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Biomedical subjects

C Mouton

Publications and source records attributed to C Mouton.

At least 73 records · Page 4Linked to original sources
PubMed1990

Immunoreactivity in humans of Bacteroides gingivalis hemagglutinating adhesin HA-Ag2.

A rabbit antiserum monospecific for HA-Ag2, a hemagglutinating adhesin of Bacteroides gingivalis, was used as a reference to screen sera from 8 patients with chronic periodontitis and 6 normal subjects for specific antibodies. The monospecific antiserum detected a complex of 2 polypeptides with molecular weights of 43 and 49 kDa in an outer membrane preparation of B. gingivalis. All human sera reacted with one or both polypeptides in at least one of the isotypes (IgG, IgA and IgM) tested, indicating that HA-Ag2 is an immunodominant antigen. Although the 2 components of HA-Ag2 are antigenically similar, a trend toward preferential reactivity of IgM with the 49 kDa component was observed. This suggests that an epitope-specific mechanism of regulation of the immune response to B. gingivalis in humans may exist via the HA-Ag2 complex.

Antigens, Bacterial↗
PubMed1990

Molecular size variation of the hemagglutinating adhesin HA-Ag2, a common antigen of Bacteroides gingivalis.

The array of Bacteroides gingivalis W83 antigens revealed by crossed immunoelectrophoresis includes one antigen that is associated with an erythrocyte-binding capacity, termed the hemagglutinating adhesin HA-Ag2. This antigen was excised from crossed-immunoelectrophoresis plates to produce two polyclonal antisera, VL 011 and WL 303, whose restricted specificity for HA-Ag2 was assessed using crossed immunoelectrophoresis, crossed immunoelectrophoresis with an intermediate gel, and crossed immunoaffinoelectrophoresis. Both antisera, when used to probe blots of an EDTA cell surface extract of B. gingivalis W83, reacted with two bands, at 33 and 38 kDa, which were also detected by a monoclonal antibody (Naito et al. 1985. Infect. Immun. 50: 231-235), specific for a hemagglutinin of B. gingivalis. Antiserum WL 303 was used to examined by immunoblotting the distribution of HA-Ag2 among a variety of human and animal strains of B. gingivalis. All human strains tested showed two major bands at 33 and 38 kDa in the EDTA cell surface extract, and at 43 and 49 kDa in outer membrane preparations. Only one band, at 29 kDa, was detected in EDTA cell surface extracts from the animal strains, while the outer membrane preparation of a single strain showed a positive reaction. We concluded that HA-Ag2 is an antigen common to human and animal strains of B. gingivalis and that its subunits may show heterogeneity in apparent molecular mass.

Adhesins, Bacterial↗
PubMed1990

[A comparison of culture and immunofluorescence technics in the study of Bacteroides with black pigmentation].

The aim of that study was to compare culture and immunofluorescence (IF) methods to determine whether B. gingivalis and other B.P.B. can be detected in subgingival plaque of children. Samples were collected from the lingual sulcus of mandibular incisors, dispersed and diluted from 1 to 10(-5); 15 microliters of each dilution were plated on Trypticase soja agar and Todd-Hewitt agar supplemented with blood, Vit K 1 and hemin. The same dilutions were smeared on glass slides for indirect IF using an species-specific polyclonal rabbit whole cell antiserum to B. gingivalis ATCC 33 277. Representative colonies producing brown-to-black pigment were isolated, purified and further characterized. Using culture, BPB were detected in 46% of children (19/41). B. gingivalis was cultured from 6 children. Using immunofluorescence test (Fluotec*), 90% of 309 children 3 years old and more harbour detectable B.P.B., but B. gingivalis don't react with that test. B. gingivalis were detected by immunofluorescence in 72% of children (30/41) in the incisor plaque.

Adolescent↗
PubMed1990

Caries predictors suitable for mass-screenings in children: a literature review.

This paper reviews the predictors used to identify children and adolescents at high risk of developing dental caries. They are presented with their degree of association with caries, their validity as screening tests and their methods of determination. The most promising predictors are identified and caries prediction models are also briefly reviewed. The article concludes with some comments about weaknesses encountered in the conduct of screening studies and makes some suggestions for improving the validity of the prediction models.

Adolescent↗
PubMed1990

Nonallergic rhinitis with eosinophilia syndrome a precursor of the triad: nasal polyposis, intrinsic asthma, and intolerance to aspirin.

