scholarly journals Gastrointestinal transit and prolonged ambulatory colonic motility in health and faecal incontinence

Gut ◽  
1997 ◽  
Vol 41 (3) ◽  
pp. 381-389 ◽  
Author(s):  
F Herbst ◽  
M A Kamm ◽  
G P Morris ◽  
K Britton ◽  
J Woloszko ◽  
...  
Keyword(s):  
High Pressure ◽  
Anal Sphincter ◽  
Faecal Incontinence ◽  
Urge Incontinence ◽  
Colonic Motility ◽  
Rhythmic Activity ◽  
High Amplitude ◽  
Left Colon ◽  
Pressure Waves ◽  
Colonic Motor

Background—Colonic motor function has not been studied in the ambulatory setting over a prolonged period in the unprepared state. Furthermore, the disturbance of this function in patients with faecal incontinence is unknown.Aim—To study colonic function over two to three days in the ambulatory, unprepared state in health and in patients with idiopathic faecal incontinence.Methods—Six healthy women and six women with faecal incontinence and a structurally intact anal sphincter ingested a dual radioisotope meal, and had a six sensor, solid state manometric probe colonoscopically inserted into the left colon. Scanning was performed until radioisotope left the gut and pressure was recorded for a median of 44 hours.Results—Three of six patients showed abnormal gastric emptying. Patients showed no disturbance of colonic radioisotope transit. Controls had a median of 12, whereas patients had a median of 16, high amplitude propagated waves per 24 hours. In three patients urge incontinence was associated with high amplitude (up to 500 cm water) propagated waves which often reached the rectum. These high pressure waves were identical to those occuring in healthy subjects, the only difference being the lack of adequate sphincter response. Passive incontinence was not associated with colonic motor activity. Defaecation in all subjects was associated with identical propagated waves, and distal movement of 13% (median) of right colonic content and excretion of 32% from the left colon and rectum. The urge to defaecate was associated with either propagated waves (45%) or non-propagated contractions (55%). Rectal motor complexes were recorded in both groups of subjects, but similar rhythmic activity was also recorded in the sigmoid and descending colon.Conclusions—Normal colonic function consists of frequent high pressure propagated waves. Rhythmic activity occurs both proximal to and in the rectum. Defaecation is characterised by high pressure propagated waves associated with coordinated anal sphincter relaxation. Patients with faecal incontinence may have a widespread disturbance of gut function. Urge incontinence, an urge to defaecate, and defaecation can all be associated with identical high amplitude propagated pressure waves.

scholarly journals On the nature of high-amplitude propagating pressure waves in the human colon

2020 ◽  
Vol 318 (4) ◽  
pp. G646-G660 ◽  
Author(s):  
Natalija Milkova ◽  
Sean P. Parsons ◽  
Elyanne Ratcliffe ◽  
Jan D. Huizinga ◽  
Ji-Hong Chen
Keyword(s):  
Healthy Subjects ◽  
Motor Pattern ◽  
High Amplitude ◽  
Proximal Colon ◽  
Pressure Waves ◽  
Sphincter Pressure ◽  
Average Amplitude ◽  
Colonic Motor ◽  
Balloon Distention ◽  
Descending Colon

Characterization of high-amplitude propagating pressure waves (HAPWs or HAPCs) plays a key role in diagnosis of colon dysmotility using any type of colonic manometry. With the introduction of high-resolution manometry, more insight is gained into this most prominent propulsive motor pattern. Here, we use a water-perfused catheter with 84 sensors with intervals between measuring points of 1 cm throughout the colon, for 6–8 h, in 19 healthy subjects. The catheter contained a balloon to evoke distention. We explored as stimuli a meal, balloon distention, oral prucalopride, and bisacodyl injection, with a goal to optimally evoke HAPWs. We developed a quantitative measure of HAPW activity, the “HAPW Index.” Our protocol elicited 290 HAPWs. 21% of HAPWs were confined to the proximal colon with an average amplitude of 75.3 ± 3.3 mmHg and an average HAPW Index of 440 ± 58 mmHg·m·s. 29% of HAPWs started in the proximal colon and ended in the transverse or descending colon, with an average amplitude of 87.9 ± 3.1 mmHg and an average HAPW Index of 3,344 ± 356 mmHg·m·s. Forty-nine percent of HAPWs started and ended in the transverse or descending colon with an average amplitude of 109.3 ± 3.3 mmHg and an average HAPW Index of 2,071 ± 195 mmHg·m·s. HAPWs with and without simultaneous pressure waves (SPWs) initiated the colo-anal reflex, often abolishing 100% of anal sphincter pressure. Rectal bisacodyl and proximal balloon distention were the most optimal stimuli to evoke HAPWs. These measures now allow for a confident diagnosis of abnormal motility in patients with colonic motor dysfunction. NEW & NOTEWORTHY High-amplitude propagating pressure waves (HAPWs) were characterized using 84 sensors throughout the entire colon in healthy subjects, taking note of site of origin, site of termination, amplitude, and velocity, and to identify optimal stimuli to evoke HAPWs. Three categories of HAPWs were identified, including the associated colo-anal reflex. Proximal balloon distention and rectal bisacodyl were recognized as reliable stimuli for evoking HAPWs, and a HAPW Index was devised to quantify this essential colonic motor pattern.

