787 research outputs found

    Combinatorial Roles of Heparan Sulfate Proteoglycans and Heparan Sulfates in Caenorhabditis elegans Neural Development

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    Heparan sulfate proteoglycans (HSPGs) play critical roles in the development and adult physiology of all metazoan organisms. Most of the known molecular interactions of HSPGs are attributed to the structurally highly complex heparan sulfate (HS) glycans. However, whether a specific HSPG (such as syndecan) contains HS modifications that differ from another HSPG (such as glypican) has remained largely unresolved. Here, a neural model in C. elegans is used to demonstrate for the first time the relationship between specific HSPGs and HS modifications in a defined biological process in vivo. HSPGs are critical for the migration of hermaphrodite specific neurons (HSNs) as genetic elimination of multiple HSPGs leads to 80% defect of HSN migration. The effects of genetic elimination of HSPGs are additive, suggesting that multiple HSPGs, present in the migrating neuron and in the matrix, act in parallel to support neuron migration. Genetic analyses suggest that syndecan/sdn-1 and HS 6-O-sulfotransferase, hst-6, function in a linear signaling pathway and glypican/lon-2 and HS 2-O-sulfotransferase, hst-2, function together in a pathway that is parallel to sdn-1 and hst-6. These results suggest core protein specific HS modifications that are critical for HSN migration. In C. elegans, the core protein specificity of distinct HS modifications may be in part regulated at the level of tissue specific expression of genes encoding for HSPGs and HS modifying enzymes. Genetic analysis reveals that there is a delicate balance of HS modifications and eliminating one HS modifying enzyme in a compromised genetic background leads to significant changes in the overall phenotype. These findings are of importance with the view of HS as a critical regulator of cell signaling in normal development and disease

    Formation of Supermassive Black Holes

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    Evidence shows that massive black holes reside in most local galaxies. Studies have also established a number of relations between the MBH mass and properties of the host galaxy such as bulge mass and velocity dispersion. These results suggest that central MBHs, while much less massive than the host (~ 0.1%), are linked to the evolution of galactic structure. In hierarchical cosmologies, a single big galaxy today can be traced back to the stage when it was split up in hundreds of smaller components. Did MBH seeds form with the same efficiency in small proto-galaxies, or did their formation had to await the buildup of substantial galaxies with deeper potential wells? I briefly review here some of the physical processes that are conducive to the evolution of the massive black hole population. I will discuss black hole formation processes for `seed' black holes that are likely to place at early cosmic epochs, and possible observational tests of these scenarios.Comment: To appear in The Astronomy and Astrophysics Review. The final publication is available at http://www.springerlink.co

    Multiple populations in globular clusters. Lessons learned from the Milky Way globular clusters

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    Recent progress in studies of globular clusters has shown that they are not simple stellar populations, being rather made of multiple generations. Evidence stems both from photometry and spectroscopy. A new paradigm is then arising for the formation of massive star clusters, which includes several episodes of star formation. While this provides an explanation for several features of globular clusters, including the second parameter problem, it also opens new perspectives about the relation between globular clusters and the halo of our Galaxy, and by extension of all populations with a high specific frequency of globular clusters, such as, e.g., giant elliptical galaxies. We review progress in this area, focusing on the most recent studies. Several points remain to be properly understood, in particular those concerning the nature of the polluters producing the abundance pattern in the clusters and the typical timescale, the range of cluster masses where this phenomenon is active, and the relation between globular clusters and other satellites of our Galaxy.Comment: In press (The Astronomy and Astrophysics Review

    Developing a community based psychosocial intervention with older people and third sector workers for anxiety and depression: a qualitative study

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    Background: One-in-five people in the UK experience anxiety and/or depression in later life. However, anxiety and depression remain poorly detected in older people, particularly in those with chronic physical ill health. In the UK, a stepped care approach, to manage common mental health problems, is advocated which includes service provision from non-statutory organisations (including third/voluntary sector). However, evidence to support such provision, including the most effective interventions, is limited. The qualitative study reported here constitutes the first phase of a feasibility study which aims to assess whether third sector workers can deliver a psychosocial intervention to older people with anxiety and/or depression. The aim of this qualitative study is to explore the views of older people and third sector workers about anxiety and depression among older people in order to refine an intervention to be delivered by third sector workers. Methods: Semi-structured interviews with participants recruited through purposive sampling from third sector groups in North Staffordshire. Interviews were digitally recorded with consent, transcribed and analysed using principles of constant comparison. Results: Nineteen older people and 9 third sector workers were interviewed. Key themes included: multiple forms of loss, mental health as a personal burden to bear, having courage and providing/receiving encouragement, self- worth and the value of group activities, and tensions in existing service provision, including barriers and gaps. Conclusions: The experience of loss was seen as central to feelings of anxiety and depression among community- dwelling older people. This study contributes to the evidence pointing to the scale and severity of mental health needs for some older people which can arise from multiple forms of loss, and which present a significant challenge to health, social care and third sector services. The findings informed development of a psychosocial intervention and training for third sector workers to deliver the intervention

    A possible dose–response association between distance to farmers’ markets and roadside produce stands, frequency of shopping, fruit and vegetable consumption, and body mass index among customers in the Southern United States

