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uWorld Flashies > uWorld 16 > Flashcards

uWorld 16 Flashcards

1
Q

when is a mutation in copper-zinc superoxide dismutase (SOD1) seen

A

ALS

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2
Q

what is the MOA of Riluzole

A

decreases glutamate release (reducing glutamate toxicity)

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3
Q

what cases genetic/antigenic shift in influenza A

A

REASSORTMENT of genomic segments of the HUMAN strain with the genomic segments of the ANIMAL (particularly avian) strain

reassortment only happens in SEGMENTED genomes

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4
Q

what causes antigenic drift

A

point mutations in HA and neuraminidase genes that slightly alter the protein products

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5
Q

what is transformation (bacteria and virus)

A

bacteria: uptake of naked DNA by pro or eukaryote
virus: incorporation of viral DNA into the host cell chromosome

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6
Q

there are the telomeres of a chromosome

A

3’ END OF CHROMOSOME (TTAGGG repeats)

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7
Q

what activates RAS in the Ras-MAPK pathway

A

a growth factor ligand binding to a RECEPTOR TYROSINE KINASE located on the cell membrane (which autophosphorylates the receptor)

Ras-GTP is the active form and activates RAF, which activates MAP kinase kinase which activates MAP kinase, which actives gene transcription

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8
Q

Nef and Tat are viral HIV proteins that do what

A 
Tat gene: role in viral replication
Nef gene: decreases expression of MHC class 1 proteins on the surface of infected cells
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9
Q

postural skeletal muscles such as the soles and paraspinal muscles contain predominately what kind of muscle fibers

A

Type 1 slow twice, red muscle fibers that derive ATP primarily from oxidative (aerobic) metabolism- thus they have HIGH MYOGLOBIN (oxygen storage) and MITOCHONDRIAL (aerobic respiration) concentrations

Type 1 fibers perform actions requiring low-level sustained force

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10
Q

describe type II muscle fibers

A

specialized for generations rapid forceful pulses of movement
Type IIb- derive ATP energy through anaerobic glycogenolysis and subsequent glycolysis
Type IIa (“FAST TWICTCH”): fibers are intermediate b/w type I and type IIb fibers- generate ATP via aerobic metabolism

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11
Q

what is the issue in I-Cell disease

A

deficient phosphorylation of mannose residues on certain glycoproteins in the Golgi apparatus
defect in PROTEIN TARGETING to LYSOSOMES
PHOTOTRANSFERASE ENZYME catalyzes the phosphorylation of mannose residues on lysosome-bound proteins

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12
Q

what is odynophagia and what does it suggest in the presence of GERD

A

pain with swallowing

presence of odynophagia usually indicates the progression to EROSIVE ESOPHAGITIS and the formation of an ULCER

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13
Q

where is resistance maximal in the lungs

A

2nd to 5th generation airways, including the segmental bronchi

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14
Q

ECG showing ST elevation in leads I and aVL w/ elevated cardiac enzymes would likely show occlusion of what artery

A

LEFT CIRCUMFLEX ARTERY (supplies LATERAL aspect of LEFT ventricle)
I and aVL are LATERAL LIMB LEADS (so are V5-V6)

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15
Q

what ECG findings are indicative of proximal LAD occlusion, what about distal LAD

A

proximal LAD: V1-V4 (anterior chest) leads are involved

distal LAD: V3-V4 are involved (V1-V2 are spared)

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16
Q

the LAD supplies what part of the heart

A

anterior aspect of left ventricle and interventricular septum

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17
Q

what ECG findings would be expected if the left main coronary were occluded

A

anterolateral infarction

ST elevation in the anterior (V1-V4) and lateral (V5-V6, I and aVL)

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18
Q

what ECG findings would be expected if the right coronary artery were occluded

A

supplies right ventricle and inferior aspect of the left ventricle
ST elevation in the inferior leads (II, III, and aVF)

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19
Q

what is the difference b/w absolute and relative polycythemia (erythrocytosis)

