669 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
Regulation of mammary gland branching morphogenesis by the extracellular matrix and its remodeling enzymes.
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
Self-management skills in adolescents with chronic rheumatic disease: A cross-sectional survey
<p>Abstract</p> <p>Background</p> <p>For adolescents with a diagnosis of lifelong chronic illness, mastery of self-management skills is a critical component of the transition to adult care. This study aims to examine self-reported medication adherence and self-care skills among adolescents with chronic rheumatic disease.</p> <p>Methods</p> <p>Cross-sectional survey of 52 adolescent patients in the Pediatric Rheumatology Clinic at UCSF. Outcome measures were self-reported medication adherence, medication regimen knowledge and independence in health care tasks. Predictors of self-management included age, disease perception, self-care agency, demographics and self-reported health status. Bivariate associations were assessed using the Student's t-test, Wilcoxon rank sum test and Fisher exact test as appropriate. Independence in self-management tasks were compared between subjects age 13-16 and 17-20 using the chi-squared test.</p> <p>Results</p> <p>Subjects were age 13-20 years (mean 15.9); 79% were female. Diagnoses included juvenile idiopathic arthritis (44%), lupus (35%), and other rheumatic conditions (21%). Mean disease duration was 5.3 years (SD 4.0). Fifty four percent reported perfect adherence to medications, 40% reported 1-2 missed doses per week, and 6% reported missing 3 or more doses. The most common reason for missing medications was forgetfulness. Among health care tasks, there was an age-related increase in ability to fill prescriptions, schedule appointments, arrange transportation, ask questions of doctors, manage insurance, and recognize symptoms of illness. Ability to take medications as directed, keep a calendar of appointments, and maintain a personal medical file did not improve with age.</p> <p>Conclusions</p> <p>This study suggests that adolescents with chronic rheumatic disease may need additional support to achieve independence in self-management.</p
Effect of bio-engineering on size, shape, composition and rigidity of bacterial microcompartments
Bacterial microcompartments (BMCs) are proteinaceous organelles that are found in a broad range of bacteria and are composed of an outer shell that encases an enzyme cargo representing a specific metabolic process. The outer shell is made from a number of different proteins that form hexameric and pentameric tiles, which interact to allow the formation of a polyhedral edifice. We have previously shown that the Citrobacter freundii BMC associated with 1,2-propanediol utilization can be transferred into Escherichia coli to generate a recombinant BMC and that empty BMCs can be formed from just the shell proteins alone. Herein, a detailed structural and proteomic characterization of the wild type BMC is compared to the recombinant BMC and a number of empty BMC variants by 2D-gel electrophoresis, mass spectrometry, transmission electron microscopy (TEM) and atomic force microscopy (AFM). Specifically, it is shown that the wild type BMC and the recombinant BMC are similar in terms of composition, size, shape and mechanical properties, whereas the empty BMC variants are shown to be smaller, hollow and less malleable
Coordinated optimization of visual cortical maps (II) Numerical studies
It is an attractive hypothesis that the spatial structure of visual cortical
architecture can be explained by the coordinated optimization of multiple
visual cortical maps representing orientation preference (OP), ocular dominance
(OD), spatial frequency, or direction preference. In part (I) of this study we
defined a class of analytically tractable coordinated optimization models and
solved representative examples in which a spatially complex organization of the
orientation preference map is induced by inter-map interactions. We found that
attractor solutions near symmetry breaking threshold predict a highly ordered
map layout and require a substantial OD bias for OP pinwheel stabilization.
Here we examine in numerical simulations whether such models exhibit
biologically more realistic spatially irregular solutions at a finite distance
from threshold and when transients towards attractor states are considered. We
also examine whether model behavior qualitatively changes when the spatial
periodicities of the two maps are detuned and when considering more than 2
feature dimensions. Our numerical results support the view that neither minimal
energy states nor intermediate transient states of our coordinated optimization
models successfully explain the spatially irregular architecture of the visual
cortex. We discuss several alternative scenarios and additional factors that
may improve the agreement between model solutions and biological observations.Comment: 55 pages, 11 figures. arXiv admin note: substantial text overlap with
arXiv:1102.335
Irish general practitioner attitudes toward decriminalisation and medical use of cannabis: results from a national survey.
