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Do we really understand the role of the oesophagogastric junction in disease?

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World Journal of Gastroenterology 2009年第2期15卷 144-150页

作者： Barry P McMahon Blair A Jobe John E Pandolfino Hans gregersen Department of Medical Physics & Clinical Engineering Adelaide & Meath Hospital Tallaght Dublin 24 Ireland Associate Professor of Surgery Director of Esophageal Diagnostics & Therapeutic Endoscopy Heart Lung and Esophageal Surgery Institute University of Pittsburgh Medical Centre Shadyside Medical Building Suite 715 Pittsburgh PA 15232 United States Division of Gastroenterology Northwestern Memorial University Hospital 676 N. St. Clair St. Suite 1400 Chicago IL 60611 United States Professor of Biomechanics Director of Research Mech-Sense Aalborg Hospital Science and Innovation Centre Sφndre Skovvej 15 9000 Aalborg Denmark

The role of the oesophago-gastric junction (OGJ) in gastro-oesophageal reflux disease is still not completely understood, and there is no clinically used method to assess the OGJ function in patients. Only indirect methods such as pH studies are carried out. The OGJ acts a valve controlling the flow of solids, liquids and gases between the oesophagus and the stomach. Manometry can determine if a sphincter is toned or relaxed; but, it cannot confirm that the sphincter region is actually open. Distension is a new technique for measuring function in the OGJ. By measuring the cross-sectional area through the narrow region in the junction during distension of a catheter mounted bag, much more information on the opening and closing patterns of the junction can be determined. This technique has already been demonstrated to show changes in the OGJ after surgical treatments for reflux disease. New measurement ideas around the concept of distending the OGJ offer new hope that a clinically useable test for compliance at the junction can be developed and could potentially help in determining appropriate therapy.

关键词： Achalasia Distensibility Impedance Planimetry Intraluminal impedance manometry Oesophago-gastric junction

Where Psychology Meets Language Learning:Exploring the Positive Nexus

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Chinese Journal of Applied Linguistics 2022年第1期45卷 7-16,150页

作者： Tammy gregersen Department of English College of Arts and SciencesAmerican University of SharjahUAE

This paper provides an overview of positive psychology(PP),or the study of elements that make life most worth living(Peterson,2006),and demonstrates its efficacy by detailing five intervention *** aligning PP objectives and linguistic aims in second language teaching and learning,the studies show multiplied,concurrent results,heightened teacher and learner wellbeing and improved language *** important caveat is that PP interventions work best when they cater specifically to individual learners.

关键词： positive psychology wellbeing interventions emotions signature strengths savoring gratitude

Experimental human pain models in gastro-esophageal reflux disease and unexplained chest pain

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World Journal of Gastroenterology 2006年第18期12卷 2805-2817页

作者： Asbjφrn Mohr Drewes Lars Arendt-Nielsen Peter Funch-Jensen Hans gregersen Center for Visceral Biomechanics and Pain Department of GastroenterologyAalborg Hospitaland Center for Sensory-Motor InteractionsDepartment of Health Science and TechnologyAalborg UniversityDenmark Department of Surgical Gastroenterology L Aarhus HospitalDenmark

Methods related to experimental human pain research aim at activating different nociceptors, evoke pain from different organs and activate specific pathways and mechanisms. The different possibilities for using mechanical, electrical, thermal and chemical methods in visceral pain research are discussed with emphasis of combinations (e.g., the multimodal approach). The methods have been used widely in assessment of pain mechanisms in the esophagus and have contributed to our understanding of the symptoms reported in these patients. Hence abnormal activation and plastic changes of central pain pathways seem to play a major role in the symptoms in some patients with gastro-esophageal reflux disease and in patients with functional chest pain of esophageal origin. These findings may lead to an alternative approach for treatment in patients that does not respond to conventional medical or surgical therapy.

关键词： Pain Gut Experimental Chest pain Esophagitis

Time-dependent viscoelastic properties along rat small intestine

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World Journal of Gastroenterology 2005年第32期11卷 4974-4978页

作者： James B Smith Jing-Bo Zhao Yan-Ling Dou Hans gregersen Institute of Experimental Clinical Research Aarhus University Denmark Center of Excellence in Visceral Biomechanics and Pain Aalborg Hospital and Center of SMI Aalborg University Aalborg Denmark Department of Gastroenterology China-Japan Friendship Hospital Beijing 100029 China

