We summarize from previous works the functions of circular vs. longitudinal muscle in esophageal peristaltic bolus transport using a mix of experimental data, the conservation laws of mechanics and mathematical modeli...We summarize from previous works the functions of circular vs. longitudinal muscle in esophageal peristaltic bolus transport using a mix of experimental data, the conservation laws of mechanics and mathematical modeling. Whereas circular muscle tone generates radial closure pressure to create a local peristaltic closure wave, longitudinal muscle tone has two functions, one physiological with mechanical implications, and one purely mechanical. Each of these functions independently reduces the tension of individual circular muscle fibers to maintain closure as a consequence of shortening of longitudinal muscle locally coordinated with increasing circular muscle tone. The physiological function is deduced by combining basic laws of mechanics with concurrent measurements of intraluminal pressure from manometry, and changes in cross sectional muscle area from endoluminal ultrasound from which local longitudinal shortening (LLS) can be accurately obtained. The purely mechanical function of LLS was discovered from mathematical modeling of peristaltic esophageal transport with the axial wall motion generated by LLS. Physiologically, LLS concentrates circular muscle fibers where closure pressure is highest. However, the mechanical function of LLS is to reduce the level of pressure required to maintain closure. The combined physiological and mechanical consequences of LLS are to reduce circular muscle fiber tension and power by as much as 1/10 what would be requiredfor peristalsis without the longitudinal muscle layer, a tremendous benefit that may explain the existence of longitudinal muscle fiber in the gut. We also review what is understood of the role of longitudinal muscle in esophageal emptying, reflux and pathology.展开更多
The frequency and amplitude of gastric peristaltic wave were significantly changed in 15 subjects when Sibai (ST 2) and Neiting (ST 44) acupoints of the Stomach Channel of Foot-Yangming were punctured. The results dem...The frequency and amplitude of gastric peristaltic wave were significantly changed in 15 subjects when Sibai (ST 2) and Neiting (ST 44) acupoints of the Stomach Channel of Foot-Yangming were punctured. The results demonstrate that these acupoints are effective for treatment of stomach diseases, providing an experimental basis for the theory of channels and collaterals.展开更多
AIM To determine whether capsaicin infusion could influence heartburn perception and secondary peristalsis in patients with gastroesophageal reflux disease(GERD). METHODS Secondary peristalsis was performed with slow ...AIM To determine whether capsaicin infusion could influence heartburn perception and secondary peristalsis in patients with gastroesophageal reflux disease(GERD). METHODS Secondary peristalsis was performed with slow and rapid mid-esophageal injections of air in 10 patients with GERD. In a first protocol, saline and capsaicincontaining red pepper sauce infusions were randomly performed, whereas 2 consecutive sessions of capsaicin-containing red pepper sauce infusions were performed in a second protocol. Tested solutions including 5 m L of red pepper sauce diluted with 15 m L of saline and 20 m L of 0.9% saline were infused into the mid-esophagus via the manometric catheter at a rate of 10 mL /min with a randomized and doubleblind fashion. During each study protocol, perception of heartburn, threshold volumes and peristaltic parameters for secondary peristalsis were analyzed and compared between different stimuli.RESULTS Infusion of capsaicin significantly increased heartburn perception in patients with GERD(P < 0.001), whereas repeated capsaicin infusion significantly reduced heartburn perception(P = 0.003). Acute capsaicin infusion decreased threshold volume of secondary peristalsis(P = 0.001) and increased its frequency(P = 0.01) during rapid air injection. The prevalence of GERD patients with successive secondary peristalsis during slow air injection significantly increased after capsaicin infusion(P = 0.001). Repeated capsaicin infusion increased threshold volume of secondary peristalsis(P = 0.002) and reduced the frequency of secondary peristalsis(P = 0.02) during rapid air injection. CONCLUSION Acute esophageal exposure to capsaicin enhances heartburn sensation and promotes secondary peristalsis in gastroesophageal reflux disease, but repetitive capsaicin infusion reverses these effects.展开更多
