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P Clavelou

Publications and source records attributed to P Clavelou.

At least 37 records · Page 2Linked to original sources
PubMed2000

[Pseudomigraine with transient neurological signs and lymphocytic pleiocytosis].

We report the case of a 32-year-old man without previous medical history of migraine, who presented with severe headache and temporary focal neurological deficits. Lumbar puncture revealed aseptic lymphocytic pleiocytosis. The patient completly recovered within 2 months. This condition was suggestive of a transient syndrome of headache with neurologic deficits and CSF pleiocytosis. The main characteristics and the physiopathology of this uncommon disorder are discussed.

Adult↗
PubMed1999

[Superficial siderosis of the central nervous system].

We report five cases of superficial siderosis of the central nervous system. All patients developed progressive deafness and cerebellar ataxia associated with pyramidal tract signs or mental deterioration. The cerebrospinal fluid examinations usually revealed an elevated protein level, without other abnormalities. Magnetic resonance imaging typically showed a hypointense rim around the cerebral and cerebellar hemispheres, the brainstem and the spinal cord on T2-weighted images. A definite source of bleeding was only found in two patients. The literature on superficial siderosis is reviewed. The etiologies and the pathogenesis are discussed.

Adult↗
PubMed1998

Evidence that trigeminal brainstem interneurons form subpopulations to produce different forms of mastication in the rabbit.

To determine how trigeminal brainstem interneurons pattern different forms of rhythmical jaw movements, four types of motor patterns were induced by electrical stimulation within the cortical masticatory areas of rabbits. After these were recorded, animals were paralyzed and fictive motor output was recorded with an extracellular microelectrode in the trigeminal motor nucleus. A second electrode was used to record from interneurons within the lateral part of the parvocellular reticular formation (Rpc-alpha, n = 28) and gamma- subnucleus of the oral nucleus of the spinal trigeminal tract (NVspo-gamma, n = 68). Both of these areas contain many interneurons projecting to the trigeminal motor nucleus. The basic characteristics of the four movement types evoked before paralysis were similar to those seen after the neuromuscular blockade, although cycle duration was significantly decreased for all patterns. Interneurons showed three types of firing pattern: 54% were inactive, 42% were rhythmically active, and 4% had a tonic firing pattern. Neurons within the first two categories were intermingled in Rpc-alpha and NVspo-gamma: 48% of rhythmic neurons were active during one movement type, 35% were active during two, and 13% were active during three or four patterns. Most units fired during either the middle of the masseter burst or interburst phases during fictive movements evoked from the left caudal cortex. In contrast, there were no tendencies toward a preferred coupling of interneuron activity to any particular phase of the cycle during stimulation of other cortical sites. It was concluded that the premotoneurons that form the final commands to trigeminal motoneurons are organized into subpopulations according to movement pattern.

Animals↗
PubMed1998

Serum autoantibodies to neurofilament proteins in sporadic amyotrophic lateral sclerosis.

Anti-neurofilament (NF) autoantibodies were searched for by enzyme-linked immunosorbent assays (ELISA) in the serum from 85 sporadic amyotrophic lateral sclerosis (ALS) patients, 98 healthy controls and 79 patients with unrelated immunological diseases (Guillain-Barré syndrome, myasthenia gravis and multiple sclerosis). ELISA cutoff value was determined as mean control levels +2 SD and it corresponded to a specificity of 94%. Such high level antibodies were detected in 24.7% of ALS patients contrasting with 12.6% of neurological controls (P<0.05) and only 6.1% of healthy subjects (P<5.10[-4]). In ALS, anti-NF antibodies were significantly associated with a slow evolution, as measured by the mean time spent in the initial functional states. They did not relate with age, sex and clinical form. The predominant isotype of the anti-NF antibodies was IgM lambda by ELISA. In contrast to negative sera, indirect immunohistochemical studies demonstrated that most sera positive for anti-NF antibodies reacted with axons with predominant isotypes restricted to IgM lambda. By using Western blotting, small amounts of serum monoclonal IgM were found with a high frequency in anti-NF antibody-positive patients. These results suggest the possible involvement of anti-NF antibodies in an autoimmune process in a subgroup of ALS patients.

Aged↗
PubMed1997

Mutations in the X-linked form of Charcot-Marie-Tooth disease in the French population.

