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Biomedical subjects

J M Peyronnard

Publications and source records attributed to J M Peyronnard.

30 records · Page 2Linked to original sources
PubMed1978

Polyneuropathy and folate deficiency.

We studied five patients (two men and three women, age between 58 and 76 years) with clinical and electrophysiological signs of polyneuropathy. Routine neurological, hematological, and gastroenterological studies as well as procedures to test fat malabsorption were performed. Folate determinations were done using both radioactive and Lactobacillus casei methods. Two patients displayed the signs of subacute combined degeneration of the spinal cord with polyneuropathy, while three had only signs of neuropathy. All had low serum folate concentration, long-standing gastrointestinal disease, and deficient folate intake. The D-xylose absorption test gave values in all patients, while none displayed the classical malabsorption syndrome. The patients had substantial improvement or recovered (according to clinical and electrophysiological measurements) after periods ranging from 9 to 39 months of folate therapy. Such acquired folate-responsive polyneuropathy has two principal characteristics: mixed sensorimotor with mainly sensory deficits, and involvement of one or both of the lower extremities much more extensively than the upper extremities.

Aged↗
PubMed1977

Electrophysiological and anatomical estimation of the number of motor units in the monkey extensor digitorum brevis muscle.

The electrophysiological technique used to estimate the number of motor units in man (McComas et al., 1971b) was tested in six monkeys. The number of motor units was estimated electrophysiologically in the extensor digitorum brevis (EDB) after deafferentation by excision of the lumbo-sacral dorsal root ganglia. In five animals, the mean number of motor units obtained by the technique was in good agreement with the number of alpha motor fibres counted in the nerve to EDB. However, the results obtained in one animal with partial denervation of the EDB indicate that the technique might be unreliable, at least at certain stages, after a peripheral nerve lesion.

Animals↗
PubMed1976

Myoclonus in familial restless legs syndrome.

Eighteen members of a family were affected over a span of five generations with the restless legs syndrome, transmitted as an autosomal dominant trait. Ten patients had myoclonus. The propositus, a 57-year-old man, suffered from repeated, intense, asymmetric flexion jerks of the lower extremities, alternating with fidgeting and friction movements of the legs; all occurred at night prior to sleep and severely interfering with it. The patient's movements ceased with the onset of stage 1 sleep, while in his brother, the motor activity persisted in stages 1 and 2 of sleep.

Humans↗
PubMed1976

Neonatal neuronal loss in rat superior cervical ganglia: retrograde effects on developing preganglionic axons and Schwann cells.

Beginning prenatally and during the first week after birth, there is normally a loss of axons in rat cervical sympathetic trunk. To test the hypothesis that this spontaneous axonal loss represents a natural process whereby an excessive number of immature preganglionic axons in the cervical sympathetic trunk adapts to the neuronal population in the superior cervical ganglion, the number of nerve cells in the superior cervical ganglion was reduced in newborn rats by administration of nerve growth factor antiserum, 6-hydroxy-dopamine or postganglionic anxotomy. Quantitative ultrastructural studies of these animals at later stages of development revealed that, with each method, the number of preganglionic axons and Schwann cells was reduced to nearly one-third of normal. These findings indicate that the superior cervical ganglion plays an important role in the development of the cervical sympathetic trunk. Removal of ganglionic cells causes a retrograde loss of preganglionic fibres. This process probably represents an exaggeration of the normal mechanism for elimination of redundant axons. Because the changes in axonal numbers are associated with similar reductions in the number of Schwann cells, it can also be concluded that postnatal Schwann cell proliferation is influenced by axonal populations.

Animals↗
PubMed1976

Nerve conduction studies and electromyography in Friedreich's ataxia.

Twenty-six of 50 patients were investigated with nerve conduction studies and electromyography using a standard protocol and were compared to the findings in 50 normal control subjects. Almost all cases of typical Friedreich's ataxia had absent sensory action potentials (SAP) in the digital (92%) or sural (96%) nerves. The others had markedly decreased S.A.P's. In these same patients motor conduction velocities were either normal or only slightly decreased. In the second, atypical group of 9 patients, the motor conduction velocities were considerably decreased. Because of the absence of sensory action potentials in Friedreich's ataxia, and that the absence was noted in our very mild cases, it is proposed that this measure be used to facilitate early diagnosis.

Action Potentials↗
PubMed1975

Schwann cell internuclear distances in developing rat unmyelinated nerve fibers.

The interrelation of Schwann cells in developing rat cervical sympathetic trunk was studied by measuring distances between consecutive Schwann cell nuclei in teased unmyelinated nerve fiber bundles (Remak fibers). From 300 to 400 inter-nuclear Schwann cell distances (INDs) were measured at ten days and 2, 4, 5, 6, 8, 12, and 16 weeks after birth. Median INDs increased from 54mum at ten days to reach adult values (90mum to 100mum) at 16 weeks of age. Mean axonal diameters measured in the contralateral cervical sympathetic trunk increased from 0.57mum to 0.69mum during the same period. Developmental changes in median INDs of Schwann cells correlated significantly with age but did not parallel increases in axonal diameter.

Aging↗
PubMedDate not supplied

Muscle reorganization after partial denervation and reinnervation.

The normal rat tibialis anterior (TA) muscle was found to be innervated by approximately 154 spinal motor cells of which 95 are alpha motoneurons. Most of these axons ran in the L4 root and connected with glycolytic type 2B muscle fibers. The L5 root supplied 8.4% to 14.7% of the motor axons of TA muscle and innervated type 1 and 2A muscle fibers rich in oxidative enzymes. Two months after section of the peroneal nerve, there was marked fiber-type grouping and compact rearrangement of the L4 and L5 motor units. After section of the L4 radicular nerve, the TA muscle remained atrophic with no evidence of fiber-type grouping until 3 months when the L4 regenerating axons reached the muscle. Similar results were obtained after ligation of the divided ends of the L4 radicular nerve, which delayed but did not prevent reinnervation. These data suggest that, after partial denervation, muscle reinnervation by collateral sprouting is a slowly developing process.

Animals↗
PubMedDate not supplied

Patient self-management of continuous subcutaneous insulin infusion.

Continuous subcutaneous insulin infusion (CSII) is one of the ways to control blood glucose for prolonged periods. This study was undertaken to establish the long-term feasibility and efficacy of CSII with patient self-management. Patients were instructed to maintain their calorie and carbohydrate intake. Basal infusion of insulin, representing 50% of the total pre-CSII dose, was supplemented by boluses of insulin based on carbohydrate intake for each meal. With this type of regimen, blood glucose and M-values were easily normalized during the physician-directed periods. This study demonstrated that near-normalization of blood glucose, M-values, and glycosylated hemoglobin was maintained after a 1 1/2-yr period of patient self-management. We attributed this successful management in part to the protocol used, in which boluses were related solely to carbohydrate intake while basal insulin was adjusted according to fasting blood glucose. The chronic normalization of blood glucose resulted in improvement of platelet function as witnessed by responsiveness to antiaggregating (PGE1) and aggregating (epinephrine) agents. An improvement was noticed in doppler measurement of ankle-arm blood pressure and a near-normalization of nerve latency and conductivity was observed.

Adult↗