BACKGROUND: The relaxative response of blood vessels to acetylcholine (ACh) is known to be abnormal in diabetic rat due to changes in endothelium-derived relaxing factor (EDRF) and/or endothelium-derived hyperpolarizing factor (EDHF)-mediated action. Oxygen free radical (OFR) interferes with endothelium dependent relaxation to ACh in diabetic rats; this effect rnay be prevented by superoxide dismutase (SOD), OFR scavenger. Then, we determined the effect of SOD on modulation of OFR-induced damage to EDRF and EDHF-mediated relaxations to ACh in diabetic rat aortas. METHODS: After aortas were incubated with free radical generating system for 15 min with or without SOD pretreatment (150 U/mL) and contracted submaximally by norepinephrine (10 (-5) M), relaxative responses to cumulative concentrations (10 (-9) M to 10 (-5) M) of ACh were measured in aortas isolated from the control and 6-8 week streptozotocin-induced diabetic rat. We measured relaxative responses to ACh in these aortas treated with calmidazolium (100uM) or N-nitro-L-arginine methyl ester (luM) after exposure to OFR with/without SOD pretreatment, RESULTS: The ACh-induced relaxation (10 (-9)M to 10 (-5) M) was significantly decreased in diabetic than in control rat aortas (p<0.05). ACh-induced relaxation in diabetic rat aortas was significantly impaired from 79.3% to 71.2% after exposure to OFR (p<0.05), and the degree of ACh-induced relaxation was recovered from 71.2% to 84.0% after pretreatment with SOD (p<0.05). EDRF-mediated relaxation to ACh in diabetic rat aortas was significantly impaired from 71.2% to 61.6% after exposure to OFR (p<0.05), and the degree of impairment of ACh-induced EDRF-mediated relaxation was recovered from 61.6% to 76.0% after pretreatment with SOD. After exposure to OFR, EDHF-mediated relaxation to ACh in diabetic rat aortas was not significanlty impaired. However, the degree of impairment of EDHF-mediated relaxation to ACh was recovered from 46.0% to 59.5% after pretreatment with SOD. CONCLUSION: This study suggests that OFR may impair mainly EDRF-mediated relaxation to ACh and SOD may protect rnainly OFR-induced damage to EDRF-mediated relaxation to ACh in diabetic rat aortas.
Acetylcholine ; Animals ; Aorta* ; Blood Vessels ; Endothelium ; Endothelium-Dependent Relaxing Factors ; Free Radicals* ; Norepinephrine ; Oxygen* ; Rats* ; Relaxation* ; Superoxide Dismutase* ; Superoxides*

We report two cases of mucinous ductal ectasia of the pancreas which showed characteristic pancreatoscopic findings. They also showed characteristic duodenoscopic findings such as patulous ampullary orifice and mucus leakage from the papilla, and underlying pathology was hyperplasia in one case and adenoma in the other case, The insertions of pancreatoscope into the main pancreatic duct were easy without previous sphincterotomy and whitish frog egg-like mucosa was noted in one case and finger-like papillary projection was noted in the other case.
Adenoma ; Dilatation, Pathologic* ; Hyperplasia ; Mucins* ; Mucous Membrane ; Mucus ; Pancreas* ; Pancreatic Ducts ; Pathology