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Biomedical subjects

C Michelet

Publications and source records attributed to C Michelet.

At least 19 recordsLinked to original sources

[Renal failure during treatment with Ambisome].

BACKGROUND: Although renal function is generally unaffected by liposome formulations of amphotericin B-deoxycholate, there is nevertheless a risk. CASE REPORTS: Two patients immunodepressed patients treated for candidosis involving the mouth and esophagus unresponsive to local care and flucanazol developed renal failure when given the liposome formulation of amphotericin B-deoxycholate (AmBisome). In one with normal renal function prior to treatment, moderate impairment was observed after initiating AmBisome. In the second patient, impaired renal function worsened after initiating treatment with amphotericin B-deoxycholate then progressed to very severe renal failure after switching to AmBisome. CONCLUSION: The indication for AmBisome (amphotericin B-deoxycholate treatment in patients with active renal impairment) must not overshadow the risk of worsening renal function under treatment.

Adult↗

Persistent alterations in T-cell repertoire, cytokine and chemokine receptor gene expression after 1 year of highly active antiretroviral therapy.

OBJECTIVES: To examine T-cell repertoire modifications, the evolution of T-helper (TH)1/TH2 cytokine imbalance and modifications in chemokine receptor expression when the viral load is decreased by 2-3 log10 copies/ml under highly active antiretroviral therapy (HAART). DESIGN: Sixteen patients previously treated with zidovudine and lamivudine, with CD4 cells below 300 x 10(6)/l and viraemia above 30000 copies/ml were treated by saquinavir and ritonavir together with both reverse transcriptase (RT) inhibitors (ANRS 069 trial). T-cell repertoire, chemokine receptor and lymphokine expression were studied from peripheral blood mononuclear cells sampled at weeks 0, 24 and 48. METHODS: T-cell repertoire study was carried out using the Immunoscope method. Interleukin (IL)-12 receptor beta2, CC-chemokine receptor (CCR)-3, CXC-chemokine receptor-4 and CCR-5 expression in CD4+ cells was measured by kinetic quantitative PCR and IL-2, IL-4, IL-10, IL-13, interferon (IFN)-gamma were measured using a quantitative RT-PCR assay with homologous internal standards. RESULTS: Repertoire alterations were more frequent in CD4- than in CD4+ cells and persisted despite undetectable viraemia. Increased CCR-3 expression and spontaneous IFN-gamma as well as mitogenic induced IL-13 were observed at baseline and decreased slightly under HAART. CONCLUSION: The CD8+ cell repertoire alterations were profound, whereas the CD4+ cell alterations were moderate and both persisted unchanged under HAART. The TH1/TH2 imbalance was more related to TH2 over-expression than to TH1 deficiency and persisted for at least 1 year under HAART.

Adult↗

Trial of dexamethasone treatment for severe bacterial meningitis in adults. Adult Meningitis Steroid Group.

OBJECTIVE: To evaluate the clinical benefit of early adjunctive dexamethasone therapy for severe bacterial meningitis in adults. DESIGN: Multicenter, double-blind, randomized trial initiated in emergency or intensive care units in France and Switzerland. Within 3 h after initiation of an aminopenicillin therapy, patients received dexamethasone (10 mg q.i.d.) or placebo for 3 days. The primary end-point was the rate of patients cured without any neurologic sequelae on day 30. RESULTS: Sixty patients were enrolled, predominantly with a severe form since 85% required ICU stay and 43% mechanical ventilation. Streptococcus pneumoniae accounted for 31 cases and Neisseria meningitidis for 18 cases. The study had to be stopped prematurely because of a new national recommendation of experts to use third generation cephalosporin and vancomycin as a result of the increasing rate of penicillin-resistant S. pneumoniae in France. After the third sequential analysis by the triangular statistical test, the difference of rate of cured patients without any neurologic sequelae was not statistically significant (p = 0.0711) between the dexamethasone group (74.2%; n = 31) and the placebo group (51.7%; n = 29). Furthermore, the former group was younger and less sick at inclusion. CONCLUSION: Bacterial meningitis is still a severe disease in adults, since the overall observed rate of death or severe neurologic sequelae was 26.7%. The reported data are inconclusive regarding a systematic use of dexamethasone as an adjunctive therapy for bacterial meningitis in adults. Moreover this treatment impairs antibiotic penetration into the cerebrospinal fluid (CSF) that can lead to therapeutic failure, particularly in areas with high or increasing rates of penicillin-resistant S. pneumoniae.

