790 research outputs found
Elevated expression of artemis in human fibroblast cells is associated with cellular radiosensitivity and increased apoptosis
Copyright @ 2012 Nature Publishing GroupThis article has been made available through the Brunel Open Access Publishing Fund.Background: The objective of this study was to determine the molecular mechanism(s) responsible for cellular radiosensitivity in two human fibroblast cell lines 84BR and 175BR derived from two cancer patients. Methods: Clonogenic assays were performed following exposure to increasing doses of gamma radiation to confirm radiosensitivity. γ-H2AX foci assays were used to determine the efficiency of DNA double strand break (DSB) repair in cells. Quantitative-PCR (Q-PCR) established the expression levels of key DNA DSB repair proteins. Imaging flow cytometry using Annexin V-FITC was used to compare artemis expression and apoptosis in cells. Results: Clonogenic cellular hypersensitivity in the 84BR and 175BR cell lines was associated with a defect in DNA DSB repair measured by the γ-H2AX foci assay. Q-PCR analysis and imaging flow cytometry revealed a two-fold overexpression of the artemis DNA repair gene which was associated with an increased level of apoptosis in the cells before and after radiation exposure. Over-expression of normal artemis protein in a normal immortalised fibroblast cell line NB1-Tert resulted in increased radiosensitivity and apoptosis. Conclusion: We conclude elevated expression of artemis is associated with higher levels of DNA DSB, radiosensitivity and elevated apoptosis in two radio-hypersensitive cell lines. These data reveal a potentially novel mechanism responsible for radiosensitivity and show that increased artemis expression in cells can result in either radiation resistance or enhanced sensitivity.This work was supported in part by The Vidal Sassoon Foundation USA. This article is made available through the Brunel Open Access Publishing Fund
DEVELOPMENT OF AN AUTOMATED BATCH-PROCESS SOLAR WATER DISINFECTION SYSTEM
One of the shortcomings of solar disinfection of water (SODIS) is the absence of a feedback mechanism indicating treatment completion. This work presents the development of an automated batch-process water disinfection system aimed at solving this challenge. Locally sourced materials in addition to an Arduinomicro processor were used to control the algorithm of the water disinfection system. A comparison of solar radiation sensing accuracy of the system to the Campbell Stokes instrument using student’s t-test showed no significance difference between the two data sets at p=0.05. Test conducted with Escherichia Coli spiked water shows that a 6 log reduction in CFU/ml was achieved within 15 minutes for an average global solar irradiance of 400 W/m2. The system disinfected 11 litres of water in a day for solar radiation of 8.5 MJ/m2/day and Escherichia coli concentration not exceeding 106 CFU/ml. http://dx.doi.org/10.4314/njt.v36i1.3
Socioeconomic inequalities in health among Swedish adolescents - adding the subjective perspective
Abstract Background Socioeconomic inequalities in adolescent health predict future inequalities in adult health. Subjective measures of socioeconomic status (SES) may contribute with an increased understanding of these inequalities. The aim of this study was to investigate socioeconomic health inequalities using both a subjective and an objective measure of SES among Swedish adolescents. Method Cross-sectional HBSC-data from 2002 to 2014 was used with a total sample of 23,088 adolescents aged 11–15 years. Three measures of self-rated health (dependent variables) were assessed: multiple health complaints, life satisfaction and health perception. SES was measured objectively by the Family Affluence Scale (FAS) and subjectively by “perceived family wealth” (independent variables). The trend for health inequalities was investigated descriptively with independent t-tests and the relationship between independent and dependent variables was investigated with multiple logistic regression analysis. Gender, age and survey year was considered as possible confounders. Results Subjective SES was more strongly related to health outcomes than the objective measure (FAS). Also, the relation between FAS and health was weakened and even reversed (for multiple health complaints) when subjective SES was tested simultaneously in regression models (FAS OR: 1.03, CI: 1.00;1.06 and subjective SES OR: 0.66, CI: 0.63;0.68). Conclusions The level of socioeconomic inequalities in adolescent health varied depending on which measure that was used to define SES. When focusing on adolescents, the subjective appraisals of SES is important to consider because they seem to provide a stronger tool for identifying inequalities in health for this group. This finding is important for policy makers to consider given the persistence of health inequalities in Sweden and other high-income countries
