K Arakawa

St.Mary's Hospital (Fukuoka - Japan), Hukuoka, Fukuoka, Japan

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Publications (16)50.82 Total impact

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    ABSTRACT: A double-blind, placebo-controlled study was conducted to evaluate the efficacy, safety, and utility of TSUMURA Orengedokuto Extract Granules for Ethical Use (TJ-15) as a treatment for the accessory symptoms of hypertension. Two capsules of the study drug were administered orally 3 times daily (i.e., before meals) for 8 weeks. Among 265 patients enrolled in the study, 134 were assigned to the TJ-15 group and 131 were assigned to the placebo group, of whom 204 patients (103 in the TJ-15 group and 101 in the placebo group) were included in the efficacy and utility analyze and 251 patients (128 in the TJ-15 group and 123 in the placebo group) were included in the safety analysis. Efficacy was significantly higher in the TJ-15 group based on the total score for the accessory symptoms of hypertensions which was the primary efficacy endpoint (Wilcoxon's rank sum test, p=0.013). When each accessory symptom of hypertension was assessed separately, efficacy was higher for hot flushes and facial suffusion in the TJ-15 group (Wilcoxon's rank sum test, p=0.034, and 0.022, respectively). There were no significant differences between the TJ-15 and the placebo groups with respect to the decrease of blood pressure or the antihypertensive effect. There was also no significant difference between the two groups with regard to the overall safety rating. The utility rating was significantly higher in the TJ-15 group than in the placebo group (Wilcoxon's rank sum test, p=0.016). In conclusion, TJ-15 was superior to placebo with respect to efficacy, safety, and utility for the treatment of accessory symptoms of hypertension.
    Phytomedicine 02/2006; 13(1-2):1-10. · 2.97 Impact Factor
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    ABSTRACT: Background. Although glucocorticoids elicit systemic hypertension, they are also demonstrated to cause marked increases in renal blood flow. The mechanism of this alteration, however, remains undetermined. Methods. Dogs were treated with dexamethasone (DEX) for 7 days, and renal, as well as systemic hemodynamic, responses to DEX were assessed. In addition, the role of intrarenal angiotensin (ANG) II in mediating the glucocorticoid-induced renal vasodilation was examined in conscious unrestrained dogs. Results. Seven-day treatment with DEX caused prominent increases in mean arterial pressure (MAP; from 80 ± 2 to 98 ± 5 mmHg) and in renal plasma flow (RPF; from 142 ± 4 to 191 ± 7 ml/min), with decreases in renal vascular resistance [RVR; from 0.26 ± 0.01 to 0.22 ± 0.01 mmHg/(ml/min)] and in the filtration fraction (FF; from 0.24 ± 0.01 to 0.20 ± 0.01). DEX treatment did not alter plasma ANG II levels, but enhanced candesartan-induced reduction in MAP. In contrast, the candesartan-induced increase in RPF (19 ± 2% increase) was completely abolished by DEX. DEX treatment markedly reduced renal tissue ANG II content (from 1.09 ± 0.07 to 0.71 ± 0.04 pg/mg tissue), which paralleled the response of renal tissue angiotensin-converting enzyme (ACE) activity (−20 ± 4%). Finally, intravenous ANG II administration caused a greater reduction in RPF during the DEX treatment period (−17 ± 2% vs −11 ± 1% in the control period). Conclusions. Glucocorticoids cause hypertension, but they also cause a paradoxical decrease in RVR and increase in RPF. The renal responses to candesartan and exogenous ANG II during DEX treatment suggest that the attenuation of intrarenal ANG-mediated vascular tone plays an important role in the altered renal hemodynamics. The decreased ANG tone is likely caused by reduced ANG II formation, resulting in part from suppressed ACE activity, but not from decreased sensitivity to ANG II.
