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Biomedical subjects

J Belin

Publications and source records attributed to J Belin.

At least 37 records · Page 2Linked to original sources
PubMed1980

Incubation of exogenous fatty acids with lymphocytes. Changes in fatty acid composition and effects on the rotational relaxation time of 1,6-diphenyl-1,3,5-hexatriene.

Lymphocytes were incubated with various long chain fatty acids bound to albumin. Incubation for 20 h with unsaturated fatty acids resulted in uptake into the neutral lipids and phospholipids. The addition of concanavalin A enhanced the uptake. With the unsaturated fatty acids the rotational relaxation time of 1,6-diphenyl-1,3,5-hexatriene (DPH) was decreased, while with saturated fatty acids there was only a very small effect. The effect on the rotational relaxation times with unsaturated fatty acids was found to be due to the formation of lipid droplets in the cytoplasm. When plasma membrane free of lipid droplets was prepared, there was no effect on the rotational relaxation time despite incorporation of either linoleate or palmitate into the membrane phospholipids. Phospholipid liposomes prepared from plasma membranes obtained from cells which had been cultured with and without exogenous linoleate gave identical rotational relaxation times regardless of the history of the cells from which they were obtained. It is concluded that although the fatty acid composition of lymphocyte plasma membrane can be modified by exogenous fatty acids, there is little effect on the degree of order of the membrane phospholipid fatty acyl chains as monitored by the effects on the rotational relaxation time of DPH.

Animals↗
PubMed1980

Levels of polyunsaturated fatty acids in lymphocytes of rats fed on diets varying in polyunsaturated fatty acid content.

1. When weanling rats were fed on a diet containing 0.1 g/kg of the diet as polyunsaturated fatty acid, it was found that after 2 weeks the level of linoleate in the lymphocyte lipids was 56 mg/g total fatty acids, as compared with a level of 138 mg/g in rats on a normal diet (P less than 0.005). Similar levels were obtained from rats which had been fed for up to 16 weeks on the deficient diet, but in a group killed after 28 weeks on the diet level was found to be only 20 mg/g total fatty acids. The arachidonate level was found to be approximately 220 mg/g total fatty acids, regardless of whether the rats were fed on a diet deficient in linoleate for up to 16 weeks or on a normal diet. In the group of rats killed after 28 weeks on the linoleate deficient diet, however, the arachidonate level was only 60 mg/g total fatty acids. 2. Percentage values for total fatty acids are given for plasma, adipose tissue, and lymphocytes for rats on normal and experimental diets. 3. Scatter diagrams of the levels of linoleate v. arachidonate in the lymphocyte total fatty acids showed no correlation between the levels of the two acids (r 0.05), but similar plots of linoleate and oleate levels showed an inverse correlation (r -0.68).

Adipose Tissue↗
PubMed1980

Levels of linoleate and arachidonate in red blood cells of healthy individuals and patients with multiple sclerosis.

The major fatty acids were measured in total lipid extracts of red blood cells from 23 control subjects and 31 patients with multiple sclerosis. In the healthy control subjects an inverse correlation (r = -0.83) was found between the percentages of linoleate and arachidonate. In the patients such an inverse correlation was not found. The results suggest an abnormality in the red blood cells of patients with multiple sclerosis specifically with regard to the regulation of the relative amounts of unsaturated fatty acids, and this has implications for the possible treatment of multiple sclerosis with dietary supplements.

Arachidonic Acids↗
PubMed1979

Inhibition of complement-dependent rosette formation after lymphocyte incubation with fatty acids.

Overnight incubation of lymphocytes with certain fatty acids bound to albumin has previously been shown to modify the fatty acid composition of cellular phosphoglycerides without impairing viability, and also to inhibit mitogen and antigen-induced lymphocyte transformation. In the present study, incubation of human lymphocytes with palmitic acid or with linoleic acid impaired their capacity to form complement-dependent rosettes but had no effect on either spontaneous rosette formation with sheep erythrocytes or Fc(gamma)-dependent rosette formation. With mouse lymphocytes, complement-dependent rosette formation was suppressed only following incubation with linoleic acid and there was no effect on Fc(gamma)-dependent rosette formation. Although the mechanism of these effects remains to be elucidated the results suggest that control of membrane lipid composition may modify the important in vivo immunological functions which involve complement receptors.

Animals↗
PubMed1977

Phytohaemagglutinin stimulation of human lymphocytes: effect of fatty acids on uridine uptake and phosphoglyceride fatty acid profile.

1. When added to cultures of human peripheral lymphocytes, saturated (palmitate, stearate, heptadecanoate) and unsaturated (oleate, linoleate, arachidonate) fatty acids bound to albumin at an acid-albumin ratio of 2:1, inhibited the phytohaemaegglutinin-stimulated uptake of [14C]-uridine. Uridine uptake in unstimulated cells was not affected by any of these fatty acids. 2. When saturated and unsaturated acids were present simultaneously in the incubation mixture the inhibit but relieved the inhibitory effects of both saturated and unsaturated fatty acids. 4. Stimulated and unstimulated cells incorporated exogenous fatty acids into membrane phosphoglycerides. Details of the fatty acid profiles are given. 5. Evidence is presented that the inhibition results, at least in part, from modification of phosphoglyceride fatty acid profile.

Dose-Response Relationship, Drug↗
PubMed1976

Relationship between plasma and lymphocyte linoleate in multiple sclerosis.

The linoleate level in total lipids was measured in lymphocytes from control subjects and patients with multiple sclerosis. A small but significant decrease was found in cases of multiple sclerosis. The percentage composition of lymphocyte fatty acids was determined in rats fed diets with various linoleate contents. There was a correlation between lymphocyte linoleate and plasma linoleate in both humans and rats.

Animals↗
PubMed1973

Double-blind trial of linoleate supplementation of the diet in multiple sclerosis.

Seventy-five patients in London and Belfast with multiple sclerosis were given daily supplements of a vegetable oil mixture containing either linoleate or oleate for two years in a double-blind control trial. Relapses tended to be less frequent and were significantly less severe and of shorter duration in the linoleate-supplemented group than in those receiving the oleate mixture, but clear evidence that treatment affected the overall rate of clinical deterioration was not obtained.

Adult↗
PubMed1971

Linoleate metabolism in multiple sclerosis.

(1) The levels of oleate and linoleate in the serum have been measured in 14 patients with multiple sclerosis (MS) and in 14 healthy subjects before, during and after a five day period when the normal diet was supplemented with linoleate. (2) In confirmation of earlier work the mean percentage of linoleate in the serum lipids of the MS patients was significantly lower (P < 0·01) than in the control subjects in the pre-supplementation period. The mean percentage of oleate showed an increase (P < 0·005) in the patients as compared with the controls while on their normal diets. (3) The period of linoleate feeding produced a considerable rise in the percentage of linoleate together with a fall in the percentage of oleate in both the controls and the MS patients. (4) When large amounts of linoleate, as present in sunflower seed oil, are ingested we have been unable to obtain evidence of a defect in absorption from the intestinal lumen.

Adult↗