No abstract

A case of two nontwin brothers, 19 and 17 years old, who had both Klinefelter's syndrome with a chromosomal mosaicism 46 XY/47 XXY, is reported here. The analysis of their mother's karyotype revealed a 46 XX/47 XXX mosaicism. It is hypothesized that the presence of an extra X chromosome in all three subjects could depend on the transmission of two X chromosomes from the mother to the sons or, less likely, on an increased liability to nondisjunction of the X chromosomes during one of the early mitotic divisions in the zygotes.

The aim of our study was to investigate the effect of a new controlled-release (Durules) formulation of isosorbide-5-mononitrate (IS5MN) in association with ß-blockers or calcium antagonists in stable effort angina pectoris. Twelve patients with stable angina, a positive treadmill test and angiographically documented coronary artery disease were enrolled. In a randomized, doubleblind, crossover fashion, patients underwent a clinical and ergometrie evaluation 2 and 9 h after the drug administration on both the 2nd and 14th day of two 14-day-periods. In comparison to placebo, controlled-release (Durules) IS5MN increased time to 1 mm ST segment depression both during acute (389.5 ± 37 vs. 371.3 ± 34.5 s at the 2nd hour; 384 ± 22.5 vs. 319.8 ± 32.7 s, p < 0.05 at the 9th hour) and sustained administration (434.4 ± 33.4 vs. 346.7 ± 26.6 s, p<0.05 at the 2nd hour; 419.7 ± 45.6 vs. 331.4 ± 26.1 s, p<0.05 at the 9th hour). A similar effect was observed with the time to ECG normalization in the recovery, both acutely (362 ± 52.8 vs. 330 ± 53.5 s at the 2nd hour; 325 ± 47.7 vs. 390 ± 52 s, p < 0.05 at the 9th hour) and chronically (265 ± 44 vs. 365 ± 53 s, p < 0.05 at the 2nd hour, 320 ±51.3 vs. 405 ± 57.5 s, p < 0.05 at the 9th hour). Controlled-release (Durules) IS5MN is effective in association with calcium antagonists or ß-blockers, in delaying the appearance of myocardial ischemia on effort and in shortening the duration of ischemia after the cessation of exercise. These effects are present both during short- and long-term administration, suggesting that the kinetic peculiarities of this formulation are capable of preventing tolerance development.