348 research outputs found

    Loureirin B, an essential component of Sanguis Draxonis, inhibits Kv1.3 channel and suppresses cytokine release from Jurkat T cells

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    Sanguis draxonis (SD), also known as “Dragon’s Blood”, is a traditional herb medicine that has been used to treat a variety of complications with unknown mechanisms. Recent studies show that SD displays immunosuppressive activities and improves symptoms of type I diabetes in animal models. However, the mechanisms underlying SD’s immunosuppressive actions are not completely understood. The voltage-gated Kv1.3 channel plays a critical role in the pathogenesis of autoimmune diseases by regulating the functions of both T cells and B cells. Here we investigated the effect of SD and one of its active components loureirin B (LrB) on Kv1.3. Both SD and LrB inhibited Kv1.3-mediated currents, produced a membrane depolarization, and reduced Ca(2+) influx in Jurkat T cells. In addition, application of LrB inhibited phytohemagglutinin (PHA)-induced IL-2 release from activated Jurkat T cells. Furthermore, point mutations in the selective filter region significantly reduced the inhibitory effect of LrB on Kv1.3. The results of these experiments provide evidence that LrB is a channel blocker of Kv1.3 by interacting with amino acid residues in its selective filter region. Direct inhibition of Kv1.3 in T cells by SD and LrB might be the cellular and molecular basis of SD-mediated immunosuppression

    Histone Deacetylase Inhibitors Impair the Elimination of HIV-Infected Cells by Cytotoxic T-Lymphocytes

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    Resting memory CD4+ T-cells harboring latent HIV proviruses represent a critical barrier to viral eradication. Histone deacetylase inhibitors (HDACis), such as suberanilohydroxamic acid (SAHA), romidepsin, and panobinostat have been shown to induce HIV expression in these resting cells. Recently, it has been demonstrated that the low levels of viral gene expression induced by a candidate HDACi may be insufficient to cause the death of infected cells by viral cytopathic effects, necessitating their elimination by immune effectors, such as cytotoxic T-lymphocytes (CTL). Here, we study the impact of three HDACis in clinical development on T-cell effector functions. We report two modes of HDACi-induced functional impairment: i) the rapid suppression of cytokine production from viable T-cells induced by all three HDACis ii) the selective death of activated T-cells occurring at later time-points following transient exposures to romidepsin or, to a lesser extent, panobinostat. As a net result of these factors, HDACis impaired CTL-mediated IFN-γ production, as well as the elimination of HIV-infected or peptide-pulsed target cells, both in liquid culture and in collagen matrices. Romidepsin exerted greater inhibition of antiviral function than SAHA or panobinostat over the dose ranges tested. These data suggest that treatment with HDACis to mobilize the latent reservoir could have unintended negative impacts on the effector functions of CTL. This could influence the effectiveness of HDACi-based eradication strategies, by impairing elimination of infected cells, and is a critical consideration for trials where therapeutic interruptions are being contemplated, given the importance of CTL in containing rebound viremia

    Whisker Movements Reveal Spatial Attention: A Unified Computational Model of Active Sensing Control in the Rat

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    Spatial attention is most often investigated in the visual modality through measurement of eye movements, with primates, including humans, a widely-studied model. Its study in laboratory rodents, such as mice and rats, requires different techniques, owing to the lack of a visual fovea and the particular ethological relevance of orienting movements of the snout and the whiskers in these animals. In recent years, several reliable relationships have been observed between environmental and behavioural variables and movements of the whiskers, but the function of these responses, as well as how they integrate, remains unclear. Here, we propose a unifying abstract model of whisker movement control that has as its key variable the region of space that is the animal's current focus of attention, and demonstrate, using computer-simulated behavioral experiments, that the model is consistent with a broad range of experimental observations. A core hypothesis is that the rat explicitly decodes the location in space of whisker contacts and that this representation is used to regulate whisker drive signals. This proposition stands in contrast to earlier proposals that the modulation of whisker movement during exploration is mediated primarily by reflex loops. We go on to argue that the superior colliculus is a candidate neural substrate for the siting of a head-centred map guiding whisker movement, in analogy to current models of visual attention. The proposed model has the potential to offer a more complete understanding of whisker control as well as to highlight the potential of the rodent and its whiskers as a tool for the study of mammalian attention

