201 research outputs found

    Micro-spectroscopic investigation of selenium-bearing minerals from the Western US Phosphate Resource Area

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    Mining activities in the US Western Phosphate Resource Area (WPRA) have released Se into the environment. Selenium has several different oxidation states and species, each having varying degrees of solubility, reactivity, and bioavailability. In this study we are investigating the speciation of Se in mine-waste rocks. Selenium speciation was determined using bulk and micro-x-ray absorption spectroscopy (XAS), as well as micro-x-ray fluorescence mapping. Rocks used for bulk-XAS were ground into fine powders. Shale used for micro-XAS was broken along depositional planes to expose unweathered surfaces. The near edge region of the XAS spectra (XANES) for the bulk rock samples revealed multiple oxidation states, with peaks indicative of Se(-II), Se(IV), and Se(+VI) species. Micro-XANES analysis of the shale indicated that three unique Se-bearing species were present. Using the XANES data together with ab initio fitting of the extended x-ray absorption fine structure region of the micro-XAS data (micro-EXAFS) the three Se-bearing species were identified as dzharkenite, a di-selenide carbon compound, and Se-substituted pyrite. Results from this research will allow for a better understanding of the biogeochemical cycling of Se in the WPRA

    Review for the generalist: evaluation of pediatric hip pain

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    Hip pathology may cause groin pain, referred thigh or knee pain, refusal to bear weight or altered gait in the absence of pain. A young child with an irritable hip poses a diagnostic challenge. Transient synovitis, one of the most common causes of hip pain in children, must be differentiated from septic arthritis. Hip pain may be caused by conditions unique to the growing pediatric skeleton including Perthes disease, slipped capital femoral epiphysis and apophyseal avulsion fractures of the pelvis. Hip pain may also be referred from low back or pelvic pathology. Evaluation and management requires a thorough history and physical exam, and understanding of the pediatric skeleton. This article will review common causes of hip and pelvic musculoskeletal pain in the pediatric population

    Contributions of the MyD88-Dependent Receptors IL-18R, IL-1R, and TLR9 to Host Defenses following Pulmonary Challenge with Cryptococcus neoformans

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    Signaling via the adapter protein, MyD88, is important in the host defense against Cryptococcus neoformans infection. While certain Toll-like receptors (TLRs) can enhance the clearance of Cryptococcus, the contributions of MyD88-dependent, TLR-independent pathways have not been fully investigated. We examined the roles of IL-1R and IL-18R in vivo by challenging C57BL/6 mice with a lethal strain of Cryptococcus. We found that the absence of IL-18R, but not IL-1R, causes a shift in the survival curve following pulmonary delivery of a virulent strain of C. neoformans (H99). Specifically, IL-18R-deficient mice have significantly shorter median survival times compared to wild-type mice following infection. Cytokine analysis of lung homogenates revealed that deficiency of IL-IR, IL-18R, or MyD88 is associated with diminished lung levels of IL-1β. In order to compare these findings with those related to TLR-deficiency, we studied the effects of TLR9-deficiency and found that deficiency of TLR9 also affects the survival curve of mice following challenge with C. neoformans. Yet the lungs from infected TLR9-deficient mice have robust levels of IL-1β. In summary, we found that multiple signaling components can contribute the MyD88-dependent host responses to cryptococcal infection in vivo and each drives distinct pulmonary responses

    Crisis discharges and readmission risk in acute psychiatric male inpatients

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    <p>Abstract</p> <p>Background</p> <p>Severe pressures on beds in psychiatric services have led to the implementation of an early ("crisis") discharge policy in the Western Cape, South Africa. The study examined the effect of this policy and length of hospital stay (LOS) on readmission rates in one psychiatric hospital in South Africa.</p> <p>Methods</p> <p>Discharge summaries of adult male patients (<it>n </it>= 438) admitted to Stikland Psychiatric Hospital during 2004 were retrospectively examined. Each patient's clinical course was then analysed for the period between January 1<sup>st</sup>, 2004, and August 31<sup>st</sup>, 2006.</p> <p>Results</p> <p>Although shorter LOS was associated with decreased readmission rates, the effect of crisis discharges was far more powerful. Patients discharged as usual had a far lower risk of readmission than those discharged due to bed pressures (i.e. crisis discharge).</p> <p>Conclusion</p> <p>Increased risks associated with the early discharge policy necessitate the urgent review of the current management of bed shortages in this inpatient facility. The strengthening of community initiatives, particularly assertive outreach could be a way forward.</p