AIM： To measure the time-dependent （viscoelastic） behavior in the change of the small intestinal opening angle and to test how well the behavior could be described by the Kelvin model for a standard linear solid. METHODS： Segments from the duodenum, jejunum, and ileum were harvested from 10 female Wistar rats and the luminal diameter, wall thickness, and opening angle over time （θ（t）） were measured from rings cut from these segments. RESULTS： Morphometric variations were found along the small intestine with an increase in luminal area and a decrease in wall thickness from the duodenum to the ileum. The opening angle obtained after 60 rain was highest in the duodenum （220.8±12.9°）and decreased along the length of the intestine to 143.9±8.9° in the jejunum and 151.4±9.4° in the ileum. The change of opening angle as a function of time, fitted well to the Kelvin model using the equation θ（t）/θo = [1-ηexp （-λt）] after the ring was cut. The computed creep rate λ. did not differ between the segments. Compared to constant calculated from pig aorta and coronary artery, it showed that α agreed well （within 5%）, η was three times larger than that for vascular tissue, and λ ranged ±40% from the value of the pig coronary artery and was a third of the value of pig aorta. CONCLUSION： The change of opening angle over time for all the small intestine segments fits well to the standard linear spring-dashpot model. This viscoelastic constant of the rat small intestine is fairly homogenous along its length. The data obtained from this study add to a base set of biomechanical data on the small intestine and provide a reference state for comparison to other tissues,diseased intestinal tissue or intestinal tissue exposed to drugs or chemicals.

关键词： Biomechanics Standard linear solid Creep Opening angle

Computation of flow through the oesophagogastric junction

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World Journal of Gastroenterology 2007年第9期13卷 1360-1364页

作者： Barry P McMahon Karl D Odie Kenneth W Moloney Hans gregersen Department of Medical Physics and Clinical Engineering Adelaide and Meath Hospital Dublin Incorporating the National Children’s Hospital Tallaght Dublin 24Ireland IMed Centre Department of Mechanical Engineering Institute of Technology Tallaght Dublin 24 Ireland Center for Visceral Biomechanics and Pain Aalborg Hospital Aalborg DK-9100 DenmarkIMed Centre Institute of Technology Tallaght Dublin 24 Ireland

Whilst methods exist to indirectly measure the effects of increased flow or gastro-oesophageal refluxing, they cannot quantitatively measure the amount of acid travelling back up into the oesophagus during reflux, nor can they indicate the flow rate through the oesophagogastric junction (OGJ). Since OGJ dysfunction affects flow it seems most appropriate to describe the geometry of the OGJ and its effect on the flow. A device known as the functional lumen imaging probe (FLIP) has been shown to reliably measure the geometry of and pressure changes in the OGJ. FLIP cannot directly measure flow but the data gathered from the probe can be used to model flow through the junction by using computational flow dynamics (CFD). CFD uses a set of equations known as the Navier-Stokes equations to predict flow patterns and is a technique widely used in engineering. These equations are complex and require appropriate assumptions to provide simplifications before useful data can be obtained. With the assumption that the cross-sectional areas obtained via FLIP are circular, the radii of these circles can be obtained. A cubic interpolation scheme can then be applied to give a high-resolution geometry for the OGJ. In the case of modelling a reflux scenario, it can be seen that at the narrowest section a jet of fluid squirts into the oesophagus at a higher velocity than the fluid surrounding it. This jet has a maximum velocity of almost 2 ms-1 that occurs where the OGJ is at its narrowest. This simple prediction of acid ‘squirting’ into the oesophagusillustrates how the use of numerical methods can be used to develop a better understanding of the OGJ. This initial work using CFD shows some considerable promise for the future.

关键词： Computational flow dynamics model Oesophagus

Imaging of the gastrointestinal tract-novel technologies

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World Journal of Gastroenterology 2009年第2期15卷 160-168页

作者： Jens Brφndum Frφkjr Asbjφrn Mohr Drewes Hans gregersen Mech-Sence Aalborg HospitalDK-9000 Aalborg Denmark Department of Radiology Aalborg Hospital DK-9000 Aalborg Denmark Mech-Sence Aalborg Hospital DK-9000 Aalborg Denmark Mech-Sense Department of Medical Gastroenterology Aalborg University Hospital DK-9000 Aalborg Denmark National Center for Ultrasound in Gastroenterology Haukeland University Hospital Bergen Norway Center for Sensory-Motor Interaction (SMI) Department of Health Science and Technology Aalborg University Denmark Center for Sensory-Motor Interaction (SMI) Department of Health Science and Technology Aalborg University DK-9000 Aalborg Denmark

