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Time-Dependent Alterations of Gut Wall Integrity in Small Bowel Obstruction in Mice. J Surg Res 2019; 233:249-255. [DOI: 10.1016/j.jss.2018.07.038] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Revised: 06/18/2018] [Accepted: 07/13/2018] [Indexed: 01/01/2023]
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Bertoni S, Saccani F, Gatti R, Rapalli A, Flammini L, Ballabeni V, Barocelli E. Accommodation and peristalsis are functional responses to obstruction in rat hypertrophic ileum. World J Gastroenterol 2013; 19:846-54. [PMID: 23430377 PMCID: PMC3574881 DOI: 10.3748/wjg.v19.i6.846] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/04/2012] [Revised: 09/13/2012] [Accepted: 09/22/2012] [Indexed: 02/06/2023] Open
Abstract
AIM: To investigate the effects of chronic obstruction on enteric reflexes evoked by electrical stimulation (EFS) or intraluminal distension of the rat hypertrophic ileum.
METHODS: Motor responses to EFS and to intraluminal distension were studied in the absence and in the presence of various inhibitors of enteric mediators. Ileum segments from operated (chronic ileal obstruction), sham-operated (control) and normal rats were horizontally mounted, connected to a pressure transducer and intraluminally perfused. The effects of selective serotonin receptor (5-HTR) blockers were investigated on distension-induced responses. The cellular localization of 5-HT3Rs was also examined in control and hypertrophic tissues through confocal microscopy.
RESULTS: In non-obstructed segments, EFS elicited tetrodotoxin (TTX)-sensitive responses with high amplitude contraction followed by weak relaxation. In hypertrophic tissues, EFS lowered the baseline pressure and evoked TTX-sensitive contractions significantly larger than normal (P < 0.01) or control (P < 0.05), and devoid of any relaxation phase (P < 0.01 vs normal). Incubation with atropine and guanethidine [non-adrenergic non-cholinergic (NANC) conditions] did not modify intestinal tone in normal and control preparations, but reversed the accommodation produced by EFS in hypertrophic tissues, and depressed the amplitude of contractions in all types of tissues. L-NAME and α-chymotrypsin blocked residual NANC motility in all tissues and augmented intraluminal pressure in hypertrophic segments (P < 0.05 vs NANC conditions). Intraluminal distension of the intestinal wall evoked non-propulsive cycles of contractions and relaxations in non-obstructed tissues. In all hypertrophic segments, strong propulsive strokes, markedly wider (P < 0.001), and larger than normal (P < 0.001) or control (P < 0.05) were elicited. Both motor patterns were blocked under NANC conditions and with simultaneous incubation with L-NAME and α-chymotrypsin. In all types of tissues, incubation with ketanserin or GR125487 did not modify distension-induced motility. In contrast, blockade of 5-HT3Rs by ondansetron concentration-dependently inhibited motor responses in normal and control tissues, but only slightly impaired enteric reflexes in the hypertrophic preparations. Finally, confocal microscopy did not reveal a different cellular distribution of 5-HT3Rs in control and hypertrophic ileum.
CONCLUSION: Accommodation and distension-induced peristalsis of rat hypertrophic ileum are controlled by cholinergic and peptidergic transmission and are negligibly affected by 5-HT3Rs, which modulate distension-induced motility in non-obstructed tissues.
