Standard parameters of diabetic control: are they reliable?

To evaluate the reliability of the tradional methods to assess short-term control of diabetes, 25 children with insulin-dependent diabetes were studied with a 24-h glucose profile in addition to the traditional assessment techniques. Patient compliance was elminated as much as possible from the experimental design. The correlation of the routine methods with the 24-h glucose profile was excellent, and a scoring system for control was empirically derived. The single method of assessment that correlated best with the overall control score was the traditional daily urine test. In 6 of the 25 subjects studied, relative hypoglycemia was observed, occurring asymptomatically at night, and was followed by a hyperglycemic rebound. Traditional assessment techniques did not detect this event. Five additional patients had symptomatic daytime hypoglycemia. We conclude that the traditional daily urine tests are adquate indicators of day-to-day control in most diabetic patients, given adquate compliance. Our data also suggest that asymptomatic nocturnal hypoglycemia occurs frequently in children with diabetes, although clinical proof is difficult in the absence of a 24-h glucose profile.

Limitations of the electrocardiographic response to exercise in predicting coronary-artery disease

The electrocardiographic response to exercise was compared with the results of coronary angiography in 89 patients with Type II hyperlipoproteinemia who had previous myocardial infarction or typical angina or both (43 patients)(Group A), "atypical angina" (16 patients)(Group B)or positive electrocardiographic response to exercise without other evidence of cardiac disease (30 patients)(Group C). Thirty-nine of 43 in Group A had greater than or equal to 50 per cent stenosis, and 26 (67%) of these 39 had negative exercise tests. In Group B, five of the 16 had greater than or equal to 50% stenosis, and three had positive exercise tests (one patient had a false-positive test). In Group C, eleven of 30(37%) had greater than or equal to 50% stenosis; however, nine (30%) had minor stenosis (less than or equal to 50%), and 10(33%) normal coronary arteries. The diagnostic usefulness of exercise electrocardiography is limited. False-negative responses are frequent in patients with clinically suspected coronary disease, and false-positive responses frequent in asymptomatic patients.

Coronary artery disease in 116 kindred with familial type II hyperlipoproteinemia

Analysis of cardiovascular status in adult relatives of 116 kindred affected with familial hyperbetalipoproteinemia (type II hyperlipoproteinemia) was carried out to assess coronary artery disease (CAD) risk in relatives with type II (II) compared to unaffected family members. Over 90% of the 738 living relatives were interviewed by one investigator and 12 lead electrocardiograms were obtained. In these, and in 285 deceased relatives, physician and hospital records were utilized to determine CAD events by standard criteria. This study, the largest of its kind, permitted more precise and extensive determination of the CAD risk accompanying severe hyperbetalipoproteinemia than has heretofore been possible. CAD was diagnosed in 29.5% of II's compared with 10.5% of normal relatives (N) ( P < .001). The II's and N's did not differ significantly with regard to age distribution, sex, hypertension, smoking habits, or body mass index. According to the Rose questionnaire, angina pectoris was diagnosed in 21.8% of II's and 6.5% of N's ( P < .001). Documented myocardial infarction occurred in 6% of II's versus 1% of N's ( P = .002). CAD death or myocardial infarction occurred in 10.1% of II's compared with 1.8% of N's ( P < .001). The cumulative probability of nonfatal or fatal CAD by age 40 in male II's was 16% (1 in 6); by age 60, the expectation of an event had risen to 52% (1 in 2). Among male N's, the risk of nonfatal or fatal CAD by age 60 was 12.7%, lagging 20 years behind that seen in male II's. In female II's, the risk of nonfatal or fatal CAD by age 60 was 32.8% compared with only 9.1% in female N's.

Diphenylhydantoin in the prevention of recurring ventricular tachycardia

The efficacy of diphenylhydantoin in preventing recurrent ventricular tachycardia was studied in ten patients, nine of whom had documented coronary heart disease. Prolonged continuous ECG monitoring of up to 72 hr was performed in each case. Oral and intravenous loading doses of 1000 to 1500 mg were given on the first day of therapy to insure rapid attainment of therapeutic blood levels. Diphenylhydantoin was uniformly ineffective in preventing recurrence of ventricular tachycardia despite the presence of what is regarded as adequate therapeutic plasma concentrations (greater than 19.0 µg/ml in five patients, 10.8-18.0 µg/ml in the remaining five) shortly after onset of ventricular tachycardia. Nystagmus was noted in eight patients, but plasma diphenylhydantoin levels varied widely (8.6-35.0 µg/ml) when this sign of neurotoxicity was first detected.

Purification of pig renin

1. A new method of purification of renin is described. This method employs the following procedures: ethanol precipitation; saline extraction; precipitation of renin with 40% ammonium sulphate; precipitation of impurities with 3% ammonium sulphate at pH2.5; chromatography on DEAE-cellulose and CM-Sephadex; gel filtration on Sephadex G-100 (both normal and superfine grade); finally, starch-gel electrophoresis. 2. The final renin preparation had a specific activity 10(4) times that of the initial saline extract. 3. A single band of stained protein corresponding to the renin activity was present on starch-gel electrophoresis in the final step and a single precipitin line was obtained to this material with rabbit anti-(pig renin) serum. 4. Double diffusion in agar with rabbit anti-(pig renin) serum showed one major precipitin line, probably due to renin-anti-renin complex, and in addition two minor components.