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Biomedical subjects

C Meier

Publications and source records attributed to C Meier.

At least 163 records · Page 9Linked to original sources
PubMed1985

Heterogeneity of congenital motor and sensory neuropathies.

Six children suffering from a congenital motor and sensory neuropathy (CMSN) are described. Severe muscle hypotonia, areflexia and a delay of motor development are detectable in all of them. Sural nerve biopsies exhibited an almost complete absence of myelinated fibres and a correspondingly slow nerve conduction velocity (NCV) of less than 10 m/s was detectable in four patients. A few segments with hypermyelination adjacent to gross hypomyelination were seen in the fifth patient, and the NCV was 15 m/s. The sural nerve of the sixth patient showed a loss of thick myelinated nerve fibres, and his NCV was 25 m/s. These results demonstrate the histological heterogeneity of CMSN which was already detected by the NCV. The relation of our findings to the classification of HMSN by Dyck and Lambert (1968) is discussed.

Child↗
PubMed1985

Passive transfer studies in demyelinating neuropathy with IgM monoclonal antibodies to myelin-associated glycoprotein.

Serum or IgM fraction from two patients with a demyelinating neuropathy and IgM monoclonal antibodies to myelin-associated glycoprotein were injected in three different animal species. There were no clinical, electrophysiological or morphological signs of demyelination in either chronic or acute passive transfer experiments. These results suggest that the pathogenesis of this human demyelinating neuropathy may be more complex than has been assumed.

Animals↗
PubMed1985

Refsum's disease: management by diet and plasmapheresis.

A case of Refsum's disease treated by serial plasma exchanges together with a moderate low phytanate diet is reported. Serial plasma exchanges determined a rapid significant clinical improvement (neuropathy and cerebellar ataxia) that allowed immediate return to full-time employment. The initial improvement could be maintained by intermittent serial plasmapheresis despite partial failure of the initially introduced low phytanate diet bringing 20 mg phytanic acid daily. A new dietary regimen bringing 10 mg phytanic acid was later introduced that was well tolerated. No liquid formula was used. The clinical improvement was clearly correlated to a fall in serum phytanic acid from 45.3 to 16.2 mg/100 ml.

Adult↗
PubMed1985

Coronary artery bypass grafts. Influence of preoperative risk factors on the late postoperative course.

In order to assess the influence of preoperative risk factors on the late postoperative course, 186 consecutive patients in whom coronary artery bypass graft (CABG) was performed for chronic stable angina (169 men, 17 women, mean age +/- SD 54 +/- 8 years) were followed for an average of 54 (6 to 113) months. The overall five-year survival rate by life-table analysis was 90 +/- 2 percent. The postoperative course was considered favorable in 112 patients (60 percent) in whom angina was absent or improved by at least 2 NYHA classes throughout the entire follow-up, and was unsatisfactory in 74 patients. It was concluded that the late postoperative course of patients with CABG was unfavorably influenced by the presence of two or three risk factors, and a high preoperative cholesterol level was the only single risk factor associated with unsatisfactory outcome.

Adult↗
PubMed1984

[Immunopathogenesis of polyneuropathies in paraproteinemia].

Polyneuropathies are the most common neurological complications of paraproteinemias . In many cases pathogenesis remains unclear. In two patients with chronic demyelinating neuropathy in IgM-paraproteinaemia subtle methods were applied ( immunoelectroblot and immunocytochemistry). It could be demonstrated that the pathologic antibodies in the patients' serum reacted specifically with an antigen in the sheath, the myelin-associated glycoprotein. These observations suggest an antibody-mediated immunopathogenesis of the patients' polyneuropathy and invite prospects for a rational treatment with immunosuppressive approaches.

Aged↗
PubMed1984

Nemaline myopathy appearing in adults as cardiomyopathy. A clinicopathologic study.

We examined a 29-year-old woman with nemaline myopathy that appeared as cardiomyopathy. Clinical examination showed dilated cardiomyopathy, but no neuromuscular abnormalities of the skeletal muscles. Electromyography showed neither neurogenic nor myopathic abnormalities. A biopsy specimen from the quadripecs muscle showed typical nemaline bodies in about 50% of the muscle fibers. The patient died six months later of biventricular heart insufficiency. Autopsy revealed nemaline bodies in the working and conducting tissues of the myocardium. Earlier, the patient's mother and one of her sisters died unexplained, sudden deaths at the ages of 47 and 37 years, respectively. Sections of the myocardium taken from the sister at autopsy were available, and also disclosed nemaline bodies after restaining with trichrome.

Adult↗
PubMed1984

Polyneuropathy in Waldenström's macroglobulinaemia: reduction of endoneurial IgM-deposits after treatment with chlorambucil and plasmapheresis.

A case of progressive polyneuropathy associated with Waldenström's macroglobulinaemia is reported. A monoclonal IgM-lambda gradient was detected in the serum and cerebro-spinal fluid. By electro-immunoblot analysis antibodies against myelin-associated glycoprotein were found in the serum and cerebro-spinal fluid. The motor and sensory conduction velocities of several peripheral nerves were markedly decreased, and examination of visual evoked potentials (VEPs) revealed pathological latencies. Sural nerve biopsies before and after treatment with chlorambucil and plasmapheresis showed nerve fibre loss and demyelination. In the pre-treatment biopsy, heavy accumulations of filamentous material were found which stained positively for IgM by immuno-cytochemistry. Such accumulations had disappeared in a biopsy performed after treatment. The morphological findings were correlated with an improvement of clinical and electro-physiological findings.

