test #36 4.27 Flashcards
4 A’s of Ataxia-telengectiasia
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
bare lymphocyte syndrome
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
how does cisplatin exert chemotherapeutic effects? how can this be prevented (2 ways)
generates reactive oxygen species that can cross-link DNA
- amifostine = free radical scavenger. can prevent nephrotoxity and acoustic nerve damage.
- establishing chloride diuresis (IV normal saline) bc cisplatin stays in nonreactive state when in high Cl- concentration
N-acetylcysteine for influenza, bronchitis, cystic fibrosis?
mucolytic agent
-cleaves DISULFIDE bones in mucous glycoproteins
also
- enhances glutathione production
- conjugates NAPQI
- prevents radiocontrast-induced nephropathy
4 main effects
filgrastim
G-CSF analong.
stimulate prolif and diff of granulocytes
fomepizole
antidote in methanol (rubbing alcohol) or ethylene glycol (antifreeze) posioning
competitive antagonist of alcohol dehydrogenase (prevents conversion into toxic metabolites)
methanol is in..
rubbing alcohol
ethylene glycol is in…
antifreeze
dexrazoxane
iron-chelating agent, help prevents anthracycline-induced (doxorubicin) toxicity
CHF
anthracycline fxn
generate free radicals –> intercalate DNA –> cause breaks
antitumor antibiotic
congenital hypothyroidism (cretinism)
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
what can cause congenital hypothyroidism (4)
- maternal hypothyroidism,
- thyroid agenesis,
- thyriod dysgenesis (most common in US
- dyshormonogenic goiter
4 general effects of thyroid hormones
4 B’s
- brain maturation
- bone growth (increased osteoclast activity
- b-adrenergic (upregulate B1 in heart)
- increased BMR
phenothiazine
antipsychotic / antihistamine
block D2 receptor –> relieves inhibition –> cause hyperprolactinemia at certain doses
how does dopamine inhibit prolactin secretion?
binds to D2 receptor on prolactin-producing cells
competence defined as..
ability to understand a situation and the possible CONSEQUENCES of decisions made in a situation
who makes medical decisions if there is no next of kin?
judge / court will appoint a guardian to act on the patient’s behalf
[hospital ethics committee makes recommendations, but cannot act]
describe how sunlight increases vitamin D
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)
how is excess 1,25-vitamin D dealt w/
kidney has enzyme 24 hydroxylase, converts 25 hydroxy-vitamin D to inactive 24,25 dihydrox vitamin D
vitamin D2. vitamin D3. cholecalciferol. calcidiol. calcitriol. 24,25-dihydrocholecalciferol
- vitamin D2: plant-derived
- vitamin D3: cholecalciferol; physiologically produced
- calcidiol: 25-hydroxy vitamin D
- calcitriol: 1,25-dihydroxy vitamin D
precision and reliability
essentially equivalent. low variability when measuring same thing.
PCA territory? symptoms expected?
- 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
ACA covers..
- frontal: inferior and medial
- parietal: medial
- anterior 4/5 of corpus callosum
- olfactory bulb and tract
- anterior basal ganglia (caudate)
- anterior limb internal capsule
anterior choroidal
last branch off internal carotid before it trifurcates.
supplies posterior limb of internal capsule, optic tract, LGN, choroid plexus, uncus, hippocampus, amygdala
artery of percheron
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
MCA covers
- lateral convexity of frontal, parietal, temporal lobe
- deep subcortical structures, like internal capsule, basal ganglia.
usu contralateral motor & sensory defects
exogenous cortisol suppresses what part of HPA axis?
all! CRH, ACTH, and cortisol
bilateral adrenal cortical atrophy
unilateral of adrenal cortex can result from..
adrenocortical adenoma
autonomous production of cortisol from one adrenal gland suppresses CRH, ACTH. less stimulation of the OTHER gland.
triggers for atopic dermatitis? presentation in young children? older children
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)
cause of atopic dermatitis
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:
- high serum levels of IgE,
- peripheral eosinophilia,
- high cAMP phosphodiesterase in leukocytes
allergic triad
allergic rhinitis
asthma
atopic dermatitis
gluten enteropathy & dermatitis herpetiformis presentation
usually in 4th-5th decades of life. UNCOMMON in children!
