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Biomedical subjects

H M Sinclair

Publications and source records attributed to H M Sinclair.

At least 19 recordsLinked to original sources
PubMed1990

Red blood cell and adipose tissue fatty acids in mild inactive multiple sclerosis.

The fatty acid profiles of phosphatidyl ethanolamine (PE) and phosphatidyl choline (PC) of the red blood cells of 30 patients with mild inactive multiple sclerosis (MS) and 30 healthy controls were studied by gas chromatography. The groups were well matched for factors likely to influence tissue lipid levels, including diet. The MS patients showed a significant reduction in PE eicosapentaenoic acid (p = 0.009) especially in women, and an increase in both PE dihomo-gamma-linolenic acid (p = 0.004) and PC stearic acid (p = 0.04). No reduction in linoleic acid was observed in either the PC or PE fractions of the MS subjects. A similar study of the fatty acid profile in adipose tissue in 26 MS and 35 healthy controls found no detectable eicosapentaenoic acid in either group. However, whereas docosahexaenoic acid was not detectable in any MS patient, 40% of the controls had measurable levels varying from to 0.1 to 0.3% of total estimated fatty acid (p = 0.0003). No reduction in linoleic acid in MS subjects was observed. Supplementation with oral fish body oil demonstrated that n-3 fatty acids were incorporated into red blood cells over 5 weeks and this occurred equally in MS and controls. The effects of oral supplementation on adipose tissue were studied after 1 and 2 years. Whereas many fatty acids such as linoleic acid were raised at 1 year, but did not rise subsequently, eicosapentaenoic acid and docosahexaenoic acid continued to rise through the 2-year period.(ABSTRACT TRUNCATED AT 250 WORDS)

Adipose Tissue↗
PubMed1984

Essential fatty acids in perspective.

There are two families of essential fatty acids, the linoleic and linolenic. Linoleic acid (C18:2n-6), found mainly in vegetable seed oils, is desaturated and elongated in the body, forming arachidonic acid (C20:4n-6). Linolenic acid (C18:3n-3), the main dietary source of which is leaves, is desaturated and elongated, forming two fatty acids that are prevalent in fish oils: timnodonic (C20:5n-3) and clupanodonic (C22:6n-3). EFA are very easily peroxidized in air, but vitamin E protects against this. There are three functions of EFA. The most important is as part of phospholipids in all animal cellular membranes: in deficiency of EFA faulty membranes are formed. A second is in the transport and oxidation of cholesterol: EFA tend to lower plasma cholesterol. A third function is as precursors of prostanoids which are only formed from EFA. Deficiency of EFA in experimental animals causes lesions mainly attributable to faulty cellular membranes: sudden failure of growth, lesions of skin and kidney and connective tissue, erythrocyte fragility, impaired fertility, uncoupling of oxidation and phosphorylation. In man pure deficiency of EFA has been studied particularly in persons fed intravenously. A relative deficiency (that is, a low ratio in the body of EFA to long-chain saturated fatty acids and isomers of EFA) is common on Western diets and plays an important part in the causation of atherosclerosis, coronary thrombosis, multiple sclerosis, the triopathy of diabetes mellitus, hypertension and certain forms of malignant disease. Various factors affect the dietary requirement of EFA.

Arteriosclerosis↗
PubMed1980

The composition of the Eskimo food in north western Greenland.

In the winter of 1976 an examination of the composition of Eskimo food was carried out in north western Greenland. Duplicate specimens of diets collected from 50 adults, equal numbers of males and females, were analyzed for water, ash, protein, fat, individual fatty acids, cholesterol, and carbohydrate. The results are compared with those of typical Danish diets. Seal and the fish are predominant Eskimo food. Marked differences between Eskimo and Danish food were found. The Eskimo diets were richer in polyunsaturated fatty acids, the ratio to saturated fatty acids was 0.84 as compared with 0.24 in Danes. The polyunsaturated fatty acids were predominantly of the linolenic class (n-3) in Eskimos and the linoleic class (n-6) in Danes. Monoenes other than palmitoleic and oleic acids were high in Eskimo diets, but negligible in Danish. The results are related to previous examinations of the plasma lipids in Eskimos. The rarity of ischemic heart disease in Greenland Eskimos may partly be explained by the antithrombotic effect of the long-chained polyunsaturated fatty acids, especially eicosapentaenoic acid prevalent in diets rich in marine oils.

Adult↗
PubMed1980

Prevention of coronary heart disease: the role of essential fatty acids.

There are 2 classes of essential fatty acids (EFA), the linoleic (n-6) and linolenic (n-3). They are required for the glycerophosphatides (phospholipids) of cellular membranes; the transport and oxidation of cholesterol; the formation of prostaglandins. In deficiency of EFA, cellular membranes are imperfectly formed which causes increased susceptibility to various insults and increased permeability. Low-density lipoproteins (LDL) transport cholesterol mainly as cholesteryl linoleate and supply EFA to tissue. A relative deficiency of EFA (i.e. a high ratio in the body of non-EFA such as long-chain saturated fatty acids to EFA) causes an increase in plasma cholesterol. EFAs cause decreased aggregation of platelets. Atherosclerosis is not caused by increased aggregation of platelets, and can be prevalent in a population in which coronary thrombosis is rare.

Arteriosclerosis↗