UWORLD questions brain scape

Question 1

Cryptococcus neoformans is a yeast that has what kind of capsule?

Answer 1

antiphagocytic polysaccharide capsule.

Question 2

what stain can identify the yeast form of C. neoformans

Answer 2

methanamine silver stain. Seen in tissues as round cells with narrow based buds

Question 3

how does the polysaccharide capsule appear on india ink vs mucicarmine

Answer 3

india ink: capsule appear as a clear,unstained zone. Mucicarmine stains red !!! Look at powerpoint.

Question 4

immigrant ASIA, intermittent abd cramps. Multiple respiratory infections over past 2 years, persistent cough? What will be seen in stool

Answer 4

rhabditiform larvae (strongyloidiasis) can molt directly into filariform larva –> autoinfection. only eggs and adult parasties are seen in intestinal biopsies. Symp: intermittent gastrointestinal or pulmonary symptoms. Pruritic, erythematous, linear streaks (larva currens) may occur on thighs and butt as larva migrate away from perianal region.

Question 5

the vagus nerve when stimulated release ACH –> bronchoconstriction. If shown a chart that shows a asthma drug working to reverse the irritant induced bronchoconstriction. Which drug is it?

Answer 5

ipratropium or tiotropium: they competitively BLOCK muscarinic receptors –> preventing bronchoconstriction.

Question 6

a pt with dermatomyositis, whats associated with it?

Answer 6

it may occur as a paraneoplastic syndrome, of an underlying malignancy, most commonly: ovarian (ovarian adenocarcinoma), lung, colorectal, and non-hodgkin lymphoma.

Question 7

21 yo co of repeated palpiations that start and stop abruptly. You suspect there is abnormal conduction pathway in this pts heart that bypasses the ATRIOVENTRICULAR NODE. What part of the ECG is most likely affected?

Answer 7

pt has wolf-parkinson-white traid image showing the ecg with arrow under PR interval (delta wave = shortened PR interval and widened QRS) the recurrent temporary tachyarrhythmias are due to an atrioventricular re-entry circuit, involing the AV node and the accessory pathway.

Question 8

a 22yo pt with hx of mitral valve prolapse comes to ER with intermittent fever and chills over past few days. Last week she had a dental cleaning. Physical exam reveals a nonejection mid systolic click followed by a late systolic murmur best heard at apex. blood culture show gram + bacteria that synthesize DEXTRANS from sucrose. WOTF would be the most likely adherence site for these bacteria?

Answer 8

virdians group strept. S.sanguinis - makes dextrans, which bind to fibirn-platelet aggregates on damaged heart valves. (most common mitral)

Question 9

if you give someone desmopressin (ADH analog) with central Diabete s insipitis their polyuria resolves. Vasopresin produces V2 receptor -mediated inc in water permeability w/in the corticol and medullary collecting duct. Renal clearance of what substances would decrease the most after this injection?

Answer 9

UREA. Bc vasopression (ADH) also activates urea transporters in the medullary collecting duct (imperable in the cortical CD), increasing the urea reabsorption and dec renal urea clearance.this passive reabsorption of urea into the medullary intersitium –> inc in medularry osmotic gradient allow production of maximally concentrated urine.

Question 10

viridans strept synthesize DEXTRANS from sucrose that facilitate strepts adherence to?

Answer 10

fibrin and platelets

Question 11

bacteria of lungtissue fails to decolorize w/ hydrochloric acid and alcohol after staining carbofuschin. WOTF cell wall components is responsble?

Answer 11

mycolic acid. (acid fast stain for mycobacteria) note the smear is first treated with aniline dye (carbofuchsin)

Question 12

tx of oral candidiasis

Answer 12

nystatin, or fluconazole, or caspofungin

Question 13

Calcium oxalate kidney stone. What med is most likely to precent recurrent stone formation in this patient

Answer 13

HYPERcalciuria is a risk factor for calcium stone. hydrocholorthiazide (thiazides) help by dec urine Ca excretion. They increase ca reabsorption through 2 mechanisms. 1. Inhibition of the Na/Cl cotransporter ( on the apical sided the DC tubule cells decreases intracellular NA concentrations. this activates the basolateral NA/Ca antiporter, which pumps NA into cells in exchange for Ca. resulting in dec intracellular Ca concentrations enhancing luminal Ca reabsorption across the apical membrane 2. hypovolemia induced by thiazides (inc Na and H20) reabsorption in proximal tubule, leading to passive inc in paracellular Ca reabsorption

Question 14

duodenal atresia (presents 1-2 days after birth, billious voting/distended abdomen and duodenum on X ray) what is the mechanism for development?

Answer 14

failure of gut recanalization.

Question 15

Delayed passage of meconium, abdominal distension and bilious emesis. Whats the disease and cause of it?

Answer 15

hirschsprung disease, caused by failure of neural crest cell migration in the gut causes AGANGLIONIC sigmoid colon/rectum.

Question 16

painless lower GI bleeding without emesis. Caused by the omphalomesenteric duct connects the midgut lumen w/ the yolk sac which failured to obliterate causing two things

Answer 16

vitelline fistula (complete failure) or a meckel diverticulum (partial failure).

Question 17

mid\gut malrotation caused by incomplete counterclockwise rot (180) can lead to cecum will be in RUQ and ladd (fibrous) bands connect the retroperitoneum in the RLQ to the right colon cecum by passing over the duodenum causing intestinal obstruction (bilious emesis during the first days of life). what embyonic process failed causing this?

Answer 17

midgut rotation around the superior mesenteric artery causing midgut volvulus.

Question 18

first line pharmacological tx for moderate to severe alcohol use disorder?

Answer 18

opiod antagonist NALTREXONE (Mu-opioid receptor blockade) its initiated while the patient is still drinking bc it blocks the rewarding and reinforcing effects of alcohol. This drug reduces craving!

Question 19

medications used to tx alcohol dependence?

Answer 19

natrexone, disulfiram (in pts that are abstinence bc it inhibits aldehyde dehydrogenase thus when alcohol is ingested it causes adverse effects).Acamprosate

Question 20

tetanus toxoid inactive vaccine - initiates what kind of immune response

Answer 20

humoral immunity: circulating antibodies that\ neutralize bacterial products

Question 21

a pt is experience unillateral vesicular rash single dermatome is present on chest. (herpes zoster) wotf is the pt most likely to suffer from within the next 6 months? A. recurrent skin rash, or B. persistent local pain?

Answer 21

persistent local pain (postherpetic neuralgia. “PHN”) often last for several months. Herpes zoster (occurs when latent VZV infection is reactivated within a single dorsal root sensory ganglion. Does not reoccur bc not herpes simplex virus.

Question 22

what are the two preferred diagnostic test for DM

Answer 22

HbA1C and fasting blood glucose level! Not oral glucose tolerance test (preferred in gestational and cystic fibrosis diabetes)

Question 23

why does epinephrine not increase renal BF like dopamine?

Answer 23

due to the lack of D1 receptor stimulation. Dopamine at low dose stimulates D1 receptors in renal vasculature and tubules inducing an inc in Renal blood flow, GFR, and NA excretion.

Question 24

what does dopamine do when given in high doses in reference to Blood flow

Answer 24

it stimulates B1 adrenergic receptors in heart, –> inc cardiac contractility, HR, and SBP. At higher end of the dose range, stimulation of a1 receptors in systemic vasculature –> vasoconstriction –> dec CO output do to inc afterload.

Question 25

elderly pt with diabetes and has malignant otitis externa (granulaiton tissue seen in the ear canal.

Answer 25

pseudomonas aeruginosa (nonlactose-fermenting, oxidase positive, motile gram negative rod) this is the most common cause of MOE in elderly diabetic patients

Question 26

where does the median nerve travel bw in the forearm.

Answer 26

bw the flexor digitorum superficialis and flexor digitorum profundus

Question 27

4 yo girl. Abd pain, blind pouch connected to ileum. Under microscopy, it demonstrates pancreatic acini in the mucosa. This finding best described as?

Answer 27

Ectopy. (microscopy and functionally normal cells/tissues found in an abnormal loction due to embryonic maldevelopment). Patient had meckles diverticulum.

Question 28

a pt with temporomandibular disorder. The motor and sensory components to this disorder. What nerve is responsible for the motor fibers to the tensor tympani causing the hearing probs?

Answer 28

mandibular nerve. Largest branch of the trigeminal nerve contains both motor and sensory components. The motor fibers innvervate the muscles of mastication, muscles of the floor of the mouth ( mylohyoid) tensor veli palatini, and the tensor tympani in the middle ear. thus if the pt is having both jaw pain and otologic symptoms its mandibular.

Question 29

the maxillary branch of trigeminal supplies?

Answer 29

mainly sensory fibers from the cheek, nares, upper lip and teeth., the pharyngeal palate and maxillary sinuses

Question 30

surge in anti-HBs and anti-HBc IgG, and possible anti-HBe represents?

Answer 30

had acute hep B and recovered successfully

Question 31

surge in only anti-HBs?

Answer 31

immunity to hep b due to vaccinations

Question 32

why can niacin cause gout?

Answer 32

it can dec renal excretion of uric acid –> inc blood levels and an inc risk for acute gouty arthritis.

Question 33

a pt with graves disease develops filtrative ophthalmopathy (due to glycosaminoglycans produced by the infiltrating Th1 cells cytokine release. What drug is used to tx this patients ocular symptoms

Answer 33

glucocorticoids (inflammatory infiltration.) don’t get tricked by reduced iodine organification (due to inhibition of thyroid peroxidase via methimazole, ,or ptu)

Question 34

what disorder should you avoid copper containing products due to associated risk w/ (liver failure, movement abnormalities, and psychiatric symptoms)

Answer 34

wilsons

Question 35

DNA repair disorders (ataxia-telangiectasia and xeroderma pigmentosum) should avoid

Answer 35

ionizing radiation.

Question 36

which histone is found outside the core of histones to help promote chromatin compaction?

