Tu1407 Catheter Angulation and Pressure Are Major Determinants of Pressure Drift in Manoscan Esophageal High Resolution Manometry System

Cartoon of absorption of apoAV showing normal uptake via CEV, blockage of uptake by lyso-PC, and delivery of apoAV to the ER on CEV Tu1406 Effect of Induced Ischemia on Intestinal Fluid Secretion: A Novel Approach Abedalrazaq Alkukhun, Sami S. Judeeba, Armando Salim Munoz-Abraham, Roger PatronLozano, Manuel I. Rodriguez-Davalos, John P. Geibel Introduction: Intestinal ischemia can be seen in conditions such as mesenteric ischemia, or in a challenging situation like intestinal transplantation. Intestinal ischemia leads to physiological disruption that presents as increased fluid secretion into the lumen of the intestine. Limited research has been conducted to replicate these events ex-vivo. As part of a series of experiments that study fluid shift changes in the intestine, we present data on a new system from our lab that employs a (FITC) tagged inulin to measure fluid movement in semi real time. To reproduce ischemia in an animal model, we exposed a segment of the intestine to a hypoxic environment using Nitrogen gas bubbled perfusate, and compared it to a normoxic model taken from the same animal. We measured the fluid changes inside the lumen with a solution containing FITC-inulin. The purpose of this experiment was to understand the fluid alteration that occurs with intestinal ischemia, and determine if this assay is sensitive to measure the changes in fluid movement across the intact intestinal epithelia. Methods: Intestine was procured from male black-swiss mice. Two 10 cm segments were used: a control and an experimental. The control and experimental segments were filled with 1ml of HEPES solution containing 50μM of FITC-Inulin, and then were tied from both ends. The segments were mounted in beakers, filled with HEPES solution, placed in an H2O bath at 37° C. The control solution was left open to room air. The experimental solution was bubbled for 20 minutes with 100% N2 gas. The experimental beaker was sealed in order to prevent any N2 gas leak and to maintain the severe hypoxic environment. After 30 minutes, the segments were extracted from the beakers and fluid samples were taken from the lumen. The samples' intensity was taken in triplicate to measure the FITC-Inulin concentration. The length and diamter of the intestine was recorded for each segment. Results: When comparing the FITC-Inulin concentration in the experimental intestinal segments to the time zero starting measurements, we noted a reduction in the concentration of the fluorochrome indicative of a large secretion of fluid when compared to the starting value. When we examined and compared the ischemic tissue to the control tissue, we saw an approximate doubling of the amount of secretion over the same time period. This study demonstrates that FITC-Inulin can be used as a quantitative pathophysiological assay of ischemic injury in intact intestinal tissues. Conclusions: The FITC-Inulin can be used as a volume marker that equates to the ischemic state of the intestinal tissue. Furthermore, we propose that this model can be used for determining the viability of intestine that is being harvested and preserved in cold non oxygenated buffer solutions in preparation for transportation and holding prior to transplantation.

Tu1408 EGJ Relaxation During Sitting MRS Is Extreme in Normal Subjects but Feeble in Achalasia Patients Gardenia Carmo, Ricardo B. de Oliveira, Gustavo A. Mota Background and aim: Some studies show that EGJ relaxation, as evaluated by Integrated Relaxation Pressure (IRP), is more complete after single swallows (SS) performed in the upright than after supine position. In the supine position, multiple rapid swallowing (MRS) provokes a relaxation of the EGJ more intense than SS. We hypothesized that performing MRS in the sitting position would maximize EGJ relaxation and aimed to test the hypothesis in normal subjects and patients with achalasia. Methods: HRM studies including SS and MRS in both a supine and sitting position were done on 30 healthy volunteers (17 women, age: 20-55 years) and 31 patients with idiopathic achalasia (17 women, ages ranging from 22-76 years) by conventional criteria employing the Sandhill's HRM system (Insight HRiM®). Ten single-swallows of 5-cc saline and two MRS in each position were recorded. Data were analyzed by a single investigator (GCC) employing the BioViEw® analysis software. IRP were measured during supine SS, sitting SS, supine MRS, and sitting MRS. Results: IRP data are summarized in the table. In healthy volunteers, IRP during supine single swallows was significantly higher (p<0.01) than during sitting single swallows, sitting MRS, and supine MRS; IRP during sitting MRS was significantly lower (p<0.01) than during supine SS, sitting SS, and supine MRS; IRPs during supine MRS and sitting SS were not different (p> 0.05). IRP values of achalasia patients were virtually identical for all types of swallowing studied, and always significantly higher (p<0.01) than those measured in healthy volunteers. Conclusions: In normal subjects, based on IRP standard measure, EGJ relaxations after supine SS are less complete than after sitting SS, supine MRS, and sitting MRS. Siting MRS provokes an almost complete EGJ relaxation, nearly nullifying IRP in many subjects. In patients with idiopathic achalasia, EGJ relaxation is feeble in respect of type swallow. Integrated relaxation pressure (mmHg)

