305 research outputs found

    The Mass Function of Newly Formed Stars (Review)

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    The topic of the stellar "original mass function" has a nearly 50 year history,dating to the publication in 1955 of Salpeter's seminal paper. In this review I discuss the many more recent results that have emerged on the initial mass function (IMF), as it is now called, from studies over the last decade of resolved populations in star forming regions and young open clusters.Comment: 9 pages, 1 figure; to appear in "The Dense Instellar Medium in Galaxies -- 4'th Cologne-Bonn-Zermatt-Symposium" editted by S. Pfalzner, C. Kramer, C. Straubmeier and A. Heithausen, Springer-Verlag (2004

    Addressing Recruitment Challenges in the Engage-HU Trial in Young Children with Sickle Cell Disease

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    Background: Sickle cell disease (SCD) is a genetic disorder that causes significant medical and neurologic morbidity in children. Hydroxyurea (HU) is the primary medication used to prevent these complications. National Heart, Lung, and Blood Institute (NHLBI) guidelines recommend offering HU to children as young as 9 months of age with SCD (HbSS or HbSB0 thalassemia) using a shared decision-making approach. Although HU has proven efficacious it remains underutilized and caregivers report that they are not always actively involved in the decision to initiate this therapy. Reasons for limited HU uptake likely include lack of clinician knowledge and training and negative caregiver perceptions. Thus, we developed the Engage-HU trial as a novel approach to address HU utilization barriers. A critical consideration for this trial was that SCD primarily affects individuals of African and Hispanic/Latino descent. In these minority populations, intervention trials are sometimes terminated early because of recruitment difficulties related to mistrust of research, caregiver burden, and transportation issues. As such, the Engage-HU trial design included best-practice strategies for recruiting people of color in research. This study describes these strategies, the initial recruitment plan, preliminary recruitment outcomes and strategies, and our procedural adaptations. Study Design and Methods: Engage-HU is a randomized control trial (NCT03442114) to assess how clinicians can engage caregivers in a shared discussion that considers their values and preferences and includes evidence that supports HU. Engage-HU compares two dissemination methods for clinicians to facilitate shared decision-making with caregivers of young children with SCD: 1) the American Society of Hematology Pocket Guide, and 2) the HU Shared-Decision Making (H-SDM) Toolkit. The study aims to recruit 174 caregivers and evaluate the effectiveness of the dissemination methods on patient-centered outcomes (caregiver confidence in decision-making and perceptions of experiencing shared decision-making) as well as HU uptake and child health outcomes. Eligible children are aged 0 to 5 years, candidates for HU, and their caregiver has not made a decision about HU in the past 3 months. The trial is being conducted at 9 sites in the United States and uses a stepped-wedge design. Data will be analyzed based on the intent-to-treat principle. All participants will remain in the arm of the study to which they were randomized, regardless of whether or not they receive the assigned dissemination method. The primary endpoints are caregiver decisional uncertainty and caregiver perception of shared decision-making measured using validated tools. Data will be analyzed using a linear mixed effects regression model with a robust variance estimator and maximum likelihood estimation with observations clustered within site. The Engage-HU trial includes adaptations to increase recruitment such as tailored messaging, a relational recruitment approach, streamlined data collection, and a Stakeholder Advisory Committee. However, even with these adaptations, the first 6-months of the trial yielded lower than anticipated recruitment. Rather than terminate the trial or accept low enrollment, the research team implemented a series of recruitment strategies to address barriers including helping to improve research coordinator knowledge of the study purpose and adjusting no-show and follow-up procedures (e.g., calls to families after missed appointments and reminder calls before appointments). Site clinicians and clinic staff were provided with additional training so they could give more context about Engage-HU to caregivers and the study principal investigator led monthly "all coordinator" calls to provide support by sharing updates and experiences about successful recruitment. Implementation of these strategies resulted in triple the number of enrollments over the next 7-months compared to the previous 6-months (Table 1). Our goal in sharing this information is to provide lessons learned that can be implemented in future trials with the systematically underserved SCD population. It is also anticipated that methods described here may also inform clinical approaches to better engage caregivers of young children around critical clinical conversations, such as initiating medications like HU. Disclosures King: Magenta Therapeutics: Membership on an entity's Board of Directors or advisory committees; Bioline: Consultancy; RiverVest: Consultancy; Novimmune: Research Funding; Celgene: Consultancy; Tioma Therapuetics: Consultancy; Amphivena Therapeutics: Research Funding; WUGEN: Current equity holder in private company; Cell Works: Consultancy; Incyte: Consultancy. Smith-Whitley:Prime: Other: Education material; Celgene: Membership on an entity's Board of Directors or advisory committees; Global Blood Therapeutics: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees. Neumayr:Emmaus: Consultancy; Bayer: Consultancy; CTD Holdings: Consultancy; Pfizer: Consultancy; ApoPharma: Consultancy, Membership on an entity's Board of Directors or advisory committees; Micelle: Other: Site principal investigator; GBT: Other: Site principal investigator; PCORI: Other: site principal investigator; Novartis: Other: co-investigator; Bluebird Bio: Other: co-investigator; Sangamo Therapeutics: Other; Silarus: Other; Celgene: Other; La Jolla Pharmaceuticals: Other; Forma: Other; Imara: Other; National Heart, Lung, and Blood Institute: Other; Health Resources and Services Administration: Other; Centers for Disease Control and Prevention: Other; Seattle Children's Research: Other. Yates:Novartis: Research Funding. Thompson:Novartis: Consultancy, Honoraria, Research Funding; CRISPR/Vertex: Research Funding; BMS: Consultancy, Research Funding; Baxalta: Research Funding; Biomarin: Research Funding; bluebird bio, Inc.: Consultancy, Research Funding. </jats:sec