Fifty-two cases of perennial rhinitis were studied, leading to the diagnosis of seven cases of nonallergic rhinitis with eosinophilia syndrome (NARES) a frequency of 13.5%. Symptoms of nasal hyperreactivity involving sneezing, rhinorrhea, nasal obstruction and pruritus were more severe than in other types of rhinitis. The frequency of hyposmia was very specific to NARES. Nasal endoscopy and sinus CT revealed an evolution towards nasal polyposis in four patients. The nasal challenge to house dust mites showed the absence of any increase in local eosinophilia. Bronchial hyperreactivity to carbachol occurred in one case. There was no case of intolerance to aspirin. There was particular adrenergic hyperreactivity among the seven patients, evidenced by study of the reactivity of the cardiovascular alpha and beta receptors. The authors emphasize the features that are shared by NARES and by the triad, which suggest that NARES is the early phase of the triad. They advance the pathogenic hypothesis of an autonomic nervous system dysregulation with a predominating adrenergic hyperreactivity. Inflammatory effects of local release of neurotransmitters induce a switch from a neurogenic to a self-sustaining inflammation. Tissue eosinophilia is regulated by chemical attractants and activating substances of various origins and plays a major part in the chronic inflammatory state.

Adolescent↗
PubMed1989

Salivary IgA is a weak stress marker.

Several studies support the hypothesis that psychological stress may negatively affect immunocompetence. The present study sought to determine whether a relationship can be established between a measure of psychological state of stress and level of immunoglobulin of the A class (IgA) in saliva. To this end, 44 dentistry students were tested on four occasions; two occasions were stress inductive (examination situation), and two occasions were free of any academic stressor. At each session, the participants were asked to fill out the stress rating instrument, and unstimulated whole saliva samples were obtained. Salivary IgA was measured by a microplate Enzyme Linked Immunosorbent Assay (ELISA). A significant difference in the level of salivary IgA was observed only for the most polarized contrast, ie, between final exam and end of summer vacation (p less than .01). A weak negative correlation between the level of salivary IgA and the stress rating was observed (r = -0.25) only at the final exam. Our results suggest that assaying immunoglobulin A in saliva to measure stress may not be as useful in psychophysiological research as expected.

Adult↗
PubMed1989

Immunochemical identification and preliminary characterization of a nonfimbrial hemagglutinating adhesin of Bacteroides gingivalis.

A cell-bound hemagglutinating adhesin (HA-Ag2) of Bacteroides gingivalis was identified by crossed immunoaffinity electrophoresis as one of the common antigens of the species. A polyclonal antiserum with a restricted specificity for HA-Ag2 was produced by immunizing with the relevant immunoprecipitate excised from crossed-immunoelectrophoresis gels. The immunoglobulin G fraction of this monospecific antiserum inhibited hemagglutination. The antiserum was used against a cell surface extract of B. gingivalis in immunoblotting experiments, and we detected two antigens with apparent molecular masses of 33 and 38 kilodaltons in B. gingivalis ATCC 33277 and W83. Monoclonal antibody, C1.17, produced in another laboratory against B. gingivalis 381 and characterized as showing reactivity with a hemagglutinin of this strain (Y. Naito, K. Okuda, T. Kato, and I. Takazoe, Infect. Immun. 50:231-235, 1985), was also used to produce immunoblots of extracts of strains ATCC 33277 and W83. The apparent molecular masses of the major polypeptides recognized by monoclonal C1.17 in the immunoblots were the same as those detected by the polyclonal monospecific antiserum, i.e., 33 and 38 kilodaltons. Significantly, none of the polypeptides identified in this study corresponded to the polypeptide appearing in the 41- to 43-kilodalton region and identified by Yoshimura and co-workers (F. Yoshimura, K. Takahashi, N. Yoshinobu, and T. Suzuki, J. Bacteriol. 160:949-957, 1984) as the fimbrial protein characteristic of the species. Enzyme-linked immunosorbent assay inhibition experiments with the monospecific antiserum indicated that the cell surface extracts from strains ATCC 33277 and W83 were strong inhibitors, whereas the fimbria-enriched preparations from both strains failed to inhibit binding of antibodies to the cell surface antigens. As a whole, our study indicates that a nonfimbrial surface protein complex demonstrating erythrocyte-binding capacity, HA-Ag2, is common to three strains of B. gingivalis and is composed of at least two associated polypeptides with apparent molecular masses of 33 and 38 kilodaltons which share at least one antigenic determinant.