Answer 36

H1

Question 37

what are the 4 mediators that attract/activate neutrophils?

Answer 37

Leukotriene B4!, C5A, IL8, bacterial products.

Question 38

methimazole moa?

Answer 38

inhibits thyroid peroxidase thus inhibiting iodine organification and coupling of iodotyrosines.

Question 39

propythiuracil moa?

Answer 39

inhibits thyroid peroxidase and 5-deiodinase preventing peripheral conversion of T4 to active T3

Question 40

embryology of kidney. Metanephric mesoderm/mesenchyme (blastema) develop into?

Answer 40

everything bw glomerulus – Distal convoluted tubue.

Question 41

what does the metanephric diverticulum (ureteric bud) form

Answer 41

ureter, pelvises, calyces, colleccting ducts!

Question 42

Cryptococcus neoformans budding yeast w/ thick capsules. Symptomatic infection w/ this organism most commonly manifest as?

Answer 42

meningoencephalitis. A lung infect does occur first, however its usually asymptomatic

Question 43

C. neoformans have round budding yeasts have peripheral clearings or halos, due to their thick __________

Answer 43

polysaccharide capsules

Question 44

what cuases comedonal and inflamatory nodular eruptions (ACNE)

Answer 44

methyltestosterone (androgens stimulate follicular epidermal hyperproliferation and excessive sebum production –> promoting acne. Anabolic steriod misuse is known to cause acne in atheletes. (note excessive perspiration doesn’t cause acne)

Question 45

during a midline episiotomy (vertical incision from posterior vagina opening, through the vag/subvaginal mucosa and to the____________?)

Answer 45

perineal body. Which is essential to the integrity of the pelvic floor.this is the tendinous center point of the perineum. (separates the urogenital and anal triangles)

Question 46

what would be cut if you did a mediolateral episiotomy?

Answer 46

transverse perineal muscle.

Question 47

immediately prior to delivery, estrogen stimulates upregulation of ? Leading to? It also increases expression of ______ receptors

Answer 47

gap junctions ( aggregated connexin! Proteins that allow passage of ions bw myometrial cells) bw individual myometrial smooth m cells. This inc in gap junction density at delivery heightens myometrial excitability. Also inc expression of uterotonic (oxytocin) receptors

Question 48

antibodies against desmoglein, a cadherin protein for desmosomes are found in?

Answer 48

pemphigus vulgaris

Question 49

antibodies to hemidesmosomes proteins causes

Answer 49

bullous pemphigoid and pemphigoid gestationis.

Question 50

hyaline, acellular deposted composed of plasma proteins in renal disease

Answer 50

diabetic nephropathy (kimmelstiel-wilson nodules)

Question 51

what stimulates the adrenal medulla (histology slide) to release hormones?

Answer 51

acetylcholine (released by PREganglionic sympathetic neurons) –>stimulating medullary chromaffin cells (modified POSTganglionic sympathetic neurons0 –> release epinephrine (80%) and nor epi (20%)

Question 52

Zona glomerulosa (rounded or arched clusters that secrete?

Answer 52

mineralocorticoid hormones (aldosterone)

Question 53

zona fasciculata (foamy appearing cells in columns secrete?

Answer 53

glucocorticoid (primarily cortisol)

Question 54

zona reticularis (basophilic cells in anastomosing cords) that secrete?

Answer 54

androgens.

Question 55

penicillins and cephalosporins funcdtion by irreversibly binding to penicillin binding proteins. Thus when subject to electrophoresis what would be bound to ceftriaxone?

Answer 55

tanspeptidases (are one form of PBP that function to cross link peptidoglycan binding proteins) thus cephalosporin “ceftriaxone” inhibit transpeptidase –> cell wall instability and bacteriolysis.

Question 56

digoxin

Answer 56

inhibition of Na K ATPase pump leading to increased parasympathetic tone leading to inhibition of atrioventricular AV nodal condunction

Question 57

pt on a antipsychotic block D2 receptors in the 4 dopaminergic pathways (mesolimbic system (for schizo) side effect though is that since it blocks D2 In the _________ pathway, thus disinhibiting the tonic inhibition of prolaction secretion.

Answer 57

tuberoinfundibular pathway. (not the neurons in the arcuate nucleus in the hypothalamus secrete dopamine (prolactin-inhibiting factor.

Question 58

blanching of a vein into which NE is being infused and induration and pallor of the surround tissue. Resulting in (alpha adrenergic) vasoconstriction which can leadto tissue necrosis. Tissue necrosis is best prevented by?

Answer 58

local injection of an alpha 1 blocking drug (pehntolamine.

Question 59

pt c.o. of ringing in ear (tinnitus), recurrent spinning episodes (vertigo), sometimes earfulness/pain, unilateral sensorineural hearing loss. Diagnosis and cause?

Answer 59

menieres diseae of the (inner ear) cause inc pressure and volume of endolymph in inner ear (endolymphatic hydrops

Question 60

brief episodes of dizziness spinning brought on by head movement , no auditory symp

Answer 60

BPPV, cause: otoliths in semicurcular canals

Question 61

single episodeof severe vertig,N/Vthat last days and no hearing loss. Diagnosis and cause

Answer 61

vestibular neuritis (labyrinths) cause inflammation of verstibular nerve (labyrinth) post viral or viral.

Question 62

a person with sarcodosis: wotf cells and cell products contribute to the pathology?

Answer 62

must know that granuloma formation is a manifestation of cell mediated immunity driven by Th1 type CD+ helper T cells, particularly IL-2 and interferon gamma which stimulates Th1 cell proliferatioin and macrophage activation

Question 63

Th2 tpe CD4 helper T cell predominatly drives what immune response. And promotes?

Answer 63

humoral immune responses: Th2 type CD4 helper T cells –> IL-4 which promotes IgE antibody product by B-cells , and IL5.which promotes the production and activation of eosinophil and B cell synthesis of IgA

Question 64

during peak exercise what do you expect your labs to be in terms of o2 co2, ph

Answer 64

inc Co2 product from skeletal muscles –> inc PCO2 mixed venous blood. no change in PaO2 or PaCO2, pH dec.

Question 65

secretin (released from S cells in duodenum) stimulates? To secrete

Answer 65

INCREASE pancreatic HCO3- and dec gastric acid secretion and inc bile secretion

Question 66

elderly women on Tea and Toast diet. Presents with easily bleeding gums brushing teeth, swollen gingiva that bleed on probing, image of perifollicular hemorrhages and coiled corkscrew hair). What hypoactive enzyme is causing this? And where

Answer 66

impaired collagen synthesis from vit C def (scurvy). Hydroxlation of proline and lysine in the RER.

Question 67

the greastest amount of H20 reabsorbed by the kidney occurs where?

Answer 67

highest in PCT (60%)and second highest in descending limb of henle loop.

Question 68

if fertilization and implantation occurs, when would B-hCG level first be detectable in serum?

Answer 68

8 days after fertilization.

Question 69

how many days after fertilization does the blastocyst implant ?

Answer 69

6 days

Question 70

pt that has coryneabacterium diptheriae the only tx is?

Answer 70

passive immunization (diptheria antitoxin) then penicillin or erythromycin, then DTP vaccine.

Question 71

DNA methylation to nucleotide residues (adenine and cytosine) by DNA methyltransferase) uses SAM as the methyl group donor is seen in which genetic process?

Answer 71

imprinting .

Question 72

a pt who receives the equivalent of more than 1 body blood volume (5-6 L) of whole blood or RBC transfusion over a period of 24 hrs may develop elevated ? That can cause what?

Answer 72

citrate –> hypocalcemia via chelating the calcium.

Question 73

HF symptoms.

Answer 73

exertional dyspnea and fatigue (caused by inability to inc CO) and orthopnea (due to elevated pulm circulation pressure and the resulting Pulm edema)

Question 74

on a left heart cath showing an excessive rise in left atrial systolic pressure, is a characteristic finding for?

Answer 74

mitral regurgitation.

Question 75

___ tends to elevate left Ventricular diastolic pressure, and dec aortic DP, due to?

Answer 75

aortic regurg. Regurgitant flow from aorta to left vent

Question 76

_____ causes an abnormal pressure gradient to form acorss aortic valve. Causing left vent Systolic pressure higher than aortic systolic pressure

Answer 76

aortic stenosis

Question 77

____ inc left atrial pressure during diastole (NOT systole) due to primary obstruction of left vent filling>

Answer 77

mitral stenosis.

Question 78

goat wool processing center, fever chest pain, hemoptysis, chest xray widened mediastinum. Large gram + rods that form medusa head colonies on media. This bacteria porduces an?

Answer 78

antiphagocytic capsule contain D-glutamate (not polysaccharide!!!)

Question 79

the most common site of nerve compression in a pt with common peroneal (fibular) nerve leading to weakness on dorsiflexion (foot drop) and everson, impaired sensation over the lat shin and dorsal foot. is most likely compressed where?

Answer 79

fibular neck (because it raps around here and then divides into the deep peroneal nerve and supericial nerve.

Question 80

which nerve gives off sensory branches to the dorsum of the foot and lateral shin?

Answer 80

superificial peroneal nerve

Question 81

what provides sensation only to the webspace bw the first and second toes?

Answer 81

deep peroneal nerve.

Question 82

homocystinuria occurs from genetic defect in cystathionine beta-synthase enzyme causing occurrence of muiltiple seemingly unrelated phenotypic manifestations in different organs as a result from a single genetic defect. This genetic defect is called?

Answer 82

pleiotropy.

Question 83

pt with niemann-picks disease. What substrate will be accumulated (note start at 5 months like tay sachs but said hepatosplenomegaly)

Answer 83

sphingomyelin

Question 84

the _______ contains ribosomal DNAcoding for ribosomal RNA (rRNA), components as well as new transcribed rRNA in associated with Ribosomal proteins that are translated in the cytoplasm from mRNA.

Answer 84

Nucleolus (be able to recognize on EM) the primary func: synthesis and assembly of immature 60s and 40s ribosomal subunits that are exported from nucleus to fully mature in the cytoplasm.

