349 research outputs found

    ANÁLISE Numérica de Cisalhamento em Lajes Alveolares Protendidas

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    Este trabalho analisa numericamente o comportamento de lajes alveolares protendidas de uso corrente no Brasil quanto ao cisalhamento, para diferentes situações: sem capa estrutural, com variações na protensão e no posicionamento dos apoios. Buscando estudar, compreender e aperfeiçoar o uso destas peças, são realizadas modelagens por meio de uma análise numérica via elementos finitos utilizando o programa computacional ANSYS V.15 para reproduzir ensaios físicos já realizados e assim comparar os resultados numéricos aos experimentais a fim de calibrar o uso do programa para o estudo destas lajes. Os resultados obtidos são comparados com resultados teóricos obtidos por meio da utilização das formulações disponíveis nas normas ABNT NBR 14861:2011 e ABNT NBR 6118:2014. Logo, com esta pesquisa, foi possível mensurar o conservadorismo na norma brasileira vigente para o cálculo da resistência ao cisalhamento de lajes alveolares protendidas sem capa estrutural, ampliando o embasamento teórico e vislumbrando novos trabalhos acerca do assunto

    Efficacy of pulsatile flow perfusion in adult cardiac surgery: Hemodynamic energy and vascular reactivity

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    Background: The role of pulsatile (PP) versus non-pulsatile (NP) flow during a cardiopulmonary bypass (CPB) is still debated. This study’s aim was to analyze hemodynamic effects, endothelial reactivity and erythrocytes response during a CPB with PP or NP. Methods: Fifty-two patients undergoing an aortic valve replacement were prospectively randomized for surgery with either PP or NP flow. Pulsatility was evaluated in terms of energy equivalent pressure (EEP) and surplus hemodynamic energy (SHE). Systemic (SVRi) and pulmonary (PVRi) vascular resistances, endothelial markers levels and erythrocyte nitric-oxide synthase (eNOS) activity were collected at different perioperative time-points. Results: In the PP group, the resultant EEP was 7.3% higher than the mean arterial pressure (MAP), which corresponded to 5150 ± 2291 ergs/cm3 of SHE. In the NP group, the EEP and MAP were equal; no SHE was produced. The PP group showed lower SVRi during clamp-time (p = 0.06) and lower PVRi after protamine administration and during first postoperative hours (p = 0.02). Lower SVRi required a higher dosage of norepinephrine in the PP group (p = 0.02). Erythrocyte eNOS activity results were higher in the PP patients (p = 0.04). Renal function was better preserved in the PP group (p = 0.001), whereas other perioperative variables were comparable between the groups. Conclusions: A PP flow during a CPB results in significantly lower SVRi, PVRi and increased eNOS production. The clinical impact of increased perioperative vasopressor requirements in the PP group deserves further evaluation

    Randomized controlled trial comparing the effectiveness of 308-nm excimer laser alone or in combination with topical hydrocortisone 17-butyrate cream in the treatment of vitiligo of the face and neck.

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    Background Vitiligo is a pigmentary disorder which may have disfiguring consequences. Its treatment remains a challenge. Objectives We designed a parallel-group randomized controlled trial to compare the effectiveness of 308-nm excimer laser alone or in combination with topical hydrocortisone 17-butyrate cream in patients with vitiligo unresponsive to previous treatment with topical steroids or narrow-band ultraviolet (UV) B phototherapy. Methods Consecutive patients aged 18\u201375 years with nonsegmental vitiligo localized on the face and \u2044or neck lacking response to previous conventional treatment were eligible. In total, 84 patients (44 women and 40 men, mean age 44 years) were randomized to 308-nm excimer laser phototherapy twice weekly alone or in combination with topical hydrocortisone 17-butyrate cream twice daily for three periods of 3 weeks followed by a 1-week steroid-free interval. The primary outcome was a reduction of at least 75% of the overall lesional areas as judged by automatic image analysis on reflected UV photographs, conducted blind to treatment assignment, at 12 weeks compared with baseline. Secondary outcomes were clearance, and improvements on Physician\u2019s Global Assessment (PGA) and Skindex-29 scores. Results A total of 76 (90%) patients completed the study. In an intention-to-treat analysis, seven [16\uc66%; 95% confidence interval (CI) 5\uc63\u201327\uc68%] patients in the excimer monotherapy arm and 18 (42\uc68%; 95% CI 27\uc68\u201357\uc68%) in the combination arm showed \u2021 75% reduction of vitiligo lesions at 12 weeks (v2 test 6\uc689, P = 0\uc60087). Clearance was observed in two (4\uc67%; 95% CI 1\uc66\u201311\uc62%) and nine (21\uc64%; 95% CI 9\uc60\u201333\uc68%) patients, respectively (Fisher\u2019s exact test P = 0\uc604). A significant difference also emerged for PGA scores, while no difference was documented for Skindex-29. Conclusions Recalcitrant vitiligo of the face and neck may benefit from the combination of excimer laser phototherapy with topical hydrocortisone 17-butyrate cream

