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F Barin

Publications and source records attributed to F Barin.

At least 73 records · Page 4Linked to original sources
PubMed1994

[Screening tests of anti-HVC antibodies used in France. Analysis of sensitivity].

The results concerning the hepatitis C antibodies screening tests sensitivity are presented by Viral Hepatitis Study Group of the French Society of Blood Transfusion. This evaluation was carried out in 1993, with five tests available for Hepatitis C Viral (HCV) antibodies screening. Several panels of human blood samples, collected by members of Viral Hepatitis Study Group, were used. For those specimens the data about whole serology (various reactivities against viral antigens) clinical history and other explorations (molecular biology, liver histology, other viral infections) are described. If possible all those results are used to describe some interpretation criteria for the HCV serology and sensitivity obtained for each screening test.

Enzyme-Linked Immunosorbent Assay↗
PubMed1994

Multicenter evaluation of a fully automated screening test, VIDAS HIV 1 + 2, for antibodies to human immunodeficiency virus types 1 and 2.

A multicenter study was done to evaluate the sensitivity, specificity, and efficiency of a new screening test for the simultaneous detection of human immunodeficiency virus type 1 and 2 (HIV-1 and HIV-2) antibodies. The VIDAS HIV 1 + 2 (bioMérieux, Marcy l'Etoile, France) is a fully automated enzyme-linked fluorescent immunoassay that uses synthetic peptides from immunodominant regions of gp41 of HIV-1 and gp36 of HIV-2 as antigens. A total of 2,984 samples were evaluated with this system in six different laboratories, and the results were compared to those obtained with other enzyme-linked immunosorbent assays. The VIDAS HIV 1 + 2 assay showed a very good performance in terms of sensitivity (100%) and specificity (99.6%), requiring minimal manipulation and short incubation time (32 min) to give results similar to or better than those of the other enzyme-linked immunosorbent assays used for screening.

Enzyme-Linked Immunosorbent Assay↗
PubMed1994

Hepatitis C virus (HCV)-specific in vitro antibody secretion by peripheral blood lymphocytes: correlation with progression of disease and HCV RNA in HCV antibody-positive patients.

Hepatitis C virus-specific in vitro antibody production (HCV IVAP) by peripheral blood lymphocytes in 53 HCV antibody-positive patients was investigated in comparison with alanine aminotransferase (ALT) levels and HCV RNA in serum samples. All 29 HCV IVAP-positive patients were HCV RNA positive; 26 had elevated ALT levels. Among the 24 HCV IVAP-negative patients, 16 were HCV RNA negative, with 12 presenting normal ALT values. These data indicate that HCV IVAP results are highly correlated (P < 0.001) with HCV RNA results and ALT levels. Our study indicates that HCV IVAP can be used as a novel assay in the diagnosis and pathogenesis exploration of HCV infection.

Adult↗
PubMed1993

Interaction between a membrane-associated serine proteinase of U-937 monocytes and peptides from the V3 loop of the human immunodeficiency virus type 1 (HIV-1) gp120 envelope glycoprotein.

A trypsin-like proteinase which is inhibited by recombinant gp120 and by synthetic peptides of various lengths spanning the conserved sequence of the V3 loop has been purified and partially characterized from a U-937 cell membrane extract. V3 loop peptides behave as competitive inhibitors of the enzyme, while gp120 exerts a tight-binding inhibition, reacting in stoichiometric amounts with the proteinase to provide significant inhibition. Though the properties of the U-937 membrane proteinase towards gp120 and synthetic peptides of the V3 loop resemble those of the Molt-4 T-cell tryptase TL2, these two proteinases differ by their physicochemical properties and their susceptibility to other inhibitors of serine proteinases. These results give support to the concept of a membrane-associated proteinase as a complementary or alternative receptor to the CD4, for allowing virus to enter host cells and thus spreading HIV infection.

Amino Acid Sequence↗
PubMed1993

[Viral risks associated with blood transfusion].

