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Biomedical subjects

M Nakamaru

Publications and source records attributed to M Nakamaru.

99 records · Page 6Linked to original sources

Blood pressure response to an angiotensin II antagonist in patients with acromegaly.

The renin-angiotensin-aldosterone system in patients with acromegaly was evaluated by infusing [sarcosine1, isoleucine8]angiotensin II, a competitive angiotensin II antagonist, into five acromegalic patients with hypertension and three normotensive acromegalics. The drug was infused at a rate of 600 ng/kg . min for 30 min, 1 h after iv injection of 40 mg furosemide. In addition, before the infusion, plasma samples were obtained for determination of PRA and plasma aldosterone concentration. A significant pressor response to [sarcosine1, isoleucine8]angiotensin II was observed in all eight patients. Preinfusion PRA and plasma aldosterone concentration were significantly lower than in normal controls. It is concluded that in acromegaly, the renin-angiotensin-aldosterone system is suppressed and that this system is probably not involved in maintenance of the high blood pressure observed in some acromegalic patients.

Acromegaly↗

Blood pressure response to [1-sarcosine, 8-isoleucine] angiotensin II in patients with liver cirrhosis and ascites.

[1-Sarcosine, 8-Isoleucine] angiotensin II was given to 8 patients with cirrhosis and ascites and 7 cirrhotic patients without ascites on a regular diet. The 3 ascitic patients with high plasma renin activity (PRA) gave a depressor response, but the other ascite patients with normal or low PRA gave a pressor response or no response. All the non-ascitic patients gave a pressor response. There was an inverse correlation between the PRA before infusion and the change in blood pressure induced by this compound. In the patient with the highest PRA, who had ascites of a few days' duration, a marked reduction in blood pressure was observed on infusion of this compound. These results suggest that the renin-angiotensin system might be involved in maintenance of a normal blood pressure in some patients with cirrhosis and ascites, whose ascites is presumably in an early stage.

Aldosterone↗

Effects of an angiotensin II antagonist; [sarcosine 1, isoleucine 8] angiotensin II, on blood pressure, plasma renin activity and plasma aldosterone concentration in hypertensive and normotensive subjects taking oral contraceptives.

To examine the involvement of renin-angiotensin-aldosterone system in the etiology of oral contraceptive induced hypertension, normal women (Group I), normotensive (Group II) and hypertensive (Group III) women taking Ovulen (R) were infused with a competitive angiotensin II (AII) antagonist, [1-sarcosine, 8-isoleucine] angiotensin II. The angiotensin II antagonist was infused at a rate of 600 ng/kg/min for 30 min 1.5 hrs after intravenous injection of 40 mg of furosemide. Blood pressure was monitored and pre-infusion and post-infusion plasma renin activity (PRA) and plasma aldosterone concentration (PAC) were determined. Pre-infusion PRA and PAC showed no significant differences among these three groups. In response to the AII antagonist infusion blood pressure rose in Groups I and II, but blood pressure responses in Group III were variable. Four out of the total 6 subjects had pressor responses and only one subject had a significant blood pressure reduction. In both Groups I and II, PRA decreased and PAC rose after infusion of the antagonist. In Group III, PRA decreased to a lesser degree and PAC showed no consistent change. These data suggest that the renin-angiotensin-aldosterone system in hypertensive women or oral contraceptives is different from that of the normotensive users. However, the pathophysiology of oral contraceptive induced hypertension is not homogenous and angiotensinogenic hypertension is uncommon.

1-Sarcosine-8-Isoleucine Angiotensin II↗

[A study on the pathophysiology and diagnosis of adrenocortical insufficiency using angiotensin II blocker (author's transl)].