pruritic vesicles & plaques on buttocks & extensor surfaces.
erythematous, well-demarcated papules and plaques w/ silvery scale
psoriasis
dermatitis herpetiformis vs. atopic dermatitis
atopic dermatitis: usu kids
dermatitis herpetiformis: usu presents in 4th-5th decade of life, uncommon in kids.
acute viral hepatitis on hepatocyte (2)
- hepatocyte injury
2. hepatocyte death
travel to foreign country (overcrowing & poor sanitation) & return w/ liver problems
think acute hepatitis A
hepatocyte injury vs. hepatocyte death
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
bridging necrosis
regions of adjacent lobules are interconnected by swatches of dead hepatocytes
presentation of viral A hepatitis
acute.
fever, malaise, fatigue, anorexia, nausea & vomiting, mild abdominal pain.
DARK URINE = increase serum bilirubin.
hepatomegaly & jaundice
prolonged pruritus and fatigue suggests
primary sclerosing cholangitis (diffuse inflammation and fibrosis of biliary tract)
recall pruitus – bile acid mediated
acholic stools and bone pain suggests
chronic cholestatis process, like primary biliary cirrhosis
liver lobule
functional anatomical unit of liver.
hexagonal structure centered on central vein
portal triad at each corner
liver acinus
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
acute hepatitis primary affects what part of liver? chronic?
acute: lobule & portal tract
chronic: predominantly portal tract
formula for resistance
R = nL / r^4
n = viscosity L = length r = radius
facies of potter syndrome
suborbital creases
depressed nasal tip
low set eats
retrognathia
common intraabdominal infections (i.e. post perforated appendix)
usu polymicrobial:
- b. frag
- ecoli
most common
candida can be isolated from an intraabdominal infection related to.
perforation of proximal bowel, like perforated peptic ulcer
what does EBV bind to in order to enter cell?
CD21 on B-lymphocytes
EBV glycoprotein gp350 binds to C3d complement component receptor CD21
where is CD21 expressed
- B cell surface
2. nasopharyngeal epithelial cells
how does parvovirus enter erythroid cells
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)
how does CMV bind to cells
like other herpesvirus, via glycosaminoglycans
how does adenovirus enter cells
rodlike structures from its penton base capsomeres mediate adsorption to host cells.
receptor: transmembrane protein member of immunoglobulin superfamily
kozack sequence
on mRNA
initiator for translation
gcc(A or G)ccAUGG
purine 3 bases upstream AUG = very important
shrine dalgarno
8bp upstream AUG
help recruit ribosome to mRNA
3 steps of translation (note where energy is used)
- initiation (IF, uses GTP)
- assemble 40s subunit w/ initiator tRNA. wait for mRNA & 60s to bind - 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) - termination, stop codon – recognized by release factor. polypeptide released
what are the three end products of the nonoxidative (reversible) part of HMP shunt
- ribose 5-phosphate
- glyceraldehyde 3-phosphate
- fructose 6-phoshate
NADPH vs. NADH
NADPH used as reducing equivalent in cytosol
NADH used as energy source for ATP synthesis (electron transport chain)
how can ribose be synthesized by fructose-6-phosphate or glyceraldehyde-3-phosphate
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
what reaction do transketolase do? transaldolase?
transketolase: transfers 2 carbon groups
transaldolase: transfers 3 carbon groups
which cells produce NADPH (3 main uses)
- NADPH consumed in fatty acid & steroid synthesis.
- cytochrome p450 pathway
- generation of superoxide in phagocytes
so liver, adrenal cortex, gonads, adipose tissue, erythrocytes
making MPO in phagocytes
- NADPH oxidase (O2-> superoxide
- superoxide dismutase (superoxide -> hydrogen peroxide
- myeloperoxidase (hydrogen peroxide -> MPO)
enolase
converts 2-phosphoglycerate -> phosphoenolpyruvate in glycolysis
aconitase
citrate -> isocitrate in TCA
green pigment in echhymoses
biliverdin
heme -> biliverdin
via HEME OXYGENASE
continuous leuprolide on testosterone and DHT levels
concordant transient increase, followed by decrease in both
B12 + R protein? B-12 + intrinsic factor
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
r protein
haptocorrin – made in salvia
-binds B12, protects from stomach acid
degraded by pancreatic enzymes
most cases of B12 deficiency
unrelated to intake.. usu poor absorption.
b12 often needs to be taken parenterally
elderly patient w/ chronic anemia and unknown underlying cause?
