Flashcards in test #36 4.27 Deck (123)
4 A's of Ataxia-telengectiasia
B & T cell immunodeficiency
- 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
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
N-acetylcysteine for influenza, bronchitis, cystic fibrosis?
-cleaves DISULFIDE bones in mucous glycoproteins
-enhances glutathione production
-prevents radiocontrast-induced nephropathy
4 main effects
stimulate prolif and diff of granulocytes
antidote in methanol (rubbing alcohol) or ethylene glycol (antifreeze) posioning
competitive antagonist of alcohol dehydrogenase (prevents conversion into toxic metabolites)
methanol is in..
ethylene glycol is in...
iron-chelating agent, help prevents anthracycline-induced (doxorubicin) toxicity
generate free radicals --> intercalate DNA --> cause breaks
congenital hypothyroidism (cretinism)
- 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)
-thyriod dysgenesis (most common in US
- dyshormonogenic goiter
4 general effects of thyroid hormones
1. brain maturation
2. bone growth (increased osteoclast activity
3. b-adrenergic (upregulate B1 in heart)
4. increased BMR
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)
-medial temporal lobe
- splenium of corpus callosum
- parahippocampal gyrus
- fusiform gyrus
- occipital lobe
-frontal: inferior and medial
- anterior 4/5 of corpus callosum
- olfactory bulb and tract
- anterior basal ganglia (caudate)
- anterior limb internal capsule
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
- 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..
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)
- FOOD, irritants
usu present by 5 y/o:
red, weeping/crusted lesions involving face, scalp, extensor surfaces. diaper area usu spared.
manifests as lichenification in flexural distribution (neck, wrists, antecubital, popliteal fossa)