666 research outputs found

    CO\u3csub\u3e2\u3c/sub\u3e-Fixing One-Carbon Metabolism in a Cellulose-Degrading Bacterium \u3cem\u3eClostridium thermocellum\u3c/em\u3e

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    Clostridium thermocellum can ferment cellulosic biomass to formate and other end products, including CO2. This organism lacks formate dehydrogenase (Fdh), which catalyzes the reduction of CO2 to formate. However, feeding the bacterium 13C-bicarbonate and cellobiose followed by NMR analysis showed the production of 13C-formate in C. thermocellum culture, indicating the presence of an uncharacterized pathway capable of converting CO2 to formate. Combining genomic and experimental data, we demonstrated that the conversion of CO2 to formate serves as a CO2 entry point into the reductive one-carbon (C1) metabolism, and internalizes CO2 via two biochemical reactions: the reversed pyruvate: ferredoxin oxidoreductase (rPFOR), which incorporates CO2 using acetyl-CoA as a substrate and generates pyruvate, and pyruvate- formate lyase (PFL) converting pyruvate to formate and acetyl-CoA. We analyzed the labeling patterns of proteinogenic amino acids in individual deletions of all five putative PFOR mutants and in a PFL deletion mutant. We identified two enzymes acting as rPFOR, confirmed the dual activities of rPFOR and PFL crucial for CO2 uptake, and provided physical evidence of a distinct in vivo “rPFOR-PFL shunt” to reduce CO2 to formate while circumventing the lack of Fdh. Such a pathway precedes CO2 fixation via the reductive C1 metabolic pathway in C. thermocellum. These findings demonstrated the metabolic versatility of C. thermocellum, which is thought of as primarily a cellulosic heterotroph but is shown here to be endowed with the ability to fix CO2 as well

    Genetic Risk Score Predicting Risk of Rheumatoid Arthritis Phenotypes and Age of Symptom Onset

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    Cumulative genetic profiles can help identify individuals at high-risk for developing RA. We examined the impact of 39 validated genetic risk alleles on the risk of RA phenotypes characterized by serologic and erosive status.We evaluated single nucleotide polymorphisms at 31 validated RA risk loci and 8 Human Leukocyte Antigen alleles among 542 Caucasian RA cases and 551 Caucasian controls from Nurses' Health Study and Nurses' Health Study II. We created a weighted genetic risk score (GRS) and evaluated it as 7 ordinal groups using logistic regression (adjusting for age and smoking) to assess the relationship between GRS group and odds of developing seronegative (RF- and CCP-), seropositive (RF+ or CCP+), erosive, and seropositive, erosive RA phenotypes. In separate case only analyses, we assessed the relationships between GRS and age of symptom onset. In 542 RA cases, 317 (58%) were seropositive, 163 (30%) had erosions and 105 (19%) were seropositive with erosions. Comparing the highest GRS risk group to the median group, we found an OR of 1.2 (95% CI = 0.8-2.1) for seronegative RA, 3.0 (95% CI = 1.9-4.7) for seropositive RA, 3.2 (95% CI = 1.8-5.6) for erosive RA, and 7.6 (95% CI = 3.6-16.3) for seropositive, erosive RA. No significant relationship was seen between GRS and age of onset.Results suggest that seronegative and seropositive/erosive RA have different genetic architecture and support the importance of considering RA phenotypes in RA genetic studies

    Thromboprophylaxis Is Associated With Reduced Post-hospitalization Venous Thromboembolic Events in Patients With Inflammatory Bowel Diseases

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    Background & Aims Patients with inflammatory bowel diseases (IBDs) have increased risk for venous thromboembolism (VTE); those who require hospitalization have particularly high risk. Few hospitalized patients with IBD receive thromboprophylaxis. We analyzed the frequency of VTE after IBD-related hospitalization, risk factors for post-hospitalization VTE, and the efficacy of prophylaxis in preventing post-hospitalization VTE. Methods In a retrospective study, we analyzed data from a multi-institutional cohort of patients with Crohn's disease or ulcerative colitis and at least 1 IBD-related hospitalization. Our primary outcome was a VTE event. All patients contributed person-time from the date of the index hospitalization to development of VTE, subsequent hospitalization, or end of follow-up. Our main predictor variable was pharmacologic thromboprophylaxis. Cox proportional hazard models adjusting for potential confounders were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs). Results From a cohort of 2788 patients with at least 1 IBD-related hospitalization, 62 patients developed VTE after discharge (2%). Incidences of VTE at 30, 60, 90, and 180 days after the index hospitalization were 3.7/1000, 4.1/1000, 5.4/1000, and 9.4/1000 person-days, respectively. Pharmacologic thromboprophylaxis during the index hospital stay was associated with a significantly lower risk of post-hospitalization VTE (HR, 0.46; 95% CI, 0.22–0.97). Increased numbers of comorbidities (HR, 1.30; 95% CI, 1.16–1.47) and need for corticosteroids before hospitalization (HR, 1.71; 95% CI, 1.02–2.87) were also independently associated with risk of VTE. Length of hospitalization or surgery during index hospitalization was not associated with post-hospitalization VTE. Conclusions Pharmacologic thromboprophylaxis during IBD-related hospitalization is associated with reduced risk of post-hospitalization VTE.National Institutes of Health (U.S.) (U54-LM008748

