Bioaugmentation of pilot-scale slow sand filters can achieve compliant levels for the micropollutant metaldehyde in a real water matrix.

Metaldehyde is a polar, mobile, low molecular weight pesticide that is challenging to remove from drinking water with current adsorption-based micropollutant treatment technologies. Alternative strategies to remove this and compounds with similar properties are necessary to ensure an adequate supply of safe and regulation-compliant drinking water. Biological removal of metaldehyde below the 0.1 µg•L-1 regulatory concentration was attained in pilot-scale slow sand filters (SSFs) subject to bioaugmentation with metaldehyde-degrading bacteria. To achieve this, a library of degraders was first screened in bench-scale assays for removal at micropollutant concentrations in progressively more challenging conditions, including a mixed microbial community with multiple carbon sources. The best performing strains, A. calcoaceticus E1 and Sphingobium CMET-H, showed removal rates of 0.0012 µg•h-1•107 cells-1 and 0.019 µg•h-1•107 cells-1 at this scale. These candidates were then used as inocula for bioaugmentation of pilot-scale SSFs. Here, removal of metaldehyde by A. calcoaceticus E1, was insufficient to achieve compliant water regardless testing increasing cell concentrations. Quantification of metaldehyde-degrading genes indicated that aggregation and inadequate distribution of the inoculum in the filters were the likely causes of this outcome. Conversely, bioaugmentation with Sphingobium CMET-H enabled sufficient metaldehyde removal to achieve compliance, with undetectable levels in treated water for at least 14 d (volumetric removal: 0.57 µg•L-1•h-1). Bioaugmentation did not affect the background SSF microbial community, and filter function was maintained throughout the trial. Here it has been shown for the first time that bioaugmentation is an efficient strategy to remove the adsorption-resistant pesticide metaldehyde from a real water matrix in upscaled systems. Swift contaminant removal after inoculum addition and persistent activity are two remarkable attributes of this approach that would allow it to effectively manage peaks in metaldehyde concentrations (due to precipitation or increased application) in incoming raw water by matching them with high enough degrading populations. This study provides an example of how stepwise screening of a diverse collection of degraders can lead to successful bioaugmentation and can be used as a template for other problematic adsorption-resistant compounds in drinking water purification.

Diagnostic value of serum fibrinogen as a predictive factor for complicated appendicitis (perforated). A cross-sectional study.

BACKGROUND: Acute appendicitis (AA) has a prevalence of 8% in the general population with a rate of complicated (perforated) appendicitis (CA) up to 40%. Serum fibrinogen may serve as an indicator for CA. PATIENTS AND METHODS: 115 patients were included from January 2012 to December 2012 using a positive pathology report for AA as a gold standard diagnostic method. We divided the patients into two groups accordingly to the pathology report: Complicated Appendicitis and Uncomplicated Appendicitis (UA). Our primary endpoint was to compare the levels of serum fibrinogen between the two groups and find if there is a relationship between fibrinogen level and CA. RESULTS: 68 patients were diagnosed with UA and 47 with CA. Using a fibrinogen value of 885 mg/dl we found to be the best cut-off for predicting complicated appendicitis with a sensitivity of 86.77% (76.87-93.71 IC 95%), a specificity of 91.49 (83.51-99.46 IC 95%), a positive predictive value of 93.65 (95% CI 86.81-99.64) and, a negative predictive value of 82.69 (95% CI 65.73-87.84). CONCLUSION: In the setting of a patient with a clinical diagnosis of AA, this study demonstrates fibrinogen as a good predictor factor for appendiceal perforation.

Effect of ZNF217 gene polymorphisms on colorectal cancer development in a Mexican population.

The ZNF217 gene, a potential oncogene amplified and overexpressed in several cancers including colorectal cancer (CRC), acts as a transcription factor that activates or represses target genes. The polymorphisms rs16998248 (T>A) and rs35720349 (C>T) in coronary artery disease have been associated with reduced expression of ZNF217. In this study, we analyzed the 2 polymorphisms in Mexican patients with CRC. Genotyping of rs16998248 and rs35720349 sites was performed by polymerase chain reaction-restriction fragment length polymorphism in 203 Mexican Mestizos, 101 CRC patients, and 102 healthy blood donors. Although no statistical differences regarding genotype and allele frequencies of ZNF217 polymorphisms were observed (P > 0.05), linkage disequilibrium was significant in CRC patients (r(2) = 0.39, P < 0.0001), as a result of reduced AC haplotype frequency. Thus, the AC haplotype may protect against CRC.