Uworld: 4B

Front 1

Describe the synthesis of estrogen by oocytes.

Begin with LH.

Back 1

Front 2

What is a normal lecithin to sphingomyelin ratio for a baby with mature lungs?

Back 2

≥2.0

Front 3

CGG repeats

Back 3

Fragile X syndrome

Front 4

Fragile X Syndrome:
Pathophys

Back 4

Familial MR Gene 1 on X chromosome has inc'd number of CGG repeats

Leads to hypermethylation and subsequent gene inactivation

DOES NOT RESULT IN INC'D CHROMOSOMAL BREAKAGE/INSTABILITY

Front 5

Define polyploidy.

Back 5

When more than 2 complete sets of homologous chromosomes exist within an organism or cell.

Ex: Hydatidiform moles have 69 chromosomes (a factor of 23)

Front 6

Define pleiotropy.

Back 6

Occurrence of multiple phenotypic manifestations, often in different organ systems, as a result of a single genetic defect.

Front 7

What is the Pygmalion effect?

Back 7

Researcher's beliefs in efficacy of tx that can potentially affect outcome

Front 8

What is Berkson's bias?

Back 8

Selection bias created by selecting hospitalized patients as control group

Front 9

Schizophrenia:
Presentation
How does it differ from a Schizophreniform Disorder?

Back 9

Recurrent episodes of active psychosis and decline in functional capacity

Presentation includes hallucinations, delusions, disorganized thought, negative syx (blunted affect, social withdrawal, and anhedonia)

When above syx are present for 1-6 months, diagnosis is schizophreniform disorder.

Front 10

Describe and explain the urinalysis findings of diabetic ketoacidosis.

Back 10

Urine pH will decrease

HCO3- will be conserved in the body, and thus will be low in urine

H2PO4- is used to transport H+ out of body, so will be inc'd in urine

Front 11

What are the 4 hypersensitivity reactions?

Describe and provide examples.

Back 11

I: Immediate allergy (IgE)--atopic dermatitis, anaphylaxis, asthma

II: Cytotoxic, Ab-dependent (IgM or IgG)--autoimmune hemolytic anemia, thrombocytopenia, Erythroblastosis fetalis, Goodpasture's, Graves', Myasthenia gravis

III: Immune complex (IgG)--Serum sickness, RA, SLE, Hypersensitivity

IV: Delayed-type hypersensitivity, cell-mediated immune memory response, Ab-dependent (MEDIATED BY T CELLS)--CONTACT dermatitis, Mantoux Test (PPD), chronic transplant rejection, multiple sclerosis

Front 12

Transdermal candida extra injected into pediatric patient.

48 hours later, patient returns with firm nodule.

What cell type responsible for this?

Back 12

T lymphocytes

Front 13

Which hypersensitivity reactions rely on B-lymphocytes?

Back 13

Type I--asthma, anaphylaxis (IgE mediated)
Type II--antibody mediated (ABO incompatibility hemolysis)
Type III--immune complex (post-strep GN!!)

Front 14

Describe the fates of pyruvate in aerobic and anaerobic conditions.

List enzymes necessary.

Back 14

Pyruvate-->Acetyl-CoA in presence of Oxygen via PYRUVATE DH

Pyruvate-->lactate in lack of Oxygen vis LACTATE DH

Front 15

Pyruvate dehydrogenase deficiency:
Dietary restrictions

Back 15

Patients should restrict themselves to a ketogenic diet (as opposed to glucogenic, i.e., aa's that contribute to formation of pyruvate and then lactate. Don't want pts in lactic acidosis!)

Such aa's are lysine and leucine.

Front 16

Glucogenic vs Ketogenic amino acids:
General

Back 16

Glucogenic--produce intermediates of citric acid cycle or pyruvate

Ketogenic--produce acetoacetate or precursors

Ex: leucine, lysine are exclusively ketogenic and will not increase formation of lactic acid

Front 17

Valsalva maneuver:
Therapeutic utility

Back 17

Valsalva maneuver increases vagal tone and can be used to abolish paroxysmal SVT

Front 18

DKA:
Treatment Protocol

Back 18

-Bolus of short-acting regular insulin
-Infusion of insulin adjusted to blood glucose levels
-IV fluids and correct electrolyte imbalances

Front 19

Rapid-acting vs Regular insulin:
Peak time of effect
Examples

Back 19

Rapid-acting: Peak effect within 30 minutes-1 hour; ex: Lispro

Regular: Peak effect around 3 hours, ex: regular insulin

Front 20

Intermediate insulin:
Peak time of effect
Example

Back 20

Peak effect at 6-8 hours, lasts up to 16 hours

Ex: NPH, Lente

Front 21

This insulin lasts 18-24 hours and does not peak.

