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G Roussel

Publications and source records attributed to G Roussel.

At least 55 records · Page 3Linked to original sources
PubMed1986

A specific immunological probe for the major myelin proteolipid. Confirmation of a deletion in DM-20.

Major myelin proteolipid (MMPL, also called PLP) and DM-20 are the two major intrinsic membrane proteins of CNS myelin. A specific immunological probe was obtained for MMPL by raising antibodies against the synthetic tridecapeptide 117-129 of MMPL. Antibodies against this peptide reacted with the MMPL but did not cross react with DM-20, while both proteolipids had been shown previously to be recognized by antibodies directed against the C-terminal hexapeptide of MMPL. This is in accordance with previous findings showing that DM-20 differs only from MMPL by a deletion of residues 100-140 (+/- few units). Furthermore, this site-specific immunological probe also recognizes MMPL in its native form in oligodendrocytes in primary glial cell cultures.

Amino Acid Sequence↗
PubMed1986

A procedure for long-term culture of oligodendrocytes.

A procedure for long-term culture of oligodendrocytes is described, the starting material being 20-day-old primary mixed cultures of newborn rat brain. Cells were first incubated in a serum-free medium for 48 h before they were subcultured on poly-L-lysine coated plastic dishes. After this treatment, the oligodendrocytes developed well in Waymouth medium containing 10% (v/v) calf serum, while most of the astrocytes died. At 13 days in subculture more than 90% of the cells were identified as oligodendrocytes; the criteria for oligodendrocytes were based on their immunoreactivity to antisera against W1 Wolfgram protein, myelin basic proteins and the synthetic C-terminal hexapeptide of the major myelin proteolipid. At 13 and 19 days astrocytes were present, 7% and 20% respectively. The culture system described here may be useful to study the biochemical and immunological aspects of the oligodendrocytes.

Animals↗
PubMed1986

UDPgalactose:ceramide galactosyltransferase of rat brain: a new method of purification and production of specific antibodies.

A new method for purification of UDPgalactose:ceramide galactosyltransferase (EC 2.4.1.45) is described. The principal steps involved solvent extraction at -70 degrees C, Triton X-100 extraction, and DEAE-Sephadex and Blue Sepharose chromatography. The active configuration of the enzyme was stabilized by phospholipids and a rapid loss of enzymatic activity was observed after removal of these lipids. The inactive enzyme could be fully reactivated in the presence of brain phospholipids dispersed in a Triton X-100-containing buffer. The purified enzyme preparation showed two major components by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate with apparent molecular weights of 50-70,000. The 53,000-dalton protein was isolated by preparative gel electrophoresis in the presence of sodium dodecyl sulfate and used to produce antibodies against UDPgalactose:ceramide galactosyltransferase.

Animals↗
PubMed1986

Comparison of monoclonal antibodies and tritiated ligands for estrogen receptor assays in 241 breast cancer cytosols.

Estrogen receptor determinations have been performed on 241 cytosols from 160 breast cancer tumors using both radioactive ligands ([3H])-estradiol, [3H]R2858) and monoclonal antibodies (Abbott ER-EIA Kit) in order to compare the two methods and to evaluate the clinical usefulness of the new immunological, simplified assay. Intra- and interassay reproducibility of the enzyme immunoassay (EIA) method was studied during a 6-month period on 35 standard curves with 4 different batches of monoclonal antibodies. Intraassay coefficients of variation studied on duplicates were smaller than 5% in most cases. Interassay reproducibility of the curves showed coefficients of variation lower than 10% except for standard 0 and 5 fmol/ml. Seven different control specimens provided by Abbott Laboratories were assayed with the EIA method, with interassay coefficients of variation from 1.7% [233.4 +/- 4 (SD) fmol/ml] to 18.2% [18.5 +/- 3.3 fmol/ml]. Pooled cytosols used as control for the dextran coated charcoal method had interassay variation coefficients between 3.8 and 11.4%. Reproducibility has been studied on clinical specimens assayed twice at two different periods with either EIA or dextran coated charcoal methods. Slopes obtained were 1.05 and 0.96, respectively. A good stability of EIA results was obtained with protein concentrations in the range 4-0.15 mg/ml cytosol. No significant effects of dithiothreitol or monothioglycerol (1 mM) on EIA and dextran coated charcoal assay were observed. Eighty breast cancer cytosols were assayed with both EIA and Scatchard analysis. The slope of the regression curve obtained was 1.04 (r = 0.963). Cytosols were assayed by EIA and by a saturating concentration of tritiated ligand (5 nM). With 153 cytosols the EIA/5 nM slope was 1.34 (r = 0.978). This slope can be compared with the slope Scatchard/5 nM obtained with 90 cytosols: 1.29 (r = 0.985). Absence of cross-reactivity of monoclonal ER antibodies with progesterone receptor was observed.

