231 research outputs found

    Diagnostic Potential of the NMDA Receptor Peptide Assay for Acute Ischemic Stroke

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    Background The acute assessment of patients with suspected ischemic stroke remains challenging. The use of brain biomarker assays may improve the early diagnosis of ischemic stroke. The main goal of the study was to evaluate whether the NR2 peptide, a product of the proteolytic degradation of N-methyl-D-aspartate (NMDA) receptors, can differentiate acute ischemic stroke (IS) from stroke mimics and persons with vascular risk factors/healthy controls. A possible correlation between biomarker values and lesion sizes was investigated as the secondary objective. Methods and Findings A total of 192 patients with suspected stroke who presented within 72 h of symptom onset were prospectively enrolled. The final diagnosis was determined based on clinical observations and radiological findings. Additionally gender- and age-matched healthy controls (n = 52) and persons with controlled vascular risk factors (n = 48) were recruited to compare NR2 peptide levels. Blinded plasma was assayed by rapid magnetic particles (MP) ELISA for NR2 peptide within 30 min and results for different groups compared using univariate and multivariate statistical analyses. There was a clinical diagnosis of IS in 101 of 192 (53%) and non-stroke in 91 (47%) subjects. The non-stroke group included presented with acute stroke symptoms who had no stroke (n = 71) and stroke mimics (n = 20). The highest NR2 peptide elevations where found in patients with IS that peaked at 12 h following symptom onset. When the biomarker cut off was set at 1.0 ug/L, this resulted in a sensitivity of 92% and a specificity of 96% to detect IS. A moderate correlation (rs = 0.73) between NR2 peptide values and acute ischemic cortical lesions (\u3c200 \u3emL) was found. Conclusions This study suggests that the NR2 peptide may be a brain specific biomarker to diagnose acute IS and may allow the differentiation of IS from stroke mimics and controls. Additional larger scale clinical validation studies are required

    Primary care physicians are under-testing for celiac disease in patients with iron deficiency anemia: Results of a national survey

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    BACKGROUND: Iron deficiency anemia (IDA) is a common extra-intestinal manifestation of celiac disease (CD). Little is known about the frequency with which primary care physicians (PCPs) test for CD in patients with IDA. We aimed to describe how PCPs approach testing for CD in asymptomatic patients with IDA. METHODS: We electronically distributed a survey to PCPs who are members of the American College of Physicians. Respondents were asked whether they would test for CD (serologic testing, refer for esophagogastroduodenoscopy [EGD], or refer to GI) in hypothetical patients with new IDA, including: (1) a young Caucasian man, (2) a premenopausal Caucasian woman, (3) an elderly Caucasian man, and (4) a young African American man. These scenarios were chosen to assess for differences in testing for CD based on age, gender, and race. Multivariable logistic regression was used to identify independent predictors of testing. RESULTS: Testing for CD varied significantly according to patient characteristics, with young Caucasian men being the most frequently tested (61% of respondents reporting they would perform serologic testing in this subgroup (p CONCLUSIONS: PCPs are under-testing for CD in patients with IDA, regardless of age, gender, race, or post-menopausal status. The majority of PCPs surveyed reported they do not strictly adhere to established guidelines regarding a confirmatory duodenal biopsy in a patient with positive serology for CD

    Alteration of intracellular cysteine and glutathione levels in alveolar macrophages and lymphocytes by diesel exhaust particle exposure.

