Notes Flashcards
What do you give a cancer patient on Methotrexate to ensure that he or she doesn’t suffer from pancytopenia and apthous ulcers?
Give Folinic Acid (or leucovorin), which is a 5-formyl-derivative of THF, which doesn’t require dihydrofolate reductase (DHF reductase) to be converted to THF. THF is a methyl donor used in amino acid synthesis, thymidilic acid synthesis, and purine synthesis. MTX acts on DHF reductase to inhibit downstream DNA synthesis of all cells, including cancer cells. Side effect is to suppress bone marrow and GI tract mucosa.
What are the normal values for aPTT and PT? What do each of these test?
PT: 11-14 seconds (Extrinsic: FVII)
aPTT: 25-35 seconds (Intrinsic: FXII, FXI, FIX, FVIII)
What is odansetron?
5-HT3 inhibitor of GI tract/area postrema/solitary nucleus & tract, used for nausea prevention (especially after chemotherapy)
What traverses through the Cribiform plate?
CN I Olfactory bundles
What traverses through the Optic Canal, in the middle cranial fossa?
CN II, opthalmic artery, central retinal vein
What traverses through the Superior orbital fissure?
CN III, IV, V1, VI, opthalmic vein, and sympathetic fibers
What traverses through the foramen rotundum?
CN V2 (Maxillary)
What traverses through the foramen ovale?
CN V3 (Mandibular)
What traverses through the foramen spinosum?
MMA (middle meningeal artery) and vein
What traverses through the internal acoustic meatus?
CN VII & VIII
What traverses through the Jugular foramen?
CN IX, X, XI, jugular vein
What traverses through the hypoglossal canal?
CN XII
What traverses through the foramen magnum?
Spinal roots of CNXI (spinal accessory), brain stem, and vertebral arteries
What is Vernet Syndrome?
Lesions of the jugular foramen cause CN IX, X, XI dysfunction:
- CN IX - loss of taste from posterior 1/3 of tongue, reduced parotid gland secretion
- CN IX/X - loss of gag reflex, dysphagia
- CN X - dysphonia and hoarseness, soft palate drop with deviation toward normal side
- CN XI - SCM and trapezius muscle pareses
Where does negative selection in T-cell maturation occur?
Medulla of the Thymus, with thymic medullary epithelia and dendrites. Serves to eliminate T cells that are overly autoreactive. (Positive selection occurs prior to negative selection in the thymic cortex.)
In carbon monoxide poisoning, how will PaO2 and % carboxyhemoglobin be affected?
CO poisoning does not affect the partial pressure of oxygen in the plasma; it only affects the amount that is able to bind to hemoglobin. CO has a much higher affinity than O2. Carboxyhemoglobin will increase to >2%. Note: CO poisoning has nothing to do with methemoglobinemia.
How do you calculate Attributable Risk Percent? (The % of an outcome that can be attributed to a risk factor)
ARP is the excess risk in the exposed population that can be attributed to the risk factor. Can use the RR to get the ARP:
ARP = (RR-1)/RR or (risk in exposed - unexposed)/risk in exposed
What is the mainstay of DVT treatment in a pregnant woman?
Heparin, to increase ATIII activity which inhibits FIIa and FXa
(Coumadin, the normal drug of choice for DVT, is teratogenic!)
What chromosome carries the Bcl gene?
Chromosome 18, protooncogene for B cell lymphomas
What chromosome carries the C-myc gene?
Chromosome 8, oncogene, Burkitt lymphoma
What chromosome carries the immunoglobulin heavy chain enhancer element?
Chromosome 14
translocations can cause cancer:
- t(14;18) is Follicular Lymphoma with Bcl
- t(8;14) is Burkitt’s with c-myc
- t(11;14) is Mantle cell lymphoma with cyclin D (G1-S transition)
What drug has potent anti-inflammatory effects but without the side effects of bleeding and GI ulceration?
Selective COX-2 Inhibitors (i.e. celecoxib) do not impair platelet function because platelets predominantly express COX-1.
How does the Parvovirus attach to RBCs?
P antigen
How does HIV attach to T cells?
gp120 on viral envelope to CD4 on T cells, in addition to the coreceptor CXCR4 and CCR5.
How does CMV attach to cells?
GAGs on host cell surface
How does EBV bind?
EBV gp350 with CD21 on B cells
What is Warfarin’s mechanism of action?
It inhibits vit. K dependent gamma-carboxylation of glutamic acid residues of clotting factors 2, 7, 9, 10.
What is used to treat Heparin-induced Thrombocytopenia?
HIT paradoxically causes thrombosis. Use argatroban, which is a direct thrombin inhibitor.
What is the major regulator of iron metabolism in the body?
Hepcidin, made by liver as an acute phase reactant, causes the internalization of ferroportin in enterocytes and macrophages. (Stops transport in the GI tract and stops Fe release by macrophages).
How do CYP enzymes affect Warfarin therapy?
CYP 450 2C9 inhibitors INCREASE activity.
CYP 450 2C9 enhancers DECREASE activity.
Rifampicin, phenobarbital, and phenytoin are universal CYP450 enhancers and will decrease the activity of Warfarin to below therapeutic levels. (Inhibitors include cimetidine, amiodarone, bactrim, and flagyl)
What kind of mutation is involved in HbC and HbS disease?
Missense mutation (single base substitution cause coding for a different amino acid)
HbS (glutamate -> valine) - neg to nonpolar
HbC (glutamate -> lysine) - neg to positive
The speed of Hb during gel electrophoresis: HbA>HbS>HbC
What organism is diagnosed by performing a germ tube test?
Candida albicans.
Vinca Alkaloids are used to treat what?
Cancer treatment that halts the cell cycle in Mitosis, by inhibiting spindle-microtubule formation and separation of daughter cells.
Can be neurotoxic -> peripheral neuropathy.
What is necessary for diagnosis of Acute Intermittent Porphyria?
