Biomedical subjects

M Bastide

Publications and source records attributed to M Bastide.

At least 19 recordsLinked to original sources

PubMed1998

Simple and sensitive method for determination of metronidazole in human serum by high-performance liquid chromatography.

A simple and sensitive HPLC method for determination of metronidazole in human plasma has been developed. A step of freezing the protein precipitate allowed an efficient separation of aqueous and organic phases minimizing the noise level and improved therefore the limit of quantitation (10 ng ml(-1) using 1 ml of plasma sample). The separation of compounds was performed on a RP 18 column with acetonitrile-aqueous 0.01 M phosphate solution (15:85, v/v) as mobile phase. Detection was performed by UV absorbance at 318 nm. Metronidazole was well resolved from the plasma constituents and internal standard. An excellent linearity was observed between peak-height ratios plasma concentrations over a concentration range of 0.01 to 10 microg ml(-1). Within-day and between-day precision (expressed by relative standard deviation) and accuracy (mean error in per cent) did not exceed 4% between 1 and 10 microg ml(-1) and 8.3 and 7.2% respectively for the limit of quantitation. The method is suitable for bioavailability and pharmacokinetic studies in humans.

Antitrichomonal Agents↗

PubMed1997

Murine macrophage elastolytic activity induced by Aspergillus fumigatusstrains in vitro: evidence of the expression of two macrophage-induced protease genes.

The interaction between Aspergillus fumigatus conidia and murine macrophages of various origins was investigated. Cocultures were carried out between A. fumigatus strains and freshly isolated murine pulmonary alveolar macrophages or two murine macrophage cell-lines: murine alveolar cell-line MALU and murine astrocytoma cell-line J774. By measuring the variation of elastolytic activity in the coculture supernatants with two elastin substrates, we demonstrated that either viable or fixed A. fumigatus or C. albicans yeasts or nonspecific particles induced significant macrophage elastolytic activity. The effect of A. fumigatus supernatant or the purified A. fumigatus galactomannan suggested also the possible involvement of this polysaccharide in macrophage-protease gene expression, release, and activity in invasive aspergillosis. The effect of inhibitory compounds demonstrated the potential implication of a macrophagic metalloprotease and a macrophagic cysteine protease. RNA analysis allowed us to demonstrate the induction of expression of two macrophagic protease genes in stimulated macrophages. Two distinctive mechanisms appeared to be implicated in macrophage protease induction: nonspecific phagocytosis in the earliest times of the coculture and (or) specific galactomannan recognition after its gradual release by the mycelium.

Animals↗

PubMed1997

A communication process: a new paradigm applied to high-dilution effects on the living body.

Living beings communicate with their world nonverbally, whether on a somatic or a psychological level. This paradigm of signifiers or sense takes place in the framework of the logic of analogy. The signifier is the semantic object that materially designates information to be transmitted and dealt with; a homeopathic remedy is the mimetic representation of the disease. Differential levels of information organize the spread of signifiers; each level is the result of regulation and integration of the previous level. The living self is the never-ending process whereby levels of information are synthesized in the face of the informing environment. Such representations meet one another in the communication between the patient and the physician-remedy system. The medical device must reinform the patient and make the patient's signs and symptoms move toward a higher level of integration. The dilution of the remedy permits us to receive and treat it as information about disease. Signs and symptoms can be recognized as an erroneous adaptation; the organism is engaged in a process of paradoxical negation. The action of the remedies consists of a dynamic analogy between pieces of information. The paradigm of signifiers offers a new possibility for the exploration of informative therapeutics.

Communication↗

PubMed1997

Biological effects of continuous exposure of embryos and young chickens to electromagnetic fields emitted by video display units.

