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Biomedical subjects

D F Horrobin

Publications and source records attributed to D F Horrobin.

At least 145 records · Page 8Linked to original sources

Fatty acid composition of serum phospholipids in an elderly institutionalized Japanese population.

The fatty acid composition of serum phospholipids of 277 persons, aged 63-97 y (average 78 y), was measured. Subjects had been living independently in a facility with full food service for 1 y or more. Eleven saturated and unsaturated fatty acids were detected in all the subjects. Stearic acid (18:0) was positively (p = 0.028) and dihomo-gamma-linolenic acid (20:3 n-6) was negatively (p = 0.012) related to age. Arachidonic acid (20:4 n-6) tended to decline with age (p = 0.063). In addition, the oleic acid (18:1 n-9)/18:0 ratio decreased significantly with age (p = 0.024). 18:0 and total saturated fatty acids were lower, and linoleic acid (18:2 n-6) and 20:4 n-6 and n-6 fatty acids were higher in males than in females. These results suggest deficits in n-6 essential fatty acids as age advances, particularly in females.

8,11,14-Eicosatrienoic Acid↗

The effect of maternal supplementation with linoleic and gamma-linolenic acids on the fat composition and content of human milk: a placebo-controlled trial.

Total fat content and therefore total energy content and the content of essential fatty acids (EFAs) in milk are known to decline with prolonged breast feeding. In a placebo-controlled study a variety of evening primrose oil (Efamol) rich in linoleic and gamma-linolenic acids, or a matching placebo were given to 39 women for a period of 8 months starting between the 2nd and 6th months of lactation. Total fat and EFA contents of the milk declined in the placebo group but rose in the primrose oil supplemented group. A surprisingly high proportion of the supplemented dietary fatty acids could be accounted for by appearance in the milk. The milk composition can be readily manipulated by changing the fatty acid composition of the maternal diet.

Dietary Fats, Unsaturated↗

Levels of essential and other fatty acids in plasma and red cell phospholipids from normal controls and patients with atopic eczema.

Blood samples were collected from 48 atopic eczema patients and 33 normal subjects in Bristol, and from 434 normal individuals worldwide. In the plasma phospholipids in the atopic eczema patients, the concentrations of linoleic acid and the ratio of linoleic acid to its metabolites were significantly elevated as compared with both sets of controls. In the atopic eczema patients there were major abnormalities in the red cell phospholipids with saturated and monounsaturated fatty acids being significantly elevated and the concentrations of most essential fatty acids being significantly reduced. Patients with atopic eczema thus show abnormalities related both to desaturation of essential fatty acids and to their incorporation into red cell membranes.

Canada↗

The philosophical basis of peer review and the suppression of innovation.

Peer review can be performed successfully only if those involved have a clear idea as to its fundamental purpose. Most authors of articles on the subject assume that the purpose of peer review is quality control. This is an inadequate answer. The fundamental purpose of peer review in the biomedical sciences must be consistent with that of medicine itself, to cure sometimes, to relieve often, to comfort always. Peer review must therefore aim to facilitate the introduction into medicine of improved ways of curing, relieving, and comforting patients. The fulfillment of this aim requires both quality control and the encouragement of innovation. If an appropriate balance between the two is lost, then peer review will fail to fulfill its purpose.

Peer Review↗

Post-viral fatigue syndrome, viral infections in atopic eczema, and essential fatty acids.

Three clinical observations relating to viral infections are well-known but poorly understood. These are: the susceptibility of people with atopic eczema to viral infections; the occasional precipitation of an atopic syndrome by viral infections; the occurrence of a fatigue syndrome following viral infections. A unifying hypothesis is presented which explains these observations in terms of the interactions between viral infections and essential fatty acid (EFA) metabolism. Key elements of the hypothesis are the facts that interferon requires 6-desaturated EFAs in order to exert its anti-viral effects, that people with atopic eczema have low levels of 6-desaturated EFAs, and that viruses, as part of their attack strategy, may reduce the ability of cells to make 6-desaturated EFAs. The hypothesis has practical implications for the treatment of patients with viral infections.

Dermatitis, Atopic↗

Age-associated reduction of prostacyclin and thromboxane synthesis is inversely related to plasma cholesterol levels: modulation by dietary cholesterol supplementation.

Abnormalities of vasoactive eicosanoid synthesis with age are reported. We observed an age-associated reduction of vascular prostacyclin production and thrombin-stimulated thromboxane A2 production in blood. Amounts of production of these eicosanoids were inversely related to plasma cholesterol levels. However, there were no such relationships in rats supplemented with cholesterol. Dietary cholesterol supplementation induced a reduction of thromboxane A2/prostacyclin ratio regardless of age. These results suggest that age-associated changes of blood cholesterol levels are closely linked with vasoactive eicosanoid synthesis and that excessive consumption of cholesterol may induce a compensatory reaction by reducing the thromboxane A2/prostacyclin ratio.

