270 research outputs found

    Validation of a hemodynamic model for the study of the cerebral venous outflow system using MR imaging and echo- Color doppler data

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    BACKGROUND AND PURPOSE: A comprehensive parameter model was developed to investigate correlations between cerebral hemodynamics and alterations in the extracranial venous circulation due to posture changes and/or extracranial venous obstruction (stenosis). The purpose of this work was to validate the simulation results by using MR imaging and echo-color Doppler experimental blood flow data in humans. MATERIALS AND METHODS: To validate the model outcomes, we used supine average arterial and venous extracerebral blood flow, obtained by using phase-contrast MR imaging from 49 individuals with stenosis in the acquisition plane at the level of the disc between the second and third vertebrae of the left internal jugular vein, 20 with stenosis in the acquisition plane at the level of the disc between the fifth and sixth vertebrae of the right internal jugular vein, and 38 healthy controls without stenosis. Average data from a second group of 10 healthy volunteers screened with an echo-color Doppler technique were used to evaluate flow variations due to posture change. RESULTS: There was excellent agreement between experimental and simulated supine flows. Every simulated CBF fell inside the standard error from the corresponding average experimental value, as well as most of the simulated extracerebral arterial flow (extracranial blood flow from the head and face, measured at the level of the disc between second and third vertebrae) and venous flows. Simulations of average jugular and vertebral blood flow variations due to a change of posture from supine to upright also matched the experimental data. CONCLUSIONS: The good agreement between simulated and experimental results means that the model can correctly reproduce the main factors affecting the extracranial circulation and could be used to study other types of stenotic conditions not represented by the experimental data

    Robotics in uro-oncologic surgery

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    In urology, the main use for the robotic technique has been in radical prostatectomy for prostate cancer. Robotic surgery for other organs, such as the kidneys and bladder, has been less explored. However, partial nephrectomy or radical nephroureterectomy can be difficult for inexperienced laparoscopic surgeons. The advent of the da Vinci robot, with multijointed endowristed instruments and stereoscopic vision, decreases the technical difficulty of intracorporeal suturing and improves the reconstructive steps. The objective of this article is to offer an overview of all robotic procedures recently developed in the field of urology. We evaluate the feasibility of these procedures and their potential advantages and disadvantages. We also describe perioperative, postoperative, and oncologic outcomes of robot-assisted surgery as well as perform a comparison with open and laparoscopic techniques. Comparative data and an adequate follow-up are needed to demonstrate equivalent oncologic outcomes in comparison with traditional open or laparoscopic procedures. Copyright

    Cloning of nitroalkane oxidase from Fusarium oxysporum identifies a new member of the acyl-CoA dehydrogenase superfamily

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    The flavoprotein nitroalkane oxidase (NAO) from Fusarium oxysporum catalyzes the oxidation of nitroalkanes to the respective aldehydes with production of nitrite and hydrogen peroxide. The sequences of several peptides from the fungal enzyme were used to design oligonucleotides for the isolation of a portion of the NAO gene from an F. oxysporum genomic DNA preparation. This sequence was used to clone the cDNA for NAO from an F. oxysporum cDNA library. The sequence of the cloned cDNA showed that NOA is a member of the acyl-CoA dehydrogenase (ACAD) superfamily. The members of this family share with NAO a mechanism that is initiated by proton removal from carbon, suggesting a common chemical reaction for this superfamily. NAO was expressed in Escherichia coli and the recombinant enzyme was characterized. Recombinant NAO has identical kinetic parameters to enzyme isolated from F. oxysporum but is isolated with oxidized FAD rather than the nitrobutyl-FAD found in the fungal enzyme. NAO purified from E. coli or from F. oxysporum has no detectable ACAD activity on short- or medium-chain acyl CoAs, and medium-chain acyl-CoA dehydrogenase and short-chain acyl-CoA dehydrogenase are unable to catalyze oxidation of nitroalkanes

    Nonperturbative Determination of Heavy Meson Bound States

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    In this paper we obtain a heavy meson bound state equation from the heavy quark equation of motion in heavy quark effective theory (HQET) and the heavy meson effective field theory we developed very recently. The bound state equation is a covariant extention of the light-front bound state equation for heavy mesons derived from light-front QCD and HQET. We determine the covariant heavy meson wave function variationally by minimizing the binding energy Λˉ\bar{\Lambda}. Subsequently the other basic HQET parameters λ1\lambda_1 and λ2\lambda_2, and the heavy quark masses mbm_b and mcm_c can also be consistently determined.Comment: 15 pages, 1 figur

    O papel das instituições subnacionais na aderência da agenda de integração hídrica: lições da governança hídrica metropolitana de Curitiba

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    A escassez hídrica global tratada há décadas por documentos internacionais, é também reconhecida, ainda que com baixa aderência, nas agendas ambientais subnacionais. Conceitos como o Gerenciamento Integrado de Recursos Hídricos (GIRH) e Serviços Ecossistêmicos (SE) são relevantemente preconizados a nível internacional pela comunidade científica para serem aplicados pelas instituições no nível local. Este artigo propõe uma análise da adesão destes conceitos para a governança da água na Região Metropolitana de Curitiba (RMC). Primeiramente foram elencados os planos de maior relevância no gerenciamento da água na governança relativa ao Estado do Paraná e ao município de Curitiba, bem como suas respectivas atribuições com relação à manutenção desse recurso e suas escalas de atuação. As instituições envolvidas na gestão dos recursos hídricos na RMC dialogam de alguma forma com a agenda internacional? Por meio de uma análise documental, relacionamos as medidas adotadas pelos diferentes atores de modo a subsidiar uma análise da inserção dos conceitos de GIRH e SE nas suas respectivas atuações. Com isto buscou-se entender as possíveis implicações para o gerenciamento da água dentro das especificidades de governança paranaense e curitibana, e como as instituições e sua relação com o meio ambiente podem ter consequências sobre a disponibilidade de água com qualidade na RMC

