test #36 4.27 Flashcards Preview

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Flashcards in test #36 4.27 Deck (123)
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1
Q
4 A's of Ataxia-telengectiasia
A
B & T cell immunodeficiency
autosomal recessive

- ATM gene (repair double stranded breaks)
- spider Angiomas
- IgA deficiency (bc need double stranded DNA breaks for class switching)
- increased AFP

radiation sensitivity, recurrent sinopulmonary infxn

also increased risk of hematological malignancy
2
Q
bare lymphocyte syndrome
A
autosomal recessive form of SCI

immunodeficiency resulting form a defect in expression of HLA class II antigens on APC

no MHC class II to present foreign antigens to T cells & have both cell mediated & humoral response
3
Q
how does cisplatin exert chemotherapeutic effects? how can this be prevented (2 ways)
A
generates reactive oxygen species that can cross-link DNA

1. amifostine = free radical scavenger. can prevent nephrotoxity and acoustic nerve damage.

2. establishing chloride diuresis (IV normal saline) bc cisplatin stays in nonreactive state when in high Cl- concentration
4
Q
N-acetylcysteine for influenza, bronchitis, cystic fibrosis?
A
mucolytic agent
-cleaves DISULFIDE bones in mucous glycoproteins

also
-enhances glutathione production
-conjugates NAPQI
-prevents radiocontrast-induced nephropathy

4 main effects
5
Q
filgrastim
A
G-CSF analong.

stimulate prolif and diff of granulocytes
6
Q
fomepizole
A
antidote in methanol (rubbing alcohol) or ethylene glycol (antifreeze) posioning

competitive antagonist of alcohol dehydrogenase (prevents conversion into toxic metabolites)
7
Q
methanol is in..
A
rubbing alcohol
8
Q
ethylene glycol is in...
A
antifreeze
9
Q
dexrazoxane
A
iron-chelating agent, help prevents anthracycline-induced (doxorubicin) toxicity

CHF
10
Q
anthracycline fxn
A
generate free radicals --> intercalate DNA --> cause breaks

antitumor antibiotic
11
Q
congenital hypothyroidism (cretinism)
A
6 P's
- pot-bellied
- pale
- puffy-faced (myxedema -- edema of skin and subcut fat)
- protruding UMBILICUS
- protuberant TONGUE
- poor brain development

mental retardation, short, coarse facial features, prolonged jaundice, hypotonic

increased incidence of congenital heart defects like ASD and VSD
12
Q
what can cause congenital hypothyroidism (4)
A
-maternal hypothyroidism,
-thyroid agenesis,
-thyriod dysgenesis (most common in US
- dyshormonogenic goiter
13
Q
4 general effects of thyroid hormones
A
4 B's
1. brain maturation
2. bone growth (increased osteoclast activity
3. b-adrenergic (upregulate B1 in heart)
4. increased BMR
14
Q
phenothiazine
A
antipsychotic / antihistamine

block D2 receptor --> relieves inhibition --> cause hyperprolactinemia at certain doses
15
Q
how does dopamine inhibit prolactin secretion?
A
binds to D2 receptor on prolactin-producing cells
16
Q
competence defined as..
A
ability to understand a situation and the possible CONSEQUENCES of decisions made in a situation
17
Q
who makes medical decisions if there is no next of kin?
A
judge / court will appoint a guardian to act on the patient's behalf

[hospital ethics committee makes recommendations, but cannot act]
18
Q
describe how sunlight increases vitamin D
A
7-dehydrocholesterol (provitamin D3) in skin absorbs UVB --> opens up B-ring, forming previtamin D3 --> undergoes isomerization induced by heat to form vitamin D3 (cholecalciferol)

physiologically-produced D3 or plant-derived D2 undergoes the 2 hydroxylation steps

1st: cytochrome P450 enzyme 25-hydroxylase converts vitamin D into 25-hydroxyvitamin D (calcidiol)

