Pulmonary vein isolation under direct visual identification of the left atrium-pulmonary vein junction using intra-cardiac echography.

INTRODUCTION: Intra-cardiac echocardiography (ICE) which has some benefits, can be used to obtain detailed anatomy of the heart chambers or large vessels, and the catheter positions, and it has been considered useful for improving the outcome of the ablation. In the present study, we performed pulmonary vein isolation (PVI) under real time monitoring of ICE imaging utilizing an ICE catheter placed at the junction of the left atrium (LA) and PVs (LA-PV junction). METHODS: PVI for atrial fibrillation (AF) was performed in 30 cases with drug-resistant AF (mean age: 66-years-old; including 22 males). An ICE catheter utilizing a 9 MHz frequency was inserted into the LA via the atrial septum, and placed at the LA-PV junction. Circumferential ablation was performed in the LA outside of the PV ostium, encircling both the superior and inferior ostia together under ICE imaging. RESULTS: The anatomy of the LA to the PVs and catheter sites were clearly identified by the ICE during the procedure, which enabled a precise and safe catheter manipulation with minimal fluoroscopy. Further, the wall thickness of the PV and LA, and position of the esophagus could be obtained by ICE, facilitating care in adjusting the power and/or duration of the current delivery. CONCLUSION: ICE imaging of the LA-PV junction permitted real time monitoring of the target sites for PVI during the ablation procedure, and was considered a useful technique for performing PVI.

The effect of acupuncture on uterine contraction induced by oxytocin.

Preterm labor (PTL) is one of the main causes of fetal mortality and morbidity in obstetrical medicine. Current methods of treatment are not very effective and often have significant side effects. For this reason new methods of preventing PTL are currently being sought. In Western medicine the newest development is oxytocin antagonists. In Oriental medicine acupuncture and moxibustion are being utilized for the purpose of stopping PTL. The goals of this study were to determine if acupuncture in pregnant rats can suppress oxytocin induced uterine contractions and to compare these results with those inhibited by an oxytocin antagonist. Uterine contractions were induced by continuous infusion of exogenous oxytocin. The first fetus in one uterine horn near the ovarian end was removed and distilled water-filled catheter was inserted into that vacated amniotic sac to measure uterine contractions as intrauterine pressure changes. Two acupoints of Ho-Ku (LI-4) and San-Yin-Chiao (Sp-6) were selected for acupuncture and Kuan-Yüan (Co-4) was used for moxibustion. The oxytocin-induced uterine contractions were significantly suppressed by acupuncture on the LI-4 (p < 0.05), but not by Sp-6. Stimulation of Co-4 by moxibustion had no significant (p > 0.05) tocolytic effect. The administration of oxytocin antagonist eliminated all the uterine contractions induced by oxytocin. The application of acupuncture to re-stimulate the activity that was suppressed by the oxytocin antagonist did not produce any positive results. However, prostaglandins did cause the uterus to contract. In conclusion, acupuncture on LI-4 was found to suppress uterine contractions induced by oxytocin in the pregnant rat. If acupuncture is similarly effective in counteracting the effects of oxytocin in women, then this may an alternative medical treatment for women in preterm labor.

General pharmacological properties of the new proton pump inhibitor (+/-)-5-methoxy-2-[[(4-methoxy-3,5-dimethylpyrid-2-yl)methyl]sulf inyl]- 1H-imidazo[4,5-b]pyridine.

The general pharmacological profiles of a novel proton pump inhibitor, (+/-)-5-methoxy-2-[[(4-methoxy-3,5-dimethylpyrid-2-yl)methyl]sulfi nyl]- 1H-imidazo[4,5-b]pyridine, TU-199) on the central nervous system, cardiorespiratory system, autonomic nervous system, gastrointestinal system and renal functions were investigated. TU-199 had no effects on general signs and behavior in mice. TU-199 (300 mg/kg p.o.) decreased locomotor activity 3 h after administration in mice. TU-199 had no effect on pentobarbital-induced hypnosis, analgesic activity and electroshock-induced convulsion in mice, and on rectal temperature in rats. However, TU-199 (300 mg/kg p.o.) showed slight anticonvulsant activity on pentylenetetrazole-induced convulsion in mice. TU-199 had no effect on respiratory rate, blood pressure, heart rate, femoral blood flow and electrocardiogram in anesthetized dogs. TU-199 (10(4) M) caused the cumulative concentration-response curve obtained with acetylcholine in isolated guinea pig ileum to shift to the right. However, TU-199 showed no effect on contraction of isolated guinea pig ileum and had no effect on intestinal motility in mice, gastric emptying in rats, bile secretion in rats and carbachol-induced salivary secretion in mice. TU-199 had no effect on urinary volume and excretion of electrolytes in rats. These results suggest that TU-199 does not induce serious adverse effects on the central nervous system, cardiorespiratory system, autonomic nervous system, gastrointestinal system and renal functions with the exception of a decrease in spontaneous motor activity with high doses.

