We investigated the changes in the cardiovascular system [resting blood pressure (BP) and heart rate (HR), measured by means of a 24-h ambulatory BP and a holter-electrocardiogram (ECG)], glycemic parameters, and lipid metabolism of subjects suffering from metabolic syndrome during a 3-week sojourn at 1,700 m in the Austrian Alps. A total of 22 male subjects with metabolic syndrome were selected. Baseline investigations were performed at Innsbruck (500 m above sea level). During the 3-week altitude stay the participants simulated a holiday with moderate sports activities. Examinations were performed on days 1, 4, 9, and 19. After returning to Innsbruck, post-altitude examinations were conducted after 7-10 days and 6-7 weeks, respectively. The 24-h ambulatory BP and holter ECG revealed a decrease in average HR, BP, and rate pressure product (RPP: systolic blood pressure x HR) after 3 weeks of altitude exposure. In some patients, an increase in premature ventricular beats was observed at the end compared to the beginning of the exposure to moderate altitude. The ECG revealed no ischemic ST-segment changes. Maximal physical capacity as measured by symptom-limited maximal cycle ergometry tests remained unchanged during the study. Six weeks after the altitude exposure the blood pressure increased again and returned to pretest levels. The Homeostasis Model Assessment index, which is a measure of insulin resistance, decreased significantly and glucose concentrations obtained after an oral glucose tolerance test were significantly lower after the stay at altitude compared to the basal values. We conclude that after a 3-week exposure to moderate altitude, patients with metabolic syndrome (1) tolerated their sojourn without any physical problems, (2) exhibited short-term favorable effects on the cardiovascular system, and (3) had significant improvements in glycemic parameters that were paralleled by a significant increase in high-density-lipoprotein-cholesterol.

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Adrenaline and noradrenaline concentrations in arterial and simultaneously collected "arterialised" capillary plasma (vasodilated ear-lobe) obtained from unmedicated resting subjects (n = 9) were measured radio-enzymatically and found to be indistinguishable (adrenaline: 112 +/- 42 ng/l versus 109 +/- 52 ng/l; noradrenaline: 378 +/- 174 ng/l versus 410 +/- 219 ng/l; mean +/- SD; paired t-test: P greater than 0.10). The fitted regression lines did not differ significantly from the line of identity (slope = 1). The correlation coefficient was 0.969 for adrenaline and 0.945 for noradrenaline. Adrenaline and noradrenaline concentrations in plasma from freely flowing capillary blood (non-hyperaemic fingertip) were very similar to those in arterial plasma (adrenaline: 101 +/- 89 ng/l versus 90 +/- 72 ng/l;noradrenaline: 399 +/- 240 ng/l versus 395 +/- 240 ng/l; n = 13 each; paired t-test: P greater than 0.10). The correlation coefficient was 0.981 and 0.917 for adrenaline and noradrenaline, respectively. Adrenaline concentrations in capillary plasma (vasodilated earlobe), however, were significantly higher than those in venous (forearm) plasma (100 +/- 51 ng/l versus 61 +/- 23 ng/l; n = 15; P less than 0.01; capillary-venous difference = 35 +/- 18%) while noradrenaline concentrations did not differ significantly. We conclude that capillary plasma resembles arterial plasma in its catecholamine content and we show that arterial catecholamine levels may be determined in capillary, especially "arterialised" specimens, eliminating the need for arterial blood sampling.

P6vices for hydrodynamic simulation are required in a variety of studies such as device evaluation, cardiovascular modeling and for student training. Most studies today use different, incompatible circuits, which must be redesigned for every new application. To obtain a universal apparatus, a unitized system with standard connectors was developed. Three types of connectors were selected: 1" flange connectors, 1/2" tubing connectors and Luer-connectors with a 2 mm lumen. The complete system consists of reservoirs, throttles, valve holders, adapters for Doppler ultrasound probes, and converters to link these basic diameters. The apparatus can be driven by membrane, centrifugal and geared pumps. The system has successfully been used in echocardiographic studies of stenosis and valvular insufficiency, for pulse propagation in vascular grafts, and to test the hydraulic performance of cardiac assist devices. Flow rates between 0.1 and 30 l/min and pressure gradients up to 250 mmHg were achieved. In practical use, the system can be adapted to suit various investigations, with minimal expense. Standardization of the parts and connectors results in simple documentation and good reproducibility.

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