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Biomedical subjects

M Bastide

Publications and source records attributed to M Bastide.

At least 19 recordsLinked to original sources
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↗
PubMed1991

Biotransformation study of para-substituted phenylpiperazines in beagle dogs by gas chromatography-mass spectrometry.

1. Beagle dogs were treated orally (10 mg/kg) with para-chloro-, para-fluoro- and para-methyl-phenylpiperazine derivatives, and urine was collected for 72 h after treatment. 2. Metabolites were extracted, converted into trimethylsilyl (TMS) derivatives and examined by g.l.c.-mass spectrometry. 3. The metabolites fall into two main groups, N-desphenylated metabolites, which result from N-desphenylation, and N-phenyl metabolites. 4. Two kinds of hydroxylated metabolites were found. Some lost the original para substituent (Cl, F or CH3); others retained it. 5. These results are consistent with the NIH shift reaction.

Animals↗
PubMed1990

Prevention of Clostridium difficile-induced experimental pseudomembranous colitis by Saccharomyces boulardii: a scanning electron microscopic and microbiological study.

The ability of Saccharomyces boulardii to protect mice against intestinal pathology caused by toxinogenic Clostridium difficile was studied. Different regions of the intestine of experimental mice were prepared for observation by scanning electron microscopy or homogenized for C. difficile enumeration and quantification of toxin A by enzyme immunoassay and toxin B by cytotoxicity. The test group was treated for 6 d with an S. boulardii suspension in drinking water and challenged with C. difficule on day 4. The three control groups were: axenic mice, mice treated with only S. boulardii and mice only challenged with C. difficile. The results showed that: (i) 70% of the mice infected by C. difficile survived when treated with S. boulardii; (ii) the C. difficile-induced lesions on the small and large intestinal mucosa were absent or markedly less severe in S. boulardii-treated mice; and (iii) there was no decrease in the number of C. difficile but rather a reduction in the amount of toxins A and B in S. boulardii-treated mice.

Animals↗
PubMed1989

Significance of the recognition of certain antigenic regions on the human thyroglobulin molecule by natural autoantibodies from healthy subjects.

We have evaluated the epitope specificity of natural antihuman thyroglobulin (hTg) autoantibodies (aAb) in the plasma of healthy individuals. By an indirect ELISA technique, we selected 56 plasma samples with high anti-hTg antibody activity and used the IgG fraction isolated from these plasma to study the antigenic domains on the hTg molecule recognized by the natural anti-hTg aAb. A panel of 15 mAb, coupled to alkaline phosphatase and recognizing six regions (I to VI) on the hTg molecule, served to identify the domains recognized by the natural anti-hTg aAb using a competitive ELISA procedure. A total of 26 of the IgG fractions was found to interact with at least one of the regions defined by our battery of mAb. Region V was recognized by the majority of the IgG fractions. Interestingly, region II was rarely recognized by the same IgG fraction that reacted with region V. Inasmuch as we have previously shown that region II is mainly recognized by aAb in the serum of subjects with various thyroid disorders, we propose that recognition of region V reflects the normal physiologic state of the immune system with respect to the hTg molecule.

Adolescent↗
PubMed1989

[In vitro effect of itraconazole against various species of Candida].

The authors compared the in vitro antifungal activity of itraconazole to that of miconazole against various species of Candida. The MIC of 88 strains of Candida (C. albicans, C. guilliermondii, C. parapsilosis, C. glabrata) was determined by the agar dilution method using casitone medium at pH 5.5-5.6 for miconazole and pH 7.2-7.4 for itraconazole. C. albicans and C. glabrata were found to be less sensitive in vitro to itraconazole than to miconazole; the contrary was observed for C. parapsilosis. The sensitivity of C. guilliermondii to these antifungal agents was similar. The MIC 50, MIC 90 and G.MIC values for itraconazole with respect to 42 strains of C. albicans was 0.10, 1.4 and 0.138 micrograms ml-1, respectively; the MIC 90 and G.MIC values for miconazole were 0.5 and 0.021 micrograms ml-1, respectively. The effect of itraconazole on the ultrastructure of C. albicans yeast cells and spheroplasts was studied by scanning electron microscopy. This triazole molecule modified the cell wall of C. albicans, caused cell stretching and provoked defective separation between mother and daughter cells. Itraconazole altered the cytoplasmic membrane of the spheroplasts causing them to have a "spongy" appearance. Yeast cells treated with itraconazole appeared to liberate their spheroplast with difficulty.

Candida↗
PubMed1988

[Comparative action of 8 azole derivatives against Candida albicans: fungistatic action and cytologic study by scanning electron microscopy].

