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Kenjiro Kikuchi

Publications and source records attributed to Kenjiro Kikuchi.

At least 19 recordsLinked to original sources
PubMed2006

Magnesium attenuates isoproterenol-induced acute cardiac dysfunction and beta-adrenergic desensitization.

Sympathetic nervous activation is a crucial compensatory mechanism in heart failure. However, excess catecholamine may induce cardiac dysfunction and beta-adrenergic desensitization. Although magnesium is known to be a cardioprotective agent, its beneficial effects on acute cardiac dysfunction remain to be elucidated. We examined the effects of magnesium on left ventricular (LV) dysfunction induced by a large dose of isoproterenol in dogs. Sixteen anesthetized dogs underwent a continuous infusion of isoproterenol (1 micro g.kg(-1).min(-1)) with or without a magnesium infusion (1 mg.kg(-1).min(-1)). The dose response to small doses of isoproterenol (0.025-0.2 micro g.kg(-1).min(-1)) was tested hourly. A large dose of isoproterenol decreased LV systolic function, increased the time constant of LV isovolumic relaxation, and suppressed the dose response to small doses of isoproterenol in a time-dependent manner. Magnesium significantly attenuated isoproterenol-induced LV systolic and diastolic dysfunction and preserved the dose response to isoproterenol. Serum-ionized calcium significantly decreased with a large dose of isoproterenol but was fully maintained at baseline level with magnesium. A large dose of isoproterenol increased serum lipid peroxide levels and serological markers of myocardial damage, which were significantly suppressed by magnesium. In conclusion, magnesium significantly attenuated excess isoproterenol-induced acute cardiac dysfunction and beta-adrenergic desensitization.

Animals↗
PubMed2006

An oral adsorbent, AST-120, suppresses oxidative stress in uremic rats.

BACKGROUND: The production of reactive oxygen species (ROS) has been suggested to play an important role in the progression of chronic kidney disease (CKD). An oral adsorbent, AST-120, removes uremic toxins such as indoxyl sulfate (IS) and delays the progression of CKD, but the effect on ROS production is unknown. The present study aimed to determine whether AST-120 reduces oxidative stress in uremic rat kidneys using markers of ROS production such as acrolein and 8-hydroxy-2'-deoxyguanosine (8-OHdG). METHODS: Daily administration of AST-120 was started 6 weeks after 5/6 nephrectomy and continued for 18 weeks. The changes in metabolic data, serum and urine IS levels, urinary excretion of markers of oxidative stress, and renal histological findings were investigated in uremic rats with or without AST-120 treatment. RESULTS: In parallel with the increase in serum and urine IS, the serum creatinine, urinary protein and acrolein levels started to increase at 6 weeks, but urinary 8-OHdG remained unchanged and significantly increased at 18 weeks in uremic rats. AST-120 markedly and significantly attenuated increases in uremic toxins and oxidative stress levels as well as the histological changes in glomerular sclerosis, interstitial fibrosis, and the tubular staining of 8-OHdG. CONCLUSION: AST-120 suppressed the progression of CKD, at least in part, via attenuation of oxidative stress induced by uremic toxin.

8-Hydroxy-2'-Deoxyguanosine↗
PubMed2006

Treatment of Japanese restless legs syndrome patients with cabergoline: an open clinical preliminary trial.

OBJECTIVE: To determine the effective dose of cabergoline in Japanese patients with restless legs syndrome (RLS). METHODS: Six cases of idiopathic RLS and three of RLS with Parkinson disease (PD) participated in an open clinical preliminary trial. All cases were diagnosed based on the clinical criteria of the International RLS Study Group. Three RLS cases (1.3%) were detected out of 229 consecutive cases with PD. RLS severity was evaluated with International RLS Study Group (IRLSSG) Rating Scale Version 2.2 before and one year after the treatment with cabergoline. RESULTS: For 6 idiopathic RLS patients, the IRLSSG questionnaire scores improved from 25.5+/-3.7 to 10.7+/-8.9 (p=0.028, Wilcoxon test) with 1 mg of daily cabergoline at the endpoint. For 3 RLS cases with PD, the score was 21.7+/-3.7 before the treatment, and RLS symptoms completely disappeared with 1 mg of cabergoline. One of RLS cases with PD required additional cabergoline later because of parkinsonism. No adverse event with cabergoline was reported in this study. CONCLUSION: One mg of daily cabergoline is effective in some Japanese patients of RLS.

Aged↗
PubMed2006

Edaravone diminishes free radicals from circulating neutrophils in patients with ischemic brain attack.