scholarly journals Cholinergic giant migrating contractions in conscious mouse colon assessed by using a novel noninvasive solid-state manometry method: modulation by stressors

2009 ◽  
Vol 296 (5) ◽  
pp. G992-G1002 ◽  
Author(s):  
G. Gourcerol ◽  
L. Wang ◽  
D. W. Adelson ◽  
M. Larauche ◽  
Y. Taché ◽  
...  
Keyword(s):  
High Frequency ◽  
Colonic Motility ◽  
Distal Colon ◽  
High Amplitude ◽  
Corticotrophin Releasing Factor ◽  
Colonic Manometry ◽  
Colonic Motor ◽  
Chronic Stressors ◽  
Giant Migrating Contractions

There is a glaring lack of knowledge on mouse colonic motility in vivo, primarily due to unavailability of adequate recording methods. Using a noninvasive miniature catheter pressure transducer inserted into the distal colon, we assessed changes in colonic motility in conscious mice induced by various acute or chronic stressors and determined the neurotransmitters mediating these changes. Mice exposed to restraint stress (RS) for 60 min displayed distal colonic phasic contractions including high-amplitude giant migrating contractions (GMCs), which had peak amplitudes >25 mmHg and occurred at a rate of 15–25 h−1 of which over 50% were aborally propagative. Responses during the first 20-min of RS were characterized by high-frequency and high-amplitude contractions that were correlated with defecation. RS-induced GMCs and fecal pellet output were blocked by atropine (0.5 mg/kg ip) or the corticotrophin releasing factor (CRF) receptor antagonist astressin-B (100 μg/kg ip). RS activated colonic myenteric neurons as shown by Fos immunoreactivity. In mice previously exposed to repeated RS (60 min/day, 14 days), or in transgenic mice that overexpress CRF, the duration of stimulation of phasic colonic contractions was significantly shorter (10 vs. 20 min). In contrast to RS, abdominal surgery abolished colonic contractions including GMCs. These findings provide the first evidence for the presence of frequent cholinergic-dependent GMCs in the distal colon of conscious mice and their modulation by acute and chronic stressors. Noninvasive colonic manometry opens new venues to investigate colonic motor function in genetically modified mice relevant to diseases that involve colonic motility alterations.

Characterization of haustral activity in the human colon

2021 ◽  
Author(s):  
Jan D. Huizinga ◽  
Maham Pervez ◽  
Sharjana Nirmathalasan ◽  
Ji-Hong Chen
Keyword(s):  
Motor Pattern ◽  
Colonic Motility ◽  
Human Colon ◽  
High Amplitude ◽  
Dominant Frequency ◽  
Pacemaker Activity ◽  
Pressure Waves ◽  
Baseline Pressure ◽  
Segmentation Pattern ◽  
Mixed Pattern

The human colon consists of a string of haustral compartments; hence all colonic motility involves haustra, yet contraction patterns are rarely discussed from the perspective of haustra. Haustral activity was analyzed in 21 healthy subjects using an 84-sensor manometry catheter with 1 cm spacing; haustra were on average 4.6 cm long, hence their activity was monitored by 4-5 sensors. On average 47% of the haustra were intermittently active for ~ 30% of the time; 2402 periods of haustra activity were analyzed. Intrahaustral activity showed rhythmic pressure waves centred around a frequency of 2-6 cpm or 7-15 cpm, or a checkerboard segmentation pattern. Boundaries of the haustra showed rhythmic pressure activity at a dominant frequency pf 3 cpm with or without elevated baseline pressure. The haustral activity was a low-amplitude motor pattern, 5-30 mmHg above baseline pressure. The intrahaustral rhythmic pressure waves propagated in a mixed pattern: retrograde, antegrade and simultaneous, with the simultaneous appearance dominating. Active haustra often showed no boundary activity probably allowing transit to neighbouring haustra. Haustral boundaries are seen at the same sensor for the 6-8 hr study duration, indicating that they do not propagate. Based on previous studies we infer that the orchestration of haustral activity involves pacemaker activity from ICC-SMP. High amplitude propagating pressure waves (HAPWs), were often followed by a cyclic motor pattern at a frequency ~ 12 cpm dissolving into haustral activity at that frequency. The HAPW may be composed of neurally-induced summated pressure waves at ~ 12 cpm.

scholarly journals Does chronic supplementation of the diet with dietary fibre extracted from pea or carrot affect colonic motility in man?