The present study reports eight additional mutations in the connexin32 gene associated with the X-linked form of Charcot-Marie-Tooth disease. One of these mutations was found twice in two apparently unrelated families. This form of the disease is demyelinating and dominant. However, patient selection for mutational screening should not be limited to these criteria since presentation can either be familial or sporadic, and some patients may be incorrectly classified as suffering from an 'axonal' form. These new mutations complete our previously published work on 12 other mutations and enable meaningful observation in a representative sample of the French population. Mutations are found in all regions of the gene. The most frequently observed mutations were those affecting arginines and mainly involved CpG sequences. Compared with other sources, some of the mutations were present at a higher frequency in the French population.

Adolescent↗
PubMed1997

Effects of chemical stimulation of masseter muscle nociceptors on trigeminal motoneuron and interneuron activities during fictive mastication in the rabbit.

An electrophysiological study was carried out in sixteen decerebrate and paralyzed New Zealand rabbits to determine how a bolus injection of a nociceptor stimulant (hypertonic saline, 5%) into the masseter muscle influences the activity of the trigeminal motor circuitry during fictive jaw movements. Hypodermic needles connected to a syringe held in a computer-controlled infusion pump were inserted into the anterior deep layer of either the right or the left masseter. Twenty-three infusions of 50, 70 or 80 microl saline were made in fourteen animals at constant rates over 1 min. Eight control infusions of normal saline (0.9%) were made in a subpopulation of five animals in an identical manner. Fictive jaw movements were evoked before and after the infusions by repetitive electrical stimulation of the corticobulbar tract. Effects were assessed by extracellular microelectrode recordings made from the digastric motoneuron pool and from putative last-order interneurons in the oral subnucleus of the spinal trigeminal tract and adjacent structures. In comparison with pre-infusion control cycles, nociceptor stimulation caused significant slowing of the rhythm and a reduction of the area of the digastric motoneuron bursts in the majority of the animals (12/14). The decrease in cycle frequency was due almost entirely to a lengthening of the time between the digastric bursts. Changes usually began 1-2 min after the infusion and returned to pre-infusion values within 10-15 min. No significant effects were seen when isotonic saline was applied. Recordings were obtained from nine interneurons, eight of which had low threshold mechanosensitive receptive fields. One neuron was, in addition, excited by pinch. Eight were not active in the absence of motor activity and this did not change when hypertonic saline was applied. However, once fictive movements began, all started to fire rhythmic bursts of spikes. In five cases, there was a significant post-infusion increase in spike frequency, and three showed decreases. Seven showed significant post-infusion changes in mean phase and/or concentration of their firing within the movement cycle. Changes in the preferred phase of interneuronal firing were significantly correlated to changes in the phase of offset of the digastric burst. The present results provide evidence that the stimulation of nociceptors in a muscle slows the frequency of rhythmical movements in the absence of sensory feedback. They confirm that infusions into one muscle affect the output of its antagonist. The results also suggest that neurons in the oral subnucleus of the spinal trigeminal tract and adjacent reticular formation appear to participate in programming these changes in motor output.

Animals↗
PubMed1997

A randomised clinical trial comparing interferon-alpha and intravenous immunoglobulin in polyneuropathy associated with monoclonal IgM. The IgM-associated Polyneuropathy Study Group.

OBJECTIVES: The polyneuropathy associated with a monoclonal IgM directed to the myelin associated glycoprotein (MAG) is a specific entity with a putative causal link between the IgM and the neuropathy. The small benefit offered by alkylating agents or plasma exchanges in these patients justifies the search for alternative treatments. METHODS: A 12 month multicentre, prospective, randomised, open clinical trial was carried out comparing intravenous immunoglobulin (IVIg; 2g/kg and then 1 g/kg every three weeks) and recombinant interferon-alpha (IFN-alpha; 3 MU/m2 subcutaneously three times weekly). The main end point was a clinical neuropathy disability score (CNDS) after six months of treatment. Twenty patients were enrolled; 10 were assigned to IVIg and 10 to IFN-alpha. RESULTS: At six months, one out of 10 patients treated with IVIg had a CNDS improvement of more than 20% whereas eight out of 10 patients treated with IFN-alpha had such an improvement (P=0.005). The mean CNDS worsened by 2.3 (SD 7.6) (8%) in the IVIg group whereas it improved by 7.5 (SD 11.1) (31%) in the IFN-alpha group (P=0.02). This improvement persisted after 12 months and was mainly related to an improvement of the sensory component (P=0.02) whereas the motor component was unchanged (P=0.39). Electrophysiological data did not show improvement of motor nerve conduction velocities whereas sensory nerve conduction velocities improved in the upper limbs. A decrease in the level of the monoclonal IgM was seen in two patients treated with IFN-alpha. At the end of the treatment, antibody activity to MAG was still detected in the serum of all patients. CONCLUSION: IVIg, as used in this study, did not improve patients with polyneuropathy and monoclonal IgM. By contrast, although its mechanism of action remains to be fully elucidated, IFN-alpha was effective in eight out of 10 patients at six months.