    Engaging Caregivers and Providers of Children With Sickle Cell Anemia in Shared Decision Making for Hydroxyurea: Protocol for a Multicenter Randomized Controlled Trial

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    BACKGROUND: Sickle cell anemia (SCA) is a genetic blood disorder that puts children at a risk of serious medical complications, early morbidity and mortality, and high health care utilization. Until recently, hydroxyurea was the only disease-modifying treatment for this life-threatening disease and has remained the only option for children younger than 5 years. Evidence-based guidelines recommend using a shared decision-making (SDM) approach for offering hydroxyurea to children with SCA (HbSS or HbS/Ξ²0 thalassemia) aged as early as 9 months. However, the uptake remains suboptimal, likely because caregivers lack information about hydroxyurea and have concerns about its safety and potential long-term side effects. Moreover, clinicians do not routinely receive training or tools, especially those that provide medical evidence and consider caregivers' preferences and values, to facilitate a shared discussion with caregivers. OBJECTIVE: The aim of this study is to understand how best to help parents of young children with sickle cell disease and their clinicians have a shared discussion about hydroxyurea (one that considers medical evidence and parent values and preferences). METHODS: We designed our study to compare the effectiveness of two methods for disseminating hydroxyurea guidelines to facilitate SDM: a clinician pocket guide (ie, usual care) and a clinician hydroxyurea SDM toolkit (H-SDM toolkit). Our primary outcomes are caregiver reports of decisional uncertainty and knowledge of hydroxyurea. The study also assesses the number of children (aged 0-5 years) who were offered and prescribed hydroxyurea and the resultant health outcomes. RESULTS: The Ethics Committee of the Cincinnati Children's Hospital Medical Center approved this study in November 2017. As of February 2021, we have enrolled 120 caregiver participants. CONCLUSIONS: The long-term objective of this study is to improve the quality of care for children with SCA. Using multicomponent dissemination methods developed in partnership with key stakeholders and designed to address barriers to high-quality care, caregivers of patients with SCA can make informed and shared decisions about their health. TRIAL REGISTRATION: ClinicalTrials.gov NCT03442114; https://clinicaltrials.gov/ct2/show/NCT03442114. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/27650

    Standards for the Characterization of Endurance in Resistive Switching Devices

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    Resistive switching (RS) devices are emerging electronic components that could have applications in multiple types of integrated circuits, including electronic memories, true random number generators, radiofrequency switches, neuromorphic vision sensors, and artificial neural networks. The main factor hindering the massive employment of RS devices in commercial circuits is related to variability and reliability issues, which are usually evaluated through switching endurance tests. However, we note that most studies that claimed high endurances >106 cycles were based on resistance versus cycle plots that contain very few data points (in many cases even <20), and which are collected in only one device. We recommend not to use such a characterization method because it is highly inaccurate and unreliable (i.e., it cannot reliably demonstrate that the device effectively switches in every cycle and it ignores cycle-to-cycle and device-to-device variability). This has created a blurry vision of the real performance of RS devices and in many cases has exaggerated their potential. This article proposes and describes a method for the correct characterization of switching endurance in RS devices; this method aims to construct endurance plots showing one data point per cycle and resistive state and combine data from multiple devices. Adopting this recommended method should result in more reliable literature in the field of RS technologies, which should accelerate their integration in commercial products

    Population based allele frequencies of disease associated polymorphisms in the Personalized Medicine Research Project

