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Biomedical subjects

J M Huraux

Publications and source records attributed to J M Huraux.

At least 19 recordsLinked to original sources
PubMed1992

Liver/kidney microsome antibody type 1 and hepatitis C virus infection.

Recent studies have shown that hepatitis C virus antibodies are present in a large proportion of patients with autoimmune hepatitis type 2. We have studied 83 patients with liver/kidney microsome antibody-positive type 1 hepatitis. Hepatitis C virus antibodies were sought in every case by second-generation tests (hepatitis C virus enzyme-linked immunosorbent assay and recombinant immunoblot assay). Hepatitis C virus RNA sequences were sought in 22 patients (12 with recombinant immunoblot assay-positive results and 10 with recombinant immunoblot assay-negative results) by means of polymerase chain reaction and by use of primers located in the 5' noncoding region. Sixty-four patients (77%) had positive results for hepatitis C virus antibodies in the enzyme-linked immunosorbent assay test, and 41 (49.3%) were confirmed by recombinant immunoblot assay. Hepatitis C virus RNA sequences were found in all the recombinant immunoblot assay-positive patients but in none of the 10 who were recombinant immunoblot assay-negative. The recombinant immunoblot assay-negative patients were younger than those who were positive (13 +/- 11 vs. 50 +/- 11 years) and had higher gamma-globulin levels and liver/kidney microsome antibody-positive type 1 titers (61% had a titer of 1:1,000 or more, vs. only 17% of the recombinant immunoblot assay-positive patients).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1992

Intrathecal synthesis of proteins: from immunoglobulins to prealbumin.

The assessment of proteins intrathecal synthesis (ITS) is an essential step in the CSF analysis. It can be established qualitatively by different ratios and quantitatively by empirical formulae. Schuller and Sagar's formula was proposed 10 years ago for the calculation of IgG ITS. From this calculation, the antibody specific activity of intrathecal immunoglobulins may be also evaluated. The same principle may be used for complement components and for different other CSF proteins. Two examples (concerning Fibronectin and prealbumin ITS) demonstrate the usefulness of this approach, which can be programmed by a computer.

Acquired Immunodeficiency Syndrome↗
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

[Various approaches to virologic diagnosis and the corresponding sampling].

Owing to the diversity of viral infections and to the high cost of laboratory techniques the diagnostic approach must be chosen according to clinical data. The two ways of approaching the viral diagnosis are of unequal value: detection of the virus or its constituents is preferable to detection of specific immune response. The virus or its constituents is either detected directly in the specimen collected (rapid diagnosis) or isolated after inoculation of a cellular system. Several methods can be used for rapid diagnosis: the virus may be visualized at electron microscopy; immunological techniques detect viral antigens bound to specific antibodies, the binding being revealed by immunofluorescence, enzyme-linked immunoassay or passive agglutination; detection of viral nucleic acids is particularly useful when the virus is difficult to isolate or the antigenic expression difficult to detect, or when immune response is deficient. Virus isolation from a cellular system is usually performed by cell cultivation. Typing of the isolated virus is effected by the same immunological methods os those used for rapid diagnosis, but also by seroneutralization of agglutination inhibition. Genic amplification, of CPR, is a special technique which detects the virus in the specimen studied after its genome has been amplified in an acellular system. Owing to technical problems and difficulties of interpretation, for the time being PCR is reserved to research. Success in diagnosis depends on the quality of the specimens and on their transfer to the laboratory under adequate conditions. Practitioners therefore play a major role in the diagnosis of viral diseases by prescribing the appropriate examinations, providing clinical information and making sure that the specimens are correctly collected.

Blood Specimen Collection↗
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

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↗
PubMed1990

Simplified test for detecting the resistance of herpes simplex virus to acyclovir.

The detection of herpes simplex virus (HSV) antigen by means of an enzyme amplified ELISA was investigated for rapid screening of acyclovir (ACV) resistance. Vero cell monolayers were inoculated in the presence of different concentrations of ACV. When cytopathic effect was present, the culture supernatants were tested by ELISA. The absorbance values were found to correlate with the results of virus yield and plaque reduction assays. The comparison between absorbance values obtained in the presence of 10 microM ACV and in the absence of drug provided the basis for a simplified sensitivity test. The use of a single ACV concentration allowed discrimination between ACV-resistant and ACV-sensitive reference strains, the detection of ACV-resistant virus mixed in the proportion of 10% with ACV-sensitive virus, and a study of the emergence of an ACV-resistant virus population in serial samples taken from experimental rabbit keratitis. The simplified susceptibility assay is a sensitive and convenient method for rapid screening of HSV resistance to ACV.

Acyclovir↗
PubMed1990

Perspectives in antiviral chemotherapy.

The current progress in antiviral therapy is related to our better understanding of the viral multiplication, with potential targets for specific antiviral action at each step of the multiplication cycle inside the infected cell. Amantadine and Rimantadine are anti-influenza A drugs interfering with the penetration and the release of the virus. Most of the other antiviral drugs which are clinically available have the same target in common, namely the viral DNA polymerase. This holds true for modified nucleosides such as Acycloguanosine (Acyclovir), DHPG, Adenine-Arabinoside, Azidothymidine as well as pyrophosphate derivatives such as phosphonoformic acid. Unfortunately the antiviral chemotherapy must confront 3 obstacles: 1) a possible interference with the normal cellular metabolism, leading to residual cytotoxic side effects; 2) the genetic variability of the viruses, producing drug-resistant mutants and 3) the inability of any antiviral chemotherapeutic agent known to date to eradicate latent viral infection. A new approach of the control of latent infection is suggested with anti sense oligonucleotides of hybridons.

Animals↗