79 research outputs found

    The maize brown midrib6 (bm6) mutation encodes a functional GTP Cyclohydrolase1

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    Brown midrib mutations in maize (Zea mays L.) and sorghum (Sorghum bicolor L.) alter lignin composition and enhance cell wall digestibility. These mutations are prime candidates for silage breeding. Six brown midrib mutants are currently known, brown midrib1 (bm1) to brown midrib6 (bm6). The bm1 and bm3 mutations are being used commercially for silage. The underlying genes responsible for five of the six bm mutations in maize (bm1, bm2, bm3, bm4, and bm5) are known. Chen and co-workers (2012) characterized the bm6 mutation, demonstratingthat bm6 increases cell wall digestibility and physically mapped bm6 within a 180 kilobase region on chromosome 2. The present investigation utilized map-based cloning to identify the candidate gene responsible for the bm6 phenotype as GTP Cyclohydrolase1 (GCH1) and validated the candidate gene through reverse genetics. Orthologs of bm6 include at least one paralogous gene in maize on chromosome 10 and various homologs in other grasses and dicots. The discovery that GCH1 is  responsible for the maize bm6 phenotype suggests that GCH1 plays a role in the tetrahydrofolate biosynthetic process

    Potential Cost-effectiveness of Early Identification of Hospital-acquired Infection in Critically Ill Patients

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    Limitations in methods for the rapid diagnosis of hospital-acquired infections often delay initiation of effective antimicrobial therapy. New diagnostic approaches offer potential clinical and cost-related improvements in the management of these infections. We developed a decision modeling framework to assess the potential cost-effectiveness of a rapid biomarker assay to identify hospital-acquired infection in high-risk patients earlier than standard diagnostic testing. The framework includes parameters representing rates of infection, rates of delayed appropriate therapy, and impact of delayed therapy on mortality, along with assumptions about diagnostic test characteristics and their impact on delayed therapy and length of stay. Parameter estimates were based on contemporary, published studies and supplemented with data from a four-site, observational, clinical study. Extensive sensitivity analyses were performed. The base-case analysis assumed 17.6% of ventilated patients and 11.2% of nonventilated patients develop hospital-acquired infection and that 28.7% of patients with hospital-acquired infection experience delays in appropriate antibiotic therapy with standard care. We assumed this percentage decreased by 50% (to 14.4%) among patients with true-positive results and increased by 50% (to 43.1%) among patients with false-negative results using a hypothetical biomarker assay. Cost of testing was set at 110/d.Inthebasecaseanalysis,amongventilatedpatients,dailydiagnostictestingstartingonadmissionreducedinpatientmortalityfrom12.3to11.9110/d. In the base-case analysis, among ventilated patients, daily diagnostic testing starting on admission reduced inpatient mortality from 12.3 to 11.9% and increased mean costs by 1,640 per patient, resulting in an incremental cost-effectiveness ratio of 21,389perlifeyearsaved.Amongnonventilatedpatients,inpatientmortalitydecreasedfrom7.3to7.121,389 per life-year saved. Among nonventilated patients, inpatient mortality decreased from 7.3 to 7.1% and costs increased by 1,381 with diagnostic testing. The resulting incremental cost-effectiveness ratio was 42,325perlifeyearsaved.Thresholdanalysesrevealedtheprobabilitiesofdevelopinghospitalacquiredinfectioninventilatedandnonventilatedpatientscouldbeaslowas8.4and9.842,325 per life-year saved. Threshold analyses revealed the probabilities of developing hospital-acquired infection in ventilated and nonventilated patients could be as low as 8.4 and 9.8%, respectively, to maintain incremental cost-effectiveness ratios less than 50,000 per life-year saved. Development and use of serial diagnostic testing that reduces the proportion of patients with delays in appropriate antibiotic therapy for hospital-acquired infections could reduce inpatient mortality. The model presented here offers a cost-effectiveness framework for future test development

    Long-term impact of four different strategies for delivering an on-line curriculum about herbs and other dietary supplements

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    BACKGROUND: Previous research has shown that internet education can lead to short-term improvements in clinicians' knowledge, confidence and communication practices. We wished to better understand the duration of these improvements and whether different curriculum delivery strategies differed in affecting these improvements. METHODS: As previously described, we conducted a randomized control trial comparing four different strategies for delivering an e-curriculum about herbs and other dietary supplements (HDS) to clinicians. The four strategies were delivering the curriculum by: a) email over 10 weeks; b) email within one week; c) web-site over 10 weeks; d) web-site within one week. Participants were surveyed at baseline, immediately after the course and 6–10 months after completing the course (long-term). Long-term outcomes focused on clinicians' knowledge, confidence and communication practices. RESULTS: Of the 780 clinicians who completed the course, 385 (49%) completed the long-term survey. Completers and non-completers of the long-term survey had similar demographics and professional characteristics at baseline. There were statistically significant improvements from baseline to long-term follow-up in knowledge, confidence and communication practices; these improvements did not differ by curriculum delivery strategy. Knowledge scores improved from 67.7 ± 10.3 at baseline to 78.8 ± 12.3 at long-term follow-up (P < 0.001). Confidence scores improved from 53.7 ± 17.8 at baseline to 66.9 ± 12.0 at long term follow-up (P < 0.001); communication scores improved from 2.6 ± 1.9 at baseline to 3.6 ± 2.1 (P < 0.001) at long-term follow-up. CONCLUSION: This e- curriculum led to significant and sustained improvements in clinicians' expertise about HDS regardless of the delivery strategy. Future studies should compare the impact of required vs. elective courses and self-reported vs. objective measures of behavior change

