Antiglycolipid antibodies in motor neuropathies.

In peripheral neuropathies with monoclonal gammopathy, mainly IgM, it appears clear from clinical, electrophysiological, and experimental data, that the target glycolipid or glycolipid epitope for the IgM is related to the type of neuropathy--purely sensory, predominantly sensory, or uniquely motor. Investigations have focused on chronic peripheral neuropathies associated with polyclonal IgM reactivity to glycolipids. Although IgM anti-GM1 antibodies are present in normal controls, there is a subgroup of motor neuropathies with high titer anti-GM1 antibodies, mainly multifocal neuropathies with conduction blocks (MMNCB). Another subgroup of MMNCB may include IgM anti-SGPG antibodies that do not cross-react with MAG. The importance of the fine structure of the epitope has to be considered in view of the pathogenicity of the antibody. It may bear consequences on its binding properties on the neuronal surfaces and on its biological implications.

Glial fibrillary acidic protein and beta A4 protein deposits in temporal lobe of aging brain and senile dementia of the Alzheimer type: relation with the cognitive state and with quantitative studies of senile plaques and neurofibrillary tangles.

The aim of this study was to compare brain glial fibrillary acidic protein (GFAP) levels to the modifications of cognitive functions (Blessed test score [BTS]), the density of the main neuropathological lesions (senile plaques [SP] and neurofibrillary tangles [NFT]), and the density of the two main subtypes of beta A4 deposits (classic plaques and diffuse deposits) in a series of patients with normal aging and senile dementia of the Alzheimer type of various degrees of severity. GFAP levels (enzyme-linked immunosorbent assay [ELISA] technique) and the densities of changes were measured in the temporal lobe of 12 women over 75 years of age. Under these conditions, the ELISA assay could determine GFAP in brain homogenates (aqueous-Triton buffer soluble extract) in a range from 2.5 ng to 600 ng per assay. Least affected patients (with a BTS of 19 and over) all ranged below 60 micrograms/mg protein. Most affected patients (with a BTS under 6) ranged above 150 micrograms/mg protein. However, interindividual variations were wide. A significant correlation between the BTS and the amount of GFAP could be found only when using the non parametric test of Spearman. There was a significant positive correlation between the amount of GFAP and the density of 1) SP, 2) NFT both revealed by Bodian's silver stain, and 3) classic beta A4 plaques shown by immunocytochemistry. On the contrary, no correlation was observed with diffuse beta A4 deposits. One case with very large amounts of diffuse beta A4 deposits without SP or NFT showed no associated GFAP reactivity. This suggests that GFAP production is a critical event in the formation of classic SP.

[Study of antiglycolipid antibodies in IgM monoclonal dysglobulinemias associated with peripheral neuropathy]. / Etude des anticorps antiglycolipides au cours des dysglobulinémies monoclonales à IgM associées à une neuropathie périphérique.

An immunological mechanism may be responsible for the peripheral neuropathies related to IgM monoclonal gammopathies. Myelin-associated glycoprotein (MAG) has been found to be one the main target antigens for these paraproteinemias. Glycosphingolipids of peripheral nerve have been also found to be targets for these antibodies, especially a sulfated glycosphingolipid containing glucuronic acid (GLSG) specific for peripheral nerve. Crossed reactivity has been found between MAG and GLSG. Anti-glycolipid antibodies were determined in 14 patients with IgM gammopathy and polyneuropathy. Glycosphingolipids from human peripheral nerve were purified and chromatographed by thin-layer chromatography for immunodetection of the antibodies. The 12 patients who had GLSG antibody activity had a clinical status identical to the reported cases of dysglobulinemic neuropathies with anti-MAG antibodies.

Brain gangliosides of quaking and shiverer mutants: qualitative and quantitative changes of monosialogangliosides in the quaking brain.

Ganglioside compositions in the brains of the mutant mice quaking and shiverer were compared with those of their littermate controls, C57BL/6 and C3HSWV. Neither ganglioside content nor composition of shiverer brains differed from those of the control brains. Change in the ganglioside composition of the mutant brain from that of the control was observed only in the quaking mutant brain, in which monosialoganglioside GM1 was significantly reduced and GM4 was completely absent. The structures of the gangliosides were determined by negative ion fast atom bombardment mass spectrometry, and the GM3 and GM4 gangliosides in the quaking brain were found to be altered in regard to their long-chain base and fatty acid compositions when compared to the normal C57BL/6 brain.

Direct sensitive immunocharacterization of gangliosides on plastic thin-layer plates using peroxidase staining.

A technique for the immunocharacterization of gangliosides on thin-layer plates using a peroxidase-labelled anti-Ig antibody is described. The technique uses plastic plates and does not necessitate any transfer of the antigen onto nitrocellulose for immunodetection. Being extremely sensitive, it permits the characterization of gangliosides which cannot be detected by classical densitometric techniques and allows the detection of gangliosides even in trace amounts in ganglioside mixtures. It appears to be useful for the screening of monoclonal antibodies because of its rapidity. Its specificity was found to be analogous to other immunological techniques such as complement fixation and agglutination.

Cryoprecipitation of an anti-Pr2 monoclonal IgM cold agglutinin in the presence of GM3 ganglioside.