The presence of viruses in blood cells or plasma from asymptomatic donors is the major risk of transmitting an infectious agent through blood transfusion. The main viruses involved are hepatitis viruses and retroviruses. The risk of transmitting hepatitis B virus (HBV) and hepatitis C virus (HCV) has been progressively and efficiently reduced in the last years by the successive introduction of hepatitis B surface antigen (HBsAg) screening, elevated serum alanine aminotransferase (ALT), antibody to hepatitis B core (HBc Ab), and more recently antibody to hepatitis C virus (HCV Ab). The risk of transmitting human retroviruses like human immunodeficiency virus (HIV) and human T-cell leukemia/lymphoma virus (HTLV) has also been reduced drastically thanks to screening for corresponding antibodies. However, except for HBs Ag screening, the immunoassays used for HCV, HIV, or HTLV only detect antibodies. Therefore, although they are infectious, a few blood units may be not discarded. The efficacy of preventive measures depends on the incubation time, the infectivity during this silent phase, and the sensitivity of screening procedures. Human cytomegalovirus (HCMV) and parvovirus B 19 are responsible for common infections. Consequently, 30% to more than 50% adults have serologic evidence of past infection. However, both viruses may cause severe primo-infections in some circumstances, especially in pregnant women or immunodeficient individuals.

Cytomegalovirus Infections↗
PubMed1993

High antigenic cross-reactivity of the V3 consensus sequences of HIV-1 gp120.

The principal neutralization determinant (PND) of the human immunodeficiency virus type 1 (HIV-1) is located within the variable V3 region of the external envelope protein gp120. Although it is recognized that V3 sequences induce antibody response with restricted neutralization activity in vitro, we observed that the V3 consensus sequences representing North American/European and African isolates were highly cross-reactive, binding 94 and 77%, respectively, of sera collected from HIV-1 individuals originating from various parts of the world. Even HIV-1-positive sera from some East African residents, infected by strains whose V3 loop sequences are undoubtedly distinct from the North American/European consensus V3 loop sequence, reacted better to the V3 North American/European consensus peptide than to African-specific V3 sequences. Results indicate that the V3 consensus sequences represent the best candidates for optimal cross-reactivity with a wide variety of strains. Furthermore, using immunoassays for antibodies to prototype-specific V3 sequences, it is shown that HIV-1 strains related to the MN group are prevalent in West Africa, indicating either a West African origin of the MN-related viruses or more probably an introduction of this group of viruses through European/North American contacts.

Africa↗
PubMed1993

Antigenic variation of the dominant gp41 epitope in Africa.

OBJECTIVE: To determine the value of (combinations of) synthetic peptides representing immunodominant sites on HIV-1/HIV-2 transmembrane proteins for the detection and discrimination between HIV-1 and HIV-2 infection in various populations. DESIGN AND METHODS: Two 24-mer synthetic peptides derived from immunodominant sites on the HIV-1 and HIV-2 transmembrane proteins were used separately, in combination (env 1/2), and in combination with recombinant p24 (p24/env) in enzyme-linked immunosorbent assays. RESULTS: Positive reactions with env-1 were found in 150 out of 150 (100%) samples from Dutch AIDS patients, 60 out of 60 (100%) samples from Dutch homosexual men obtained 1 year after HIV-1-antibody seroconversion, 29 out of 30 (96.7%) samples from these men obtained at the time of HIV-1-antibody seroconversion, 40 out of 41 (97.6%) samples from East Africans with AIDS-related symptoms, and three out of 29 (10.3%) samples from West Africans with HIV-2 infection (including a sample from an individual infected with both HIV-1 and HIV-2). Positive reactions with env-2 in these study populations were 11 out of 150 (7.3%), nine out of 60 (15%), none out of 30 (0%), 25 out of 41 (60.9%) and 29 out of 29 (100%), respectively. In the samples with dual reactivity, true versus cross-reactivity could generally be differentiated on the basis of large differences in optical density values in the respective assays. All samples reacted positively with p24/env; 308 out of 310 (99.3%) were positive in the env 1/2 assay. Four East African samples that had negative or only weakly positive reactions with env-1 showed a noticeably stronger reaction with variant peptides derived from Central African isolate sequences. In all samples from HIV-1-infected Dutch homosexual men, the strongest signal was detected using the env-1 peptide sequence, which is derived from European and American isolates. CONCLUSIONS: Small peptide antigens may permit the detection of strain-specific antibodies, allowing serological characterization of HIV isolates.

Africa↗
PubMed1993

Prevalence and significance of hepatitis C virus (HCV) viremia in HCV antibody-positive subjects from various populations.

