thereby blocks protein synthesis.
624
What is the mechanism of C.diff's toxin?
It induces actin depolymerization leading to mucosal death and pseudo membrane formation.
625
Where is the (GREAT) saphenous vein harvested?
Just infero-LATERAL to the public tubercle. It does NOT go through the adductor canal.
626
What is ethosuximide's mechanism of action?
It blocks T-type Ca2+ in thalamus neurons. This is how it works for absence seizures.
627
What is the mechanism of action of carbamezepine?
What is a major adverse effect?
It blocks VOLTAGE-GATED sodium channels.
Risk: bone marrow suppression so Review blood counts often.
628
Which bacteria disinhibits G-inhibitory (Gi) ADP ribosylation that presents with a cough in kids?
Bordetella pertussis. It thereby increases intracellular cAMP. Causing histamine sensitivity and phagocyte dysfunction.
629
What pharmcologic agent is similar to Vit B6 (pyridoxine) and inhibits the saturation of long branched lipids in some bacterial cells?
Isoniazid
630
An old liquefactive necrosis scar in the brain is still surrounded by what cell type:
ASTROCYTES.
631
First arch syndrome where there can be malformation of the mandible is also associated with malformation of:
What is the innervation:
Malformation of malleus, incus, maxilla, zygoma, vomar, palate, temporal bone.
Associated nerve is trigeminal nerve.
632
What is an ABNORMALLY prominent v wave suggestive of in the setting of heart failure,
Mitral regurgitation.
633
Monomeric analysis of Hb subunits yields a curve similar to that of myoglobin.
Repeat.
634
The diarrhea seen in shigellosis is MOST due to...
The MUCOSAL INVASION of shigella through the M cells of the Peyer's patches after which it escapes the phagosome and then spreads laterally to other cells. It is only after this that it releases its toxin. The mucosal invasion is the key issue.
635
What does oseltamivir block?
Viral release!
636
What is the treatment of choice for mucormycosis?
What are its side effects
Amphotericin B. Adverse effects: Nephrotoxicity. SEVERE HYPOKALEMIA AND HYPOMAGNESIA OFTEN REQUIRING DAILY SUPPLEMENTATION. This is due to increased DCT permeability.
637
Which class of anti-arrthymic drugs exhibit use dependent prolongation of the QRS interval at faster heart rates?
Class IC. They are potent FAST sodium channel blockers. Meaning they affect phase zero and block the INWARD sodium current. E.g. Flecainide.
This is as opposed to the Class III anti-arrhythmics which exhibit reverse use prolongation where the QT interval is prolonged the slower the heart rate and they ONLY prolong the QT interval.
638
What is the most likely cause of death in the setting of Strep pneumoniae infection?
Myocarditis--pancarditis that can be associated with a functional Mitral regirgitation! It has nothing to do with the renal failure. Kids usually recover from the renal failure.
639
What type of drugs are more preferentially processed by the liver?
Drugs that are very lipophilic, high volume of distribution, good penetration into the CNS are preferentially processed by the liver into more polar compounds for easier elimination in the bile and in the urine.
640
Cefepime is effective against pseudomonas.
Repeat.
641
How does TNF-alpha induce insulin resistance?
Aberrant Phosphorylation of serine or Threonine residues of Insulin Receptor Substrates by SERINE KINASE. Catecholamines, glucagon, and glucocorticoids produce Insulin resistance by same mechanism.
642
In atrial fibrillation, it is the AV node refractory period that determines the ventricular rate.
Repeat
643
What are transpeptidases?
They ARE a type of Pencillin binding protein and are the target of cephalosporins and Pencillins.
644
What nerves carry the sensation of PAIN in the tongue?
The lingual nerve of the V3 branch of the trigeminal nerve carries pain for the anterior 2/3 of the tongue.
The glossopharyngeal nerve carries pain for posterior 1/3.
The vagus does not carry taste at all for the tongue. It carries taste signals from the pharynx and epiglottis and innervates palatoglossus
645
How do Thiazolidendiones work?
They DECREASE INSULIN RESISTANCE. They upregulate PPAR-gamma which leads to INCREASED ADIPONECTIN, INCREASED GLUT-4 transporter, increased fatty acid transport protein, increased insulin receptor substrate. Adiponectin is a cytokine normally secreted by fat cells. It's levels are usually low in Type 2 diabetes but TZD's increase its level. Due to their nuclear mechanism of action, TZD's take SEVERAL WEEKS to have effect. Also note, TZD's DO NOT CAUSE HYPOGLYCEMIA. Their adverse effects are weight gain and fluid retention that can lead to CHF.
646
How does elastin acquire its ability to recoil?
Elastin's plasticity relies on desmosine crosslinking between four different Lysine residues on 4 different elastin chains that is done by LYSYL HYDROXYLASE. Big picture: LYSINE interchain crosslinks. There is minimal proline and Lysine residue hydroxylation in elastin as opposed to collagen.
647
What artery is at risk in femoral neck fracture?
Medial circumflex artery.
648
If blood vessels are in PARALLEL, what is the equation for resistance?
1/R(Total) = 1/R1 + 1/R2 etc.
DO NOT forget the sum = 1/R(total)
649
What are the factors that contribute to the pathophysiology of acne in the 20s?
1. ANDROGENS
2. Follicular epidermal hyperplasia
3. Sebum production
4. Inflammation
5. P.acnes
650
What are some common hormones that stimulate Gs, adenylate cyclase pathway?
Glucagon, TSH, PTH.
651
Cutaneous, rubbery lesions, and a headache in the setting of several pigment spots on someone's back are concerning for ....
What is the embryologic cell of origin?
NF-1. Neural crest cells. Recall NF-1 is associated with gliomas.
652
What does neuroectoderm give rise to?