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    The purpose of this study was to characterize the effects of diesel exhaust particles (DEP) on thiol regulation in alveolar macrophages (AM) and lymphocytes. We obtained AM and lymph node (thymic and tracheal) cells (LNC) (at different time points) from rats exposed intratracheally to DEP (5 mg/kg) or saline, and measured inflammatory markers, thiol levels, and glutathione reductase (GSH-R) activity. DEP exposure produced significant increases in neutrophils, lactate dehydrogenase, total protein, and albumin content in the lavage fluid. AM from DEP-exposed rats showed a time-dependent increase in intracellular cysteine (CYSH) and GSH. In LNC the intracellular GSH reached peak level by 24 hr, declining toward control levels by 72 hr after exposure. LNC-CYSH and AM-CYSH and GSH were increased at both 24 and 72 hr. Both Sprague-Dawley and Brown Norway rats showed similar trends of responses to DEP exposure as per measurement of the inflammatory markers and thiol changes. AM and, to a lesser degree, LNC were both active in cystine uptake. The DEP exposure stimulated GSH-R activity and increased the conversion of cystine to CYSH in both cell types. The intracellular level of GSH in DEP-exposed AM was moderately increased compared with the saline control, and was further augmented when cells were incubated with cystine. In contrast, the intracellular level of GSH in DEP-exposed LNC was significantly reduced despite the increased CYSH level and GSH-R activity when these cells were cultured for 16 hr. DEP absorbed 23-31% of CYSH, cystine, and GSH, and only 8% of glutathione disulfide when incubated in cell free media. These results indicate that DEP exposure caused lung inflammation and affected thiol levels in both AM and LNC

    Alteration of pulmonary immunity to Listeria monocytogenes by diesel exhaust particles (DEPs). I. Effects of DEPs on early pulmonary responses.

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    It has been hypothesized that diesel exhaust particles (DEPs) aggravate pulmonary bacterial infection by both innate and cell-mediated immune mechanisms. To test this hypothesis, we investigated the effects of DEP exposure on the functions of alveolar macrophages (AMs) and lymphocytes from lung-draining lymph nodes using a rat Listeria monocytogenes infection model. In the present study, we focused on the effects of DEP exposure on AM functions, including phagocytic activity and secretion of proinflammatory cytokines. The Listeria infection model was characterized by an increase in neutrophil count, albumin content, and acellular lactate dehydrogenase activity in the bronchoalveolar lavage (BAL) fluid at 3 and 7 days postinfection. Short-term DEP inhalation (50 and 100 mg/m(3), 4 hr) resulted in a dose-dependent suppression of lung clearance of Listeria, with the highest bacteria count occurring at day 3. This aggravated bacterial infection was consistent with the inhibitory effect of DEPs on macrophage functions. DEPs suppressed phagocytosis and Listeria-induced basal secretion of interleukin-1ss (IL-1ss) and IL-12 by AMs in a dose-dependent manner. The amount of IL-1ss and IL-12 in the BAL fluid was also reduced by DEP exposure. In addition, DEPs decreased Listeria-induced lipopolysaccharide-stimulated secretion of tumor necrosis factor-alpha (TNF-alpha), IL-1ss, and IL-12 from AMs. These results suggest that DEPs retard bacterial clearance by inhibiting AM phagocytosis and weaken the innate immunity by inhibiting AM secretion of IL-1ss and TNF-alpha. DEPs may also suppress cell-mediated immunity by inhibiting AM secretion of IL-12, a key cytokine for the initiation of T helper type 1 cell development in Listeria infection

    Functional and Transcriptional Characterization of Human Embryonic Stem Cell-Derived Endothelial Cells for Treatment of Myocardial Infarction

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    BACKGROUND: Differentiation of human embryonic stem cells into endothelial cells (hESC-ECs) has the potential to provide an unlimited source of cells for novel transplantation therapies of ischemic diseases by supporting angiogenesis and vasculogenesis. However, the endothelial differentiation efficiency of the conventional embryoid body (EB) method is low while the 2-dimensional method of co-culturing with mouse embryonic fibroblasts (MEFs) require animal product, both of which can limit the future clinical application of hESC-ECs. Moreover, to fully understand the beneficial effects of stem cell therapy, investigators must be able to track the functional biology and physiology of transplanted cells in living subjects over time. METHODOLOGY: In this study, we developed an extracellular matrix (ECM) culture system for increasing endothelial differentiation and free from contaminating animal cells. We investigated the transcriptional changes that occur during endothelial differentiation of hESCs using whole genome microarray, and compared to human umbilical vein endothelial cells (HUVECs). We also showed functional vascular formation by hESC-ECs in a mouse dorsal window model. Moreover, our study is the first so far to transplant hESC-ECs in a myocardial infarction model and monitor cell fate using molecular imaging methods. CONCLUSION: Taken together, we report a more efficient method for derivation of hESC-ECs that express appropriate patterns of endothelial genes, form functional vessels in vivo, and improve cardiac function. These studies suggest that hESC-ECs may provide a novel therapy for ischemic heart disease in the future

