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G Roussel

Publications and source records attributed to G Roussel.

At least 37 records · Page 2Linked to original sources
PubMed1991

Proteolipid DM-20 predominates over PLP in peripheral nervous system.

The major central nervous system (CNS) myelin proteolipid (PLP) is also expressed in the peripheral nervous system (PNS). This paper gives evidence that DM-20, an isoform of PLP, also occurs in rat sciatic nerves, where, in contrast to what is seen in CNS myelin, it predominates over PLP. This conclusion was reached on the basis of results obtained by immunoblot analysis of a crude proteolipid extract from adult peripheral nerve with two site-specific anti-proteolipid (PLP and DM-20) antibodies. This finding was further corroborated by characterization of the products obtained by Polymerase Chain Reaction (PCR) amplification of cDNAs synthesized from total RNA of 14-day-old sciatic nerves. The significance of the occurrence of these proteolipids in PNS remains obscure.

Amino Acid Sequence↗
PubMed1991

In situ localization of NF-H neurofilament subunit mRNAs in rat brain.

The expression of NF-H neurofilament subunit mRNAs was investigated in the rat brain at different ontogenic stages. The levels of NF-H mRNAs vary 15-fold among brain regions with the highest level in the brainstem. In situ localization studies revealed that the NF-H mRNAs are mainly concentrated in the brainstem motoneuron nuclei. By increasing the sensitivity of the hybridization method, NF-H mRNAs could also be localized in neurons present in the cortex, thalamus and hippocampus areas. Minor amounts of NF-H mRNAs were already detected at 17-day embryonic stages.

Animals↗
PubMed1991

[Interpretation of the values of urinary cotinine in smokers and non-smokers].

The values of urinary cotinine measured using high performance liquid chromatography in 125 adults (44 men and 81 women) were compared with the degree of intoxication and/or exposure to tobacco experienced over six consecutive days by auto-questionnaire. The subjects were classified in 6 groups: non exposed non smokers and non smokers exposed for less than one hour (1, n = 16); non smokers exposed for between 1 and 10 hours (2, n = 26); non smokers exposed for more than 10 hours and less than 30 hours (3, n = 33); non smokers exposed for more than 30 hours (4, n = 13); smokers smoking less than 20 cigarettes per day (5, n = 16); smokers smoking 20 cigarettes or more per day (6, n = 21). The measurements were made on urine specimens from the first morning (fraction F1), from the day and night (F2) and those of the second morning (F3). The results were expressed in micrograms/fraction and were as follows: Group 1: 37.3 (F1); 149.5 (F2); 26.8 (F3)--Group 2: 81.2; 234.1; 75.4--Group 3: 121.1; 383.1; 80.7--Group 4: 98.8; 253.7; 117.2--Group 5: 206.9; 773.8; 188--Group 6: 483.1; 1908.2; 431.3. Cotinine was found in all individuals whether they declared that they were exposed or non exposed (with the exception of a single person amongs the latter). In spite of a certain amount of overlapping between the results of the individuals in groups 4 and 5, the values obtained enabled a differentiation between the degrees of tobacco absorption.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Immunoradiometric assay of pS2 protein in breast cancer cytosols.

We studied the ELSA-pS2 immunoradiometric kit (CIS Bio International) for pS2 protein assay in breast cancer cytosols according to classic validation methods. In addition, we studied correlations between pS2, steroid receptors, and cathepsin-D assays. Repeatability (CV = 1.5% to 4.8%) and reproducibility (CV = 1.6% to 4.9%) were good. The results were linearly related to pS2 concentrations between 205 and 2200 ng/L; the detection limit was 40 ng/L. The accuracy of the assay was measured by assessing recovery; analytical recoveries were near 100% throughout the standard curve. The use of different compounds for cytosol preparation (Tris 10 mmol/L or phosphate 25 mmol/L, KCl 0.4 mol/L, bovine serum albumin 1 g/L) had no effect on pS2 results. pS2 was assayed in breast tumor cytosols from 197 postmenopausal and 92 premenopausal patients. The mean value was 24 micrograms/g of protein; the median and 25th and 75th percentiles were 6, 1, and 23 micrograms/g protein, respectively. We observed a relation between concentrations of pS2 and those of estrogen and progesterone receptors, but there was no relationship between the concentrations of pS2 and cathepsin-D.