The CNS and All it's cell types.
653
Myoglobin rich, glycogen poor fibers in muscle suggests they are which type of fibers?
Which muscles tend to have these?
Type I slow twitch, RED fibers. These fibers get energy primarily from oxidative phosphorylation. Usually found in postural muscles like para spinal muscles and erector spinae.
654
Which type of muscle fibers are then packed full of glycogen and derive energy from glycogenolysis and glycolysis?
Type IIB fibers.
Both of the Type II muscle fibers are considered fast twitch but type IIa fibers share proprieties of both slow and fast fibers in terms of preferred route of metabolism to create ATP.
655
Only what organ can use glycerol produced by the degradation of triglycerides for triacylglycerol synthesis, gluconeogenesis, and as an intermediate in glycolysis. What is the organ? What enzyme is specific to it?
Liver. Glycerol kinase.
656
What does acetylCoA carboxylase do?
It makes malonyl CoA from acetyl CoA as the first COMMITTED step in the fatty acid SYNTHESIS. Fatty acid synthesis occurs exclusively in the cytosol as opposed to beta-oxidation which occurs in the mitochondria.
657
Cancer cells that demonstrate multi-drug resistance are expressing...
Human multi drug resistance gene 1 (MDR1) that codes for P-GLYCOPROTEIN which is a transmembrane ATP dependent efflux pump for hydrophobic compounds. It reduces influx of chemotherapy drugs and can increase efflux of these substances as well.
658
While most ALL in kids is from B-cells, how do T-cell ALL present?
Mediastinal mass that can cause respiratory symptoms, dysphagia and SVC syndrome.
659
Part of the reason it is difficult to develop a vaccine against gonococcus is because it keeps VARYING its PILUS PROTEIN.
Repeat
660
What do theca externa cells do as opposed to their LH sensitive, androgen making theca interna counterparts?
Theca externa is the connective tissue support structure for the developing follicle.
661
The vegetations on valves in bacterial endocarditis DO NOT actual infection. They represent...
Fibrin and platelet deposition at a site of bacterial colonization.
662
How does verapamil act on the AV and SA nodal cells?
It slows their diastolic depolarization because the last part of phase 4 after the slow inward sodium current is a transient inward calcium current that augments the nodal cell depolarization. They also obviously reduce the calcium current in phase zero.
663
What mechanism does MRSA use to evade all beta-lactams including beta-Lactamase resistant antibiotics like methicillin?
It CHANGED its Pencillin binding proteins.
664
Hepatocytes with cytoplasm that is filled with spheres and tubules that take on a finely granular, eosinophilic appearance commonly described as ground glass are suggestive of what infection?
What protein is present in the granules?
Hep B infection.
HepBSAg in the granules.
665
In the setting of acute PHYSIOLOGIC STRESS, like burns or trauma or INCREASED INTRACRANIAL PRESSURE, ULCERS THAT OCCUR are due to
Stress related mucosal erosions that can occur in the setting of acute stress and are at increased risk for perforation. Once the stress is removed, these mucosal erosions resolve.
666
How is the rapid relaxation of cardiac muscle achieved in myocyte excitation-contraction coupling?
It is achieved by the Na/Ca2+ exchanger which accepts 3 sodium for one Ca2+ and the Ca2+ ATPase pump on the SR. Note the ATPase pump on the SR is not the same as the Ryanodine receptor.
667
What kind of overload is the left ventricle subject to in aortic regurgitation? Pressure or volume overload? What kind of cardiomyopathy would then be expected?
In the setting of acute aortic regurgitation, what is the adaptation of the heart?
Aortic regurgitation subjects the LV to VOLUME OVERLOAD. That means that there is a dilated cardiomyopathy (eccentric) and the sarcomeres are in the series.
The adaptation to Aortic regurgitation is an INCREASE in PRELOAD. While there may be a transient increase in heart rate immediately on developing AR, the heart rate returns to normal levels because increase in preload effectively restores cardiac output.
668
How does clopidogrel work?
It IRREVERSIBLY inhibits binding of ADP to platelet surface receptor thereby blocking PLATELET AGGREGATION.
669
Where is the cardiac action potential conduction velocity the slowest? Where is it the fastest?
The mnemonic is Park At Ventura Ave from Fastest to slowest. Purkinje fibers, Atrial muscle, ventricular muscle, AV node. AV node is the slowest at conduction because it is designed to give the ventricles time to fill.
670
Early signs of Coagulative necrosis or signs of ischemia take 4 hrs to develop after an MI. For the first 4hrs, the cardiac tissue looks normal.
Repeat.
671
What type of drug is pilocarpine?
What about scopolamine?
Which would you want to use to combat the effects of someone experiencing and excess of acetylcholine? I.e. Which is anti cholinergic?
Scopolamine is anti cholinergic. Specifically, it only has anti-cholinergic effect at muscarinic receptors. To address a cholinergic overload situation, you want to use scopolamine. The nice thing is it will not affect any desires cholinergic effect in Nicotinic receptors like in the setting of treating myasthenia gravis. Hyoscyamine is another drug with similar effects.
Pilocarpine is a choline mimetic.
672
When a PURE red cell aplasia is witnessed, what is the differential?
Inhibition of erythropoietic precursors or IMMUNE DESTRUCTION by IgG autoantibodies or T-cytotoxic lymphocytes. All pts with PRCA should get a CT of the chest because both thymomas and lymphocytic leukemia have been implicated. The other explanation is recent Parvovirus B19 infection.
673
When you are asked to calculate drug clearance, it is important to calculate half-life.
T 1/2 = (Vd x 0.7)/clearance rate.
674
The pathology correlate of rickets is...
Osteoid accumulation around trabeculae. I.e. Unmineralized osteoid and widened osteoid seams.
