Many cytokines, in particular tumor necrosis factor (TNF)-a have been known to play an important role in the pathogenesis of gastric mucosal lesions caused by various factors such as drugs and Helicobacter pylori infection. Our previous studies have shown that the polysaccharide fractions isolated from the fruiting bodies of Ganoderma lucidum (GLPS) prevented indomethacin- and acetic acid-induced gastric mucosal lesions in the rat. However, the mechanisms remain unclear. This study aimed to investigate whether GLPS had a direct mucosal healing effect in the indomethacin-treated rat, and to explore the possible mechanisms by determining the gastric mucosal mRNA and protein levels of TNF-a and ornithine decarboxylase (ODC) activity. In addition, the effects of GLPS on the cellular proliferation, ODC and c-Myc protein expression and mucus synthesis in the rat gastric cell culture (RGM-1) were examined. The present study demonstrated that GLPS at 250 and 500mg/kg by intragastric input caused ulcer-healing effect in the rat; this was accompanied with a significant suppression of TNF-a gene expression, but with an increased ODC activity. In RGM-1 cells, GLPS at 0.05, 0.25 and 1.0mg/ml significantly enhanced [3H]thymidine incorporation and ODC activity in a concentration-dependent manner. However, these effects were abrogated by the addition of the ODC inhibitor, DL-a-difluoromethyl-ornithine (DFMO). GLPS at 0.25-1.0mg/ml also increased mucus synthesis, as indicated by the increased D-[6-3H]glucosamine incorporation in RGM-1

Micromolar concentrations of estradiol are required to inhibit the oxidation of low-density lipoproteins (LDL) in vitro. Recent evidence suggests that estradiol must be modified before it can become an effective antioxidant at physiological levels. Our aim was to determine other possible conditions under which low concentrations of 17b-estradiol can reduce LDL oxidation. LDL susceptibility to oxidation was monitored by measurements of conjugated diene formation. High levels of 17b-estradiol reduced oxidative modification of LDL. Vitamin C and vitamin E also increased LDL resistance to Cu21-mediated oxidation. More importantly, 10 nM 17b-estradiol, which on its own had no effect, exhibited significant antioxidant actions in the presence of either vitamins C or E. In conclusion, supraphysiological concentrations of 17b-estradiol are required to exert antioxidant effects directly in vitro. However, in the presence of vitamins C and E, concentrations of 17b-estradiol close to physiological levels can also protect LDL from oxidation.

Purpose. The multidrug resistance associated protein (MRP) 4 is a member of the adenosine riphosphate (ATP)-binding cassette transporter family. Camptothecins (CPTs) have shown substantial anticancer activity against a broad spectrum of tumors by inhibiting DNA topoisomerase I, but tumor resistance is one of the major reasons for therapeutic failure. Pglycoprotein, breast cancer resistance protein, MRP1, and MRP2 have been implicated in resistance to various CPTs including CPT-11 (irinotecan), SN-38 (the active metabolite of CPT-11), and topotecan. In this study, we explored the resistance profiles and intracellular accumulation of a panel of CPTs including CPT, CPT-11, SN-38, rubitecan, and 10-hydroxy-CPT (10-OH-CPT) in HepG2 cells with stably overexpressed human MRP4. Other anticancer agents such as paclitaxel, cyclophosphamide, and carboplatin were also included. Methods. HepG2 cells were transfected with an empty vehicle plasmid (V/HepG2) or human MRP4 (MRP4/HepG2). The resistance profiles of test drugs in exponentially growing V/HepG2 and MRP4/HepG2 cells were examined using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazonium bromide (MTT) assay with 4 or 48 h exposure time of the test drug in the absence or presence of various MRP4 inhibitors. The accumulation of CPT-11, SN-38, and paclitaxel by V/HepG2 and MRP4/HepG2 cells was determined by validated high-performance liquid chromatography methods. Results. Based on the resistance folds from the MTT assay with 48 h exposure time of the test drug, MRP4 conferred resistance to CPTs tested in the order 10-OH-CPT (14.21) >SN-38 carboxylate (9.70) >rubitecan (9.06) >SN-38 lactone (8.91) >CPT lactone (7.33) >CPT-11 lactone (5.64) >CPT carboxylate (4.30) >CPT-11 carboxylate (2.68). Overall, overexpression of MRP4 increased the IC50 values 1.78-to 14.21-fold for various CPTs in lactone or carboxylate form. The resistance of MRP4 to various CPTs tested was significantly reversed in the presence of DL-buthionine-(S,R)-sulfoximine (BSO, a gglutamylcysteine synthetase inhibitor), MK571, celecoxib, or diclofenac (all MRP4 inhibitors). In addition, the accumulation of CPT-11 and SN-38 over 120 min in MRP4/HepG2 cells was significantly reduced compared to V/HepG2 cells, whereas the addition of celecoxib, MK571, or BSO significantly increased their accumulation in MRP4/HepG2 cells. There was no significant difference in the intracellular accumulation of paclitaxel in V/HepG2 and MRP4/HepG2 cells, indicating that Pglycoprotein was not involved in the observed resistance to CPTs in this study. MRP4 also conferred resistance to cyclophosphamide and this was partially reversed by BSO. However, MRP4 did not increase resistance to paclitaxel, carboplatin, etoposide (VP-16), 5-fluorouracil, and cyclosporine. Conclusions. Human MRP4 rendered significant resistance to cyclophosphamide, CPT, CPT-11, SN-38, rubitecan, and 10-OH-CPT. CPT-11 and SN-38 are substrates for MRP4. Further studies are needed to explore the role of MRP4 in resistance, toxicity, and pharmacokinetics of CPTs and cyclophosphamide.

Objective: This study was to investigate the gene mutation of thiopurine S-methyltransferase (TPMT) in Uygur Chinese. Methods: Polymerase chain reaction-based methods were used to analyze three commonly reported inactivating mutations-G238C, G460A and A719G. Results: One TPMT*3A heterozygote and five TPMT*3C heterozygotes were found in 160 Uygur Chinese subjects, and allele frequencies of TPMT*3A and TPMT*3C were 0.3% and 1.6%, respectively. Conclusion: TPMT*3C is a common mutant allele in Uygur Chinese, while TPMT*3A is a rare mutant allele in Uygur Chinese.