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Biomedical subjects

S Metral

Publications and source records attributed to S Metral.

At least 19 recordsLinked to original sources
PubMed2000

The course and prognostic factors of familial amyloid polyneuropathy after liver transplantation.

Familial amyloid polyneuropathy (FAP) associated with mutations of the transthyretin (TTR) gene is the most common type of FAP, a devastating disease causing death within 10 years after the first symptoms. Because most of the amyloidogenic mutated TTR is secreted by the liver, transplantation is widely used to treat these patients, but long-term quantitative evaluation of the effects of liver transplantation on the progression of the neuropathy are not available. We have treated 45 patients with symptomatic TTR-FAP, including 43 with the Met30 TTR gene mutation, and report on the results of periodic evaluation of markers of neuropathy in 25 of them, who have been followed for more than 2 years after liver transplantation (mean follow-up 4 years). The overall survival rates at 1 and 5 years were 82 and 60%, respectively. Urinary incontinence and a low Norris score at liver transplantation were associated with poorer outcome. The motor score stabilized in seven of 11 patients (64%) with mild sensorimotor neuropathy (walking unaided) and in two of the eight patients (25%) with severe sensorimotor deficit (walking with aid) at liver transplantation. In five other patients, deterioration of motor deficit occurred only within the first year after liver transplantation, but was progressive after this interval in two patients. None of the six patients with pure sensory neuropathy developed motor loss and superficial sensory loss remained unchanged. Two years after liver transplantation, the rate of myelinated axon loss in nerve biopsy specimens was markedly lower in seven transplanted patients (0.9/mm(2) of endoneurial area/month) than in non-transplanted patients (70/mm(2) of endoneurial area/month). Symptoms of dysautonomia and quantitated cardiocirculatory autonomic tests remained unchanged. In all patients, serum mutated TTR decreased to 2.5% of pre-liver transplantation values and remained at this level during follow-up. We presently recommend liver transplantation in FAP patients at onset of first symptoms and exclusion of those with a Norris score below 55 and/or with urinary incontinence.

Action Potentials↗
PubMed1998

Acute inflammatory demyelinating polyradiculopathy in children: clinical and electrodiagnostic studies.

Clinical and electrophysiological features in 43 children with acute inflammatory demyelinating polyradiculoneuropathy (AIDP) were retrospectively studied. More than one-third of these children were less than 3 years old. Some distinctive clinical features specific to adults or to children were identified. Initial symptoms such as ataxia and severe limb or back pain were more frequent in children. By using the criteria suggested here, according to our neurophysiological findings, the diagnosis of AIDP could be proposed as early of the first days of illness in 90% of the children and is confirmed during the second week. The neurophysiological evolution was very similar in children and adults except that recovery occurred sooner in children. Prognosis was better in childhood (complete recovery in all but 2 patients with minor disabilities).

Acute Disease↗
PubMed1998

Bone marrow transplantation in metachromatic leukodystrophy caused by saposin-B deficiency: a case report with a 3-year follow-up period.

A 2-year-old child had a metachromatic leukodystrophy-variant phenotype mainly involving the peripheral nervous system (PNS) that was caused by saposin-B deficiency. Bone marrow transplantation resulted in transient deterioration then continuous improvement of PNS functions. These findings were supported by nerve conduction velocity measurements, but the symptoms ultimately worsened. Magnetic resonance imaging showed persistent white matter lesions and progressive pontocerebellar atrophy.

Bone Marrow Transplantation↗
PubMed1998

[Correlations between clinical deficits, motor and sensory evoked potentials and radiologic aspects of MRI in malformative syringomyelia. 27 Cases].

Twenty-seven patients (15 males, 12 females, age range: 16-66 years) were admitted for malformative syringomyelia diagnosed on MRI with measures of syrinx extending and transverse diameter. Posterior tibial somatosensory evoked potentials (PT SEP), median (M SEP), trigeminal (V3 SEP), brain stem auditory evoked potentials (BEAP), cortical and cervical motor evoked potentials (MEP) were correlated with clinical and radiological findings. SEP abnormalities were not correlated with the duration of symptoms. PT SEP proved to be more sensitive than M SEP. MEP abnormalities were very frequent (87% of the cases), even without clinical motor deficits. Trigeminal SEP were more sensitive than BEAP which were not related to the presence of associated cranio-vertebral abnormalities. We found no significative relationship between clinical and radiological results. Moreover, there was a positive relationship between electrophysiological and radiological results: abnormal trigeminal SEP were detected in 85% of the patients with high cervical syringomyelia. In all cases, trigeminal SEP and MEP should be done in association with M and PT SEP as both of them detect subclinical evidence of spinal cord dysfunction in syringomyelia.

Adolescent↗
PubMed1993

Anterior spinal artery syndrome mimicking infantile spinal muscular atrophy.

A baby with acute fetal distress and severe heart malformation presented with persisting hypotonia and muscle weakness. Clinical, electromyography, and muscle biopsy findings were compatible with anterior horn cell disease. Postmortem study showed widespread ischemic necrosis in the anterior gray matter of the spinal cord. This is the first report of anterior spinal artery syndrome in a neonate.

