953 research outputs found
Assessing the psychometric and ecometric properties of neighborhood scales using adolescent survey data from urban and rural Scotland
This work was supported by NHS Health Scotland and the University of St Andrews.Background: Despite the well-established need for specific measurement instruments to examine the relationship between neighborhood conditions and adolescent well-being outcomes, few studies have developed scales to measure features of the neighborhoods in which adolescents reside. Moreover, measures of neighborhood features may be operationalised differently by adolescents living in different levels of urban/rurality. This has not been addressed in previous studies. The objectives of this study were to: 1) establish instruments to measure adolescent neighborhood features at both the individual and neighborhood level, 2) assess their psychometric and ecometric properties, 3) test for invariance by urban/rurality, and 4) generate neighborhood level scores for use in further analysis. Methods: Data were from the Scottish 2010 Health Behaviour in School-aged Children Survey, which included an over-sample of rural adolescents. The survey responses of interest came from questions designed to capture different facets of the local area in which each respondent resided. Intermediate data zones were used as proxies for neighborhoods. Internal consistency was evaluated by Cronbach’s alpha. Invariance was examined using confirmatory factor analysis. Multilevel models were used to estimate ecometric properties and generate neighborhood scores. Results: Two constructs labeled neighborhood social cohesion and neighborhood disorder were identified. Adjustment was made to the originally specified model to improve model fit and measures of invariance. At the individual level, reliability was .760 for social cohesion and .765 for disorder, and between .524 and .571 for both constructs at the neighborhood level. Individuals in rural areas experienced greater neighborhood social cohesion and lower levels of neighborhood disorder compared with those in urban areas. Conclusions: The scales are appropriate for measuring neighborhood characteristics experienced by adolescents across urban and rural Scotland, and can be used in future studies of neighborhoods and health. However, trade-offs between neighborhood sample size and reliability must be considered.Publisher PDFPeer reviewe
The Human Minor Histocompatibility Antigen1 Is a RhoGAP
The human minor Histocompatibility Antigen HMHA-1 is a major target of immune responses after allogeneic stem cell transplantation applied for the treatment of leukemia and solid tumors. The restriction of its expression to hematopoietic cells and many solid tumors raised questions regarding its cellular functions. Sequence analysis of the HMHA-1 encoding HMHA1 protein revealed the presence of a possible C-terminal RhoGTPase Activating Protein (GAP) domain and an N-terminal BAR domain. Rho-family GTPases, including Rac1, Cdc42, and RhoA are key regulators of the actin cytoskeleton and control cell spreading and migration. RhoGTPase activity is under tight control as aberrant signaling can lead to pathology, including inflammation and cancer. Whereas Guanine nucleotide Exchange Factors (GEFs) mediate the exchange of GDP for GTP resulting in RhoGTPase activation, GAPs catalyze the low intrinsic GTPase activity of active RhoGTPases, resulting in inactivation. Here we identify the HMHA1 protein as a novel RhoGAP. We show that HMHA1 constructs, lacking the N-terminal region, negatively regulate the actin cytoskeleton as well as cell spreading. Furthermore, we show that HMHA1 regulates RhoGTPase activity in vitro and in vivo. Finally, we demonstrate that the HMHA1 N-terminal BAR domain is auto-inhibitory as HMHA1 mutants lacking this region, but not full-length HMHA1, showed GAP activity towards RhoGTPases. In conclusion, this study shows that HMHA1 acts as a RhoGAP to regulate GTPase activity, cytoskeletal remodeling and cell spreading, which are crucial functions in normal hematopoietic and cancer cells
The disruption of proteostasis in neurodegenerative diseases
Cells count on surveillance systems to monitor and protect the cellular proteome which, besides being highly heterogeneous, is constantly being challenged by intrinsic and environmental factors. In this context, the proteostasis network (PN) is essential to achieve a stable and functional proteome. Disruption of the PN is associated with aging and can lead to and/or potentiate the occurrence of many neurodegenerative diseases (ND). This not only emphasizes the importance of the PN in health span and aging but also how its modulation can be a potential target for intervention and treatment of human diseases.info:eu-repo/semantics/publishedVersio
Cathelicidin-like Helminth Defence Molecules (HDMs) Absence of Cytotoxic, Anti-microbial and Anti-protozoan Activities Imply a Specific Adaptation to Immune Modulation
Host defence peptides (HDPs) are expressed throughout the animal and plant kingdoms. They have multifunctional roles in the defence against infectious agents of mammals, possessing both bactericidal and immune-modulatory activities. We have identified a novel family of molecules secreted by helminth parasites (helminth defence molecules; HDMs) that exhibit similar structural and biochemical characteristics to the HDPs. Here, we have analyzed the functional activities of four HDMs derived from Schistosoma mansoni and Fasciola hepatica and compared them to human, mouse, bovine and sheep HDPs. Unlike the mammalian HDPs the helminth-derived HDMs show no antimicrobial activity and are non-cytotoxic to mammalian cells (macrophages and red blood cells). However, both the mammalian- and helminth-derived peptides suppress the activation of macrophages by microbial stimuli and alter the response of B cells to cytokine stimulation. Therefore, we hypothesise that HDMs represent a novel family of HDPs that evolved to regulate the immune responses of their mammalian hosts by retaining potent immune modulatory properties without causing deleterious cytotoxic effects. © 2013 Thivierge et al
Myeloperoxidase gene-463G > A polymorphism and premature coronary artery disease
We investigated the association between myeloperoxidase gene -463G > A polymorphism and premature coronary artery disease (CAD) in two Chinese population samples: 229 patients and 230 controls. Genotypes were determined by ligase detection reaction-polymerase chain reaction sequencing and the grouping technique. We found lower frequencies of both the A/A genotype and the A allele in patients (p < 0.05). Multivariate logistic regression showed that the risk of premature CAD in subjects carrying the AA genotype was reduced by 83% in relation to individuals carrying the G/G genotype (OR = 0.172, 95% CI: 0.057-0.526, p = 0.002). Our results indicate that -463G > A polymorphism of the myeloperoxidase gene is associated with premature CAD in Chinese individuals, suggesting that the AA genotype is a protective factor against premature CAD
Dual isotope analyses indicate efficient processing of atmospheric nitrate by forested watersheds in the northeastern U.S.