6-Ketoprostaglandin F1 alpha↗

Essential-fatty-acid metabolites in plasma phospholipids in patients with ichthyosis vulgaris, acne vulgaris and psoriasis.

The concentration of essential fatty acids (EFAs) and their metabolites in plasma phospholipids were measured by gas chromatography in normal individuals, and in patients with ichthyosis vulgaris, acne vulgaris or psoriasis. In all three patient groups, concentrations of arachidonic acid (20:4 omega 6) and docosapentaenoic acid (22:5 omega 6) were significantly below those in controls, suggesting that these abnormalities may occur in many skin diseases. Concentrations of dihomogammalinolenic acid (20:3 omega 6) were low in ichthyosis, normal in acne and elevated in psoriasis. Thus ichthyosis, acne and psoriasis each had a characteristic pattern of EFA metabolites.

Acne Vulgaris↗

Stress modulates cholesterol-induced changes in plasma and liver fatty acid composition in rats fed n-6 fatty acid-rich oils.

The effects of dietary cholesterol (CH) and isolation stress on fatty acid compositions of plasma and liver cholesteryl ester and phospholipids were compared in growing rats fed an 18:2n-6 or an 18:3n-6 enriched semisynthetic diet for 2 weeks. Stress, CH-feeding, and dietary fats had no significant effects on plasma CH level, but CH-feeding alone elevated the liver CH concentrations. CH-feeding also modulated the liver polyunsaturated fatty acid compositions, i.e., increasing 18:2n-6 levels, and reducing 20:4n-6 levels, indicating an inhibition of the enzymes, delta-6 and delta-5-desaturases. The extent of these changes was less in rats fed 18:3n-6 than in those fed 18:2n-6. Stress, which alone had no significant effects on plasma and liver fatty acid compositions, attenuated the CH-induced changes of fatty acid levels.

Animals↗

Abnormal essential fatty acid metabolism in Darier's disease.

Fatty acid levels in plasma and erythrocyte cell membranes were determined in 13 Danish patients with Darier's disease and 21 Danish controls. Concentrations of the main dietary essential fatty acids, linoleic acid (18:2n-6) and alpha-linolenic acid (18:3n-3), were consistently modestly above normal; concentrations of the delta 6-desaturase metabolites of both linoleic and alpha-linolenic acids, however, were consistently and often significantly below normal. These results suggest that the capacity of the enzyme delta 6-desaturase activity is inadequate in patients with Darier's disease.

Adult↗

The grants game.

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Crime↗

[Effects of omega-3-fatty acids on the prostaglandin system in healthy probands].

Epidemiological comparisons of Greenland Eskimos and mainland Danes suggested that a diet rich in marine lipids mainly containing polyunsaturated fatty acids may be associated with a reduction in the incidence of occlusive vascular disease. Fish oils contain the Omega-3 polyunsaturated fatty acid eicosapentaenoate (timnodonic acid, EPA, 20:5n-3), which is incorporated into the platelet membrane after dietary intake instead of arachidonic acid (20:4n-6), the main substrate for prostaglandin synthesis. After incorporation of the fatty acids into the platelet membrane the overall effect of prostanoids with three double bonds derived from EPA proves to be less atherogenic. Since only TxA2 is a potent vasoconstrictor and platelet agonist whilst TxA3 is virtually biologically inert.

Adult↗

Essential fatty acids and the complications of diabetes mellitus.

In animals and humans with diabetes mellitus there is evidence that normal metabolism of essential fatty acids is impaired. The main dietary essential fatty acids, linoleic acid of the n-6 series and alpha-linolenic acid of the n-3 series, must both be 6-desaturated and converted to further metabolites if they are to exert all their desirable effects on the body. 6-desaturation is impaired in diabetes and a lack of adequate rates of formation of the 6-desaturated metabolites may be involved in the abnormalities in membrane function, in lipid metabolism and in haemostasis and the microcirculatory system which are seen in diabetes. Attempts to overcome the block by giving very large amounts of dietary linoleic acid, or to by-pass the block by giving 6-desaturated metabolites such as gamma-linolenic acid and eicosapentaenoic acid, have both given promising results.

Animals↗

Essential fatty acids in plasma phospholipids in schizophrenics.

Blood samples were taken from schizophrenics and control patients in three different centers. The phospholipids were extracted from plasma and their fatty acid composition analyzed. Similar and consistent differences between schizophrenics and controls were observed at all three centers. The n-6 essential fatty acid levels were significantly reduced, whereas n-3 essential fatty acids were elevated.

Adult↗