The mechanism of cryoprecipitation of a monoclonal IgM kappa cryoglobulin (Mou) with a cold agglutinin activity of Pr2 specificity has been studied. By immunodiffusion this cryoglobulin reacted (by its Fab' fragment) with micellar GM3, a ganglioside bearing the Pr2 antigenic determinant. In contrast to previous reports that indicated a possible temperature dependent self-association of IgM molecules via an immunological interaction leading to cold precipitation, we could not detect any affinity of this cryoglobulin for IgM when we used passive hemagglutination or an indirect enzyme-linked immunosorbent assay (ELISA). However, a GM3-like ganglioside could be extracted, by drastic methods, from the cryoglobulin studied at 22 degrees C, whereas no GM3 was extracted from two control cryoglobulins. Some minor gangliosides (representing less than 25% of total amount of bound gangliosides) were also extracted from Mou cryoglobulin and these gangliosides were shown to crossreact with GM3, as they specifically bind to Mou cryoglobulin by ELISA. After cryoprecipitation the serum still contained a monoclonal anti-Pr2 IgM kappa. A GM3-like ganglioside could be extracted from this purified IgM, and cryoprecipitability could be induced by the addition of a minute amount of micellar GM3. These results suggest that Mou cryoglobulin circulates as an immune complex and that cryoprecipitation may depend on unique IgM-GM3 (or IgM-GM3 cross-reacting gangliosides) complexes.

Modifications of ganglioside composition in peripheral nerve of myelin deficient Trembler mutant mouse.

Ganglioside distribution was studied in peripheral nerves of normal controls and those of Trembler mutant mouse with defect in Schwann cell differentiation and myelination. Neuraminic acid content was considerably decreased in the mutant. Ganglioside distribution as evaluated by densitometry of resorcinol positive spots on thin-layer chromatography revealed a major peak for GD1a in normal controls. In the mutant, the relative proportion was modified with qualitative modifications in the GD1a area and a tremendous increase in GM3 content. The relation with the intense Schwann cell proliferation observed in the mutant is discussed.

Ganglioside content and pattern in tumor tissue of human neuroblastomas.

The ganglioside content and composition in human neuroblastomas was examined. The densitometric pattern corresponding to the thin-layer chromatography of gangliosides showed no major differences compared to normal brain in the GT area, and variable modifications for GM1 and GD3. The most striking and common features resided in the area corresponding to the disialogangliosides for which is was clear that existed a far more complex pattern than normal human brain.

[Interest of ganglioside analysis in the neuroblastoma (author's transl)]. / Intérêt de l'analyse des gangliosides dans le neuroblastome.

As suggested by Hakomori, one of the mechanisms to explain the abnormal proliferation of tumor cells by loss of contact inhibition could be a modification of membrane gangliosides. We report here a case of neuroblastoma with opsomyoclonia in which the ganglioside profile is abnormal, with a high level of GP3 and GM2, and of other gangliosides which are not present in normal child and adult brains.

Perhexiline maleate-induced lipidosis in cultured human fibroblasts: cell kinetics, ultrastructural and biochemical studies.

Perhexiline maleate reduced the growth of human skin fibroblasts in cell culture at a concentration range of 0.3-3 micrograms/ml. At the highest concentration, the cells survived only four days. Pleomorphic inclusions characteristic of drug-induced phospholipidoses appeared in cultured cells. Analysis of the major lipid classes was performed on cells exposed to 3 micrograms/ml at four days. Gangliosides, phospholipids and cholesterol levels four to six times above controls were found. No major qualitative abnormalities were detected in phospholipids. On the contrary, an abnormal pattern of gangliosides was seen by densitometry of silica gel thin-layer plates with increases of GD3 and of an unknown ganglioside. Drug induced lipidosis may involve other lipids than phospholipids, particularly gangliosides.

[Study of gangliosides in normal (C57B1/6J) and quaking mice. Presence and characterization of a labile ganglioside in alkaline solution]. / Etude des gangliosides chez les Souris normales (C57B1/6J) et Quaking. Présence et caractérisation d'un ganglioside labile en milieu alcalin.

In the adult Quaking mutant, there is an increase in some polysialogangliosides (GT1 and Gq) and a 50% decrease in BM1 content. Thus, the latter ganglioside, which is a constituent of mature myelin, could be linked to one of the late steps of the myelination process. A novel ganglioside ALG1, which appears during the postnatal development of brain, has been isolated and purified; it contains an alkali labile linkage and after alkaline treatment yields GT1b. Comparison between normal Mice and Quaking mutants does not show any significant quantitative differences, under our conditions. At the stage at which it appears, it could be linked to steps of brain maturation other than myelimation.

[Mouse brain gangliosides during development: demonstration of a new ganglioside]. / Etude des gangliosides dans le cerveau de souris au cours de sa maturation: mise en évidence d'un nolveau ganglioside

The study of gangliosides as a function of age indicates that four of the main components GD1a (G3), GD1b (G2), GT1 (G1) and GQ (G0) are present at birth. They increase with age. On thin-layer chromatography, GD1a seems to be maximum at 18 days and GD1b continues to increase. GM1 increases also from birth to adult age. A new ganglioside has been detected in Mouse brain during its development. Not detected 5 days after birth, it is present at 18 days and in maximal quantity at adult age. This compound does not seem to be correlated to myelination process.

Plasma galactocerebrosides in multiple sclerosis.

Plasma cerebrosides were examined in 12 cases of multiple sclerosis which were compared to normal controls and patients with cerebrovascular accidents. A screening was performed so as to select patients with levels above to normal by means of thin-layer chromatography of the lipid extract. Glucose seems to be the only hexose to be found normally in plasma cerebrosides. The presence of galactocerebrosides may be a biological test for demyelination, as their presence seems to be related to the evolutionary state of multiple sclerosis. In a severe cerebrovascular accident, galactocerebrosides were also found.