Chlorambucil↗
PubMed1984

Demyelinating polyneuropathy associated with monoclonal IgM-paraproteinaemia. Histological, ultrastructural and immunocytochemical studies.

Histological, ultrastructural and immunocytochemical findings of sural nerve biopsies from 2 patients with monoclonal IgM-paraproteinaemia are presented. In both cases the pathological IgM antibodies reacted with a myelin antigen which was identified as myelin-associated glycoprotein (MAG) by immunoelectroblot . Histology and electron microscopy showed typical features of a chronic demyelinating neuropathy with accompanying axonal degeneration. Immunohistochemical studies demonstrated IgM in the vicinity of endoneurial vessels and on some of the myelinated fibres. The localisation of IgM on the myelin sheath showed a typical pattern, which was similar to that found in binding studies with the patients sera on control nerves. It resembled the characteristic immunocytochemical staining pattern of MAG. Binding studies with the patients' sera on human and canine CNS material exhibited a clear labelling of white matter and certain, as yet unidentified structures within the cerebral and cerebellar cortex. In mixed glial cell cultures, the sera of both patients bound specifically to oligodendrocytes. Our observations are interpreted as immunohistochemical evidence that the anti-MAG antibodies of the patients' sera had bound to their antigenic target in the peripheral nerves. Because the antibodies clearly react to central myelin, oligodendrocytes and other not yet identified cortical structures, CNS involvement in such disorders should be considered.

Aged↗
PubMed1984

Tetrodotoxin-resistant release of 3H-noradrenaline from the mouse vas deferens by high intensity electrical stimulation.

Vasa deferentia of mice were preincubated with 3H-noradrenaline and then superfused with a medium containing cocaine 10 microM and phentolamine 30 microM. The tetrodotoxin-resistant outflow of tritium evoked by high intensity electrical field stimulation (0.5 Hz, 200 mA current strength, 2 ms pulse width) was studied and, in some experiments, compared with the tetrodotoxin-sensitive outflow evoked by low intensity electrical field stimulation (0.5 Hz, 50 mA, 1 ms). In contrast to the outflow evoked by low intensity stimulation, the outflow evoked by high intensity stimulation was increased in Na+-free medium, and was only partly dependent on the external Ca2+ concentration. The Ca2+-dependent fraction consisted mainly of 3H-noradrenaline. Again, in contrast to the outflow caused by stimulation at low intensity, that caused by stimulation at high intensity was not reduced by Mg2+ 20 mM, Co2+ 5 mM or normorphine 40 or 100 microM, and was not enhanced by tetraethylammonium 5 mM or 4-aminopyridine 1 mM. It is concluded that high intensity electrical stimulation elicits a tetrodotoxin-resistant, calcium-dependent release of noradrenaline which differs in mechanism from the release elicited by action potentials.

4-Aminopyridine↗
PubMed1984

Neurologic disorder of vitamin E deficiency in acquired intestinal malabsorption.

Fifteen years after onset of a malabsorption syndrome, a 49-year-old man had sensory and oculomotor disorder with marked vitamin E deficiency. After 6 months of treatment with high parenteral doses of vitamin E, the neurologic signs slowly receded, but the patient died of gastrointestinal hemorrhage. Autopsy and sural nerve biopsy showed the changes in both central and peripheral nerves; these changes are considered characteristic of vitamin E deficiency.

Adult↗
PubMed1984

[Polyneuropathies and gammapathies: a form with antiglycoprotein MAG antibodies].

Two cases of polyneuropathy with IgM gammopathy are reported. Myelin associated glycoprotein is the antigen for the monoclonal antibody in both of these patients. The same antigenic specificity has now been identified in other patients having a paraproteinemia with a polyneuropathy. These findings suggest the existence of a new syndrome characterized by: a) a primary demyelinating neuropathy; b) a monoclonal IgM antibody to a specific glycoprotein component of myelin, referred to as myelin associated glycoprotein (MAG). As in other humorally mediated autoimmune diseases, it is suggested that demyelination is caused by circulating anti-MAG antibodies. The role of immunosuppressive drugs and plasmapheresis is discussed.

Aged↗
PubMed1983

The central-peripheral transition zone of cervical spinal nerve roots in Jimpy mutant and normal mice. Light- and electron-microscopic study.

Comparative morphological and ultrastructural investigations on the cervical dorsal and ventral central-peripheral transition zones (CPTZs) of Jimpys and control mice have been performed at early and advanced myelination stages. After postnatal development a characteristic cone-shaped glial outgrowth extends into the proximal part of the dorsal roots, while the ventral roots exhibit short Schwann cell and peripheral nervous tissue invaginations into the spinal cord at the ventral root-spinal cord junction in both animal groups. In Jimpys, although there is marked central myelin deficiency and absence of oligodendroglial development on the CNS side, the normal general aspect of the CPTZs is maintained. Previously postulated astrocytic and neuroaxonal abnormalities in the mutants do not alter the central-peripheral borderline, and Schwann cell migration from the spinal nerve roots into the cord does not occur.

Animals↗