Abstract. The effects of selective inhibitors of phosphodiesterase type IV (PDE4) on ischemiareperfusion-induced gastric injuries were investigated in rats. Gastric ischemia was induced by applying a small clamp to the celiac artery, and reoxygenation was performed by removal of the clamp. Ischemia-reperfusion produced gastric hemorrhagic injuries and increased the content of the proinflammatory cytokine tumor necrosis factor-a (TNF-a ) and myeloperoxidase (MPO) activity in gastric mucosa. Rolipram (0.03 -0.3 mg / kg, s.c.) and Ro-20-1724 (0.3 -3 mg/ kg, s.c.) prevented the development of gastric injury in a dose-dependent manner, and it also inhibited the increase in mucosal TNF-a content and MPO activity induced by ischemiareperfusion. The anti-ulcer drug irsogladine (1 -10 mg / kg, p.o.), which is known to possess a PDE4 inhibitory action, also inhibited the gastric injury produced by ischemia-reperfusion, as well as the increase in TNF-a levels and MPO activity. It is concluded that the ability of PDE4 inhibitors to inhibit cytokine TNF-a synthesis and the infiltration of polymorphonuclear leukocytes underlies their gastroprotective effects in ischemia-reperfusion-induced gastric injury. Our experiments suggest that drugs that inhibit PDE4 isoenzyme, such as the anti-ulcer drug irsogladine, may be a useful adjunct therapy for the treatment of the gastric damage that follows ischemia-reperfusion.
A transgalactosylation reaction from lactose to moranoline (1-deoxynojirimycin) was accomplished by using beta-galactosidase [EC 3.2.1.23] from Bacillus circulans. The enzyme formed 3-O-beta-D-galactopyranosyl-moranoline and 4-O-beta-D-galactopyranosyl-moranoline as major products, together with 2-O-beta-D-galactopyranosyl-moranoline and 6-O-beta-D-galactopyranosyl-moranoline as minor ones.
The blocked-N-terminal structure of hog kidney aldose 1-epimerase (mutarotase, EC 5.1.3.3) was determined to be Ac-Val-Ser-Val-Thr-Arg-Ser-Val-Phe-Gly-Asp... by a coupling of conventional methods (enzymatic digestion, amino acid analysis, and Edman sequencing) and tandem mass spectrometry. The side-chain fragmentations observed in the high-energy product ion spectra gave unambiguous sequence information about the arginine-containing N-terminal structure.
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