AIM： To determine the effect of melatonin pre- and post-treatment on the severity of L-arginine （L-Arg） -induced experimental pancreatitis in rats. METHODS： Male Wistar rats （25） were divided into five groups. T...AIM： To determine the effect of melatonin pre- and post-treatment on the severity of L-arginine （L-Arg） -induced experimental pancreatitis in rats. METHODS： Male Wistar rats （25） were divided into five groups. Those in group A received two injections of 3.2 g/kg body weight L-Arg i.p. at an interval of 1 h. In group MA, the rats were treated with 50 mg/kg body weight melatonin i.p. 30 min prior to L-Arg administration. In group AM, the rats received the same dose of melatonin 1 h after L-Arg was given. In group M, a single dose of melatonin was administered as described previously. In group C the control animals received physiological saline injections i.p. All rats were exsanguinated 24 h after the second L-Arg injection. RESULTS： L-Arg administration caused severe necrotizing pancreatitis confirmed by the significant elevations in the serum amylase level, the pancreatic weight/body weight ratio （pw/bw）, the pancreatic IL-6 content and the myeloperoxidase activity, relative to the control values. Elevation of the serum amylase level was significantly reduced in rats given melatonin following L-Arg compared to rats injected with L-Arg only. The activities of the pancreatic antioxidant enzymes （Cu/Zn-superoxide dismutase （CulZn-SOD） and catalase （CAT）） were significantly increased 24 h after pancreatitis induction. Melatonin given in advance of L-Arg significantly reduced the pancreatic CAT activity relative to that in the rats treated with L-Arg alone. In the liver, L-Arg significantly increased the lipid peroxidation level, and the glutathione peroxidase and Cu/Zn-SOD activities, whereas the Mn-SOD activity was reduced as compared to the control rats. Melatonin pre-treatment prevented these changes. CONCLUSION： Melatonin is an antioxidant that is able to counteract some of the L-Arg-induced changes during acute pancreatitis, and may therefore be helpful in the supportive therapy of patients with acute necrotizing pancreatitis.展开更多
In the present study, the involvement of L-arginine(L-Arg) NO on the protective action of electroacupuncture(EA) on cerebral ischemic injury was observed in acute ischemia-reperfusion(IR) rat model by taking regional ...In the present study, the involvement of L-arginine(L-Arg) NO on the protective action of electroacupuncture(EA) on cerebral ischemic injury was observed in acute ischemia-reperfusion(IR) rat model by taking regional cerebral blood flow(r-CBF),cerebral water content(CWC),and blood nitric oxide(NO) contents as indexes. Results showed that 1) EA could cause r-CBF and serum NO content to increase and CWC to lower, suggesting an protective action of EA on IR cerebral injury; 2) intravenous injection of L-Arg also had an protective effect on cerebral IR cerebral injury, while L-NNA had no this effect; and 3) pre-treatment with L-Arg might strengthen the effect of EA further, while pretreatment with L-NNA could weaken its effect. It indicates that L-Arg-NO may be involved in the effect of EA in protecting the brain from ischemic injury.展开更多
The purpose of the given work was the experimental analysis of features of Arg-X proteolysis in proteom of supramolecular structures of bacterial cells during their life cycle. The basic attention was devoted to relax...The purpose of the given work was the experimental analysis of features of Arg-X proteolysis in proteom of supramolecular structures of bacterial cells during their life cycle. The basic attention was devoted to relaxation of Arg-X sites of proteom in association with the evolutionary significance ofArg-rich histones in the eukaryotic kingdom. These properties were not studied in the prokaryotes. Cells ofE. coli were grown to the stationary phase, collected by centrifugation and washed. All cells were taken over from 50 min to 430 min at intervals of 20 min and were preserved in glycerol. The supramolecular structures were fractionated from bacterial cells by increasing ionic strength of solution. The Arg-Xactivity was assessed by cleavage of Arg-Xbonds in the arginine-enriched protein protamine in all cell fractions. We have shown that during the stationary phase in the life cycle of E. coli, there are a high continuous activity of the Arg-X processing at the level of＂cytoskeleton＂ of the cell and bright cyclic activity in the cytoplasm.展开更多
基金Supported by the Hungarian Scientific Research Fund (T042589).
