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Background A precondition for the successful formation of tissue-engineered heart valves is the generation of a proper matrix on biodegradable scaffolds over a limited period of time. The aim of this study was to find an effective method of seeding autologous cells on these scaffolds to create a new matrix for heart valves. Methods Myofibroblasts and endothelial cells were isolated and cultured from an ovine artery. A synthetic biodegradable scaffold consisting of polyglycolic and polylactic acids was seeded first with the myofibroblasts, then coated with endothelial cells. Three different methods of myofibroblast seeding were compared: I) daily seeding of myofibroblasts (1×106) for ten days and culture for four days; II) seeding of myofibroblasts (1×107) and culture for 14 days with the use of a simple medium; III) seeding of myofibroblasts (1×107) with the use of a medium containing collagen and culture for 14 days. Light and electron microscopic analyses were perfomed. Results The group that used the medium containing collagen showed the best results in terms of seeding efficiency. Conclusion Seeding autologous cells with a medium containing collagen onto the scaffold showed the largest cell population and might generate the best matrix on the scaffold.

We report the case of a 64-year-old man who presented with a hepatic mass and macronodular cirrhosis. The pathologic findings revealed a lymphoepithelioma-like carcinoma arising in the hepatobiliary tract that was morphologically identical to nasopharyngeal undifferentiated carcinoma. However, this tumor was not associated with Epstein-Barr virus infection in molecular studies. Macronodular cirrhosis associated with hepatitis C virus was present in the background liver.

Dysplastic nodules (DNs) recently have been identified as preneoplastic lesions of hepatocellular carcinoma (HCC). To test an alternative hypothesis regarding DN development, in which we have suggested that DNs develop as an infiltrating clonal expansion in advance of, or parallel to cirrhosis, the authors investigated the rates of apoptosis and proliferation in human hepatocarcinogenesis.The authors performed terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL) assay and proliferation cell nuclear antigen (PCNA) staining in 11 low-grade DNs, 8 high-grade DNs including 3 cases with HCC subnodules, 10 small HCCs, and 29 cases of surrounding cirrhotic nodules. Hepatocellular carcinoma subnodules were present in three cases of high DNs. They determined TUNEL-labeling indices (LIs) and PCNA-LIs as the percentage of positive hepatocyte nuclei per 500 randomly counted cells.TUNEL-LIs (mean +/- standard deviation) were 0.8 +/- 0.82 in cirrhotic nodules, 1.0 +/- 0.98 in low-grade DNs, 3.0 +/- 4.33 in high-grade DNs, 8.7 +/- 7.71 in HCC subnodules of high-grade DNs, and 3.2 +/- 3.58 in small HCCs. The peak values of apoptotic activity were higher in high-grade DNs and HCCs than in low-grade DNs and cirrhotic nodules. Each case of low-grade DN showed a low to medium level of apoptotic activity when compared with those of the four surrounding cirrhotic nodules. The PCNA-LIs were 2.6 +/- 1.35 in cirrhotic nodules, 4.5 +/- 2.31 in low-grade DNs, 15.3 +/- 10.50 in high-grade DNs, 25.4 +/- 5.25 in HCC subnodules of high-grade DNs, and 34.9 +/- 15.70 in small HCCs. The peak values gradually increased, although only HCC showed significantly elevated proliferation activity. The differences of PCNA-LIs and TUNEL-LIs, measured in each case, were 1.7 +/- 1.89 in cirrhotic nodules, 3.6 +/- 2.43 in low-grade DNs, 7.9 +/- 5.69 in high-grade DNs, 16.2 +/- 2.87 in HCC subnodules of high-grade DNs, 28.2 +/- 13.97 in small HCCs. At all stages of hepatocarcinogenesis, the rates of cell proliferation were higher than apoptosis, allowing a preferential net gain of (pre)neoplastic cells, and it was significantly increased in small HCCs. In regenerative cirrhotic nodules, 14% (4 cases) showed higher rates of apoptosis than proliferation.The regulation/dysregulation of apoptosis of (pre)neoplastic cells as well as of proliferation may play an important role in the process of hepatocarcinogenesis.

Transcatheter arterial embolization induces extensive ischaemic necrosis or hypoxia via the obstruction of the hepatic artery in hepatocellular carcinoma (HCC). Ischaemia is strongly correlated with an increased expression of angiogenic factor and stimulates an increase in angiogenesis, including endothelial cell proliferation. The aim of this study was to evaluate whether ischaemic necrosis induced by transcatheter arterial embolization could increase the proliferative activities of intratumoral endothelial cells or tumour cells in the residual HCC.Using a double immunohistochemical technique (Ki67 antibody to determine the proliferative activity and CD34 antibody to highlight the intratumoral endothelial cells), we performed immunohistochemical staining for 24 HCCs treated by transcatheter arterial embolization. Seven HCCs without any preoperative transcatheter arterial embolization and nine cirrhosis cases were also studied as the control cases. The residual tumour was then divided into five areas at 0.5 mm intervals, according to the distance from the necrotic margin induced by embolization. The Ki67 labelling indices of the intratumoral endothelial cells and tumour cells were counted in each area. The correlation between the indices and the corresponding distance from the ischaemic necrosis was analysed. The Ki67 labelling index of intratumoral vascular endothelial cells in the area less than 0.5 mm from the necrotic margin (area 1) was 10.60 +/- 3.64% (mean +/- SD), which was twofold greater than those of the other areas more than 0.5 mm from the margin (areas 2--5) and those of the control HCCs without preoperative transcatheter arterial embolization. In addition, the proliferation labelling index of the tumour cells was 35.77 +/- 11.45% (mean +/- SD) in area 1. This was higher than those of areas 2--5 and control HCCs without preoperative transcatheter arterial embolization. There was a positive correlation between the proliferation of both endothelial and tumour cells and ischaemic necrosis (P0.05).Our study suggests that the proliferative activity of intratumoral endothelial cells and tumour cells is increased by ischaemic necrosis induced by transcatheter arterial embolization, and its effect is maximal in the area adjacent to the necrosis (less than 0.5 mm from the necrotic margin).

The biliary tract has neuroendocrine cells of endoderm origin similar to the gastrointestinal tract, however neuroendocrine tumors of the biliary tract are rare. We report a composite glandular-endocrine cell carcinoma of the common bile duct in a 64-year-old Korean man which was associated with Clonorchis sinensis. The patient complained of right upper quadrant abdominal pain. Several parasites of Clonorchis sinensis were removed during the percutaneous transbiliary drainage. Endoscopic retrograde cholangiopancreatography revealed a polypoid mass (3 x 3 cm) with central ulceration in the common bile duct. Pancreaticoduodenectomy was performed. Microscopic examination of the tumor revealed a composite small cell neuroendocrine carcinoma and adenocarcinoma. The small cell carcinoma component showed positive reaction to chromogranin A and neuron-specific enolase and it was located mainly in the deeper portion of the mass. The well-differentiated adenocarcinoma component showed a positive reaction to carcinoembryonic antigen and it was situated in the superficial portion of the mass. Exclusively, the small cell component metastasized to the lymph node. It is suggested that this tumor could arise from a multipotential stem cell and showed neuroendocrine and glandular differentiation and that Clonorchis sinensis could be a predisposing factor, as in cholangiocarcinoma.