Elevated ALA and porphobilinogen during acute attacks.
Usually comes with abdominal pain and neurological distress, and often due to increased activity of ALAS after decrease in heme synthesis (due to alcohol, barbiturates, and hypoxia).
Auer rods stain positively for what enzyme? What do these findings indicate?
peroxidase, AML
What is adding during the sickling test?
sodium metabisulfite
What cancers are related to mediastinal mass?
Thymoma, Hodgkin’s lymphoma, T-ALL, DLBCL with primary mediastinal involvement.
What the stop codons?
UAA, UAG, UGA
Mutation to a stop codon = “nonsense mutation”
What are the 8 types of AML?
M0 - Minimally differentiated AML M1 - AML without differentiation M2 - AML with maturation M3 - APL -- associated with t(15;17) M4 - Acute myelomonocytic leukemia M5 - Acyte monocytic leukemia M6 - Acute erythroleukemia M7 - Acute megakaryocytic leukemia
How do you calculate the number needed to harm?
NNH = 1 / Attributable Risk
where Attributable Risk = Event rate of intervention - Event rate of placebo
This calculation is similar to number needed to treat (NNT)
What disease is associated with diffuse sheets of large lymphocytes with nuclei >5x the size of small lymphocytes found on lymph node biopsy?
Large B-Cell Lymphoma
After transfusion, will stored red blood cells lose or gain electrolytes?
They can gradually lose intracellular potassium to the surrounding solution, potentially causing hyperkalemia.
What antiviral role does Raltegravir play in HIV therapy?
Raltegravir is an integrase inhibitor that ultimately halts mRNA transcription.
After viral entry and the reverse transcriptase-dependent formation of a double-stranded DNA intermediate, integrase inserts the viral dsDNA into host cell chromosomes to become a provirus. Inhibition of integrase prevents the virus from using human RNA pol II to transcribe its message.
Name 2 protease inhibitors used in HIV therapy.
Saquinavir, Ritonavir
Name a fusion inhibitor of HIV.
Enfuvirtide, which binds to HIV’s gp41 on the envelope and thereby prevents it from undergoing a conformational change necessary for fusion.
Name a reverse transcriptase inhibitor used in HIV therapy.
NNRTIs: nevirapine, efavirenz, delavirdine
NRTIs: zidovudine, zalcitabine, tenofovir, lamivudine
What is maraviroc’s mechanism of action?
HIV antiviral – CCR5 antagonist that blocks HIV attachment and entry of other CCR5-tropic viruses into the the CD4+ T cell.
Should you increase or decrease doses of 6-mercaptopurine and 6-thioguanine when taken with allopurinol?
You should decrease the dose!
6-MP and 6-TG are activated by HGPRT, but inactivated by xanthine oxidase. If XO is inhibited by agents like allopurinol, metabolism of 6-MP and 6-TG is inhibited, and toxic levels can be achieved.
What do azathioprine, 6-MP and 6-thioguanine do?
Anti-neoplastic purine analogs that inhibit purine synthesis.
Used in organ rejection prevention, RA, SLE (aza)
leukemia, IBD (6MP and 6TG)
What enzyme can be deficient in severe combined immune deficiency (SCID) and is also over-expressed in some malignancies?
Adenosine deaminase, which converts adenosine to inosine in purine metabolism.
Pentostatin is a cytotoxic purine analog/irreversible inhibitor of ADA.
Cladribine is a cytotoxic purine analog/resistant to ADA degradation.
What is the major adverse effect of Zidovudine?
Bone marrow suppression
It is a DNA polymerase inhibitor.
What is a major adverse effect of Foscarnet?
Associated with numerous electrolyte abnormalities.
What two drugs are commonly associated with the formation of SJS or TEN?
Nevirapine and efavirenz, two antivirals.
Carbon tetrachloride causes cell injury through what mechanism?
CCl4 is oxidized by the P450 system, which forms free radical CCl3. This radical interacts with lipids in membranes, degrading them and forming H2O2, in a process called lipid peroxidation.
What DNA mechanism is messed up in Lynch/NPCC1 syndrome?
DNA Mismatch Repair
What disease puts AIDS patients at higher risk of Non-Hodgkins Lymphoma?
EBV-induced B-lymphocyte proliferation
H. pylori infection is implicated the in the pathogenesis of what kind of cancers?
Gastric adenocarcinoma and MALToma.
BK Virus primarily causes what two diseases in the immunocompromised?
Nephropathy or hemorrhagic cystitis.
How does nitrite exposure affect oxygenation?
Nitrites cause poisoning by oxidizing heme iron to the ferric state. (Normally, iron is in the ferrous (II) state. Methemoglobin is formed from Iron, and it is unable to bind oxygen. Thus, a state of functional anemia is induced.
Fe2+ –> Fe3+ (methemoglobin)
PaO2 will be normal because amount of oxygen dissolved in the plasma is the same and is unrelated to Hg function. All measures of bound oxygen and carrying capacity will decrease.
What causes a right shift in the oxygen dissociation curve?
Increased H
Increased 2,3 DPG
Increased Temp
Rightward shift = less affinity for O2, unloading is easier.
What causes a leftward shift?
Decreased H
Decreased 2,3 DPG
Decreased Temp
Leftward shift = increased affinity to O2
What kind of antiretrovirals do not require activation via intracellular phosphorylation?
NNRTIs, like nevirapine, efavirenz, delavirdine.
How do T-cells look on a blood smear in a patient with infectious mononucleosis?
CD8+ T cells will clonally expand in response to the EBV virus, to kill infected B cells. They will classically appear as much larger cells with abundant cytoplasm, an eccentrically-placed nucleus, and a cell membrane that appears to conform to the borders of other neighboring cells.
What do matrix metalloproteinases degrade?
Zinc-containing enzymes that degrade ECM and BM, composed primarily of laminin and collagens 4 and 6. Normal part of tissue remodeling and embryogenesis. Role in invasive metastases of cancer through BM.
