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R B Hickler

Publications and source records attributed to R B Hickler.

36 records · Page 2Linked to original sources
PubMed1970

Hypertension.

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Anesthesia↗
PubMed1969

Studies on the role of angiotensin in experimental renovascular hypertension: an immunologic approach.

The role of angiotensin in three forms of experimental hypertension was assessed in rats. First, the acute blood pressure response to injected angiotensin amide and angiotensin acid was determined. Rats made hypertensive with deoxycorticosterone and saline showed exaggerated responses; rats made hypertensive by clipping one renal artery showed depressed responses; and rats made hypertensive by clipping one renal artery and contralateral nephrectomy showed normal responsivity to angiotensin amide but depressed responsivity to angiotensin acid. These findings suggested that different mechanisms may be involved in the three types of hypertension studied. To assess the role of angiotensin in these hypertensive rats the blood pressure response, the presence of antibodies determined by radioimmune techniques, and the degree of refractoriness to injected angiotensin after immunization with angiotensin were studied. None of six rats made hypertensive by deoxycorticosterone and saline, and none of five mock immunized rats with renal hypertension of both types had a fall in blood pressure. By contrast, of the 20 rats with both types of renal hypertension in which antibody determinations were made, 11 had developed a significant antibody titer, of which seven showed a significant reduction in blood pressure at the time of antibody determination, and three of the remaining four had a significant blood pressure reduction earlier in their course. None of the nine renal hypertensive rats without demonstrable antibodies had a reduced blood pressure at the time of antibody determination, and only one had an earlier reduction in blood pressure. The renal hypertensive rats were all refractory to injected angiotensin after immunization. These results suggest a primary role for angiotensin in both forms of renal hypertension.

Angiotensin II↗
PubMedDate not supplied

Studies of the renin-renin substrate reaction in man; kinetic evidence for inhibition by serum.

Increasing evidence suggests that the renin-renin substrate reaction is regulated by factors other than the concentrations of enzyme and substrate. Partially purified human renin and renin substrate extracted from the plasma of each of eight human subjects were used to construct substrate-velocity curves comparing the rate of substrate cleavage in the whole serum of each individual with the rate in a corresponding system containing purified autologous substrate, or purified substrate plus a small amount of autologous serum. Linear regression analysis of the double reciprocal plots were used to compare the kinetic constants in paired experiments. Maximal reaction velocity (Vmax) was significantly lower (p greater than .05) when the reaction rate was measured in whole serum, in seven of the eight patients, while Km did not differ significantly, suggesting the presence of noncompetitive inhibition by human serum. The mean Michaelis constant in serum was 449 ng/ml while the average native substrate concentration of the five normal subjects was 629 ng/ml, an excess of less than twofold. The data suggest that plasma renin activity in man depends upon the concentrations of inhibitor and substrate, as well as upon the concentration of renin.

Angiotensin II↗