PubMed Health⌕ Search

Biomedical subjects

M Pascaud

Publications and source records attributed to M Pascaud.

At least 19 recordsLinked to original sources
PubMed1996

Effects of dietary gamma-linolenic acid on the tissue phospholipid fatty acid composition and the synthesis of eicosanoids in rats.

The purpose of this study was to evaluate the effects of different doses of dietary gamma-linolenic acid (GLA) on the tissue phospholipid fatty acid composition and the synthesis of eicosanoids in growing rats. The supplementation with different oils rich in GLA (borage oil, evening primrose oil, or Spirulina oil) and poor in n-3 polyunsaturated fatty acids or biomass of Spirulina results in a significant dose-related increase of GLA and dihomo-GLA in liver, erythrocyte, and aorta phospholipids in rats fed during 6 weeks different levels of GLA. The arachidonic acid (AA)/dihomo-GLA ratios decreased with increasing intake of dietary GLA, but the AA proportions remained stable. The dietary administration of GLA increased the in vitro production by the aorta of prostaglandin E1 derived from dihomo-GLA, but did not significantly influence the production of prostaglandin E2 derived from AA by the aorta and the thromboxane B2 level in serum.

Alprostadil↗
PubMed1993

Modulation of rat and human lymphocyte function by n-6 and n-3 polyunsaturated fatty acids and acetylsalicylic acid.

The effects of in vitro additions of between 10 and 100 microM n-6 and n-3 polyunsaturated fatty acids were examined on the proliferation of stimulated T lymphocytes in culture. For both phytohemagglutinin-induced human blood lymphocytes and concanavalin-A-induced rat splenic lymphocytes, the largest inhibitory effects were obtained with 22:4 n-6 and 22:6 n-3, and to a lesser extent with 20:5 n-3. Arachidonic acid 20:4 n-6, the main eicosanoid precursor, was not inhibitory, it even stimulated rat lymphocyte proliferation. Acetylsalicylic acid stimulated both human and rat lymphocyte proliferation. The effects of moderate decreases in the dietary n-6/n-3 ratio by either linseed oil or fish oil maximum eicosapentaenoic acid (MaxEPA) were determined on rat lymphocyte proliferation and natural killer (NK) cell activity in vitro. Dietary changes did not affect mitogen-induced lymphocyte proliferation in vitro, but proliferation of unstimulated lymphocytes was significantly lowered (4-fold) with the n-3-enriched diets. Dietary fish oil but not linseed oil significantly increased the NK cell activity of rat splenic lymphocytes. The n-3-enriched diets, especially the fish oil diets, reduced the stimulatory effect of in vitro added acetylsalicylic acid (aspirin) on lymphocyte proliferation.

Animals↗
PubMed1992

Hydroxymethylthiobutanoic acid spares methionine from catabolism in the chick.

Two groups of chicks were fed, until they were 3 weeks old, diets supplemented with either DL-methionine (MET) or DL-2-hydroxy-4-methylthiobutanoic acid (HMB). Oxidation to CO2 and uric catabolism of intraperitoneally injected L-[1-14C]MET and DL-[1-14C]HMB were studied comparatively for 8 h. HMB supplementation spares available MET from both oxidative and uric catabolism.

Animals↗
PubMed1990

Effects of moderate dietary supplementations with n-3 fatty acids on macrophage and lymphocyte phospholipids and macrophage eicosanoid synthesis in the rat.

The effects of a moderate dietary intake of n-3 polyunsaturated fatty acids were determined on the eicosanoid synthesis by rat peritoneal macrophages: the availability of arachidonic acid (20:4 (n-6)) and eicosapentaenoic acid (20:5 (n-3] in the membrane phospholipids of peritoneal macrophages and splenic lymphocytes and the synthesis of the main eicosanoids were evaluated in parallel. The n-6/n-3 ratio was decreased from 13.5 in the control diet rich in 18:2(n-6) to about 2 by an addition of either linseed oil providing 18:3(n-3) (linseed oil diet) or fish oil providing 20:5(n-3) and 22:6(n-3) (fish oil diet). The dietary linoleic acid content was at least 3.5% of energy in each diet. In peritoneal macrophage and splenic lymphocyte membrane phospholipids, arachidonic acid content was significantly decreased with the linseed oil and fish oil diets. 20:5(n-3) content was significantly raised up in the linseed oil group (3-fold in macrophage phospholipids) and more strikely in the fish oil group (7-fold). In response to a stimulation by the calcium ionophore A23187, peritoneal macrophages released 6-ketoPGF1 alpha, TXB2, PGE2 and LTB4 and/or 5, but no or few peptidoleukotrienes. The linseed oil did not affect significantly the synthesis of these eicosanoids, except for LTB5, which was increased 2-fold. In contrast, the fish oil diet led to significant decreases in the productions of 6-ketoPGF1 alpha and PGE2 (-50%) and LTB4 (-40%) and to a 10-fold increase in the release of LTB5. TXB2 was also decreased (-35%), but not significantly. These results and the parallel evolutions of the two ratios 20:4(n-6)/20:5(n-3) and LTB4/LTB5 showed that eicosanoid synthesis is greatly dependent on the relative availability of the two substrates in competition.