    Primary cutaneous plasmacytoma after rejection of a transplanted kidney: case report and review of the literature.

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    Immunosuppressed organ allograft recipients are at risk of developing lymphomas and lymphoproliferative disorders as a consequence of immunosuppressive therapy and long-term antigenic stimulation from both the graft and possible viral infections. No more than 4% of the malignant tumors detected in organ recipients are plasmacytomas. Primary cutaneous plasmacytoma is a rare type of cutaneous B-cell lymphoma arising primarily in the skin. It is derived from clonally expanded plasma cells with various degrees of maturation and atypia. We report the occurrence of a solitary cutaneous plasmacytoma in a 56-year-old male patient undergoing hemodialysis after rejection of a grafted kidney. The diagnosis was made a few months after the kidney had been surgically removed. A thorough examination showed no evidence of systemic disease. Skin lesions were successfully treated with local radiotherapy. After 2 years of follow-up there were no local or systemic recurrences

    Incidence and clinical predictors of a subsequent nonmelanoma skin cancer in solid organ transplant recipients with a first nonmelanoma skin cancer: a multicenter cohort study.

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    Objective: To compare the long-term risk of primary nonmelanoma skin cancer (NMSC) and the risk of subsequent NMSC in kidney and heart transplant recipients. Design: Partially retrospective cohort study. Setting: Two Italian transplantation centers. Patients: The study included 1934 patients: 1476 renal transplant recipients and 458 heart transplant recipients. Main Outcome Measures: Cumulative incidences and risk factors of the first and subsequent NMSCs. Results: Two hundred patients developed a first NMSC after a median follow-up of 6.8 years after transplantation. The 3-year risk of the primary NMSC was 2.1%. Of the 200 patients with a primary NMSC, 91 (45.5%) had a secondNMSCafter a median follow-up after the firstNMSC of 1.4 years (range, 3 months to 10 years). The 3-year risk of a second NMSC was 32.2%, and it was 49 times higher than that in patients with no previous NMSC. In a Cox proportional hazards regression model, age older than 50 years at the time of transplantation and male sex were significantly related to the first NMSC. Occurrence of the subsequent NMSC was not related to any risk factor considered, including sex, age at transplantation, type of transplanted organ, type of immunosuppressive therapy, histologic type of the first NMSC, and time since diagnosis of the first NMSC. Histologic type of the first NMSC strongly predicted the type of the subsequent NMSC. Conclusions: Development of a first NMSC confers a high risk of a subsequent NMSC in transplant recipients. Intensive long-term dermatologic follow-up of these patients is advisable

    Comparative efficacy and tolerability of medications for attention-deficit hyperactivity disorder in children, adolescents, and adults: a systematic review and network meta-analysis

