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Biomedical subjects

M Buisson

Publications and source records attributed to M Buisson.

At least 19 recordsLinked to original sources
PubMed1998

Different distribution of H1-H2 Epstein-Barr virus variant in oropharyngeal virus and in biopsies of Hodgkin's disease and in nasopharyngeal carcinoma from Algeria.

In a previous study of Epstein-Barr virus (EBV) strains in North African nasopharyngeal carcinoma (N PC) biopsies, we have found that the viral strain present was of A/F/W'-I'/Xhol kept/H1-H2 type, while the strain associated with Chinese NPC was the A/"f"/W'I'/Xhol lost/H type. Using the restriction fragment length polymorphism (RFLP) and PCR-RFLP methods, the present study analyzed the H1-H2 variant in different clinical samples from Algeria, including the saliva of healthy EBV-positive individuals and patients with NPC or Hodgkin's disease (HD), as well as HD biopsies and lymphoblastoid cell lines (LCLs) established from the oropharyngeal virus-infected cells. Our results demonstrate that, in contrast to the H1-H2 variant found in NPC biopsies, the H genotype was dominant in HD biopsies. Moreover, H genotype was also dominant in the oropharynx of healthy EBV-positive individuals, of patients with NPC and with HD. Our results clearly indicate that in North Africa the EBV strain present of NPC biopsies is different from that shed in the oropharynx. This may suggest a specific distribution of the H1-H2 variant in the NPC epithelial tumor, whereas the H genotype is dominant in HD biopsies and in the oropharynx. The specific association of both viral strains with these 2 distinct diseases in North Africa may reflect a difference in tumorigenicity.

Algeria↗
PubMed1998

Does hepatitis C virus co-infection accelerate clinical and immunological evolution of HIV-infected patients?

OBJECTIVE: To study the influence of hepatitis C virus (HCV) co-infection on clinical and immunological evolution of HIV-infected patients. DESIGN: A longitudinal study of HIV-infected individuals with or without HCV infection, identified at the Infectious Diseases Department of Dijon University Hospital and enrolled in a historical cohort, was performed. METHODS: One hundred and nineteen HIV-infected people co-infected with HCV and 119 matched individuals infected with HIV alone were included in the cohort (median participation time 3 years; range, 2 months to 11.5 years). Clinical progression was defined as one or more of the following: a 30% decrease in the Karnofsky index; a 20% loss of body weight; an AIDS-defining illness (for non-AIDS patients); death (except by accident, suicide or overdose). Immunological progression was defined as a 50% decrease in the initial CD4 T-cell count (for patients with an initial count > 100 x 10(6) cells/l). Effects of HCV co-infection were evaluated using Kaplan-Meier survival analysis and significance was tested using univariate (log-rank and Peto's tests) and multivariate methods (Cox's model). RESULTS: In univariate analysis, immunological progression was not statistically different between the HCV-positive group and the HCV-negative group, whereas clinical progression was significantly faster in HCV-positive patients (P < 0.005, log-rank test). In a multivariate Cox model, clinical progression remained significantly associated with infection by HCV [hazard ratio (HR), 1.64; 95% confidence interval (CI), 1.06-2.55; P < 0.05]. Stratified multivariable analysis retained HCV as a significant prognostic factor of clinical progression (HR, 10.9; 95% CI, 1.09-109.3; P < 0.05) and immunological progression (HR, 2.31; 95% CI, 1.16-4.62; P < 0.02) for patients with an initial CD4 count above 600 x 10(6) cells/l. CONCLUSIONS: Clinical progression is more rapid in HIV-HCV co-infected patients than in HIV-seropositive patients are not infected by HCV. The prognostic value of HCV infection for both clinical and immunological progression is significant at early stages of HIV infection. These findings may argue for active management of hepatitis C infection in co-infected individuals, especially for asymptomatic patients whose CD4 count is above 600 x 10(6) cells/l, to predict and prevent accelerated progression of HCV and HIV diseases.