2nd: 1-alpha-hydroxylase in kidney converts calcidiol to calcitriol (active vitamin D3)
19
Q
how is excess 1,25-vitamin D dealt w/
A
kidney has enzyme 24 hydroxylase, converts 25 hydroxy-vitamin D to inactive 24,25 dihydrox vitamin D
20
Q
vitamin D2. vitamin D3. cholecalciferol. calcidiol. calcitriol. 24,25-dihydrocholecalciferol
A
-vitamin D2: plant-derived
-vitamin D3: cholecalciferol; physiologically produced

-calcidiol: 25-hydroxy vitamin D
-calcitriol: 1,25-dihydroxy vitamin D
21
Q
precision and reliability
A
essentially equivalent. low variability when measuring same thing.
22
Q
PCA territory? symptoms expected?
A
- contralateral hemianopia w/ macular sparing
- contralateral paraesthesia & numbness: face, trunk, limbs (involvement of lateral thalamus)

-cranial nerves III and IV (midbrain)
-lateral thalamus
-medial temporal lobe
- splenium of corpus callosum
- parahippocampal gyrus
- fusiform gyrus
- occipital lobe
23
Q
ACA covers..
A
-frontal: inferior and medial
-parietal: medial
- anterior 4/5 of corpus callosum
- olfactory bulb and tract
- anterior basal ganglia (caudate)
- anterior limb internal capsule
24
Q
anterior choroidal
A
last branch off internal carotid before it trifurcates.

supplies posterior limb of internal capsule, optic tract, LGN, choroid plexus, uncus, hippocampus, amygdala
25
Q
artery of percheron
A
branches off either right or left of PCA.

supplies bilateral thalami and dorsal midbrain

rare normal variant, seen in patients w/ bilateral thalamic or dorsal midbrain stroke
26
Q
MCA covers
A
- lateral convexity of frontal, parietal, temporal lobe
- deep subcortical structures, like internal capsule, basal ganglia.

usu contralateral motor & sensory defects
27
Q
exogenous cortisol suppresses what part of HPA axis?
A
all! CRH, ACTH, and cortisol

bilateral adrenal cortical atrophy
28
Q
unilateral of adrenal cortex can result from..
A
adrenocortical adenoma

autonomous production of cortisol from one adrenal gland suppresses CRH, ACTH. less stimulation of the OTHER gland.
29
Q
triggers for atopic dermatitis? presentation in young children? older children
A
chronic inflammatory skin disorder. HALLMARK: intense pruritus (if not itching, not AD)

CHILDREN!

triggered by:
environmental antigens
- FOOD, irritants

usu present by 5 y/o:
red, weeping/crusted lesions involving face, scalp, extensor surfaces. diaper area usu spared.

older:
manifests as lichenification in flexural distribution (neck, wrists, antecubital, popliteal fossa)
30
Q
cause of atopic dermatitis
A
mutations affecting proteins like filaggrin or other components of epidermis (impairment of skin's barrier function)

--> increases immunologic exposure to environmental allergens & microbial antigens --> immune HSR.

patients have:
1. high serum levels of IgE,
2. peripheral eosinophilia,
3. high cAMP phosphodiesterase in leukocytes
31
Q
allergic triad
A
allergic rhinitis
asthma
atopic dermatitis
32
Q
gluten enteropathy & dermatitis herpetiformis presentation
A
usually in 4th-5th decades of life. UNCOMMON in children!

pruritic vesicles & plaques on buttocks & extensor surfaces.
33
Q
erythematous, well-demarcated papules and plaques w/ silvery scale
A
psoriasis
34
Q
dermatitis herpetiformis vs. atopic dermatitis
A
atopic dermatitis: usu kids

dermatitis herpetiformis: usu presents in 4th-5th decade of life, uncommon in kids.
35
Q
acute viral hepatitis on hepatocyte (2)
A
1. hepatocyte injury
2. hepatocyte death
36
Q
travel to foreign country (overcrowing & poor sanitation) & return w/ liver problems
A
think acute hepatitis A
37
Q
hepatocyte injury vs. hepatocyte death
A
injury: ballooning degeneration
- cytoplasm appears empty w/ only occasional eosinophillic organelle remnant remaining

death: lobular architecture disruption, cytolysis, apoptosis, confluent hepatocyte necrosis.

damage attracts mononuclear inflammation in sinusoids & portal tracts
38
Q
bridging necrosis
A
regions of adjacent lobules are interconnected by swatches of dead hepatocytes
39
Q
presentation of viral A hepatitis
A
acute.

fever, malaise, fatigue, anorexia, nausea & vomiting, mild abdominal pain.

