Evaluation of assays for nucleic acid testing for the prevention of chikungunya and dengue virus transmission by blood transfusion.

BACKGROUND: The large dengue (DENV) and chikungunya (CHIKV) outbreaks observed during the last decade across the world, as well as local transmissions in non-endemic areas are a growing concern for blood safety. The aim of this study was to evaluate and compare the sensitivity of nucleic acid tests (NAT) detecting DENV and CHIKV RNA. MATERIALS AND METHODS: Using DENV 1 to 4 International Standards, the limits of detection (LODs) calculated by probit analysis of two NAT assays; the cobas CHIKV/DENV assay (Roche Diagnostics) and the Procleix Dengue Virus Assay (Grifols) were compared. In addition, CHIKV-RNA LOD of the cobas CHIKV/DENV assay was evaluated. RESULTS: For dengue, the 95% LOD of the cobas assay ranged between 4.10 [CI95%: 2.70-8.19] IU/mL (DENV-2) and 7.07 [CI95%: 4.34-14.89] IU/mL (DENV-4), and between 2.19 [CI95%: 1.53-3.83] IU/mL (DENV-3) and 5.84 [CI95%: 3.84-10.77] IU/mL (DENV-1) for Procleix assay. The Procleix assay had a significant lower LOD for DENV-3 (2.19 vs. 5.89 IU/mL) when compared to the cobas assay (p = 0.005). The 95% LOD for CHIKV-RNA detection of the cobas assay was 4.76 [CI95%: 3.08-8.94] IU/mL. DISCUSSION: The two NAT assays developed for blood donor screening evaluated in this study demonstrated high and similar analytical performance. Subject to an appropriate risk-benefit assessment, they can be used to support blood safety during outbreaks in endemic areas or in non-endemic areas as an alternative to deferring blood donors during local transmission likely to affect the blood supply. The development of multiplex assays is expected to optimize laboratory organization.

Altered toxicological endpoints in humans from common quaternary ammonium compound disinfectant exposure.

Humans are frequently exposed to Quaternary Ammonium Compounds (QACs). QACs are ubiquitously used in medical settings, restaurants, and homes as cleaners and disinfectants. Despite their prevalence, nothing is known about the health effects associated with chronic low-level exposure. Chronic QAC toxicity, only recently identified in mice, resulted in developmental, reproductive, and immune dysfunction. Cell based studies indicate increased inflammation, decreased mitochondrial function, and disruption of cholesterol synthesis. If these findings translate to human toxicity, multiple physiological processes could be affected. This study tested whether QAC concentrations could be detected in the blood of 43 human volunteers, and whether QAC concentrations influenced markers of inflammation, mitochondrial function, and cholesterol synthesis. QAC concentrations were detected in 80 % of study participants. Blood QACs were associated with increase in inflammatory cytokines, decreased mitochondrial function, and disruption of cholesterol homeostasis in a dose dependent manner. This is the first study to measure QACs in human blood, and also the first to demonstrate statistically significant relationships between blood QAC and meaningful health related biomarkers. Additionally, the results are timely in light of the increased QAC disinfectant exposure occurring due to the SARS-CoV-2 pandemic. MAIN FINDINGS: This study found that 80 % of study participants contained QACs in their blood; and that markers of inflammation, mitochondrial function, and sterol homeostasis varied with blood QAC concentration.

Exclusion of Estrogenic and Androgenic Steroid Hormones from Municipal Membrane Bioreactor Wastewater Using UF/NF/RO Membranes for Water Reuse Application.

In the context of water scarcity, domestic secondary effluent reuse may be an option as a reliable source for alleviating acute water shortage. The increasing risks linked with the presence of natural steroid hormones and many emerging anthropogenic micropollutants (MPs) passing through municipal wastewater treatment works (MWWTWs) are of concern for their endocrine-disrupting activities. In this study, domestic wastewater treated by a full-scale membrane bioreactor (MBR) at an MWWTW in the Western Cape Province, South Africa, was used directly as the influent to a reverse osmosis (RO) pilot plant for the removal of selected natural steroid hormones 17ß-estradiol (E2) and testosterone (T) as a potential indirect water recycling application. Estrogenicity and androgenicity were assessed using the enzyme-linked immunosorbent assays (ELISA) and the recombinant yeast estrogen receptor binding assays (YES). The influent pH and flux did not influence the rejection of E2 and T, which was most likely due to adsorption, size exclusion, and diffusion simultaneously. RO and nanofiltration (NF) exhibited excellent removal rates (>95%) for E2 and T. All the E2 effluent samples with MBR/ultrafiltration (UF), MBR/NF, and MBR/RO were lower than the US EPA and WHO trigger value of 0.7 ng/L, as well as the predicted no-effect concentration (PNEC) values for fish (1 ng E2/L).

