920 research outputs found
Structural analysis of the starfish SALMFamide neuropeptides S1 and S2: The N-terminal region of S2 facilitates self-association
The neuropeptides S1 (GFNSALMFamide) and S2 (SGPYSFNSGLTFamide), which share sequence similarity, were discovered in the starfish Asterias rubens and are prototypical members of the SALMFamide family of neuropeptides in echinoderms. SALMFamide neuropeptides act as muscle relaxants and both S1 and S2 cause relaxation of cardiac stomach and tube foot preparations in vitro but S2 is an order of magnitude more potent than S1. Here we investigated a structural basis for this difference in potency using spectroscopic techniques. Circular dichroism spectroscopy showed that S1 does not have a defined structure in aqueous solution and this was supported by 2D nuclear magnetic resonance experiments. In contrast, we found that S2 has a well-defined conformation in aqueous solution. However, the conformation of S2 was concentration dependent, with increasing concentration inducing a transition from an unstructured to a structured conformation. Interestingly, this property of S2 was not observed in an N-terminally truncated analogue of S2 (short S2 or SS2; SFNSGLTFamide). Collectively, the data obtained indicate that the N-terminal region of S2 facilitates peptide self-association at high concentrations, which may have relevance to the biosynthesis and/or bioactivity of S2 in vivo
Improving mental health and social participation outcomes in older adults with depression and anxiety: Study protocol for a randomised controlled trial
Background Increasing both the frequency and quality of social interactions within treatments for anxiety and depressive disorders in older adults may improve their mental health outcomes and quality of life. This study aims to evaluate the clinical efficacy and cost utility of an enhanced cognitive behavioural therapy (CBT) plus social participation program in a sample of older adults with depression and/or anxiety. Methods A total of 172 community-dwelling adults aged 65 years or older with an anxiety and/or depressive disorder will be randomly allocated to either an enhanced CBT plus social participation program (n = 86) or standard CBT (n = 86). Both treatments will be delivered during 12 weekly individual sessions utilising structured manuals and workbooks. Participants will be assessed at pre-treatment, post-treatment, and 12-month follow-up. The primary outcome evaluates mean change in clinician-rated diagnostic severity of anxiety and depressive disorders from baseline to post-treatment (primary endpoint) based on a semi-structured diagnostic interview. Secondary outcomes evaluate changes in symptomatology on self-report anxiety and depression measures, as well as changes in social/community participation, social network, and perceived social support, loneliness, quality of life, and use of health services. Economic benefits will be evaluated using a cost-utility analysis to derive the incremental cost utility ratios for the enhanced CBT program. Discussion Outcomes from this study will provide support for the establishment of improved psychosocial treatment for older adults with anxiety and/or depression. Study outcomes will also provide health systems with a clear means to reduce the impact of poor emotional health in older age and its associated economic burden. In addition to the empirical validation of a novel treatment, the current study will contribute to the current understanding of the role of social participation in older adult wellbeing
Synthesis and structural characterization of a mimetic membrane-anchored prion protein
During pathogenesis of transmissible spongiform encephalopathies (TSEs) an abnormal form (PrPSc) of the host encoded prion protein (PrPC) accumulates in insoluble fibrils and plaques. The two forms of PrP appear to have identical covalent structures, but differ in secondary and tertiary structure. Both PrPC and PrPSc have glycosylphospatidylinositol (GPI) anchors through which the protein is tethered to cell membranes. Membrane attachment has been suggested to play a role in the conversion of PrPC to PrPSc, but the majority of in vitro studies of the function, structure, folding and stability of PrP use recombinant protein lacking the GPI anchor. In order to study the effects of membranes on the structure of PrP, we synthesized a GPI anchor mimetic (GPIm), which we have covalently coupled to a genetically engineered cysteine residue at the C-terminus of recombinant PrP. The lipid anchor places the protein at the same distance from the membrane as does the naturally occurring GPI anchor. We demonstrate that PrP coupled to GPIm (PrP-GPIm) inserts into model lipid membranes and that structural information can be obtained from this membrane-anchored PrP. We show that the structure of PrP-GPIm reconstituted in phosphatidylcholine and raft membranes resembles that of PrP, without a GPI anchor, in solution. The results provide experimental evidence in support of previous suggestions that NMR structures of soluble, anchor-free forms of PrP represent the structure of cellular, membrane-anchored PrP. The availability of a lipid-anchored construct of PrP provides a unique model to investigate the effects of different lipid environments on the structure and conversion mechanisms of PrP
T helper cell subsets specific for pseudomonas aeruginosa in healthy individuals and patients with cystic fibrosis
Background: We set out to determine the magnitude of antigen-specific memory T helper cell responses to Pseudomonas aeruginosa in healthy humans and patients with cystic fibrosis.
