Random Missed Uworld - Week 4 Flashcards

Question

What are the different phases where ovum development is arrested?

Answer 1

Female gametogenesis begins in utero at ~4 weeks gestation when primordial germ cells migrate from teh yolk sac region to the developing gonadal region - tehse germ cells then differentiate into oogonia and multiply by mitosis before begining meiosis I --\> Primary oocytes Primary oocytes are competely developed in female embryos by the 5th month of gestation, at which point they are arrested in PROPHASE of MEIOSIS I, remain here until ovulation Normal mentrual cycle hormoens stimulate the primary oocyte to resume differentiation --\> during each menstrual cycle, FSH stimulation follwed by an LH surg causes some oocytes to resume meiosis I--\> secondary oocytes....the secondary oocytes begins meiosis II but halts....36 hours after LH levels being to rise, secondary oocyte is released from the ovarian follicle ....prior to fertilization, secondary oocytes are arrested in METAPHASE of MEIOSIS II...until fertilization in which it completes its division into a mature oocyte/ovum (and second polary body).

Answer 2

wallerian degeneration occurs in teh segment of axon that has lost connection with the cell body - it represents the degeneration of axon and myelin distal to the point of injury: 1- swelling and irregularity are noted in the distal segment of the axon 2 - axon is destroyed within a week and fragments digested by schwann cells and macrophages Similar degenerative changes occur in teh seg of axon that lies proximal to the injury -- extends to the closest node of ranvier. Changes seen in the neuronal body after the axon is severed are called axonal reaction. 1. cell body shows signs of cellular edema, becomes swollen and rounded, with the nucleus displaced to the periphery 2. Nissl substance becomes fin, granular and dispered throughout the cytoplasm (central chromatolysis) becomes visible 24-48 hours after the injury; maximal chianges in teh neuronal body occur apx 12 days after the injry - reflect an increased synthesis of protein by the cells in order to regenerate the severed axon

Answer 3

Succinylcholine is a depolarizing neuromuscular-blocking agent that like acetylcholine attaches to the nicotinic acetylchonie receptor and depolarizes the NM end plate; not degraded by acetylcholinesterase --\> continuous stimulation of the endplate (initial transiet fasciculations) --\> inactivate sodium channels and cannot reopen until the end plate is repolarized remaines isolated to the end plate resulting in development of flaccid paralysis (phase 1 block) -- evetually with continuous administration, the continuous depolarization of the end plate gives way to gradula repolarization as the nAChR becomes desensitized to the effects of succinylcholine --\> phase II block, similar to non-depolarizing blokade. Malignant hyperthermia (esp with halothane) in genetically susceptible pt Severe hyperkalemia in pt with burns, myopathies, crush injuries and denervation (because of upregulation of muscle nAChRs Bradycardia from parasympathetic stimulaiton or tachycardia from sympathetic effects

Answer 4

The proximal tubule reabsorbs \>60% of the water filtered by the glomeruli, regardless of the patient's hydration status. This water is absorbed isosmotically with solutes. NO concentration or dilution of the urine occurs in this segment In dehydrated state: plasma osmo increases, ADH is released, allowing for improved water permeability in teh collecting ducts, allowing production of maximally concentrated urine (osmo 1200) No water is reabsorbed in cortical collecting duct, distal tubule or medullary collecting duct in overhydrated state; up to 20% of original filtered urine can be reabsorbed with ADH in dehydrated state Descending loop of henle absorbes about 20% of filtered water \*\* highest osmolarity at the bottom of the loop of henle!

Answer 5

Decreases intestinal absorption of cholesterol by inhibiting the Niemann-Pick C1-like 1 transporter protein, which transports dietary cholesterol from teh GI lumen into teh intestinal enterocytes -- less cholesterol reaches teh liver, lowering intrahepatic cholesterol levels --\> liver increases LDL receptor expression, whcih draws cholesterol out of circulation

Answer 6

originates from teh anterior surface of the transvers processes and lateral surface of the vertebral bodies at T12 - L5 Inferiorly (at around the level of the inferior ligament), the psoas muscle combines with the iliacus muscle --\> iliospoas muscle, which functions with hip flexion, also contributes somewhat to lateral rotation and abduction of the thigh \*HIV, IV drug use and diabetes are risk factors for primary psoas abscess development

Answer 7

Coag-neg staph staph aureus enterococci candida spp monitor for new-onset fever or bacteremia first-gen cephalosproin used as it provides good coverage agasint much of the normal skin flora.

Answer 8

Chronic alcohol users are malnourished and have low levels of thiamine at baselin. IV dextrose admin withouth prior thiamine supplementaiton in these patietns results in an acute drop of thiamine levesl --\> wernicke encephalopathy Clincal pres: ataxia, nystagmus, opthamoplegia, anterograde amnesia (CAN - confusion, ataxia nystagmus) Chronic effects of thiamine deficiency can lead to Korsakoff psychosis = anterograde and retrograde amnesia, apathy, lack of insight and confabulation \*Thiamine is a key coenzyme for pyruvate dehydrogenase, which is invovled in glucose metabolism -- thus deficiency results in the brains inability to metabolize glucose --\> energy Teh structure of the brain that most frequently undergoes necrosis in the setting of thiamine deficiency is the mammillary body ( part of the papez circuit, which is a neural pathway of the limbic sys tha tis invoved in teh cortical control of emotion and meory)

Answer 9

1. Anti-convulsants that induce CYP 450 (phenobarbital, phenytoin, carbamazepine) 2. Aromatase inhibitors 3. Medroxyprogesterone 4. GnRH agonist (dec T and E) 5. Proton pump inhibitors (dec calcium absorption- insoluble calcium req an acidic environment for proper absorption and acid-suppressing meds can interfer with the process) 6. Glucocorticoids 7. Unfractionated heparin 8. Thiazolidinediones

Answer 10

System begins with ligand-receptor binding and Gq protein activation leading to activation of phospholipase C (PLC). PLC then hydrolyzes phosphatidyl inositol bisphosphate and froms diacylglycerol and inositol triphosphate IP3. Finally, IP3 activates protein kinase C via an increase in intraceullar calcium

Answer 11

avascular necrosis of the bone due to impaired blood supply to a segment of bone. The femoral head is the most common location, although other bones may be affected Associated conditions: 1. SCD leads to thormbotic occlusions of arteries, embolic occlusions (fat emboli, decompression sickness) can also cause osteonecrosis 2. injury to the vessel wall, vasculitis, causes impaired blood supply (sle) 3. high dose corticosteriod therapy and alcoholism are also associated with ostenecrosis of the femoral heald although the mechanism is unknow presents iwth chronic, progressive groin and hip pain that is exacerbated by wt bearing. Physical examinaiton reelas restricted movement in teh affected joint with no swelling, erythema or warmth in the surroudnign area. Microscopic analysis of the wedge shaped zone of the affected bone is notable for dead bony trabeculae/empty lacuna and fat necoriss

Answer 12

Peritubular cells in teh renal cortex sense hypoxia and respon by releasing erythropoietin into the bloodstream (deficient erythropoietin production is the reason why many pt with chronic kidney disease develop anemia) Erythro --\> stimualtes erythrocyte production by binding erythro R on erythrocyte precursors in the bone marrow; this response is secondary polycythemia that occurs in pt with chronic hypoxia secondary to: OSA, COPD, R-to-L shunts and high altitude [LIVER is major site of erythropoietin production in teh FETUS!]

Answer 13

branch of hte mdial cord of the brachial pleuxs (C8-T1), that courses posteromedially in the upper arm Then passes posterior to the medial epicondyle of the humerous to enter the anterior compartment of the forearm -- it innervates the flexor carpi ulnaris and the medial portion of the flexor digitorum profundus At the wrist, nerve passes between the hook of hte hamate and the pisiform bone within Guyon's canal -- then divides into the superficial branch that provdies sensation over the medial 1.5 digits and ypothenar eminence and a deep motor branch that supplies most of the intrisic muscles of hte nad Ulnar nerve is the most commonly injured at the elbow - funny bone due to trauma (eg medial epicondyle fracutre) or nerve compression (resting on a hard surface) -- presents with loss of sensation/parethesia in the ulnar distribution. Severe cases can result in weakness of wrist flexion/adduction, finger abduction/adduction and flexion of the 4th and 5th digits weakness of lumbricals in teh 4th and 5th fingeres may produce ulnar claw hand deformity during finger extension

Answer 14

Rapidly Progressive Glomeurlonephritis LM: **_crescent_** moon shape (diagnostic!!) IF: **_firbin_** and plasma proteins (C3..) \* Deposition of FIBRIN is essential pathologic step in crescent formation \*Crescent in RPGN consists of proliferated glomerula parietal cells, monocytes and macrophages that have migrated into Bowman's space + abundant fibrin between the cellular layers of the cresants \*Dz progression: cresants become sclerotic and oblierate Bowman's space --\> decreasing glomerular function Bad prognosis This could have been a complication of several disease processes include: Goodpastures, Granulomatosis with polyangiits (Wegners) and microscopic polyangiits

Answer 15

macrophages and T cells pass through the gaps into Bowman's space --\> leakage of fibrin into the space as welll --\> damage to glomerular capillaries casues gaps to form in the basement membrane Promientn fibrin deposition leads to proliferation of parietal cells Macrophages secrete factors that enhance fibrin deposition, cellular proliferation and fibrosis Recruitment of interstitial fibroblast that proliferate and secrete collage

Answer 16

True - contains all three parts of the intestinal wall: mucosa, submucosa and muscularis False- contains only the mucosa and submucosa; usually herniation through defects in the muscular layer; exacmples: Colonic and Zenker (upper esopho) are examples of false/pulsion diverticula. Meckel's is a TRUE diverticular (rule of 2's) -during early embryogen, the lumen of the midgut and yolk sac cavity are connected via the omphalomesenteric/vitelline duct, which should obilerate during the 7th week of fetal life; partial failure of this duct to oblierate --\> Meckel's. \*recall that Mecke's diver, could contain ectopic tissue (gastric being the most common, second to pancreatic) which can lead to increased gastric acid = ulceration of adjacent mucosa and lower GI bleed (melena/hematochezia)