OBJECTIVE: Treatment with a free radical scavenger could be a new option for ischemic brain attack, however, little is known about the alteration of oxidative stress markers induced by edaravone, a novel free radical scavenger, in human ischemic brain attack. METHODS: We investigated the effects of edaravone on the oxidative stress markers in patients with ischemic brain attack. Twenty-one patients with ischemic brain attack and 19 controls were enrolled in this study. Blood samples were obtained just before and soon after the first administration of edaravone (30 mg) or ozagrel (40 mg). Intracellular reactive oxygen species of neutrophils were measured using 6-carboxy-2', 7'-dichlorodihydrofluorescin diacetate and a fluorescence-activated cell sorter. Superoxide from neutrophils, induced by phorbol myristate acetate (PMA), was determined by luminol-amplified chemiluminescence assay. RESULTS: Treatment with 30 mg of edaravone significantly decreased the intracellular reactive oxygen species (ROS) of neutrophils (Wilcoxon test, p=0.0001) and PMA-induced superoxide produced by neutrophils (Wilcoxon test, p=0.001). Ozagrel did not alter the intracellular ROS or superoxide production of neutrophils. CONCLUSION: Reduction of intracellular ROS and suppression of superoxide production in neutrophils provide a potential explanation for the clinical efficacy of edaravone in patients with ischemic brain attack.

Aged↗
PubMed2006

Increased serum level of vascular endothelial growth factor in Mycobacterium avium complex infection.

OBJECTIVE: Pulmonary infection caused by Mycobacterium avium complex (MAC) is one of the granulomatous diseases which are associated with the expression of vascular endothelial growth factor (VEGF). The aim of the present study was to clarify the association of VEGF with the pathogenesis of MAC infection. METHODOLOGY: The serum VEGF levels in 46 patients with pulmonary MAC infection were compared with those in 16 normal control subjects. Pulmonary lesions were evaluated using chest CT. In 20 patients, after treatment, serum VEGF levels were measured and chest CT performed again to evaluate pulmonary response to treatment. RESULTS: Infected patients had higher serum VEGF levels than controls (435.2 +/- 29.1 vs. 167.0 +/- 10.6 pg/mL, P < 0.0001), and serum VEGF level correlated with the extent of disease. The serum VEGF levels in 14 patients who underwent treatment and exhibited an improvement in their pulmonary lesions decreased significantly compared with the results pretreatment (509.0 +/- 60.7 vs. 303.6 +/- 65.3 pg/mL, P = 0.0092). In infected patients, alveolar macrophages, epithelioid cells and multinucleated giant cells exhibited VEGF overexpression on immunohistochemical staining. CONCLUSIONS: This study suggests that VEGF may be associated with the pathogenesis of pulmonary MAC infection. Additionally, serum VEGF levels may be a useful surrogate marker for evaluating the extent of disease and of the response to treatment.

Adult↗
PubMed2006

An overview of regular dialysis treatment in Japan (as of 31 December 2004).

A statistical survey of 3932 nationwide hemodialysis (hereafter, dialysis) facilities was carried out at the end of 2004, and 3882 facilities (98.73%) responded. The population undergoing dialysis at the end of 2004 was 248 166, an increase of 10 456 patients (4.4%) from that at the end of 2003. The number of dialysis patients per million people was 1943.5. The crude death rate of dialysis patients from the end of 2003 to the end of 2004 was 9.4%. The mean age of patients who underwent dialysis in 2004 was 65.8 years, and that of the total dialysis population was 63.3 years. The percentage distribution of patients who underwent dialysis according to a newly underlying disease showed that 41.3% of patients had diabetic nephropathy and 28.1% had chronic glomerulonephritis. The frequency of calcium carbonate use for dialysis patients was 75.1% and that of sevelamer hydrochloride use was 26.2%. The frequency of sevelamer hydrochloride use does not necessarily have a strong correlation with the dose of calcium carbonate. Patients who received high doses of sevelamer hydrochloride tended to have a low concentration of arterial blood HCO(3-). Approximately 15% of dialysis patients used an intravenous vitamin D preparation, generally maxacalcitol. The longer the patients had been on dialysis, the higher the frequency of use of an intravenous vitamin D preparation. When the concentration of serum intact parathyroid hormone (PTH) was more than 200 pg/mL, the frequency of use of an orally administered vitamin D preparation decreased; but that of intravenous vitamin D preparation increased. The percentage of dialysis patients who received percutaneous ethanol injection therapy (PEIT) was 1.4%. The percentage was more than 50% in the patients who had been on dialysis for more than 10 years. The percentage of patients who received PEIT again was 35.0%. The percentage of patients who had been on hemodialysis for more than 10 years and received PEIT again was more than 50%.

Adolescent↗
PubMed2006

[Takotsubo-like left ventricular dysfunction with delayed recovery of left ventricular shape: a case report].

