Volume 124, Issue 5, Pages 1230-1239 (May 2003) Pain and biomechanical responses to distention of the duodenum in patients with systemic sclerosis  Jan Pedersen, Chunwen Gao, Henrik Egekvist, Peter Bjerring, Lars Arendt-nielsen, Hans Gregersen, Asbjørn Mohr Drewes  Gastroenterology  Volume 124, Issue 5, Pages 1230-1239 (May 2003) DOI: 10.1016/S0016-5085(03)00265-8

Figure 1 Schematic of a smooth muscle strips length-tension diagram as obtained in organ bath studies in vitro. The total tension can be separated into active and passive components by pharmacologic testing. The active tension (smooth muscle component) is computed by subtraction of the passive tension (resulting from passive components such as the extracellular collagen and obtained from the test with butylscopolamine) from the total tension. Asterisk indicates the local maximum in active tension (Max TA). Vertical dotted line is the corresponding strain (optimum length). Gastroenterology 2003 124, 1230-1239DOI: (10.1016/S0016-5085(03)00265-8)

Figure 2 Example of manometric tracings obtained in the fed state before the distentions in a typical control subject (A) and patient (B). The average contraction frequency and amplitudes were decreased in the patients. Gastroenterology 2003 124, 1230-1239DOI: (10.1016/S0016-5085(03)00265-8)

Figure 3 Example of mechanical stimulation of the duodenum, in which the bag was filled with an infusion speed of 25 mL/min. During the distention the pressure, cross-sectional area (CSA), and pain intensity were recorded on-line. The pain intensity was rated on an electronic visual analogue scale (VAS), with 5 as the pain threshold. The pump was reversed at an intensity of 7 on the VAS, corresponding with moderate pain. Gastroenterology 2003 124, 1230-1239DOI: (10.1016/S0016-5085(03)00265-8)

Figure 4 The cross-sectional area (CSA), pressure, tension, and strain as function of the normalized volume. The volume was normalized with respect to the maximal volume at VAS = 7 in each subject and expressed as fractions of the maximal volume. Mean and SEM values are shown. The curves show healthy subjects without (■) and with (□) butylscopolamine to relax the smooth muscle and systemic sclerosis patients (stippled lines) without (•) and with (○) butylscopolamine. Gastroenterology 2003 124, 1230-1239DOI: (10.1016/S0016-5085(03)00265-8)

Figure 5 Length-tension diagrams as tension-normalized volume (A) and tension strain (B). Figure 4 legend explains how the normalized volume was computed. Mean and SEM values are shown in the top Figure, but, to facilitate the reading, SEM is not shown in the bottom Figure. The mean values for the total, passive, and active tensions are shown for patients (stippled lines) and controls (black lines). For further explanation, see Figure 1. Gastroenterology 2003 124, 1230-1239DOI: (10.1016/S0016-5085(03)00265-8)

Figure 6 The perception score (rated on an electronic visual analogue scale [VAS] with 5 as the pain threshold and 7 as moderate pain) as function of cross-sectional area (CSA), pressure, tension, and strain. Mean and SEM values are shown. The curves show healthy subjects without (■) and with (□) butylscopolamine administration to relax the smooth muscle and systemic sclerosis patients (stippled lines) without (•) and with (○) the drug. Gastroenterology 2003 124, 1230-1239DOI: (10.1016/S0016-5085(03)00265-8)