    Postpartum behaviour as predictor of weight change from before pregnancy to one year postpartum

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    <p>Abstract</p> <p>Background</p> <p>Postpartum weight retention affects many women and increases the risk of becoming overweight. The research objective was to study modifiable factors contributing to weight change at one year postpartum.</p> <p>Methods</p> <p>In this prospective cohort, postpartum behavior, such as physical activity, sedentary behavior, sleep, and intake of total energy, total fat and saturated fatty acids of 118 Dutch women were assessed in 2003/2004 by self-report at 6 weeks, 6 and 12 months postpartum. Mean postpartum scores were computed for the behavioral measures. In linear regression models it was determined which factors were associated with average weight change from before pregnancy to one year postpartum. Furthermore, factors associated with substantial postpartum weight retention (≥ 5 kg) were also studied in logistic regression models.</p> <p>Results</p> <p>At one year postpartum, the average weight of participants had increased by 0.9 kg (SD 4.4). Moreover, 20% of the women retained ≥ 5 kg. Women who perceived themselves more physically active than others were almost ten times less likely to retain ≥ 5 kg than women who perceived themselves equally active (OR = 0.11, 95%CI: 0.02 - 0.66). Exceeding the guideline for saturated fatty acid intake (OR = 3.40, 95%CI: 1.04 - 11.11), total gestational weight gain (OR = 1.14/kg, 95%CI: 1.01 - 1.27), and not having completed post high school education (OR = 5.13, 95%CI: 1.66 - 15.90) increased the odds of retaining ≥ 5 kg.</p> <p>Conclusions</p> <p>Since one in five women had substantial weight retention postpartum, effective interventions for the prevention of weight retention are much needed. Future studies should evaluate whether interventions focusing on the identified modifiable postpartum factors are successful in reducing weight retention after childbirth.</p

    Murine Dendritic Cells Transcriptional Modulation upon Paracoccidioides brasiliensis Infection

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    Limited information is available regarding the modulation of genes involved in the innate host response to Paracoccidioides brasiliensis, the etiologic agent of paracoccidioidomycosis. Therefore, we sought to characterize, for the first time, the transcriptional profile of murine bone marrow-derived dendritic cells (DCs) at an early stage following their initial interaction with P. brasiliensis. DCs connect innate and adaptive immunity by recognizing invading pathogens and determining the type of effector T-cell that mediates an immune response. Gene expression profiles were analyzed using microarray and validated using real-time RT-PCR and protein secretion studies. A total of 299 genes were differentially expressed, many of which are involved in immunity, signal transduction, transcription and apoptosis. Genes encoding the cytokines IL-12 and TNF-α, along with the chemokines CCL22, CCL27 and CXCL10, were up-regulated, suggesting that P. brasiliensis induces a potent proinflammatory response in DCs. In contrast, pattern recognition receptor (PRR)-encoding genes, particularly those related to Toll-like receptors, were down-regulated or unchanged. This result prompted us to evaluate the expression profiles of dectin-1 and mannose receptor, two other important fungal PRRs that were not included in the microarray target cDNA sequences. Unlike the mannose receptor, the dectin-1 receptor gene was significantly induced, suggesting that this β-glucan receptor participates in the recognition of P. brasiliensis. We also used a receptor inhibition assay to evaluate the roles of these receptors in coordinating the expression of several immune-related genes in DCs upon fungal exposure. Altogether, our results provide an initial characterization of early host responses to P. brasiliensis and a basis for better understanding the infectious process of this important neglected pathogen

    MALDI imaging mass spectrometry for direct tissue analysis: a new frontier for molecular histology

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    Matrix-assisted laser desorption/ionization (MALDI) imaging mass spectrometry (IMS) is a powerful tool for investigating the distribution of proteins and small molecules within biological systems through the in situ analysis of tissue sections. MALDI-IMS can determine the distribution of hundreds of unknown compounds in a single measurement and enables the acquisition of cellular expression profiles while maintaining the cellular and molecular integrity. In recent years, a great many advances in the practice of imaging mass spectrometry have taken place, making the technique more sensitive, robust, and ultimately useful. In this review, we focus on the current state of the art of MALDI-IMS, describe basic technological developments for MALDI-IMS of animal and human tissues, and discuss some recent applications in basic research and in clinical settings

    Synaptic AMPA receptor composition in development, plasticity and disease

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