Apical and mechanistic effects of 6PPD-quinone on different life-stages of the fathead minnow (Pimephales promelas).

N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine-quinone (6PPD-quinone) is an emerging contaminant of concern that is generated through the environmental oxidation of the rubber tire anti-degradant 6PPD. Since the initial report of 6PPD-quinone being the cause of urban runoff mortality syndrome of Coho salmon, numerous species have been identified as either sensitive or insensitive to acute lethality caused by 6PPD-quinone. In sensitive species, acute lethality might be caused by uncoupling of mitochondrial respiration in gills. However, little is known about effects of 6PPD-quinone on insensitive species. Here we demonstrate that embryos of fathead minnows (Pimephales promelas) are insensitive to exposure to concentrations as great as 39.97 µg/L for 168 h, and adult fathead minnows are insensitive to exposure to concentrations as great as 9.4 µg/L for 96 h. A multi-omics approach using a targeted transcriptomics array, (EcoToxChips), and proton nuclear magnetic resonance (1H NMR) was used to assess responses of the transcriptomes and metabolomes of gills and livers from adult fathead minnows exposed to 6PPD-quinone for 96 h to begin to identify sublethal effects of 6PPD-quinone. There was little agreement between results of the EcoToxChip and metabolomics analyses, likely because genes present on the EcoToxChip were not representative of pathways suggested to be perturbed by metabolomic analysis. Changes in abundances of transcripts and metabolites in livers and gills suggest that disruption of one­carbon metabolism and induction of oxidative stress might be occurring in gills and livers, but that tissues differ in their sensitivity or responsiveness to 6PPD-quinone. Overall, several pathways impacted by 6PPD-quinone were identified as candidates for future studies of potential sublethal effects of this chemical.

A Multi-Life Stage Comparison of Silver Nanoparticle Toxicity on the Early Development of Three Canadian Fish Species.

Information on the effects of silver nanoparticles (AgNPs) in fish has mostly been generated from standard laboratory species and short-term toxicity tests. However, there is significant uncertainty regarding AgNP toxicity to native species of concern in North America, particularly in northern freshwater ecosystems. We assessed the chronic toxicity of AgNPs in early life stages of three North American fish species: rainbow trout (Oncorhynchus mykiss), lake trout (Salvelinus namaycush), and northern pike (Esox lucius). Newly fertilized embryos were exposed to nominal aqueous concentrations of 0.1, 0.3, 1.0, 3.0, 10.0, or 30.0 nM AgNPs for 126 (rainbow trout), 210 (lake trout), and 25 (northern pike) days. Endpoints included cumulative developmental time (°C × day or degree-days to 50% life-stage transition), mortality, fork length, embryonic malformations, cumulative survival, and histopathology of gill and liver in larvae/alevins. The results showed life stage-specific differences in responses, with endpoints during the embryonic stage occurring more often and at lower concentrations compared to larval/alevin and juvenile stages. Sensitivities among species were highly dependent on the endpoints measured, although developmental time appeared to be the most consistent endpoint across species. At embryonic and larval/alevin stages, northern pike was the most sensitive species (lowest observable effect concentration of 0.1 nM using developmental time). Rainbow trout displayed similar responses to lake trout across multiple endpoints and therefore seems to be an adequate surrogate for trout species in ecotoxicology studies. Moreover, while mortality during individual life stages was not generally affected, the cumulative mortality across life stages was significantly affected, which highlights the importance of chronic, multi-life-stage studies. Environ Toxicol Chem 2021;40:3337-3350. © 2021 SETAC.

Structural MRI at 7T reveals amygdala nuclei and hippocampal subfield volumetric association with Major Depressive Disorder symptom severity.

