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Biomedical subjects

M P Busch

Publications and source records attributed to M P Busch.

At least 145 records · Page 8Linked to original sources
PubMed1994

Heterosexual transmission of human immunodeficiency virus type 1 from transfusion recipients to their sex partners.

Using lookback procedures and other methods, we identified and then prospectively followed human immunodeficiency virus type 1 (HIV-1)-infected transfusion recipients and their sex partners to determine AIDS incidence and risks of heterosexual transmission of HIV-1. At enrollment, 7 of 32 (21.9%) female partners of male recipients were themselves infected with HIV-1, as compared with none of 14 male partners of female recipients (p = 0.08). No additional episodes of transmission were observed. The prevalence of advanced immunodeficiency at enrollment was similar in male and female recipients. Male recipients with advanced immunodeficiency (CD4+ lymphocyte count < or = 0.20 x 10(9)/L or a history of clinical AIDS) at enrollment were more likely to have infected their female partners (odds ratio = 7.9; p = 0.03) than men with neither condition. Similarly, AIDS-free survival, as estimated by the product-limit method, was lower among male transmitters than among male nontransmitters (p = 0.01). Transmission was not associated with frequency of unprotected vaginal intercourse. Our data suggest that HIV-1-infected men who develop immunodeficiency rapidly are more likely to infect their sex partners and that the greater efficiency of male-to-female HIV-1 transmission is not explained by a greater number of sexual contacts or more advanced immunodeficiency in index subjects.

Adult↗
PubMed1994

Transfusion and HIV.

Over a decade has passed since the first cases of AIDS were reported in hemophiliacs and transfusion recipients. Studies published over the past year offer an increasingly clear understanding of the extent of the early transfusion-associated AIDS epidemic, and of the effectiveness of progressive donor screening measures in safeguarding the blood supply from HIV. Although a number of recent studies have confirmed that the residual risk of HIV infection from blood and blood components is very small, effort continues toward development of new screening tests and viral inactivation procedures. Deciding whether these procedures warrant implementation will be a major challenge in the upcoming years.

Blood Donors↗
PubMed1993

A pattern of 5-1-1 and c100-3 only on hepatitis C virus (HCV) recombinant immunoblot assay does not reflect HCV infection in blood donors.

Current criteria for a reactive (positive) interpretation on hepatitis C virus (HCV) recombinant immunoblot assay (RIBA) require > or = 1+ reactivity to at least two of the four HCV antigens present in the assay. Given that 5-1-1 is a subcomponent of c100-3, there is concern that donor samples reacting only with these two antigens (and not with c22-3 or c33c) could be incorrectly classified as positive on the basis of limited reactivity to only one HCV gene product. It is determined that 0.23 to 0.44 percent of HCV enzyme immunoassay-repeatably reactive donor sera demonstrate a pattern of 5-1-1 and c100-3 only on RIBA. Evaluation of six such donor sera using peptide enzyme immunoassays spanning the c100-3 antigen showed highly restricted reactivity to the 5-1-1 N-terminal region of c100-3, in contrast to broad 5-1-1 and c100-3 C-terminal peptide reactivity observed in the majority of donor sera with other positive RIBA patterns. HCV polymerase chain reaction and follow-up serologic evaluations of four of these donors indicated the absence of viremia or evolving seroconversion in all cases. It is concluded that, in the blood donor setting, a pattern of only 5-1-1 and c100-3 reactivity is typically not indicative of HCV infection. To avoid overinterpretation, it is recommended that RIBA grading criteria be revised to require reactivity to two or more HCV-encoded gene products.

Amino Acid Sequence↗
PubMed1993

Rapid freezing of whole blood or buffy coat samples for polymerase chain reaction and cell culture analysis: application to detection of human immunodeficiency virus in blood donor and recipient repositories. The Transfusion Safety Study Group.

Storage of lymphocytes for later use in prospective epidemiologic studies of blood donors and transfusion recipients has been limited by the cost of separating peripheral blood mononuclear cells (PBMCs). When the Transfusion Safety Study began in 1985, it was decided to establish a cell repository of cryopreserved buffy coat (BC) samples, and thus far over 20,000 samples have been accumulated from enrolled subjects. To determine if these specimens could be used for polymerase chain reaction, a simple thawing and pelleting technique for recovering hemoglobin-free total white cells (WBCs) was developed. To validate the technique, parallel analysis was conducted of BCs, whole blood (WB), and PBMC samples from human immunodeficiency virus type 1 (HIV-1)-seropositive subjects. Immediate postthaw cell courts of 29 frozen-thawed (F-T) WB and BC samples averaged 90 percent of the prefreeze (input) values. Representative WBC populations were obtained by immediate pelleting. Amplification of HIV-1 gag sequences from F-T BCs and F-T WB was 94 and 75 percent, respectively, which is as sensitive as that obtained with freshly separated PBMC lysates. Quantitative HIV-1 proviral load analysis by serial dilution of 23 F-T BCs and 8 WB lysates showed results comparable to those obtained with lysates of fresh PBMCs. Values for WBC differential and immunophenotyping could be applied to express viral load relative to total WBCs, PBMCs, or CD4+ cells. These results establish the basis for simplified virologic analysis of cryopreserved BC or WB specimens.