BACKGROUND: Governmental debate in Ireland on the de facto decriminalisation of cannabis and legalisation for medical use is ongoing. A cannabis-based medicinal product (Sativex®) has recently been granted market authorisation in Ireland. This unique study aimed to investigate Irish general practitioner (GP) attitudes toward decriminalisation of cannabis and assess levels of support for use of cannabis for therapeutic purposes (CTP). METHODS: General practitioners in the Irish College of General Practitioner (ICGP) database were invited to complete an online survey. Anonymous data yielded descriptive statistics (frequencies, percentages) to summarise participant demographic information and agreement with attitudinal statements. Chi-square tests and multi-nominal logistic regression were included. RESULTS: The response rate was 15% (n = 565) which is similar to other Irish national GP attitudinal surveys. Over half of Irish GPs did not support the decriminalisation of cannabis (56.8%). In terms of gender, a significantly higher proportion of males compared with females (40.6 vs. 15%; p < 0.0001) agreed or strongly agreed with this drug policy approach. A higher percentage of GPs with advanced addiction specialist training (level 2) agreed/strongly agreed that cannabis should be decriminalised (54.1 vs. 31.5%; p = 0.021). Over 80% of both genders supported the view that cannabis use has a significant effect on patients' mental health and increases the risk of schizophrenia (77.3%). Over half of Irish GPs supported the legalisation of cannabis for medical use (58.6%). A higher percentage of those who were level 1-trained (trained in addiction treatment but not to an advanced level) agreed/strongly agreed cannabis should be legalised for medical use (p = 0.003). Over 60% agreed that cannabis can have a role in palliative care, pain management and treatment of multiple sclerosis (MS). In the regression response predicator analysis, females were 66.2% less likely to agree that cannabis should be decriminalised, 42.5% less likely to agree that cannabis should be legalised for medical use and 59.8 and 37.6% less likely to agree that cannabis has a role in palliative care and in the treatment of multiple sclerosis (respectively) than males. CONCLUSIONS: The majority of Irish GPs do not support the present Irish governmental drug policy of decriminalisation of cannabis but do support the legalisation of cannabis for therapeutic purposes. Male GPs and those with higher levels of addiction training are more likely to support a more liberal drug policy approach to cannabis for personal use. A clear majority of GPs expressed significant concerns regarding both the mental and physical health risks of cannabis use. Ongoing research into the health and other effects of drug policy changes on cannabis use is required
Abnormal behavior in mice mutant for the Disc1 binding partner, Dixdc1
Disrupted-in-Schizophrenia-1 (DISC1) is a genetic susceptibility locus for major mental illness, including schizophrenia and depression. The Disc1 protein was recently shown to interact with the Wnt signaling protein, DIX domain containing 1 (Dixdc1). Both proteins participate in neural progenitor proliferation dependent on Wnt signaling, and in neural migration independently of Wnt signaling. Interestingly, their effect on neural progenitor proliferation is additive. By analogy to Disc1, mutations in Dixdc1 may lead to abnormal behavior in mice, and to schizophrenia or depression in humans. To explore this hypothesis further, we generated mice mutant at the Dixdc1 locus and analyzed their behavior. Dixdc1−/− mice had normal prepulse inhibition, but displayed decreased spontaneous locomotor activity, abnormal behavior in the elevated plus maze and deficits in startle reactivity. Our results suggest that Dixdc1−/− mice will be a useful tool to elucidate molecular pathophysiology involving Disc1 in major mental illnesses
Engineered Protein Nano-Compartments for Targeted Enzyme Localization
Compartmentalized co-localization of enzymes and their substrates represents an attractive approach for multi-enzymatic synthesis in engineered cells and biocatalysis. Sequestration of enzymes and substrates would greatly increase reaction efficiency while also protecting engineered host cells from potentially toxic reaction intermediates. Several bacteria form protein-based polyhedral microcompartments which sequester functionally related enzymes and regulate their access to substrates and other small metabolites. Such bacterial microcompartments may be engineered into protein-based nano-bioreactors, provided that they can be assembled in a non-native host cell, and that heterologous enzymes and substrates can be targeted into the engineered compartments. Here, we report that recombinant expression of Salmonella enterica ethanolamine utilization (eut) bacterial microcompartment shell proteins in E. coli results in the formation of polyhedral protein shells. Purified recombinant shells are morphologically similar to the native Eut microcompartments purified from S. enterica. Surprisingly, recombinant expression of only one of the shell proteins (EutS) is sufficient and necessary for creating properly delimited compartments. Co-expression with EutS also facilitates the encapsulation of EGFP fused with a putative Eut shell-targeting signal sequence. We also demonstrate the functional localization of a heterologous enzyme (β-galactosidase) targeted to the recombinant shells. Together our results provide proof-of-concept for the engineering of protein nano-compartments for biosynthesis and biocatalysis