Breast Neoplasms↗
PubMed1990

Penta- and hexadienoic acid derivatives: a novel series of 5-lipoxygenase inhibitors.

The synthesis of a series of pentadienoic and hexadienoic acid derivatives is reported. These compounds were tested as inhibitors of 5-lipoxygenase (5 LO) and cyclooxygenase (CO) in vitro and as inhibitors of arachidonic acid (AA) induced ear edema in mice in vivo. Their potency is compared with that of the standard inhibitors nafazatrom, BW 755C, NDGA, KME4, quercetine, and L 652,243. The most potent compound in vivo, diethyl 2-hydroxy-5-(ethylthio)-2(Z),4(Z)-hexadienedioate (20) inhibited AA-induced ear edema when administered topically or orally, with an ED50 value of 0.01 mg/ear and 20 mg/kg, respectively. Among the standard compounds tested, L 652,243 was the most active compound in this test with an ED50 value of 0.01 mg/ear and 1 mg/kg po, but unlike this compound, 20 is a selective inhibitor of 5-LO (IC50 = 2 microM) without any significant activity against CO (IC50 greater than 50 microM). Most of the other compounds in this series are also selective 5-LO inhibitors.

Administration, Topical↗
PubMed1989

Immunological and physiological analysis of human breast cancer progesterone receptor heterogeneity, following KCl dissociation and size exclusion chromatography.

Progesterone receptor (PR) levels were determined in 69 human breast cancer specimens by both radioligand assay (RLA) and enzyme immunoassay (EIA). These methods did not detect the same number of sites, and for each tumor there was a constant ratio between epitopes and PR-binding sites corresponding to 1/4, 2/4, ... 8/4. High performance size exclusion chromatography was performed to separate the various PR isoforms, and the ability of these isoforms to interact with the monoclonal antibodies was assessed. Determination of PR in the chromatographic fractions by EIA and RLA showed that the various isoforms isolated by chromatography presented variable quantities of steroid-binding sites and epitopes, thus confirming the differences observed in the cytosol assays. The dissociation of molybdate-stabilized PR by KCl and measurement by RLA and EIA of the isoforms obtained showed two different types of chromatographic patterns, particularly in the 8S polymeric form where the monoclonal antibodies appeared to detect mainly the heavier 8S fraction, which may correspond to the 8S-B form of the progesterone receptor. The monoclonal antibodies also detected an intermediate PR polymeric form (236 kDa) which was not always detected by the tritiated ligand. Our results suggest that breast cancer PR exhibit a marked molecular heterogeneity which may partially explain the differences in response to hormonal therapy, particularly for tumors with high receptor levels which nonetheless fail to respond to treatment.

Antibodies, Monoclonal↗
PubMed1989

Elimination of caffeine interference in HPLC determination of urinary nicotine and cotinine.

We report an analytical reversed-phase liquid-chromatographic procedure for quantifying nicotine and cotinine in urine, taking into account the presence of interfering caffeine frequently encountered in such specimens. These analytes are extracted from the alkalinized urine with chloroform. After evaporation of the chloroform, the residue is dissolved in methanol and injected into a chromatographic C18 column. Extraction recoveries averaged 80% to 97%. Chromatographic conditions were investigated to obviate caffeine interference. The proposed eluent mobile phase is a polar mixture of water, acetonitrile, methanol, and a pH 4 acetoacetate buffer (65/2/29/4 by vol) adjusted to pH 4.30 +/- 0.02 with triethylamine. High resolution and linearity were obtained for each analyte up to a concentration of 200 mg/L. The minimum detectable amount of each compound was 20 ng per injection, corresponding to 10 micrograms per liter of urine. Correlation with results of gas-liquid chromatography was excellent (r = 0.99). This simple, rapid procedure allows routine screening of tobacco exposure with acceptable precision: within- and between-run coefficients of variation were less than 2% and less than 5%, respectively.

