A useful helicobacter pylori-induced gastritis model using BALB/c mice was established for mimicking of human gastritis induced by Helicobacter pylori (H. pylori). The H. pylori isolates were obtained freshly from a...A useful helicobacter pylori-induced gastritis model using BALB/c mice was established for mimicking of human gastritis induced by Helicobacter pylori (H. pylori). The H. pylori isolates were obtained freshly from a human complex ulcer patient. BALB/c mice were fasted for 24 h and then 0.25 mL of 0.2 mol·L -1 NaHCO 3 was administered after by gavage to each mouse and 0.5 mL of 10 9 colonies formation unit per milliliter (CFU/mL) of H. pylori was administered 15 min. On the 3 rd day and 5 th day, the H. pylori inoculations were repeated. The inoculated mice were sacrificed in batch on the 5 th day, in the 2 nd week, 3 rd week and 4 th week. The gastric mucous membrane near pyloric portion was removed, treated and then cultured under microaerobic condition for detection of H.pylori. The remainders of the gastric membrane were fixed by 10% formaldehyde solution for pathological detection. The results showed that the H. pylori could be separated from the gastric membranes of inoculated mice. Obvious invasion of inflammatory cells in the gastric membranes of inoculated mice could be observed from pathological sections. It can be concluded that the inoculating fresh human H. pylori isolates can produce mouse gastritis. This model of BALB/c mice can be used for evaluating the therapeutic agents for the treatment of gastritis induced by H. pylori.展开更多
Although various animal models have been developed to clarify gastric carcinogenesis, apparent mechanism of gastric cancer was not clarified in recent years. Since the recognition of the pathogenicity of Helocobacter ...Although various animal models have been developed to clarify gastric carcinogenesis, apparent mechanism of gastric cancer was not clarified in recent years. Since the recognition of the pathogenicity of Helocobacter pylori（H pylori）, several animal models with H pylori infection have been developed to confirm the association between Hpylori and gastric cancer. Nonhuman primate and rodent models were suitable for this study. Japanese monkey model revealed atrophic gastritis and p53 mutation after long-term infection of Hpylori. Mongolian gerbil model showed the development of gastric carcinoma with H pylori infection alone, as well as with combination of chemical carcinogens, such as N-methyl- N-nitrosourea and N-methyl-N-nitro-N＇-nitrosoguanidine. The histopathological changes of these animal models after H pylori inoculation are closely similar to those in human beings with Hpylori infection. Eradication therapy attenuated the development of gastric cancer in Hpylori- infected Mongolian gerbil. Although several features of animal models differ from those seen in human beings, these experimental models provide a starting point for further studies to clarify the mechanism of gastric carcinogenesis as a result of Hpylon infection and assist the planning of eradication therapy to prevent gastric carcinoma.展开更多
Despite decreasing incidence and mortality rates, gastric cancer (GC) still remains the fourth most common cancer and the second most common cause of cancer-related deaths worldwide. Due to the limited treatment optio...Despite decreasing incidence and mortality rates, gastric cancer (GC) still remains the fourth most common cancer and the second most common cause of cancer-related deaths worldwide. Due to the limited treatment options, at present, prevention is likely to be the only effective means of controlling this disease. The success of a prevention strategy depends upon the understanding of etiological and pathogenic mechanisms underlying gastric carcinogenesis. The etiology of GC is multi-factorial, however, in the recent years, mounting evidence suggests that environmental factors play a key role. The most important environmental factors implicated in the pathogenesis of GC are diet and H pylori infection. Thus, modifications in lifestyle and dietary habit associated with eradication of H pylori infection could hypothetically represent the most promising potential targets for GC prevention. In this review we will address the evidence and the controversies on the role of these agents in noncardia GC by focusing on retrospective and prospective observational studies and interventional trials.展开更多