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Zhao J, Liao D, Yang J, Gregersen H. Stress and strain analysis of contractions during ramp distension in partially obstructed guinea pig jejunal segments. J Biomech 2011; 44:2077-82. [PMID: 21632056 PMCID: PMC3150803 DOI: 10.1016/j.jbiomech.2011.05.017] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2010] [Revised: 04/15/2011] [Accepted: 05/11/2011] [Indexed: 12/21/2022]
Abstract
Previous studies have demonstrated morphological and biomechanical remodeling in the intestine proximal to an obstruction. The present study aimed to obtain stress and strain thresholds to initiate contraction and the maximal contraction stress and strain in partially obstructed guinea pig jejunal segments. Partial obstruction and sham operations were surgically created in mid-jejunum of male guinea pigs. The animals survived 2, 4, 7 and 14 days. Animals not being operated on served as normal controls. The segments were used for no-load state, zero-stress state and distension analyses. The segment was inflated to 10 cmH(2)O pressure in an organ bath containing 37°C Krebs solution and the outer diameter change was monitored. The stress and strain at the contraction threshold and at maximum contraction were computed from the diameter, pressure and the zero-stress state data. Young's modulus was determined at the contraction threshold. The muscle layer thickness in obstructed intestinal segments increased up to 300%. Compared with sham-obstructed and normal groups, the contraction stress threshold, the maximum contraction stress and the Young's modulus at the contraction threshold increased whereas the strain threshold and maximum contraction strain decreased after 7 days obstruction (P<0.05 and 0.01). In conclusion, in the partially obstructed intestinal segments, a larger distension force was needed to evoke contraction likely due to tissue remodeling. Higher contraction stresses were produced and the contraction deformation (strain) became smaller.
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Affiliation(s)
- Jingbo Zhao
- Institute of Clinical Medicine, Aarhus University, Aarhus, Denmark.
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Bertoni S, Ballabeni V, Flammini L, Gobbetti T, Impicciatore M, Barocelli E. Intestinal chronic obstruction affects motor responsiveness of rat hypertrophic longitudinal and circular muscles. Neurogastroenterol Motil 2008; 20:1234-42. [PMID: 18684211 DOI: 10.1111/j.1365-2982.2008.01174.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Extensive morphological and neurochemical changes have been experimentally and clinically documented in the hypertrophied intestine located orally to a chronic partial stenosis of the lumen. Functional studies revealed not only disruption of the interdigestive motor complex in vivo and decreased efficiency of contraction but also preservation of the peristaltic reflex in vitro. Given the critical role played in intestinal peristalsis by the coordinated activity of the longitudinal (LM) and circular muscle (CM), this work focuses on the motor responses of LM and CM isolated from rat hypertrophied ileum following mechanical obstruction. Maximal contractions to both receptor (acetylcholine and substance P) and non-receptor (K+) mediated stimuli were up to 10-fold increased in hypertrophic CM rings compared with control tissues, while a higher potency of substance P was revealed in both hypertrophied muscle layers. Relaxations to vasoactive intestinal polypeptide and 8-Br-cGMP were more intense on prostaglandin F(2alpha)-contracted hypertrophic LM strips compared with control tissues and a general tendency towards increased relaxation was shared also by hypertrophic CM basal tone. The present results collectively suggest that hypertrophic growth leads to hyperresponsiveness to contractile agents, particularly evident in the CM, and to increased sensitivity to relaxing mediators, especially exhibited by the LM. In this regard, the complementary role exerted by each muscle layer and the plasticity of the intestinal tissue could both come into play to preserve the intestinal functions in a changing environment.