Adult↗
PubMed1998

Experimental efficacy of combined ceftriaxone and amoxycillin on penicillin-resistant and broad-spectrum cephalosporin-resistant Streptococcus pneumoniae infection.

The activity of amoxycillin and ceftriaxone, alone and in combination, was tested against four strains of penicillin-resistant pneumococci in vitro and in an animal model. Three of the strains were also resistant to third-generation cephalosporins. Fractional inhibitory concentration indexes for combined amoxycillin and ceftriaxone were measured by the Etest method and were considered additive (1.2; 1.1; 1.3 and 1.3 for the four strains). Twenty-four hour time-kill curves for two strains showed that the combination was additive or synergic for concentrations up to the MIC of the single drugs. The efficacy of these antibiotics alone and in various combinations against strains 16089 and 11724 were investigated in vivo using prolonged (48 h) experimental fibrin clot infection in rabbits. The bacterial reductions (delta log10 cfu/g) obtained for all the antibiotic combinations tested were significantly higher than those of the single drug regimens. The in-vivo efficacy of amoxycillin was significantly correlated with the time for which its concentration was above the MIC and that of ceftriaxone was correlated with its maximal concentration. From these findings, we concluded that, at concentrations easily achievable in humans, the combination of amoxycillin and ceftriaxone was strongly synergic against infection due to penicillin- and cephalosporin-resistant pneumococci.

Amoxicillin↗
PubMed1997

Non-Hodgkin's lymphoma of the heart in patients infected with human immunodeficiency virus.

A case of HIV-associated cardiac non-Hodgkin's lymphoma (NHL) is described, and the epidemiologic and clinicopathologic features of 21 cases previously reported in the literature are analyzed. All patients were homosexual males, and the cardiac NHL was the first acquired immune deficiency syndrome-defining condition in the majority. Patients were referred with nonspecific clinical findings including dyspnea and tachycardia, but rapid progression of cardiac dysfunction was frequent after symptoms appeared. Echocardiography constitutes the most useful noninvasive procedure in the diagnosis of cardiac NHL. Most of the patients had disseminated diseased at initial presentation; pathologically, the lymphomas were of B lymphocyte origin and of high-grade subtypes. Prognosis of HIV-associated cardiac NHL is generally poor, although clinical remission has been observed with combination chemotherapy. Cardiac lymphomas in HIV-associated patients are typically high-grade and often disseminate early. Although the prognosis is poor, patients in whom dissemination has not occurred could have longer survival under systemic chemotherapy.

Adult↗
PubMed1997

In-vivo activity and tolerance of conventional formulation versus fat emulsion formulation of amphotericin B in experimental disseminated candidiasis in neutropenic rabbits.

Amphotericin B can cause significant toxicity but this can be reduced by direct dilution into a fat emulsion (Intralipid). To investigate the potential use of amphotericin B diluted in Intralipid, a study was made of its activity in the treatment of subacute disseminated candidiasis in persistently granulocytopenic rabbits, compared with the same dose of amphotericin B diluted in dextrose. Amphotericin-B-fat emulsion was at least as effective as amphotericin-B-dextrose. Amphotericin-B-fat emulsion was significantly more effective than amphotericin-B-dextrose therapy in reducing candida colony counts in both kidney and liver tissues (P < 0.05). Furthermore, amphotericin-B-fat emulsion was found less toxic on the renal function than conventional amphotericin B (P < 0.05). From these experimental results, we conclude that amphotericin-B-fat emulsion (Intralipid) was at least as effective and less toxic than conventional amphotericin B.

Amphotericin B↗
PubMed1996

Genotyping human and bovine isolates of Cryptosporidium parvum by polymerase chain reaction-restriction fragment length polymorphism analysis of a repetitive DNA sequence.