A

absolute has an INCREASE in total RBC MASS

relative has a NORMAL RBC mass

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20
Q

what is the difference b/w primary vs secondary erythrocytosis

A

serum EPO is LOW in PRIMARY erythrocytosis

EPO is HIGH in SECONDARY

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21
Q

what causes secondary erythrocytosis

A

chronic hypoxia from: high altitudes, smoking, COPD

abnormal secretion from neoplastic or otherwise diseased tissues

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22
Q

what defines hypoxic secondary erythrocytosis

A

SaO2 less than 92%

PaO2 less than 65mmHg

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23
Q

what innervates the posterior part of the external auditory canal

A

VAGUS NERVE (via small auricular branch)

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24
Q

what is VASOVAGAL SYNCOPE

A

passing out after stimulation of the posterior external auditory canal by an otoscope examination
parasympathetic outflow via vagus nerve leads to decreased heart rate and blood pressure

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25
Q

how does biliary atresia present

A

baby healthy at birth, but the present with JAUNDICE within the FIRST 2 MONTHS of life, along with DARK URINE, and ACHOLIC (pale or clay-colored) STOOLS
firm hepatomegaly due to inflammation
ELEVATED DIRECT BILIRUBIN and GGT (consistent with cholestasis)

26
Q

what is seen on liber biopsy of biliary atresia

A

intrahepatic bile duct PROLIFERATION
portal tract edema
fibrosis
urgent surgical intervention is required

27
Q

what is Gilbert syndrome

A

problem with glucuronidatio not bile
usually asymptomatic except at times of STRESS (FASTING, ILLNESS) during which mild
indirect hyperbilirubinemia and jaundice

28
Q

breast milk jaundice is what

A

indirect hyperbilirubinemia that peaks at age 2 weeks
enzyme is BETA-GLUCURONIDASE and it deconjugates bilirubin
leads to increased absorption and therefore, increased enterohepatic circulation of bilirubin
urine and stool appear unaffected

29
Q

what is the order of enzymes involved in base excision repair

A

glycosylase (cleaves the altered base leaving an AP site), endonuclease (cleaves 5’ end), lyase (cleaves 3’ sugar phosphate), polymerase (fills single nucleotide gap), ligase (seals nick)

30
Q

excessive consumption of what can promote the deamination of cytosine, adenine, and guanine to form uricil, hypoxanthine, and xanthene (respectively)

A

DIETARY NITRATES

31
Q

what is base excision repair used to correct

A

single-base DNA defects induced spontaneously or by exogenous chemicals

32
Q

what lab abnormalities are seen in SLE

A

anemia, leukopenia, thrombocytopenia
Positive ANA, and ANTI-dsDNA, anti-Sm (snRNP)
LOW COMPLEMENT LEVELS (C3 and C4), increased IMMUNE COMPLEXES

33
Q

what constellation of features is typical of new-onset SLE

A

“butterfly” rash
inflammatory arthritis
ULCER of hard palate

34
Q

how does isoniazid resistance occur

A

decrease in bacterial expression of the catalase-peroxidase enzyme that is required for INH activation
modification of the protein target binding site for INH

35
Q

if the left temporal hemiretina is fucked what geniculate nucleus is fucked and what other structures are affected

A

LEFT the temporal hemiRETINA stays on the side of origin

left lateral optic chiasm, optic tract, LGN body, optic radiations, and primary visual cortex

36
Q

HPV has a predilection for what cells and where are these found in the respiratory tract

A

STRATIFIED SQUAMOUS EPITHELIUM found in anal canal, vagina, and cervix
TRUE VOCAL CORDS are the only area in the resp tract with this

37
Q

what is seen on LM of actinic keratosis

A

hyperkeratosis (hyperplasia of the stratum corneum)
parakeratosis (retention of nuclei in the stratum corneum)
atypical keratinocytes w/ pleomorphic nuclei and multiple mitosis

