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Biomedical subjects

M Fontaine

Publications and source records attributed to M Fontaine.

At least 163 records · Page 9Linked to original sources

Studies on vitamin E and selenium deficiency in young pigs. I. Hematological and biochemical changes.

Pigs which were deficient in vitamin E and/or selenium had the following parameters weekly determined from six to 13 weeks of age: Packed cell volume, hemoglobin concentration, red cell and white cell counts, red cell indices, reticulocyte count, serum iron, serum total iron binding capacity, myeloid: erythroid ratio, serum glutamic-oxaloacetic transaminase and creatine phosphokinase activities and body weight. Except for the myeloid:erythroid ratio and serum creatine phosphokinase activity, these parameters were not found to be significantly affected by either vitamin E deficiency, selenium deficiency or deficiency of both. The myeloid:erythroid ratio was increased (p less than 0.01) in association with selenium deficiency, which tends to indicate decreased erythropoiesis but was not reflected in the peripheral red cell picture. Evidence of dyserythropoiesis was not found to be a significant feature in serial bone marrow aspiration biopsies of vitamin E and/or selenium deficient pigs. Even if the serum glutamic-oxaloacetic transaminase activities were not found to be significantly affected by either vitamin E deficiency, selenium deficiency or deficiency in both as compared to replete animals, a few animals, especially in the group deficient in both vitamin E and selenium, presented quite marked transient increases of serum glutamic-oxaloacetic transaminase activity which was interpreted to reflect the occurrence of acute episodes of hepatosis dietetica. Serum creatine phosphokinase activities were found to be increased in association with vitamin E deficiency (p less than 0.01), selenium deficiency (less than 0.05) and the interaction was also significant (p less than 0.01). It was concluded that the serum creatine phosphokinase activity increases reflect the occurrence of subclinical muscular dystrophy and that vitamin E and selenium deficiencies have marked additive effects in the induction of skeletal muscular dystrophy.

Animals↗

Studies on vitamin E and selenium deficiency in young pigs. II. The hydrogen peroxide hemolysis test and the measure of red cell lipid peroxides as indices of vitamin E and selenium status.

The usefulness of the hydrogen peroxide hemolysis test and the measure of red cell lipid peroxides as indices of vitamin E and selenium deficiency in swine has been evaluated. Results indicated that although the hydrogen peroxide hemolysis test may be of some indication of the vitamin E status, it is not a reliable index of vitamin E deficiency in swine, at least on an individual basis. In contrast, the measure of red cell lipid peroxides can be considered a reliable test for vitamin E deficiency in swine. The hydrogen peroxide hemolysis test and the red cell lipid peroxides were not significantly affected by selenium deficiency.

Animals↗

Studies on vitamin E and selenium deficiency in young pigs. III. Effect on kinetics of erythrocyte production and destruction.

The effect of vitamin E and/or selenium deficiency on the kinetics of erythrocyte production and destruction has been investigated in swine. The plasma iron turnover rate, 59Fe incorporation into newly formed red cells as well as the 51Cr apparent red cell half-life, were not found to be significantly affected by either vitamin E deficiency, selenium deficiency or deficiency of both, as compared to replete animals. The results of this study suggest that vitamin E is not a limiting factor for normal erythropoiesis in young growing pigs. Erythropoiesis appeared, however, to be slightly decreased in selenium deficient pigs and will need to be further investigated.

Animals↗

Studies on vitamin E and selenium deficiency in young pigs. IV. Effect on coagulation system.

An evaluation of the coagulation system has been conducted in vitamin E and/or selenium deficient swine. The partial thromboplastin time, plasma fibrinogen concentration, platelet lipid peroxides, as well as the fibrinogen/fibrin degradation products were not found to be significantly affected by either vitamin E deficiency, selenium deficiency, or deficiency of both. With selenium deficiency, the prothrombin time was shortened (p less than 0.05). The platelet count and platelet turnover were greatly decreased by both vitamin E (p less than 0.001) and selenium deficiency (p less than 0.005). Further-more, the survival of platelets labelled with 75Se-selenomethionine and the per cent isotope incorporated into platelets were reduced (p less than 0.05 and p less than 0.005) in association with vitamin E deficiency, but not with selenium deficiency. These results were interpreted as evidence of a platelet production defect and possibly a platelet function defect in vitamin E deficient animals. Selenium deficiency were also associated with decreased (p less than 0.05) survival of fibrinogen labelled with 75Se-selenomethionine and increased (p less than 0.05) turnover of fibrinogen. From these fibrinogen kinetic findings, it was considered that chronic low grade disseminated intravascular coagulation possibly occurs in selenium deficient animals, probably in relation to the development of hepatosis dietetica or widespread microvascular damage. However, other possibilities such as increased fibrinogenolysis in relation with hepatosis dietetica or an intrinsic fibrinogen defect due to selenium deficiency also need to be taken into consideration and have not been ruled out in the present study.

