Shigenobu Ueda
Kyoto Prefectural University of Medicine
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Featured researches published by Shigenobu Ueda.
Free Radical Research | 1991
Toshikazu Yoshikawa; Yuji Naito; Toru Tanigawa; Tomoyuki Yoneta; Mitsunori Yasuda; Shigenobu Ueda; H. Oyamada; Motoharu Kondo
The protective effect of a novel synthetic zinc-carnosine chelate compound, zinc N-(3-aminopropionyl)-L-histidine (Z-103), on the gastric mucosal injury induced by ischemia-reperfusion was studied in rats. Ischemia and reperfusion injury was produced on the rat stomach by applying a small clamp to the celiac artery for 30 min and by removal of the clamp for 30 min. The decrease in the gastric mucosal blood flow was not influenced by the treatment with Z-103. The increase in total area of the erosions on the stomach after ischemia-reperfusion and the increase in lipid peroxides in the gastric mucosa were significantly inhibited by the oral administration of Z-103. In addition, Z-103 inhibited lipid peroxidation of rat brain homogenate and liver microsome in vitro. These results suggest that the protective effect of Z-103 against the aggravation of gastric mucosal injury induced by ischemia-reperfusion may be due to its inhibitory effect on lipid peroxidation.
Journal of Clinical Gastroenterology | 1990
Toshikazu Yoshikawa; Yuji Naito; Shigenobu Ueda; Hirokazu Oyamada; Toshiki Takemura; Norimasa Yoshida; Shigeru Sugino; Motoharu Kondo
The role of oxygen-derived free radicals and lipid peroxidation in the pathogenesis of acute gastric mucosal erosion was investigated in rat models produced by burn shock stress, by treatment with regional hyperthermia, platelet activating factor, and compound 48/80, and by ischemia-reperfusion. In all experimental models, the increase in the gastric erosions and in TBA reactants in the gastric mucosa were significantly inhibited by the treatment with superoxide dismutase (SOD) and/or catalase. Pretreatment with allopurinol, a competitive inhibitor of xanthine oxidase, prevented considerably the gastric injury (a) induced by burn shock, (b) produced by treatment with compound 48/80, and (c) caused by ischemia-reperfusion. By the treatment with anti-rat neutrophil antibody, the gastric mucosal injuries induced by regional hyperthermia, platelet activating factor, and compound 48/80 were significantly inhibited; however, burn shock and ischemia-reperfusion injuries were not inhibited. These results suggest that oxygen-free radical and lipid peroxidation contribute to the formation of gastric mucosal lesions, and that the sources of oxygen radicals seem to be different among these experimental models.
Scandinavian Journal of Gastroenterology | 1989
Shigenobu Ueda; Toshikazu Yoshikawa; S. Takahashi; Hiroshi Ichikawa; Mitsunori Yasuda; H. Oyamada; Toru Tanigawa; Shigeru Sugino; Motoharu Kondo
Ischemia and reperfusion is of the greatest importance in the pathology of various diseases. This study was designed to investigate the role of oxygen-derived free radicals and lipid peroxidation in gastric mucosal injury induced by ischemia-reperfusion in rats. Clamping of the celiac artery in rats reduced the gastric mucosal blood flow to 10% of that measured before the clamping. Gastric mucosal injury, such as spotty and linear hemorrhagic erosions, was seen in rats 60 min of the reperfusion following 30 min of ischemia. Thiobarbituric acid (TBA) reactants in the gastric mucosa were increased after the reperfusion. The increase in gastric mucosal lesions and TBA reactants were significantly inhibited by the treatment with SOD+ catalase and allopurinol. These results suggest that oxygen-derived free radicals and lipid peroxidation may play an important role in the pathogenesis of acute gastric mucosal lesions induced by ischemia-reperfusion.
International Journal of Immunopharmacology | 1992
Toshikazu Yoshikawa; Hirohisa Takano; Yuji Naito; H. Oyamada; Shigenobu Ueda; Motoharu Kondo
We investigated the effects of tumor necrosis factor-alpha (human, natural type: n-TNF) on polymorphonuclear leukocyte (PMN)-derived superoxide generation by the new method of Cypridina luciferin analog-dependent chemiluminescence, which had high sensitivity and specificity to superoxide. Preincubation of PMNs with n-TNF for 3 min increased PMN-derived superoxide generation induced by phorbol myristate acetate, A23187, opsonized zymosan and N-formyl-methionyl-leucyl-phenylalanine in a concentration dependent manner (0.5-50 Japan reference units/ml of n-TNF). In addition, the enhanced PMN-derived superoxide generation by n-TNF showed a positive correlation to the preincubation time of PMNs with n-TNF (3-15 min). However, a direct incubation of PMNs with n-TNF for 1 h did not induce superoxide from PMNs without the above stimulants. The augmentative effects of n-TNF on PMN-derived superoxide generation should be useful in the PMN-mediated host defense mechanism, such as bactericidal and antitumor activity. The local concentration of n-TNF and the n-TNF-PMN contact time are considered very important in obtaining these effects more efficiently in addition to the presence of PMN-stimulants including complements, chemotactic peptides and phorbol esters.
Advances in Experimental Medicine and Biology | 1990
Toshikazu Yoshikawa; Yuji Naito; H. Oyamada; Shigenobu Ueda; Toru Tanigawa; Toshiki Takemura; Shigeru Sugino; Motoharu Kondo
Rooibos tea ia a totally unique South African product of the plantAspalathus linealis which is only produced in the Cadarberg mountains around Clanwilliam. In South Africa it is mainly used as a substitute for the Oriental black tea by people who enjoy it either hot or cold, or by those who regard it as a healthy drink. Clinically, Rooibos tea is often prescribed for nervous tension, allergies, stomach and digestive problems. For evaluation of its antioxidant action, reactivity of Aspalathus linealis, ascorbic acid, and quercetin which is one of non-glycosidically linked flavonoids included in Asparathus linealis, to various reactive oxygen species were assessed by electron spin resonance (ESR) sipectrometry using 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) as a spin trapper1,2.