    Prevalence and predictors of being lost to follow-up after transurethral resection of the prostate

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    Patient follow-up after transurethral resection of the prostate (TURP) is crucial to evaluate treatment-related outcomes and potential adverse events. We sought to determine the rate of, and factors associated with, patient nonadherence to follow-up after TURP. Data from 180 patients who underwent TURP were analysed. Patient counselling and follow-up were standardized among the cohort. Patients were considered lost to follow-up (LTF) if they were at least 30 days from their first scheduled follow-up appointment. Descriptive statistics and logistic regression analyses were performed to determine the impact of predictors on the rate of compliance with prescribed follow-up. Of 180 patients, 55 (30.5%) were LTF. LTF patients were younger (p < 0.001), had lower educational status (p = 0.007) and were more frequently single (p = 0.03) than those who were not LTF. Importantly, patients who experienced a postoperative-related event (PRE) were more likely to follow-up (p = 0.04). Multivariable analysis revealed that younger age (p < 0.001) and low educational status (p < 0.001) were independent predictors of being LTF. One out of three men submitted to TURP is lost to follow-up in the real-life setting. Noncompliance to follow-up was more frequent among young, single patients with low educational status. On the contrary, patients who experienced a PRE were more likely to follow-up

    pi-pi scattering in a QCD based model field theory

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    A model field theory, in which the interaction between quarks is mediated by dressed vector boson exchange, is used to analyse the pionic sector of QCD. It is shown that this model, which incorporates dynamical chiral symmetry breaking, asymptotic freedom and quark confinement, allows one to calculate fπf_\pi, mπm_\pi, rπr_\pi and the partial wave amplitudes in π\pi-π\pi scattering and obtain good agreement with the experimental data, with the latter being well described up to energies \mbox{E≃700E\simeq 700 MeV}.Comment: 23 Pages, 4 figures in PostScript format, PHY-7512-TH-93, REVTEX Available via anonymous ftp in /pub: login anonymou get pipi93.tex Fig1.ps Fig2.ps Fig3.ps Fig4.p

    Incidence and predictors of readmission within 30 days of transurethral resection of the prostate : a single center European experience

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    Hospital readmission rates have been analyzed due to their contribution to increasing medical costs. Little is known about readmission rates after urological procedures. We aimed to assess the incidence and predictors of 30-day readmission after discharge in patients treated with transurethral resection of the prostate (TURP). Data from 160 consecutive patients who underwent TURP from January 2015 to December 2016 were analysed. Intra hospitalization characteristics included length of stay (LOS), catheterization time (CT) and complications. Comorbidities were scored with the Charlson Comorbidity Index (CCI). Mean (SD) age was 70.1 (8.1) yrs and mean prostate volume was 80 (20.1) ml. Mean LOS and CT were 4.9 (2.5) days and 3.3 (1.6) days, respectively. The overall 30-day readmission rate was 14.4%, but only 7 (4.4%) patients required hospitalization. The most frequent reasons for readmission were haematuria (6.8%), fever/urinary tract infections (4.3%) and acute urinary retention (3.1%). Multivariable logistic regression analysis revealed age, CCI and CT to be independent predictors of readmission. However, when analysed according to age at the time of surgery, a beneficial effect from longer CT was observed only for patients older than 75 years. These parameters should be taken in account at the time of discharge after TURP

    Clinical comparison between conventional and microdissection testicular sperm extraction for non-obstructive azoospermia : understanding which treatment works for which patient

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    OBJECTIVES: The superiority of microdissection testicular sperm extraction (mTESE) over conventional TESE (cTESE) for men with non-obstructive azoospermia (NOA) is debated. We aimed to compare the sperm retrieval rate (SRR) of mTESE to cTESE and to identify candidates who would most benefit from mTESE in a cohort of Caucasian-European men with primary couple's infertility. MATERIAL AND METHODS: Data from 49 mTESE and 96 cTESE patients were analysed. We collected demographic and clinical data, serum levels of LH, FSH and total testosterone. Patients with abnormal karyotyping were excluded from analysis. Age was categorized according to the median value of 35 years. FSH values were dichotomized according to multiples of the normal range (N) (N and 1.5 N: 1-18 mIU/mL, and > 18 mIU/mL). Testicular histology was recorded for each patient. Descriptive statistics and logistic regression analyses tested the impact of potential predictors on positive SRR in both groups. RESULTS: No differences were found between groups in terms of clinical and hormonal parameters with the exception of FSH values that were higher in mTESE patients (p = 0.004). SRR were comparable between mTESE and cTESE (49.0% vs. 41.7%, p = 0.40). SRRs were significantly higher after mTESE in patients with Sertoli cell-only syndrome (SCOS) (p = 0.038), in those older than 35 years (p = 0.03) and with FSH >1.5N (p 1.5N (p = 0.018). Moreover, increased FSH levels (p = 0.03) and both SCOS (p = 0.01) and MA histology (p = 0.04) were independent predictors of SRR failure. CONCLUSIONS: Microdissection and cTESE showed comparable success rates in our cohort of patients with NOA. mTESE seems beneficial for patients older than 35 years, with high FSH values, or when SCOS can be predicted. Given the high costs associated with the mTESE approach, the identification of candidates most likely to benefit from this procedure is a major clinical need
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