A 70-year-old woman was admitted to our hospital because of left ventricular dysfunction, which was observed after permanent pacemaker implantation in another hospital. The left ventricular dysfunction was apical ballooning. Left ventriculography demonstrated takotsubo-like shape. However, the dysfunction did not improve immediately with medical treatment. In this case, 75% stenosis was observed in the left anterior descending artery. We suppose that this lesion corresponded to the delayed recovery of the dysfunction and performed coronary intervention. The takotsubo-like shape improved gradually for about 1 year. Whether the coronary intervention was effective for the recovery of the dysfunction is unclear, this clinical course was interesting in evaluating the delayed recovery of takotsubo-like left ventricular dysfunction.

Aged↗
PubMed2006

[Homocysteine].

Explore the source record for details and available documents.

Animals↗
PubMed2005

Hyperinsulinemia is an independent predictor for complex atherosclerotic lesion of thoracic aorta in non-diabetic patients.

OBJECTIVE: Hyperinsulinemia is a well known risk factor for cardiovascular event. However, it is not known whether hyperinsulinemia facilitates atherosclerotic complex lesions of aorta in non-diabetic patients. We investigated whether hyperinsulinemia is an independent marker of severity of atherosclerosis in thoracic aorta of non-diabetic patients using multiplane transesophageal echocardiography (TEE). RESEARCH DESIGN AND METHODS: Non-diabetic 90 patients with cardiovascular disease underwent TEE, and were analyzed for plasma insulin levels of oral glucose tolerance test, conventional atherosclerotic risk factors and coronary angiographic features. RESULTS: Thoracic aortic plaques were detected in 84 patients (93%). The complex atherosclerotic lesions were observed in 35 (39%) patients, most frequently at the part of aortic arch (p<0.005), showing the greatest atheroma score in thoracic aorta (p<0.05). Univariate analysis showed age, male gender, smoking, coronary artery disease, HDL-cholesterol, insulin levels in glucose tolerance test and homeostasis model assessment insulin resistance index (HOMA index) were found to be significant predictors of complex atherosclerotic lesions. Multivariate regression analysis revealed that HOMA index was an independent predictor of complex atherosclerotic lesions (odds ratio 1.93, p=0.006). There was a significant positive correlation between HOMA index and the atheroma score of thoracic aorta (p<0.001). CONCLUSIONS: Hyperinsulinemia is an independent predictor of complex atherosclerotic lesions detected by TEE in the thoracic aorta of non-diabetic patients.

Aged↗
PubMed2005

Tachycardia-induced myocardial ischemia and diastolic dysfunction potentiate secretion of ANP, not BNP, in hypertrophic cardiomyopathy.

The aim of this study was to investigate what factor determines tachycardia-induced secretion of atrial and brain natriuretic peptides (ANP and BNP, respectively) in patients with hypertrophic cardiomyopathy (HCM). HCM patients with normal left ventricular (LV) systolic function and intact coronary artery (n = 22) underwent rapid atrial pacing test. The cardiac secretion of ANP and BNP and the lactate extraction ratio (LER) were evaluated by using blood samples from the coronary sinus and aorta. LV end-diastolic pressure (LVEDP) and the time constant of LV relaxation of tau were measured by a catheter-tip transducer. These parameters were compared with normal controls (n = 8). HCM patients were divided into obstructive (HOCM) and nonobstructive (HNCM) groups. The cardiac secretion of ANP was significantly increased by rapid pacing in HOCM from 384 +/- 101 to 1,268 +/- 334 pg/ml (P < 0.05); however, it was not significant in control and HNCM groups. In contrast, the cardiac secretion of BNP was fairly constant and rather significantly decreased in HCM (P < 0.01). The cardiac ANP secretion was significantly correlated with changes in LER (r = -0.57, P < 0.01) and tau (r = 0.73, P < 0.001) in HCM patients. Tachycardia potentiates the cardiac secretion of ANP, not BNP, in patients with HCM, particularly when it induces myocardial ischemia and LV diastolic dysfunction.

Atrial Natriuretic Factor↗
PubMed2005

Ischemic preconditioning enhances scavenging activity of reactive oxygen species and diminishes transmural difference of infarct size.