Caffeine↗
PubMed1988

Steroid receptors analysis in human mammary tumors by isoelectric focusing in agarose.

A high resolution and quantitative method for isoelectric focusing has been developed to separate the isoforms of estrogen and progesterone receptors in human mammary tumor cytosols stabilized by sodium molybdate. Agarose gels (0.5%) were used. Six samples can be analyzed on one gel in about 2 h, and 35-microliters samples are sufficient to determine the estrogen receptor isoform pattern. The constant yields and the reproducibility of data allow a quantitative analysis of these receptors. Four estrogen receptor isoforms have been observed (pI 4.7, 5.5, 6, and 6.5), isoforms with pI 4.7 and 6.5 being present in all tumors. After incubation at 28 degrees C in high ionic strength, the comparison of isoelectric focusing and high-performance size exclusion chromatography patterns of estrogen receptor confirms the oligomeric structure of the pI 4.7 isoform and suggests a monomeric structure for the pI 6.5 isoform. Under the same conditions of analysis, only one progesterone receptor isoform has been detected with pI 4.7.

Aged↗
PubMed1988

Charge heterogeneity of human mammary tumor estrogen receptors. Relationship with a hormonal sensitivity tumor marker.

A high resolution quantitative method for estrogen receptor analysis has been elaborated using isoelectric focusing in 0.5% agarose gel, without any prior trypsin digestion. The 23 cytosols analyzed were stabilized by molybdate and prepared from human mammary tumors with progesterone receptors (PR + cytosols) or without (PR - cytosols). Progesterone receptor was used as a tumoral hormonal sensitivity marker. The estrogen receptors usually resolved as 4 isoform peaks of close isoelectric points. In PR - cytosols, the mean pI values were 4.7, 5.5, 6 and 6.5. Significant differences between the two cytosol populations were observed concerning pI 4.7 and 6.5 isoforms. In PR - cytosols, the pI 4.7 isoform occurred in greater proportions than in PR + cytosols, whereas lower proportions of pI 6.5 isoform were seen. The comparison between high performance size exclusion chromatography profiles and isoelectric focusing patterns, before and after cytosol incubation at 28 degrees C with KCl (0.4 M), confirmed an oligomer structure for the pI 4.7 isoform and suggested a monomer structure (Stokes radius 2.9 mm) for the pI 6.5 estrogen receptor isoform. The results indicated that isoelectric focusing analysis of estrogen receptors could be useful in the prediction of breast cancer hormonal sensitivity.

Aged↗
PubMed1988

A chemically defined medium for the culture of mature oligodendrocytes.

A new chemically defined medium consisting of equal parts of Dulbecco modified Eagle's and Ham's F-12 media supplemented with insulin, sodium selenite, putrescine, and D+ galactose, which allows the long-term survival of mature oligodendrocyte pure cultures, is described. Immunohistochemical staining has shown that over 90% of the cells become positive for myelin proteins shortly following subculture. Contaminating astrocytes (2%) do not survive in this medium. Biochemical data have indicated that these purified oligodendrocytes express 2'3'-cyclic nucleotide 3'-phosphohydrolase and UDP-galactose ceramide galactosyltransferase activities. Electron microscopical examination revealed that the oligodendrocytes were mostly of medium-dark type and appeared to be identical to cells cultured in serum-containing medium. The ability to maintain pure oligodendrocyte cultures in such a defined medium will allow investigations concerning exogenous and endogenous factors involved in oligodendrocyte metabolism.

2',3'-Cyclic Nucleotide 3'-Phosphodiesterase↗
PubMed1988

A morphological and biochemical study of the myelin-like membrane structures formed in cultures of pure oligodendrocytes.