In order to define transmission routes of cryptosporidiosis and develop markers that distinguish Cryptosporidium parvum isolates, we have identified 2 polymorphic restriction enzyme sites in a C. parvum repetitive DNA sequence. The target sequence was amplified by polymerase chain reaction from 100 to 500 oocysts and the amplified product was subjected to restriction enzyme digestion. Typing of 23 isolates showed that 10/10 calf isolates had the same profile. In contrast, 2 patterns were observed among human isolates: 7/13 displayed the calf profile, and 6/13 presented another pattern. The PCR-RFLP assay described here is a sensitive tool to distinguish C. parvum isolates.

Animals↗
PubMed1996

[Pneumocystis carinii pneumonia in AIDS: retrospective analysis of 80 documented cases (1985-1993)].

Eighty initial episodes of HIV-associated Pneumocystis carinii pneumonia (PCP) diagnosed at Bordeaux hospital between 1985 and 1993 are reported (57 were men and 23 women). PCP revealed HIV infection in 29 patients (36%). Others cases were patients with poor medical follow up (10%), with a CD4+ lymphocyte count above 200/mm3 at last follow-up (9%), non compliant with PCP prophylaxis (9%), or using aerolized pentamidine (AP+) (20%). The main clinical symptoms were fever (90%), dyspnea (68%), non productive (63%) and productive (17%) cough. Radiographic infiltrates were purely interstitial (59%), acinar and interstitial (25%), purely acinar (5%) and absent (11%). Thirty-eight percent of AP+ had upper lobe preferential involvement and 13% a pleural effusion. In all cases, Pneumocystis carinii was detected in bronchoalveolar lavage. Extrapulmonary localizations of pneumocystosis were noticed (eye, liver, spleen, ascitis) in two AP+. Mean CD4+ count was 54/mm3 in patients not having received aerolized pentamidine (AP-) and 22/mm3 in AP+. P24 antigenemia was positive in 53% (AP-) and 88% (AP+). PaO2 LDH and albuminemia were similar in both groups. Antimicrobial therapy (Cotrimoxazole in 91% of the cases) was combined with corticosteroids in 45% and mechanic ventilation in 19%. After 30 days of follow-up, 17 deaths were observed (21%) and 14 attributed to PCP: mortality was worse in AP+ (31%) than in AP- (19%). The main conclusions of our study are the followings: HIV related PCP is still in 1995 frequent and severe; atypical features should not rule out diagnosis; preventive measures are neither sufficient nor efficient. PCP remains in 1995 a priority in HIV related public health and therapeutical research.

AIDS-Related Opportunistic Infections↗
PubMed1996

Vertebral osteomyelitis due to Capnocytophaga species in immunocompetent patients: report of two cases and review.

Vertebral osteomyelitis caused by Capnocytophaga species was diagnosed in two adults. One of these infections was due to C. ochracea and the other was due to C. sputigena. Both patients were immunocompetent and presented with concomitant periodontitis and gingivitis. The infections were eradicated by means of prolonged antibiotic therapy, combined in one case with surgical treatment. Capnocytophaga species should be considered a potential cause of vertebral osteomyelitis in immunocompetent patients, especially in the presence of oral pathology.

Aged↗
PubMed1996

In-vivo activity and pharmacodynamics of cefotaxime in combination with vancomycin in fibrin clots infected with highly penicillin-resistant Streptococcus pneumoniae.

