PubMed Health⌕ Search

Biomedical subjects

H Agut

Publications and source records attributed to H Agut.

At least 19 recordsLinked to original sources
PubMed1992

Comparative assessment of quantitative HIV viraemia assays.

OBJECTIVE: To compare two published methods for determining plasma viraemia in HIV-seropositive patients, with reference to a cellular viraemia assay. PATIENTS, PARTICIPANTS: Three patient groups were defined according to CD4 cell count: group I, less than 200 x 10(6)/l (23 patients); group II, 200-500 x 10(6)/l (18 patients); and group III, greater than 500 x 10(6)/l (13 patients). METHODS: The two reported methodologies were applied to all fresh samples, simultaneously and on the same day. RESULTS: The two techniques did not differ significantly in the detection of plasma viraemia: 82.3% of group I patients and 55% of group II patients were positive, while all group III patients were negative. Cellular viraemia was positive for 96% of the overall population. CONCLUSIONS: These results, obtained in a network of seven French laboratories involved in clinical trials, confirm that both plasma viraemia and cellular viraemia are useful virological markers.

AIDS Serodiagnosis↗
PubMed1992

Multicentre quality control of polymerase chain reaction for detection of HIV DNA.

OBJECTIVE: Seven French laboratories tested the specificity and sensitivity of the polymerase chain reaction (PCR) for the detection of HIV-1 DNA. METHODS: Following its own PCR protocols, each laboratory independently tested blind two panels of 20 coded peripheral blood mononuclear cell samples collected from HIV-1-seropositive individuals and from HIV-1-seronegative individuals at high or low risk of HIV infection. For the first panel, laboratories were free to select type and number of primers; for the second, all were required to use the two primer pairs Pol 3/4 and MMy 9/10' (Nef 1). RESULTS: False-positive and false-negative results were observed in all laboratories (concordance with serology ranged from 40 to 100%). In addition, the number of positive PCR results did not differ significantly between high- and low-risk seronegatives. The use of crude cell lysates in DNA preparation produced the same PCR results as phenol-extracted DNA. Discrepancies between laboratories indicated that factors other than primer pairs contributed strongly to laboratory variability. CONCLUSIONS: Our results emphasize the importance of both positive and negative controls in PCR and demonstrate the value of multicentre PCR quality control.

Base Sequence↗
PubMed1992

Susceptibility of HIV-1 isolates to zidovudine: correlation between widely applicable culture test and PCR analysis.

Thirteen isolates of human immunodeficiency virus type 1 (HIV-1) obtained in coculture with peripheral blood lymphocytes were tested for in vitro susceptibility to zidovudine (ZDV). Seven isolates were obtained from patients who had never been treated with ZDV and six from patients receiving the drug. The seven isolates from untreated patients and four of six from treated patients were susceptible to ZDV. The two isolates from the patients treated for the longest periods were resistant to the drug. The presence of mutations at critical positions of the reverse transcriptase gene was investigated by direct sequencing of polymerase chain reaction (PCR)-amplified DNA and four isolates were found to be mutants. An isolate from an untreated patient showed a change at residue 70 of the reverse transcriptase and an isolate from a patient treated for 4 months showed a change at residue 67. A change at residue 215 was found only for the two drug-resistant isolates, which correlated with the results obtained by Larder et al. using isolates from MT-2 cell cocultures. These results suggest that any HIV isolate provided by conventional coculture could be confidently tested for ZDV susceptibility in order to study the emergence of resistance during long-term therapy.

Base Sequence↗
PubMed1991

[Study of human immunodeficiency virus in the cerebrospinal fluid. Value and limitations].

Several markers of HIV infection can be detected in the cerebrospinal fluid, including viruses that are replicable in cell cultures, viral antigens and, at an early stage, stigmas of immunization against the virus. Some studies make a distinction between HIV isolated in cerebrospinal fluid and in serum. Cerebrospinal HIV isolates differ from serum isolates in their macrophage tropism, their antigenicity and their low cytotoxicity, but there is little difference in their capacity for replication. Studies aimed at finding virological markers to diagnose HIV-induced neurological lesions have given discordant results. Longitudinal studies are necessary to determine prognostic markers. New techniques, such as amplification by polymerase chain reaction, will perhaps provide new data.

