The Experts below are selected from a list of 96 Experts worldwide ranked by ideXlab platform
Dick H J Thijssen - One of the best experts on this subject based on the ideXlab platform.
-
impact of retrograde shear rate on brachial and superficial Femoral Artery Flow mediated dilation in older subjects
Atherosclerosis, 2015Co-Authors: Tim H A Schreuder, Daniel J Green, Maria T E Hopman, Dick H J ThijssenAbstract:An inverse, dose-dependent relationship between retrograde shear rate and brachial Artery endothelial function exists in young subjects. This relationship has not been investigated in older adults, who have been related to lower endothelial function, higher resting retrograde shear rate and higher risk of cardiovascular disease. Aim To investigate the impact of a step-wise increase in retrograde shear stress on Flow-mediated dilation in older males in the upper and lower limbs. Methods Fifteen older (68±9 years) men reported to the laboratory 3 times. We examined brachial Artery Flow-mediated dilation before and after 30-minutes exposure to cuff inflation around the forearm at 0, 30 and 60 mmHg, to manipulate retrograde shear rate. Subsequently, the 30-minute intervention was repeated in the superficial Femoral Artery. Order of testing (vessel and intervention) was randomised. Results Increases in cuff pressure resulted in dose-dependent increases in retrograde shear in both the brachial and superficial Femoral Artery in older subjects. In both the brachial and the superficial Femoral Artery, no change in endothelial function in response to increased retrograde shear was observed in older males (‘time’ P=0.274, ‘cuff*time P=0.791’, ‘cuff*Artery*time P=0.774’). Conclusion In contrast with young subjects, we found that acute elevation in retrograde shear rate does not impair endothelial function in older humans. This may suggest that subjects with a priori endothelial dysfunction are less responsive or requires a larger shear rate stimulus to alter endothelial function.
-
acute impact of retrograde shear rate on brachial and superficial Femoral Artery Flow mediated dilation in humans
Physiological Reports, 2014Co-Authors: Tim H A Schreuder, Daniel J Green, Maria T E Hopman, Dick H J ThijssenAbstract:Retrograde shear rate (SR) in the brachial Artery (BA) is associated with endothelial dysfunction; a precursor to atherosclerosis. The BA does not typically manifest clinical atherosclerosis, whereas the superficial Femoral Artery (SFA) is more prone to developing plaque. Examine whether the impact of incremental levels of retrograde SR differs between atherosclerosis-prone (i.e., SFA) and -resistant vessels (i.e., BA) in healthy men. Thirteen healthy young men reported three times to the laboratory. We examined BA Flow-mediated dilation (FMD) before and after 30-min exposure to cuff inflation around the forearm at 0, 30, and 60 mmHg, to manipulate retrograde SR. Subsequently, the 30-min intervention was repeated in the SFA, using the same cuff pressure as in the forearm. Order of testing (vessel and intervention) was randomized among subjects. We found a dose-dependent increase in retrograde SR with 30 and 60 mmHg cuff inflation, which was present in both the BA and SFA (all P < 0.05). BA and SFA FMD decreased after the 30-min intervention (“time”: P = 0.012), and this was dependent on cuff pressure (“cuff 9 time”: P = 0.024). A significant decrease in FMD was observed after 60 mmHg only and this change was similarly present in both arteries (“time 9 Artery”: P = 0.227). Moreover, the BA and SFA demonstrate a similar relationship between changes in retrograde SR and FMD (r = 0.498 and 0.475, respectively). Our study demonstrates that acute exposure to an increase in retrograde shear leads to comparable decreases in FMD in atherosclerotic-prone and -resistant conduit arteries in humans.
Daniel J Green - One of the best experts on this subject based on the ideXlab platform.
-
impact of retrograde shear rate on brachial and superficial Femoral Artery Flow mediated dilation in older subjects
Atherosclerosis, 2015Co-Authors: Tim H A Schreuder, Daniel J Green, Maria T E Hopman, Dick H J ThijssenAbstract:An inverse, dose-dependent relationship between retrograde shear rate and brachial Artery endothelial function exists in young subjects. This relationship has not been investigated in older adults, who have been related to lower endothelial function, higher resting retrograde shear rate and higher risk of cardiovascular disease. Aim To investigate the impact of a step-wise increase in retrograde shear stress on Flow-mediated dilation in older males in the upper and lower limbs. Methods Fifteen older (68±9 years) men reported to the laboratory 3 times. We examined brachial Artery Flow-mediated dilation before and after 30-minutes exposure to cuff inflation around the forearm at 0, 30 and 60 mmHg, to manipulate retrograde shear rate. Subsequently, the 30-minute intervention was repeated in the superficial Femoral Artery. Order of testing (vessel and intervention) was randomised. Results Increases in cuff pressure resulted in dose-dependent increases in retrograde shear in both the brachial and superficial Femoral Artery in older subjects. In both the brachial and the superficial Femoral Artery, no change in endothelial function in response to increased retrograde shear was observed in older males (‘time’ P=0.274, ‘cuff*time P=0.791’, ‘cuff*Artery*time P=0.774’). Conclusion In contrast with young subjects, we found that acute elevation in retrograde shear rate does not impair endothelial function in older humans. This may suggest that subjects with a priori endothelial dysfunction are less responsive or requires a larger shear rate stimulus to alter endothelial function.