Question 85

1 wk old boy with parathyroid and thymic hypoplasia resulting in hypocalcemia and T cell deficiency. What is the cause of this?

Answer 85

maldevelopment of the 3rd (inf parathyroid and thymus) and 4th (sup parathyroid) pharyngeal/branchial pouches.

Question 86

hypopituitarism, hydrocephalus, diabetes insipidus, no hypocalcemia. Child. What embryologic structure is effect and what is the cause of symptoms

Answer 86

craniopharyngiomas arising from the remnants of the Rathke pouch. (invaginated oral ectoderm that eventually develops into anterior pituitary)

Question 87

failure of the anterior neuropore to close leads to neural tube defects such as?

Answer 87

anencephaly.

Question 88

insulin increases or decreases renal absorption of 1. sodium 2. glucose

Answer 88

1. inc Na reabsorption. 2. no effect on glucose.

Question 89

what is the most useful measure for assessing the degree of mitral stenosis.

Answer 89

S2 - to opening snap time interval.

Question 90

pts on carbamazepine for seizures since a child. Presents w/ dizziness and mild confusion over a week. Labs: low serum Na concentration its determined this condition is caused by a inc release of a hormone that is co-secreted with neophysins. if given a picture of the hypothalamus. Label where this hormone is secreted.

Answer 90

pt has SIADH due to carbamazepine, (or cyclophosphamide or SSRI). Secreted from posterior pituitary. ADH and oxytocin are synthesized w;in magnocellular neurons found in supraoptic and paraventricular nuceli in hypothalamus. They are packaged into vesicles with neurophysins (involved in posttranslational hormone processing adn stabilization during axonal gtransport)

Question 91

pt co solid food dysphagia sensation of food getting stuck in mid thorax. Barium esophagram: extrinsic compression on the mid esophagus.pt had Rheumatic heart disease a little while back. Enlargement of what structure is causing the dysphagia?

Answer 91

rheumatic heart disease –> mitral stenosis/ regurg (palpitations, exertional dyspnea). –> left atrial enlargement (posterior surface of heart) which lies directly over esophagus causing external compression of mid esophagus with dysphagia (cardiovascular dysphagia)

Question 92

a pt that is overdosing on warfarin (life threatening bleeds) What the FASTEST reversal of warfarins effects?

Answer 92

fresh forzen plasma (not vit K bc it takes time)

Question 93

filures of the rostral neuropore to close –> anencephaly, whereas impaired closure of the caudal neuropore casues?

Answer 93

Spina Bifida.

Question 94

if either neuropore does not fuse an opening persists bw the neural tube and amniotic cavity that allows leadage of ___________ and ________- into the amniotic fluid. Thus the detection of either of these used as prenatal screening of NTD.

Answer 94

(AChE) acetylcholinesterase and Alpha-fetoprotein (AFP) which can cross the placenta and is detectable in the maternal serum. ( so a pregnant women that undergoes an amniocentesis showing inc AChE are suggest failure of what? FUSION of the EDGES of the NEURAL PLATE.

Question 95

Which one would increased in obstructive lung disease A. TLC / RV ratio, B. RV / TLC ratio?

Answer 95

RV/TLC (bc RV = lung volume that remains after max expiration, the RV inc in COPD.) note its not TLC/RV, bc the TLC does inc in Obstructive lung disease, but it does so primarily through expansion of the RV compartment.

Question 96

a pt with MS has urge incontinence and urinary frequency in the setting of overactive or spastic bladder due to the presence of umn lesion in Spinal cord. What would you expect on urodynamic studies?

Answer 96

bladder is hypertonia. Bc there is little or no residual urine volume after emptying as bladder contractility is normal but distensibility Is poor. The bladder does not distend/relax due to loss of descending inhibitory control from the UMN

Question 97

why does the H. influ B vaccine contain both capsular polysaccharide of Hib and Conjugated tetanus toxoid.

Answer 97

Elicits T cell Dependent immune response (the conjugated carrier protein (tetanus toxoid[TTT] portien or out membrane protein [OMP] of N. meningitidiis) causes T cell mediated immune response) thus leading to long term immunity through productio of memory B lymphocytes

Question 98

what Benzo would you give to minimize daytime side effects (fatigue, impaired judgement)?

Answer 98

short (triazolam, oxazepam, midazolam or intermediate -acting (lorazepam, alprazolam, temazepam) given before bed.

Question 99

the most common congenital cardiac malformation in Turner syndrome?

Answer 99

Bicuspid aortic valve (nonstenotic bicuspid aortic valve manifests w/ an aortic ejection sound = (early systolic, high frequency click heard over the Right second interspace) note!!! It can cooccur with aortic coarctation.

Question 100

reperfusion injury (question said thrombus extracted followed by rapid surge of serum creatine kinase levels) this surge is best explained by?

Answer 100

Cell membrane damage. (enzyme leaks across damaged cell membranes into circulation)

Question 101

Intraventricular hemorrhage (IVH) is a common complication of prematurity. Occurs Most frequently before 32 weeks gestation and/or with birth weight < 1500 g. almost always occurs w/in first 5 postnatal days. Can present silent or altered consciousness, hypotonia, and decreased spontaneous movments. symptoms of catastrophic bleeding : bulding anterior fontanelles, hypotension, decerebrate posturing, seizures, irregular respirations, coma. blood found in the lateral ventricles. where do most IVH originate from?

Answer 101

germinal matrix - highly vascularized layer in the subventricular zone from which neurons and glial cells migrate out during brain development. The matrix contains numerous thin walled vessels lacking the glial fibers for support thus inc risk of hemorrhage.

Question 102

describe the amount of K+ in the tublar fluid as it flows along the nephron in comparison to the filtered potassium load (during high dietary K intake). Bowmans capsure____, proximal tubule____, Thick Ascending limb of henle _______, Collecting duct___

Answer 102

Bowmans capsule: fluid = 100%. Proximal tubule: TF 35%, (65% filtered), Thick ascend: TF 10% (25-30% filtered) collecting duct: TF 110%. (the principal and Alpha-intercalated cells of the late distal and cortical collecting tubules are the primary mediators of K regulation. during normal or increased K load stimulate principle cells to secrete K through apical K channels –> amount of K in CT to exceed filtered load. (not this question)Hypokalmeia –> stimulates reabsorption of K via apically located H/K-ATPases on A-intercalated cells.

Question 103

maternal ________ and __________ are the strongest risk factors for infant infection with HBV during delivery?

Answer 103

maternal viral load and HBeAg

Question 104

once an infant is infected with HBV they develop high levels of Viral load and HbeAg. Despite this high replication the infants enter an _____________ phase of chronic HBV infection which they are asymptomatic and have normal / mild elevated LFT.

Answer 104

Immune tolerant phase

Question 105

a pt with pulsatile vessels w/oin the IC spaces and diminshed femoral pulses relative to brachal pulses is assoicated with what condition?

Answer 105

turner syndrome (aortic coarctation, note they can have bicuspid aortic valve also)

Question 106

to inactivate thrombin heparin must bind to both antithrombin and thrombin together to form a ternary complex to inactivate thrombin. can unfractionated heparin or low molecular weight heparin do this?

Answer 106

only Unfractionated heparin has a pentasaccharide chain olong enough to do it. Vs LMWH that has greater activity against factor Xa than thrombin.

Question 107

main virulence factor in a pt with salmonellaosteomylitis. (gives you a 24 yo black pt with hx of pain crisis. They are now complaining of thigh pain. You must conclude its Sickle cell

Answer 107

capsule “vi anten that protects it from opsonization and phagocytosis.

Question 108

whats the main virulence factor of Staph aureus in osteomyelitis?

Answer 108

adhesion to collagen

Question 109

whats the main virulence factor in a pt with pseudomonas causing osteomyeliti? particulary in _____ pts

Answer 109

blue green pyocyanin pigment and this is common particulary in IV drug users

Question 110

what groin hernias occur BELOW the inguinal ligament

Answer 110

femoral hernias!!! Its also lateral to pubic tubercle and lacunar ligament (Immediately lateral would be femoral vein) ABOVE = direct and indirect

Question 111

what are femoral hernia prone to? Due to the femoral canal being small.

Answer 111

Incarceration which (cannot be reduced) this can cause bowel obstruction. This can lead to strangulation (few hours after incarceration due to impaired blood flow.

Question 112

granules containing cells containing eosinophils and the crystaloid bodies are most likely?

Answer 112

charcot-leyen crystals (contain eosinophil membrane proteins) can see in extrinsic allergic asthma

Question 113

if a parkinson pt is given IV dopamine and it does not work. What structure accounts for this?

Answer 113

tight junctions (the BBB is made from Tight junctions (zonulae occludentes) are composed of transmembrane proteins (claudins and occludins)

Question 114

PaCO2 is major stimulator of respiration in healthy individuals, however in patients with chronic COPD have dec sensitivity to PaCO2. these pts also have hypoxemia (pao2< 60) so arterial PaO2 levels become a significant contributor to the respiratory drive.. when supplemental oxygen is administered the rapid increase in PaO2 can reduce peripheral chemoreceptors stimulation dec in respiratory rate. thus this pts reduced spiratory rate is most likely caused by a sudden dec in stimulation of WOTF sensory receptors

Answer 114

peripheral chemoreceptors found in the carotid bodies and aortic bodies are the primary sites for sensing arterial Pao2 and are stimulated by hypoxemia.

Question 115

anterior compartment syndrome of lower leg with affect what structures?

Answer 115

deep peroneal nerve, anterior tibial artery, foot extensor muslces. Deep peroneal nerve injury (dec sensation to 1st-2nd toes, dec dorsifelxion of the foot, foot drop, and claw foot)

Question 116

pt that has sex with men, has symptoms of serum sickness like syndrome with joint pain, lymphadenopathy, and a pruritic Urticarial vasculitis rash, no jaundice and liver slightly enlarged. What infect does this pt have

Answer 116

acute hepatitis B , with symptoms including systemic skin and joint symptoms; hepatomegaly and elevated transaminases levels.