Tu1407 Catheter Angulation and Pressure Are Major Determinants of Pressure Drift in Manoscan Esophageal High Resolution Manometry System Arash Babaei, Steven D. Yorio, Mark Kern, Benson T. Massey, Reza Shaker Background: The accuracy of pressure measurements by Manoscan™ esophageal highresolution manometry (HRM) system is limited by development of a pressure drift (PD) throughout recording. The PD is affected by temperature and duration of pressure recording but other factors that contribute to PD have not been systematically evaluated. Aim: to comprehensively determine potential contributing factors to PD such as: duration of pressure recording; temperature, moisture and acidity of environment, catheter angulation, along with pressure application to sensors. Methods: Seven distinct esophageal HRM catheters were studied. To determine effect of circumferential pressure application HRM catheters were placed in a sealed pressure chamber connected to a barostat when 0-50 mmHg of pressure was applied for 10 minutes. To determine effect of catheter angulation a protractor was affixed to a flat surface and two pressure sensors were placed in 0, 15, 30, 45 and 60degree angles for 3 minutes. To determine effect of acidity and moisture HRM catheters were placed in a chamber filled with saline or 0.1 normal hydrochloric acid for 10 and 30 minutes with and without pressurization. To determine effect of temperature the HRM

IQR: Interquartile range; SS: single swallows; MRS: Multiple rapid swallows. Tu1409 Incomplete LES Relaxation Might Be the Primary and Maybe the Only Disturbance in Some Patients With Achalasia Hiroko Hosaka, Shiko Kuribayashi, Akiyo Kawada, Junichi Akiyama, Yasuyuki Shimoyama, Osamu Kawamura, Masanobu Yamada, Motoyasu Kusano Background and Aim: Both a failure of the lower esophageal sphincter (LES) to relax upon swallowing and absent peristalsis of the esophageal body have been essential manometric findings for establishing a diagnosis of esophageal achalasia. However, in clinical situations, some patients restored primary peristalsis just after a pneumatic dilatation which improved

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AGA Abstracts

AGA Abstracts

catheters were immersed in a water bath at 00, 220, 370, and 500celsius degrees for 10-30 minutes without pressure. The mean PD across all 36 sensors (overall PD) and the sensor with the highest amplitude of PD (peak PD) for each study were measured and presented as mean ± SD. Statistical analyses were made using analysis of variance with repeated measures and Tukey multiple comparisons. Results: As expected increasing temperature significantly increased PD that could reach 13 + 5 at 370Celsius degrees. There was significant difference across catheters and sensors in propensity to develop PD. At room temperature and without application of pressure, PD was negligible (<5 mmHg) irrespective of presence of saline and acid. Application of 50 mmHg pressure significantly increased PD in air, saline or acid environment compared to atmospheric pressure (p<0.0001). Saline and acid presence did not significantly affect PD with or without pressurization over time. Increased duration of recording during 50 mmHg of pressurization, and application of pressure for 10 minutes significantly increased PD up to 8 + 3 mmHg (p=0.02). Angulation of 30 degrees (or higher) increased PD up to 29 + 25 mmHg (p<0.0001). Conclusions: In addition to the known factors of temperature, sustained pressure and catheter angulation significantly contribute to development of PD which more likely to affect UES and LES measurements. Even slight angulation of catheter during manometry may affect pressure measurement accuracy. These findings need to be taken into account for interpretation of HRM results.

apoAV but did contain CEL. Rat intestinal fluid harvested post corn oil plus albumin gavage contained intact apoAV but greatly degraded albumin. We progressively increased the amount of phosphatidylcholine (PC) delivered to rat intestine using 5 different models. The amount of apoAV in intestinal cytosol was inversely related to the amount of PC delivered. Incubation of apoAV containing CEV with ER showed a 4 fold increase in ER-apoAV suggesting delivery of apoAV from CEV to the ER. Conclusions: We conclude that apoAV, unlike albumin, resists proteolysis in the intestinal tract. ApoAV is bound to caveolin-1 and CD36 on intestinal BB and is endocytosed via CEV. The CEV transport apoAV to the ER. ApoAV's binding to BB is controlled by PC concentrations in the intestinal lumen. CEL binds to clathrin and IAP and is endocytosed via clathrin coated vesicles, separate from the CEV pathway.