PubMed Health⌕ Search

Biomedical subjects

C Ménard

Publications and source records attributed to C Ménard.

At least 37 records · Page 2Linked to original sources
PubMed1997

Determination of clenbuterol in beef liver and muscle tissue using immunoaffinity chromatographic cleanup and liquid chromatography with ultraviolet absorbance detection.

Clenbuterol, a beta-agonist, was determined in samples of beef liver and muscle. The method employed an acidic aqueous extraction followed by protein precipitation. The supernatant liquid was passed through a weak cation-exchange cartridge and then through a commercially available immunoaffinity cartridge. Clenbuterol was eluted from the immunoaffinity cartridge with 80% ethanol in water. The eluate was concentrated and analysed directly by reversed-phase liquid chromatography using gradient elution and UV detection at 245 nm. Detection limits were estimated to be 0.3 ng g-1 clenbuterol. A single immunoaffinity cartridge was used for ten sample extracts with no significant loss in capacity. No organic solvents other than ethanol and methanol were employed in the procedure. Recoveries of clenbuterol from samples of beef liver and muscle spiked at 2 and 5 ng g-1 carried through the entire procedure were 63 +/- 11% (range, 53-74%) compared to pure standards. Absolute recoveries of pure standards (30 ng clenbuterol) carried through the same analytical steps were 70 +/- 5% (n = 6), the losses being primarily due to the ion-exchange step.

Adrenergic beta-Agonists↗
PubMed1997

Anal reeducation for postoperative fecal incontinence in congenital diseases of the rectum and anus.

From October 1993 to March 1996, 14 patients with anorectal disease were referred to an anal reeducation clinic. Initial evaluation allowed the authors to identify three classes of defects: lack of proprioception in the sphincters, use of synergistic muscles (gluteal) to compensate for anal dysfunction, and inversion of command by contraction, rather than relaxation, of abdominal muscles. Patients were treated by electrostimulation through an anal probe as well as biofeedback therapy coupled with home exercises. This therapy resulted in rapid correction of the abnormal motor commands and erroneous use of accessory muscles. All patients became able to isolate their continence muscles with success, with documented increase in strength, rapidity of response, and duration of contraction. The mean Kelly score went from 1.46 (range, 0 to 4.5) to 3.07 (range, 0.5 to 5.5). This physiological improvement also increased patient motivation and discipline toward continence and subsequently their quality of life.

Adolescent↗
PubMed1996

Liquid chromatographic determination of okadaic acid and dinophysistoxin-1 in shellfish after derivatization with 9-chloromethylanthracene.

The reagent 9-chloromethylanthracene was evaluated for derivatization of the diarrhetic shellfish poisons, okadaic acid and dinophysistoxin-1 (DTX-1), to form fluorescent products separable by liquid chromatography. The toxins were reacted with the reagent in acetonitrile in the presence of tetramethylammonium hydroxide for 1 h at 90 degrees C. The products were purified by using two silica solid-phase extraction cartridges before being determined by reversed-phase liquid chromatography with fluorescence detection. The results are comparable to those obtained using 9-anthryldiazomethane (ADAM) for okadaic acid and DTX-1 in mussel tissue. Detection limits were estimated to be about 70-100 ng/g hepatopancreas (equivalent to 12-20 ng/g whole tissue) for each toxin.

Animals↗
PubMed1996

Effect of Porphyromonas gingivalis on epithelial cell MMP-9 type IV collagenase production.

