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101.
102.
Angiotensin within the central nervous system appears to be important for the maintenance of hypertension in spontaneously hypertensive rats. This study addresses the hypothesis that blockade of AT1 receptors in the rostral ventrolateral medulla would decrease blood pressure in spontaneously hypertensive rats and that this tonically active AT1-mediated input to the rostral ventrolateral medulla arises from the hypothalamic paraventricular nucleus. Injection of the nonpeptide AT1 receptor antagonist valsartan bilaterally into the rostral ventrolateral medulla of choralose-anesthetized adult spontaneously hypertensive rats produced a dose-related decrease in mean arterial pressure, with a maximal effect of approximately 30 mm Hg. Inhibition of the paraventricular nucleus by local injection of muscimol elicited a similar response, which was inhibited by prior injection of valsartan into the rostral ventrolateral medulla. In contrast, in control Wistar-Kyoto rats, neither valsartan injected into the rostral ventrolateral medulla nor muscimol injected into the paraventricular nucleus had a substantial effect on arterial pressure. These data indicate that in spontaneously hypertensive rats but not in Wistar-Kyoto rats, rostral ventrolateral medulla vasomotor neurons are tonically excited by endogenous stimulation of AT1 receptors, and this input is apparently driven from the hypothalamus. These results suggest that the rostral ventrolateral medulla is one site that the brain renin-angiotensin system acts to maintain elevated blood pressure in spontaneously hypertensive rats. 相似文献
103.
104.
Hisatomi Arima Yutaka Kiyohara Yumihiro Tanizaki Yusaku Nakabeppu Michiaki Kubo Isao Kato Katsuo Sueishi Masazumi Tsuneyoshi Masatoshi Fujishima Mitsuo Iida 《Circulation journal》2002,66(11):1034-1036
Previous studies have suggested that archival materials from formalin-fixed paraffin-embedded blocks are unsuitable for most molecular techniques because the extracted DNA can be severely degraded. Therefore, the present study was designed to investigate the accuracy of genotyping for the insertion (I)/deletion (D) polymorphism of the angiotensin-converting enzyme (ACE) gene from paraffin-embedded tissues of autopsy cases from Hisayama Town, Japan. The genotype was determined using the double polymerase chain reaction method and to test the accuracy of the method, the polymorphism was investigated using paraffin-embedded tissues from 18 cases whose ACE genotypes (6 cases for each genotype) were known in advance from analysis of fresh-frozen tissue samples. Genotyping using paraffin-embedded tissues was then determined for 968 autopsy subjects. The genotype could be determined in 16 of the 18 test samples (88.9%) and there was no discrepancy with the results obtained from the fresh-frozen tissues. Of the 968 autopsy cases, the frequency of the DD, ID, and II genotypes was 12.4%, 47.3%, and 40.3%, respectively, a distribution that did not deviate from the Hardy-Weinberg equilibrium (chi(22df )= 0.67, p=0.72). These findings suggest the accuracy of the present method of ACE genotyping from paraffin-embedded tissues. 相似文献
105.
Su JZ Fukuda N Jin XQ Lai YM Suzuki R Tahira Y Takagi H Ikeda Y Kanmatsuse K Miyazaki H 《Hypertension》2002,40(6):853-858
We recently reported that overexpression of the angiotensin II type 2 (AT2) receptor downregulates the AT1a receptor through the bradykinin/NO pathway in a ligand-independent manner in vascular smooth muscle cells (VSMCs). In the present study, we investigated the effect of AT2 receptor overexpression on the expression of the AT1a receptor and transforming growth factor-beta (TGF-beta) receptor subtypes in VSMCs from spontaneously hypertensive rats (SHR) and Wistar-Kyoto rats (WKY). Transfection of the AT2 receptor gene downregulated expression of the AT1a receptor in VSMCs from WKY, but did not affect expression of the AT1a receptor in VSMCs from SHR. Transfection of the AT2 receptor abolished DNA synthesis in response to angiotensin II in VSMCs from WKY; in VSMCs from SHR, basal DNA synthesis was suppressed, but DNA synthesis in response to Ang II was not altered. The NO substrate L-arginine augmented downregulation of the AT1a receptor in VSMCs from WKY, whereas it did not affect expression of the AT1a receptor in VSMCs from SHR. In response to AT2 receptor transfection, expression of TGF-beta type I receptor mRNA was suppressed significantly in VSMCs from WKY, whereas expression of TGF-beta type I receptor was not altered in VSMCs from SHR. These results suggest that the AT2 receptor downregulates AT1a and TGF-beta type I receptors in normal VSMCs, but not in SHR-derived VSMCs. The lack of downregulation of the AT1a receptor may contribute, in part, to the exaggerated growth of VSMCs from SHR. 相似文献
106.
The relationship between changes in intracellular free calcium concentration (Cai2+) and cell functions is becoming more clear, since it has become possible to measure Cai2+ in a living cell. There are, however, still unsolved questions concerning the role of Ca2+ in cellular signal transmission. It is not easy to relate Ca2+ signalling to the functions of a living cell. It is possible to control the amount of Ca2+ using calcium channel blockers, but it is still almost impossible to elucidate the relationship between Ca2+ and cellular functions by controlling Ca2+ signalling. One approach to solving this problem is to develop and use protein kinase inhibitors. Inhibitors specific to Ca2+/calmodulin-dependent protein phosphorylation, which is one of the important network systems of the Ca2+ signalling, attract interest among many researchers. The substances that can control Ca2+ signalling include: 1) calcium channel blockers, 2) calmodulin antagonists, and 3) Ca2+/calmodulin-dependent protein kinase inhibitors. Each substance has a different site of action. In this article, the action of KN-62, an inhibitor specific for Ca2+/calmodulin protein kinases (CaM kinases) will be described. 相似文献
107.