Deep-level defects in n-type GaAsBi alloys grown by molecular beam epitaxy at low temperature and their influence on optical properties
Deep-level defects in n-type GaAs1-x Bi x having 0 ≤ x ≤ 0.023 grown on GaAs by molecular beam epitaxy at substrate temperature of 378 °C have been injvestigated by deep level transient spectroscopy. The optical properties of the layers have been studied by contactless electroreflectance and photoluminescence. We find that incorporating Bi suppresses the formation of GaAs-like electron traps, thus reducing the total trap concentration in dilute GaAsBi layers by over two orders of magnitude compared to GaAs grown under the same conditions. In order to distinguish between Bi- and host-related traps and to identify their possible origin, we used the GaAsBi band gap diagram to correlate their activation energies in samples with different Bi contents. This approach was recently successfully applied for the identification of electron traps in n-type GaAs1-x N x and assumes that the activation energy of electron traps decreases with the Bi (or N)-related downward shift of the conduction band. On the basis of this diagram and under the support of recent theoretical calculations, at least two Bi-related traps were revealed and associated with Bi pair defects, i.e. (VGa+BiGa)(-/2-) and (AsGa+BiGa)(0/1-). In the present work it is shown that these defects also influence the photoluminescence properties of GaAsBi alloys
Effect of Sida corymbosa leaf extract on serum uric acid, urea and creatinine levels of alloxan-induced diabetic albino wistar rats
This study was designed to investigate the effect of Sida corymbosa (SC) leaf extract on serum uric acid, urea and creatinine levels in alloxan induced diabetic albino wistar rats. A total of 30 albino wistar rats each weighing 100g were assembled and divided into three groups (A-C) consisting of 10 rats in each group. Group A received SC treatment, B did not receive SC treatment, while group C served as the control group. 400mg/kg of aqueous extract of SC leaf was administered orally to the rats in group A but not in group B, while group C received only water for 7 days. Blood samples were collected into plain containers for estimation of serum uric acid, urea and creatinine. Serum uric acid, urea and creatinine were analyzed using Uricase, Urease-Berthlot and Jaffe Slot Alkaline picrate methods respectively. Results showed a significant increase in the mean serum levels of uric acid, urea and creatinine after SC treatment, when compared to the pre- treatment status. Similarly, there was a significant decrease in the mean weight of the rats after SC administration. Therefore, SC may have potential harmful effect on the kidney.Keywords: Sida corymbosa, Kidney, Urea, Uric Acid, Creatinine
Influence of training status on high-intensity intermittent performance in response to β-alanine supplementation
Recent investigations have suggested that highly trained athletes may be less responsive to the ergogenic effects of β-alanine (BA) supplementation than recreationally active individuals due to their elevated muscle buffering capacity. We investigated whether training status influences the effect of BA on repeated Wingate performance. Forty young males were divided into two groups according to their training status (trained: T, and non-trained: NT cyclists) and were randomly allocated to BA and a dextrose-based placebo (PL) groups, providing four experimental conditions: NTPL, NTBA, TPL, TBA. BA (6.4 g day-1 ) or PL was ingested for 4 weeks, with participants completing four 30-s lower-body Wingate bouts, separated by 3 min, before and after supplementation. Total work done was significantly increased following supplementation in both NTBA (p = 0.03) and TBA (p = 0.002), and it was significantly reduced in NTPL (p = 0.03) with no difference for TPL (p = 0.73). BA supplementation increased mean power output (MPO) in bout 4 for the NTBA group (p = 0.0004) and in bouts 1, 2 and 4 for the TBA group (p ≤ 0.05). No differences were observed in MPO for NTPL and TPL. BA supplementation was effective at improving repeated high-intensity cycling performance in both trained and non-trained individuals, highlighting the efficacy of BA as an ergogenic aid for high-intensity exercise regardless of the training status of the individual
Measurement of the Bottom-Strange Meson Mixing Phase in the Full CDF Data Set
We report a measurement of the bottom-strange meson mixing phase \beta_s
using the time evolution of B0_s -> J/\psi (->\mu+\mu-) \phi (-> K+ K-) decays
in which the quark-flavor content of the bottom-strange meson is identified at
production. This measurement uses the full data set of proton-antiproton
collisions at sqrt(s)= 1.96 TeV collected by the Collider Detector experiment
at the Fermilab Tevatron, corresponding to 9.6 fb-1 of integrated luminosity.
