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Biomedical subjects

G Vincendon

Publications and source records attributed to G Vincendon.

At least 109 records · Page 6Linked to original sources
PubMed1981

Specific and artefactual cellular localizations of S 100 protein: an astrocyte marker in rat cerebellum.

Immunohistological techniques with specific antisera have been used to reinvestigate the problem of cellular localization of the neurospecific protein S100. In adult rat cerebellum, this protein is exclusively localized in astrocytes as shown by revealing in the same tissue secretion S100 protein and an oligodendrocyte marker, the isoenzyme II of carbonic anhydrase. The exclusive astroglial localization of S100 protein was confirmed by immuno-electron microscopy. A number of technical artefacts which may be at the origin of the claimed localization of S100 protein in neuronal cytoplasm and nuclei were also determined and described.

Animals↗
PubMed1981

A biochemical and immunohistological study of S100 protein in developing rat cerebellum.

Specific immune sera, one directed against S100 protein and one against glial fibrillary acidic protein (both proteins are specific astrocytic markers in rat cerebellum), were used in immunohistological methods to follow the formation and maturation of astrocytes during the postnatal development of rat cerebellum. Throughout development, S100 protein is detected only in astrocytes. Immunofluorescent Golgi epithelial cells and other astrocytes are detected in the cerebellum of newborn rat, their number increases rapidly between birth and the 10th postnatal day and then more slowly until the end of the 3rd week. In contrast, the increase in S100 protein level, measured in cerebellar homogenates by radioimmunoassay, was small until the 10th postnatal day. The greater accumulation subsequently found corresponds to an increase in the content of each astrocyte during the process of maturation.

Aging↗
PubMed1981

[Determination of proteinuria in children: changes in results according to the methods used (author's transl)].

Five methods for determination of proteinuria are compared : gravimetry, colorimetry (bromocresol green, Biuret test, Lowry's test), opacimetry (sulfosalicylic acid). Determinations were performed on normal urine, overloaded with albumin or gammaglobulins or on abnormal urine, after varying several parameters (pH, osmolarity, glucose, fructose, red blood cells, hemoglobin. leukocytes, germs). Some methods give non linear results depending on the concentrations (gravimetry, sulfosalicylic acid, bromocresol green). Some systematically give over-results (Biuret test, Lowry's test). Some almost exclusively determine albumin levels (bromocresol green, sulfosalicylic acid). In some, results are altered by glucose or fructose (Biuret, Lowry) or by red blood cells (Biuret, Lowry, sulfosalicylic acid). None of the tested methods can be used as a reference method. The method using sulfosalicylic acid is suitable for routine determination; however, results should be interpreted according to the parameters mentioned above.

Albuminuria↗
PubMed1980

Carbonic anhydrase: an ultrastructural study in rat cerebellum.

The cellular and intracellular distribution of carbonic anhydrase isozyme II in rat cerebellum has been investigated with the electron microscope by the indirect antibody immunohistochemical technique. Unequivocal evidence is presented supporting the view that this enzyme is exclusively localized in oligodendrocytes. Myelin does not appear to contain detectable amounts of carbonic anhydrase though it is present in oligodendrocyte processes and in the layer of oligodendrocyte cytoplasm frequently seen to coat the external surface of myelinated fibres. The immune precipitate is found to be confined to the cytosol and the cytosolic surfaces of intracellular membranes. The data are discussed in relation to the possible function of the enzyme and the role of oligodendrocytes in the central nervous system.

Animals↗
PubMed1980

An ultrastructural immunocytochemical study of nerve-specific protein in rat cerebellum.

The ultrastructural localization of the neuron-specific enolase (14-3-2 protein) has been investigated in the cerebellum of the adult rat using the indirect antibody immunohistochemical method. The protein was found exclusively in neurons: perikaryal cytoplasm, axons and dendrites were labelled while nuclei were not. Reaction product was found to be attached to intracytoplasmic membranes, the surface membranes of mitochondria and microtubules in addition to its dispersion as a flocculent material throughout the cytoplasm. All classes of cerebellar neurons were found to be labelled though large variations in the level of labelling between different types of neuron were noted. Purkinje cells appeared to have a much lower cytoplasmic concentration of this protein than other neurons.

Animals↗
PubMed1980

Astrocyte and oligodendrocyte distribution in adult rat cerebellum: an immunohistological study.