Imaging of the gastrointestinal tract is very useful for research and clinical studies of patients with symptoms arising from the gastrointestinal tract and in visualising anatomy and pathology. Traditional radiological techniques played a leading role in such studies for a long time. However, advances in non-invasive modalities including ultrasound (US), computed tomography (CT), positron emission tomography (PET), magnetic resonance imaging (MRI), etc, have in the last decades revolutionised the way in which the gastrointestinal tract is studied. The resolution of imaging data is constantly being improved and 3D acquisition, tools for fi ltering, enhancement, segmentation and tissue classif ication are continually being developed. Additional co-registration techniques allow multimodal data acquisition with improved classif ication of tissue pathology. Furthermore, new functional imaging techniques have become available. Altogether, the future of gastrointestinal imaging looks very promising which will be of great benef it in clinical and research studies of gastrointestinal diseases. The purpose of this review is to highlight the capabilities of the newest techniques to explore the detailed morphology, biomechanical properties, function and pathology of the gastrointestinal tract.

关键词： Computed tomography Gastrointestinaltract Imaging Magnetic resonance Radiology Ultrasound

Axial force measurement for esophageal function testing

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World Journal of Gastroenterology 2009年第2期15卷 139-143页

作者： Flemming H Gravesen Peter Funch-Jensen Hans gregersen Asbjφrn Mohr Drewes Mech-Sense Department of Gastroenterology Aalborg Hospital Aalborg Denmark Center for Sensory-Motor Interaction (SMI) Department of Health Science and Technology Aalborg University DK-9000 Aalborg Denmark Department of Surgical Gastroenterology L rhus University Hospital rhus Denmark

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.

关键词： Axial force Traction force Manometry Motility Peristalsis Esophageal function

Ultrasonographic study of mechanosensory properties in human esophagus during mechanical distension

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World Journal of Gastroenterology 2006年第28期12卷 4517-4523页

作者： Ejnar Larsen Hariprasad Reddy AsbjΦrn Mohr Drewes Lars Arendt-Nielsen Hans gregersen Department of Radiology Aalborg HospitalAalborg DK-9100Denmark Center for Visceral Biomechanics and Pain Aalborg HospitalAalborg DK-9100Denmark Laboratory for Experimental Pain Research Center for Sensory-Motor InteractionDepartment of Health TechnologyAalborg UniversityAalborg Dk-9100Denmark

TIM： To study the esophageal geometry and mechanosensation using endoscopic ultrasonography during volume-controlled ramp distensions in the distal esophagus. METHODS： Twelve healthy volunteers underwent distension of a bag. During distension up to moderate pain the sensory intensity was assessed on a visual analogue scale （VAS）. The esophageal deformation in terms of multidimensional stretch ratios and strains was calculated at different volumes and VAS levels. Distensions were done before and during administration of the anticholinergic drug butylscopolamine. RESULTS： The stimulus-response （volume-VAS） curve did not differ without or with the administration of butylscopolamine. Analysis of stretch ratios demonstrated tensile stretch in circumferential direction, compression in radial direction and a small tensile stretch in longitudinal direction. A strain gradient existed throughout the esophageal wall with the largest circumferential deformation at the mucosal surface. The sensation intensity increased exponentially as function of the strains. CONCLUSION： The method provides information of esophageal deformation gradients that correlate to the sensation intensity. Hence, it can be used to study mechanosensation in the human esophagus. Further studies are needed to determine the exact deformation stimulus for the esophageal mechanoreceptors.

关键词： Deformation analysis Esophagus Experimental pain Ultrasonography

Morphology and motor function of the gastrointestinal tract examined with endosonography

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World Journal of Gastroenterology 2006年第18期12卷 2858-2863页

作者： Svein Odegaard Lars Birger Nesje Dag Arne Lihaug Hoff Odd Helge Gilja Hans gregersen National Centre for Ultrasound in Gastroenterology Department of MedicineHaukeland University HospitalBergenNorway Institute of MedicineUniversity of BergenBergenNorway Institute of Medicine University of BergenBergenNorway Department of MedicineAalesund HospitalAalesundNorway Institute of Medicine University of BergenBergenNorway Centre for Visceral Biomechanics and PainAalborg HospitalSMIAalborg UniversityAalborgDenmark

Endosonography is a useful tool for studying the morphology and motor function of the gastrointestinal tract. Intraluminal ultrasonography is the common denomination of ultrasound examinations using intracorporal transducers which are inserted into the GI tract. Thus, the visceral wall and adjacent structures can be imaged in detail. This review describes the usefulness of endosonography in gastroenterology, in particular with respect to studies of the biomechanical and motor function of the gastrointestinal tract. New techniques such as 3-D EUS, elastography and strain rate imaging are discussed.

关键词： Intraluminal ultrasonography Gastrointestinal tract Imaging Biomechancs