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Biomedical subjects

M Alderman

Publications and source records attributed to M Alderman.

17 recordsLinked to original sources
PubMed1997

Urinary sodium excretion and myocardial infarction in hypertensive patients: a prospective cohort study.

Reduced-sodium diets are frequently recommended for hypertensive patients. To determine the relation of sodium intake to subsequent cardiovascular disease, 24-h urinary excretion of sodium, potassium, and creatinine and plasma renin activity (PRA) were measured in 2937 mildly and moderately hypertensive patients unmedicated for > or = 3-4 wk. Morbidity and mortality in these treated subjects were ascertained. Subjects were stratified by sex-specific quartiles of urinary sodium excretion; race, cardiovascular status, and blood pressure before and during treatment were similar for each stratum. Patients with lower urinary sodium excretion were thinner, excreted less potassium, and had higher PRA. During an average 3.8-y follow-up, 55 myocardial infarctions (MIs) occurred. Incidence of MIs and urinary sodium excretion were inversely associated in the total population and in males but not in females. In males, age- and race-adjusted MI incidence in the lowest compared with the highest quartile of urinary sodium excretion was 11.5 compared with 2.5 (RR: 4.3; 95% CI: 1.7, 10.6). No association was observed between mortality from causes other than cardiovascular disease (n = 11) and urinary sodium excretion. There was a significant linear trend in proportions of MI by quartile of urinary sodium excretion, with a breakpoint after the lowest quartile. In Cox multivariate analysis, the logarithm of PRA, age, systolic blood pressure, and cholesterol as continuous variables, as well as left ventricular hypertrophy and smoking, had a direct association and urinary sodium excretion an inverse, independent association (P = 0.036) with incidence of MI.

Cardiovascular Diseases↗
PubMed1996

Novel delivery system for verapamil designed to achieve maximal blood pressure control during the early morning.

Because the risk of cardiovascular events appears to be greatest in the early morning, this period is a time during which adequate blood pressure (BP) control appears to be most desirable. In this study, a controlled-onset extended-release system (COER-24) that delivers verapamil in a manner designed to achieve maximal levels of drug during the early morning surge in BP was compared with placebo. Ninety-five patients with mild to moderate hypertension were studied. Of this group, 49 patients (mean age 57.6 +/- 1.4 years; 35 men and 14 women) were randomized to take verapamil COER-24 240 mg at 10 PM, and 46 subjects (mean age 55.8 +/- 1.5 years; 29 men and 17 women) were randomized to take placebo. Ambulatory BP monitoring was performed after a 4-week initial placebo period and was repeated after 4 weeks of treatment with verapamil or placebo. Verapamil COER-24 resulted in significant (p < 0.001) decreases in mean whole-day systolic and diastolic BP (-8.2/-6.3 mm Hg; baseline 152/93.0 mm Hg) when compared with placebo (+0.3/-0.9 mm Hg; baseline 150.3/93.2 mm Hg). From 6 AM to noon, verapamil COER-24 resulted in a change in systolic and diastolic BP of -11.6/-9.0 mm Hg, which was significantly (p < 0.001) greater than the change that occurred with placebo (-0.5/-1.0 mm Hg) during the same period. In the last 4 hours of the dosing interval (6 PM to 10 PM), verapamil COER-24 caused significantly greater (p < 0.001) decreases in BP (-7.4/-4.8 mm Hg) than did placebo (+2.7/+1.0 mm Hg). These data demonstrate that the COER-24 system, when administered in the late evening, achieves maximal BP reduction during the early morning hours. Moreover, BP reductions were sustained throughout the 24-hour period.

Blood Pressure↗
PubMed1990

The relationship between 'job strain,' workplace diastolic blood pressure, and left ventricular mass index. Results of a case-control study.

