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Biomedical subjects

P Rondot

Publications and source records attributed to P Rondot.

At least 91 records · Page 5Linked to original sources
PubMed1981

[Pseudo-tumoral neurological affections in adults localized to the middle and posterior sections of base of skull (author's transl)].

Many neurological affections of the middle and posterior sections of base of skull may simulate tumors. Vascular disorders include diabetic lesions, diffuse cerebral vascularitis, vascular malformations, posterior fossa angioma, telangiectasis or cavernous hemangioma, and basilar artery aneurysms. Degenerative or deficiency nervous system affections may also simulate tumors, as well as bone or nerve malformations, such as erosions due to basilar artery compression. Arnold-Chiaris malformation, aqueduct stenosis, or an empty sella turcica.

Adult↗
PubMed1980

Loss of topographic memory with learning deficits.

A case is reported in which a patient with a vascular accident involving the posterior portion of the minor hemisphere presented a topographic memory loss and also deficits in his ability to learn certain types of new material. The study of this case has led us to re-examine spatial functioning in light of both human and animal research. Based on clinical and experimental evidence we have proposed that a unitary interpretation can account for the various spatial deficits associated with posterior righ hemisphere lesions. We have also suggested that the establishment of a spatial map for orientation probably depends not only on posterior right hemisphere structures but also may require the participation of structures which are more specifically concerned with learning and memory, such as the hippocampus or at least the connections between the hippocampus and these structures.

Cerebrovascular Disorders↗
PubMed1980

Inhibition and synchronisation of tremor induced by a muscle twitch.

The effects of a muscle twitch on the tremor of the extensor indicis muscle and of the tibial anterior muscle have been recorded in 14 patients with essential tremor and in 10 patients with Parkinson's disease. The muscle twitch evoked by the electrical stimulation of the motor nerve inhibits the tremor and synchronises it. The mean duration of the inhibition is 92.1 +/- 6.8 ms for essential tremor and 183.0 +/- 16.8 ms for Parkinsonian tremor. This inhibitory phase lasts longer when the muscle twitch is induced during the second half of the Parkinsonian tremor cycle. The effects of voluntary contraction and of unloading suggest that inhibition and resetting of the tremor can be attributed to the autogenic mechanism induced by Ib fibres discharges. The presence of a rhythmic inhibition in the cycle of Parkinsonian tremor accounts for the longer duration of the inhibitory phase. In practice, these techniques aid the diagnosis of tremor in these two conditions, for example they assist the identification of low frequency essential tremor and of postural tremor in Parkinson's disease.

Aged↗
PubMed1980

[Diffuse corticoid-sensitive cerebral arteritis (author's transl)].

Three cases of cerebral vascularitis are reported. This affection does not occur frequently and is often unrecognized. It can be isolated or associated with disease such as sarcoidosis, Behcet's disease, or collagen disorders (lupus erythematosus, mixed connective tissue diseases). Diagnosis is made from the evolution with transient remission, the inflammatory nature of the CSF, and the presence of segmentary narrowing on arteriography. In case of doubt an exploratory operation with biopsy is necessary. The most likely etiology is an auto-immune disturbance, and cortico-therapy has greatly improved the prognosis.

Adrenal Cortex Hormones↗
PubMed1979

[Abnormal movements induced by psychotropic drugs].

The abnormal movements produced by the psychotropic drugs are related to various physiopathological mechanisms: -- dopaminergic receptors blockage provokes neuroleptic parkinsoniam tremor; -- neuroleptic-induced tardive dyskinesia is similar to 1. Dopa abnormal movements; tardive dyskinesia is due to denervation induced hypersensitivity of the dopamine receptor; the 1. Dopa dyskinesia is probably related to altered responsiveness of these receptors due to an increase in dopaminergic receptor sensitivity; -- antidepressant drugs, particularly lithium, provoke tremor, alleviated by beta blockage; it is probably caused by an abnormal sensitivity of the beta noradrenergic receptors.

