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C Olivier

Publications and source records attributed to C Olivier.

At least 37 records · Page 2Linked to original sources
PubMed2000

Synthesis and biological evaluation of bradykinin B(1)/B(2) and selective B(1) receptor antagonists.

We recently described a potent bradykinin B(2) receptor agonist (JMV1116) obtained by replacing the D-Tic-Oic dipeptide moiety of HOE140 by a (3S)-amino-5-(carbonylmethyl)-2,3-dihydro-1, 5-benzothiazepin-4(5H)-one (D-BT) moiety. This compound inhibited the specific binding of [(3)H]BK on membranes of CHO cells expressing the human cloned B(2) receptor with nanomolar affinity and contracted both isolated rat uterus and human umbilical vein. These data demonstrated that D-BT could be a good mimic of the Pro-Phe dipeptide. In the present study we characterized B(1) receptor antagonists containing the D-BT moiety. We prepared an analogue of compound JMV1116 deleting the C-terminal arginine residue. The resulting compound (1) had an affinity of 83 nM for the human cloned B(1) receptor. The most remarkable property of 1 is its ability to bind also the B(2) receptor with an affinity of 4.4 nM despite the absence of the C-terminal arginine residue. Modifications at the N-terminal part of 1 associated with the substitution of the thienylalanine residue by alpha-(2-indanyl)glycine resulted in analogues selectively binding to the B(1) receptor with an affinity in the picomolar range.

Animals↗
PubMed2000

Identification of a gp130 cytokine receptor critical site involved in oncostatin M response.

Gp130 cytokine receptor is involved in the formation of multimeric functional receptors for interleukin-6 (IL-6), IL-11, leukemia inhibitory factor (LIF), oncostatin M (OSM), ciliary neurotrophic factor, and cardiotrophin-1. Cloning of the epitope recognized by an OSM-neutralizing anti-gp130 monoclonal antibody identified a portion of gp130 receptor localized in the EF loop of the cytokine binding domain. Site-directed mutagenesis of the corresponding region was carried out by alanine substitution of residues 186-198. To generate type 1 or type 2 OSM receptors, gp130 mutants were expressed together with either LIF receptor beta or OSM receptor beta. When positions Val-189/Tyr-190 and Phe-191/Val-192 were alanine-substituted, Scatchard analyses indicated a complete abrogation of OSM binding to both type receptors. Interestingly, binding of LIF to type 1 receptor was not affected, corroborating the notion that in this case gp130 mostly behaves as a converter protein rather than a binding receptor. The present study demonstrates that positions 189-192 of gp130 cytokine binding domain are essential for OSM binding to both gp130/LIF receptor beta and gp130/OSM receptor beta heterocomplexes.

Alanine↗
PubMed2000

Spatiotemporal development of oligodendrocytes in the embryonic brain.

In the central nervous system (CNS), oligodendrocytes have long been considered to be the last cell type to be generated during development. In rodents, the progenitor cells that give rise to oligodendrocytes have been reported to originate in the subventricular zone. Here, we review recent data demonstrating the existence of oligodendrocyte precursor cells in the ventricular layer of the neural tube that emerge prior to the progenitor stage. Oligodendrocyte precursors arise in restricted foci that are distributed along the rostrocaudal axis of the neural tube, for the most part ventrally. The generation of oligodendrocyte precursor cells occurs either simultaneously with, or follows closely upon the emergence of the first neurons. Experiments with quail-chick chimeras provide evidence that oligodendrocyte progenitors derived from ventricular precursors migrate either tangentially or radially to colonize extensive or segmentally restricted territories of the brain. The choice depends on their site of origin. Finally, we discuss the possibility that oligodendrocytes could be a mosaic population that originates from at least two types of precursor cells.

Animals↗
PubMed2000

Single or multiple oligodendroglial lineages: a controversy.