The effects of continuous exposure of embryos and young chickens to electromagnetic fields (EMFs) emitted by video display units (VDUs) were investigated. Embryos and brood were continuously exposed during embryonic and postembryonic phases to EMFs emitted by two types of VDU (TV or computer). Embryonic mortality was evaluated in three independent experiments. Young chickens were immunized three times by porcine thyroglobulin (Tg). Blood samples were assayed after each immunization for specific anti-Tg antibodies (IgG), plasma corticosterone (CORT), and plasma melatonin (MLT). In the sham-exposed samples, embryonic death (10-33%) was restricted to the perinatal period and the IgG, CORT, and MLT responses of young chickens crested after the second immunization. Constant EMF exposure was accompanied by significantly increased fetal loss (47-68%) and markedly depressed levels of circulating anti-Tg IgG, CORT, and MLT. Collectively, these findings indicate that continuous exposure to EMFs, issuing from VDUs, adversely affects embryos and young chickens.

Animals↗

PubMed1996

Effect of calcitonin gene-related peptide and vasoactive intestinal peptide on murine CD4 and CD8 T cell proliferation.

The effects of alpha calcitonin gene-related peptide (alpha CGRP) and vasoactive intestinal peptide (VIP) on the proliferation of CD4 and CD8 T-murine lymphocytes were investigated. When stimulated by a combination of phorbol 12-myristate-13-acetate (PMA) and calcium ionophore (A23187), both neuropeptides in a range of 10(-7)-10(-10) M had an inhibitory effect on the proliferative response of unfractionated splenocytes as well as of purified CD4 and CD8 T lymphocytes. The inhibitory effect of these two neuropeptides was completely or partially blocked by the antagonists of CGRP and VIP receptors. CGRP8-37 and (p-Cl-D-Phe6, Leu17VIP, respectively. The inhibitory effects of each neuropeptide on purified T cells were observed within 4 h after PMA/A23187 activation and their inhibitory actions were correlated with a decrease of IL-2 production. In addition, the two neuropeptides in a range of 10(-7)-10(-10) M induced a rapid and dose-dependent increase in intracellular cAMP in CD4 and CD8 T cells. This suggests the involvement of this second messenger in the inhibitory effects of these two neuropeptides. Taken together these results show that CD4 and CD8 spleen cells represent at least two of the cellular targets for CGRP and VIP inhibition of proliferation mediated by the same type of mechanism.

Animals↗

PubMed1996

A role for bursa fabricii and bursin in the ontogeny of the pineal biosynthetic activity in the chicken.

The tripeptide bursin (Lys-His-Gly-NH2) is a B cell differentiation hormone derived from the bursa fabricii. The latter is a cloacal diverticulum and the site of B lymphocyte differentiation and selection in aves; also the bursa fabricii is involved in endocrine functions. Herein we demonstrate that in the chicken, the bursa fabricii and bursin are crucial to the ontogeny of both the pineal response to antigenic challenge and pineal circadian synthetic activity. In early embryonically bursectomized chickens, the plasma melatonin response to immunization by porcine thyroglobulin (Tg) was abolished. Also, the amplitudes of both plasma melatonin and pineal N-acetyltransferase (NAT) circadian rhythms were reduced by 50%, whereas the activity of hydroxyindole-O-methyltransferase (HIOMT) remained unchanged. Conversely, administration of either minute amounts (100 pg, 100 fg) or highly dilute (5 x 10(-27) g) bursin, with the exception of a highest dose (100 micrograms), to bursaless embryos induced recovery of normal antigen-induced melatonin response and normal amplitudes of melatonin and NAT rhythms. These findings establish that early in embryonic life, the bursa fabricii and its derived signal (bursin) are essential for normal development of pineal synthetic activity and underline the efficacy of very dilute bursin as an informative signal.

Acetylserotonin O-Methyltransferase↗

PubMed1995

Idiotypic restriction of murine monoclonal antibodies to a defined antigenic region of human thyroglobulin.

In previous studies, we demonstrated that anti-human thyroglobulin (hTg) autoantibodies in patients with thyroid disorders exhibit a restricted epitopic specificity towards antigenic region II defined by its reactivity with four murine monoclonal antibodies (mAb 3, 6, 10, 15). To analyze the relationships between epitopic specificity and idiotypic expression of these mAb, two polyclonal anti-idiotypic sera were generated in rabbits by immunization with F(ab')2 fragments of mAb 3 and mAb 10. These anti-idiotypic preparations (AI 3 and AI 10) were tested against a panel of hTg-mAb produced in different strains of mice (HR BIOZZI and BALB/c). The idiotypic analysis showed that AI 3 and AI 10 specifically recognized framework-associated idiotopes as well as paratope-associated idiotopes shared by region II mAb. These results demonstrate that specificity for region II was strongly associated with a restricted idiotype suggesting a high sequence homology between V regions. In addition, naïve BALB/c mice immunized with AI 3 or AI 10 produced anti-hTg (Ab3) antibodies that recognize region II epitopes. These latter findings reveal that anti-Id contain a population of Ab2 beta carrying the internal image of region II epitopes.

