Pneumocystis carinii pneumonia in a previously healthy adult.
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Adult↗
Biomedical subjects
R D Watson
Publications and source records attributed to R D Watson.
Systolic fluttering of the tricuspid valve in a patient with high interventricular-septal defect.
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Adult↗
The effect of nifedipine on arterial pressure and reflex cardiac control.
Nine patients with untreated, essential hypertension (mean casual blood pressure 173/109 +/- 14/7 mmHg (+/- s.d.] were studied in the control state and then following 16 weeks treatment with nifedipine 10 mg orally 8 hourly. Direct arterial blood pressure was monitored continuously over 24 hours and demonstrated that nifedipine significantly reduced systolic and diastolic blood pressure throughout the day and the night. The variability of blood pressure was not altered by nifedipine therapy. There was no significant change in heart rate after nifedipine therapy. At each study the sensitivity and setting of the baroreflex response to intravenous phenylephrine was measured. Following chronic nifedipine therapy there was re-setting of the sino-aortic baroreflex and an increase in its sensitivity.
Adult↗
Assessment of left-ventricular mass and its response to antihypertensive treatment.
50 patients with mild to moderate essential hypertension underwent M-mode echocardiography and continuous intra-arterial ambulatory monitoring of blood pressure. Indices of left-ventricular (LV) mass were derived from echocardiographic data by standard formulae. 43 of the patients were followed up for 12+/-7 months with repeat M-mode echocardiography, and casual blood-pressure measurements. 25 of these patients received antihypertensive therapy and 18 were untreated. Mean 24 h systolic blood pressure was significantly correlated with echocardiographic LV mass; mean 24 h diastolic blood pressure was also correlated, but the relation was weaker. In the treated group there was a significantly greater fall in blood pressure and LV mass index than in the untreated group, and there was a significant correlation between the fall in systolic blood pressure and the fall in LV mass index in the treated group. Systolic blood pressure appears to be an important factor in the pathogenesis of LV hypertrophy, and in hypertensive patients changes in LV mass assessed by echocardiography correlate with changes in blood pressure.
Adolescent↗
Applications of multidimensional computer graphics in medical systems.
Multidimensional computer graphics are demonstrated in two medical systems applications in this paper. First, multidimensional computer graphics are utilized for descriptive purposes to show the differences among 10 physician specialty groups for multivariate data available at admission to medical school. Second, multidimensional computer graphics are demonstrated as a method that can be used for screening school applicants. The novel method utilized to represent multivariate data requires the plotting of a face. Each feature of a face--for example, face height or ear diameter-can be utilized to represent a different dimension of multivariate data. Each face then represents a vector whose elements are the mean values of multiple variables, or it represents a multivariate observation.
Career Choice↗
Sequential changes in plasma noradrenaline during bicycle exercise.
1. Forearm venous plasma noradrenaline, heart rate and intra-arterial blood pressure were measured sequentially during and after upright bicycle exercise in five normotensive and six hypertensive patients. 2. Plasma noradrenaline increased significantly between 4 and 8 min during exercise. 3. On stopping exercise blood pressure and heart rate decreased rapidly whilst plasma noradrenaline increased in each subject to reach a maximum at a median time of 108 s after exercise. 4. Plasma noradrenaline decreased in five of six normotensive patients between the end of exercise and 2 min after exercise performed in the supine position. 5. Evidence in favour of a reflex increase in sympathetic activity after upright exercise is discussed.
Adult↗
The influence of physical activity on arterial pressure during ambulatory recordings in man.
1. Ambulatory blood pressure recordings were made over a 48 h period on six hypertensive patients. The conditions of study were standardized, particularly with regard to physical activity, and during one period of each day the patients were randomly allocated to be active or inactive. 2. Results show that blood pressure was highest during physical activity and lowest during sleep. There was no significant difference between the arterial pressures measured during the same physical activities carried out at the same time each day. However, during the same time on consecutive days when activity was randomized, there was a significant difference between the pressure recordings during physical activity compared with those during inactivity. Heart rate changes showed a similar trend during the randomized period. 3. Physical activity and sleep have a profound effect on continuous arterial blood pressure recordings and these are independent of time alone. These observations should be taken into account when using this ambulatory system to assess hypotensive therapy.
Adult↗
Protein Malnutrition and complement activity in guinea pigs, germ-free and conventional rats.
Malnutrition produces a pronounced effect on the complement system of man and animals. There is little information, however, to indicate whether individual complement components are affected at different stages of age. In the following studies, we have demonstrated that in guinea pigs and in both conventional and germ-free rats, protein malnutrition adversely affects the complement system. The levels of complement components C2 and C3 are suppressed by protein malnutrition at an early stage while C4 and C8 are less affected by malnutrition. Experiments in germ-free animals demonstrated that decreased complement component levels can be directly associated with decreased synthesis and/or secretion of components. In conventional animals, further reductions in complement levels could occur as a result of infection associated with malnutrition.
Animals↗
Comparison of once and twice daily administration of acebutolol in hypertension.