Methods: Peripheral blood human memory CD4+ T cells were co-cultured with dendritic cells that had been infected with different strains of Pseudomonas aeruginosa. The T helper response was determined by measuring proliferation, immunoassay of cytokine output, and immunostaining of intracellular cytokines.
Results: Healthy individuals and patients with cystic fibrosis had robust antigen-specific memory CD4+ T cell responses to Pseudomonas aeruginosa that not only contained a Th1 and Th17 component but also Th22 cells. In contrast to previous descriptions of human Th22 cells, these Pseudomonal-specific Th22 cells lacked the skin homing markers CCR4 or CCR10, although were CCR6+. Healthy individuals and patients with cystic fibrosis had similar levels of Th22 cells, but the patient group had significantly fewer Th17 cells in peripheral blood.
Conclusions: Th22 cells specific to Pseudomonas aeruginosa are induced in both healthy individuals and patients with cystic fibrosis. Along with Th17 cells, they may play an important role in the pulmonary response to this microbe in patients with cystic fibrosis and other conditions
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Analysis of warm prestress data
Loading a cracked structure at elevated temperature, or warm prestressing (WPS), enhances its fracture resistance at a lower temperature. Five data sets, comprising 119 unclad pressure vessel steel specimens, were combined to derive correlations for WPS-enhanced fracture toughness (K{sub Ifrac}) in the absence of ductile tearing. New WPS test results for 27 surface flawed specimens, eight subclad flawed specimens, and five strain-aged specimens are discussed. K{sub Ifrac} exceeded non-WPS fracture toughness, K{sub Ic}, for all experiments. The WPS data showed that no specimens failed while K was decreasing, and that at least an additional seven percent additional reloading from the minimum value of applied K{sub I} took place prior to final fracture. The data included complete and partial unloading after WPS prior to final fracture. Crack tip 3-dimensional elastic-plastic finite element (3DEPFE) analysis was performed to support statistical analysis of the data. Regression models were compared with the Chell WPS model. Crack tip 3DEPFE analysis indicated that partially unloaded and completely unloaded data should be treated separately, and that the amount of unloading is unimportant for partially unloaded data. The regression models, which use K{sub I} at WPS (K{sub Iwps}) and K{sub Ic} as independent variables, better represented the WPS benefit than did the more complicated Chell model. An adequate accounting was made for constraint in the WPS experiments. The subclad flaw data support the use of the partial unload regression model, provided that some care is taken to represent the effect of intact cladding if present. The effect of strain aging at or below 260 C (500 F) on WPS benefit was of no consequence for the pressure vessel steels and WPS temperatures used to derive the regression models. The presence of ductile tearing precludes the use of the regression models. The regression model for partial unloading accurately predicted the behavior of full scale pressure vessel WPS experiments. All but one of the 174 experiments considered lie above the lower 2{sigma} estimate of the regressions. The experiments all supported Type I WPS, i.e., there was no fracture during cooling until reloading occurred. However, the regression equations apply to the reload, and are inapplicable to Type I WPS
Additive manufacturing of inorganic scintillator-based particle detectors
Inorganic scintillators are widely used for scientific, industrial and
medical applications. The development of 3D printing with inorganic
scintillators would allow fast creation of detector prototypes for registration
of ionizing radiation, such as alpha and beta, gamma particles in thin layers
of active material and soft X-ray radiation. This article reports on the
technical work and scientific achievements that aimed at developing a new
inorganic scintillation filament to be used for the 3D printing of composite
scintillator materials: study and definition of the scintillator composition;
development of the methods for the inorganic scintillator filament production
and further implementation in the available 3D printing technologies; study of
impact of the different 3D printing modes on the material scintillation
characteristics. Also, 3D printed scintillators can be used for creation of
