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Biomedical subjects

B Hirschel

Publications and source records attributed to B Hirschel.

At least 109 records · Page 6Linked to original sources
PubMed1996

Capnocytophaga canimorsus sepsis complicated by myocardial infarction in two patients with normal coronary arteries.

We describe two patients who had acute myocardial infarctions during episodes of Capnocytophaga canimorsus sepsis. C. canimorsus is associated with severe infection in patients who are immunocompromised; one of these patients had undergone splenectomy for Hodgkin's disease 11 years earlier, and the other consumed significant amounts of alcohol regularly. Both patients owned dogs that had licked them or produced minor skin wounds shortly before they became ill. Coronary angiographic findings were normal for both patients. The association of acute myocardial infarction and sepsis with a specific pathogen is unique. This finding suggests that endothelial damage and coronary thrombosis due to C. canimorsus sepsis is a possible mechanism of acute myocardial necrosis.

Animals↗
PubMed1996

Prognostic value of viremia in patients with long-standing human immunodeficiency virus infection. Swiss HIV Cohort Study Group.

Human immunodeficiency virus (HIV) viremia was evaluated in 73 patients with long-standing infection to investigate its relationship with clinical or biologic parameters and to assess its use as a predictor of clinical progression and death. After adjustment for other parameters, baseline HIV RNA level was significantly associated with baseline clinical stage and CD4 cell count. During follow-up (mean, 14.6 months), 16 patients died; 34 others had clinical progression of disease. In multivariate analysis, mortality was better predicted by baseline CD4 cell count (relative hazard [RH] for 100-cell decrease, 3.5; 95% confidence interval [CI], 1.5-8.2; P = .003) than by HIV RNA (P = .28) or clinical stage. HIV RNA level was the best predictor of clinical progression (RH for 1 log increase, 2.8; 95% CI, 1.6-4.9; P < .001). Monitoring of HIV RNA level may help to identify patients who might benefit from antiretroviral or prophylactic therapy.

Adult↗
PubMed1996

Reasons for failure of prevention of Toxoplasma encephalitis. Swiss HIV Cohort Study.

OBJECTIVE: To study whether absence of prophylaxis is a risk factor for cerebral toxoplasmosis, and to determine the reasons for absence of prophylaxis among AIDS patients diagnosed with Toxoplasma encephalitis (TE). DESIGN: Retrospective chart review and matched case-control study. PATIENTS: Patients (104 first episodes and 26 relapses of TE) were registered in the Swiss HIV Cohort Study from three centres from July 1992 to December 1994; 91 matched controls were included for 52 patients with a first episode, and 17 matched controls for 17 patients with relapse of TE. RESULTS: Prophylaxis was prescribed to 17 patients (16%) with a first episode and 19 patients (73%) with a relapse of TE. Reasons for the absence of prophylaxis included patient refusal (25%), non-proposal by physicians (17%), and drug intolerance (17%). Reduced absorption due to non-compliance, diarrhoea or vomiting was identified among 12 patients with a first episode and 14 patients with a relapse of TE. Absence of prescription of prophylaxis was associated with a 10-fold increased risk of a first episode of TE (odds ratio, 9.8; 95% confidence interval, 2.7-35.4) in the matched case-control study. CONCLUSIONS: TE continues to occur among patients not receiving prophylaxis. At least one-half of the cases may be prevented with better motivation of physicians and increased compliance of patients.

AIDS-Related Opportunistic Infections↗
PubMed1996

Combined therapy with zidovudine and L-697,661 in primary HIV infection.

OBJECTIVE: To decrease viraemia levels in primary HIV infection by using a combination of zidovudine (ZDV) and L-697,661. DESIGN: Four primary HIV-infected patients were treated for 6 months with ZDV, 250 mg twice daily, in association with the non-nucleoside reverse transcriptase inhibitor L-697,661 500 mg three times daily. Viraemia, proviral DNA, CD4 and CD8 cell counts were measured serially during 18 months. RESULTS: Viraemia decreased to undetectable levels (< 200 RNA copies/ml) in two patients. A third patient had a marked decrease followed by a rebound during therapy; viraemia levels did not vary markedly in the fourth patient. A rebound in viraemia levels was observed within 15 days of discontinuation of therapy in the three responding patients. Proviral levels evolved in parallel with viraemia but were always detectable in all patients. In the three patients with an initial decrease of viraemia, CD4 cell counts were within the normal range 2 months after initiation of therapy and did not markedly decrease after discontinuation of therapy. In the two patients with partial or no response of viraemia, mutations associated with low level of resistance to L-697,661 appeared during treatment. CONCLUSION: A marked decrease of viraemia can be achieved in some primary HIV-infected patients with combined therapy. Six months of treatment does not prevent a rebound of viraemia, which was observed within 15 days of interruption of therapy.