The text books all say oligodendrocytes are the last cell to arise during development. The analysis of the spatio-temporal pattern of expression of plp/dm-20 during embryonic development in both the chick and the mouse provides evidence that the induction of oligodendrocyte occurs much earlier than we thought. In fact, it seems as though these cells must arise nearly simultaneously with neurons and it is just that they do not mature until later. Furthermore, we review the experimental arguments in favor of the existence of at least two, if not more, oligodendrocyte precursor cells: one is defined by the expression of PDGFRalpha, another characterized by expression of plp/dm-20 is independent from PDGF-AA for its proliferation and survival. We then postulate the existence of a third family of yet unknown origin.

Animals↗
PubMed2000

[Intradermal tuberculin test].

Mantoux test expresses a delayed hypersensitivity induced after either BCG vaccination or a BK contact. In France, a purified protein fraction is used. The quality of technique and lecture are essential. The lowest positivity limit is > 5 mm. Sensitivity and specificity are imperfect. For the interpretation of positivity, the most important factors are the age of vaccination (the younger the child is, the lower the reaction is) and the infection prevalence rate in the group considered (the lowest it is, the highest a criteria may be used for induration > 15 mm). The background is most important for interpretation. The main situations are a postvaccinal test, a diagnosis of infection (or illness) or the environment of a contagious adult. A lot of situations are less clear and require the knowing of a risk factor (risk people, contagion...). In spite of these limits, Mantoux test is the only valid technique, useful when considered with other points: collective (prevalence of the illness in some groups) or individual (contagion, clinical or radiological signs...).

Adult↗
PubMed2000

Rheumatic fever--is it still a problem?

The incidence of rheumatic fever has declined in industrialized countries since the 1950s and now has an annual incidence of around 0.5 cases per 100,000 children of school age. In developing countries it remains an endemic disease with annual incidences ranging from 100 to 200 per 100,000 school-aged children and is a major cause of cardiovascular mortality. Interest in the pathogenesis of rheumatic fever was rekindled by outbreaks in the USA (1985-1987) and the rare cases still seen in industrialized countries. The current concept is that the disease results from the host's poorly adapted autoimmune response to group A beta-haemolytic streptococci. The risk of developing rheumatic fever following untreated tonsillopharyngitis is 1% in the civilian population. Knowledge of virulence factors has been greatly enriched by progress in molecular biology. One of the key elements is protein M, a surface protein on the bacterial wall which carries specific epitopes. Several serotypes which lead to rheumatic fever have been recognized among more than 80 identified serotypes. However, the reason why specific strains within a given serotype have increased rheumatogenic virulence remains unknown. The causal strain adheres to the oral and pharyngeal cells and then releases its degradation products. These products present antigenic determinants which cross-react with certain human tissues, particularly in cardiac valve tissue and myocardium. Diagnosis is now difficult owing to the low incidence. Late diagnosis can have serious consequences and acute rheumatic fever is a therapeutic emergency requiring immediate antibiotic and anti-inflammatory treatment. In most of Europe there is tacit agreement that all cases of pharyngitis and tonsillitis should be treated with antibiotics without identification of the causal agent despite the fact that only about 20% of the cases are caused by group A beta-haemolytic streptococci, and could lead to rheumatic fever.

Developed Countries↗
PubMed1999

Early specification of oligodendrocytes in the chick embryonic brain.

Oligodendrocytes are the myelin-forming cells in the central nervous system of vertebrates. In the rodent embryo, these cells have been shown to emerge from restricted territories of the neuroepithelium. However, a comprehensive view of the development of oligodendroglial populations from their ventricular sources remains to be established. As a first step toward this aim, we have examined in vivo the spatiotemporal emergence of oligodendrocytes in the chick embryonic brain. We have detailed the patterns of expression of three early markers of the oligodendroglial lineage: the plp/dm-20 and PDGFRalpha transcripts and the O4-reactive antigen. During embryonic development, these molecules showed a similar segmental pattern of expression. However, plp/dm-20(+) cells were already observed, in the ventricular layer, at E2.5, i.e., 2 days before the appearance of O4(+) and PDGFRalpha(+) cells, suggesting that oligodendrocyte precursors arise nearly simultaneously with neurons. In the chick embryonic brain, the onset of expression of plp/dm-20 appears therefore to be the earliest event indicative of oligodendroglial specification and we propose, based on the expression of plp/dm-20 transcript, a ventricular map of the foci at which oligodendrocytes originate. In addition, we document the precocious segregation, from E5, of plp/dm-20(+) and PDGFRalpha(+) oligodendroglial cells in the subventricular and mantle layers of the brain.

