Exam2, biochem, choudhury Flashcards Preview

Year 2 CV > Exam2, biochem, choudhury > Flashcards

Flashcards in Exam2, biochem, choudhury Deck (66):
1

Patient has muscle weakness with elevated amounts of TGL and primary long chain fatty acids many lipid vacuoles in muscle biopsy probable Dx?

carnitine deficiency.

2

What breaks down TGL and what are the products.

hormone sensitive lipase breaks TGL into glycerol and fatty acids.

3

what stimulates hormone sensitive lipase? inhibits?

epi and cortisol inhibited by insulin

4

where and how is glycerol converted to glucose.

in liver, via DHAP (gluconeogenesis)

5

.what stimulates gluconeogenesis

increased glucagon and cortisol

6

what converts FA to Acetyl CoA and where

Beta oxidation in the liver

7

what is Acetyl CoA used for

ketones and kreb cycle

8

Where are ketones primarily used for energy

cardiac muscle and brain tissue

9

what oxidation is used when Beta oxidation is defective

w oxidation, minor catabolic pathway for medium chain fatty acids

10

what is beta oxidation

process whihc FA are broken down in mitochondria to generate Acetylo CoA

11

how do short and medium chain FA enter mitochondria for beta oxidation

.diffuse freely into mitochondria

12

how do long chain FA eneter mitochondria

transported by carnitine shuttle to be oxidized

13

how do very long chain FA get oxidized

peroxisomes

14

How much energy is required to activate FA

2 high energy bonds

15

how does Long chain FA cross outer mitochondrial membrane

FA transporter

16

what is first enzyme required to activate FA in between mitochondrial layers

fatty acyl CoA synthetase that binds FA to CoA

17

how does FA CoA cross inner mitochondrial membrane

it doesnt first CoA is switched for carnitine via the carnitine acyltransferase 1 CPT-1 enzyme then Fa-carnitine gets shuttle across in carnitine transporter

18

What enzyme is inside mitochondria to convert carnitine back to CoA

Carnitine acyltransferase-2 CPT II

19

what does the converstion of Fa CoA to Acetylo CoA generate

FADH2 and NADH

20

what are signs of a myopathic CPT deficiency

muscle aches and weakness myoglobinuria prolonged exercise increased mm TGL

21

what are signs of MCAD deficiency medium chain acyl CoA dehydrogenase

fasting hypoglycemia no ketone bodies C8-C10 acyl carnitines in blood vomiting coma, death

22

how are CPT I and II deficiencys treated

avoiding fasting, dietary restrictions of long chain FA, carnitine supp

23

Which cPT deficiency is most common and assoc signs?

CPT II muscle weakness upon exercise, hyperammonemia,death

24

what can cause carnitine deficiency

inadequate intake inability to metabolize from enzyme deficiency decreaed endogenous synthesis from liver disorder excess loss (diarrhea, diuressis) hereditary disorder of leakage (primary carnitine deficiency) icnreased requirements for carnitine(sepsis) decreased muscle carnitine from mitochondrial impairment

25

how are carnitine and or CPT deficiencies diagnosed

extreme reduction in plasma and muscle carnitine levels hypoglycemia muscle biopsy reveals significant lipid vacuoles

26

what does fasting ketogenesis tell you about carnitine disorders

if it is normal then carnitine transport is normal impaired when dietary carnitine intake interupted

27

brown urine, muscle pain in arms and legs during soccer (goes away at night) normal stature well fed sent home with recommendation to take dietary carnitine. most likely Dx?

CPT-II deficiency

28

what age group does MCAD usually manifest

first 3-5 yrs of life

29

what are xanthomas

lesions characterized by accumulation of lipid laden macrophages

30

what are the types of primary hyperlipoproteinemia

I- familial lipoprotein lipase deficiency II- hyperlipidemia III- familial dysbeta-lipoproteinemia IV-familial hyperTGLemia V

31

what are other causes of hyperlipoproteinemia

decreased synthesis of HDL, hepatic lipase deficiency

32

what will type I hyperlipidemia look like

severe elevation of chylomicrons in plasma increase plasma TGL levels no increase in plasma cholesterol early childhood with acute pancreatitis eruptive xanthomas

33

steatorhea is indicative of what underlying malfuncntion

something wrong with pancreas

34

What causes type IIa hyperlipidemia

accumulation LDL from familial LDL-R deficiency and familial defective apo B100`

35

what are signs of type IIa hyperlipidemia

increased plasma cholesterol and TGL manifest severe atherosclerosis can have tendinous xanthomas or tuberous and xanthelasmas

