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M Vandevelde

Publications and source records attributed to M Vandevelde.

At least 109 records · Page 6Linked to original sources
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.

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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.

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PubMed1984

Interleukin 1- and 2-like activities in the dog.

Canine adherent and non-adherent peripheral blood leukocytes and spleen cells were examined for their ability to produce soluble factors with Interleukin 1- and 2- (IL-1 and IL-2) like activities. For this purpose, three conventional assay systems were used: (a) proliferation on an IL-2-dependent murine cytotoxic T-lymphocyte cell line, (b) enhancement of PHA-induced murine thymocyte proliferation and (c) proliferation of lectin-primed canine peripheral blood lymphocytes (PBL). Only the latter two types of cells respond to IL-1, whereas all three types respond to IL-2. Both types of factors were produced and the kinetics of their release/production were found to be identical to those of human PBL. Results suggested that species-related differences existed. Canine interleukin-containing supernatants had higher titers than murine interleukin-containing supernatants when analyzed on canine lymphocytes, and the reverse was found if murine target cells were used.

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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

[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.

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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↗
PubMed1984

Immunoelectrophoretic determination of albumin and IgG in serum and cerebrospinal fluid in dogs with neurological diseases.

Albumin and IgG concentrations were determined in the cerebrospinal fluid (CSF) and serum from 21 normal dogs and 79 dogs with neurological disease, using rocket immunoelectrophoresis. A qualitative protein reaction, cell count and cytological examination were also performed on most CSF samples. The values obtained in normal dogs were used to establish baseline data. Those obtained in neurologically ill dogs were divided into five groups according to the clinical and pathological findings; infectious inflammatory diseases, tumours, degenerative conditions, spinal cord compression and vascular disorders. The absolute CSF albumin content was used as an indicator for blood-brain barrier disturbance and the IgG index for the detection of intrathecal IgG synthesis. Four categories of findings were distinguished; normal CSF, blood-brain barrier disturbance (increased transudation), intrathecal IgG synthesis, combined barrier disturbance and IgG synthesis. The results correlated largely with the pathological findings although in some cases the CSF values could not be explained by the morphological data. It was concluded that rocket immunoelectrophoresis, although it is an elaborate technique, is a useful addition to other CSF examination methods.

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PubMed1983

Degenerative myelopathy in a family of Siberian Husky dogs.

Three closely related, Siberian Husky dogs had chronic progressive paresis and ataxia with muscle atrophy in the hindlimbs. Radiologic and myelographic examination of the spine revealed no abnormalities. On histologic examination, disseminated degeneration of the white matter, particularly in the thoracic segments, was seen. The clinical and pathological findings were similar to those described in aging large dogs with so-called degenerative myelopathy. The cause of this disease is unknown but the fact that these 3 Huskies were closely related suggest that hereditary factors may play a role.

Animals↗
PubMed1983

Canine distemper virus-induced glial cell changes in vitro.

In vitro studies on glial cell changes in canine distemper virus (CDV) infection could be useful for the understanding of the pathogenesis of demyelination in vivo in this disease. Mixed glial cell cultures derived from neonatal mice and dogs were infected with CDV and examined using immunocytochemical techniques demonstrating specific oligodendroglial and astroglial cell markers. Astrocytic changes were similar in both murine and canine cultures and consisted of loss of processes, cell fusion, and cell necrosis. Marked oligodendroglial lesions were apparent in the canine brain cultures and were characterized by focal perikaryal protrusions, swelling and loss of cell processes, and cell necrosis. Fusion between oligodendrocytes was not observed. Fusion between astrocytes and oligodendrocytes could not be documented with double labeling techniques. In contrast to the canine cultures, murine oligodendrocytes remained relatively unaffected by the infection. These findings were discussed with respect to cell pathology and mechanisms of demyelination in vivo. The exact nature of the canine oligodendroglial lesions in vitro needs to be studied in further experiments.

Animals↗
PubMed1983

Glial proteins in canine distemper virus-induced demyelination. A sequential immunocytochemical study.