675
Persistent hiccups, shoulder pain, and Dyspnea on the setting of a lung cancer suggest irritation of what nerve?
Phrenic nerve. Dyspnea due to diaphragmatic paralysis. Hiccups due to phrenic nerve innervation.
676
Why is a patient with Crohn's ileocolitis predisposed to forming gallstones and what gallstone type do they form?
The terminal ileum is where bile acids are usually absorbed. These pts have INCREASED BILE ACID WASTING. That results in reduced bile acid to cholesterol ratio in the bile which leads to CHOLESTEROL PRECIPITATION and CHOLESTEROL GALLSTONES.
Bile acids are produced in liver, excreted in bile and form micelles with fat droplets that are resorbed in the terminal ileum where they return to liver. In Crohn's involving the terminal ileum, bile acids are instead excreted in feces.
677
How do left sided colon cancers present?
Right sided?
Right sided present with bleeding -- iron deficiency, weight loss. (Exophytic mass).
Left sided colon adenocarcinoma tend to infiltrate the wall and cause obstruction, constipation, change in stool caliber.
678
What is the major concern in theophylline toxicity or overdose?
SEIZURES! Along with a presentation usually of abdominal pain nausea, vomiting, diarrhea. Treat with benzos and barbiturates.
The second big concern is TACHYARRYTHMIAS which can be treated with beta blockers because there is usually no QT prolongation in theophylline toxicity.
1st priority in mgmt: GASTRIC LAVAGE followed by ADMINISTERING CHARCOAL TO REDUCE ABSORPTION AND CATHARTICS TO INCREASE GI excretion.
679
If a patient forms anti-histone bodies when placed on a drug, what is the likely mechanism?
This pt is pre-disposed to developing drug-induced lupus. They are likely on a drug that is metabolized by LIVER N-ACETYLATION. Two common drugs that fall into this category are procainamide and hydralazine. It is SLOW acetylators who are at risk and this risk is Genetically determined by their acetylation type. There is NO NEED TO STOP THE DRUG unless they develop frank clinical signs of lupus. Most pts on procainamide or hydralazine have positive ANA without developing symptoms.
680
A fungus that is in a spherule with endospores is concerning for...
Coccidioides immitis which exists in the environment as a hyphae (mold) but becomes spherule with endospores in us. It can infect IMMUNOCOMPETENT and IMMUNICOMPROMISED.
681
A patient with fever, abdominal pain, watery diarrhea or constipation, rose-colored or salmon-colored papules on chest and abdomen, hepatosplenomegaly is concerning for...
SALMONELLA THYPHI. These pts also often have a relative bradycardia compared or their temperature. Fecal-oral transmission.
Feared complications are hemorrhagic enteritis and PERORATION.
Salmonella THYPHI enters through the M cells of the Peyer's patches and survives and proliferates in the macrophages and then leads to bacteremia.
682
What causes mast cell degradation?
It is the CROSSLINKING of two IgE molecules bound to a single antigen not just a single IgE on the mast cell that binds the antigen. I.e. aggregation of IgE-Fc receptors on the mast cell surface that leads to degranulation.
683
What is the core pathophysiology of analyphlaxis?
What molecules are released by the most active cell type?
Massive MAST CELL DEGRANULATION.
Histamine, TRYPTASE, HEPARIN. Drug that prevents mast cell degranulation: Cromolyn sodium
Do not mix up a mast cell with an eosinophil. The job of an eosinophil is to CONTAIN MAST CELL degranulation. Thus, it has a histaminase and arylsulfatase and is extremely effective at PHAGOCYTOSING ANTIGEN-ANTIBODY COMPLEX.
684
What is the only form in which cryptococcus exists?
As a BUDDING YEAST. Treat it with Amphotericin B and Flucytosine. For lifelong prophylaxis, give a pt Fluconazole.
685
When in the action potential is the membrane most permeable to postassium?
During REPOLARIZATION MIDWAY of the way DOWN the curve.
Of note, on the other hand, SODIUM permeance is highest at the action potential PEAK.
686
What vitamin acts as a co-factor for cysthathione synthetase I'm the conversion of homocysteine to cysteine?
B6 (Pyridoxine)!
687
What vitamin acts as co-factor for methionine synthase in the conversion of homocysteine or methionine?
What is important to recall that EXCESS methionine can be converted back to?
Methyl-B12. I.e. Methyl cobalamin.
Excess methionine becomes homocysteine! This is why you RESTRICT METHIONINE in the diets of patients with homocysteine and SUPPLEMENT CYSTEINE AND B6 (pyridoxine) instead.
688
A budding yeast that also has occasional GERM TUBES (pseudohyphae) after being grown for 3 hours at 37C is...
Candida albicans
689
How do Rhizopus and mucor appear?
As a thick ribbon. Treatment: Amphotericin B.
690
What is the most common cause of congenital torticollis which shows up between 2 and 4 wks of age?
Causes: malposition of head in uterus or birth trauma.
Treatment: conservative therapy. Stretching exercises.
691
What is the status of TOTAL BODY POTASSIUM vs EXTRACELLULAR POTASSIUM IN Diabetic keto acidosis?
In DKA, Total body potassium which happens to be reflected by intracellular stores (98% of K+ is intracellular) is DECREASED.
While extracellular K+ is INCREASED.
692
What is the difference between unfractionated heparin and the LMWH (enoxaparin and fondaparinux) in terms of Xa and thrombin binding?
All of them work via anti-thrombin.
While all the heparins bind Xa effectively. Only UNFRACTIONATED HEPARIN IS ALSO LONG ENOUGH TO BIND THROMBIN.
693
What is the clinical course for most adults if they get an infection with Hep B?
Hep C?
