Search PubMed⌕ Search

Biomedical subjects

H Agut

Publications and source records attributed to H Agut.

At least 91 records · Page 5Linked to original sources
PubMed1994

Identification of human herpesvirus 6 variants A and B by amplimer hybridization with variant-specific oligonucleotides and amplification with variant-specific primers.

Two distinct PCR-based procedures were evaluated for the detection and identification of human herpesvirus 6 (HHV-6) variants A and B in uncultured human samples. Variant-specific oligonucleotide hybridization (VSOH) is based on the amplification of two distinct regions of the HHV-6 genome, followed by hybridization of amplimers with variant-specific oligonucleotide probes. Variant-specific primer PCR (VSPP) is based on the amplification of each variant by using variant-specific primers. The study of 10 well-characterized HHV-6 strains allowed us to demonstrate the high sensitivity and specificity of both methods. With variant mixtures, however, some limitations of VSOH were evidenced and VSPP was required to obtain unambiguous results. The combination of VSOH and VSPP was applied to the direct study of 300 peripheral blood mononuclear cell samples from French subjects. HHV-6 was detected in 15 samples: 11 corresponded to variant B, 3 corresponded to variant A, and 1 corresponded to a mixture of both variants.

Adolescent↗
PubMed1994

SCID-Hu mouse as a model for human lung HIV-1 infection.

HIV induces a multi-organ infection with a dual tropism for both lymphocytes and monocytes/macrophages. The lung is a target both for HIV infection and HIV-related opportunistic infections. The SCID mouse has provided the opportunity to develop a small animal model for HIV infection. However, HIV-1 infection of the human fetal thymus and liver (SCID Liv/Thy) implanted in these mice occurred only after direct intraimplant injection of HIV-1 and the resultant HIV-1 infection was restricted to the human thymus. Here we report that human foetal lung can develop in SCID Liv/Thy mice resulting in the development of normal human alveolar and bronchiolar lung compartments which can be productively infected with cell-free HIV-1 virus, leading to a systemic and bifocal infection. This SCID-Hu model should be useful for studying AIDS physiopathology, human viruses with lung tropism and for helping to define gene therapy protocols in lung human cells in vivo.

Acquired Immunodeficiency Syndrome↗
PubMed1994

High variability of the gag/pol transframe region among HIV-1 isolates.

The overlapping region of gag and pol genes of human immunodeficiency virus type 1 (HIV-1) also called transframe region, contains the frameshift locus from gag to pol. This region encodes both the protein p6, the function of which remains unclear, and a putative transframe protein covently linked to the N-terminus of the viral protease within Gag/Pol protein precursor. We have investigated the variability of the transframe region among nine HIV-1 isolates obtained from Congolese AIDS patients. Nucleotide sequences were determined using the polymerase chain reaction and the direct sequencing of amplified products. The sequences of Congolese isolates markedly differed from one another and from other reference HIV-1 strains by both insertion-deletion events and numerous base substitutions. Several putative cleavage sites of precursor polypeptides were modified. When compared to consensus ones the amino acid sequences of p6 protein were very different among divergent HIV-1 isolates, except for a limited group of 10 conserved amino acids.

Amino Acid Sequence↗
PubMed1993

Antigenic and genetic differentiation of the two putative types of human herpes virus 6.

Ten human herpes virus 6 (HHV-6) strains from different origins were studied using reactivity to monoclonal antibodies and polymerase chain reaction analysis. Using immunofluorescence and neutralization assays, two monoclonal antibodies gave a positive reaction with the ten strains while three others only reacted with a fraction of these strains. This differential reactivity permitted segregation of the ten strains into two non-overlapping antigenic groups, designated as I and II. DNA was amplified from two regions of HHV-6 genome corresponding to the putative large tegument protein (LTP) gene and major capsid protein (MCP) gene, respectively. The restriction analysis of amplified products using HindIII for LTP and HaeII for MCP showed identical patterns among the strains belonging to the same antigenic group while BglII, TaqI and ClaI provided distinct patterns among group II strains. The nucleotide sequence of amplified products was determined and homology was found to be equal to or greater than 99% within each group whereas it was 96% between both groups. The number of amino-acid changes was higher when comparing two strains of different groups than when comparing two strains of the same group. The converging results of antigenic and genetic analyses led us to consider HHV-6 groups I and II as two distinct types of HHV-6 species.

Adult↗
PubMed1993

[Quantitative viremia and p24 antigenemia in short-term follow-up of the treatment with zidovudine in twenty HIV infected patients].

The authors emphasize the interest of detecting HIV p24 antigen after immune complexes dissociation as well as changes in cellular viremia titers in the therapeutic follow-up of HIV infected patients. A significant decline of cell virus titers was found in 4-8 weeks among 13 of 20 zidovudine treated patients. A significant decrease of immune complexes dissociated p24 antigenemia was noted in 11 out of 17 patients.

Acquired Immunodeficiency Syndrome↗
PubMed1993

In situ hybridization of HIV-1 RNA in retinal vascular wall.

In situ hybridization of human immunodeficiency virus-1 (HIV-1) has been performed on eight eyes from eight distinct acquired immune deficiency syndrome patients (three cases had a normal fundus examination and five presented with cytomegalovirus retinitis). The eyes were removed at autopsy and frozen immediately. Contiguous 10-mu cryostat sections were obtained and tested with a HIV probe labeled by nick-translation with [35S]-ATP. HIV-1 RNA was detected in the retina of two acquired immune deficiency syndrome patients. The first positive case presented with typical ophthalmological and histopathological cytomegalovirus retinitis, the second one was not related to cytomegalovirus, according to clinical or histopathological classical criterias. HIV-1 was localized in retinal vascular walls. This shows that there is an active replication of HIV in retina of some acquired immune deficiency syndrome patients.

Acquired Immunodeficiency Syndrome↗
PubMed1993

[Antiviral chemotherapy: mechanisms of action, evaluation of activity, resistance and future developments].

Antiviral chemotherapy is based on the selective inhibition of intracellular virus multiplication. Inhibitors of viral DNA polymerases perfectly exemplifies this mode of action. In spite of their selectivity, some of these drugs are cytotoxic and all remain unefficient against latent viruses. Evaluation of antiviral activity requires in vitro sensitivity tests, in vivo studies on animals and virological analyses during clinical trials. This evaluation needs well standardized assays. The emergence of in vitro resistance reflects the occurrence of mutations regarding target enzymes. Clinical significance of antiviral drug resistance needs to be assessed in many circumstances, even if its association with immunodeficiency often leads to a clear therapeutic failure. Further developments will include the synthesis of novel inhibitors, study of drug associations and improvement of virological diagnosis techniques relevant to therapy.

Acyclovir↗
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↗