DARK URINE = increase serum bilirubin.

hepatomegaly & jaundice
40
Q
prolonged pruritus and fatigue suggests
A
primary sclerosing cholangitis (diffuse inflammation and fibrosis of biliary tract)

recall pruitus -- bile acid mediated
41
Q
acholic stools and bone pain suggests
A
chronic cholestatis process, like primary biliary cirrhosis
42
Q
liver lobule
A
functional anatomical unit of liver.

hexagonal structure centered on central vein

portal triad at each corner
43
Q
liver acinus
A
diamond connecting 2 central veins (across) and 2 portal triads (vertically) of 2 different lobules

creates 'zones' of oxygenation

zone 1: vertical closest to 2 portal triads.
- oxygen dependent processes (gluconeogenesis, beta oxidation, cholesterol synthesis)
- site of viral hepatis

zone 3: closest to each central vein
- metabolic toxin removal (p450 system)

- site of alcoholic hepatitis
44
Q
acute hepatitis primary affects what part of liver? chronic?
A
acute: lobule & portal tract

chronic: predominantly portal tract
45
Q
formula for resistance
A
R = nL / r^4

n = viscosity
L = length
r = radius
46
Q
facies of potter syndrome
A
suborbital creases
depressed nasal tip
low set eats
retrognathia
47
Q
common intraabdominal infections (i.e. post perforated appendix)
A
usu polymicrobial:
1. b. frag
2. ecoli

most common
48
Q
candida can be isolated from an intraabdominal infection related to.
A
perforation of proximal bowel, like perforated peptic ulcer
49
Q
what does EBV bind to in order to enter cell?
A
CD21 on B-lymphocytes

EBV glycoprotein gp350 binds to C3d complement component receptor CD21
50
Q
where is CD21 expressed
A
1. B cell surface
2. nasopharyngeal epithelial cells
51
Q
how does parvovirus enter erythroid cells
A
blood group P antigen

expressed on mature erythrocytes, erythroid progenitors, megakaryoctes, palcenta, fetal liver and heart

immature erythroid cells most vulnerable (adult bone marrow & fetal liver are principle targets)
52
Q
how does CMV bind to cells
A
like other herpesvirus, via glycosaminoglycans
53
Q
how does adenovirus enter cells
A
rodlike structures from its penton base capsomeres mediate adsorption to host cells.

receptor: transmembrane protein member of immunoglobulin superfamily
54
Q
kozack sequence
A
on mRNA
initiator for translation

gcc(A or G)ccAUGG

purine 3 bases upstream AUG = very important
55
Q
shrine dalgarno
A
8bp upstream AUG

help recruit ribosome to mRNA
56
Q
3 steps of translation (note where energy is used)
A
1. initiation (IF, uses GTP)
- assemble 40s subunit w/ initiator tRNA. wait for mRNA & 60s to bind

2. elongation
- charged tRNA (used ATP) binds
- ribozyme catalyzes peptidyl-transferase (no energy)
- translation of ribosome 3 nucleotides towards 3' end of mRNA (uses GTP and EF2)

3. termination, stop codon -- recognized by release factor. polypeptide released
57
Q
what are the three end products of the nonoxidative (reversible) part of HMP shunt
A
1. ribose 5-phosphate
2. glyceraldehyde 3-phosphate
3. fructose 6-phoshate
58
Q
NADPH vs. NADH
A
NADPH used as reducing equivalent in cytosol

NADH used as energy source for ATP synthesis (electron transport chain)
59
Q
how can ribose be synthesized by fructose-6-phosphate or glyceraldehyde-3-phosphate
A
ribose 5-phosphate glyceraldehyde 3-phosphate
(via transketolase)

[simultaneously xylucose 5-phosphate sedoheptulose 7-phosphate]

glyceraldehyde 3-phosphate fructose 6-phosphate
(via transaldolase)