Adult↗
PubMed1996

[Neurogenic muscle hypertrophy: 3 cases].

Three cases of neurogenic muscular hypertrophy are reported. First case presented a hypertrophy of one calf following S1 radiculopathy; the second had a hypertrophy of tibialis anterior muscle, five years after a compressive injury of the common peroneal nerve. The third case is a global hypertrophy of leg muscles after intensive care or legionella neuropathy. Previous cases of the literature are reviewed and the various pathophysiological hypothesis are considered. Among these hypothesis, the role of abnormal electrophysiological activities in most previous cases, as well as in ours (namely complex repetitive discharges and fasciculations), seems the most consistent.

Adult↗
PubMed1995

Narcolepsy associated with arteriovenous malformation of the diencephalon.

Narcolepsy associated with localized brain lesions is rare, and few reports of well-documented cases have been published. We describe the case of a 20-year-old male (HLA DQw1 negative) who fulfilled clinical and polygraphic criteria of symptomatic narcolepsy. Narcolepsy in this patient was associated with an arteriovenous malformation involving the structures around the third ventricle. Clinical symptoms improved after embolization and radiosurgery. These findings support the hypothesis that lesions in the vicinity of the third ventricle can cause symptomatic narcolepsy.

Adult↗
PubMed1995

Effects of subcutaneous formalin on the activity of trigeminal brain stem nociceptive neurones in the rat.

1. The subcutaneous injection of Formalin (5%, 50 microliters) into the receptive field of convergent (wide dynamic range) nociceptive neurons in the spinal dorsal horn has previously been reported to produce a prolonged biphasic response with a time course similar to the observed in behavioral experiments. However, conflicting data in other studies led us to examine the effects of Formalin on the activity of convergent nociceptive neurons at two levels of the trigeminal (V) brain stem complex, namely V subnuclei oralis (Sp5O) and caudalis (Sp5C). 2. Single neuron activity was extracellularly recorded in anesthetized rats. Each neuron was classified as convergent on the basis of its responses to both mechanical and transcutaneous electrical stimuli applied to its mechanoreceptive field (RF). All neurons responded to innocuous and noxious mechanical stimuli and had electrically evoked responses corresponding to both A and C fiber afferent inputs. Seventeen Sp5O and 32 Sp5C convergent neurons received an injection (50 microliters sc) of 5% Formalin into the center of their RF. 3. Three groups of neurons were distinguished: one group that was not activated by the Formalin injection (Sp5O, n = 1; Sp5C, n = 2), another group that responded only with an early and short-lasting response [monophasic neurons: Sp5O, n = 11 (65%); Sp5C, n = 10 (31%)], and a third group that responded with two phases separated by a short period of quiescence [biphasic neurons: Sp5O, n = 5 (29%); Sp5C, n = 20 (62.5%)]. The proportion of biphasic neurons was significantly higher in Sp5C than in Sp5O. 4. The first phases of the Sp5O neurons were not significantly different in terms of duration and frequency from those of the Sp5C neurons. However, duration and discharge frequency of the first phase of biphasic neurons were significantly greater than for monophasic neurons in Sp5C (nonsignificant in Sp5O). The second tonic period of excitation of all biphasic neurons was gradual in outset and offset, and long in duration (23-39 min). The duration of the second phase was significantly longer for the biphasic neurons in Sp5C than for those in Sp5O. 5. Our findings suggest that the mono- and biphasic neurons may have different roles in the transmission of nociceptive information induced by the peripheral injection of Formalin.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1995

[Cervical spinal cord compression caused by ossification of the posterior vertebral ligament. Apropos of a case].