    Reticulocytes in donor blood units enhance red blood cell alloimmunization

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    Although red blood cell (RBC) transfusions save lives, some patients develop clinically-significant alloantibodies against donor blood group antigens, which then have adverse effects in multiple clinical settings. Few effective measures exist to prevent RBC alloimmunization and/or eliminate alloantibodies in sensitized patients. Donor-related factors may influence alloimmunization; thus, there is an unmet clinical need to identify which RBC units are immunogenic. Repeat volunteer blood donors and donors on iron supplements have elevated reticulocyte counts compared to healthy non-donors. Early reticulocytes retain mitochondria and other components, which may act as danger signals in immune responses. Herein, we tested whether reticulocytes in donor RBC units could enhance RBC alloimmunization. Using a murine model, we demonstrate that transfusing donor RBC units with increased reticulocyte frequencies dose-dependently increased RBC alloimmunization rates and alloantibody levels. Transfusing reticulocyte-rich RBC units was associated with increased RBC clearance from the circulation and a robust proinflammatory cytokine response. As compared to previously reported post-transfusion RBC consumption patterns, erythrophagocytosis from reticulocyte-rich units was increasingly performed by splenic B cells. These data suggest that reticulocytes in a donated RBC unit impact the quality of blood transfused, are targeted to a distinct compartment, and may be an underappreciated risk factor for RBC alloimmunization

    MicroRNA-1 is a candidate tumor suppressor and prognostic marker in human prostate cancer

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    We previously reported that miR-1 is among the most consistently down-regulated miRs in primary human prostate tumors. In this follow-up study, we further corroborated this finding in an independent data set and made the novel observation that miR-1 expression is further reduced in distant metastasis and is a candidate predictor of disease recurrence. Moreover, we performed in vitro experiments to explore the tumor suppressor function of miR-1. Cell-based assays showed that miR-1 is epigenetically silenced in human prostate cancer. Overexpression of miR-1 in these cells led to growth inhibition and down-regulation of genes in pathways regulating cell cycle progression, mitosis, DNA replication/repair and actin dynamics. This observation was further corroborated with protein expression analysis and 3′-UTR-based reporter assays, indicating that genes in these pathways are either direct or indirect targets of miR-1. A gene set enrichment analysis revealed that the miR-1-mediated tumor suppressor effects are globally similar to those of histone deacetylase inhibitors. Lastly, we obtained preliminary evidence that miR-1 alters the cellular organization of F-actin and inhibits tumor cell invasion and filipodia formation. In conclusion, our findings indicate that miR-1 acts as a tumor suppressor in prostate cancer by influencing multiple cancer-related processes and by inhibiting cell proliferation and motility

    CD74 is expressed in a subset of pediatric acute myeloid leukemia patients and is a promising target for therapy: a report from the Children’s Oncology Group

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    As curative therapies for pediatric AML remain elusive, identifying potential new treatment targets is vital. We assessed the cell surface expression of CD74, also known as the MHC-II invariant chain, by multidimensional flow cytometry in 973 patients enrolled in the Children’s Oncology Group AAML1031 clinical trial. 38% of pediatric AML patients expressed CD74 at any level and a comparison to normal hematopoietic cells revealed a subset with increased expression relative to normal myeloid progenitor cells. Pediatric AML patients expressing high intensity CD74 typically had an immature immunophenotype and an increased frequency of lymphoid antigen expression. Increased CD74 expression was associated with older patients with lower WBC and peripheral blood blast counts, and was enriched for t(8;21), trisomy 8, and CEBPA mutations. Overall, high CD74 expression was associated with low-risk status, however 26% of patients were allocated to high-risk protocol status and 5-year event free survival was 53%, indicating that a significant number of high expressing patients had poor outcomes. In vitro pre-clinical studies indicate that anti-CD74 therapy demonstrates efficacy against AML cells but has little impact on normal CD34+ cells. Together, we demonstrate that CD74 is expressed on a subset of pediatric AMLs at increased levels compared to normal hematopoietic cells and is a promising target for therapy in expressing patients. Given that nearly half of patients expressing CD74 at high levels experience an adverse event within 5 years, and the availability of CD74 targeting drugs, this represents a promising line of therapy worthy of additional investigation