Answer 17

Ventricular premature beats, V.Tac, VFib Common in the first 24-48 hours after MI premature or nonstustain arrhythmias do not req. specific therapy vs sustained and recurrent arrythimias are often managed with antiarrhythmic drugs Drug of choice: **AMIODARONE**, **lidocaine** (2nd)

Answer 18

Weakest sodium channel blockers, dissociate the fastest Negligle effect on QRS duration in normal cardiac tissue Predom bind to sodium channels in their inactivated state Since ishcemic myocardium has higher than normal resting membrane potential (delaying VG-recovery of sodium channels from their inactivated to resting state), this allows binding of 1B agents to be highly efficacious in **inhibiting ischemia-induced ventricular arrythmias**

Answer 19

Primary hyperparathyroidism --\> hypercalciuria Crohns Disease --\> hyperoxaluria Distal Renta Tubular Necrosis --\> hypocitraturia Gout --\> hyperuricosuria \*\***Urine supersaturation**- main reason for underlying renal stone formation\*\* **Low fluid** (dehydration), low calcium, high oxalate (spinach, rhubarb), high protein, high sodium, high fructose \*\*Calcium stones (ca-oxalate \> ca-phosphate) account for 70-80% of all renal stones

Answer 20

**Sirolimus** - proliferation signal inhibitor; bin_ds to the immunophilin FK506 binding protein_, forming a complex that **inhibits mTOR --\> interruption of IL2** signal transduction, *_preventing G1 to S phase progression*_ _*and lymphocyte proliferation_* **Daclizumab, basiliximab** - monoantibodies that block IL2R

Answer 21

Caused by volatilization of amines produced by G vaginalis and other anaerobes BV treatment: metronixazole and clindamycin

Answer 22

INC alpha-fetoprotein levels is a typical presentation of HCC, strongl associated with HBV infection It is thought that the integration of viral DNA into the cellular genome of the host is what triggers neoplastic change from HBV infection --\> HCC viral protein HBx activates teh syntehsis of insulin-like frowth factor II and receptors for insulin like-growth facto I --\> stimulating cell proliferation HBV gene products also suppress p53 tumor suppressor / cell cycle regulatory gene in host cells Chronic inflammation adn regeneration induced by HBV infection also can facilitate accumulation of mutations in hepatocytes leading to carcinogeneis ALL THESE EVENTS RESULT FROM INTEGRATIN OF THE VIRAL GENOME INTO HOST CELL

Answer 23

**Pyruvate Kinase is the enzyme used in glycolysis to convert phosphoenolypyruvate to pyruvate --\> ATP** production (since mature RBC do not contain mitochondria, rely on lactate as their main metabolite for glycolysis) Most ATP produced is used for the transport of cations against a concentration gradient in the RBC A **deficiency in pyruvate kinase** --\> **insufficient ATP production** --\> disruption of the gradient --\> water and potassium loss --\> defective maintenance of membrane architecture/**echinocyte formation and hemolysis** Reticuloendothelial cells in the **splenic red pulp** are invovled in teh removal of damanged RBCs--\> there needs to be an increase in their activty --\> **hyperplasia** and **splenomegaly**!

Answer 24

Pus = thin, protein-rich fluid known as liquor puris, **dead leukocytes, primarily neutrophils** during an infection, macrophages and surrouding endothelial cells release cytokines such as **IL8 t**hat **trigger neutrophil to enter the site of infection via chemotaxis** **IL 8 also induces phagocytosis in neutrophils once they have arrived** *Other significant chemotaxic agents = n-formylated peptides, leukotrienes B4, 5-HETE (lekotriene precursor) and complement component C5a (NOT C3a- which recruits and activate eosinohpils and basophils but not neutrophils!)*

Answer 25

leads to an increase in parasympathetic tone causing temp inhibition of SA node activity --\> slowing of conduction through the AV node --\> prolongation of the AVe node refractory period. It is useful vagal maneuver for the termination of paroxysmal supraventricular tachycardia (and decrease systemic vascular resistance) Other vagal maneuvers - valsalva, cold water immersion; all can be used to acutely terminate PSVT (likely due to reentrant impulse treavleing circularly btw slow and rapid conducting segments of teh AV node) When it does NOT function -

Answer 26

NE = adrenergic agonist mostly affects alpha 1, alpha 2 and beta 1 receptors (hardly beta2) "qiss" Alpha 1 --\> increase IP3 --\> peripheral vasoconstriction of skin and viscera --\> inc in systolic and diastolic BP with decrease in renal and hepatic blood flow Alpha 2 --\> decrease in cAMP --\> dec release of NE and insulin Beta 1 --\> increase in cAMP via Gs --\> increased contractility --\> increased cardiac contractility, conduction and heart rate (positive chronotropic effect) BUT the HR is opposed by baroreceptor-mediated refelx bradycardia that occurs following the increase in peripheral resistance --\> unchanged HR or slight decrease

Answer 27

Somatic Symptom disroder is excessive anxiety and preoccupation with one or more unexplained symptoms Conversion disorder (aka- functional neurological symptom disorder) is **neurologic** symptom incompatible with any known neurologic disease; often acute onset associated wtih stress. It is a type of somatic symptom disrer b tit is specifcially characterized by symptoms or deficits of voluntary motor and or sensory function that are INCOMPATIBLE with any recognized neurological condition, cannot be explained by another medical or mental disorder

Answer 28

Pt with recurrent episdoes of abdominal pain, episodes of facial swelling --\> angioedema due to C1 inhibitor deficiency (C1INH) C1INH prevents C1-mediates cleave of C2 and C4, thereby limiting the activation of complement cascade It also **blocks kallikrein-induced conversion of kininogen to bradykinin**, a *_potent vasodilator that also causes increased vascular permeability (--\> bradykinin-associated angioedema)_* _*sx:* facial swelling without urticaria, life-threatening laryngeal edema and GI manifestations (n/v, colicky pain, diarrhea)_ _Managemetn of acute attackes invoveld supportive care and the administration of C1INH concetrate or a kallikrein inhibitor_

Answer 29

depression, fatigue, hypersomnia, hyperphagia, vivid dreams, intense psychomotor retardation, "crash" There are no significant physical findings with cocaine withdrawals (no change to eyes, seizures, HR...) that is in contrast to opiates (dialted pupils, yawning, piloerection, lacrimation, hyperactive bowel sounds), and alcohol + benzos (seizures, tachycardia, palpitaitons)

Answer 30

ENV envelop glycoprotein **gp350 binds to CD21** (aka **CR2**), the cellular receptor for **C3d complement component**. CD21 is normally present on the *_surface of B cells (CD19-positive cells) and nasopharyngeal epithelial cells_*

Answer 31

Hepatitis D = Delta agent 35nm double-shelled particle that resembles teh Dane particle of hepatitis B (HBV) internal polype assembly of HDV is designated hepatitis D antigen, associated with this antigen is a very short, circular molecule of SS RNA HDAg is considered replication defective as it must be coated by the external coat hepatitis B surface antigen of HBV to penetrate the hepatocyte; HBV helps coat the viral particles --\> HDV infection can arise either as an acute co-infection with HBV or as a superinfection of a chronic HBV carrier (super is worse!) **\*\*the Hep B surface antigen of HBV must coat the hep D antigen of HDV before it can infect hepatocytes and multiply.**

Answer 32

HF results in stimulation of the sympathetic NS and teh RAAS in an attempt to maintain effective intravascular volume -- inactive angiotensin I is converted into active angiotensin II by endothelial bound ACE in the lungs (predominately the pulmonary vasculature!!)

Answer 33

Base of pons - contalateral weakness, ataxia due to involvement of descending motor tracts and pontocerebellar fibers Caudate nucleus - behaviorn abnormalities, speech/language disturbances and movement disorders Frontal cortex - social disinhibition and deficts in attention, executive function Posterior limb of the internal capsule- anterior 2/3 of the posterior lim is mainly composed of motor fibers, psoterior 1/3 contains sensory - rare for it to be soley sensory;more common a combined sensorimotor deficit Ventral posterior thalamus - hemisensory loss usually is from a thalamic stroke; VPL receives input from teh STT and DCT, and the ventral posterior medial nucleus [damage may result in complete contralateral sensory loss; severe proprioceptive defects may cause unsteady gait]

Answer 34

Lacunes are small cavitary infarcts located within the basal ganglia, posterior limb of hte internal capsule, pons and cerebellum. The infarcts result from occlusion of the small penetrating arteries that supply these deep brain structures (leticulostriate arteries), most commonly in the setting of chronic uncontrolled HTN or diabetes **lipohyalinosis** and **microatheromas** are believed to be the primary cause of lacunar infarcts Lipohyalinosis - secondary to leakage of plasma proteins through damaged endothelium and is characterized by hyaline thickening of the vascular wall, collageous sclerosis and accumulaiton of mural foamy macrophages Microatheromas result from atheroscleorotic accumulation of lipid-laden macrophages within the intimal layer of a penetrating artery near its origin of the presnte vessel These changes predispose to small vessel occlusion adn infarciton of CNS with liquefactive necrosis and the formation of a fluid-filled vacity

Answer 35

Missense mutaitons are characterized by base substituations that result in the placement of an incorrect AA in the protein sequence - these mutations occur within the coding region of a gene and affect protein translation. The mRNA transcription seize would be unaffected, so the mRNA template would be normal in length Nonsense mutations introduce a premature stop codon within the coding region --\> formation of truncated proteins. A nonsense mutation would not alter the mRNA size though as it only affects protien translation and not transcription. \*\*careful in whether they are talking about transcription/mRNA or tranlsation/protein production

Answer 36

form of non-coding RNA, specific tRNA transfer certain AA residues to the growth polypeptide during translation tRNA functions by recognizing the 3 base codon on the mRNA being translated through its anticodon region, which contains the complementary bases; the secondary structure of tNA resembles a cloverleat that contains- acceptor stem (5' termina to 3' termiina NT that includes a CCA tail with the amino acid bound to the 3' terminal hydroxyl group when teh tRNA is loaded with the appropriate AAA by aminoacy tRNA synthase 3'CCA tail is added posttranscriptionally, helpes to recognize as tRNA molecule; serves as teh amino acid binidng site! aminoacyl tRNA synthetase is the enzyme responsible for "loading" the appropriate amino acid to the 3' terminal hydroxyl group of the CCA tail

Answer 37

Night blindness!! Severe eye dryness adn CORNEAL ULCERATION keratinization of the skin growth retardation immune impairment causes: insufficient dietary intake, pancreatic insufficiency (chronic pancreatitis, CF), cholestatic liver disease/biliary obstruction (PBC), intestinal malabsorption (inflammatory bowel disease, bariatric surgery, Crohn dz)

Answer 38

*_Acute:_* **Right ventricular failure** --\> hypotension, clear lungs, kussmaul sign *ventricular arrhythmias (Vfib) are the most common cause of sudden cardiac death within the first 48-72 hours after MI* *_Day 3-5:_* **Papillary muscle rupture** --\> acute, severe pulmonary edema; severe mitral regur with flail leaflet **Interventricular septum rupture/defect** -- new holosystolic murmu, stepped up oxygen level btw right atrium and ventricle *_Day 5-14:_* **free wall rupture** [sx: suddent onset of chest pain, profound shock and rapid progression to death; rupture appears as a slit-like tear in the infarcted myocardium with a preference for the left ventricle due to higher systolic pressures] hemopericardium and cardiac tamponade

Answer 39

Power of a study is the ability to detect a difference between groups when such a difference truly exists. Power is related to type II error (B) = probabilty of concluding there is no difference between groups when one truly exists Power = 1-B Type 1 error = probability of seeing a difference when tehre is no difference in reality.

