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| 1 | Gastrointestinal tract modelling in health and disease显示文摘The gastrointestinal (GI) tract is the system of organs within multi-cellular animals that takes in food, digests it to extract energy and nutrients, and expels the remaining waste. The various patterns of GI tract function are generated by the integrated behaviour of multiple tissues and cell types. A thorough study of the GI tract requires understanding of the interactions between cells, tissues and gastrointestinal organs in health and disease. This depends on knowledge, not only of numerous cellular ionic current mechanisms and signal transduction pathways, but also of large scale GI tissue structures and the special distribution of the nervous network. A unique way of coping with this explosion in complexity is mathematical and computational modelling; providing a computational framework for the multilevel modelling and simulation of the human gastrointestinal anatomy and physiology. The aim of this review is to describe the current status of biomechanical modelling work of the GI tract in humans and animals, which can be further used to integrate the physiological, anatomical and medical knowledge of the GI system. Such modelling will aid research and ensure that medical professionals benefit, through the provision of relevant and precise information about the patient's condition and GI remodelling in animal disease models. It will also improve the accuracy and efficiency of medical procedures, which could result in reduced cost for diagnosis and treatment. | Dong-Hua Liao Jing-Bo Zhao Hans Gregersen Hans Gregersen | 2009 | World Journal of Gastroenterology2009，15，2： | 3 |
| 2 | Axial force measurement for esophageal function testing显示文摘The esophagus serves to transport food and fluid from the pharynx to the stomach. Manometry has been the 'golden standard' for the diagnosis of esophageal motility diseases for many decades. Hence, esophageal function is normally evaluated by means of manometry even though it reflects the squeeze force (force in radial direction) whereas the bolus moves along the length of esophagus in a distal direction. Force measurements in the longitudinal (axial) direction provide a more direct measure of esophageal transport function. The technique used to record axial force has developed from external force transducers over in-vivo strain gauges of various sizes to electrical impedance based measurements. The amplitude and duration of the axial force has been shown to be as reliable as manometry. Normal, as well as abnormal, manometric recordings occur with normal bolus transit, which have been documented using imaging modalities such as radiography and scintigraphy. This inconsistency using manometry has also been documented by axial force recordings. This underlines the lack of information when diagnostics are based on manometry alone. Increasing the volume of a bag mounted on a probe with combined axial force and manometry recordings showed that axial force amplitude increased by 130% in contrast to an increase of 30% using manometry. Using axial force in combination with manometry provides a more complete picture of esophageal motility, and the current paper outlines the advantages of using this method. | Flemming H Gravesen Peter Funch-Jensen Hans Gregersen Asbjφrn Mohr Drewes | 2009 | World Journal of Gastroenterology2009，15，2： | 2 |
| 3 | Effect of local longitudinal shortening on the transport of luminal contents through small intestine显示文摘A theoretical analysis of the rheological fluid flow due to peristalsis is studied. We have applied the classical lubrication theory to predict the near physiological behavior of the intestinal segment, mixing and transport. A parametric study involving the changes in local longitudinal shortening (LLS) magnitude, LLS spacing, fluid viscosity, wavelength of the wave, and occlusion of lumen caused by the wave provided insights into the dynamics of the peristalsis flow of a non-Newtonian fluid. LLS appear to have little significance in modulating the flow patterns that are caused by circular contraction alone. Results also indicate that there exists trade-off between the power requirement for peristalsis at a certain occlusion against the percentage LLS. LLS appear to be more advantageous to perform the peristalsis activity at higher occlusion than lower occlusion. Having mucosal folds in the inner lining of the intestine allows for one more advantage of slowing the transit due to increased friction factor and increase in time for absorption of the nutrients. | Ravi Kant Avvari | 2019 | Acta Mechanica Sinica2019，35，1： | 1 |
| 4 | Lower esophageal sphincter relaxation is impaired in older patients with dysphagia显示文摘AIM: To characterize the effects of age on the mechanisms underlying the common condition of esophageal dysphagia in older patients, using detailed manometric analysis. METHODS: A retrospective case-control audit was performed on 19 patients aged ≥ 80 years (mean age 85 ± 0.7 year) who underwent a manometric study for dysphagia (2004-2009). Data were compared with 19 younger dysphagic patients (32 ± 1.7 years). Detailed manometric analysis performed prospectively included basal lower esophageal sphincter pressure (BLESP), pre-swallow and nadir LESP, esophageal body pressures and peristaltic duration, during water swallows (5 mL) in right lateral (RL) and upright (UR) postures and with solids. Data are mean ± SE; a P-value < 0.05 was considered significant. RESULTS: Elderly dysphagic patients had higher BLESP than younger patients (23.4 ± 3.8 vs 14.9 ± 1.2 mmHg; P < 0.05). Pre-swallow LESP was elevated in the elderly in both postures (RL: 1 and 4 s P = 0.019 and P = 0.05; UR: P < 0.05 and P = 0.05) and solids (P < 0.01). In older patients, LES nadir pressure was higher with liquids (RL: 2.3 ± 0.6 mmHg vs 0.7 ± 0.6 mmHg, P < 0.05; UR: 3.5 ± 0.9 mmHg vs 1.6 ± 0.5 mmHg, P = 0.01) with shorter relaxation after solids (7.9 ± 1.5 s vs 9.7 ± 0.4 s, P = 0.05). No age-related differences were seen in esophageal body pressures or peristalsis duration. CONCLUSION: Basal LES pressure is elevated and swallow-induced relaxation impaired in elderly dysphagic patients. Its contribution to dysphagia and the effects of healthy ageing require further investigation. | Laura K Besanko Carly M Burgstad Reme Mountifi eld Jane M Andrews Richard Heddle Helen Checklin Robert JL Fraser | 2011 | World Journal of Gastroenterology2011，17，10： | 0 |
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