To investigate a possible influence of GB virus C (GBV-C) in immunocompromised patients, the prevalences of GBV-C RNA and anti-E2 antibody in 197 human immunodeficiency virus (HIV)-infected patients and in 120 control blood donors were studied. GBV-C RNA was detected in 33 of 197 HIV-infected patients (16.8%) compared with 1 in 120 blood donors (0.8%) (P < .001). Previous exposure to GBV-C (anti-E2 antibody-positive) was shown in 56.8% of HIV patients and in 9% of blood donors. GBV-C viremia was not associated with hepatitis. Despite approximately equal duration of HIV infection in all subgroups, the CD4 cell counts were significantly higher in GBV-C-viremic patients (344 cells/microL) compared with exposed (259 cells/microL) and unexposed (170 cells/microL) patients (P = .017 and P < .001). Furthermore, Kaplan-Meier analysis demonstrated significantly better cumulative survival in GBV-C RNA-positive HIV-infected patients, suggesting that GBV-C might be a favorable prognostic factor in HIV disease.

The oxidation of ferric cytochrome c peroxidase by hydrogen peroxide yields a product, compound ES [Yonetani, T., Schleyer, H., Chance, B., & Ehrenberg, A. (1967) in Hemes and Hemoproteins (Chance, B., Estabrook, R. W., & Yonetani, T., Eds.) p 293, Academic Press, New York], containing an oxyferryl heme and a protein free radical [Dolphin, D., Forman, A., Borg, D. C., Fajer, J., & Felton, R. H. (1971) Proc. Natl. Acad. Sci. U.S.A. 68, 614-618]. The same oxidant takes the ferrous form of the enzyme to a stable Fe(IV) peroxidase [Ho, P. S., Hoffman, B. M., Kang, C. H., & Margoliash, E. (1983) J. Biol. Chem. 258, 4356-4363]. It is 1 equiv more highly oxidized than the ferric protein, contains the oxyferryl heme, but leaves the radical site unoxidized. Addition of sodium fluoride to Fe(IV) peroxidase gives a product with an optical spectrum similar to that of the fluoride complex of the ferric enzyme. However, reductive titration and electron paramagnetic resonance (EPR) data demonstrate that the oxidizing equivalent has not been lost but rather transferred to the radical site. The EPR spectrum for the radical species in the presence of Fe(III) heme is identical with that of compound ES, indicating that the unusual characteristics of the radical EPR signal do not result from coupling to the heme site. By stopped-flow measurements, the oxidizing equivalent transfer process between heme and radical site is first order, with a rate constant of 0.115 s-1 at room temperature, which is independent of either ligand or protein concentration.(ABSTRACT TRUNCATED AT 250 WORDS)

Exposure to GBV-C can commence at an early age, although ongoing exposure may also occur among adults with no apparent risk factors. GBV-C RNA positivity was not associated with abnormal plasma alanine aminotransferase levels among blood donors.

The respiratory pathogen Chlamydia pneumoniae has been reported to be associated with respiratory disease, atherosclerosis, and other chronic diseases, originally by serological testing and more recently by the use of nucleic acid amplification (NAA) tests performed on several types of clinical specimens (3,4,11,20). Reports from different laboratories have yielded conflicting results, such as a lack of interlaboratory consensus with regard to PCR results, poor correlation between PCR and serology, and a large range in laboratory results for the diseases mentioned above, which are of real concern to the scientific community (6). To date 19 in-house PCR assays have been published (6). A major outer membrane protein (MOMP)-based, single-step PCR that could identify Chlamydia trachomatis, Chlamydia psittaci, and C. pneumoniae by using three primer pairs and restriction enzyme digestion was originally developed (8). Subsequently, a single-step protocol for C. pneumoniae that amplified a conserved genus-specific target of the chlamydial MOMP gene, followed by restriction enzyme digestion and species identification, was developed (19). A MOMP-based C. pneumoniae PCR with species-specific differentiation, performed by hybridization of the amplified PCR products to internal probes, was also developed (22). The MOMP-based nested PCR described by Tong and Sillis (23) has been more widely employed than the others, since it has proved to be both more sensitive and more specific than other C. pneumoniae diagnostic methods. Another target for PCR amplification of C. pneumoniae has been the 16S rRNA gene (7). This is a single-step PCR with detection by enzyme immunoassay after hybridization to a biotinylated RNA probe, complementary to a fragment of the amplified 16S rRNA gene. The assay has been further developed into a nested format (2, 17, 26) and has also been multiplexed (13, 16). Another frequently used PCR for detection of C. pneumoniae DNA was derived from a cloned 474-bp C. pneumoniae-specific PstI fragment targeted by the HL and HR primers and the HM probe in a nonnested format (5) which has been modified and nested (9, 12). Other amplification targets for C. pneumoniae DNA detection are genes coding for 25) and 53-kDa (10) proteins.Current approaches to help interpret variable findings in clinical studies using PCR assays for C. pneumoniae have focused on standardizing the PCR protocols, including choice of target genes, primers, PCR conditions, detection systems, and nucleic acid extraction techniques (1,14). It has been recognized that a commercially produced PCR assay might enable standardization of C. pneumoniae PCR results. To test the agreement or variability of different assays produced, five laboratories in North America, experienced in conducting PCR assays for C. pneumoniae, participated in this study. They donated positive and negative clinical specimens which were propagated, titrated, and used to create panels of coded specimens. The panel specimens were first DNA extracted and then sent to the particip...

Background: Detection of circulating tumor cells (CTC) in the blood of cancer patients may have prognostic and predictive significance. However, background expression of 'tumor specific markers' in peripheral blood mononuclear cells (PBMC) may confound these studies. The goal of this study was to identify the origin of Cytokeratin 19 (CK19) and HER-2 signal in PBMC and suggest an approach to enhance techniques involved in detection of CTC in breast cancer patients.

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CTCs can be used as predictors of relapse after definitive treatment of locally advanced breast cancer; however, CTCs detection in peripheral blood during the course of PC does not implicate a particular pattern of response to treatment.

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