Total and HDL Cholesterol Flashcards
What is total cholesterol composed of? (introduction)
- HDL: high protein content, picks up cholesterol from arteries and return it to liver for excretion
- LDL: high cholesterol content, deposits cholesterol as plaques
How is LDL linked w/ CHD? (introduction)
- LDL forms arterial plaques which is linked with CHD or stroke
Total cholesterol estimation
- 1st enzyme releases all chol
- 2nd enzyme oxidises chol, forms hydrogen peroxide
- 3rd enzyme releases atomic O2 from hydrogen peroxide reacting w/ phenol and 4-aminoantipyrine to produce red quinonimine dye
- Measured at 500nm
HDL estimation
- phosphotungistic acid/MgCl solution added, LDL and VLDL precipitate
- then centrifuged to bottom of tube, HDL still dissolved in supernatant
- chol measured in supernatant will be that of HDL
Equation for both total and HDL cholesterol
- (absorbance of unknown/absorbance of std) x concentration of std = concentration of unknown
Total cholesterol result boundaries
- desirable total chol: <5.17 mmol/L
- borderline high: 5.17 - 6.19 mmol/L
- high: > or = 6.20 mmol/L
Total chol and HDL QC ranges
- total chol: 5.1 - 6.6 mmol/L
- HDL: 0.6 - 1.19 mmol/L
HDL result boundaries
- <1.04 mmol/L = CHD high risk
- > or = 1.55 mmol/L = low risk
Low HDL
- means higher LDL
- LDL causes build up of fatty acids within your arteries, reducing or blocking blood + O2 flow, leading to chest pain and heart attack
- atherosclerosis: not limited to heart arteries, also in arteries elsewhere, causing strokes, kidney failure and poor circulation
Treatments of low HDL
- dietary: reduce saturated fats, trans fats and sugars, increase plant-derived sterols and fibres
- lifestyle: regular exercise, lose weight
- drugs: statins (block chol production in liver itself, lower LDL), ezetimibe (reduces dietary chol absorption), bile-acid-binding resins (prompts liver to use excess chol to make bile acids, reducing chol level
Measuring BP (other ways in determining risk)
- can lead to thickening and hardening of arteries, narrowing them and thus restricting flow
Diabetes (other ways in determining risk)
- share similar risk factors with CHD, such as obesity and high BP
Assessing hs-CRP levels (other ways in determining risk)
- high sensitivity C-reactive protein
- appears in higher amounts when there’s inflammation
- high levels may be risk factor
Lifestyle choices (other ways in determining risk)
- smoking: nicotine and CO puts strain on heart by making it work faster, increase risk of clots, lining of arteries damaged
- lack of exercise: fatty deposits build up in arteries, blocked blood supply to heart/brain = heart attack/stroke
- alcohol use: can lead to heart damage, worsens other risk factors of CHD
Thrombosis (other ways in determining risk)
- blood clot in vein or artery
- if develops in coronary artery it prevents blood supply from reaching heart muscle
Autoimmune diseases (other ways in determining risk)
- those with rheumatoid arthritis and lupus have increased risk of atherosclerosis
Genetics (other ways in determining risk)
- family history
- hereditary
- increased CHD risk