Porphyromonas gingivalis is reportedly capable of stimulating the expression of host cell matrix metalloproteinases (MMP), contributing to tissue destruction. However, the impact of this bacterium on specific molecules remains to be determined. In this study, we evaluate the effect of P. gingivalis on regulation of MMP-9 expression in human gingival epithelial cells (HGEC). Various inocula of P. gingivalis were added to cultures of HGEC. The effects of live bacteria, heat-killed bacteria, and outer membrane extract were analyzed. MMP-9 secretion by HGEC was evaluated by enzyme-linked immunosorbent assay. For inocula smaller than one bacterium per cell, the quantity of MMP-9 secreted by HGEC was increased in comparison to control conditions. For inocula from 2.5 to 250 bacteria per cell, an inhibition of MMP-9 secretion in a dose-response fashion was observed, with a maximum reduction (ranging from 80 to 95% in five experiments) at 50 bacteria per cell. Gelatin zymograms confirmed the decrease in MMP-9 secretion. A band of 83 kDa, corresponding to activated enzyme, was present for inocula of 0.5 to 50 bacteria. Inhibition took place without any alteration of epithelial cell viability. Heat-killed bacteria and outer membrane extract also provoked proenzyme activation but did not inhibit MMP-9 secretion. These results demonstrate a direct effect of P. gingivalis on HGEC, suggesting a specific action on the collagen renewal process at the interface between the epithelium and connective tissue.

Bacteroidaceae Infections↗
PubMed1995

Clonal diversity of the taxon Porphyromonas gingivalis assessed by random amplified polymorphic DNA fingerprinting.

A total of 97 strains of the periopathogen Porphyromonas gingivalis were collected. This collection included laboratory strains and clinical isolates of human origin with diverse clinical and geographical origins. Biological diversity was further increased by including 32 strains isolated from the oral cavities of nine different animal species. Genomic fingerprints of the 129 strains were generated as random amplified polymorphic DNAs (RAPDs) by the technique of PCR amplification with a single primer of arbitrary sequence. Four nonameric oligonucleotides were used as single primers, and the banding patterns of the DNA products separated on agarose gels were compared after ethidium ethidium bromide staining. Distance coeffients based on the positions of the major DNA fragments were calculated, and dendrograms were generated. We identified 102 clonal types (CTs) that could be assembled into three main groups by cluster analysis by the unweighted pair group method with mathematic averages. Group I (n = 79 CTs) included all 97 human strains and 6 monkey isolates. The strains in group II (n = 22 CTs) and III (n = 1 CT) were strongly differentiated from those in group I and included only strains of animal origin; they likely represent two cryptic species within the present P. gingivalis taxon. We observed that strains from Old World monkeys clustered together with the human genotype, whereas strains from New World monkeys clustered with the animal genotype. Our results with human strains also indicated that (i) the population structure is basically clonal, (ii) no dominant or widespread CT could be observed, and (iii) no relationship could be established between specific clusters of CTs and the periodontal status of the host. Our results corroborate previous findings by B. G. Loos, D. W. Dyer, T. S. Whittam, and R. K. Selander (Infect. Immun. 61:204-212, 1993) and suggest that P. gingivalis should be considered a commensal of the oral cavity acting as an opportunistic pathogen. Our results are not consistent with the hypothesis that only a few virulent clones of P. gingivalis are associated with disease.

Animals↗
PubMed1995

Isolation of Porphyromonas gingivalis strain from tubal-ovarian abscess.

An unusual case of involvement of Porphyromonas gingivalis is described. Two anaerobic isolates, identified as Fusobacterium nucleatum and P. gingivalis, were recovered from the pus of a tubal-ovarian abscess in a 35-year-old woman. Identification of the P. gingivalis isolate was confirmed by randomly amplified polymorphic DNA fingerprinting.

Abscess↗
PubMed1994

Polymerase chain reaction using arbitrary primer for the design and construction of a DNA probe specific for Porphyromonas gingivalis.

In this work, we used a novel approach for the design and construction of DNA probes which requires no knowledge of target DNA sequence. We demonstrated that species-specific genetic markers, identified as such among monomorphic, randomly amplified DNA segments generated by the polymerase chain reaction with arbitrary primer can be labelled to yield so-called "anonymous probes". We report here on the construction of such an anonymous probe, 1146 bp long, specific for the Gram-negative anaerobe Porphyromonas gingivalis, a suspected major etiologic agent of chronic periodontitis in adults.

