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Biomedical subjects

F B Hollinger

Publications and source records attributed to F B Hollinger.

At least 37 records · Page 2Linked to original sources
PubMed1997

An ELISA for detection of antibodies to the E2 protein of GB virus C.

An ELISA was developed for detection of antibodies to GB virus C (GBV-C) using a recombinant E2 protein expressed in CHO cells. Seroconversion to anti-E2 positivity was noted among several persons infected with GBV-C RNA-positive blood through transfusion. Of 6 blood recipients infected by GBV-C RNA-positive donors, 4 (67%) became anti-E2 positive and cleared their viremia. Thus, anti-E2 seroconversion is associated with viral clearance. The prevalence of antibodies to E2 was relatively low (3.0%-8.1%) in volunteer blood donors but was higher in several other groups, including plasmapheresis donors (34.0%), intravenous drug users (85.2%), and West African subjects (13.3%), all of whom tested negative by GBV-C reverse-transcription polymerase chain reaction (RT-PCR). These data demonstrate that testing for anti-E2 should greatly extend the ability of RT-PCR to define the epidemiology and clinical significance of GBV-C.

Africa↗
PubMed1997

Defining the time of fetal or perinatal acquisition of human immunodeficiency virus type 1 infection on the basis of age at first positive culture. Women and Infants Transmission Study (WITS).

It has been suggested that a positive diagnostic test for human immunodeficiency virus type 1 (HIV-1) during the first 48 h of life is indicative of intrauterine transmission, whereas negative tests during the first week with positive tests later indicate intrapartum transmission. On the basis of data from all 140 infected infants in the Women and Infants Transmission Study (WITS), the probability was estimated that an HIV-1 culture would be positive for the first time at each day of life if cultures were performed daily. The estimated probabilities (+/-SE) by days 0, 2, 4, 7, 9, 16, and 30 of life are 27.4% (+/-6.4%), 27.4% (+/-13.0%), 45.3% (+/-20.5%), 45.3% (+/-22.5%), 65.3% (+/-20.0%), 88.4% (+/-7.8%), and 89.3% (+/-7.0%), respectively. The initial 27% probability is consistent with the hypothesis that transmission usually occurs during the intrapartum period. However, the distribution of age at first positive culture does not separate clearly into two distinct intervals. More definitive methods for determining the timing of transmission are needed.

Age Factors↗
PubMed1997

Improved methods for quantification of human immunodeficiency virus type 1 RNA and hepatitis C virus RNA in blood using spin column technology and chemiluminescent assays of PCR products.

The quantification of human immunodeficiency virus type 1 (HIV-1) RNA or hepatitis C virus (HCV) RNA has been facilitated by adapting a spin column procedure for sample preparation and the use of chemiluminescent detection of polymerase chain reaction (PCR) products in microtiter plate format. All materials were commercially available and relatively inexpensive. By making a single dilution prior to amplification, concentrations of 500 copies to 2.5 million HIV-1 1 RNA copies per mL and 1,000 copies to 50 million HCV RNA copies per mL could be determined on 140-microL samples. Between-run imprecision employing the improved procedure for HIV-1 RNA was 23%. Correlation of HIV-1 RNA concentrations obtained using chemiluminescent detection with values obtained by colorimetric assay of PCR products was 0.98. Correlation of HCV RNA concentration determined by the spin column-chemiluminescent assay procedure with those obtained by branched DNA methodology was 0.91. Spin columns could be used with serum or plasma containing acid-citrate-dextrose or heparin anticoagulant, but heparinized samples required treatment with heparinase prior to amplification.

Anticoagulants↗
PubMed1996

Kernel density analysis of variable and conserved regions of the envelope proteins of human immunodeficiency virus type 1 and associated epitopes.

A new statistical approach to the study of conservation of amino acid and nucleotide sequences based on kernel density analysis is described that enables analysis of both conserved and highly variable HIV-1 protein sequences. The amino acid sequences of HIV-1 env proteins in 63 isolates were analysed to determine, first, whether the designations of regions identified in 1987 as conserved (C1-C6) or variable (V1-V5) were still valid. Even though the data base used was nine times larger, the designations that were based on seven isolates from five patients remain correct. Second, the new approach enabled the quantifications of the degree of conservation in reported B or T cell epitopes. Using this approach, highly conserved epitopes located in both gp41 and gp120 were identified.

