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Biomedical subjects

D André

Publications and source records attributed to D André.

At least 19 recordsLinked to original sources
PubMed1998

Substance P post-synaptically potentiates glutamate-induced currents in dorsal vagal neurons.

We examined the post-synaptic actions of glutamate, N-methyl-D-aspartate (NMDA) and substance P on dorsal vagal neurons, using the patch-clamp technique on brainstem slices of young rats. The vagal neurons were identified electrically and histologically. All vagal neurons responded to glutamate and NDMA and about 30% to substance P, with dose-dependent inward currents. The glutamate-induced currents were blocked partially by either CPP (3((R)-2-carboxypiperazin-4-yl)-propyl-1-phosphonic acid) or CNQX (6-cyano-7-nitro-quinoxaline-2,3-dione), indicating that these currents resulted from the activation of at least two types of glutamate receptors: NMDA receptors and AMPA/kainate receptors. The NK1 receptor-selective antagonist, RP67580, blocked substance P-induced currents, suggesting that NK1 receptors do coexist with NMDA receptors and AMPA/Kainate receptors. Substance P potentiated the effects of glutamate. This potentiation lasted 10-20 min and was blocked by CPP and by RP67580, but not by CNQX, demonstrating that the increase in glutamate-induced currents resulted from the interaction between NK1 receptors and NMDA channels. These results provided the first evidence that the receptors for substance P and glutamate coexist on dorsal vagal neurons and interact with each other to modulate visceral efferent functions.

Animals↗
PubMed1998

Protective role of gamma interferon in experimental pulmonary paracoccidioidomycosis.

We have developed a murine model of pulmonary infection by Paracoccidioides brasiliensis in which resistance was associated with immunological activities governed by gamma interferon (IFN-gamma). To better characterize this model, we measured type 1 and type 2 cytokines in the lungs and investigated the effect of endogenous IFN-gamma depletion by monoclonal antibodies in the course of infection of susceptible (B10.A) and resistant (A/Sn) mice. At weeks 4 and 8 after infection, lungs from susceptible animals presented levels of IFN-gamma, interleukin-4 (IL-4), IL-5, and IL-10 higher than those in resistant mice. In both mouse strains, neutralization of endogenous IFN-gamma induced exacerbation of the pulmonary infection, earlier fungal dissemination to the liver and spleen, impairment of the specific cellular immune response resulting in significantly lower delayed-type hypersensitivity reactions, and increased levels of immunoglobulin G1 (IgG1)- and IgG2b-specific antibodies. Histopathological analysis demonstrated that depletion of IFN-gamma changes the focal granulomatous lesions found in the lungs of B10.A and A/Sn mice into coalescent granulomata which destroy the pulmonary architecture. These results suggest that irrespective of the mouse strain, IFN-gamma plays a protective role and that this cytokine is one major mediator of resistance against P. brasiliensis infection in mice.

Animals↗
PubMed1997

Determination of pyrazinamide and its main metabolites in rat urine by high-performance liquid chromatography.

A new high-performance liquid chromatograhic procedure for simultaneous determination of pyrazinamide (PZA) and its three metabolites 5-hydroxypyrazinamide (5-OH-PZA), pyrazinoic acid (PA), and 5-hydroxypyrazinoic acid (5-OH-PA), in rat urine was developed. 5-OH-PZA and 5-OH-PA standards were obtained by enzymatic synthesis (xanthine oxidase) and checked by HPLC and GC-MS. Chromatographic separation was achieved in 0.01 M KH2PO4 (pH 5.2), circulating at 0.9 ml/min, on a C18 silica column, at 22 degrees C. The limits of detection were 300 microg/l for PZA, 125 microg/l for PA, 90 microg/l for 5-OH-PZA and 70 microg/l for 5-OH-PA. Good linearity (r2>0.99) was observed within the calibration ranges studied: 0.375-7.50 mg/l for PZA, 0.416-3.33 mg/l for PA, 0.830-6.64 mg/l for 5-OH-PZA and 2.83-22.6 mg/l for 5-OHPA. Accuracy was always lower than +/- 10.8%. Precision was in the range 0.33-5.7%. The method will constitute a useful tool for studies on the influence of drug interactions in tuberculosis treatment.

Animals↗
PubMed1997

[Common fibular nerve lesions. Etiology and treatment. Apropos of 146 cases with surgical treatment].