1996 ◽  
Vol 76 (1) ◽  
pp. 51-61 ◽  
Author(s):  
Claire GuéDon ◽  
Philippe Ducrotté ◽  
Jean Michel Antoine ◽  
Philippe Denis ◽  
Raymond Colin ◽  
...  
Keyword(s):  
Healthy Volunteers ◽  
Dietary Fibre ◽  
Colonic Motility ◽  
Fine Powder ◽  
High Amplitude ◽  
Initiation Site ◽  
Colonic Motor ◽  
Habitual Diet ◽  
Motor Effects ◽  
Usual Diet

The aim of the present study was to assess, in healthy volunteers and under physiological conditions, the acceptability, clinical tolerance and effects on colonic motility of chronic supplementation of the usual diet with new dietary fibre sources. Three studies were carried out, one after a period of habitual diet, and two after randomized 3-week periods of supplementation with fibre extracted either from pea hulls or carrots, added to the meals as a fine powder. The 24 h motility was recorded on an unprepared colon at five levels to determine the initiation site and the number of high amplitude propagated contractions (HAPC) and to quantify motor activity every 30 min, particularly in the two periods following lunch and breakfast. With the habitual diet the motility pattern was an irregular alternation of quiescence and sporadic non-propagated contractions. HAPC always started from the ascending colon and occurred mainly after breakfast. With either type of fibre the 24 h motor profiles, the 24 h variations and the number of HAPC were not significantly modified but a more distal initiation of HAPC was found. The colonic postprandial motor response was more diffuse after dietary enrichment with carrot fibre than after enrichment with pea-hull fibre. In healthy volunteers the long-term addition of fibre extracted from pea hulls and carrots to the usual diet was easy and well-tolerated without clinical side-effects, but with limited colonic motor effects. However, the more distal initiation of HAPC observed could be deleterious.

scholarly journals Peripheral peptide YY inhibits propulsive colonic motor function through Y2 receptor in conscious mice

2010 ◽  
Vol 298 (1) ◽  
pp. G45-G56 ◽  
Author(s):  
Lixin Wang ◽  
Guillaume Gourcerol ◽  
Pu-Qing Yuan ◽  
S. Vincent Wu ◽  
Mulugeta Million ◽  
...  
Keyword(s):  
Motor Function ◽  
Peptide Yy ◽  
Colonic Motility ◽  
Distal Colon ◽  
High Amplitude ◽  
Colonic Transit ◽  
Intraluminal Pressure ◽  
Antisecretory Effect ◽  
Nocturnal Feeding ◽  
Colonic Motor

Peptide YY (PYY) antisecretory effect on intestinal epithelia is well established, whereas less is known about its actions to influence colonic motility in conscious animals. We characterized changes in basal function and stimulated colonic motor function induced by PYY-related peptides in conscious mice. PYY3–36, PYY, and neuropeptide Y (NPY) (8 nmol/kg) injected intraperitoneally inhibited fecal pellet output (FPO) per hour during novel environment stress by 90%, 63%, and 57%, respectively, whereas the Y1-preferring agonists, [Pro34]PYY and [Leu31,Pro34]NPY, had no effect. Corticotrophin-releasing factor 2 receptor antagonist did not alter PYY3–36 inhibitory action. PYY and PYY3–36 significantly reduced restraint-stimulated defecation, and PYY3–36 inhibited high-amplitude distal colonic contractions in restrained conscious mice for 1 h, by intraluminal pressure with the use of a microtransducer. PYY suppression of intraperitoneal 5-hydroxytryptophan induced FPO and diarrhea was blocked by the Y2 antagonist, BIIE0246, injected intraperitoneally and mimicked by PYY3–36, but not [Leu31,Pro34]NPY. PYY3–36 also inhibited bethanechol-stimulated FPO and diarrhea. PYY3–36 inhibited basal FPO during nocturnal feeding period and light phase in fasted/refed mice for 2–3 h, whereas the reduction of food intake lasted for only 1 h. PYY3–36 delayed gastric emptying after fasting-refeeding by 48% and distal colonic transit time by 104%, whereas [Leu31,Pro34]NPY had no effect. In the proximal and distal colon, higher Y2 mRNA expression was detected in the mucosa than in muscle layers, and Y2 immunoreactivity was located in nerve terminals around myenteric neurons. These data established that PYY/PYY3–36 potently inhibits basal and stress/serotonin/cholinergic-stimulated propulsive colonic motor function in conscious mice, likely via Y2 receptors.

scholarly journals Ultrastructural changes in internal anal sphincter in neurogenic faecal incontinence.