Amino Acid Sequence↗
PubMed1996

Donor levels of serum alanine aminotransferase activity and antibody to hepatitis B core antigen associated with recipient hepatitis C and non-B, non-C outcomes.

BACKGROUND: Hepatitis virus(es) that are neither hepatitis B (HBV) nor hepatitis C (HCV) (non-B, non-C [NBNC]) may be transmitted by transfusion. The present study assessed donor values for alanine aminotransferase (ALT) and antibody to hepatitis B core antigen (anti-HBc) for their association with HCV and NBNC hepatitis outcomes among allogeneic blood recipients. STUDY DESIGN AND METHODS: Data on blood donors and recipients enrolled in the Transfusion- Transmitted Viruses Study in four United States cities from 1974 through 1980 were supplemented by anti-HBc testing of donors and anti-HCV evaluation of recipients. Two statistical approaches estimated the value of these indirect tests in detecting donors associated with HCV seroconversion and NBNC hepatitis in recipients. RESULTS: For HCV cases, donor ALT alone (at > or = 60 IU/L) had a sensitivity and a specificity of 30 and 96 percent, respectively, and anti-HBc alone (at > or = 60% inhibition) had a sensitivity and specificity of 53 and 86 percent, respectively. The two markers combined had a sensitivity and a specificity of 69 and 83 percent. For NBNC hepatitis cases, each measure had low sensitivity (20%) that was not improved by using both (28%) [corrected]. CONCLUSION: The indirect tests proved to be equal in sensitivity to the first-generation anti-HCV tests. The positive predictive power of these indirect tests in the 1980s was sufficient to affect HCV incidence in studies during that period. Improved anti-HCV assays, however, replaced the need for indirect tests. The sensitivity of indirect tests for NBNC hepatitis contributed little.

Alanine Transaminase↗
PubMed1996

Application of a commercial kit for detection of PCR products to quantification of human immunodeficiency virus type 1 RNA and proviral DNA.

Quantitative tests for human immunodeficiency virus type 1 (HIV-1) RNA in plasma and proviral DNA in peripheral blood mononuclear cells (PBMC) provide valuable information on the status of HIV-1 infection. This paper describes tests that were carried out with commercially available materials and an enzyme-linked immunosorbent assay reader for detecting spectrophotometric changes. Samples consisted of 100 microliters of plasma or 200,000 PBMC. The procedure involved sample preparation, PCR-based amplification with the primer pair SK39 (biotinylated at the 5' end) and SK38, hybridization of the cDNA PCR product to an RNA probe, capture of the RNA-DNA hybrid on a solid phase by means of strepavidin, binding to an alkaline phosphatase-conjugated antibody directed against RNA-DNA hybrids, and incubation with p-nitrophenylphosphate. Spectrophotometric changes were recorded at four intervals over a period of 20 h. The inclusion of HIV-1 RNA or proviral DNA standards in each run was an integral part of the procedure. The dynamic ranges afforded by these assays--500 to 1 million RNA copies per ml and 10 to 5,000 proviral DNA copies per 10(6) PBMC--were applicable to most plasma specimens and to all PBMC specimens from HIV-1-infected patients. Correlations of log-transformed HIV-1 RNA and proviral DNA concentrations with those found by reference methods were, respectively, 0.88 and 0.80. The between-run coefficients of variation for the detection method were < or = 25% (range, 9.1 to 24.7) and < or = 15% (range, 10.9 to 15.1), respectively, for HIV-1 RNA and proviral DNA. The reproducibility of the overall procedure for HIV-1 RNA in plasma (including sample preparation, amplification, and detection) was given by a duplicate standard deviation of log10 copies per ml of 0.11. Thus, the method was sufficiently precise to allow the detection of fourfold changes in plasma HIV-1 RNA concentrations, with a power of 0.95.

DNA, Viral↗
PubMed1996

Evaluation of an infectivity standard for real-time quality control of human immunodeficiency virus type 1 quantitative micrococulture assays. Participating Laboratories of The AIDS Clinical Trials Group.

Quantitative microculture assays of cryopreserved human immunodeficiency virus type 1-infected cell suspensions and culture supernatants were compared among seven assays sites. There was no significant change in titer during 1 year of storage. The overall standard deviation for infected cell suspensions was approximately 0.8 log10 virus titer. A method for detecting deviant assay results was developed and was used to identify two donor cell preparations (n = 54) that gave consistently low titers.

