272 research outputs found

    Pathogenesis of graft-versus-host-disease

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    Radial Spoke Proteins of \u3cem\u3eChlamydomonas\u3c/em\u3e Flagella

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    The radial spoke is a ubiquitous component of `9+2\u27 cilia and flagella, and plays an essential role in the control of dynein arm activity by relaying signals from the central pair of microtubules to the arms. The Chlamydomonas reinhardtii radial spoke contains at least 23 proteins, only 8 of which have been characterized at the molecular level. Here, we use mass spectrometry to identify 10 additional radial spoke proteins. Many of the newly identified proteins in the spoke stalk are predicted to contain domains associated with signal transduction, including Ca2+-, AKAP- and nucleotide-binding domains. This suggests that the spoke stalk is both a scaffold for signaling molecules and itself a transducer of signals. Moreover, in addition to the recently described HSP40 family member, a second spoke stalk protein is predicted to be a molecular chaperone, implying that there is a sophisticated mechanism for the assembly of this large complex. Among the 18 spoke proteins identified to date, at least 12 have apparent homologs in humans, indicating that the radial spoke has been conserved throughout evolution. The human genes encoding these proteins are candidates for causing primary ciliary dyskinesia, a severe inherited disease involving missing or defective axonemal structures, including the radial spokes

    Elite male Flat jockeys display lower bone density and lower resting metabolic rate than their female counterparts: implications for athlete welfare

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    To test the hypothesis that daily weight-making is more problematic to health in male compared with female jockeys, we compared the bone-density and resting metabolic rate (RMR) in weight-matched male and female Flat-jockeys. RMR (kcal.kg-1 lean mass) was lower in males compared with females as well as lower bone-density Z-scores at the hip and lumbar spine. Data suggest the lifestyle of male jockeys’ compromise health more severely than females, possibly due to making-weight more frequently

    Correction for \u3cem\u3eIC97 Is a Novel Intermediate Chain of I1 Dynein That Interacts with Tubulin and Regulates Interdoublet Sliding\u3c/em\u3e

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    Our goal is to understand the assembly and regulation of flagellar dyneins, particularly the Chlamydomonas inner arm dynein called I1 dynein. Here, we focus on the uncharacterized I1-dynein IC IC97. The IC97 gene encodes a novel IC without notable structural domains. IC97 shares homology with the murine lung adenoma susceptibility 1 (Las1) protein—a candidate tumor suppressor gene implicated in lung tumorigenesis. Multiple, independent biochemical assays determined that IC97 interacts with both α- and β-tubulin subunits within the axoneme. I1-dynein assembly mutants suggest that IC97 interacts with both the IC138 and IC140 subunits within the I1-dynein motor complex and that IC97 is part of a regulatory complex that contains IC138. Microtubule sliding assays, using axonemes containing I1 dynein but devoid of IC97, show reduced microtubule sliding velocities that are not rescued by kinase inhibitors, revealing a critical role for IC97 in I1-dynein function and control of dynein-driven motility

    Prospects for utilizing microbial consortia for lignin conversion

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    Naturally occurring microbial communities are able to decompose lignocellulosic biomass through the concerted production of a myriad of enzymes that degrade its polymeric components and assimilate the resulting breakdown compounds by members of the community. This process includes the conversion of lignin, the most recalcitrant component of lignocellulosic biomass and historically the most difficult to valorize in the context of a biorefinery. Although several fundamental questions on microbial conversion of lignin remain unanswered, it is known that some fungi and bacteria produce enzymes to break, internalize, and assimilate lignin-derived molecules. The interest in developing efficient biological lignin conversion approaches has led to a better understanding of the types of enzymes and organisms that can act on different types of lignin structures, the depolymerized compounds that can be released, and the products that can be generated through microbial biosynthetic pathways. It has become clear that the discovery and implementation of native or engineered microbial consortia could be a powerful tool to facilitate conversion and valorization of this underutilized polymer. Here we review recent approaches that employ isolated or synthetic microbial communities for lignin conversion to bioproducts, including the development of methods for tracking and predicting the behavior of these consortia, the most significant challenges that have been identified, and the possibilities that remain to be explored in this field

    Adoptive immunotherapy against allogeneic kidney grafts in dogs with stable hematopoietic trichimerism.