Blood Donors↗
PubMed1993

Determination of human T lymphotropic virus type by polymerase chain reaction and correlation with risk factors in northern California blood donors.

To determine the relative prevalence of human T lymphotropic virus (HTLV) types I and II, type-specific polymerase chain reaction (PCR) was done on seropositive northern California blood donors. From October 1988 through March 1990, 67 (0.055%) of 122,517 blood donors had confirmed HTLV antibody. Seropositive donors were more likely to be middle-aged, female, and nonwhite than the overall donor base. PCR of samples from 30 HTLV-seropositive donors yielded 19 (63%) with HTLV-II and 9 (30%) with HTLV-I; 2 (7%) were repeatedly negative by PCR. HTLV-I-infected subjects had ancestry (n = 3), sexual contact (n = 3), or paternal military service in (n = 1) Japan or the Caribbean. HTLV-II carriers reported past intravenous drug abuse (n = 3) or sex with a drug user (n = 11). Two carriers of each type reported previous blood transfusions, and 1 HTLV-II carrier was a dentist with no other risk factors for retroviral infection.

Adult↗
PubMed1993

HIV-1 PCR and isolation in seroconverting and seronegative homosexual men: absence of long-term immunosilent infection.

The presence of detectable HIV-1 prior to the appearance of HIV-1-specific antibody was assessed in 41 incident infections that occurred during a 6-year prospective cohort study. All available antibody-negative samples (n = 138) and the first antibody positive sample (n = 41) were tested, under code, by the polymerase chain reaction (PCR) in two laboratories and by HIV-1 isolation in a third laboratory. Samples were available as long as 66 months and at least 18 months before seroconversion for 24/41 subjects. An equal number of time-matched control specimens from persistently seronegative homosexual men and 103 samples from normal blood donors were also tested under code. Samples with discordant results were subjected to coded repeat analysis along with appropriate controls. All but one of the 41 first antibody-positive specimens (97.6%) were PCR positive and 65% were isolation positive. Two control specimens from seronegative homosexual men were PCR positive and one was culture positive, but HLA typing provided clear evidence of specimen mix-up in the specimen archive. For 37/41 seroconvertors, all available antibody negative specimens were negative by both PCR and virus isolation. In three cases, the specimen obtained 6 months before seroconversion was PCR and isolation positive. One specimen, obtained 12 months before SC, was PCR positive and isolation negative but was determined to be the result of sample contamination. Both PCR and isolation were negative in this subject 6 months before SC. In conclusion, we were unable to detect immunosilent infection > 6 months before seroconversion in high-risk homosexual men.

Adult↗
PubMed1993

Analysis of hepatitis C virus RNA prevalence and surrogate markers of infection among seropositive voluntary blood donors.

A novel reverse transcription polymerase chain reaction assay has been developed that uses drop-in-drop-out primers for the heminested amplification of hepatitis C virus complementary DNA. This assay has been used for analysis of the prevalence of hepatitis C virus RNA in a set of 53 plasma specimens from blood donations that were repeatedly reactive for hepatitis C virus antibodies with the first-generation enzyme immunoassay. Of 21 specimens that were also reactive for hepatitis C virus antibodies by a four-antigen recombinant immunoblot assay (recombinant immunoblot assay 2), 20 (95%) contained detectable levels of hepatitis C virus RNA. Cryoprecipitate in three specimens reactive in the recombinant immunoblot assay led to an apparent failure of detecting hepatitis C virus RNA, but repeat tests of redissolved cryoprecipitate subsequently revealed hepatitis C virus RNA. Hepatitis C virus RNA was also detected in plasma from 5 of 29 donors nonreactive by recombinant immunoblot assay. However, evidence of viremia in these donors could not be confirmed on follow-up specimens collected more than 1 yr later. Our results demonstrate that the presence of recombinant immunoblot assay reactivity nearly always indicates hepatitis C viremia and suggest that viremia may be transient or fluctuating among some individuals who are nonreactive for hepatitis C virus antibodies by the recombinant immunoblot assay.

Algorithms↗
PubMed1992

Allogeneic leukocytes but not therapeutic blood elements induce reactivation and dissemination of latent human immunodeficiency virus type 1 infection: implications for transfusion support of infected patients.