Hep B - clear the acute infection
Hep C - stable chronic hepatitis. Cirrhosis is unlikely -- less than half develop it.
694
What sense RNA can be DIRECTLY TRANSLATED?
Positive-sense RNA = mRNA
695
What is unique about the extracellular fluid volume in SIADH?
It is normal!!!! Euvolemic hyponatremia. The total body water is INCREASED.
There is a transient subclinical volume expansion but that is quickly compensated by reduced aldosterone and increased natriuretic peptides which increase sodium excretion and restore ECF.
696
What vitamin is a cofactor for TRANSAMINATION reactions and can show up as a hypochromic, Microcytic, sideroblastic anemia that is responsive to repletion when this vitamin is deficient?
B6 (pyridoxine).
697
If a kid has Stridor, just seriously consider picking croup (paramyxovirus). There is usually a URI that precedes development of the cough.
Oh and RSV associated with Bronchiolitis is also a paramyxovirus. So pick this already. Sheesh.
Repeat.
698
What is the famous Togavirus?
Rubella!!!! Think, toga -- rash.
699
What do aminocaproic and Trinexamic acid do?
INHIBIT fibrinolysis. I.e. They make clots stay -- they can treat certain bleeding disorders usually those cause by an overdose of t-PA like substances.
700
Spoon-shaped or mishapened nails (Koilonychia) and dysphagia are both suggestive of what vitamin deficiency?
Iron!!!! The dysphagia is due to the formation of esophageal webs.
701
What is the most important side effect of a VAsodilator?
It will decrease renal perfusion leading to increased sodium and fluid retention!!!
It is not a transient hypertension. In fact, vasodilators lead to a compensatory response that primarily focused on restoring HR.
702
What is the primary effect of pulmonary edema?
It DECREASES LUNG COMPLIANCE and it INCREASES surface tension.
703
What is the biggest thing increased pCO2 like in the case of COPD will do?
It will cause cerebral vasodilation or decreased cerebral vascular resistance.
Note, that patients with COPD have increased PCO2 and reduced pH and reduced arterial and venous oxygen content.
704
What are two important viral and host cell antigen pairs to recall?
Parvcovirus B19 and erythrocyte P antigen
EBV gp350 and CD21 on B. Cells.
705
Osmotic diarrhea like that seen in lactose deficiency is associated with a HIGH STOOL OSMOLAR GAP.
Secretory diarrhea like that seen in cholera or VIPoma is associated with a LOW STOOL OSMOLAR GAP.
Equation: Stool OSMOLAR gap = 290 - 2* (Stool Na + Stool K)
Repeat.
706
Lactose deficiency is associated with a decreased stool pH, INCREASED Stool osmotic gap and increased breath hydrogen content.
Repeat.
707
Small CIRCULAR DNA obtained from one of our eukaryotic cells that has tRNA encoded and rRNA and proteins is ...
Mitochondrial DNA! Found in the mitochondria.
708
What are patients with obstructive sleep apnea at risk for?
PULMONARY hypertension AND right ventricular failure in addition to systemic hypertension.
709
If the hypothalamus is destroyed, what major hormone secreted by the pituitary will INCREASE?
Prolactin. Prolactin is under tonic inhibition from the hypothalamus by dopamine that is released from the hypothalamus and binds to D2 receptors on the lactotrophs.
710
Recall that the Histamine 1 receptor antagonists have prominent anti cholinergic effects that are responsible for symptoms like facial flushing and pupillary dilatation.
Repeat.
711
If TB in parallel chains or with serpentine cords, what does that imply?
It implies CORD FACTOR is present which is a VIRULENCE MARKER. In the absence of cord factor, TB cannot cause disease. Cord factor is responsible for neutrophil inhibition, mitochondrial destruction and release of TNF.
712
What does thyroid PEROXIDASE do?
It oxidizes iodide (I-) to iodine (I2), it iodinates the tyrosine molecules on THYROGLOBULIN this forms moniodotyrosine or dioodotyrosine molecules And COUPLES them previous ones already on TBG to make T3 and T4. Then the follicular cells takes up the TBG and lyses it in the lysosomes to release T3 and T4.
713
What is somatomedin C?
It is IGF-1!!!!
714
Periodic breathing (I.e. Cyclical variation in tidal volume) that seems to be responsive to PCO2 especially with PCO2 levels being the LOWEST at the beginning of the apneic episode are probably Cheyne Stokes breathing suggestive of heart failure or neurologic disease.
Repeat.
715
What is the less common equation for cardiac output?
Oxygen consumption/AV difference.
716
What are the major side effects of HIV protease inhibitors (-navir)?
Lipodystrophy
HYPERGLYCEMIA - these drugs increase INSULIN resistance.
INHIBIT Cytochrome P450. Because these drugs are also metabolized by cytochrome P450, they should never be mixed with Rifampin which will reduce the protease inhibitor levels. Instead, use Rifabutin for mycobacterial infection in the setting of HIV in a pt on a protease inhibitor.
717
Eosinophilic casts in the tubules of an elderly patient are concerning for...
Bence Jones -- multiple myeloma protein
718
While bile acids on their own are absorbed in the ileum, where are LIPIDS (triglycerides, cholesterol, phospholipids) digested? Where are they absorbed?
Digested in duodenum. Absorbed in JEJUNUM.
719
What common substance reduced %O2Sat?
What common poison INCREASES % O2Sat?
Carbon monoxide; competes with oxygen.
Cyanide increases O2 Sat of VENOUS BLOOD because it prevents oxygen unloading.
720
What is the best auscultation finding for assessing severity of MITRAL REGURGITATION?
presence of an S3 gallop. In severe MR this indicates increased rate of filling of the left ventricle.
721
What part of the long bones is usually affected in OSTEOMYELITIS?
