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Biomedical subjects

M P Busch

Publications and source records attributed to M P Busch.

At least 181 records · Page 10Linked to original sources

Monitoring blood donors for HIV-2 infection by testing anti-HIV-1 reactive sera.

Anti-HIV-1 EIA tests currently used for screening blood donors in the United States are estimated to detect 55 to 91% of HIV-2 infections; Western blots for HIV-1 antibodies may be positive, negative or indeterminate with HIV-2-positive sera. We reasoned that we could exploit the cross-reactivity of the anti-HIV-1 EIA as a means to monitor the blood supply for the appearance of HIV-2 infected or co-infected persons, and thus decide if and when routine HIV-2 screening should be adopted. We tested 913 anti-HIV-1-reactive donor sera using an anti-HIV-2 screening EIA, with confirmation by an anti-HIV-2 env-peptide EIA and an anti-HIV-2 Western blot. These 913 sera were derived from anti-HIV-1 screening of approximately 242,000 donations over a three year period. No HIV-2 infections were identified. This approach may warrant adoption in blood centers serving populations with persons from countries where HIV-2 is prevalent.

Antigens, Viral↗

Effects of room-temperature exposure on bacterial growth in stored red cells.

Experiments were performed to determine the effect of room-temperature (RT) exposure on the growth rates of selected bacteria by deliberate contamination of AS-1 packed red cell (RBC) units contained in PL146 plastic bags. Isolates of Staphylococcus aureus, S. epidermidis, Streptococcus faecalis, Pseudomonas aeruginosa, Citrobacter freundii, Enterobacter agglomerans, and Yersinia enterocolitica were inoculated into 3- to 5-day-old packed RBC units. The units were refrigerated at 4 to 6 degrees C for 14 days. On two occasions during this period, one-half of the units were removed from the refrigerator and held at 25 to 26 degrees C for 2 hours. Timed samples taken during the periods at RT revealed stable or decreasing bacterial counts in the majority of exposed units, and in no instance was a marked increase in bacterial growth observed. Samples taken after subsequent prolonged rerefrigeration showed no significant increase in bacterial counts as compared with those in control units that were refrigerated constantly. These results indicate that RT exposure of contaminated RBC units does not result in accelerated bacterial proliferation over a period of 2 hours and that it may, in fact, have a detrimental effect on bacterial growth.

Bacteria↗

Persistent immune complexes and abnormal CD4/CD8 ratios in HIV infection.

We assessed the immunopathologic role of circulating immune complexes in human immunodeficiency virus infection by evaluating the data base and the serum bank of the San Francisco Men's Health Study, a longitudinal clinical and epidemiological investigation conducted since 1983. A group of 4,276 sera from 1,023 (including 811 homosexual/bisexual) men were tested for circulating immune complexes. We used a modification of the commercially available enzyme immunoassay test, based on monoclonal anti-C1q antibodies coupled to the solid phase, for capturing circulating immune complexes from the test serum, followed by detection of circulating immune complexes with either anti-IgG or with anti-IgM probes. Although persistent IgM and IgG circulating immune complexes were most frequently encountered in human immunodeficiency virus-seropositive homosexual/bisexual men, they were not an indicator of disease progression as assessed by abnormalities in the absolute numbers or ratios of CD4- and CD8-positive T cells, or clinical signs and symptoms of AIDS/ARC.

Acquired Immunodeficiency Syndrome↗

Early detection of antibodies against rDNA-produced HIV proteins with a flow cytometric assay.

There is evidence that some human immunodeficiency virus (HIV)-infected individuals have prolonged periods of seronegativity. A flow cytometric immunoreactive bead (IRB) assay is described for quantitative, simultaneous, and early detection of antibodies to HIV. Polystyrene beads of four diameters, each size coated with a different HIV recombinant DNA-produced protein (p24, p31, gp41, or gp120), bound anti-HIV antibodies detected with fluorescent antiglobulin. The IRB assay was performed on a panel of blood donor samples, many giving consistently false-positive enzyme immunoassay (EIA) and indeterminant Western blot (WB) results. The IRB assay proved as sensitive and more specific than currently licensed EIA and WB tests. Results on serial samples from eight HIV-infected individuals indicated that quantitation of anti-p24 by IRB assay may be useful in monitoring disease progression. Sequential pre- and post-EIA seroconversion sera from 35 HIV-infected homosexual men were tested by the IRB assay using IgM- and IgG-specific fluorescent probes. All 35 cases were IRB assay positive for at least one rDNA-p either before (17 of 35, 49%) or at the time of EIA positivity. Eleven cases (31%) initially had only IgM anti-HIV, primarily to gp41 (17%). In two individuals, the IgM response was detected at least 18 months before EIA seroconversion. The IRB assay is a widely applicable analytic procedure, potentially useful in pretransfusion anti-HIV screening of blood.

Flow Cytometry↗

Human immunodeficiency virus seroprevalence among blood product recipients in San Francisco before transfusion.

