Cyclic nucleotide-gated ion channels （CNGs） are distributed most widely in the neuronal cell. Great progress has been made in molecular mechanisms of CNG channel gating in the recent years. Results of many experimen...Cyclic nucleotide-gated ion channels （CNGs） are distributed most widely in the neuronal cell. Great progress has been made in molecular mechanisms of CNG channel gating in the recent years. Results of many experiments have indicated that the stoichiometry and assembly of CNG channels affect their property and gating. Experiments of CNG mutants and analyses of cys- teine accessibilities show that cyclic nucleotide-binding domains （CNBD） bind cyclic nucleotides and subsequently conformational changes occurred followed by the concerted or cooperative conformational change of all four subunits during CNG gating. In order to provide theoretical assistances for further investigation on CNG channels, especially regarding the disease pathogenesis of ion channels, this paper reviews the latest progress on mechanisms of CNG channels, functions of subunits, processes of subunit assembly, and conformational changes of subunit regions during gating.展开更多
AIM:The role of Helicobacter pylori (H pylori) infection in gastric acid secretion of patients with chronic gastritis remains controversial. This study was designed to elucidate the effect of H pylori on H+/K+-ATPase ...AIM:The role of Helicobacter pylori (H pylori) infection in gastric acid secretion of patients with chronic gastritis remains controversial. This study was designed to elucidate the effect of H pylori on H+/K+-ATPase activities in gastric biopsy specimens. METHODS: Eighty-two patients with chronic gastritis who had undergone upper endoscopy were included in this study. H pylori infection was confirmed by rapid urease test and histology. Gastric H+/K+-ATPase activities and serum gastrin concentrations were measured by an enzymatic method and radioimmunoassay, respectively. For those patients who received triple therapy for eradicating H pylori, changes in the activity of gastric H+/K+-ATPase and serum gastrin levels were also measured. RESULTS: The mean gastric H+/K+-ATPase activity in Hpylori-positive group (42 patients) was slightly higher than that in Hpylori-negative group (29 patients) (169.65±52.9 and 161.38±43.85nmol P/(mg·h),respectively, P=0.301). After eradication of H pylori, the gastric H+/K+-ATPase activities slightly decreased compared to prior therapy (165.03±59.50 and 158.42±38.93 nmol P/(mg·h), respectively, P=0.805). The mean basal gastrin concentration was slightly higher in H pylori-positive patients than in H pylori-negative patients (87.92±39.65 pg/mL vs75.04±42.57 pg/mL, P= 0.228). The gastrin levels fell significantly after the eradication of H pylori. (Before treatment 87.00±30.78 pg/mL, after treatment 64.73±18.96 pg/mL, P=0.015). CONCLUSION: Gastric H+/K+-ATPase activities are not associated with H pylori status in patients with chronic gastritis.展开更多
We present two schemes for preparing cluster states with atomic qubits in an ion-trap system. In the first scheme an auxiliary atomic level is needed. While in the second scheme an additional classical driven field is...We present two schemes for preparing cluster states with atomic qubits in an ion-trap system. In the first scheme an auxiliary atomic level is needed. While in the second scheme an additional classical driven field is used, and the multi-ion cluster states can be generated by one step. Both the schemes are insensitive to thermal motion of the ions, all the facilities used in them are well within state of the art.展开更多
基金This work was supported by the Provincial Key Projects for Scientifical and Technological Research of Zhejiang Province (No. 2006C12058)National Natural Science Foundation of China (No. 30571335) and a Grant-in-Aid for Innovative Training of Doctoral Students in JIangsu Province,China.
文摘Cyclic nucleotide-gated ion channels （CNGs） are distributed most widely in the neuronal cell. Great progress has been made in molecular mechanisms of CNG channel gating in the recent years. Results of many experiments have indicated that the stoichiometry and assembly of CNG channels affect their property and gating. Experiments of CNG mutants and analyses of cys- teine accessibilities show that cyclic nucleotide-binding domains （CNBD） bind cyclic nucleotides and subsequently conformational changes occurred followed by the concerted or cooperative conformational change of all four subunits during CNG gating. In order to provide theoretical assistances for further investigation on CNG channels, especially regarding the disease pathogenesis of ion channels, this paper reviews the latest progress on mechanisms of CNG channels, functions of subunits, processes of subunit assembly, and conformational changes of subunit regions during gating.
基金Supported by the Ratchadapisek Sompotch Fund, Faculty of Medicine, Chulalongkom University, Thailand
文摘AIM:The role of Helicobacter pylori (H pylori) infection in gastric acid secretion of patients with chronic gastritis remains controversial. This study was designed to elucidate the effect of H pylori on H+/K+-ATPase activities in gastric biopsy specimens. METHODS: Eighty-two patients with chronic gastritis who had undergone upper endoscopy were included in this study. H pylori infection was confirmed by rapid urease test and histology. Gastric H+/K+-ATPase activities and serum gastrin concentrations were measured by an enzymatic method and radioimmunoassay, respectively. For those patients who received triple therapy for eradicating H pylori, changes in the activity of gastric H+/K+-ATPase and serum gastrin levels were also measured. RESULTS: The mean gastric H+/K+-ATPase activity in Hpylori-positive group (42 patients) was slightly higher than that in Hpylori-negative group (29 patients) (169.65±52.9 and 161.38±43.85nmol P/(mg·h),respectively, P=0.301). After eradication of H pylori, the gastric H+/K+-ATPase activities slightly decreased compared to prior therapy (165.03±59.50 and 158.42±38.93 nmol P/(mg·h), respectively, P=0.805). The mean basal gastrin concentration was slightly higher in H pylori-positive patients than in H pylori-negative patients (87.92±39.65 pg/mL vs75.04±42.57 pg/mL, P= 0.228). The gastrin levels fell significantly after the eradication of H pylori. (Before treatment 87.00±30.78 pg/mL, after treatment 64.73±18.96 pg/mL, P=0.015). CONCLUSION: Gastric H+/K+-ATPase activities are not associated with H pylori status in patients with chronic gastritis.
基金The project supported by the Scientific Research Fund of the Education Department of Hunan Province under Grant No.06C354the Natural Science Foundation of Hunan Province under Grant No.06JJ5015
文摘We present two schemes for preparing cluster states with atomic qubits in an ion-trap system. In the first scheme an auxiliary atomic level is needed. While in the second scheme an additional classical driven field is used, and the multi-ion cluster states can be generated by one step. Both the schemes are insensitive to thermal motion of the ions, all the facilities used in them are well within state of the art.
