To investigate the effects of age on thermal sensitivity, preferred ambient temperature (Tpref) was compared between old (71-76 years) and young (21-30 years) groups, each consisting of six male subjects in summer and winter. The air temperature (Ta) was set at either 20 degrees C or 40 degrees C at commencement. The subject was directed to adjust the Ta for 45 min by manipulating a remote control switch to the level at which he felt most comfortable. In the older group, the Tpref was significantly lower in trails starting at 20 degrees C than that starting at 40 degrees C in summer. The fluctuation of Tpref (temperature difference between maximum and minimum Ta during the last 10 min) was significantly wider in the older group in both summer and winter. Repetition of the same experiment on each subject showed a poorer reproducibility of Tpref in the older group than in the younger group in summer. Tympanic and esophageal temperatures of the older group kept falling throughout the trial starting at 20 degrees C in summer. These results suggest that thermal sensitivity is decreased with advancing age and that thermal perception in the elderly, especially to cold, is less sensitive in summer.

To examine whether cutaneous active vasodilatation is mediated by sudomotor nerve fibres we recorded cutaneous blood flow and sweat rates continuously with laser-Doppler flowmetry and capacitance hygrometry, respectively, from the dorsal and plantar aspects of the foot in 11 male subjects at varying ambient temperatures (Ta) between 22 and 40 degrees C (relative humidity 40%). In a warmer environment (Ta 29-40 degrees C), predominant responses of the blood flow curve from the sole of the foot were transient depressions (negative blood flow responses, NBR), whereas those from the dorsal foot were transient increases (positive blood flow responses, PBR). The PBR on the dorsal foot occurred spontaneously or in response to mental or sensory stimuli, and when PBR did not fuse with each other the rate of PBR was linearly related to tympanic temperature. When dorsal foot sweating was continuous, PBR on the dorsal foot almost entirely synchronized with sweat expulsion. When dorsal foot sweating was intermittent PBR sometimes occurred on the dorsal foot without corresponding sweat expulsions, but these PBR showed a complete correspondence with subthreshold sweat expulsion seen on a methacholine-treated area. The amplitude and the duration of PBR showed a significant linear relationship with the amplitude and the duration of the corresponding sweat expulsion. In a thermoneutral or cooler environment (Ta 22-29 degrees C), PBR occurred on the sole of the foot when mental or sensory stimuli elicited sweating in that area. Thus, PBR occurred when and where sweating appeared. Atropine failed to abolish PBR on the dorsal foot. Blockade of the peroneal nerve eliminated both PBR and NBR on the dorsal foot.(ABSTRACT TRUNCATED AT 250 WORDS)

The home-visit program conducted once or twice by public health nurses or trained community staff for mothers with infants showed no substantial reduction in maternal stress and no increase in social trust.

We have examined the nonparallel changes in tympanic membrane temperatures (Tty) from the two ears in response to various changes in body and head positions. Upon assuming a lateral recumbent position, the Tty on the lower side increased while that on the upper side decreased. Pressure application over a wide area of the lateral chest only caused inconsistent and obscure asymmetric changes in Tty. A lateral flexion of the head with the subject sitting upright and a rotation of the head to the side in a supine position induced an increase in the Tty on the lower side compared to that on the upper side. The temperature and blood flow of the forehead often decreased on the lower side and increased on the upper side, although such responses were not always concomitant with the asymmetric changes in Tty. A dorsal flexion of the head with the subject in a reclining position caused a slight increase in the Tty, whereas raising the head upright induced a slight decrease in them. Two additional experiments were carried out with single photon emission computed tomography using 99mTc-hexamethylpropyleneamine oxime as tracer, and a slight, relative decrease in counts was noted in the right hemisphere during rotation of the head to the right. These results would strongly suggest that unilateral increases and decreases in Tty could have been caused by one-sided decreases and increases, respectively, in blood flow to the brain and/or the tympanic membrane, induced by a vasomotor reflex involving vestibular stimulation.