Sensitivity, specificity and predictive accuracy of Q wave, QX/QT ratio, QTc interval and ST depression during exercise testing in men with coronary artery disease.

One hundred forty-three subjects (107 with coronary artery disease [CAD], 23 without CAD [evaluated by coronary angiography] and 13 athletes) were selected for this study. All subjects underwent exercise testing to evaluate sensitivity, specificity and predictive value of Q wave, QX/QT ratio, QTc interval and ST depression. The Q-wave analysis revealed less sensitivity (49%) and less specificity (83%) than ST depression (71% and 97%, respectively). The QTc criterion had greater sensitivity (80%) than ST depression but less specificity (11%). The QX/QT criterion was no different in sensitivity (74%) but had less specificity (69%). To establish the statistical evaluation of the positive predictive value in CAD, variations in the prevalence of the disease were considered. A 90% prevalence gives the best positive predictive value on all evaluated measurements, between 100% for ST depression and 89% for the QTc criterion. A 5% prevalence, however, gives an acceptable positive predictive value only on ST-segment depression (57%).

Proliferation and apoptosis in a neuroblastoma cell line exposed to 900 MHz modulated radiofrequency field.

The aim of this study was to examine whether a modulated radiofrequency of the type used in cellular phone communications at a specific absorption rate (SAR) higher than International Commission on Non-ionizing Radiation Protection (ICNIRP) reference level for occupational exposure, could elicit alterations on proliferation, differentiation, and apoptosis processes in a neuroblastoma cell line. The cell line was exposed for 24, 48, and 72 h to 900 MHz radiofrequency and proliferation and differentiation were tested by WST-I assay and by a molecular analysis of specific markers, two oncogenes and a cytoskeleton protein, in exponential growth phase and in synchronized cell cultures. Apoptosis was evaluated by caspase activation analysis and by molecular detection of Poly (ADP-ribose) polimerase (PARP) cleavage. Combined exposures to radiofrequency and to the differentiative agent retinoic acid or to the apoptotic inducer camptothecin were carried out to test possible interference between electromagnetic field and chemical agents. Overall our data suggest that 900 MHz radiofrequency exposure up to 72 h does not induce significant alterations in the three principal cell activities in a neuroblastoma cell line.

Effect of captopril on blood pressure and on the renin-angiotensin-aldosterone system in coarctation of the aorta.

UNLABELLED: To investigate the role of the renin-angiotensin-aldosterone system in hypertension due to coarctation of the aorta (COA), upright mean arterial pressure (MAP), plasma renin activity (PRA) and plasma aldosterone (Aldo) were determined before and 90 minutes after a single oral dose of captopril (25 mg) in eight patients with COA and in fourteen with essential hypertension (EH). There was no significant difference in MAP, PRA or Aldo values between the two groups in baseline conditions. After captopril administration, MAP and Aldo decreased significantly in both groups (p less than 0.01), whereas PRA showed a marked increase in patients with COA (p less than 0.001) and no significant changes in EH patients (from 1.5 +/- 2.2 to 49.7 +/- 9.8 and from 5.6 +/- 0.9 to 8 +/- 1.5 ng/ml/3h respectively). CONCLUSIONS: 1) MAP reduction and marked renin increase after captopril in COA patients support the view that systemic hypertension in COA is, at least in part, renin mediated and 2) the evaluation of PRA after captopril could be helpful in the decision to proceed with more invasive procedures in patients with suspicious clinical features of COA or with residual post-coarctectomy hypertension.