CC2 (LIPID AND LIPOPROTEIN ANALYSES) Flashcards

1
Q

SAMPLE for cholesterol measurement

A

plasma or serum

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2
Q

PATIENT PREP for cholesterol measurement

A

usual diet 2 weeks prior testing

May be tested from nonfasting spx (little effect on TC)

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3
Q

May be tested from nonfasting spx

A

CHOLESTEROL

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4
Q

PRECAUTIONS for cholesterol measurement

A
  • Avoid hemolyzed sample (free Hgb – false ↑)
  • Avoid icteric sample
  • No water contamination (dehydration is included in chole measurement)
  • Precise and accurate timing for color development
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5
Q

COLOR DEVELOPER MIXTURE FOR CHOLE:

A
  • Glacial acetic acid
  • Acetic anhydride
  • Conc. sulfuric acid
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6
Q

These makes it possible for the cholesterol to be carried out in colorimetric assay

A

Double bonds and hydroxyl group in the sterol structure

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7
Q

CDC Reference method for CHOLESTEROL

A

ABELL-LEVY-BRODIE-KENDALL METHOD

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8
Q

Used for cholesterol extraction

A

Hexane

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9
Q

Used for cholesterol hydrolysis

A

Alc. KOH

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10
Q

General steps for cholesterol method

A

Cholesteryl esters: hydrolyzed with alc. KOH

Unesterified cholesterol: extracted with hexane

Measured using: LIEBERMANN – BURCHARD reaction or SALKOWSKI reaction

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11
Q

NON-ENZYMATIC / CHEMICAL METHOD for CHOLESTEROL

A

ABELL KANDALL

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12
Q

Principle: Cholesterol dehydration & oxidation to form a colored compound (measured colorimetrically)

A

NON-ENZYMATIC / CHEMICAL METHODS (ABELL KANDALL)

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13
Q

Involves colorimetry only

A

One-step method

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14
Q

Involves extraction, colorimetry

A

Two-step method

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15
Q

Involves saponification, extraction, colorimetry

A

Three-step method

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16
Q

Involves precipitation, saponification, extraction, colorimetry

A

Four-step method

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17
Q

Chemical reaction after hydrolysis and hexane extraction of cholesterol

A

LIEBERMANN – BURCHARD reaction or SALKOWSKI reaction

Cholesterol + Sulfuric acid + Acetic anhydride –>
LIEBERMANN – BURCHARD: Green soln. (Cholestadienyl monosulfonic acid)

SALKOWSKI: Red soln. (Cholestadienyl disulfonic acid)

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18
Q

Product and solution color in LIEBERMANN – BURCHARD reaction for cholesterol

A

Cholestadienyl monosulfonic acid
Green soln.

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19
Q

Product and solution color in SALKOWSKI reaction for cholesterol

A

Cholestadienyl disulfonic acid
Red soln.

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20
Q

T/F

Color intensity absorbance = Cholesterol concentration

A

T

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21
Q

ENZYMATIC METHOD for CHOLESTEROL

A

CHOLESTEROL OXIDASE

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22
Q

Chemical equation for ENZYMATIC METHOD (CHOLESTEROL OXIDASE)

A

TC (cholesteryl ester and cholesterol) + H2O ▬Cholesteryl esterase▬► Cholesterol + FA

Cholesterol oxidase
Cholesterol + O2 ▬Cholesterol oxidase▬► 4-cholestenone + H2O2

H2O2 + Dye ▬Peroxidase▬► Color (Quinoneimine dye – violet/pink)

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23
Q

End product & color of enzymatic method (Cholesterol oxidase)

A

Quinoneimine dye – violet/pink

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24
Q

SAMPLE for TAG

A

plasma or serum

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25
Q

PATIENT PREP for TAG

A

Strict fasting (12 hours)
If + FBS: 10 hours

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26
Q

Transfer of phosphate group

A

Kinase

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27
Q

CDC Reference method for TAG

A

MODIFIED VAN HANDEL AND ZILVERSMITH

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28
Q

Chemical equation for NON-ENZYMATIC/CHEMICAL METHOD of TAG

A

HYDROLYSIS: TAG ▬Alcoholic KOH▬► Glycerol + FA

Glycerol + Periodic acid ▬▬► Formaldehyde

Formaldehyde + Chromotropic acid → Blue soln (Van Handel and Zilversmith)

or

Formaldehyde + Diacetyl acetone + NH3 → Yellow soln (Hantzch Condensation)