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Affiliation(s)
- S Bertoni
- Department of Pharmacological, Biological and Applied Chemical Sciences, University of Parma, Parma, Italy
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Storkholm JH, Zhao J, Villadsen GE, Gregersen H. Spontaneous and bolus-induced motility in the chronically obstructed guinea-pig small intestine in vitro. Dig Dis Sci 2008; 53:413-20. [PMID: 17562174 DOI: 10.1007/s10620-007-9865-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/21/2007] [Accepted: 05/01/2007] [Indexed: 12/23/2022]
Abstract
Partial obstruction of the small intestine results in dysmotility and morphometric changes proximal to the site of obstruction. However, our understanding of the relation between the morphometric remodeling and change in the motility pattern during chronic obstruction is sparse. The aim of this study was to investigate the effect of partial chronic intestinal obstruction on motility, morphology, and collagen content proximal and distal to the site of obstruction. Twenty guinea-pigs with partial intestinal obstruction and eight sham-operated controls lived for four weeks. Spontaneous and bolus-induced motility was recorded in isolated intestinal segments proximal and distal to the site of obstruction using a perfused low-compliance pressure-measuring system in vitro. After the motility experiments, the specimens were fixed at 2 kPa luminal distension pressure and sampled for histomorphometric determination of luminal radius, layer thickness, and wall thickness. Total wall collagen was also determined. The area under the curve (AUC) of spontaneous contractions and the amplitude, frequency, and AUC for the bolus-induced motility were higher in the proximal segments of the banded animals compared to distal segments and to the intestinal segments in the control animals (P < 0.05). The radius-to-thickness ratio was lowest in the proximal segments of the obstructed animals (P < 0.01). The collagen content was three times higher proximal to the site of obstruction when compared to distal locations and to the controls (P < 0.01). The AUC at 2 ml bolus injections plotted against the radius-to-thickness ratio showed a strong association (r = 0.97 for control, and r = 0.99 for obstruction, P < 0.01). No correlation was found between the collagen content and AUC. In conclusion, partial intestinal obstruction in guinea pigs caused pronounced changes in morphology and motility. An association was found between the radius-to-thickness ratio and bolus-induced motility.
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Affiliation(s)
- Jan Henrik Storkholm
- Center of Excellence in Visceral Biomechanics and Pain, Aalborg Hospital, DK-9100 Aalborg, Denmark
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Bertoni S, Gabella G, Ballabeni V, Ghirardi A, Impicciatore M, Barocelli E. Plasticity of rat small intestine after removal of a chronic mechanical obstruction. Neurogastroenterol Motil 2006; 18:862-72. [PMID: 16918766 DOI: 10.1111/j.1365-2982.2006.00818.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Chronic intestinal obstruction is associated with morphological changes and functional disorders clinically reported and experimentally documented in laboratory animals. In contrast, little is known about the properties of the hypertrophied intestine after removal of the obstruction. In the present study, we removed the ileal obstruction previously applied to the ileum of rats and, after 1 or 2 weeks, studied in vitro the motor responses of de-obstructed segments of intestine to pharmacological or electrical field stimulation (EFS). By 2 weeks after de-obstruction, maximal contractile responses to receptor (acetylcholine) and non-receptor (K(+)) mediated stimuli were comparable in operated and control tissues; furthermore, the loss of sensitivity to nitric oxide (NO) unmasked in obstructed tissues was, after de-obstruction, replaced by supersensitivity to exogenous NO and vasoactive intestinal polypeptide, probably acting through cyclic nucleotide-independent pathways. Despite the complete recovery of smooth muscle responses, neurogenic contractions remained impaired in de-obstructed tissue; however, the equal contribution of cholinergic/peptidergic components to EFS responses could represent a sign of gradual but delayed recovery of enteric neurotransmission.
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Affiliation(s)
- S Bertoni
- Department of Pharmacological, Biological and Applied Chemical Sciences, University of Parma, Parma, Italy
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Bertoni S, Gabella G, Ghizzardi P, Ballabeni V, Impicciatore M, Lagrasta C, Arcari ML, Barocelli E. Motor responses of rat hypertrophic intestine following chronic obstruction. Neurogastroenterol Motil 2004; 16:365-74. [PMID: 15198659 DOI: 10.1111/j.1365-2982.2004.00510.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The present work aims at investigating the changes in motor responsiveness of rat intestine hypertrophied by chronic mechanical obstruction. Motor responses to pharmacological agents and electrical field stimulation (EFS) were studied in hypertrophic ileal segments excised from rats subjected to experimental stenosis (n = 20) and compared with responses of control tissues from sham-operated animals (n = 20). Spontaneous motility and contractile responses to exogenous agents (KCl, acetylcholine and substance P) and EFS (10-s trains every minute, 120 mA, 0.5 ms, 1-10 Hz) were increased in hypertrophic longitudinal segments; however, normalization of motor responses to tissue wet weight revealed a remarkable reduction of contractile efficiency in hypertrophied tissues coupled with a loss of sensitivity to nitric oxide-mediated relaxation. Furthermore, EFS under non-adrenergic non-cholinergic (NANC) conditions unveiled a major role of the cholinergic component over the peptidergic one in the neurogenic contraction of hypertrophic intestine. On the whole, hypertrophic intestinal growth emerges as a dynamic process entailing adaptation of smooth muscle and neuronal structures to the increased functional load imposed by lumen obstruction.