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    Background: The association between farmers’ market characteristics and consumer shopping habits remains unclear. Our objective was to examine associations among distance to farmers’ markets, amenities within farmers’ markets, frequency of farmers’ market shopping, fruit and vegetable consumption, and body mass index (BMI). We hypothesized that the relationship between frequency of farmers’ market shopping and BMI would be mediated by fruit and vegetable consumption. Methods: In 15 farmers’ markets in northeastern North Carolina, July–September 2015, we conducted a crosssectional survey among 263 farmers’ market customers (199 provided complete address data) and conducted farmers’ market audits. To participate, customers had to be over 18 years of age, and English speaking. Dependent variables included farmers’ market shopping frequency, fruit and vegetable consumption, and BMI. Analysis of variance, adjusted multinomial logistic regression, Poisson regression, and linear regression models, adjusted for age, race, sex, and education, were used to examine associations between distance to farmers’ markets, amenities within farmers’ markets, frequency of farmers’ market shopping, fruit and vegetable consumption, and BMI. Results: Those who reported shopping at farmers’ markets a few times per year or less reported consuming 4.4 (standard deviation = 1.7) daily servings of fruits and vegetables, and those who reported shopping 2 or more times per week reported consuming 5.5 (2.2) daily servings. There was no association between farmers’ market amenities, and shopping frequency or fruit and vegetable consumption. Those who shopped 2 or more times per week had a statistically significantly lower BMI than those who shopped less frequently. There was no evidence of mediation of the relationship between frequency of shopping and BMI by fruit and vegetable consumption. Conclusions: More work should be done to understand factors within farmers’ markets that encourage fruit and vegetable purchases.ECU Open Access Publishing Support Fun

    A Review of Pharmacologic Treatment for Compulsive Buying Disorder

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    At present, no treatment recommendations can be made for compulsive buying disorder. Recent studies have found evidence for the efficacy of psychotherapeutic options, but less is known regarding the best pharmacologic treatment. The purpose of this review is to present and analyze the available published evidence on the pharmacological treatment of compulsive buying disorder. To achieve this, we conducted a review of studies focusing on the pharmacological treatment of compulsive buying by searching the PubMed/MEDLINE database. Selection criteria were applied, and 21 studies were identified. Pharmacological classes reported included antidepressants, mood stabilizers, opioid antagonists, second-generation antipsychotics, and N-methyl-D-aspartate receptor antagonists. We found only placebo-controlled trials for fluvoxamine; none showed effectiveness against placebo. Three open-label trials reported clinical improvement with citalopram; one was followed by a double-blind discontinuation. Escitalopram was effective in an open-label trial but did not show efficacy in the double-blind phase. Memantine was identified as effective in a pilot open-label study. Fluoxetine, bupropion, nortriptyline, clomipramine, topiramate and naltrexone were only reported to be effective in clinical cases. According to the available literature, there is no evidence to propose a specific pharmacologic agent for compulsive buying disorder. Future research is required for a better understanding of both pathogenesis and treatment of this disorder.info:eu-repo/semantics/publishedVersio

    Regulation of mammary gland branching morphogenesis by the extracellular matrix and its remodeling enzymes.

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    A considerable body of research indicates that mammary gland branching morphogenesis is dependent, in part, on the extracellular matrix (ECM), ECM-receptors, such as integrins and other ECM receptors, and ECM-degrading enzymes, including matrix metalloproteinases (MMPs) and their inhibitors, tissue inhibitors of metalloproteinases (TIMPs). There is some evidence that these ECM cues affect one or more of the following processes: cell survival, polarity, proliferation, differentiation, adhesion, and migration. Both three-dimensional culture models and genetic manipulations of the mouse mammary gland have been used to study the signaling pathways that affect these processes. However, the precise mechanisms of ECM-directed mammary morphogenesis are not well understood. Mammary morphogenesis involves epithelial 'invasion' of adipose tissue, a process akin to invasion by breast cancer cells, although the former is a highly regulated developmental process. How these morphogenic pathways are integrated in the normal gland and how they become dysregulated and subverted in the progression of breast cancer also remain largely unanswered questions

    The role of the smartphone in the transition from medical student to foundation trainee: a qualitative interview and focus group study

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    Background The transition from medical student to junior doctor is one of the most challenging in medicine, affecting both doctor and patient health. Opportunities to support this transition have arisen from advances in mobile technology and increased smartphone ownership. Methods This qualitative study consisted of six in-depth interviews and two focus groups with Foundation Year 1 Trainees (intern doctors) and final year medical students within the same NHS Trust. A convenience sample of 14 participants was recruited using chain sampling. Interviews and focus groups were recorded, transcribed verbatim, analysed in accordance with thematic analysis and presented below in keeping with the standards for reporting qualitative research. Results Participants represented both high and low intensity users. They used their smartphones to support their prescribing practices, especially antimicrobials through the MicroGuide™ app. Instant messaging, via WhatsApp, contributed to the existing bleep system, allowing coordination of both work and learning opportunities across place and time. Clinical photographs were recognised as being against regulations but there had still been occasions of use despite this. Concerns about public and colleague perceptions were important to both students and doctors, with participants describing various tactics employed to successfully integrate phone use into their practices. Conclusion This study suggests that both final year medical students and foundation trainees use smartphones in everyday practice. Medical schools and healthcare institutions should seek to integrate such use into core curricula/training to enable safe and effective use and further ease the transition to foundation training. We recommend juniors are reminded of the potential risks to patient confidentiality associated with smartphone use

    Downsizing a human inflammatory protein to a small molecule with equal potency and functionality

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    A significant challenge in chemistry is to rationally reproduce the functional potency of a protein in a small molecule, which is cheaper to manufacture, non-immunogenic, and also both stable and bioavailable. Synthetic peptides corresponding to small bioactive protein surfaces do not form stable structures in water and do not exhibit the functional potencies of proteins. Here we describe a novel approach to growing small molecules with protein-like potencies from a functionally important amino acid of a protein. A 77-residue human inflammatory protein (complement C3a) important in innate immunity is rationally transformed to equipotent small molecules, using peptide surrogates that incorporate a turn-inducing heterocycle with correctly positioned hydrogen-bond-accepting atoms. Small molecule agonists (molecular weigh
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