Question 117

enterococcal endocarditis (diastolic murmur at the left sternal border, nontender erythematous macules on hands and feet,fever no hx of heart disease): gamma -hemolytic (no hemolysis on agar), catalase-negative, pyrrolidonyl arylamidase +, lancefield group D gram + cocci that can greow in hypertonic (6.5%) saline and bile. (represents up to 30# of nosocomial endocarditis cases) what is the most likely procedure this patient had done w/in a month to get this.

Answer 117

the genitourinary tract (cystoscopy) is the most common portal of enry; gi (colonscopy) or obstetric procedures are also risk factors.

Question 118

(UPP) ubiquitin proteasome pathway is essential for breakdown of intracellular proteins, both native and foreign, helps recycle AA building blocks. Ubiquitin functions as a tag that is attached to proteins to mark them for destructions. This process is performed by what enzyme?

Answer 118

Ubiquitin ligases, which recognizes specific protein substrates and catalyze ubiquitin attachment. Tag protein –> proteasome (which breaks it down into their constituent oligopeptides –> AA

Question 119

so UPP role in immune response is related to its ability to degrade foreign intracellular proteins (viral). These proteins are degrades, and couple to?

Answer 119

major histocompatibility class I protein complexin the ER. They are then expressed on the cell surface for resentation of cytotoxic CD8+ lymphocytes.

Question 120

what organism. Oxidase +, gram -, comma shaped able to grow on high alkaline selective media (thiosulfate-citrate-bile salt-sucrose agar). This organism causes small outbreaks of water-borne gastroenteritis. What would be seen on stool microscopy in terms of leukocytes, etc.?

Answer 120

Vibrio cholerae - mucus and some sloughed epithelial cells. Since this is WATERY diarrhea, noninflammatory(enterotoxin) no fecal leukocytes or Red cells (erythrocytes)

Question 121

triad: cerebellar ataxia (gait is unsteady, spontaneously falls, eyes and head do not move smoothly) telangiectasias “spider angiomas (superficial blanching nests of distended capillaries sun exposed areas) inc risk of sinopulmonary infections. What is the cause of this disease

Answer 121

ataxia telangiectasia - caused by defect in a gene that codes for the ATM gene which is responsible for DNA break repair. The immune def primary manifests as an IgA def and predisposes to infections inn upper and lower airways.

Question 122

what lymph node drains the scrotum (pt with a scrotal abscess might have inflammed _____ nodes)

Answer 122

superficial inguinal lymph nodes

Question 123

what lymph nodes receive lymph drainage from the glans penis and supericial nodes

Answer 123

deep inguinal nodes

Question 124

if you have a left temporal hemiretina. Transmission of visual info to what structure disrupted?

Answer 124

left lateral geniculate body

Question 125

if you have 20 obervations record bw 10-12. if the next measurement is 26 what most likely to remain unchanged? Mean , mode, median, or standard deviation

Answer 125

mode- bc it’s the most frequently observed data point. Vs mean which is the average.

Question 126

they describe an HPV infection of the labia majora with warts. The virus also has affinity to infect what other structures?

Answer 126

true vocal cords not false, cervix, anal canal, vagina, HPV has a predilection for stratified squamous epithelium. In the repsiratory tract the true vocal cords are the only structure with squamous.

Question 127

the internal polypeptide assembly of HDV is (HDAg). Hep B assist what life cycle aspect of HEP D to cause infection?

Answer 127

coating of viral particles: HDAg is considered replication defective as it must be coated by the external coat hep B surface antigen (HBsAG) to penetrate the hepatocyte.

Question 128

18 you with intermittent burning sensation in his palms and soles that is exacerbated by stress and fatigue, he also has cluster of nonblanching red papulels in gluteal inguinal and umbilical areas. Labs: undectable a-galactosidase A. what is this pt at greatest risk of developing

Answer 128

renal failure. (pt has FABRYS disease)

Question 129

turners syndrome: most likely underlying mechanism for this condition?

Answer 129

Meiotic nondisjunction during gametogenesis (aneuploidy mc due to meiotic nondisjunction)

Question 130

a pt that is experiencing an acute hemolytic transfusion rxn. (fever and chills, chest and or back pain, and hemoglobinuria (red-to brown colored urine), hypotension, dyspnea). Whats the cause?

Answer 130

complement - mediated cell lysis (type II hypersensitivity)

Question 131

the most common organ injured during blut trauma ?

Answer 131

spleen.

Question 132

this organ is supplied mainly by an artery of the forgut even though the organ itself is not a foregut derivative. (look at a CT/mri of the abdomen and choose the correct organ.

Answer 132

spleen (derived from mesoderm) its not foregut. Like liver, gallbladder and pancreas.

Question 133

a pt with impaired nutrient absorption (malabsorption) the pt is presenting with either loose stools or steatorrhea. The most sensitive strategy for screening for malabsorptive disorders is?

Answer 133

stool microscopy with sudan III stain): identifies unabsorbed fat and confirm malabsorption. Fats are the Earliest and most severely affect nutrient in generalized malabsorption and test for fat malabsorption is most sensitive.

Question 134

the great saphenous vein is used for LAD revascularization. Know where its located!

Answer 134

courses superiorly from the medial foot, ant to the medial malleolus, and up the media laspect of the leg and thigh, in the proximal anterior thigh, 3-4 cm inferolateral to pubic tubercle, dives deep through the cribiform fascia of the saphenous opening to join femoral V. surgeons access it usually in medial leg, or less commonly in the *femoral triangle (inguinal lig superiorly, sartorius muscle lat, adductor longus m. medially.

Question 135

flue-like febrile illness w/ marked myalgias and joint pains (break bone fever) retro orbital pain, rash (white islands in sea of red)

Answer 135

classic dengue fever ( vs. dengue hemorrhagic fever: inc vascular perm, thrombocytopenia (<100,000), spontaneous bleeding –> shock), + tourniquet test

Question 136

a homeobox is a high conserved DNA sequence of about 180 nucleotides. A gene containing this sequence is called a homeobox or hox gene which codes for?

Answer 136

transcription factors

Question 137

which tissue cant utilize ketones for energy? Erythrocytes, heart muscle, renal cortex, skeletal muscle, brain?

Answer 137

erythrocytes (no mitochondria) ketone bodies are generated in liver, from FA and yields energy when converted to acetyl coa in mitochondria.

Question 138

the presense of hemosidern-laden macrophages in pulmonary alveoli indicate chronic elevation of pulmonary capillary hydrostatic pressure, most commonly as a result of?

Answer 138

left sided heart failure

Question 139

23 yo admitted for herpes encephalopothy (HA, fever, confusion) cerebrospinal fluid shows lymphocytic pleocytosis. The pt is treated with intravenous high dose acyclovir. He improves greatly. But 3rd day in hospital pt serum creatininne lv inc 3.4 from 0.9 how could this have been prevented?

Answer 139

aggressive intravenous hydration: intravenous acyclovir –> crystalline nephropathy crystals –> tubular damage. due to acyclovir exceeding its solubitility and now causes

Question 140

what would you expect to see interms of carboxyhemoglobin (%) [norm =0-2], PaO2 [norm= 85-100], and methemoglobin (%) [norm 0-1] if pt is suffering from CO poisoning

Answer 140

carboxyhemoglobin (40), PaO2 (95), methemoglobin (1). CO binds to hb with much higher aff than o2. hereby preventing oxygen binding to hemoglobin. It reduces oxygen unloading from hb, in the tissues. Co poisoning inc carboxyhemoglobin [] but does not affect the partial pressure of oxygen and does not precipitate methemoglobinemia.

Question 141

Bean-shaped gram negative coccci in pairs. Second most common cause of meningitis in pts < 60

Answer 141

Neisseria meningitidis

Question 142

blood oxygen saturation in fetus is highest where?

Answer 142

inferior vena cava

Question 143

45 yo, shows a CT of brain with mass in the parasagittal region and progressive neurologic symptoms, headache, whats the most likely cause

Answer 143

meningiomas (common, slow growing (Benign) intracranial tumor, arise in regions of dural reflexction (falx cerebri, tentorium cerebelli)

Question 144

is a meningioma is compressing the right .parietal lobe, located behind central sulcus, particuraly compressing the postcentral gyrus. What does this contain “sensory or motor”, You would expect the patient to have what symptoms?

Answer 144

it contains the somatosensory cortex - thus a medial location of a tumor would result in contralateral sensory loss in the lower limb. Also if it involved the parietal association cortex on the right (nondominant hemisphere) you would see contralateral. hemineglect. due to this regions role in visuospatial processing

Question 145

fever, back or flank pain, inguinal mass, and difficulty walking. Pt prefers to keep his leg flexed and exsternal rotation. What muscle is affected?

Answer 145

psoas abscess (major function flexion of hip) pain exacerbated when muscle stretched or extended. (extension of the hip = psoas sign)

Question 146

condensed body composed of heavily methylated DNA at the periphery of the nucleus. This region of DNA is most likely associated with what genetic finding?

Answer 146

low transcription activity (example compact herterchromatin (Barr body)) herterochromatin is condensed chromatin composed of heavily methylated DNA in Tight associated with Deacetylated histone. Thus it has low levdel of transcriptional activity. contrast - euchromatin (loosly arranged and exhibits a high level of transcriptional activity

Question 147

systemic arterial pressure normally falls by < 10mmhg during normal inspiration. What is it called when it drops (> 10 mmHg)

Answer 147

pulsus paradoxus: its detected by inflatting a BP cuff above systolic pressure and gradually deflating it. The diff bw the systolic pressure at which korotkoff sounds first become audible during expiration and the pressure at which they are heard throughout all phases of respiration quantifies pulsus paradoxus

Question 148

bp cuff is inflated to 140 and pressure release. At 120 intermittent korotkoff sounds are heard only during expiration. At 100 mmhg, korotkoff sounds are heard throughout the respiratory cycle. This PE finding can be seen in which of the following conditions>

Answer 148

pericardial disease

Question 149

pathology of how pericardial disease (acute cardiac tamponade) can impair expansion.

