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Nicorandil (N) and isosorbide dinitrate (ISDN) are vasodilator drugs used in patients with angina. In 24 healthy male volunteers (18-32 years), the acute effect of a single oral dose (20 mg) of N and ISDN on arterial diameter (D), distensibility, and compliance of the elastic common carotid artery (CCA) and the muscular femoral (FA) and brachial (BA) arteries were investigated. The effects on systolic and diastolic blood pressure (SBP, DBP), heart rate (HR), cardiac index (CI), systemic vascular resistance index (SVRI), and venous hemodynamics were also assessed. In addition, the subacute effects after 8 days of treatment with N (2 x 20 mg/day) and ISDN (3 x 20 mg/day) on these parameters were evaluated. After a 20 mg single oral dose, blood pressure decreased significantly more with ISDN (SBP: 6%; DBP: 14%) than with N (SBP: 2%; DBP: 6%), but after 8 days this decrease in blood pressure was not statistically different between ISDN and N. The diameter of CCA increased more with ISDN (11%) than N (5%) acutely as well as subacutely (ISDN: 12%; N: 9%). Heart rate increased only with ISDN (7% acutely, 3% subacutely). No differences between ISDN and nicorandil were found for acute and subacute effects on SVRI, venous hemodynamics, diameter of muscular arteries (FA, BA), and the distensibility and compliance of elastic (CCA) and muscular (FA, BA) arteries.(ABSTRACT TRUNCATED AT 250 WORDS)

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Doppler ultrasound may be a valuable tool in the estimation of fetal well-being. Nevertheless, a good understanding of the basic principles of ultrasound and the applied circuitry is necessary to obtain useful information. Some physical principles and limitations of ultrasound are discussed and the basics of the electronic devices are mentioned. Furthermore, the parameters used in obstetrical investigations are reviewed.

In 30 uncomplicated singleton pregnancies, varying in duration between 24 and 40 weeks, the variability of the flow velocity waveform (FVW) along the course of the umbilical artery was investigated. Blood flow velocities were recorded at 4 locations in the vessel: within the fetal abdomen, 0–5 cm from the origin of the umbilical cord, in the free-floating part, and 0–5 cm from its insertion in the placenta. From the Doppler signals recorded, the pulsatility index (PI) and a parameter for the frequency distribution index (FDI) were calculated. PI values differed among the locations, but no unequivocal tendency could be demonstrated. Statistical analysis, including multiple regression analysis for maternal and menstrual age and fetal heart rate, showed no significant difference in PI and FDI values for any of the 4 locations. It can be concluded that in uncomplicated pregnancies, possible changes in FVW (quantified by PI) along the course of the umbilical artery have no clinical relevance. Therefore, standardization for the sampling site when measuring PI in this vessel seems to be unnecessary.