The authors compared the in vitro antifungal activity of eight imidazole derivatives (clotrimazole, econazole, isoconazole, ketoconazole, miconazole, oxiconazole, terconazole, tioconazole) against 42 strains of Candida albicans by the agar dilution method using casitone medium. The geometric (G) mean MIC values, the MIC 90 and the MIC 50 values and the corresponding standard deviations of each antifungal agent were determined. The G-MIC values were found to be in the range of 0.008-0.390 micrograms ml-1. The effects of these eight antifungal agents on the ultrastructure of C. albicans yeast cells and spheroplasts were studied by scanning electron microscopy (SEM). The results showed a good correlation between the lesions observed and the structure of the imidazole derivatives tested. On the basis of the SEM results, the compounds could be divided into three groups: (1) ketoconazole and terconazole; (2) econazole, isoconazole, miconazole, oxiconazole and tioconazole; (3) clotrimazole.

Antifungal Agents↗
PubMed1988

Immunomodulatory activity of low doses of interferon alpha,beta in mice.

We evaluated the immunomodulatory effects of mouse interferon (IFN) alpha, beta on the specific humoral response of mice (OF1) to sheep erythrocytes and on cell-mediated immunity by studying the cytotoxic activity of allospecific T-cells (CTL) and natural killer (NK) cells. Four injections of 2 IU of IFN before administration of the antigen did not have an effect on the humoral response, whereas 4 injections of 2 x 10(-10) IU of IFN caused a significant increase in the number of antibody-secreting cells. When C57BL/6 mice were treated with 5 injections of 2 IU or 2 x 10(-10) IU of IFN before the second immunization with allogeneic cells, the CTL activity was not modified; but when the mice were also treated with 2 x 10(-10) IU 3 times after immunization, this activity was strongly stimulated. IFN caused a decrease in the activity of CTL from NZB at both doses. The cytotoxic response of NK cells was stimulated by 5 injections of 2 IU of IFN in both strains of mice. The results of our study suggest that very low doses of IFN alpha,beta have immunopharmacologic activity.

Adjuvants, Immunologic↗
PubMed1987

Antigenic domains on the human thyroglobulin molecule recognized by autoantibodies in patients' sera and by natural autoantibodies isolated from the sera of healthy subjects.

We determined the regions on the human thyroglobulin (hTg) molecule recognized by anti-hTg autoantibodies (aAbs) in the sera of patients with Hashimoto's thyroiditis, Graves' disease, and thyroid carcinoma and by anti-hTg natural aAbs isolated from the sera of healthy subjects. Fifteen anti-hTg monoclonal antibodies (MAbs) directed against six distinct antigenic regions were used for this study. The anti-hTg aAbs in the patients' sera recognized mainly region II and occasionally region IV. The natural aAbs were present in the serum at low concentrations; consequently, we isolated and concentrated them for this investigation. The isolated natural aAbs inhibited the interaction of the anti-hTg MAbs with the majority of the antigenic regions identified. Region II was not well recognized, however, by these natural aAbs. This difference in specificity between the anti-hTg aAbs and the anti-hTg natural aAbs may have diagnostic significance.

Autoantibodies↗
PubMed1979

Taxonomic significance of yeast sphaeroplast release after enzymatic treatment of intact cells.

Treatment of whole yeast cells with a mixture of a reducing agent and 1,3-beta-glucanase isolated from Basidiomycete QM806 led to the production of sphaeroplasts from ascomycetes, from some fungi imperfecti, but not from basidiomycetes. Association of 1,3-beta-glucanase with a second enzyme, 1,4-alpha-glucanase, from Trichoderma viride, was required for sphaeroplast release from some, but not all, basidiomycetes and fungi imperfecti. The ability of yeast cells to liberate sphaeroplasts following appropriate enzymic treatment is proposed as a taxonomic criterion for differentiating basidiomycetous from ascomycetous yeasts and for classifying fungi imperfecti yeasts.

Ascomycota↗
PubMed1976

[Action of various beta(1-3)-D-glucanases on the wall of yeasts: taxonomic applications].

Purified beta-(1-3)-D-glucanases (from Aspergillus nidulans, Badidiomycetes sp. QM 806, Trichoderma viride) are used to release protoplasts from various yeasts. Two of them may prove taxonomic correlation. The enzyme of Basidomycetes sp. releases protoplasts from Ascomycetes, the enzyme of T. viride releases protoplasts from Ascomycetes and Heterobasidiomycetes; none of them acts on the Basidiomycetes.

Ascomycota↗