    Impact of COVID-19 on cardiovascular testing in the United States versus the rest of the world

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    Objectives: This study sought to quantify and compare the decline in volumes of cardiovascular procedures between the United States and non-US institutions during the early phase of the coronavirus disease-2019 (COVID-19) pandemic. Background: The COVID-19 pandemic has disrupted the care of many non-COVID-19 illnesses. Reductions in diagnostic cardiovascular testing around the world have led to concerns over the implications of reduced testing for cardiovascular disease (CVD) morbidity and mortality. Methods: Data were submitted to the INCAPS-COVID (International Atomic Energy Agency Non-Invasive Cardiology Protocols Study of COVID-19), a multinational registry comprising 909 institutions in 108 countries (including 155 facilities in 40 U.S. states), assessing the impact of the COVID-19 pandemic on volumes of diagnostic cardiovascular procedures. Data were obtained for April 2020 and compared with volumes of baseline procedures from March 2019. We compared laboratory characteristics, practices, and procedure volumes between U.S. and non-U.S. facilities and between U.S. geographic regions and identified factors associated with volume reduction in the United States. Results: Reductions in the volumes of procedures in the United States were similar to those in non-U.S. facilities (68% vs. 63%, respectively; p = 0.237), although U.S. facilities reported greater reductions in invasive coronary angiography (69% vs. 53%, respectively; p < 0.001). Significantly more U.S. facilities reported increased use of telehealth and patient screening measures than non-U.S. facilities, such as temperature checks, symptom screenings, and COVID-19 testing. Reductions in volumes of procedures differed between U.S. regions, with larger declines observed in the Northeast (76%) and Midwest (74%) than in the South (62%) and West (44%). Prevalence of COVID-19, staff redeployments, outpatient centers, and urban centers were associated with greater reductions in volume in U.S. facilities in a multivariable analysis. Conclusions: We observed marked reductions in U.S. cardiovascular testing in the early phase of the pandemic and significant variability between U.S. regions. The association between reductions of volumes and COVID-19 prevalence in the United States highlighted the need for proactive efforts to maintain access to cardiovascular testing in areas most affected by outbreaks of COVID-19 infection

    Dissecting the Shared Genetic Architecture of Suicide Attempt, Psychiatric Disorders, and Known Risk Factors

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    Background Suicide is a leading cause of death worldwide, and nonfatal suicide attempts, which occur far more frequently, are a major source of disability and social and economic burden. Both have substantial genetic etiology, which is partially shared and partially distinct from that of related psychiatric disorders. Methods We conducted a genome-wide association study (GWAS) of 29,782 suicide attempt (SA) cases and 519,961 controls in the International Suicide Genetics Consortium (ISGC). The GWAS of SA was conditioned on psychiatric disorders using GWAS summary statistics via multitrait-based conditional and joint analysis, to remove genetic effects on SA mediated by psychiatric disorders. We investigated the shared and divergent genetic architectures of SA, psychiatric disorders, and other known risk factors. Results Two loci reached genome-wide significance for SA: the major histocompatibility complex and an intergenic locus on chromosome 7, the latter of which remained associated with SA after conditioning on psychiatric disorders and replicated in an independent cohort from the Million Veteran Program. This locus has been implicated in risk-taking behavior, smoking, and insomnia. SA showed strong genetic correlation with psychiatric disorders, particularly major depression, and also with smoking, pain, risk-taking behavior, sleep disturbances, lower educational attainment, reproductive traits, lower socioeconomic status, and poorer general health. After conditioning on psychiatric disorders, the genetic correlations between SA and psychiatric disorders decreased, whereas those with nonpsychiatric traits remained largely unchanged. Conclusions Our results identify a risk locus that contributes more strongly to SA than other phenotypes and suggest a shared underlying biology between SA and known risk factors that is not mediated by psychiatric disorders.Peer reviewe

    Contested Industry Dynamics: New Directions in Legitimacy Research

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    This article comments on the article "Contested Industry Dynamics," by Tiffany L. Galvin, Marc J. Ventresca, and Bryant A. Hudson, published in the present issue of the journal "International Studies of Management & Organization." Given the lack of contextuality characteristic of ecological research, and that institutional theory only recently has focused on issues of institutional change, the article by Galvin, Ventresca, and Hudson offers a fresh and needed complement to evolutionary and institutional research in organization theory. Moreover, the focus on the cognitive elements and market stories as enablers and obstacles of industry-wide evolutionary processes links this manuscript to research of belief systems. The two industries studied, tobacco and gambling, are industries with a prime interest to attract consumer desire for physical and mental stimulation. Gambling is a cultural phenomenon that is driven by individuals' lust for risk taking and playing, whereas tobacco use is driven by both physical and psychological phenomena. The evolution of tobacco and gambling industries vividly illustrates the importance of the institutional environment on firm survival
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