Gut ◽  
1988 ◽  
Vol 29 (12) ◽  
pp. 1692-1698 ◽  
Author(s):  
M Swash ◽  
A Gray ◽  
D Z Lubowski ◽  
R J Nicholls
Keyword(s):  
Anal Sphincter ◽  
Faecal Incontinence ◽  
Internal Anal Sphincter ◽  
Ultrastructural Changes

5-Hydroxytryptophan activates colonic myenteric neurons and propulsive motor function through 5-HT4 receptors in conscious mice

2007 ◽  
Vol 292 (1) ◽  
pp. G419-G428 ◽  
Author(s):  
L. Wang ◽  
V. Martínez ◽  
H. Kimura ◽  
Y. Taché
Keyword(s):  
Motor Function ◽  
Colonic Motility ◽  
Distal Colon ◽  
Nadph Diaphorase ◽  
Maximal Response ◽  
Myenteric Neurons ◽  
Diaphorase Activity ◽  
Colonic Motor ◽  
Different Populations ◽  
Fos Expression

Serotonin [5-hydroxytryptamine (5-HT)] acts as a modulator of colonic motility and secretion. We characterized the action of the 5-HT precursor 5-hydroxytryptophan (5-HTP) on colonic myenteric neurons and propulsive motor activity in conscious mice. Fos immunoreactivity (IR), used as a marker of neuronal activation, was monitored in longitudinal muscle/myenteric plexus whole mount preparations of the distal colon 90 min after an intraperitoneal injection of 5-HTP. Double staining of Fos IR with peripheral choline acetyltransferase (pChAT) IR or NADPH-diaphorase activity was performed. The injection of 5-HTP (0.5, 1, 5, or 10 mg/kg ip) increased fecal pellet output and fluid content in a dose-related manner, with a peak response observed within the first 15 min postinjection. 5-HTP (0.5–10 mg/kg) dose dependently increased Fos expression in myenteric neurons, with a maximal response of 9.9 ± 1.0 cells/ganglion [ P < 0.05 vs. vehicle-treated mice (2.3 ± 0.6 cells/ganglion)]. There was a positive correlation between Fos expression and fecal output. Of Fos-positive ganglionic cells, 40 ± 4% were also pChAT positive and 21 ± 5% were NADPH-diaphorase positive in response to 5-HTP, respectively. 5-HTP-induced defecation and Fos expression were completely prevented by pretreatment with the selective 5-HT4 antagonist RS-39604. These results show that 5-HTP injected peripherally increases Fos expression in different populations of cholinergic and nitrergic myenteric neurons in the distal colon and stimulates propulsive colonic motor function through 5-HT4 receptors in conscious mice. These findings suggest an important role of activation of colonic myenteric neurons in the 5-HT4 receptor-mediated colonic propulsive motor response.

Large-Eddy Simulation of an Integrated High-Pressure Compressor and Combustion Chamber of a Typical Turbine Engine Architecture

2020 ◽  
Author(s):  
Carlos Pérez Arroyo ◽  
Jérôme Dombard ◽  
Florent Duchaine ◽  
Laurent Gicquel ◽  
Nicolas Odier ◽  
...  
Keyword(s):  
High Pressure ◽  
Large Eddy Simulation ◽  
Combustion Chamber ◽  
High Amplitude ◽  
Turbine Engine ◽  
Eddy Simulation ◽  
High Pressure Compressor ◽  
Large Eddy ◽  
Pressure Perturbations ◽  
Pressure Compressor

Abstract The design optimization of aviation propulsion systems by means of computational fluid dynamics is key to increase their efficiency and reduce pollutant and noise emissions. The recurrent increase in available computing power allows nowadays to perform unsteady high-fidelity computations of the different components of a gas turbine. However, these simulations are often made independently of each other and they only share average quantities at interfaces. In this work, the methodology and first results for a sectoral large-eddy simulation of an integrated high-pressure compressor and combustion chamber of a typical turbine engine architecture is proposed. In the simulation, the compressor is composed of one main blade and one splitter blade, two radial diffuser vanes and six axial diffuser vanes. The combustion chamber is composed of the contouring casing, the flame-tube and a T-shaped vaporizer. This integrated computation considers a good trade-off between accuracy of the simulation and affordable CPU cost. Results are compared between the stand-alone combustion chamber simulation and the integrated one in terms of global, integral and average quantities. It is shown that pressure perturbations generated by the interaction of the impeller blades with the diffuser vanes are propagated through the axial diffuser and enter the combustion chamber through the dilution holes and the vaporizer. Due to the high amplitude of the pressure perturbations, several variables are perturbed at the blade-passing frequency and multiples. This is also reflected on combustion where two broadband peaks appear for the global heat release.

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