Metaphysis because of slower blood flow and capillary fenestrations. Without proper treatment, risk is chronic suppurative osteomyelitis.
Treatment: antibiotics AND Debridement.
722
What famous class of drugs re-establish perfusion in the setting of ACUTE myocardial infarction and can be associated with REPERFUSION arrythmia?
T-Pa. Fibrinolytics.
723
How does Hep B predispose to increased risk of HCC?
It integrates its viral DNA into hepatocytes and can trigger neoplastic changes. Recall though that most adults with acute Hep B infection CLEAR it.
724
Alanine gives it amino group to alpha-ketoglutarate and forms _____ as a substrate for gluconeogenesis. The alpha-ketoglutarate that received the amine group is now GLUTAMATE.
Pyruvate.
The formed glutamate is processed in the liver to form urea and then is excreted via the kidneys!
725
Pancytopenia and NO splenomegaly suggest...
What would be seen in the bone marrow?
Aplastic anemia.
Hypocellular marrow filled with fat cells and stroma.
726
Double stranded circular DNA associated with reverse transcriptase and atypical lymphocytes is concerning for what common infection?
Hep B infection.
727
Spider angiomas BLANCH and look like spiders!!!
Repeat
728
What type of angiomas are associated with aging starting from 30yrs of age?
Cherry hemangiomas. Common benign vascular lesion. On light microscopy show proliferation of capillaries and post-capillary venules in papillary dermis.
729
What are superficial hemangiomas?
They are the SAME as the infantile hemangiomas.
730
What is responsible for the rise just after the sloping rise of the funny current in nodal cells?
Ca2. This corresponds to phase 0. Note that this calcium influx is slower than an another ion would be.
731
What does rifampin do?
Block bacterial (DNA-dependent) RNA polymerase.
732
What makes bruises green?
Heme oxygenase turns bilirubin into biliVERDIN.
733
In the setting of metabolic acidosis, a patient will use H2PO4- as a buffer to trap H+ ions that it wants to excrete so urine levels of H2PO4- will ______ as will urine levels of NH3.
INCREASE!
734
Which step in the citric acid cycle creates GTP?
The conversion of succinyl CoA to SUCCINATE which is accomplished by SUCCINATE thiokinase or SUCCINATE synthetase. Not the same as the dehydrogenase btw).
GTP is used by PEP-carboxykinase to make PEP into oxaloacetate.
735
What does EFFERENT ARTERIOLE constriction do to GFR?
It increases GFR due to increased glomerular hydrostatic pressure. It REDUCES RPF. This means FF increases.
Note: after too much efferent arterial constriction, the Oncotic pressure in the glomerulus starts to increase due to much slower RPF and at SEVERE, efferent arteriolar constriction,
736
Why are reticulocytes blue on Giemsa stain?
Ribosomal RNA that is maintained because of accelerated release of immature erythrocytes.
737
What is the BIGGEST risk factor for a lung abscess EVEN in the setting of smoking?
It remains aspiration! So seizure disorder is possible. Peptostreptococcus and Fusobacterium are ANAEROBES
Smoking increases one's risk of community acquired PNEUMONIA like S. Pneumoniae and mycoplasma due to impaired pulmonary defenses.
738
What is one of the biggest things that must be monitored in following Ankylosing spondylitis?
Chest expansion -- due to enthesopathies (tendon insertion) of the constochondral and costoverterbral joints which may limit chest movement leading to hypoventilation.
739
What causes ISOLATED increase in SBP in elderly patients?
Aortic stiffening (this means the AORTA stiffens) as does its proximal branches.
740
What is Dobutamine's biggest effect?
What effect do it and nitroglycerin share in common?
What is the risk of Dobutamine?
Dobutamine's biggest effect is on CONTRACTILITY/MYOCARDIAL OXYGEN CONSUMPTION. -- it is an ionotrope.
Dobutamine is also a weak chronotrope meaning it will increase heart rate. Nitroglycerin also increases heart rate though it does so indirectly because it's venodilation leads to a reflex tachycardia. The difference however, is that nitroglycerin (unlike Dobutamine) will DECREASE myocardial oxygen consumption which is why it is used in angina.
Dobutamine INCREASES cardiac conduction velocity increasing RISK OF ARRYTHMIAS.
741
Where is glucagon synthesized in the pancreas?
What is the nature of the rash in glucagon and what other symptoms do they have?
Alpha cells.
Rash is necrolytic -- lesions enlarge, coalesce with bronze colored central area of clearing. The pts also experience abdominal pain, diarrhea. Also, normocytic anemia resembling anemia of chronic disease is present.
742
What cardiac pathology is a bifid carotid pulse with brisk upstroke characteristic of?
Hypertrophic cardiomyopathy.
743
What are hydropic villi and trophoblastic proliferation consistent with?
Invasive MOLE! This means there has been invasion of the myometrium. This is consider a locally invasive NON-METASTASIZING tumor.
The risk of this following complete mole pregnancy is 10-20% and can be monitored with beta-hCG much like the monitoring for choriocarcinoma which is entirely different.
Treatment is chemotherapy just like chorio. It is also very responsive.
744
What causes the theca-lutein cysts seen in gestational trophoblastic disease?
The bhCG excessive stimulation!
745
What is the pathology associated with choriocarcinoma?
Atypical cytotrophoblasts and syncthiotrophoblasts with foci of hemorrhage and necrosis!
746
What are acarbose and miglitol?
They are alpha glucosidase inhibitors meaning they inhibit BRUSH BORDER MEMBRANE BOUND ENZYMES known as Dissacharidases to DELAY carbohydrate absorption. They are used in diabetes and best taken with a meal.
Carbohydrates are normally absorbed as monosaccharides.
747
How does exenatide, a GLP-1 agonist, exert its effect in diabetes?