[simultaneously sedoheptulose 7-phosphate erythrose 4-phosphate
60
Q
what reaction do transketolase do? transaldolase?
A
transketolase: transfers 2 carbon groups

transaldolase: transfers 3 carbon groups
61
Q
which cells produce NADPH (3 main uses)
A
1. NADPH consumed in fatty acid & steroid synthesis.
2. cytochrome p450 pathway
3. generation of superoxide in phagocytes

so liver, adrenal cortex, gonads, adipose tissue, erythrocytes
62
Q
making MPO in phagocytes
A
1. NADPH oxidase (O2-> superoxide
2. superoxide dismutase (superoxide -> hydrogen peroxide
3. myeloperoxidase (hydrogen peroxide -> MPO)
63
Q
enolase
A
converts 2-phosphoglycerate -> phosphoenolpyruvate in glycolysis
64
Q
aconitase
A
citrate -> isocitrate in TCA
65
Q
green pigment in echhymoses
A
biliverdin

heme -> biliverdin
via HEME OXYGENASE
66
Q
continuous leuprolide on testosterone and DHT levels
A
concordant transient increase, followed by decrease in both
67
Q
B12 + R protein? B-12 + intrinsic factor
A
R protein protects B12 from acid in stomach (released by pancreatic enzymes

intrinsic-factor protects B12 from pancreatic proteolysis + permits absorption in terminal ileum (bind to intrinsic factor receptor
68
Q
r protein
A
haptocorrin -- made in salvia
-binds B12, protects from stomach acid

degraded by pancreatic enzymes
69
Q
most cases of B12 deficiency
A
unrelated to intake.. usu poor absorption.

b12 often needs to be taken parenterally
70
Q
elderly patient w/ chronic anemia and unknown underlying cause?
A
prob B-12 malabsorption.

elderly:
-poor absorption due to gastric atrophy --> achlorhydia and decreased release of B12 from food proteins
- also pernicious anemia can be common in elderly
- or terminal ileal disease (IBD)
- or bacterial overgrowth syndrome
71
Q
in what form is diet more readily absorpbed
A
dietary meat: iron in heme form --> more readily absorbed

iron from vegetable sources --> less absorbed
72
Q
endocarditis
A
inflammation of endocardium caused by
1. infectious agents:
- s. aureus or s. viridans
2. inflammatory processes:
- rheumatic fever or SLE
3. other: metastatic cancer, carcinoid, etc
73
Q
culture negative endocarditis
A
bartonella
coxiella
mycoplasma
histoplasma
chylamydia
HACEK organisms
haemophilus, actinobacillus, cardiobacterium, eikenella, kingella
74
Q
aging heart changes
A
decrease in left ventricular chamber size (particular apex to base dimension)
- causes basal ventricular septum to bulge into left ventricular outflow tract: "sigmoid septum"

atrophy of cardiac myocytes
- increase interstitial connective tissue

progresive accumulation of brown cytoplasmic granules
- lipofuscin pigment: ingestible byproducts of subcellular membrane lipid peroxidation
75
Q
cystic fibrosis fertility
A
male infertility -- bilateral absence of vas deferens
76
Q
GI agents that slow gastric motility
A
opiates like loperamide
77
Q
loperamide
A
opiod agents that slow down gastric motility (decrease volume of diarrhea, slow intestinal transit time, increase net reabsorption)
78
Q
symptomatic rx for cystic fibrosis
A
1. n-acetylcysteine: cleaves disulfide bonds in glycoproteins of mucus
2. dornase alfa (DNAse) to clear leukocytic debris
79
Q
dornase alfa
A
DNAse for cystic fibrosis, cleave leukocytic debris
80
Q
prognosis of colorectal cancer related to
A
STAGE (spread / expansion)

not grade (differentiation)
81
Q
most impt red cell index in hereditary spherocytosis?
A
INCREASED MCHC
mean corpuscular hemoglobin concentration

