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Biomedical subjects

M M Mahfouz

Publications and source records attributed to M M Mahfouz.

33 records · Page 2Linked to original sources
PubMed1984

Influence of dietary fats on ultrastructure and fatty acid. Composition of swine arterial tissue.

The effects of trans-fatty acid-rich and saturated acid-rich diets on the fatty acid composition and morphology of swine arterial tissues were studied. Three groups of two-month-old swine were fed either a basal diet or a basal diet containing 8.3% margarine or butter for 4 months. The most significant change observed in the fatty acid pattern was the accumulation of 18 : 2 omega 6 and the suppression of both 20 : 4 omega 6 and 22 : 4 omega 6 acids in the aortic tissues of swine fed either butter or margarine as compared to swine fed the basal diet. Also, omega 6 metabolites were significantly decreased in swine fed diets containing butter or margarine, as compared to those fed a basal diet. The group of swine which were fed either butter or margarine containing diets suffered a significant increase in intimal thickening of the coronary artery compared to those fed the basal diet. These thickened intima were characterized by the presence of modified smooth muscle cells, lipid containing cells, and degenerated cells without stainable lipids. However, there was no significant difference in the incidence and extent of intimal thickening of the coronary arteries between swine fed either of the two fat containing diets.

Animals↗
PubMed1982

Perturbation of the metabolism of essential fatty acids by dietary partially hydrogenated vegetable oil.

Rats were fed purified diets containing (i) partially hydrogenated soybean oil as source of isomeric octadecenoic acids, (ii) hydrogenated coconut oil as source of saturated fatty acids, and (iii) a low level of corn oil as low-fat control. All diets contained 18% of the linoleate requirement. Rat liver and heart phospholipids were analyzed by gas/liquid chromatography for fatty acids, and liver, microsomes were assayed for desaturase (acyl-CoA, hydrogen-donor: oxidoreductase, EC 1.14.99.5) activities. Products of desaturation reactions measured analytically provided more information with greater statistical significance than did the enzymatic assays. Rats fed isomeric octadecenoic acids showed more severe essential fatty acid deficiency than did saturated-fat and control groups. The suppression of linoleate metabolites was largely due to decreased delta 5 and delta 6 desaturase activities. At several levels of linoleate, the deficiency was more severe at the higher level of isomeric octadecenoic acids. Increasing the intake of linoleate to 7.5% of calories did not suppress deposition of isomeric unsaturated acids in tissue lipids.

Animals↗
PubMed1982

Inhibition of erythrocyte and plasma cholinesterase by 5-hydroxytryptamine.

The inhibition of human erythrocytes and plasma cholinesterase (ChE) by 5-hydroxytryptamine in vitro was studied. Constants characterising this inhibition, namely the inhibition rate for red blood cells RBCs (2.5 x 10(4) (mol/l)-1 min-1) and plasma ChE (1.08 x 10(4) (mol/l)-1 min-1) as well as the rate constant for spontaneous reactivation for RBCs (0.3 min-1) and plasma ChE (0.26 min-1) were calculated. The inhibition of RBCs and plasma ChE by 5-hydroxy-tryptamine was found to be of the competitive type.

Cholinesterase Inhibitors↗
PubMed1982

Effect of dietary trans fatty acids on cholinesterase and monoamine oxidase activities in different organs of rats.

The effect of trans fatty acids and essential fatty acid deficiency upon the activities of cholinesterase and monoamine oxidase in livers, hearts, brains and lungs of rats was studied. This study was performed using three groups of male albino rats. Two out of these three groups were fed essential fatty acid low diets containing 10% hydrogenated coconut oil (HCNO) or margarine stock (MS, partially hydrogenated soybean oil) while the third group was fed an adequate supply of essential fatty acids through a diet containing 10% corn oil (CO). In the group of rats fed HCNO the activities of cholinesterase and monoamine oxidase in their livers, hearts, brains and lungs were not significantly different from those of the control group fed CO. In the group of rats fed MS, the activity of cholinesterase was significantly decreased in the livers, hearts and brains, but not affected in the lungs, while the activity of monoamine oxidase was significantly decreased in the livers and hearts but not affected in the brains and lungs as compared to the control group fed CO. The levels of serum total lipids, total cholesterol and triglycerides were elevated in both groups of rats fed HCNO or MS than in the group fed CO, but this elevation was more highly significant in the group fed MS than in the group fed HCNO.

Animals↗
PubMed1980

Desaturation of isomeric trans-octadecenoic acids by rat liver microsomes.

Desaturation of twelve labeled positional isomers of trans-18 : 1 acids was investigated using enzymes of liver microsomes from essential-fatty-acid-deficient rats. Oleic acid was used as model for comparison and for optimizing the incubation conditions. Each positional isomer desaturated at a unique rate. The trans-6- and trans-13-octadecenoic acids gave mostly trans-6, cis-9- and cis-9,-trans-13-18 : 2 acids, respectively. The trans-5-isomer gave mostly cis-5, cis-9-18 : 2 acid. The trans-4-isomer gave a mixture of trans-4, cis-9- + cis-4, cis-9-18 : 2, trans-11-isomer gave cis-9, trans-11- + cis-9, cis-11-18 : 2; trans-12-isomer gave cis-9, trans-12- + cis-9, cis-12-18 : 2, and trans-14-isomer have cis-9,-trans-14- + cis-9, cis-14-18 : 2 acid. The trans-8-, trans-9-, and trans-10-isomers were not measurably desaturated. The site of desaturation of the trans-18 : 1 isomer was the 9-position, indicating action of delta 9 desaturase. Thus the isomeric trans-18 : 1 acids present in partially hydrogenated fats can be converted to cis, trans- or trans, cis- and cis, cis-18 : 2 isomers, and trans-18 : 1 isomers in food may have effects upon metabolic control because of the products derived from them.

Animals↗
PubMed1980

The effect of isomeric trans-18:1 acids on the desaturation of palmitic, linoleic and eicosa-8,11,14-trienoic acids by rat liver microsomes.

The inhibitory effects of the positional isomers of trans-18:1 acids on the desaturation of palmitic acid to palmitoleic (delta 9-desaturase), linoleic to gamma-linolenic (delta 6-desaturase) and eicosa-8,11,14-trienoic to arachidonic acid (delta 5-desaturase) were investigated. These trans-18:1 acids were found to be inhibitory for the microsomal delta 6-, delta 9- and delta 5-desaturases of rat liver. The position of the double bond in the trans-18:1 acids seems to be important in determining the degree of inhibition. At inhibitor/substrate ratio of 3:1, the delta 6-desaturase was most strongly inhibited by trans-delta 3, -delta 4, -delta 7 and -delta 15-18:1 isomers, whereas the delta 9-desaturase was most strongly inhibited by trans-delta3, -delta 5, -delta 7, -delta 10, -delta 12, -delta 13 and -delta 16 isomers. At inhibitor/substrate ratio of 6:1, the delta 5-desaturase was most strongly inhibited by delta 3-, delta 9-, delta 13- and delta 15-isomers. When 18:0 was added to the incubations of 16:0, 18:2 and 20:3 at the same I/S ratios used for the trans-18:1 acids, weak inhibition for delta 9- desaturase and no inhibition for delta 5- and delta 6-desaturases was observed.

8,11,14-Eicosatrienoic Acid↗