We report confidence regions in the two-dimensional space of \beta_s and the
B0_s decay-width difference \Delta\Gamma_s, and measure \beta_s in [-\pi/2,
-1.51] U [-0.06, 0.30] U [1.26, \pi/2] at the 68% confidence level, in
agreement with the standard model expectation. Assuming the standard model
value of \beta_s, we also determine \Delta\Gamma_s = 0.068 +- 0.026 (stat) +-
0.009 (syst) ps-1 and the mean B0_s lifetime, \tau_s = 1.528 +- 0.019 (stat) +-
0.009 (syst) ps, which are consistent and competitive with determinations by
other experiments.Comment: 8 pages, 2 figures, Phys. Rev. Lett 109, 171802 (2012
Nematode and Arthropod Genomes Provide New Insights into the Evolution of Class 2 B1 GPCRs
Nematodes and arthropods are the most speciose animal groups and possess Class 2 B1 G-protein coupled receptors
(GPCRs). Existing models of invertebrate Class 2 B1 GPCR evolution are mainly centered on Caenorhabditis elegans and
Drosophila melanogaster and a few other nematode and arthropod representatives. The present study reevaluates the
evolution of metazoan Class 2 B1 GPCRs and orthologues by exploring the receptors in several nematode and arthropod
genomes and comparing them to the human receptors. Three novel receptor phylogenetic clusters were identified and
designated cluster A, cluster B and PDF-R-related cluster. Clusters A and B were identified in several nematode and
arthropod genomes but were absent from D. melanogaster and Culicidae genomes, whereas the majority of the members of
the PDF-R-related cluster were from nematodes. Cluster A receptors were nematode and arthropod-specific but shared a
conserved gene environment with human receptor loci. Cluster B members were orthologous to human GCGR, PTHR and
Secretin members with which they probably shared a common origin. PDF-R and PDF-R related clusters were present in
representatives of both nematodes and arthropods. The results of comparative analysis of GPCR evolution and diversity in
protostomes confirm previous notions that C. elegans and D. melanogaster genomes are not good representatives of
nematode and arthropod phyla. We hypothesize that at least four ancestral Class 2 B1 genes emerged early in the metazoan
radiation, which after the protostome-deuterostome split underwent distinct selective pressures that resulted in duplication
and deletion events that originated the current Class 2 B1 GPCRs in nematode and arthropod genomes.This work was supported by the Portuguese Foundation for Science and Technology (FCT) project PTDC/BIA-BCM/114395/2009, by the European
Regional Development Fund through COMPETE and FCT under the project ‘‘PEst-C/MAR/LA0015/2011.’’ RCF is in receipt of an FCT grant (SFRH/BPD/89811/2012)
and JCRC is supported by auxiliary research contract FCT Pluriannual funds attributed to CCMAR. The funders had no role in study design, data collection and
analysis, decision to publish, or preparation of the manuscript
Effect of cucumber consumption on plasma creatinine, urea, uric acid and glucose level in apparently healthy students of college of health sciences, Nnamdi Azikiwe university, Nnewi campus, Anambra state, Nigeria
This study was designed to investigate the effect of oral intake of cucumber on plasma creatinine (Cr), urea, uric acid (Ua) and blood glucose in young apparently healthy students. A total of 29 subjects (14 males and 15 females) were recruited. Each subject was advised to abstain from cucumber and similar vegetables consumption for two weeks. Thereafter, they received 400 g of whole cucumber for 21days prior to their daily breakfast. 5mls each of baseline (day zero) and post consumption (day 22) samples were collected after overnight fast into fluoride oxalate and lithium heparin containers for glucose and other biochemical parameters respectively. Plasma glucose, urea, creatinine and uric acid were analyzed using standard methods. There was a significant decrease in the mean plasma glucose level in post cucumber consumption when compared to the pre-cucumber consumption (4.280.46 vs 4.680.35; p<0.05). However, plasma levels of urea, uric acid and creatinine did not differ significantly between pre and post–cucumber consumption. This study revealed hypoglycaemic effect of cucumber consumption with no harmful effect on the kidney. Therefore, cucumber consumption could be of importance in prevention and management of diabetes mellitus. . Keywords: Cucumber, urea, glucose, Uric acid, Creatinine
Cooperation among cancer cells: applying game theory to cancer
Cell cooperation promotes many of the hallmarks of cancer via the secretion of diffusible factors that can affect cancer cells or stromal cells in the tumour microenvironment. This cooperation cannot be explained simply as the collective action of cells for the benefit of the tumour because non-cooperative subclones can constantly invade and free-ride on the diffusible factors produced by the cooperative cells. A full understanding of cooperation among the cells of a tumour requires methods and concepts from evolutionary game theory, which has been used successfully in other areas of biology to understand similar problems but has been underutilized in cancer research. Game theory can provide insights into the stability of cooperation among cells in a tumour and into the design of potentially evolution-proof therapies that disrupt this cooperation
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