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Affiliation(s)
- S Bertoni
- Department of Pharmacological, Biological and Applied Chemical Sciences, University of Parma, Parma, Italy
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Meylan M, Zanolari P, Steiner A. Myoelectric activity in the intestine of cows with strangulating obstruction of the distal small intestine. J Vet Intern Med 2003; 17:571-8. [PMID: 12892311 DOI: 10.1111/j.1939-1676.2003.tb02481.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Myoelectric activity in 2 cows instrumented with permanent electrodes in the ileum, cecum, proximal loop of the ascending colon (PLAC), and spiral colon was analyzed after an obstruction developed in the distal small intestine. Results were compared with patterns from a group of 7 normal cows. Myoelectric activity in the ileum immediately orad to the occlusion was characterized by abolition of the migrating myoelectric complex (MMC) and a constant pattern of strong spike bursts of long duration. Cyclic activity was present in all parts of the large intestine, and propagation of phase III activity was evident from proximal to distal. A slight degree of disorganization in phase III propagation was restricted to the spiral colon. Activity cycles tended to be shorter in the cecum and PLAC of both cows with colic than in normal cows, and the intensity of spiking activity was generally lower. Changes in duration of the MMC in the spiral colon (bovine colonic MMC, bcMMC) were inconsistent, but the intensity of spiking activity tended to be lower in phases I and II of both cows compared to controls. The organization of phase III in several spindles typical of the bovine spiral colon was not disrupted, but phase IV of the bcMMC occurred only infrequently. Organized cyclic activity occurred in the large intestine of both cows despite complete disruption of the small intestinal MMC, indicating the presence of mechanisms able to initiate and regulate coordinated myoelectric patterns in the large intestine independent of the small intestine.
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Affiliation(s)
- Mireille Meylan
- Clinic for Ruminants, Department for Clinical Veterinary Medicine, University of Berne, Switzerland.
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Kroening KD, Zimmerman NP, Bass P, Oaks JA. Partial characterization of a tapeworm-secreted signal factor inducing sustained spike potentials in the smooth muscle of the rat small intestine. J Parasitol 2002; 88:227-31. [PMID: 12053990 DOI: 10.1645/0022-3395(2002)088[0227:pcoats]2.0.co;2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
The rat tapeworm Hymenolepis diminuta alters the myoelectric activity of the small intestine. To determine if secreted factors from the tapeworm are responsible for these alterations of intestinal smooth muscle activity, tapeworm-conditioned medium (TCM) obtained from in vitro culture was infused via an indwelling cannula into the duodenum of an uninfected rat. Myoelectric recordings were analyzed for sustained spike potentials (SSP) and repetitive bursts of action potentials (RBAP), the previously characterized tapeworm modifications of the normal interdigestive myoelectric pattern. Results indicated that TCM initiated SSP, but not RBAP in the intestine of the uninfected rat. The SSP-inducing signal factor activity, present in TCM, was retained after boiling, prolonged freezing, proteinase treatment, and passage through a 10-kDa exclusion filter. The signal factor was soluble in the aqueous phase on lipid extraction. It was concluded that the SSP-inducing signal factor is a nonproteinaceous, heat-resistant, low-molecular weight, water soluble molecule.
