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Biomedical subjects

K Takikawa

Publications and source records attributed to K Takikawa.

At least 37 records · Page 2Linked to original sources

Serum dopamine beta-hydroxylase activity in essential hypertension.

1. Serum dopamine beta-hydroxylase activity was determined in normotensive control subjects and patients with labile or established essential hypertension. The enzyme activity was 25-9 +/- 1-9 (SEM) 29-6 +/- 2-5 and 25-1 +/- 1-9 micronmol min-1 1-1, for control, labile and established hypertensive subjects respectively. 2. Neither blood pressure nor serum dopamine beta-hydroxylase activity was changed in normotensive control subjects by administration of phentolamine; however, in patients with essential hypertension blood pressure was significantly decreased (P is less than 0-01) and serum dopamine beta-hydroxylase activity was slightly increased. With propranolol administration, blood pressure and the serum enzyme activity were not significantly changed in normotensive or hypertensive subjects. 3. Our results suggest that there is no correlation between serum dopamine beta-hydroxylase activity and blood pressure.

Dopamine beta-Hydroxylase↗

Calcium uptake, release and Mg-ATPase activity of sarcoplasmic reticulum from arterial smooth muscle.

Sarcoplasmic reticulum (SR) isolated from rat aorta exhibited ATP dependent Ca2+ uptake in the presence of Mg2+. The maximum capacity and apparent binding constant were 23n moles/mg and 1.8 X 10(4) M (-1), respectively. The energy source of this active Ca2+ accumulation would be Mg-ATPase associated with the membrane. Ca2+ which was taken up inside of sarcoplasmic reticulum was released rapidly by washout with the medium containing no Ca2+. These facts suggest that sarcoplasmic reticulum in vascular smooth muscle cell may play and important role in the regulation of intracellular Ca2+ concentration.

Adenosine Triphosphatases↗

Serum dopamine-beta-hydroxylase activity in essential hypertension and in chronic renal failure with hypertension.

Elevated serum DBH (dopamine-beta-hydroxylase) activity was found in essential hypertension. The elevated level was not reduced when blood pressure was brought to normotensive level by administration of thiazide or rauwolfia. In contrast, serum DBH activity was low in both normotensive and hypertensive patients treated on prolonged hemodialysis. However, there was no correlation between serum DBH activity and blood pressure level. It was suggested that the pathogenesis of high blood pressure might be different between essential hypertension and hypertension with chronic renal failure, and that measurement of serum DBH activity might help for clinical differentiation of essential hypertension from certain forms of secondary hypertension.

Benzothiadiazines↗