Hepatitis C virus (HCV) infection is currently assessed by detection of antibodies to HCV with immunoassays. However, in the absence of an in vitro system to isolate the virus, or an immunoassay to identify HCV antigen in blood, an ongoing acute or chronic HCV infection can be diagnosed only by detection of HCV RNA by polymerase chain reaction. We used a reverse transcription-nested polymerase chain reaction to detect an HCV 5' noncoding viral RNA sequence in serum specimens collected from anti-HCV-positive individuals belonging to different risk groups and compared the results with those obtained with a prototype recombinant immunoblot assay (Chiron HCV SIA prototype recombinant immunoblot assay [RIBA]) containing four different viral peptides (c22, c33c, c100, and NS5). The prevalence of HCV viremia ranged from 25.9% in HCV antibody-positive blood donors to 92% in HCV antibody-positive hemophiliacs. Elevated alanine aminotransferase values in HCV antibody-positive patients were clearly associated with viremia. Ninety-six percent of HCV RNA-positive patients reacted to two viral antigens or more, compared with only 64% of HCV RNA-negative patients. Contrary to previous reports, HCV viremia was not associated with either the presence or the absence of a particular antibody specificity. The newly introduced NS5 peptide did not improve the sensitivity or specificity of the RIBA. Although 20% of the patients in our study whose sera reacted to all of the antigens were HCV RNA negative, the positive predictive value of a RIBA considered positive by the manufacturer (two or more bands), was rather high (78%) and may allow suspicion of viremia in EIA2 enzyme-linked immunosorbent assay-positive patients.

Alanine Transaminase↗
PubMed1993

Enzyme-linked oligosorbent assay for detection of polymerase chain reaction-amplified human immunodeficiency virus type 1.

An enzyme-linked oligosorbent assay (ELOSA) was developed for the detection on microtiter plates of polymerase chain reaction (PCR)-amplified human immunodeficiency virus type 1 (HIV-1) DNA. The denatured PCR product was hybridized with a passively adsorbed oligonucleotide capture probe and a horseradish peroxidase-labeled oligonucleotide detection probe. The sensitivity and specificity of the PCR-ELOSA technique depended to some extent on the nucleotide sequences of the oligonucleotide primer and probe quartet used in the amplification and detection. We evaluated five oligonucleotide quartets located in the gag, pol, vpr, env, and nef regions of HIV-1. DNAs from 39 HIV-1-seropositive individuals and 27 healthy HIV-1-seronegative controls were amplified by the PCR procedure, and the products were detected by ELOSA. Ten copies of HIV-1 DNA against a background of 1 microgram of human DNA were specifically detected by PCR-ELOSA. Specificities and sensitivities were, respectively, 100 and 95% for the gag system, 100 and 97% for the pol system, 100 and 85% for the vpr system, 96 and 95% for the env system, and 100 and 95% for the nef system. The simplicity of ELOSA makes it suitable for automation and applicable to genetic testing and detection of viral and bacterial DNAs or RNAs in most routine laboratories.

Base Sequence↗
PubMed1993

Discrimination between human T-cell lymphotropic virus type I and II (HTLV-I and HTLV-II) infections by using synthetic peptides representing an immunodominant region of the core protein (p19) of HTLV-I and HTLV-II.

We describe enzyme immunoassays that use synthetic oligopeptides to discriminate serologically between human T-cell lymphotropic virus type I and II (HTLV-I and HTLV-II) infections. The peptides represented 20-amino acid segments between residues 111 and 130 (MA1) and residues 116 and 135 (MA2) of the p19 gag proteins of HTLV-I and HTLV-II, respectively. The assays were sensitive since 69 of 74 HTLV-positive sera were reactive to at least one of the two matrix (MA) peptides (sensitivity, 93.2%). By using the ratio of the optical density of MA1 to the optical density of MA2, which represents for every serum sample the ratio between the absorbance value obtained in the MA1 assay and the absorbance value obtained in the MA2 assay, 59 of the 69 reactive serum samples were clearly and easily typed as positive for either antibody to HTLV-I or antibody to HTLV-II. Eight of the 10 remaining reactive serum samples were analyzed further by an inhibition procedure, and their type specificities were then clearly identifiable. Therefore, the results indicate that all MA-reactive sera were serologically distinguished by our peptide assays.

Amino Acid Sequence↗
PubMed1993

Prevalence and persistence of antibody titers to recombinant HIV-1 core and matrix proteins in HIV-1 infection.

