152 research outputs found
Regulation of pituitary MT1 melatonin receptor expression by gonadotrophin-releasing hormone (GnRH) and early growth response factor-1 (Egr-1) : in vivo and in vitro studies
Copyright: © 2014 Bae et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Funding: This work was funded by the UK Biotechnology and Biological Sciences Research Council (BBSRC; grant BB/F020309/1; http://www.bbsrc.ac.uk/home/home.aspx). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Peer reviewedPublisher PD
Ultradian Cortisol Pulsatility Encodes a Distinct, Biologically Important Signal
Cortisol is released in ultradian pulses. The biological relevance of the resulting fluctuating cortisol concentration has not been explored.Determination of the biological consequences of ultradian cortisol pulsatility.A novel flow through cell culture system was developed to deliver ultradian pulsed or continuous cortisol to cells. The effects of cortisol dynamics on cell proliferation and survival, and on gene expression were determined. In addition, effects on glucocorticoid receptor (GR) expression levels and phosphorylation, as a potential mediator, were measured.Pulsatile cortisol caused a significant reduction in cell survival compared to continuous exposure of the same cumulative dose, due to increased apoptosis. Comprehensive analysis of the transcriptome response by microarray identified genes with a differential response to pulsatile versus continuous glucocorticoid delivery. These were confirmed with qRT-PCR. Several transcription factor binding sites were enriched in these differentially regulated target genes, including CCAAT-displacement protein (CDP). A CDP regulated reporter gene (MMTV-luc) was, as predicted, also differentially regulated by pulsatile compared to continuous cortisol delivery. Importantly there was no effect of cortisol delivery kinetics on either GR expression, or activation (GR phosphoSer(211)).Cortisol oscillations exert important effects on target cell gene expression, and phenotype. This is not due to differences in cumulative cortisol exposure, or either expression, or activation of the GR. This suggests a novel means to regulate GR function
Association between substance use and psychosocial characteristics among adolescents of the Seychelles
BACKGROUND: We examined the associations between substance use (cigarette smoking, alcohol drinking, and cannabis use) and psychosocial characteristics at the individual and family levels among adolescents of the Seychelles, a rapidly developing small island state in the African region. METHODS: A school survey was conducted in a representative sample of 1432 students aged 11-17 years from all secondary schools. Data came from a self-administered anonymous questionnaire conducted along a standard methodology (Global School-based Health Survey, GSHS). Risk behaviors and psychosocial characteristics were dichotomized. Association analyses were adjusted for a possible classroom effect. RESULTS: The prevalence of cigarette smoking, alcohol drinking and cannabis use was higher in boys than in girls and increased with age. Age-adjusted and multivariate analyses showed that several individual level characteristics (e.g. suicidal ideation and truancy) and family level characteristics (e.g. poor parental monitoring) were associated with substance use among students. CONCLUSIONS: Our results suggest that health promotion programs should simultaneously address multiple risk behaviors and take into account a wide range of psychosocial characteristics of the students at the individual and family levels
Prediction of Extracellular Proteases of the Human Pathogen Helicobacter pylori Reveals Proteolytic Activity of the Hp1018/19 Protein HtrA
Exported proteases of Helicobacter pylori (H. pylori) are potentially involved in pathogen-associated disorders leading to gastric inflammation and neoplasia. By comprehensive sequence screening of the H. pylori proteome for predicted secreted proteases, we retrieved several candidate genes. We detected caseinolytic activities of several such proteases, which are released independently from the H. pylori type IV secretion system encoded by the cag pathogenicity island (cagPAI). Among these, we found the predicted serine protease HtrA (Hp1019), which was previously identified in the bacterial secretome of H. pylori. Importantly, we further found that the H. pylori genes hp1018 and hp1019 represent a single gene likely coding for an exported protein. Here, we directly verified proteolytic activity of HtrA in vitro and identified the HtrA protease in zymograms by mass spectrometry. Overexpressed and purified HtrA exhibited pronounced proteolytic activity, which is inactivated after mutation of Ser205 to alanine in the predicted active center of HtrA. These data demonstrate that H. pylori secretes HtrA as an active protease, which might represent a novel candidate target for therapeutic intervention strategies
Spatiotemporally Controlled Cardiac Conduction Block Using High-Frequency Electrical Stimulation
Background:
Methods for the electrical inhibition of cardiac excitation have long been sought to control excitability and conduction, but to date remain largely impractical. High-amplitude alternating current (AC) stimulation has been known to extend cardiac action potentials (APs), and has been recently exploited to terminate reentrant arrhythmias by producing reversible conduction blocks. Yet, low-amplitude currents at similar frequencies have been shown to entrain cardiac tissues by generation of repetitive APs, leading in some cases to ventricular fibrillation and hemodynamic collapse in vivo. Therefore, an inhibition method that does not lead to entrainment – irrespective of the stimulation amplitude (bound to fluctuate in an in vivo setting) – is highly desirable.
