Showing papers by "Wenguang Li published in 2011"
TL;DR: The model was applied to 51 subjects and the peak total stress was found to have a strong correlation with the pain stimulated by CCK, as measured by the patient pain score questionnaires, and the success rate in predicting of CCK-induced pain is over 75%.
Abstract: This study investigates the potential correlation between acalculous biliary pain and mechanical stress during the bile-emptying phase. This study is built on the previously developed mathematical model used to estimate stress in the gallbladder wall during emptying [Li, W. G., X. Y. Luo, et al. Comput. Math. Methods Med. 9(1):27-45, 2008]. Although the total stress was correctly predicted using the previous model, the contribution from patient-specific active stress induced by the cholecystokinin (CCK) test was overlooked. In this article, we evaluate both the active and passive components of pressure in a gallbladder, which undergoes isotonic refilling, isometric contraction and emptying during the infusion of CCK. The pressure is estimated from in vivo ultrasonographical scan measurements of gallbladder emptying during CCK tests, assuming that the gallbladder is a thin ellipsoidal membrane. The passive stress is caused by the volume and shape changes during refilling at the gallbladder basal pressure, whereas the active stress arises from the pressure rise during the isometric gallbladder contraction after the CCK infusion. The effect on the stress estimates of the gallbladder to the liver is evaluated to be small by comparing numerical simulations of a gallbladder model with and without a rigid 'flat top' boundary. The model was applied to 51 subjects, and the peak total stress was found to have a strong correlation with the pain stimulated by CCK, as measured by the patient pain score questionnaires. Consistent with our previous study for a smaller sample, it is found that the success rate in predicting of CCK-induced pain is over 75%.
16 citations
TL;DR: The study suggests that the apparent rate constants should be patient-specific, i.e. patients with a lower stress level are characterized by smaller apparent rate constant, and the diseased GB may need to develop fast cycling cross-bridges to compensate in the emptying process.
Abstract: This paper studies human gallbladder (GB) smooth muscle contractions. A two-state cross-bridge model was used to estimate the apparent attachment and detachment rate constants, as well as increased Ca2+ concentration from the peak active stress during the isometric contraction. The active stress was computed from a mechanical model based entirely on non-invasive routine ultrasound scans. In the two-state cross-bridge model, the two apparent rate constants, representing the total attached/detached cross-bridges, respectively, were estimated using active stress prediction for 51 subjects undergoing cholecystokinin-provocation test, together with estimates from the four-state cross-bridge model for a swine carotid, bovine tracheal and guinea pig GB smooth muscles. The study suggests that the apparent rate constants should be patient-specific, i.e. patients with a lower stress level are characterized by smaller apparent rate constants. In other words, the diseased GB may need to develop fast cycling cross-bridges to compensate in the emptying process. This is a first step towards more quantitative and non-invasive measures of GB pain, and may provide useful insight in understanding GB motility and developing effective drug treatments.
5 citations