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    Dogs given nonmyeloablative conditioning and marrow grafts from 2 dog leukocyte antigen (DLA)-identical littermate donors developed stable trichimerism and stably accepted a subsequent kidney graft from one of the marrow donors without the need for immunosuppression. In this study, we used trichimeras to evaluate strategies for adoptive immunotherapy to solid tumors, using the kidney as a tumor surrogate. Three DLA-identical trichimeric recipients were established by simultaneously infusing marrow from 2 DLA-identical donor dogs into a DLA-identical recipient conditioned with 2 Gy of total body irradiation (TBI) and given a short course of postgraft immunosuppression. After stable hematopoietic engraftment was confirmed, a kidney was transplanted from 1 of the 2 marrow donors into each respective trichimeric recipient. Peripheral blood lymphocytes from each kidney donor were then used to sensitize the alternate marrow donor. The trichimeric recipients were given donor lymphocyte infusions (DLIs) from the sensitized dogs and monitored for chimerism, graft-versus-host disease (GVHD), and kidney rejection. After DLI, we observed both prompt rejection of the transplanted marrow and donor kidney and disappearance of corresponding hematopoietic chimerism. Presumably due to shared minor histocompatibility antigens, host chimerism also disappeared, and GVHD in skin, gut, and liver developed. The native kidneys, although exhibiting lymphocytic infiltration, remained functionally normal. This study demonstrates that under certain experimental conditions, the kidney--an organ ordinarily not involved in graft-versus-host reactions--can be targeted by sensitized donor lymphocytes

    Hematopoietic Cell Transplantation as Curative Therapy for Idiopathic Myelofibrosis, Advanced Polycythemia Vera, and Essential Thrombocythemia

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    AbstractA total of 104 patients, aged 18 to 70 years, with a diagnosis of chronic idiopathic myelofibrosis (CIMF), polycythemia vera (PV), or essential thrombocythemia (ET) with marrow fibrosis were transplanted from allogeneic (56 related and 45 unrelated) or syngeneic (n = 3) donors. Busulfan (BU) or total body irradiation (TBI)-based myeloablative conditioning regimens were used in 95 patients, and a nonmyeloablative regimen of fludarabine plus TBI was used in 9 patients. The source of stem cells was bone marrow in 43 patients and peripheral blood in 61 patients. A total of 63 patients were alive at a follow-up of 1.3–15.2 years (median, 5.3 years), for an estimated 7-year actuarial survival rate of 61%. Eleven patients had recurrent/persistent disease, of whom 8 died. Nonrelapse mortality was 34% at 5 years. Patients conditioned with targeted BU (plasma levels 800–900 ng/mL) plus cyclophosphamide (tBUCY) had a higher probability of survival (68%) than other patients. Dupriez score, platelet count, patient age, and comorbidity score were statistically significantly associated with mortality in univariate models. In a multivariable regression model, use of tBUCY (P = .03), high platelet count at transplantation (P = .01 for PV/ET; P = .39 for other diagnoses), younger patient age (P = .04), and decreased comorbidity score (P = .03) remained statistically significant for improved survival. Our findings show that hematopoietic cell transplantation offers potentially curative treatment for patients with ICMF, PV, or ET

    Colon biopsies for evaluation of acute graft-versus-host disease (A-GVHD) in allogeneic bone marrow transplant patients