Answer 40

*_Acute migraines_* --\> **TRIPTANS** = **serotonin 5HT1n/5HT1D agonist** used as abortive therapy during an acute migraine *_For prophylaxis_*: beta-blockers, anti-Ds (amitriptyline, venlafaxine) and anticonvulsants (valproate, topiramate) are common used for migraine prophylaxis

Answer 41

gastroduodenal artery This artery arises from teh common hepatic artery and perfused both the pylorus adn the proximal part of the duodenum @ the anterior of the dudoenum, an ulcer is more likely to perforate

Answer 42

Bioavailability = the fraction of administered drug that reaches teh systemic circulation in a chemically unchanged form. Bioavailability for a drug administered by a non-IV route is always less than 1. IT can be determined by examining a graph of plasma concentration versus time and then applyin the formula: **F= (AUC oral x dose IV) / (AUC IV X oral dose)** bioavailability for IV is 1. so you pust divide the AUC for whatever route by the bioavailability of the IV.

Answer 43

Anti-histone refers to drug induced lupus and anti-nuclear is also another either non-specific antibody or seen in SLE. (maybe anti-dsDNA but rarely seen since this is more specific for SLE) Clinical sx: abrupt onset symptoms - fever/fatigue, arthralgias/arthritis, rash, serositis \*predilection for slow acetylators Implicated drugs: SHIPPE Hydralazine Isoniazid Procainamide phenyotin etanercept (TNF-alpha inhibitors) Minocycline * usually clinical improvement is rapid on discontinuation of the caustive agent* * Procainamide, hydralaizine and isoniazid are metabolized via **phase II acetylation in the liver*** ***Patients that are slow acetylators are alos predisposed to isoniazid-induced peripheral neuropathy due to increased drug concentrations***

Answer 44

Risperidone is an anti-psychotic drug that is used in the management of schizophrenia. Its primary action is to inhibit dopamine D1 and D2 receptors and also inhibits serotonergic and alpha-adrenergic pathways Since the secretion of prolactin is controlled by the inhibitory effect of hypothalamic dopamine--\> drug induced hyperprolactinemia by blocking D2 receptors on lactotrophs. Elevated rolactin leads to amenorrhea (inhibition of GRHR), galactorrhea and breast soreness due to the loss of normal tonic ihbition of prolactin release by dopamine.

Answer 45

selective estrogen receptor modulators = competitively inhibit estrogen binding; mixed agonist/anatgonist action Tamoxifen -- adjuvant tx of breast CA; treatment for estrogen receptor- positive BCA Raloxifene -- + also postmenopausal osteoporosis; excellent for prevention AEs: hot flashes, venous thromboembolism, endometrial hyperplasia and CA (tamoxifen only)

Answer 46

Follicular lymphoma! majority exhibit t(14,18) overexpression of bcl-2 oncogene that blocks programmed cell death most common indolent non-hodgkins lymphoma in adults and second most common NHL overall

Answer 47

SMA leaves the aorta at L1...normally, the angle is about 45 degrees. If this angle is dimished to less than 20 degrees than teh TRANSVERSE portion of the duodenum can get entrapped between the SMA and aorta --\> sx of small bowel obstruction. This can occur with any condition that causes diminished mesenteric fat, including low body weight, recent weight loss, severe burns or other inducers of catabolism and prolonged bed rest It can also occur with pronounced lordosis or after surgical correction of scoliosis, as this procedure lengthes the spine resulting in decreased mobility of the SMA

Answer 48

sleep hygiene (reg sleep schedule, avoid naps, avoid caffeine after lungh, avoid alcohol smoking largem emals...adjust bedroom to enviornment, exercise regularly but not soon before bed) Stimulus control (only bed for sleep and sexual acvitivity!! if you can't sleep leave and go to another room; fixed wake up time including weekend) relaxation sleep resitriction

Answer 49

Periodic acid-schiff reaction is used in histochemical staining because the periodic acid oxidizes carbon-carbon bonds, forming aldehydes that produce a brilliant magenta color upon reacting with the fuchsin-sulfurous acid. Particuarly effective at highlighting polysac of the funal cell wall, mucosubstances secreted by epithelia, and basement membranes glycoprotein present in teh cell walss of gramp-positive actinomycete T. whippelii appears magenta + diastase-resistance

Answer 50

in 90% of individuals, the posterior inferior wall of the left ventricle is supplied by teh posterior descending branch of the right coronary artery. Bradycardia and resultatnt hypotension also suggest that there could be ischemic injury to the sinus node as well -- the sinus node is normally perfused by the RCA

Answer 51

ST elevations in leads II, III, AVF? RCA, transmural ischemia of the inferior wall of the left ventricle (maybe sinus node dysfucntion) ST elevations in leads V1-V4? proximal LAD, anteroseptal transmural ischemia ST elevations in V5 and V6 (maybe I and AvL): lCX transmural ischemia of the lateral wall of the left ventricle

Answer 52

A single sarcomere is the distance between 2 Z-lines, it is composed of overlapping filaments of actin and myosin as wel as structural and binding proteins (titin, alpha-actinin) The thin = actin filaments, in the I band are bound to the structural proteins at the Z-line; unbound ends project into the middle of the sarcomere, where they interact with thick / myosin filaments during muscle contraction A band always remains the same length during muscle contraction (A for Always) M line is where the MYOSIN filaments achor structure elements in the center of the sarcomere Myosin and actin filaments overlap at the segment of the sarcomere between the H and I bands I band = region of the sarcomere in which actin does not overlap with myosin, only actin H band = region where myosin does not overlap with actin, only myosin H&I band shorten during contraction

Answer 53

Patients with **Parkinson** dz have a **RESTING** tremor vs an **essential** tremor is classically worsen while maintiang a particular **posture** ( ie-holding an object = drinking from a glass, pouring tea....) ***_Essential tremor_*** = most commonly diagnosed movemetn disorder. often follows an **autosomal dominant** inheritance (positive family history), patients also report that their symptoms **subside with _alcohol_ consumption** Tx: **propranolol**, *_nonselective B-adrenergic antagonist_* thought to lessen the tremor via CNS systemic effects

Answer 54

Remember specificity --\> SPIN, you use it to rule IN a disease thus, to find the specificity, you want to find out: #true negatives / total # negatives (down the 2X2 chart = sensitivity or specificity; across the chart, PPV or NPV)

Answer 55

**PrP (prior protein)** in normal cellular protein is found in neurons that have alpha-helical secondary structure. In some patients, this protein undergoes confirmational change from **alpha-helical --\> b-pleated sheet isoform** = **highly resistant to proteases**, thus causing intracellular accumulation, this accumulation of abnormal protein is thought to cause prion disease HISTO: affected gray matter --\> **spongiform change/encephalopathy,** *_vacuoles form within the cytoplasm of neurons and neutrophils; no inflammatory changes*_. Later they grow bigger and _*form cys_*t, invoving larger areas of the brain tissue Examples: Creutzfeldt-Jakob disease, Bovine Spongiform ENcephalopathy (mad cow disease)

Answer 56

Sx: skin/mucosal itching, urticaria, angioedema, respiratory distress (laryngeal edema, stridor, hoarseness, bronchospasms, wheezing, chest tightness), GI (NVD), hypotension (dizziness, CV collapse) TX: intramuscular EPI, airway management and vol resuscitation Anaphylaxis type 1 hypersen, characterized by increased vascular permeability and multisystem edema, leading to massive shifting of IV fluid to the extravascular compartment. Symptoms often begin within seconds to mintes after intravascular exposure to an inciting factor but can take upt o 2 hours to develop with orally ingested antigens results in WIDESPREAD _MAST CELL_ AND BA_SOPHIL DEGRANULATION_ and results in **HISTAMINE** AND **TRYPTASE** release. [trypase is an enzyme that is relatively specific to mast cells and elevated serum levels of tryptase are often used to support a clinical dx of anaphylaxis after pt has been stablilized]

Answer 57

Present in all cells of the body but highest levels found in liver, bone and placenta

Answer 58

High affinity IgE receptor (FceRI) is found on mast cells and basophils and plays a primary role in mediating the allergic response -- The receptor normally **binds the Fc portion of circulating IgE** (via the sum of many weka non-convalent forces), coating the cell with various antigen specific IgE molecules -- when a multivalent antigen comes in contact with teh cell, multiple IgE antibodies become **CROSS-LINKED**, resulting in **AGGREGATION** of the FcRI receptors on teh mast cell surface --\> clumping of receptors leads to the **activation of non-receptor tyrosine kinase,** triggering intracellular cascade that ultimate results in mast cell and basphil degranulation

Answer 59

high-pitched blowing decrescendo diastolic murmur that beigns immediately after closure of the aortic valve and is best heard along the left sternal border at the third and fourth intercosta spaces while the patient is sitting up and leaning forward with the breath held in end expiratio