Shigemasa Tani Ikuyoshi Watanabe Ken Nagao Kimio Kikushima Kazuhiro Watanabe Takeo Anazawa Hirofumi Kawamata Eizo Tachibana Shingo Furuya Toshifumi Sasanuma Toshio Kushiro Katsuo Kanmatsuse 《Circulation journal》2004,68(9):853-859
BACKGROUND: Calcium channel blockers (CCBs) may have a positive influence on the long-term prognosis of Japanese patients with ischemic heart disease. METHODS AND RESULTS: The effect of nifedipine-retard (NR) (n=202) compared with that of non-CCB treatment (n=92) on the secondary prevention of myocardial infarction (MI) was retrospectively investigated in patients who had survived acute MI between 1987 and 1996. The primary endpoint was the occurrence of cardiac death or non-fatal MI. The median follow-up was 6.3+/-2.4 years. The incidence of cardiac events was 8.9% in the NR group and 14.1% in the non-CCBs group (p=0.14, odds ratio (OR): 0.584, 95% confidence interval (CI): 0.286-1,193). However, subanalysis revealed that NR significantly reduced the incidence of cardiac events in patients aged less than 55 years (4.2 vs 18.2%, p=0.016, OR: 0.180, 95%CI: 0.045-0.721) and those who did not smoke (8.6 vs 16.4%, p=0.048, OR: 0.462, 95%CI: 0.203-0.999). CONCLUSION: Although this was a retrospective analysis, it showed that NR did not cause an increase in the incidence of cardiac events in post-MI patients; it even prevented cardiac events, especially in those who were less than 55 years of age and in non-smokers, suggesting the potential usefulness of CCBs in the secondary prevention of MI in Japan. 相似文献
108.
Effect of mosapride on glycemic control and gastric emptying in type 2 diabetes mellitus patients with gastropathy 总被引:3,自引:0,他引:3
Delay of gastric emptying is one of the factors responsible for unfavorable glycemic control. We investigated the possible effects of mosapride, a digestive tract prokinetic agent, on glycemic control in diabetic patients complicated with gastropathy. Enrolled were 36 type II diabetic patients presenting with mild digestive tract symptoms. They were given mosapride 15 mg per day for 6 months. Seventeen cases were subjected to gastric emptying test according to marker method (administration of a capsule containing 20 pieces of radiopaque marker during breakfast, followed by abdominal X-ray imaging 3 and 5 h later). In 18 cases, HbA(1C) was improved by more than 0.3% for 6 months, whereby these 18 cases were defined as the improvement group. The remaining 18 cases were defined as the non-improvement group. In the gastric emptying study, basal number of the residual markers before administration of mosapride was determined 3 and 5 h later to show 18.3+/-1.8 and 7.6+/-5.1, respectively, in the improvement group while after administration, they were reduced down to 11.2+/-5.1 and 1.4+/-2.5, respectively. In sharp contrast, the basal counterparts in the non-improvement group were 19.1+/-1.5, and 16.4+/-3.4, respectively, whereas administration failed to reduce the number of the residual markers and they remained to be as high as 19.0+/-1.4 and 11.1+/-6.4, respectively. Gastric motility in the improvement group was much more improved by mosapride administration relative to those in the non-improvement group. Mosapride might elicit improvement in the glycemic control in the patients with diabetic gastropathy. 相似文献
109.
110.
Ichiro Watanabe Riko Masaki Nuo Min Naohiro Oshikawa Kimie Okubo Hidezou Sugimura Toshiaki Kojima Satoshi Saito Yukio Ozawa Katsuo Kanmatsuse 《Journal of interventional cardiac electrophysiology》2002,6(1):9-16
Since myocardial lesion size during radio-frequency (RF) ablation is limited at high power by impedance rise when electrode tip temperature exceed 100 °C, controlling tip temperature by continuous intraelectrode saline infusion could permit generation of larger lesion. (1) Two dogs randomly received either standard or cooled tip RF ablation at 4 to 6 separate LV sites. Power output of 30 W was delivered via modified 7 Fr deflectable catheter with 4 mm tip for up to 120 sec or until impedance rise occurred. (2) Six dogs randomly received cooled tip RF ablation at power output of 20, 30, 40 W for 120 sec. (3) Three dogs randomly received cooled tip RF ablation using room temperature saline (21–25 °C) or chilled saline (1–4 °C) infusion.
Results: Overall, peak tip temperature was lower for cooled vs standard RF deliveries (97±17 °C vs. 42±8 °C). Lesion depth and volume were significantly larger for cooled burns. Lesion depth and volume and the incidence of abrupt impedance rise/popping did not differ between room temperature saline and chilled saline infusion. The catheter-tip temperature at the onset of popping and abrupt impedance rise was 54±5 °C(48–60 °C) and 59±10 °C(50–75 °C).
Conclusion: Cooled tip RF current delivery at high power is associated with increased myocardial lesion size which may facilitate successful ablation of ventricular tachycardia associated with acquired structural heart disease. Catheter-tip temperature should be maintained below 45 °C to prevent popping and abrupt impedance rise during RF energy delivery. 相似文献