F2: Lipids

620

Cholesterol is measured after 30 minutes and absorbance is read at ____nm using pure cholesterol as the calibrator.

chloroform

triglycerides are first extracted quantitatively with ____________ to remove water-soluble interfering substances, such as glucose and glycerol, from the serum.

570

The absorbance of chromogen in the reaction for triglyceride determination is measured at _______nm

Ultracentrifugation

Reference method for HDL cholesterol

500

The absorbance measured of cholesterol in the visible portion of the spectrum, generally at about ____nm.

micelles

Amphipathic lipids aggregate with bile acids and form _________

Intraluminal Phase/Digestive Phase

Phase where dietary fats are modified both physically and chemically before absorption

Cellular Phase/Absorptive Phase

Phase where digested material enters intestinal mucosal cells

Triglycerides (Triacylglycerol)

Compose of 3 molecules of fatty acids and a molecule of glycerol (serves as backbone)

most prevalent glycerol esters encountered in the body

Triglycerides

Main storage form of Lipid in man (found in adipose tissues)

Cholesterol

is a sterol that has a tetracyclic perhydrocyclopentanophenanthrene skeleton and contains one unsaturated carbon double bond and one primary alcohol, thus making it an amphipathic lipid

Cholesterol

Not readily catabolize by most cell therefore does not serve as a source of fuel

Esterified Cholesterol

approx. 60-70% of the total cholesterol of the body and is composed of cholesterol ring and a fatty acid

Free Cholesterol

approx. 30- 40% of the cholesterol in the body.

cholesterol ring only and no fatty acids

ATP binding cassette transporter G5/G8

Absorption of cholesterol and phytosterols is limited by the presence of a sterol efflux transporter called the______________________

Phospholipids

Structurally similar to triglyceride except that it is composed of 2 fatty acids and a phospholipid head group is attached to the glycerol backbone instead of 3 fatty acids

Phospholipids

Can be found in the lungs as surfactant during respiration

lysophospholipid

A phospholipid that has lost one of its O-acyl groups is called a _____________

70%- 75%

Phosphatidylcholine percentage

18%-20%

Sphingomyelin percentage

4%- 9%

Lysosphosphatidylcholine percentage

3%- 6%

Phosphatidylserine percentage

Fatty Acids

Building blocks of lipids and a hydrocarbon chain with terminal COOH group where labeling or carbon atoms takes place

Saturated fatty acids

Fatty acids with no double bonds between carbons

Unsaturated fatty acids

Fatty acid with double bonds usually in cis form

Polyunsaturated fatty acids

Fatty acid that contain more than one double bond

Lipoproteins

Transports lipids

apolipoproteins

Lipoproteins contain one or more specific proteins, called _______________

Chylomicron

Largest and lightest among the lipoproteins with the lowest density

Transporter of dietary lipids

Chylomicron

80%-90% of triglyceride by weight

Very Low Density Lipoproteins

Pre-beta lipoprotein

Assembled in the liver for energy needs and storage of fats

It transports endogenous triglycerides

Low Density Lipoprotein

Also known as “bad cholesterol” - Contains mostly Apo B-100 and its measurement can serve as a surrogate for LDL particle concentration

Low Density Lipoprotein

Transports majority of 75% of the

cholesterol from liver to the cells

directly

LDL is ________proportional to the risk of atherosclerosis

inversely

HDL is _____________inversely proportional to the risk of atherosclerosis and coronary heart disease

High Density Lipoprotein

Smallest and heaviest among lipoproteins

Also known as “good cholesterol”

High Density Lipoprotein

Fastest towards the anode; aka alpha lipoprotein

Apo A-1

The major protein of HDL is the _______

HDL

Responsible for reverse cholesterol transport (cells to the liver)

Intermediate Density Lipoprotein

Formed through the metabolism of VLDL in the circulation

The lipid content, size, and density of IDL are intermediate between VLDL and LDL

The concentrations of IDL contributes to the development of coronary heart disease

Lp (a)

\-Also known as the sinking pre-beta lipoprotein

Found in the LDL density range in ultracentrifigation but moves in the pre-beta region during electrophoresis

Beta VLDL

also known as the floating beta lipoprotein

Richer in cholesterol than triglyceride

Found the VLDL density range but migrates electrophoretically with or near LDL

Beta VLDL

Seen in patients with type III hyperlipoproteinemia

LpX

Abnormal lipoprotein that is rich in lipids primarily unesterified cholesterol and phospholipid

Migrates towards the cathode during agar electrophoresis

LpX

Found in patients with obstructive biliary disease; regurgitation of biliary contents in the bloodstream which results in the build- up of LpX.

