Impact of Early-Life Exposure to Bisphenol A on Survival and Histopathology of Liver and Kidney of Zebrafish (Danio rerio)

Bisphenol A (BPA) is a highly used chemical and an ubiquitous environmental contaminant in urban aquatic ecosystems. BPA disrupts hormonal and metabolic pathways of living organisms through its endocrine disrupting activity. Early-life BPA exposure could perturb key developmental processes, thus affecting the survival of living organisms. BPA is known to accumulate in water bodies, therefore it is important to understand the impact of BPA on aquatic organisms and ecosystem health. The objective of this study was to investigate the impact of early-life BPA exposure on survival and histology of kidney and liver of zebrafish. Zebrafish model is widely used in environmental monitoring and BPA-related studies. During the study zebrafish were treated for 60 days with two environmentally prevalent concentrations of BPA (1 μg/L and10 μg/L) and with a treatment control. Twenty wild-type juvenile zebrafish of age 35 dpf (days post fertilisation) were assigned to triplicate tanks and were treated until maturity in 95 dpf. Water of the tanks were changed once per three days. Survival percentage of the fish were calculated weekly. The kidney and liver of a sample of five fish from control treatment and 10 μg/L of BPA were obtained at 95 dpf for histopathological study. Kidney and liver sections were stained using heamatoxylin/eosin and examined under light microscope for structural pathology. The highest mean survival of 90% was observed in the control group at the end of the treatment period while, 56.57% and 41.67 % of survival were observed at 1 μg/L and 10 μg/L of BPA treatments respectively. This observation led to the conclusion that BPA has a significant impact on fish survival where high BPA concentrations resulted in significantly low survival. Histopathological analysis of the kidneys of fish treated with 10 μg/L of BPA revealed damaged renal tubules, shrinkage of tubules or tubule lumen, degeneration of tubules and hematopoietic tissue when compared with the control group. The liver histopathology of BPA-treated fish revealed lipid accumulation in hepatocytes. The reduced survival and structural distortion of liver and kidney of zebrafish in BPA-treated tanks could be due to chronic early-life BPA exposure as the quality of water significantlyaffects the fish survival, growth and development. It can be concluded that early-life exposure to environmentally prevalent doses of BPA can result in increased mortality in zebrafish model. This study calls for more comprehensive studies to understand the physiological impact of early-life BPA exposure on aquatic organisms.Keywords: Bisphenol A, Zebrafish, Survival, Histology, Liver, Kidne

Impact of Climate Change on Selected Physiological Parameters of Polypedates Cruciger (Common Hourglass Tree Frog)

Increased temperature and atmospheric CO2 concentration leading to acidification of water bodies are major attributes of climate change. Amphibians are known to be highly-sensitive to climate change. Accordingly, the objective of this study was to determine the chronic physiological responses of Polypedates cruciger to climate change based on continuous exposure to elevated temperature and CO2-induced acidification from early-larval to adult stages. Newly-hatched tadpoles of Polypedates cruciger were allocated to treatment tanks containing de-chlorinated tap water and acclimatized for two weeks. The experimental treatments were two elevated temperatures (E32 and E34), one elevated CO2 treatment (ECO2) treatment and a Control at ambient temperature and CO2. In E32 and E34, water temperatures were elevated up to 32±0.5o C and 34±0.5o C at ambient CO2 to represent predicted warming under Representative Concentration Pathway (RCP) 8.5 (E34) and RCP 2.6 (E32). In ECO2, CO2 in water was elevated to maintain its pH between 5.5 and 5.6±0.1 to represent the range predicted by RCPs 8.5 and 2.6 respectively. Each treatment was triplicated with 15 tadpoles in each. The experiment continued until the tadpoles reached Gosner Stage 42. Mean concentration of ammonia released per individual was (AmRel) was calculated using ammonia concentration of each tank, determined by Phenate method. AmRel of E34 and E32 were not significantly different from the Control. AmRel of ECO2 was significantly higher than the Control during the first two weeks however, the opposite was observed during the rest of experiment. AmRel of all treatments was reduced during metamorphosis and showed weekly variations, with E34 treatment showing the highest variation. Although statistically insignificant, the mean catalase activity was greater in ECO2, while the overall swimming speed was lower in all treatments, compared to control. Lysozyme activity of tadpoles was significantly greater in ECO2 compared to Control. The number of leukocytes in 2000 erythrocytes was significantly different among ECO2, E32 and the Control, with highest and lowest values being recorded from the Control and ECO2 respectively. Deformities (oedema, tail kink, pale pigmentation) were most abundant in E32. Results showed that temperature and CO2 elevations predicted under even the most eco-friendly scenario of RCP2.6 (E32) can affect the physiology of Polypedates cruciger. In conclusion, the abundance of deformities and physiological parameters such as ammonia excretion, swimming activity, catalase enzyme activity and immunity in terms of lysozyme activity and WBC levels of Polypedates cruciger are affected by predicted temperature and CO2 increases attributed to future climate change.Keywords: Elevated temperature and CO2, Reduced pH, Ammonia, Catalase, Lysozym