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    BACKGROUND: Proper histomorphological interpretation of intestinal acute graft versus host disease (A-GVHD) associated with allogeneic bone marrow transplantation (BMT) is critical for clinical managaement. However, studies methodically evaluating different histomorphological features of A-GVHD are rare. METHODS: Colonic biopsies from 44 allogeneic BMT patients having biopsy-proven cutaneous A-GVHD were compared with colon biopsies from 48 negative controls. RESULTS: A-GVHD showed intra-cryptal apoptosis in 91% and pericryptal apoptosis in adjacent lamina propria in 70% (p < 0.002). Nonspecific apoptosis along the surface epithelium was observed in all groups with comparable frequency. The number of apoptotic cells in mucosa were approximately four times (5.3 per 10 HPF) the negative controls (p < 0.002) in A-GVHD group. 48% of cases with A-GVHD showed decreased number of lymphocytes in lamina propria. Some features, including intraepithelial lymphocytes in surface or crypt epithelium; and neutrophils, eosinophils, and edema in lamina propria, did not demonstrate significant difference in A-GVHD and negative controls. Pericryptal apoptosis, dilated crypts, irregular distribution of crypts, decreased lymphocytes, increased microvessel network, focal fibrosis, presence of muciphages, reactive changes in surface epithelium with mucin depletion, mucosal ulceration, and/or reduced mucosal thickness showed higher association with A-GVHD group. CONCLUSIONS: Intracyptal apoptosis is a reliable indicator of A-GVHD. Its diagnostic significance was improved if intracyptal apoptosis was associated with features which were observed more frequently in A-GVHD group as mentioned above

    Antimicrobial resistance among migrants in Europe: a systematic review and meta-analysis

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    BACKGROUND: Rates of antimicrobial resistance (AMR) are rising globally and there is concern that increased migration is contributing to the burden of antibiotic resistance in Europe. However, the effect of migration on the burden of AMR in Europe has not yet been comprehensively examined. Therefore, we did a systematic review and meta-analysis to identify and synthesise data for AMR carriage or infection in migrants to Europe to examine differences in patterns of AMR across migrant groups and in different settings. METHODS: For this systematic review and meta-analysis, we searched MEDLINE, Embase, PubMed, and Scopus with no language restrictions from Jan 1, 2000, to Jan 18, 2017, for primary data from observational studies reporting antibacterial resistance in common bacterial pathogens among migrants to 21 European Union-15 and European Economic Area countries. To be eligible for inclusion, studies had to report data on carriage or infection with laboratory-confirmed antibiotic-resistant organisms in migrant populations. We extracted data from eligible studies and assessed quality using piloted, standardised forms. We did not examine drug resistance in tuberculosis and excluded articles solely reporting on this parameter. We also excluded articles in which migrant status was determined by ethnicity, country of birth of participants' parents, or was not defined, and articles in which data were not disaggregated by migrant status. Outcomes were carriage of or infection with antibiotic-resistant organisms. We used random-effects models to calculate the pooled prevalence of each outcome. The study protocol is registered with PROSPERO, number CRD42016043681. FINDINGS: We identified 2274 articles, of which 23 observational studies reporting on antibiotic resistance in 2319 migrants were included. The pooled prevalence of any AMR carriage or AMR infection in migrants was 25·4% (95% CI 19·1-31·8; I2 =98%), including meticillin-resistant Staphylococcus aureus (7·8%, 4·8-10·7; I2 =92%) and antibiotic-resistant Gram-negative bacteria (27·2%, 17·6-36·8; I2 =94%). The pooled prevalence of any AMR carriage or infection was higher in refugees and asylum seekers (33·0%, 18·3-47·6; I2 =98%) than in other migrant groups (6·6%, 1·8-11·3; I2 =92%). The pooled prevalence of antibiotic-resistant organisms was slightly higher in high-migrant community settings (33·1%, 11·1-55·1; I2 =96%) than in migrants in hospitals (24·3%, 16·1-32·6; I2 =98%). We did not find evidence of high rates of transmission of AMR from migrant to host populations. INTERPRETATION: Migrants are exposed to conditions favouring the emergence of drug resistance during transit and in host countries in Europe. Increased antibiotic resistance among refugees and asylum seekers and in high-migrant community settings (such as refugee camps and detention facilities) highlights the need for improved living conditions, access to health care, and initiatives to facilitate detection of and appropriate high-quality treatment for antibiotic-resistant infections during transit and in host countries. Protocols for the prevention and control of infection and for antibiotic surveillance need to be integrated in all aspects of health care, which should be accessible for all migrant groups, and should target determinants of AMR before, during, and after migration. FUNDING: UK National Institute for Health Research Imperial Biomedical Research Centre, Imperial College Healthcare Charity, the Wellcome Trust, and UK National Institute for Health Research Health Protection Research Unit in Healthcare-associated Infections and Antimictobial Resistance at Imperial College London
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