Context: Low current intensity iontophoresis treatments have increased skin perfusion over 700% from baseline potentially altering drug clearance from or diffusion to the targeted area. Objective: To determine the effects of a preceding 10-minute ice massage on subcutaneous dexamethasone sodium phosphate (Dex-P) concentration and skin perfusion during and after a 4-mA iontophoresis treatment. Design: Controlled laboratory study. Setting: Research laboratory. Patients or Other Participants: Twenty-four participants (male = 12, female = 12; age = 25.6 [4.5] y, height = 173.9 [8.51] cm, mass = 76.11 [16.84] kg). Intervention(s): Participants were randomly assigned into 2 groups: (1) pretreatment 10-minute ice massage and (2) no pretreatment ice massage. Treatment consisted of an 80-mA·minute (4 mA, 20 min) Dex-P iontophoresis treatment. Microdialysis probes (3 mm deep in the forearm) were used to assess Dex-P, dexamethasone (Dex), and its metabolite (Dex-Met) concentrations. Skin perfusion was measured using laser Doppler flowmetry. Main Outcome Measure(s): Microdialysis samples were collected at baseline, at conclusion of treatment, and every 20 minutes posttreatment for 60 minutes. Samples were analyzed to determine Dex-Total (Dex-Total = Dex-P + Dex + Dex-Met). Skin perfusion was calculated as a percentage change from baseline. A mixed-design analysis of variance was used to determine Dex-Total and skin perfusion difference between groups overtime. Results: There was no difference between groups (P = .476), but [Dex-Total] significantly increased over the course of the iontophoresis and posttreatment time (P < .001). Dex-P was measured in 18 of 24 participants with a mean concentration of 0.67 (1.09) μg/mL. Skin perfusion was significantly greater in the no ice treatment group (P = .002). Peak skin perfusion reached 27.74% (47.49%) and 117.39% (103.45%) from baseline for the ice and no ice groups, respectively. Conclusions: Ice massage prior to iontophoresis does not alter the tissue [Dex-Total] even with less skin perfusion.
Brady M. Smith, David O. Draper, Robert D. Hyldahl and Justin H. Rigby
Jennifer Zink, David A. Berrigan, Miranda M. Broadney, Faizah Shareef, Alexia Papachristopoulou, Sheila M. Brady, Shanna B. Bernstein, Robert J. Brychta, Jacob D. Hattenbach, Ira L. Tigner Jr., Amber B. Courville, Bart E. Drinkard, Kevin P. Smith, Douglas R. Rosing, Pamela L. Wolters, Kong Y. Chen, Jack A. Yanovski and Britni R. Belcher
Purpose: Sedentary time relates to higher anxiety and more negative affect in children. This study assessed whether interrupting sitting over 3 hours is sufficient to influence state anxiety, positive affect, or negative affect, and tested weight status as a moderator. Methods: Analyses were the second (preplanned) purpose of a larger study. Children (N = 61; age: mean [SD] = 9.5 [1.3]; 43% healthy weight) completed 2 experimental conditions: continuous sitting for 3 hours and sitting for 3 hours interrupted with walking for 3 minutes in every 30 minutes. State anxiety, positive affect, and negative affect were reported at pretest and posttest. Multilevel models for repeated measures assessed whether experimental condition predicted posttest scores. Results: Experimental condition was unrelated to posttest state anxiety or positive affect. Weight status moderated how experimental condition influenced posttest negative affect (P = .003). Negative affect was lower in the children of healthy weight after interrupted sitting (vs continuous sitting; β = −0.8; 95% confidence interval, −1.5 to 0.0, P = .05), but it was higher in the children with overweight/obesity after interrupted sitting (vs continuous sitting; β = 0.6; 95% confidence interval, 0.0 to 1.2, P = .06). Conclusions: Interrupting sitting acutely reduced negative affect in children of healthy weight, but not in children with overweight. Further research is needed to better understand the potential emotional benefits of sitting interruptions in youth.