We studied the antipneumococcal efficacy of cefotaxime and vancomycin alone and a combination of cefotaxime with various dosages of vancomycin in the treatment of prolonged (48 h) experimental fibrin clot infections in rabbits. A clinical pneumococcal strain for which MICs were 2, 0.5 and 0.5 mg/L of penicillin, cefotaxime and vancomycin respectively, was used in this study. Cefotaxime was given iv at a fixed dose of 50 mg/kg and vancomycin iv at 1, 2.5, 5, 10 or 20 mg/kg. Maximal concentrations in clots were (mean +/- S.D.): 2.1 +/- 0.9, 1.1 +/- 0.4, 1.9 +/- 1, 2.3 +/- 1.5, 3.6 +/- 0.4 and 4 +/- 0.3 mg/g, respectively. The mean half-lives of elimination from clots were 2.2 h for cefotaxime and 7 h for vancomycin. We observed the highest bacterial reductions for the highest doses of vancomycin with or without cefotaxime. The combination of intermediate doses of vancomycin with cefotaxime led to higher antibacterial effects than either monotherapy. The low dose of vancomycin gave no significant additional effect compared with cefotaxime alone. The times of regrowth were similar for cefotaxime and cefotaxime-vancomycin 1, and also for vancomycin 10 and vancomycin 20 with or without cefotaxime but were significantly delayed for the combination cefotaxime-vancomycin 2.5 and cefotaxime-vancomycin 5 as compared with vancomycin 2.5 and vancomycin 5. By using a multivariate analysis, we demonstrated that the most important parameters were Cmax (r = 0.43) and AUC (r = 0.58) for cefotaxime alone and Cmax (r = 0.70) for vancomycin alone; none of the tested parameters was found to be significantly correlated with the efficacy of the combinations of cefotaxime and vancomycin. From these findings, and under the experimental conditions used (i.e., relatively low concentrations of cefotaxime), we demonstrated that the in-vivo antibacterial efficacy of the combination of cefotaxime and vancomycin was higher than each monotherapy when the local concentrations of vancomycin were at least 1.9 mg/L.

Analysis of Variance↗
PubMed1996

In vivo activity and pharmacodynamics of amoxicillin in combination with fosfomycin in fibrin clots infected with highly penicillin-resistant Streptococcus pneumoniae.

Using a clinical pneumococcal strain for which MICs were 4, 2, and 32 mg/liter for penicillin, amoxicillin, and fosfomycin, respectively, we studied the efficacies of these antibiotics alone and their combinations in the treatment of prolonged (48-h) experimental fibrin clot infection in rabbits. Treatments were as follows: amoxicillin IV at 20 mg/kg of body weight in one dose (Amo20), 50 mg/kg in one dose (Amo50), or two doses 6 h apart (Amo20 x 2 and Amo50 x 2); fosfomycin IV at a fixed dose of 50 mg/kg in one dose (Fos50) or two divided doses 6 h apart (Fos50 x 2); or the combinations of amoxicillin and fosfomycin with the same schedules. Maximum concentrations in clots were 2.03 +/- 1.02 and 2.13 +/- 0.33 mg/liter for Amo20 regimens, 3.7 +/- 1.9 and 4 +/- 1.3 mg/liter for Amo50 regimens, and 24 +/- 7 and 40 +/- 8 mg/liter for fosfomycin regimens, respectively. The mean half-lives of elimination from clots were between 2 and 3 h for amoxicillin regimens and between 5 and 7 h for fosfomycin. We observed the highest bacterial reductions (log10 CFU/gram) for Amo50 in two divided doses with or without fosfomycin. A significantly higher bacterial reduction than that with each monotherapy was observed when Amo20 was combined with fosfomycin in either one dose or two doses 6 h apart (0.16 +/- 0.8 and 1.64 +/- 1.6 log10 CFU/g for Amo20 in one and two doses, respectively, and 0.93 +/- 0.81 and 0.61 +/- 0.56 log10 CFU/g for fosfomycin in one and two doses, respectively, versus 3.46 +/- 1.26 and 3.16 +/- 1.31 log10 CFU/g for Amo20 plus fosfomycin in one and two doses, respectively [P < 0.001]). A time-dependent effect was observed with amoxicillin regimens. The time of regrowth was significantly delayed when amoxicillin was combined with fosfomycin. By using a multivariate analysis, we demonstrated that the most important parameter correlated to efficacy of the combination amoxicillin-fosfomycin was the length of the period during which the concentration of amoxicillin remained above the MIC. We demonstrated that the in vivo efficacy of the combination of amoxicillin and fosfomycin gave higher antibacterial effect than each monotherapy.

