| Co-Investigator(Kenkyū-buntansha) |
HAYASHI Nobuhiko Osaka University Hospital, Research Associate, 医学部附属病院, 医員
TSUJI Shingo Osaka University Hospital, Research Associate, 医学部附属病院, 医員
NAGANO Kouichi Osaka University, Department of Medicine, Assistant Professor, 医学部, 助手
KAWANO Sunao Osaka University, Department of Medicine, Assistant Professor, 医学部, 助手 (60133138)
FUSAMOTO Hideyuki Osaka University, Department of Medicine, Associate Professor, 医学部, 助教授 (90124776)
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| Research Abstract |
Endoscopic detection and treatment of early small cancers are important issues in clinical and social view points. Although convensional endoscopy have relied mainly on human eye, . computerized quantitation has been necessary for early detection of minute cancers in gastrointestinal tractlind bronchus. The investigators have developed computer-assisted electronic endoscopes which are also equ i"!% with near infrared and near suprapurple light source. This endoscopic system is possible to analyze tissue blood hemoglobin distribution at 30, 000 points with a resolution less than 0.01 mm^2/point. The system also detects submucosal vasculature in the gastrointestinal mucosa. Microheterogeneity of gastrointestinal mucosal hemodynamics and subrnucosal vascular responses were investigated in normal subjects and patients with various disorders including peptic ulcer, gastric cancer and various chronic gastritis. The cell proliferation and aniploidity of these subjects were also analyzed by fl
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owcytometry. Furthermore, an algorithm was developed to analyze oxygen saturation of a single capillary for more. precise analysis of tissue hemodynamics.
Helicobacter pylori infection has been reported an important epidemiological factor of gastric cancer as well as chronic atrophic gastritis. In an animal experiment, ammonia, which is a product of Helicobacter, was chronically administered to rats. The results revealed that ammonia attenuates mucosal cellular energy metabolism, decreases intracellular mucin content, and increases mucosal cell exfoliation and cell proliferation. Cell population and mucosal histological appearance including gastric vasculature also changed. These changes are quite consistent with those of human gastric mucosa which are shown by the infrared electronic endoscopy. Moreover, another experiment have shown that ammonia is a potent promoter of gastric cancer.
Although endoscopic photodynamic therapy, endoscopic resection and endoscopic chemotherapy have been important modalities for treatment of early gastric cancer, these therapy have not distributed widely because of possible remission of the disease. The investigators also examined the effects of various agents on gastrointestinal hemodynamics using the infrared endoscopic system. Ethanol stimulates endothelin-1 and leukotriene releases and causes gastric mucosal blood flow stasis, while a certain antiinflammatory drug decreases mucosal blood hemoglobin content. Possible synergic effect of these agents on endoscopic therapies and development of computer-controlled endoscopic treatment system remain to be examined in the further investigations. Less
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