[Cervical aortic arch complicated with thoracic aortic aneurysms that occurred two times].
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Aorta, Thoracic↗
Biomedical subjects
Nobuhisa Hagiwara
Publications and source records attributed to Nobuhisa Hagiwara.
Levosimendan increases L-type Ca(2+) current via phosphodiesterase-3 inhibition in human cardiac myocytes.
To evaluate the potency of levosimendan, a newly developed cardiotonic agent, as a phosphodiesterase-3 inhibitor, we examined its effects on the L-type Ca(2+) current (I(Ca,L)) in single human atrial cells using the whole-cell voltage-clamp method. Levosimendan significantly increased I(Ca,L) in a concentration-dependent manner (E(max), 139.0 +/- 1.8%; EC(50), 54 +/- 3.6 nM). The increase in I(Ca,L) induced by 1 microM levosimendan was significantly greater in human atrial cells (136.7 +/- 11.0%, n=8) than in rabbit atrial cells (23.5 +/- 3.5%, n=6) (depolarization to +10 mV in each case). In rat atrial and ventricular cells, I(Ca,L) was unaffected by 1-10 microM levosimendan. These results indicate that the selective phosphodiesterase-3 inhibitor levosimendan increases cardiac-cell I(Ca,L) significantly more strongly in human than in rabbit and rat. It seems likely that the positive inotropic effect of levosimendan on the human myocardium depends on an increase in I(Ca,L) that is modulated by adenosine 3'5'-cyclic monophosphate (cAMP)-dependent phosphorylation.
1-Methyl-3-isobutylxanthine↗
Direct in vivo evidence of a vascular statin: a single dose of cerivastatin rapidly increases vascular endothelial responsiveness in healthy normocholesterolaemic subjects.
AIMS: HMG-CoA reductase inhibitors (statins) have been demonstrated to have in vitro vascular effects. The aim of this study was to determine whether statins actually have in vivo vascular effects independent of their cholesterol-lowering effect. METHODS: We investigated the effect of a single dose of cerivastatin on vascular endothelial function by measuring flow-mediated dilatation of the brachial artery on ultrasound in 30 healthy volunteers with normal serum cholesterol concentrations. They were randomized to either placebo group (n = 15) or cerivastatin group (n = 15), and flow-mediated dilatation and endothelium-dependent dilatation were evaluated at before and 1 h, 3 h, 6 h, and 12 h after administration of placebo or cerivastatin. RESULTS: There were no differences in total cholesterol, LDL cholesterol, HDL cholesterol, triglycerides, malondialdehyde-LDL, and high-sensitivity C-reactive protein before and after administration of placebo or cerivastatin. Cerivastatin significantly increased flow-mediated dilatation at 3 h (P < 0.001), and this increase rapidly returned to the baseline level 6 h after administration. Endothelium--independent dilatation of brachial artery was not altered. CONCLUSIONS: A single dose of cerivastatin increased vascular endothelial responsiveness. Our data suggest that cerivastatin has a direct effect on the blood vessels that is independent of its lipid-lowering effect, and thus can be considered as a vascular statin.
Adult↗
A 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor, cerivastatin, suppresses production of matrix metalloproteinase-9 in human abdominal aortic aneurysm wall.
AIM: Abdominal aortic aneurysm (AAA) is a common vascular degenerative disease. AAA wall contains inflammatory cells that produce matrix metalloproteinases (MMPs) that probably contribute to elastolysis and remodeling of the aneurysm. 3-Hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (statins) have been shown to reduce the expression of various molecules (including MMPs) independently of their cholesterol-lowering effect. The aims of this study are to investigate whether statins could modulate the biology of AAA wall and have a potential therapeutic value against AAAs. METHODS: We performed immunohistochemical analysis, evaluated MMP-9 production in the aortic wall from patients with infrarenal AAA (n = 10) and control patients with aortoiliac occlusive disease (n = 8), and examined the effect of cerivastatin on MMP-9 production in the AAA wall with organ culture. RESULTS: Neutrophils and macrophages were the cellular sources of MMP-9 in the AAA wall. The tissue concentrations of both total and active MMP-9 were significantly higher in tissues from AAA walls than in control aortic walls. Cerivastatin (0.001 to 0.1 micromol/L) significantly reduced the tissue levels of both total and active MMP-9 in a concentration-dependent manner (P <.001), and the production of tissue inhibitor of MMP-1 was unaffected. Cerivastatin neither reduced the number of infiltrating neutrophils and macrophages nor enhanced apoptosis of those cells, as evaluated with terminal transferase-mediated deoxyurisine triphosphate nick end labeling. CONCLUSION: These results suggest that cerivastatin can directly modulate the biology of the AAA wall and suppress MMP-9 production in the AAA wall by inhibiting the activation of neutrophils and macrophages, indicating that statin therapy could be useful for the prevention or treatment of AAA.
Aorta, Abdominal↗
Effects of NIP-141 on K currents in human atrial myocytes.
A novel benzopyran derivative, NIP-141, effectively terminates experimental atrial fibrillation in canine hearts by prolonging atrial refractoriness. However, the effects of this drug on human atrial myocytes are unknown. This experiment evaluated the effects of NIP-141 on K currents in isolated human atrial myocytes using a whole-cell voltage-clamp method. NIP-141 inhibited the transient outward current (I(to)) and the ultra-rapid delayed rectifier K current (I(Kur)), each in a dose-dependent manner, with half-maximal inhibition concentrations of 16.3 microM and 5.3 microM, respectively (n = 5). NIP-141 inhibited both K currents in a voltage- and use-independent fashion, and it preferentially blocked them in the open state and dissociated rapidly from the channel. Because both K currents contribute significantly to the repolarization of the atrial action potential, these findings suggest that NIP-141 may terminate atrial fibrillation by prolonging action potential duration.