Methodology/Principal Findings:
We investigated the effects of broader amplitude and frequency ranges on the inhibitory effects of extracellular AC stimulation on HL-1 cardiomyocytes cultured on microelectrode arrays, using both sinusoidal and square waveforms. Our results indicate that, at sufficiently high frequencies, cardiac tissue exhibits a binary response to stimulus amplitude with either prolonged APs or no effect, thereby effectively avoiding the risks of entrainment by repetitive firing observed at lower frequencies. We further demonstrate the ability to precisely define reversible local conduction blocks in beating cultures without influencing the propagation activity in non-blocked areas. The conduction blocks were spatiotemporally controlled by electrode geometry and stimuli duration, respectively, and sustainable for long durations (300 s).
Conclusion/Significance:
Inhibition of cardiac excitation induced by high-frequency AC stimulation exhibits a binary response to amplitude above a threshold frequency, enabling the generation of reversible conduction blocks without the risks of entrainment. This inhibition method could yield novel approaches for arrhythmia modeling in vitro, as well as safer and more efficacious tools for in vivo cardiac mapping and radio-frequency ablation guidance applications
Are mental health and binge drinking associated in Dutch adolescents? Cross-sectional public health study
<p>Abstract</p> <p>Background</p> <p>Depression and anxiety disorders have a high disease burden and as many as 15% of young people report mental health problems. Binge drinking, which is a particularly harmful way of consuming alcohol, is common among secondary school students. The aim of this study was to examine the association between binge drinking and self-reported mental health in boys and girls aged 12 to 18 years.</p> <p>Findings</p> <p>This cross-sectional analysis was performed on data collected by the Community Health Service (GGD) Brabant Zuidoost, the Netherlands, in 2007. In this Youth Survey, 10 090 randomly selected adolescents aged 12 tot 18 years were each sent a letter, a questionnaire, and a user name and log-in code for if they preferred to complete the Internet version of the questionnaire. Mental health was assessed using the Mental Health Inventory (MHI-5), a short 5-item questionnaire to detect feelings of depression and anxiety. Participants were asked about current alcohol consumption, their relationship with their parents, drug use, and sociodemographic data.</p> <p>Corrected for confounders, binge drinking and mental health problems were associated in the 12 to 15 year old girls (OR 2.43; 95% CI 1.86-3.17, p = 0.000) and boys (OR 1.64, 95% CI 1.19-2.27, p = 0.003). The majority of the 16 to 18 year old adolescents had been binge drinking in the previous 4 weeks (69.6% boys and 56.8% girls). In this age group, boys with mental health problems were less likely to be classified as binge drinkers than were boys without mental health problems (OR 0.63, 95% CI 0.45-0.87, p = 0.005). No such association between binge drinking and mental health was found in girls of this age.</p> <p>Conclusion</p> <p>Girls and boys aged 12-15 years were classified as binge drinkers significantly more often when they reported poor mental health. Because binge drinking damages the brain, especially at a young age, it is important that health professionals are alert to possible binge drinking when young adolescents report mental health problems and should ask their patients about their drinking behaviour. Likewise, if youngsters under 16 present with binge drinking, they should be asked whether they are anxious or depressed.</p
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Diamonds, gold and crime displacement: Hatton Garden, and the evolution of organised crime in the UK
The 2015 Hatton Garden Heist was described as the ‘largest burglary in English legal history’. However, the global attention that this spectacular crime attracted to ‘The Garden’ tended to concentrate upon the value of the stolen goods and the vintage of the burglars. What has been ignored is how the burglary shone a spotlight into Hatton Garden itself, as an area with a unique ‘upperworld’ commercial profile and skills cluster that we identify as an incubator and facilitator for organised crime. The Garden is the UK’s foremost jewellery production and retail centre and this paper seeks to explore how Hatton Garden’s businesses integrated with a fluid criminal population to transition, through hosting lucrative (and bureaucratically complex) VAT gold frauds from 1980 to the early 1990s, to become a major base for sophisticated acquisitive criminal activities. Based on extensive interviews over a thirty year period, evidence from a personal research archive and public records, this paper details a cultural community with a unique criminal profile due to the particularities of its geographical location, ethnic composition, trading culture, skills base and international connections. The processes and structures that facilitate criminal markets are largely under-researched (Antonopoulos et al. 2015: 11), and this paper considers how elements of Hatton Garden’s ‘upperworld’ businesses integrated with project criminals, displaced by policing strategies, to effect this transition
A systematic review of longitudinal studies on the association between depression and smoking in adolescents