Antibodies, Monoclonal↗
PubMed1985

Stereospecific effects of the alpha-aminoadipic acid on the retina: a morphological and electrophysiological study.

In both frog and chicken an intravitreal injection of the dextrorotatory (D)-isomer of alpha-aminoadipic acid (alpha-aaa) leads to a progressive disappearance of the ERG b-wave without affecting a and c components. Tectal evoked potentials (TEP) are no longer recorded. These physiological effects are concomitant with a specific glial cell damage, without any apparent damage to neurons. The levorotatory (L)-isomer at low concentrations is more gliotoxic than the D-isomer, the ERG b-wave is suppressed, while the amplitude of both a and c components is increased. TEPs are always recorded, i.e., a visual message is still generated in the retina and transmitted to the optic tectum when the Müller cells have been damaged and the b-wave is abolished. At higher concentrations the L-isomer suppresses TEPs and damages both glial and neuronal cells. Thus alpha-aaa appears to be a good tool for analyzing ERG components, especially subcomponents of the c-wave.

2-Aminoadipic Acid↗
PubMed1985

Precursor cells of oligodendrocytes in rat primary cultures.

In monolayer primary cultures of brain from newborn rats, which contain astrocytes and oligodendrocytes, a new morphological cell type (flat black cells) was observed. Microphotographs of different areas of the monolayer, taken every 30 min, showed that these flat black cells can divide and that they undergo morphological transformation in vitro. They give rise to oligodendrocytes which were identified by their characteristics morphology but also by their content of W1 Wolfgram protein. These findings suggest that the flat black cells are precursors for oligodendrocytes, in culture.

Animals↗
PubMed1985

Site-specific antibodies to rat myelin proteolipids directed against the C-terminal hexapeptide.

A site-specific antiserum against the rat myelin proteolipids was produced in rabbits by injection of a synthetic polypeptide composed of the C-terminal amino acids of the proteolipid sequence. The immunogenic hexapeptide H-Gly-Arg-Gly-Thr-Lys-Phe-OH was coupled to chicken egg-albumin with dimethylsuberimidate. Antibodies specific for this peptide reacted with the 2 myelin proteolipid protein bands after SDS polyacrylamide gel electrophoresis and electrophoretic transfer onto nitrocellulose. Immunocytochemical investigations with this anti-peptide antiserum showed that the Golgi complexes of the oligodendrocytes were highly labeled as noted previously with multivalent antibodies. Labeling of vesicles and discontinuous staining of the plasmalemma were also observed in the most actively myelinating oligodendrocytes. In contrast to previous results, the major dense line was free of staining; this may indicate that at this site the C-terminal hexapeptide is inaccessible to these antibodies and perhaps buried in the lipid bilayer, in disagreement with the proposed organization of the myelin proteolipid in the myelin membrane.

Amino Acid Sequence↗
PubMed1985

Isolation and immunohistochemical localization of a lectin-like molecule from the rat cerebellum.