    Clinical and Experimental Nephrology 08/2001; 5(3):186-192. · 1.25 Impact Factor
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    ABSTRACT: The present study examined the role of intrarenal bradykinin in angiotensin-converting enzyme inhibitor (ACEI)-induced dilation of renal afferent (AFF) and efferent arterioles (EFF) in vivo, and further evaluated whether ACEI-stimulated bradykinin activity differed in superficial (SP) and juxtamedullary nephrons (JM). Arterioles of canine kidneys were visualized with an intravital charge-coupled device camera microscope. E4177 (an angiotensin receptor antagonist, 30 microg/kg) dilated AFF and EFF in SP (15 +/- 3% and 19 +/- 5%) and JM (15 +/- 3% and 18 +/- 4%). Subsequently, cilazaprilat (30 microg/kg) caused further dilation of both AFF (29 +/- 4%) and EFF (36 +/- 4%) in JM, whereas in SP it dilated only EFF (29 +/-3%). Similarly, in the presence of E4177, cilazaprilat caused further increases in sodium excretion. This cilazaprilat-induced vasodilation and natriuresis was abolished by a bradykinin antagonist (N(alpha)-adamantaneacetyl-D-Arg-[Hyp3,Thi5,8,D-Phe7]b radykinin). In parallel with these results, cilazaprilat increased renal bradykinin content, more greatly in the medulla than in the cortex (5.7 +/- 0.4 versus 4.6 +/- 0.1 ng/g). Similarly, cilazaprilat elicited greater bradykinin-dependent increases of nitrite/nitrate in the medulla. In conclusion, zonal heterogeneity in renal bradykinin/nitric oxide levels and segmental differences in reactivity to bradykinin contribute to the diverse responsiveness of renal AFF and EFF to ACEI. ACEI-enhanced kinin action would participate in the amelioration of glomerular hemodynamics and renal sodium excretion by ACEI.
    Journal of the American Society of Nephrology 12/1999; 10(11):2272-82. · 8.99 Impact Factor
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    ABSTRACT: To compare the incidence of cough between two angiotensin converting enzyme (ACE) inhibitors, imidapril and enalapril, comparative crossover study was performed in 489 patients (228 men and 261 females) with essential or renal parenchymal hypertension. Patients were randomly assigned to one of two treatment groups, a group receiving imidapril for 12 wk (Period I) followed by enalapril for 12 wk (Period II), and a group in which the order of drugs was reversed. The occurrence of cough during treatment was monitored by questionnaire in all cases. There were no differences in background characteristics between the two groups. The incidence of cough during Period I was 15.2% (32/210) in the group initially treated with imidapril (Group IE) and 38.6% (85/220) in the group initially treated with enalapril (Group EI), the difference being statistically significant (p < 0.001). During Period I, decrease in blood pressure was observed in 63.9% (115/180) of Group IE and 64.6% (115/178) of Group EI patients. In approximately half of the patients in Group EI who developed cough during Period I and in whom the treatment was subsequently switched to imidapril, cough subsequently disappeared. It was concluded that the incidence of cough was significantly less under imidapril than under enalapril treatment, while there was no difference in the antihypertensive effects of the two ACE inhibitors.
    Hypertension Research 10/1999; 22(3):197-202. · 2.79 Impact Factor
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    ABSTRACT: In conscious deoxycorticosterone acetate (DOCA) salt-hypertensive dogs, the angiotensin-converting enzyme (ACE) inhibitors captopril and imidaprilat significantly decreased mean arterial pressure (MAP) and significantly increased urine flow rate, effective renal plasma flow (ERPF), glomerular filtration rate, and urinary sodium excretion. However, the angiotensin type 1 (AT1) receptor antagonist losartan caused a significant increase only in urinary sodium excretion without significant changes in MAP, urine flow rate, ERPF, and glomerular filtration rate. Simultaneous infusion of a bradykinin receptor antagonist inhibited the ACE inhibitor-induced reduction in MAP and increase in ERPF. DOCA salt treatment markedly suppressed plasma angiotensin II (ANG II) concentration (P < 0.001), although it decreased renal ANG II content only slightly (P < 0.05). Comparison of the expression of renal AT1 receptor mRNA in control kidneys with that in DOCA salt-hypertensive kidneys revealed no significant change. These results suggest that, in low-renin hypertension, inhibition of the relatively maintained ANG II production in the kidney participates in the natriuretic action of ACE inhibitors. However, hypotensive and other renal effects are mainly due to the action of bradykinin.