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
in what form is diet more readily absorpbed
dietary meat: iron in heme form –> more readily absorbed
iron from vegetable sources –> less absorbed
endocarditis
inflammation of endocardium caused by
- infectious agents:
- s. aureus or s. viridans - inflammatory processes:
- rheumatic fever or SLE - other: metastatic cancer, carcinoid, etc
culture negative endocarditis
bartonella coxiella mycoplasma histoplasma chylamydia HACEK organisms haemophilus, actinobacillus, cardiobacterium, eikenella, kingella
aging heart changes
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
cystic fibrosis fertility
male infertility – bilateral absence of vas deferens
GI agents that slow gastric motility
opiates like loperamide
loperamide
opiod agents that slow down gastric motility (decrease volume of diarrhea, slow intestinal transit time, increase net reabsorption)
symptomatic rx for cystic fibrosis
- n-acetylcysteine: cleaves disulfide bonds in glycoproteins of mucus
- dornase alfa (DNAse) to clear leukocytic debris
dornase alfa
DNAse for cystic fibrosis, cleave leukocytic debris
prognosis of colorectal cancer related to
STAGE (spread / expansion)
not grade (differentiation)
most impt red cell index in hereditary spherocytosis?
INCREASED MCHC
mean corpuscular hemoglobin concentration
- indicates membrane LOSS and red cell DEHYDRATION
(as evidence by osmotic fragility test)
MCV in hereditary spherocytosis
LOW to normal, bc membrane loss
howell-jolly bodies & pappenheimer bodies
associated w/ splenectomy
howell-jolly: nuclear fragments, DNA
pappenheimer bodies: iron
eoisin-5-maleimide binding test
screening for hereditary spherocytosis
also see splenomegaly & increased osmotic fragility test
Heinz bodies
ppt hemoglobin
- oxidation of sulfhydryl groups
renal cell carcinoma most commonly? comes from? gross?
clear cell carcinoma
from PCT
golden-yellow: high glycogen and lipid content
usu has paraneoplastic (epo, acth, pthrp)
renal oncocytomas
RARE tumors originating from COLLECTING DUCT cells
not clear cell!
large, well-differentiated neoplastic cells w/ numerous mitochondria
usu no paraneoplastic
renal tumor from PCT? from collecting duct? renal pelvis?
PCT: clear cell carcinoma
CD: oncocytoma (rare)
pelvis: transitional cell carcinoma
transitional cell carcinoma
90% of tumors involving renal pelvis.
often forms papillary tumors, composed of urothelium supported by thin fibrobvascular stalk
prognosis of renal cell carcinoma (clear cell)
resistant to chemo and radiation, need to resect. if spread hematogenously already, which is common, it is bad.
wilms tumor originates from..
embryonic glomerular structure.
due to loss of function mutation in WT1 or 2 on chr. 11
beckwith-wierdman syndrome, or WAGR?
wilms tumor
aniridia
genitourinary malformation
mental retardation
- unique feature of listera monocytogenes
facultative intracellular, able to
- multiply at 4 degrees (cold enrichment)
- tumbling motility
gram positive rod (distinguish from cornybacterium)
location of pudendal nerve block
S2-S4 nerve roots
- sensory to perineum and genitals
- motor to sphincter urethrae and external anal sphincter.
palpate intravaginally for ischial spines –> inject there
genitofermoral nerve
L1-L2
- courses anterior surface of psoas muscle
- splits into genital and femoral branches
- innervates scrotum / labia majora & cutaneously femoral triangle, respectively
iliohypogastric nerve
T12/L1
courses in that dermatome to innervate skin overlying iliac crests
lateral femoral cutaneous
L2-L3
courses deep to inguinal ligament.
innervate skin on anterolateral thigh
obturator n
L3-L4
motor innervation to medial thigh (adductor)
inferior gluteal n
L5-S2
motor innervation to gluteus maximus
krukenberg tumor
malignant ovarian tumor w/ mucous.