Answer 149

the inc right Vent volume occuring with inspiration —> bowing of the interventricular septum toward the left vent. This leads to a dec in LV EDV and SV. With a resultant dec in systolic pressure during inspiration

Question 150

increased activity of a specific intracellular enzymes are more susceptible to developing benzopyrene-induced lung cancer. What over active enzyme is the cause?

Answer 150

microsomal monooxygenase (cytochrome p450 monooxygenase) most chemical carcinogens enter body in inactive state (pro-carcinogens). They are converted to active metabolites by CYP 450 oxidase system

Question 151

both multiple motor & > or = vocal tics (grunts, snorts, throat clearing, sniffling, coprolalia) (not necessarily concurrent, > 1 year) onset before age 18 diagnosis and tx?

Answer 151

tourette disorder and TX: antipsychotic, alpha-2 adrenergic receptor agonists, behavioral therapy.

Question 152

if shown a picture of langerhan giant cells (multiple nuclei peripherally organised in shape of horseshoe) in a pt with TB. What is the most like cause of this finding?

Answer 152

stimulation by CD4+ Th1 lymphocytes (the macrophages that form these giant cells are activated by CD4+ TH1 lymphocytes) langhan giant cells are characteristic of granulomatous conditions.

Question 153

topical prostaglandins (latanoprost) help tx glaucoma how?

Answer 153

inc outflow of aqueous vis the uveoscleral pathway and are preferred tx for open-angle glaucoma.

Question 154

histo shows diffuse infiltrate of lymphoid cells w/ numerous mitotic figures, and interspersed macrophages surround by clear spaces. This is describing?

Answer 154

burkitts lymphoma: benign macrophages that pahgocytize the resulting cellular debris (“tingible body macropahges”) are diffusely distributed throughout the malignant tissue. The clear spaces that surround these macropahges contribute to the starry sky appearance.

Question 155

in burkitts lymphoma the gene translocated in these lymphoid cells produces a protein that is most directly responsible for?

Answer 155

transcription activation. C-Myc oncogene on long arm chromosome 8 and Ig heavy chaing region on chromo14 [t(8:14)] the product of c-Myc is a nuclear phosphoprotein that functions as a transcription activator controlling cell proliferation, differentiation and apoptosis.

Question 156

in follicular lymphoma T 14:18. this leads to overexpression of the BCL-2 that functions to

Answer 156

apoptosis inhibitor protein

Question 157

G protein coupled receptors that bind glycoprotein hormones (TSH,LH, FSH) contain 3 major domains: extraceullar domain (ligand binding), a transmembrane doamin, and intracellular domaincoupled w/ heterotrimeric G proteins. The transmembrane domain is made up of nonpolar, hydrophobic amino acids (alanine, valine, isoleucine, phenylalanine, tryptophan, methionine, proline, glycine). they are arranged in an alpha helical fashiion (7-alpha helices) and project their hydrophobic R groups outwardly which functions to?

Answer 157

anchoring the transmembrane region of the protein to the hydrophobic core of the phospholipid bilayer. Answer choice (anchoring to the cell membrane)

Question 158

cancer cells may develop the ability to alter the FAS proteins and fas receptors by converting it to a soluble form that is not expressed on the cell surface, which allows it to evade apoptosis. How might the cancer cells do this?

Answer 158

alternative splicing: process by which a single gene can code for various unique proteins by selectively including or excluding diff DNA coding regions (Exons) into mature mRNA

Question 159

a pt taking etoposide for testituclar cancer. The teoposide killed cancer cells show a high number of double stranded DNA fractures. These fractures are due to dysfunction of?

Answer 159

topoisomerase II: etoposide is a hemo agent that inhibits the sealing activity of topoisomerase II. Tx w/ etoposide causes chromosomal breaks to accumulate in dividing cells –>. Cell death.

Question 160

irinotecan/topotecan inhibit eukaryotic ______? Leading to accumulation of Single stranded DNA breaks.

Answer 160

topoisomerase I

Question 161

what bacteria is associated with toxins that bind specific receptors on intestinal mucosal cells and are internalized allowing both toxins to inactivate Rho-regulatory proteins involved in signal transduction and actin CYTOSKELETAL STRUCTURE** maintenance. as a result the toxin cuases diruption of intracellular TIGHT junctions –> cell rounding/ retractio0n and increased (paracellular) intestinal fluid secretion.

Answer 161

C difficlile: Toxin A (enterotoxin) and Toxin B (cytotoxin)

Question 162

what are the most important opsonins (coating proteins)?

Answer 162

IgG (immunoglobulin) and complement C3b

Question 163

neuropathologic findings in pts with friedeich ataxia are due to?

Answer 163

spinocerebellar and lateral corticospinal tract degeneration (gait ataxia and spastic muscle weakness), other characteristics of the disease 2. degeneration of dorsal colums and dorsal root ganglia (loss of position and vibration sensation). 3. kyphoscoliosis and foot abnormalities (pes cavus), 4. hypertrophic cardiomyopathy annd CHF, 5. diabetes mellitus develops in 10% of pts.

Question 164

pt recently returned from Mexico, presents w/ low grade fever, anorexia/nausea, dark colored urine, and right upper quad abd tenderness for two days is highly suggestive of? What findings are most likely to be seen in liver biopsy?

Answer 164

acute HAV, acute hepatitis due to most hepatropic viruses causes hepatocyte swelling: hepatocyte ballooning degeration and apoptosis w/ mononuclear cell infiltration. (hepatocyte necrosis is characterized by cellular swelling and cytoplasmic emptying (ballooning degneration) likely caused by ATP depletion and diruption of intermediate filament network.)

Question 165

why might blood glucose be normal and not fall into hypoglycemic range w/ fasting. Which hormone contributes to this pts labs by binding to an intracellular receptor?

Answer 165

by counterregulatory hormones specifically in this patient cortisol: unlike the other counterregulatory hormone receptors, cortisol receptors are located w/in cytoplasm and translocate to the nucleus after binding to their substrate. In the nucleus. The cortisol receptor complex binds to hormone responsive DNA elements, altering gene transcription to enhance hepatic glucose production and limit peripheral glucose utilization.

Question 166

pt with crampy abdominal pain and vomiting. Previous hx of acute calculous cholecystitis. PE: distended typanic abdomen w/ high pitched bowel sounds. Abd xray: air in gallbladder and biliary tree. Diagnosis and this pts gallstone is most likely lodged in what site?

Answer 166

Gallstone ileus common complication of longstanding choleithiasis. Usually occur elderly women. A large (>2.5cm) gallstone causes formation of cholecystoenteric fistula bw gallbladder and adjoining gut (most often duodenum) due to pressure necrosis and erosion. fistula allows gall stone into small bowel where it becomes trapped in ileum. –> small bowel obstruction.

Question 167

pt in bat cave 4 wks later develops painful spasms, progressive paralysis, coma, dies. What intervention would most likely prevented the development of this illness?

Answer 167

*inactivated vaccine = prophylactic vaccination, post exposure: vaccine and rabies immune globulin immediately after exposure to high risk wild animal.

Question 168

whats the long term effects of estrogen tx on thyroid hormones

Answer 168

increased total T4 pool NOT (dec free T4 levels).circulating thyroid hormone consist of 2 fractions, a protein bound fraction (not active) and free fraction that’s able to enter target cells via carrier mediated mech. more than 99% of circuating thyroid hormone is boundn to plasma protein creating a large circlating reservoir pool of thyroid hormone. Inc estrogen activity –> inc circulating TBG levels which causes reduction in Free T4 and T3. this causes a transient inc in thyroid hormone production until the additional TBG becomes saturated w/ thyroid hormone, and free t4 and t3 are restored. thus inc TBG –> inc in total t4 (bound T4 + free T4) as well as total T3. however the level of free thyroid hormone remaind normal.

Question 169

hallucinations of recently deceased relatives in children are part of a normal grief rxn and may not be indicative of major psychiatric illness. True or false?

Answer 169

true.

Question 170

what is kinesin protein function?

Answer 170

microtubule associated motor protein: function is ANTEROGRADE transport of intracellular vesicles and organelles toward the plus (rapidly growing) ends of microtubuels

Question 171

toxic insult to protein kinesin. Which of the following is likely to be absent from tissues on histological examination as a result?

Answer 171

secretory vesicles in nerve terminals.

Question 172

a pt with multiple myeloma. You expect to see what lab values for urinary ca, pth, PTH related protein, 1,250 dihydryoxyvitamin D.

Answer 172

pth dec, urinary ca inc, 1,25 vit D = dec, PTH related protein normal. (hypercalcemia due to osteolysis induced by tumor cells. Inc serum Ca inhibits PTH production, low levels of PTH caused inc Urinary loss of CA (hypercalciuria). Hypercalcemia and light chain cast nephropathy –> progressive renal failure –> low 1,25 vit d

Question 173

what part of the TCA cycle is dependent on thiamine

Answer 173

a - ketoglutarate –> succinyl coa. Need it for A ketoglutarate dehydrogenase complex.

Question 174

in pt with delta F508 mutation cystic fibrosis transmembrane conductance regulator (CFTR). Wotf electrolyte disturbances is most likely due to the 1month symptoms of (lethargy, vomiting) and dehydration from vomiting?

Answer 174

hyponatremia bc the CFTR protein is regulating the CL channel that allows NA, CL, water flow across the pithelial membranes of the airways, biliary tree, ,intestine, and sweat ducts, and pancreatic duct. Postiive sweat test with have high CL and NA in it. tx is salt supplementation

Question 175

immigrant withhx of cardiac rhythm abnormalities and presents with well demarcated erythematous rash on face and trunk. Pt denies hair loss, mucosal ulceration, or photosensitivity.. Has a + ANA. The pt should be specifically question about the intake of what med?

