Avaliação da gordura hepática utilizando ressonância magnética

A esteatose hepática, que se caracteriza pelo acúmulo excessivo de gordura nas células do fígado, é um problema que vem preocupando a comunidade médico-científica, pois sua incidência vem aumentando a nível global, com expectativa de se tornar a doença crônica hepática de maior predominância em várias partes do mundo. Apesar de ser considerada uma doença benigna, a esteatose pode evoluir para doenças mais graves como cirrose, fibrose avançada, esteato hepatite (com ou sem fibrose) ou carcinoma. Entretanto, é potencialmente reversível, mesmo em quadros mais graves, o que reforça a urgência de se desenvolver métodos confiáveis para detecção e avaliação, inclusive ao longo de tratamento. Os métodos atuais para diagnóstico e quantificação da gordura hepática ainda são falhos: com a ultrassonografia não se é capaz de realizar quantificação; a tomografia computadorizada faz uso de radiação ionizante; a punção (biópsia), considerada o padrão ouro, é precisa, mas invasiva e pontual. A Ressonância Magnética (RM), tanto com espectroscopia (MRS) como com imagem (MRI), são alternativas completamente não invasivas, capazes de fornecer o diagnóstico e quantificação da gordura infiltrada no fígado. Entretanto, os trabalhos encontrados na literatura utilizam sequências de pulsos desenvolvidas especialmente para esse fim, com métodos de pós-processamento extremamente rebuscados, o que não é compatível com o estado atual dos equipamentos encontrados em ambientes clínicos nem mesmo ao nível de experiência e conhecimento das equipes técnicas que atuam em clínicas de radiodiagnóstico. Assim, o objetivo central do presente trabalho foi avaliar o potencial da RM como candidato a método de diagnóstico e de quantificação de gordura em ambientes clínicos, utilizando, para isso, sequências de pulsos convencionais, disponíveis em qualquer sistema comercial de RM, com protocolos de aquisição e processamento compatíveis com àqueles realizados em exames clínicos, tanto no que se refere à simplicidade como ao tempo total de aquisição. Foram avaliadas diferentes abordagens de MRS e MRI utilizando a biópsia hepática como padrão de referência. Foram avaliados pacientes portadores de diabetes tipo II, que apresentam alta prevalência de esteatose hepática não alcoólica, além de grande variabilidade nos percentuais de gordura. Foram realizadas medidas de correlação, acurácia, sensibilidade e especificidade de cada uma das abordagens utilizadas. Todos os métodos avaliados apresentaram alto grau de correlação positiva (> 87%) com os dados obtidos de maneira invasiva, o que revela que os valores obtidos utilizando RM estão de acordo com aquilo observado pela biópsia hepática. Muito embora os métodos de processamento utilizados não sejam tão complexos quanto seriam necessários caso uma quantificação absoluta fosse desejada, nossas análises mostraram alta acurácia, especificidade e sensibilidade da RM na avaliação da esteatose. Em conclusão, a RM se apresenta, de fato, como uma excelente candidata para avaliar, de forma não invasiva, a fração de gordura hepática, mesmo quando se considera as limitações impostas por um ambiente clínico convencional. Isso sugere que essas novas metodologias podem começar a migrar para ambientes clínicos sem depender das sequências complexas e dos processamentos exóticos que estão descritos na literatura mais atual.

Análise comparativa de enxertos de gordura em refinamentos de reconstrução mamária com e sem suplementação de células-tronco

INTRODUÇÃO: Os enxertos de gordura tem se mostrado como uma poderosa técnica cirúrgica em reconstrução mamaria secundária e os enxertos enriquecidos com células-tronco, além de suas ações parácrinas, vem apresentando resultados encorajadores no que tange a persistência volumétrica. OBJETIVO: Este estudo clínico teve como objetivo analisar comparativamente quantitativa e qualitativamente enxertos de gordura enriquecidos com células da fração vásculoestromal em reconstrução mamária secundária e a incidência de complicações. MÉTODO: Nós desenvolvemos um método que produz enxertos de gordura, na sala de cirurgia, em uma taxa de enriquecimento maior que os já publicados (2:1). Este estudo clínico prospectivo e controlado analisou qualitativa e quantitativamente enxertos de gordura com (GT - grupo tronco) e sem (GC - grupo controle) adição das células da fração vásculo-estromal fresca em reconstrução mamária secundária; através de volumetria mamária por RNM de mamas, imunofenotipagem e contagem celular. Também foram estudados os resultados estéticos, a satisfação das pacientes e as complicações. RESULTADOS: A persistência volumétrica no GT foi 78,9% e 51,4% no GC, entretanto não houve diferença estatisticamente significativa entre os grupos. CD90 foi o marcador mais expresso e que alcançou diferença significante e ao mesmo tempo apresentou correlação positiva entre a sua expressão e a persistência volumétrica (r=0.651, p=0.03). Necrose gordurosa ocorreu, isoladamente em 4 pacientes do GT submetidas à radioterapia e nenhuma paciente do GC apresentou este evento. Desta forma, pacientes do GC mostraram tendência de estar mais satisfeitas com o enxerto de gordura. Nos dois grupos, os resultados estéticos foram iguais e não foram observadas recidivas loco-regionais. CONCLUSÃO: Os resultados do enriquecimento em uma taxa maior que as já publicadas são encorajadores, apesar de a persistência volumétrica não ter alcançado diferença estatisticamente significante entre os grupos. Enxertos de gordura enriquecidos na proporção 2:1 podem não ser indicados para pacientes submetidas à radioterapia apesar de terem se mostrados seguros num tempo de seguimento de 3 anos