1 Thirteen hypertensive patients completed a double-blind comparison of placebo, acebutolol 200 mg twice daily and acebutolol 400 mg once daily, administered for 4 weeks in random order. 2 Blood pressure and heart rate were significantly reduced by both acebutolol treatments. The mean reduction of resting pressure 12 h after 200 mg twice daily (12/7 mmHg) was similar to that 24 hr after 400 mg once daily (13/9 mmHg). 3 Compared to placebo, reductions in exercise heart rate and systolic pressure at 12 h after 200 mg twice daily and 24 h after 400 mg once daily were significant and similar. 4 Beta-adrenoceptor antagonism was also assessed by inhibition of the heart rate response to sublingual glyceryl trinitrate taken in the standing position. Both acebutolol treatments reduced the response; the reduction after twice daily treatment (mean 25 beats/min) was significantly greater than after once daily treatment (mean 19 beats/min). 5 There was no difference in blood pressure control between acebutolol administered once and twice daily in a total daily dose of 400 mg.
Acebutolol↗
Changes in plasma noradrenaline and adrenaline during isometric exercise.
1. Plasma noradrenaline and adrenaline were measured radioenzymatically in twelve hypertensive and four normotensive subjects before and during handgrip. In the resting arm (n=11), plasma noradrenaline increased by 17% (P<0.01) and plasma adrenaline by 27% (P<0.001). In the exercising arm, plasma adrenaline increased by 97% (P<0.005) but the mean increase of noradrenaline of 10% was not significant (P>0.1). 2. The noradrenaline response suggests a small and variable sympathetic adrenergic response; the significant difference (P<0.05) in adrenaline responses between resting and exercising arms may reflect local variation in tissue clearance.
Adult↗
Influence of once-daily administration of beta-adrenoceptor antagonists on arterial pressure and its variability.
Intra-arterial pressure was recorded over 24 h in hypertensive patients before and during long-term treatment with beta-adrenoceptor antagonists given once daily under standardised conditions. Arterial pressure was reduced throughout the 24 h after the last dose as was variability of pressure during physical activity; variability during sleep and rest did not change significantly.
Acebutolol↗
Effect of once-daily atenolol on ambulatory blood pressure.
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Adult↗
Effects of beta-adrenoreceptor antagonists on sino-aortic baroreflex sensitivity and blood pressure in hypertensive man.
1. Sensitivity of the sino-aortic baroreflex was investigated before and after acute (23 patients) and chronic (23 patients) beta-adrenoreceptor antagonism in patients with essential hypertension. 2. Sensitivity was inversely related to age (r = -0.60) and systolic blood pressure (r = -0.46); a positive relationship was noted between sensitivity and initial pulse intervals (r = 0.40). 3. Sensitivity increased significantly in patients less than 40 years of age after chronic treatment. No change occurred after acute treatment or in older patients treated chronically. 4. The fall in ambulatory intra-arterial blood pressure after chronic treatment was unrelated to alteration of baroreflex sensitivity.
Acebutolol↗
Plasma noradrenaline concentrations at different vascular sites during rest and isometric and dynamic exercise.
1. Blood samples were obtained simultaneously from femoral artery and vein, pulmonary artery and antecubital vein at rest and during isometric and dynamic exercise in six patients during cardiac catheterization and plasma noradrenaline was measured radioenzymatically. 2. Analysis of variance indicated that differences between vascular sites were not significant, whereas differences between patients (P less than 0.001) and differences between activities (P less than 0.001) were significant. 3. Mean systemic arterial concentrations tended to be lower than pulmonary arterial concentrations during each activity, although the difference was not significant. 4. We conclude that forearm venous plasma noradrenaline concentrations are representative of those from other sites.
Adult↗
Factors determining the variability of arterial pressure in hypertension.
1. Intra-arterial pressure was recorded continuously in 26 patients with uncomplicated essential hypertension under standardized conditions. Pressure was analysed beat by beat by computer and variability measured as the standard deviation of the normally distributed frequency histogram. 2. Variability was strongly influenced by physical activity, being least during sleep and increasing progressively with bed rest and ambulation. Variability during daytime was not related to time. 3. Systolic variability correlated directly with systolic pressure. An independent inverse relationship with baroreflex sensitivity was observed. Systolic variability tended to increase with obesity. 4. None of the following were related independently with variability: age; race; sex; plasma renin activity; plasma angiotensin II; plasma noradrenaline; plasma adrenaline.
Adolescent↗
Onset and duration of beta-adrenergic receptor blockade following single oral dose acebutolol hydrochloride (Sectral).
1. The onset and duration of action of once daily acebutolol (400 mg) on resting and exercise heart rate and blood pressure were studied in normal subjects in a double-blind, cross-over trial against placebo. Subjects were studied 1.5, 3, 8 and 24 h after the first dose and 24 h after the fifth dose. 2. Resting and exercise heart rate and blood pressure were significantly reduced within 90 min of the first dose. 3. A significant reduction in these variables persisted throughout 24 h after the fifth daily dose. However, at 24 h the effects were considerably attenuated, the falls in resting and exercise systolic blood pressure being only 5%. 4. A linear relationship was noted between log serum drug level and percentage reduction of exercise heart rate.
Acebutolol↗
The Remler M2000 semi-automatic blood pressure recorder.
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Blood Pressure Determination↗