Diagnosis, Differential↗
PubMed1990

Conduction block in neuropathies with necrotizing vasculitis.

Thirty-two patients with a mononeuropathy multiplex associated with a systemic necrotizing vasculitis were studied. The main abnormality was a loss of motor and sensory axons confirmed by electrophysiological and histological methods. A conduction block was observed in five patients, but only one was at a usual site of compression. Based on previous pathological studies and the experimental data in human and animals, the mechanism of the block is proposed to be ischemic. It is suggested that a conduction block in one nerve in a neuropathy with two or more individual nerves affected and with electrophysiological features of axonal degeneration may be due to a vasculitis.

Adult↗
PubMed1989

[Serum demyelinating activity and Guillain-Barre syndrome: favorable effect of plasma exchange].

The present study was designed to determine whether plasma exchange has a beneficial effect on the activity of the demyelinating factor present in the serum of patients with the Guillain-Barre syndrome. The demyelinating activity was assessed electrophysiologically after subperineurial injection of 20 to 30 microliters of serum into the rat sciatic nerves Serum was obtained from 26 patients from the French Cooperative Trial, among whom 12 had plasma exchange. Sera were drawn at hospital admission (DO) and at D15, D30 and D60. They consistently produced conduction block in a large proportion of motor axons, measured by the ratio of amplitudes of the motor action potential elicited by stimulation at both proximal and distal sites of injection. The serum activity diminished during the time course of the illness earlier in patients receiving plasma exchange and even more in patients with the less severe clinical score at the plateau phase. Serum from patients without motor sequelae after one year evolution did not produce conduction block prior to D30, as compared to sera from patients with sequelae which were still very active. This work add biological data to the positive results of plasma exchange in Guillain-Barre syndrome obtained by the North American and French Cooperative Trials.

Adult↗
PubMed1982

[Electrophysiological and morphological effects of the injection of Guillain-Barré sera in the sciatic nerve of the rat (author's transl)].

Serum from 3 of 4 patients with classical Guillain-Barré syndrome has produced conduction block in a large proportion of motor axons following subperineurial injection into 13 rat sciatic nerves. These effects, although qualitatively similar to those previously described for certain experimental sera (EAN, EAE, and anti-Gal-Cer), are notably slower in evolution. Conduction block does not begin until more than 24 hours after injection and is maximal at about 5 days. Between 6 and 8 days the appearance of long latency responses signals return of conduction in previously blocked axons. Thereafter return to control values is rapid and complete within 10 to 15 days. Six control human sera injected into 13 sciatic nerves have shown no comparable effect. Correlative morphological studies indicate that these Guillain-Barré sera produce focal demyelination which evolves pari passu with conduction block. Demyelination appears to evolve both by vesicular disruption and by macrophage mediated myelin stripping. A factor is present in the serum of some patients with Guillain-Barré syndrome, which given access to the endoneurial environment produces active demyelination with conduction block. We believe that the production of this factor could be responsible for the polyradiculoneuropathy of this disease.

Animals↗
PubMed1981

Relationship between force and integrated EMG activity during voluntary isometric anisotonic contraction.

The surface electromyogram (EMG) was recorded for the extensor carpi radiales of normal human subjects during voluntary isometric anisotonic contractions as well as the force generated by the muscle. The relationship between force and instantaneous integrated EMG could not be fitted by a single linear function or a parabola. The muscle was then considered as a system (A) presenting a maximum force and (B) in which the EMG activity represented the input and the contraction force the output, that is F = f(iEMG) and not, as is usually done, iEMG = f(F). In addition the summed iEMG from the beginning of the contraction was used since the actual force depends on all preceding events. These findings let to testing for a non-linear and asymptotic function relating F to iEMG. A double exponential function: (formula: see text) could account for the two mechanisms by which the force of a voluntary contraction is increased.

Calcium↗
PubMed1981

[Medio-cubital anastomosis in the forearm (author's transl)].

Communication between median and ulnar nerves in the forearm may occur in at least 15% of the population. Electromyography with nerve stimulation is the method necessary for the diagnosis. Four cases with the anatomical feature are reported. The authors insist on electromyographic criteria to distinguish this anomaly from communication between the two nerves in the hand or partial or complete overlap or replacement of the motor field of one nerve by the other. The clinical and pathophysiological consequences of the MARTIN-GRUBER anastomosis are discussed.

Adult↗
PubMed1976

[Modification by vincristine action of the appearance of miniature potentials in the frog neuromuscular junction].

Effects of Vincristine (VCR) are compared to those of Vinblastine (VLB) on spontaneous miniature end-plate potentials (mepp) recorded intracellulary from myoneural junctions of the frog. A decrease of mepp amplitude and an enhancement of mepp frequency are observed with VCR as well as VLB. But VCR induces spontaneous giant potentials later than VLB, only after washing the preparation with drug-free Ringer solution for 20-40 min. It is concluded that VCR may interact with several pre- and post-synaptic loci.

Animals↗