The long-lasting effect of TU-199, a novel H+, K(+)-ATPase inhibitor, on gastric acid secretion in dogs.

We have used Heidenhain-pouch dogs to investigate the effects of (+/-)-5-methoxy-2-{[(4-methoxy-3,5-dimethylpyrid-2-yl)methyl]sulph inyl}-1H-imidazo[4,5-b]pyridine (TU-199), an imidazopyridine derivative, on gastric acid secretion stimulated by histamine, carbachol and tetragastrin. We have also investigated the duration of the antisecretory effect of TU-199 using a measurement of intragastric pH for 24 h in gastric fistula dogs whose gastric acid secretion was stimulated by histamine. Single oral administration of TU-199 (0.1, 0.2 and 0.4mgkg(-1)) dose-dependently suppressed gastric acid secretion stimulated by histamine infusion. Oral treatment with TU-199 (0.2, 0.4 and 0.8 mg kg(-1)) also dose-dependently inhibited acid secretion induced by carbachol and tetragastrin. The inhibitory effect of TU-199 on stimulated gastric acid secretion was more potent than that of omeprazole, a well-known H+,K(+)-ATPase inhibitor in dogs. Repeated oral treatment with TU-199 at a dose of 0.2 mg kg(-1) once a day for seven days markedly suppressed histamine-stimulated gastric acid secretion in dogs. This inhibitory effect of TU-199 reached a maximum level after three or four doses and was more pronounced than that of omeprazole or lansoprazole. In gastric fistula dogs, the duration of intragastric pH-elevation by administration of TU-199 (0.3 mg kg(-1)) was much longer than that of omeprazole (0.6mgkg(-1)) or lansoprazole (0.9mgkg(-1)). The IC50 values (doses resulting in 50% inhibition) of TU-199, omeprazole and lansoprazole with regard to H+,K(+)-ATPase activity in dog gastric mucosal microsomes were 8.6, 8.8 and 9.9 microM, respectively. These results indicate that TU-199 inhibits gastric acid secretion via suppression of a H+,K(+)-ATPase activity. Our findings also suggest that TU-199 might have potent and long-lasting effects on gastric acid secretion.

Effects of TU-199, a novel H+, K(+)-ATPase inhibitor, on gastric acid secretion and gastroduodenal ulcers in rats.

We studied the effects of TU-199, a novel H+, K(+)-ATPase inhibitor, on gastric acid secretion and gastroduodenal lesions in rats in comparison with those of omeprazole. TU-199 inhibited hog gastric H+, K(+)-ATPase activity and its potency was almost equal to that of omeprazole (IC50 = 6.2 and 4.2 microM, respectively). In vivo, TU-199 inhibited basal gastric acid secretion in pylorus-ligated rats in a dose-dependent manner (ED50 = 4.2 mg/kg p.o.). In gastric fistula rats. TU-199 (2.5 and 5 mg/kg i.d.) also inhibited gastric acid secretion stimulated by histamine, carbachol or tetragastrin. Furthermore, TU-199 prevented the formation of water-immersion restraint stress-, pylorus ligation- and indomethacin-induced gastric lesions, and mepirizole-induced duodenal ulcer in rats. These antisecretory and antiulcer effects of TU-199 were 2-4 times more potent than those of omeprazole. The results demonstrate that TU-199 potently inhibits the acid secretion and formation of ulcers in various experimental rat models via an inhibition of H+, K(+)-ATPase. These findings suggest that TU-199 may have a beneficial effect against peptic ulcer disease in humans.