Electrophoresis (Fredrickson- Levy reaction)

Separates lipoproteins based on their electric charge

Sudan Black B

Oil Red O

Fat red 7B

Stains for lipoproteins

Ultracentrifugation

Separates lipoproteins based on their densities and it is the reference method for lipoprotein analysis

Immunochemical methods

Use of antibody directed towards specific apolipoproteins (anti-apoA1, anti-apoC, etc.)

SVEDBERG unit

Unit of sedimentation rate

Organic Solvent

Reagent in Extraction Method of Triglyceride Analysis

Acetic anhydride + Sulfuric acid

Reagent in

Liebermann- Burchard Reaction

Sulfuric acid + Ferric iron

Reagent in

Salkowski reaction

Cholestedieny l monosulfonic acid

End product in Liebermann- Burchard Reaction

Cholestedieny l disulfonic acid

End product in Salkowski reaction

Green (not stable)

End color in Liebermann- Burchard Reaction

Red (stable)

End color in Salkowski reaction

Zlatkis, Zak & Boyle

free cholesterol and cholesteryl ester is a problem in the method.

Carr & Drekter

Chromogen interference and color differences between free cholesterol and cholesteryl ester are problems in a method; protein interference removed

Abell

Protein interference removed; color differences between free cholesterol and cholesteryl ester is removed. Chromogen interference partially removed.

Schoenheimer/ Sperry

Protein and chromogen interference were removed; color differences between free cholesterol and cholesteryl ester is removed.

VLDL

plasma sample that remains turbid after standing overnight indicates increased _____

10x75mm

2mL of plasma is placed in ______ test tube and allowed to stand in the refrigerator at 4oC undisturbed overnight.

LDL=total cholesterol–HDL– (triglycerides/5)

LDL formula

TAG/5

is used if the unit used is mg/dL

TAG/2.175

is used if the unit used is mmol/L

Phospholipase D

Phospholipid is hydrolyzed using phospholipase D into Choline

Choline oxidase

Choline is oxidized into betaine and hydrogen peroxidase

Peroxidase

hydrogen peroxidase is mixed with phenol and 4-aminoantipyrine to form quinonimine dye (measured at 500nm)

Arteriosclerosis

general term for thickening and hardening of arteries (hard arteries)

Atherosclerosis

a type of arteriosclerosis caused by plaques that build up inside the arteries; involves large and medium-sized arteries

Coronary Heart Disease

Refers to the broad spectrum of heart disease resulting from impaired coronary blood flow.

Analphalipoproteinemia

Also known as “Tangier Disease”

Analphalipoproteinemia

Also known as “Tangier Disease”

 A rare autosomal recessive disorder characterized by complete absence of HL due to mutation in the ABCA1 gene on chromosome 9.

 Leads to an inability to effectively cholesterol and phospholipids from within the cell into nascent apoA1 proteins in plasma.

Abetalipoproteinemia

Also known as “Bassen-kornzweig Syndrome”

\

apoB (B48 and B100)

Abetalipoproteinemia is a deficiency of _____

Type I

Creamy layer on clear plasma

Type I

Extremely elevated TG due to the presence of chylomicrons

Type IIa

Clear

Type IIa

Elevated LDL

IIb

Elevated LDL and VLDL

III

Elevated Cholestero l Tg: Presence of B- VLDL

Type IV

Elevated VLDL

Type IV

Clear or Turbid

Type V

Elevated VLDL and presence of chylomicrons

Type V

Creamy layer on turbid plasma

Fabry’s disease

Alpha galactosidase is deficient in

GM-1 gangliosidosis

Beta galactosidase is deficient in

Gaucher

Beta glucosidase is deficient in

Niemann Pick

Sphingomyelinase is deficient in

Metachromatic

leukodystrophy

Arylsulfatase A is deficient in

Sandhoff

Total hexosaminidase (hexosaminidase A and B) is deficient in

Tay Sach

Hexosaminidase A is deficient in

140-200mg/dL

Reference Range for Total cholesterol

29-60 mg/dL

Reference range for HDL cholesterol in male

38-75mg/dL

Reference range for HDL cholesterol in female

57-130 mg/dL

Reference range for LDL cholesterol

67-157 mg/dL

Triglyceride Reference Range

0\.026

Cholesterol (mg/dL to mmoL/L) conversion factor

0\.0113

Triglyceride (mg/dL to mmoL/L) conversion factor