-
acute impact of retrograde shear rate on brachial and superficial Femoral Artery Flow mediated dilation in humans
Physiological Reports, 2014Co-Authors: Tim H A Schreuder, Daniel J Green, Maria T E Hopman, Dick H J ThijssenAbstract:Retrograde shear rate (SR) in the brachial Artery (BA) is associated with endothelial dysfunction; a precursor to atherosclerosis. The BA does not typically manifest clinical atherosclerosis, whereas the superficial Femoral Artery (SFA) is more prone to developing plaque. Examine whether the impact of incremental levels of retrograde SR differs between atherosclerosis-prone (i.e., SFA) and -resistant vessels (i.e., BA) in healthy men. Thirteen healthy young men reported three times to the laboratory. We examined BA Flow-mediated dilation (FMD) before and after 30-min exposure to cuff inflation around the forearm at 0, 30, and 60 mmHg, to manipulate retrograde SR. Subsequently, the 30-min intervention was repeated in the SFA, using the same cuff pressure as in the forearm. Order of testing (vessel and intervention) was randomized among subjects. We found a dose-dependent increase in retrograde SR with 30 and 60 mmHg cuff inflation, which was present in both the BA and SFA (all P < 0.05). BA and SFA FMD decreased after the 30-min intervention (“time”: P = 0.012), and this was dependent on cuff pressure (“cuff 9 time”: P = 0.024). A significant decrease in FMD was observed after 60 mmHg only and this change was similarly present in both arteries (“time 9 Artery”: P = 0.227). Moreover, the BA and SFA demonstrate a similar relationship between changes in retrograde SR and FMD (r = 0.498 and 0.475, respectively). Our study demonstrates that acute exposure to an increase in retrograde shear leads to comparable decreases in FMD in atherosclerotic-prone and -resistant conduit arteries in humans.
Tim H A Schreuder - One of the best experts on this subject based on the ideXlab platform.
-
impact of retrograde shear rate on brachial and superficial Femoral Artery Flow mediated dilation in older subjects
Atherosclerosis, 2015Co-Authors: Tim H A Schreuder, Daniel J Green, Maria T E Hopman, Dick H J ThijssenAbstract:An inverse, dose-dependent relationship between retrograde shear rate and brachial Artery endothelial function exists in young subjects. This relationship has not been investigated in older adults, who have been related to lower endothelial function, higher resting retrograde shear rate and higher risk of cardiovascular disease. Aim To investigate the impact of a step-wise increase in retrograde shear stress on Flow-mediated dilation in older males in the upper and lower limbs. Methods Fifteen older (68±9 years) men reported to the laboratory 3 times. We examined brachial Artery Flow-mediated dilation before and after 30-minutes exposure to cuff inflation around the forearm at 0, 30 and 60 mmHg, to manipulate retrograde shear rate. Subsequently, the 30-minute intervention was repeated in the superficial Femoral Artery. Order of testing (vessel and intervention) was randomised. Results Increases in cuff pressure resulted in dose-dependent increases in retrograde shear in both the brachial and superficial Femoral Artery in older subjects. In both the brachial and the superficial Femoral Artery, no change in endothelial function in response to increased retrograde shear was observed in older males (‘time’ P=0.274, ‘cuff*time P=0.791’, ‘cuff*Artery*time P=0.774’). Conclusion In contrast with young subjects, we found that acute elevation in retrograde shear rate does not impair endothelial function in older humans. This may suggest that subjects with a priori endothelial dysfunction are less responsive or requires a larger shear rate stimulus to alter endothelial function.
-
acute impact of retrograde shear rate on brachial and superficial Femoral Artery Flow mediated dilation in humans
Physiological Reports, 2014Co-Authors: Tim H A Schreuder, Daniel J Green, Maria T E Hopman, Dick H J ThijssenAbstract:Retrograde shear rate (SR) in the brachial Artery (BA) is associated with endothelial dysfunction; a precursor to atherosclerosis. The BA does not typically manifest clinical atherosclerosis, whereas the superficial Femoral Artery (SFA) is more prone to developing plaque. Examine whether the impact of incremental levels of retrograde SR differs between atherosclerosis-prone (i.e., SFA) and -resistant vessels (i.e., BA) in healthy men. Thirteen healthy young men reported three times to the laboratory. We examined BA Flow-mediated dilation (FMD) before and after 30-min exposure to cuff inflation around the forearm at 0, 30, and 60 mmHg, to manipulate retrograde SR. Subsequently, the 30-min intervention was repeated in the SFA, using the same cuff pressure as in the forearm. Order of testing (vessel and intervention) was randomized among subjects. We found a dose-dependent increase in retrograde SR with 30 and 60 mmHg cuff inflation, which was present in both the BA and SFA (all P < 0.05). BA and SFA FMD decreased after the 30-min intervention (“time”: P = 0.012), and this was dependent on cuff pressure (“cuff 9 time”: P = 0.024). A significant decrease in FMD was observed after 60 mmHg only and this change was similarly present in both arteries (“time 9 Artery”: P = 0.227). Moreover, the BA and SFA demonstrate a similar relationship between changes in retrograde SR and FMD (r = 0.498 and 0.475, respectively). Our study demonstrates that acute exposure to an increase in retrograde shear leads to comparable decreases in FMD in atherosclerotic-prone and -resistant conduit arteries in humans.