A temporal series of demyelinating lesions in experimental canine distemper virus (CDV) infection was examined with immunohistological techniques demonstrating myelin basic protein (MBP), myelin-associated glycoprotein (MAG), and glial fibrillary acidic protein (GFAP) on serial sections. The earliest lesions were characterized by decreased MBP and MAG and increased GFAP. During the further progression of the disease, MBP and MAG losses continued to match each other. There was no indication of MAG loss preceding the disappearance of MBP. In the more advanced lesions there was a marked decrease of GFAP positive cells. Since these findings differed considerably from similar immunohistochemical studies in progressive multifocal leukoencephalopathy (PML) where demyelination results from oligodendroglial infection, it was concluded that the oligodendroglial cell body is not the primary target of CDV. The marked astroglial changes were also considered to contribute to demyelination in CDV infection but the mechanism by which this happens remains unknown.

Animals↗
PubMed1983

Sensory neuronopathy in dogs: a study of four cases.

A neurological disease which selectively affects the primary sensory pathways was observed in 4 dogs. Clinical signs were dominated by ataxia due to impaired position sense. Deficient or abnormal pain sensation was also observed. Difficulty in eating probably arose from oral and lingual sensory deficit. The lesions were characterized by degeneration and loss of central and peripheral primary sensory axons, with a predilection for large myelinated fibres. The concept of a sensory neuronopathy was supported by the finding of neuronal degeneration and loss in dorsal root ganglia seen in 2 dogs. The cause of the disease is not known. The presence of mononuclear inflammatory cells in acute lesions suggests an infectious or autoimmune disease. Toxic and genetic factors are also to be considered.

Animals↗
PubMed1983

Human monoclonal antibodies to myelin-associated glycoprotein. Comparison of specificity and use for immunocytochemical localisation of the antigen.

Recent reports demonstrate that a population of patients with gammopathy and demyelinating neuropathy have monoclonal antibodies to myelin-associated glycoprotein. Using the immunoblotting technique we compared the species specificity: human monoclonal antibodies to myelin-associated glycoprotein reacted with human, monkey, calf, dog, rabbit and guinea pig myelin, but not with rat or mouse. On the immunoblot myelin-associated glycoprotein consistently stained as a diffuse band with an apparent molecular weight ranging from 90-100 X 10(3) dalton. Experiments showed that when human CNS myelin had been incubated at 37 degrees C before gel electrophoresis, there was a general shift of staining towards the lower end of the molecular weight range. This low molecular weight myelin-associated glycoprotein, when released from the membrane, contains the antigenic determinant. Peptide mapping by limited proteolysis reveals that the antigenic determinants for 4 different monoclonal antibodies appear to lie very close together in the molecule. The distribution of the antigen was studied in nervous tissue with the unlabelled peroxidase-antiperoxidase method. The results obtained are in close agreement with the localization reported with polyclonal antisera to myelin-associated glycoprotein.

Animals↗
PubMed1983

Lymphocyte responsiveness to lectin and myelin antigens in canine distemper infection in relation to the development of demyelinating lesions.

Eleven dogs were experimentally infected with canine distemper virus and studied for periods of up to 63 days post-inoculation. The responsiveness of lymphocytes in vitro toward phytohemagglutinin, myelin basic protein and galactocerebroside was tested at regular intervals during the course of infection by means of [3H]thymidine incorporation and flow cytometry. All dogs developed a marked decrease of lymphocyte responsiveness toward phytohemagglutinin. Four dogs recovered rapidly from the immunosuppression and did not develop demyelination or had only mild lesions, while two others failed to recover at all and developed severe non-inflammatory demyelinating lesions. The remaining dogs exhibited a slow or partial immune recovery and had various degrees of inflammatory demyelination. Lymphocytes from 2 dogs with demyelination and 2 dogs without myelin lesions responded to myelin antigens. The findings indicate that the degree of immunosuppression in canine distemper virus infection may determine the type of demyelination and autoimmune reactions that occur during the inflammatory stage of demyelination may be epiphenomena.

Animals↗
PubMed1983

Histological immunoenzyme techniques in canine tissues: evaluation of various methods and modifications.

Several antigens including immunoglobulin light and heavy chains, C3, macrophage enzymes and various brain proteins were demonstrated immunohistologically in paraffin sections of canine tissues. The indirect immunoperoxidase, the unlabelled antibody enzyme (PAP), double bridging PAP, and biotinavidin-peroxidase (BAP) methods were compared. The influence of various histological procedures such as fixation and embedding, and other modifications such as enzyme treatment of sections was investigated. The best results were obtained with the PAP and BAP methods on formalin fixed tissues. Trypsin proved to be highly effective for demonstrating certain antigens but required firm adhesion of the sections. Prolonged incubation with the primary antisera improved the results considerably. Based on the results of this study a general strategy for solving immunohistological problems has been proposed.

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