Object To knowhow Japanese patients perceive their physicians without a white coat during consultations. Subjects and MethodsThe patients whovisited a university clinic were divided into two groups: those seen by a physician in a white coat (the white-coat group) and those seen by a physician in private clothes (the private-clothes group). Questionnaires were distributed to the patients, which asked the tension and satisfaction of consultations as well as their preference for physician's attire. The answers of the white-coat group were comparedwith those of the privateclothes group. Results The percentage of new patients whofelt tense during consultations was greater in the white-coat group (42%) than in the private-clothes group (33%). Seventy-one percent of the patients in the white-coat group preferred physicians in a white coat whereas only 39 % preferred so in the private-clothes group (p<0.0001). However, the degree of patients' satisfaction for the consultation showed no statistical difference between the groups. Sixty-nine percent of the patients older than or equal to 70 years preferred a white coat while 52 percent of the patients younger than 70 years preferred so (p=0.002). Conclusion Physician's white coats did not in fluence the satisfaction with the consultations for most Japanese patients in a university clinic, although elderly patients as well as those seen by a physician in a white coat tended to prefer the white coat to the private clothes. Furthermore, practice without a white coat might reduce patients' tension during their first consultation. (Internal Medicine 38: 533-536, 1999)

The hypothesis was tested that narrowing of arterial pulse pressure (PP) is a determinant of arginine vasopressin (AVP) release in humans. Six normal males completed a two-step lower body negative pressure (LBNP) protocol of -20 and -50 mmHg, respectively, for 10 min each. None of these subjects experienced presyncopal symptoms. Arterial plasma AVP and plasma renin activity (PRA) (at 2-min intervals) only increased subsequent to a decrease in PP (invasive brachial arterial measurements) and stroke volume (ultrasound Doppler technique, n = 4). Simultaneously, mean arterial pressure did not change. A selective decrease in central venous pressure and left atrial diameter (echocardiography, n = 4) at LBNP of -20 mmHg did not affect AVP or PRA, whereas arterial plasma norepinephrine increased (n = 4). During LBNP, significant (P < 0.05) intraindividual linear correlations were observed between log(AVP) and PP in four of the subjects with r values from -0.75 to -0.99 and between log(PRA) and PP in all six subjects with r values from -0.89 to -0.98. In conclusion, these results are in compliance with the hypothesis that narrowing of PP in humans during central hypovolemia is a determinant of AVP and renin release.

Changes in plasma volume (PV) throughout 12 h of thermoneutral (34.5 degrees C) water immersion (WI) were evaluated in eight subjects by an improved Evans blue (EB) technique and by measurements of hematocrit (Hct), hemoglobin (Hb), and plasma protein concentrations (Pprot). Appropriate time control studies (n = 6) showed no measurable change in PV. At 30 min of immersion, EB measurements demonstrated an increase in PV of 16 +/- 2% (457 +/- 70 ml). Calculations, however, based on concomitant changes in Hct, Hb, and Pprot showed an increase in PV of only 6.9 +/- 0.9 to 10.0 +/- 0.8% at 30 min of WI. PV values based on EB measurements subsequently declined throughout WI to (but not below) the preimmersion level. Concomitantly, changes in PV calculated from Pprot values remained increased, whereas estimations of changes in PV based on Hct and Hb values returned to prestudy levels after 4 h of immersion. It is concluded that PV initially increases by 16 +/- 2% during WI and does not decline below preimmersion and control levels during 12 h of immersion despite a loss of 0.9 +/- 0.2 liter of body fluid. Furthermore, changes in Hct, Hb, and Pprot do not provide accurate measures of the changes in PV during WI in humans.

To investigate the influence of carotid baroreflexes on plasma arginine vasopressin (AVP) in humans, eight healthy males underwent two sessions of passive head-up tilt to 60 degrees for 15 min each. During one of the sessions (sequence randomized), carotid baroreflexes were simultaneously stimulated by static neck suction of 23 +/- 1 mmHg during the whole period of head-up tilt. Only subjects who did not develop presyncopal symptoms during head-up tilt were included. Head-up tilt increased AVP significantly from 1.0 +/- 0.3 to 4.2 +/- 1.3 pg/ml (P less than 0.05). In contrast to this, AVP did not at any point in time increase significantly during head-up tilt when neck suction was applied. Plasma renin activity and heart rate were unaffected by neck suction, whereas mean arterial pressure and central venous pressure decreased. We conclude that the moderate but significant increase in plasma AVP during nonhypotensive head-up tilt is in part mediated by deloading of carotid baroreceptors induced by the acute fall in hydrostatic pressure at the level of the carotid sinus.

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