Biomarkers↗
PubMed1991

Genetic variability affects the detection of HIV by polymerase chain reaction.

Nine isolates of HIV-1 obtained from Congolese AIDS patients were amplified by the polymerase chain reaction (PCR) using primer pairs and oligomer probes derived from the HIV-1 LAV-BRU (BRU) sequence. When compared to BRU, two isolates exhibited a significant decrease of PCR efficiency with a given primer pair. Moreover, the DNA amplified from two other isolates did not hybridize with the corresponding probe despite efficient PCR. Base substitutions were detected in the regions of proviral genomes involved in oligonucleotide annealing and were assumed to be responsible for the failure of both amplification and probing. Our data confirm that the genetic variability of HIV-1 may reduce the efficiency of PCR as a diagnostic procedure, especially in the case of African isolates.

Base Sequence↗
PubMed1991

Virological markers in the cerebrospinal fluid from HIV-1-infected individuals.

We analysed 127 specimens of cerebrospinal fluid (CSF) from 118 HIV-1-infected individuals at different stages of infection. Intrathecal antibody synthesis was evident in 23 samples tested and was more frequently directed against HIV than against rubella virus, herpes simplex virus, varicella zoster virus or cytomegalovirus. HIV was isolated from only 14% of the 127 CSF specimens, but from 82% of CSF-paired blood samples. HIV antigen was detected in 12% of CSF specimens and 44% of paired plasma samples. Twenty specimens analysed using the polymerase chain reaction (PCR) detected proviral DNA in 75% of CSF specimens. The low rate of virus recovery from CSF was caused by neither the freezing of specimens prior to culture nor therapy. In contrast, virus isolation from CSF was significantly associated with CSF cell count. Virus isolation and antigen detection in CSF were not correlated with either the Centers for Disease Control disease stage or the peripheral CD4+ lymphocyte count, whereas viraemia was significantly associated with a low CD4+ lymphocyte count. Moreover, virus isolation and antigen detection in CSF were not associated with symptoms of subacute HIV encephalitis, suggesting that these markers are not of potential value in the diagnosis of HIV-specific neurologic complications. The value of PCR in this field merits further investigation.

AIDS Dementia Complex↗
PubMed1991

Several groups among human herpesvirus 6 strains can be distinguished by Southern blotting and polymerase chain reaction.

Eight human herpesvirus 6 (HHV-6) strains were studied by Southern blot and polymerase chain reaction. DNA from infected cells was digested by a panel of restriction enzymes and hybridized with cloned BamHI fragments corresponding to about 30% of the HHV-6 strain SIE genome. In parallel, this DNA was amplified by polymerase chain reaction using pairs of primers derived from the strain SIE nucleotide sequence. Subsequently, amplification products were analyzed by hybridization, digestion with restriction endonucleases, and partial nucleotide sequencing. Overall results indicated that all strains were closely related to one another. However, concordant differences in restriction patterns allowed at least two groups to be distinguished, typified by strains SIE and HST, respectively. Differences between the two groups were found to reflect a limited number of punctual changes in nucleotide sequences. These results strengthen the idea of a unique HHV-6 species with genetic polymorphism. In addition, this study provides useful markers for the diagnosis and molecular epidemiology of HHV-6 infections.

Base Sequence↗
PubMed1991

Correlations between virus infection and pathogenicity in humans.

Infection is not synonymous with disease. Infection refers to the multiplication or the persistence of a virus in tissues while pathogenicity refers to the emergence of disease in the infected host. Pathogenicity is the result of a competition between the growth of the virus and the host response to infection, and its genesis involves many intricate factors. Consequently, most viruses of medical interest exhibit a wide spectrum of pathogenicity ranging from asymptomatic infection to lethal disease. The study of pathogenicity is far more complex than the recognition of infection. Cell cultures, animal models and molecular biology investigations have provided substantial insights both into the virulence of viruses and the susceptibility of the host. However, the prediction of disease often remains hazardous whereas the detection of a virus can now be obtained in most cases by the combination of classical methods with recent molecular techniques. Therefore the prevention of virus diseases transmitted by biologicals is logically founded on the prevention of virus infections, which implies a constant adaptation of safety control procedures to the rapid evolution of knowledge in medical virology.

Biological Products↗