627 research outputs found
The ADAMTS (A Disintegrin and Metalloproteinase with Thrombospondin motifs) family
The ADAMTS (A Disintegrin and Metalloproteinase with Thrombospondin motifs) enzymes are secreted, multi-domain matrix-associated zinc metalloendopeptidases that have diverse roles in tissue morphogenesis and patho-physiological remodeling, in inflammation and in vascular biology. The human family includes 19 members that can be sub-grouped on the basis of their known substrates, namely the aggrecanases or proteoglycanases (ADAMTS1, 4, 5, 8, 9, 15 and 20), the procollagen N-propeptidases (ADAMTS2, 3 and 14), the cartilage oligomeric matrix protein-cleaving enzymes (ADAMTS7 and 12), the von-Willebrand Factor proteinase (ADAMTS13) and a group of orphan enzymes (ADAMTS6, 10, 16, 17, 18 and 19). Control of the structure and function of the extracellular matrix (ECM) is a central theme of the biology of the ADAMTS, as exemplified by the actions of the procollagen-N-propeptidases in collagen fibril assembly and of the aggrecanases in the cleavage or modification of ECM proteoglycans. Defects in certain family members give rise to inherited genetic disorders, while the aberrant expression or function of others is associated with arthritis, cancer and cardiovascular disease. In particular, ADAMTS4 and 5 have emerged as therapeutic targets in arthritis. Multiple ADAMTSs from different sub-groupings exert either positive or negative effects on tumorigenesis and metastasis, with both metalloproteinase-dependent and -independent actions known to occur. The basic ADAMTS structure comprises a metalloproteinase catalytic domain and a carboxy-terminal ancillary domain, the latter determining substrate specificity and the localization of the protease and its interaction partners; ancillary domains probably also have independent biological functions. Focusing primarily on the aggrecanases and proteoglycanases, this review provides a perspective on the evolution of the ADAMTS family, their links with developmental and disease mechanisms, and key questions for the future
Confab - Systematic generation of diverse low-energy conformers
<p>Abstract</p> <p>Background</p> <p>Many computational chemistry analyses require the generation of conformers, either on-the-fly, or in advance. We present Confab, an open source command-line application for the systematic generation of low-energy conformers according to a diversity criterion.</p> <p>Results</p> <p>Confab generates conformations using the 'torsion driving approach' which involves iterating systematically through a set of allowed torsion angles for each rotatable bond. Energy is assessed using the MMFF94 forcefield. Diversity is measured using the heavy-atom root-mean-square deviation (RMSD) relative to conformers already stored. We investigated the recovery of crystal structures for a dataset of 1000 ligands from the Protein Data Bank with fewer than 1 million conformations. Confab can recover 97% of the molecules to within 1.5 Ã… at a diversity level of 1.5 Ã… and an energy cutoff of 50 kcal/mol.</p> <p>Conclusions</p> <p>Confab is available from <url>http://confab.googlecode.com</url>.</p
The Prevalence of Campylobacter amongst a Free-Range Broiler Breeder Flock Was Primarily Affected by Flock Age
Campylobacter successfully colonizes broiler chickens, but little is known about the longer term natural history of colonization, since most flocks are slaughtered at an immature age. In this study, the prevalence and genetic diversity of Campylobacter colonizing a single free-range broiler breeder flock was investigated over the course of a year. The age of the flock was the most important factor in determining both the prevalence and diversity of Campylobacter over time. There was no correlation with season, temperature, the amount of rain and sunshine, or the dynamics of colonization amongst geographically and temporally matched broiler flocks. The higher prevalence rates coincided with the age at which broiler chickens are typically slaughtered, but then in the absence of bio-security or other intervention methods, and despite changes in flock management, the prevalence fell to significantly lower levels for the remainder of the study. The genetic diversity of Campylobacter increased as the flock aged, implying that genotypes were accumulated within the flock and may persist for a long time. A better understanding of the ecology of Campylobacter within commercial chicken flocks will allow the design of more effective farm-based interventions
Improving breast cancer services for African-American women living in St. Louis