Animals↗
PubMed1992

Application of polymerase chain reaction with arbitrary primer (AP-PCR) to strain identification of Porphyromonas (Bacteroides) gingivalis.

Several molecular methods are currently available for identification and discrimination of bacterial strains within the same species, which vary in efficiency and required labour. Here we applied a novel method for fingerprinting genomes, called arbitrarily primed PCR (AP-PCR), to the delineation of strains within the species Porphyromonas gingivalis. Using a single primer on a set of nine strains, nine simple distinct banding patterns, indicative of genetic polymorphism, were observed. Common amplicons and amplicons shared by only some strains were also observed, the latter suggesting that AP-PCR can be used to generate polymorphic markers. Genomic fingerprinting obtained by AP-PCR was independent of the quality of DNA. Assays performed directly using whole cells as a source of DNA template indicated that AP-PCR from colony is a quick, simple and accurate procedure.

Base Sequence↗
PubMed1992

Human neutrophils produce high levels of the interleukin 1 receptor antagonist in response to granulocyte/macrophage colony-stimulating factor and tumor necrosis factor alpha.

Neutrophils, an abundant cell type at sites of inflammation, have the ability to produce a number of cytokines, including interleukin 1 (IL-1), IL-8, granulocyte-macrophage colony-stimulating factor (GM-CSF), and tumor necrosis factor alpha (TNF-alpha). In this study, we have examined the ability of human neutrophils to produce the IL-1 receptor antagonist (IL-1Ra), a 17-23-kD protein recently isolated and cloned from macrophages. Since IL-1Ra has been shown to inhibit both the in vitro and in vivo effects of IL-1, its production by large numbers of tissue-invading neutrophils might provide a mechanism by which the effects of IL-1 are regulated in inflammation. Using antibodies that are specific for IL-1Ra and a cDNA probe encoding for this protein, we were able to show that neutrophils constitutively produce IL-1Ra. However, after activation by GM-CSF and TNF-alpha, IL-1Ra was secreted into the extracellular milieu where it constituted the major de novo synthesized product of activated neutrophils. None of a large array of other potent neutrophil agonists were found to affect the production of IL-1Ra by neutrophils. Quantitative measurements by enzyme-linked immunosorbent assay revealed that intracellular IL-1Ra is in eightfold excess of the amount secreted in supernatants when studying nonactivated neutrophils. However, in GM-CSF- and TNF-alpha-activated cells, this difference was reduced to values between four- and fivefold, as virtually all of the de novo synthesized IL-1Ra was secreted. In activated cells, the intracellular content of IL-1Ra was found to be in the 2-2.5-ng/ml range per 10(6) neutrophils, whereas levels reached the 0.5-ng/ml range in supernatants. This would imply that IL-1Ra is produced in excess of IL-1 by a factor of at least 100, an observation that is in agreement with the reported amounts of IL-1Ra needed to inhibit the proinflammatory effects of IL-1. Neutrophils isolated from an inflammatory milieu, the synovial fluid of patients with rheumatoid arthritis, were found to respond to GM-CSF and TNF-alpha in terms of IL-1Ra synthesis, indicating that the in vitro observations made in this study are likely to occur in an inflammatory setting in vivo.

Arthritis, Rheumatoid↗
PubMed1991

Confirmation of domoic acid in shellfish using butyl isothiocyanate and reversed-phase liquid chromatography.

A simple chemical confirmatory technique has been developed for domoic acid, a neurotoxic amino acid of marine origin. After extraction with water-methanol, the domoic acid-containing extract is analysed directly by reversed-phase liquid chromatography with UV absorption detection at 242 nm. For confirmation of positive results an aliquot of the extract is evaporated to dryness and reacted with butyl isothiocyanate to form a thiourea derivative which elutes later than underivatized domoic acid. No additional sample cleanup is required in order to carry out the derivatization for conformation of domoic acid at the Canadian 20 micrograms/g guideline level in shellfish. In mussel extract, domoic acid was converted to the thiourea derivative with a yield of 86-91% compared to a pure standard carried through the same reaction. The detection limit for the derivative was about 5-10 micrograms/g of equivalent domoic acid in extracts of mussels, clams or oysters.