    The American journal of physiology 02/1997; 272(2 Pt 2):H679-87. · 3.28 Impact Factor
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    ABSTRACT: Despite the development of non-ionic radiographic contrast media (CM), CM-induced nephropathy is a clinically important problem in patients with pre-existing renal insufficiency. We examined the effects of non-ionic CM (iohexol) on renal function in conscious dogs with and without renal insufficiency, and evaluated the effects of a non-selective (theophylline), an A1 selective (KW-3902), and an A2 selective adenosine antagonist (KF17837) on the renal responses to CM. In sham-operated group, iohexol (2 ml/kg/min for 3 min) increased effective renal plasma flow (ERPF) and glomerular filtration rate (GFR), whereas in renal insufficiency group (with subtotal nephrectomy), following transient increases in ERPF and GFR, CM markedly decreased ERPF (-46.5 +/- 6.7%) and GFR (-51.2 +/- 7.1%). In sham-operated group, theophylline and KF17837 markedly attenuated CM-induced increases in ERPF and GFR, while KW-3902 had no effects on CM-induced increases in ERPF or GFR. In renal insufficiency group, initial increases in ERPF and GFR were blunted by theophylline and KF17837. In contrast, the subsequent decreases in ERPF and GFR were attenuated by theophylline (% delta ERPF, -12.2 +/- 3.2% vs. -46.6 +/- 6.7%, P < 0.01; % delta GFR, 4.3 +/- 2.5% vs. -51.0 +/- 7.1%, P < 0.01), and were completely prevented by KW-3902 (% delta ERPF, 10.8 +/- 2.9%; % delta GFR, 23.8 +/- 4.4%), whereas KF17837 aggravated ERPF (-73.3 +/- 5.3%) and GFR (-78.4 +/- 5.3%). These data indicate that in normal renal function, iohexol elicits renal vasodilation by activating mainly the adenosine A2 receptors. In contrast, in impaired renal function, CM induces both A2 and A1 activation; the former is associated with the initial renal vasodilation, while the latter is responsible for the sustained aggravation of renal hemodynamics.
    Kidney International 05/1996; 49(5):1199-206. · 8.52 Impact Factor
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    ABSTRACT: The clinical efficacy and safety of bevantolol hydrochloride, a newly developed beta-blocker, used in combination with other types of antihypertensive agents, were evaluated in patients with severe hypertension by multicenter open-label trials. A total of 28 patients were studied at 20 medical centers. Four patients (14.3%) were excluded for some reasons, and the remaining 24 patients (22 outpatients and 2 inpatients) were analyzed. Following the initiation of therapy, blood pressure decreased from 181 +/- 15 (SD)/114 +/- 3 mmHg to 170 +/- 17/102 +/- 8 mmHg (p < 0.01) on the 14th day of the therapy and gradually lowered further thereafter. At the end of the trial (8th week), blood pressure was stabilized at the level of 160 +/- 14/96 +/- 10 mmHg. The antihypertensive efficacy rated by the changes in mean blood pressure was 79.2% (19/24). Pulse rate decreased slightly but significantly from 75 +/- 10 beats/min to 70 +/- 7 (p < 0.05) on the 14th day of the therapy and stabilized at the similar level thereafter. As abnormal laboratory data were detected in 3 patients and 1 patient complained of a mild headache, the safety ratio was 83.3% (20/24 patients). When the usefulness was assessed in terms of antihypertensive efficacy and safety profiles, bevantolol hydrochloride was considered useful in 75.0% of the patients studied. In conclusion, bevantolol hydrochloride, used in combination with other classes of antihypertensive agents, appears to be an excellent drug for the management of patients with severe hypertension.
    International journal of clinical pharmacology and therapeutics 05/1995; 33(4):240-5. · 1.20 Impact Factor
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    ABSTRACT: Rapid right ventricular pacing could induce congestive heart failure in conscious dogs with significant increase in plasma concentration of arginine vasopressin (AVP) (from 1.2 +/- 0.2 to 3.4 +/- 0.6 pg/ml). In this experimental model of heart failure, oral administration of the selective AVP V1 receptor antagonist OPC-21268 significantly increased cardiac output and improved renal function without significant changes in serum electrolytes and hormones. Oral administration of the selective AVP V2 receptor antagonist OPC-31260 induced marked water diuresis, which resulted in significant increases in serum sodium concentration, plasma renin activity, and plasma concentration of AVP, although it did not produce hemodynamic improvement. Combined administration of OPC-21268 and OPC-31260 showed supra-additive hemodynamic responses as well as additive renal and metabolic responses, i.e., it showed prolonged decrease in mean arterial pressure and profound increase in cardiac output. These results suggest that AVP plays a significant role in elevation of vascular tone through V1 receptors and plays a major role in retaining free water through V2 receptors in this model of heart failure. Furthermore, combined administration of V1 and V2 receptor antagonists could induce not only metabolic and hormonal responses but also more beneficial hemodynamic responses than those observed following treatment with V1 receptor antagonist alone.