Animals↗

Evaluation of a rapid method of determination of plasma fibrinogen in swine.

An evaluation was made of a rapid semiautomated method for determining fibrinogen level in swine plasma. This method, referred to as thrombin time method or fibrometer method, is based on the principle that when thrombin is added to suitably diluted plasma, the time of clotting is linearly related to the fibrinogen concentration. The linear regression model for the standard curve prepared using swine plasma had an r value of 0.998. A comparison between the fibrometer and the Grannis methods done on 189 swine plasma samples showed good correlation between these two mehtods (r value 0.847). It was concluded that although the fibrometer method may not be as precise as the Grannis method, it would still be acceptable for clinical use in swine.

Animals↗

Localization of J-chain and interchain disulfide bonds in a human F(c)5mu-like fragment.

The inter H-H cysteinyl peptides and the localization of the J-chain were studied in a human F(c)5mu-like fragment. The latter was found to be built up by non-covalent association of molecular forms of 140 000, 95 000 and 70 000 dalton subunits. The trimeric, dimeric and monomeric forms were obtained from gradual reduction by dithiothreitol of the major component of 140 000 daltons, thus confirming the tetrameric nature of this subunit. The latter was found to result from the association of both components of the 70 000 dalton subunit, with the participation of the inter H-H subunit bridge. Structural analysis of the labelled peptides obtained by partial reduction and alkylation showed the presence of the intersubunit disulfide bridge and of the inter heavy-heavy chain bridge of the C-terminal region, and the absence of the heavy-heavy chain bridge of the hinge region. The sequence of these peptides is identical to the sequences of the corresponding peptides of normal mmu-chains. The J-chain, which was covalently linked to this F(c)5mu-like fragment, was found to be predominantly associated within the 95 000 dalton subunit. The results showed that the J-chain was linked in the protein as a "clasp" within a single subunit and not between two subunits.

Amino Acid Sequence↗

Septation deficiency and phosphilipid perturbation in Escherichia coli genetically constitutive for the beta oxidation pathway.

Mutants of Escherichia coli defective in the regulation of the fatty acids beta oxidation pathway show an ultrastructural deficiency in septum formation at high growth rate. Several independent pairs of parent and mutant strains have been analyzed biochemically. Each parent strain displays a well-defined pattern of cellular phospholipids, which varies with the growth conditions. High ratios of phosphatidylglycerol to cardiolipin characterize fast-growth conditions. None of the mutant strains, although they grow in mass nearly as rapidly as their respective parents, can reach these high ratios. The beta oxidation pathway regulatory mutation leads to an increased turnover of the glycerol moieties of these phospholipids in the inner as well as in the outer cell membrane.

Acetates↗

[Uveo-meningitis].

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Behcet Syndrome↗

[Effect of hypercapnia on the acid base states of the blood in the crab Carcinus maenas (L.) (Crustacea-Decapoda)].

When the crab Carcinus maenas respires in hypercapnic water, a respiratory acidosis occurs, which is progressively compensated by a rise of the blood bicarbonate concentration. The CO2 partial pressure in the blood increases in proportion to the change in ambient CO2 partial pressure. Therefore, the regulation of the acid-base status depends mainly on non-respiratory adjustments of the blood bicarbonate concentrations.

Acid-Base Equilibrium↗

[Control of the respiration in teleostean fish: respiratory reactions to abrupt changes in the oxygenation of the medium].

In the trench, carp and trout, an abrupt change in the partial pressure of ambient oxygen leads to a change in arterial oxygen tension which, within 1.5-2.6 seconds, elicits cardiac and ventilatory reactions. By their short latency, these responses may be explained as a modification of chemoreceptor activity, and resemble respiratory chremoreflexes of higher vertebrates.

Animals↗

[Contribution to the antigenic study of influenza viruses in animals. II.--Antibodies, antineuraminidase in horse: conditions of apparition and importance (author's transl)].

In the first part of this paper the conditions for a specific titration of antibodies against the neuraminidase (N) of each of the two horse virus subtypes are defined. The antigens used are: the H72Neq 1 recombining agent to measure the anti Neq1 antibodies and the A/Duck/Ukraine/63 strain for the anti Neq2 antibodies. The immunity response to neuraminidase appears after the natural disease; this response is studied in two foci, one due to a virus belonging to the A equi I subtype (Loire 73 strain), the other to a virus of the A equi 2 subtype (SHN 73 strain). The kinetics of apparition of anti N antibodies is mostly comparable to that of antihemagglutinin antibodies. The vaccination also induces an immunity response to neuraminidase: the intensity of this response gives an additional information for studying and checking the efficiency of equine i influenza vaccines.

Animals↗