A mixed methods, community-based research study was conducted to understand how provider-level factors contribute to the African-American and white disparity in breast cancer mortality in a lower socioeconomic status area of North St. Louis. This study used mixed methods including: (1) secondary analysis of Missouri Cancer Registry data on all 885 African-American women diagnosed with breast cancer from 2000 to 2008 while living in the geographic area of focus; (2) qualitative interviews with a subset of these women; (3) analysis of data from electronic medical records of the women interviewed; and (4) focus group interviews with community residents, patient navigators, and other health care professionals. 565 women diagnosed with breast cancer from 2000 to 2008 in the geographic area were alive at the time of secondary data analysis; we interviewed (n = 96; 17 %) of these women. Provider-level obstacles to completion of prescribed treatment included fragmented navigation (separate navigators at Federally Qualified Health Centers, surgical oncology, and medical oncology, and no navigation services in surgical oncology). Perhaps related to the latter, women described radiation as optional, often in the same words as they described breast reconstruction. Discontinuous and fragmented patient navigation leads to failure to associate radiation therapy with vital treatment recommendations. Better integrated navigation that continues throughout treatment will increase treatment completion with the potential to improve outcomes in African Americans and decrease the disparity in mortality
Protection from Experimental Cerebral Malaria with a Single Dose of Radiation-Attenuated, Blood-Stage Plasmodium berghei Parasites
BACKGROUND: Whole malaria parasites are highly effective in inducing immunity against malaria. Due to the limited success of subunit based vaccines in clinical studies, there has been a renewed interest in whole parasite-based malaria vaccines. Apart from attenuated sporozoites, there have also been efforts to use live asexual stage parasites as vaccine immunogens. METHODOLOGY AND RESULTS: We used radiation exposure to attenuate the highly virulent asexual blood stages of the murine malaria parasite P. berghei to a non-replicable, avirulent form. We tested the ability of the attenuated blood stage parasites to induce immunity to parasitemia and the symptoms of severe malaria disease. Depending on the mouse genetic background, a single high dose immunization without adjuvant protected mice from parasitemia and severe disease (CD1 mice) or from experimental cerebral malaria (ECM) (C57BL/6 mice). A low dose immunization did not protect against parasitemia or severe disease in either model after one or two immunizations. The protection from ECM was associated with a parasite specific antibody response and also with a lower level of splenic parasite-specific IFN-γ production, which is a mediator of ECM pathology in C57BL/6 mice. Surprisingly, there was no difference in the sequestration of CD8+ T cells and CD45+ CD11b+ macrophages in the brains of immunized, ECM-protected mice. CONCLUSIONS: This report further demonstrates the effectiveness of a whole parasite blood-stage vaccine in inducing immunity to malaria and explicitly demonstrates its effectiveness against ECM, the most pathogenic consequence of malaria infection. This experimental model will be important to explore the formulation of whole parasite blood-stage vaccines against malaria and to investigate the immune mechanisms that mediate protection against parasitemia and cerebral malaria
Dual RNA-Seq of Human Leprosy Lesions Identifies Bacterial Determinants Linked to Host Immune Response
Summary
To understand how the interaction between an intracellular bacterium and the host immune system contributes to outcome at the site of infection, we studied leprosy, a disease that forms a clinical spectrum, in which progressive infection by the intracellular bacterium Mycobacterium leprae is characterized by the production of type I IFNs and antibody production. Dual RNA-seq on patient lesions identifies two independent molecular measures of M. leprae, each of which correlates with distinct aspects of the host immune response. The fraction of bacterial transcripts, reflecting bacterial burden, correlates with a host type I IFN gene signature, known to inhibit antimicrobial responses. Second, the bacterial mRNA:rRNA ratio, reflecting bacterial viability, links bacterial heat shock proteins with the BAFF-BCMA host antibody response pathway. Our findings provide a platform for the interrogation of host and pathogen transcriptomes at the site of infection, allowing insight into mechanisms of inflammation in human disease
Systematic analysis of the ability of Nitric Oxide donors to dislodge biofilms formed by Salmonella enterica and Escherichia coli O157:H7