Answer 175

procainamide = drug induced lupus (Hydralazine, procainamide, isoniazid, minocycline, quinidine)

Question 176

autosomal recessive polycystic kidney disease (bilaterally enlarged kidneys will diffuse small cyst in fetal kidneys and oligohydramnios). What is most likely to be present in newbord after birth?

Answer 176

respiratory distress

Question 177

what will you see on liver biospy in child with reye syndrome?

Answer 177

microvesicular steatosis

Question 178

30 yo ASIAN male w/ extertional calf pain and painful foot ulcers demonstrates Hypersensitivity to intradermally injected tobaco extract. What pathologic processes is most likely responsible for this pts condition?

Answer 178

segmental vasculitis extending into contiguous veins and nerves. Pt has thromboangiitis obliterans (buergers disease),usually seen in smokers, w/ onset before age 35, associated w/ hypersensititivity interdermal injections of tobacco extracts. This segmental thrombosing vasculitis often extends into contiguous veins and nerves, encasing them in fibrous tissue

Question 179

clostridium perfringens, can cause gas gangrene, what else is it commonly associated with?

Answer 179

transient watery diarrhea and abd discomfort.

Question 180

a pt with parkinsons. Genetic analysis shows Loss of function mutation in a gene that leads to an accumulation of misfolded proteins. What biochemic process is most likely defective in this pt?

Answer 180

ubiquitination: ubiquitin is a protein that undergoes ATP-dependent attachment to other proteins, labeling them for degradation. These modified proteins enter the proteasome and are degraded into small peptides. Impairtment of the ubiquitin-proteasome system –> development of neurodegenerative disorders. (parkinsons, and alzheimers)

Question 181

what is the underlying mechanism for a zenker diverticulum formation?

Answer 181

cricopharyngeal motor dysfunction: abnormal spasm or diminshed relaxation of the cricopharyngeal muscles during swallowing.

Question 182

old man with HF. Displaced apical impulse at 6th ic space, S3 high volume, collapsing carotid pulses. Bilat pedal edema, mild heptomegaly. Dec light touch and vibration In feet, w/ dec knee and ankle reflexes bilat. Generalized weakness, fatigue, tingling both lower limbs. what nutrient def?

Answer 182

thiamine : wet beri beri : high output congestive heart failure + dry beri beri symptoms of symmetrical peripheral neuropathy)

Question 183

26 yo found dead. Long hx of alcohol and drug abuse and did rehabilitation 6 months ago. Pt had a hx of depression and anxiety that was being treated. According to epidemiological data, overdose of WOTF drug grps is most likely related to her death? (A. alcohol, B. Benzos, C. Opioids)

Answer 183

opioids. In the US the majority of overdose deaths ar ecaused by opioids (analgesics and heroin)

Question 184

pt with reperfusion injury due to ROS. Which enzyme / enzymes will are most likely to neutralize these toxic molecules?

Answer 184

glutathione peroxidase, SUPEROXIDE dismutase, catalase. (all convert ROS- –> h2o and oxygen.

Question 185

polygenic inheritance means it depends not only on genetics. Example?

Answer 185

androgenetic alopecia (male pattern baldness) = mc type of hair loss in male and females. Driven by both hormonal and genetic factors.

Question 186

cancer above the pectinate line in rectum what lymph nodes should you check

Answer 186

internal iliac

Question 187

multinucleated giant cells can indicate what infection that has vesicles

Answer 187

herpes infectiono such as shingles.

Question 188

what is effect modification? (its most common confused with confounding bias)

Answer 188

effect mod: is present when the effect of the main exposure on the outcome is modified by the presence of another variable. It will show significant difference bw the strata, vs confounding bias usually does.

Question 189

19 yo brought to ER for MVA accident, hx of celiac disease and 3 episodes of pneumonia. BP 80/45, pulse 130, US: splenic laceration. She is transfused with O negative packed RBCs. During transfusion the pt develops facial swelling, generalized hives and SOB. Diagnosis?

Answer 189

Selective IgA def: presents: usually asymp, recurrent sinopulmonary ,GI infections, autoimmune, ANAPHYLAXIS during transfusions. Diagnosis: low or absent serum IgA levels, normal IgG and IgM

Question 190

def in ornithine transport from cytosol into mitocondria. 4 yo presents with poor feeding and vomiting, exacggerated deep tendon reflexes. What nutritional restriction can help improve this pts condition

Answer 190

limit proteins. Def in ornithine translocase def, which results in defect in hepatic urea cycle. Which converts ammonia generated from AA catabolsium into urea, urea cycle defects ause ammonia to accumulate in blood –> progressive lethargy, vomiting, seizures, cerebral edema (hyperreflexia, chorea, abnormal posturing if severe)

Question 191

collagens triple helical conformation occurs due to the simple and reptitive AA squence w/in each alpha chain. Which AA is most likely to be found in highest quantitiy in these fibrillar proteins (fibrils separated)? A. proline B. glycine, C. lysine

Answer 191

glycine: occupies every third amino acid position (Gly-X-Y)

Question 192

quartback take blow to arm when throwing, flattening of the deltoid. Loss of sensory to deltoid What is the injury

Answer 192

anterior dislocation. Classically follow blow to an ext Rot and abd arm (throwing a football). When head of huemrus is displaced ant, there is flattening of deltoid prominence, protrusion of acromion, and ant axillary fullness.

Question 193

what nerve is must commonly injured during anterior dislocation of humerus. What does it innervate

Answer 193

axillary n. sensory innervation to deltoid and teres minor.

Question 194

DRESS syndrome can be caused by drug rxn to anticonvulsants (**phenytoin, carbamazepine), allopurinol, sulfonamides, and abx (minocycline, vancomycin). Pt present with fever, generalized lymphadenopathy, facial edma, and diffuse morbilliform skin rash that can progress to confluent erythemia with follicular accentuation. what will be elevated on labs?

Answer 194

eosinophilia! Can also affect liver (hepatomegaly, jaundice), kidney (Acute intersitital nephritis) and lung (cough dyspnea)

Question 195

administration of a drug can causes coronary steel syndrome = redistribution of blood flow away from ischemic areas, exacerbating existing MI. A drug that cause __________ effects is most likely to be associated with this phenomenon?

Answer 195

coronary arteriolar dilation (not systemic arterial dilation.)

Question 196

the most important limiting factor for left ventricular blood supply during a stress test is?

Answer 196

duration of diastole (that’s when ventricles fill)

Question 197

decreased numbers of functional T-Tubules in affected muscle fibers leads to?

Answer 197

uncoordinated contraction of myofibrils. This manifest as muscle weakness (limb girdle muscular dystrophy most likely in this question stem due to mutated sarcolemma protein (caveolin) affecting excitation contraction coupling). T-tubules allow for depolarization impulse to rapidly propagate through the interior muscle fiber. this ensures that calcium release from the sarcoplasmic reticulum occurs uniformly throught the fiber. allowing synchronized contraction.

Question 198

primary aldosteronism can present how?

Answer 198

muscle weakness and paresthesias (due to hypokalemic alkalosis), also HTN

Question 199

what Molecule is most likely involved in mediating te accumulation of pus?

Answer 199

IL-8. is a chemokine produces by macrophages, that induces chemotaxis phagocytosis in neutrophils. Other significant chemotactic agents includes: N-formylated peptides, leukotriene B4, 5-HETE (the leukotriene precursor), and component C5a. Trick - not Leukotriene C4.

Question 200

70 man. Presents for 3 weeks unrelenting low back pain. No trauma but describes having to strain to urinate. Has not seen a dr in 5 years. Tenderness in lower vertebral area. Imaging of spine shows osteoblastic lesions in lumbar vertebrae. WOTF is most likely part of the spread of this pts disease

Answer 200

prostatic venous plexus (not internal iliac lymph nodes.

Question 201

accentuated pulmonary component of the second heart sound and signs of right sided heart failure due to cor pulmonale. These manifestations represent?

Answer 201

pulmonary arteriole hypertension, can develop in pts with system sclerosis as a result of damage to the pulmonary arterioles (this pt had sclerodactyly) the cause of the pts presentation was **** intimal thickening of pulmonary arterioles.

Question 202

the MMR vacine for Rubella is what type of vaccine

Answer 202

live attenuated.

Question 203

during cardiac cath, puncture of the common femoral artery above the inguinal ligament increases the risk of ?

Answer 203

retroperitoneal hemorrhage, as this portion of the vessel lies directly inferior to the peritoneum. Note: retroperitoneal bleed cannot be controlled with external compression and –>. Lead to life threatening hemorrhage.

Question 204

a pt with retroperitoneal hemorrhage generally present with

Answer 204

significant hypotension, drop in hemoglobin, ipsilateral flank painl

Question 205

right paracolic gutter is a peritoneal recess found bw ascending colon and abd wall.

Answer 205

fluid bile pus blood typically accumulates here with GI organ pathology. (appendix, gallbladder)

Question 206

Interleukin-2 produced by T helper cells whats its function of IL-2

Answer 206

stimulates growth of CD4+ and CD8+ T cells and B cells (stimulation of division), activates NK cells and monocytes, the inc activity of T cells and NK cells is thought to be responsbile for IL-2 anti-cancer effect on metastic melanoma and RCC.

Question 207

what is the mechanism for stress urinary incontinence during pregnancy

Answer 207

increased intraabdominal pressure (from the gravid uterus that exceeds the pressure point that maintains closure of the urethral valve)

Question 208

zinc finger motifs ( around 30-35 AA bound around a zinc atom via linkage w/ cysteine and histidine residues. A receptor for WOTF hormones was most likely isolated?

Answer 208

thyroid hormone, also intracellular receptors that bind steriods, and fat soluble vits act directly as transcription factors and contain the zinc finger binding domains

Question 209

PPIs can inc or dec risk of osteoporotic fractures with longterm use?