Exenatide works via cAMP and since GLP-1 produced by the intestinal L cells promotes satiety, decreases gastric emptying, and increases insulin release, it does the same thing!
748
What does the equilibrium potential of each ion represent?
The equilibrium potential represents how that ion would affect the membrane potential if it were completely permeable to IT!
That means for example that since the equilibrium potential for Ca2+ is +125mV, were the membrane completely permeable to Ca2+, it would shift the potential of the membrane in that direction. What this means is that if a question of a hypothetical cell is shown to me with different ion and their permeabilities, I need to eliminate answer choices based on first where the resting potential is. If the resting potential is negative, then any of the ions with a NEGATIVE EQUILIBRIUM potential can be responsible and so on.
749
Leprosy. What is the significance of the heat killed mycobacterium leprae test?
The heat killed, LEPROMIN test is akin to the PPD for leprosy. It tells you whether a Th1 predominant response (cell-mediated immunity) is taking place. If it is positive then the answer is yes and BACTERIAL LOAD is LOW. Pts with this response has HIGH IL-2, IFN-gamma, and IL-12 in these lesions. It is the Th1 response that can cause damage to the skin and nerves. The above described reaction is a TUBERCULOID RESPONSE. This can be pretty effective at clearance.
Eventually Th2 takes over LEADING TO LEPROMATOUS RESPONSE.
If it is negative, a Th2 response (humoral immunity) has now taken over and bacterial load is likely to be HIGH.
750
A child who is irritable, feeds poorly, vomits, and has current weight at 45th percentile and head circumference at 96th percentile with WHITE-YELLOW CHORIORETINAL LESIONS AND INTRACRANIAL CALCIFICATIONS is concerning for...
When was the infection acquired?
Congenital toxoplasmosis.
In-utero infection - vertical transmission. Especially if mom gets first time Toxo infection in the first 6 months of pregnancy.
Please note the enlarged head circumference is due to hydrocephalus.
751
What anti-TB drug requires the activity of bacterial CATALASE-PEROXIDASE to be active in inhibiting mycolic acid synthesis? How can it be evaded by Mycobacteria?
Isoniazid. It can be invaded simply by the bacteria downregulating the activity of their CATALASE-PEROXIDASE.
752
An anti-Hyperlipidemia drug that is associated with skin flushing, warmth, (itching) is...
How is this effect mediated?
Niacin; prostaglandins. You can avoid this by simply having the patient take ASPIRIN beforehand. Over time, tachyphylaxis occurs and aspirin is no longer needed.
753
What topical treatment works by decreasing the level of substance P in the PNS?
Capsaicin!
754
What is pathophysiology behind red man syndrome seen in Vancomycin?
Histamine release!
755
How does strep Viridans cause valvular subacute bacterial endocarditis after a dental procedure -- what must it adhere to?
Fibrin-platelet aggregates so the must have been prior injury.
756
What is a famous AChE inhibitor used in the treatment of Alzheimer's?
Donepezil
757
Please note that cholestatic conditions can cause HYPERCHOLESTEROLEMIA. This includes PBC and xanthelasmas can be associated with it.
Repeat.
758
What 2 drugs can be used in the setting of tumor lysis syndrome?
Allopurinol and Rasburicase. Rasburicase inhibits URATE OXIDASE. The important thing to remember is that tumor lysis is marked by hyperphosphatemia, HYPOCALCEMIA, hyperkalemia, hyperuricemia.
759
The intimal response of intimal thickening and collagen deposition in remaining arteries after an MI is directed by...
Smooth muscle cells. NOT macrophages. Smooth muscle cells.
760
Where is telomerase expressed?
In stem cells and in cancer cells. It has reverse transcriptase ability meaning it is a RNA-dependent DNA polymerase. It adds TTAGGG to the 3' end.
761
Pts on opioids NEVER seem to develop tolerance to the following two side effects:
Constipation and miosis.
762
How do levodopa, carbidopa, and entacapone work?
Levodopa is the precursor to dopamine. Peripherally, it is metabolized dopa decarboxylase (DDC) so it is often given WITH carbidopa. Carbidopa inhibits this peripheral enzyme. Even so, only 10-20% of levodopa is getting to the brain.
One of the reasons why is that COMT - catechol O methyl transferase is ANOTHER enzyme that can break down levodopa that is not blocked by carbidopa. COMT METHYLATION of Levodopa is blocked by entacapone and tolcapone. Thus ENTACAPONE only decreases PERIPHERAL DOPAMINE degradation and thereby increases available levodopa.
763
In normal osteoporosis that is NOT caused by any medical condition, what are the levels of PTH, Calcium and phosphorus.
Calcium, PTH, and phosphorus are all NORMAL!
764
What else that is associated with visual problems and/or headache can poliovirus cause as it is an enterovirus?
Aseptic meningitis.
765
In a pt with bipolar disorder who develops extra pyramidal symptoms and/or delirium, pay attention to medications that can decrease Lithium excretion by the kidney at the PCT. This includes Thiazide diuretics, NSAIDs, and ACE inhibitors. Loop diurectics DO not do this. It does not occur with loop diuretics because although they also deplete sodium, the kidney can still absorb more sodium at the DCT so it does not increase proximal sodium absorption as much.
What is the only way to get rid of very high levels of lithium?
Repeat.
Dialysis.
766
What is mifePRISTONE?
| -TONE.
A progesterone ANTAGONIST!!! This is RU-486. Causes expulsion of fetus by decidual necrosis etc. it also Potentiates the uterus to the effects of those famous pain causing substances.
767
What is misoPROSTOLOL?
It is a PGE1 analogue and can even prevent from NSAID-induced GI ulcers.
768
When diabetes affects the oculomotor nerve and causes ischemia, what is spared?