PURPOSE OF THE STUDY: Common peroneal nerve lesion on the lateral aspect of the knee is one of the most frequent neurologic injury of the lower limb. We reported the results of surgical procedure for each etiological group. MATERIAL AND METHODS: In the peroneal nerve entrapment group, we individualised 62 fibular tunnel syndroms (55 idiopathic, 4 postural, 3 dynamic), and 16 external compression. Traumatic causes were represented by 22 varus injuries of the knee and by 11 fractures, 16 iatrogenic lesions, 2 wounds, 5 wound sequelae, 2 contusions and 1 burn. Tumoral group was represented by 7 intraneural ganglionic cyst and 2 extraneural tumour (1 exostosis and 1 chondromatosis of the proximal tibio fibular joint). All patients underwent surgical procedure. Neurolysis was performed when the nerve was in continuity. Suture or nerve grafting was performed in the other cases. In the case of intraneural ganglionic cyst, a complete tumoral excision was realised. RESULTS: Eighty-three per cent of excellent and good results were obtained for the fibular tunnel syndrom, 62.5 per cent for external compression, 36 per cent for varus injury of the knee, 78 per cent for the other traumatic causes and 89 per cent for tumoral lesions. DISCUSSION: This report confirms that the result depends on the etiology of the common peroneal nerve lesion. We propose surgical treatment within 2 to 4 months for the patients without clinical and electrophysiological improvement. If there is doubt on the continuity of the nerve, we propose an earlier surgical treatment. Our results were in general satisfactory except when a nerve graft was necessary furthermore if it was a traction injury and if the length of the graft was longer than 6 centimeters.

Adolescent↗
PubMed1996

Phenobarbital metabolism by hepatocytes isolated from rat.

In order to test the validity of the use of hepatocytes as an alternative to studies of metabolism in live animals, phenobarbital (PB) was applied at 37 degrees C to isolated rat hepatocytes, which had been previously induced by PB. The metabolites were extracted by ethyl acetate, at various pH, and identified and evaluated by GC-MS. PB was not metabolized to p-hydroxyphenobarbital as is usually the case in living animals, but it was transformed into sulphoconjugated 2-phenyl-gamma-butyrolactone. This pathway, beta-hydroxylation of the ethyl side chain followed by lactonization, previously described as a secondary metabolic pathway occurring during intoxications, was here the only observed biodegradation. These results show that it is not possible to use hepatocytes as an alternative to live animals.

Animal Testing Alternatives↗
PubMed1995

Cloning and sequence analysis of a signal peptidase I from the thermophilic cyanobacterium Phormidium laminosum.

Type I signal peptidases are a widespread family of enzymes which remove the presequences from proteins translocated across cell membranes, including thylakoid and cytoplasmic membranes of cyanobacteria and thylakoid membranes of chloroplasts. We have cloned and sequenced a signal peptidase gene from the thermophilic cyanobacterium Phormidium laminosum which is believed to encode an enzyme common to both membrane systems. The deduced amino acid sequence is 203 residues long and although the overall similarity among signal peptidases is rather low there are a number of identifiable conserved regions present. The P. laminosum enzyme is predicted to have a single transmembrane domain, in contrast to other Gram-negative bacterial sequences, but similar to other type I signal peptidases.

Amino Acid Sequence↗
PubMed1994

GC-MS determination of phenobarbitone entrapped in poly-epsilon-caprolactone nanocapsules.

In order to evaluate the concentration of a hydrophilic drug, phenobarbitone, in a suspension of poly-epsilon-caprolactone nanocapsules, a gas chromatographic-mass spectrometric procedure, performed after methylation of the drug, was developed and validated. Free phenobarbitone (in solution in the liquid phase), released phenobarbitone (after opening the nanocapsules with ethyl acetate) and total entrapped phenobarbitone (after extraction with methylene chloride), were measured. Experimental results for four lots with various concentrations showed that the highest preparation of entrapped drug (80%) was obtained for a total concentration of 3.64 mg ml-1 in the nanocapsule suspension.

Drug Compounding↗
PubMed1993

Plasma fluphenazine levels measured by high-performance liquid chromatography in patients treated with depot injections.

Fluphenazine (CAS 69-23-8) concentrations in plasma of schizophrenic patients after oral (fluphenazine hydrochloride, Moditen) or intramuscular (fluphenazine enanthate, Moditen Retard, or fluphenazine decanoate, Modecate) administration of drug were measured by means of high-performance liquid chromatography. The extracted compound was identified by gas chromatography with mass selective detector. Pharmacokinetics of fluphenazine has been studied.

Blood Specimen Collection↗
PubMed1992

Gas chromatographic-mass spectrometric method for analysis of a pyrimido-s-triazine and some of its metabolites in dog urine.