Croatia and the structural funds – Doing without an Ottoman Empire bypass bridge. CEPS Commentary, 29 July 2013

In his latest commentary, Associate Senior Fellow Michael Emerson hails Croatia’s accession to the EU as a fine step forward towards the official goal of integration of the whole of the Balkans into the EU. At the same time, he warns of the folly underway of the serious attention being paid by the European Commission to the newest member state’s petition to construct a multi-million euro bridge over a 9-km stretch of Bosnian land (the ‘Neum corridor’) that inconveniently but temporarily interrupts a non-stop drive along Croatia’s Dalmatian coast.

Down the road to Dubrovnik – Doing without an Ottoman Empire bypass bridge. CEPS Commentary, 29 July 2013

As Europeans speed down the road to Dubrovnik, Croatia's treasured jewel of the Adriatic coast, Michael Emerson discusses in a seasonal commentary one topical issue: What to do now over the 9 km of Bosnian coastline that separates north and south Croatia? Several options are under consideration, one of which would mean a very expensive bridge and dubious use of EU structural funds.

Transport of dredged sediment placed in the nearshore zone--Currituck sand-bypass study (phase I) /

New dredge-disposal techniques may serve the dual role of aiding sand by-passing across coastal inlets, and beach nourishment, provided the dredged sediments placed seaward of the surf zone move shoreward into that zone. During the summer of 1976, 26,750 cubic meters of relatively coarse sediment was dredged from New River Inlet, North Carolina, moved down coast by a split-hull barge, and placed in a 215-meter coastal reach between the 2- and 4-meter depth contours. Bathymetric changes on the disposal piles and in the adjacent beach and nearshore area were studied for a 13-week period (August to November 1976) to determine the modification of the surrounding beach and nearshore profile, and the net transport direction of the disposal sediment. The sediment piles initially created a local shoal zone with minimum depths of 0.6 meter. Disposal sediment was coarser (Mn = 0.49 millimeter) than the native sand at the disposal site (Mn = 0.14 millimeter) and coarser than the composite mean grain size of the entire profile (Mn = 0.21 millimeter). Shoaling and breaking waves caused rapid erosion of the pile tops and a gradual coalescing of the piles to form a disposal bar located seaward (= 90 meters) of a naturally occurring surf zone bar. As the disposal bar relief was reduced, the disposal bar-associated breaker zone was restricted to low tide times or periods of high wave conditions.

Coronary bypass surgery in Illinois.

Description based on: 1993.

Evaluation of the Moanalua Freeway carpool/bus bypass lane /

Mode of access: Internet.

A comparison of competing methods for the detection of surgical-site infections in patients undergoing total arthroplasty of the knee, partial and total arthroplasty of hip and femoral or similar vascular bypass

Recent research suggests that the retrospective review of the International Classification of Disease (ICD-9-CM) codes assigned to a patient episode will identify a similar number of healthcare-acquired surgical-site infections as compared with prospective surveillance by infection control practitioners (ICP). We tested this finding by replicating the methods for 380 surgical procedures. The sensitivity and specificity of the ICP undertaking prospective surveillance was 80% and 100%, and the sensitivity and specificity of the review of ICD-10-AM codes was 60% and 98.9%. Based on these results we do not support retrospective review of ICD-10-AM codes in preference prospective surveillance for SSI. (C) 2004 The Hospital Infection Society. Published by Elsevier Ltd. All rights reserved.

Vascular engineering for bypass surgery

Since the introduction of synthetic vascular grafts in the 1960s, only two-stage endothelial cell seeding has demonstrated any significant improvement over conventional vascular grafts, and its benefits have yet to be demonstrated on a large scale. Tissue engineering is a rapidly expanding field with great potential, but efforts to construct tissue-engineered arterial grafts have, to date, yielded little clinical success. This review explores the latest approaches to the construction of a superior vascular graft, along with its potential for use in the clinic in the future.