- indicates membrane LOSS and red cell DEHYDRATION

(as evidence by osmotic fragility test)
82
Q
MCV in hereditary spherocytosis
A
LOW to normal, bc membrane loss
83
Q
howell-jolly bodies & pappenheimer bodies
A
associated w/ splenectomy

howell-jolly: nuclear fragments, DNA

pappenheimer bodies: iron
84
Q
eoisin-5-maleimide binding test
A
screening for hereditary spherocytosis

also see splenomegaly & increased osmotic fragility test
85
Q
Heinz bodies
A
ppt hemoglobin
- oxidation of sulfhydryl groups
86
Q
renal cell carcinoma most commonly? comes from? gross?
A
clear cell carcinoma

from PCT

golden-yellow: high glycogen and lipid content

usu has paraneoplastic (epo, acth, pthrp)
87
Q
renal oncocytomas
A
RARE tumors originating from COLLECTING DUCT cells

not clear cell!

large, well-differentiated neoplastic cells w/ numerous mitochondria

usu no paraneoplastic
88
Q
renal tumor from PCT? from collecting duct? renal pelvis?
A
PCT: clear cell carcinoma

CD: oncocytoma (rare)

pelvis: transitional cell carcinoma
89
Q
transitional cell carcinoma
A
90% of tumors involving renal pelvis.

often forms papillary tumors, composed of urothelium supported by thin fibrobvascular stalk
90
Q
prognosis of renal cell carcinoma (clear cell)
A
resistant to chemo and radiation, need to resect. if spread hematogenously already, which is common, it is bad.
91
Q
wilms tumor originates from..
A
embryonic glomerular structure.

due to loss of function mutation in WT1 or 2 on chr. 11
92
Q
beckwith-wierdman syndrome, or WAGR?
A
wilms tumor
aniridia
genitourinary malformation
mental retardation
93
Q
2. unique feature of listera monocytogenes
A
facultative intracellular, able to

1. multiply at 4 degrees (cold enrichment)
2. tumbling motility

gram positive rod (distinguish from cornybacterium)
94
Q
location of pudendal nerve block
A
S2-S4 nerve roots

1. sensory to perineum and genitals
2. motor to sphincter urethrae and external anal sphincter.

palpate intravaginally for ischial spines --> inject there
95
Q
genitofermoral nerve
A
L1-L2
- courses anterior surface of psoas muscle
- splits into genital and femoral branches
-innervates scrotum / labia majora & cutaneously femoral triangle, respectively
96
Q
iliohypogastric nerve
A
T12/L1
courses in that dermatome to innervate skin overlying iliac crests
97
Q
lateral femoral cutaneous
A
L2-L3
courses deep to inguinal ligament.
innervate skin on anterolateral thigh
98
Q
obturator n
A
L3-L4
motor innervation to medial thigh (adductor)
99
Q
inferior gluteal n
A
L5-S2
motor innervation to gluteus maximus
100
Q
krukenberg tumor
A
malignant ovarian tumor w/ mucous.

mucin-secreting signet cell adenocarcinoma

metastasis from gastric cancer / GI
101
Q
metastasis of gastric cancer can present as.. (3)
A
1. virchow node
- involvement of left supraclavicular node by metastasis from stomach

2. sister mary joseph nodule
- subcutaneous periumbilical metastasis
- (seen w/ intestinal type)

3. krukenberg tumor of ovary
- bilateral metastases to ovaries. abundant mucus signet ring cells
- (seen w/ diffuse type)
102
Q
what might decrease effectiveness of levodopa/carbidopa in parkinson's patient
A
B6 supplementation.

DOPA --> dopamine
via dopamine decarboxylase
cofactor: B6

this enzyme is blocked peripherally by carbidopa
103
Q
possible side effect of cimetidine
A
H2 receptor blocker

can cause gynecomastia!! +
104
Q
first recommendation for high LDL, high TG, and low HDL?
A
exercise and diet!!
105
Q
rx for hypertriglyceridemia (4)
A
1. diet, exercise, weight loss, abstinence from smoking & alcohol

2. fibrates (PPAR-alpha & lipoproteinlipase)

3. niacin (decreasing synthesis of TG and VLDL)

4. fish oil containing omega 3-fatty acids (decreases VLDL and triglyceridesn
106
Q
actinic keratosis
A
3-6mm scaly, erythematous lesions occuring on sun-exposed areas

histology:
-hyperkeratosis (hyperplasia of stratum corneum
-parakeratosis (retention of nuclei in stratum corneum)

pigment irregularities & dilated vessels bc associated w/ sun exposure!

