Left ventricular mass index and coronary artery disease in hypertensive black males.

Thallium-201 stress scintigraphy (TSS) and echocardiography were performed on 60 consecutive black male hypertensives and compared to 60 sex-, race-, and age-matched controls. We found a higher prevalence of left ventricular hypertrophy with repolarization abnormality in the hypertensive group; 32 of 60 (53%), compared to 10 of 60 (17%) of the controls, P < .05. Echocardiographically determined left ventricular mass index revealed a significantly higher mean value in the hypertensive group of 147 +/- 57 compared to 124 +/- 34 in the control group, P < .001. Thirty-one of 60 (52%) of the hypertensive group had a normal TSS compared to 22 of 60 (37%) of the controls. A total of 68 (38 fixed and 30 reversible) perfusion defects were noted in the hypertensive group compared to 74 (55 fixed and 19 reversible) in the controls. The severity of clinical syndromes associated with myocardial ischemia were noted in increased incidence in the presence of left ventricular hypertrophy and left ventricular mass index was noted to be predictive of severity of coronary disease independent of the standard risk factors.

Inhibition of inositol phospholipid hydrolysis in endothelial cells by pentobarbital.

Barbiturates alter cardiovascular function, in part by an effect on vascular cells. However, a biochemical mechanism for the effect is unknown. We have, therefore, studied the effect of barbiturates on inositol phospholipid hydrolysis in cultured rat aortic endothelial cells. Hydrolysis was stimulated by angiotensin II, norepinephrine and phenylephrine. Pentobarbital, and other barbiturates, inhibited hydrolysis at pharmacological and clinical concentrations (0.1-0.5 mM). The inhibition by pentobarbital was concentration-dependent, reversed by washing, and was decreased by high concentrations of angiotensin II. Kinetic studies gave an apparent Km of hydrolysis by angiotensin II of 1.2 nM, which showed mixed inhibition by pentobarbital (Ki = 0.45 mM). Schild analysis of data obtained from pentobarbital inhibition curves also showed a deviation from a competitive type inhibition. [125I]Angiotensin II was bound to a high-affinity receptor (Kd = 1.2 nM), which showed a competitive type inhibition of binding by pentobarbital (0.5 mM). Although inhibition of [125I]angiotensin II binding appeared to be competitively inhibited by pentobarbital, the data, taken together, point to a deviation from a simple competitive type inhibition.

Acetylation of spermidine and methylglyoxal bis(guanylhydrazone) in baby-hamster kidney cells (BHK-21/C13).

Treatment of BHK-21/C13 cells with methylglyoxal bis(guanylhydrazone) (MGBG) induced the cytosolic form of spermidine N1-acetyltransferase. It stabilized the enzyme against proteolytic degradation, but the drug did not affect the enzyme activity in vitro. MGBG was itself acetylated by BHK-21/C13 cells, but at only one-tenth the rate at which spermidine was acetylated. Acetylation occurred almost exclusively in the nuclear fraction. The product was identified as N-acetyl-MGBG by h.p.l.c., by using [3H]acetyl-CoA and [14C]MGBG as co-substrates. The results suggest that the acetylation of MGBG by BHK-21/C13 cells occurs by a different acetyltransferase enzyme from that which acetylates spermidine.

A comparison of phenytoin dosing methods in private practice seizure patients.

In an attempt to evaluate the accuracy of phenytoin (PHT) pharmacokinetic dosage adjustments in a private practice setting, three single dose-concentration pair methods and three multiple point PHT pharmacokinetic dosing methods were studied. Dose and concentration data from 28 patients seen in a private neurology practice were utilized for the study. From a comparison of these methods in private practice seizure patients, it appears that the Bayesian feedback method may be the most accurate in making routine PHT dosage adjustments, perhaps by minimizing the contribution of unknown variables within the Bayesian approach.

A graphic method for predicting individual phenytoin levels in an office practice.

A simple method is described for predicting a desired steady-state phenytoin plasma level based on two steady-state phenytoin plasma levels achieved at different daily doses. In this graphic method, radial vectors corresponding to specific concentrations are plotted on a clearance-versus-dose graph. These vectors are used to determine a new phenytoin dose that will predict a desired level directly from the graph. Evaluation in an office practice of this method and a computerization of the equation on which it is based demonstrate that it is a practical aid in individualizing phenytoin therapy.

Predicting individual phenytoin serum levels of patients seen in a private office practice.

We evaluated the practicality of predicting phenytoin serum levels in an office practice. Once two phenytoin serum levels were obtained on two different dosage regimens, a table of future doses and predicted serum levels was calculated and plotted on a graph. Subsequent dosage adjustments resulted in serum levels that correlated well with predictions. In 7 of 10 patients, the predicted serum levels were within 2 micrograms per milliliter of the actual values. To improve compliance, the plot was used as a visual aid in patient education.

Eugenic sterilization: medico-legal and sociological aspects.

The court-ordered sterilization of a normal 18-year-old black female in North Carolina focused attention on the unfortunate impact of eugenic statutes that allow sterilization as a method of social control. The existence of these laws in many states allows misapplication and abuse of authority which, not infrequently, is directed liberally to blacks and other minority groups.Eugenic sterilization is, at this time, a legally accepted form of "medical treatment." The justification of such sterilization is the vague concept that the presumed "mentally deficient" individual is probably a potential parent of socially inadequate offspring who would likewise be socially inadequate.Since there never has been factual substantiation of whether the sterilization of these individuals will diminish the incidence of mental retardation, it is necessary to focus attention on the concept of eugenic sterilization and point out its many fallacies.

Electrocardiographic findings in patients with obstructive and nonobstructive hypertrophic cardiomyopathy.

One hundred and thiry-four patients with hypertrophic cardiomyopathy were evaluated by standard 12-lead electrocardiography. Normal electrocardiograms were extremely uncommon, occurring in less than 7% of each subgroup of patients (i.e., those with or without either symptoms or obstruction to left ventricular outflow), with the exception of those who were both asymptomatic and had no left ventricular outflow obstruction. Even in this subgroup, however, normal electrocardiograms occurred in only 27% of patients. Repolarization abnormalities and left ventricular hypertrophy were the most common abnormalities, occurring in 81% and 62%, respectively, of the total population. A broad spectrum of other electrocardiographic abnormalities was found, but none was unique to hypertrophic cardiomyopathy. Patients with vs those without electrocardiographic left ventricular hypertrophy or left atrial abnormality had significantly (P less than 0.005) greater mean ventricular septal thickness (22 +/- 0.6 vs 19 +/- 0.6 mm) and left atrial dimension (48 +/- 1 vs 40 +/- 1 mm) measured by echocardiography, and signficantly (P less than 0.01) higher mean pulmonary capillary wedge pressure (16 +/- 1 vs 10 +/- 1 mm Hg) and left ventricular end-diastolic pressure (20 +/- 1 vs 15 +/- 1 mm Hg). The high prevalence and diverse nature of electrocardiographic abnormalities suggest that any patient with an unusual and unexplained electrocardiogram should be suspected of having hypertrophic cardiomyopathy even if the physical examination is normal, as is often the case in patients without obstruction.