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Biomedical subjects

R A Gutierrez

Publications and source records attributed to R A Gutierrez.

6 recordsLinked to original sources
PubMed1991

IgM-antibody response to hepatitis C virus antigens in acute and chronic post-transfusion non-A, non-B hepatitis.

A specific IgM solid-phase enzyme-linked immunoassay for the diagnosis of a recent infection by hepatitis C virus (HCV) was developed. The assay utilizes a structural antigen encoded by sequences at the 5' end of HCV (core region) and non-structural (NS) antigens encoded by the NS-3 (33c) and NS-4 (c100-3) regions of the HCV genome. Serial serum samples from several clinically diagnosed post-transfusion non-A, non-B hepatitis patients were analyzed for anti-HCV IgM. This antibody was frequently but transiently detected. Anti-HCV core IgM was more frequently detected than anti-c100-3 or anti-33c IgM. In individuals who resolved their HCV infection or progressed to chronicity, anti-HCV IgM was produced transiently at or near the onset of clinically diagnosed acute hepatitis.

Acute Disease↗
PubMed1991

Detection of antibodies to hepatitis C virus in U.S. blood donors.

An enzyme immunoassay (EIA) which utilizes a solid phase coated with a recombinant antigen (c100-3) derived from the hepatitis C virus (HCV) genome was evaluated for efficacy in the detection of antibodies to HCV (anti-HCV). The sensitivity of the antibody test was demonstrated by the detection of anti-HCV in a well-characterized panel of human specimens known to contain the infectious agent of non-A, non-B hepatitis. The specificity of the anti-HCV test was evaluated by testing 6,118 serum specimens from volunteer blood donors considered to be at low risk for exposure to HCV. The specificity of the anti-HCV EIA was demonstrated to be 99.56%, since 6,069 of 6,096 specimens from this low-risk group were nonreactive. A total of 49 (0.80%) of the 6,118 specimens were repeatedly reactive in the test, and 22 (46.81%) of the 47 specimens available for additional testing were confirmed as positive for antibodies to HCV c100-3. Among commercial plasma donors, 390 (10.49%) of 3,718 specimens were repeatedly reactive in the EIA. A total of 375 (97.40%) of the 385 specimens available for further testing were confirmed as positive. These limited data indicate that the prevalence of antibodies to HCV is 0.36% (22 confirmed positives among 6,118 specimens) among volunteer blood donors and 10.08% (375 confirmed positives among 3,718 specimens) among commercial plasma donors. The importance of confirmatory testing is discussed.

Amino Acid Sequence↗
PubMed1991

Antibodies to recombinant and synthetic peptides derived from the hepatitis C virus genome in long-term-studied patients with posttransfusion hepatitis C.

Eight of 13 Swedish patients (62%), studied prospectively, who developed posttransfusion non-A, non-B hepatitis (PT-NANBH) had earlier been found to seroconvert for antibodies to hepatitis C virus (anti-HCV) c100-3 in the first-generation anti-HCV enzyme-linked immunosorbent assay 1-18 (mean, 8) weeks after onset of hepatitis. By using a second-generation test utilizing antigens encoded by the core NS3 and NS4 region of HCV, a further four patients non-reactive to c100-3 (NS4) were found to seroconvert. Thus 12 of 13 (92%) Swedish patients with PT-NANBH were shown to have HCV infection. In addition, the serologic reactivity for several individual synthetic peptides and/or recombinant HCV proteins was studied in seven anti-HCV c100-3 seroconverts studied long-term after onset of acute PT-HCV infection. No special patterns were found that could differentiate patients who recovered from those who developed chronic HCV infection. It was concluded that the addition of new recombinant antigens derived from the core and NS3 region to c100-3 (NS4) both improved the sensitivity of the anti-HCV test and shortened the window phase to seroconversion.

Alanine Transaminase↗
PubMed1988

Reliable detection of individuals seropositive for the human immunodeficiency virus (HIV) by competitive immunoassays using Escherichia coli-expressed HIV structural proteins.

We molecularly cloned the gag and env genes of the human immunodeficiency virus (HIV) and expressed fragments of these genes in Escherichia coli. Using the recombinant core and envelope proteins, we developed two competitive immunoassays (CIAs). Samples that recognized either the envelope or core proteins were considered positive for antibodies to HIV. This test system was comparable with western blot in detecting antibodies in patients with AIDS or AIDS-related complex that were repeatably reactive in the HIV screening test. All 360 individuals who were positive by western blot were positive by the CIA. A total of 844 samples repeatably reactive by an ELISA screening test were negative both by western blot and by the CIA; 48 samples positive by ELISA, but negative or indeterminate by western blot, were positive by the CIA. Alternate research procedures verified the positivity of these individuals. These data indicate that the CIA described here may be useful as an adjunct or alternative to the western blot.

AIDS-Related Complex↗
PubMedDate not supplied

[Occlusion].

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Dental Occlusion↗