Maria T E Hopman - One of the best experts on this subject based on the ideXlab platform.
-
impact of retrograde shear rate on brachial and superficial Femoral Artery Flow mediated dilation in older subjects
Atherosclerosis, 2015Co-Authors: Tim H A Schreuder, Daniel J Green, Maria T E Hopman, Dick H J ThijssenAbstract:An inverse, dose-dependent relationship between retrograde shear rate and brachial Artery endothelial function exists in young subjects. This relationship has not been investigated in older adults, who have been related to lower endothelial function, higher resting retrograde shear rate and higher risk of cardiovascular disease. Aim To investigate the impact of a step-wise increase in retrograde shear stress on Flow-mediated dilation in older males in the upper and lower limbs. Methods Fifteen older (68±9 years) men reported to the laboratory 3 times. We examined brachial Artery Flow-mediated dilation before and after 30-minutes exposure to cuff inflation around the forearm at 0, 30 and 60 mmHg, to manipulate retrograde shear rate. Subsequently, the 30-minute intervention was repeated in the superficial Femoral Artery. Order of testing (vessel and intervention) was randomised. Results Increases in cuff pressure resulted in dose-dependent increases in retrograde shear in both the brachial and superficial Femoral Artery in older subjects. In both the brachial and the superficial Femoral Artery, no change in endothelial function in response to increased retrograde shear was observed in older males (‘time’ P=0.274, ‘cuff*time P=0.791’, ‘cuff*Artery*time P=0.774’). Conclusion In contrast with young subjects, we found that acute elevation in retrograde shear rate does not impair endothelial function in older humans. This may suggest that subjects with a priori endothelial dysfunction are less responsive or requires a larger shear rate stimulus to alter endothelial function.
-
acute impact of retrograde shear rate on brachial and superficial Femoral Artery Flow mediated dilation in humans
Physiological Reports, 2014Co-Authors: Tim H A Schreuder, Daniel J Green, Maria T E Hopman, Dick H J ThijssenAbstract:Retrograde shear rate (SR) in the brachial Artery (BA) is associated with endothelial dysfunction; a precursor to atherosclerosis. The BA does not typically manifest clinical atherosclerosis, whereas the superficial Femoral Artery (SFA) is more prone to developing plaque. Examine whether the impact of incremental levels of retrograde SR differs between atherosclerosis-prone (i.e., SFA) and -resistant vessels (i.e., BA) in healthy men. Thirteen healthy young men reported three times to the laboratory. We examined BA Flow-mediated dilation (FMD) before and after 30-min exposure to cuff inflation around the forearm at 0, 30, and 60 mmHg, to manipulate retrograde SR. Subsequently, the 30-min intervention was repeated in the SFA, using the same cuff pressure as in the forearm. Order of testing (vessel and intervention) was randomized among subjects. We found a dose-dependent increase in retrograde SR with 30 and 60 mmHg cuff inflation, which was present in both the BA and SFA (all P < 0.05). BA and SFA FMD decreased after the 30-min intervention (“time”: P = 0.012), and this was dependent on cuff pressure (“cuff 9 time”: P = 0.024). A significant decrease in FMD was observed after 60 mmHg only and this change was similarly present in both arteries (“time 9 Artery”: P = 0.227). Moreover, the BA and SFA demonstrate a similar relationship between changes in retrograde SR and FMD (r = 0.498 and 0.475, respectively). Our study demonstrates that acute exposure to an increase in retrograde shear leads to comparable decreases in FMD in atherosclerotic-prone and -resistant conduit arteries in humans.
Richard F M Wood - One of the best experts on this subject based on the ideXlab platform.
-
time averaged mean velocity for volumetric blood Flow measurements an in vitro model validation study using physiological Femoral Artery Flow waveforms
Ultrasound in Medicine and Biology, 1999Co-Authors: Richard D Walker, Roy Smith, Susan B Sherriff, Richard F M WoodAbstract:This study assesses the accuracy of the volume Flow measurement of the ATL HDI 3000 duplex ultrasound scanner using a model of the Femoral arterial circulation. The beam profile of the transducer was measured, and used to identify regions of the beam where there may be poor insonation characteristics. The Flow measurement accuracy was not found to be influenced by the vessel depth between 1.0 cm and 8.0 cm in a 0.7 cm diameter vessel. Overall accuracy was 3% ± 9%. Vessels in excess of 0.9 cm produced larger errors. In the model system, pulse rates between 60 bpm and 120 bpm had no significant effect on the measurement accuracy (p > 0.01). The results of this study suggest that accurate measurements of Femoral arterial blood Flow are possible. Further work will be required to assess the accuracy of the technique in vivo.