AIM: To investigate the effectiveness of 4 d' anti-Helicobacter pylori therapy on the H pylori-infected Mongolian gerbils based on physiological and pathological changes. METHODS: We used 6-wk-old male gerbils ora...AIM: To investigate the effectiveness of 4 d' anti-Helicobacter pylori therapy on the H pylori-infected Mongolian gerbils based on physiological and pathological changes. METHODS: We used 6-wk-old male gerbils orally inoculated with H pylori (ATCC43504, 2×108 CFU/mL). Seven weeks after H pylori inoculation, the animals of study group received 4 d' anti-H pylori triple therapy (H pylori-eradicated group). Seven days later, all animals of the H pylori-eradicated and control groups (H pylori-infected & H pylori-uninfected groups) were sacrificed. We examined gastric mucosal lesions macroscopically, studied gastritis microscopically and determined the stomach weight ratio, myeloperoxidase (MPO) activity and prostaglandin (PG) E2 level. RESULTS: The results showed that both macroscopic and histological gastric damages were significantly less in H pylori-eradicated group than H pylori-infected group. Stomach weight ratio, MPO activity and PGE2 levels were significantly higher in H pylori-infected group than those in the other two groups. CONCLUSION: Four days' anti-H pylori therapy was effective in the improvement of H pylori-induced gastric lesions in Mongolian gerbils.展开更多
The transmission shaft of the underground screw drill fractured when milling-shoe and grinding bridge plug was applied to the coiled tubes in a horizontal well of Sichuan province, but the position of this transmissio...The transmission shaft of the underground screw drill fractured when milling-shoe and grinding bridge plug was applied to the coiled tubes in a horizontal well of Sichuan province, but the position of this transmission shaft fracture did not occur at the minor-diameter retracting position and reducing position that were easy to fracture. An analysis of the transverse planes of the fracture found that the cause of the transmission shaft fracture surface was that the defects of the initial surface were propagating to cracks and gave rise to the fracture under torque load. To specifically know well the strength of the transmission shaft under damaging fracture, a statics analysis was conducted on the transmission shaft through ANSYS finite element simulation software, and the finite element models under no cracks, different-depth circumferential cracks, and similar situation of the transverse planes of fracture were established respectively. An analysis of the crack-free finite element model found that the fracture of the transmission shaft was really not caused by the self-structure of the transmission shaft; an analysis of circumferential crack finite element model found that strong stress concentration would appear in the tip of cracks, and the value of the stress would increase along with the increase of the circumferential crack depth, the stress of the entire crack top tended to fluctuate like waves, and also the strength of the transmission shaft was greatly impacted by the presence of cracks; an analysis of the similar crack finite element model found that stress concentration would appear in the tip of cracks, and the initial cracks always started to propagate from the tip of the external surface of the transmission shaft and would propagate inward until the propagating areas of two cracks overlapped, and finally reached the position of transient interruption, and then the transmission shaft fractured completely and the fracture strength was onlv 1/5 of that under no cracks.展开更多
文摘A useful helicobacter pylori-induced gastritis model using BALB/c mice was established for mimicking of human gastritis induced by Helicobacter pylori (H. pylori). The H. pylori isolates were obtained freshly from a human complex ulcer patient. BALB/c mice were fasted for 24 h and then 0.25 mL of 0.2 mol·L -1 NaHCO 3 was administered after by gavage to each mouse and 0.5 mL of 10 9 colonies formation unit per milliliter (CFU/mL) of H. pylori was administered 15 min. On the 3 rd day and 5 th day, the H. pylori inoculations were repeated. The inoculated mice were sacrificed in batch on the 5 th day, in the 2 nd week, 3 rd week and 4 th week. The gastric mucous membrane near pyloric portion was removed, treated and then cultured under microaerobic condition for detection of H.pylori. The remainders of the gastric membrane were fixed by 10% formaldehyde solution for pathological detection. The results showed that the H. pylori could be separated from the gastric membranes of inoculated mice. Obvious invasion of inflammatory cells in the gastric membranes of inoculated mice could be observed from pathological sections. It can be concluded that the inoculating fresh human H. pylori isolates can produce mouse gastritis. This model of BALB/c mice can be used for evaluating the therapeutic agents for the treatment of gastritis induced by H. pylori.
