Alpha,-lipoprotein

Ishikawa T, McNeeley S, Steiner PM, et al. 1978. Effects of chlorinated hydrocarbon on plasma alpha-lipoprotein cholesterol in rats. Metabolism 27(1) 89-96. 

K4. Kocen, R. S., Lloyd, J. K., Lascelles, P. T., Fosbrooke, A. S., and Williams, D., Familial alpha-lipoprotein deficiency (Tangier disease) with neurological abnormalities. Lancet 1, 1341 (1967). 

The use of surface active agents often modifies the charge of the protein irreversibly through formation of complexes, and because of this a careful study of lipoproteins may prove useful, since anionic detergents influence alpha-lipoproteins, and cationic detergents, beta-lipoproteins (A7, M17). 

Familial alpha-lipoprotein deficiency (Tangier disease, fish-eye disease, apo-A-I and C-III deficiencies)... 

Alphaj-acid glycoprotein (orosomucoid) Alpha-lipoproteins Thiostatin Alpha2 globulins... 

Liver disease is a major cause of all kinds of abnormal lipoproteins. In lipoprotein electrophoresis it often causes a boring pattern no alpha-lipoproteins and a very broad beta-band. The latter is due to a host of abnormal or abnormally composed lipoproteins. In summary, we find decreased alpha-lipoproteins, a dissociation of A-I and A-II (a rare instance of the presence of LP-A-II) decreased LP-B, abnormal VLDL, poor in Apo-C, remnants in the LDL-class, and LP-X. 

The striking fact of an almost complete absence of alpha-lipoproteins is not accompanied by a complete lack of the corresponding apolipoproteins. They are decreased, however, and are part of different particles as judged by immunoelectrophoresis against anti-A-I and anti-A-II. After surgical removal of a gallstone, A-I and A-II become part of the same particle. 

Travia, L. Correlative variations of total lipemia, total cholesterolemia and the beta alpha lipoprotein ratio in humans of excess weight due to hypemutrition. Nutr. et Dieta (Basel) 6, 21—30 (1964). 

Some information is available relating to the role of niacin in athero-.sclerosis and toxemia of pregrancy. Parsons et al. (1956a, b) described a significant decrease of cholesterol levels in some patients with hypercholesterolemia on administration of 1-4 gm. of niacin a day. The concentration of the total lipids and the beta alpha lipoprotein ration decreased also, Niacin proved to be the active factor niacinamide in comparable doses did not have this effect. Similar results were observed by Galbraith et al. (1959) in patients with atherosclerosis as well as with healthy young students. Discontinuing the niacin resulted immediately in return to the previous levels. 

This term is a layman s designation for blood cholesterol which is carried on alpha-lipoproteins, in contrast to that carried on beta-lipoproteins. However, the cholesterol molecule itself does not vary, only the lipoprotein which carries it in the blood. 

Also see ALPHA-LIPOPROTEINS BETA-LIPOPROTEINS CHOLESTEROL and HEART DISEASE.)... 

It is important to differentiate tetween the ways in which cholesterol is conveyed in the blood, tecause that carried on teta-lipoproteins is much more likely to te deposited in the walls of blood vessels than that terne by alpha-lipoproteins. 

Special fat-carrying proteins which are produced in the liver. Beta-lipoproteins are also called low density lipoproteins (LDL). Normally, they contain from 10 to 50% triglycerides, 22 to 45% cholesterol, 18 to 22% phospholipid, and 9 to 21% proteins. It is not desirable for one to have a high blood level of beta-lipoproteins because the cholesterol they carry may be deposited in the blood vessels. However, alpha-lipoproteins (HDL) convey cholesterol in a much more stable complex, so that there is little risk of cholesterol deposits when the blood levels of these proteins are elevated. It appears that the levels of beta- lipoproteins may be reduced, and those of alpha-lipoproteins raised by (1) loss of excess body weight, (2) strenuous physical exercise, (3) a diet low in animal fats and cholesterol, (4) drugs such as clofibrate and niacin (this vitamin must be administered in large doses to achieve the desired effects), and (5) moderate amounts of alcohol. 

This measurement is often used for assessing the risk of heart disease. However, it is sometimes misinterpreted because cholesterol does not travel by itself in the blood, but is carried by complex molecules called lipoproteins. For example, beta- lipoproteins, when elevated in the blood, are associated with increased risks of heart disease and stroke whereas, a high level of alpha-lipoproteins is apparently a good sign. Hence, the measurement of blood cholesterol alone Is at best a very crude measurement of the status of cholesterol metabolism in the body. 

The lipoproteins are classified as chylomicrons, very low density lipoproteins (VLDL), low density lipoproteins (LDL), or high density lipoproteins (HDL)—according to their density, from least dense to most dense. They are also named prebeta-lipoproteins (VLDL), beta-lipoproteins (LDL), and alpha-lipoproteins (HDL), based upon their migration on paper subjected to an electrical field—electrophoresis. 

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