38
Q

actinic keratosis transform into what

A

Squamous Cell Carcinoma

39
Q

what is the most common skin cancer

A

basal cell carcinoma
arises on sun-exposed skin and has a very low tendency to mets
presents a pearly papule w. central depression or ulceration
histo: NESTS of BASALOID cells and peripheral PALISADING of nuclei

40
Q

what is a dermatofibroma

A

superficial benign fibrous hitiocytoma
result from the benign proliferation of fibroblasts
commonly arise ont eh lower extremities as a solitary nodule

41
Q

psoriasis presents how

A

hyperkeratosis plaques that affect the scalp, knees, and elbows
characterized by CLUBBED RETE RIDGES, HYPERKERATOSIS, NEUTROPHILS in the status CORNUM, perivascular lymphocytic infiltrates

42
Q

the parietal pleura generally extends how far blow the visceral pleura

A

2 ribs

43
Q

what are the boarders of the visceral pleura

A

6th rib along midclavivular line (so parietal goes to 8)
8th along midaxillary (so parietal goes to 10)
10th along the paravertebral line (so parietal goes to 12)

44
Q

parvovirus B19 infects what cells

A

erythrocytes precursors in the bone marrow

45
Q

how can organisms develop resistance to aminoglycosides

A

amino glycoside-modifying enzymes (acetyl, adenyl, or phosphate groups are added to the amino glycoside antibiotic outside the bacterium)
mutated ribosomal subunit protein
mutated porin protein

46
Q

if an enterococcus gets resistance to a drug by producing an enzyme that is involved in ACETYL group transfer to exogenous substances and is located on the surface of the cytoplasmic membrane what drug is it resistant to

A 
an AMINOGLYCOSIDE (gentamicin)
this is an AMINOGLYCOSIDE-MODIFYING ENZYME
47
Q

how do quinolone get resistance

A

mutated DNA Gyrase or topoisomerase

impaired influx/increased efflux

48
Q

how do enterocci get resistance to penicillin

A

mutated PBP

beta-lactamase production

49
Q

how doe tetracyclines get resistance

A

impaired influx/ increased efflux

inactivated enzyme

50
Q

why is Hep C so chronic

A

RNA-dependent RNA pol has NO PROOFREASDING 3’ to 5’ exonuclease activity, which results in many errors
hyper variable genomic regions- like those for envelope glycoprotein

51
Q

what immunohistochemical stains are used of endothelium

A

CD34 and von Willebrand’s factor

among others

52
Q

what are the initial symptoms of Picks Disease (frontotemporal dementia)

A

personality and behavioral changes (apathy, socially inappropriate behavior)
seen in early 50s or 60s
AD inheritance in 20-40% of cases

53
Q

damage to the hippocampus results in what

A

inability to form new memories (anterograde amnesia)

one of first regions to suffer damage in Alzheimer’s

54
Q

what is Gerstmann Syndrome

A 
Damage to the inferior parietal lobe of the dominant hemisphere:
right/left confusion
dysgraphia
dyscalculia
finger agnosia
55
Q

damage of sub thalamic nuclei causes what

A

contralateral hemiballismus

56
Q

99m Tc-pertechtonate has an affinity for what and is used for what

A 
parietal cells (including ectopic sites)
used for Meckel Diverticulum
57
Q

failure of proper descent during development of the hindgut can lead to what

A

imperforate anus

58
Q

what are lentigines

A

seen in lentigo

small tan or brown macule most often seen on the sun-exposed skin of a middle-aged or elderly person

59
Q

what drug do you use in someone with MRSA who is allergic to vanc

A

Daptomycin- depolarizes cellular membrane by creating transmembrane channels
ADRS: myopathy and CPK elevation
KEY: INACTIVATED BY SURFACTANT

60
Q

what is the MOA and ARDs of linezolid

A

MOA: inhibits 23S ribosomal RNA of the 50S
ADRs: optic neuritis, thromboyopenia, increased risk of serotonin syndrome

uWorld Flashies (62 decks)

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