A lectin with a mannose specificity was isolated from the cerebellum of young rats. The method of purification was based on the observation that during homogenization of the tissue, the lectin binds to a class of mannose-rich glycoproteins highly insoluble in Triton X-100. Sequential extractions in saline buffer devoid of, then containing, 0.5% Triton X-100 allowed the elimination of a great part of other proteins. Using the same buffer containing 0.5 M mannose, a specific class of protein can be solubilized. This fraction was enriched by affinity adsorption on insolubilized mannose-rich glycoproteins followed by specific detachment with mannose. One of the protein subunits, of molecular weight (MW) 130,000, was isolated by preparative gel electrophoresis. Upon re-electrophoresis, this compound gives two bands of MW 65,000 and 130,000, which appear to be a monomer and a dimer of a molecule called R1. Antibodies were raised against R1 which react with the monomer and the dimer and not against other proteins of the rat cerebellum. The immunohistochemical localization of this lectin was performed in cerebella of 20-day-old rats. The antigen is concentrated in endothelial cells and in large and intermediate size neurons (Purkinje, Golgi, basket and deep nuclei neurons). Granule cell bodies are lightly stained and no label at all was found in glial cells. At the level of electron microscopy, the antigen was found to be very concentrated in multivesicular bodies and lysosomes of large neurons, on parts of the endoplasmic reticulum, on some mitochondrial outer membranes and on the plasma membrane of the dendrites. The possible role of this lectin in cerebella of young rats is discussed in relation to its interaction with a specific class of mannose-rich glycoproteins.

Animals↗
PubMed1985

Immunohistochemical localization of a lectin-like molecule, R1, during the postnatal development of the rat cerebellum.

The immunohistochemical localization of an endogenous lectin R1 isolated from the rat cerebellum was studied during its postnatal development. The lectin is present in the cerebellum from birth to adulthood, essentially in lysosomes, multivesicular bodies, and parts of the endoplasmic reticulum, principally of large and intermediate size neurons. During the period of massive synaptogenesis in the molecular layer, there is a sprouting of R1 in some distal dendrites of Purkinje cells. The lectin appears to be particularly concentrated on their plasma membranes, in coated pits, in coated vesicles, multivesicular bodies and lysosomes. At the same period, in cerebella of rats treated with chloroquine (an inhibitor of lysosomal function), both the lectin and mannose-rich glycoproteins of newly formed parallel fibres (able to bind specifically this lectin) are found in the same non-functional lysosomes of Purkinje cells. It is thus suggested that both this lectin (with a high-affinity for the glycans of the mannose-rich glycoproteins of the membrane of the newly formed parallel fibres) and these glycoproteins could be the recognition molecules allowing a specific contact between parallel fibres and Purkinje cells at the period of synaptogenesis.

Animals↗
PubMed1985

[Determination of estrogen receptors in 160 breast tumors using monoclonal antibodies: comparison of Abbott's immunoenzymatic method with the carbon dextran method].

Estrogen receptor determinations were performed on 241 cytosols from 160 breast cancer tumors, using both dextran coated charcoal method (D.C.C.) and monoclonal antibodies (Abbott's ER-EIA kit) in order to compare the two methods, and to evaluate the clinical usefulness of this new immunological simplified assay. Intra- and inter-assay reproducibility were studied during a six month period. Intra-assay of both methods were lower than 5%. Inter-assay variation coefficients of ER-EIA studied on 35 standard curves varied from 12.5% (standard: 0) to 6.7% (standard: 250 fmoles/ml). ER determination of 80 human breast cancers were performed both by EIA and Scatchard analysis. The regression curve obtained was (EIA) = 1.04 (Scatchard) + 21 fmoles/mg of proteins (r = 0.963). With 153 breast cancer cytosols whose volume was too small for multipoint Scatchard analysis, EIA results were compared to results obtained by a "near saturating" concentration of tritiated ligand (5 nM). The regression curve obtained was (EIA) = 1.34 (5nM) + 5 fmoles/mg proteins (r = 0.978). These results can be compared with those obtained between Scatchard and 5 nM: (Scatchard) = 1.29 (5nM) - 9 fmoles/mg proteins (r = 0.985). Reproducibility was studied on clinical specimens assayed at two different periods during the clinical evaluation. Regression curves obtained were (2nd assay) = 1.05 (1st assay) - 5.5 fmoles/mg proteins for EIA, and (2nd assay) = 0.96 (1st assay) + 9 fmoles/mg proteins for DCC method. EIA assay presented an high stability for protein concentrations very low, up to 0.2 mg/ml. Finally, a very good correlation was obtained between ER-EIA and DCC method, and ER-EIA seemed specially well fitted to small tumors.

Adult↗
PubMed1983

Detection of Wolfgram W1 protein, myelin basic proteins and proteolipids in cultured oligodendrocytes by the electro-immunoblotting method.

