Effect of 5-fluorouracil on cell cycle regulatory proteins in human colon cancer cell line.

We investigated the effects of 5-fluorouracil (5-FU) on cell cycle-regulating proteins in RPMI 4788 cells. 5-FU inhibited cell growth dose-dependently and this growth inhibition was accompanied with cell cycle accumulation in early S phase and increased expression of cyclin A. When cells were released from short-term treatment (3 or 24 h) with 5-FU, the cell cycle started to progress again and cyclin A protein levels decreased. Cyclin A-associated kinase activity assay showed that cyclin A-cyclin-dependent kinase (Cdk) 2 kinase activity was altered by 5-FU treatment concomitantly with the changes in cell cycle state seen in flow cytometric analysis. Furthermore, the elevation of cyclin A protein level by 5-FU treatment was observed in three other human cancer cell lines, DLD-1, H226Br and T.Tn. These results suggest that cyclin A protein levels in cancer cells are increased by 5-FU, and the cyclin A function and degradation mechanism remain normal.

Cyclin A and Cdk2 kinase activity are suppressed by combined treatment with tumor necrosis factor-alpha and interferon-alpha.

We previously reported that combined treatment with tumor necrosis factor-alpha (TNF-alpha) and interferon-alpha (IFN-alpha) showed a synergistic antitumor effect via regulation of cell cycle progression in the S phase. Here, we investigated the effect of the combined treatment with TNF-alpha and IFN-alpha on cell cycle regulating protein in RPMI 4788 cells. Treatment with TNF-alpha or IFN-alpha alone showed no effect on these proteins, however, the combined treatment showed suppression of cyclin A protein and its associated kinase activity. Furthermore, although the combined treatment inhibited Cdk2 kinase activity, the amount of Cdk2 protein was not affected. These results suggested that TNF-alpha and IFN-alpha work together to suppress cyclin A and Cdk2 kinase activity and to inhibit cell cycle progression in the S phase.

[Immunohistochemical study of growth factors and oncogenes in gastric carcinomas].

Immunohistochemical staining for EGF, EGFR, c-erbB-2, p53, K-ras and PCNA was performed on the formalin-fixed, paraffin embedded sections of resected gastric carcinomas. A relatively high positive rate was observed for EGFR and c-erbB-2 in the well-differentiated adenocarcinomas and p53 in the poorly-differentiated adenocarcinomas. The positive rate of these factor was higher in the advanced cases than in the early cases, and also in the deep invasive area than the superficial area. According to the PCNA staining, a relatively high positive rate was observed in the well-differentiated adenocarcinomas compared with the early cases of poorly-differentiated adenocarcinomas, but the positive rate was markedly higher in the advanced cases of the latter. Typical signet-ring cell carcinomas showed the lowest positivity rate compared with the other histological types of gastric carcinomas.

[Immunohistochemical study of the lymph-follicles and lymphocytes in the gastric mucosa].

Immunohistochemical stainings according to ABC method (UCHL-1,L-26,MT-1,MB-1,IgG,IgA,IgD,IgM, kappa, lambda, LN-1 and LN-2) for the lymphocytes in the germinal center, mantle zone and infiltrative lymphocytes in the gastric mucosa of 30 cases of chronic gastritis and 10 cases of reactive lymphoreticular hyperplasia (RLH) were performed. Lymphocytes in the germinal center and mantle zone consisted usually of B-cells positively stained by L-26 and MB-1. However, in the interstitially infiltrative cells,T-cells positively stained by UCHL-1 and MT-1 were not infrequently contained. Immunoglobulin stainings revealed marked positivity for IgG,IgA,IgD,IgM, kappa and lambda in the interstitial lymphocytes and plasma cells. As to the RLH, small number of T-cells scattered in the germinal center and surrounding area of lymph follicles, and large number of T-cells were found among the follicles, where B-cells were more infrequently found than in the interstitial area of propria mucosae. Confusion of enlarged germinal centers and monotonous proliferation of lymphocytes among the lymph follicles showing monotonous positivity for the stains of heavy and light chains in the cases of RLH were suggestive of malignant change.

[Reoperation cases long after Rastelli operation: right ventricular outflow tract reconstruction by means of a xenograft non-valved patch].

Two cases who underwent the new procedure of treatment for extracardiac conduit stenosis after Rastelli operation are reported. They had undergone Rastelli operation 11 and 12 years ago. Because of stenotic Hancock valve of the conduit, they were reoperated. A longitudinal incision was made anteriorly over the conduit and the conduit was dissected free. The sides and posterior half of the conduit bed were preserved. The roof of the new right ventricular outflow tract was formed using a xenograft pericardium patch. Their postoperative courses were smooth.