Adult↗

Safety and efficacy of ritonavir and saquinavir in combination with zidovudine and lamivudine.

BACKGROUND: Ritonavir is a potent inhibitor of cytochrome P4503A4 that strongly increases saquinavir bioavailability. In this study we assessed the safety and antiretroviral efficacy of the combination of these two compounds in patients pretreated and receiving continued treatment with zidovudine and lamivudine who were protease inhibitor naive and who had a CD4 cell counts below 200/mm3. METHODS: In this 48-week pilot study, all patients received 600 mg ritonavir and 400 mg saquinavir twice daily. Administration of zidovudine and lamivudine was continued without a change in previous doses. Viral load, CD4 cell count, and the emergence of resistance to the two protease inhibitors were evaluated repeatedly up to week 48. RESULTS: Sixteen patients were included in the study. Previous nucleoside analog treatment duration was 48+/-22 months (mean +/- SD). Two patients quit taking both protease inhibitors within 2 weeks. The ritonavir dose had to be reduced in 10 other patients because of side effects. Between inclusion and week 48, plasma viremia varied from 4.87+/-0.43 to 3.00+/-1.29 log10 copies/mL and CD4 cell counts ranged from 98+/-61 to 250+/-139/mm3. Ten patients (63%) had viral loads below 200 copies/mL and 7 (44%) had viral loads below 50 copies/mL. A single key mutation that conferred ritonavir resistance I84V and V82A/V developed in two patients. A mutation at codon 54 developed in another patient. These mutations were associated with repeated cessations of antiretroviral treatment. No lipodystrophy was observed. CONCLUSION: Ritonavir and saquinavir in combination are quite well tolerated and induce a high and sustained antiretroviral efficacy. A four-drug combination that includes these two protease inhibitors should be considered as a first line of treatment in patients with low CD4 cell counts.

Acquired Immunodeficiency Syndrome↗

Comparative efficacies of antibiotics in a rat model of meningoencephalitis due to Listeria monocytogenes.

The antibacterial activities of amoxicillin-gentamicin, trovafloxacin, trimethoprim-sulfamethoxazole (TMP-SMX) and the combination of trovafloxacin with TMP-SMX were compared in a model of meningoencephalitis due to Listeria monocytogenes in infant rats. At 22 h after intracisternal infection, the cerebrospinal fluid was cultured to document meningitis, and the treatment was started. Treatment was instituted for 48 h, and efficacy was evaluated 24 h after administration of the last dose. All tested treatment regimens exhibited significant activities in brain, liver, and blood compared to infected rats receiving saline (P < 0.001). In the brain, amoxicillin plus gentamicin was more active than all of the other regimens, and trovafloxacin was more active than TMP-SMX (bacterial titers of 4.1 +/- 0.5 log10 CFU/ml for amoxicillin-gentamicin, 5.0 +/- 0.4 log10 CFU/ml for trovafloxacin, and 5.8 +/- 0.5 log10 CFU/ml for TMP-SMX; P < 0.05). In liver, amoxicillin-gentamicin and trovafloxacin were similarly active (2.8 +/- 0.8 and 2.7 +/- 0.8 log10 CFU/ml, respectively) but more active than TMP-SMX (4.4 +/- 0. 6 log10 CFU/ml; P < 0.05). The combination of trovafloxacin with TMP-SMX did not alter the antibacterial effect in the brain, but it did reduce the effect of trovafloxacin in the liver. Amoxicillin-gentamicin was the most active therapy in this study, but the activity of trovafloxacin suggests that further studies with this drug for the treatment of Listeria infections may be warranted.

Animals↗

Amplification of the six major human herpesviruses from cerebrospinal fluid by a single PCR.