What is hemoglobin Gower and when is it found in the blood?
Earliest hemoglobin in fetus, synthesized by the yolk sac and is replaced by Hb Portland, then Hb Gower 2, before HbF production begins at 10-12 weeks.
When do infants start switching to HbA from HbF?
First 6 months of life
What DVT treatment would prolong aPTT and PT, but not TT (thrombin time)?
Direct factor Xa inhibitors have the most specific activity against factor Xa, without inhibiting thrombin.
What kind of leukemia is associated with Down’s Syndrome?
ALL and AML
ALL > 5 yrs in children with Down’s
AML < 5 yrs in children with Down’s
In a normal distribution, 95% of observations will lie between what two parameters?
+/- 2 standard deviations of the mean.
Only 68% lie within 1 SD of the mean.
99.7% lie within 3 SD of the mean.
What are Gardos channel blockers used for?
In Sicklers, Gardos channel blockers hinder efflux of K+ and water from the cell (via a Ca2+ dependent channel), preventing dehydration of the erythrocytes. Dehydration and deoxygenation of Hb causes HbS to polymerize. Thus, Gardos channel blockers reduce HbS polymerization.
What are risk factors for ovarian cancer?
Infertility, nulliparity, miscarriages, ovarian dysfunction, and use of clomiphene citrate to induce ovulation – probably due to irregularities of reparative processes of ovarian surfaces.
What can decrease the risk of ovarian cancer in women?
- Use of OCPs because limits the number of ovulations a woman will have –> less ovulations –> less surface repair
- Multiparity
- Breastfeeding
Why do sicklers experience acute chest syndrome, abdominal pain and bone pain?
Due to vaso-occlusive events in the lungs, spleen, and bone.
What is one of the most common ways to get hemolytic uremic syndrome?
Eating undercooked, contaminated ground beef that has EHEC O157:H7.
What is the drug of choice for malaria?
Usually, in areas known to have chloroquine sensitivity, chloroquine is the treatment of choice. In Africa, there is some resistance, so you can treat with mefloquine, a quinine analog. Primaquine is required to kill vivax and ovale schizonts.
What is abciximab and when is it used?
Abciximab is a chimeric mouse-human monoclonal Ab against GpIIb/IIIa receptor on platelets. It is used to block the final step in platelet aggregation, and during angioplasty procedures in patients with acute coronary syndrome.
How is IL-2 used as a chemotherapy?
IL-2 acts to regulate the activation and differentiation of T cells to aid in tumor destruction.
What is Infliximab?
A monoclonal IgG1 Ab against TNF alpha, used in RA, ankylosing spondylitis, and Crohn’s disease.
What is Bruton’s agammaglobulinemia?
X-linked immunodeficiency that results in a deficiency of all forms of Ab and low B cell counts due to a defect in B cell maturation. May lack germinal centers and primary lymphoid follicles in lymph nodes.
Predisposed to recurrent pneumonias
What is the folate trap?
Vitamin B12 (cobalamin) is required for the conversion of homocystine + N-5-methyl-THF –> methionine + THF. A methyl group on methylated THF is transferred to homocystine.
Vitamin B6 is required for the synthesis of what?
Vitamin B6 is required for both steps in the conversion of homocystine to cystathionine to cysteine (with cytathionine synthase and cystathionase as enzymes, respectively.)
B12 is used in the process of converting _______ to succinyl coa.
Methylmalonyl CoA
Increased in B12 deficiency, but NOT in folate deficiency.
Inhibition or deficiency of Protein C can predispose patients to _______
Warfarin-induced skin necrosis. Warfarin decreases carboxylation and function of anticoagulant proteins C and S. Once started, it can reduce protein C activity by nearly 50%, resulting in a transient hypercoagulable state.
What are some natural anticoagulants found in the blood?
ATIII, Protein C, Protein S
What kind of receptor is JAK2 (mutated in some myeloproliferative diseases)?
Non-receptor tyrosine kinase.
In polycythemia vera, can be associated with epo-receptor.
What is mutated in Li-Fraumeni syndrome?
p53 tumor suppressor.
AD, predisposition to variety of cancers
Some cells have alternate glycolytic pathway that produces no net ATP. What kind of cells do this?
Erythrocytes.
What respiratory structure is covered by stratified squamous epithelium? What type of microbe has an affinity for this structure?
True vocal chords. Stratified squamous epithelia is mostly found in the oropharynx, laryngopharynx, anterior epiglottis, upper part of the posterior epiglottis and the true vocal chords.
Most of the other upper respiratory structures are lined by ciliated, pseudostratified, columnar, mucus-secreting epithelia.
A small DNA virus that has an affinity for this epithelia is a small DNA virus like HPV.
Why do you check the phospholipid content of amniotic fluid?
To assess fetal lung maturity, because PL is a major component of pulmonary surfactant (ie Lecithin:sphingomyelin ratio >2 is mature).
When you suspect fetal neural tube defects, what should you test?
Elevated AFP in amniotic fluid, which suggests closure defects like spina bifida.
What do you test if you want to detect a fetal adrenal disorder?
Amniocentesis, to measure 17-hydroxyprogesterone levels;
Gene linkage analysis involving HLA region or chromosome 6; or detection of abnormal genes via molecular probes.
What accumulates within cell lysosomes in Tay-Sachs disease?
GM2-ganglioside accumulates in TS disease because of a deficiency in beta-hexoaminidase A.
What kind of inheritance pattern is observed in Tay-Sachs?
Autosomal recessive neurodegenerative disease.
What are telltale signs of Tay Sachs?
At 2-6 months, babies develop progressive weakness, hypotonia, loss of motor skills, abnormal startle reflex with acoustic stimuli, cherry red macula.
How do you distinguish Niemann-Pick from Tay Sachs?
TS has no hepatosplenomegaly.