Oligodendrocytes, mechanically obtained from primary cultures of newborn rat brain, were investigated by a sensitive electro-immunoblotting method for the presence of the characteristic myelin proteins: Wolfgram W1 protein, basic proteins and proteolipids. These three major myelin protein types were detectable from the 20th to the 40th day in culture. The present biochemical findings are in accordance with previous immunohistochemical data and provide additional evidence that oligodendrocytes in culture are capable of synthesizing every myelin and oligodendrocyte marker found in vivo, in the absence of neurones.

Animals↗
PubMed1983

Immunocytochemical demonstration of the transport of myelin proteolipids through the Golgi apparatus.

Purified antibodies directed against myelin proteolipids were isolated by affinity chromatography of whole serum obtained from rabbits inoculated with myelin. These antibodies were specific for light, medium and dark oligodendrocytes. Astrocytes, neurons and their processes were not reactive. Immunocytochemical investigations showed that the membranes of the Golgi complex are highly labeled by these antibodies. Diffuse cytoplasmic labeling was only observed on the light and medium oligodendrocytes and was absent from the dark types. Vesicles possessing a punctate staining were detected in the vicinity of the Golgi complex and the oligodendroglial membrane. A discontinuous labeling of the plasmalemma appears to be characteristic of the actively myelinating light and medium oligodendrocytes. In compact myelin sheaths positive immunostaining was only detected at the dense line. The immunocytochemical localization of the myelin proteolipids in the oligodendrocytes is in accordance with previously published biochemical data.

Animals↗
PubMed1983

An immunohistochemical study of two myelin-specific proteins in enriched oligodendroglial cell cultures combined with an autoradiographic investigation using [3H]thymidine.

The aim of the present work was to examine the possible relationship between proliferation and expression of 2 myelin specific proteins in cultured oligodendroglial cells. Mixed cultures of glial cells, from newborn rat brain, containing astroglia and oligodendroglia were grown in 2 different culture media, minimum Eagle's medium and Waymouth's medium both supplemented with 10% calf serum in presence or absence of adult rat brain soluble extract. The proliferative activity of the cells was followed over a 28-day period by autoradiography after radioactive thymidine incorporation. It was found that in cultures grown in Waymouth's medium the proportion of oligodendroglial cells was higher and that proliferation was more active than in minimum Eagle's medium. Addition of brain extract elicited a stimulation of the proliferation of the cells in the 2 basal media. Under all conditions W1 protein appeared earlier than MBP by immunofluorescent visualization. Some oligodendroglial cells synthesizing W1 protein were still able to proliferate. MBP appears to be a marker of a later stage of cell maturation since very few MBP-positive cells incorporated tritiated thymidine. More cells contained MBP in the presence of brain extract. These results suggest that oligodendroglial cell maturation proceeds by steps, the step of W1 protein expression is compatible with proliferation while that of MBP expression appears at the end of the proliferation phase.

Animals↗
PubMed1983

Arguments in favour of endocytosis of glycoprotein components of the membranes of parallel fibers by Purkinje cells during the development of the rat cerebellum.

Chloroquine (a drug known to induce a dysfunction of lysosomes) was used to study the behavior of Concanavalin A binding glycoproteins located on the axolemma of parallel fibers in young rat cerebella, and abundant on these membranes at a period preceding synaptogenesis with the dendrites of Purkinje cells. Chloroquine induces in Purkinje cells a large accumulation of grains consisting of membrane whorls in lysosomes. These grains stain for Concanavalin A, and do not stain either for a mitochondrial marker (aspartate aminotransferase mitochondrial isoenzyme) or for a marker of the Purkinje cell internal membrane (PSG). It is suggested that the material accumulating in the Purkinje cells under the effect of chloroquine comes from the parallel fibers. Together with the observation that alpha-D-mannosidase (involved in the degradation of these glycoproteins) is exclusively located inside Purkinje cells, these results provide a firm indication that this material enters the Purkinje cells through pinocytosis. The absence of ATPase activity (ATPase is a glycoprotein plasma membrane marker highly concentrated on parallel fibers) within these grains suggested that not all the components of these membranes are pinocytosed, but that the process is specific for certain molecules. These results are compatible with the ultrastructural observations of others, and support the arguments in favour of the pinocytosis phenomenon being one of the first steps of synapse formation. The observed specificity of pinocytosis for certain molecules suggests that a receptor-mediated recognition of some glycans of glycoproteins is the preliminary event in the establishment of synapses.