To determine whether "job strain" (defined as high psychological demands and low decision latitude on the job) is associated with increased workplace diastolic blood pressure and the left ventricular mass index, we conducted a case-control study at seven urban work sites of 215 employed men aged 30 to 60 years without evidence of coronary heart disease. After comprehensive blood pressure screening of male employees (N = 2556) at the work site, 87 cases of hypertension and a random sample of 128 controls were studied. In a multiple logistic regression model, job strain was significantly related to hypertension, with an estimated odds ratio of 3.1, after adjusting for age, race, body-mass index, type A behavior, alcohol intake, smoking, work site, 24-hour urine sodium excretion, education, and physical demand level of the job. Controlling for the above variables in subjects aged 30 to 40 years with job strain, we found that the echocardiographically determined left ventricular mass index was, on average, 10.8 g/m2 greater than in subjects without job strain. We conclude that job strain may be a risk factor for both hypertension and structural changes of the heart in working men.

Adult↗
PubMed1988

A longitudinal study of urinary creatinine and creatinine clearance in normal subjects. Race, sex, and age differences.

The purpose of this study was to examine the variability of 24-hour urinary and serum creatinine levels and creatinine clearance in normal subjects and to develop nomograms for assessing the adequacy of 24-hour urine collections. The data were from a longitudinal research program examining biochemical, hormonal, and hemodynamic parameters in normal subjects. Bloods and 24-hour urine specimens were collected at yearly intervals from 144 people over 9 years, and from an additional 110 over 4 years. The subjects were originally distributed equally by sex, race (black, white), blood pressure (three groups within the normal range), and age (three groups). Men had 33% higher urine creatinines per weight than females (P less than 0.001). Because they only had 8% higher creatinine clearance per weight they also exhibited 21% higher serum creatinine. Blacks had 5% higher urine creatinine per weight than whites, perhaps reflecting greater muscle mass, but their serum creatinines were not different from those of whites, reflecting a 5% higher creatinine clearance by weight than whites (P less than 0.01). Interestingly, older black men (age greater than 60 years) had 12% lower urine creatinine/weight than younger black men (P less than 0.001). They also had 13% lower creatinine clearance by weight, resulting in no net difference in serum creatinine. The intraindividual variability in urine creatinine excretion averaged 15% and did not differ between blacks and whites and men and women. The within individual variability in serum creatinine and creatinine clearance averaged 14 and 20%, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1986

Renin relationship to sex, race and age in a normotensive population.

The relationship of renin activity to sex, race (black or white) and age (less than 50 or greater than or equal to 50 years of age) was examined in 236 normal subjects measure yearly for up to 9 years. There were 58 white women (34 less than 50 years, 24 greater than or equal 50 years), 66 white men (30 less than 50 years, 36 greater than or equal to 50 years), 57 black women (34 less than 50 years, 23 greater than or equal to 50 years) and 55 black men (34 less than 50 years, 21 greater than or equal to 50 years). The results showed men had higher mean renin activities than women, whites had higher activities than blacks and those of under 50 years had higher activities than those of over 50 years. However, the sex and race differences primarily occurred as a consequence of a lack of decline in renin activity with age among white men. The relationship with age as a continuous variable was weak (r = -0.21) and no relationship with age was found in 22 subjects with a least 7 years of data. No significant differences in urinary sodium excretion were observed between the groups. These results suggest that renin activity tends to be lower in older subjects and that differences in renin activity related to sex and race, while statistically significant, may not be physiologically important.

Age Factors↗
PubMed1985

Intermittent claudication: a double-blind crossover trial of pentoxifylline.