Detection of BRAF mutations from solid tumors using Tumorplex™ technology.

Allele specific multiplex sequencing (Tumorplex™) is a new molecular platform for the detection of single base mutation in tumor biopsies with high sensitivity for clinical testing. Tumorplex™ is a novel modification of Sanger sequencing technology that generates both mutant and wild type nucleotide sequences simultaneously in the same electropherogram. The molecular weight of the two sequencing primers are different such that the two sequences generated are separated, thus eliminating possible suppression of mutant signal by the more abundant wild type signal. Tumorplex™ platform technology was tested using BRAF mutation V600E. These studies were performed with cloned BRAF mutations and genomic DNA extracted from tumor cells carrying 50% mutant allele. The lower limit of detection for BRAF V600E was found to be 20 genome equivalents (GE) using genomic DNA extracted from mutation specific cell lines. Sensitivity of the assay was tested by challenging the mutant allele with wild type allele at 20 GE, and was able to detect BRAF mutant signal at a GE ration of 20:1 × 10(7) (mutant to wild-type). This level of sensitivity can detect low abundance of clonal mutations in tumor biopsies and eliminate the need for cell enrichment. •Tumorplex™ is a single tube assay that permits the recognition of mutant allele without suppression by wildtype signal.•Tumorplex™ provides a high level of sensitivity.•Tumorplex™ can be used with small sample size with mixed population of cells carrying heterogeneous gDNA.

Diagnostic accuracy of sensitive or high-sensitive troponin on presentation for myocardial infarction: a meta-analysis and systematic review.

BACKGROUND: Recently, high-sensitive troponin (hsTrop) assays consistent with professional societies' recommendations became available. We aimed to summarize the evidence on the diagnostic accuracy of hsTrop on presentation. METHODS: We searched electronic databases for studies evaluating the diagnostic accuracy of hsTrop in suspected acute coronary syndrome (ACS) patients. Random effect meta-analyses and meta-regression were performed. Primary and secondary analyses were restricted to studies using conventional Trop and hsTrop in the reference standard, respectively. RESULTS: Fifteen studies with a total of 8,628 patients met the inclusion criteria for the primary analysis. hsTrop T (Hoffman-La Roche Ltd) and hsTrop I (Siemens) had sensitivities of 0.89 (95% confidence interval [CI]: 0.86-0.91) and 0.90 (95% CI: 0.87-0.92) and specificities of 0.79 (95% CI: 0.77-0.80) and 0.89 (95% CI: 0.87-0.90), respectively. There was no statistically significant difference in the area under the curve between hsTrop (95% CI: 0.920) and conventional Trop (95% CI: 0.929) at the 99th percentile (P=0.62). hsTrop at the level of detection had a sensitivity of 0.97 (95% CI: 0.96-0.98) and a specificity of 0.41 (95% CI: 0.40-0.42). The studies using a cut-off at coefficient of variance <10% as opposed to the 99th percentile for the conventional assay used for diagnosis reported higher diagnostic accuracy (relative diagnostic odds ratio =2.13, P=0.02). Five studies were included in the secondary analysis; hsTrop T (Hoffman-La Roche Ltd) had a sensitivity of 0.91 (95% CI: 0.89-0.93) and a specificity of 0.67 (95% CI: 0.63-0.70). There was significant heterogeneity among the studies. CONCLUSION: hsTrop have excellent diagnostic accuracy for myocardial infarction on presentation, but may not outperform conventional Trop assays. The variation among the studies can be explained, in part, by the cut-off used for conventional Trop assays.