The parasympathetic fibers which are on the outside of the nerve are spared!!!
769
A 46 year old male is being worked up for abdominal pain, weight loss, and diarrhea and has an intense PAS stain in the intestine.
Whipple disease. Note PAS stain is for GLYCOPROTEIN. Whipped is gram positive actinomycete that stains Magenta with PAS stain and is diastase resistant.
770
Why does Candida vulvovaginitis occur?
DECREASED GRAM POSITIVE BACTERIA IN THE VAGINA due to antibiotic use. Other causes: systemic Corticosteroid therapy, contraceptive use, diabetes mellitus, immunosuppression.
771
What is a very serious side effect of methimazole and PTU? (The thionamides - anti-thyroid drugs)
Agranulocytosis.
772
What immune signal is responsible for Cachexia?
How does it do this?
TNF-alpha.
It is thought to down regulate LPL, suppress appetite, and induce insulin resistance.
773
Only a PPI can inhibit gastric acid secretion in response to all the stimuli like vagal, histamine, and gastrin.
Repeat.
774
Even when Haemophilus Influenza Type B causes an infection in the joint, what virulence factor is responsible?
Capsule! Capsule! This polyribitol phosphate capsule evades complement destruction by C3b unless opsonizing antibodies and a functioning spleen are present.
775
Why is a pancreatic pseudocyst referred to as a pseudocyst and not a REAL cyst?
What is it lined by?
Because it is not lined by epithelium.
It is lined by fibrous and granulation tissue.
776
What is the double wave normally seen in the jugular venous pulse diagram.
A wave - atrial contraction
C wave - bulging of tricuspid valve in response to R ventricular contraction.
X descent - atrial relaxation prior to the upcoming v wave.
In atrial fibrillation, the atria don't contract so expect the a wave to be absent.
777
Progressive Dyspnea, chronic edema, and ascites in an immigrant can be
Especially if there is a rapid, steep y descent during inspiration on jugular venous pulse.
Constrictive pericarditis.
778
What part of the nephron is dilated in autosomal dominant Polycystic kidney disease?
Cyst proliferation at ANY point in the nephron. Tubular cell proliferation and fluid secretion are caused by abnormality in PKD 1 or PKD 2. Less than 5% of nephrons affected. Liver cysts also can be present.
779
What part of the nephron is dilated in autosomal RECESSIVE Polycystic kidney disease?
Dilated distal tubule and collecting duct.
780
What is the triad of hemolytic uremic syndrome which happens due to Shiga toxin?
Microangiopathic hemolytic anemia, THROMBOCYTOPENIA and regal failure.
781
What is the pentad of thrombotic thrombocytopenia purpura?
Fever, renal failure, thrombocytopenia, MAHA, neurologic dysfunction.
782
What does phosphorylation do to Rb protein is it pro-DNA synthesis signal or anti?
Hyperphosphorylated Rb is INACTIVE! The best way to recall this that cyclin dependent kinase 4 is what phosphorylates Rb resulting in progression from G1 to S phase.
783
What is the most common cardiac abnormality that predisposes an individual to native valve bacterial endocarditis?
Mitral valve prolapse!
784
What kind of nephropathy might one expect to see in the setting of acyclovir?
Crystalline.
785
Peau d'orange describes lymphatic obstruction, PITTING edema in breast cancer that occurs when dermal lymphatic vessels are plugged.
Repeat.
786
If a patient feels SHARP pain the first week after an MI that is exacerbated by swallowing, what is going on?
The patient has PERICARDIAL INFLAMMATION THAT IS DIRECTLY OVERLYING THE NECROTIC TISSUE FROM THE MI. This is not an immunogenic inflammation
It takes at least one week after to months after before immunogenic causes begin.
A recurrent MI would repeat itself as crushing, substernal chest pain
787
What is the pathogenesis of Arnold-Chiari malformations?
Congenital! These malformations are due to impaired development of the posterior fossa. The Type 1 malformation is relatively benign and does not show up until adulthood.
788
What are the 2 most important things to ascertain in the setting of metabolic alkalosis.
Volume status and urine chloride. If pt is volume deplete and urine chloride is low, vomiting or NG auctioning is likely responsible. This is a saline responsive metabolic alkalosis because in the absence of Cl-, it is difficult for kidneys to excrete excess HCO3-
Similarly if a pt is on Thiazide or loop diurectics, they will also be volume deplete and urine chloride will be high. If they recently stopped, urine chloride will be low. This is also saline responsive metabolic alkalosis.
Lastly, individuals with mineralocorticoid excess activity like in Conn's syndrome (primary hyperaldosteronism) or in Cushing syndrome will have a saline Non-responsive metabolic alkalosis. Bartter's and Gitelman syndrome also fit in this category.
High urine chloride is anything above 20mEq.
789
What form of Stronglyoides is excreted?
Rhabtidiform - non infectious. Filarial form is infectious. Treat with ivermectin.
790
What is the biggest measure of insulin resistance?
Waist-to-hip ratio which is a proxy for VISCERAL fat.
| SubQ fat is less important. It is the VISCERAL fat to SubQ fat ratio that matters.
791
What is the pathophysiology of AKI?
In the INITIATION phase, you have the injury -- hemorrhage, sepsis etc that leads to renal tubular damage.
In the MAINTENANCE PHASE you become oliguric meaning hyperkalemia, fluid overload, and increased BUN/Cr become an issue.
In the RECOVERY PHASE you develop a hypotonic, high volume diuresis where you loss many ions. Risk is Hypokalemia, hypomagnesemia, hypocalcemia, hypophosphatemia
792
What lung cancer should not be removed surgically?
Small cell lung cancer. Just chemotherapy and radiation as this individual is most likely to have metastases. Even if there are no mets, chemo and radiation is the way to go.