Amoxicillin↗
PubMed1995

T-cell death by apoptosis in vertically human immunodeficiency virus-infected children coincides with expansion of CD8+/interleukin-2 receptor-/HLA-DR+ T cells: sign of a possible role for herpes viruses as cofactors?

One mechanism proposed to play a role in T-cell depletion in human immunodeficiency virus (HIV) infection is apoptosis (activation-induced cell death). We assessed whether apoptosis is related to activation of T cells in vivo and its possible triggers. DNA was extracted from peripheral blood mononuclear cells (PBMC) taken from 16 vertically HIV-infected children and 9 HIV-negative children born to HIV-positive mothers (controls) and tested by agarose gel electrophoresis for the presence of DNA fragments specific for apoptosis. Signs of apoptosis were found on in vitro culture of PBMC from 12 of 16 HIV-infected children, but not in PBMC from the nine controls. Eleven of the 12 HIV-infected children with apoptosis showed an elevated (> 15%) proportion of CD3+/HLA-DR+ cells. This was due to an increased proportion of CD8+/HLA-DR+ cells, as shown in 7 of 7 further tested patients. In none of the probands an increased (> 5%) proportion of IL-2 receptor expressing CD3+ cells was found. T cells undergoing apoptosis were preferentially of the CD8+ phenotype. Expansion of circulating CD8+/interleukin-2 receptor (IL-2R)-/HLA-DR+ T cells is known to occur during active infection with herpes viruses. To investigate the possible role of herpes viral coinfections for apoptosis in HIV infection, we focused on Epstein-Barr virus (EBV) as an example for a herpes virus usually acquired during childhood. In 10 of 12 patients with apoptosis, we found increased levels of EBV genome in PBMC and/or tissues, indicating active EBV replication. By contrast, no increased burden of EBV was found in the four HIV-infected patients without apoptosis or in the controls. Our data indicate that in children the occurrence of apoptosis in HIV infection is closely related to activation of CD8+ T cells. Furthermore, primoinfection with or reactivation of herpes viruses, such as EBV, may substantially contribute to such T-cell activation and the ensuing apoptosis. Additional studies are warranted to evaluate the contribution of herpes virus-triggered apoptosis to the T-cell loss leading to the acquired immunodeficiency syndrome.

Apoptosis↗
PubMed1995

[Neurologic manifestations of Lyme disease. Apropos of 25 cases].

We studied retrospectively the cases of neurological forms of Lyme disease observed in two internal and two neurological departments from 1986 till 1993. Twenty five cases have been collected among 15 men and ten women whose mean age was 61 years. Tick bites were previously noticed in 11 cases. Erythema chronicum migrans (ECM) was mentioned in 16 cases mostly on lower limbs. The mean time between ECM and the onset of neurological symptoms was less than 1 month in 11 cases, 2 months in three cases, and 6 months in two cases. Neurological abnormalities were often associated in the same patient. Hyperalgic radiculitis (n = 16), mainly noticed in the ECM territory (n = 10) was only sensitive in six cases and associated with motor deficit in ten. Atypical polyradiculoneuritis was achieved in six cases. Clinical (n = 5) or biological (n = 22) meningitis could occur: CSF was clear with pleiocytosis (132 per mm3), mainly lymphocytic, and hyperproteinorachia (1.2 g/l) with normoglycorachia. An increase of the CSF immunoglobulins G with oligoclonal fragmentation was noticed in 11 cases. Cranial neuropathy was frequent: VII (n = 8), VI (n = 2), III, IV, VIII (n = 1). Encephalitis (with white matter demyelination) resolved partially in two cases. Diagnosis was always confirmed by Borrelia burgdorferi serology (indirect immunofluorescence) with a significant increase of the antibodies titer (n = 17) or a CSF titer > 1/4 (n = 11). Syphilitic serology was always negative. All patients were treated with parenteral beta lactamins and four with corticosteroids. Outcome was favorable in 20 patients with incomplete resolution of neurological symptoms in two patients.