3-Phenylpyrimido-[3,4-a]-s-triazines exhibit antiparasitic, antibacterial and antifungal activity. In order to study the metabolism of these heterocycles, 9,9-diethyl-3-phenyl-6,8-dioxo-2,3,4,5,6,7,8,9-octahydropyrimido[3 ,4-a]-s- triazine (TZ) was administered to dogs. Three potential metabolites were synthesized, and these models were identified and quantified with gas chromatography-mass spectrometry. The heterobicyclic compounds, TZ and its hydroxy derivative, underwent thermal degradation under chromatographic conditions. Dog urine spiked with the model metabolites was extracted, and the substances were quantified. The urine of dogs treated with TZ was studied, and two of the potential metabolites were recovered, identified and quantified.

Animals↗
PubMed1992

Freezing cocultured human blastocysts.

OBJECTIVE: To determine the possibility of obtaining good pregnancy rates (PRs) after freezing and thawing cocultured blastocysts. DESIGN: Human blastocysts were frozen first according to a protocol available from literature. Two other protocols including the addition of glycerol were designed to improve the results. SETTING: All the patients were under clinical management at the Institut Rhonalpin pour l'Etude de la Reproduction Humaine in Lyons, France. PATIENTS: Patients involved in the in vitro fertilization program have had their supernumerary embryos frozen according to the three protocols presented here. MAIN OUTCOME MEASURES: Embryo recovery after freezing and thawing. Clinical and ongoing pregnancies after embryo transfer (ET). RESULTS: A protocol including sucrose addition and reduction of steps in the preparation of the blastocysts for freezing gave us a 21% PR per transfer (15 ongoing) of 101 transfers (106 thawings). CONCLUSIONS: Freezing of cocultured human blastocysts allow good PRs. This can represent an alternative for repeated failures of ETs at early stages.

Blastocyst↗
PubMed1992

[Early diagnosis of pregnancy in the cow as assessed by milk ejection induced by luteal oxytocin].

The diagnosis of pregnancy described in this article is based on the observation of milk ejection which, in the case of corpus luteum maintenance, results from the release of luteal oxytocin induced by intravenous administration of a non luteolytic dose of PGF2 alpha. The tests were performed in 410 lactating cows, 18-22 days after insemination (mean 19.95 days, SD 0.75), 3 h prior to the evening milking. A cannula was placed in the left fore-teat; when the cisternal milk flow ceased, a small dose of a prostaglandin F2 alpha analogue (256 micrograms Dinolytic) was injected. If a corpus luteum was present, the alveolar milk flow (1,276 +/- 570 ml) started 86 +/- 35 s later and pregnancy could be presumed. If the corpus luteum was no longer functional, the milk flow did not start again and the cow was considered not pregnant. The accuracy of positive results, ie 72.3%, significantly exceeded that obtained by radioimmunoassay of plasma progesterone used as a reference method, ie 68.6% (P less than 0.05). By contrast, the accuracy of negative results was lower, ie 93.5 vs 100%, (P less than 0.05): of the 195 pregnant cows which proceeded to term, 10 did not respond to the milk ejection test. In spite of these reserves, the test has the advantage of being inexpensive, rapid (about 5 min) and easy to interpret, ie either the milk flows or it does not. In addition, it may be used early, because from day 20 after Al the reliability of prediction of non pregnant cows (67.0%) was significantly higher when compared to the use of progesterone radioimmunoassay (58.6%) (P less than 0.05). With such a test, non pregnant cows can be reinseminated immediately and not only after a 3-week period. This may contribute to reducing the length of the infertile period.

Animals↗
PubMed1992

[Treatment and secondary prophylaxis with fluconazole for oropharyngeal candidiasis in HIV-positive patients. A mycological analysis of failures].

This prospective study evaluated the in vitro susceptibility of Candida albicans isolates recovered from the oral cavity of AIDS/ARC patients before and during long-term therapy with fluconazole. Thirty adults (15 with ARC and 15 with AIDS) with a first episode of thrush candidiasis were given oral fluconazole (Triflucan 50 mg; one capsule daily) for at least three months. Fungal susceptibility testing was performed before treatment, after one month, and at last follow-up (range 3.5-12 months; mean 5.7 months). MICs were determined using the agar dilution method with casitone (Difco 259-01) as the test medium at pH 7.2-7.4. There were two initial clinical failures (one with high MICs before and under treatment and one with an intermediate MIC initially and a rise in MIC under fluconazole). Four patients developed a clinical relapse with no change in MICs (which were low or intermediate). In six patients, clinical symptoms resolved but carriage of C. albicans persisted (low MICs). In 18 patients, clinical resolution with eradication of C. albicans was achieved. These data suggest that (1) clinical failures may be associated with in vitro resistance; (2) relapses under fluconazole maintenance therapy may develop in patients with advanced HIV disease despite the lack of change in the susceptibility of strains.

