Yukinori Yoshida

Intrahepatic transplantation of normal hepatocytes prevents Wilson's disease in Long-Evans cinnamon rats

BACKGROUND & AIMS Long-Evans cinnamon (LEC) rats are an animal model of Wilsons disease. This study investigated whether intrahepatic transplantation of normal hepatocytes can prevent Wilsons disease in LEC rats. METHODS Hepatocytes of newborn Long-Evans agouti (LEA) rats were transplanted into the livers of LEC rats before onset of hepatic disease. Expression of normal transcripts from the gene linked to Wilsons disease was investigated at 30 weeks of age by reverse-transcription polymerase chain reaction and in situ hybridization. RESULTS Eight of 16 (50.0%) untreated LEC rats died of hepatic failure during 20-30 weeks of age. Of the 27 LEC rats with transplanted cells, 2 (7.4%) died of hepatic failure and 4 died of ileus complicated by the surgical treatment. In the recipient livers, the transplanted cells comprised 4%-20% of the hepatocyte populations, expressing normal messenger RNA transcribed from the Wilsons disease gene, and hepatic copper deposition was reduced to approximately 60% of that in untreated LEC rats. CONCLUSIONS Transplantation of normal hepatocytes prevents Wilsons disease in LEC rats.

Flow cytometric and functional analysis of mononuclear cells infiltrating the liver in experimental autoimmune hepatitis

Experimental autoimmune hepatitis was produced by immunizing Wistar rats with syngeneic liver proteins. Mononuclear cells infiltrating the liver tissue were identified by immunohistochemical techniques using monoclonal antibodies specific for subpopulations of rat lymphocytes. The strong infiltration of CD8+ cytotoxic T lymphocytes (CTL) were found in the portal areas. Subpopulations of mononuclear cells infiltrating the liver, spleen cells and peripheral blood lymphocytes were identified by flow cytometry. Flow cytometric analysis revealed the presence of CD5‐ and CD8+ lymphocytes in the liver tissues. Mononuclear cells infiltrating the liver were isolated from Wistar rats having autoimmune hepatitis to determine whether those exhibit cytotoxicity against syngeneic hepatocytes; they exhibited cytotoxicity against isolated syngeneic hepatocytes, but failed to lyse K562 cells, syngeneic concanavalin A‐activated splenocytes and allogeneic hepatocytes. Depietion of CD8+ T cells significantly reduced the cytotoxic ability of mononuclear cells infiltrating into the liver against syngeneic hepatocytes. These findings support the idea that liver cell injury in experimental autoimmune hepatitis may at least in part be mediated by CTL.

Hemangiopericytoma of the Sigmoid Mesentery: Report of a Case with Immunohistochemical Findings

Hemangiopericytoma has been described in various sites in the body but only rarely in the mesocolon. This report describes the clinical course of an 83-year-old man whose mesosigmoidal tumor (hemangiopericytoma) was resected on 11 November 1994. Immunostaining was done with the following primary antibodies: α-actin, vimentin, factor VIII-related antigen, chromogranin, and S-100. Staining for factor VIII-related antigen was strongly positive in the endothelial cells of the capillaries, but negative in the tumor cells. The tumor cells contained immunoreactive vimentin, but demonstrated no α-actin, chromogranin, or S-100. Since the operation, the patient has been disease-free for 11 months.

Resistance of primary cultured mouse hepatic tumor cells to cellular senescence despite expression of p16Ink4a, p19Arf, p53, and p21Waf1/Cip1

Primary cultured mouse hepatic cells become senescent within a short period, although rare cells form colonies from which continuously proliferating cell lines can be established. In contrast, hepatic tumor (HT) cells show little senescence and higher colony‐forming capacity. To assess this difference, we investigated p16Ink4a/p19Arf/p53/p21Waf1/Cip1 expression in primary normal and HT cells, together with cell lines established from both. In primary normal cells, p16Ink4a/p19Arf were expressed only in association with senescence and disappeared at later stages of colony formation. In contrast, primary HT cells showed sustained p16Ink4a/p19Arf expression from the beginning. No p16Ink4a/p19Arf alterations, such as deletion, mutations, or hypermethylation, were detected in the primary HT cells, although most cell lines derived from either normal or HT cell colonies lost p16Ink4a or p19Arf expression owing to hypermethylation or homozygous deletion of p16Ink4a/p19Arf. On the other hand, primary normal and HT cells and most cell lines showed constitutively elevated expression of p53/p21Waf1/Cip1, with a further increment after ultraviolet ir‐radiation, indicating a functionally normal p53 pathway. These results indicate that primary HT cells are resistant to senescence despite retaining p16Ink4a/p19Arf/p53/p21Waf1/Cip1 expression and that loss of p16Ink4a/p19Arf function is associated only with establishment of the cell lines.

Analysis of mononuclear cells infiltrating tumor in solitary hepatoma model

Abstract Ten million syngeneic hepatocellular carcinoma (FAA-HTCI) cells injected into liver are sufficient to kill Fischer rats within 2 months. Fischer rats became resistant to FAA-HTCI cells by repeated sensitization with MMC-treated FAA-HTC1 cells. Histopathological studies revealed massive accumulation of mononuclear cells in tumor tissues of sensitized rats that were rejecting syngeneic FAA-HTCI cells, whereas very few mononuclear cells were found in tumor tissues of control rats. Cell populations infiltrating the tumor tissues were identified by immunohistochemical techniques and flow cytometric analysis. Mononuclear cells found within the regressing tumors of the sensitized rats were mostly identified as being T cells, and two-thirds of these T cells were CD8 positive. Compared to control rats, killer activity of mononuclear cells infiltrating tumor tissues was significantly increased in the sensitized rats. Depletion of CD8(+) T cells significantly reduced the cytotoxic ability of mononuclear cells infiltrating tumors obtained from sensitized rats. In contrast, depletion of CD 16(+) cells significantly reduced the cytotoxic ability of mononuclear cells infiltrating tumors obtained from control rats.

Molecular form of IgM antibody to hepatitis B core antigen in sera from the patients with chronic hepatitis B virus infection.

IgM型HBc抗体の分子性状を,B型肝炎ウイルスの一過性感染と持続感染で比較するとともに,持続感染において,その抗体価の変動に伴う分子性状の変化を検討した.その結果,一過性感染では急性期・回復期ともにその抗体活性は19S IgMのみに認められた.それに対し,持続感染では19S IgMばかりでなく7S IgMも抗体活性が認められた.さらに,持続感染ではIgM型HBc抗体が陰性時には7S IgMが主体であるが,急性増悪時など抗体陽性になる時にほ19S IgMが主体となっており,この様な分子性状の変化は同一症例でも確認された.つまり,持続感染例では急性肝炎と異なり7S IgMもIgM型HBc抗体活性を示すが,その急性増悪に際しては,19S成分のIgM型HBc抗体が増加すると考えられた.