We used a novel type of primer system, a system that uses stair primers, in which the primer sequences are based on consensus sequences in the DNA polymerase gene of herpesvirus to detect herpesviruses by PCR. A single PCR in a single tube detected the six major herpesviruses that infect the central nervous system: herpes simplex virus type 1 (HSV-1), and type 2 (HSV-2), cytomegalovirus (CMV), Epstein-Barr virus (EBV), varicella-zoster virus (VZV), and human herpesvirus 6 (HHV-6). We used the technique to analyze 142 cerebrospinal fluid (CSF) samples that had been stored at -80 degrees C and compared the results with those obtained previously for the same samples by standard, targeted PCR. Four hundred one targeted PCR tests had been run with the 142 samples to detect HSV-1, HSV-2, CMV, and VZV; screening for EBV and HHV-6 was not prescribed when the samples were initially taken. Eighteen CSF samples tested positive by classic targeted PCR. The herpesvirus consensus PCR detected herpesviruses in 37 samples, including 3 samples with coinfections and 17 viral isolates which were not targeted. Two samples identified as infected by the targeted PCR tested negative by the consensus PCR, and eight samples that tested positive by the consensus PCR were negative by the targeted PCR. One hundred three samples scored negative by both the targeted and the consensus PCRs. This preliminary study demonstrates the value of testing for six different herpesviruses simultaneously by a sensitive and straightforward technique rather than screening only for those viruses that are causing infections as suggested by clinical signs.

Consensus Sequence↗

Efficacy and safety of stavudine and didanosine combination therapy in antiretroviral-experienced patients.

OBJECTIVES: To assess the efficacy, tolerance, and safety of combination antiretroviral therapy with didanosine and stavudine in HIV-infected patients with CD4+ cell counts > 100 x 10(6)/l and HIV plasma RNA > 10(4) copies/ml previously treated with other antiretroviral agents for at least 3 months. DESIGN: In this open, multicentre, non-randomized, Phase II pilot study, adult patients were administered didanosine (200 mg twice daily) plus stavudine (40 mg twice daily) for 6 months. Patients for whom the first regimen had led to undetectable HIV RNA levels were offered a second 6-month course of treatment; those who had achieved insufficient immunological and virological gains in the first 6 months were given a new combination. METHODS: Primary evaluation of efficacy was based on viral load measured by branched DNA second-generation testing (lower limit of detection, 500 copies/ml) and CD4+ cell counts; secondary evaluations included AIDS-defining events and clinical side-effects. RESULTS: Sixty-five patients with median prior antiretroviral therapy of 24 months (65 with zidovudine, 29 with zalcitabine) were included in the study. At baseline, median CD4+ cell count was 198 x 10(6)/l and median plasma HIV RNA was 80000 copies/ml (4.9 log10 copies/ml). In this heavily pretreated population, an increase in the mean CD4+ cell count was observed (+70 x 10(6)/l at 24 weeks). In addition, rapid and prolonged antiviral activity was seen, with a mean maximal decrease of 1.1 log10 copies/ml at week 4, a mean decrease of 0.89 log10 copies/ml at week 24, and a plasma RNA viraemia < 500 copies/ml achieved in 14% of patients at week 24. CONCLUSIONS: Combination therapy with stavudine and didanosine is safe and leads to a sustained antiviral effect, even in patients with prolonged prior antiretroviral exposure and low CD4+ cell counts.

Adult↗

Opportunistic infections occurring during highly active antiretroviral treatment.

OBJECTIVE: To analyse the characteristics of opportunistic infections in patients receiving highly active antiretroviral treatment (HAART). DESIGN AND METHODS: A retrospective study performed in seven hospitals, included all patients starting treatment by ritonavir or indinavir between 26 March and 31 December 1996. Patients were evaluated for the development of AIDS-defining events. Clinical evaluation, plasma HIV-1 RNA quantification, CD4 cell count were recorded at baseline and at the onset of the event. RESULTS: Four hundred and eighty-six patients were included: 44.2% had a CD4 cell count below 50 x 10(6) cells/l. Fifty clinical events were recorded in 46 patients with a mean follow-up of 6.1 months, of which 34 events (68%) were observed during the first 2 months of HAART. Eighteen of these occurred despite a reduction of viral load by at least 1.5 log10) and a 100% increase of the CD4 cell count compared with that at the onset of the event, corresponding to 11 cytomegalovirus infections, five mycobacterial infections, one case of cryptococcosis, and one case of Varicella-Zoster virus-related acute retinal necrosis. Among the 16 events observed after the second month, six occurred despite a marked biological improvement, corresponding to a recurrence in five of six patients who had stopped their maintenance therapy. Events were one cytomegalovirus infection, two mycobacterial infections, one episode of oesophageal candidiasis and one cryptococcal meningitis. CONCLUSION: In patients at high risk of developing an opportunistic infection prior to the institution of a HAART regimen, prophylaxis should not be discontinued during the first 2 months of treatment, and maintenance therapy should be carried on despite a significant increase in the CD4 cell count.