Back 21

Glargine (Lantus)

Front 22

Apoptosis:
Extrinsic vs Intrinsic Pathways

Back 22

Extrinsic: Death receptor, Fas, binds Fas-L-->produces protein called FADD-->activates caspases

Intrinsic: anti-apoptotic proteins Bcl2 and Bcl-x that reside in mitochondria replaced with Bak, Bax, Bim. Pro-apoptotic pathway allows for inc'd perm of mitochondria-->release of caspase-activating substances like cytochrome C.

CYTOCHROME C!

Front 23

Vitamine E deficiency:
Effects
Presentation
Cause

Back 23

Degeneration of spinocerebellar tracts, dorsal column, peripheral nerves
Mimics Friedreich ataxia bc same areas of CNS affected

Presentation: Ataxia, dysarthria, loss of position AND vibration sense

Front 24

Chronic fatigue
Mild weight gain
Elevated creatine kinase

Back 24

Hypothyroidism

Elevated creatine kinase due to hypothyroid myopathy

Front 25

Hemiplegia
Aphasia
Brain CT hypodensity

Back 25

Ischemic infarct

Front 26

What cells are involved in repair of brain infarct?

Back 26

Neutrophils followed by macrophages (MICROGLIA)

Macs phag debris, dead tissue

CNS repair by astrocytes that migrate to area of necrosis within 2 weeks

Will form cystic space surrounded by astrocytes (GLIOSIS)

Front 27

Formula for flow of incompressible fluid through a cylinder.

Back 27

Total Flow = Flow Velocity x Cross Sectional Area = Constant

Front 28

Lactase:
Reaction catalyzed

Back 28

Lactase:
Lactose ((galactosyl beta-1,4-glucose)-->Galactose + Glucose

Front 29

Neisseria meningitidis:
Route of infection

Back 29

Exposure to respiratory droplets or direct contact with respiratory secretions-->pilus-mediated adherence to, and penetration of mucosal epithelium-->circulation

Note: N. meningitidis produces an IgA protease that facilitates survival of organism in mucosa by destroying IgA ab's

Front 30

Cat scratch fever:
Cause
Effects

Back 30

Bartonella

Can also present with bacillary angiomatosis, culture negative endocarditis

Front 31

How does HIV-1 become resistant to anti-retroviral drugs?

Back 31

Pol gene mutations result in resistance fo HIV reverse transcriptase inhibitors and HIV protease inhibitors

Front 32

Cardiac AEs of TCAs

Treatment?

Back 32

TCAs have quinidine-like effect:
QRS and QT prolongation
Due to inhibition of fast Na+ channels

Tx: Sodium bicarb to correct QRS prolongation, reverse hypotn, tx ventricular dysrhythmias

Front 33

Treatment for benzodiazepine toxicity.

Back 33

Flumazenil

Front 34

Back 34

Blastomyces (broad based budding)

Front 35

Back 35

Coccidoides--large spherule filled w/endospores

Front 36

Most common cause of sudden cardiac death in young, healthy individual.

Back 36

Hypertrophic cardiomyopathy resulting in ventricular tachycardia that deteriorates to ventricular fibrillation

Front 37

Enoxaparin:
Drug Class
MOA

Back 37

LMWH
Binds and activates anti-thrombin III, which binds to factor Xa and stops it from converting prothrombin to thrombin

Front 38

This structure supplies the ovary with nerves and vessels.

Back 38

Suspensory ligament

Front 39

Round ligament:
Locations

Back 39

Uterus (contains artery of Sampson; rarely source of major bleeding during surgery)
Liver

Front 40

This structure supplies contains the uterine artery.

Back 40

Transverse cervical ligament

Front 41

Fenoldopam:
MOA

Back 41

Dopamine-1 receptor agonist-->arteriolar dilation and natriuresis

Leading to dec'd systemic vasc resistance and bP reduction

Also improves renal perfusion

Front 42

Which penicillins are resistant to peniciliinase?