Action Potentials↗
Effect of low-dose amiodarone on atrial fibrillation or flutter in Japanese patients with heart failure.
The efficacy and safety of amiodarone in the management of atrial fibrillation (AF) or flutter in 108 Japanese patients with heart failure was retrospectively examined. Thirty-four (41%) of the 82 patients who were in sinus rhythm after 1 month of amiodarone administration had their first recurrence, 70% of cases occurring within 1 year of initiation. The cumulative rates of maintenance of sinus rhythm were 0.68, 0.55, and 0.47 at 1, 3, and 5 years, respectively. Amiodarone was more effective in maintaining sinus rhythm in patients with paroxysmal AF or flutter than in those with the persistent form (p<0.05). The cumulative rates for cases that remained in permanent AF were 0.04, 0.11, and 0.14 at 1, 3, and 5 years, respectively. Apart from suppressing AF, the mean heart rate during Holter monitoring was significantly decreased with amiodarone therapy in cases of permanent AF. Adverse effects requiring the discontinuation of amiodarone therapy occurred in 16% of patients. Low-dose amiodarone therapy may prevent AF or flutter in Japanese patients with heart failure.
Amiodarone↗
Antiarrhythmic effect of nifekalant on atrial tachyarrhythmia in four patients with severe heart failure.
OBJECTIVES: Nifekalant is a class III antiarrhythmic drug, which prolongs the refractory period of the atrial and ventricular myocardium, without negative inotropic action. Intravenous nifekalant was administered in four patients with atrial tachyarrhythmia and severe heart failure to terminate or prevent atrial tachyarrhythmia. METHODS AND RESULTS: Two of three episodes of atrial tachyarrhythmia were terminated by intravenous nifekalant (0.22 to 0.30 mg/kg) administration. Continuous intravenous infusion of nifekalant (0.15 to 0.40 mg/kg/hr) during six episodes to maintain the sinus rhythm, prevented recurrence of atrial tachyarrhythmia in five episodes in which prolongation of the QTc interval was observed to more than 450 msec. None of the patients showed worsening of the hemodynamics during treatment. One patient developed polymorphic ventricular tachycardia, which deteriorated into ventricular fibrillation. CONCLUSIONS: Nifekalant may be effective for treating atrial tachyarrhythmia in patients with severe heart failure. Further clinical studies are needed to confirm these findings.
Adult↗
[Cardiac pacemaker].
Many of the indications for cardiac pacing have evolved based on experience without the benefit of comparative, randomized clinical trials. The committee of the American College of Cardiology(ACC) and the American Heart Association(AHA) have jointly engaged in the production of the guidelines for implantation of cardiac pacemakers and antiarrhythmic devices in 1998. This guideline updates the previous versions published in 1984 and 1991. The recommendations listed in this guideline are, whenever possible, evidence based. The decisions regarding the need for a pacemaker are importantly influenced by the presence or absence of symptoms directly attributable to bradycardia. According to these new guidelines, we described the indications for permanent pacing, the choice of pacemaker generator and pacemaker follow-up in this issue.
Arrhythmia, Sinus↗
An angiotensin-converting enzyme inhibitor, not an angiotensin II type-1 receptor blocker, prevents beta-aminopropionitrile monofumarate-induced aortic dissection in rats.
OBJECTIVE: Cystic medial degeneration (CMD) is a histologic abnormality that is common in aortic diseases such as aortic dilation, aneurysm, or dissection. Although little is known about the mechanism underlying CMD, we have previously demonstrated that angiotensin II signaling via angiotensin II type 2 receptor (AT2R) plays a central role in apoptosis of vascular smooth muscle cells (VSMCs) occurring in CMD associated with Marfan syndrome. The aim of this study is to elucidate the role of angiotensin II signaling in THE pathogenesis of aortic diseases associated with CMD. METHOD: We investigated the effects of angiotensin-converting enzyme inhibitor (ACEI), temocapril (n = 15), angiotensin II receptor type-1 (AT1R) blocker, CS-866 (n = 15), and vehicle control (n = 17) on 0.25% beta-aminopropionitrile monofumarate (BAPN)-induced aortic dissection and histopathologic findings in a rat model. RESULTS: Temocapril significantly prevented aortic dissection (P <.05), CMD (P <.01), and VSMC apoptosis (P <.01) compared with vehicle control in BAPN-fed rats. However, CS-866 did not show any preventive effect. Reversed transcriptase-polymerase chain reaction demonstrated that expression of both AT1R and AT2R was detected in control rat aortas, and that AT2R expression was significantly upregulated in the aortas of BAPN-fed rats (P <.01). Blood pressure was significantly and equally lowered in both temocapril and CS-866 groups compared with control. CONCLUSIONS: Differential expression of angiotensin II receptors and AT2R signaling are involved in the pathogenesis of CMD and aortic dissection in BAPN-fed rats. ACEIs might be of clinical value for the prevention and treatment of aortic diseases related to CMD.
Aminopropionitrile↗