Answer 209

inc risk. Bc strong acid suppressing meds may dec absorption of dietary calcium in GI tract..

Question 210

8 yo boy with fever, throat pain, severe dyspnea, tachypneae, inspiratory stridor, also worsening dysphagia w/ solid foods over pasted two weeks. On peripheral blood smear (blasts) immature hematopoietic cells. The neoplastic cells causing this condition normally given rise to what?

Answer 210

t-lymphocytes not B-lymphocytes. T-cell ALL often presents as a mediastinal mass that can cause respiratory symptoms, dysphagia (compression of esophagus from mass), or superior Vena cava syndrome. Not B cell ALL is most common cause of ALL. Other symptoms of ALL (fever, fatigue, pallor, petechiae, bleeding. if spread it can cause lymphadenopathy, hepatosplenomegaly and bone pain.

Question 211

what changes in bone structure do you expect in pt with primary hyperPTH

Answer 211

subperiosteal resorption (subperiosteal erosions in phalanges on hand, with cystic degeneration (osteitis fibrosa cystica), and granular salt and pepper skull

Question 212

contact drematitis, granulomatous inflammation, tuberculin skin test and the candida extract skin rxn (inject it under skin then see nodule). The response observed for all of theses is caused by what cell type?

Answer 212

T- lymphocytes (TH1) these are all examples of delayed type hypersensitivity reaction (DTH) . DTH are TH1 lymphocytes that release .interferon gamma to cause recruitment and stimulation of macropahges.

Question 213

regardless if your patient has a duodenal peptic ulcer or gastric ulcer. Biopsy at which site would show the infectious agent (H. pylori)?

Answer 213

gastric antrum!

Question 214

3 yo girl w/ several months of fatigue and difficuly walking. She ambulates normally at first but rapidly becomes weak and tired. Hx of mild motor delays, but otherwise developmentally normal. Normal vitals. Mild decreased power in all 4 extremities but no ataxia. 1/6 systolic murmur and S3 gallop. she is hypotensive and creatine kinase (304). muscle biopsy shows very low carnitiine content. which substance has deficient synthesis?

Answer 214

acetoacetate. (primary carnitine def) Carnitine def impairs FA transport from cytoplasm into mitochondria, preventing B-oxidation of FA into acetyl coa. This leads to cardiac and skeletal myocyte injury (lack of ATP from citric acid cycle) and impaired ketone body (acetoacetate) production by the liver during fasting periods (this is also seen in other FA oxidation disorders (medium- or very long chain acyl coa dehydrogenase def)

Question 215

4 yo white boy, difficulty walking. Hx of frequent respiratory infecitons. Cultured cells show high rate of radiation-induced genetic mutations. This pt is most likely experiencing?

Answer 215

cerebellar atrophy. This pt has Ataxia telangiectasia. Def in ATM gene –> failure to repair DNA double strand breaks –> cell cycle arrest. Triad: cerebellar defects (ataxia), spider angiomas (telangiectasia), IgA deficiency.

Question 216

in the retroperitoneum, the ureters pass posterior to the? And anterior to the? To reach the true pelvis

Answer 216

ureters pass posterior to the ovarian (gonadal) vessels. ANTERIOR to the common/external iliac arteries

Question 217

w/in the true pelvis the ureters lie Anterior to the _____ arteries. Medial to the ______?

Answer 217

ureters lie anterior to the * internal iliac artery and medial to the ovarian vessels. The uterine artery crosses over the ant surface of the ureter

Question 218

pt is being treated with polyethylene glycol or magnesiumcitrate (“osmotic laxatives). The moa in this pt is most similar to the pathophys of what GI disorder?

Answer 218

lactase def (its causes osmotic diarrhea)

Question 219

56 yo. Admitted w/ dehyrdration secondary to excess otuput from ileostomy. Pt had total colectomy. For the last 6 months, hes had inc output from the ileostomy and has been admited twice w/ similar episodes of dehydration. On the 2nd admin, he has r. flank pain, ,no renal calculi on xray, US of abdomen shows 4 mm stone in distal right ureter. what is the underlying mechanism leading to stone formation in this pt.

Answer 219

increased hydrogen ion excretion in kidney (not inc uric acid production). Pt has Recurrent epidosdes of dehydration due to ileostomy, patients with chronic diarrhea or those who have colectomy have reduced bicarb reabsorption from gut, –> state of chronic metabolic acidosis. the kidney compensate by increasing the excretion of hydrogen ions and reabsorption of bicarbonate in the collecting ducts. inc uric acid production would be caused moree from high cell turnover (malignancies, lymphoproliferative disorder) or inborn errors of metabolism (glucose-6- phosphate def)

Question 220

parents tell 14 yo they are getting a divorse. He now is unusually quit. He hardly speaks. The child avoids his parents bc he feels that they are angry with him. He acknowledges that they have not expressed anger toward him, but he “can sense it” what defense mechanism is this

Answer 220

projection (attributing ones own feeling to others)

Question 221

know what the left ventricular pressure volume loop looks like for Arteriovenous shunt

Answer 221

av shunt result from the formation of AV fistulas. it will dec TPR, (inc preload, dec afterload).

Question 222

women at 38 week uncomplicated pregnancy, has .gallstones. No abnormalities on US 1 year ago. What pathogenetic components is most likely contributed to this pts condition?

Answer 222

estrogen induced cholesterol hypersecreteion and progesterone induced gallbaldder HYPOmotility. Pregnancy and the usage of OCP predispose to gallstone formation. estrgoen inc cholesterol synthesis by upregulating hepatic HMG-CoA reductase actiivty, causing bile to be supersaturated w/ chcolesterol. progesterone dec bile acid secretion and slows gallbaldder empyting. (incorrect - estrogen induced bilirubin hypersecretion and cortisol mediiated cholesterol hypersecretion.

Question 223

study shows sudden inc in postopt infections in hospital, in pts operated on w/ surgic instruments sterilized by broken autoclave machine that only reached tep of 212. what bacteria is responsible?

Answer 223

clostridium perfringens ( spore forming bacteria, sporse can survive past boiling point)

Question 224

pt develops drug induced lupus (+ anti histone ab), hemglobin 12.5, platelets 120,000, leukocytes 11000. abnormality in what metabolic processes most likely underlies this pts current condition

Answer 224

liver acetylation. Drug induced lupus has been linked to drugs metabolized by N aceylation in the liver (procainamide, hydralazine, isoniazid). Genetically predisposed individuals who are slow acetylators are at greater risk

Question 225

most common pathogens causing nosocomial bloodstream infections?

Answer 225

Coagulase-negative staphylococci, staphylococcus aureus, enterococci, candida species. Question said study saw inc in staph BS infection is most likely related to inc use of? Intravascular devices (not surgical antiobiotic prophylasis)

Question 226

what is the most frequent mechanism of sudden cardiac death in the first 48 hours after acute MI,

Answer 226

Ventricular fibrillation (related to electrical instabillity in the ischemic myocardium)

Question 227

infant born to 26 yo mom, birthwt/length 10/15th%, protruding tongue, excessive skin at the nape of the neck, upslanting palpebral fissures. Startle reflex is weak. Harsh, III/IV systolic murmur over left sternal boarder (VSD). mom has had miscarrages what karyotyping would you see?

Answer 227

DOWNS syndrome most commonly causes by random meiotic nondisunction (47,XX,+21), answer was unbalanced roberstonian translocation with 46 chromosomes and 3 effective copies of chromo 21 **[46,XX, t(14;21)]

Question 228

60yo Er with Diplopia started hours ago. Long standing diabetes w/ pour glycemic control. PE: Right sided ptosis w/ R pupil in the inferolateral position (now u know its CN3), pupils are = size and reactive to light bilaterally (thus you know psns is still working bc no dilation in one eye). this condition is most likely due to?

Answer 228

Nerve ischemia. (diabetic CNIII mononeuropathy) WHY? Bc if it was due to nerve compression you would have parasympathetics injured first (dilated pupil “blown”) since it wraps the nerve. Classic presentation in diabetics w/ acute onset diplopia, and “down and out” position. also Ptosis occurs due to paralysis of levator palpebrae.

Question 229

why would you give someone with St seg elevations in the inferior leads (Inf MI) atropine

Answer 229

inf MI’s are often due to RCA blockage, the artery usually responsible for SA and AV node perfusion. Thus INF MI are often associated w/ bradycardia. ATROPINE blocks vagal influence on the SA and AV nodes and is effective in increasing HR.

Question 230

Gastric bypass surgery can cause small intestinal bacterial overgrowth(SIBO) due to excessive bacterial proliferation in blind-ended Gastroduodenal segment. SIBO results in a def in? and a Inc production of?

Answer 230

def: most vitamins (B12, A,D, E) and IRON, But an increase production of FOLIC ACID and Vit K

Question 231

cleft lip results from failure of what intrauterine process?

Answer 231

fusion of the maxillary prominence and intermaxillary segment (not fusion of the 2 medial nasal prominences (which forms the intermaxillary segment) this is associated with severe midline defect like holoprosencephaly)

Question 232

decribes the lip and palate formation during fifth-sixth week of embryo development,

Answer 232

a series of fusions: 1. the 1st pharyngeal arch splits into upper maxillary prominence and lower mandibular prominence. 2 fusion of the 2 medial nasal prominences forms the midline intermaxillary segment (forms the philtrium of the upper lip, the 4 medial maxiallary teeth, and the primary palate) 3. the left and right maxiallary prominences then fuse with the midline intermaxillary segment to form the upper lip and primary palate. if one of the maxillary prominences fails to fuse with the intermax segment, a unilateral cleft lip occurs.

Question 233

spider angiomata are subcutaneous vascular lesions. Whats the pathogensis

Answer 233

occur in hyperestrogenic states (pregnancy, liver failure/cirrhosis) possibly due to estrogens effects on arteriolar dilation. The # of lesions usually correlate to severity of liver disease

Question 234

pt with distal duodenal ulcer and high normal gastrin levels that rise in response to secretin administration (should fall) are suggestive of?