    Alteration of pulmonary immunity to Listeria monocytogenes by diesel exhaust particles (DEPs). II. Effects of DEPs on T-cell-mediated immune responses in rats.

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    Previously, we showed that diesel exhaust particles (DEPs) suppressed pulmonary clearance of Listeria monocytogenes (Listeria) and inhibited the phagocytosis of alveolar macrophages and their response to Listeria in the secretion of interleukin (IL)-1 beta, tumor necrosis factor alpha, and IL-12. In this report we examined the effects of DEPs and/or Listeria on T-cell development and secretion of IL-2, IL-6, and interferon (IFN)-gamma. We exposed Brown Norway rats to clean air or DEPs at 50 or 100 mg/m3 for 4 hr by nose-only inhalation and inoculated with 100,000 Listeria. Lymphocytes in the lung-draining lymph nodes were isolated at 3 and 7 days postexposure, analyzed for CD4+ and CD8+ cells, and measured for cytokine production in response to concanavalin A or heat-killed L. monocytogenes. Listeria infection induced lymphocyte production of IL-6. At 7 days postinfection, lymphocytes from Listeria-infected rats showed significant increases in CD4+ and CD8+ cell counts and the CD8+/CD4+ ratio and exhibited increased production of IFN-gamma and IL-2 receptor expression compared with the noninfected control. These results suggest an immune response that involves the action of IL-6 on T-cell activation, yielding Listeria-specific CD8+ cells. DEP exposure alone enhanced lymphocyte production of both IL-2 and IL-6 but inhibited lymphocyte secretion of IFN-gamma. In rats exposed to 100 mg/m3 DEPs and Listeria, a 10-fold increase occurred in pulmonary bacterial count at 3 days postinfection when compared with the Listeria-only exposure group. The isolated lymphocytes showed a significant increase in the CD4+ and CD8+ cell counts and the CD8+/CD4+ ratio and exhibited increased IL-2 responsiveness and increased capacity in the secretion of IL-2, IL-6, and IFN-gamma. This T-cell immune response was sufficient to allow the Brown Norway rats to clear the bacteria at 7 days postinfection and overcome the down-regulation of the innate immunity by the acute DEP exposure

    Reprogramming human T cell function and specificity with non-viral genome targeting.

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    Decades of work have aimed to genetically reprogram T cells for therapeutic purposes1,2 using recombinant viral vectors, which do not target transgenes to specific genomic sites3,4. The need for viral vectors has slowed down research and clinical use as their manufacturing and testing is lengthy and expensive. Genome editing brought the promise of specific and efficient insertion of large transgenes into target cells using homology-directed repair5,6. Here we developed a CRISPR-Cas9 genome-targeting system that does not require viral vectors, allowing rapid and efficient insertion of large DNA sequences (greater than one kilobase) at specific sites in the genomes of primary human T cells, while preserving cell viability and function. This permits individual or multiplexed modification of endogenous genes. First, we applied this strategy to correct a pathogenic IL2RA mutation in cells from patients with monogenic autoimmune disease, and demonstrate improved signalling function. Second, we replaced the endogenous T cell receptor (TCR) locus with a new TCR that redirected T cells to a cancer antigen. The resulting TCR-engineered T cells specifically recognized tumour antigens and mounted productive anti-tumour cell responses in vitro and in vivo. Together, these studies provide preclinical evidence that non-viral genome targeting can enable rapid and flexible experimental manipulation and therapeutic engineering of primary human immune cells