Journal of Clinical Gastroenterology | 1992
Yuji Naito; Toshikazu Yoshikawa; Takashi Ando; Akihiko Kishi; Shigenobu Ueda; Hirokazu Oyamada; Motoharu Kondo
A highly sensitive chemiluminescence method for determining superoxide dismutase (SOD) activities in human gastric mucosa obtained by endoscopic biopsy is described. As the chemiluminescence probe, we used Cypridina luciferin analogue (CLA), a very sensitive and specific probe to detect superoxide generated from hypoxanthine–xanthine oxidase system. SOD activity in the gastric mucosa was assayed by the inhibition of CLA-dependent chemiluminescence in highly diluted tissue homogenates. SOD activity was distributed throughout the gastric mucosa. The marginal mucosa of peptic ulcers showed significantly lower SOD activity when the ulcer was in the active stage, and during the healing stage showed high activity when compared to the endoscopically normal adjacent mucosa of the same patients. The preliminary data suggest that enzymatic SOD in the gastric mucosa may play an important role in the pathogenic and healing processes of human peptic ulcers.
Advances in Experimental Medicine and Biology | 1990
Shigenobu Ueda; Toshikazu Yoshikawa; S. Takahashi; Yuji Naito; H. Oyamada; Toshiki Takemura; Yutaka Morita; Toru Tanigawa; Shigeru Sugino; Motoharu Kondo
Several pathogenetic mechanisms have been suggested to account for acute gastric mucosal injury. Recently, Oxigen-derived free radicals and lipid peroxidation have been suggested to play a role in the pathogenesis of gastric mucosal injury1,2,3). Ischemia and reperfusion are of the greatest importance in the pathology of many diseases. There has been great interest in the possible role of oxygen radical species in ischemia-reperfusion in the gastric mucosa4). A synthetic seleno-organic compound, 2-phenyl-1, 2 benzoisoselenazol-3(2H)-one(Ebselen), shows a glutathione peroxidase(GSHPx)-like activity-5,6). This study was designed to examine the protective effects of the agent, Ebselen against the gastric mucosal injury induced by ischemia-reperfusion.
Lipids | 1992
Toshikazu Yoshikawa; Shuji Takahashi; Yuji Naito; Shigenobu Ueda; Toru Tanigawa; Norimasa Yoshida; Motoharu Kondo
Recent research was shown that oxygen-derived free radicals are involved in the pathogenesis of various diseases, including ischemia-reperfusion injury. We have also reported that oxygen-derived free radicals and lipid peroxidation may play an important role in gastric mucosal injury induced by ischemia-reperfusion. The hypoxanthinexanthine oxidase system and neutrophils are considered important sources of oxygen-derived free radicals in this process. In recent years, it also has been shown that serum platelet-activating factor (PAF) levels increased during ischemia-reperfusion, and that induction of superoxide generation by neutrophils is one of the important biological effects of PAF. In the present study, we examined the effect of CV-6209, a specific PAF receptor antagonist, on gastric mucosal injury induced by ischemia-reperfusion, to shed some light on the possible involvement of PAF in such lesions. CV-6209 significantly attenuated the gastric mucosal injury induced by ischemia-reperfusion, and inhibited both an increase of thiobarbituric acid reactive substances and a decrease of α-tocopherol in gastric mucosa after ischemia-reperfusion. However, CV-6209 had no effect on gastric mucosal blood flow during ischemiano effect on gastric mucosal blood flow during ischemia-reperfusion. These results suggest that endogenous PAF may play an important role in gastric mucosal injury induced by ischemia-reperfusion, and that CV-6209 exerts its beneficial effect mainly by inhibiting neutrophil superoxide production induced by PAF.
Advances in Experimental Medicine and Biology | 1990
Toru Tanigawa; Toshikazu Yoshikawa; Yuji Naito; Tomoyuki Yoneta; Shigenobu Ueda; H. Oyamada; Toshiki Takemura; Yutaka Morita; Kenzo Tainaka; Norimasa Yoshida; Shigeru Sugino; Motoharu Kondo
The objective of the present study was to examine the anti-free radical action of Z-103 in vitro. Z-103 is a novel synthetic compound of zinc and carnosine (β-alanyl-L-histidine) which has strong anti-ulcer action in many types of animal models.1Free radicals have come to considered to be playing a role in the pathogenesis of gastric mucosal injuries2,3. The antifree radical action of Z-103 were expected because zinc and carnosine have antioxidative properties4,5. To know its anti-free radical action in vitro will be significant to understand its mechanism of action as anti-ulcer drug.
Advances in Experimental Medicine and Biology | 1990
Toshiki Takemura; Toshikazu Yoshikawa; Yuji Naito; Shigenobu Ueda; Toru Tanigawa; Shigeru Sugino; Motoharu Kondo
Recent studies have demonstrated that active oxygen species and lipid peroxidation might be involved in the formation of gastric mucosal lesions1–3. Compound 48/80 is a mast cell degranulator to release histamine and serotonin. Repeated administration of a small dose of this agent can induce gastric mucosal injury in rats with a low mortality rate4. This study was designed to evaluate a role of active oxygen species and lipid peroxidation in the pathogenesis of gastric mucosal injury induced by compound 48/80 in rats. Fur- thermore, the role of xanthine-xanthine oxidase systems and polymorphonuclear leukocytes (PMN) for the source of active oxygen species was examined.