Author Posting. © Springer, 2008. This is the author's version of the work. It is posted here by permission of Springer for personal use, not for redistribution. The definitive version was published in Biogeochemistry 90 (2008): 15-27, doi:10.1007/s10533-008-9227-2.Nitrogen from atmospheric deposition serves as the dominant source of new nitrogen to forested ecosystems in the northeastern U.S.. By combining isotopic data obtained using the denitrifier method, with chemistry and hydrology measurements we determined the relative importance of sources and control mechanisms on nitrate (NO3-) export from five forested watersheds in the Connecticut River watershed. Microbially produced NO3- was the dominant source (82-100%) of NO3- to the sampled streams as indicated by the δ15N and δ18O of NO3-. Seasonal variations in the δ18O-NO3- in streamwater are controlled by shifting hydrology and temperature affects on biotic processing, resulting in a relative increase in unprocessed NO3- export during winter months. Mass balance estimates find that the unprocessed atmospherically derived NO3- stream flux represents less than 3% of the atmospherically delivered wet NO3- flux to the region. This suggests that despite chronically elevated nitrogen deposition these forests are not nitrogen saturated and are retaining, removing, and reprocessing the vast majority of NO3- delivered to them throughout the year. These results confirm previous work within Northeastern U.S. forests and extend observations to watersheds not dominated by a snow-melt driven hydrology. In contrast to previous work, unprocessed atmospherically derived NO3- export is associated with the period of high recharge and low biotic activity as opposed to spring snowmelt and other large runoff events.This work was funded by an EPA STAR Fellowship (FP-91637501-1) and a grant from QLF/The Sound Conservancy to RTB
The PPARγ Agonist Rosiglitazone Impairs Colonic Inflammation in Mice with Experimental Colitis
Various animal models showed that peroxisome proliferator-activated receptor (PPAR)γ agonists, when given as a gavage shortly preceding colitis induction, protect against inflammatory bowel disease (IBD). We have examined the effects of 16 days rosiglitazone treatment via the diet prior to dextran sodium sulphate (DSS)-induced colitis in mice. After 7 days DSS in the drinking water, rosiglitazone-fed mice had lost significantly more weight than control mice. Rosiglitazone-treated mice had more diarrhea, weight of colon and spleen were increased, and length of colon was decreased. Histology showed that rosiglitazone-treated mice had more severe colitis, mainly caused by more ulceration, crypt loss, and edema. Immunofluorescence showed a loss of tight junction structure Zonula Occludens protein 1 (ZO-1) in colons of rosiglitazone-treated mice as compared to control mice. Also, serum amyloid P component (SAP) concentrations in plasma were increased. However, concentrations of tumor necrosis factor (TNF)-α and interferon (IFN)-γ in colon homogenates, and TNF-α in spleen homogenates were significantly decreased, whereas interleukin (IL)-10 in spleen homogenates was increased. Other cytokines (IL-2, IL-4, IL-6, IL-12p70 and monocyte chemotactic protein (MCP)-1) and myeloperoxidase (MPO) concentrations showed no differences. In conclusion, 16 days pretreatment with rosiglitazone impaired DSS-induced colitis in mice
A Gene-Phenotype Network for the Laboratory Mouse and Its Implications for Systematic Phenotyping
The laboratory mouse is the pre-eminent model organism for the dissection of human disease pathways. With the advent of a comprehensive panel of gene knockouts, projects to characterise the phenotypes of all knockout lines are being initiated. The range of genotype-phenotype associations can be represented using the Mammalian Phenotype ontology. Using publicly available data annotated with this ontology we have constructed gene and phenotype networks representing these associations. These networks show a scale-free, hierarchical and modular character and community structure. They also exhibit enrichment for gene coexpression, protein-protein interactions and Gene Ontology annotation similarity. Close association between gene communities and some high-level ontology terms suggests that systematic phenotyping can provide a direct insight into underlying pathways. However some phenotypes are distributed more diffusely across gene networks, likely reflecting the pleiotropic roles of many genes. Phenotype communities show a many-to-many relationship to human disease communities, but stronger overlap at more granular levels of description. This may suggest that systematic phenotyping projects should aim for high granularity annotations to maximise their relevance to human disease
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