Chorea↗
PubMed1978

Muscle reaction to passive shortening in normal man.

We have studied in 32 healthy subjects the EMG activity of biceps and triceps brachii, wrist flexors and wrist extensors, triceps surae and tibialis anterior, sterno-cleido-mastoideus (SCM) and splenius, during their passive shortening. A shortening reaction was observed more frequently in wrist extensors, SCM and tibialis anterior than in biceps and triceps brachii. The response appeared only when the joint reached a specific angle regardless of the starting point or the speed used to reach this position. During a muscle ischaemia which abolished the tendon reflex the reaction was not modified. During a joint ischaemia produced distal to the examined muscle its amplitude was strongly reduced. Our results support the hypothesis that joint receptors could play a role in its origin, perhaps through a long-loop reflex.

Adult↗
PubMed1977

Visuomotor ataxia.

Visuomotor ataxia is a disorder of movement performed under visual control. It can occur in the absence of disturbance of ocular fixation and in the absence of spatial agnosia. This disorder may extend over the whole visual field or it may be localized to one visual half-field, right or left. It may involve both hands or one hand only, so that visuomotor ataxia may be divided into: (1) Unilateral visuomotor ataxia, localized to a single field. In this case it may affect both hands or a single hand. It is direct when the hand is ataxic in the ipsilateral visual field and it is crossed when the hand is ataxic in the contralateral visual field; (2) Bilateral visuomotor ataxia, involving the whole visual field. Each hand may be ataxic only in the contralateral visual field, that is, bilateral crossed visuomotor ataxia; or in the ipsilateral field when it is called bilateral direct visuomotor ataxia. The observed clinical variations which are described here imply the existence of both direct and crossed visuomotor connections, the latter probably crossing the corpus callosum in the splenium.

Adult↗
PubMed1977

Reciprocal continuous inhibition in rigidity of Parkinsonism.

A reciprocal continuous inhibition by flexor on extensor muscles was proved during Parkinsonian rigidity. Extensor motoneurone excitability was tested by Hoffmann's reflex and flexor activity was altered by lidocaine anaesthesia of the peroneal nerve (PN). During PN anaesthetic block, a gradual increase of Hoffmann's reflex was noted. It was statistically significant at the 15th minute after lidocaine injection, and was maximum at the 30th minute. The reciprocal inhibition was considerable in 16 patients with Parkinsonism, as recorded before treatment. In normal subjects, it was small and non-significant. After one month's treatment with L-dopa at the usual therapeutic dose, this reciprocal inhibition greatly decreased in the same patients. The origin of this reciprocal continuous inhibition is discussed.

Adult↗
PubMed1977

[Eaton-Lambert myasthenic syndrome: clinical, electrophysiologic, histological and ultrastructural study].

In this case, showing the classical features of the Eaton-Lambert myasthenic syndrome, the neuromuscular symptoms appeared 21 months before the bronchial carcinoma was diagnosed. The electrophysiological study demonstrated, beside the marked potentiation under repetitive nerve stimulation at 30 c/sec., some modifications of distal latency, specially after administration of Edrophonium chloride. The muscle biopsy showed changes secondary to a peripheral motor nerve involvement; electronmicroscopic study of the motor end-plates revealed a highly developped subneural apparatus. Long-run treatment by guanidine hydrochloride determined haematologic and renal toxic manifestations. Prednisolone was for a time active on the myasthenic syndrome.

Action Potentials↗
PubMed1975

[Optic ataxia localised in the left side of both 2 left homonymous visual hemifields].

Ocular ataxia localised to the left limbs on the left homonymous visual hemifields occurred after section of the right parieto-occipital junction zone performed to remove an intraventricular tumour. Since the right upper limb was unaffected, it must be presumed that, in man, there are two types of occipito-frontal connections, direct and crossed.

Adenocarcinoma↗