This study reports the production of myelin-like membranes in oligodendrocyte subcultures derived from 20-day-old primary glial cell cultures of newborn rat brain. These multi-layered structures show a variable number of membrane turns; up to 10 concentric lamellae are found in 3- to 4-week-old subcultures. When they are compacted, alternate dense and intraperiodic lines with a periodicity of 11.2 nm are noticeable. The most typical myelin proteins were detected straight on the multi-lammellar structures by a gold immunocytochemical method. Subcellular fractions containing these myelin-like structures were isolated by ultracentrifugation on a discontinuous sucrose gradient. They were analysed by sodium dodecylsulfate-polyacrylamide gel electrophoresis and immunoblotting; UDP-galactose: ceramide galactosyltransferase and 2',3'-cyclic nucleotide 3'-phosphohydrolase activities were also measured. The results indicate that the multi-layered membrane profiles have many characteristics of the myelin found in vivo; nevertheless some differences were still apparent. Our data support the concept of the cultured oligodendrocytes expressing the intrinsic myelinogenic properties and possessing a basic developmental program of myelination, apparently in the absence of stimuli coming from other brain cells.

Animals↗
PubMed1988

UDPgalactose:ceramide galactosyltransferase in cultured oligodendrocytes: an enzymological and immunological study.

The developmental expression of UDPgalactose:ceramide galactosyltransferase (CGalT), an enzyme marker of one myelinogenic activity in nervous tissue, was studied in cultured oligodendrocytes. The activity of CGalT in cultures followed a characteristic pattern of developmental changes. In the primary cultures these changes could be represented by a biphasic curve with a maximum of enzymatic activity at about the 25th day in culture. After purifying the oligodendrocytes from the primary cultures and replating them in culture dishes, similar developmental changes of CGalT were observed. In the subcultures prepared from 20-day-old primary cultures the activity of CGalT per oligodendrocyte increased from 1.3 x 10(-6) nmol/hr on day 4 to 3.7 x -6 nmol/hr on day 21. Immunocytochemical studies with the antiserum against rat brain CGalT showed the presence of CGalT+ oligodendrocytes after 7 days in the primary culture (earliest time studied), later on the number of CGalT+ oligodendrocytes increased until 28 days (latest time examined). In the subcultures of purified oligodendrocytes the bulk of oligodendrocytes was stained by the anti-CGalT antibodies after 15 days. These results suggest that the initial expression of CGalT in oligodendroglial cultures involves an increase of the number of CGalT+ oligodendrocytes and of the amount of enzyme protein per cell.

Animals↗
PubMed1988

Immunological investigation of a 21-kilodalton cytosolic basic protein in rat brain.

A gamma-globulin fraction was isolated from the antiserum raised against a 21-kilodalton (kDa) basic protein which was purified from bovine brain cytosol. This fraction was employed to study the immunocytochemical localization of the 21-kDa protein during the development of rat brain. Immunostaining was observed on oligodendrocytes and their processes at all stages of development investigated. This immunostaining was less prominent in very young and adult brains. Myelin fibers were always moderately stained; neurons and astrocytes were not immunolabelled. The electron microscopic study revealed that the labelling covers the entire cytoplasm of the oligodendrocytes, being more dense along the membranes of the rough endoplasmic reticulum and the plasma membrane. Other cytoplasmic organelles were unstained. The present report emphasizes that 21-kDa protein may serve as a specific marker for oligodendroglial cells in the central nervous system despite its presence in peripheral organs.

Animals↗
PubMed1988

Monoclonal antibodies for progesterone receptor assays and polymorphism studies in breast cancer. Comparison with radioligand assays.