Animals↗

PubMed1994

Chemiluminescence and nitrite determinations by the MALU macrophage cell line.

The MALU macrophage cell line is an in vitro coculture of mesothelial cells and alveolar macrophages from mice. During the culture, macrophages in a preactivated state can be collected in the supernatant (Lombard et al., 1988). We describe here two methods to measure reactive oxygen intermediate (ROI) and reactive nitrogen intermediate (RNI) production by the MALU macrophages. We measured ROI by the chemiluminescence assay with a luminometer and RNI was measured colorimetrically in a spectrophotometer with the Griess reagent. Different parameters (cell number, incubation time, temperature and activating substance) which can interfere with the cell response were analysed. Our results show that the MALU macrophage cell line produces large amounts of ROI and RNI after activation. This cell line is a good model for investigating the effect of pharmacological drugs on ROI and RNI production.

Animals↗

PubMed1994

An efficient immunization protocol for production of monoclonal antibodies against soluble human insulin.

A new immunization protocol has been developed to obtain specific monoclonal antibodies (mAb) directed against the soluble form of human insulin. Various protocols differing on the basis of the nature of immunogen, the number of injections and the route of administration of the antigen were compared. Mice with the highest anti-insulin titers were selected for cell fusion. The results showed that the immunization protocol involving 2 injections of insulin followed by a boost 2 months later mainly stimulated B lymphocytes secreting IgM mAb directed against immobilized insulin. Immunization with 2 injections of human proinsulin followed by 2 injections of a human insulin-bovine serum albumin conjugate and finally with a booster injection of this conjugate on each of the last 4 days preceding fusion was necessary to obtain a high percentage of hybridomas secreting specific IgG mAb able to recognize immobilized insulin (indirect ELISA) as well as iodinated insulin (liquid-phase radioimmunoassay).

Animals↗

PubMed1994

Kinetics of appearance of intestinal lesions in mice mono-associated with a lethal or non-lethal strain of Clostridium difficile.

The kinetics of the appearance of intestinal lesions induced by orogastric inoculation of gnotobiotic mice with a lethal strain of Clostridium difficile (VPI) that produced toxins A and B in vivo and in vitro was studied and compared with the lesions induced by non-lethal C. difficile strain 786 that produced toxins A and B in vitro but only toxin B in measurable amounts in vivo. Different portions of the intestine were removed 12, 20, 26 and 30 h after inoculation and studied by scanning electronmicroscopy. The remaining portions were homogenised for enumeration of C. difficile and quantification of toxin A by enzyme immunoassay and toxin B by cytotoxicity. The results showed that, following inoculation: (i) measurable amounts of both toxins were necessary to produce lesions; (ii) with strain VPI, the caecum and the colon were rapidly impaired and completely destroyed after 1 day, whereas the small intestine was damaged to a lesser extent; (iii) C. difficile strain 786 did not cause mucosal damage but induced mucus-like or serum-like secretion and morphological changes in the caecal enterocytes only.

Animals↗

PubMed1994

Dialysis solutions buffered with lactate or bicarbonate: in vitro comparison of two dialysis solutions on human peritoneal cell growth from ESRD and non-ESRD patients.