    The Relation of FIMR Programs and Other Perinatal Systems Initiatives with Maternal and Child Health Activities in the Community

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    Objectives : To evaluate the association of the presence of a fetal and infant mortality review (FIMR) program, other perinatal systems initiative (PSI), or both in a community with the performance of essential maternal and child health (MCH) services by local health departments (LHDs). Methods : Data were obtained from telephone interviews with professionals from LHDs across the United States. Logistic regression was used to estimate the odds of a LHD conducting each essential MCH service in communities with and without FIMR programs or with and without PSIs, adjusted for geographic area. Results : Of the 193 communities in the sample, 41 had only a FIMR program, 36 had only a PSI, 47 had both programs, and 69 had neither. The presence of a FIMR was related to greater performance of essential MCH services in LHDs in six areas: data assessment and analysis; client services and access; quality assurance and improvement; community partnerships and mobilization; policy development; and enhancement of capacity of the health care work force. Similar findings were noted for the same broad essential services for PSIs. The comparisons of LHDs in FIMR and non-FIMR communities, however, showed greater involvement of communities with a FIMR program in essential MCH services related to data collection and quality assurance than were found for comparisons of LHDs in communities with and without a PSI. The presence of a PSI was uniquely associated with conducting needs assessments for pregnant women and infants, participation in coalitions for infants, promoting access for uninsured women to private providers and involving local officials and agencies in health plans for both populations. When both programs were present, LHDs had a greater odds of engaging in essential MCH services related to assessment and monitoring of the health of the population, reporting on progress in meeting the health needs of pregnant women and infants, and presenting data to local political officials than when either program alone was in the community. Conclusions : Local health departments in communities with FIMR programs or PSIs appear to be more likely to conduct essential MCH services in the community. Some of these relations are unique to FIMR, particularly for data collection and quality assurance services, and some are unique to PSIs, for example those that involve interaction with other community agencies or groups. Performance of the essential MCH services also appears to be enhanced when both a FIMR program and a PSI are present in the community.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/45329/1/10995_2004_Article_496297.pd

    Improving Case Definition of CrohnĘĽs Disease and Ulcerative Colitis in Electronic Medical Records Using Natural Language Processing

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    available in PMC 2014 June 01Background: Previous studies identifying patients with inflammatory bowel disease using administrative codes have yielded inconsistent results. Our objective was to develop a robust electronic medical record–based model for classification of inflammatory bowel disease leveraging the combination of codified data and information from clinical text notes using natural language processing. Methods: Using the electronic medical records of 2 large academic centers, we created data marts for Crohn’s disease (CD) and ulcerative colitis (UC) comprising patients with ≥1 International Classification of Diseases, 9th edition, code for each disease. We used codified (i.e., International Classification of Diseases, 9th edition codes, electronic prescriptions) and narrative data from clinical notes to develop our classification model. Model development and validation was performed in a training set of 600 randomly selected patients for each disease with medical record review as the gold standard. Logistic regression with the adaptive LASSO penalty was used to select informative variables. Results: We confirmed 399 CD cases (67%) in the CD training set and 378 UC cases (63%) in the UC training set. For both, a combined model including narrative and codified data had better accuracy (area under the curve for CD 0.95; UC 0.94) than models using only disease International Classification of Diseases, 9th edition codes (area under the curve 0.89 for CD; 0.86 for UC). Addition of natural language processing narrative terms to our final model resulted in classification of 6% to 12% more subjects with the same accuracy. Conclusions: Inclusion of narrative concepts identified using natural language processing improves the accuracy of electronic medical records case definition for CD and UC while simultaneously identifying more subjects compared with models using codified data alone.National Institutes of Health (U.S.) (NIH U54-LM008748)American Gastroenterological AssociationNational Institutes of Health (U.S.) (NIH K08 AR060257)Beth Isreal Deaconess Medical Center (Katherine Swan Ginsburg Fund)National Institutes of Health (U.S.) (NIH R01-AR056768)Burroughs Wellcome Fund (Career Award for Medical Scientists)National Institutes of Health (U.S.) (NIH U01-GM092691)National Institutes of Health (U.S.) (NIH R01-AR059648

    Psychiatric co-morbidity is associated with increased risk of surgery in Crohn's disease

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    Psychiatric co-morbidity, in particular major depression and anxiety, is common in patients with Crohn's disease (CD) and ulcerative colitis (UC). Prior studies examining this may be confounded by the co-existence of functional bowel symptoms. Limited data exist examining an association between depression or anxiety and disease-specific endpoints such as bowel surgery.National Institutes of Health (U.S.) (NIH U54-LM008748)American Gastroenterological AssociationNational Institutes of Health (U.S.) (NIH K08 AR060257)Beth Isreal Deaconess Medical Center (Katherine Swan Ginsburg Fund)National Institutes of Health (U.S.) (NIH R01-AR056768)National Institutes of Health (U.S.) (NIH U01-GM092691)National Institutes of Health (U.S.) (NIH R01-AR059648)Burroughs Wellcome Fund (Career Award for Medical Scientists)National Institutes of Health (U.S.) (NIH K24 AR052403)National Institutes of Health (U.S.) (NIH P60 AR047782)National Institutes of Health (U.S.) (NIH R01 AR049880
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