Various immunologic stimuli and heterologous viral regulatory elements have been shown to increase susceptibility to, and replication of, human immunodeficiency virus type 1 (HIV-1) in lymphocytes and monocytes in vitro. Transfusion of allogeneic blood components from heterologous donors constitutes a profound immunologic stimulus to the recipient, in addition to being a potential route of transmission of lymphotropic viral infections. To investigate the hypothesis that transfusions, and particularly those containing leukocytes, activate HIV-1 replication in infected recipient cells, we cocultured peripheral blood mononuclear cells (PBMC) from three anti-HIV-1-positive individuals with allogeneic donor PBMC, as well as partially purified populations of donor lymphocytes, monocytes, granulocytes, platelets, and red blood cells (RBC) and allogeneic cell-free plasma. Allogeneic PBMC induced a dose-related activation of HIV-1 expression in in vivo infected cells, followed by dissemination of HIV-1 to previously uninfected patient cells. Activation of HIV-1 replication was observed with donor lymphocytes, monocytes, and granulocytes, whereas no effect was seen with leukocyte-depleted RBC, platelets, or plasma (ie, therapeutic blood constituents). Allogeneic donor PBMC were also shown to upregulate HIV-1 expression in a "latently" infected cell line, and to increase susceptibility of heterologous donor PBMC to acute HIV-1 infection. Studies should be performed to evaluate whether transfusions of leukocyte-containing blood components accelerate HIV-1 dissemination and disease progression in vivo. If so, HIV-1-infected patients should be transfused as infrequently as possible and leukocyte-depleted (filtered) blood components should be used to avoid this complication.

Acquired Immunodeficiency Syndrome↗
PubMed1992

False-negative results by polymerase chain reaction due to contamination by glove powder.

The polymerase chain reaction (PCR) technique has become an important, widely employed method for the detection and quantitation of the nucleic acid sequences used in the diagnosis and monitoring of genetic and infectious diseases. Much attention has been directed at the problem of false-positive PCR results, which are generally attributed to low-level laboratory contamination of amplified sequences ("carryover"). In contrast, few investigators have commented on the somewhat less frequent, but equally problematic, false-negative PCR results. Investigation of the source of sporadic false-negative PCR reactions found that glove powder, inadvertently introduced into tubes when gloves are changed in an effort to reduce false-positive results, can nonspecifically inhibit each of the major steps in the PCR detection process. Methodologic precautions are recommended to minimize this problem.

Drug Contamination↗
PubMed1992

Comparative evaluation of supplemental hepatitis C virus antibody test systems.

Implementation of routine blood donor screening using anti-hepatitis C virus (HCV) enzyme immunoassay (EIA) has resulted in an urgent need for well-characterized supplemental assays to confirm the presence of HCV antibodies. A comparative study of four commercially available supplemental assays is reported here: first- and second-generation versions of a strip recombinant immunoblot assay (RIBA-1 and RIBA-2), an HCV neutralization EIA, and HCV neutralization plus synthetic peptide EIA. Three hundred sixty-seven blood donor specimens that were repeatedly reactive on HCV EIA were studied. Most specimens (93%) were also evaluated by radioimmunoassay (RIA) with a six-antigen panel, and 60 selected specimens were tested for HCV RNA by the polymerase chain reaction (PCR). RIBA-1 and RIBA-2 gave concordant results with 86 percent of specimens, while an additional 13 percent were correctly classified by RIBA-2 but not RIBA-1. Neutralization EIA alone correctly identified 94 percent of the study group, while the remaining 6 percent required the peptide EIA or the combined neutralization-peptide assay system for correct classification. The RIBA-2 and neutralization-peptide assay system for correct classification. The RIBA-2 and neutralization-peptide assay systems yielded identical results for 86 percent of specimens, and these results were supported by RIA and selected PCR testing. Only 2 specimens (0.5%) were frankly discrepant, while 51 specimens were indeterminate on either (47) or both (4) assays. When either the RIBA-2 or neutralization-peptide assay yielded an indeterminate interpretation, the other system correctly classified the specimen (based on concordance with RIA and PCR data) in a high proportion (92%) of cases.(ABSTRACT TRUNCATED AT 250 WORDS)

Antibodies, Viral↗
PubMed1992

Impact of specimen handling and storage on detection of hepatitis C virus RNA.

Direct detection of hepatitis C virus (HCV) RNA in serum or plasma is useful for validating the performance of anti-HCV assays and for the discrimination of persons with persistent HCV infections from those with resolved infections. Quantitation of HCV RNA may also be useful for disease prognosis and therapeutic monitoring. Previous studies have reported detection of HCV RNA in 50 to 70 percent of blood donors who were positive on anti-HCV supplemental tests. There is concern that specimen processing and storage conditions might influence the stability, and hence the detectability, of HCV RNA. To address this concern, the rate of detection of HCV RNA by the polymerase chain reaction (PCR) using donor pilot tube sera (PTS) previously subjected to routine donor screening and supplemental testing was compared with HCV PCR results obtained with fresh-frozen plasma (FFP) derived from the same donations. All 16 anti-HCV supplemental test-positive donations evaluated were HCV RNA positive with FFP, whereas only 10 (62.5%) were positive with PTS (p = 0.024). None of 11 FFP or PTS samples from HCV enzyme immunoassay-reactive donations not confirmed by supplemental anti-HCV assays tested positive for HCV RNA. Direct comparison of sample type (serum vs. plasma) and various storage conditions using specimens from two seropositive donors showed that room-temperature storage results in marked reduction in HCV RNA signal, while replicate freezing and thawing caused a moderate reduction. These data indicate that well-controlled sample processing and storage conditions are critical to the sensitive and potentially quantitative analysis of HCV RNA.

Blood Preservation↗