Cell Culture Techniques↗
PubMed1996

Comprehensive control (or elimination) of hepatitis B virus transmission in the United States.

In the United States, the reported rate of hepatitis B has declined by over 50% since 1987, probably as a result of vaccination programmes, behavioural changes, refinements in blood screening procedures, and the availability of virus inactivated blood components. The majority of new hepatitis B infections occur in 20-39 year olds, and perinatal transmission is uncommon except in certain at risk groups. Initial efforts to control hepatitis B in the US were targeted at high risk groups, including health care personnel. Then, in 1988, the Centers for Disease Control and Prevention (CDC) recommended screening of all pregnant females for hepatitis B surface antigen and full immunisation of infants born to those testing positive. A recommendation for universal immunisation of infants was endorsed in 1991. Compliance has been slow but progressive. The CDC also has recommended 'catch up' immunisation of adolescents and high risk children and adults. Demonstration projects suggest that these can be successful, given the provision of free or low cost vaccine and appropriate support. Hepatitis B vaccination has been shown to be cost effective and should be integrated into the routine childhood immunisation schedule. Responses to hepatitis B vaccine have largely been shown to be durable, although at least one booster dose after five to 10 years seems prudent, especially if a low dose, yeast derived vaccine has been used.

Adolescent↗
PubMed1995

Life span of circulating membrane CD4 inserted into the plasma membranes of autologous red blood cells of HIV-infected subjects.

Membrane recombinant CD4 was electroinserted into the plasma membrane of red blood cells (RBCs) from four HIV patients. CD4 had been labeled with 125I before electroinsertion. The RBCs-CD4-125I were labeled with 51Cr and autotransfused to the donor patients. The hematological indexes and the P50 value of the RBCs were not modified by the electroinsertion of CD4. The life span of the RBCs was not affected by electroinsertion of CD4 (t1/2 approximately 30 days), whereas the exposed CD4 showed a kinetics of disappearance characterized by two half-life times: a short one (t1/2 approximately 1 day) and a long one approximately equal to that of the RBCs. No side effects or anti-CD4 immune responses were observed in patients over a period of 28 days. The RBC-CD4 entity appears to be long-lived and has no adverse effect in HIV patients.

Adult↗
PubMed1995

Donor screening for antibody to hepatitis B core antigen and hepatitis B virus infection in transfusion recipients.

BACKGROUND: Testing for antibody to hepatitis B core antigen (anti-HBc) as a surrogate for hepatitis C viremia is no longer needed for blood donor screening. Currently, the important question is how much its use supplements hepatitis B surface antigen (HBsAg) donor screening in preventing transfusion-transmitted hepatitis B virus (HBV) infection. STUDY DESIGN AND METHODS: In a study conducted in the 1970s, 64 blood donors were associated with 15 cases of HBV (1.0%) in 1533 transfusion recipients. Sera from 61 donors at donation and 29 follow-up visits were available for present-day assays for HBsAg, HBV DNA, anti-HBc, and antibody to HBsAg (anti-HBs). RESULTS: HBsAg was found in four previously negative blood donors; HBV DNA was limited to three of these four. Anti-HBc was detected in six HBsAg-negative donors. Two other donors were negative in all assays at donation, but positive for anti-HBc and anti-HBs 2 to 4 months later. The remaining donors were negative for all HBV markers, which left five recipient cases unexplained. No HBV transmission was observed when anti-HBs sample-to-negative control values were > or = 10. CONCLUSION: Some 33 to 50 percent of cases of hepatitis B that could be transmitted by transfusion of blood from HBsAg-negative donors are prevented by anti-HBc screening. Anti-HBc-positive donors unequivocally positive for anti-HBs should be considered noninfectious for HBV and should be allowed to donate. Anti-HBc screening of paid plasmapheresis donors, supplemented by anti-HBs testing, would reduce the amount of HBV to be processed by virus inactivation and increase the content of anti-HBs in plasma pools.

Blood Donors↗
PubMed1995

Single-strand conformation polymorphism study of human immunodeficiency virus type 1 RNA and DNA in plasma, peripheral blood mononuclear cells, and their virologic cultures.

