Evaluation of chemiluminescence immunoassay as a screening test for syphilis on blood donor samples.

BACKGROUND AND OBJECTIVE: Global re-emergence of syphilis among blood donors necessitates novel diagnostic and prevention approaches that encourage timely intervention. Thus, the present study was planned to evaluate the efficiency of Chemiluminescence immunoassay (CLIA) as a screening test for syphilis. MATERIAL AND METHODS: This prospective cross-sectional observational study was conducted from October 2021 to September 2022. A total of 344 donors were enrolled by purposive sampling method, including additional 16 donors who were reactive by the Rapid plasma reagin test (RPR) during the study period. Data from three screening tests - RPR test, Treponema pallidum haemagglutination assay (TPHA) and CLIA for 360 blood donors were analysed. TPHA was considered the gold standard test. RESULTS: Of the total 360 samples tested, 21 (5.8 %) were reactive by the RPR test. Of these 21 RPR reactive samples, 19 (90.5 %) were reactive by both TPHA and CLIA, while 2 (9.5 %) RPR reactive samples were non-reactive by both TPHA and CLIA. Of the remaining 339 RPR non-reactive samples, 1 (0.3 %) sample was reactive by both TPHA and CLIA, and 1 (0.3 %) was reactive by CLIA alone. CLIA was found to have sensitivity and specificity of 100 % and 99.7 % and positive predictive value (PPV) and negative predictive values (NPV) of 95.2 % and 100 % respectively, while it was 95 %, 99.4 %, 90 %, and 99.7 %, respectively, with the RPR test. CONCLUSION: CLIA was found to have a higher sensitivity, specificity, PPV and NPV than the RPR test. Thus, CLIA can be an acceptable alternative for syphilis screening in blood donors.

Semiparametric Bayesian estimation of quantile function for breast cancer survival data with cured fraction.

Existing cure-rate survival models are generally not convenient for modeling and estimating the survival quantiles of a patient with specified covariate values. This paper proposes a novel class of cure-rate model, the transform-both-sides cure-rate model (TBSCRM), that can be used to make inferences about both the cure-rate and the survival quantiles. We develop the Bayesian inference about the covariate effects on the cure-rate as well as on the survival quantiles via Markov Chain Monte Carlo (MCMC) tools. We also show that the TBSCRM-based Bayesian method outperforms existing cure-rate models based methods in our simulation studies and in application to the breast cancer survival data from the National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) database.

Effect of nonendocytic uptake of nanoparticles on human bronchial epithelial cells.

The toxicity of artificial nanoparticles is a major concern in industrial applications. Cellular uptake of hard nanoparticles could follow either endocytic or nonendocytic pathways, leading to different stimuli to the cells. Yet the cellular responses to nanoparticles following different pathways have not been compared due to the lack of an independent nonendocytic delivery method. We applied a unique delivery method, nanochannel electroporation (NEP), to produce predominantly nonendocytic uptakes of quantum dots (Q-dots) and multiwalled carbon nanotubes (MWCNTs) with different chemical modifications. NEP delivery bypassed endocytosis by electrophoretic injection of nanoparticles into human bronchial epithelial (BEAS-2B) cells at different dosages. Conventional exposure by direct nanoparticle suspending in cell culture medium was also performed as control. The dosage-dependent responses to nanoparticles under different uptake pathways were compared. Fluorescence colocalization demonstrated that nanoparticles followed both endocytic and nonendocytic pathways for cell entry in contact exposure, whereas NEP delivery of nanoparticles bypassed endocytosis. Nonendocytic entry resulted in much higher oxidation stress and, for MWCNTs, more cell death in BEAS-2B cells. Despite the observation that most nanoparticles were taken up by cells through endocytosis, the minor nonendocytic entry of nanoparticles seemed to dominate the overall cellular response in conventional contact exposure. Our finding suggests that prevention against nonendocytic uptake could help reduce the toxicity of hard nanoparticles.