793
What therapy is the go-to for all the tapeworms and flukes?
Praziquantel
794
Angioma -- Von-Hippel Lindau. Especially hemangioblastoma in the retina and/or cerebellum, as well as congenital cysts and neoplasms in kidney, liver, pancreas. Increased risk of renal cell cancer.
hamartomas -- _____
Tuberous sclerosis.
795
What two abnormalities are common adverse effects of Amphotericin B and where in the nephron does it usually affect membrane permeability?
Distal convoluted tubule. Hypokalemia and HYPOMAGNESIA.
796
What are the 2 inhibitors of porphyrin synthesis?
Glucose and heme.
797
What amino acid is the precursor of nitric oxide?
Arginine! Nitric oxide is synthesized from arginine by nitric oxide synthase. This then goes on to promote vasodilation by stimulating the production of cGMP.
798
In the process of wound healing, EXCESSIVE Actin containing fibroblasts and matrix metalloproteinases activity suggest
Contracture formation.
799
What is the main enzyme that INACTIVATES 6-MP (which works to block de novo purine synthesis)?
6-MP and 6-thioguanine are pro drugs that need to be metbolized to be active. What enzyme metabolizes them?
6-MP and it's related drugs are INACTIVATED by Xanthine oxidase.
Since 6-MP is a prodrug, it actually requires processing by HGPRT to become active.
800
What poison smells like sweet almonds?
Cyanide
801
How in the setting of atrial fibrillation does Digoxin work to reduce HR?
Note this is different from its effects on ventricular contractility.
Digoxin increases parasympathetic output/canal tone directly.
802
What poison smells like garlic?
Arsenic.
803
The only cancer with a Ki-67 approaching 100% is ...
Burkitt Lymphoma regardless of where the tumor is.
804
How does radiation cause injury in cancer cells?
Radiation introduces double strand DNA breaks and causes formation of reactive oxygen species that also damage DNA.
This radiation is not the same as UV radiation.
805
What substance does VWF normally bind to?
Von Willebrand's factor binds to COLLAGEN.
It also promoters platelet adhesion by binding to GPIb on platelet and then connecting the plug with collagen.
806
What substance do Auer rods have in them?
MyeloPEROXIDASE
807
What is tartrate resistant acid phosphatase associated with?
Hairy Cell Leukemia. B cell origin. CD 20+.
808
Where can TdT be found?
Immature B and T cells. It is the enzyme that adds nucleotides to the VDJ regions of the antibody gene for antibody diversity.
809
Acidophilic bodies in the liver, I.e. Acidophilic hepatocytes suggest ...
Apoptosis. Seen in any of the viral hepatitis. Also pan lobular lymphocytic infiltrate and hepatocytes necrosis.
810
Lactose is also known as
Galactosyl beta 1,4 glucose
811
What diseases can cause pulsus paradoxus which will appear as a person for whom initially, the blood pressure sounds are only heard on exhalation and then as the cuff is lowered they are also heard on inspiration. Recall pulsus paradoxus is a more than 10mmHg drop in SBP.
Cardiac tamponade, constrictive pericarditis, severe obstructive pulmonary disease, and restrictive cardiomyopathy.
812
How do beta-2 agonist bronchodilators work?
Increase cAMP.
813
Which pathogen blocks the 60s subunit directly?
EHEC Shiga like toxin (E.Coli O157:H7) and Shigella.
814
Which pathogen ribosylates the protein synthesis machinery?
Diphteria.
815
Chronic rheumatic fever is often associated with which mitral valve pathology?
This is contrast or infective endocarditis which eats the valve causing...
Chronic rheumatic fever leaves a FIBROTIC valve cause MITRAL STENOSIS.
Infective endocarditis eats at the valve causing mitral REGURGITATION.
816
What is the biggest prognostic predictor of disease course in post streptococcal glomerulonephritis.
AGE. Adults do worse. 95% of kids recover vs 60 percent of adults. It can become RPGN or chronic glomerulonephritis.
817
What causes abdominal aortic aneurysms?
Intimal (fatty) streak. Lipid laden foam cells derived from macrophages and smooth muscle cells have engulfed LDL.
An abdominal aortic aneurysm is atherosclerotic NOT dissection.
818
What is the best treatment for restless legs?
Pramipexole (dopamine agonist)
819
What do the levels of the HPA Axis look like in anorexia?
Completely shut down. LH, FSH, and estradiol are all DECREASED!
820
How does isopropyl alcohol exert its effect on a wound?
It disrupts the cell membrane AND denatures proteins.
821
In a pt with fructokinase deficiency, what hormone is actually responsible for fructose metabolism?
Hexokinase!!!
822
What does UDP-4-epimerase do?
It is what turns Glucose-1-phosphate that was made by uridyl transferase in the galactose pathway to Glucose 6-phosphate.
823
Adrenogenital disease or congenital adrenal hyperplasia in a male with 21 hydroxylase deficiency can be DELAYED in presentation and show up at school age. Histology will show adrenal hyperplasia. Appropriate therapy is directed at inhibiting ACTH with exogenous steroids because 21 hydroxylase deficiency leads to low levels of cortisol which leads to increased ACTH from pituitary.
This little boys do NOT have salt wasting because the minimal amounts of 21 hydroxylase activity they have is suffix eg.
Repeat.
824
Ganciclovir and zidovudine together can predispose to:
Neutropenia!
825
For a patient with Pyruvate dehydrogenase deficiency, only Purely ketogenic amino acids should be given. What 2 are these?
Leucine and Lysine. They do not increase blood lactate levels in the patient.
826
Niacin is associated with INCREASED insulin resistance so increase diabetic drugs for patients on it may be necessary.
Repeat.