文摘AIM： To determine the effect of melatonin pre- and post-treatment on the severity of L-arginine （L-Arg） -induced experimental pancreatitis in rats. METHODS： Male Wistar rats （25） were divided into five groups. Those in group A received two injections of 3.2 g/kg body weight L-Arg i.p. at an interval of 1 h. In group MA, the rats were treated with 50 mg/kg body weight melatonin i.p. 30 min prior to L-Arg administration. In group AM, the rats received the same dose of melatonin 1 h after L-Arg was given. In group M, a single dose of melatonin was administered as described previously. In group C the control animals received physiological saline injections i.p. All rats were exsanguinated 24 h after the second L-Arg injection. RESULTS： L-Arg administration caused severe necrotizing pancreatitis confirmed by the significant elevations in the serum amylase level, the pancreatic weight/body weight ratio （pw/bw）, the pancreatic IL-6 content and the myeloperoxidase activity, relative to the control values. Elevation of the serum amylase level was significantly reduced in rats given melatonin following L-Arg compared to rats injected with L-Arg only. The activities of the pancreatic antioxidant enzymes （Cu/Zn-superoxide dismutase （CulZn-SOD） and catalase （CAT）） were significantly increased 24 h after pancreatitis induction. Melatonin given in advance of L-Arg significantly reduced the pancreatic CAT activity relative to that in the rats treated with L-Arg alone. In the liver, L-Arg significantly increased the lipid peroxidation level, and the glutathione peroxidase and Cu/Zn-SOD activities, whereas the Mn-SOD activity was reduced as compared to the control rats. Melatonin pre-treatment prevented these changes. CONCLUSION： Melatonin is an antioxidant that is able to counteract some of the L-Arg-induced changes during acute pancreatitis, and may therefore be helpful in the supportive therapy of patients with acute necrotizing pancreatitis.
文摘In the present study, the involvement of L-arginine(L-Arg) NO on the protective action of electroacupuncture(EA) on cerebral ischemic injury was observed in acute ischemia-reperfusion(IR) rat model by taking regional cerebral blood flow(r-CBF),cerebral water content(CWC),and blood nitric oxide(NO) contents as indexes. Results showed that 1) EA could cause r-CBF and serum NO content to increase and CWC to lower, suggesting an protective action of EA on IR cerebral injury; 2) intravenous injection of L-Arg also had an protective effect on cerebral IR cerebral injury, while L-NNA had no this effect; and 3) pre-treatment with L-Arg might strengthen the effect of EA further, while pretreatment with L-NNA could weaken its effect. It indicates that L-Arg-NO may be involved in the effect of EA in protecting the brain from ischemic injury.
文摘The purpose of the given work was the experimental analysis of features of Arg-X proteolysis in proteom of supramolecular structures of bacterial cells during their life cycle. The basic attention was devoted to relaxation of Arg-X sites of proteom in association with the evolutionary significance ofArg-rich histones in the eukaryotic kingdom. These properties were not studied in the prokaryotes. Cells ofE. coli were grown to the stationary phase, collected by centrifugation and washed. All cells were taken over from 50 min to 430 min at intervals of 20 min and were preserved in glycerol. The supramolecular structures were fractionated from bacterial cells by increasing ionic strength of solution. The Arg-Xactivity was assessed by cleavage of Arg-Xbonds in the arginine-enriched protein protamine in all cell fractions. We have shown that during the stationary phase in the life cycle of E. coli, there are a high continuous activity of the Arg-X processing at the level of＂cytoskeleton＂ of the cell and bright cyclic activity in the cytoplasm.