36

What causes type IIb hyperlipidemia

defective apoB100 protein

37

what are signs of type IIb hyperlipidemia

accumulation of both LDL and VLDL variable elevations in TGL and cholesterol may have tendinous xanthomas or tuberous and xanthelasmas

38

what causes type III hyperlipidemia

various mutations of opo-protein E impaires ability to bind IDL R

39

what are signs of type III hyperlipidemia

accumulation IDL increase in TGL and cholesterol premature atherosclerosis and xanthomas

40

what are signs of type IV hyperlipidemia

plasma cholesterol is normal eruptive xanthomas assoc with coronary heart disease, DM II, obesity and alcholism

41

what causes type IV hyperlipidemia

overpdocution VLDL

42

what causes type V hyperlipidemia

genetic defects of apo-lipoprotein C-II gene

43

what are signs of type V hyperlipidemia

accumulations of chylomicroms and VLDL severe elevations of TGL in plasma present in early childhood similar to type I with acute pancreatitis and eruptive xanthomas

44

what causes decreased synthesis of HDL

decreased formation of apo A-I and apo C-III

decreased reversed cholesterol transport

increased LDL levels

45

What does a hepatic lipase deficieny look likw

coronary heart disease, xanthomas

accumulation of large TGL rich HDL and VLDL

46

what other diseases can lead to secondary hypercholesterolemia

pregnancy

hypothyroidis,

cholestasis

acute intermittent porphyria

47

what other conditions/diseases can lead to secondary hyperTGLemia

DM

pancreatitis

gout

type I glycogen storage disease

alcoholism

oral contraceptive use

48

what conditions can lead to hyper choelsterolemia and hyper TGLemia

nephrotic syndrome

chronic renal failure

steroid immunosuppressive therapy

49

what is xanthelasma palpebrarum

soft velvety flat yellow lesions associated with hyperlipidemia

secondary to cholestasis

50

what are tuberous xanthomas

firm painless red yello nodules that develop in pressure areas like the extensor surface of knees and elbows

associated with hypercholesterolemia and increased levels of LDL

secondary to nephrotic syndrome and hypothyroidism

51

what is tendinous xanthomas

associated with secere hypercholesterolemia and elevated LDL levels

lesions related to trauma

nodules related to tendons or ligaments

secondary to cholestasis

52

what are eruptive xanthomas

crops of small red-yellow papules that may spontaneously resolve over weeks

associated with hyperTGLemia

seconary to DM

53

what are plane xanthomas

associated with dysbetalipoproteinemia

cover large areas of face neck thorax

seconary to cholestasis

54

how do you evaluate if patient has hyperlipoproteinemia

measure plasma lipid and lipoprotein levels after overnight fast 12-16 hours

abnormal lipoprotein patterns need to be identified

electrophoresis and ultracentrifugation of whole plasma for Dx

 

55

What are Tx for hyperlipoproteinemia

dietary

lipid lowering agents: statins, fibrates, bile acid binding resins, probucol or nicotinic acid

56

when to eruptive, tuberous, and tendinous xanthomas clear up

eruptive resolve in weeks of systemic Tx

tubuers after months of Tx

tendinous take years to resolve or may persist indefinitely

57

majority of cholesterol is made or taken in diet? where in the body is it made?

majority is made in body

all nucleated cells can synthesize cholesterol in the ER and cytosol

58

What is HDL-C

scavenger to lwoer serum cholesterol

59

what is LDL-C

transporter for cholesterol from liver to peripheral tissues

60

what is HDL

transporter of cholesterol from peripheral tissues to liver for degradation

61

What can prolonged elevated levels of cholesterol in plasma lead to

artherosclerosis

DM

62

What are statins

act as competitive inhibitors of HMG-CoA reductase so that it cannot be converted to mevalonate so inhibiting cholesterol biosynthesis

63

what is niacin

vit B3

inhibits release of FFA from adipose decreaseing VLDL synthesis and inhibting secretion so decreased LDL production and increased HDL by unknown mechanism

64

what are fibrates

lower plasma TGL by decreased secretion of TGL and VLDL by liver

65

what are ezetimibes

reduce blood cholesterol levels by inhibiting absorption of cholesterol by intestine

names: setia or ezetrol

66

What are resins

bile acid sequestrants

promote excretion of bile acids in stool

diverts cholesterol to bil acid synthesis

up regulates LDL R and enhanced LDL clearance from plasma

names: cholestyramine, colestipol and colesevelam