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    Background: The benefits and safety of medications for attention-deficit hyperactivity disorder (ADHD) remain controversial, and guidelines are inconsistent on which medications are preferred across different age groups. We aimed to estimate the comparative efficacy and tolerability of oral medications for ADHD in children, adolescents, and adults. Methods: We did a literature search for published and unpublished double-blind randomised controlled trials comparing amphetamines (including lisdexamfetamine), atomoxetine, bupropion, clonidine, guanfacine, methylphenidate, and modafinil with each other or placebo. We systematically contacted study authors and drug manufacturers for additional information. Primary outcomes were efficacy (change in severity of ADHD core symptoms based on teachers' and clinicians' ratings) and tolerability (proportion of patients who dropped out of studies because of side-effects) at timepoints closest to 12 weeks, 26 weeks, and 52 weeks. We estimated summary odds ratios (ORs) and standardised mean differences (SMDs) using pairwise and network meta-analysis with random effects. We assessed the risk of bias of individual studies with the Cochrane risk of bias tool and confidence of estimates with the Grading of Recommendations Assessment, Development, and Evaluation approach for network meta-analyses. This study is registered with PROSPERO, number CRD42014008976. Findings: 133 double-blind randomised controlled trials (81 in children and adolescents, 51 in adults, and one in both) were included. The analysis of efficacy closest to 12 weeks was based on 10 068 children and adolescents and 8131 adults; the analysis of tolerability was based on 11 018 children and adolescents and 5362 adults. The confidence of estimates varied from high or moderate (for some comparisons) to low or very low (for most indirect comparisons). For ADHD core symptoms rated by clinicians in children and adolescents closest to 12 weeks, all included drugs were superior to placebo (eg, SMD −1·02, 95% CI −1·19 to −0·85 for amphetamines, −0·78, −0·93 to −0·62 for methylphenidate, −0·56, −0·66 to −0·45 for atomoxetine). By contrast, for available comparisons based on teachers' ratings, only methylphenidate (SMD −0·82, 95% CI −1·16 to −0·48) and modafinil (−0·76, −1·15 to −0·37) were more efficacious than placebo. In adults (clinicians' ratings), amphetamines (SMD −0·79, 95% CI −0·99 to −0·58), methylphenidate (−0·49, −0·64 to −0·35), bupropion (−0·46, −0·85 to −0·07), and atomoxetine (−0·45, −0·58 to −0·32), but not modafinil (0·16, −0·28 to 0·59), were better than placebo. With respect to tolerability, amphetamines were inferior to placebo in both children and adolescents (odds ratio [OR] 2·30, 95% CI 1·36–3·89) and adults (3·26, 1·54–6·92); guanfacine was inferior to placebo in children and adolescents only (2·64, 1·20–5·81); and atomoxetine (2·33, 1·28–4·25), methylphenidate (2·39, 1·40–4·08), and modafinil (4·01, 1·42–11·33) were less well tolerated than placebo in adults only. In head-to-head comparisons, only differences in efficacy (clinicians' ratings) were found, favouring amphetamines over modafinil, atomoxetine, and methylphenidate in both children and adolescents (SMDs −0·46 to −0·24) and adults (−0·94 to −0·29). We did not find sufficient data for the 26-week and 52-week timepoints. Interpretation: Our findings represent the most comprehensive available evidence base to inform patients, families, clinicians, guideline developers, and policymakers on the choice of ADHD medications across age groups. Taking into account both efficacy and safety, evidence from this meta-analysis supports methylphenidate in children and adolescents, and amphetamines in adults, as preferred first-choice medications for the short-term treatment of ADHD. New research should be funded urgently to assess long-term effects of these drugs. Funding: Stichting Eunethydis (European Network for Hyperkinetic Disorders), and the UK National Institute for Health Research Oxford Health Biomedical Research Centre

    Assessing Helicobacter pylori motility and biofilm formation in subinhibitory concentrations of antimicrobials.

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    Numerous studies have shown that subinhibitory concentrations of antimicrobials can alter bacterial virulence factors. This study evaluates motility and biofilm formation by H. pylori 43504 grown in subinhibitory concentrations of amoxicillin (AMX), clarithromycin (CLA), or tetracycline (TET). For the swimming and swarming motility assays, H. pylori 43504 suspensions were prepared with the strain alone or with the strain in AMX, CLA, or TET at ½ MIC. Next, the media were incubated at 37 ºC, under microaerophilia. To assess biofilm formation in the presence of one of the antimicrobials at subinhibitory antimicrobial concentrations, bacterial suspensions (109 CFU/mL) were prepared in 2.5% FBS containing AMX, CLA, or TET at ½ MIC. After incubation for 10 days, H. pylori 43504 grown in medium containing AMX, CLA, or TET at ½ MIC presented greater swimming motility and lower swarming motility than the non-treated strain. H. pylori 43504 grown in medium containing AMX, CLA, or TET at ½ MIC showed stronger biofilm production than the non-treated strain. Our results showed that AMX, CLA, or TET at subinhibitory concentrations favors H. pylori 43504 swimming motility and biofilm formation after incubation for 3 days. This may have clinical consequences and make the microorganism difficult to eradicate
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