    Surgical site infection after gastrointestinal surgery in high-income, middle-income, and low-income countries: a prospective, international, multicentre cohort study

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    Background: Surgical site infection (SSI) is one of the most common infections associated with health care, but its importance as a global health priority is not fully understood. We quantified the burden of SSI after gastrointestinal surgery in countries in all parts of the world. Methods: This international, prospective, multicentre cohort study included consecutive patients undergoing elective or emergency gastrointestinal resection within 2-week time periods at any health-care facility in any country. Countries with participating centres were stratified into high-income, middle-income, and low-income groups according to the UN's Human Development Index (HDI). Data variables from the GlobalSurg 1 study and other studies that have been found to affect the likelihood of SSI were entered into risk adjustment models. The primary outcome measure was the 30-day SSI incidence (defined by US Centers for Disease Control and Prevention criteria for superficial and deep incisional SSI). Relationships with explanatory variables were examined using Bayesian multilevel logistic regression models. This trial is registered with ClinicalTrials.gov, number NCT02662231. Findings: Between Jan 4, 2016, and July 31, 2016, 13 265 records were submitted for analysis. 12 539 patients from 343 hospitals in 66 countries were included. 7339 (58·5%) patient were from high-HDI countries (193 hospitals in 30 countries), 3918 (31·2%) patients were from middle-HDI countries (82 hospitals in 18 countries), and 1282 (10·2%) patients were from low-HDI countries (68 hospitals in 18 countries). In total, 1538 (12·3%) patients had SSI within 30 days of surgery. The incidence of SSI varied between countries with high (691 [9·4%] of 7339 patients), middle (549 [14·0%] of 3918 patients), and low (298 [23·2%] of 1282) HDI (p < 0·001). The highest SSI incidence in each HDI group was after dirty surgery (102 [17·8%] of 574 patients in high-HDI countries; 74 [31·4%] of 236 patients in middle-HDI countries; 72 [39·8%] of 181 patients in low-HDI countries). Following risk factor adjustment, patients in low-HDI countries were at greatest risk of SSI (adjusted odds ratio 1·60, 95% credible interval 1·05–2·37; p=0·030). 132 (21·6%) of 610 patients with an SSI and a microbiology culture result had an infection that was resistant to the prophylactic antibiotic used. Resistant infections were detected in 49 (16·6%) of 295 patients in high-HDI countries, in 37 (19·8%) of 187 patients in middle-HDI countries, and in 46 (35·9%) of 128 patients in low-HDI countries (p < 0·001). Interpretation: Countries with a low HDI carry a disproportionately greater burden of SSI than countries with a middle or high HDI and might have higher rates of antibiotic resistance. In view of WHO recommendations on SSI prevention that highlight the absence of high-quality interventional research, urgent, pragmatic, randomised trials based in LMICs are needed to assess measures aiming to reduce this preventable complication

    Оценка качества образования на основе компетентностного подхода

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    В работе представлен практический опыт оценки качества образования в новом формате компетентностного подход

    Strategies to reduce clinical inertia in hypertensive kidney transplant recipients

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    <p>Abstract</p> <p>Background</p> <p>Many kidney transplant recipients have hypertension. Elevated systolic blood pressures are associated with lower patient and kidney allograft survival.</p> <p>Methods</p> <p>This retrospective analysis examined the prevalence of clinical inertia (failure to initiate or increase therapy) in the treatment of hypertension before and after the introduction of an automated device (BpTRU) in the kidney transplant clinic.</p> <p>Results</p> <p>Historically only 36% (49/134) of patients were prescribed a change in therapy despite a systolic blood pressure ≥ 130 mmHg. After the introduction of BpTRU, 56% (62/110) of the patients had a change in therapy. In a multivariate logistic regression analysis of the entire cohort (n = 244) therapeutic changes were associated with higher blood pressures (OR 1.08 per mmHg, 95% CI 1.04–1.12) and use of the BpTRU (OR 2.12, 95% CI 1.72–3.83). In addition patients on more medications were also more likely to have a change in therapy.</p> <p>Conclusion</p> <p>Blood pressure measurement with automated devices may help reduce clinical inertia in the kidney transplant clinic.</p

    Multiple volcanic episodes of flood basalts caused by thermochemical mantle plumes