Lung Recruitment Strategies During High Frequency Oscillatory Ventilation in Preterm Lambs

Background: High frequency oscillatory ventilation (HFOV) is considered a lung protective ventilation mode in preterm infants only if lung volume is optimized. However, whilst a “high lung volume strategy” is advocated for HFOV in preterm infants this strategy is not precisely defined. It is not known to what extent lung recruitment should be pursued to provide lung protection. In this study we aimed to determine the relationship between the magnitude of lung volume optimization and its effect on gas exchange and lung injury in preterm lambs.Methods: 36 surfactant-deficient 124–127 d lambs commenced HFOV immediately following a sustained inflation at birth and were allocated to either (1) no recruitment (low lung volume; LLV), (2) medium- (MLV), or (3) high lung volume (HLV) recruitment strategy. Gas exchange and lung volume changes over time were measured. Lung injury was analyzed by post mortem pressure-volume curves, alveolar protein leakage, gene expression, and histological injury score.Results: More animals in the LLV developed a pneumothorax compared to both recruitment groups. Gas exchange was superior in both recruitment groups compared to LLV. Total lung capacity tended to be lower in the LLV group. Other parameters of lung injury were not different.Conclusions: Lung recruitment during HFOV optimizes gas exchange but has only modest effects on lung injury in a preterm animal model. In the HLV group aiming at a more extensive lung recruitment gas exchange was better without affecting lung injury

An individualized approach to sustained inflation duration at birth improves outcomes in newborn preterm lambs

A sustained first inflation (SI) at birth may aid lung liquid clearance and aeration, but the impact of SI duration relative to the volume-response of the lung is poorly understood. We compared three SI strategies: 1) variable duration defined by attaining volume equilibrium using real-time electrical impedance tomography (EIT; SIplat); 2) 30 s beyond equilibrium (SIlong); 3) short 30-s SI (SI30); and 4) positive pressure ventilation without SI (no-SI) on spatiotemporal aeration and ventilation (EIT), gas exchange, lung mechanics, and regional early markers of injury in preterm lambs. Fifty-nine fetal-instrumented lambs were ventilated for 60 min after applying the allocated first inflation strategy. At study completion molecular and histological markers of lung injury were analyzed. The time to SI volume equilibrium, and resultant volume, were highly variable; mean (SD) 55 (34) s, coefficient of variability 59%. SIplat and SIlong resulted in better lung mechanics, gas exchange and lower ventilator settings than both no-SI and SI30. At 60 min, alveolar-arterial difference in oxygen was a mean (95% confidence interval) 130 (13, 249) higher in SI30 vs. SIlong group (two-way ANOVA). These differences were due to better spatiotemporal aeration and tidal ventilation, although all groups showed redistribution of aeration towards the nondependent lung by 60 min. Histological lung injury scores mirrored spatiotemporal change in aeration and were greatest in SI30 group (P < 0.01, Kruskal-Wallis test). An individualized volume-response approach to SI was effective in optimizing aeration, homogeneous tidal ventilation, and respiratory outcomes, while an inadequate SI duration had no benefit over positive pressure ventilation alone

First insights into the phylogenetic diversity of Mycobacterium tuberculosis in Nepal