Reactive oxygen species (ROS) enhance myocardial ischemia-reperfusion (I/R) injury. Ischemic preconditioning (PC) provides potent cardioprotective effects in I/R. However, it has not been elucidated whether PC diminishes ROS stress in I/R and whether PC protects the myocardium from ROS stress transmurally and homogeneously. Isolated rabbit hearts perfused with Krebs-Henseleit buffer underwent 30 min of ischemia and 60 min of reperfusion. Hemodynamic changes and myocardial damage extent were analyzed in four groups. The control group underwent I/R alone. The H2O2 group underwent I/R with H2O2 infusion (50 microM) in the first minute of reperfusion to enhance oxidative stress. The PC and H2O2+PC groups underwent 5 min of PC before control and H2O2 protocols, respectively. Extracted myocardial DNA was analyzed for 8-hydroxydeoxyguanosine (8-OHdG), an indicator of oxidative DNA damage, with the use of the HPLC-electrochemical detection method. Glutathione peroxidase (GPX) activity and the reduced form of GSH were measured by spectrophotometric assays. The myocardial infarct size was significantly reduced in the PC group (19 +/- 2%) compared with the control group (37 +/- 4%; P < 0.05), particularly in the subendocardium. H2O2 transmurally increased the infarct size by 59 +/- 4% (P < 0.05), which was significantly diminished in the H2O2+PC group (31 +/- 4%; P < 0.01). The GSH levels, but not GPX activity, were well preserved transmurally in protocols with PC. The 8-OHdG levels were significantly decreased in PC and were significantly enhanced in H2O2 (P < 0.01). These changes in oxidative DNA damage were effectively diminished by PC. In conclusion, PC enhanced the scavenging activity of GSH against ROS transmurally, reduced myocardial damage, particularly in the subendocardium, and diminished the transmural difference in myocardial infarct size.

8-Hydroxy-2'-Deoxyguanosine↗
PubMed2005

Doxapram stimulates the carotid body via a different mechanism than hypoxic chemotransduction.

To determine if doxapram stimulates the carotid body through the same mechanism as hypoxia, we compared the effects of doxapram and hypoxia on isolated-perfused carotid bodies in rabbits. Doxapram stimulated the carotid body in a dose-dependent manner. In Ca(2+)-free solution, neither doxapram nor hypoxia stimulated the carotid body. Although, doxapram had an additive effect on the carotid body chemosensory response to hypercapnia, a synergistic effect was not observed. Also, we investigated the various K(+) channel activators on the response to doxapram and hypoxia: pinacidil and levcromakalim as ATP-sensitive K(+) channel activators; NS-1619 as a Ca(2+)-sensitive K(+) channel activator; and halothane as a TASK-like background K(+) channel activator. The hypoxic response was partially reduced by halothane only, while pinacidil, levcromakalim and NS-1619 had no effect. Interestingly, the effect of doxapram was partially inhibited by NS-1619. Neither pinacidil nor levcromakalim affected the stimulatory effect of doxapram. We conclude that doxapram stimulates the carotid body via a different mechanism than hypoxic chemotransduction.

Anesthetics, Inhalation↗
PubMed2005

Multiple and recurrent systemic thrombotic events associated with congenital anomaly of inferior vena cava.

We describe a case of a 67-year-old woman with a history of cerebral infarction and pulmonary embolism that presented with chest pain. Subsequent evaluation resulted in a diagnosis of acute myocardial infarction and occult DVT, and imaging revealed a rare congenital absence of the infra-renal portion of the inferior vena cava, with lower extremity venous drainage diverted via an ascending lumbar vein. Associations between congenital absence of the inferior vena cava and thrombosis are discussed.

Aged↗
PubMed2005

Controlled-release nifedipine and candesartan low-dose combination therapy in patients with essential hypertension: the NICE Combi (Nifedipine and Candesartan Combination) Study.

OBJECTIVE: To compare the clinical efficacy of low-dose controlled-release (CR) nifedipine (20 mg/day) plus candesartan (8 mg/day) combination therapy with that of up-titrated candesartan (12 mg/day) monotherapy. DESIGN: Randomized, double-blind study. SETTING: Outpatient study. PATIENTS AND PARTICIPANTS: Patients with essential hypertension, who did not achieve their target blood pressure with baseline treatment of candesartan 8 mg/day for 8 weeks. MAIN OUTCOME MEASURES: Blood pressure, pulse pressure, urinary microalbumin excretion. RESULTS: Blood pressure was significantly reduced in both groups (P < 0.05), but the reduction was significantly greater in the combination therapy group (12.1 +/- 1.4/8.7 +/- 0.9 mmHg) than in the up-titrated monotherapy group (4.1 +/- 1.4/4.6 +/- 0.9 mmHg) (P < 0.0001). The reduction in pulse pressure was significantly greater in the combination therapy group (3.3 +/- 1.2 mmHg) than in the up-titrated monotherapy group (0.7 +/- 1.2 mmHg) (P = 0.0031). Urinary microalbumin excretion decreased significantly in the combination therapy group (from 61.9 to 40.5 mg/g creatinine; P < 0.05), but not in the up-titrated monotherapy group. CONCLUSIONS: These findings suggest that the low-dose combination therapy of nifedipine CR and candesartan is superior to the up-titrated monotherapy of candesartan in terms of blood pressure control and renal protection in patients with essential hypertension.

Adolescent↗