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Biomedical subjects

D Marlot

Publications and source records attributed to D Marlot.

43 records · Page 3Linked to original sources
PubMed1978

Myelinated nerve fiber supply and muscle spindles in the respiratory muscles of cat: quantitative study.

The present study was undertaken to provide quantitative data on the myelinated fibers of the phrenic and intercostal nerves and the number of spindles in the main respiratory muscles of the cat. The myelinated component of the phrenic and intercostal nerves was studied in the cat. Histograms of sequency distributions as a function of nerve fiber diameter were established for normal nerves. Certain nerves were then examined 35 to 40 days after excision of the dorsal spinal ganglia. The muscle spindles of the corresponding muscles were counted and localized, and, on the basis of several morphological criteria, were classified with those usually described in the interosseous muscles. The study of the nerves, as that of the spindles, demonstrates clear differences of proprioceptive innervation among the respirator muscles. The lateral part of the diaphragm and the Triangularis sterni have practically no spindles. The external muscles of the first thoracic spaces are very rich in spindles. Respiratory muscles can be ranged in an almost continuous manner between these two extremes.

Animals↗
PubMed1975

[Effects of graded distensions of the thoracic esophagus on spontaneous activity of the diaphragm in the cat and rabbit].

In 20 Cats and 10 Rabbits, under Nembutal anaesthesia, the thoracic oesophagus has been distended at different levels by means of a small latex balloon. We have observed an inhibition of the electrical activity of the crura during the distensions of the lower oesophagus. This modification disappears after bivagotomy. Therefore it is probably mediated by a vagal reflex. The long duration of the observed inhibition suggests that the slow adaptating receptors lying at the level of the oesophago-gastric junction are involved.

Action Potentials↗
PubMedDate not supplied

[The Hoffmann reflex in the normal new-borns. Post-natal evolution of the conduction velocity of the alpha motor and the Ia sensitive fibres of the ulnar nerve (author's transl)].

The conduction velocities of the alpha motor fibres and the IA sensitive fibres of the ulnar nerve have been studied in a group of full term newborn babies and during the neonatal period. At birth the average conduction velocity of the alpha motor fibres is 25,7 m/sec (sigma = to 2,4 m/sec) that of the IA afferent fibres is 35 m/sec (sigma = to 3,2 m/sec). The post natal evolution of the conduction velocity as a function of age has been established for both types of fibres. The time required for nervous conduction between the olecranon process and the wrist diminishes clearly in the course of the first two years because of a discordance between the augmentations of the length and of the diameter of the nerve fibers. The evolution of this conduction time as a function of the age and of the length of the forearm, has been established for the period between birth and the age of six years. The Hoffmann reflex in the inferior limb is present in all infants at birth; its latency is 14,2 msec; the ratio R = to Hmax/Mmax x 100 = to 55,75 p. 100 is identical to that found in the adult. A Hoffmann reflex exists in 66 p. 100 of the population studied in the ulnar nerve. Its latency is 11,1 msec; R = to Hmax/Mmax is equal to 30 p. 100. This reflex disappears progressively during the development.

Age Factors↗
PubMedDate not supplied

[Structure-activity relationship of a new family of calcium antagonist molecules derived from monosaccharides].

The Ca++ antagonist effects of new drugs derived from monosaccharides were tested in the rat duodenal muscle preparation in vitro. The structure-activity relationship shows that: 1. The monoacetonide products (nR-O-MAG and nR-S-MAG) with alkyl chain from 8 to 9 C atoms induce a maximal reduction of muscular tonus and contraction. 2. The inhibitory effect rapidly decreases when the alkyl chain has a number of C atoms smaller than 7 or larger than 9. 3. The diacetonide (DAG) and acetonide (G) products induce an inhibition of less extent. 4. The Ca++ antagonist effect is very slightly changed by the type of heteroatom (O or S) linking the alkyl chain to the monosaccharide. 5. The type of monosaccharide affects the Ca++ antagonist activity.

Animals↗
PubMedDate not supplied

[Effects of the monosaccharide derivative 8RN-DAGal on the putative P-type calcium channel expressed in Xenopus oocytes].

P-type calcium channels are expressed in Xenopus oocytes after injection of rat cerebellar mRNA. The FTX and omega-Aga-IVa toxins extracted from Agelenopsis aperta venom are known to inhibit the activity of this channel. The present results demonstrate that 8RN-DAGal is also a antagonist of P-type calcium channels. The inhibition of the current, obtained with Ba2+, as charge carrier, is voltage dependent.

Animals↗