BACKGROUND: Tuberculosis (TB) is a major public health problem in Nepal. Strain variation in Mycobacterium tuberculosis may influence the outcome of TB infection and disease. To date, the phylogenetic diversity of M. tuberculosis in Nepal is unknown. METHODS AND FINDINGS: We analyzed 261 M. tuberculosis isolates recovered from pulmonary TB patients recruited between August 2009 and August 2010 in Nepal. M. tuberculosis lineages were determined by single nucleotide polymorphisms (SNP) typing and spoligotyping. Drug resistance was determined by sequencing the hot spot regions of the relevant target genes. Overall, 164 (62.8%) TB patients were new, and 97 (37.2%) were previously treated. Any drug resistance was detected in 50 (19.2%) isolates, and 16 (6.1%) were multidrug-resistant. The most frequent M. tuberculosis lineage was Lineage 3 (CAS/Delhi) with 106 isolates (40.6%), followed by Lineage 2 (East-Asian lineage, includes Beijing genotype) with 84 isolates (32.2%), Lineage 4 (Euro-American lineage) with 41 (15.7%) isolates, and Lineage 1 (Indo-Oceanic lineage) with 30 isolates (11.5%). Based on spoligotyping, we found 45 different spoligotyping patterns that were previously described. The Beijing (83 isolates, 31.8%) and CAS spoligotype (52, 19.9%) were the dominant spoligotypes. A total of 36 (13.8%) isolates could not be assigned to any known spoligotyping pattern. Lineage 2 was associated with female sex (adjusted odds ratio [aOR] 2.58, 95% confidence interval [95% CI] 1.42-4.67, p = 0.002), and any drug resistance (aOR 2.79; 95% CI 1.43-5.45; p = 0.002). We found no evidence for an association of Lineage 2 with age or BCG vaccination status. CONCLUSIONS: We found a large genetic diversity of M. tuberculosis in Nepal with representation of all four major lineages. Lineages 3 and 2 were dominating. Lineage 2 was associated with clinical characteristics. This study fills an important gap on the map of the M. tuberculosis genetic diversity in the Asian reg

Microfold (M) cells: important immunosurveillance posts in the intestinal epithelium

The transcytosis of antigens across the gut epithelium by microfold cells (M cells) is important for the induction of efficient immune responses to some mucosal antigens in Peyer’s patches. Recently, substantial progress has been made in our understanding of the factors that influence the development and function of M cells. This review highlights these important advances, with particular emphasis on: the host genes which control the functional maturation of M cells; how this knowledge has led to the rapid advance in our understanding of M-cell biology in the steady-state and during aging; molecules expressed on M cells which appear to be used as “immunosurveillance” receptors to sample pathogenic microorganisms in the gut; how certain pathogens appear to exploit M cells to infect the host; and finally how this knowledge has been used to specifically target antigens to M cells to attempt to improve the efficacy of mucosal vaccines

Monitoring the newly qualified nurses in Sweden: the Longitudinal Analysis of Nursing Education (LANE) study

BACKGROUND: The Longitudinal Analysis of Nursing Education (LANE) study was initiated in 2002, with the aim of longitudinally examining a wide variety of individual and work-related variables related to psychological and physical health, as well as rates of employee and occupational turnover, and professional development among nursing students in the process of becoming registered nurses and entering working life. The aim of this paper is to present the LANE study, to estimate representativeness and analyse response rates over time, and also to describe common career pathways and life transitions during the first years of working life. METHODS: Three Swedish national cohorts of nursing students on university degree programmes were recruited to constitute the cohorts. Of 6138 students who were eligible for participation, a total of 4316 consented to participate and responded at baseline (response rate 70%). The cohorts will be followed prospectively for at least three years of their working life. RESULTS: Sociodemographic data in the cohorts were found to be close to population data, as point estimates only differed by 0-3% from population values. Response rates were found to decline somewhat across time, and this decrease was present in all analysed subgroups. During the first year after graduation, nearly all participants had qualified as nurses and had later also held nursing positions. The most common reason for not working was due to maternity leave. About 10% of the cohorts who graduated in 2002 and 2004 intended to leave the profession one year after graduating, and among those who graduated in 2006 the figure was almost twice as high. Intention to leave the profession was more common among young nurses. In the cohort who graduated in 2002, nearly every fifth registered nurse continued to further higher educational training within the health professions. Moreover, in this cohort, about 2% of the participants had left the nursing profession five years after graduating. CONCLUSION: Both high response rates and professional retention imply a potential for a thorough analysis of professional practice and occupational health

Broad and strong memory CD4+ and CD8+ T cells induced by SARS-CoV-2 in UK convalescent individuals following COVID-19

The development of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccines and therapeutics will depend on understanding viral immunity. We studied T cell memory in 42 patients following recovery from COVID-19 (28 with mild disease and 14 with severe disease) and 16 unexposed donors, using interferon-γ-based assays with peptides spanning SARS-CoV-2 except ORF1. The breadth and magnitude of T cell responses were significantly higher in severe as compared with mild cases. Total and spike-specific T cell responses correlated with spike-specific antibody responses. We identified 41 peptides containing CD4+ and/or CD8+ epitopes, including six immunodominant regions. Six optimized CD8+ epitopes were defined, with peptide–MHC pentamer-positive cells displaying the central and effector memory phenotype. In mild cases, higher proportions of SARS-CoV-2-specific CD8+ T cells were observed. The identification of T cell responses associated with milder disease will support an understanding of protective immunity and highlights the potential of including non-spike proteins within future COVID-19 vaccine design