Numerous studies have established the correlation between antibodies to the core protein p24 of HIV-1 and the progression of the acquired immunodeficiency syndrome. In this study, we analyzed the immune response to two recombinant gag proteins, p24 and p17, in order to evaluate their diagnostic or prognostic significance. Immune response to the immunodominant domain of the transmembrane glycoprotein gp41 was used as a reference. Sera collected from individuals from France and Burundi (Central Africa) at various CDC stages of HIV-1 infection were tested using three sandwich enzyme-linked immunoassays developed with a synthetic peptide corresponding to the immunodominant domain of gp41, SP gp41, or recombinant p24 and p17 cloned and expressed in Escherichia coli. These assays allowed detection of titer antibodies to the three cited antigens. Antibodies to SP gp41 were detected in every HIV-1-positive patient from France and Burundi, generally at a high and stable level. Results obtained with p24 confirmed the value of antibodies to p24 as a prognostic marker only in European and North American populations, since the African population had very high levels of these antibodies even at an advanced stage of the disease. They also confirmed that initial antibody response to p24 is more predictive of outcome than antibody titer change over time. Although antibodies to p17 decline during progression to AIDS, they are frequently absent in French patients at early, asymptomatic stages and therefore could not be used as a prognostic marker. In contrast, antibodies to p17 are significantly less common in African patients with AIDS when compared with symptomless HIV-1-infected African individuals.(ABSTRACT TRUNCATED AT 250 WORDS)

Acquired Immunodeficiency Syndrome↗
PubMed1992

Thymic abnormalities in fetuses aborted from human immunodeficiency virus type 1 seropositive women.

Pathological abnormalities of the thymus were found in 3 of 37 fetuses aborted from human immunodeficiency virus (HIV)-infected mothers. These lesions were located predominantly in the thymic cortex, which contains mostly immature lymphocytes. Areas of focal lymphocyte depletion were infiltrated with CD4+ macrophages and were associated with abnormalities of the epithelial stromal network. No evidence of extensive HIV infection in any of the 37 thymuses was detected by either immunofluorescence or in situ hybridization techniques, although rare cells that expressed HIV antigens were found in 3 fetuses. Although less extensive, this thymic fetopathy was similar to that described in postnatal acquired immunodeficiency syndrome thymuses, strongly suggesting that the lesions were related to HIV infection. Thymic fetopathy might represent the initial injury to the lymphoid system in HIV-infected infants in whom early and severe immunosuppression develops.

Abortion, Induced↗
PubMed1991

[Epidemiologic study of anti-HTLV-I/II antibodies in blood donors in metropolitan France. The Retrovirus Working Group of the National Blood Transfusion Society].

Between march and april 1989, the prevalence of HTLV-I/II antibodies was studied in a non selected population of 45,033 blood donors of Continental France. Serum samples were collected and screened by 12 Blood Banks located in different parts of the country. Screening was performed by 4 ELISAs (Abbott-Du Pont de Nemours-Organon-Pharmacia) and by gelatin particle agglutination (Fujirebio); the sensitivity of these tests was previously evaluated with an HTLV-I/II panel of the French National Society of Transfusion. The reproducibly reactive sera were confirmed by Western-Blot (Du Pont) and radioimmunoprecipitation assay. Five donors were confirmed positive: the global prevalence is 0.011%. This prevalence is one of the highest in Europe. Three of the five positive donors (0.007%) are white subjects. The other two are natives from the French West Indies (0.81%). Since may 1989 the Ministry of Health recommends for Continental France to test donors originating from endemic zones or to use their plasma for fractionation. The results obtained in this study show that the efficacy of these measures are incomplete since 0.007% donors (1 out of 15,000 blood donations) are not tracked down.

Blood Donors↗
PubMed1991

Frequent and early in utero HIV-1 infection.

We have investigated in utero human immunodeficiency virus type 1 (HIV-1) transmission by analyzing human fetal tissues for the presence of viral DNA by means of the polymerase chain reaction (PCR). Thirty three fetal samples: thymus, spleen, and peripheral mononuclear blood cells (PMBC) were obtained at abortion (16 to 24 weeks) from HIV-1-infected asymptomatic women. The results of HIV-1-DNA detection were considered only in 9 cases where contamination of fetal samples by infected mother cells could be definitely eliminated by using primers specific for a polymorphic cellular locus. PCR allowed the identification of HIV-1 DNA sequences in 6/8, 8/9, and 5/9 of specimens from thymus, spleen, and PMBC, respectively. Positive results were shown in fetuses as early as 16 weeks. Viral cultures as well as assays for serum p24 HIV-1 antigen were negative in 9.9 and 33/33 tested, respectively. Therefore, our results indicate early and frequent in utero HIV-1 infection. Different patterns of viral activation after birth might then lead to either rapid or delayed onset of acquired immunodeficiency syndrome.

Base Sequence↗