Answer 60

Insulin is an ANABOLIC hormone, that acts via receptor tyrosine kinase signaling to increase the synthesis of glycogen, proteins, fatty acids and nucleic acids. Insulin binds to the insulin receptor that has intrinsic tyrosine kinase activity @ cytoplasmic domain --\> receptor autophosphorylation --\> tyrosine phosphorylation of IRS (insulin receptor substrate) --\> 2 paths: **1. PI3K path:** glycogen, lipid and protein syntheis, also increases GLUT4 vesicle and translocation to the surface *Tyrosine kinase/phosphatidylinositol-3-kinase stimulaiton promotes glycogen synthesis by activating **protein phosphatase**, an enzyme that _dephosphorylates_ glycogen synthase --\> ACTIVATION --\> glycogen synthesis* **2. Activation of MAP** kinase pathway promotes mitogenic functions such as DNA synthesis and cell growth **_Insulin decreases blood glucose levels by:_** 1. inc glucose uptake into skeletal and adipose tissue 2. promoting the synthesis of glycogen, triglycerides, NA and protiens 3. inhibits glycogenolysis and gluconeogenesis

Answer 61

= type I What is the deficiency: Lipoprotein lipase, ApoC-2 (apoC2 deficiency activates LPL on chylomicrons and VLDL) What is elevated: chylomicros What are the major manifestations: acute pancreatitis, lipemia retinalis, eruptive zanthomas

Answer 62

Type II A What is the deficiency: LDL receptors, ApoB-100 What is elevated: LDL What are the major manifestations: Premature atherosclerosis, TENDON xanthomas, xanthelasmas

Answer 63

Type III What is the deficiency: ApoE What is elevated: chylomicrons and VLDL remnants What are the major manifestations: premature atherosclerosis, tuberuptive and plmar xanthomas

Answer 64

Type IV What is the deficiency: polygenic What is elevated: VLDL What are the major manifestations: associated with coronary disease, pancreatitis and diabetes

Answer 65

Creatinine and inulin- freely filtered, an insignificant amount of creatinine is secreted, not absorbed; urinary excretion = filtered load of substance regardless serum concentration PAH - filtered and activel secreted; even at low serum concentrations, urinary excretion exceeds the total amt filtered Urea- filtered and rebasorbed via passive diffusion into the peritubular capillaries; 20-50% of the filtered load is normally reabsored but urea has no Tm since it is passively reabsorbed Glucose- renal tubules reabsorb the entire filtered load of gluc as long as it is below the maximum tubular reabsorption ability (Tm) -- at higher plasma concentrations, glucose is excreted when the filtered amt exceeds the Tm of gluc (active reabsorption)

Answer 66

thionamide-induced agranulocytosis! Thionamides - MMI, PTU function by inhibiting **thyroid peroxidase** impaires iodine organification -- MMI is the preferred drug due to the risk of severe hepatotoxicity with PTU PTU useful for 1st trimester pregnancy, thyroid storm as it has additional effects of decreasing peripheral conversion of T4 to T3 MMI teratogenic Both PTU and MMI coudl cause agranulocytosis (absolute neutrophil count \<500) sx: fever, sore thora, oral ulcerations + other signs of infections **\*\*if this is suspected, the drug should be discontinued immediately and WBC count with differential should be obtained to confirm diagnosis**

Answer 67

neoplastic B-lymphocytes mature into plasma cells that synthesize abnormal typically large amounts of monoclona immunoglobulin or immunoglobulin fragments (light chains, etc) **\* M peak, anemia (normochormic & normocytic), lytic bone lesions (back pain, pathological fractures), renal insufficiency (related amyloid deposition and hypercalcemia)\*\*** SX: impaired hematopoiesis --\> **normochromic**, **noormocytic** **anemia** and weakness; **lytic bone lesions** classically affecting the vertebral column and causign back pain and pathologic features **hypercalcemia** and AL amyloidosis (contributes to renal dysfunction) Severe **amyloidosis** can also cause cardiac and cutaneous findings Lab findings: **Rouleau formation**, **bence-Jones** (immunoglob light chains) proteins in the urine serum protein electrophoresis is a more specific laboratory test used to determine if excessive monoclonal IG are present --\> an **M peak** indicates the presence of such immunoglobulins (usually IgG spike) [*_an M peak could also be seen in Waldenstrom macroglobulinemia and some other lymphomas]_*

Answer 68

= male-pattern hair growth in a women Most common cause is **polycystic ovary syndrome** features: **androgen excess**, ovarian dysfunction (anovulation), insulin resistance, obesity, many many subcapsular ovarian cyst --\> enlarged ovaries Treatment: wt loss, combined hormonal contraceptives, metformin OCPs work by suppressing LH secretion from the pituitary thereby decreasing ovarian androgen produciton; also increase sex-hormone binding globulin synthesis by the liver, decreasing free testosterone levels [pathogenesis: LH --\> theca cells --\> intra-ovarina androgen --\> follicular atresia; hyperandrogemia (hirtusim and other high andregen sx), in the periphery --\> E1 --\> endometrial hyperplasia/CA and DEC FSH --\> cystic deneration of follicles] virilization occurs w/very high androgen levels -- characterized by clitoromegaly, increased muscularity and voice deeping in addition to hirsutism

Answer 69

cevical dystonia of the SCM (localized uncontrolled muscle contractions causing pain or discomfort as well as physical deformity) local injection of botulinum toxin type B into the dystonic SCM muscle results in muscular relaxatio becasue teh toxin prevents presynapic release of ACh (nt responsible for muscle contraction from the nerve terminal at the NMJ) This effect is temperoary because of nerve terminal eventually regenerates in approx 3 months, thus therapeutic botulinum toxin injections must be repeated when the effects begin to diminish **c. botulinum gram + spore-forming anaerobic bacillus that synthesizes its potent neurotoxins intracellulary and release them by autolysis** *_\*\*can be used cosmetically to reduce the appearance of glabelar and other facial wrinkles, relax the lower esophageal sphincter in esophageal achlasia, treat muscle spams of MS and PD, and other conditions resulting from involuntary muscle contration\*\*_*

Answer 70

common cause of inflammatory gastroenteritis Fecal-orgal transmission- can be acquired from domestic animals (cattle, chicken, dogs!) or from contaminated food diarrhea is inflammatory and is accompanied by fever, abdominal pain and tenesmus (a continual or recurrent inclination to evacuate the bowels, caused by disorder of the rectum or other illness) associated with Guillain-Baree syndrome

Answer 71

Caused by: transient severe insult that leads to cell death --\> Shrinkage of the cell body, pyknosis of the nucleus (shrunken and basophilic), _loss_ of Nissl substance, eosinophilic cytoplasm Become visible **12-24 hours after the injury**, followed by death of the neuron -- remnants are phagocytoized by microglia, astrocytes proliferate on teh site of injury and form a glial scar reacting to _acute_ irreversible damage = red neuron \*normal aging is associated with progressive atrophy and neuronal loss BUT "red neurons" are NOT characteristic of normal aging

Answer 72

cause: loss of axon --\> enlargement of the cell body, eccentric nucleus, enlargement of the nucleolus, dispersion of the Nissl substance

Answer 73

causes: Progressive degenerative disease --\> Loss of neurons and functional groups of neurons, reactive gliosis

Answer 74

ipsilateral striate cortex, producing a contralateral homonymous hemianopia with macular sparing you get macular sparing because collateral blood is supplied by the MCA to the occipital pole, which porcesses central visual information \*\*an MCA stroke is characterized by contralateral motor and sensory deficits (upper \> lower limbs) and homonymous hemianopia WITH MACULAR INVOLVEMENT

Answer 75

--\> lateral medullary / Wallenbery syndrome CONTRALATERAL loss of pain and temp sensation IPSILATERAL deficits in: CN V, VIII, IX, X, XI

Answer 76

The _optimal site_ for obtaining vascular access in the lower extremity during cardiac catherterization is the *_common femoral artery BELOW the inguinal ligmanet._* Cannulation *_above the inguinal ligmanet_* can significantincrease the risk of **retroperitoneal hemorrhage**

Answer 77

adult= HgA: A2B2 fetal: A2G2 *_alpha always, gamma goes becomes beta_* each individual subunit of Hb are structurally analogous to myoglobin so if separated, the monomeric subunits will demonstate a hyperbolic oxygen-dissociation curve similar to that of myoglobin (no cooperativity!) Note: **P50 of Hb is 26 mmHg** P50 of mg is 1 mmHg --\> myoglobin has a much higher affinity for oxygen than hemoglobin Myoglobin is monomeric and the primary oxygen storing protien in skeletal and cardiac muslce tissue - only found in the bloodstream after muscle injury.

Answer 78

SX: low back pain (\<40 y/o onset insidious) morning stiffness that improves with exercise/use does NOT improve with rest, pain at night Hip adn buttock pain limited chest expansion and spinal mobiliyt enthesitis (inflammation at the site of insertion of a tendon to the bone) systemic symptoms (fever, chills, fatigue, wt loss) acute anterior uveitis (unilateral pain, photophobia, blurry vision) _Complications at extraskeletal systems-_ respiratory **(chest expansion should be monitored regularly in pt with AS)**, cardiovascular (ascending aortitis --\> dilation of the aortic ring and aortic insufficiency/regurg), eye (uveitis) RA seronegative! HLA-B27 + \*fusion of sacroiliac joints\* sacroiliac adn apophyseal joints of hte psine are the most commonly affected, leading to restricted spinal mobility many pt also develop peripheral arthritis adn enthesitis, which is defined as pain, tenderness and swelling at the sites of tendon insertion into the bone (ie- archiilies)

Answer 79

Heparin increases the effect of the naturally occuring anticoagulant antithrombin III (negatively charged chemical stored in mast cell granules) Binds to AT III via a pentasaccharide in the heparin chain --\> conformation change at AT III --\> inhibits Xa and neutralizes thrombin --\> anticoagulation Low molecular wt - better availablity, no need for lab monitoring, acts predominatly on factor Xa _not thrombin._ Used for: DVT, PE prophylaxis,

Answer 80

Methotrexate (MTX) is a folic acid analog that inhibits dihydrofolate reductase, enz that converts dietary folic acid to tetrahydrofolate; via direct competition MTX functions as a chemotherapeutic agent through the inhibition of DNA synthesis and as anti-psoriasis agent through immunodeficiency effects on activated Tcells BUT causes death of rapidly dividing cells, including those of the GI tract (pt could experience aphthous ulcers) and bone marrow (pancytopenia) **Folinic acid/Leucovorin** - can reverse MTX toxicity if given early [reduced form of folic acid that does not need DHFR to be converted to THF, thus it is not affected by MTX] BUT!! it also potentiates cytotoxicity action of 5-FU (binds thymidylate synthase) and is frequently included in colorectal CA regimens.