The influence of the xanthine derivative pentoxifylline ('Trental' or BL191; Hoechst-Roussel) on exercise tolerance was measured in 38 subjects with stable, severe to moderately severe, intermittent claudication who completed a randomised, double-blind, placebo controlled, cross-over clinical trial. Patients received placebo tablets or 400 mg slow-release pentoxifylline tablets ('Trental 400') twice a day for one week, followed by three times daily for seven weeks, and then crossed over to receive the alternate preparation for another eight weeks. Claudication distance and walking distance were measured on a treadmill before starting treatment and again at four-week intervals during the trial. At the same times, red blood cell filterability, plasma fibrinogen concentration and blood viscosity, resting and post-ischemic calf muscle blood flow, and the resting and post-exercise ankle/brachial systolic pressure ratio were also measured. In this study, the observed effects of pentoxifylline treatment were no greater than those of placebo, even though serum levels of pentoxifylline and its hydroxy-metabolite were within the anticipated range. This was shown by a 'therapeutic effect ratio' of 0.98 for treadmill claudication distance and 0.96 for treadmill walking distance after within-patient analysis at the end of the cross-over (where a ratio of 1.0 means the test drug and placebo effects are identical). These ratios have 95% confidence limits of 0.72-1.34 and 0.74-1.25, respectively.

Aged↗
PubMed1982

Absenteeism and labelling in hypertensive subjects. Prevention of an adverse impact in those at high risk.

In this work-site population, the illness absenteeism of 259 hypertensive subjects was studied in the year after they were screened and labelled. Absenteeism due to illness increased more in 48 patients who were unaware of their hypertension (newly labelled) than in the 211 subjects who were aware. Among the newly labelled subjects, only the young subjects and those with "pure" systolic hypertension experienced increased absenteeism; the older subjects with diastolic hypertension did not. The newly labelled subjects who received active follow-up and treatment with antihypertensive medication had only minimal increases in absenteeism. In contrast, those who received active follow-up without medication, and those who received only episodic follow-up had significantly greater increases. Vigorous efforts are warranted to insure active follow-up and treatment for hypertensive subjects after their condition has been labelled. Caution should be exercised in labelling, however, if no antihypertensive treatment is initiated.

Absenteeism↗
PubMed1976

Plasma prorenin: cryoactivation and relationship to renin substrate in normal subjects.

We previously demonstrated an inactive form of renin, termed prorenin, in the plasma of normal, hypertensive and anephric patients. Prorenin activity can be determined in plasma from the total renin activity after activation, minus the prior endogenous plasma renin activity. In the present study, conditions for cryoactivation of prorenin have been defined. Plasma prorenin is slowly converted to active renin-like material at -5 degrees C at pH 7.4. Activation takes four days and does not occur at pH 5.0. The degree of activation increases above pH 5 and is greatest between pH 7 and pH 9. Thus, almost no cryoactivation of prorenin occurs at the pH optimum for renin (5.7) in contrast to maximum activation at pH 7.4. No activation has been observed in the frozen state, but it does occur with decreasing rapidity at temperatures from -5 degress to +4 degress C. Since blood samples obtained for the determination of plasma renin activity are routinely chilled upon collection by most laboratories, some activatin of prorenin most likely occurs in all routine renin assays. The pH optimum of the enzymatic reaction of the activated prorenin in plasma is 5.8, the same as for renal renin, and the shape of the pH optimum curve is similar to that of renal renin added to human plasma. In a group of 23 normal subjects with plasma renin activity of 3.5 +/- 2.9 (SD), the activated prorenin increment was found to be significantly higher, 6.3 +/- 5.0 (SD) ng/ml/hour. Unlike plasma renin activity, prorenin activity in these normal subjects was directly related to the concentration of renin substrate (p less than 0.001). When the actual "concentration" of prorenin was calculated using renal renin as the reference standard, a direct relationship was also found between the concentration of prorenin and renin substrate (p less than 0.01). The observed relationship between prorenin and renin substrate concentrations might be a consequence of their regulation by common factors.

Angiotensin II↗
PubMedDate not supplied

The coming of age in nursing care of the elderly.

Worldwide trends and developments point the way toward a restructuring of health care delivery systems to meet increased demands from the elderly and disabled. As nursing, by virtue of its unique position, can play a major role in gerontological care, below the authors present three models that optimize nursing care to ensure effective and efficient service.

Aged↗