Progesterone receptors (PR) from human breast tumors were assayed by a new method using monoclonal antibodies immobilized on beads (PR-EIA, Abbott Laboratories). EIA results were compared to those obtained with the dextran-coated charcoal method using a tritiated ligand (ORG 2058). The precision and reproducibility of the EIA method were studied over a 3-month period: intra-assay coefficients of variation were less than 6% for the range of the assay (between 5-250 fmol/ml), and inter-assay coefficients of variation calculated on 13 consecutive standard curves were less than 10%, except for standard 0 (33%). PR assays performed on 78 tumors both by EIA and radioligand (RLA) were compared. The linear regression obtained was: PR-EIA = 0.81 RLA+1 fmol/mg protein (r = 0.88). For reproducibility studies, cytosols were assayed twice during a period ranging from 1 week-3 months, both by EIA and RLA. The linear regression obtained between the second assay (B) and the first assay (A) was: B = 0.98 A + 11 fmol/mg protein for RLA (r = 0.98), and B = 0.99 A-7 fmol/mg protein for EIA (r = 0.98). To study the effect of KCl on PR-EIA, 26 tumors were homogenized in 0.4 M KCl Tris buffer and assayed both by EIA and RLA. A good correlation was obtained between the 2 methods, but higher values were obtained with PR-EIA (P = 1.6) in comparison with RLA. The addition of KCl to the cytosol showed that KCl had no effect on EIA results, but significantly lowered RLA results. To study the effect of KCl on progesterone receptor isoforms, cytosols were analyzed by chromatography on TSK G3000 SW columns, and the presence of PR was detected in each fraction by both EIA and RLA. In the absence of KCl, only the oligomeric form of PR was observed; however with both techniques, detection of this form different from tumor to tumor, emphasizing the inter-tumoral molecular heterogeneity of PR. After PR isoform dissociation by KCl (0.4 M) and chromatographic analysis of the forms obtained, monoclonal antibodies detected PR molecular forms different from those observed by radioligand; furthermore, chromatographic patterns obtained were different from one tumor to another and confirmed the inter-tumoral molecular heterogeneity of the progesterone receptor.

Antibodies, Monoclonal↗
PubMed1987

Identification of two cell surface proteins of rat brain oligodendrocytes in culture.

Antibodies specific for the surface of oligodendrocytes were prepared by incubating living cultures of pure oligodendrocytes with a crude anti-oligodendrocyte antiserum. These specific antibodies, when used in the technique of immunoelectroblotting, led to the characterization of at least two major plasma membrane proteins of 43 kilodaltons (kDa) and 53 kDa, respectively, as accessible at the external surface of the oligodendrocytes. The 53-kDa protein was also found in oligodendrocyte-conditioned medium in significant amounts. Additional oligodendrocyte surface proteins were also detected in the Wolfgram protein fraction.

Animals↗
PubMed1987

Arrest of proteolipid transport through the Golgi apparatus in Jimpy brain.

Immunocytochemical investigations were performed on Jimpy and control mouse brains using three specific anti-myelin proteolipids antisera: immunoaffinity purified multivalent anti-(PLP + DM-20) proteolipid antibodies, anti-C-terminal hexapeptide 271-276 and anti-tridecapeptide 117-129 antisera. The results show that oligodendrocytes and myelin sheaths in normal mouse brain are labelled to the same extent by the three specific antisera; in contrast, in Jimpy brain these cellular structures are only stained by the multivalent antibodies and the site-specific, anti-tridecapeptide antiserum. The absence of labelling with C-terminal hexapeptide antiserum in mutant brain is interpreted as the result of either a large deletion or a point mutation producing a frameshift in the C-terminal part of the sequences of the proteolipids PLP and DM-20. Furthermore, we show that this mutation prevents the normal transport of proteolipid molecules through the Golgi apparatus. The existence of a minor, extra-Golgi apparatus metabolic route for proteolipids to myelin structures is also discussed.

Animals↗
PubMed1987

Immunocytochemical localization of UDP-galactose: ceramide galactosyltransferase in myelin and oligodendroglial cells of rat brain.

Specific antibodies were prepared against rat-brain UDP-galactose:ceramide galactosyltransferase (CGalT) and used to study the localization of this enzyme at light and electron microscopic levels. Using an immunocytochemical technique the presence of CGalT was revealed in the cytoplasm and processes of oligodendrocytes and in myelin sheaths of developing and adult rat brain. No immunostaining was detected in neurons or astrocytes. At the ultrastructural level the immunostaining of oligodendrocytes was most intense at the periphery of cytoplasm and probably included plasma membrane. Among the intracellular organelles of oligodendrocytes, specific labelling was occasionally seen in the stacks of Golgi apparatus membranes. In myelin sheaths anti-CGalT staining seems to be restricted to the outermost and innermost lamellae. The finding of CGalT in distant portions of oligodendrocyte processes and in loosely wrapped myelin membranes might indicate that myelin galactocerebrosides are synthesized in the proximity of the site of their incorporation into the newly formed myelin.

Animals↗