Repetition time was every 60 seconds, with each scan being accomplished in Birinapant about 40 seconds. The central well of the custom-made chamber was filled to the rim with isotonic saline and overlaid with a transparent glass cover slip. The skin underneath the cover slip and water was thus accessible to the laser light (as in our previous study [3]). The commercial chamber was just overlaid with a transparent glass cover slip and not filled with liquid, because it was not water-resistant. For the measurements with the LDF device, probes were fitted into either a custom-made or a commercial chamber. An adaptator was required

to hold the PF408 probe in the custom-made chamber (Figure 1C). In preliminary experiments, a small-size thermistor (length and diameter of 0.3 cm and 0.01 cm,

calibrated with a mercury thermometer) BMN 673 nmr was used to check the skin temperature underneath each chamber at settings of 34°C and 41°C. This thermistor (custom prepared from a recycled 2F Swan-Ganz catheter, Edwards, Irvine, United States) was placed between the skin and the double-sided tape within a tad of heat-conducting paste. The sequence for inducing thermal hyperemia was as follows. The temperature was set at 34°C during about three minutes to ensure thermal stability. Then, SkBF was recorded for five minutes at 34°C, after which the temperature was raised to 41°C and maintained at this level for the next 30 minutes [3]. The time required to reach the final temperature was slightly shorter with the commercial (30 seconds) than with the custom-made system (60 seconds). This difference between devices was inherent to their design and thus could not be avoided. Protocol.  The experiment was completed in a single visit. The subjects were examined in a quiet room

with an ambient temperature ranging from 21 to 25°C (systematically controlled and kept in that range with air conditioning). The ambient light this website level was daylight with the blinds half pulled down and artificial light turned off to avoid any confounding of laser-Doppler measurements by changes in background lighting levels [6]. The volunteers reported to the laboratory at 1:30 pm. They had abstained from caffeine-containing beverages since the night before the experiment, had taken a lunch two hours before the study, had been instructed to avoid exposing themselves to important physical exercise, mental stress, or changes in ambient temperature, just before the beginning of the study. Their weight and height were measured on arrival. Body temperature was taken with an ear thermometer (ThermoScan Braun, Switzerland). Forearm skin temperature was obtained with the thermistor described above near the sites of SkBF measurement. The arm circumference was taken too, to choose a cuff of the right size for the oscillometric measurement of blood pressure and heart rate (StabiloGraph, IEM, Deutschland).