Characterization of the classical biological false-positive reaction in the serological test for syphilis in the modern era.

To characterize the CBFP reaction in the modern era, we analyzed the results of parallel rapid plasma reagin (RPR) and Treponema pallidum particle agglutination (TPPA) tests from a total of 63,765 blood samples obtained at Zhongshan Hospital in the Medical College of Xiamen University from May 2008 to February 2013. Among the 63,765 tested blood samples, 206 (0.32%) had the CBFP reaction. In multivariate analysis, an increased likelihood of the CBFP reaction was associated with female subjects, subjects ≥80years old, and subjects between 16 and 35years old (P<0.05). The CBFP reaction occurred in association with 17 categories of disease, including 60 types of diseases, in the 206 subjects. To our knowledge, a number of these diseases had not been previously reported to be associated with the CBFP in the RPR test, including false labor, megaloblastic anemias, aplastic anemias, redundant prepuce, congenital malformation of heart, and salpingitis. Among the 206 patients with the CBFP reaction, 35 patients were subjected to follow-up for five years. 26 out of 35 these patients were at a 1:1 initial RPR titer, 8 out of 35 patients were at a 1:2 initial RPR titer, and 1 out of 35 patients were at a 1:4 initial RPR titer. 30 subjects had their RPR seroreverted. In our opinion, additional CBFP research using a large sample population will contribute to the identification of additional underlying serious disorders that are not related to syphilis. Such results could be useful for the prediction and diagnosis of these diseases.

Dual specific antitumor effects of Semliki Forest virus-based DNA vector carrying suicide Escherichia coli purine nucleoside phosphorylase gene via Salmonella.

The Escherichia coli purine nucleoside phospho-rylase/2-fluoro-2-deoxyadenosine (ePNP/F-dAdo) suicide system has demonstrated a powerful killing and bystander effects on tumor cells. However, several drawbacks to this approach remain to be resolved, such as the side-effects and the low efficiency of ePNP-targeted expression. A human telo-merase reverse transcriptase promoter-driven Semliki Forest virus-based DNA vector (pShT-ePNP) with high expression of the ePNP gene was constructed. Live attenuated Salmonella typhimurium 7207 (SL7207) was used initially as a vehicle to targetly transfer the large alphavirus vector into tumor cells. The in vitro quantitative analysis showed ~2-fold higher green fluorescent protein (GFP) expression for pShT-GFP than for conventional cytomegalovirus (CMV) promoter-mediated eukaryotic expression plasmids such as pIRES-GFP and the targeted expression of the ePNP gene in tumor cells was also detected by RT-PCR. After F-dAdo addition, the enzymatic conversion of F-Ado into 2-fluoroadmine (F-Ade) was tested by HPLC. Cell cytotoxicity assays showed that the significant inhibitory effect of the SL/pShT-ePNP system on tumor cells was dose- and time-dependent. Following oral administration, recombinant bacteria targetly allocated within the solid tumor and the expression of ePNP and GFP genes in vivo were detected by RT-PCR or observed by fluorescence microscopy. SL/pShT-ePNP and F-dAdo were also found to exert powerful therapeutic effects in combination against tumor growth and for prolonging the lifespan of tumor-bearing mice. These findings suggest that the SL/pShT-ePNP system may serve as a powerful strategy for tumor therapy.