Adult↗
PubMed1996

Two different 16S rRNA genes in a mycobacterial strain.

Sequencing of the gene coding for 16S rRNA (16S rDNA) is a well-established method used to identify bacteria, particularly mycobacteria. Unique sequences allow identification of a particular genus and species. If more than one 16S rDNA is present on one mycobacterial genome, their sequences are assumed to be strictly or almost identical. We have isolated a slowly growing Mycobacterium strain, "X", identified by conventional biochemical tests as Mycobacterium terrae. Identification by amplification and direct sequencing of 16S rDNA yielded ambiguous results in two variable regions, suggesting the presence of different copies of the sequenced gene. Total DNA was digested by restriction enzymes and hybridized after Southern blotting to a probe representing about two-thirds of the 16S rDNA. Two copies of 16S rDNA were identified and cloned. By sequencing, the clones were of two different types, A and B, differing in 18 positions. Oligonucleotides specific to each copy of the 16S rDNA were used to distinguish the positions of the two genes observed in the Southern blot. We conclude that Mycobacterium strain "X" has two different copies of 16S rDNA. Variations in the sequence between two copies of 16S rDNA gene have been described in archaeobacteria, but not in mycobacteria. When placed in a phylogenetic tree together with other slowly growing mycobacteria gene A shows a common root with M. terrae, whereas gene B is placed separately.

Cloning, Molecular↗
PubMed1996

Mycobacteriosis caused by Mycobacterium genavense in birds kept in a zoo: 11-year survey.

We report on a disease in 27 birds (1 bird belonging to the order Coraciiformes, 3 to Piciformes, 4 to Galliformes, 7 to Psittaciformes, and 12 to Passeriformes) caused by fastidious mycobacteria. All birds were caged at the Antwerp Zoo and died suddenly between 1983 and 1994. Seventeen birds had no previous signs of disease, and 10 birds showed emaciation. Gross necropsy findings were generally nonspecific, but all the birds were smear positive for acid-fast bacilli (AFB). Histopathologic evaluation performed on 14 birds revealed predominantly intracellular AFB. Extracellular AFB were more abundant in advanced lesions, especially in necrotic areas. In the intestine the mucosal area was generally heavily infiltrated, suggesting an intestinal origin of the infection. There was extensive invasion of the lungs in most birds. In 11 birds sparse growth was obtained after at least 6 months of incubation on Löwenstein-Jensen medium or on Ogawa medium supplemented with mycobactin. Subculture was unsuccessful in all instances. The 16S rRNA gene sequence of the cultured organisms or tissues from seven birds revealed the characteristic signature sequence for Mycobacterium genavense. Direct bird-to-bird transmission in the zoo was unlikely, and the pathogenicity of M. genavense in birds seems to be limited. The source of M. genavense in nature and the epidemiology of the disease in birds remain obscure. As suspected for human cases of M. genavense infection, an oral route of infection has been suggested, and contaminated local water distribution systems may have been the source of the infection. Our study confirms that infections caused by M. genavense should be suspected in birds (especially in Passeriformes and Psittaciformes orders) that die suddenly without previous symptoms and that have AFB in tissues that are difficult to grow on conventional media.

Animals↗
PubMed1996

Risk factors for tuberculosis among HIV-infected patients in Switzerland. Swiss HIV Cohort Study.

The aim of this study was to determine the risk factors associated with tuberculosis among human immunodeficiency virus (HIV)-infected persons living in Switzerland, a country with low prevalence of tuberculous infection. We performed a nested case-control study and logistic regression. Cases (n = 239) were patients participating in the Swiss-HIV Cohort study (n = 7,103), diagnosed with bacteriologically confirmed tuberculosis. The rest of the cohort population was used as control. Patients from industrialized countries had a risk of tuberculosis similar to those from Switzerland (adjusted odds ratio (OR) 1.1; 95% confidence interval (95% CI) 0.7-1.5); whereas the risk among patients from Eastern Europe (OR 2.8, 95% CI 1.9-3.7), Brazil (OR 10.6; 95% CI 9.6-11.5), and Africa (OR 3.0; 95% CI 2.4-3.6) was markedly higher. Immune suppression, as indicated by low CD4 + cell count, was an independent risk factor for tuberculosis (OR 7.8; 95% CI 7.3-8.3 for patients with CD4 + < 50 cells.mm-3 compared to those with CD4 + > 500 cells.mm-3). Age, sex and HIV-transmission category did not appear to increase the risk of tuberculosis after adjustment for other patient characteristics. In conclusion, in countries of low prevalence of Mycobacterium tuberculosis infection, to originate from a country with high prevalence of tuberculosis infection and to have advanced immunodeficiency are significant risk factors for tuberculosis. They may be used to complement the tuberculin skin test in targeting patients for preventive chemotherapy.