    Potential Cost-Effectiveness of Universal Access to Modern Contraceptives in Uganda

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    <div><h3>Background</h3><p>Over two thirds of women who need contraception in Uganda lack access to modern effective methods. This study was conducted to estimate the potential cost-effectiveness of achieving universal access to modern contraceptives in Uganda by implementing a hypothetical new contraceptive program (NCP) from both societal and governmental (Ministry of Health (MoH)) perspectives.</p> <h3>Methodology/Principal Findings</h3><p>A Markov model was developed to compare the NCP to the status quo or current contraceptive program (CCP). The model followed a hypothetical cohort of 15-year old girls over a lifetime horizon. Data were obtained from the Uganda National Demographic and Health Survey and from published and unpublished sources. Costs, life expectancy, disability-adjusted life expectancy, pregnancies, fertility and incremental cost-effectiveness measured as cost per life-year (LY) gained, cost per disability-adjusted life-year (DALY) averted, cost per pregnancy averted and cost per unit of fertility reduction were calculated. Univariate and probabilistic sensitivity analyses were performed to examine the robustness of results. Mean discounted life expectancy and disability-adjusted life expectancy (DALE) were higher under the NCP vs. CCP (28.74 vs. 28.65 years and 27.38 vs. 27.01 respectively). Mean pregnancies and live births per woman were lower under the NCP (9.51 vs. 7.90 and 6.92 vs. 5.79 respectively). Mean lifetime societal costs per woman were lower for the NCP from the societal perspective (1,949vs.1,949 vs. 1,987) and the MoH perspective (636vs.636 vs. 685). In the incremental analysis, the NCP dominated the CCP, i.e. it was both less costly and more effective. The results were robust to univariate and probabilistic sensitivity analysis.</p> <h3>Conclusion/Significance</h3><p>Universal access to modern contraceptives in Uganda appears to be highly cost-effective. Increasing contraceptive coverage should be considered among Uganda's public health priorities.</p> </div

    Evaluation of medical student self-rated preparedness to care for limited english proficiency patients

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    <p>Abstract</p> <p>Background</p> <p>Patients with limited English proficiency (LEP) represent a growing proportion of the US population and are at risk of receiving suboptimal care due to difficulty communicating with healthcare providers who do not speak their language. Medical school curricula are required to prepare students to care for all patients, including those with LEP, but little is known about how well they achieve this goal. We used data from a survey of medical students' cross-cultural preparedness, skills, and training to specifically explore their self-rated preparedness to care for LEP patients.</p> <p>Methods</p> <p>We electronically surveyed students at one northeastern US medical school. We used bivariate analyses to identify factors associated with student self-rated preparedness to care for LEP patients including gender, training year, first language, race/ethnicity, percent LEP and minority patients seen, and skill with interpreters. We used multivariate logistic regression to examine the independent effect of each factor on LEP preparedness. In a secondary analysis, we explored the association between year in medical school and self-perceived skill level in working with an interpreter.</p> <p>Results</p> <p>Of 651 students, 416 completed questionnaires (63.9% response rate). Twenty percent of medical students reported being very well or well-prepared to care for LEP patients. Of these, 40% were in their fourth year of training. Skill level working with interpreters, prevalence of LEP patients seen, and training year were correlated (p < 0.001) with LEP preparedness. Using multivariate logistic regression, only student race/ethnicity and self-rated skill with interpreters remained statistically significant. Students in third and fourth years were more likely to feel skilled with interpreters (p < 0.001).</p> <p>Conclusions</p> <p>Increasingly, medical students will need to be prepared to care for LEP patients. Our study supports two strategies to improve student preparedness: training students to work effectively with interpreters and increasing student diversity to better reflect the changing US demographics.</p
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