6-Ketoprostaglandin F1 alpha↗
PubMed1990

Plasma and tissue-free amino acids in the developing chick.

The free amino acids of the plasma and pectoral muscle, liver and brain cytosolic S105 supernatant obtained from 2- and 3-week-old fasted chicks, were analyzed by HPLC after deproteinization by ultrafiltration. Protein-bound amino acids were analyzed in parallel studies. A clear relationship between the free and bound tissue amino acids was apparent. Only for the gluconeogenic amino acids a close correlation was evident between the plasma and the muscle free amino acids. A relatively steady composition of the free amino acids is established early in the tissues, but in the plasma it changes significantly with age.

Aging↗
PubMed1989

In vivo 14C isotopic evaluation of amino acid oxidative catabolism in the growing chick. I. Fast respiratory 14CO2 and acetyl-CoA renewal.

A single dose of [1-14C] or [U-14C]glycine or L-[1-14C] or [U-14C]valine was injected intraperitoneally into 1- and 3-week-old chicks. Continuous automatic determination of respiratory 14CO2 and determination of 14C in excreta and uric acid were carried out for 8 h. Computer-aided analysis of the kinetics of respiratory 14CO2 demonstrated two exponentially decreasing components, 'fast 14CO2' and slow 14CO2'. Fast 14CO2 production represents the immediate oxidation and/or decarboxylation of the 14C-labeled amino acid. The half-lives differed according to the nature of the 14C-labeled amino acid but not to the age of the chick. The size of the acetyl-CoA pool labeled by [14C]glycine was between 10 and 15 mmol/100 g of chick. Metabolic partition of a circulating plasma free amino acid between oxidation and retention could be quantified by an isotopic index.

Acetyl Coenzyme A↗
PubMed1989

In vivo 14C isotopic evaluation of amino acid oxidative catabolism in the growing chick. II. Slow respiratory 14CO2 and protein renewal.

Analysis of the respiratory 14CO2 of growing chicks injected intraperitoneally with [1-14C] or [U-14C]glycine or valine has shown the presence of a delayed 'slow 14CO2' exponential component. The half-lives, about 3 h, are independent of the nature of the amino acid and of the age (1-3 weeks) of the animal. As supported by investigations in cycloheximide-treated chicks of the oxidative catabolism of glycine, valine and acetate, slow 14CO2 is significantly associated with the degradation of short-lived proteins.

Acetates↗
PubMed1987

Hydrochloric acid hydrolysis of proteins and determination of tryptophan by reversed-phase high-performance liquid chromatography.

A simple method was developed for determination of tryptophan in proteins. Hydrolysis is achieved under reducing conditions, in 6 N hydrochloric acid containing 0.4% beta-mercaptoethanol, at 110 degrees C for 24 h. The phenylthiocarbamyl derivatives of the amino acids are separated by reversed-phase high-performance liquid chromatography, without any by-product interference. The recovery of tryptophan is complete. However, the method does not allow the determination of tryptophan in carbohydrate-rich biological samples.

Amino Acids↗
PubMed1980

[Essential fatty acids and animal development].

With the exception of some cell strains in culture, the animal cells need w6 linoleic acid and its superior polyinsaturated derivatives for their structural growth and their multiplication. Deficiency of linoleic acid leads to growth failure, organic fraility and death of the animal. Involvement of the prostaglandins is not demonstrated. w3 linolenic acid and its superior derivatives are essential for the development of the sea animals. Linolenic acid appears also essential for the mammal nervous cells at the step of cell division anterior to myelinisation. Disponibility of the essential fatty acids for the mammal fetus is principaly assumed by the mother liver of which the metabolic activity in conversion of the precursors to superior derivatives and synthesis of transport lipoproteins is increased. Involvement of the polyunsatured acids in satisfying the structural and energetic needs of the developing animal concerns predominantly--but not exclusively--the cell membranes structure and fluidity and activity of the functional proteins (enzymes, mitochondrial oxydophosphorylation).

Animals↗
PubMed1977

Assimilation of 14C-linoleic acid by the rat fetus.

Following ingestion, by the 20-day pregnant mother, of (1-14C)linoleic acid, the retention and distribution of 14C are determined in th fetus, placenta and mother, after 1, 3 and 6 h. Comparison of the specific activities of linoleic and arachidonic acids in the maternal plasma, liver and placenta, and the fetal plasma, liver and carcass leads to the conclusion of a selective materno-fetal transfer of arachidonic acid, relative to linoleic acid, through the placenta.

Animals↗