What activates trypsinogen to trypsin?
duodenal enterokinase
Where is the duodenal bulb?
Begins at the pylorus, is posterior to the gallbladder and liver, ends at the neck of the gallbladder. Ulcers here can cause hemorrhage (as opposed to anterior bulb ulcers which can cause perforation).
What is the only IV agent that improves renal perfusion while also lowering BP?
Fenoldopam, a Dopamine-1 selective receptor agonist. Used for short-term management of severe hypertension and can be safely used in hypertensive crises. Causes arteriolar dilation, natriuresis.
What are some digoxin toxicities? Why do you see these more as the patient ages?
Visual changes and GI disturbances. Because of decline of renal clearance relative to age. Digoxin is renally cleared.
In congenital adrenal hyperplasia, what is the most common type?
21-hydroxylase deficiency = decreased glucocorticoids and mineralocorticoids, increased androgens.
What does a 17alpha-hydroxylase deficiency impair?
Less common form of CAH, which impairs androgen, estrogen and cortisol synthesis by the adrenal gland, but has normal-high mineralocorticoid production. Will see low androgen, low estrogen, boys with hypogonadism, hypertension and hypokalemia.
A treatment for angle-closure glaucoma also can affect which part of the nephron in the kidney?
Acetazolamide is a carbonic anhydrase inhibitor. Bicarbonate is released into aqueous humor, so a CAI will cause a decrease in intraocular pressure -> decreased secretion.
CA exists in the proximal tubule of the kidney and CAIs can block reabsorption of HCO3- in the PCT, causing an increased urine pH.
Large levels of serum antibody against polyribitol ribose phosphate (PRP) gives protection against what?
H influenza type B epiglottitis.
What are the main features of myasthenia gravis?
Waxing/waning progressive weakness of voluntary muscles (especially those innervated by brainstem motor nuclei), weakness during continued activity, rapid restoration with rest, improvement with cholinesterase inhibitors.
What is Myasthenia Gravis?
Auto-immune disorder with antibodies against the postsynaptic Ach-receptor, causing internalization and complement fixation. Ultimately decreases end plate potential.
What is a cholinesterase inhibitor that can be used for Myasthenia Gravis treatment?
Pyridostigmine can be used, but may cause GI side effects like cramping, nausea, and diarrhea. Can use Scopolamine, a selective muscarinic cholinergic receptor antagonist, to treat side effects.
What is fluoxetine?
Serotonin-substrate reuptake inhibitor (SSRI) used for depression.
What information do you need to do a PCR?
The DNA sequence in the regions FLANKING the target DNA to be amplified.
What kind of DNA pol do you need to use in PCR and why?
Taq polymerase because it is heat stable and will survive the denaturation phase of PCR.
What are the 3 major features of ataxia-telangiectasia disorder?
- Ataxia, due to cerebellar atrophy
- Severe immunodeficiency with repeated sinopulmonary infections
- Increased risk of cancer due to inefficient DNA repair and hypersensitivity to ionizing radiation
Loss of caudate nucleus is seen in what disease?
Huntington
Loss of neurons in the substantia nigrans and presence of Lewy bodies occurs in what disease ?
Parkinsons
What is Ataxia-Telangiectasia?
AR disease with defect in DNA repair genes.
How is schizoaffective disorder different from bipolar with manic episodes and psychotic features?
Schizoaffective disorder is characterized by mood symptoms with concurrent symptoms of schizophrenia. If a patient with schizophrenic history comes in with NEW mood symptoms, think schizoaffective.
How do you calculate an Odds Ratio?
Based on a 2x2 table, ad/bc
As opposed to a RR = [a/(a+b)] / [c/(c+d)]
What nerves does the lower trunk of the brachial plexus carry?
T1 and C8 spinal levels, which ultimately contribute to the median and ulnar nerves (innervate the intrinsic muscles of the hand).
What does injury to the Long Thoracic Nerve cause?
Winging of the scapula due to serratius anterior muscle paralysis
What are the clinical features of Legionella pneumonia?
- High fever with bradycardia
- HA, confusion
- Watery diarrhea
- Hyponatremia
- Gram Stain with many PMNs, but no organisms
Think Legionella when…
Systemic infection (ie with lung, neuro, GI), when patients come from cruise trip or hotel stay.
Unilobar infiltrate on lung CXR to lobar consolidation.
What organism causes cold agglutinins and pneumonia?
Mycoplasma pneumoniae –> tracheobronchitis usually in young adutls though.
What is Losartan?
Angiotensin Receptor Blocker (ARB), that competively binds to AT-1 receptors.
- Stops action of AT II
- Stops negative feedback on renin system, causing increases in renin, AT I, and AT II
- NO EFFECT ON BRADYKININ or ACE ACTIVITY!
What do rodenticides affect?
Most contain brodifacoum, which depletes vitamin K-dependent clotting factors. This causes an acquired coagulopathy. Treat immediately with fresh frozen plasma and vitamin K.
What does cryoprecipate contain?
F8, F13, vWF, fibrinogen
Almost all aminotransferases use ________ as the amino group acceptor.
alpha-ketoglutarate
For example, alanine’s amino group is added to AKG to make pyruvate (for glucose production) and glutamate (which is further metabolized by glutamate dehydrogenase to ammonia, which goes into the urea cycle, and AKG)
_____________ is a major AA responsible for nitrogen transfer to the liver for disposal.
Alanine
How can prolactinomas lead to osteoporosis?
High levels of prolactin suppress GnRH from HTH, which leads to low estrogen in females –> accelerated bone loss.
Multiple Endocrine Neoplasia Type I (MEN I) consists of the triad:
Three P’s
- hyperParathyroid
- Peptic ulcer due to gastrin-secreting tumor of Pancreas
- Pituitary adenoma
What kind of E. coli does not classically ferment sorbitol?