Single-strand conformation polymorphism (SSCP) analysis was applied to human immunodeficiency virus type 1 (HIV-1) nucleic acids in plasma and peripheral blood mononuclear cells (PBMC) from 16 patients and to 15 PBMC cocultures and 6 plasma cultures prepared from the specimens. Two hypervariable regions were analyzed: in the gag gene and part of the V3 loop. Random paired matching of SSCP patterns between HIV-1 RNA and provirus DNA was tested, from plasma and PBMC from the same blood specimen, supernatant and PBMC from the same PBMC coculture, supernatant and PBMC from the same plasma culture, provirus DNA in cocultured PBMC and the PBMC inoculum, and HIV-1 RNA in a plasma culture supernatant and in the plasma inoculum. Paired matching was nonrandom for both regions in the first three situations and for gag in the fourth, with P < or = .01; matching was random for gag in the last situation. The HIV-1 env target region produced in culture diverged from that in the inoculum in 18 of 21 instances.

Base Sequence↗
PubMed1995

Sensitivity of immune complex-dissociated p24 antigen testing for early detection of human immunodeficiency virus in infants.

Several investigators have suggested that early diagnosis of human immunodeficiency virus (HIV) infection in infants could be accomplished with a modified, more-sensitive, acid-dissociated p24 antigen enzyme-linked immunosorbent assay (ELISA) technique (p24 antigen immune complex dissociation [ICD]). We compared detection of HIV infection by HIV culture, PCR, and p24 antigen ICD assays in 46 infants by using samples collected independently. The detection sensitivity of the p24 antigen ICD assay was 0% with cord blood samples (2 HIV-positive infants), 38% with plasma samples from infants under 3 months of age (8 HIV-positive infants), and 58% overall (12 HIV-positive infants). By contrast, the sensitivities of HIV culture and PCR were 50% for cord blood samples, 75% for plasma samples from infants under 3 months of age, and 83% overall. These results indicate that the p24 antigen ICD does not offer the sensitivity necessary for this assay to be used as an indicator of HIV infection in infants.

Antigen-Antibody Complex↗
PubMed1995

HIV-1 and HHV-6 antigens and transcripts in retinas of patients with AIDS in the absence of human cytomegalovirus.

PURPOSE: The purpose of this study was to define the agents involved in the development of acquired immune deficiency syndrome (AIDS)-associated retinitis. To achieve this goal, the authors determined the frequency and proximity of the simultaneous presence of human immunodeficiency virus (HIV)-1, human herpesvirus (HHV)-6, and human cytomegalovirus (HCMV) in retinas of patients with AIDS with and without AIDS-associated retinitis. METHODS: Retinal sections from 50 globes from patients with AIDS were analyzed for the presence of viral antigens and transcripts. Group 1 contained 13 globes from patients with HCMV infection. Group 2 contained 20 globes from patients with retinal lesions of uncertain etiology in which HCMV antigen and transcripts were not detected. Group 3 contained 17 globes from patients with no retinal lesions. RESULTS: Retinal sections from all 13 globes (group 1) were positive for HCMV antigens and HIV-1 antigens and transcripts. Six of the 13 retinas were also positive for HHV-6 antigens and transcripts. Sections from 13 of the 20 globes (group 2) were positive for HIV-1 antigens and transcripts, and 5 of these 13 were also positive for HHV-6 antigens and transcripts. Multiple areas in sections from two of the HIV-1-positive retinas showed coinfection with HHV-6. All 17 globes (group 3) were positive for HIV-1 antigens and transcripts. Ten of these 17 retinas were also positive for HHV-6 antigens. Human cytomegalovirus antigens were not detectable in retinas from groups 2 and 3. No viral antigens or transcripts were detectable in retinal sections from 10 HIV-1 negative donors. CONCLUSION: The coexistence of HIV-1 and HHV-6 activity in more than 50% of retinas without HCMV infection suggests that HIV-1 and HHV-6 alone or in combination may predispose retinal tissue to other opportunistic agents such as HCMV during the development of AIDS-associated retinitis.

AIDS-Related Opportunistic Infections↗
PubMed1994

Serum p24 antigen level as an intermediate end point in clinical trials of zidovudine in people infected with human immunodeficiency virus type 1. Aids Clinical Trials Group Virology Laboratories.