mucin-secreting signet cell adenocarcinoma
metastasis from gastric cancer / GI
metastasis of gastric cancer can present as.. (3)
- virchow node
- involvement of left supraclavicular node by metastasis from stomach - sister mary joseph nodule
- subcutaneous periumbilical metastasis
- (seen w/ intestinal type) - krukenberg tumor of ovary
- bilateral metastases to ovaries. abundant mucus signet ring cells
- (seen w/ diffuse type)
what might decrease effectiveness of levodopa/carbidopa in parkinson’s patient
B6 supplementation.
DOPA –> dopamine
via dopamine decarboxylase
cofactor: B6
this enzyme is blocked peripherally by carbidopa
possible side effect of cimetidine
H2 receptor blocker
can cause gynecomastia!! +
first recommendation for high LDL, high TG, and low HDL?
exercise and diet!!
rx for hypertriglyceridemia (4)
- diet, exercise, weight loss, abstinence from smoking & alcohol
- fibrates (PPAR-alpha & lipoproteinlipase)
- niacin (decreasing synthesis of TG and VLDL)
- fish oil containing omega 3-fatty acids (decreases VLDL and triglyceridesn
actinic keratosis
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
psoriasis presentation. location histology.
usu on knees and elbows and nape
hyperkeratotic plaques
histology: clubbed rete ridges, hyperkeratosis, neutrophils in stratum corneum (monroe abscesses), and perivascular lymphocytic infiltrate
dermatofibroma
superficial benign fibrous histiocytoma
unknown etiology
benign proliferation of fibroblasts.
common on lower extremities as solitary nodules
most common skin cancer
basal cell carcinoma
metastasis of basal cell carcinoma? melanoma?
basal cell: low tendency to metastasize
melanoma: high tendency to metastazie
presentation of basal cell carcinoma
usu pearly papule w/ central depression or ulceration
histology: nests of basaloid cells and peripheral palisaiding nuclei
most common cause of renal papillary necrosis
diabetes mellitus
causes of renal papillary necrosis
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
abrupt onset of gross hematuria in a pt w/ family history of sickle cell suggests…
renal papillary necrosis
gross & microscopic renal papillary necrosis
gross: gray yellow/white necrosis of tips or distal 2/3 of renal pyramids
microscopic: coagulative infarct necrosis, preserved tubule outlines. later- -> fibrous depressions
condition that causes low complement levels
poststreptococcal glomerulonephritis
thrombin time measures
rate of conversion of fibrinogen to fibrin
prolonged by heparin and dysfibrinogenemia
what causes mallory-weiss tears?
longitudinal mucosal tears at esophagogastric-squamocolumnar junction.
secondary to rapid intraabdominal & intraluminal gastric pressures (retching & vomitting)
also: coughing, hiccuping
predisposing factor: hiatal hernias.
evidence of steroid use
suspect in athlete w/ erythrocytosis, abnormal testicular size & fxn, hepatic abnormalities, & acne
- high hematocrit (androgen stimulate RBC production)
[reason why males have higher hematocrit] - small testicular size, decreased sperm production, decreased endogenous testosterone
- acne, voice deepening, male pattern baldness
hepatic side effects
rx for hep C (chronic infection)
ribavarin and IFN-alpha
ribavarin is used for..
chronic hep C infxn
RSV
mechanism of ribavarin (5)
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.
- phosphorylated, incorporated into RNA & pairs w. uracil or cytosine –> hypermutation during RNA dep RNA replication
- direct inhibition of HCV RNA pol (by ribavarin triphosphate)
- ribavarin monophosphate inhibits cellular monophosphate dehydrogenase (depleting GTP pools)
[needed to convert IMP to GMP) - inhibits viral RNA guanylyltransferase and methytransferase, resulting in defective 5’ cap formation on mRNA –> ineffective translation
- enhances Th1-cell mediated immunity while inhibiting Th2 cytokine production –> modulates a more effective immune response
which two drugs block IMP dehydrogenase? what step is blocked
purine de novo synthesis
IMP -> GMP
mycophenolate & ribavarin