O157:H7 Shiga-like toxin strains do not ferment sorbitol, unlike more other strains. (Also does not produce glucuronidase.)
What bacteria produce toxins that can inactivate EF-2?
Corynebacterium diptheriae and Pseudomonas
What bacteria can release toxins that activate guanylate cyclase and lead to watery diarrhea and electrolyte loss?
ETEC, Yersinia.
What is the presentation of minimal change (MCD) nephrotic syndrome?
- increased permeability of glomerular cap wall -> proteinuria
- proteinuria -> low albumin -> drop in colloid osmotic pressure -> edema
- low intravascular volume -> RAA and ADH triggered –> aldosterone -> sodium & water retention
- liver increases synthesis of proteins (ie lipoproteins -> lipiduria)
In the case of a thromboembolic event in the brain, what microscopic changes will you see 12-48 hours after time of injury?
Red neurons
At 24-72 h, you’ll see necrosis and PMNs. At 3-5 d, macrophages. At 1-2 w, reactive gliosis and vascular proliferation with liquefactive necrosis seen macroscopically. At >2 w, glial scar.
What are the muscles attached to the rotator cuff?
SITS muscles: Supraspinatus, Infraspinatus, Teres Minor, and Subscapularis.
What muscle is responsible for the first 10-15 degrees of arm abduction? For the >30 degrees of arm abduction?
Supraspinatus
What are the hallmarks of catatonic schizophrenia?
Significant disturbance of motor function – abnormal voluntary movements, excessive motor activity, echolalia (imitating other people’s speech), echopraxia (imitating their movements), extreme negativism.
Name the type of bone for each wall of the orbit.
Superior: thick plate of frontal bone
Lateral: thick bone of zygoma and greater/lesser sphenoid wings
Inferior: very thin separating orbit from maxillary sinus
Medial: thin ethmoid and lacrimal bones, separating from ethmoid air cells.
What does the power of a study indicate?
Probability of seeing a difference when one truly exists. Power is reciprocally related to type II error (beta), which states there is no difference between groups where one truly exists!
Power = 1 - beta
What is Type I error?
Describes the probability of seeing a difference when there is NO difference in reality.
What is Type II error?
Probability of stating there is no difference between groups where one truly exists!
What kind of epithelia exists on the ovaries and Fallopian tube?
Simple columnar
What kind of epithelia exists on the ectocervix vs. endocervix?
Ecto = Stratified Squamous (ecto = "outside" like skin or vagina) Endo = Simple columnar
What are the 3 D’s of Pellagra (Niacin deficiency)?
Dementia, Dermatitis, Diarrhea
Vitamin A toxicity can cause _____
intracranial HTN, skin changes, and hepatosplenomegaly.
What kind of drugs can curb the development of tolerance to opioids?
NMDA receptor antagonists (ie ketamine) that block glutamate actions on the receptor. It is believed that activated NMDA receptors cause increasesd phosphorylation of opioid receptors and increased NO levels.
What chromosome is affected in Cystic Fibrosis?
Chromosome 7 - Autosomal Recessive
What are the chances that an unaffected individual (with unaffected parents) and one affected sibling with an autosomal recessive condition will be a carrier?
2/3. Because he or she is not homozygous, there are only 3 options.
What do the following findings indicate?
- JVD, tachycardia, hypotension, pulsus paradoxus
Cardiac tamponade
Which type of BPH treatment improves prostate volume?
5-alpha reducases like finasteride or dutasteride help reduce prostate volume, while alpha adrenergic antagonists only help to relax smooth muscle cells of the bladder neck. Alpha adrenergic antagonists and antimuscarinics do not reduce prostate volume
What is pancoast syndrome?
Caused by tumor in the lung apex, which can metastasize to superior sulcus and is characterized by:
- shoulder pain radiating to axilla and hand paresis due to lower brachial plexus involvement (C8, T1, T2)
- ipsilateral Horner’s syndrome
- Subclavian vessel compression -> upper ext edema
- Spinal cord compression if extensive enough
How would a Medium Chain acyl-CoA Dehydrogenase deficiency affect glucose and ketones?
Decrease both, especially after a period of starvation lasting 16-24 hours when peripheral tissues start relying on lipid-derived fuels. Deficiency leads to impaired beta-oxidation of fatty acids. (Saves glucose for organs that need it specifically). Induces severe hypoglycemia.
What is buspirone?
Buspirone is a 5HT1a agonist, and acts as tx for generalized anxiety disorder. It is safe and effective, but had weeks-long delay in onset of response. Does not cause dependence.
What should you be worried about if you see bilious vomiting in a few days old infant?
Sign of intestinal obstruction below duodenum, usually due to vascular accidents in utero. Can be major vessel occlusion (ie the SMA) that causes narrowing and obliteration of the lumen -> blind ending jejunum.
What must be true for a naked RNA to be able to induce viral protein synthesis when introduced to a host cell?
The viral RNA must be single-stranded and positive sense in order to use the host’s intracellular machinery for translation. Only SSRNA+ are infective.
What two microbes cause PID?
Neisseria gonorrhoeae and Chlamydia trachomatis.
Severe PID is known to increase the risk of ________ by 50%.
ectopic pregnancy
What is the chloride shift?
In RBC in venous blood, CO2 is taken up from the tissues and is coverted to Carbonic acid by carbonic anhydrase. It spontaneously converts to H+ and bicarbonate, which diffuses freely into plasma. To maintain electrical neutrality, Chloride enters RBC and causes the chloride shift in the venous blood.
What is spectrin?
Gives RBCs cell flexibility
What is the mechanism of action of benzodiazepines?
GABAa receptor-chloride channel binder that increases the frequency of opening of Cl- channels, which hyperpolarizes/stabilizes the membrane (rendering it less excitable).
Sedative hypnotic with anxiolytic, muscle relaxant, and anticonvulant actions.
Where is the complement binding region located on IgG and IgM?