AIDS-Related Opportunistic Infections↗

The presence of cytoplasmic antineutrophil cytoplasmic antibodies (C-ANCA) in the course of subacute bacterial endocarditis with glomerular involvement, coincidence or association?

Antineutrophil cytoplasmic antibodies positivity with cytoplasmic pattern (C-ANCA) and proteinase-3 (PR-3) specificity was found in two patients with both subacute bacterial endocarditis (SBE) and glomerular involvement. Renal biopsy showed membranoproliferative glomerulonephritis in one case and focal segmental glomerulonephritis in the second case. Immunofluorescence study showed granular immune deposits in both cases evocating immune complex glomerulonephritis. Renal and biological manifestations disappeared with clinical improvement secondary to antibiotherapy. Physicians have to consider the possible occurrence of such C-PR-3 ANCA, claimed to be specific markers for Wegener's granulomatosis, in infectious diseases such as SBE. Hence we focus on the necessity of performing a renal biopsy with light microscopy and immunofluorescence studies in all patients with ANCA associated glomerular disease.

Antibodies, Antineutrophil Cytoplasmic↗

Longitudinal study of HIV-specific cytotoxic lymphocytes in HIV type 1-infected patients: relative balance between host immune response and the spread of HIV type 1 infection.

To evaluate the contribution of a specific cytotoxic response in the control of HIV infection in relation to clinical status, we performed serial analysis of anti-Env and anti-Gag cytotoxic activity in 13 infected individuals over a 6- to 10-year period, using cryopreserved peripheral blood mononuclear cells (PBMCs). Autologous EBV-transformed B cell lines infected in vitro with recombinant vaccinia viruses expressing HIV-1 env and gag genes were used as targets. Without any stimulation of the effector cells, we were able to show an anti-HIV cytotoxic activity in the PBMCs of 12 of 13 HIV-1-infected patients, consistent with chronic immune activation in HIV infection. Different patterns of HIV-specific cytotoxic activity were observed, and the extent of this cytotoxic response varied between the clinically defined groups of individuals. No direct relationship was observed with the number of CD4 and CD8 lymphocytes during the observation period. However, patients who remained asymptomatic had a more vigorous cytotoxic response than patients with clinical deterioration during the observation period, and a significant difference was observed for HIV Gag-specific CTL activity. From these data, we suggest that the HIV-specific cytotoxic response has a protective role in the course of HIV infection.

B-Lymphocytes↗

A prospective study of criteria for the diagnosis of toxoplasmic encephalitis in 186 AIDS patients. The BIOTOXO Study Group.

OBJECTIVE: To define the factors associated with diagnosis of toxoplasmic encephalitis (TE) in AIDS patients; and to establish a rational procedure for the clinician faced with a decision concerning empiric antitoxoplasma therapy. DESIGN: A 15-month prospective multicentre cohort study in France. METHODS: One hundred and eighty-six consecutive HIV-positive inpatients undergoing empiric antitoxoplasma therapy for a first episode of presumed TE were monitored. The clinician's initial estimation of the probability of response to antitoxoplasma therapy was recorded. In addition, a validation committee classified cases as TE or non-TE. RESULTS: Among the 186 patients, the following variables were significantly more frequent in TE (n = 113) than non-TE (n = 73) patients: fever (59% versus 40%). headache (55% versus 33%), seizures (22% versus 11%), suggestive lesions on the brain scan (98% versus 76%), positive Toxoplasma serology (97% versus 71%). Median CD4+ lymphocyte count was significantly higher in TE than in non-TE (27 x 10(6)/l versus 11 x 10(6)/l). The rate of TE in patients on systemic antiprotozoal prophylaxis at entry was 43% as compared with 75% in patients without previous prophylaxis. Pre-therapy estimation of response to empiric therapy was highly correlated with final diagnosis. Multivariate logistic regression analysis showed that the following variables contributed independently to the diagnosis of TE: clinician's estimation of response to treatment at entry > 75%; absence of systemic antiprotozoal prophylaxis; seizures; headache; suggestive lesions on CT or MRI brain scan; and positive Toxoplasma serology. CONCLUSIONS: A linear logistic model is proposed which uses significant variables, which are readily available. This model gives good accuracy to classify suspected cases of TE.

AIDS-Related Opportunistic Infections↗

Comparative activities of new fluoroquinolones, alone or in combination with amoxicillin, trimethoprim-sulfamethoxazole, or rifampin, against intracellular Listeria monocytogenes.