Antibodies, Bacterial↗
PubMed1988

[Leukocyte histamine liberation tests for the diagnosis of anaphylactic reaction to curare-like agents].

Anaphylaxis to myorelaxants is the main etiology of adverse reactions to anesthetics and adjuvants. The diagnosis relies on skin tests--prick or intradermal tests--radio-immunoassays for series specific IgE, human basophil degranulation tests and leucocyte histamine++ release. 28 patients with an anaphylaxis to myorelaxants have been studied, using the two tests. Skin tests are the more specific and accurate ones. ARIA using a quaternary ammonium hydrated gel, is highly specific and its sensitivity reaches 80%. The leucocyte histamine release may be interest in evaluating anaphylaxis especially when another drug might be involved. The sensitivity of HBDT is low, indicating that HBDT is to be discarded as far as other tests have been developed, for myorelaxants. However, its usefulness for other drugs has to be compared to leucocyte histamine release.

Anaphylaxis↗
PubMed1987

Selection for Streptococcus mutans with an altered xylitol transport capacity in chronic xylitol consumers.

The effect of long-term consumption of refined xylitol on the natural populations of S. mutans in the human oral cavity has been investigated. Fifty-four S. mutans strains were isolated from adults and children who had been consuming commercial food products containing xylitol for a period of from 1 1/2 to 10 years. Twenty isolates were also obtained from control subjects who had never consumed xylitol-containing commercial food products. The inhibitory effect of xylitol on the isolated strains was determined by monitoring growth on glucose in the presence or absence of xylitol. This was used to define the sensitivity of each isolate to xylitol. Phosphoenolpyruvate:sugar phosphotransferase (PEP-PTS) activities were measured by means of the soluble and membrane fractions prepared from strains from both study populations. It was found that 87% of the fresh isolates from xylitol consumers were xylitol-resistant (XR), compared with only 10% of the strains isolated from the control subjects. The XR strains had low constitutive fructose PTS activity and very low xylitol-phosphorylating capacity. The xylitol-sensitive (XS) strains, however, had much higher levels of constitutive fructose PTS activity and phosphorylated xylitol 16 times more rapidly than did the XR strains. Evidence for the phosphorylation of xylitol by a fructose PEP-PTS in the XS strains was obtained. The growth inhibition by the intracellular accumulation of non-metabolizable toxic xylitol phosphate and its prevention by the presence of fructose are discussed.

Adolescent↗
PubMed1986

Human and animal serotypes of Bacteroides gingivalis defined by crossed immunoelectrophoresis.

The antigenic complexity of three strains of Bacteroides gingivalis and four strains resembling B. gingivalis isolated from animals was analyzed and compared by crossed immunoelectrophoresis. Thirteen antigens of the human biotype were present in all human strains and six antigens of the animal biotype were present in all animal strains, indicating a marked serological homogeneity within each biotype. Four antigens cross-reacting between the human B. gingivalis and the animal strains were identified. This antigenic relatedness defined the serological homogeneity of the two biotypes within the species and allowed recognition of four species-specific antigens. Two antigens specific to the human strains and two antigens specific to the animal strains were identified, indicating that serotype-specific antigens can distinguish each biotype. It is thus proposed that the oral, black-pigmented asaccharolytic Bacteroides strains of animal origin be classified as catalase-positive variants of B. gingivalis. It is also proposed that two serotypes be recognized within the species B. gingivalis. Serotype 1 includes the catalase-negative human biotype, and serotype 2 includes the catalase-positive animal biotype.

Animals↗
PubMed1985

[Anaphylaxis to muscle relaxants. Predictive value of intradermal tests and study of crossed anaphylaxis].

