Mixed 4 Flashcards
What is Attributable risk percent in exposed?
ARP measures the impact of a risk factor. it represents the excess risk in an exposed population that can be explained by exposure to a particular risk factor.
[Ex. What percentage of an outcome (SCC of esophagus) can be attributed to a particular risk factor (smoking)?]
What is Nondisjunction? Give an example.
Failure of chromosome pairs to separate properly during cell division. This could be due to failure of homologous chromosomes to separate in meiosis I or failure of sister chromatids to separate during meiosis II or mitosis. Down syndrome (trisomy 21) often arises due to nondisjunction during maternal meiosis I.
How would a child with lead toxicity present?
This is likely a poor child living in old urban housing w/ chipped paint. Lead can cause neurotoxic ssx as a long-term complication due to the incomplete BBB in kids. The child will also have anemia. Labs show inc. protoporphyrin and inc. ALA levels.
What is the MOA of opiates on spinal cord neurons to induce analgesia?
Opioids activate presynaptic mu-receptors on the afferent neuron, causing closure of voltage-gated Ca channels and dec. excitatory neurotransmission. They also bind to postsynaptic mu-receptors, opening K channels and causing hyperpolarization via K efflux.
How does the blood-brain barrier permit passage of solutes?
The BBB is formed by tight junctions b/w nonfenestrated endothelial cells that prevent paracellular passage. Passage is only allowed via transcellular movement, w/c is limited by diffusion or carrier-mediated transport.
>Since dopamine lacks transport carriers, it can’t cross the BBB, vs. L-DOPA that has affinity for neutral amino acid transporter.
What’s the pathogenesis of M3 AML subtype?
t(15;17) is a translocation involving retinoic acid receptor alpha (RARA) from chromosome 17 and the promyelocytic leukemia (PML) gene on chromosome 15. This leads to fusion gene PML/RARA that codes fro abnormal retinoic acid receptor. This abnormal protein inhibits myeloblast differentiation.
What would the peripheral blood smear of a patient w/ AML look like?
Inc. circulating myeloblasts, promyelocytes, and Auer rods.
Anemia, Thrombocytopenia, Neutropenia.
What determines the murmur intensity in hypertrophic cardiomyopathy?
The degree of LVOT obstruction (murmur intensity) is based on LV end-diastolic volume. Maneuvers that INCREASE preload or afterload will DECREASE murmur intensity by inc. LV-EDV and lessening LVOT obstruction.
>Squatting, passive leg raise, sustained hand grip.
When treating a patient for alcohol withdrawal, which benzodiazepines do you give them if they show a history of liver disease?
In pts w/ liver dse going through alcohol withdrawal, BZDs that don’t undergo oxidative metabolism in the liver and have no active metabolites are preferred (Lorazepam, Oxazepam, Temazepam).
>BZDs w/ active metabolites include diazepam and chlordiazepoxide.
What electrolyte imbalance can be caused during thyroid surgery?
Hypocalcemia can be caused due to injury to parathyroid glands during thyroid surgery – primary hypoparathyroidism, hypocalcemia.
What does Romberg test used to determine?
Romberg test is a test of proprioception used to distinguish sensory ataxia from cerebellar ataxia. Pts stand w/ feet together, arms at sides, and eyes closed. Failure to maintain posture indicates sensory ataxia.
How does the endometrium appear in proliferative phase and secretory phase of the menstrual cycle?
> Proliferative: estrogen stimulation; endometrial proliferation and thickening, spiral arteries in deeper layers, straight uterine glands, no secretions.
Secretory: progesterone; coiled uterine glands w/ mucus secretion, edematous endometrial stroma, spiral arteries reaching surface.
What is the MOA of benzodiazepines? What are their effects?
> Inc. frequency of opening the CNS GABA-A receptor-chloride channels – inc. Cl- permeability hyperpolarizes membrane – less excitable neuron.
Anxiolytic, anticonvulsant, muscle relaxant, sedative-hypnotic.
What are the 3 meds for pregnancy termination (3 M’s)? Their effects?
> Misoprostol: PGE1 agonist – cervical softening, uterine contractions.
Mifepristone: Progesterone antagonist, glucocorticoid antagonist – necrosis of uterine decidua.
Methotrexate: folic acid antagonist – inhibits trophoblast division, hinders implantation.
What mutation is involved in the chronic myeloproliferative disorders?
W/ the exception of CML, the chronic myeloproliferative disorders often have JAK2 mutation. This results in constant tyrosine kinase activity and activation of STAT proteins. The activated STAT translocates to the nucleus and promotes transcription (ex. polycythemia vera).
