Cholesterol high level

The subsequent conversion of HMG-CoA into MVA involves a two-step reduction of the thioester group to a primary alcohol (see Section 7.11), and provides an essentially irreversible and rate-limiting transformation. Drug-mediated inhibition of this enzyme, HMG-CoA reductase (HMGR), can be used to regulate the biosynthesis of the steroid cholesterol. High levels of blood cholesterol are known to contribute to the incidence of coronary heart disease and heart attacks. 

Cholesterol can be obtained either from the diet or it can be synthesized de novo, mainly in the liver. Cholesterol is transported round the body in lipoprotein particles (see Topic K6). The rate of synthesis of cholesterol is dependent on the cellular level of cholesterol. High levels of cholesterol and its metabolites control cholesterol biosynthesis by ... 

Good cholesterol, high levels associated with low incidence of atherosclerosis... 

Cholesterol (high levels of which in the blood are associated with heart complaints) is soluble in SCCO2, and this medium has been used to extract cholesterol from egg yoUc, meat and milk. There is potential for wider application of SCCO2 in the production of foodstuffs with reduced cholesterol levels. 

Atherosclerosis is a degenerative disease which is characterized by cholesterol-containing thickening of arterial walls. Saturated fatty acids, high levels of cholesterol, elevated blood pressure, and elevated serum lipoprotein are well-knowm risk... 

Compare and contrast two individuals, one of whose diet consists largely of meats containing high levels of cholesterol, and the other of whose diet is rich in plant sterols. Are their risks of cardiovascular disease likely to be similar or different Explain your reasoning. 

Gene expression—cholesterol levels control the amount of mRNA. If [cholesterol] is high, levels of mRNA coding for the reductase are reduced. If [cholesterol] is low, more mRNA is made. (Regulation of gene expression is discussed in Chapter 31.)... 

Elevated levels of cholesterol present in VLDL, IDL, or LDL are associated with atherosclerosis, whereas high levels of HDL have a protective effect. 

Nutritional understanding of the effect of fats in the diet has made considerable progress.26-30 It was understood that saturated fats (see Chapter 3, Section 3.8) were the least beneficial as they raised serum cholesterol. High serum cholesterol is now associated with heart attacks and strokes. There was for this reason pressure over the cholesterol content of foods. This pressure has now been relieved since it appears that dietary cholesterol is not a particularly serious issue. The human body makes cholesterol, so dietary cholesterol does not necessarily affect serum cholesterol level as dietary intake can be compensated for by reduced cholesterol synthesis. 

HDL cholesterol picked up in the periphery can also enter cells through a scavenger receptor, SR-Bl. This receptor is expressed at high levels in hepatocytes and the steroidogenic tissues, including ovaries, testes, and areas of the adrenal glands. This receptor does not mediate endo-cytosis of the HDL, but rather transfer of cholesterol into the cell by a mechanism not yet clearly defined. This process is shown in Figure 1-15-7. 

Fig. 10.5 Apolipoprotein E (APOE)-relsled serum levels of APOE, total cholesterol, high-density lipoprotein (HDL) cholesterol, low-density hpoprotein (LDL) cholesterol, amyloid- 3 peptide (1 2), and histamine in Alzheimer s disease. (Adapted from refs. 12,59, and 289.)...

There is a mutant gene that produces an inactive receptor and patients with this mntant snffer from high levels of LDL-cholesterol in their blood. They have a markedly increased risk of developing atherosclerosis and coronary artery disease. 

Fatty foods also usually contain relatively high levels of cholesterol. 

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