Block 2 Flashcards
What is the equation for Vd?
Vd = (amount of drug given)/(plasma concentration of drug)
What are the averages for total body water, extracellular fluid, and plasma volume?
average total body water: 41 L
extracellular fluid: 14 L
plasma: 3 L
What properties contribute to a low volume of distribution?
low Vd: high molecular weight, high polarity, high binding to plasma proteins
drugs that have low molecular weight and are uncharged can cross cell membranes and reach intracellular compartments, so they have a high Vd
What is the typical timing for a positive B-hCG result in the urine?
in the serum?
urine: 14 days after ovulation
serum: 8 days after oovulation
on which day does the multicellular morula enter the uterus as a 2-8 celled embryo?
3-4 days post ovulation
how long after fertilization does implantation occur?
6-12 days
when is the first dose of the Hib vaccine given?
at 2 months of age
before 2 months, humoral immunity is received from maternal IgG
what is the capsule of H influenzae composed of?
polyribosyl-ribitol-phosphate (PRP)
antiboodies to PRP facilitate complement-dependent phagocytosis and killing through opsonization
What do you see in Von Hippel-Lindau?
autosomal dominant, chromosome 3p deletion
- cerebellar hemangioblastomas
- clear cell renal carcinomas
- pheochromocytomas
What are the 3 causes of Down Syndrome?
trisomy 21 (95%)
unbalanced Robertsonian translocations (extra arm of chr 21): 2-3%
mosaicism (pts have 2 cell lines: 1 normal, 1 w/ trisomy 21)
which drugs have been clearly shown to slow the progression of diabetic neuropathy in Type 1 and Type 2 diabetes both prior and after proteinuria?
ACE inhibitors, ARBs
what brain changes do you see in Huntington disease?
bilateral atrophy of the caudate nucleus and putamen (which form the striatum)
caudate atrophy leads to typical dilation of the frontal horns of the lateral ventricles
loss of GABA-containing neurons leads to decreased GABA
where are the leads placed in a 3-lead pacemaker?
the first 2 leads are placed in the right atrium and right ventricle
the 3rd lead paces the left ventricle
the lead enters the right atrium –> coronary sinus (which resides in the atrioventricular groove on the posterior aspect of the heart) –> lateral venous tributary
what is the reason that gram-positive organism are now a more frequent cause of nosocomial bloodstream infections?
increasing use of intravascular devices shifting the microbiology
what drug is used in patients who have had a transient ischemic attack to prevent primary and secondary coronary artery events/strokes
low dose aspirin
what is specificity?
(number of true negatives)/(total number of patients without disease)
what is sensitivity?
(number of true positives)/(total number of pts with disease)
how to calculate false positives?
(1-specificity)*number of patients without disease
S4 heart sound
sign of diastolic dysfunction, occurs when there is a sudden rise in the end-diastolic ventricular pressure caused by atrial contraction against a ventricle that has reached its elastic limit (aortic stenosis, hypertrophic cardiomyopathy)
what is the biggest cause of wrinkles?
decrease in collagen fibril production, decreased dermal collagen and elastic fibers –> sagging, wrinkles
what disease shows proximal muscle weakness, increased CK, increased anti-Jo, CD8+ T cells
polymyositis
what lung cancers are associated with smoking?
squamous cell carcinoma, small cell carcinoma
most common lung cancer?
adenocarcinoma, frequently in women/nonsmokers
how can small cell carcinomas be distinguished from non small cell carcinomas?
small cell is distinguished by its aggressive behavior and is treated with chemo and radiation
nonsmall cell carcinomas can be treated w/ surgery if localized
What does a negative Gibbs free energy number mean?
G = -RT(ln Keq)
If Gibbs is negative, Keq will be greater than 1, meaning the concentration of products will exceed that of substrates
what happens to atropines half life in the elderly?
atropine’s half-life may be prolonged from its usual 3 hours to up to 10-30 hrs due to decreased clearance –> toxicity
what is coarctation of the aorta associated with?
other cardiac anomalies or with berry aneurysms of the Circle of Willis
these berry aneurysms are prone to rupture. Coarctation of the aorta –> increased hypertension in the brances of the aortic arch proximal to coarct –> subarachnoid hemorrhage
Which component of HIV binds to CD4 and CCR5 chemokine receptors, leading to HIV entry from fusion with the cell membrane?
HIV viral outer envelope protein gp120
If cells don’t express CCR5 on membrane, HIV binds to CD4 but is unable to enter the cell
What are Nef and Tat?
Nef and Tat are HIV genes
TAT gene product plays a role in viral replication
Nef decreases expression of MHC class I proteins on the surfaces of infected cells
What cells of the adrenal medulla receive sympathetic input and are stimulated by ACh released by preganglionic neurons to secrete NE and Epinephrine directly into the blood stream (80% epi, 20% NE)?
chromaffin cells
What can be a limiting factor when initiating ACE inhibitors and what other drugs can potentiate that factor?
first dose hypotension
thiazide loop diuretics can cause hypovolemia and hyponatremia, thus potentiating the effects of 1st dose hypotension
which “swish and swallow” agent binds to ergosterol molecules in the fungal cell membrane, causing pores and leakage of fungal cell contents?
given as an oral agent to treat thrush
nystatin
what are asthma patients who take oral or inhaled steroids at risk for?
candidiasis
why are ritodrine and terbutaline used to defer premature labor?
they are B2 agonists
adrenergic receptors of the uterus belong to the B2 group whose stimulate leads to uterine RELAXATION
Winter’s formula
PaCO2 = 1.5 * HCO3- + 8 (+/-)2
What is unique about S. bovis in addition to its association with colonic malignancy?
Causes endocarditis but the majority of cases are in patients with no preexisting valvular abnormality
Caucasian boy brought to clinic because face is “puffy” in morning and he has proteinuria
Minimal change disease
What happens when Ca2+ binds to troponin C?
tropomyosin shifts to expose the actin binding sites for myosin, allowing contraction to occur
what is the gold standard for diagnosis of mesothelioma?
electron microscopy
EM will show tumor cells with numerous, long, slender microvilli and abundant tonofilaments
adenocarcinoma have short, plump microvilli
in what disease will an EM show tumor cells with numerous, long, slender microvilli and abundant tonofilaments?
electron microscopy
what is the triad seen in fat embolism syndrome?
acute onset neurologic symptoms
hypoxemia
petechial rash
how does a fat embolism cause ARDS?
fat globules occlude microvessels in lung –> release of fatty acids from globules causes local toxic injury to endothelium –> ARDS
why do fat embolisms causes thrombocytopenia and petechiae?
platelets adhere to and coat the fat microglobules
how do fat emboli cause acute onset neurologic symptoms?
some fat globules escape lungs and occlusion can happen in the CNS
what does hypothermia due to the oxygen hemoglobin saturation curve?
shifts curve to the left
lower temperatures help to stabilize the bonds between oxygen and hemoglobin