Fc receptor on heavy Ig chain region, closer to the hinge point.
IgM circulates in pentameric form, and is thus a much better activator of complement.
What is the drug used in medical abortion?
Mifepristone, which is a progesterone antagonist. Used with a prostaglandin-E1 analog, Misoprostol.
In addition to ceftriaxone, what should you give to an infant with suspected meningitis?
Ampicillin to cover Listeria.
CTX covers Neisseria meningitidis, Strep Pneumo, Strep B, H Flu B.
Where is epinephrine chiefly producted?
Adrenal glands, by conversion of NE to E, utilizing the Phenylethanolamin-N-Methyltransferase enzyme. (Cortisol increases the synthesis of this enzyme.)
Prostacyclins ___________ platelet aggregation.
Inhibits.
Produces in vascular endothelia. It vasodilates, increases vascular permeability, inhibits platelet aggregation. Oppose TXA2.
What is a 95% confidence interval?
It is the range of values in which one can be 95% confident that the true mean of the underlying population falls.
Calculate by Mean +/- [1.96 x SD / (n^1/2)]
What gene is affected in Huntington Disease?
Chromosome 4, with increased # of CAG repeats
What is tetrabiopterin (BH4) used for?
Cofactor used by hydroxylases in the synthesis of tyrosine, dopa, serotonin, and NO. 5HT is made from tryptophan, and its initial step is catalyzed by an enzyme that uses BH4 as a cofactor. Deficiency in dihydrobiopterin reductase uncommonly causes PKU.
How do you detect a neural tube defect in utero?
Amniocentesis and check for Alpha-fetoprotein and ACE in the amniotic fluid,
What is Hirschprung’s Disease?
Failure of neural crest migration into the intestinal wall –> absence of myenteric and submucosal plexi in colon.
What is the most common presentation of cerebral amyloid angiopathy?
Recurrent hemorrhagic stroke, usually in lobar and in cerebral hemispheres and involving smaller areas of brain parenchyma (vs. HTN hemorrhagic strokes are larger and involve basal ganglia.
Name genetic diseases that arise from partial deletions.
Cri-du-chat (5p deletion), Prader-Willi (15q deletion), Angelman (15q deletion) syndromes
What is reaction formation?
Behavior pattern in which a person does the opposite of what he feels or desires. Usually a short-term immature response.
What is identification?
Refers to modeling one’s behavior after someone who is perceived to be more powerful.
What is the difference between repression and suppression?
Repression is a relatively thorough removal of disturbing psychological material from conscious awareness. Suppression is voluntary, conscious, and typically more temporary.
What kind of immune deficiency is seen in Ataxia-Telangiectasia?
IgA deficiency, primarily. Predisposes to infections of upper and lower airways.
Due to impaired DNA break repair (ATM gene)
What is Lesch-Nyhan syndrome?
X-linked recessive, defective gene for hypoxanthine-guanine phosphoribosyltransferase (HGPRT), which leads to severe hyperuricemia and gout. See patients exhibiting self-mutilating behavior, mental retardation, choreoathetoid movements, spasticity.
What disease causes defective sphingolipid degradation?
Niemann Pick disease, AR defect in sphingomyelinase –> accumulation of sphingomyelin within monocytes. Death in early childhood.
Hepatosplenomegaly, anema, motor neuropathy, cherry red spot on macula.
What is the major function of the ventromedial nucleus of the HTH?
Mediates satiety, stimulated by leptin.
What is the major function of the posterior nucleus of the HTH?
Mediates heat conservation, sympathetics
What is the major function of the anterior nucleus of the HTH?
Heat dissipation; pArasympathetics.
What is the major function of the lateral nucleus of the HTH?
Mediates hunger, inhibited by leptin.
What is the major function of the arcuate nucleus of the HTH?
Dopamine secretion, GHRH, and gonadotropins.
What is the major function of the paraventricular nucleus of the HTH?
ADH, CRH, Oxytocin, Thyrotropin-releasing hormone secretion
What is the major function of the supraoptic nucleus of the HTH?
ADH, oxytocin secretion
What is the major function of the suprachiasmatic nucleus of the HTH?
Circadian rhythms regulation and pineal gland function.
What do topoisomerases do?
Relieve unwinding tension caused by helicases in DNA replication.
What removes RNA primers in DNA replication of bacteria?
DNA pol I is the only bacterial DNA pol with 5’ to 3’ exonuclease activity (works in both excision repair and RNA primer removal).
What toxin can cause a defect in the release of GABA or Glycine?
tetanus toxin - resulting in muscle spasms, spastic paralysis, and hyperreflexia
What does polymixin cover?
Gram negatives
What does the Thayer-Martin selective medium grow, and what is in it?
Isolates Neisseria species. Contains vancomycin, polymixin (colistin), nystatin (fungi, yeast), and trimethoprim (gram negatives other than neisseria, ie proteus)
PCP is most likely to induce _____________, leading to mortality.
violent behavior/trauma
What CN is affected in vertical diplopia? (AKA, what is the most common cause of vertical diplopia?)
Trochlear nerve (CN IV)
Sometimes oculomotor nerve too.
A vascular lesion of the ___ and ___ nuclei of the thalamus can lead to complete contralateral sensory loss.
VPL (extremities) and VPM (face)
What would a lesion in the internal capsule cause?
Contralateral motor deficit.
What is the major cause of lacunar infarcts?
Occlusion of small penetrating arteries supplying deep brain structures, usually caused by lipohyalinosis and microatheromas, as a result of uncontrolled HTN or DM.
What is sublimation?
Mature defense mechanisms involving channeling an unacceptable impulse into an acceptable form of behavior. (ie patient with sexually explicit thoughts becomes a sex therapist)
Irritation of the ______ nerve can cause dyspnea and hiccups.
Phrenic (C3-C5) nerve, which supplies the ipsi hemidiaphragm.
SVC syndrome usually is associated with ___________ .