Animals↗
PubMed1999

[Severe lactic acidosis disease disclosing milk-protein intolerance to cows' milk].

UNLABELLED: The age of discovery and initial symptoms of cow milk allergy can vary. Lactic acidosis is exceptionally associated to this allergy. CASE REPORT: A 32-day-old girl was admitted for a severe malaise with metabolic acidosis and hyperlactacidemia. There were no neonatal or family problems; breastfeeding was stopped on the 25th day. Fever was noted on the 29th day and her mother reported behavior anomalies followed by a severe malaise with unconsciousness between the 29th and 32nd day. At admission, the infant showed a severe neurological distress, hypotonia and lethargy. Infection and neurological imaging were normal. A compensated metabolic acidosis with hyperlactacidemia (5.96 mmol/L) was noted. There was no argument for esophageal reflux nor vagal hypertony; mitochondrial cytopathy was also excluded. After a 24 hours fast, the clinical state gradually improved and normalized at h48. The infant was discharged with a milk protein hydrolysate formula. Her mother attempted to reintroduce cow milk on the 59th and 64th day, but this was immediately followed by allergic manifestations which supported the diagnosis of cow milk allergy. CONCLUSION: Neurological distress and hyperlactacidemia exceptionally reveal this type of intolerance. The mechanism of hyperlactacidemia remains unclear; it is possibly the consequence of severe changes of the intestinal mucosa, an exclusive glycolytic tissue.

Acidosis, Lactic↗
PubMed1999

[Long QTc interval complicating halofantrine therapy in 2 children with Plasmodium falciparum malaria].

UNLABELLED: Halofantrine has been shown to be very effective against multiple drug resistant falciparum malaria. It is usually administered in children at 24 mg/kg at six-hour intervals for three doses, and a second therapeutic course one week following the initial treatment is recommended. It is usually well tolerated. However, prolongation of the QT interval has been reported in adults receiving this drug for malaria. CASES REPORTS: Two children experienced a prolongation of the QTc interval while receiving halofantrine. The first child, aged two years, had a prolonged QTc interval (490 ms) six hours after the third administration, at the usual therapeutic dose. The second child, aged six years, had a normal QT interval (360 ms) after the first 24 mg/kg dose and had a prolonged QTc (450 ms) during the second course seven days later, 15 h after the last dose. In both cases, the QTc interval returned to normal values (below 440 ms) rapidly after the end of treatment. CONCLUSION: Cardiotoxic effects are felt to be dose-dependant and young children may be particularly at risk due to pharmacological and cardiac immaturity. Therefore, guidelines for drug administration should be followed (administration in a child with an empty stomach, drug not recommended in combination with drugs known to prolong the QTc interval) and monitoring ECG in pediatric patients may be justified. The modalities of the second course in children, which is recommended by the manufacturer to travellers from non-endemic areas, should also be discussed.

Adult↗
PubMed1999

The association between CD2+ peripheral blood lymphocyte subsets and the relapse of bladder cancer in prophylactically BCG-treated patients.

We investigated the potential existence of differences in the distribution of T-lymphocyte subsets and in the proliferative response of these CD2+ cells to polyclonal mitogens in patients with transitional cell bladder carcinoma (SBTCC) treated with prophylactic intracavitary instillations of bacillus Calmette-Guerin (BCG) according to their clinical response to this treatment. Before BCG treatment, different subset distribution (CD8+ and CD3+ CD56+), activation antigen expression (CD3+ HLA- DR+) and proliferative response to mitogenic signals were found in CD2+ cells from SBTCC patients prophylactically treated with BCG who remained free of disease or those who had recurrence of tumour. Otherwise, the prophylactic intracavitary BCG instillations in SBTCC patients are associated with a transitory variation of T-lymphocyte subset distribution (CD4 and CD8) and activation antigens expression (CD25).