In order to evaluate the injury to the mesothelial cell layer during long-term peritoneal dialysis (PD), a dialysis solution (solution A), buffered with bicarbonate, stabilized with 10 mmol/L glycylglycine, and sterilized by filtration (0.22 micron double filtration, pH = 7.4), was compared to traditional heat sterilized lactate solution (solution B) on human mesothelial cell cultures. The respective effects of both solutions were evaluated on first passage cells by 3H thymidine incorporation after 72-, 96-, 120-, and 144-h contact. Mesothelial cells to be cultured were obtained from the omentum biopsies of 7 end-stage renal disease (ESRD) patients (during first peritoneal catheter placement) and from 7 non-ESRD patients undergoing abdominal surgery. Solution A (diluted 1/5) induced a time-dependent stimulation of growth in 6 cases of ESRD patient cell cultures, and inhibition occurred only in 1 case. Stimulation was also observed in 5 non-ESRD patient cell cultures, and no effect occurred in 2 cases. Solution B inhibited growth in all the cultures except in 1 case of an ESRD patient in which no effect was observed. This study shows that solution A induced mesothelial cell proliferation, while an inhibitory effect of solution B was observed. No significant differences were observed between the sensitivity of mesothelial cells from ESRD and non-ESRD patients. Further analysis will be carried out to identify precisely the cause of the differences observed: buffer or glycylglycine by themselves and/or glucose by-products.

Aged↗

PubMed1993

Determination of phloroglucinol in human plasma by gas chromatography-mass spectrometry.

A specific and sensitive method has been developed for the determination of phloroglucinol in plasma; it involves an optimized procedure for blood sampling designed to minimize the in vitro oxidation of the molecule, and gas chromatography-mass spectrometry after silylation of the compound. The method allowed a reliable determination of phloroglucinol in plasma. The precision and accuracy of the assay, reported as coefficients of variation, were below 15%. Using a plasma sample of 0.25 ml, the limit of quantitation was 5 ng/ml with a precision of 17.4%, which is sensitive enough for pharmacokinetic studies. Stability studies under different conditions revealed that ascorbic acid limits the degradation of phloroglucinol in plasma during storage at freezer temperatures.

Drug Stability↗

PubMed1993

Factors involved in catheter obstruction during long-term peritoneal insulin infusion.

OBJECTIVE: To analyze the efficacy of ECPII and the factors responsible for technical problems often encountered. This treatment has been in use with IDDM patients since 1980. RESEARCH DESIGN AND METHODS: Forty-four IDDM patients were treated by ECPII for 42-78 mo (mean, 53 mo). RESULTS: Glycemic equilibrium was improved during treatment (mean plasma glucose level, 7.6 mM; mean GHb level, 8%). Catheter blockage was the main reason for ECPII failure (74%). Mean catheter survival of each catheter, determined by actuarial analysis, was 11.7 mo and significantly decreased with subsequent implantation. SEM of the catheter tips showed deposits composed of fibrin and cells occluding the inner lumen. Factors such as age, sex, local infection, and low insulin basal rate were not found to have any incidence on the catheter survival. Placement of the catheter in the upper part of the peritoneum, however, increased catheter survival. Anti-insulin antibodies did not seem to be directly involved in blockage. CONCLUSIONS: We conclude from this long-term experience that during ECPII, catheter blockage remains the major recurring complication, probably involving a local immune-inflammatory response in the peritoneum.

Adult↗

PubMed1992

New antigenic clusters on human thyroglobulin defined by an expanded panel of monoclonal antibodies.

Twenty-seven hybridomas secreting monoclonal antibodies (mAb) directed against new antigenic clusters on human thyroglobulin (hTg) were obtained by fusion of the mouse myeloma P3-X63-Ag8 653 with spleen cells from BALB/c mice immunized with a mixture of hTg and six anti-hTg mAb with the aim of masking the corresponding antigenic clusters previously reported. Fourteen mAb were selected, produced in ascitic fluid and characterized. All these mAb were of the IgG1 subclass. Five new antigenic clusters on the hTg molecule were defined by the 14 mAb, extending the initial antigenic map of hTg to 11 clusters. These mAb were used in an attempt to probe the interaction between hTg and the autoantibodies from patients with Hashimoto's thyroiditis who do not recognize antigenic cluster II, a cluster whose recognition by anti-hTg autoantibodies is significantly associated with thyroid disorders.

Animals↗

PubMed1992

Conserved natural humoral immunity to thyroglobulin in patients with multiple myeloma.

