Parâmetros dopplervelocimétricos na avaliação da perviedade da anastomose portossistêmica intra-hepática transjugular (TIPS) Dopplerflowmetric patterns for evaluation of transjugular intrahepatic portosystemic shunt patency

A anastomose portossistêmica intra-hepática transjugular (TIPS) é um procedimento intervencionista minimamente invasivo realizado pela introdução de prótese metálica auto-expansível no parênquima hepático, via transjugular. Tem por objetivo tratar as complicações da hipertensão portal, principalmente a hemorragia digestiva alta e a ascite refratária. A estenose é complicação freqüente, embora o procedimento seja eficaz e com baixo índice de insucesso. O diagnóstico precoce da estenose é de fundamental importância, pois interfere no tipo de tratamento a ser realizado e o reaparecimento dos sintomas pode ser grave. O ultra-som Doppler é então utilizado para o seguimento dos pacientes portadores do TIPS, e vários parâmetros são descritos na literatura para o diagnóstico de estenose, como: as velocidades mínima e máxima no interior da prótese, a velocidade na veia porta, o gradiente de velocidade entre dois pontos da prótese, e outros. Infelizmente não há consenso sobre qual parâmetro ou conjunto de parâmetros é mais eficaz no diagnóstico, porque os protocolos de avaliação variam de instituição para instituição. Os autores realizaram uma revisão dos parâmetros de estenose descritos na literatura e de outros aspectos de fundamental importância na compreensão do procedimento, como as indicações, as contra-indicações e a fisiopatologia da estenose.<br>Transjugular intrahepatic portosystemic shunt (TIPS) is a minimally invasive interventional procedure that consists of placement of an auto expandable metallic stent in the hepatic parenchyma via transjugular. It is used to treat the complications of portal hypertension, particularly digestive bleeding of gullet varices and refractory ascites. Although TIPS is an efficient procedure with low rate of failure some complications such as stenosis are frequent. Early diagnosis of stenosis is mandatory since it interferes with the type of treatment and the reappearing symptoms can be serious. Doppler sonography is used in the follow-up of this patients and many parameters indicating TIPS stenosis are described in the literature such as the minimum and maximum velocity flow inside the stent, the velocity flow in portal vein, the velocity gradient between different sites of the stent, among others. Unfortunately there is no consensus on which parameter or group of parameters is more efficient for diagnosis because the evaluation protocols varied among institutions. The authors reviewed the parameters of stenosis reported in literature and other important aspects for comprehension of this procedure including indications, contraindications and physiopathology of stenosis

Guidelines for the use and interpretation of assays for monitoring autophagy (4th edition)

In 2008, we published the first set of guidelines for standardizing research in autophagy. Since then, this topic has received increasing attention, and many scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Thus, it is important to formulate on a regular basis updated guidelines for monitoring autophagy in different organisms. Despite numerous reviews, there continues to be confusion regarding acceptable methods to evaluate autophagy, especially in multicellular eukaryotes. Here, we present a set of guidelines for investigators to select and interpret methods to examine autophagy and related processes, and for reviewers to provide realistic and reasonable critiques of reports that are focused on these processes. These guidelines are not meant to be a dogmatic set of rules, because the appropriateness of any assay largely depends on the question being asked and the system being used. Moreover, no individual assay is perfect for every situation, calling for the use of multiple techniques to properly monitor autophagy in each experimental setting. Finally, several core components of the autophagy machinery have been implicated in distinct autophagic processes (canonical and noncanonical autophagy), implying that genetic approaches to block autophagy should rely on targeting two or more autophagy-related genes that ideally participate in distinct steps of the pathway. Along similar lines, because multiple proteins involved in autophagy also regulate other cellular pathways including apoptosis, not all of them can be used as a specific marker for bona fide autophagic responses. Here, we critically discuss current methods of assessing autophagy and the information they can, or cannot, provide. Our ultimate goal is to encourage intellectual and technical innovation in the field