Answer 234

zollinger-Ellison syndrome. This condition is caused by gastrin secreting tumors (gastrinomas) often malignant located in small intestine or pancreas. The inc gastring –> parietal cell hyperplasia–> inc gastric acid secretion –> peptic ulcers, heart burn, and diarrhea (excess gastric acid impairs intestinal epithelial cells and digestive enzymes)

Question 235

ciliated mucosal epithelium lines from the trachea to the? The terminal bronchioles are covered by?

Answer 235

ciliated mucosal epi (trachea –> proximal portion of the respiratory brochioles). The terminal bronchioles are coverd by ciliated cuboidal epi, and club cells

Question 236

a pt with abnormal sexual differentiation. Karotype analysis shows 46XY genotype, bipsy of gonadal tissue shows a lack of sertoli cells but normally functioning leydig cells. What phenotypes is most likely present for internal reproductive organs and external genitalia

Answer 236

female and male for internal reproductive organs, Male for external genitalia (leydig cells –> testosterone (wolffian duct to male internal genitalia) –> DHT (genital tubercle/urogenital sinus –> Male external genitalia) SRY gene on the Y chromo codes for Testes determining factor –> allows development of testes. Absent Sertoli cells then no AMH (no mullerian duct involution) thus you get development of internal female reproductive organs (fallopian tubes, uterus, cervix, upper vag)

Question 237

pt presents with dyspnea and chronic exertional angina, is evaluated for Coronary revascularization. Echo shows hypokiinesia of ant wall of left vent and LVEF of 35%. After coronary artery bypass grafting. 10 days after echo shows no hypokinesia and LVEF inc to 50%. what best explains the changes in cardiac contractility and wall motion.

Answer 237

hibernating myocardium refers to a state of chronic myocardia ischemia. In which both myocardial metabolism and function are reduced to match a concomitant reduction in coronary blood flow

Question 238

guy goes on binge drinking and now presents with glucose of 35mg/dl, urine is strongly positive for ketones. Suppression of what is the primary cause of this pts hypoglycemia

Answer 238

gluconeogenesis. Ethanol is metabolized leading to dec NAD+/ANDH and increases the NADH/NAD ratio. This INHIBITS all other pathways requiring NAD+, such as gluconeogeneiss (lactate cant be converted to pyruvate, and excess NADH inhibits conversion of malate to oxaloacetate.

Question 239

pt with a cystic mass (showed a CT) in the Left cerebellum, you would expect what on clincial exam?

Answer 239

left dysdiacdochokinesia (cant do rapid alternating movements)

Question 240

pt with hx of substance abuse presents w/ depression, fatigue, hypersomnia, hyperphagia, vivid dreams. What kind of withdraw

Answer 240

Cocaine

Question 241

young tall thin male pt with primary spontaneos pneumothroax is most likely caused by?

Answer 241

apical subpleural bleb

Question 242

pt had abortion 2 days ago. Present with sudden fever, abd pain, uterine tenderness, foul smelling vaginal discharge. What microbe is responsible.

Answer 242

staph aureus in septic abortion (it is the most common.

Question 243

cytokeratins can be used as a marker for what kind of tissue derived tumors

Answer 243

epithelial derived tumors (beast cancer) since its squamous

Question 244

Vimentin is an intermediate filament present in what kind of tissue and can be used to detect what type of tumors

Answer 244

Mesenchymal tissue, sarcomas

Question 245

Myeloperoxidase is a peroxidase enzyme that can be used as a marker for what type of cells and tumors

Answer 245

myeloid cells, such as those in acute myeloid leukemia

Question 246

chromogranin A and synaptophysin are markers used for what tumors

Answer 246

neuroendocrine

Question 247

50yo no smoker is found to have a round lesion in RUL of lung. What would favor the diagnosis of Hamartoma?

Answer 247

Hamartoma (pulmonary condroma) = mc benign lung tumor, usually found incidentally as solitary lung nodule (coin lesion). Cartilage tissue in the biopsy sample: lung is most common location and contain islands of mature hyaline cartilage, fat, smooth m and clefts lined by respiratory epithelium

Question 248

pt with RA. This PT’s serum is most likely to contain IgM antibodies against what substancE?

Answer 248

Fc portion of human IgG = Rheumatoid factor ( IgM antibody specific for Fc component of IgG) RA result from immune response against autoantigens in joints. Infiltrating CD4 T cells secrete cytokines that promote inflammatory synoviits. They also stimulate B cells to produce the RF and anti-citrullinnate protein abs

Question 249

pt that’s on chemo presents with fever, chest pain, cough, dyspnea, and hemoptysis, chest xray: consolidation, nodules or cavitary lesions “dense infiltrate in RUL lobe”. Bronchoscopy grow mold. Whats the cause?

Answer 249

aspergillus fumigatus

Question 250

inc pressure in what vein can be causing bleeding spot within a cluster of enlarged tortuous veins in the gastric fundus

Answer 250

splenic vein. Bc the short gastric veins drain the fundus of the stomach into the splenic vein.

Question 251

what is the major virulence factor in H. Influenza type B causing epiglottis

Answer 251

Polyribosylribitol phosphate (is a capsule component and major virulence factor.

Question 252

in western nations. A successful hepatocellular carcinoma prevention strategy in these countries would focus on incorporating?

Answer 252

universal vaccination (hep B = 85% of al HCC)

Question 253

pt presenting with upper limb pain/weakness, and ipsilateral ptosis and miosis (horners) are highly suggestive of?

Answer 253

pancoast tumor! (which are usually non small cell lung cancers: Squamous cell carcinoma, adenocarcinoma), arise near the superior sulcus. : pt with shoulder pain, upper limb paresthesias, areflexic arm weakness due to brachial plexus involvement

Question 254

pt with limb pain weakness in upper limb, shouder pain, ipsilateral ptosis and miosis, smoker, you diagnosis pancoast tumor. This pts lesion is most likely where?

Answer 254

autonomic ganglia ( cervical sympathetic ganglia) bc she has horners syndrome due to this tumor.

Question 255

when you inset a chest tube into 5th IC space in midaxillary line. What muscle is dissected during procedure

Answer 255

serratus anterior

Question 256

meds associated with osteoporotic fractures

Answer 256

anticonvulsants that induce CYP450 (inc vit D catabolism), Aromatase inhibitors and medroxyprogesterone ( dec estrogen), GnRH agonists (dec testo, estrogen), PPI (dec calcium absorption), Glucocorticoids (dec bone formation) hyperthyroidism ( or over replacemnet of Thyroid hormone (levothyroxine) can lead to osteoporosis)

Question 257

thymidine kinase gene mutated in HSV 2 resistant strain is cultured in a cell line and is coinfected w/ a nonresistant HSV 1 strain. Its found that some newly type 1 virions acquire resistant to acyclovir, and subsequent progeny continue to be resistant. what is this called?

Answer 257

recombination (gene exchange that occurs through the crossing over of 2 DS DNA molecules

Question 258

mixing of genome segments in segmented viruses that infect the same host cell, (changes in genomic composition that occur when host cells are coinfected w/ 2 segmented viruses that exchange whole genome segments . This is referring to ?

Answer 258

reassortment

Question 259

guy with AAA. No syphilis. What pathologic condition is most likely underlying cause?

Answer 259

chronic transmural inflammation ( AAA is associated w/ (>60, smoking, htn, male, fam hx) –> oxidative stress, vascular smooth m apoptosis, and chronic transmural inflammation of the aorta. Inflammatory cells (macrophages) release matrix metalloproteinases and elastases that degrade extracellular matrix components (elastin, collagen) –> weakening and progressive expansion of the aortic wall

Question 260

guy w/ malig melanoma. Immunohisto indicates malignant cells have decreased integrin expression. These cells are most likely to exhibit poor adhesion to what component of the extracellular matrix?

Answer 260

fibronectin (also collagen and laminin). Integrins are transmembrane protein receptors that interact with extracellular matrix by binding to specific proteins listed. Note cadherins, selectins, and Ig superfamily members are other adhesion molecules

Question 261

what is fibronectin

Answer 261

large glycoproteins produced by fibroblasts and some epithelial cells. Function to bind integrins, matrix collagen, and glycosaminoglycans. Serving as a mediator of cell adhesion and migration.

Question 262

what is the main mechanism of excess copper removal in a healthy human body

Answer 262

hepatic excretion into bile

Question 263

pt with mild intellectual disability, lymphedema, short stature, webbed neck, and 2 karyotypes (40% of cells have 45,X genotype, and remaining contain 46XX) which of the following is the cause of this pts condition?

Answer 263

somatic mosaicism (mosaic turner syndrome) mosiacism is the presence of multiple, genetically different cell lines within the body. It can result from severe processes, including chromosomal nondisjunction and mutations during the first stage of embryonic development.

Question 264

what is somatic mosaicism

Answer 264

affects the cells forming the body, causing disease manifestations to develop in affected individuals. 45,X/46XX is the most commonly diagnossed mosaicism affecting sex chromosomes

Question 265

what is germline mosaicism

Answer 265

affects the cells that give rise to gametes, allowing the affected genes to pass to the offspring. Chance of child being affected depends on proportion of gametes that carry the mutation. * when mosaicism is limited to germline, the affected parent does not develop clinical manifestations.

Question 266

a pt is treated for N gonorrhoeae and devlops antibodies against the bacterial pili. His GF isnt treated and now he gets reinfected. Whats the reason for the lack of long lasting immunity against the bacteria despite antibody formation

Answer 266

antigenic variation of the pili

Question 267

46 yo man comes to ER for recurrent nose bleeds. Pt has a hx of alcohol abuse and chronic mental illness. He is drunk, PE: swollen gums, scattered ecchymoses, and hyperkeratosis. Has a chronic ulcer on left lower extremity that does not appear to be infected. what is the mechanism for this pts findings ?

Answer 267

clostridium perfringens ( spore forming bacteria, sporse can survive past boiling point)