Publications by authors named "Seiichi Son"

[Purpose] In gastric cancer patients, low muscle mass decreases overall survival and quality of life (QOL). Resistance exercise with leucine-enriched essential amino acid (LEAA) supplementation may prevent muscle mass loss. This study was aimed at determining whether resistance exercise with LEAA supplementation prevents muscle mass loss in post-gastrectomy patients.

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Background/aims: Evaluation of preoperative hepatic reserve is critical to avoid a fatal clinical course such as liver failure. We retrospectively evaluated 158 consecutive hepatocellular carcinoma (HCC) patients who underwent initial hepatectomy. The aim of this study was to determine the correlations of multiple indicators for assessment of liver function before hepatectomy.

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In human pancreatic cancer, integral membrane proteins of tight junction claudins are abnormally regulated, making these proteins promising molecular diagnostic and therapeutic targets. However, the regulation of claudin-based tight junctions remains unknown not only in the pancreatic cancer cells but also in normal human pancreatic duct epithelial (HPDE) cells. To investigate the regulation of tight junction molecules including claudins in normal HPDE cells, we introduced the human telomerase reverse transcriptase (hTERT) gene into HPDE cells in primary culture.

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Tight junctions of hepatocytes play crucial roles in the barrier to keep bile in bile canaliculi away from the blood circulation, which we call the blood-billiary-barrier (Kojima et al., 2003). Tight junction proteins of hepatocytes are regulated by various cytokines and growth factors via distinct signal transduction pathways.

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The polarization of hepatocytes involves formation of functionally distinct sinusoidal (basolateral) and bile canalicular (apical) plasma membrane domains that are separated by tight junctions. Although various molecular mechanisms and signaling cascades including polarity complex proteins may contribute to bile canalicular formation in hepatocytes, the role of tight junction proteins in bile canalicular formation remains unclear. To investigate the role of the integral tight junction protein claudin-2 in bile canalicular formation, we depleted claudin-2 expression by siRNA in the polarized hepatic cell line WIF-B9 after treatment with or without phenobarbital.

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Background/aims: Transforming growth factor-beta (TGF-beta) initiates and maintains epithelial-mesenchymal transition (EMT), which causes disassembly of tight junctions and loss of epithelial cell polarity. In mature hepatocytes during EMT induced by TGF-beta, changes in the expression of tight junction proteins and the fence function indicated that epithelial cell polarity remains unclear.

Methods: In the present study, using primary cultures of adult rat hepatocytes at day 10 after plating, in which epithelial cell polarity is well maintained by tight junctions, we examined the effects of 0.

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In rodent livers, integral tight junction (TJ) proteins claudin-1, -2, -3, -5 and -14 are detected and play crucial roles in the barrier to keep bile in bile canaculi away from the blood circulation. Claudin-2 shows a lobular gradient increasing from periportal to pericentral hepatocytes, whereas claudin-1 and -3 are expressed in the whole liver lobule. Although claudin-2 expression induces cation-selective channels in tight junctions of epithelial cells, the physiological functions and regulation of claudin-2 in hepatocytes remain unclear.

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