Random USMLE Facts volume 1-5

Rahul's Noteblog Notes on USMLE facts, Exam Tips, and USMLE Lab Values Random USMLE Facts volume 1-5

Random USMLE Facts volume 1-5:

USMLE Facts 1	USMLE Facts 2	USMLE Facts 3	USMLE Facts 4	USMLE Facts 5
USMLE Facts 6	USMLE Facts 7	USMLE Facts 8	USMLE Facts 9	USMLE Facts 10

What is the function of snRNP?

Intron removal from RNA transcript, thus used to synthesize mRNA. snRNPs are spliceosomes.

What is the function of aminoacyl-tRNA synthetases?

Catalyze linkage of tRNAs to corresponding amino acids.

Findings in Potter Syndrome?

Infants with severe respiratory distress syndrome, hypoplastic lungs, and absent kidneys.

What chemotactic agent stimulates neutrophil migration to the site of inflammation?

LTB4, 5-HETE, and C5a.

Function of bradykinin?

Vasodilatation, increased vascular permeability, smooth muscle contraction, and pain.

What are the functions of thiamine? What happens during thiamine deficiency?

Thiamine is a cofactor for these enzymes: pyruvate dehydrogenase, alpha-ketoglutarate dehydrogenase, branched-chain amino acid dehydrogenase, and transketolase.

During thiamine deficiency, there is decreased glucose utilization, especially in the central nervous system (necrosis of mamillary bodies and gray matter surrounding the third and fourth ventricles).

What blood vessel has the highest oxygen content in fetal circulation?

Umbilical vein, followed by the interior vena cava.

What reaction in the TCA cycle is inhibited during alcohol intoxication?

Conversion of alpha-ketoglutarate to succinyl CoA.

What are the consequences of carnitine deficiency?

Impairment of fatty acid transportation into mitochondria, and decreased ketone body production (eg., decreased production of acetoacetate).

Why does acyclovir demonstrate decreased activity against EBV and CMV, but increased activity against HSV-1, HSV-2, and VZV?

Because HSV-1, HSV-2, and VZV produce a virally-encoded thymidine kinase that immediately converts acyclovir into active acyclovir monophosphate. Thus, HSV-1, HSV-2, and VZV increase acyclovir phosphorylation rate.

What is a noninvasive treatment for paroxysmal supraventricular tachycardia?

Vagal stimulation such as carotid massage or the Valsalva maneuver.

During small bowel obstruction, where is the offending agent most likely stuck in?

Ileum (blocking the ileocecal valve)

What is the concept of 'aldosterone escape?'

Hyperaldosteronism is produced by tumors, and high levels of aldosterone are secreted by the zona glomerulosa. Increased aldosterone secretion causes sodium retention, hypertension, metabolic alkalosis, and hypokalemia. However, hypernatremia rarely occurs due to a concept called 'aldosterone escape.' The two following processes occur during 'aldosterone escape':

1. While it is true that increased aldosterone causes sodium retention, extreme increase in aldosterone actually causes excretion of sodium.

2. With so much sodium in the body, ANP is also released from the atria.

Thus, these two processes cause excretion of sodium.

What is lead-time bias?

Patients who are diagnosed with the disease earlier tend to live longer.

Consumption of what type of food causes infection by enterohemorrhagic e. coli?

Undercooked beef or contaminated ground beef. Most infections are caused by the EHEC O157:H7 strain.

How is glucose transported into a cell?

Facilitated diffusion; from area of higher concentration to area of lower concentration.

USMLE Facts 1	USMLE Facts 2	USMLE Facts 3	USMLE Facts 4	USMLE Facts 5
USMLE Facts 6	USMLE Facts 7	USMLE Facts 8	USMLE Facts 9	USMLE Facts 10

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