Biofilms in the industrial environment could be problematic. Encased in extracellular polymeric substances, pathogens within biofilms are significantly more resistant to chlorine and other disinfectants. Recent studies suggest that compounds capable of manipulating nitric oxide-mediated signaling in bacteria could induce dispersal of sessile bacteria and provide a foundation for novel approaches to controlling biofilms formed by some microorganisms. In this work, we compared the ability of five nitric oxide donors (molsidomine, MAHMA NONOate, diethylamine NONOate, diethylamine NONOate diethylammonium salt, spermine NONOate) to dislodge biofilms formed by non-typhoidal Salmonella enterica and pathogenic E. coli on plastic and stainless steel surfaces at different temperatures. All five nitric oxide donors induced significant (35-80%) dispersal of biofilms, however, the degree of dispersal and the optimal dispersal conditions varied. MAHMA NONOate and molsidomine were strong dispersants of the Salmonella biofilms formed on polystyrene. Importantly, molsidomine induced dispersal of up to 50% of the pre-formed Salmonella biofilm at 4 degrees C, suggesting that it could be effective even under refrigerated conditions. Biofilms formed by E. coli O157:H7 were also significantly dispersed. Nitric oxide donor molecules were highly active within 6 hours of application. To better understand mode of action of these compounds, we identified Salmonella genomic region recA-hydN, deletion of which led to an insensitivity to the nitric oxide donors
Characterization of Xenopus Tissue Inhibitor of Metalloproteinases-2: A Role in Regulating Matrix Metalloproteinase Activity during Development
Frog metamorphosis is totally dependent on thyroid hormone (T3) and mimics the postembryonic period around birth in mammals. It is an excellent model to study the molecular basis of postembryonic development in vertebrate. We and others have shown that many, if not all, matrix metalloproteinases (MMPs), which cleave proteins of the extracellular matrix as well as other substrates, are induced by T3 and important for metamorphosis. MMP activity can be inhibited by tissue inhibitors of metalloproteinase (TIMPs). There are 4 TIMPs in vertebrates and their roles in postembryonic development are poorly studied.We analyzed the TIMP2 genes in Xenopus laevis and the highly related species Xenopus tropicalis and discovered that TIMP2 is a single copy gene in Xenopus tropicalis as in mammals but is duplicated in Xenopus laevis. Furthermore, the TIMP2 locus in Xenopus tropicalis genome is different from that in human, suggesting an evolutionary reorganization of the locus. More importantly, we found that the duplicated TIMP2 genes were similarly regulated in the developing limb, remodeling intestine, resorbing tail during metamorphosis. Unexpectedly, like its MMP target genes, the TIMP2 genes were upregulated by T3 during both natural and T3-induced metamorphosis.Our results indicate that TIMP2 is highly conserved among vertebrates and that the TIMP2 locus underwent a chromosomal reorganization during evolution. Furthermore, the unexpected upregulation of TIMP2 genes during metamorphosis suggests that proper balance of MMP activity is important for metamorphosis
Type 2 Diabetes in Xinjiang Uygur Autonomous Region, China
BACKGROUND: The aim of this study was to estimate the prevalence and distribution of type 2 diabetes and to determine the status of type 2 diabetes awareness, treatment, and control in Xinjiang, China. Our data came from the Cardiovascular Risk Survey (CRS) study designed to investigate the prevalence and risk factors for cardiovascular diseases in Xinjiang from October 2007 to March 2010. A total of 14 122 persons (5583 Hans, 4620 Uygurs, and 3919 Kazaks) completed the survey and examination. Diabetes was defined by the American Diabetes Association 2009 criteria. METHODOLOGY/PRINCIPAL FINDINGS: Overall, 9.26% of the Han, 6.23% of the Uygur, and 3.65% of the Kazak adults aged ≥35 years had diabetes. Among diabetes patients, only 53.0% were aware of their blood glucose level, 26.7% were taking hypoglycemic agents, and 10.4% achieved blood glucose control in Han, 35.8% were aware of their blood glucose level, 7.3% were taking hypoglycemic agents, and 3.13% achieved blood glucose control in Uygur, and 23.8% were aware of their blood glucose level, 6.3% were taking hypoglycemic agents, and 1.4% achieved blood glucose control in Kazak, respectively. CONCLUSIONS/SIGNIFICANCE: Our results indicate that diabetes is highly prevalent in Xinjiang. The percentages of those with diabetes who are aware, treated, and controlled are unacceptably low. These results underscore the urgent need to develop national strategies to improve prevention, detection, and treatment of diabetes in Xinjiang, the west China
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