Increasing evidence has indicated that perturbation of cyclins is one of the major factors leading to cancer. The aim of this study was not only to investigate various cell cycle-related kinase activities in hepatocellular carcinoma (HCC), but also to analyze the difference of cell cycle-related kinase activity levels between hepatitis C virus (HCV)-induced HCC and HCVinduced cirrhosis. The protein levels of cyclins D1, E, A, and H, and of cyclin dependent kinase 1 (Cdk1), Cdk2, Cdk4, Cdk6, and Cdk7 in HCC and in surrounding nontumorous cirrhosis were determined by Western blot. The enzymatic activities of cyclins D1, E, A, Cdk1, Cdk4, Cdk6, Cdk7, and Wee1 were measured using in vitro kinase assays. Protein levels and kinase activities of cyclin D1, Cdk4, cyclin E, cyclin A, and Wee1 were significantly elevated in HCC compared with surrounding cirrhotic tissues. The enhanced cyclin D1-related kinase activity in HCC was accompanied by the up-regulation of Cdk4 activity, but not Cdk6 activity. The kinase activities of Cdk6, Cdk7, and Cdk1 did not differ between HCC and surrounding cirrhotic tissues. In addition, the protein levels and kinase activities of cyclin D1, Cdk4, and cyclin E were higher in poorly differentiated HCC and advanced HCC. In conclusion, the increases of cyclin D1, Cdk4, cyclin E, cyclin A, and Wee1 play an important role in the development of HCC from cirrhosis. Cyclin D1, Cdk4, and cyclin E activation may be closely related to the histopathologic grade and progression of HCC. R ecent studies, including our research, have revealed that the deranged expression of cell cyclerelated proteins is one of the major factors contributing to hepatocellular carcinoma (HCC) development. 1-6 Here we investigated biochemical differences of various cell cycle-related kinase activities and protein levels in cirrhosis and HCC.Specific cyclin/cyclin-dependent kinase (Cdk) complexes are activated at different intervals during the cell cycle. 7-15 Cyclin D1/Cdk4 and cyclin D1/Cdk6 are activated in mid-G1 (Fig. 1, phase 1), whereas cyclin E/Cdk2 complexes are required for the G1/S transition (Fig. 1, phase 2), cyclin A/Cdk2 for the progression of DNA synthesis (Fig. 1, phase 3), and cyclin A-B/Cdk1 for the G2/M transition (Fig. 1, phase 4) of mitosis. The activation of cyclin D1/Cdk4 and cyclin D1/Cdk6 complexes at mid-G1 is responsible for the phosphorylation of retinoblastoma protein (pRb), and 2 Rb related proteins, p107, and p130. Members of the pRb family form complexes with transcription factors of the E2F family. 16 This interaction with pRb family members blocks the transcriptional activity of E2Fs; the complexes formed also function as active transcriptional repressor complexes at the promoters of some cell cycle genes. Phosphorylation of the pRb family inhibits the interaction with E2F family transcription factor and permits the expression of genes necessary for S-phase entry (cyclin A, proliferating cell nuclear antigen, and so on). 17 The expression of cyclins E and A at mid-to late-G1 permits the form...

Light and electron microscopic changes in human liver cells which were considered to be precancerous lesions, were studied. In our micrometrical examination, dysplastic liver cells were classified into two types: large and small dysplastic cell. Each type had nuclear pleomorphism and multinucleation; however, the nucleocytoplasmic ratio of the large dysplastic cell remained normal. Electron microscopically, the large dysplastic cell had some features of regenerative cells. The nucleocytoplasmic ratio of the small dysplastic cell was between that of normal hepatocytes and liver cancer cells. The difference in the incidence of the small and large dysplastic cells in normal livers and cirrhotic livers having hepatocellular carcinoma was statistically significant. In addition, the small dysplastic cell had more of a tendency to produce a small round focus. It was morphologically suggested that the more important candidate for the precancerous cell in the liver was the small dysplastic cell.

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Annexin (AX) constitutes a new family of Ca2+-dependent membrane-binding proteins; 13 of them have been described. Among these, annexin-1 (AX-I) has displayed many biological functions in vitro. Its actual role in vivo, however, remains unknown. We already reported that AX-I was expressed in proliferating (regenerating) hepatocytes at both protein and messenger RNA (mRNA) levels. The role of AX-I in human hepatocellular carcinoma (HCC) remains obscure. In this study, the amounts of AX-I at protein and mRNA levels, as well as its localization, have been determined in the normal human liver, chronic hepatitis liver, and nontumorous and tumorous portions of HCC. AX-I was rarely found in normal and chronic liver tissues, whereas it is overexpressed at both the transcriptional and translational levels in tumorous and nontumorous regions of HCC. In addition, more AX-I was expressed in the tumorous portion than the nontumorous portion of HCC. AX-I was present in the hepatocytes and HCC cells, localized mainly in the cytoplasm. AX-I was expressed in poorly differentiated cancer cells. Furthermore, AX-I was tyrosine-phosphorylated in HCC. We also found that some of the AX-I- positive hepatocytes in the nontumorous tissues were derived from a particular subset of parenchymal cells (stem or oval cells). These results indicate that AX-I plays an important role in the malignant transformation process leading to HCC and that it is closely related to the histological grade of HCC. HCC would offer a novel tool with which to study the function of AX-I in malignant transformation.

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Placement of the stent above the intact sphincter of Oddi was associated with longer stent patency and lower occlusion rate.

Hepatitis E virus (HEV) genotype 3, which usually causes asymptomatic infection in Japan, induced severe hepatitis in 8 patients. To better understand genetic features of HEV associated with increased virulence, we determined the complete or near-complete nucleotide sequences of HEV from these 8 patients and from 5 swine infected with genotype 3 strain swJ19. Phylogenetic analysis showed that the isolates from the 8 patients and the 5 swine grouped separately from the other genotype 3 isolates to create a unique cluster, designated JIO. The human JIO-related viruses encoded 18 amino acids different from those of the other HEV genotype 3 strains. One substitution common to almost all human HEV strains in the JIO cluster was located in the helicase domain (V239A) and may be associated with increased virulence. A zoonotic origin of JIO-related viruses is suspected because the isolates from the 5 swine also possessed the signature V239A substitution in helicase.