Answer 81

Sx: HYPOtension/shock, N/V, abdominal pain, weakness, fever Tx: hydrocortisone or dexamethasone high-flow IV fluids

Answer 82

Pernicious anemia could suggest an autoimmune disorder of parietal cells of the gastric body and funduns --\> chronic atrophic gastritis, wich is characterized by a histolgically loss of parietal cells with marked lymphocytic and plasma cell infiltration. Parietal cells are oxynitic (pale pink), found an dplate0like cells found predominately in the upper grandular layer that secrete gastric acid and iF IF is required for the absorption of cobalamin/vit B12 in the ileum, problem with parietal cells --\> vit b12/cobalamin deficiency progressive fatigue, lower-extremity parethesias, megaloblastic RBC = pernicious anemia

Answer 83

Dizygotic twins = fertilization of 2 oocytes by 2 different sperm = always 2 amnions and 2 chorions! Monzygotic twins arise from the fertilization of a single oocyte; twining may occur at different stages which affects the organization of the fetal membranes 0-4 days: Dichrionic/diamnionic 4-8 days: monochro/diamniotic 8- 12 days: monochro/monoam \>13 days = conjoined twins, monochro/monoamniotic

Answer 84

terminal bronchioles After thsi point, respiratory zone. Cilia terminate at respiratory bronchioles. Alveolar macrophages clear debris and partcipate in immne response

Answer 85

Secreted by atrial cardiomyocytes in response to atrial stretch, which is indicative of systemic volume expansion --\> lowers BP through peripheral vasodilation, natriuresis and diuresis ANP binds to the natriuretic peptide R on cell membranes, activating guanylate cyclase and forming cGMP Organs and tissues affected: kidney, adrenal gland blood vessels [overall vasodilation, increase sodium excretion/decrease reabsorpiton]

Answer 86

characteristic of chronic granulomatous disease - condition most often caused by an X-linked mutaiton affecting NADPH oxidase nl actiaved phagocytes to produce reactive oxygen species taht act directly as antimicrobial agents and activate granule proteases present in phagosomes Inactivating mutations of NADPH oxidase cause impaired intraceular killing by neutrophils and macrophages, leading ot recurrent bacterial and fungal infections...especially caused by CATALASE POSITIVE organisms (can destroy the hydrogen peroxide produced by their own metabolic activity)

Answer 87

S. Aureus contains coagulase activates prothrombin, resulting in conversion of fibrinogen to fibrin --\> fibrin-coating of the organism and resistance to phagocytosis

Answer 88

Lecthinase is also known as alpha toxin -- this is an enzyme with phospholipase C activity and the major virulence factor produced by C. perfringens Toxin increases platelelt aggregation and adherence molecule expression on leukocytes and endothelial cells, resulting in vasooclusion an dishcemic necrosis of affected tissues

Answer 89

The reid index is the ratio of the thickness of the mucous gland layer in the bronchial wall submucosa to the thickness of the bronchial wall btwn the respiratory epithelium and cartilage (not including the cartilage) It is snensitive measure of mucous gland enlargement - since progressive mucos gland enlargement is the major contributor to gradula bronchial wall thickening in chornic bronchitis, and since increasing wall thickness causes worsening airflow obstruction, *_elevaiton of the reid indez above the **normal value of 40%** correlate well with the duration and severity of chronic bronchitis_*

Answer 90

infection in children causes gingiovostomatitis = vesicular lesions on the lips and hard palate. HSV1 and other herpes virus are double stranded, enveloped DNA viruses \*Coxsackievirus causes hand, foot, mouth disease but spare the hardpalate and gums. (usually seen in the buccal mucosa, tongue and soft palate)

Answer 91

PCP = phencyclidine hallucinogen that causes dissociative symptoms, agitation, hallucinations and violent behavior **Ataxia**, **nystagmus** and **memory loss** are other distinguishing sx of PCP abuse

Answer 92

excessive insuline inadequate food intake physical activity/exercise [glut 4 translocated to the cell membrane in response to insulin and muscle contraction!] [*_infection, pain and sleep deprivation tend to cause HYPERglycemia rather than hypoglycemia-_* stressful situations increases catecholamine release, which rasies glucose by decreasing pancreatic insulin secretion and by increasing glycogenloysis and gluconeogenesis]

Answer 93

mental status changes, seizures, PROLONGED QRS duration, ventricular arrhythmias and anti-cholinergic findings cardiac symptoms are caused by blockage of cardiac fast sodium channels and inhibition of muscarinic acetylcholine, histamine and alpha-1 adrenergic R **_Sodium bicarnonate_** is used to treat associated cardiac toxicity and works by increasing serum pH (favoring the non-ionized/neutral form of the drug, thus less accessible to binding sodium channels) and increasing the extracellular concentration of sodium, which helps overcome the competitive inhibition.

Answer 94

Pyruvate --\> acetyl coA alpha-ketoglutarate --\> succinyl-coA

Answer 95

Releasing factor proteins bind to the ribosome when a ribosome encodes a stop codon (UGA, UAG, UAA) --\> stimulate release of the formed polypeptide chain and dissolution of the ribosome-mRNA complex

Answer 96

Cancer antigen 125 is aprotein produced by ovarian epithelia and is usually markedly elevated in cancerous ovarian cells compared to normal cells. It is neither sensitive nor specific for early EOC as it can be found in normal tissue and other cancers Risk factors for EOC: BRCA1/2 mutations, lynch syndrome repeated ovulation (nulliparity), ovarian dysfunction, endometriosis, postmeno age Protective factors: oral contraceptives, multiparity, breastfeeding, tubal ligation, salpingo-oophorectomy

Answer 97

Blurt aortic injury is most commonly caused by MCV underying mechanism is due to a sudden deceleration that results in extreme stretching and torsional forces affecting the heart and the aorta The most common area to be injured is teh aortic isthmus, which is tethered by the ligamentum arteriosum and is relatively fixed and inmonile compared to the adjacent descending aorta most pt die from aortic rupture before reaching hospital; otherwise have unspecific symptoms such as chest pain, backpain, SOB..widen mediastinum could be seen on x-ray isthmus \> ascending aorta \> descending aorta

Answer 98

First part emerges from the pylorus and is horizontal over the first lumbar - only part of the duodenum that is not retroperitoneal second part courses inferiorly at L1-L3; relatively close to the *_head of the pancreas_* and contains ampulla of Vater, site where pancreatic and common bile duct secretions are released Third part of the duodenum courses horizontally over L3, the abdominal aorta and inferior vena cava; it is in close association with the *_uncinate process of the pancreas*_ and the _*SMA_* Fourth part of the duodenum courses superiorly and to the left of L2 and l3 --\> becomes jejunum past the *_ligament of treitz_*

Answer 99

glucose increases serum glucose by increasing HEPATIC glucose production via GLYCOGENOLYSIS and GLUCONEOGENESIS. Glucogon-induced glycogenlysis is the predominant initial means of rapidly increasing blood glucose levels during hypoglycemia. Functions by stimulating G protein-couple dreceptors --\> increasing cAMP --\> activating protein kinase A --\> activation of glycogen phosphorylase = key glycogenolytic enzyme Activates rate limiting gluconeogenetic enzymes (pyruvate carboxylase, phosphoenolypyruvate carboxykinase) DEC intracellular fructose 2,6, bisphosphate (inhibiting glycolysis) \*\*during the first 12 hours of fasting, hepatic glycogenolysis is the source of most of the body's glucose Glucago has an insignificant effect on glucose homeostasis in skeletal muscle, adipose tissue and renal cortex

Answer 100

Reccurent lapses into sleep or naps (*_min 3X per week for 3 months)_* _At least 1 of the following_: *_Cataplexy_*- brief loss of musc tone precipitated by strong emotion (laughter, excitment..) **\*Low CSF levels of hypocretin-1** **\*Shortened REM sleep latency,** enter REM almost immediately Associated features: hypnagogic or hynopompic hallucinations, sleep paralysis Narcolepsy results from the depletion of **hypocretin-secreting neurons** in the **lateral hypothalamus** that *_involved in maintaining wakefulness_*

Answer 101

oral **metro** (mild to moderate cases) **Vancomycin** (severe cases) **Fidaxomicin** (macrocyclic antibiotic that inhibits teh signma subunit of RNA polymerase, leading to protein syntehsis impairment and cell death; oral, bacteriocidal activity, minimal systemic absorption, narrow spectrum; less effect on normal colonic flora than either metro or vanco - *_for patients with **recurrent** C diff or at an increased risk for recurrence._*

Answer 102

Increased sensistivity to everyday sounds One of the causes could be due to injury or lesion to the facial nerve. The stapedius nerve is a branch of the facial nerve, and innervates the stapedius muscle. This muscle serves to stabilize teh stapes. paralysis of the muscle, causes the stapes to oscillate mroe widely, producing hyperacusis ipsilateral hyperacusis is a common finding of Bell's palsy tx: re-training/sound therapy suing broadband noise/white noise

Answer 103

"bronze diabetes" skin hyperpigmentation, diabetes mellitus, pigment cirrhosis with hepatomegaly Hemochromatosis is an **AR** disease characterized by abnormally *_high iron GI absorption_* --\> iron overload, primarily in parenchymal organs such as the **_heart, pancreas and liver_** Lbas: mildly elevated LFT, elevated plasma iron with more than 50% saturation of transferrin and elevated serum ferritin

Answer 104

DIRECT agonist of dopamine --directly stimulate R Ergot compounds: **bromocriptine** nonergot: **pramipexole** and **ropinirole** **Others:** **selegiline** inhibits MOA-B, resulting in decrease central dopamine degradation **Amantadine** - enhances effects of endogenous dopamine **COMT inhibitors** (entacapone, tolcapone) and **dopa decarboxylase inhibitors** (carbidopa), decrease breakdown of levodopa in peripheral tissue,and increase amt of levodopa available to cross teh BBB

Answer 105

Multiple Myeloma Large eosinophilic casts composed of bence-Jones proteins are seen in the tubular lumen in myeloma cast nephropathy