To determine the incidence of transfusion-associated human immunodeficiency virus (HIV) infection after routine screening of donated blood, a pilot study estimated the pretransfusion prevalence of HIV infection among blood product recipients in San Francisco. Among the 911 nonduplicate pretransfusion specimens from recipients without a clinical history of acquired immune deficiency syndrome (AIDS) or AIDS-related complex (ARC), the overall prevalence of antibody to HIV was 2.9 percent (5.2% among males and 0.6% among females; p = 0.00002). If recipients in specifically defined or possible high-risk groups (n = 348) were excluded, a seropositivity rate of 1.8 percent (10/563) was detected, with all the positives occurring in men (10/242, 4.1%) and none in women (0/321, 0%). This demonstrated prevalence of HIV infection among blood product recipients in San Francisco before transfusion was substantially higher than the known 0.02 to 0.04 percent prevalence in the donor population. Therefore, the population of women without known risk for AIDS is the best in which to assess the risk of HIV infection in patients who are currently receiving seronegative blood transfusions.

Adolescent↗

Reduction of human immunodeficiency virus-infected cells from donor blood by leukocyte filtration.

Several filters for leukocyte removal were evaluated in terms of their ability to reduce the cell-associated human immunodeficiency virus (HIV) load in units of blood either inoculated in vitro with lymphocytes from a chronically infected cell line or collected directly from seropositive donors. Filtration of the experimentally inoculated units of blood resulted in a 5.9 log 10 mean reduction (95% confidence interval:7.4-4.5) of tissue culture infectious units (TCIU) as assayed by end-point titration using the coculture assay. Filtration of the units of blood from anti-HIV positive donors lowered the infectivity by over 2 logs, as detected by the coculture and polymerase chain reaction (PCR) techniques. However, residual cell-associated virus was detected in the majority of experiments. Clinical studies are warranted to determine if leukocyte filtration of blood will reduce the risk of transfusion transmitted viral infections.

Acquired Immunodeficiency Syndrome↗

Assessment of human immunodeficiency virus expression in cocultures of peripheral blood mononuclear cells from healthy seropositive subjects.

We have evaluated a number of methodological variables effecting the expression of human immunodeficiency virus (HIV) in cultured peripheral blood mononuclear cells (PBMCs) of 93 healthy anti-HIV-positive and 72 healthy seronegative subjects. For optimal HIV recovery, PBMCs had to be freshly separated from whole blood. Short-term freezing of purified PBMCs was practically advantageous and actually resulted in more rapid virus recovery. The minimal number of PBMCs necessary for virus expression was determined by dilutional cultures and varied from 10(2) to 10(6) cells. HIV expression was demonstrated initially at the cellular level by immunocytochemical detection of HIV core and envelope proteins using a mixture of monoclonal antibodies, subsequently confirmed by detection of viral antigens and reverse transcriptase (RT) in the culture supernatants. HIV recovery was not improved following induction with 5-iodo-2'-deoxyuridine (IUDR) and only marginally improved following depletion of the CD8+-suppressor cell population in the PBMC specimens. The overall frequency of HIV detection in cultures was 84% in healthy seropositive subjects, whereas none of the PBMCs from 72 seronegative persons yielded HIV expression.

Cells, Cultured↗

Transcription and replication of human immunodeficiency virus-1 in B lymphocytes in vitro.

We and others have shown that HIV-1 transcription and replication in vitro are increased by the binding of transcriptional enhancer DNA sequences in the HIV-1 long terminal repeat (LTR) to a cellular protein designated Nuclear Factor-kappa B (NF-kappa B), a trans-acting transcription factor which is present in activated but not in resting T cells. Because NF-kappa B is also expressed in resting B cells we suggested that B cells might provide an optimal intracellular environment for HIV-1 transcription. Using a transient transfection assay, we show that the HIV-1 LTR is indeed more efficiently transcribed in the B cell line Raji than in the T cell line Jurkat, and that this effect maps to the transcriptional enhancer (NF-kappa B binding site) of the LTR. Furthermore, we show that Raji cells which have been rendered CD4-positive by gene transfection are susceptible to HIV-1 infection, and that viral gene expression and replication are more efficient in these CD4-positive B cells than in CD4-positive T cells. These findings demonstrate the crucial role of the transcriptional enhancer in regulating HIV-1 expression and, since receptors for HIV-1 are expressed by some Epstein-Barr virus (EBV)-positive B cells, they also suggest that HIV-1 replication could occur in EBV-positive B cells in vivo.

Antigens, Differentiation, T-Lymphocyte↗

In situ hybridization and immunocytochemistry for improved assessment of human immunodeficiency virus cultures.

The authors characterized the early intracellular events involved in human immunodeficiency virus (HIV) replication after in vitro inoculation into cultures of susceptible human T-cell lines and phytohemagglutinin-stimulated peripheral-blood mononuclear cells (PMCs). Within 24 hours of infection, in situ hybridization with HIV DNA probe detected cytoplasmic viral RNA. Viral core antigen was detected in infected cells over the subsequent two to ten days by means of an immunocytochemical assay employing monoclonal antibodies. Several days later, cell-free virus was detected by both reverse transcriptase assay and a p25gag antigen-capture assay. When these methods were applied to monitor cultures of ten sero-positive persons' PMCs, a similar progression of virus replication was apparent: cytoplasmic viral RNA was detected in infected PMCs by day 3, with the subsequent appearance of intracellular viral proteins (days 6-9) and cell-free virus (days 12-21). In situ hybridization and immunocytochemistry offer complementary, sensitive, and specific approaches for monitoring the early stages of acquired immune deficiency syndrome virus replication in vitro.