    The American journal of physiology 01/1995; 267(6 Pt 2):H2245-54. · 3.28 Impact Factor
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    ABSTRACT: The goals of these preliminary studies were to evaluate the effects of a new angiotensin II receptor antagonist, TCV 116, on the daytime blood pressure profile in hospital inpatients with essential hypertension, and to evaluate the clinical efficacy and safety of this agent in outpatients with essential hypertension. In study 1, daytime blood pressure changes were studied in 28 inpatients with mild to moderate essential hypertension (systolic blood pressure > or = 150 mmHg, diastolic blood pressure > or = 90 mmHg). In study 2, 55 outpatients with essential hypertension (systolic blood pressure > or = 160 mmHg, diastolic blood pressure > or = 95 mmHg) were enrolled in a dose-finding study. In study 1, after a 1-week placebo run-in period, blood pressure and the pulse rate were measured every 2 h except at night. TCV 116 monotherapy was started at 1 mg/day and increased stepwise at 3- to 5-day intervals to 2, 4 and 8 mg/day until a predetermined reduction in blood pressure was achieved. The daytime profiles of blood pressure and the pulse rate were again monitored at the end of the treatment period. In study 2, after a 4-week placebo run-in period, TCV 116 alone was administered for 2 weeks at 1 mg/day. The dose was then increased to 2 mg/day and stepwise at 2-week intervals to 4 and 8 mg/day until a predetermined reduction in blood pressure was achieved. The total treatment period was 8-12 weeks. In study 1, a sufficient reduction in blood pressure was achieved in 19 of 28 patients (68%), with blood pressure significantly reduced at all measurement points, compared with the placebo run-in period. No differences were seen in the pulse rate. The only adverse reaction reported was a rash in one patient. In study 2, a sufficient reduction in blood pressure was achieved in 42 out of 55 patients (76%). The cumulative efficacy rate increased dose-dependently (15% at 1 mg/day, 38% at 2 mg/day, 60% at 4 mg/day and 76% at 8 mg/day). No differences were seen in the pulse rate. Adverse reactions were reported in three out of 55 patients (5.5%). No dry cough was reported by any of the patients. TCV 116, an angiotensin II receptor antagonist, has potential as an antihypertensive agent. A dose of 4-8 mg once per day appears to be appropriate for the treatment of patients with mild to moderate essential hypertension.
    Journal of hypertension. Supplement: official journal of the International Society of Hypertension 11/1994; 12(9):S35-8.
  • Current Therapeutic Research-clinical and Experimental - CURR THER RES. 01/1992; 52(1):113-123.
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    ABSTRACT: In an open clinical study, the efficacy and safety of carvedilol was investigated in 26 severely hypertensive patients controlled inadequately on a diuretic [diastolic blood pressure (DBP) greater than 120 mm Hg at first visit and greater than 110 mm Hg following more than 1 week administration of a diuretic]. Following diuretic treatment all patients were initially administered 5 mg of carvedilol once daily. The dose was gradually increased to 10 mg and 20 mg until DBP was reduced below 100 mm Hg or until it was reduced by at least 10 mm Hg. Antihypertensive activity of carvedilol (5 mg) was sufficient in only three cases, but after 4 weeks (inpatients) or 8 weeks (outpatients) administration of carvedilol (10 mg or 20 mg), DBP/systolic blood pressure was significantly reduced from 176 +/- 6/117 +/- 3 to 145 +/- 3/94 +/- 2 mm Hg (p less than 0.001) in all patients. Overall, a sufficient antihypertensive effect was observed in 80% of the patients. Heart rate was significantly decreased from 76 +/- 2 to 67 +/- 2 beats/min, but no patient experienced bradycardia. Carvedilol was generally well tolerated. These findings suggest that 10-20 mg of carvedilol once daily, in combination with a diuretic, is an effective and safe treatment for patients with severe hypertension.
