Omentum facilitates liver regeneration.
ABSTRACT To investigate the mechanism of liver regeneration induced by fusing the omentum to a small traumatic injury created in the liver. We studied three groups of rats. In one group the rats were omentectomized; in another group the omentum was left in situ and was not activated, and in the third group the omentum was activated by polydextran particles.
We pre-activated the omentum by injecting polydextran particles and then made a small wedge wound in the rat liver to allow the omentum to fuse to the wound. We monitored the regeneration of the liver by determining the ratio of liver weight/body weight, by histological evaluation (including immune staining for cytokeratin-19, an oval cell marker), and by testing for developmental gene activation using reverse transcription polymerase chain reaction (RT-PCR).
There was no liver regeneration in the omentectomized rats, nor was there significant regeneration when the omentum was not activated, even though in this instance the omentum had fused with the liver. In contrast, the liver in the rats with the activated omentum expanded to a size 50% greater than the original, and there was histologically an interlying tissue between the wounded liver and the activated omentum in which bile ducts, containing cytokeratin-19 positive oval cells, extended from the wound edge. In this interlying tissue, oval cells were abundant and appeared to proliferate to form new liver tissue. In rats pre-treated with drugs that inhibited hepatocyte growth, liver proliferation was ongoing, indicating that regeneration of the liver was the result of oval cell expansion.
Activated omentum facilitates liver regeneration following injury by a mechanism that depends largely on oval cell proliferation.
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ABSTRACT: The mobile world's rapid growth has spurred development of new protocols and new algorithms to meet changing operating requirements, such as mobile networking and quality-of-service support. Handoff is one of the most critical procedures in cellular systems. Network operators give emphasis to optimizing handover, since it is strongly related to dropped calls, network overload and, consequently, users' criticism. Handoff can be seen as a blind procedure, if it is only based on the comparison of measurements, without information of location. Since signal propagation and path-loss are complex in nature, we can expect unnecessary and wrong handoff executions. Both UMTS and second generation (GSM) systems require redefined handoff algorithms for active connections as smooth mobility support and continuous connection are essential issues for obtaining high performance and increasing user satisfaction. We present a set of intelligent algorithms using mobile terminal (MT) location information and area awareness to assist safe handoff decisions. The implemented algorithms are validated by means of cellular network simulators that clearly show the impact of these techniques to major system performance metrics.Vehicular Technology Conference, 2004. VTC 2004-Spring. 2004 IEEE 59th; 06/2004
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ABSTRACT: Adipose tissue is a major site of chronic inflammation associated with peritoneal dialysis (PD) frequently complicating peritonitis. Adiposity-associated inflammation plays a significant contributory role in the development of chronic inflammation in patients undergoing maintenance PD. However, the molecular and cellular mechanisms of this link remain uncertain. Adipose tissue synthesizes different adipokines and cytokines that orchestrate and regulate inflammation, insulin action, and glucose metabolism locally and systemically. In return, inflammation retards adipocyte differentiation and further exacerbates adipose dysfunction and inflammation. An understanding of the inflammatory roles played by adipose tissue during PD and the healing mechanism of injured mesothelium will help to devise new therapeutic approach to slow the progression of peritoneal damage during peritoneal dialysis. This article reviews the roles of peritoneal adipose tissue in chronic peritoneal inflammation under PD and in serosal repair during PD.Mediators of Inflammation 01/2010; 2010:495416. DOI:10.1155/2010/495416 · 2.42 Impact Factor
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ABSTRACT: Today, many patients suffer from acute liver failure and hepatoma. This is an area of high unmet clinical need as these conditions are associated with very high mortality. There is an urgent need to develop techniques that will enable liver tissue engineering or generate a bioartificial liver, which will maintain or improve liver function or offer the possibility of liver replacement. Liver tissue engineering is an innovative way of constructing an implantable liver and has the potential to alleviate the shortage of organ donors for orthotopic liver transplantation. In this review we describe, from an engineering perspective, progress in the field of liver tissue engineering, including three main aspects involving cell sources, scaffolds and vascularization.Cytotherapy 05/2010; 12(3):349-60. DOI:10.3109/14653240903479655 · 3.10 Impact Factor