Real-time digital processing of blood pressure and heart rate data of tethered nonhuman primates.

To facilitate data analysis, we developed a computerized system for collecting and screening systolic, diastolic, and mean arterial blood pressure, and heart rate data. Each value is tested for acceptability (filtered), in real-time, by a computer algorithm. Level one, spike detection, is performed by independently comparing each datum to specified upper and lower limits. Level two, damping detection, is applied to data which passed level one and is categorized as mild, severe, or none. We monitored 69 tethered conscious baboons for approximately eight 12-hour overnight periods to obtain 23,433,000 one-second data points per variable. The computerized system eliminated approximately 65% of unacceptable data and highlighted problems, thus reducing the time required to inspect digital files or analog hard-copy recordings. No acceptable data were rejected by the filter and all data rejected by the filter also were unacceptable by data inspection.

Effects of two forms of hypertension on atherosclerosis in the hyperlipidemic baboon.

We examined the relationship of hypertension and plasma renin activity to atherogenesis in 48 moderately hyperlipidemic (total serum cholesterol was about 200 mg/dl) baboons (Papio sp.). We used renal artery stenosis (two-kidney, one clip model) to produce hypertension associated with elevated plasma renin activity, and used cellophane wrapping of both kidneys (bilateral perinephritis model) to produce hypertension with normal renin activity. Renal artery stenosis and bilateral perinephritis increased both systolic and diastolic blood pressure by about 30 mm Hg. Renal artery stenosis approximately doubled, but bilateral perinephritis did not change plasma renin activity. Both hypertensive groups, to about the same degree, had significantly more extensive atherosclerosis than the control group in the abdominal aorta and brachial, iliac-femoral, and carotid arteries. The effect of hypertension was greatest in the carotid arteries where the extent of atherosclerosis was nearly tripled. Hypertension did not influence lesions in the thoracic aorta. By multiple regression analysis, very low plus low density lipoprotein cholesterol, high density lipoprotein cholesterol, and systolic blood pressure were consistently strong predictive variables for the extent of atherosclerotic lesions. Most of the effects of renal hypertension on atherosclerotic lesions appeared to be accounted for by the increase in blood pressure. In the carotid arteries, however, there was a suggestion of an effect above that due to increased blood pressure. Additional analyses indicated that these treatment effects were associated with serum potassium concentration, plasma renin activity, or other closely related variables.