small percentage progress to squamous cell carcinoma
107
Q
psoriasis presentation. location histology.
A
usu on knees and elbows and nape

hyperkeratotic plaques

histology: clubbed rete ridges, hyperkeratosis, neutrophils in stratum corneum (monroe abscesses), and perivascular lymphocytic infiltrate
108
Q
dermatofibroma
A
superficial benign fibrous histiocytoma
unknown etiology

benign proliferation of fibroblasts.
common on lower extremities as solitary nodules
109
Q
most common skin cancer
A
basal cell carcinoma
110
Q
metastasis of basal cell carcinoma? melanoma?
A
basal cell: low tendency to metastasize

melanoma: high tendency to metastazie
111
Q
presentation of basal cell carcinoma
A
usu pearly papule w/ central depression or ulceration

histology: nests of basaloid cells and peripheral palisaiding nuclei
112
Q
most common cause of renal papillary necrosis
A
diabetes mellitus
113
Q
causes of renal papillary necrosis
A
SO sAAD

- sickle cell anemia / trait
obstruction of small kidney vessels, predispose to ischemia.

- obstruction
- acute pyelo
both: edematous interstitium of pyelonephritic kidney compresses medullary vasculature --> predisposing to ischemia

- analgesic: phenacetin, acetaminophen, aspirin, caffeine, codeine
inhibit renal blood flow by decreasing prostaglandins.

- diabetic mellitus
nonenzymatic glycosylation --> alter vascular walls --> compromised renal vasculature
114
Q
abrupt onset of gross hematuria in a pt w/ family history of sickle cell suggests...
A
renal papillary necrosis
115
Q
gross & microscopic renal papillary necrosis
A
gross: gray yellow/white necrosis of tips or distal 2/3 of renal pyramids

microscopic: coagulative infarct necrosis, preserved tubule outlines. later- -> fibrous depressions
116
Q
condition that causes low complement levels
A
poststreptococcal glomerulonephritis
117
Q
thrombin time measures
A
rate of conversion of fibrinogen to fibrin

prolonged by heparin and dysfibrinogenemia
118
Q
what causes mallory-weiss tears?
A
longitudinal mucosal tears at esophagogastric-squamocolumnar junction.

secondary to rapid intraabdominal & intraluminal gastric pressures (retching & vomitting)

also: coughing, hiccuping

predisposing factor: hiatal hernias.
119
Q
evidence of steroid use
A
suspect in athlete w/ erythrocytosis, abnormal testicular size & fxn, hepatic abnormalities, & acne

1. high hematocrit (androgen stimulate RBC production)
[reason why males have higher hematocrit]

2. small testicular size, decreased sperm production, decreased endogenous testosterone

3. acne, voice deepening, male pattern baldness

hepatic side effects
120
Q
rx for hep C (chronic infection)
A
ribavarin and IFN-alpha
121
Q
ribavarin is used for..
A
chronic hep C infxn
RSV
122
Q
mechanism of ribavarin (5)
A
nucleoside antimetabolite.
interferences w/ duplication of viral genetic material

lethal hypermutation, inhibiting RNA pol and inosine monophosphate dehydrogenase (depleting GTP), causing defective 5' cap formation on mRNA transcrips, and modulates a more effective immune response.

1. phosphorylated, incorporated into RNA & pairs w. uracil or cytosine --> hypermutation during RNA dep RNA replication

2. direct inhibition of HCV RNA pol (by ribavarin triphosphate)

3. ribavarin monophosphate inhibits cellular monophosphate dehydrogenase (depleting GTP pools)
[needed to convert IMP to GMP)

4. inhibits viral RNA guanylyltransferase and methytransferase, resulting in defective 5' cap formation on mRNA --> ineffective translation

5. enhances Th1-cell mediated immunity while inhibiting Th2 cytokine production --> modulates a more effective immune response
123
Q
which two drugs block IMP dehydrogenase? what step is blocked
A
purine de novo synthesis

IMP -> GMP

mycophenolate & ribavarin