Asymptomatic long-term survivors of coronary artery bypass surgery enjoy a quality of life equal to the general population

Background Health-related quality of life (HRQOL) among long-term survivors of coronary artery bypass surgery is an important outcome that has been little studied at the population level. Methods A postal survey was conducted in 1999 to 2000 in patients 6 to 20 years after coronary artery bypass graft (CABG) surgery in Western-Australia. A random stratified sample of 2500 was drawn from 8910 patients who had their first CABG surgery in 1980 to 1993. Health-related quality of life was measured with Short Form 36 and EuroQol visual analogue scale. Results Response was 82% (n = 2061). Health-related quality of life declined with age and was similar for men and women, although scores for women were worse for physical functioning. Compared with Australian population norms, the age- and sex-standardized scores of survivors of CABG were generally worse, mainly in the physical domain. Reported angina at the time of follow-up (33%), symptoms of heart failure equivalent to New York Heart Association (NYHA) classes II to IV (34%), and comorbidities such as diabetes and hypertension were associated with poorer HRQOL. For both men and women without angina or heart failure at follow-up, HRQOL was no different from that of the general population. Conclusion Overall, the quality of life among long-term survivors of CABG is worse than that of the general population, the difference being mainly attributable to recurrent symptoms and comorbidities. Quality of life for those without angina or heart failure at follow-up was equivalent to the population norms, providing an incentive to maximize efforts to abolish angina and ameliorate heart failure symptoms.

A comparison of the effect of high- and low-dose fentanyl on the incidence of postoperative cognitive dysfunction after coronary artery bypass surgery in the elderly

Background. Postoperative cognitive dysfunction (POCD) after coronary artery bypass graft surgery is a common complication for which, despite many clinical investigations, no definitive etiology has been found. The current use of both high and low-dose fentanyl as anesthetic techniques allowed us to investigate the effect of fentanyl on the incidence of POCD. Methods. Three hundred fifty patients scheduled to undergo elective coronary artery bypass graft surgery were randomized to receive either high-dose fentanyl (50 mu g/kg) or low-dose fentanyl (10 mu g/kg) as the basis of the anesthetic. All patients underwent neuropsychological testing before surgery and at 1 week, 3 months, and 12 months after surgery. Results. One hundred sixty-eight patients in the low-dose group and 158 patients in the high-dose group were included in the final analysis. Neuropsychological testing was performed on 88%, 93%, and 92% of patients at 1 week, 3 months, and 12 months, respectively. There was no difference between group mean scores at any of the three testing times. Analysis of individual patients by the 20% rule did not detect any differences between groups. The one SD rule, which has fewer false-positive results, detected significantly more patients with POCD in the low-dose group than in the high-dose group at 1 week (23.6% vs. 13.7%; P = 0.03) but not at the other testing times. Patients with POCD spent an average of 1.2 days longer in the hospital than those without POCD (P = 0.021). Conclusions: High-dose fentanyl is not associated with a difference in the incidence of POCD at 3 or 12 months after surgery. Low-dose fentanyl leads to shorter postoperative ventilation times and may be associated with a greater incidence of POCD 1 week after surgery. Early POCD is associated with an increased duration of stay in the hospital.

PhotoVoltaic DC-DC module integrated converter for novel cascaded and bypass grid connection topologies - design and optimisation

Grid connected PhotoVoltaic (PV) inverters fall into three broad categories — Central, String and Module Integrated Converers (MICs). MICs offer any avantaes in performance and flexibility, but are at a cost disadvantage. Two alternative novel approaches proposed by the author — cascaded dc-dc MICs and bypass dc-dc MICs — integrate a simple non-isolated intelligent dc-dc converter with each PV module to provide the advantages of dc-ac MICs at a lower cost. A suitable universal 150W 5A dc-dc converter design is presented based on two interleaved MOSFET half bridges. Testing shows Zero Voltage Switching (ZVS) keeps losses under 1W for bi-directional power flows up to 15W between two adjacent 12V PV modules for the bypass application, and efficiencies over 94% for most of the operational power range for the cascaded converter application. Based on the experimental results, potential optimizations to further reduce losses are discussed.

Free radical reaction products and antioxidant capacity in beating heart coronary artery surgery compared to conventional bypass

Oxygen-derived free radicals are important agents of tissue injury during ischemia and reperfusion. The aim of this study was to investigate changes in protein and lipid oxidation and antioxidant status in beating heart coronary artery surgery and conventional bypass and to compare oxidative stress parameters between the two bypass methods. Serum lipid hydroperoxide, nitric oxide, protein carbonyl, nitrotyrosine, vitamin E, and β-carotene levels and total antioxidant capacity were measured in blood of 30 patients undergoing beating heart coronary artery surgery (OPCAB, off-pump coronary artery bypass grafting) and 12 patients undergoing conventional bypass (CABG, on-pump coronary artery bypass grafting). In the OPCAB group, nitric oxide and nitrotyrosine levels decreased after reperfusion. Similarly, β-carotene level and total antioxidant capacity also decreased after anesthesia and reperfusion. In the CABG group, nitric oxide and nitrotyrosine levels decreased after ischemia and reperfusion. However, protein carbonyl levels elevated after ischemia and reperfusion. Vitamin E, β-carotene, and total antioxidant capacity decreased after ischemia and reperfusion. Significantly decreased nitration and impaired antioxidant status were seen after reperfusion in both groups. Moreover, elevated protein carbonyls were found in the CABG group. The off-pump procedure is associated with lower degree of oxidative stress than on-pump coronary surgery. © 2011 Pleiades Publishing, Ltd.