AIM:To establish a rat ethanol gastritis model,we evaluated the effects of ethanol on gastric mucosa and studied the preventive effects of geranylgeranylacetone on ethanol-induced chronic gastritis.METHODS:One hundred...AIM:To establish a rat ethanol gastritis model,we evaluated the effects of ethanol on gastric mucosa and studied the preventive effects of geranylgeranylacetone on ethanol-induced chronic gastritis.METHODS:One hundred male Sprague-Dawley rats were randomly divided into 4 equal groups:normal control group,undergoing gastric perfusion of normal saline(NS) by gastrogavage;model control group and 2 model therapy groups that underwent gastric perfusion with ethanol(distillate spirits with 56% ethanol content) by gastrogavage for 4 wk.Low or high doses of geranylgeranylacetone were added 1 h before ethanol perfusion in the 2 model therapy groups,while the same amount of NS,instead of geranylgeranylacetone was used in that model control group.The rats were then sacrificed and stomachs were removed.The injury level of the gastric mucosa was observed by light and electron microscopy,and the levels of prostaglandin 2(PGE 2),endothelin-1(ET-1) and nitric oxide(NO) were measured by radioimmunoassay and the Griess method.RESULTS:The gastric mucosal epidermal damage score(EDS;4.5) and ulcer index(UI;12.0) of the model control group were significantly higher than that of the normal control group(0 and 0 respectively,all P = 0.000).The gastric mucosal EDS and UI of the 2 model therapy groups(EDS:2.5 and 2.0;UI:3.5 and 3.0) were significantly lower than that of the model control group(all P < 0.01).There was no statistically significant difference between the low-dose and high-dose model therapy groups.The expression value of plasma ET-1 of the model control group was higher than that of the normal control group(P < 0.01) and the 2 model therapy groups(all P < 0.01).The expression values of gastric mucosal PGE 2 and serum NO of the model control group were lower than those of the normal control group(all P < 0.05) and the 2 model therapy groups(all P < 0.05).The thickness of the gastric mucous layerand the hexosamine content in the model control group were significantly lower than that in the normal control group(all P < 0.01) and the 2 model therapy groups(all P < 0.05).Scanning and transmission electron microscopy observation showed that in the model control group,the epithelial junctions were vague,the intercellular joints disappeared and damage of the intracellular organelles were significantly worse than those in the normal control group.However,in the 2 model therapy groups,damage to the intercellular joints and organelles was ameliorate relative to the model control group.CONCLUSION:Administration of geranylgeranylacetone was correlated with a more favorable pattern of gastric mucosa damage after ethanol perfusion.The mechanism could be related to regulation of ET-1,NO and PGE 2.展开更多
Motivation of this work has its origin in the boundary layer control for aeronautics and turbomachinery. For thatpurpose boundary layer can be modified by perforated plates with holes of specific sizes. The questions ...Motivation of this work has its origin in the boundary layer control for aeronautics and turbomachinery. For thatpurpose boundary layer can be modified by perforated plates with holes of specific sizes. The questions whichrise in such configuration are related to the existence of optimal size of the holes and the influence of microscalephenomena on the global flow patterns. This paper concentrates on the issue of the entrance effects on the microchannelflow. It is shown that mass flow rate is only insignificantly influenced by slip effects. Global parameterssuch as pressure difference and geometrical shape in more pronounced way alter flow behavior. In this paper weconcentrate on the numerical investigation of the microchannel flow for Kn < 0.01 and Re < 500. The channellength is finite. Hence, entrance and outlet effects on microchannel flow can be studied.展开更多
文摘AIM:To establish a rat ethanol gastritis model,we evaluated the effects of ethanol on gastric mucosa and studied the preventive effects of geranylgeranylacetone on ethanol-induced chronic gastritis.METHODS:One hundred male Sprague-Dawley rats were randomly divided into 4 equal groups:normal control group,undergoing gastric perfusion of normal saline(NS) by gastrogavage;model control group and 2 model therapy groups that underwent gastric perfusion with ethanol(distillate spirits with 56% ethanol content) by gastrogavage for 4 wk.Low or high doses of geranylgeranylacetone were added 1 h before ethanol perfusion in the 2 model therapy groups,while the same amount of NS,instead of geranylgeranylacetone was used in that model control group.The rats were then sacrificed and stomachs were removed.The injury level of the gastric mucosa was observed by light and electron microscopy,and the levels of prostaglandin 2(PGE 2),endothelin-1(ET-1) and nitric oxide(NO) were measured by radioimmunoassay and the Griess method.RESULTS:The gastric mucosal epidermal damage score(EDS;4.5) and ulcer index(UI;12.0) of the model control group were significantly higher than that of the normal control group(0 and 0 respectively,all P = 0.000).The gastric mucosal EDS and UI of the 2 model therapy groups(EDS:2.5 and 2.0;UI:3.5 and 3.0) were significantly lower than that of the model control group(all P < 0.01).There was no statistically significant difference between the low-dose and high-dose model therapy groups.The expression value of plasma ET-1 of the model control group was higher than that of the normal control group(P < 0.01) and the 2 model therapy groups(all P < 0.01).The expression values of gastric mucosal PGE 2 and serum NO of the model control group were lower than those of the normal control group(all P < 0.05) and the 2 model therapy groups(all P < 0.05).The thickness of the gastric mucous layerand the hexosamine content in the model control group were significantly lower than that in the normal control group(all P < 0.01) and the 2 model therapy groups(all P < 0.05).Scanning and transmission electron microscopy observation showed that in the model control group,the epithelial junctions were vague,the intercellular joints disappeared and damage of the intracellular organelles were significantly worse than those in the normal control group.However,in the 2 model therapy groups,damage to the intercellular joints and organelles was ameliorate relative to the model control group.CONCLUSION:Administration of geranylgeranylacetone was correlated with a more favorable pattern of gastric mucosa damage after ethanol perfusion.The mechanism could be related to regulation of ET-1,NO and PGE 2.
文摘Motivation of this work has its origin in the boundary layer control for aeronautics and turbomachinery. For thatpurpose boundary layer can be modified by perforated plates with holes of specific sizes. The questions whichrise in such configuration are related to the existence of optimal size of the holes and the influence of microscalephenomena on the global flow patterns. This paper concentrates on the issue of the entrance effects on the microchannelflow. It is shown that mass flow rate is only insignificantly influenced by slip effects. Global parameterssuch as pressure difference and geometrical shape in more pronounced way alter flow behavior. In this paper weconcentrate on the numerical investigation of the microchannel flow for Kn < 0.01 and Re < 500. The channellength is finite. Hence, entrance and outlet effects on microchannel flow can be studied.
