April 20 Flashcards Preview

1 UWorld > April 20 > Flashcards

Flashcards in April 20 Deck (54)
Loading flashcards...

What type of cardiotoxicity is caused by doxorubicin (-rubicins)?

Dilated cardiomyopathy
--caused by generation of free radicals


What immune cascade is responsible for toxic shock syndrome?

Toxic shock syndrome toxin--S. aureus or Exotoxin A--S. pyogenes---binds to MHC II and TCR (activation of macrophages and T-lymphocytes) outside of antigen binding site to cause overwhelming release of IL-1, IL-2, IFN-g and TNF-a---> Shock


A process by which a single gene can code for various unique proteins by selectively including or excluding different DNA coding regions (exons) into mature mRNA?

Alternative splicing


Potency of an inhaled anesthetic is inversely proportional to...

MAC--Minimal Alveolar Concentration---required to prevent 50% of subjects from moving in response to noxious stimulus

Lower the MAC= higher potency


Thyroid peroxidase is responsible for...

oxidation of iodide to iodine
iodination of thyroglobulin tyrosine residues
iodotyrosine coupling reaction that forms T3 and T4

Pg 315


Stress incontinence is defined as involuntary urine loss with increased intraabdominal pressure---kegel exercises target what structure to help with this problem?

Levator ani--improves support around urethra and bladder


What must occur in order for Hep D to cause infection?

Hep B surface antigen must coat the Hep D antigen before it can infect hepatocytes and multiply


What is the most abundant amino acid within collagen?

Glycine--helical conformation--> simple and repetetive amino acid sequence within each alpha chain where glycine occupies every third amino acid position


What is the MOA of methimazole used in hyperthyroidism?

Block thyroid peroxidase--inhibiting the oxidation of iodide and the organification (coupling) of iodine

PTU--same MOA, BUT also blocks 5' deiodinase--> decreasing peripheral conversion of T4--> T3


Activation of RAS proteins is caused by binding of what?


Binding of GDP--inactive

Mutations cause constant activation--malignant tumors


What is seen on light microscopy of pt with Guillian-Barre?

Segmental demyelination of peripheral nerves and and endoneural inflammatory infiltrate


2 y/o boy presents with fever sleepiness, vomiting. Labs show elevated ammonia, increased orotic acid in blood and urine, and decreased BUN. Dx?

Ornithine transcarbamylase deficiency


_______ are primarily responsible for sensing arterial PaO2 and can be suppressed with oxygen administration.

Peripheral chemoreceptors --carotid and aortic bodies


Pts with CF loss what in their sweat, which can lead to what?

Cl- and Na- leading to hypovolemia caused by intravascular volume contraction


Prolonged exposure to load noises leads to hearing loss due to damage to what?

Stereociliated hair cells of the organ of Corti
--High-frequency hearing loss occurs first


What is the MOA of entacapone and tolcapone used with Parkinson disease?

Prevent peripheral L-dopa degradation to 3-O-methyldopa (3-OMD) by inhibiting COMT --increasing levodopa bioavailability to the brain


What is the mechanism of action of ethosuximide used for tx of absence seizures?

Blocks thalamic T-type Ca2+ channels


What is typically the first symptom of ETOH withdrawal?


Delirium tremens --- most severe manifestation and typically begins 48-96hrs after last drink --chlordiazepoxide


Histopathology of chronic hashimoto thyroditis shows what?

Intense lymphocytic infiltrate, often with germinal centers
Residual follicles are often surrounded by Hurthle cells--large oxyphillic cells filled with granular cytoplasm


Essential fructosuria is a benign condition caused by deficiency in _______ and fructose can still be metabolized to Fructose-6-phosphate by_____.



Hereditary fructose intolerance is caused by a deficiency in _____, which presents with failure to thrive, liver and renal failure, hypoglycemia and vomiting after fructose ingestion.

Aldolase B deficiency


Formation of atheroma is mediated by what?

Release of PDGF by locally adherent platelets, endothelial cells, and macrophages
--promoting migration of smooth muscle cells from the media into the intima and subsequent proliferation


Pts with sleep apnea can have increased HCT, which is caused by what?

Renal cortical cells sensing hypoxia and respond by synthesizing and releasing EPO, which stimulates the production of erythrocytes in the bone marrow


Hydroceles and ______ inguinal hernias in an infant are caused by failure of processes vaginalis to close.



Which monosaccharide is metabolized the fastest by the liver and why?

Fructose--only one that bypasses phosphofructokinase --one of the key enzymes involved in regulating glycolysis


FNA of thyroid shows large cells with overlapping nuclei containing finely dispersed chromatin and intranuclear inclusions and grooves. Dx?

Papillary carcinoma
--Orphan Annie eyes
--Psammoma bodies
--Nuclear grooves


Superior sulcus tumor is also known as?

Pancoast lung tumor located in the lung apex
--causes referred shoulder pain, ipsilateral horners, and spinal cord compression


Pyruvate can take 2 separate pathways depending on availability of O2. If O2 is present then pyruvate is converted to ______ by ______. If O2 is absent then pyruvate is converted to ______ by ______.

Acetyl-CoA by pyruvate dehydrogenase--Aerobic

Lactic acid by lactate dehydrogenase--Anaerobic
--Can lead to lactic acidosis


Pts receiving blood transfusion that is greater than body blood volume (5-6L) can develop what, which is caused by what?

Hypocalcemia caused by elevated citrate levels, which is added to blood products
--The citrate chelates Ca2+ causing symptoms of hypocalcemia and hypomagnesium --causing paresthesia


What are the symptoms of stimulant (cocaine, amphetamine) withdrawal?

Increased appetite
Intense psychomotor retardation
Severe depression-"Crash"
--acute depression with vivid dreams