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Anna Maruyama

Bio: Anna Maruyama is an academic researcher from Osaka University. The author has contributed to research in topics: Blood pressure & Angiotensin II. The author has an hindex of 8, co-authored 22 publications receiving 323 citations.

Papers
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Journal ArticleDOI
TL;DR: The blood pressure of patients with essential hypertension has a seasonal variation with higher pressures in the winter than in the summer, and an increased load of sodium presented to the kidney for excretion may be contributing factors in the rise in blood pressure in winter.
Abstract: We examined the role of dietary electrolytes and humoral factors in causing seasonal changes in blood pressure. Normal subjects had no seasonal difference in blood pressure, although urinary sodium and norepinephrine were significantly higher in winter than in summer. In patients with essential hypertension blood pressure, urinary sodium and norepinephrine excretion and plasma norepinephrine concentration were significantly higher in winter. Plasma renin activity, plasma and urinary aldosterone and urinary kallikrein excretion were not significantly different between the two seasons in both normal subjects and hypertensive patients. In conclusions, the blood pressure of patients with essential hypertension has a seasonal variation with higher pressures in the winter than in the summer. Increased sympathetic nervous activity and an increased load of sodium presented to the kidney for excretion may be contributing factors in the rise in blood pressure in winter in patients with essential hypertension.

167 citations

Journal ArticleDOI
TL;DR: It is concluded that another mechanism, such as enhancement of renal or local kinin‐prostaglandin system, as well as suppression of the renin‐angiotensin‐aldosterone system may be involved in the long‐term efficacy of captopril.
Abstract: Captopril was given alone and in combination with diuretics to 49 patients with hypertension for 1 to 12 mo. Within 2 mo blood pressure reduction correlated with pretreatment plasma renin activity and response to the infusion of angiotensin II antagonist, but these effects were not present at 4 mo. Plasma and urinary aldosterone were suppressed but serum converting enzyme activity, plasma bradykinin, kallikrein, and prostaglandins (E and F) were in the normal range throughout the study period. Indomethacin (150 mg/day) for 1 wk abolished the hypotensive effect of captopril. Despite sustained reduction of blood pressure, plasma catecholamines were not elevated and urinary catecholamines were suppressed in patients on captopril alone. It is concluded that another mechanism, such as enhancement of renal or local kinin-prostaglandin system, as well as suppression of the renin-angiotensin-aldosterone system may be involved in the long-term efficacy of captopril. Sympathetic activity may also be depressed and contribute to the hypotensive effect. Clinical Pharmacology and Therapeutics (1981) 30, 328–335; doi:10.1038/clpt.1981.168

28 citations

Journal ArticleDOI
TL;DR: The data show that an acute stimulation with furosemide and ambulation affects mainly the active form of plasma renin, and the effect of age on inactive renin in normal subjects may be different from that in patients with essential hypertension.
Abstract: The effect of age on the levels of active and trypsin-activatable inactive plasma renin was examined in 41 normal subjects and 54 patients with essential hypertension, during recumbency and after stimulation with furosemide and ambulation. Active renin levels in supine subjects and patients decreased with age. Inactive renin levels did not change with age in normal subjects, whereas in hypertensive patients they decreased with age. Following stimulation with furosemide and ambulation, the levels of active renin increased but the responsiveness to stimulus decreased with age in both groups. In contrast, inactive renin levels slightly increased after furosemide administration and ambulation, resulting in increased proportion of active to total renin. These data show that an acute stimulation with furosemide and ambulation affects mainly the active form of plasma renin, and the effect of age on inactive plasma renin in normal subjects may be different from that in patients with essential hypertension.

22 citations

Journal ArticleDOI
TL;DR: The age-related decrease of U(kal)V in normal subjects may be due to the reduced activity of the renin-angiotensin-aldosterone system, which is related to the pathogenesis or pathophysiology of essential hypertension.
Abstract: The effect of aging on urinary kallikrein excretion (UkalV) was investigated in 54 normal subjects, 11-88 yr old, and 37 patients with essential hypertension, 17-82 yr old. Urinary sodium, potassium, and aldosterone excretion (U(Ald)V) were also measured in these subjects. Urinary sodium and potassium excretion in both normal subjects and hypertensive patients did not significantly change with aging. In normal subjects, U(kal)V (r = 0.45; P less than 0.001) and U(Ald)V (r = 0.58; P less than 0.01) significantly decreased with increasing age. U(kal)V was positively correlated with U(Ald)V (r = 0.44; P less than 0.001). In contrast, the hypertensive patients had a significant decrease with age in U(Ald)V (r = -0.36; P less than 0.05), but no significant age-related change in U(kal)V. No significant correlation between U(kal)V and U(Ald)V was observed in the hypertensive patients. In individuals less than 60 yr old, there was no significant difference in U(kal)V values between normal subjects and hypertensive patients. Hypertensive patients more than 60 yr old excreted more urinary kallikrein than normal subjects of the same age group (P less than 0.05). In conclusion, the age-related decrease of U(kal)V in normal subjects may be due to the reduced activity of the renin-angiotensin-aldosterone system. It remains to be elucidated whether the absence of the age-related decrease in U(kal)V in hypertensive patients is related to the pathogenesis or pathophysiology of essential hypertension.