    Journal of Cardiovascular Pharmacology 02/1991; 18 Suppl 4:S69-72. · 2.38 Impact Factor
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    ABSTRACT: Delapril, a new angiotensin converting enzyme (ACE) inhibitor discovered in the laboratory of Takeda Chemical Industries, Ltd., is the result of drug design based on the structure-activity relationships of ACE inhibitors. Delapril is an antihypertensive agent with a relatively long duration of action and no SH moiety in its structure. Following administration, it is converted into two active metabolites. Delapril effectively lowered blood pressure in 73% of 1,008 patients with hypertension during clinical trials in Japan. Efficacy rates were 73% for essential hypertension, 85% for renal hypertension, and 80% for renovascular hypertension. Excellent hypotensive response was observed in all age groups, from young to elderly patients. Side effects during administration of delapril, based on subjective evidence, were reported in 80 out of the 1,008 cases (7.9%). The main symptoms included orthostatic dizziness (1.7%), dizziness (1.3%), and nausea (1.1%). Dry cough, which has attracted attention in recent years as a side effect of ACE inhibitors, was reported at a low incidence of 1.1%. In a double-blind, controlled study in patients with mild to moderate essential hypertension in which captopril served as a positive control, delapril showed superior hypotensive effect and greater safety. Data derived from the Japan Study Group on Delapril indicate that this ACE inhibitor has excellent hypotensive effects and a high level of safety. It is suitable as a first-line drug in both monotherapy and combined therapy.
    American Journal of Hypertension 02/1991; 4(1 Pt 2):42S-45S. · 3.67 Impact Factor
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    ABSTRACT: In order to evaluate the usefulness of urapidil in the treatment of severe hypertension and in the long-term treatment of essential hypertension, two open multicentre studies were performed. In one study, 34 outpatients with diastolic blood pressure exceeding 105 mmHg following treatment with a combination of a diuretic and a sympatholytic or a diuretic and a [beta]-blocker were additionally given 15-60 mg urapidil twice a day for 8 weeks or more. The responder rate was 73.5%. The pulse rate did not change throughout. Side effects such as dizziness and malaise were observed in five patients (14.7%), but they were slight and did not require withdrawal of treatment. The other study included 95 outpatients with essential hypertension (World Health Organization stages I or II), 15-60 mg urapidil twice a day for 1 year or more in monotherapy (n = 48) or in combined therapy with a thiazide (n = 47). Under both therapies, diastolic blood pressure was reduced significantly at week 4, further reduced at week 12 and remained stable until week 52. Responder rates were 82.9% in monotherapy and 78.4% in combined therapy. Two patients (4.2%) taking monotherapy and six patients (12.8%) taking combined therapy were withdrawn due to inadequate blood pressure control or to side effects. These results indicate that urapidil is useful in severe and in long-term hypertension. (C) Lippincott-Raven Publishers.
    Journal of Hypertension 11/1988; 6. · 4.22 Impact Factor
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    ABSTRACT: This study was performed to find the optimal dose of carvedilol, in terms of efficacy and safety, in Japanese patients with mild to moderate essential hypertension. 134 patients with blood pressure greater than 160/95 mm Hg after a 4-week placebo run-in period were initially given carvedilol 5mg once daily. The dose was increased to 10 and 20mg at 4-weekly intervals if the target blood pressure was not achieved. The duration of treatment was 12 weeks. After 12 weeks' administration, the average blood pressure was significantly (p less than 0.001) reduced from 170/101 to 150/91 mm Hg. The hypotensive activity of carvedilol 5mg was mild, but sufficient hypotensive effect was observed in 65% of patients receiving up to 20 mg/day. No significant postural changes in blood pressure were observed. Although heart rate was significantly decreased (77 to 66 beats/min, p less than 0.001), no patient was judged to have bradycardia. Side effects occurred in 5.2% of patients. Carvedilol 10 to 20mg once daily is considered to be an effective and safe treatment for essential hypertension.
    Drugs 02/1988; 36 Suppl 6:75-81. · 4.13 Impact Factor
  • Current Opinion in Cardiology - CURR OPIN CARDIOL. 01/1988; 3.
  • Drugs 01/1988; 36:118-123. · 4.13 Impact Factor