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29
Q

2 methods included in NON-ENZYMATIC/CHEMICAL METHOD for TAG

A

Van Handel and Zilversmith (Colorimetric)
Hantzch Condensation (Fluorometric)

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30
Q

Equation of Van Handel and Zilversmith (Colorimetric)

A

Formaldehyde + Chromotropic acid → Blue soln

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31
Q

Equation of Hantzch Condensation (Fluorometric)

A

Formaldehyde + Diacetyl acetone + NH3 → Yellow soln

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32
Q

T/F
Color intensity absorbance = TAG concentration

A

T

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33
Q

Part of TAG structure utilized in analysis

A

Glycerol

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34
Q

Colorimetric method for TAG
Color of solution

A

Van Handel and Zilversmith
Blue

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35
Q

Fluorometric method for TAG
Color of solution

A

Hantzch Condensation
Yellow

36
Q

ENZYMATIC METHOD for TAG

A

GLYCEROL KINASE

37
Q

Equation for TAG ENZYMATIC METHODS (GLYCEROL KINASE)

A

TAG ▬Lipase▬► Glycerol + FA

Glycerol + ATP ▬Glycerokinase▬► Glycerophosphate + ADP

> PK
Glycerol-Phosphate Oxidase

38
Q

Pyruvate Kinase equation for TAG (enzymatic) utilizing ADP

A

ADP + PEP ▬PK▬► ATP + Pyruvate

Pyruvate + NADH + H+ ▬LD▬►Lactate + NAD+
(340 nm; decreased absorbance)

39
Q

Glycerol-Phosphate Oxidase equation for TAG (enzymatic) utilizing Glycerophosphate

A

Glycerophosphate + O2 ▬GO▬► Dihydroxyacetone + H2O2

H2O2 + Dye ▬Peroxidase▬► Color

40
Q

SAMPLE for LIPOPROTEIN

A

Serum from SST (laboratory)
EDTA plasma (research studies)

41
Q

PATIENT PREP for LIPOPROTEIN

A

Fasting (12 hours)
If nonfasting sample – only test HDL and TC

42
Q

Indicates hyperlipidemia; must be treated using ultracentrifugation or enzymatic cleavage

A

Lipemic (fasting sample)

43
Q

GENERAL METHODS for LIPOPROTEIN

A

ULTRACENTRIFUGATION
ELECTROPHORESIS

44
Q

Reference method for LPP quantitation

A

ULTRACENTRIFUGATION

45
Q

ULTRACENTRIFUGATION of LPP is based on

A

molecular density

46
Q

solution applied during ULTRACENTRIFUGATION of LPP & its SG

A

Potassium bromide (SG 1.063)

47
Q

Method wherein plasma is centrifuged for 24 hrs

A

ULTRACENTRIFUGATION of LPP

48
Q

Resulting layers after ULTRACENTRIFUGATION of LPP

A

Lightest to heaviest:
1) CM
2) VLDL
3) LDL
4) HDL

49
Q

LPP ELECTROPHORESIS is based on

A

migration in an electric field (depends on protein constituent)

50
Q

pH of proteins

A

8.6
*proteins are negative charge

51
Q

Lipid stains used in LPP ELECTROPHORESIS

A

Oil red O
Fat Red 7B
Sudan Black

52
Q

4 bands obtained after fat stain

A

HDL (α-lipoprotein)
VLDL, LP(a)
LDL
CM

53
Q

Fastest (most anodic) lipoprotein

A

HDL (α-lipoprotein)

54
Q

Pre-β lipoprotein

A

VLDL
LP(a)

55
Q

β lipoprotein

A

LDL

56
Q

Lipoprotein stationary at origin (cathode)

A

CM

57
Q

PLASMA PROTEINS

A

A. Albumin
B. Globulin
* α1-globulins
* α2-globulins
* β-globulins
* y-globulins

58
Q

HIGH-DENSITY LIPOPROTEIN (HDL) METHOD

A

POLYANION PRECIPITATION

59
Q

a two-step method including precipitation and Abell-Kendall

A

POLYANION PRECIPITATION (HDL measurement)