combined detectors for high-energy physics.Comment: 14 pages, 16 figure
A randomized study evaluating cinacalcet to treat hypercalcemia in renal transplant recipients with persistent hyperparathyroidism
Persistent hyperparathyroidism (HPT) after kidney transplantation (KTx) is associated with hypercalcemia, hypophosphatemia and abnormally high levels of parathyroid hormone (PTH). In this randomized trial, cinacalcet was compared to placebo for the treatment of hypercalcemia in adult patients with persistent HPT after KTx. Subjects were randomized 1:1 to cinacalcet or placebo with randomization stratified by baseline corrected total serum calcium levels ( 6411.2 mg/dL [2.80 mmol/L] or >11.2 mg/dL [2.80 mmol/L]). The primary end point was achievement of a mean corrected total serum calcium value <10.2 mg/dL (2.55 mmol/L) during the efficacy period. The two key secondary end points were percent change in bone mineral density (BMD) at the femoral neck and absolute change in phosphorus; 78.9% cinacalcet- versus 3.5% placebo-treated subjects achieved the primary end point with a difference of 75.4% (95% confidence interval [CI]: 63.8, 87.1), p < 0.001. There was no statistical difference in the percent change in BMD at the femoral neck between cinacalcet and placebo groups, p = 0.266. The difference in the change in phosphorus between the two arms was 0.45 mg/dL (95% CI: 0.26, 0.64), p < 0.001 (nominal). No new safety signals were detected. In conclusion, hypercalcemia and hypophosphatemia were effectively corrected after treatment with cinacalcet in patients with persistent HPT after KTx. This randomized, placebo-controlled trial demonstrates that cinacalcet effectively and safely corrects hypercalcemia in adult patients with persistent hyperparathyroidism after successful kidney transplantation. See editorial by Coyne and Delos Santos on page 2446
Fungal vaccines and immunotherapeutics: current concepts and future challenges
Purpose of review The remarkable advances in modern medicine have paradoxically resulted in a rapidly expanding population of immunocompromised patients displaying extreme susceptibility to life-threatening fungal infections. There are currently no licensed vaccines, and the prophylaxis and therapy of fungal infections in at-risk individuals remains challenging, contributing to undesirable mortality and morbidity rates. The design of successful antifungal preventive approaches has been hampered by an insufficient understanding of the dynamics of the host-fungus interaction and the mechanisms that underlie heterogenous immune responses to vaccines and immunotherapy. Recent findings Recent advances in proteomics and glycomics have contributed to the identification of candidate antigens for use in subunit vaccines, novel adjuvants, and delivery systems to boost the efficacy of protective vaccination responses that are becoming available, and several targets are being exploited in immunotherapeutic approaches. Summary We review some of the emerging concepts as well as the inherent challenges to the development of fungal vaccines and immunotherapies to protect at-risk individuals.ThisworkwassupportedbytheNorthernPortugal Regional Operational Programme (NORTE 2020), under the Portugal 2020 Partnership Agreement, through the European Regional Development Fund (FEDER) (NORTE-01-0145-FEDER-000013), and the Fundação para a Ciência e Tecnologia (FCT) (contracts IF/00735/ 2014 to A.C., and SFRH/BPD/96176/2013 to C.C).info:eu-repo/semantics/publishedVersio
The Role of TSLP in IL-13-Induced Atopic March
Although atopic dermatitis (AD) is the initial step of the “atopic march”, a progression from AD to asthma, the underlying mechanism remains unknown. Selective expression of IL-13 in the skin of mice caused an AD phenotype resembling human AD, and the disorder was associated with enhanced production of thymic stromal lymphopoietin (TSLP) in the AD skin with a systemic Th2 immunity. Here we show that IL-13 transgenic mice with AD had significantly enhanced lung inflammation, mucus hypersecretion, and airway hyperresponsiveness (AHR) when sensitized and challenged by allergen. In addition, the level of TSLP was significantly higher in acute AD than in chronic AD. Furthermore, elimination of TSLP signaling significantly diminished the allergic asthma responses, immune cell production of Th2 cytokines (IL-4, IL-13), and serum IgE. These studies indicate that IL-13 induces AD and atopic march via a TSLP dependent mechanism
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