AIM Fas system plays an important role in the mechanism of immune escape and counterattack of colon cancer cells. This study was to investigate the influence of anti-tumor drugs on Fas, Fas ligand expressions on colon cancer cells. METHODS MTT method was used to get the inhibition concentration 50%(IC_ 50 ) of 5-fluorouracil (5-Fu), mitomycin (MMC), cisplatin (CP) to SW480. The concentrations of anti-tumor drugs were 0, 0.5 IC_ 50 , IC_ 50 , 2 IC_ 50 , respectively. Immmunocytochemical staining and flow cytometry analysis were used to detect the expression rates of Fas and FasL on SW480 cells before and after 5-Fu, MMC, CP treatments. In situ hybridyzation was used to observe Fas, FasL mRNA in SW480 cells before and after treatments. RESULTS IC_ 50 of 5-Fu, MMC, CP to SW480 were 11.70, 3.12, 3.40 mg?L -1 , respectively. Both immmunocytochemical staining and flow cytometry analysis found that without drug treatments SW480 expressed high FasL and low Fas, after the treatment of 5-Fu, Fas expression rates on SW480 increased but FasL remained unchanged; both Fas and FasL increased after the treatment of MMC or CP. In situ hybridization showed that after the treatment of 5-Fu and Fas mRNA on SW480 increased while FasL mRNA remained unchanged; both Fas mRNA and FasL increased after the treatment of MMC or CP. CONCLUSION Anti-tumor drugs can change the expression of Fas system on SW480 cells in different ways. MMC and CP can increase the sensitivity of colon cancer cells to apoptosis signals; at the same time, they possibly facilitate immune escape of tumor cells. However, 5-Fu does not have influence on immune escape of colon cancer cells. The target point is at the level of transcription or above it.-

Purpose:To evaluate the feasibility, advantages and disadvantages of chemosensitivity test of human gastric cancer using MTT assay with short term culture tumor cells contaminated by nonmalignant cells compared with purifiedly primary culture tumor cells.Methods:Fifty nine fresh samples from patients with gastric cancer were obtained from operating rooms. Chemosensitivity results were provided by the MTT assay with short term culture cells. The primary culture cells were purified by means of a series of methods such as repeated cell attachment, differential trypsinization and natural purification which removed fibroblasts and other nonmalignant cells. The same MTT assay was conducted using purified cells. Chemosensitivity results between short term method and purification method were compared for seven antitumor drugs. Results:The success rate of short term method using the MTT assay for chemosensitivity testing was 81 4% (48 of 59 patients),and for the purification method it was 50.8(30 of 59 patients). The average was 20.2?9.5 days when primary cells were cultured into purified cancer cells. The optical density ( A ) value correlated directly with the the number of tumor cells with the two methods( P

Aim To observe the effect of 5-FU and L-Arg on the human liver carcinoma model in nude mice and study the mechanism.Methods We established the human liver carcinoma model in nude mice with BEL-7402 cell and gave normal saline,5-FU,5-FU+L-Arg by intraperitoneal injection. The tumor size was measured.The necrotic degree and range were observed by the microscope. Immunohistochemistry method and chemical colorimetry were performed to determine the expression and activity of iNOS. Nitrate reductase method was adopted to test the concentration of NO in the tumor tissue. The one-way ANOVA,Bonferroni and Kruskal-Wallis H tests were adopted for the statistical analysis.Results 5-FU combined with L-Arg promoted the tumor suppressive action apparently. The necrotic range enlarged. The expression and activity of iNOS increased. The production of NO also increased.Conclusions 5-FU combined with L-Arg has agonist effects on the inhibition of the growth of human liver carcinoma in nude mice.It may be related with inducing the synthesis of iNOS and the increase of NO.

OBJECTIVETo evaluate the effect of endogenous nitric oxide (NO) on the ability of 5-fluourouracil (5-FU) to induce apoptosis in the liver carcinoma Bel7402 cell line, and to observe the anti-tumor mechanism and effective adjuvant of 5-FU.

METHODSCells were cultured under routine conditions with Dulbecco's modified Eagle's medium (DMEM) without L-Arginine (L-Arg). We observed the expression of inducible nitric oxide synthase (iNOS) and apoptosis of cells induced by 5-FU with L-Arg added to the medium. The production of nitric oxide was determined by the cell expression of iNOS detected by immunohistochemical staining, and by the concentrations of nitrite and nitrate in the supernatant.

RESULTS5-fluourouracil significantly increased the iNOS expression to 0.1687 +/- 0.01968 (P < 0.05, vs control group), and the concentration of nitric oxide to 213 +/- 30.2 micromol/L (P < 0.05, vs control group). The apoptotic cell rate increased significantly to 17.85 +/- 0.78%, while the necrotic cell rate decreased to 3 2.99 +/- 0.83% (P < 0.05,compared with the 5-FU group). N(omega)-nitro-L-Arginine methyl ester (L-NAME), the antagonist of L-Arg, can block the apoptotic effects of endogenous nitric oxide.

CONCLUSIONS5-FU had a synergistic effects with L-Arg by increasing the production of endogenous nitric oxide. Endogenous nitric oxide plays an important role in the process where 5-FU induces apoptosis in liver carcinoma cells. L-Arg may be a good adjuvant for chemotherapy with 5-FU.

Antimetabolites, Antineoplastic ; pharmacology ; Apoptosis ; drug effects ; Arginine ; pharmacology ; Fluorouracil ; pharmacology ; Humans ; Immunohistochemistry ; Liver Neoplasms ; pathology ; Nitric Oxide ; biosynthesis ; Nitric Oxide Synthase ; analysis ; Nitric Oxide Synthase Type II ; Tumor Cells, Cultured

Antimetabolites, Antineoplastic ; pharmacology ; Apoptosis ; drug effects ; Carcinoma, Hepatocellular ; drug therapy ; pathology ; Enzyme Inhibitors ; pharmacology ; Fluorouracil ; pharmacology ; Humans ; Liver Neoplasms ; drug therapy ; pathology ; NG-Nitroarginine Methyl Ester ; pharmacology ; Nitric Oxide ; metabolism ; Nitric Oxide Synthase ; antagonists & inhibitors ; metabolism ; Nitric Oxide Synthase Type II ; Tumor Cells, Cultured ; drug effects

OBJECTIVETo document morphological changes in hepatic microcirculation in liver tissue with hepatitis B and the pathogenesis of hepatic microcirculatory disturbances.

METHODSLiver tissue samples were obtained from patients with hepatitis B by liver biopsy. These samples were examined with a light microscope and transmission electron microscope.

RESULTSHepatic microcirculatory disturbances existed in patients with hepatitis B, including those with normal liver function, manifested by red blood cell aggregation in sinusoids seen under light microscope and sinusoidal capillarization seen under electron microscope. Weibel-Palade bodies in sinusoidal endothelial cells were seen in 26 out of 53 cases. Intimate contacts were found between lymphocyte/Kupffer cells and sinusoidal endothelial cells.

CONCLUSIONSHepatic microcirculatory disturbances exist in patients with hepatitis B. The appearance of Weibel-Palade bodies in sinusoidal endothelial cells may be a key step in the development of hepatic microcirculatory disturbances.

Adolescent ; Adult ; Aged ; Female ; Hepatitis B, Chronic ; pathology ; physiopathology ; Humans ; Liver ; blood supply ; pathology ; ultrastructure ; Liver Circulation ; Male ; Microcirculation ; pathology ; ultrastructure ; Microscopy, Electron ; Middle Aged