Adult↗
PubMed1996

Predictive value of codon 215 reverse transcriptase mutation on the efficacy of didanosine in HIV-infected, zidovudine-experienced patients.

We investigated whether or not mutations at codon 215 in the HIV reverse-transcriptase-encoding gene predicted a lower efficacy of didanosine therapy, as defined by survival of patients and change in CD4 cell counts in 121 HIV-infected, zidovudine-experienced patients. A trend for shorter survival, although not reaching significance, was observed for patients with HIV strains with the reverse transcriptase codon 215 mutation (P = 0.07), but this trend disappeared after adjustment for initial CD4 cell counts. During the first 3 months on didanosine therapy, the increase in CD4 cell counts was greater in patients who were wild type at codon 215 than in those with the mutation at codon 215 (P = 0.03). These data suggest that there was a better initial CD4 response to didanosine therapy in patients with HIV without the mutation at codon 215, but that this response did not translate into increased survival.

Anti-HIV Agents↗
PubMed1995

Does the onset of tuberculosis in AIDS predict shorter survival? Results of a cohort study in 17 European countries over 13 years. AIDS in Europe Study Group.

OBJECTIVE: To assess the impact of tuberculosis on mortality in patients with AIDS. DESIGN: Community based cohort study. SETTING: 52 centres in 17 countries (AIDS in Europe study). SUBJECTS: 5249 patients who were alive and free of tuberculosis one month after the diagnosis of AIDS, enrolled between 1979 and 1989, and followed up until 1992. MAIN OUTCOME MEASURES: Onset of clinically active tuberculosis or death, or both. RESULTS: During a mean follow up period of 15 months 201 (4%) patients developed tuberculosis and 3889 (74%) died. Patients who developed tuberculosis survived significantly longer (median 22 months) than those who did not (median 16 months). This apparent survival advantage was due to patients who survived longer having more opportunity to develop tuberculosis (or any other disease). In models that took into account the time at which tuberculosis was diagnosed, the onset of tuberculosis was associated with a significant increase in mortality (adjusted relative hazard of death 1.34; 95% confidence interval 1.12 to 1.60). CONCLUSIONS: The onset of tuberculosis in patients with AIDS predicts a substantial increase in mortality. Whether this increased mortality is directly attributable to the tuberculosis remains uncertain. If the association is causal preventive chemotherapy and aggressive treatment of tuberculosis could improve survival in AIDS.

AIDS-Related Opportunistic Infections↗
PubMed1995

Early and prolonged decrease of viremia in HIV-1-infected patients treated with didanosine.

Fourteen patients previously treated with zidovudine were monitored for laboratory parameters and clinical events during 1 year after introduction of didanosine (ddI) monotherapy. Proviral human immunodeficiency virus type 1 (HIV-1) copy numbers (cell-associated DNA) and concentration of free virions (viremia) were determined using a semiquantitative polymerase chain reaction (PCR). High levels of circulating virus were detected in all patients (range, 17 to 5,934 x 10(3)/ml of serum). Within 4 weeks of therapy, a decrease of viremia (60 to 98%) was observed in nine patients. After 1 year of treatment, eight of these nine patients still had decreased viremia when proviral HIV DNA was decreased or stable, and CD4+ lymphocytes were stable or higher in seven of these eight patients. Antiviral effect was more pronounced in the six patients with CD4+ > 100/mm3 at entry, five of them belonging to the subgroup of the seven responding patients as compared to two of eight patients with CD4+ < 100/mm3. Clinical events in this small group were not statistically correlated with virologic parameters; however, responding patients had a tendency to stabilize or gain weight. This study suggests that measurement of viremia deserves further study as a marker of antiviral efficacy and might predict, even at 4 weeks, the beneficial potential of ddI.

AIDS-Related Opportunistic Infections↗
PubMed1995

[Primary HIV infection: an often suspected diagnosis but confirmed late].

We report the history and clinical findings in 17 patients with primary HIV infection (PHI) diagnosed in the first 6 months of 1994. 9 of these patients were infected through heterosexual contacts, 5 were women with, as the only risk factor, sexual contacts with infected men. 10 of the 17 patients were symptomatic and the diagnosis of PHI was suspected in 8 of these patients at their first medical visit. However, the laboratory investigations were incomplete since p24 Ag was only requested for one patient and this led to a delay in diagnosis. Sera collected at the time of the first medical visit were available for 4 symptomatic patients, and in all of them p24 Ag was detected in the absence of HIV specific antibodies. These data underline the frequent occurrence of HIV transmission by the heterosexual route and the need to search for both specific antibodies and p24 Ag at the time of PHI.

AIDS Serodiagnosis↗