Comparative molecular networking analysis of a Rauwolfia plant powder and biological matrices in a fatal ingestion case

Forensic Toxicology - Identifying xenobiotics involved in deaths remains a challenge in toxicology, especially when they are missing from the usual suspect databases. The tool development for the...     

Application of Hydrogen Peroxide to the Control of Eutrophic Lake Systems in Laboratory Assays

We exposed water samples from a recreational lake dominated by the cyanobacterium Planktothrix agardhii to different concentrations of hydrogen peroxide (H₂O₂). An addition of 0.33 mg·L⁻¹ of H₂O₂ was the lowest effective dose for the decay of chlorophyll-a concentration to half of the original in 14 h with light and 17 h in experiments without light. With 3.33 mg·L⁻¹ of H₂O₂, the values of the chemical oxygen demand (COD) decreased to half at 36 and 126 h in experiments performed with and without light, respectively. With increasing H₂O₂, there is a decrease in the total and faecal coliform, and this effect was made more pronounced by light. Total and faecal coliform were inhibited completely 48 h after addition of 3.33 mg·L⁻¹ H₂O₂. Although the densities of cyanobacterial cells exposed to H₂O₂ did not decrease, transmission electron microscope observation of the trichomes showed several stages of degeneration, and the cells were collapsed after 48 h of 3.33 mg·L⁻¹ of H₂O₂ addition in the presence of light. Our results demonstrate that H₂O₂ could be potentially used in hypertrophic systems because it not only collapses cyanobacterial cells and coliform bacteria but may also reduce chlorophyll-a content and chemical oxygen demand.     

Quercetin induces morphological and proliferative changes of rat’s uteri under estrogen and progesterone influences

This study investigated the effect of 10 or 100 mg/kg/day quercetin on the uterus of ovariectomized adult female rats receiving sex-steroid replacement regime mimicking changes in hormonal profiles during the reproductive cycle. Following seven days of treatment with estrogen and progesterone with or without quercetin, uteri were harvested for histological and proliferative cell nuclear antigen (PCNA) protein and mRNA expression and PCNA protein distribution analyses. Our findings indicated that co-administration of 10 mg/kg/day quercetin with estrogen and progesterone caused a significant decrease in the size of uterine lumen and epithelial heights with lower PCNA protein and mRNA expression as compared to estrogen plus progesterone-only treatment (P < 0.05). Concomitant treatment with estrogen and progesterone with 100 mg/kg/day quercetin resulted in a marked increase in the number of glands with increased PCNA protein and mRNA expression. Significantly higher PCNA distribution was observed in the stroma and glands as compared to estrogen plus progesterone-only treatment (P < 0.05). In conclusion, at 10 mg/kg/day, quercetin affects uterine morphology but not proliferation, however at 100 mg/kg/day, quercetin induced significant stromal and glandular proliferation which could predispose the uterus towards neoplastic development.     

Recent advances in biological nanopores for nanopore sequencing,sensing and comparison of functional variations in MspA mutants

Biological nanopores are revolutionizing human health by the great myriad of detection and diagnostic skills. Their nano-confined area and ingenious shape are suitable to investigate a diverse range of molecules that were difficult to identify with the previous techniques. Additionally, high throughput and label-free detection of target analytes instigated the exploration of new bacterial channel proteins such as Fragaceatoxin C (FraC), Cytolysin A (ClyA), Ferric hydroxamate uptake component A (FhuA) and Curli specific gene G (CsgG) along with the former ones, like α-hemolysin (αHL), Mycobacterium smegmatis porin A (MspA), aerolysin, bacteriophage phi 29 and Outer membrane porin G (OmpG). Herein, we discuss some well-known biological nanopores but emphasize on MspA and compare the effects of site-directed mutagenesis on the detection ability of its mutants in view of the surface charge distribution, voltage threshold and pore–analyte interaction. We also discuss illustrious and latest advances in biological nanopores for past 2–3 years due to limited space. Last but not the least, we elucidate our perspective for selecting a biological nanopore and propose some future directions to design a customized nanopore that would be suitable for DNA sequencing and sensing of other nontrivial molecules in question.

Future of nanopore DNA sequencing: schematic illustration shows the future of nanopore DNA sequencing by using a customized biological nanopore with appropriate fabrication.     

The Ca2+-gated channel TMEM16A amplifies capillary pericyte contraction and reduces cerebral blood flow after ischemia

Pericyte-mediated capillary constriction decreases cerebral blood flow in stroke after an occluded artery is unblocked. The determinants of pericyte tone are poorly understood. We show that a small rise in cytoplasmic Ca²⁺ concentration ([Ca²⁺]_i) in pericytes activated chloride efflux through the Ca²⁺-gated anion channel TMEM16A, thus depolarizing the cell and opening voltage-gated calcium channels. This mechanism strongly amplified the pericyte [Ca²⁺]_i rise and capillary constriction evoked by contractile agonists and ischemia. In a rodent stroke model, TMEM16A inhibition slowed the ischemia-evoked pericyte [Ca²⁺]_i rise, capillary constriction, and pericyte death; reduced neutrophil stalling; and improved cerebrovascular reperfusion. Genetic analysis implicated altered TMEM16A expression in poor patient recovery from ischemic stroke. Thus, pericyte TMEM16A is a crucial regulator of cerebral capillary function and a potential therapeutic target for stroke and possibly other disorders of impaired microvascular flow, such as Alzheimer’s disease and vascular dementia.     

Percepciones estudiantiles sobre las propiedades del examen clínico objetivo estructurado en Uruguay. Disponiendo un cuestionario válido para analizar la factibilidad del nuevo formato durante la transición curricular

Introduction

Although an objective structured clinical examination (OSCE) format has been applied in Uruguay since 2004, and providing reliable performance measures, perceptions of it properties and level of student satisfaction have not been determined.