19 citations

Journal ArticleDOI
TL;DR: The angiotensin-aldosterone system in elderly essential hypertensive patients is suppressed and is presumably not responsible for their elevated blood pressures.
Abstract: 1. To characterize the renin-angiotensin-aldosterone system in elderly hypertensive patients, an angiotensin II antagonist, [Sar1,Ile8]angiotensin II, was infused into individuals 60 years old and older with and without hypertension. 2. After infusion of [Sar1,Ile8]angiotensin II in all of the elderly patients and subjects an agonistic pressor response was observed that was greater than in middle-aged hypertensive patients. 3. Pre-infusion plasma renin activity and plasma aldosterone concentration in hypertensive and normotensive elderly groups were suppressed in comparison with those in middle-aged hypertensive subjects. The increased agonistic effects of [Sar1,Ile8]angiotensin II infusion on blood pressure in the elderly are presumably due to their hyporeninaemia. 4. The angiotensin-aldosterone system in elderly essential hypertensive patients is suppressed and is presumably not responsible for their elevated blood pressures.

15 citations


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TL;DR: Ongoing studies will elucidate the effect of ACE inhibitor on cardiovascular mortality in essential hypertension, the role of ACE inhibitors in patients without ventricular dysfunction after myocardial infarction, and the roleof ACE inhibitors compared with newly available angiotensin AT1 receptor antagonists.
Abstract: ACE inhibitors have achieved widespread usage in the treatment of cardiovascular and renal disease. ACE inhibitors alter the balance between the vasoconstrictive, salt-retentive, and hypertrophic properties of angiotensin II (Ang II) and the vasodilatory and natriuretic properties of bradykinin and alter the metabolism of a number of other vasoactive substances. ACE inhibitors differ in the chemical structure of their active moieties, in potency, in bioavailability, in plasma half-life, in route of elimination, in their distribution and affinity for tissue-bound ACE, and in whether they are administered as prodrugs. Thus, the side effects of ACE inhibitors can be divided into those that are class specific and those that relate to specific agents. ACE inhibitors decrease systemic vascular resistance without increasing heart rate and promote natriuresis. They have proved effective in the treatment of hypertension, they decrease mortality in congestive heart failure and left ventricular dysfunction after myocardial infarction, and they delay the progression of diabetic nephropathy. Ongoing studies will elucidate the effect of ACE inhibitors on cardiovascular mortality in essential hypertension, the role of ACE inhibitors in patients without ventricular dysfunction after myocardial infarction, and the role of ACE inhibitors compared with newly available angiotensin AT1 receptor antagonists.

910 citations

Journal ArticleDOI
02 Oct 1982-BMJ
TL;DR: The seasonal variation in blood pressure was greater in older than in younger subjects and was highly significantly related to maximum and minimum daily air temperature measurements but not to rainfall.
Abstract: Blood pressure measurements recorded during the medical Research Council's treatment trial for mild hypertension have been analysed according to the calendar month in which the readings were made. For each age, sex, and treatment group systolic and diastolic pressures were higher in winter than in summer. The seasonal variation in blood pressure was greater in older than in younger subjects and was highly significantly related to maximum and minimum daily air temperature measurements but not to rainfall.

507 citations

Journal ArticleDOI
01 Dec 1980-Drugs
TL;DR: Captopril must be considered an exciting addition to the therapeutic armamentarium; it, and pharmacologically related compounds of the future, will continue to generate much interest as their final place in therapy becomes better defined through additional well designed studies and wider clinical experience.
Abstract: Captopril is the first orally active inhibitor of angiotensin-converting enzyme to become available. It has been studied primarily in hypertension. In mild to moderate essential hypertension captopril is about as effective as usual doses of hydrochlorothiazide or propranolol, about one-half of such patients needing the addition of a diuretic to achieve satisfactory control of blood pressure. In severe hypertension captopril plus a diuretic (and in some patients a beta-blocker) usually reduced blood pressure significantly more than could be achieved with 'standard triple therapy' in patients not responding adequately to such a regimen, and often resulted in an improved feeling of well-being in severely hypertensive patients previously receiving intensive multiple drug therapy. Indeed, at the present stage of the drug's development, patients not responding to or not tolerating 'traditional' antihypertensive therapy represent the most suitable candidates for captopril treatment. While captopril has been well tolerated in most patients, some troublesome or potentially serious side effects have been reported, including agranulocytosis, dysgeusia and reduced renal function; although a clear causal relationship with captopril was not always established, it would appear that the final place of captopril in the treatment of hypertension may ultimately depend on further clarification of its adverse effects profile. In addition to studies in hypertension, captopril has produced encouraging improvement in a small number of patients with severe congestive heart failure resistant to conventional therapy. Captopril must be considered an exciting addition to the therapeutic armamentarium; it, and pharmacologically related compounds of the future, will continue to generate much interest as their final place in therapy becomes better defined through additional well designed studies and wider clinical experience.

341 citations

Journal ArticleDOI
TL;DR: Seasonal influences on blood pressure are not limited to conventional measurements but characterize daily values as well, and are visible in both normal and elevated blood pressure values, regardless of the effect of antihypertensive drugs.
Abstract: ObjectiveClinic blood pressure values are known to change according to seasonal influences. We therefore examined home and 24 h ambulatory blood pressure values to determine whether these measurements are also affected by the seasons.Design and methodsIn 2051 subjects of the Pressione Arteriose Moni

209 citations