The distribution of the different types of glial cell in adult rat cerebellar cortex and in the underlying white matter was studied by immunohistology with a specific immune serum raised against form II of carbonic anhydrase, a specific marker for oligodendrocytes in rat cerebellum and an immune serum raised against glial fibrillary acidic protein, a specific astrocyte marker. The cellular specificity of each marker was confirmed by experiments in which the two antigens were revealed in the same cerebellar section. The unequivocal identification, with the optical microscope, of the different glial cell types allowed also a tentative estimation of the number of oligodendrocytes and astrocytes, in relation to Purkinje cells.

Animals↗
PubMed1980

Transient concanavalin A-binding glycoproteins of the parallel fibres of the developing rat cerebellum: evidence for the destruction of their glycans.

The lifetime of the glycoprotein glycans of the rat cerebellum was followed in the 2nd and 3rd weeks of postnatal age, after injection of labelled glucosamine. It appears that a particular class of glycans binding to Concanavalin A synthesized at an early age has a short lifetime. These results indicate that the glycans of the concanavalin A-binding glycoproteins abundant on the newly formed parallel fibres are rapidly degraded between the 14th and the 18th postnatal day.

Aging↗
PubMed1979

Double labeling immunohistochemical technique provides evidence of the specificity of glial cell markers.

Sequential treatment of rat cerebellar slices with two antisera, each specific for a different glial cell marker, revealed, by indirect immunofluroescence combined with the immunoperoxidase method on the same tissue section, that carbonic anhydrase isoenzyme II (CA II) is exclusively localized in oligodendrocytes while the glial fibrillary acidic protein (GFA) is, as well established, a specific marker for astrocytes.

Animals↗
PubMed1979

[Arylsulfatase A and sphingomyelinase activities in the normal sciatic nerve of the rat, and in proximal and distal fragments].

We measured the protein, arylsulfatase A and sphingomyelinase activities in the total normal rat sciatic nerve and in the proximal and distal stumps. The protein level of the whole sciatic nerve (about 8 % of fresh weight) is similar to the levels of the stumps. Arylsulfatase A activity, in the total sciatic nerve as well as in the stumps is more important by gram of fresh weight than the sphingomyelinase activity. Both enzymes activities, by gram of fresh weight, are more important in the proximal stumps than in the distal ones.

Animals↗
PubMed1978

Postnatal development of rat cerebellum: massive and transient accumulation of concanavalin A binding glycoproteins in parallel fiber axolemma.

Modifications of protein-bound sugars during postnatal development of rat cerebellum were studied. Glycoprotein-bound mannose accumulates, in the particulate fractions, at an earlier age than the bulk of glycoprotein sugar. This corresponds to a transient and massive accumulation of glycoproteins which bind to Concanavalin A (Con A). These glycoproteins were localized by using fluorescent Con A and the horseradish peroxidase-Con A method. Cerebellar white matter and the molecular layer bind massive amounts of Con A. The binding in the molecular layer is transient. It follows the same time course as the Con A-binding glycoproteins of particulate fractions, and it is largely confined to the axolemma of parallel fibers. Only growing or newly formed parallel fibers bind Con A. The disappearance of the binding is simultaneous with the maturation of parallel fibers and their synapse formation. These phenomena can be related to fiber growth and maturation and, also, to synapse formation. The possibility of a specific role of Con A-binding glycoproteins is discussed.

Age Factors↗
PubMed1977

Synaptosomal plasma membrane glycoproteins. II. Isolation of fucosyl-glycoproteins by affinity chromatography on the Ulex europeus lectin specific for L-fucose.

After solubilization in sodium dodecyl sulphate, almost 90% of synaptosomal plasma membrane glycoproteins were separated from the bulk of synaptosomal plasma membrane proteins by sequential affinity chromatography on two immobilized lectins: concanavalin A and the Ulex europeus lectin specific for L-fucose. Four fractions were obtained and their sugar composition and electrophoretic patterns were determined. Fucosyl-glycoproteins contain more than 26% of protein and 85% of the protein-bound sugar of synaptosomal plasma membrane; hence they constitute a major class of glycoproteins in these membranes. The presence of some glucose in glycoproteins fractions obtained after affinity chromatography on the two lectins suggests that this sugar could be a structural component of some brain glycoproteins. Polyacrylamide gel electrophoresis revealed at least 28 major bands in fucosylglycoprotein fractions, and 11 in other fractions. Several of these major bands appear to contain more than one glycoprotein each. This heterogeneity appears to be mostly the result of the heterogeneity of the neuronal population in the central nervous system. Microheterogeneity of glycoprotein sugar chains and possible contamination of synaptosomal plasma membranes play, in our opinion, only a minor role.

Animals↗