Chapter 17 Lipids And Dyslipoproteinemia

Front 1

Which lipoprotein causes "milky" plasma blood cells?

Back 1

Chylomicrons cause milky plasma; when a sample is refrigerated, the CM will form a creamy layer of the top of the sample. VLDL causes cloudy plasma, which is distinct from the milky/creamy plasma that forms during the refrigeration test

Front 2

Which apolipoprotein specific chylomicrons?

Back 2

B-48 is found only in chylomicrons

Front 3

Was the predominant apolipoprotein low-density lipoprotein?

Back 3

B-100 is the key apolipoprotein in LDL. It is also found in VLDL

Front 4

where does high density lipoprotein(HDL) migrate on protein electrophoresis?

Back 4

HDL migrates in the alpha-1 fraction

Front 5

Which alipoprotein activates the enzyme lipoprotein lipase (LPL)?

Back 5

apoC-2

Front 6

31-year-old completes a half iron triatholon , submits blood sample for research protocol on the effects of vigorous exercise on lipids. His triglycerides(TG) are found to be elevated at 232mg/dl. He consumed almost no fat during the race and ate a carbohydrate rich breakfast. Explain?

Back 6

Vigorous exercise can generate free glycerol plasma, interfering with enzymatic triglyceride measurement. To correct for this, a blanking procedure should be performed prior to measuring the subject’s .

Front 7

Reviewed the electrophoretic patterns of the lipoproteins :
CM, LDL, V LDL, HDL

Back 7

Cm=origin, VLDL=pre-beta, LDL=beta, HDL=alpha-1

Front 8

State the Friedewald formula for estimating LDL in mg/dL, state when a direct method would be more accurate?

Back 8

LDL = TC - HDL - TG/5.0 (mg/dL)
if triglycerides are greater than 400 mg/dL then a direct measurement

Front 9

Reviewed the cholesterol oxidase method of measuring cholesterol, how would ascorbic acid result in a falsely low value?

Back 9

ascorbic acid consumes hydrogen peroxide, a reaction product , which is converted to H2O and adye measured at 500nm. less H2O2 would result in less finial product, in this case the dye

Front 10

what is the role of lipoprotein lipase?

Back 10

LPL hydrolyses triglycerides from CM and VLDL. Type 1 hyperlipoproteinemia in the Fredrickson Classification scheme is a deficiency of LPL. This is autosomal recessive disorder. With CM poorly handled in circulation, these patients have milky plasma

Front 11

an overnight fast ensures that which lipoprotein is cleared from plasma in a normal individual?

Back 11

CM should be cleared by 9-12 hours of fasting

Front 12

why is EDTA the preferred anticoqagulant for cholesterol panel when cholesterol and triglycerides levels in plasma are about 3% lower in EDTA- preserved specimens than in serum samples?

Back 12

EDTA retards oxidative and enzymatic changes that occur in lipoproteins during storage.

Front 13

Friedewald formula for estimating LDL

Back 13

LDL-cholesterol= total cholesterol -HDL-cholesterol - TG/5
If TG are greater than 400mg/dL then a direct measurement of LDL is more accurate

Front 14

a patient with dysbetalipoproteinemia has elevated levels of what lipoprotein? what electrophoretic feature helps distinguish this disorder from others?

Back 14

beta -VLDL ; on protein electrophoreesis a broad band between VLDL and LDL is present and distinctive; this is type 3 in the fredrickson scheme

Front 15

according to the AFCAPS trial, which apolipoprotein was found to be the single best lipid, lipoprotein or apolipoprotein measurement to predict coronary artery disease risk?

Back 15

apoB

Front 16

what is the effect of age on cholesterol concentrations in both sexes?

Back 16

cholesterol concentrations increase with again both sexes starting in early adulthood

Front 17

total cholesterol of 287mg/dL, HDL of 22mg/dL, TG of 400mg/dL
LDL?

Back 17

LDL-cholesterol= total cholesterol -HDL-cholesterol - TG/5
287-22-(400/5)=185mg/dL

Front 18

Back 18

Front 19

Back 19

Front 20

premature coronary artery disease is most clearly associated with which types of lipoproteinemia in the Fredrickson Classification?

Back 20

2a&2b=LDL
3=IDL; abdominal and femoral arteries

Front 21

2A (heterozygous and
homozygous familial
hypercholesterolemia)

Back 21

mutation of LDL receptor gene on chromosome 19

Front 22

cholesterol ratio is used to screen for type 3 hyperlipoprotein/dysbetalipoproteinemia?

Back 22

VLDL/TG
normal ratio is 0.2 , in dysbetalipoproteinemia patients this ratio is >0.3 with all their excess VLDL

Front 23

what vitamin deficiency is most pronounced in abetalipoproteinemia and why?

Back 23

vitamin E requires CM for adsorption, VLDL for transport and LDL for delivery into the cells
without the apoB proteins, there is no B-48(this is the major protein in CM-no B-48, no CM based absorption of vitamin E); these patients also are deficient in B-100, a key protein in both LDL and VLDL, so these proteins can not be properly synthesized; patients can develop retinal and peripheral nerve deficits if vitamin E is not replaced

Front 24

25yom body builder has HDL 12mg/dL, HEENT exame is normal; what do you suspect?

Back 24

classic anabolic steroid use; the normal HEENT examination ruled out the orange tonsils of Tangier disease

This, defined as HD L<35 mgldL, is an independent risk factor for premature atherosclerosis . Ahigh HDL, greater than 70 mg/dL, i sprotective. Tangier disease is an autosomal recessive disorder of lipid metabolism characterized by low cho-lesterol, normal to increased TG, absent HDL, an dabsence of APO-A 1 . Cholesterol esters deposit in th etonsils, lymph nodes, vasculature, and spleen, andcorneal opacities develop. HDL cholesterol may als obe reduced by smoking, obesity, sedentary lifestyle,and anabolic steroids

Hint 24