SCC of the lung (centrally located)
What is a Wilms tumor?
nephroblastoma in 2-4yr olds, presents with palpable flank mass.
_______________ can cause opsoclonus-myoclonus.
Neuroblastoma – increased N-myc genes, most common extracranial neoplasm in children. Has associated paraneoplastic syndromes like opsoclonus-myoclonus.
The parietal cortex is important in integrating ________ information.
Sensory
Destruction of the subthalamic nucleus can lead to ___________.
Hemiballism (involuntary flinging movements of extremities, contralateral to lesion).
How does Pick’s disease present?
Atrophy of frontal lobe – manifests as dementia, behavioral disinhibition, speech difficulties
What is Fragile X syndrome?
Increased number of trinucleotide repeats CGG in the familiar mental retardation gene, located on the long arm of the X-chromosome (appears as a gap since the repeat doesn’t stain well). 2nd most common cause of mental retardation.
How does Fragile X present?
Mental retardation, macrosomia, large jaw/ears/forehead, long/thin face, macroorchidism.
Short stature, broad chest, webbed neck, and low hair line are signs of ___________.
Turner’s syndrome (45 XO)
Klinefelter syndrome has the karyotype:
47 XXY, affects only males.
Tall, gynecomastia, small firm testes, infertility (due to low testosterone)
What kind of hypersensitivity reaction is involved in Erythroblastosis fetalis?
Type II – Maternal Ab IgG formed against fetal erythrocytes.
What are 3 possible causes of intestinal B12 malabsorption?
pancreatic insufficiency, intestinal bacterial overgrowth, ileal disease (if not dietary nor IF deficient) – Can tell through Schilling test with radiolabelled B12/test urine output. Then, add IF with RA B12 to see if it’s due to an IF deficiency.
Cladribine is a _______________, resistant to adenosine deaminase and is used to treat __________________.
Purine analog, hairy cell leukemia.
What is the purpose of thehexose monophosphate (HMP) shunt?
- To produce NADPH as a reducing equivalent, to maintain glutathione in a reduced state so that it protects erythrocytes from oxidative damage. Only process that makes NADPH in the erythrocyte.
- The synthesis of ribose 5-phosphate for nucleotide synthesis.
What drug has oxidant properties and can precipitate hemolysis in a patient with G6PD disease?
Bactrim for UTIs.
What is the inheritance pattern of G6PD disease?
X-linked recessive.
What is paroxysmal nocturnal hemoglobinuria?
Mutation in GPI anchor of DAF (CD55) and CD59, which are cell-surface proteins that inactivate complement and protect the cell.
- Hemolytic anemia
- Hypercoag state (thrombosis is common cause of death)
- Decreased blood counts
CD55 and CD59 protein deficiency is diagnostic of ________.
paroxysmal nocturnal hemoglobinuria.
The major clinical manifestation of factor V Leiden is ______.
DVT, cerebral vein thrombosis, and recurrent pregnancy loss.
What is Methotrexate?
A folic acid analog that functions by binding and inactivating DHR, which reduces folate to THF. Inhibit thymidylate formation. Can be rescued by leucovorin, but 5FU cannot be rescued.
What is gemcitabine and cytarabine?
Pyrimidine analog antimetabolites
DNA damage from exposure to UV radiation leads to formation of ____________.
pyrimidine dimers (thymine dimers)
Vinca alkaloids are _______ phase-specific agents.
M-phase, because they prevent MT formation during mitotic spindle formation. Cannot align and segregate daughter chromosomes during mitosis.
Mercaptopurine is _______ phase specific
S-phase. Purine analog, associated with cholestatis and hepatitis.
What are androgen’s effect on RBC production?
Enhances - that’s why males have higher Hematocrit.
.The most common type of childhood neoplasm is __________
leukemia, (second is brain tumors like pilocytic astrocytomas)
What are medulloblastomas?
High grade, malignant brain tumor of childhood, usually in vermis, solid, sheets of small blue cells with hyperchromatic nuclei and scant cytosol. Causes severe HA and cerebellar dysfunction.
What is heteroplasmy?
Mixture of two type of genetic material, and is responsible for the clinical variability of mitochondrial diseases, like MELAS. (Daughter cells split mitochondria randomly during mitosis)
What syndrome causes immunodeficiency, albinism, and neurological defects like horizontal nystagmus?
Chediak-Higashi Syndrome, an AR disease, causes neuropathies, immunodeficiency from a defect in phagosome-lysosome fusion, and abnormal melanin storage.
What is DiGeorge’s Syndrome?
Failure of formation of 3rd and 4th branchial arches due to mutation on Ch22, causing immunodeficiency - thymic and parathyroid hypoplasia. (recurrent infections).
What is the Wiskott-Aldrich syndrome?
X-linked, immunodeficiency (B and T cell), eczema, and thrombocytopenia.
What is the metanephric diverticulum?
Ureteric bud – sprouts off the caudal portion of mesonephric duct; gives rise to collecting tubules and ducts, major and minor calyces, renal pelvis, and ureters.
Induces the formation of the metanephric mesoderm (gives rise to glomeruli, Bowmans space, PCT, loop of Henle, and DCT) with reciprocal exchange of inductive signals.
A decrease in _______ will cause achlorhydria.
gastrin
What kind of organisms have N-acetylmuramic acid and N-acetylglucosamine in the cell well?
Gram+ and Gram- organisms
What is alpha-1-antitrypsin?
Serum protein that inhibits several different proteolytic enzymes, especially neutrophil elastase and reduces inflammation.
Deficiency can cause panacinar emphysema or cirrhosis. Think about this in patients with early onset of chronic bronchitis, emphysema, as well as nonsmokers with chronic obstructive pulmonary disease.
Anthracycline chemotherapy is cardiotoxic and can cause ___________.
Dilated cardiomyopathy.
Hemochromatosis, amyloidosis, and sarcoidosis can cause what kind of cardiomyopathy?