37 patients were studied, all of whom presented with anaphylaxis to a muscle relaxant. The diagnosis was made after simultaneous intradermal testing (IDT), human basophil degranulation tests (HBDT) and Prausnitz-Küstner tests (PK) of passive cutaneous anaphylaxis. Three tests were positive in 6 patients, both IDT and PK in 9, and both IDT and HBDT in 8. In 14 patients, the IDT, repeated twice, were positive both times. A search for crossed anaphylaxis to the other muscle relaxants was carried out in all the patients during a second series of tests, a few months to years after the first one. The drugs tested, at dilutions of the pharmaceutical preparation of 10(-3) or more, were: suxamethonium, gallamine, alcuronium, pancuronium, vecuronium, d-tubocurarine. The reliability of IDT in the diagnosis of anaphylaxis is discussed in terms of the small reactive concentration, the producibility of the tests, the one HBDT that did become positive later, and in one case the occurrence of shock by crossed anaphylaxis. Skin reactivity seemed to remain constant with time, so allowing the use of IDT as a diagnostic tool, in cases of old anaphylactoid shocks, occurring during general anaesthetics. The frequency of crossed anaphylaxis was assessed to be about 84%. The sensitivity to one or other drugs varied with each patient. Pancuronium and vecuronium appeared to be the least likely drugs to cause crossed anaphylaxis. The predictive use of these tests is discussed. It is also suggested that muscle relaxants with only one quaternary ammonium group should be used, this chemical characteristic probably reducing the risks of sensitization.

Adolescent↗
PubMed1985

[Change in skin reactivity in anaphylaxis to muscle relaxants and hypnotics after administration of anti H1, anti H2 and tritoqualine].

Inhibition of allergic skin reactivity was studied by the technique of thresholds in 35 patients presenting with an anaphylaxis to muscle relaxants. This method was useful to determine the anti-histamine or anti-anaphylactic effects of different substances. The best results were obtained with hydroxyzine. Associating it with an anti H2 drug (cimetidine or ranitidine) did not improve these results. Skin reactivity was never entirely abolished. This confirmed that no premedication could avoid the occurrence of an anaphylactic shock, or even reduce its magnitude. However, premedicating before general anaesthesia with anti H1 and anxiolytic drugs must be continued for all high risk patients: the prevention of non-specific histamine release appeared to be much more efficient than that of anaphylaxis.

Anaphylaxis↗
PubMed1984

Immunogold electron microscopy of surface antigens of oral bacteria.

Colloidal gold particles 3-6 nm in diameter were prepared and stabilized with the IgG fraction of polyspecific rabbit antisera produced against four different oral bacteria. The immunogold markers were used in homologous reactions to label the bacteria in a preembedding procedure for electron microscopy. An indirect immunofluorescence procedure was concurrently used to optimize the labelling conditions before observation with the electron microscope. The immunogold markers labelled fibrillar structures extending outward 50-275 nm from the Gram-positive cell envelopes and a fuzzy 5-10 nm thick capsulelike layer on the outer aspect of Bacteroides gingivalis. The immunogold method appears to be a simple, rapid, and inexpensive procedure suitable for the study of bacterial surface antigens and can be upgraded with the use of monospecific antibodies.

Animals↗
PubMed1984

Role of lipoxygenase products in murine pulmonary granuloma formation.

Various arachidonic acid (AA) metabolites are known to regulate immune cell function(s) and dictate the progression of both acute and chronic inflammatory reactions. Using a model of Schistosoma mansoni egg-induced hypersensitivity granulomas, we have delineated the in vivo effects of inhibitors of cyclooxygenase (CO) and lipoxygenase (LO) pathways on granuloma development and granuloma macrophage I-region-associated (Ia) antigen expression. In addition, by high performance liquid chromatography (HPLC) we have profiled the metabolism of AA by macrophages that are isolated from granulomatous foci, and have biochemically characterized the in vitro specificity and activity of selected CO and LO inhibitors. The development of hypersensitivity-type pulmonary granulomas in mice was dramatically suppressed by inhibitors with anti-LO activity (nordihydroguairetic acid (NDGA), nafazatrom, and BW755c) in a dose-dependent manner, while indomethacin, which is primarily CO-selective, had no significant effect. Furthermore, NDGA and nafazatrom profoundly arrested the normal progression of preformed granulomatous lesions. The inhibitors of the LO pathway also suppressed the in vivo kinetics of Ia antigen expression by granuloma macrophages. In contrast, indomethacin augmented Ia-antigen expression. The major AA metabolites that were synthesized by the granuloma macrophages were shown to be leukotriene C4 and mono-hydroxyeicosatetraenoic acids. HPLC analysis of AA metabolites from granuloma macrophages that were treated with the various inhibitors confirmed that indomethacin was most CO-selective and NDGA most LO-selective. Nafazatrom and BW755c inhibited AA metabolism by both pathways. Notably, high concentrations of the compounds (5 X 10(-5) M) tended to suppress all products. Our results suggest that LO products may be important in the generation and maintenance of immune granulomatous inflammatory responses.

Animals↗