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    <p>Abstract</p> <p>Background</p> <p>There is a lack of knowledge regarding the frequency of disease associated polymorphisms in populations and population attributable risk for many populations remains unknown. Factors that could affect the association of the allele with disease, either positively or negatively, such as race, ethnicity, and gender, may not be possible to determine without population based allele frequencies.</p> <p>Here we used a panel of 51 polymorphisms previously associated with at least one disease and determined the allele frequencies within the entire Personalized Medicine Research Project population based cohort. We compared these allele frequencies to those in dbSNP and other data sources stratified by race. Differences in allele frequencies between self reported race, region of origin, and sex were determined.</p> <p>Results</p> <p>There were 19544 individuals who self reported a single racial category, 19027 or (97.4%) self reported white Caucasian, and 11205 (57.3%) individuals were female. Of the 11,208 (57%) individuals with an identifiable region of origin 8337 or (74.4%) were German.</p> <p>41 polymorphisms were significantly different between self reported race at the 0.05 level. Stratification of our Caucasian population by self reported region of origin revealed 19 polymorphisms that were significantly different (p = 0.05) between individuals of different origins. Further stratification of the population by gender revealed few significant differences in allele frequencies between the genders.</p> <p>Conclusions</p> <p>This represents one of the largest population based allele frequency studies to date. Stratification by self reported race and region of origin revealed wide differences in allele frequencies not only by race but also by region of origin within a single racial group. We report allele frequencies for our Asian/Hmong and American Indian populations; these two minority groups are not typically selected for population allele frequency detection. Population wide allele frequencies are important for the design and implementation of studies and for determining the relevance of a disease associated polymorphism for a given population.</p

    Targeted physiotherapy for patellofemoral joint osteoarthritis: A protocol for a randomised, single-blind controlled trial

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    <p>Abstract</p> <p>Background</p> <p>The patellofemoral joint (PFJ) is one compartment of the knee that is frequently affected by osteoarthritis (OA) and is a potent source of OA symptoms. However, there is a dearth of evidence for compartment-specific treatments for PFJ OA. Therefore, this project aims to evaluate whether a physiotherapy treatment, targeted to the PFJ, results in greater improvements in pain and physical function than a physiotherapy education intervention in people with symptomatic and radiographic PFJ OA.</p> <p>Methods</p> <p>90 people with PFJ OA (PFJ-specific history, signs and symptoms and radiographic evidence of PFJ OA) will be recruited from the community and randomly allocated into one of two treatments. A randomised controlled trial adhering to CONSORT guidelines will evaluate the efficacy of physiotherapy (8 individual sessions over 12 weeks, as well as a home exercise program 4 times/week) compared to a physiotherapist-delivered OA education control treatment (8 individual sessions over 12 weeks). Physiotherapy treatment will consist of (i) quadriceps muscle retraining; (ii) quadriceps and hip muscle strengthening; (iii) patellar taping; (iv) manual PFJ and soft tissue mobilisation; and (v) OA education. Resistance and dosage of exercises will be tailored to the participant's functional level and clinical state. Primary outcomes will be evaluated by a blinded examiner at baseline, 12 weeks and 9 months using validated and reliable pain, physical function and perceived global effect scales. All analyses will be conducted on an intention-to-treat basis using linear mixed regression models, including respective baseline scores as a covariate, subjects as a random effect, treatment condition as a fixed factor and the covariate by treatment interaction.</p> <p>Conclusion</p> <p>This RCT is targeting PFJ OA, an important sub-group of knee OA patients, with a specifically designed conservative intervention. The project's outcome will influence PFJ OA rehabilitation, with the potential to reduce the personal and societal burden of this increasing public health problem.</p> <p>Trial Registration</p> <p>Australia New Zealand Clinical Trials Registry ACTRN12608000288325</p

    Macrophage Migration Inhibitory Factor Antagonist Blocks the Development of Endometriosis In Vivo