Serum p24 antigen levels were examined in subjects from three clinical trials of zidovudine to determine whether the pattern of change in serum p24 antigen during the first 8-16 weeks of therapy was associated with human immunodeficiency virus type 1 (HIV-1) disease progression or death. Among 406 patients with AIDS and a first episode of Pneumocystis carinii pneumonia, 65% had measurable pretreatment concentrations of serum p24 antigen (> or = 10 pg/mL). Changes during treatment were not associated with reduced mortality. In 637 mildly symptomatic patients, 24% had measurable concentrations, and changes were marginally associated with increased time until more advanced disease. Among 683 asymptomatic patients, 18% had measurable concentrations, and changes were not associated with increased time until progression. Despite the small number of clinical events and the low rate of serum p24 antigen positivity in the latter two studies, pretreatment serum p24 antigen levels were predictive of clinical outcome; subsequent measurements appear to be of limited use in evaluating zidovudine therapy.

AIDS-Related Complex↗
PubMed1994

Multicenter evaluation of quantification methods for plasma human immunodeficiency virus type 1 RNA.

Six procedures for quantifying plasma human immunodeficiency virus type 1 (HIV-1) RNA were evaluated by nine laboratories. The procedures differed in their sample volume and preparation of samples and methods of amplification and detection. Coded samples in a 10-fold dilution series of HIV-1-spiked plasma were correctly ranked by all six procedures. Subsequently, coded duplicate plasma samples from 16 HIV-1-infected patients were tested using a common set of standards. Several HIV-1 RNA procedures were sufficiently reproducible so that an empiric 4-fold change could be viewed as significant. HIV-1 RNA levels in the patients (up to 370,000 RNA copies/mL) correlated with proviral HIV-1 DNA and were inversely correlated with CD4 cell counts; HIV-1 RNA assays were more sensitive than plasma viremia, standard p24 antigen, or immune complex-dissociated p24 antigen assays. This study demonstrated that several HIV-1 RNA quantitative assays are ready for use in clinical trials.

Acquired Immunodeficiency Syndrome↗
PubMed1994

A comparative study of human immunodeficiency virus culture, polymerase chain reaction and anti-human immunodeficiency virus immunoglobulin A antibody detection in the diagnosis during early infancy of vertically acquired human immunodeficiency virus infection.

The infection status of 91 infants born to mothers with human immunodeficiency virus (HIV) infection was determined. Twenty-eight (31%) infants had confirmed HIV infection and 63 (69%) had seroreverted to HIV and lack evidence of infection. During the first 6 months of life HIV culture had a sensitivity and specificity for diagnosis of HIV infection of 80 and 100%, respectively. False negative HIV cultures were observed in only 7 of 35 specimens, 6 from among the 12 infected infants tested at birth. The sensitivity and specificity of polymerase chain reaction (PCR) detection of HIV were 95 and 93% respectively. A single false negative PCR test result was observed among the 19 tests performed on specimens from HIV-infected infants. False positive PCR test results were observed occasionally throughout the first 6 months of life. Detection of HIV-specific IgA antibody lacked diagnostic sensitivity; positive test results were observed in only 53% of specimens obtained from infected infants. Culture and PCR detection offer excellent sensitivity and specificity for diagnosis of HIV infection during the first 6 months of life; however, false-negative HIV cultures sometimes are observed, particularly during the newborn period, and either false negative or false positive PCR test results may be noted occasionally. For purposes of clinical decision-making, any positive test result should be confirmed with a second HIV culture or PCR test performed on a separate blood specimen.

False Negative Reactions↗
PubMed1994

Dilution assay statistics.

A parametric method of statistical analysis for dilution assays is developed in detail from first principles of probability and statistics. The method is based on a simple product binomial model for the experiment and produces an estimate for the concentration of target entities, a confidence interval for this concentration, and an indicator of the quality of the assay called the p value for goodness of fit. The procedure is illustrated with data from a virologic quantitative micrococulture assay used to quantify free human immunodeficiency virus in clinical trials. The merits of the procedure versus those of nonparametric methods of estimating the dilution inducing a 50% response rate are discussed. Advantages of the proposed approach include plausibility of the underlying assumptions, ability to assess plausibility of specific experimental outcomes through their likelihood, and plausibility of confidence intervals.

Biometry↗