Adenosine Triphosphatases↗
PubMed1983

Immunohistochemical study with an anti-myelin serum. A marker for all glial cells except 'dark' oligodendrocytes.

The usefulness of an anti-myelin antiserum as a possible marker for glial cells and related structures was investigated using rat brain. As expected, the myelin fibers were heavily stained but the neuronal cells and their processes were unreactive. The oligodendrocytes, identified on electron microscopy, revealed labelling of only the light and medium types, but not the dark cells. These results indicate that the suggested morphological classification of oligodendrocytes may be based on varying amounts of myelin antigen synthesis. Astrocytes from all areas, Golgi epithelial cells, Bergmann fibers and some subependymal cells also reacted with this anti-myelin antiserum but the staining was abolished completely by preabsorption with kidney powder. In contrast, the myelin fibers and the light and medium oligodendrocytes could still be labelled. We conclude that this anti-myelin antiserum should prove useful in studies of oligodendrocytes in the central nervous system.

Animals↗
PubMed1983

Immunohistochemical localization of alpha-mannosidase during postnatal development of the rat cerebellum.

The localization of alpha-D-mannosidase in the rat cerebellum was studied by using indirect immunohistochemistry at both optical and electron microscopic levels. In the adult the enzyme is particularly concentrated in the dendrites and cell bodies of Purkinje cells, basket cells, and Golgi neurons in the cerebellar cortex and in the cytoplasm and dendrites of deep nuclei neurons. The cytoplasm of granule cells is poorly stained, whereas parallel fibers, white matter, Bergman fibers, and Golgi epitheloid cell perikarya show virtually no staining. Electron microscopy suggests that most of the staining is found in the cytosol, although some staining is found in the postsynaptic densities of the synapses between parallel fibers and Purkinje dendrites. The pattern of staining was followed throughout the postnatal development of the rat cerebellum. At bith an intense and diffuse staining is found in all cells except those of the external germinative layer. At the 6th postnatal day, Purkinje cell bodies and apical cones are strongly labeled. From the 13th day on the pattern is very similar to that found in the adult. However, at the 18th postnatal day (when compared with the other structures), the staining of Purkinje cell dendrites seems to be higher than at all other ages. These data are correlated with biochemical studies and discussed in relation to the possible role of this enzyme during the postnatal development of the rat cerebellum.

Acetylglucosaminidase↗
PubMed1983

[Long-term results of a trial of short-term chemotherapy. French study 6.9.12].

The relapse rate after short course chemotherapy is usually assessed by cases that are available for analysis, with a delay which rarely exceeds 3 years from the time of instituting therapy. This level may be disputed if too many are lost to follow up or non-compliers appearing late. To understand the true failure rate we strove to trace every patient in a trial carried out between 1969 and 1973, consisting of three groups of patients treated with the same chemotherapy: Isoniazid (450 mg/day), Rifampicin (600 mg/day) given every day but for differing durations: 6 months (Group A), 9 months (Group B), 12 months (Group C), with either daily Ethambutol or Streptomycin in addition for the first three months. Amongst the 356 patients in the trial 86 were eliminated for failure to comply with the protocol, either due to a mishap or change of treatment. Amongst the 270 remaining patients, 248 were traced with a mean delay of post-therapy follow up of 101 months for patients still living and of 72 months for patients who had died in the intervening period, but of non-tuberculous disease. In the 242 old patients whose disease could be evaluated, the number of bacteriological relapses was 4/81 (6.2 %) in group A, and 2/85 (2.3 %) in group B and 2/76 (2.6 %) in group C. There was no significant differences between the groups. From these results it is seen that the Isoniazid/Rifampicin combination given daily for 6 months is a powerful combination with few failures. Maintaining such chemotherapy for 12 months does not seem to yield substantial gains. In conclusion nine months of chemotherapy with this regime offers a sufficiently ample guarantee of cure.

Antitubercular Agents↗