Adult↗
PubMed1995

[Effect of primary prevention of Pneumocystis carinii pneumonia on the inaugural clinical and biological presentation of AIDS: 624 cases (Aquitaine Cohort, 1985-1994)].

In a cohort of HIV-infected patients, this study compares the clinical and immunological features at the time of AIDS diagnosis of patients who either received primary Pneumocystis carinii prophylaxis (P+; n = 335) or who did not (P-; n = 289). Frequency of P carinii pneumonia was lower in P+ than in P- patients (14.9% vs 26.0%; p < 0.001). Conversely, toxoplasmic encephalitis, esophageal candidiasis, cytomegalovirus disease and M avium complex disease were more frequent in P+ patients. CD4+ count (median/mm3) at the time of AIDS diagnosis was lower in P+ than in P- patients: 22 vs 97 (p < 0.001); this suggests that early intervention delays the onset of AIDS for about one year. While searching for new prevention strategies against other opportunistic infections, efforts should be expanded to improve prophylaxis of P carinii pneumonia which remains in France the most frequent first AIDS-related illness.

AIDS-Related Opportunistic Infections↗
PubMed1995

[Invasive pulmonary aspergillosis in neutropenic patients. Analysis of a series of 36 cases: contribution of thoracic scanners and itraconazole].

In neutropenic patients, one way of improving invasive pulmonary aspergillosis (IPA) prognosis is an earlier initiation of the antifungal treatment. We report our experience with 36 cases of IPA in 35 patients with haematological malignancies. When aspergillosis was diagnosed, all but 2 patients were neutropenic (PMN < 500; median duration = 20 days). The most frequent clinical signs were cough (100%), chest pain (78%) and haemoptysis (58%). Before the diagnosis of IPA, Aspergillus antibody test was positive in 60% of cases. A thoracic CT-scan was performed in 23 patients and demonstrated highly suggestive images in 22 cases (96%) with presence of CT halo sign (n = 13) or CT air-crescent sign (n = 9). Moreover, Aspergillus antigen test was positive in 13 of 28 tested patients. IPA diagnosis was determined to be definite in 23 cases and probable or possible in 13 cases. Thirty-five patients were treated: in 3 cases with amphotericin B (2 failures) and in 32 cases with itraconazole (7 failures and 25 successes or improvements). In 7 cases (including 5 emergencies) surgical resection was successfully combined with the medical treatment. In neutropenic patients with fever, we consider that thoracic CT-scan and repeated biological tests (Aspergillus antibody and antigen tests) can be used to establish the diagnosis of aspergillosis. Early treatment with itraconazole and surgical resection appears to improve prognosis.

Adult↗
PubMed1994

[New macrolides].

The macrolides are still widely used in general practice and the new 14- or 15 membered-ring compounds-roxithromycin, clarithromycin, dirithromycin, azithromycin -may offer a new development. Their antibacterial activity is similar to erythromycin but azithromycin is more active against Gram negative strams. Roxythromycin exhibits high serum concentrations; azithromycin and dirithromycin present low serum concentrations but prolonged half-lives allowing a reduction of the duration of treatment particularly for pharyngitis (azithromycin). Macrolides are less useful for otitis and sinusitis treatment since their activity against H. influenzae and S. pneumoniae are weak. The activity against atypical bacteria justify their choice as first line treatment for benign atypical pneumonia of healthy young adults and for sexually transmitted diseases. In AIDS, these compounds are indicated in mycobacteriosis (clarithromycin), bacillary angiomatosis and excavated pneumonia due to Rhodococcus equi. Clinical tolerance is very good, particularly the gastro-intestinal one. The reported drug interactions are those of this class of antibiotics.

Anti-Bacterial Agents↗