Diallyl disulfide selectively causes checkpoint kinase-1 mediated G2/M arrest in human MGC803 gastric cancer cell line.

Previous studies have shown that diallyl disulfide (DADS), a naturally occurring anticancer agent in garlic, arrested human gastric cancer cells (MGC803) in the G2/M phase of the cell cycle. Due to the importance of cell cycle redistribution in DADS-mediated anticarcinogenic effects, we investigated the role of checkpoint kinases (Chk1 and Chk2) during DADS-induced cell cycle arrest. In the present study, the northern blot analysis showed that mRNA expression of for Chkl and Chk2 was unchanged. Notably, DADS induced the accumulation of phosphorylated Chk1, but not of Chk2, activated phospho-ATR (ATM-RAD3-related gene), and dowregulated CDC25C and cyclin B1 expression. Furthermore, CDC25C was immunoprecipitated by anti-Chk1 but not anti-Chk2. Results of the overexpression and knockdown studies, showed that Chk1 but not Chk2 regulated the DADS-induced G2/M arrest of MGC803 cells. The overexpression of Chk1 resulted in significantly increased DADS-induced G2/M arrest, increased DADS-induced Chk1 phosphorylation and inhibited CDC25C expression. Knockdown of Chk1 reduced DADS­induced G2/M arrest and blocked the DADS-induced inhibition of CDC25C and cyclin B1 expression. These results suggested that Chk1 is important in DADS­induced cell cycle G2/M arrest in the human MGC803 gastric cancer cell line. Furthermore, the DADS-induced G2/M checkpoint response is mediated by Chk1 signaling through ATR/Chk1/CDC25C/cyclin B1.

Feasibility and safety of magnetic-controlled capsule endoscopy system in examination of human stomach: a pilot study in healthy volunteers.

OBJECTIVE: To assess the feasibility and safety of magnetic-controlled capsule endoscopy (MCE) system for examination of human stomach. METHODS: This pilot study enrolled 34 healthy volunteers. All subjects swallowed the MCE and gas-producing powder for gastric distention. An external robot was used to generate magnetic field to manipulate MCE inside the stomach. The primary measurements included safety, gastric preparation, maneuverability and visualization of gastric mucosa. RESULTS: Gastric preparation and examination was well accepted by subjects and there were no adverse events. The examination in the stomach takes 43.8±10.0min (27-60). The cleanliness was evaluated as good in the 30 (88.2%) subjects and as moderate in 4 (11.8%) subjects. The distention of gastric cavity was evaluated as good in the 29 (85.3%) subjects and moderate in 5 (14.7%) subjects. Maneuverability of the MCE to movements of the guidance magnet robot was graded as good in 29 (85.3%) subjects and moderate in 5 (14.7%) subjects. More than 75% gastric mucosa was visualized in 27 (79.4%) subjects and 50% to 75% in 7 (20.6%) subjects. Visualization of the gastric cardia, fundus, body, angulus, antrum and pylorus was subjectively assessed as complete in 82.4%, 85.3%, 100.0%, 100.0%, 100.0% and 100.0%, respectively. Polyp and erosive lesions were found in 7 subjects. CONCLUSION: Magnetic-controlled capsule endoscopy used for examination of the human stomach is feasible and safe.

Effects of selenium on the antioxidant enzymes response of Neocaridina heteropoda exposed to ambient nitrite.

The effects of dietary Selenium (Se) supplementation on muscle superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPX) activities and haemolymph superoxide anions (O(2)-) of Neocaridina heteropoda exposed to ambient nitrite were investigated. The results showed supplementation of Se in diet could enhance the resistance of shrimp to low concentration ambient nitrite. The results demonstrated that Se might have a potentially useful role as an effective antioxidant and resistance to aqueous nitrite in shrimp and the effect of the organic Se was better than that of the inorganic Se.