<p>Abstract</p> <p>Background</p> <p>It is well-established that smoking and depression are associated in adolescents, but the temporal ordering of the association is subject to debate.</p> <p>Methods</p> <p>Longitudinal studies in English language which reported the onset of smoking on depression in non clinical populations (age 13-19) published between January 1990 and July 2008 were selected from PubMed, OVID, and PsychInfo databases. Study characteristics were extracted. Meta-analytic pooling procedures with random effects were used.</p> <p>Results</p> <p>Fifteen studies were retained for analysis. The pooled estimate for smoking predicting depression in 6 studies was 1.73 (95% CI: 1.32, 2.40; p < 0.001). The pooled estimate for depression predicting smoking in 12 studies was 1.41 (95% CI: 1.21, 1.63; p < 0.001). Studies that used clinical measures of depression were more likely to report a bidirectional effect, with a stronger effect of depression predicting smoking.</p> <p>Conclusion</p> <p>Evidence from longitudinal studies suggests that the association between smoking and depression is bidirectional. To better estimate these effects, future research should consider the potential utility of: (a) shorter intervals between surveys with longer follow-up time, (b) more accurate measurement of depression, and (c) adequate control of confounding.</p
Transplantation of Specific Human Astrocytes Promotes Functional Recovery after Spinal Cord Injury
Repairing trauma to the central nervous system by replacement of glial support
cells is an increasingly attractive therapeutic strategy. We have focused on the
less-studied replacement of astrocytes, the major support cell in the central
nervous system, by generating astrocytes from embryonic human glial precursor
cells using two different astrocyte differentiation inducing factors. The
resulting astrocytes differed in expression of multiple proteins thought to
either promote or inhibit central nervous system homeostasis and regeneration.
When transplanted into acute transection injuries of the adult rat spinal cord,
astrocytes generated by exposing human glial precursor cells to bone
morphogenetic protein promoted significant recovery of volitional foot
placement, axonal growth and notably robust increases in neuronal survival in
multiple spinal cord laminae. In marked contrast, human glial precursor cells
and astrocytes generated from these cells by exposure to ciliary neurotrophic
factor both failed to promote significant behavioral recovery or similarly
robust neuronal survival and support of axon growth at sites of injury. Our
studies thus demonstrate functional differences between human astrocyte
populations and suggest that pre-differentiation of precursor cells into a
specific astrocyte subtype is required to optimize astrocyte replacement
therapies. To our knowledge, this study is the first to show functional
differences in ability to promote repair of the injured adult central nervous
system between two distinct subtypes of human astrocytes derived from a common
fetal glial precursor population. These findings are consistent with our
previous studies of transplanting specific subtypes of rodent glial precursor
derived astrocytes into sites of spinal cord injury, and indicate a remarkable
conservation from rat to human of functional differences between astrocyte
subtypes. In addition, our studies provide a specific population of human
astrocytes that appears to be particularly suitable for further development
towards clinical application in treating the traumatically injured or diseased
human central nervous system
Antiangiogenic Activity of 2-Deoxy-D-Glucose
During tumor angiogenesis, endothelial cells (ECs) are engaged in a number of energy consuming biological processes, such as proliferation, migration, and capillary formation. Since glucose uptake and metabolism are increased to meet this energy need, the effects of the glycolytic inhibitor 2-deoxy-D-glucose (2-DG) on in vitro and in vivo angiogenesis were investigated.In cell culture, 2-DG inhibited EC growth, induced cytotoxicity, blocked migration, and inhibited actively forming but not established endothelial capillaries. Surprisingly, 2-DG was a better inhibitor of these EC properties than two more efficacious glycolytic inhibitors, 2-fluorodeoxy-D-glucose and oxamate. As an alternative to a glycolytic inhibitory mechanism, we considered 2-DG's ability to interfere with endothelial N-linked glycosylation. 2-DG's effects were reversed by mannose, an N-linked glycosylation precursor, and at relevant concentrations 2-DG also inhibited synthesis of the lipid linked oligosaccharide (LLO) N-glycosylation donor in a mannose-reversible manner. Inhibition of LLO synthesis activated the unfolded protein response (UPR), which resulted in induction of GADD153/CHOP and EC apoptosis (TUNEL assay). Thus, 2-DG's effects on ECs appeared primarily due to inhibition of LLOs synthesis, not glycolysis. 2-DG was then evaluated in two mouse models, inhibiting angiogenesis in both the matrigel plug assay and the LH(BETA)T(AG) transgenic retinoblastoma model.In conclusion, 2-DG inhibits endothelial cell angiogenesis in vitro and in vivo, at concentrations below those affecting tumor cells directly, most likely by interfering with N-linked glycosylation rather than glycolysis. Our data underscore the importance of glucose metabolism on neovascularization, and demonstrate a novel approach for anti-angiogenic strategies
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