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Biomedical subjects

M A Fessard

Publications and source records attributed to M A Fessard.

7 recordsLinked to original sources
PubMed1977

[Variation in the number and size of myelinated nerve fibers regenerated after repeated localized freezing of the sciatic nerve of rats].

The number and size of myelinated fibres have been determined in the nerve to medial head of the gastrocnemius muscle of Rats in which the sciatic nerve had been frozen locally 1 to 5 times at monthly intervals. The contralateral nerve was used as a control. When the measurements were made one month after the last freezing, the number of fibres increased progressively until the 3rd freezing, reaching about 220% of the normal value. No higher values were observed after 4 or 5 freezings. The mean diameter of fibres decreased with the number of operations. When the measurements were made 3, 6, 12 or 18 months after the 3rd freezing, the number of fibres decreased by about 30% between the 1st and the 3rd month and then stabilized. The mean diameter of fibres increased progressively. However, at the 18th month, the size of the myelinated fibres had not reached the normal value.

Animals↗
PubMed1975

[Effect of metabolism on the electrical and mechanical activities of the frog atrium].

Due to glycolysis, anaerobic ATP supports normal electrical activity and allows only a reduced but sustained mechanical activity; however, frog myocardium metabolism is mainly aerobic dependent. Krebs cycle provides ATP for both mechanical and electrical acitivites even when glycolysis is inhibited. The close correlation between amplitude of contraction and metabolic state suggests that ATP is a limiting factor of mechanical activity even in normal conditions. Therefore it is necessary to use oxygen and to add pyruvate which partly compensate for the decrease of mechanical activity observed during the occurrence of hypodynamic state. Moreover equilibrating the oncotic pressure prevents hypodynamia and considerably improves the experimental conditions.

Action Potentials↗
PubMed1975

[Differentiation factors of active zones of presynaptic membranes].

The differentiation of the subsynaptic areas depends very probably on a local influence exerted by the axon terminals; but conversely, as suggested by obervations on the development of neuromuscular junctions of "fast" and "slow" muscle fibres in Anura, complementing the results of previous degeneration experiments on frog muscles, the subsynaptic areas might intervene in the differentiation of "active zones" of presynaptic membranes.

Animals↗
PubMed1975

[Modes of appearance of giant spontaneous potentials induced by vinblastine on the isolated preparation of frog muscle].

Vinblastine induces reversible changes of the spontaneous release of ACh at the fro,neuromuscular junction characterized by the appearance of "giant" potentials. These large potentials occur soon after soaking the muscle in Vinblastine and are not consecutive to a large increase of the spontaneous release. They seem to serive from the release of big packets of ACh which could be elaborated from preexistent quantal units.

Acetylcholine↗