Detection of human and animal rotavirus sequences in drinking water.

Reverse transcription-PCR analysis of drinking water in the homes of 56 children suffering from rotaviral gastroenteritis has shown the presence of the rotavirus genome in four samples. These strains were different from human rotaviruses detected in the children's feces, as determined by sequencing of the VP7-amplified fragments-three of them of animal origin (porcine or bovine) and one of human origin.

Serologic and genetic characterization of HIV type 1 subtypes on Reunion Island.

The aim of this study was to determine the HIV subtypes present on Reunion Island, a French island located in the Indian Ocean, where the first case of AIDS was diagnosed in 1987. Paired sera and blood samples were collected between September 1996 and September 1997 from 53 HIV-1-positive patients. Subtyping was performed by serotyping with a previously described subtype-specific enzyme immunoassay (SSEIA) and by genotyping with the heteroduplex mobility assay (HMA). When samples gave uninterpretable results with either of the methods, or discordant results, the V3 env region was sequenced and genetic subtypes were determined by phylogenetic analysis. Genetic subtyping showed that 48 of 53 patients were infected with HIV-1 subtype B (90.5%). This high prevalence of subtype B on Reunion Island is probably due to the regular exchanges with metropolitan France. The other five patients were infected with subtype A (9.5%); they had been directly linked to African populations. Of the 48 subtype B samples, 44 (91.7%) were correctly subtyped by SSEIA and 43 (89.6%) by HMA. However, the SSEIA did not allow the subtyping of A strains in three of five patients. Thus, the SSEIA could be an alternative routine technique for screening subtype B versus nonsubtype B HIV-1 strains.

Heat stress-induced B1 receptor synthesis in the rat: an ex vivo study.

1. This ex vivo study was performed to characterize B1 receptor induction in rats submitted to heat stress. Changes in aortic isometric tension were recorded after a 90 min in vitro incubation with [des-Arg9]-bradykinin. B1 receptor mRNA were detected in aorta and heart using RT-PCR technique. 2. Aortic rings from sham rats did not respond to [des-Arg9]-bradykinin. In contrast, this agonist induced a concentration-dependent relaxation of aortic rings from rats submitted to lipopolysaccharide (LPS) treatment or to heat stress 24 h earlier. 3. The concentration-dependent relaxation induced by [des-Arg9]-bradykinin on aortic rings from heat-stressed rats was abolished by [des-Arg10]-HOE 140, a selective B1 receptor antagonist. 4. In endothelium denuded aortic rings from heat-stress rats, [des-Arg9]-bradykinin induced a concentration-dependent constriction. 5. Pretreatment of intact aortic rings from heat-stress rats with the cyclo-oxygenase inhibitor, diclofenac (1 microM) did not prevent the concentration-dependent relaxation in response to [des-Arg9]-bradykinin. In contrast. NO synthase inhibition with N(omega)-nitro-L-arginine methyl ester (30 microM) totally prevented the vasorelaxant response. 6. B1 receptor mRNA were not detected in aorta and heart from sham animals but were present in tissue from heat-stressed and LPS-treated rats. 7. In conclusion, our results suggest that heat stress induces a transcriptional activation of the B1 receptor gene. The induction of B1 receptors leads to an endothelium- and NO-dependent vasorelaxant response to [des-Arg9]-bradykinin.

Transient infection of astrocytes with HIV-1 primary isolates derived from patients with and without AIDS dementia complex.

We have studied the replication capacity of primary HIV-1 isolates obtained from four AIDS patients in astrocytes. Two patients (P1 and P2) had neurological manifestations without AIDS Dementia Complex (ADC). The other two patients (P3 and P4) had ADC. Two astrocytoma cell lines and normal fetal astrocytes were inoculated with each of these four viral isolates. Viral DNA and mRNA synthesis and also protein accumulation were followed at various times after infection. We found that tumoral as well as fetal astrocytes were susceptible to HIV-1 infection. Three of four viral isolates (P2, P3, P4) were able to infect astrocytes. Both ADC viral isolates (P3, P4) infected astrocytes with identical transcriptional patterns: rev, nef and unspliced mRNAs were expressed for 2 days after infection. The non-ADC patient (P2) with the isolate leading to viral replication in astrocytes had an HIV-1 associated multifocal demyelinating neuropathy. In this case, only nef and unspliced mRNAs were detected a few days after virus inoculation. In all cases, infection of astrocytes was transient and the level of unspliced mRNAs in infected astrocytes was lower than in chronically HIV-1 infected T cells. More extensive work would allow a better understanding of the role of astrocytes in ADC.

Blood monocytes infected in vivo by HIV-1 variants with a syncytium-inducing phenotype.

Extensive data have been obtained on sequence changes in the V3 region of the HIV-1 envelope protein that are associated with in vitro biological properties such as cell tropism and syncytium-inducing capacity. However, so far this concerned viruses isolated from peripheral blood mononuclear cells and thus did not discriminate between variants present in T lymphocytes or in monocytes. In this study, we analyzed viral sequences derived separately from uncultured T lymphocytes, blood monocytes, and plasma of an HIV-1-infected patient showing a neurological evolution of the disease. Sequences related to the V3 region and 18 amino acids downstream were obtained from 48 clones after PCR amplification. One predominant viral sequence close to the monocytotropic/non-syncytium-inducing (NSI) consensus sequence was observed in the three blood sources. Two viral species were specifically identified in monocytes (43% of the clones), showing clear differences from the consensus sequence and exhibiting the genetic determinants associated with the SI phenotype. Plasma-derived viruses with a similar V3 loop were obtained on in vitro isolation. Analysis of the biological properties of these selected viruses confirmed their monocytotropism and the syncytium-inducing phenotype as expected by the cell type in which the sequences were observed and the charge of the V3 loop. Structural analysis of these variants suggested an intermediate structure between NSI/monocytotropic and SI/lymphotropic V3 loops. Thus, in vivo circulating monocytes could be a reservoir for distinct HIV-1 variants with potential SI characteristics, at least in later stages of infection. Studying such variants over the course of the infection may shed light on their involvement in disease manifestations.