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Affiliation(s)
- K Dubear Kroening
- Department of Comparative Biosciences, School of Veterinary Medicine, Madison, Wisconsin 53706-1102, USA
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Rodriguez L, Calabuig R, LaRocco M, Moody FG, Miller TA. Bacterial flora of the gastrointestinal tract of opossums. Vet Microbiol 1992; 30:289-95. [PMID: 1557901 DOI: 10.1016/0378-1135(92)90122-a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The bacterial flora of the stomach, small intestine, cecum and bile from 20 healthy opossums (Didelphis virginiana) captured from the wild was studied. Results showed that their gastrointestinal flora was similar to that found in other small mammals but, in addition, opossums are heavily colonized by Salmonella spp., which might adversely affect their adequacy as laboratory animals for some experimental protocols.
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Affiliation(s)
- L Rodriguez
- Department of Surgery, University of Texas Medical School, Houston 77030
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Hypertrophic smooth muscle in the partially obstructed opossum esophagus. The model: histological and ultrastructural observations. Gastroenterology 1991; 100:853-64. [PMID: 2001825 DOI: 10.1016/0016-5085(91)90256-k] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Obstruction is a complication of many esophageal diseases, but the morphological changes occurring in the obstructed esophagus are poorly understood. We developed a model of esophageal obstruction in the American opossum, Didelphis virginiana. A nonconstricting band around the gastroesophageal junction led to esophageal distention and tortuosity in the weeks following its placement. Despite a marked increase of the esophageal circumference, the esophageal wall was not thinned, and the circular muscle layer had actually increased its thickness. This was due to an increase in the size of individual smooth muscle cells with proportional increases in the cell surface area and volume. The electron density of hypertrophic smooth muscle cells varied much more than that of normal esophageal smooth muscle cells. As cell size increased, the tissue became more compact and the size of the extracellular space decreased. Also, the extracellular space was filled by an amorphous electron-dense material. Additional changes in the structure of hypertrophic smooth muscle cells included prominent intermediate filaments in the vicinity of thick filaments. There was no difference in the structure of the hypertrophic smooth muscle at 4 weeks and at 8 weeks after placement of the band. The morphological features described here resemble those seen in human esophageal spasm and achalasia of humans and could affect esophageal smooth muscle function.
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Abstract
Smooth muscles of viscera undergo a large increase in volume when there is a chronic, partial obstruction impairing the flow of lumenal contents. Hypertrophy of smooth muscle occurs in various medical conditions and several methods are available for inducing it experimentally in laboratory animals, especially in urinary bladder, small intestine and ureter. The hypertrophic response differs somewhat with the type of organ, the animal species, the age of the subject, and the experimental procedure. Ten- to fifteen-fold increases in muscle volume develop within a few weeks in the urinary bladder or the ileum of adult animals, a growth that would not have occurred in the lifespan of the animal without the experimental intervention. The general architecture of the muscle and the boundaries with adjacent tissues are well preserved. In intestinal hypertrophy, muscle cells increase in number: mitoses are found in mature, fully differentiated muscle cells. Cell division by full longitudinal splitting of muscle cells may also occur. Enlargement of muscle cells accounts for most of the muscle hypertrophy. The hypertrophic muscle cell has an irregular profile with deep indentations of the cell membrane, bearing caveolae and dense bands; however, the cell surface grows less than the cell volume (reduction of surface-to-volume ratio). The nucleus is crenated and is much less enlarged than the cell (reduction of the nucleo-plasmatic ratio). Mitochondria grow in number but in some muscles their spatial density decreases; intermediate filaments increase more than myofilaments. The spatial density of sarcoplasmic reticulum is generally increased. In the hypertrophic intestine, gap junctions increase in number and size; in the bladder, gap junctions are absent both in control and in hypertrophy. Thus the hypertrophic muscle cell is not only larger than a control cell, but has a different pattern of its structural components. Extensive neo-angiogenesis maintains a good blood supply to the hypertrophic muscle. The density of innervation is much decreased in the hypertrophic intestine, whereas it appears well maintained in the bladder. Neuronal enlargement is found in the intramural ganglia of the intestine and in the pelvic ganglion. The mechanisms involved in hypertrophic growth are unknown. Three possible factors, mechanical factors, especially stretch, altered nerve discharge, and trophic factors are discussed.
