Blood pressure, plasma volume, and catecholamine levels during enalapril therapy in blacks with hypertension.

The effect of enalapril, an antihypertensive inhibitor of angiotensin-converting enzyme, on plasma catecholamine levels and plasma volume (PV) has not been well established. In a randomized, double-blind study, 29 subjects (28 blacks and one white) received one of the following dosing regimens: hydrochlorothiazide (HCTZ), 25 mg twice a day (group 1; n = 12); enalapril, 10 mg twice a day (group 2; n = 12); or enalapril, 10 mg twice a day, with HCTZ, 25 mg twice a day (group 3; n = 5). Dosages were doubled after 4 wk if diastolic blood pressure was greater than or equal to 90 mm Hg. After 8 wk of therapy, supine blood pressure decreased by 24.1/16.0 mm Hg (systolic/diastolic) in group 1, by 10.8/4.0 mm Hg in group 2, and by 48.0/27.8 mm Hg in group 3. Mean values of supine plasma levels of norepinephrine, epinephrine, and dopamine did not change with therapy. PV fell 7.9% in group 1, 1.3% in group 2, and 5.0% in group 3. There were no correlations between changes in PV and blood pressure, but a decrease in PV correlated with an increase in plasma norepinephrine levels in the group treated with HCTZ alone (r = -0.65) and in all 29 subjects combined (r = -0.45). Enalapril alone was not very effective in lowering blood pressure in these subjects, but the combination of enalapril with HCTZ was very effective. There was no evidence of a direct effect of enalapril on the sympathetic nervous system or on PV.

A rapid glutamic decarboxylase test for identification of bacteria.

A simple rapid glutamic decarboxylase test is described. This test was found useful in the identification of Escherichia coli, Shigella sp., Providencia alcalifaciens, Clostridium perfringens and Bacteroides fragilis.

Long-term clinical course and symptomatic status of patients after operation for hypertrophic subaortic stenosis.

Long-term results of operation for IHSS were reviewed in 124 patients operated upon between 1960 and 1975. Most patients improved symptomatically and manifested marked reduction in LV outflow gradient at rest postoperatively. However, ten (8%) patients died of causes related to operation, 14 (12%) had persistent or recurrent severe functional limitation, and 11 (9%) died up to 13 years postoperatively due to hypertrophic cardiomyopathy. Overall annual mortality rate was 3.5% and was 1.8% for late deaths alone. Of 11 late postoperative deaths, six were sudden and five were due to chronic heart failure. Atrial fibrillation was significantly more common in patients who died late postoperatively than in survivors. Nine of the 11 late deaths had associated medical problems that may have contributed to their outcome. In conclusion, long-lasting clinical improvement occurred in most patients who survived operation for IHSS. However, 12% of patients deteriorated clinically over the 5.2 year average follow-up, and there is continued, small annual mortality.

Planar positron imaging of rubidium-82 for myocardial infarction: a comparison with thallium-201 and regional wall motion.

Rubidium-82 (Rb-82) is a generator-produced, short half-life (76 seconds) positron emitting potassium analog. Using a mobile gamma camera equipped with a rotating tungsten collimator and high-energy shielding, we examined the use of Rb-82 in the coronary care unit and clinical laboratory for detection of perfusion defects due to myocardial infarction. We studied 31 subjects, 10 patients with acute myocardial infarction, 12 with remote myocardial infarction, and nine controls. Rb-82 images were compared with Tl-201 and regional wall motion for detection of infarct-related arteries. Of the 22 patients with myocardial infarction, 16 were identified with Rb-82 and Tl-201. In nine control subjects, eight were normal with each method. Correlation between Rb-82 and Tl-201 defect scores was excellent. Sensitivity and specificity for infarct-related arteries were similar for Rb-82, Tl-201, and wall motion imaging. Thus planar Rb-82 imaging can detect MI reliably in the coronary care unit and in the clinical laboratory.