Acquired Immunodeficiency Syndrome↗

Finnish En(a-) propositus with anti-EnaFS and anti-EnaFR: in vitro and in vivo characteristics.

A third Finnish En(a-) individual (ERP) with alloanti-Ena has been identified. Subsequent family studies revealed that ERP is distantly related to the 2 previous Finnish En(a-) propositi. Serologically, ERP's erythrocytes were found to be M-N-'N'+S-s+U+En(a-)Wr(a-b-) and were sialic acid deficient. SDS-PAGE studies confirmed that the red cell membranes lacked the MN-sialoglycoprotein, glycophorin-A. ERP's serum contained an IgG antibody which demonstrated two separable specificities, a ficin-sensitive specificity (anti-EnFS) and a ficin-resistant specificity (anti-EnFR), which reacted by the indirect antiglobulin technique. The antibodies were probably pregnancy induced, as ERP had never been transfused. A 51Cr-labelled red cell survival study showed that the antibodies were capable of causing significant destruction of incompatible red cells.

Antibody Specificity↗

Interaction of aflatoxin and hepatitis B virus in the pathogenesis of hepatocellular carcinoma.

Aflatoxin-B1 (AFB) and chronic hepatitis B virus (HBV) infection epidemiologically correlate with the geographic distribution of hepatocellular carcinoma (HCC). Integration of HBV DNA into the cellular genome of HCCs and the in vivo formation of adducts between AFB and nucleic acids lead us to suggest that hepatocytes with integrated HBV DNA preferentially accumulate AFB; the AFB-adducts formed may then initiate cell transformation by modifying the expression of critical host genes. The altered molecular biology of liver cells in HCC is evidenced by the fact that HBV does not replicate in HCC tissues or cell lines. The effect of AFB on the expression of cellular genes such as endogenous retrovirus(es) and possibly cellular oncogene(s) can be analyzed in HCC cell lines with and without integrated HBV DNA. In addition, human HCC tissues can be probed for HBV sequences and AFB-DNA adducts at the single-cell level. The presence of HBV and AFB can be correlated with the expression of putative transforming genes, providing a new insight into the interaction between liver cells, HBV and AFB in the pathogenesis of HCC.

Aflatoxin B1↗

Chronic renal failure: a significant risk factor in the development of acquired renal cysts and renal cell carcinoma. Case reports and review of the literature.

Three male patients with end-stage renal disease on chronic hemodialysis presented with gross hematuria and were subsequently found to have acquired renal cyst disease and progressive bilateral renal cell carcinoma. There are now more than 84 similar cases in the literature, but the precise roles that renal failure and hemodialysis play in the development of renal cysts and renal neoplasms remain unclear. The high incidence of acquired renal cyst disease (45%) and the development of renal tumors (9%, with a 5% to 7% metastatic rate) in patients with end-stage renal failure clearly underscores the need for more intense radiologic monitoring.

Adult↗

Hepatorenal syndrome complicating chronic lymphocytic leukemia.

Hepatorenal syndrome and portal hypertension developed in a 59-year-old man with chronic lymphocytic leukemia. At autopsy, he had portal hypertension from lymphocytic infiltration of the liver with compression of the portal veins, and no other pathologic process in the liver. Histologic examination of the kidney did not reveal a lesion that could account for the observed renal insufficiency. This case report documents the association of a lymphoproliferative disorder with portal hypertension and hepatorenal syndrome.

Humans↗

Evaluation of the indirect immunofluorescence assay as a confirmatory test for detecting antibodies to the human immunodeficiency virus.

One hundred and eighty-four serum specimens were assayed for antibodies to the human immunodeficiency virus. All specimens were screened with a commercial enzyme immunoassay and confirmed by two indirect immunofluorescence assays. Sera were also assayed by Western blot. Results from sera of 48 healthy heterosexual volunteers were all negative by EIA, IFA, and Western blot. Sera from 50 healthy homosexual men negative by EIA were also negative by IFA and Western blot. Sixty-two patients with persistent generalized lymphadenopathy or newly diagnosed AIDS all were positive by EIA, IFA, and Western blot. Of 24 sera from patients with autoantibodies, with no evidence of AIDS-related diseases, five appeared to be false-positive by EIA, since they were nonreactive by IFA and Western blot. In addition, three other samples contained both autoantibodies and human immunodeficiency virus antibodies. False-positive results were observed in both the EIA and IFA with monoclonal antibodies directed toward the MHC class II antigens DQ and DR. The reactivity of these antibodies could not be distinguished from positive patients' sera, in either EIA or IFA. We conclude that in general indirect immunofluorescence performed well as a confirmatory test after screening by enzyme immunoassay for human immunodeficiency virus antibodies.

Antibodies, Viral↗