Use?

Back 42

Nafcillin
Methicillin
Oxacillin

Use to tx Staph aureus (not not MRSA), ex: folliculitis, abscesses

Front 43

Back 43

Dec'd compliance in LV (mitral in question stem)-->inc'd risk pulmonary edema

Front 44

This molecule has 220 times more affinity for hemoglobin than does oxygen.

Back 44

Carbon MONOxide

Front 45

Treatment of CO poisoning.

Back 45

100% or hyperbaric oxygen

Front 46

Spontaneous hemarthroses
Easy bruising

Back 46

Hemophilia A

Front 47

Hemophilia A:
Pathophys
Presentation
Treatment

Back 47

Factor VIII deficiency

(A--ATE--EIGHT)

Presents with spontaneous hemarthroses, bleeding after dental procedures, easy bruising

Tx: Desmopressin

Front 48

Desmopressin:
MOA in Hemophilia
Other uses

Back 48

Stimulates release of Factor VIII and vWF from ENDOTHELIAL cells (temporarily increases plasma FVIII by 2-3 times)

Desmopressin is a synthetic analog of ADH, so used in tx of diabetes insipidus to inc reabsorption of water in collecting tubules

Front 49

Goodpasture Syndrome:
Pathophys
Light vs Immunofluorescence findings

Back 49

Goodpasture: Anti-GBM Abs react with Collagen Type IV on GBM

Light findings: Glomerular crescent formation

Immunofluorescence: Linear deposits of IgG and C3 along BM

Front 50

Functional Mitral Regurgitation:
What is it?
Cause?

Back 50

Heart murmur in absence of valve lesion

Dilatation of LV in response to inc'd preload can result in fnal mitral regurgitation--eliminated by preload reduction and reduced by afterload reduction (diuresis!)

Front 51

Describe the breakdown of glucose to pyruvate.

RLS?

Back 51

Glucose
Glucose 6-phosphate
Fructose 6-phosphate
**VIA PFK-1 (RLS)**
F-1,6-Bisphosphate
-->-->Pyruvate

Front 52

Describe the breakdown of galactose to pyruvate.

RLS?

Back 52

Galactose
Galactose 1P
Glucose 1P
Glucose 6P
Fructose 6P
**VIA PFK-1 (RLS)**
F-1,6-bisphosphate
-->-->Pyruvate

Front 53

Which monosaccharide does not require PFK1 for metabolism to pyruvate?

How does this affect rate of glycolysis?

Back 53

Fructose

Rapidly metabolized bc bypasses PFK-1--the RLS of glycolysis

Front 54

Filtration Fraction:
Equation, Subequations
Normal Value

Back 54

FF = GFR/RPF
Normal = 0.2 or 20%

GFR can be calculated by: creatinine OR inuline clearance, or Starling equation

Cx = Ux * V/plasma [ ]

Starling:
GFR = Kf ((Pg - Pb) - (πg - πb))

Where P = hstatic P
Where π = oncotic P
Where G = Glomerular Capillaries
Where B = Bowman's space

RPF:
Use clearance of PAH

Front 55

Back 55

FF = [(200 x 1.0) /2] / [(100 x 1.0) / 0.2] = 100/500 = 0.2 = 20%

Front 56

Leuprolide:
MOA
Effects
Use

Back 56

GnRH hormone administered in constant levels; used to dec both T and DHT levels

When GnRH administered constantly and not in pulsatile fashion:
-Initial increase in release of FSH/LH-->initial increase in T and DHT

But then results in suppression of pituitary release of gonadotropins, causing dec'd DHT and T

Front 57

This drug causes a discordant decrease in DHT compared to T.

Back 57

Finasteride bc inhibits T-alpha reductase

Front 58

Rickets:
Histologic hallmark

Back 58

Unmineralized osteoid matrix, widened osteoid seams

note: there is normal architecture unlike osteoporosis

Front 59

Osteoporosis:
Histologic hallmark

Back 59

Trabecular thinning with few interconnections (abnl architecture)

Front 60

What determines whether a coronary artery plaque qill cause ischemic myocardial injury?

Back 60

Rate at which occludes the involved artery

A slowly developing occlusion will allow for formation of collaterals that could prevent myocardial necrosis

A thin fibrous