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Affiliation(s)
- G Gabella
- Department of Anatomy, University College London, United Kingdom
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Morel P, Alexander-Williams J, Rohner A. Relation between flow-pressure-diameter studies in experimental stenosis of rabbit and human small bowel. Gut 1990; 31:875-8. [PMID: 2387509 PMCID: PMC1378613 DOI: 10.1136/gut.31.8.875] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Patients with inflammatory and ischaemic bowel diseases seem to tolerate narrowing of the gut lumen to a critical degree of stenosis without obstructive symptoms. To determine the physical factors involved in bowel occlusion, we created an experimental model using New Zealand rabbits in acute experiments under general anaesthesia. At operation a loop of small bowel was isolated and canulated, proximally for perfusion and pressure recording and distally to monitor flow. Having established the physiological pressure and flow conditions in a normal loop of gut, a stenosis was created using circular adjustable rings of determined widths. Pressure and flow were measured constantly and the variables studied were luminal diameter, stenosis length, and perfusate viscosity. This experimental model was reproduced using resected segments of human small bowel. We found a critical point- at 60% of the original diameter-down to which the small bowel is able to maintain normal flow. At a diameter smaller than this, the physiological parameters are rapidly altered up to the point of complete obstruction. In the rabbit model bowel rupture occurs at 30% of the initial size. Increased viscosity of the fluid and length of the stenosis alter this critical point inducing a larger critical diameter. We did not observe any cumulative effect of multiple identical stenoses.
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Affiliation(s)
- P Morel
- General Hospital, Birmingham
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Quigley EM, Thompson JS, Lof J. Disruption of canine jejunal interdigestive myoelectrical activity by artificial ileocolonic sphincter. Studies of intestinal motor response to surgically fashioned sphincter substitute. Dig Dis Sci 1989; 34:1434-42. [PMID: 2766910 DOI: 10.1007/bf01538082] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
We studied the effects of an ileocolonic sphincter substitute on canine small intestine motor activity. Recordings of fasting and postprandial myoelectrical activity were performed in three groups of animals in whom the following procedures had been performed: (1) electrode placement alone, intestinal continuity undisturbed (controls); (2) ileocolonic sphincter substitute fashioned in mid-jejunum; and (3) transection and reanastomosis at a similar location in mid-jejunum. Transection alone resulted in a decrease in slow-wave frequency, a shortening of the period of the interdigestive myoelectrical complex (IDMEC) and a prolongation of phase III of the IDMEC in the jejunum distal to the site of transection. The IDMEC period was also shorter at proximal electrode sites, but the incidence of IDMEC phase III complexes was similar on either side of the transection. However, in those animals in whom a sphincter substitute had been fashioned at the site of the transection, the incidence of IDMEC phase III complexes was significantly suppressed in the proximal intestine; IDMEC phase III frequency per hour (mean +/- SD transection vs sphincter substitute) was 0.59 +/- 0.20 vs 0.23 +/- 0.24, P less than 0.002; 0.61 +/- 0.24 vs 0.28 +/- 0.30, P less than 0.006; 0.61 +/- 0.24 vs 0.29 +/- 0.30, P = 0.008, at electrodes 10, 35, and 85 cm proximal to the sphincter substitute, respectively. In addition, the sphincter-substitute animals alone demonstrated, during fasting, recurrent propagated bursts of spike clusters and occasional prolonged spike bursts in electrodes proximal to the sphincter substitute.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- E M Quigley
- Department of Internal Medicine, Omaha Veterans Administration Medical Center, NE
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