Animals↗
PubMed1989

Thrombospondin and fibronectin are synthesized by neutrophils in human inflammatory joint disease and in a rabbit model of in vivo neutrophil activation.

Using 35S-methionine metabolic labeling, we studied de novo synthesis and secretion of proteins by activated polymorphonuclear neutrophils (PMN) from two different sources. PMN isolated from inflammatory synovial fluid of patients with inflammatory joint disease were first analyzed. The protein synthetic activity of these cells was compared with that of nonactivated PMN isolated from the peripheral blood of the same patient. Similar studies were conducted on glycogen-activated PMN from the peritoneal cavity of rabbits and results were compared with nonactivated peripheral blood PMN isolated from the same rabbit. Cells were labeled for a period of 16 to 20 h and supernatants were analyzed by one and two dimensional gel electrophoresis. In both models, the activated PMN showed a marked increase in the synthesis and secretion of thrombospondin as identified by immunoisolation with antibodies to this protein. The production of thrombospondin by activated cells paralleled a similar increase in production of another extracellular matrix and cell adhesion protein, fibronectin. The proportion of thrombospondin synthesis and secretion relative to total protein was approximately 1% in both human- and rabbit-activated PMN. For fibronectin, this proportion was in the 0.02% range. Although fibronectin mRNA accumulation in activated PMN could be demonstrated by Northern blots, we were not able to obtain similar results for thrombospondin mRNA. This could be caused by the rapid turnover of this transcript because it is known to contain an adenine uridine-rich 3' untranslated sequence. We conclude that activated PMN are capable of producing thrombospondin. Furthermore, glycogen-activated rabbit peritoneal fluid PMN represent a valuable and relevant source of activated PMN for studying the protein synthetic events of these cells in the context of inflammation.

Animals↗
PubMed1989

Liquid chromatographic determination of domoic acid in shellfish products using the paralytic shellfish poison extraction procedure of the association of official analytical chemists.

Domoic acid, the recently discovered toxic substance found in contaminated mussels from an area in eastern Prince Edward Island (Canada) was extracted from mussel tissue using the procedure of the Association of Official Analytical Chemists for paralytic shellfish poisons. This involved a 5-min boiling of the sample with 0.1 M hydrochloric acid then cooling and centrifuging. An aliquot of the supernatant was diluted ten to one-hundred times with water, filtered and analysed by reversed-phase liquid chromatography with a mobile phase consisting of acetonitrile-water (12:88) at pH 2.5 and an absorption wavelength of 242 nm. The detection limit was about 0.5 mg/kg domoic acid in seafood samples. The technique was successfully applied to a variety of commercially purchased shellfish and shellfish products.

Animals↗
PubMed1984

The role of fibronectin in the cryoprecipitation of monoclonal cryoglobulins.

We have recently reported that fibronectin is a component of mixed cryoglobulins and is responsible in large part for cryoprecipitate formation. We have now extended our studies to serum cryoprecipitates formed in the presence of monoclonal cryoglobulins in patients with lymphoproliferative diseases in order to investigate for a possibly similar influence of fibronectin on cryoprecipitation. Results have shown that these cryoprecipitates contain fibronectin in proportions varying between 10% and 14% of their total protein content. Furthermore, SDS-polyacrylamide gel electrophoresis revealed that next to the cryoglobulins, fibronectin constitutes the second major component of the cryoprecipitates. Depletion of the sera in fibronectin prior to exposure to 4 degrees C, markedly reduced cryoprecipitation of the cryoglobulins, whereas reconstitution in fibronectin restored it. These studies support and extend our previous findings showing the important influence exerted by fibronectin on the process of immunoglobulin cryoprecipitation.

Chemical Precipitation↗
PubMed1971

[Not Available].

Explore the source record for details and available documents.

France↗