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Biomedical subjects

A Steck

Publications and source records attributed to A Steck.

At least 37 records · Page 2Linked to original sources
PubMed1994

Pulmonary hyperplasia in the Fraser cryptophthalmos syndrome.

We report on 2 sibs with the Fraser cryptophthalmos syndrome who had pulmonary hyperplasia and laryngeal stenosis. A third unrelated patient with Fraser syndrome had laryngeal stenosis, renal agenesis, and normal lung development, rather than the expected pulmonary hypoplasia. Three additional cases of pulmonary hyperplasia in the Fraser syndrome were ascertained from a review. In all of these cases the likely mechanism for pulmonary hyperplasia is retention of fetal lung fluid by laryngeal or tracheal obstruction.

Abnormalities, Multiple↗
PubMed1993

[Fatal peripheral neuropathy with predominant motor involvement associated with anti-MAG IgM monoclonal gammapathy].

A 75 year old woman died of predominantly motor peripheral neuropathy with amyotrophy and fasciculations progressing to tetraplegia and death within 19 months. There was a mild distal sensory loss. At electrophysiology, the pattern was initially demyelinating and later became axonal. Nerve biopsy disclosed severe myelinated and unmyelinated fiber loss with wallerian degeneration. The remaining fibers had demyelination widening of the external myelin lamellae and intense hypermyelination. Serum contained an anti-MAG monoclonal IgM reacting with SGPG. Two siblings without monoclonal gammopathy had died of definite amyotrophic lateral sclerosis. This family association is discussed.

Aged↗
PubMed1992

Childhood peripheral neuropathy with autoantibodies to myelin glycoprotein P0.

The serum of a 4-year-old child with severe hypertrophic peripheral neuropathy contained high-titer polyclonal antibodies, mainly of IgG class, reacting with the 30-kd P0 glycoprotein of peripheral nerve. This was demonstrated by indirect immunofluorescence, immunoblot analysis of myelin proteins, and enzyme-linked immunosorbent assay with purified P0 glycoprotein. The antibodies did not react with myelin-associated glycoprotein, sulfated glycuronic acid-containing paragloboside (SGPG and SGLPG), or other peripheral nerve glycolipids or gangliosides. To our knowledge this is the first report of strong antibody activity specifically directed against P0. This antibody may play a causative role in the pathogenesis of the peripheral neuropathy in this patient.

Autoantibodies↗
PubMed1990

Immunological heterogeneity of autoreactive T lymphocytes against the nicotinic acetylcholine receptor in myasthenic patients.

The response of human T lymphocytes against the nicotinic acetylcholine receptor (AChR) was studied in five patients with myasthenia gravis (MG) and in six healthy donors using either native Torpedo AChR or recombinant protein derived from the mammalian AChR alpha subunit (X4, residues 6-216 of mouse AChR alpha subunit). The present study demonstrates that (a) AChR-specific T helper cell lines can be generated from MG patients [either from peripheral blood lymphocytes (PBL) or from thymocytes] as well as from PBL of normal controls, (b) lymphocytes from MG patients, but not from controls, recognize the mammalian AChR but not the Torpedo receptor, (c) in humans, the HLA-DR2-associated T cell epitope is probably located in the region of residues 162-216 of the AChR alpha subunit and (d) there is a considerable heterogeneity of autoreactive T cell responses: (i) T cell lines from different HLA-type donors have distinct epitope profiles; (ii) the epitope specificity of the PBL-derived T cell line is different from that of the thymocyte-derived line; (iii) the epitope specificities of patient-derived T cell lines are different from those generated from normal controls who share the same HLA phenotype.

Animals↗
PubMed1987

Chronic progressive neurological involvement in Borrelia burgdorferi infection.

Five patients with chronic meningitis were hospitalized several times for progressive neurological symptoms. The clinical manifestations included cranial neuritis, radiculoneuritis, myelitis and encephalitis. In two cases cerebral infarction occurred. The course was commonly characterized by a tendency to deteriorate. From the clinical point of view, it was repeatedly difficult to exclude multiple sclerosis or tuberculous meningitis. Finally, specific antibodies against Borrelia burgdorferi were detected by indirect immunofluorescence assay. The diagnosis of a borreliosis was not considered initially because there was no history of tick-bite or erythema chronicum migrans, and the neurological involvement of the central nervous system seemed unusual. The latency between the first symptoms and diagnosis varied from 3 months to 5 years. After a parenteral, high-dose therapy with penicillin, there was a significant improvement in all patients. In two cases, there was evidence of intrathecally produced antibodies to myelin basic protein.

Adult↗
PubMed1986

Studies on the intrathecal humoral immune response in canine distemper encephalitis.

Albumin and IgG were quantitated in paired cerebrospinal fluid (CSF) and serum samples from dogs with demyelinating canine distemper virus (CDV) infection by means of rocket immunoelectrophoresis. The IgG index as indicator for intrathecal immunoglobulin synthesis was normal in animals with non-inflammatory demyelinating lesions and elevated in dogs with inflammatory myelin lesions. Specific antibodies against CDV and myelin were quantitated in CSF and serum from 8 dogs with an elevated IgG index. Eight of these dogs had significant amounts of antimyelin antibody and 4 dogs had neutralizing anti-CDV antibody in the CSF. Whereas the pathogenetic significance of antimyelin antibodies remains uncertain, the intrathecal antiviral immune response provides a plausible explanation for immunopathologic destruction of myelin in distemper.

Albumins↗
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

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

Myelin-associated glycoprotein is produced before myelin basic protein in cultured oligodendrocytes.

Mixed glial cell cultures from neonatal dog cerebellum were harvested daily between 3 and 21 days after seeding and studied with immunocytochemical techniques for the demonstration of myelin-associated glycoprotein (MAG) and myelin basic protein (MBP). Both MAG and MBP were detected in the cultures and by means of double labelling techniques shown to be produced by the same cells. MAG+ cells occurred earlier and were always more numerous than MBP+ cells. These results suggest that the oligodendrocyte in vitro expresses MAG before MBP. The findings are discussed in respect to oligodendroglial differentiation and myelination in vivo.

Animals↗
PubMed1984

Morphological and immunocytochemical characterisation of mixed glial cell cultures derived from neonatal canine brain.

Three different regions from neonatal dog brain were mechanically dissociated and cultured. At seven, 10, 14 and 19 days, cultures were harvested and studied with immunocytochemical techniques for the demonstration of astrocytes, oligodendrocytes and fibroblasts. The canine brain cultures were confluent at seven days and contained fibroblasts, both types of glial cells and several small fragments of undissociated brain tissue. Many cells were myelin associated glycoprotein (MAG) positive. In the older cultures increasing numbers of myelin basic protein (MBP) positive oligodendrocytes were also demonstrated. Double labelling studies demonstrated that MBP and MAG were produced by the same cells. MAG positive cells were therefore identified as oligodendrocytes. Most intensive oligodendroglial growth occurred in the vicinity of undissociated tissue fragments. The results were discussed in respect to glial differentiation and the question of whether the canine cultures may contain neurons.

Animals↗