We studied humoral immunity to human thyroglobulin (hTg) during the course of multiple myeloma (MM). In this report, we describe the anti-hTg antibody activity in the sera of patients with MM. Among 63 sera tested, 28 (44%) had IgG anti-hTg autoantibodies (aAb), 16 (25%) exhibited IgM aAb, and six (9%) had IgA anti-hTg aAb. For the majority of sera the anti-hTg autoantibody activity was associated with more than one immunoglobulin class. IgG anti-hTg antibodies were observed in 9/11 patients with IgA MM and in 19/40 patients with IgG MM. The IgM anti-hTG antibody activity was found in the sera of 11 patients with IgG MM. These results show that the anti-hTg activity in these patients is associated with residual polyclonal immunoglobulins. However, in the serum of one patient presenting a double monoclonal gammopathy (IgG and IgA lambda MM), the anti-hTg activity was carried by both the IgG lambda and the IgA lambda molecules, suggesting that in this case the activity was due to the monoclonal immunoglobulin itself. We also studied the epitopic specificity pattern of all these anti-hTg aAb. Only three sera recognized one antigenic region on hTg, suggesting that the majority of the anti-hTg aAb in MM patients were directed against antigenic regions other than those recognized by our panel of murine mAb. In conclusion, our results demonstrated that humoral immunity to hTg is maintained in MM patients. These data contrast with the well-documented suppression of immunity to foreign, especially bacterial, antigens described in MM.

Adult↗

PubMed1991

Autoimmunity to human thyroglobulin. Respective epitopic specificity patterns of anti-human thyroglobulin autoantibodies in patients with Sjögren's syndrome and patients with Hashimoto's thyroiditis.

We evaluated the epitopic specificity pattern of anti-human thyroglobulin (anti-hTg) autoantibodies from patients with primary Sjögren's syndrome (SS). All of the primary SS sera tested contained both IgG and IgM anti-hTg autoantibodies recognizing at least 1 region on hTg; in 65% of the cases, 3 or more regions were recognized. A strong recognition of region II, as is seen in Hashimoto's thyroiditis, was associated with thyroid disorder in primary SS. These results emphasize the importance of region II in autoimmune thyroid disease.

Adult↗

PubMed1991

Identification of several human urinary metabolites of 6-benzoyl benzoxazolinone by gas chromatography/mass spectrometry.

The biotransformation of 6-benzoyl benzoxazolinone (6-BB), a non-narcotic peripheral analgesic, was studied in eight healthy volunteers after oral administration of a single dose of 1 g. Urinary metabolites were extracted either with ethyl acetate at different pH values or by percolating at pH 5 through Amberlite XAD 2 ion-exchange resin. Eluates were concentrated under vacuum, purified by thin-layer chromatography and analysed by gas chromatography/mass spectrometry or direct insertion probe mass spectrometry. Metabolites were identified with reference to the mass spectra of various synthesized compounds assumed to be metabolites of 6-BB, as N-methylated or monohydroxylated compounds. Another metabolic pathway was cleavage of the benzoxazolinone heterocycle giving 2-amino-5-benzoyl phenol after hydrolysis and decarboxylation. N-methyl, N-acetyl and hydroxylated metabolites having an amino-5-benzoyl phenol structure were also found.

Adult↗

PubMed1991

Inhibition of mouse T-cell proliferation by CGRP and VIP: effects of these neuropeptides on IL-2 production and cAMP synthesis.

We compared the effect of two neuropeptides, calcitonin gene-related peptide (CGRP) and vasoactive intestinal peptide (VIP), on mitogen-induced murine splenocyte proliferation. Both neuropeptides exerted their maximal effect within 24 hr after activation by Con A. The combination CGRP-VIP caused an additive inhibitory effect on T-cell proliferation. The inhibitory effect of VIP could be correlated with a decrease in interleukin 2 (IL-2) production, whereas CGRP did not affect this production. Since we also observed an additive inhibitory effect on T-cell proliferation by the theophylline and CGRP or VIP combination, we measured the effect of each neuropeptide on intracellular cAMP production by enriched T-cells: CGRP, but not VIP, strongly stimulated cAMP synthesis. Taken together, our results indicate that inhibition of murine T-cell proliferation by CGRP and VIP is mediated by different mechanisms.

Animals↗