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    Endometriosis, a disease of reproductive age women, is a major cause of infertility, menstrual disorders and pelvic pain. Little is known about its etiopathology, but chronic pelvic inflammation is a common feature in affected women. Beside symptomatic treatment of endometriosis-associated pain, only two main suboptimal therapeutic approaches (hormonal and invasive surgery) are generally recommended to patients and no specific targeted treatment is available. Our studies led to the detection of a marked increase in the expression of macrophage migration inhibitory factor (MIF) in the eutopic endometrium, the peripheral blood and the peritoneal fluid of women with endometriosis, and in early, vascularized and active endometriotic lesions. Herein, we developed a treatment model of endometriosis, where human endometrial tissue was first allowed to implant into the peritoneal cavity of nude mice, to assess in vivo the effect of a specific antagonist of MIF (ISO-1) on the progression of endometriosis and evaluate its efficacy as a potential therapeutic tool. Administration of ISO-1 led to a significant decline of the number, size and in situ dissemination of endometriotic lesions. We further showed that ISO-1 may act by significantly inhibiting cell adhesion, tissue remodeling, angiogenesis and inflammation as well as by altering the balance of pro- and anti-apoptotic factors. Actually, mice treatment with ISO-1 significantly reduced the expression of cell adhesion receptors αv and ß3 integrins (P<0.05), matrix metalloproteinases (MMP) 2 and 9 (P<0.05), vascular endothelial cell growth factor (VEGF) (P<0.01), interleukin 8 (IL8) (P<0.05), cyclooxygenease (COX)2 (P<0.001) and the anti-apoptotic protein Bcl2 (P<0.01), but significantly induced the expression of Bax (P<0.05), a potent pro-apoptotic protein. These data provide evidence that specific inhibition of MIF alters endometriotic tissue growth and progression in vivo and may represent a promising potential therapeutic avenue

    Adipose Tissue Deficiency and Chronic Inflammation in Diabetic Goto-Kakizaki Rats

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    Type 2 diabetes (T2DM) is a heterogeneous group of diseases that is progressive and involves multiple tissues. Goto-Kakizaki (GK) rats are a polygenic model with elevated blood glucose, peripheral insulin resistance, a non-obese phenotype, and exhibit many degenerative changes observed in human T2DM. As part of a systems analysis of disease progression in this animal model, this study characterized the contribution of adipose tissue to pathophysiology of the disease. We sacrificed subgroups of GK rats and appropriate controls at 4, 8, 12, 16 and 20 weeks of age and carried out a gene array analysis of white adipose tissue. We expanded our physiological analysis of the animals that accompanied our initial gene array study on the livers from these animals. The expanded analysis included adipose tissue weights, HbA1c, additional hormonal profiles, lipid profiles, differential blood cell counts, and food consumption. HbA1c progressively increased in the GK animals. Altered corticosterone, leptin, and adiponectin profiles were also documented in GK animals. Gene array analysis identified 412 genes that were differentially expressed in adipose tissue of GKs relative to controls. The GK animals exhibited an age-specific failure to accumulate body fat despite their relatively higher calorie consumption which was well supported by the altered expression of genes involved in adipogenesis and lipogenesis in the white adipose tissue of these animals, including Fasn, Acly, Kklf9, and Stat3. Systemic inflammation was reflected by chronically elevated white blood cell counts. Furthermore, chronic inflammation in adipose tissue was evident from the differential expression of genes involved in inflammatory responses and activation of natural immunity, including two interferon regulated genes, Ifit and Iipg, as well as MHC class II genes. This study demonstrates an age specific failure to accumulate adipose tissue in the GK rat and the presence of chronic inflammation in adipose tissue from these animals

    Effects of laterally wedged insoles on symptoms and disease progression in medial knee osteoarthritis: a protocol for a randomised, double-blind, placebo controlled trial

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    <p>Abstract</p> <p>Background</p> <p>Whilst laterally wedged insoles, worn inside the shoes, are advocated as a simple, inexpensive, non-toxic self-administered intervention for knee osteoarthritis (OA), there is currently limited evidence to support their use. The aim of this randomised, double-blind controlled trial is to determine whether laterally wedges insoles lead to greater improvements in knee pain, physical function and health-related quality of life, and slower structural disease progression as well as being more cost-effective, than control flat insoles in people with medial knee OA.</p> <p>Methods/Design</p> <p>Two hundred participants with painful radiographic medial knee OA and varus malalignment will be recruited from the community and randomly allocated to lateral wedge or control insole groups using concealed allocation. Participants will be blinded as to which insole is considered therapeutic. Blinded follow up assessment will be conducted at 12 months after randomisation. The outcome measures are valid and reliable measures recommended for OA clinical trials. Questionnaires will assess changes in pain, physical function and health-related quality-of-life. Magnetic resonance imaging will measure changes in tibial cartilage volume. To evaluate cost-effectiveness, participants will record the use of all health-related treatments in a log-book returned to the assessor on a monthly basis. To test the effect of the intervention using an intention-to-treat analysis, linear regression modelling will be applied adjusting for baseline outcome values and other demographic characteristics.</p> <p>Discussion</p> <p>Results from this trial will contribute to the evidence regarding the effectiveness of laterally wedged insoles for the management of medial knee OA.</p> <p>Trial registration</p> <p>ACTR12605000503628; NCT00415259.</p
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