We studied the activities of the new fluoroquinolones clinafloxacin, levofloxacin, ofloxacin, and sparfloxacin alone or in combination on the intracellular growth of Listeria monocytogenes. Against intracellular growth of the four strains tested, a similar reduction of the bacterial count was obtained with clinafloxacin at the dose of 10 x MIC (delta log10 CFU/ml = -2.19 +/- 0.24), with levofloxacin at 8 x MIC (delta log10 CFU/ml = -2.28 +/- 0.25), and with sparfloxacin at 4 x MIC (delta log10 CFU/ml = -2.16 +/- 0.21) after 24 h of incubation. The combination of the quinolones with trimethoprim-sulfamethoxazole or amoxicillin did not show a substantial increase in activity compared to the fluoroquinolone alone. Antagonism with rifampin was strongly suggested. No modification of the MIC was observed after 20 successive infections of HeLa cells and contact with subinhibitory concentrations of clinafloxacin, levofloxacin, and sparfloxacin for 24 h. We conclude that clinafloxacin, levofloxacin, or sparfloxacin could represent a therapeutic alternative to amoxicillin for the treatment of Listeria infections in adults, especially clinafloxacin, whose MIC is low (0.06 to 0.12 micrograms/ml), and whose best activity against intracellular L. monocytogenes was obtained at a concentration of 1.2 micrograms/ml, which is similar to clinically achievable levels. The results must be confirmed in an experimental model.

Amoxicillin↗

New types of primers (stair primers) for PCR amplification of the variable V3 region of the human immunodeficiency virus.

The aim of the study was to develop a reliable PCR method for the detection of viral genomes with frequent mutations like HIV and hepatitis C virus. A system of 'stair' primers is suggested which allows amplification of a genomic sequence despite the presence of mutations in the region of the primers. In this system, classical primers are replaced with primers composed of a mixture of equimolar oligonucleotides in which the 5' end remains constant (single sized fragment) and the 3' end is displaced base by base. By PCR, 'stair' primers (HIV set) were compared to single-sequence primers of 20 and 25 nucleotides chosen in the same hypervariable region of the HIV gp120 (on both sides of V3 region), as well as to classical primers chosen in the conserved pol (polV2) and gag (SK38-39) regions of the genome. Of 17 HIV isolates obtained by co-culture of lymphocytes from HIV-seropositive patients, 17/17 (100%) were amplified using stair primers, 14/17 (82%) with 25-nucleotide primers, and 12/17 (70%) with 20-nucleotide primers. Amplification occurred in 17/17 instances with polV2 primers and in 16/17 instances with SK38-39. In addition, 55 other isolates were tested comparatively using stair, polV2 and SK38-39 primers. All isolates were amplified using stair and SK38-39 primers and 54/55 isolates with polV2 primers. When applied to 22 extracts of patients' lymphocytes DNA, stair primers amplified all 22 extracts to the same degree as polV2 and SK38-39, whereas the 20 and 25 nucleotide primers chosen in the variable region were not as reliable. This new primer system allows reliable detection of variable genomic regions of the HIV genome and amplification of such regions directly in patient leukocytes. In addition, the contribution of this system to microbiology and human genetics in general may be important.

Base Sequence↗

The prognostic value of plasma viremia in HIV-infected patients under AZT treatment: a two-year follow-up study.

To determine the prognostic value of plasma viremia in long-term zidovudine (AZT)-treated HIV-infected patients, HIV-1 plasma viremia (PV) was quantified in 28 HIV-infected patients before and during AZT long-term treatment; the follow-up also included p24 antigenemia and CD4 cell counts. The variations of these markers during the follow-up period, the correlation with the clinical outcome (progressors versus nonprogressors), and the discrepancies between PV and surrogate markers were then analyzed. A significant and stable decrease in PV titer was observed in only nonprogressors (Friedman test, p < 0.005). At the end of follow-up, 11 (73%) of the 15 non-progressors were PV responders (patients who remained or became PV- long-term), whereas all the 13 progressors were PV nonresponders (patients who remained or became PV+). These results indicated a strong correlation between PV and clinical outcome (Fischer's exact test, p < 0.0001). The persistence, increase, or reappearance of viral replication appeared to be an important predictor of poor clinical outcome in HIV-infected patients under AZT treatment. This finding could provide a rational basis to help the clinician's decision in the clinical treatment of HIV-infected patients.

Acquired Immunodeficiency Syndrome↗