Why California retailers stop selling tobacco products, and what their customers and employees think about it when they do: case studies
BACKGROUND: In California, some 40, 000 retailers sell tobacco products. Tobacco's ubiquitousness in retail settings normalizes use and cues smoking urges among former smokers and those attempting cessation. Thus, limiting the number of retailers is regarded as key to ending the tobacco epidemic. In the past decade, independent pharmacies and local grocery chains in California and elsewhere have voluntarily abandoned tobacco sales. No previous studies have examined the reasons for this emerging phenomenon. We sought to learn what motivated retailers to discontinue tobacco sales and what employees and customers thought about their decision. METHODS: We conducted case studies of seven California retailers (three grocery stores, four pharmacies) that had voluntarily ceased tobacco sales within the past 7 years. We interviewed owners, managers, and employees, conducted consumer focus groups, unobtrusively observed businesses and the surrounding environment, and examined any media coverage of each retailer's decision. We analyzed data using qualitative content analysis. RESULTS: For independent pharmacies, the only reason given for the decision to end tobacco sales was that tobacco caused disease and death. Grocers listed health among several factors, including regulatory pressures and wanting to be seen as "making a difference." Media coverage of stores' new policies was limited, and only three retailers alerted customers. Management reported few or no customer complaints and supportive or indifferent employees. Pharmacy employees were pleased to no longer be selling a deadly product. Grocery store management saw the decision to end tobacco sales as enhancing the stores' image and consistent with their inventory of healthy foods. Focus group participants (smokers and nonsmokers) were largely unaware that retailers had stopped selling tobacco; however, almost all supported the decision, viewing it as promoting public health. Many said knowing this made them more likely to shop at the store. Most thought that advertising the store's policy was essential to generate good public relations and tobacco norm changes. CONCLUSIONS: Voluntary retailer abandonment of tobacco sales both reflects and extends social norm changes that have problematized tobacco in California. Our findings suggest that such voluntary initiatives by retailers are welcomed by consumers and should be publicized, enhancing public health efforts
Chemical Genetics Reveals Bacterial and Host Cell Functions Critical for Type IV Effector Translocation by Legionella pneumophila
Delivery of effector proteins is a process widely used by bacterial pathogens to subvert host cell functions and cause disease. Effector delivery is achieved by elaborate injection devices and can often be triggered by environmental stimuli. However, effector export by the L. pneumophila Icm/Dot Type IVB secretion system cannot be detected until the bacterium encounters a target host cell. We used chemical genetics, a perturbation strategy that utilizes small molecule inhibitors, to determine the mechanisms critical for L. pneumophila Icm/Dot activity. From a collection of more than 2,500 annotated molecules we identified specific inhibitors of effector translocation. We found that L. pneumophila effector translocation in macrophages requires host cell factors known to be involved in phagocytosis such as phosphoinositide 3-kinases, actin and tubulin. Moreover, we found that L. pneumophila phagocytosis and effector translocation also specifically require the receptor protein tyrosine phosphate phosphatases CD45 and CD148. We further show that phagocytosis is required to trigger effector delivery unless intimate contact between the bacteria and the host is artificially generated. In addition, real-time analysis of effector translocation suggests that effector export is rate-limited by phagocytosis. We propose a model in which L. pneumophila utilizes phagocytosis to initiate an intimate contact event required for the translocation of pre-synthesized effector molecules. We discuss the need for host cell participation in the initial step of the infection and its implications in the L. pneumophila lifestyle. Chemical genetic screening provides a novel approach to probe the host cell functions and factors involved in host–pathogen interactions
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