Zengyong Li et al 2006 Phys. Med. Biol. 51 2681 doi:10.1088/0031-9155/51/10/020
Zengyong Li1, Eric W C Tam1, Maggie P C Kwan1, Arthur F T Mak1, Samuel C L Lo2 and Mason C P Leung3
Show affiliationsThe objective of this study is to assess the effect of prolonged surface compression on the skin blood flowmotion in rats using spectral analysis based on wavelets transform of the periodic oscillations of the cutaneous laser Doppler flowmetry (LDF) signal. An external pressure of 13.3 kPa (100 mmHg) was applied to the trochanter area and the distal lateral tibia of Sprague-Dawley rats via two specifically designed pneumatic indentors. The loading duration was 6 hours/day for 4 consecutive days. Five frequency intervals were identified (0.01–0.04 Hz, 0.04–0.15 Hz, 0.15–0.4 Hz, 0.4–2 Hz and 2–5 Hz) corresponding to endothelial related metabolic, neurogenic, myogenic, respiratory and cardiac origins. The absolute amplitude of oscillations of each particular frequency interval and the normalized amplitude were calculated for quantitative assessments. The results showed that (1) tissue compression following the above schedule induced significant decrease in the normalized amplitude in the frequency interval of 0.01–0.04 Hz both in the trochanter area (p < 0.001) and tibialis area (p = 0.023), (2) prolonged compression induced significant increase in the absolute amplitude (p = 0.004 for the trochanter area and p = 0.017 for the tibialis area) but significant decrease in the normalized amplitude (p = 0.023 for the trochanter area and p = 0.026 for the tibialis area) in the frequency interval of 0.15–0.4 Hz, and (3) at the tibialis area, the flowmotion amplitude (frequency interval 0.15–0.4 Hz) measured prior to the daily tissue compression schedule was found to be significantly higher on day 4 than the measurements obtained on day 1. However, this finding was not observed at the trochanter area. Our results suggested that prolonged compression might induce endothelial damage and affect the endothelial related metabolic activities.
47.63.-b Biological fluid dynamics
Issue 10 (21 May 2006)
Received 1 December 2005
Published 4 May 2006
Zengyong Li et al 2006 Phys. Med. Biol. 51 2681
K M Langen et al 2003 Phys. Med. Biol. 48 1345
M A Moore and C A Wilson 1980 J. Phys. A: Math. Gen. 13 3501
Lin Jian et al 2007 Chinese Phys. Lett. 24 3280
Isobel C Walker et al 1996 J. Phys. B: At. Mol. Opt. Phys. 29 4749
Benjamin D. G. Chandran and Jason L. Maron 2004 ApJ 602 170
Colin Aspin et al. 2008 The Astronomical Journal 135 423
A Gasmi et al 2009 J. Phys. D: Appl. Phys. 42 225408
T Padmanabhan 2002 Class. Quantum Grav. 19 L167
A. J. Barger et al. 2005 The Astronomical Journal 129 578