Angiotensin II analogue (AIIA), 1-sarcosine, 8-isoleucine angiotensin II (Sar1, Ile8-AII), was given in a graded dose to patients with adrenal hypofunction of various etiologies, and the blood pressure response to AIIA was observed to investigate the role of the renin-angiotensin system for the maintenance of blood pressure in the state of adrenal insufficiency. An agonistic pressor response to AIIA was observed in the control subjects without adrenal hypofunction. In contrast with this, patients with Addison's disease showed a blood pressure fall to AIIA. When the test was repeated on the same patients after hydrocortisone replacement, these patients showed a neutral or pressor response. Three patients with adrenalectomy and hydrocortisone replacement showed a pressor response to AIIA in a supine position. When these patients were tilted, fall in blood pressure to AIIA was observed in two of them who had been on a regular diet, whereas one patient who had been on a high sodium diet showed no fall in blood pressure with this procedure. We concluded that the renin-angiotensin system plays an important role in the maintenance of normal or subnormal blood pressure in Addison's disease and in the postural change of adrenalectomized patients on hydrocortisone and regular salt intake. The response of blood pressure to AIIA may be a clue for the diagnosis of Addison's disease and the evaluation of the adequacy of replacement therapy with regard to these patients.

Addison Disease↗

Comparison of two angiotensin II analogues in normal subjects and hypertensive patients.

Two angiotensin II analogues, i.e., 1-sarcosine, 8-isoleucine angiotensin II (Sar1, Ile8-AII) and 1-sarcosine, 8-alanine angiotensin II (Sar1, Ala8-AII), are now available in the clinical study. Comparative studies of the antagonistic potency and the agonistic effect of these two AII analogues were made in normal subjects on three sodium balances and in hypertensive patients with various etiologies on sodium depletion. Both AII analogues had an agonistic pressor effect in normal subjects. This effect changed with different sodium balances. In the low sodium state, this agonistic action was minimized. The agonistic pressor effect of Sar1, Ile8-AII was greater than that of Sar1, Ala8-AII in all sodium states. There was found an agonistic activity of both AII analogues not only on blood pressure, but also on renin and aldosterone secretion, and renal vasculature in normal subjects on a regular diet. The antagonistic depressor potency of both compounds was also varied by changing sodium balance, being greatest in the low sodium state. In hypertensive patients on sodium depletion, the blood pressure responses of individual patients to these two AII analogues were significantly correlated (r = 0.8, n = 20). These results indicate taht pretreatment of sodium depletion is necessary to prevent the side effect caused by the agonistic pressor action of AII analogue, and also to predict renin depency in hypertensive patients efficiently.

Adult↗

Effect of atrial natriuretic factor on central angiotensin II-induced responses in rats.

The effect of intracerebroventricular (ICV) injection of atrial natriuretic factor (ANF) on drinking and pressor responses induced by centrally administered angiotensin II (AII) was examined in the rat. The ICV injection of ANF attenuated water intake induced by AII or 48-hr water deprivation. In contrast, ANF did not affect AII-induced pressor responses. The ICV injection of ANF did not cause recognizable change in blood pressure in spontaneously hypertensive rats or Wistar-Kyoto rats. These results suggested that ANF in the brain is involved in the central control of water intake. Brain ANF may be considered as a selective antagonist of the dipsogenic effect of AII but not its pressor effect.

Angiotensin II↗

Technique for iliac artery reconstruction in abdominal aortic aneurysm repair.

The aim of this retrospective study was to evaluate the technique for iliac artery reconstruction in abdominal aortic aneurysm repair, when external and internal iliac arteries were required to reconstruct individually. Among 203 elective infrarenal abdominal aortic aneurysm repairs, 22 patients (10.8%) required individual reconstruction of bilateral or unilateral iliac arteries, including 56 external or internal iliac arteries. Mainly, three types of procedures were performed: (1) the external iliac artery was anastomosed to the end of the bifurcated graft limb in an end-to-end manner, and the internal iliac artery was attached to the side of the external iliac artery, (2) the external iliac artery was anastomosed to the end of the bifurcated graft limb in an end-to-end manner and the internal iliac artery was bypassed with the use of a straight prosthetic graft extending from the limb of the bifurcated graft, and (3) the internal iliac artery was anastomosed to the end of the bifurcated graft limb in an end-to-end fashion, and the external iliac artery was sewn to the side of the graft limb. In these three types of procedures, the third technique was the easiest and simplest anatomically.

Aged↗