Answer 106

pneumatosis intestinalis (air in the bowel - seen on abdominal x-ray as think curvilinear areas of lucency, parallel the lumen), abdominal distension, bloody stools one of themost frequent GI emergencies affecting newborns, RF: preterm infants due to GI an dimmunologic immaturity; thus upon enteral feeding, bacteria are introduced into the bowel wehre they proliferate excessively due to compromised immune clearance - impaired mucosal barrier allow the bacteria to invade the bowel wall, causing inflammation adn ischemic necrosis of the terminal ileum and colon --\> bowel becomes congested and grangrenous with formation of intramural gas collections 30% fatality surivivors are at risk for: strictures, bowel obstruction secondary to fibrosis

Answer 107

x-linked disorder \> pt of african, asian and mediterranean descent enz impt for pentose phosphate pathway impt in RBC for maintaining adequate concetrations of NADPH **Deficiency --\> low NADPH**, difficulty maintaining glutathione in teh reduced state --\> increase vulnerability of RBC to go into oxidative stress --\> hemolysis induced by **infection, drugs (bactrim, dapsone, anti-malarials, nitrofurantoin) and other oxidants (fava beans)**

Answer 108

Hereditary fructose intolerance (AR) Inability for fructose 1-phosphate --\> DHAP and glyceraldehyde (enters glycolytic pathway) sx: hypoglycemia and vomiting after frutose ingestion, failure to thrive, liver and renal failure tx: strict abstinence from dietary fructose ans sucrose (fructose + glucose) from diet This deficiency leads to the accumulation of the toxic metabolite fructose-1-phosphase. --\> deplets intraceullar phosphate, inhibits activation of hepatic phosphorylase and gluconeogenesis --\> lifethreatening hypoglycemia (sx: lethargy, sweating, vomiting, dehydration)

Answer 109

*_For liver function:_* **Impaired biosynthetic capacity?** Elevated PT hypoalbuminemia **Impaired transport and metabolic capacity?** elevated bilirubin *_For liver injury:_* **Markers of hepatocyte injury** Aaspartate aminotransfere, alanine aminotransferase AST \> ALT usually **Makers of cholestasis:** * elevated alk phosphase, elevated gamma-glutamyl transpeptidase (ggt not elevated in bone dysfxn)* other: thrombocytopenia (due to splenic sequestration of platelets) _**\*\* best markers for cirrhosis function: albumin, bilirubin, prothrombin time\*\***_

Answer 110

origin: S2-S4 Sensory: perineum Motor: urethral and anal sphincters important landmark for PN block: ischial spines [bony protrusions loc posterior lateral to vaginal side wall] sacrospinous ligament [firm band that runs medially and posteriorly from teh ischial spine to the sacrum] \*when administering a PN block, the ischial spines should be palpated intravaginally and the anesthetic should be injected medially in very close proximit to the ischial spine through the sacrospinous ligament \*internal pudendal artery and inferior gluteal artery, run medial to the PN; inadvertent injection can lead to hematoma and arrhythmia from intravascular infiltration of local anesthetics

Answer 111

L1-L2 sensory to scrotum/labia majora medial thigh (obturator does too)

Answer 112

results from failure of the primitive foregut to appropriately divide into separate trachea and esophageal structures Infants present shortly after birth with excessive secretions and choking/cyanosis during feeding dx: x-ray after the inability to pass a nasogastric tube into the stomach; could also show a stomach bubble, which results from air flow from the trachea through the fistula to the distal esophagus

Answer 113

above the 8th rib in the midclavicular line, 10th rib along the midaxillary line and 12th rib along the posterior scapular / paravertebral line Insertion of the needle lower than these points increases the risk of penetrating abdominal structures and insertion of hte needle on the inferior margin of the rib risks stricking subcostal neurovascular bundle (VAN)

Answer 114

MOA is a mitochondrial enzyme that: degrades *excess monoamine neurotransmitters* in presynaptic nerve terminals detoxifies dietary _tyramine_ in the GI tract **Tyramine hypertensive crisis** can occur in pt taking *_MAO inhibitors_* following consumption of foods containing high amounts of tyramine (aged cheeses, cured meats, draft beer) --\> hypertensive emergency (severe HTN, h/a, blurry vision) excessive sympathetic activity (tachycardia, diaphoresis, tremors) **\*tyramine is an indirect sympathomimetic** that is usualy metbaolized in the GI tract by MAO

Answer 115

Homcystinuria: most commonly affected enzyme = cystathionine synthase --\> affected pt can't form cystein from homocystein --\> cysteine becoming essential Homocystein builds up --\> hypermethioninemia Homocystinuria is a condition that leads to **hypercoagulability** and **thromboembolic occlusion**; pt with complete cystationine synthase deficiency can develop premature **acute coronary syndrome**, **ectopia lentis** (ocular lens displacement) and **intellectual disability** others also needed: *serine, cofactor B6, cystathionase*

Answer 116

osmium tetroxide, imparts a black color to fat

Answer 117

For example ferruginous bodies, (accumulation of iron in the lung by coating asbestos fibers --\> ferruginous bodies) stain brown on H&E dark blu eon Prussian blue stain

Answer 118

Glucose - normal protein - INCREASED cells - 90% LYMPOCHYTES

Answer 119

glucose - LOW Protein - HIGH cells - Neutrophilia

Answer 120

Liphophilic drugs (such as propofol) can be predicted using multi-compartment model of distribution administration of a single bolus: drug levels are high in the central comparments (plasma) then quickly distributed to well-vascularized peripheral compartments (brain, liver, kidney, lungs) due to increased lipohilicity of the tissues compared to the blood then over time, it is redistributed into poorly vascularized peripheral comparments (skeletal muscle, fat, bone) which has the highest volume of distribution for lipohilic agents \*\* redistribution occurs rapidly with highly lipohilic drugs and is responsible for the short duration of action seen with commonly used anesthetics such as propofol

Answer 121

Interact wtih major histocompatibility complex molcules on antigen presenting cells and the variable region of the T lymphocyte receptor to cause nonspecific, widespread activation of T cells. This results in release of IL2 from T cells and IL1 and tumor necrosis factor from macrophages. The immune cascade is responsible for the manifestations of toxic shock syndrome S. Aureus #1 culprit IL activation causes capillary leakage, circulatory collapse, hypotension, shock, fever, skin findings, multiorgan failure

Answer 122

Bicuspid aortic valve is the most common congenital cardiac malformation in pt with TS Usually isolated but could occur with other abnormalities such as aortic coarctation nonstenotic bicuspid aortic valve manifests wtih aortic ejection sound, which is an early systolic, high frequency click heard over the right second intersapce -- as it calcified, progressive valvular dysnfunction with aortic stenosis or regur will be produced. susceptible to infectious endocarditis

Answer 123

small to medium vessel vasculitis, characterized by late-onset of asthma, rhinosinusitis, eosinophilia (could invovle kidneys, GI, VC) **\*peripheral eosinophilia, antibodies against neutrophil myeloperoxidase pANCA** \*asymmetric multifocal **neuropathy**/ mononeuritis multiplex) common due to vasculitis affecting the epineural vessles - skin nodules - migratory/transiet pulmonary infiltrates - paranasal sinus abnormalities

Answer 124

Swan-Ganz or right heart catheters are used to diagnose PULMONARY HTN, occasionally for management of critically ill patients measures pulmonary artery occlusion pressure or pulmonary capillary wedge pressure, closely reflects **left atrial and left ventricular end-diastolic pressures** *during pulmonary artery catherization, ballow of the distal tip of teh catheter is inflated and the catheter is advanced forward through the right atrium, right ventricle and pulmonary artery and into a branch of the pulmonary artery..once lodged, the ballow is inflated obstructs blood flow, creating a continuous static column of blood bwt the cateter tip and left atrium*

Answer 125

caused by anti-GMB antibodies that react with a component of the alpha3-chain of **collagen type IV**. Patients typically present with rapidly progressive glomerulonephritis resulting in acute renal failure and hemoptysis due to pulmonary hemorage (anti-GBM antibodies cross react with other BM, especially those in the lung alvoli) LM: crescent formation with fibrin deposition FM: linear IgG and C3 deposition Nephritic = RBC casts, mild proteinuria type II hypersensitivity tx: emergent plasmapheresis

Answer 126

Wound contraction, a nl part of proliferative phase of would healing, involved contraction of actin in myofibroblast to approx wound edges. Transformation growth factor-beta (TGF-b) promotes differentiation of fibroblast into myofibroblast adn should diminish on completion of wound repair. In Keloids, TGF-b is produced excessively withouth regulation --\> scar extends beyond the borders of the original would, do not regress adn often recur after resection (collage 3) arise following minor or major trauma, can be raised, painful and pruritic familial tendency, particularly in persons of asian or african ethnicity

Answer 127

Acyclovir can cause **crystalline nephropathy** if adequate hydration is not also provided! Could be seen with acute elevations of serum creatininte --\> nephrotoxicity 5-10% of patients who receive drug via IV drug excreted primarily via glomerular filtration and tubular secretion, thus when concentration in collecting duct exceeds its solubility, crstallization, crstalluria dn renal tubular damage may result

Answer 128

AG bind to the 30s ribosomal subunit --\> causes cell to misread mRNA and as a result unable to perform protein synthesis Important forms of resistance: - methylation of the AG binding portion of the ribosome, inhibiting the ability of AG to interfere with protein translation - production of enzs that inactivate teh drug by altering its chemical structure - efflux pump that dec teh drug's intracell conc

Answer 129

Adjuvant therapy with monoclonal antibody against tyrosine kinase receptor =**Trastuzumab** **human epidermal growth factor receptor 2 (HER2)** trastuzumab binds a portion of the *_extracellular domain_* of HER2 and prevents activation of the transmembrane **tyrosine kinase** --\> this downregulates cellular proliferation and promotes apoptosis hER2 tyrosine kinase receptor is overexpressed in 20% of breast cancer patients

Answer 130

A preventable AE = injury to a patient (ie -delayed dx) due to failure to follow evidence-based best practice guidelines Non-preventable error is a complication that cannot be prevented given the current sate of medical knowledge (ie - allergic rxn) Sentinel event = unexpected occurrence involving death or serious physical or psychological injury (inpatien suicide, death of a full-term infant, retained object after surgery) that required immediate investigation

