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Biomedical subjects

C Meyrignac

Publications and source records attributed to C Meyrignac.

15 recordsLinked to original sources
PubMed1991

Muscle mitochondrial DNA in encephalomyopathy and ragged red fibres: a Southern blot analysis and literature review.

Various mitochondrial DNA abnormalities have been described in patients with encephalomyopathies. We performed Southern blot analysis of skeletal muscle mitochondrial DNA in nine adult patients with clinical features and ragged red fibres suggesting mitochondrial dysfunction. Two patients with encephalomyopathy and two with the MERRF syndrome (myoclonus epilepsy with ragged red fibres) had the normal PvuII restriction pattern of muscle mitochondrial DNA. In contrast, mitochondrial DNA deletion was observed in two of six patients with ophthalmoplegia. One suffered from typical Kearns-Sayre syndrome and the other from isolated external ophthalmoplegia. None of these patients had affected relatives. The detection of mitochondrial DNA deletion in external ophthalmoplegia and their site and size support previously reported data.

Blotting, Southern↗
PubMed1989

Focal myelin thickenings in a peripheral neuropathy associated with IgM monoclonal gammopathy.

Nerve biopsy in peripheral neuropathies associated with an IgM monoclonal gammopathy may occasionally display focal myelin thickenings. In a patient with such an IgM neuropathy, in whom an anti-myelin-associated glycoprotein (MAG) antibody activity was present in the serum, single-fiber preparations revealed 34% of internodes bearing myelin swellings. The morphometric, morphological and ultrastructural findings were reminiscent but not identical to those of the hereditary tomaculous neuropathy with liability to pressure palsies. Atypical features for tomacula included lack of spiralization of the redundant loops of myelin around the axons and their predominant external situation with regard to the myelin sheath. The frequent colocalization of myelin thickenings and the widening of myelin lamellae typical of IgM neuropathies, are highly suggestive of some pathogenetic link between the two abnormalities. The redundant loops of myelin in IgM neuropathies possibly result from a defect in the axon-myelin adhesion secondary to the binding of IgM on an epitope of MAG directly involved in cell-cell adhesion.

Aged↗
PubMed1988

[Papilledema caused by minocycline: apropos of a case].

Benign intracranial hypertension with papilloedema developed in a 18-year-old woman following Minocycline administration. Tetracycline therapy was prescribed for acne vulgaris. One month after the beginning of the treatment, she presented with headache, nausea and vomiting; there were no visual symptoms. Visual acuity and visual field were normal, fundus examination showed bilateral papilloedema. After Minocycline was discontinued and steroid therapy was administrated, symptoms rapidly resolved and papilloedema disappeared. Minocycline is known to penetrate into the central nervous system more effectively and to have a greater lipoid solubility than the other antibiotics of the same group. However the pathogenesis of benign intracranial hypertension after Minocycline therapy remains unknown.

Acne Vulgaris↗
PubMed1988

[Writer's cramp and left frontal meningioma].

A 55 year-old, right-handed, man developed a progressive writer's cramp spreading to a right hemidystonia. He had a left paramedian frontal meningioma. The association of an hemidystonia with contralateral lesions in the basal ganglia has been often reported. Its occurrence with a frontal lesion appear to be much less frequent. This association suggests a possible disorder of frontostriatal connections.

Dystonia↗
PubMed1987

Leucoencephalopathy with multinucleated giant cells containing human immune deficiency virus-like particles and multiple opportunistic cerebral infections in one patient with AIDS.

A 29-year-old homosexual male with AIDS presented with progressive encephalopathy and cytomegalovirus (CMV) pneumonia. Neuropathological examination revealed toxoplasma abscesses in corpus callosum, basal ganglia and cerebellar white matter; demyelinating foci in the parietal white matter, with microscopic changes typical of progressive multifocal leucoencephalopathy and intranuclear papovavirus inclusions in oligodendrocytes; and lesions of subacute encephalitis in the periventricular regions with large cells positive by immunostaining for CMV. Diffuse myelin loss was observed in the cerebral white matter. Multinucleated giant cells were numerous in the demyelinated areas, they were also observed in close relationship with papova, CMV and Toxoplasma lesions. Immunostaining of these cells was positive for histiocyte markers and negative with the leucocyte common antigen monoclonal antibody. Some of them contained virus-like particles measuring around 100 nm similar to human immune deficiency virus (HIV) as observed in human brain.