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    The hypothesis that a single mushroom-like mantle plume head can generate a large igneous province within a few million years has been widely accepted(1). The Siberian Traps at the Permian Triassic boundary(2) and the Deccan Traps at the Cretaceous Tertiary boundary(3) were probably erupted within one million years. These large eruptions have been linked to mass extinctions. But recent geochronological data(4-11) reveal more than one pulse of major eruptions with diverse magma flux within several flood basalts extending over tens of million years. This observation indicates that the processes leading to large igneous provinces are more complicated than the purely thermal, single-stage plume model suggests. Here we present numerical experiments to demonstrate that the entrainment of a dense eclogite-derived material at the base of the mantle by thermal plumes can develop secondary instabilities due to the interaction between thermal and compositional buoyancy forces. The characteristic timescales of the development of the secondary instabilities and the variation of the plume strength are compatible with the observations. Such a process may contribute to multiple episodes of large igneous provinces.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/62705/1/nature03697.pd

    Consumption of single cigarettes and quitting behavior: A longitudinal analysis of Mexican smokers

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    <p>Abstract</p> <p>Background</p> <p>Previous cross-sectional research has suggested single cigarettes could either promote or inhibit consumption. The present study aimed to assess the effects of single cigarette availability and consumption on downstream quit behavior.</p> <p>Methods</p> <p>We analyzed population-based, longitudinal data from adult smokers who participated in the 2008 and 2010 administrations of the International Tobacco Control Policy Evaluation Survey in Mexico.</p> <p>Results</p> <p>At baseline, 30% of smokers saw single cigarettes for sale on a daily basis, 17% bought singles at their last purchase, and 7% bought singles daily. Smokers who most frequently purchased singles, both in general and specifically to control their consumption, were no more likely to attempt to quit over the 14 month follow-up period than those who did not purchase singles. Frequency of buying singles to reduce consumption had a non-monotonic association with being quit at followup. The odds of being quit was only statistically significant when comparing those who had not bought singles to reduce consumption with those who had done so on a more irregular basis (AOR = 2.30; 95% CI 1.19, 4.45), whereas those who did so more regularly were no more likely to be quit at followup. Frequency of self-reported urges to smoke upon seeing singles for sale was unassociated with either quit attempts or being quit at followup.</p> <p>Conclusions</p> <p>These results suggest that the relationship between singles consumption and quit behavior is complex, with no clear evidence that singles either promote or inhibit downstream quit behavior.</p

    Body mass index and annual increase of body mass index in long-term childhood cancer survivors; relationship to treatment

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    Evaluation of body mass index (BMI) at final height (FH) and annual BMI increase in adult childhood cancer survivors (CCS) after treatment with anthracyclines, platinum, and/or radiotherapy. BMI (weight/heightA(2)) was calculated retrospectively from diagnosis until FH. The prevalence of underweight (BMI < 18.5 kg/m(2)) and overweight (BMI a parts per thousand yenaEuro parts per thousand 25 kg/m(2))/obesity (BMI a parts per thousand yenaEuro parts per thousand 30 kg/m(2)) at FH was compared with age-matched controls. The association between underweight/overweight at FH and treatment was assessed by multivariate logistic regression. Annual BMI increase after treatment was assessed by multilevel analysis. Analyses were adjusted for age and underweight/overweight at diagnosis, and age at FH. At FH the prevalence of overweight had not increased, while CCS experienced more underweight as compared to controls (14% vs. 4%, P < 0.001). Overweight at FH was associated with cranial/craniospinal radiotherapy (CRT; OR, 2.23; 95% CI, 1.17-4.26) and underweight at FH with anthracyclines > 300 mg/m(2) (OR, 2.84; 95% CI, 1.33-6.06). Annual BMI increase was +0.47 (0.34-0.60) kg/m(2)/year. In CCS, the annual BMI increase was greater in those with CRT a parts per thousand yenaEuro parts per thousand 30 Gy as compared with those with less or no CRT (+0.15 kg/m(2)/year [0.04-0.25 kg/m(2)/year], P = 0.008) and smaller in those with a higher cumulative anthracycline dose (-0.03 kg/m(2)/year [-0.05 to -0.0005 kg/m(2)/year] per 100 mg/m(2), P = 0.046). After treatment with anthracyclines, platinum, and/or radiotherapy, CRT-treated survivors have more overweight at FH, and a greater annual BMI increase, while anthracycline-treated survivors have more underweight at FH and a lower annual BMI increase
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