Answer 131

Statin: decrease cholestyramine: increase Statins are first line for most pt with hypercholesterolemia; competitively inhibit HMG CoA Reductase - enzyme responsible for the conversion of HMG CoA to mevalonate -- DECREASING hepatic cholesterol synthesis, instead upregulating LDL receptors causes an increase in LDL from the circulation (statin effect on TG and HDL are comparatively modest) Bile acid-binding resins (bile acid sequestrants such as cholestyramine) act by binding bile acids in the GI tract, interfering with the enterohepatic circulation of bile acids adn causing INC bile acid excretion --\> hepatic synthesis of NEW bile acids, thus consuming liver choelsterol stores, and hepatic uptake of LDL from the circulation for continued bile acid synthesis. hepatic choelsterol reduction is an actiating factor for HMG CoA reductase adn subseuently results in INC hepatic choelsterol synthesis This effect can be blocked with the addition of a statin drug to the treatment regime --\> greater reduction in LDL = synergistic action

Answer 132

With injury to the cardiac valves! Viradans is a gram positive organism taht is able to produce extracellular polysac = dextrans using surcose as a sbstrate -- dextrans faciliate strep adherence to FIBRIN Fibrin adn plateles are depsoited at sites of endothelial trauma, providing a site for bacterial adherence and colonization during bacteremia In pt with pre-existing valvular lesions, viridans can adhere to teh affeted valve and est infection --\> endocarditis \* the risk of endocarditis following dental procedusre is low with MVP, and antibiotic prophylaxis is not recommended although cases can still occur

Answer 133

Acute gouty arthritis, treat with **NSAIDS** (contraindicated in pt with renal failure or PUD) as first line, or **colchicine** as second line therapy, glucocorticoids For chornic gout - allopurinol (inhibits xanthine oxidase, which converts xanthine to uric acid) or probenecid (decreases proximal tubular uric acid reabsorption) \*contraindicated in acute gouty arthritis\*

Answer 134

The hallmakr of MS is demyelination of the axons, which can occur in any area of white matter Loss of myelin sheaths and depletion of oligodendrocytes is seen within the plaques Lipid laden macrophages containing the products of myelin breakdown are also seen within plaques Astrocyte proliferation response to CNS injury MRI brain scan is dx, typically showing demyelinating plaues CSF demonstarte INC conc of IgG -- oligoclonal band on protein electrophoresis conduction velocity slows in MS due to demyelination

Answer 135

ALL sx: fever, fatigue, pallor, petechiae, bleeding. Leukemia coudl spread causign lymphadenopathy, hepatosplenomegaly and bone pain T-ALL is more likely to present with anterior mediastinal mass that can compress teh great vessels --\> superior vena cava syndrome; respiratory symptoms, dysphagia. only about 15-17% of cases B-ALL manfiests with fever malaise bleeding bone pain hepatosplenomegaly but not really with mediastinal compression most common! Both will contain TdT (an antigen of lumphocyte precursor) pre-B cell surface markers: CD 10+, 19+, 20+ pre-T lymphoblast: CD2+, 3+, 4+,5+,7+,8+

Answer 136

STAGE not grade!! Extent of tumor expansion = stage vs degree of tumor differentiation = grade Stage A - confied to the mucosa, 90% survival + 5 yr if it involved the muscular layer = stage B 70-80% 5y C = lymph node involvement d= distatn mets, poor prognosis

Answer 137

Characterized by loss of speech and motor skills, deceleration of head growth, steretypic hand movements aft_er a period of normal development (5-18months) --\> loss of motor and language skills and development of stereotypic hand movements_ _**neurodevelopment** disorder that affects mainly **girls**_ _associated with mutations in the **MECP2** gene_

Answer 138

During ventricular systole, the myocardial blood vessels are compressed by the surroudining muscle --\> majority of LEFT ventricular blood flow occurs during DIASTOLE the systolic reduction in coronary blood flow is greates in teh SUBENDOCARDIAL region, making thsi portion of the left ventricle most prone to ischemia and infarciton.

Answer 139

The center of the airway pressure-volume curve is the functional residual capacity of the lungs. Identifies teh resting state where the airway pressure equals zero. at FRC, the intrapleural pressure is negative with a value of -5 cm H20 During inspiration, the intrapleural pressure decreases to ~ -7.5 cm H20, which hten induces a slightly negative alveolar pressure that drwas air into the lungs. (atmos pressure - 0) --\> pneumothorax causes the lung to collapse and the chest wall to expand out due to elasticity of the lungs, the alveolar transmural pressure is always positive, resulting in a perpetual collapsing force on teh lungs --

Answer 140

Tobacco use, esp smoking is the single most preventable cause of death and disease in the US - direct adverse effects - increases risk for macrovascular (MI, stroke) \*\*the risk of MI associated mortality begins to decrease immediately upon smoking cessation\*\* - inc risk for microvascular (DM) smoking cessation has a greater effect on reducing mortality than a daily aspirin, dietary and exercise modifications

Answer 141

Occurs as a sporadic mutation due to advanced paternal age in 85% of the cases as an inhereted AD in the 15% remaining homo dominant individuals usually are fatal, thus any affected individual is probably heterozygous thus 50% chance of passing on the gene results in a **GAIN OF FUNCTION** mutation in the **FGFR3** gene Achonrdoplasia is the most common form of short-limbed dwarfism and is caused by a mutation that results in constitutive activation of fibroblast growth factor receptor 3.

Answer 142

unenveloped, single stranded RNA virus spread through fecal-oral route \*\*high mortality rate in infected pregnant women\*\* INC incidence- young, middle-aged adults living in asia, sub-saharan africa and mexico with an average incubation period of six weeks. typically self limited, no chronic liver disease or carrier state

Answer 143

IgG Anti-Rh immune globulin consists of IgG anti-D antibodies that opsonize Rh+ fetal erythrocytes, promoting clearance by maternal reticuloendothelial acrophages and preventing maternal Rh sensitization. It is routinely administered to **Rh negative women** at **28 weeks gestation and immediately postpartum.** Rh antigens are a group of non-glycosulated, transmembrane proteins on the surface of RBC D antigen is the most immunogenic of the group present on RNC of Rh-positive individuals When an Rhnegative mother becomes pregnant with an Rh positive fetus, fetal RBC can enter the maternal circulation and elicit a maternal IgG antibody respone with formation of memory B-lymphocytes **(Rh allimmmunizaiton)** **After Rh alloimmunization occurs, subsequent pregnancies with Rh-positive fetuses will be at risk for hemolytic disease of the newborn** **To prevent maternal Rh allominnunization, Rh-negative motehrs must be prevents form mounting an immune response agaisnt D antige --\> anti-RhD immunge globulin is a polyclonal antibody consisting of IgG anti-D antibodies collected from pooled donor plasma --\> antiRhD antibodies bind to Rh-positive fetal RBC that enter the maternal circulation, preventing the interaction with the maternal immune system via sequestration and elimination by the mother's spleen** **_administration of anti-D IgG during preg does not cause significant transplacental fetal hemolysis because the quantity of anti-RhD administration is very small compared to that produced in a typical immunologic reation_**

Answer 144

AR disorder in which the lack of homogentisic acid dioxygenase blocks the metabolism of tyrosine leading to the accumulation of homogentisic acid clinical features include a **black urine** color when exposed to air; selectively binds to collage in connective tissues, tendonds and cartilage -- a blue-black pigment on the face and **ochronotic arthropathy**

Answer 145

zinc-finger motifs are composed of chains of AA bound together around a zinc atom via linkages with cystein and histidien residues they recognize specific DNA sequences and are used by many transcription factors to bind DNA and alter activity of target genes. **only INTRAacellular receptors that bind steroids, thyroid hormone and fat-soluble vitams act _diretly_ as transcription factors and contain zinc-finger binding domains (others can act indirectly, via signal transduction cascades involving second messangers)** zinc-finger is the most commonly identified DNA-binding domain in humans

Answer 146

associated with a number of neonatal complications including **transiet HYPOglycemia** in preg women with poorly controleld DM, fetus is subjected to high blood gluc levels since glucose can freely cross BUT maternal insulin does not cross --\>fetabl hyperglycemia leads to a compensastory rise in fetal insulin produciton and iselt cell hyperplasia fetal hyperinsulinemia --\> abnormal fetal growth resulting in macrosomia After birth, since the neonate is not longer exposed to high glucose levels of the mother but a hyperinsulinemic state persists for several days --\> hypoglycemia usually resolved in 3-7 days

Answer 147

Coronary venus sinus most drains directly into teh right atrium with the remainder raining into the other chambers of the heart Importance differences btw heart and other skeletal muscle and viscera blood flow: 1. myocardium is perfused during diastole (myocardial contraction during systole leads to compresison of the coronary arteirs and disruption of blood flow - contraction force is highest near the endocardium, resulting in severe coronary vessel compression in this area --\> subendocardium is most prone to ischemi) 2. myocardial oxygen extraction is very high 3. myocardia oxygen demand and coronary blood flow are tightly boupled - (adenosine and NO are the most important vasodilators responsibelf or increasing coronary flow)

Answer 148

psychotropic drugs - antipsychotics, antidepressants, benzos are the class most commonly associated with increased fall risk TCAamitrityline and long acting diazepam calcium channel blockers - amlodipine ibuprofen NSAIDs

Answer 149

MCL attaches proximally to the meidal epicondyle of hte femur and resists foces that push the knee medially MCL injury typically occurs after a twising injury or blwo to the lateral know while the foot is planted (v**algus stress inury)** **valgus stress test is positive indicating a MCL injury when tehre is laxity of hte know and/or medial joint line widening indicating MCL injry**

Answer 150

Receptors predominantely on bone and kidney tubules timulates teh formation of cAMP via Gprotein/Adenylyl cyclase pathwya on bone --\> resorption; PTH receptors located on osteoblast no clasts! ---\> causes osteoplast to increase RANK L and moncocyte CSF ---\> these two factors stimulate osteoclastic precursors to differentiate into bone-resorbing, mature osteoclasts DEC release of OPG -- "decoy" of recetor for RANK ligand. INC serum calcium (both resportion and from reabsorption oin the kindey) and decrease teh absorption of phosphorus from kidney tubules increases the activty of a-alpha hydroxylase increasing vitamin D in the kidneys Vitamin D does cause hypercalcemia but will not cause phosphaturia because PTH secretion diminished when there are high levels of calicum in the blood-- less active in discouraging phosphorous resprtption in the kindeys