Acquired Immunodeficiency Syndrome↗
PubMed1986

[Non-dominant hemisphere syndrome as a result of a right thalamic infarct: an anatomoclinical case].

A 71 year old man had a massive left sensory deficit and hemiplegia, with left heminanopia, visual neglect and constructional apraxia. Moreover he experienced an extra-left arm and illusions of movements. 3 weeks later he suffered "thalamic" pain on left side; he died suddenly 6 weeks after the stroke. Post-mortem examination revealed: a) a right inner temporal and occipital infarction; b) a right thalamic infarction in the thalamogeniculate and paramedian territories; c) an infarction in the adjacent right internal capsule. Considering this case and pertinent literature on clinicopathological studies of right thalamic infarction, the authors suggest that a simultaneous ischaemia of thalamogeniculate and paramedian territories should be necessary to induce somatognosic and visuospatial disturbances.

Aged↗
PubMed1985

Amyotrophic lateral sclerosis presenting with respiratory insufficiency as the primary complaint. Clinicopathological study of a case.

A 59-year-old man presented with dyspnoea, hypersomnia followed by acute respiratory failure necessitating mechanical ventilation. There were no signs of cardiopulmonary disease and on the first few days, extubation was impossible. Further neurological evaluation supported the diagnosis of amyotrophic lateral sclerosis. The neuropathological examination corroborated this diagnosis, and showed a preponderance of lesions in the phrenic nuclei and axonal alterations associated with a fast evolution.

Amyotrophic Lateral Sclerosis↗
PubMed1978

[Study of hemodynamic effects of the methoxamine in 8 cases of obstructive cardiomyopathy with mitral valve insufficiency].

The haemodynamic effects of intravenous Methoxamine were studied in 8 patients with hypertrophic obstructive cardiomyopathy (HOCM) with mitral incompetence (group I) and 8 patients with mitral incompetence due to valvular, subvalvular or other causes (group II). In both groups the left ventricular end-diastolic pressure rose significantly without any great change in the end diastolic surface area: the ventricular distensibility is reduced in both cases. The mean capillary pressure, the V wave/mean capillary pressure ratio, and the degree of regurgitation of the two groups changed in opposite ways : in mitral incompetence due to varying causes (group II) the regurgitation increased, but in mitral incompetence due to HOCM (group I), it decreased. The left ventricular intracavitary gradient in HOCM tended to disappear under the effect of Methoxamine as the systolic aortic pressure approached the basal values recorded in the apical area.

Adult↗
PubMedDate not supplied

[Noradrenaline and cerebral aging].

The central functions of norepinephrine (NE) are a recent discovery: regulation of alertness and of the wakefulness-sleep cycle, maintenance of attention, memory and learning, cerebral plasticity and neuro-protection. The anatomical, histological, biochemical and physiological properties of the central noradrenergic system: extreme capacity for ramification and arborization; slow conduction, non-myelinized axons with extrasynaptic varicosities producing and releasing NE; frequency of co-transmission phenomena, and; neuromodulation with fiber effect responsible for improvement in the signal over background noise ratio and selection of significant stimuli form a true interface between the outside world and the central nervous system, notably for the neocortex in the context of the cognitive treatment of information. This central noradrenergic system is involved in the neurophysiology and the clinical features of cerebral aging (ideation-motor and cognitive function slowing down, loss of behavioral adjustment), neuro-degenerative disorders (SDAT, Parkinson's disease), certain aspects of depression and less obvious conditions (head injuries, sequelae of cerebrovascular accidents, sub-cortical dementia). The recent development of medications improving alertness (adrafinil, modafinil) with a pure central action and specifically noradrenergic, may contribute to an improvement in these multifactorial disorders.

Adaptation, Physiological↗