Progressive cervical myelopathy due to an ossification of the posterior longitudinal ligament (OPLL) appeared in a sicilian women. Diagnosis was made by lateral conventional tomograms and CT Scan with mielography. Corporectomy of the 5th vertebra and ablation of the ligament dramatically improved the clinical symptoms. If OPLL seems a common cause of cervical myelopathy in Japan, it is very rate in Caucasian people. Instead of the origin of the patients, progressive tetraparesis of the 60 years old people is the usual presentation of this affection. The cause of OPLL remains unknown: genetic factors, vitamin A, association with diffuse idiopathic skeletal hyperostosis, calcium metabolism abnormalities are discussed. As far as surgical treatment is concerned, choice between anterior and posterior decompression is clarified on the basis of the type and the extension of OPLL.

Adult↗
PubMed1994

Uncompacted myelin lamellae in polyneuropathy, organomegaly, endocrinopathy, M-protein and skin changes syndrome. Ultrastructural study of peripheral nerve biopsy from 22 patients.

Mechanisms of peripheral neuropathies in polyneuropathy, organomegaly, endocrinopathy, M-protein and skin changes (POEMS) syndrome are poorly understood. A peripheral nerve biopsy was performed in 22 patients. Of these 9 had histological features of Castleman's disease on lymph node biopsies, and 19 had a monoclonal lambda light chain in their serum. Certain nerve fragments were paraffin embedded, others were frozen and studied by direct immunofluorescence, and others were fixed for ultrastructural examination. Paraffin-embedded fragments did not show any amyloid deposits, and at direct immunofluorescence there was no immunoglobulin fixation. At ultrastructural examination, features of uncompacted myelin lamellae (UML) were present in 19 patients, and their frequency varied from 1% to 16% of myelinated fibres. Up to now UML have been reported only in 7 patients with POEMS syndrome in the literature. UML have also been noticed in a few cases of inflammatory demyelinating polyradiculoneuritis and inherited tendency to pressure palsy.

Aged↗
PubMed1993

[Rhabdomyolysis in severe acute asthma].

A case is reported of a 74-year-old man who developed rhabdomyolysis during treatment for status asthmaticus. This patient had a history of asthma. He was admitted after a cardiac arrest during a severe asthma attack. Continuous muscle relaxation (4 mg.h-1 of pancuronium for 10 days; total dose 960 mg) was required to carry out mechanical ventilation. Bronchodilators and high doses of steroids (300 mg.day-1 of methylprednisolone for 10 days) were also given. After the administration of muscle relaxant had been discontinued, the patient displayed a severe, predominantly proximal, quadriplegia as well as a raised blood creatinine kinase concentration. The urine was brown coloured over a 24 h period. Rhabdomyolysis was confirmed by muscle biopsy. The patient recovered over a period of one month. This case is discussed in the light of some other similar reports in the literature. It seems that the combination of muscle relaxant with high doses of steroids is to be incriminated.

Acute Disease↗
PubMed1993

[Trigeminal neuropathy and connective tissue diseases].

Connective tissue diseases are a rare and poorly understood etiology of trigeminal neuropathy. In a retrospective multicentric study covering 12 years. 12 cases were identified in the archives of the Departments of Neurology, Rheumatology and Internal Medicine: 4 were associated with progressive systemic sclerosis. 4 with mixed connective tissue diseases and 4 with Sjögren's syndrome. In 9 of the cases, the neuropathy led to the diagnosis of connective tissue disease. Trigeminal neuropathy usually developed during the evolution of the connective-tissue disease but, in 3 cases, it preceded other clinical signs. As a rule, the connective tissue disease was relatively inactive when the trigeminal nerve was involved. The neuropathy was usually unilateral (9 times), localized to the inferior branch(es) of the trigeminal and manifested itself by an isolated sensation of cutaneous numbness associated with paresthesias. Only one patient had mixed motor and sensory involvement. The topography of the lesions (peripheral, truncal, radicular or central nuclear) remains unknown in most cases, however, electromyographic study of the blinking reflex in 2 patients confirmed peripheral neuropathy in both of them. Corticotherapy had only a minor effect: neuralgia was rare and carbamazepine was ineffective. The pathogenicity of trigeminal involvement is discussed and these observations are compared to the 151 cases reported in the literature.

Adult↗