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Biomedical subjects

B Dupont

Publications and source records attributed to B Dupont.

At least 199 records · Page 11Linked to original sources
PubMed1992

Isolation of Cryptococcus neoformans var. gattii from an Asian patient in France: evidence for dormant infection in healthy subjects.

We report the first case of cryptococcosis due to Cryptococcus neoformans var. gattii in France. This Cambodian, non-AIDS patient had been living in France for 23 years when he developed cryptococcosis due to C. neoformans serotype B in 1985. It is possible that he was infected back in Asia or several months before, in Zaire, where he lived between 1981 and 1984. To our knowledge, this is the second case providing clinical evidence for reactivation of latent infection with C. neoformans. The mechanism is probably similar to that for C. neoformans var. neoformans.

Adult↗
PubMed1992

In vitro antifungal activity of sertaconazole.

The antifungal activity of 7-chloro-3-[1-(2,4-dichlorophenyl)-2-(1H- imidazol-1-yl)ethoxy-methyl]benzo[b]thiophene (sertaconazole, FI-7045, CAS 99592-32-2) versus miconazole has been studied in vitro against yeast-like fungi, dermatophytes and other filamentous fungi. Candida albicans was very sensitive to sertaconazole both in serotype A and serotype B strains (MIC = 0.21 micrograms/ml). Sensitivity of Candida non albicans species (MIC = 0.17 microgram/ml), Torulopsis (MIC = 0.09 microgram/ml) and Trichosporon (MIC = 0.09 microgram/ml) was also remarkable. For dermatophytes, partial inhibitions were observed at concentrations of 0.04 and 0.09 microgram/ml, the 50% inhibition ranging between 0.36 and 12.56 micrograms/ml for most strains. Filamentous opportunistic fungi were less sensitive to azoles, although sertaconazole MICs were lower than those of miconazole. Sertaconazole also proved to possess a remarkable fungicidal activity on all strains of Candida albicans under study.

Antifungal Agents↗
PubMed1991

Pharmacokinetics of R 82913 in patients with AIDS or AIDS-related complex.

R 82913, a tetrahydroimidazobenzodiazepinthione (TIBO) derivative with potent activity against human immunodeficiency virus 1 (HIV-1) in vitro, was given to 22 patients with AIDS or AIDS-related complex in a dose-escalating pilot study. Doses of 10 to 300 mg administered daily by intravenous infusion were well tolerated for up to 50 weeks, with no haematological or biochemical evidence of toxicity. Mean OKT4 cell count rose slightly during the second month of treatment when higher steady-state plasma concentrations of the drug were achieved. Median p24 antigen concentration fell by 41% during the first month of therapy. When the rise in p24 antigen before therapy was compared to the fall during treatment, end-point analysis showed a significant difference (p less than 0.03). The combination of potent antiretroviral activity in vitro and the observed effect on HIV p24 antigen and absence of toxicity in vivo indicate that R 82913 and related TIBO derivatives merit further study in the treatment of retroviral infections.

AIDS-Related Complex↗
PubMed1991

The CD28 ligand B7/BB1 provides costimulatory signal for alloactivation of CD4+ T cells.

Activation via the T lymphocyte cell surface molecule CD28 provides a potent amplification signal for interleukin 2 (IL-2) production in several in vitro systems. The B lymphocyte activation antigen, B7/BB1, is a natural ligand for CD28. Here we investigate the role of CD28 and B7/BB1 in primary activation of CD4+ T lymphocytes stimulated with allogeneic B lymphoblastoid cell lines. A subset of peripheral CD4+ T cells that is unresponsive to crosslinking of CD3/T cell receptor (TCR) with CD3 monoclonal antibody (mAb) does proliferate in response to allogeneic B lymphoblasts. TCR binding to allogeneic major histocompatibility complex antigens was an absolute requirement for activation of these cells because mAbs to either CD3 or human histocompatibility leukocyte antigen (HLA) class II completely inhibited activation. CD28 and B7/BB1 antibodies inhibited T cell proliferation 90% and 84%, respectively. Similar results were obtained with the total CD4+ T lymphocyte population. Crosslinking of HLA-DR antigens on small, resting B cells induced rapid expression of B7/BB1, which peaked at 6 h and returned to baseline levels within 18 h. These data demonstrate that CD28-B7/BB1 binding provides an important early second signal for alloactivation of CD4+ T lymphocyte by B lymphoblasts. The results also suggest that T cells interacting with allogeneic resting B cells may induce B7/BB1 expression in the alloantigen-presenting cell as a consequence of interaction between the TCR and class II molecules.

Antibodies, Monoclonal↗
PubMed1991

Comparative study of azithromycin and amoxicillin/clavulanic acid in the treatment of lower respiratory tract infections.

Forty-eight patients with acute bronchitis and four with pneumonia were randomly assigned to receive five doses (500 mg on day 1, plus 250 mg/day on days 2-5) of azithromycin; 54 patients with acute bronchitis and four with pneumonia were assigned 30 doses (625 mg every eight hours for ten days) of amoxicillin/clavulanic acid (CA). The two regimens were equally effective, with clinical improvement or cure in 92% and 87% of patients respectively, bacteriological cure in 89% and 86%, with 91% and 89% of pathogens eliminated. Minor side effects occurred in 6% and 12% of patients in the two groups, respectively. No major abnormalities in laboratory safety parameters were seen in either group.