60
Q

Polyanion added to serum
(removes non-HDL lipoproteins)

A

Precipitation (POLYANION PRECIPITATION for HDL)

61
Q

Used to quantify HDL

A

Abell-Kendal

62
Q

Examples of Polyanions

A

Heparin
Dextran sulfate
Na phosphotungstate

63
Q

Examples of divalent cations

A

Mg
Mn

64
Q

Lipoproteins (LDL, VLDL) are precipitated with polyanions in
presence of divalent cations (e.g. Mg or Mn), which are sediment by centrifugation (10-30 min. for 10,000g or 3 min. for 15,000g)
HDL is quantified in the supernate by Abell-Kendal (used in cholesterol assay)

A

POLYANION PRECIPITATION

65
Q

Lipoproteins only derived values (computed) in the lab

A

LDL and VLDL

66
Q

LDL computation

A

LDL= Total cholesterol – (HDL + VLDL)

67
Q

VLDL computation

A

Friedewald:
VLDL = TAG / 5 = mg/dL (conventional)
VLDL= TAG / 2.175 = mmol/L (SI)

68
Q

Ultracentrifugation of serum at native density gradient of ______ to float VLDL

A

1.006 g/L

69
Q

Apolipoprotein used for determination of LDL and VLDL conc.

A

Apo B

70
Q

Apolipoprotein used for determination of HDL conc.

A

Apo A-1

71
Q

T/F

Apolipoprotein conc. = Corresponding lipoprotein conc.

A

T

72
Q

TESTS FOR APOLIPOPROTEIN:

A

Immunoassays (Immunonephelometric assay, Immunoturbidimetric assay, Immunochemical assay)

73
Q

Involves specific antibodies (reagent); apolipoproteins (target)

A

Immunoassays (Immunonephelometric assay, Immunoturbidimetric assay, Immunochemical assay)

74
Q

Target in immunoassays for apolipoprotein

A

Apo A-1

75
Q

Reagent used in immunoassays for apolipoprotein

A

Anti-Apo A-1

76
Q

triggers CHD

A

POSITIVE RISK FACTOR

77
Q

POSITIVE RISK FACTOR for CHD:
AGE

A

≥ 45 years for men

≥ 55 years or premature menopause for women

78
Q

POSITIVE RISK FACTOR for CHD:
Hypertension

A

BP ≥140/90 mmHg or
taking antihypertensive medication

79
Q

LDL cholesterol concentration with less than or equal to 1 risk factor

A

≥ 160 mg/dL

80
Q

LDL cholesterol concentration with greater than or equal to 2 risk factor

A

≥ 130 mg/dL

81
Q

LDL cholesterol concentration with CHD or risk equivalent

A

≥ 100 mg/dL

82
Q

POSITIVE RISK FACTOR for CHD:
HDL cholesterol concentration

A

<40 mg/dL

83
Q

CHD risk equivalent (has active lipolysis – stored fats released in serum)

A

Diabetes mellitus

84
Q

LIST OF POSITIVE RISK FACTOR – triggers CHD

A
  • Age: ≥ 45 years for men; ≥ 55 years or premature menopause for women
  • Family history of premature CHD
  • Current cigarette smoking
  • Hypertension: (BP >140/90 mmHg or taking antihypertensive medication)
  • LDL cholesterol concentration: (> 160 mg/dL, with <1 risk factor)
  • LDL cholesterol concentration: (> 130 mg/dL, with >2 risk factor)
  • LDL cholesterol concentration: (> 100 mg/dL, with CHD or risk equivalent)
  • HDL cholesterol concentration: (<40 mg/dL)
  • Diabetes mellitus = CHD risk equivalent (has active lipolysis – stored fats released in serum)
  • Metabolic syndrome (multiple risk factor)
85
Q

NEGATIVE RISK FACTOR for CHD

A
  • HDL cholesterol concentration (> 60 mg/dL)
  • LDL cholesterol (<100 mg/dL)
86
Q

Included in LIPID PROFILE TEST

A
  1. Total cholesterol
  2. TAG
  3. HDL
  4. LDL
  5. VLDL
87
Q

Lipids not routinely measured in the lab

A

Fatty Acids
Phospholipids