Adjuvants, Immunologic↗
PubMed1999

Immunological changes in peripheral blood mononuclear cells of patients with metastatic renal cell carcinoma after low doses of subcutaneous immunotherapy with IFN-alpha-2b and IL-2.

To elucidate the immunologic changes induced by low doses of subcutaneous interferon (IFN)-alpha-2b plus interleukin-2 (IL-2) in patients with metastatic renal cell cancer, we have studied a group of eight patients undergoing two cycles of immunotherapy after radical nephrectomy. Natural killer (NK) cytotoxic activity, proliferative response to T-lymphocyte mitogens, and phenotypic profile of T and NK cells were determined in peripheral blood mononuclear cells (PBMCs) before and after each cycle. No significant differences were found in either of the studies realized between untreated patients and their counterpart healthy controls. However, after the first cycle, there was a significant increase in NK-cytotoxic activity and in the number of CD16+/CD56+ cells that parallelled a significant decrease in the percentage of CD3+ and CD4+ lymphocytes with no changes in the proliferative response to T-cell mitogenic signals. Individual analysis of each patient on the basis of their clinical response to treatment showed that after the first cycle of immunotherapy there were no significant differences in the immunological profiles analyzed between patients with complete or partial responses and those who did not respond to treatment, whereas, at the end of the second cycle, patients who achieved complete or partial clinical responses had higher NK-cytotoxic activity that those who remained in disease progression. We conclude that subcutaneous immunotherapy with IFN-alpha-2b and IL-2 induces a systemic immunomodulatory effect on PBMCs, manifested preferentially in a systemic NK activation and expansion that is related to the clinical outcome.

Aged↗
PubMed1998

Multiple restricted origin of oligodendrocytes.

The plp gene encodes the proteolipid protein and its alternatively spliced product DM-20, major proteins of CNS myelin. In the mouse, plp/dm-20 transcripts are expressed beginning at embryonic day 9.5 (E9.5) by restricted foci of germinative neuroepithelial cells. To determine the identity of the neural precursors expressing plp/dm- 20, a zeomycin resistance gene fused to the lacZ reporter was expressed in transgenic mice under the control of the plp regulatory sequences. In the three different lines generated, the pattern of beta-galactosidase expression was similar and superimposable on the expression pattern of endogenous plp/dm-20. Both in vivo and in vitro, the transgene was expressed by O4(+) pre-oligodendrocytes, and later by RIP+ differentiated oligodendrocytes, but not by neuronal cells, astrocytes, or radial glial cells. After zeomycin selection, a dramatic enrichment in O4(+) pre-oligodendrocytes was observed in cultures derived from E12.5 transgenic embryos. This enrichment indicates the oligodendroglial specification of neural precursors that continuously express plp/dm-20. Early plp/dm-20-expressing precursors, however, appear to be a separate population from previously described PDGFRalpha oligodendrocyte precursors, as shown by the striking differences in their (1) patterns of distribution and (2) responsiveness to PDGF. These data suggest that oligodendrocytes have a plural origin and that early plp/dm-20 defines one of the neural lineages generating oligodendrocytes.

Animals↗
PubMed1998

-Skin eruption after the first dose of antitubercular quadri-therapy: consideration of pyrazinamide-.

UNLABELLED: We report a rash after the first dose of antituberculosis polytherapy which raises questions concerning procedures to be followed. CASE REPORT: An 8-year-old child presented with a pruritic rash 1.5 hours after the first dose of isoniazide, rifampicine, pyrazinamide and ethambutol was simultaneously administered, which did not recur after successive re-administration of isoniazide and rifampicine. Pyrazinamide, which was re-administered last, induced a recurrence. Slower pyrazinamide re-administration allowed continuation of treatment. CONCLUSION: A protocol for re-administration of the four drugs is suggested.

Antibiotics, Antitubercular↗