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S Metral

Publications and source records attributed to S Metral.

34 records · Page 2Linked to original sources
PubMed1975

[Influence of the electrical properties of electrodes (platinum wire) on the myoelectric signal].

The use, in electromyography, of platinum wire electrodes required a knowledge of the electrical characteristics of these electrodes in the frequency range of the myoelectric signal. For this purpose the impedance of these electrodes was measured by the "cercle pointe" method (Gougerot 1951) in conditions similar to those in use. These electrodes behave like the majority of metal electrodes. Their impedance in particular can be represented by a polarization capacity shunted by an ohmic resistance, in series with a resistance representing the electrolyte resistance. It is shown that, depending on the electrode area and the way they are used, these electrodes can detect the myoelectric signals more or less selectively.

Electrodes↗
PubMedDate not supplied

Dual type of facilitation at the neuromuscular junction of the frog.

End-plate potentials were recorded intracellularly at the frog neuromuscular junction. Facilitation produced by conditioning shocks applied to the motor nerve was studied in two different ways: using either low-frequency trains in Mg-blocked preparations or using brief high-frequency trains followed by a test shock of variable latency in D-tubocurarine-blocked preparations. In both cases, two distinctly different types of motor end-plates were observed. The first type showed a low quantum content and a marked facilitation without depression, while the second type showed a high quantum content, a poor facilitation, and a marked depression. The physiological significance of these findings is discussed.

Animals↗
PubMedDate not supplied

[Schwann cell pathology and axonal reduction in a case of congenital neuropathy with hypomyelinization].

A case of congenital dysmyelinating neuropathy is reported, in which computerised morphological analysis showed a prominent loss of fibers with large axons, in addition to overall thinness of myelin sheath. Ultrastructural examination showed aberrant formation of basal lamina and abnormal ensheathment by Schwann cells of both myelinated and unmyelinated fibers. Hypomyelination appears to be only one aspect of this neuropathy, in which axonal pathology plays a major role.

Axons↗