Restrictive.
K+ depletion stimulates what kind of cells to reabsorb extra K?
Alpha-intercalated cells in the kidney’s late distal and cortical collecting tubules. Principal cells secrete K under conditions of normal or increased K load.
The Posterior Cruciate Ligament attaches to what?
Attaches posteriorly to the intercondylar area of the tibia and the anterior LATERAL surface of the medial epicondyle of the femur. (ACL attaches medially to the posterior of the lateral femoral condyle.)
The deep peroneal nerve innervates what parts of the foot?
The extensors and the great dorsiflexors.
Prolonged compression can cause foot drop. Comes from the common peroneal, which is easy to injure because it lies at the lateral neck of the fibula.
Damage to what nerve will cause loss of ability to plantarflex?
Tibial nerve.
Damage to what nerve causes wrist drop?
Radial nerve.
What is a demyelinating syndrome of peripheral nerves, characterized by ascending muscle weakness and paralysis?
Guillain-Barre Syndrome.
Can be attributable to Campy infection in 10-30% of cases.
Immunity to reinfection for influenza type A relies on what kind of antibodies?
Adaptive immunity: specific anti-hemagglutinin IgA (nasopharynx) and IgG (serum) antibodies.
What kind of picornavirus is acid-labile?
Rhinovirus
The enteroviruses are acid-stable. ie Coxsackie A, Echovirus, Poliovirus, Hep A
What drug can be used to treat essential tremor?
Propranolol, a beta-adrenergic antagonist.
What is the pattern of inheritance for essential tremor?
For the familial kind, AD.
What is the filtration fraction?
The ratio of GFR to Renal Plasma Flow = GFR/RPF
Normally, 1/5 of the plasma that passes through the glomerular capillaries is filtered into the bowman’s capsule.
Where does synthesis of steroid hormones and drug detoxification occur?
SER
What do eplenerone and spironolactone treat?
These are aldosterone antagonists, used for Conn’s syndrome treatment (aldosterone-secreting adenoma) or for hypertension.
What is the site of action for aminoglycosides?
30S ribosomal subunit.
Unlike loop diuretics, thiazides can cause hyper________.
Hypercalcemia.
All protease inhibitors, as part of HAART therapy, can cause these adverse effects:
Lipodystrophy (buffalo hump), hyperglycemia (increased insulin resistance), P450 inhibition.
Indinavir is a protease inhibitor that can cause specific side effects such as ______________.
Nephrotoxicity and nephrolithiasis.
What is Pemphigus Vulgaris?
Autoimmune disorder with Ab against Desmogleins 1 and 3 (desmosomal), causing painful, flaccis bullae and skin erosions that spread laterally upon pressure (asboe-hansen sign) and form new bullae with gentle traction (Nikolsky sign).
What disease is characterized by autoantibodies against hemidesmosomal proteins?
Bullous pemphigoid
What are the three cardinal findings in Wiskott-Aldrich syndrome?
- Eczema, 2. Recurrent Infections of encapsulated organisms (B and T cell disorder), 3. Thrombocytopenia.
X-linked.
What drug should you use to mitigate the effects of cisplatin therapy?
Amifostine is a cytoprotective free-radical scavenging agent used to decrease the cumulative nephrotoxicity associated with platinum-containing agents, which form reactive oxygen species that can form DNA crosslinks.
What is the name of a G-CSF analog used to stimulate the proliferation and differentiation of granulocytes?
Filgrastim.
What is fomepizole?
Antidote in rubbing alcohol or antifreeze (ethylene glycol) poisoning, through competitively antagonizing alcohol dehydrogenase. Prevents conversion into toxic metabolites.
What can you use to mitigate the effects of doxorubicin or other anthracyclines?
Dexrazoxane is an iron chelating agent that can help prevent cardiotoxicity and CHF.
Unlike LMWH, unfractionated heparin can bind to both _______ and __________.
Antithrombin and thrombin
Dysphagia in a patient with iron-deficiency anemia and spoon nails is suspect for __________.
Plummer-Vinson syndrome and esophageal webs.
Kozak consensus sequence occurs on mRNA with ___ or ___, three bases before a start codon like AUG.
Adenine and Guanine
Mutation in this position is associated with thalassemia intermedia.
Basophilic stippling can occur in what condition?
Lead poisoning – stippling on a background of hypochromic microcytic anemia, on peripheral blood smear.
How are wet and dry age-related macular degeneration (AMD) different?
Wet: abnormal blood vessels with subretinal hemorrhage/fluid, gray subretinal membrane. Treat with Anti-VEGF.
Dry: subretinal drusen deposits or pigment changes. Dry progresses to wet usually.
EGFR inhibitors like erlotinib and gefitinib are used for what kind of cancers?
non-small lung cell cancer.
What is the structure of the Parvovirus?
Parvoviruses, like B19, are single-stranded DNA viruses with no envelope.
What is the major cause of aplastic crisis in sicklers?
Parvovirus B19
Why are sicklers prone to megaloblastic anemia?
Sicklers get folate deficiency from rapid turnover of erythrocytes. Folate amounts cannot keep up with DNA synthesis and impair its process, so cells divide slowly and end up larger than normal.
How do pufferfish cause poisoning?
Release tetrodotoxin, a neurotoxin that binds to voltage gated sodium channels in nerve and cardiac tissue, preventing sodium influx and depolarization.
When symptoms of schizophrenia are present for a period of 1-6 months, ____________ disorder is the diagnosis
schizophreniform. >6 mos: schizophrenia
30-50% of schizophreniform patients will NOT develop schizophrenia
What is acting out?
Immature defense mechanism, in which one avoids unacceptable feelings by behaving badly. ie throwing a tantrum
What is displacement?
Immature defense mechanism – transferring feelings to a more acceptable object,
What is projection?
Immature defense mechanism, in which one attributes one’s own feelings to others.