Acquired Immunodeficiency Syndrome↗
PubMed1987

GABA nerve endings in the rat red nucleus combined detection with serotonin terminals using dual immunocytochemistry.

Immunocytochemical methods were used to examine the ultrastructural features and cellular interrelationships of GABA and serotonin afferent fibers to the rat red nucleus. GABAergic nerve endings were identified in two ways, either using a pre-embedding immunoperoxidase procedure with an antibody against glutamate decarboxylase, the GABA-synthesizing enzyme, or after post-embedding immunogold labelling with an anti-GABA antibody. With the latter approach, it was possible to simultaneously visualize the GABAergic and serotoninergic innervation of the red nucleus (magnocellular part) in electron microscope preparations. This procedure involved GABA labelling of ultrathin sections obtained from specimens previously immunostained for serotonin using the pre-embedding peroxidase-antiperoxidase technique. The doubly stained sections showed gold and peroxidase markers to be present in two distinct populations of axonal varicosities. Unlike the GABAergic nerve endings, which were found to be profusely distributed throughout the nucleus, the serotonin nerve endings were relatively scarce. They contacted dendrites of large-sized neurons usually endowed with several GABA-gold labelled terminals. Not uncommonly, direct appositions between serotonin and GABA-positive terminals were also encountered. These data provide morphological evidence that red nucleus outputs may be dually regulated by GABAergic and serotoninergic afferents, while suggesting that presynaptic GABA/serotonin interactions might also play a significant part in red nucleus functions.

Animals↗
PubMed1985

Treatment of vaginitis with benzydamine: preliminary results of a randomized study.

The therapeutic efficacy of benzydamine vaginal douche is compared with that of placebo in a randomized clinical study presently underway. A total number of 200 patients, grouped according to different types of vaginitis, will be included in the study. Preliminary results on 102 patients confirm the positive therapeutic effect of benzydamine.

Benzydamine↗
PubMed1985

[Diagnosis and treatment of fetal tachycardia. Apropos of 2 cases].

Fetal echocardiographic studies were performed in 2 patients referred for evaluation of cardiac dysrythmias. Supra-ventricular tachycardia were diagnosed in the 2 patients. Appropriate prenatal treatment can not avoid premature deliveries in one case. Evaluation of in utero cardiac arrhythmias and monitoring of in utero therapy are discussed.

Digoxin↗
PubMed1983

The opine synthase genes carried by Ti plasmids contain all signals necessary for expression in plants.

Signals necessary for in vivo expression of Ti plasmid T-DNA-encoded octopine and nopaline synthase genes were studied in crown gall tumors by constructing mutated genes carrying various lengths of sequences upstream of the 5' initiation site of their mRNAs. Deletions upstream of position -294 did not interfere with expression of the octopine synthase gene while those extending upstream of position -170 greatly reduced the gene expression. The estimated size of the octopine synthase promoter is therefore 295 bp. The maximal length of 5' upstream sequences involved in the in vivo expression of the nopaline synthase gene is 261 bp. Our results also demonstrated that Ti plasmid-derived sequences contain all signals essential for expression of opine synthase genes in plants. Expression of these genes, therefore, is independent of the direct vicinity of the plant DNA sequences and is not activated by formation of plant DNA and T-DNA border junction.

Journal Article↗
PubMed1981

[Auto-immunity and ovarian failure (author's transl)].

The authors report the case of a 17 year-old girl presenting with primary amenorrhea. Investigations showed that it was due to auto-immune hypogonadism. Such an etiology is rarely found in ovarian insufficiencies. In the reported case, there was no other associated auto-immune disorder. Two types of anti-ovarian antibodies are known: antibodies to steroid-producing cells and antibodies to germ-cells. The first ones are found in patients presenting with auto-immune Addison's disease, and are directed against antigens common to ovary and adrenal glands and their presence does not imply ovarian dysfunction. The second ones are more specific and found chiefly in patients with sterility and amenorrhea; they are divided into 2 subgroups: antibodies against the cytoplasm of the ovacyte antibodies and antibodies against zona pellucida. In patients with primary ovarian insufficiency, the presence of such antibodies should always be investigated.

Adolescent↗