文摘Although various animal models have been developed to clarify gastric carcinogenesis, apparent mechanism of gastric cancer was not clarified in recent years. Since the recognition of the pathogenicity of Helocobacter pylori（H pylori）, several animal models with H pylori infection have been developed to confirm the association between Hpylori and gastric cancer. Nonhuman primate and rodent models were suitable for this study. Japanese monkey model revealed atrophic gastritis and p53 mutation after long-term infection of Hpylori. Mongolian gerbil model showed the development of gastric carcinoma with H pylori infection alone, as well as with combination of chemical carcinogens, such as N-methyl- N-nitrosourea and N-methyl-N-nitro-N＇-nitrosoguanidine. The histopathological changes of these animal models after H pylori inoculation are closely similar to those in human beings with Hpylori infection. Eradication therapy attenuated the development of gastric cancer in Hpylori- infected Mongolian gerbil. Although several features of animal models differ from those seen in human beings, these experimental models provide a starting point for further studies to clarify the mechanism of gastric carcinogenesis as a result of Hpylon infection and assist the planning of eradication therapy to prevent gastric carcinoma.
文摘Despite decreasing incidence and mortality rates, gastric cancer (GC) still remains the fourth most common cancer and the second most common cause of cancer-related deaths worldwide. Due to the limited treatment options, at present, prevention is likely to be the only effective means of controlling this disease. The success of a prevention strategy depends upon the understanding of etiological and pathogenic mechanisms underlying gastric carcinogenesis. The etiology of GC is multi-factorial, however, in the recent years, mounting evidence suggests that environmental factors play a key role. The most important environmental factors implicated in the pathogenesis of GC are diet and H pylori infection. Thus, modifications in lifestyle and dietary habit associated with eradication of H pylori infection could hypothetically represent the most promising potential targets for GC prevention. In this review we will address the evidence and the controversies on the role of these agents in noncardia GC by focusing on retrospective and prospective observational studies and interventional trials.
文摘AIM: To investigate the effectiveness of 4 d' anti-Helicobacter pylori therapy on the H pylori-infected Mongolian gerbils based on physiological and pathological changes. METHODS: We used 6-wk-old male gerbils orally inoculated with H pylori (ATCC43504, 2×108 CFU/mL). Seven weeks after H pylori inoculation, the animals of study group received 4 d' anti-H pylori triple therapy (H pylori-eradicated group). Seven days later, all animals of the H pylori-eradicated and control groups (H pylori-infected & H pylori-uninfected groups) were sacrificed. We examined gastric mucosal lesions macroscopically, studied gastritis microscopically and determined the stomach weight ratio, myeloperoxidase (MPO) activity and prostaglandin (PG) E2 level. RESULTS: The results showed that both macroscopic and histological gastric damages were significantly less in H pylori-eradicated group than H pylori-infected group. Stomach weight ratio, MPO activity and PGE2 levels were significantly higher in H pylori-infected group than those in the other two groups. CONCLUSION: Four days' anti-H pylori therapy was effective in the improvement of H pylori-induced gastric lesions in Mongolian gerbils.
文摘The transmission shaft of the underground screw drill fractured when milling-shoe and grinding bridge plug was applied to the coiled tubes in a horizontal well of Sichuan province, but the position of this transmission shaft fracture did not occur at the minor-diameter retracting position and reducing position that were easy to fracture. An analysis of the transverse planes of the fracture found that the cause of the transmission shaft fracture surface was that the defects of the initial surface were propagating to cracks and gave rise to the fracture under torque load. To specifically know well the strength of the transmission shaft under damaging fracture, a statics analysis was conducted on the transmission shaft through ANSYS finite element simulation software, and the finite element models under no cracks, different-depth circumferential cracks, and similar situation of the transverse planes of fracture were established respectively. An analysis of the crack-free finite element model found that the fracture of the transmission shaft was really not caused by the self-structure of the transmission shaft; an analysis of circumferential crack finite element model found that strong stress concentration would appear in the tip of cracks, and the value of the stress would increase along with the increase of the circumferential crack depth, the stress of the entire crack top tended to fluctuate like waves, and also the strength of the transmission shaft was greatly impacted by the presence of cracks; an analysis of the similar crack finite element model found that stress concentration would appear in the tip of cracks, and the initial cracks always started to propagate from the tip of the external surface of the transmission shaft and would propagate inward until the propagating areas of two cracks overlapped, and finally reached the position of transient interruption, and then the transmission shaft fractured completely and the fracture strength was onlv 1/5 of that under no cracks.