Acute Disease↗
PubMed1991

Chromoblastomycosis with malignant transformation and cutaneous-synovial secondary localization. The potential therapeutic role of itraconazole.

A case of neoplastic transformation of lesions of chromoblastomycosis is reported in a 67-year-old farmer from French Guyana. An interesting aspect of this case was the appearance of new cutaneous lesions of chromoblastomycosis, in a different site from the original lesion, and the presence of an infected synovial cyst. The potential therapeutic role of itraconazole is discussed.

Aged↗
PubMed1991

HIV-associated non-Hodgkin's lymphomas: clinical characteristics and outcome. The experience of the French Registry of HIV-associated tumors.

From 1/87 to 12/89, the French Registry of HIV-associated tumors recorded 131 cases of intermediate- and high-grade non-Hodgkin's lymphomas (NHL). There were 47 small non-cleaved Burkitt-type lymphomas (SNCL), 32 immunoblastic lymphomas (IL) and 52 diffuse large-cell or predominantly large-cell lymphomas (LCL). There were differences in the clinical patterns of the histological subtypes. Isolated extranodal presentation was less frequent in SNCL (2/47) than in IL (13/32) and LCL (17/49) (p less than 0.0001). In the latter two groups, the central nervous system was the principal site of extranodal involvement (16/30), 87% of SNCL, patients had no previous manifestations of AIDS whereas 40% of IL and LCL patients presented full-blown AIDS (p less than 0.01). At the time of NHL diagnosis, the median blood CD4 lymphocyte count was higher in SNCL (266/microL) than in LCL (125/microL, p less than 0.05) and IL (80/microL, p less than 0.01), 69% of stages I/II patients, 31% of stages III/IV, and 33% of stage ie patients achieved complete remission (CR), p less than 0.05. Overall median survival time was 5 months. There was no statistical difference in CR and survival rates among histological types. The two-year actuarial survival rate was 25% (median 8 months) for initially asymptomatic patients or those with persistent generalized lymphadenopathy (PGL) and 9% (median 3 months) for those previously with AIDS-related complex (ARC) and AIDS patients (p less than 0.001). Response to treatment was the other predictor factor. The two-year survival rate was 42% (median 16 months) for patients who achieved CR, and 5% (median 3 months) for those who did not.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Activation of peripheral CD8+ T lymphocytes via CD28 plus CD2: evidence for IL-2 gene transcription mediated by CD28 activation.

It is well established that peripheral CD8+ and CD4+ T cells display different requirements for in vitro activation by mitogenic mAb. Most CD4+ T cells can be activated by anti-CD3 or mitogenic combinations of anti-CD2. In contrast, CD8+ T cells display minimal responses to CD3 activation, and no proliferation is observed via CD2 activation. Purified peripheral blood CD8+ T cells, stringently depleted of APC, have been studied for their capacity to respond to mAb directed against CD3, CD2 and CD28, used alone or in combination. It is demonstrated that proliferation can be induced by co-stimulation of CD2 and CD28. This does not require autologous APC. CD8+ T cells can also be activated by the combination of anti-CD3 plus anti-CD28 in the presence of APC, but only minimal cell proliferation is obtained in the absence of APC. The response via CD2 plus CD28 is IL-2-dependent, as demonstrated by the ability of mAb against the IL-2 receptor to block proliferation, and is almost completely inhibited by cyclosporine A (CsA). These results suggest that the signal generated by stimulation of CD28 in combination with CD2 differs from that seen with CD28 activation combined with either PMA or CD3. Induction of IL-2 gene activation in CD8+, CD28+ peripheral T cells may therefore require additional "second signals", which are not necessary for activation of CD4+ cells. One such signal might be the interaction between CD28 and its natural ligand.

Antibodies, Monoclonal↗
PubMed1990

Identification of the anti-CD3-unresponsive subpopulation of CD4+, CD45RA+ peripheral T lymphocytes.

The majority of peripheral CD4+ T lymphocytes proliferate in vitro in response to anti-CD3 in presence of autologous APC. The present study describes a subpopulation of CD4+ T cells that cannot be activated and progress into cell cycle by stimulation with anti-CD3 plus APC or with mitogenic combinations of anti-CD2. The in vitro responses of these anti-CD3-unresponsive CD4+ T cells were investigated with a panel of mAb to CD2, CD3, and CD28, and found to be similar to those previously observed for mature thymocytes: only the combination of anti-CD2 plus anti-CD28 produced cell proliferation. Anti-CD3-unresponsive T cells were CD45RA+, but represented only 14 to 22% of the CD4+, CD45RA+ T cell population. Activation with anti-CD2 plus anti-CD28 mAb resulted in major changes in the cell surface phenotype and functional properties: a loss of CD45RA+ occurred and an increased expression of CD45RO, CD29, and CD58 (LFA3), as well as a gain in responsiveness to anti-CD3 and anti-CD2. This change in CD45 phenotype from CD45RA to CD45RO occurs in both the anti-CD3-responsive and in the anti-CD3-unresponsive subsets of the CD45RA+, CD4+ cells after cell proliferation. The anti-CD3-unresponsive subset may represent a pool of not yet fully differentiated peripheral T cells. The acquisition of anti-CD3 responsiveness could occur as a consequence of Ag priming or by an Ag-independent mechanism. Involvement of the CD28 Ag in this process is suggested from the present study.

Antibodies, Monoclonal↗