Subcortical volumetric changes in major depressive disorder (MDD) have been purported to underlie depressive symptomology, however, the evidence to date remains inconsistent. Here, we investigated limbic volumes in MDD, utilizing high-resolution structural images to allow segmentation of the hippocampus and amygdala into their constituent substructures. Twenty-four MDD patients and twenty matched controls underwent structural MRI at 7T field strength. All participants completed the Montgomery-Asberg Depression Rating Scale (MADRS) to quantify depressive symptomology. For the MDD group, volumes of the amygdala right lateral nucleus (p = 0.05, r2 = 0.24), left cortical nucleus (p = 0.032, r2 = 0.35), left accessory basal nucleus (p = 0.04, r2 = 0.28) and bilateral corticoamygdaloid transition area (right hemisphere p = 0.032, r2 = 0.38, left hemisphere p = 0.032, r2 = 0.35) each displayed significant negative associations with MDD severity. The bilateral centrocortical (right hemisphere p = 0.032, r2 = 0.31, left hemisphere p = 0.032, r2 = 0.32) and right basolateral complexes (p = 0.05, r2 = 0.24) also displayed significant negative relationships with depressive symptoms. Using high-field strength MRI, we report the novel finding that MDD severity is consistently negatively associated with amygdala nuclei, linking volumetric reductions with worsening depressive symptoms.

Investigation of quaternary ammonium silane-coated sand filter for the removal of bacteria and viruses from drinking water.

AIMS: To develop an anti-microbial filter media using an attached quaternary ammonium compound (QAC) and evaluate its performance under conditions relevant to household drinking water treatment in developing countries. METHODS AND RESULTS: Silica sand was coated with dimethyloctadecyl [3-(trimethoxysilyl) propyl] ammonium chloride via covalent silane chemistry. Filter columns packed with coated media were challenged with micro-organisms under different water quality conditions. The anti-bacterial properties were investigated by visualizing Escherichia coli (E. coli) attachment to coated media under fluorescence microscopy combined with a live/dead stain. A 9-cm columns with a filtration velocity of 18 m h(-1) achieved log(10) removals of 1·7 for E. coli, 1·8 for MS2 coliphage, 1·9 for Poliovirus type 3 and 0·36 for Adenovirus type 2, compared to 0·1-0·3 log(10) removals of E. coli and MS2 by uncoated sand. Removal scaled linearly with column length and decreased with increasing ionic strength, flow velocity, filtration time and humic acid presence. Escherichia coli attached to QAC-coated sand were observed to be membrane-permeable, providing evidence of inactivation. CONCLUSIONS: Filtration with QAC-coated sand provided higher removal of bacteria and viruses than filtration with uncoated sand. However, major limitations included rapid fouling by micro-organisms and natural organic matter and low removal of viruses PRD1 and Adenovirus 2. SIGNIFICANCE AND IMPACT OF THE STUDY: QAC-coated media may be promising for household water treatment. However, more research is needed on long-term performance, options to reduce fouling and inactivation mechanisms.

Management of proximal femoral fractures 2011: Association of Anaesthetists of Great Britain and Ireland.

There should be protocol-driven, fast-track admission of patients with hip fractures through the emergency department. Patients with hip fractures require multidisciplinary care, led by orthogeriatricians. Surgery is the best analgesic for hip fractures. Surgical repair of hip fractures should occur within 48 hours of hospital admission. Surgery and anaesthesia must be undertaken by appropriately experienced surgeons and anaesthetists. There must be high-quality communication between clinicians and allied health professionals. Early mobilisation is a key part of the management of patients with hip fractures. Pre-operative management should include consideration of planning for discharge from hospital. Measures should be taken to prevent secondary falls. 10. Continuous audit and targeted research is required in order to inform and improve the management of patients with hip fracture.

Biomedicine. New insights into type 2 diabetes.

Researchers studying type 2 diabetes are optimistic that they are closing in on the elusive causes of the world's most prevalent metabolic disorder--although no one is willing to bet the bank on it. Using both biochemical and genetic approaches, diabetes researchers have identified multiple intracellular signaling pathways that appear to lie at the heart of this condition, which affects some 250 million people worldwide and is the leading cause of blindness, kidney failure, and amputation among adults. And in the process, they have thrown out much of the dogma of the past 10 years.