Answer 151

IN cirrhotic pt, gynecomastia arised from hyperestrinims due to increased adrenal production of androstenedion with aromatization to estrone and eventual conversion to estradiol estradiol induces sex hormone binding globulin production (primarily in the liver but also in the uterus and testes), which results in increase T binding and decreased free T/E raio other manifestaiton of hyperestrinims in cirrhotic pt include spider angiomata, and in males testicular atrophy and dec body hair spider angiomata blanch on compression and size generally correlate with severity of liver disease

Answer 152

pyrrolidonyl arylamidase test S. pyogenes is positive \*\* glomerulonephritis is associated with prior strep pharyngeal or skin infection Acute rheumatic fever is associted with prior strep pharyngitis but NOT SKIN infection

Answer 153

The spleen (mesodermal with arterial suplly by a foregut vessel -itself is not a foregut derivative) iti s an intraperitoneal (not retro!) derived from mesoderm of the doral mesentary spleen is unique in that its bloody supply derives from a foregut derivative (splenic artery of the celiac trunk). venous retunr from teh spleen course through teh splenic vein to return to the portal circulation rather than the systemic circulation

Answer 154

compulsive consumption of nonfood and/or non-staple food source for **greater than 1 month** **most common in: pregnant women and school children** ingested substance is not a culturally accepted food source and the consumption is not appropriate to the person's development level often but now always associated with nutritional deficiencies, including iron and zinc deficiencies and anemial of any etiology three main types of subsances consumed: earth/soil rich substances, raw starch such as forn or corstach and ice

Answer 155

Neutrophil elastase it is released by neutrophils and macrophages major serum inhibitor ofe xtraceullar elastase is anti-1-antitrypsin (AAT) AAT deficiency could lead to panacinar emphysema and liver cirrhosis; panacinar emphysema results from teh unoppose action of neutotphil elastase on alvolar walls and **smoking** dramatically icnreases the risk of panacinar emphysema in pt with AAT def by ind**ucing inflammaiton (increasing neutrophil and macrophage activation)** and **permanently inactivnat AAT through oxidation of a crucial methionine residue**

Answer 156

dermatomyositis...systemic AI dx like polymyositis with additional inflammatory features involving the skin Muscle biopsy is dx and shows mononuclear **perimysial** infiltrates, **perifascicular atrophy** and **patchy necrosis** with **CD4+ T cells** **\*\*consider underlying malignancy / increased risk for occult malignancies -** colorectal, lung, ovarian, non-hodgkins lymphoma

Answer 157

D-xylose is absorbed at the proximal small bowel via passive diffusion and is used to differentiate pancreatic from intestinal malabsorption.

Answer 158

lactase deficiency results in incomple hydrolysis of the disac lactose into monosac gluc and galatose --\> osmotic diarrhea bacterial fermentation of lactose produces short-chain FA acids which lowers stool pH \<6, hydrogen gas which causes flatulence undigested lactose causes an elevation in stool osmotic gap (\>125) indicating the presence of unmeasured anions in the stool

Answer 159

gram negative **anaerobic** rods that can produce B-lactamase tx: **piperacillin-tazobactam** (combo of extended-spectrum penicillin with B-lactamase inhibitor) effective against most gram negative enteric rods (including pseudomonas aerugionsa) and bacteroides frailis *areas of necrosis and diminished blood suppply (such as chronic and nonhealing ulcers) faciliate the growth of anaerobes*

Answer 160

McArdle disease or glycogen storage disease V = glycogen phosphorylase deficiency causes failure of muscle glycogenolysis resulting in decreased exercise tolerance, muscle pain and cramping, myoglobinuria with physical activity

Answer 161

NNRTis are antiretrovirals that **do not req. activation** via intraceullar phosphorylation THe more common NNRTis include nevirapine and efavirenz best used in conjucntion with other antiretroviral agents for the tx of HIV AEs: abrupt-onset flu-like symptoms, abdominal pain, jaudice or fever may indicate potentially life-threatening **hepatic failure (most likely during the first 6 weeks of NNRTi therapy)** Life threatening skin reactions SJS, TEN have also been observed inhibit the syntehsis of viral DNA from teh RNA template

Answer 162

DEC **ADAMTS13** --\> l*_arge vWF multimers and resulting in diffuse microvascular platelet-rich thrombi_* or acquired/autoantibody or hereditary clinical prese: hemolytic **anemia** (**INC LDH, DEC haptoglbulin**) with **schistocytes** **Thrombocytopenia** (*_INC bleeding time, nl PT/PTT)_* sometimes - renal failure, neurologic manifestations, fever Mgmt: plasma exchange

Answer 163

Tranylcypromine phenelzine selegiline MAO is an enzyme located in presynaptic nerve terminals that is responsible for the breakdown of monoamine NTs MAO inhibitors work by irreversible binding and inhibiting MAO A and B --\> increased availability of monoamine NTs --\> increase their release into the synaptic cleft thus drugs that bind to MAO, since irreversibly bind, could take up to 2 weeks following discontinuation of the drug before the enzyme is resyntheseized to elvels adequate for normal monoamine degradation

Answer 164

conadministration of SSRI and MAO is contraindicated due to the risk of serotonin syndrome pontentially fatal condition characterized by restlessness, alt mental status, hyperreflexia and clonus, diaphoresis and tremors to avoid SS, pt must wait at least 2 weeks after MAO inhibitor discontinuation before initiating SSR therapy, allowing sufficient time fore regeneration of MAO

Answer 165

RA - swelling, pain, morning stiffness in multiple joints \> 6 months RA management = disease-modifying antirhematic drugs, which alleviate pain and inflammation and reduce long-term joint destruction adn disability includes: methotrexate (first line), sulfasalazine, hydroxychloroquine, minocycline, TNFalpha inhibitors take weeks short term tx = anti-inflamatory therapies, such as systemic and intraarticular glucocorticoids, or NSAIDs

Answer 166

CaRcinoD SSSyndrome **C**utaneous flushing **Ri**ght sided heart valvular disease (pathognomonic plaque-like deposits of fibrous tissue on teh right-sided endocardium, causing tricuspid regurg and right-sided heart failure) **D**iarrhea (secretory) Sob / wheezing Serotonin elevation (excessive serotoning, stimulates fibroblast growth and fibrogenesis --\> deposits of fibrous tissue occur most commonly on the endocardium, leading to tricuspid regur, pulmonic valvulopathy, right-sided heart failure -- generally only right side of the heart b/c pulmonary vascular endothelial monoamine oxidase inactivate vasoactive products) 5-HIAA (end product of serotonin metabolism), elevated in 24 hour urinary 5-HIAA levels diagnosing suspected carcinoid syndrome

Answer 167

cystic degeneration of the putamen as well as damage to other basal ganglia structures putamen is located medial to the insula and lateral to the globus pallidus on coronal sections

Answer 168

Clear cell CA is the most common subtype of RCC looks like a bunch of clear cells on imaging! classic (not really) triad: hematuria, flank pain and palpable abdominal mass w/ constitutional sx paraneoplastic syndromes due to the secretion of biologically active substance by the tumor cells may also occur - erythrocytosis and polycythemia can occur due to constitutive secretion of erythropoietin, hypercalcemia due to syn of parathyroid hormone-related peptide

Answer 169

metformin inhibits hepatic gluconeogenesis and increases peripheral glucose utilization it inhibits mitochondrial glycerophosphate dehydrogenase and complex I (first electron transport chain enzyme) --\> dec in cellular energy stores causes AMPK activation --\> dec hepatic gluconeogenesis INC peirpheral utilization of glucose **lactic acidosis** is a rare complication of metformin therapy but its *_risk is increased in pt with underlying renal insufficiency (measure creatinine!!)_*

Answer 170

Fungal cell wall is 1,3-beta-D-glucan (caspofunging and other echinocandin antifungals block glucan syntheiss) Fungal cell membrane: ergosterol Amphotericin B and azoles bind to ergosterol in the fungal cell wall inhibit ergosterol synthesis

Answer 171

*_1. initiation stage:_* (**decreased renal blood flow**) ischemic injury to renal tubules precipitated by hemorrhage, acute MI, sepsis, surgery *_2. Maintenance stage (24-36 hrs):_* decreased urine output (oliguria) fluid overload, increasing creatinine/BUN ratio, hyperkalemia *brown cast, low urinary osmo \<350, high urinary sodium \>30, high urinary fractional sodium excretion FeNa \>1* *_3. Receovery phase:_* gradual increase in urine output leadign to high volume diuresis. Electrolyte abnormalities may include DEC CONENTRATIONS OF of K, Mg, P04 adn Ca due to slow recovery of tubular fxn

Answer 172

typically presents with insidious onset of abdominal pain, diarrhea, and constitutional sx pt are **prone to developing fistuals/abscesses** as the lesions affect the entire thickness of the bowel wall perianal (skin tags, fissures) is also common Can involve the entire GI tract from mouth to anus, spares the rectum fecal occult blood testing is often positive, however gross blood is less commonly seen unless the colon is involved prone to developing fistulas and abscesses due to the **transmural inflammation** that occurs in CD. Fistulas are abnormal connection btw 2 epithelial-lined organs, usually form btw the bowe and nerby structures that include the skin, urinary bladder, vagina or bowe

Answer 173

Lymphangiosarcoma is a malignant neoplasm of the endothelial lining of lymphatic channels persisten lymphedema (with chronic dilaiton of lumphatic channels) predisposes pt to the development of this malignancy typical scenario - LS apperance approx 10 years post radical mastectomy for breast CA

Answer 174

CFTR transport of chloride into GI adn respiratory lumens, followed by sodium and water, leading to thin mucus dyfunction --\> dec water within the lum --\> thick dehydrated and viscous mucus within organs recurretn sinopulmonary infections congenital abscence of vas deferences pneumonia due to non-lactose fermenting, gram-negative rods (pseudo, burkholderia) very common Pancreatic insufficiency -- duct obstruction, distencious, subseuetn inflammation --\> fibrosis (PI usually present at birth in most pt) inability to absorb fats and fat sol vitamis -\> steatorrhea and failure to thrive, req. pacreatin enz supp