Nanofluids have attracted many scientists due to their remarkable thermophysical properties.Small percentage of nanoparticles when added to conventional fluid significantly enhances the heat transfer features.Sustaina...Nanofluids have attracted many scientists due to their remarkable thermophysical properties.Small percentage of nanoparticles when added to conventional fluid significantly enhances the heat transfer features.Sustainability and efficiency of nanomaterials have key role in the advancement of nanotechnology.This article analyzes the Hall,Ohmic heating and velocity slip effects on the peristalsis of nanofluid.Convective boundary conditions and heat generation/absorption are considered to facilitate the heat transfer characteristics.Governing equations for the peristaltic flow through a curved channel are derived in curvilinear coordinates.The equations are numerically solved under the assumption of long wavelength and small Reynold number.It has been observed that nanofluid enhances the heat transfer rate and reduces the fluid temperature.Hartman number and Hall parameter show reverse behavior in fluid motion and heat transfer characteristics.In the presence of velocity slip,the pressure gradient rapidly decreases and dominant effect is seen in narrow portion of channel.展开更多
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 intralumi...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 am-plitude 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 [nonadrenergic 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 distensioninduced motility in non-obstructed tissues.展开更多
Orthogonal design was used to observe the gastrointestinal peristalsis in normal andatropine-treated mice after electroacupuncture was applied,singly or in combination,atNeiguan(P 6),Pishu(UB 20)and Zusanli(St 36).The...Orthogonal design was used to observe the gastrointestinal peristalsis in normal andatropine-treated mice after electroacupuncture was applied,singly or in combination,atNeiguan(P 6),Pishu(UB 20)and Zusanli(St 36).The results showed that:1)electroacupuncture has no significant effect on the gastrointestinal peristalsis in normalmice;2)Pishu(UB 20)was significantly antagonistic to Zusanli(St 36)in normal mice;3)the decreased gastrointestinal peristalsis in atropine-treated mice was markedly promotedby electroacupuncture at Zusanli(St 36);and 4)Neiguan(P 6)was significantlyantagonistic to Pishu(UB 20)in atropine-treated mice.The results indicated that thereciprocal actions among acupoints should be taken into consideration for pointprescription.展开更多
This paper aims to examine variable viscosity effects on peristalsis of Sisko fluids in a curved channel with compliant characteristics. Viscous dissipation in a heat transfer is studied. The resulting problems are so...This paper aims to examine variable viscosity effects on peristalsis of Sisko fluids in a curved channel with compliant characteristics. Viscous dissipation in a heat transfer is studied. The resulting problems are solved using perturbation and numerical schemes to show qualitatively similar responses for velocity and temperature. A streamline phenomenon is also considered.展开更多
AIM: To investigate dysfunctions in esophageal peristalsis and sensation in patients with Barrett’s esophagus following acid infusion using endoscopy-based testing.
Developing an oral in situ-forming hydrogel that targets the inflamed intestine to suppress bleeding ulcers and alleviate intestinal inflammation is crucial for effectively treating ulcerative colitis(UC).Here,inspire...Developing an oral in situ-forming hydrogel that targets the inflamed intestine to suppress bleeding ulcers and alleviate intestinal inflammation is crucial for effectively treating ulcerative colitis(UC).Here,inspired by sandcastle worm adhesives,we proposed a water-immiscible coacervate(EMNs-gel)with a programmed coacervate-to-hydrogel transition at inflammatory sites composed of dopa-rich silk fibroin matrix containing embedded inflammation-responsive core-shell nanoparticles.Driven by intestinal peristalsis,the EMNs-gel can be actuated forward and immediately transform into a hydrogel once contacting with the inflamed intestine to yield strong tissue adhesion,resulting from matrix metalloproteinases(MMPs)-triggered release of Fe3+from embedded nanoparticles and rearrangement of polymer network of EMNs-gel on inflamed intestine surfaces.Extensive in vitro experiments and in vivo UC models confirmed the preferential hydrogelation behavior of EMNs-gel to inflamed intestine surfaces,achieving highly effective hemostasis,and displaying an extended residence time(48 h).This innovative EMNs-gel provides a non-invasive solution that accurately suppresses severe bleeding and improves intestinal homeostasis in UC,showcasing great potential for clinical applications.展开更多
AIM: To compare the efficacy and safety of sedation protocols for endoscopic submucosal dissection(ESD) between dexmedetomidine-remifentanil and propofolremifentanil.METHODS: Fifty-nine patients scheduled for ESD were...AIM: To compare the efficacy and safety of sedation protocols for endoscopic submucosal dissection(ESD) between dexmedetomidine-remifentanil and propofolremifentanil.METHODS: Fifty-nine patients scheduled for ESD were randomly allocated into a dexmedetomidineremifentanil(DR) group or a propofol-remifentanil(PR) group. To control patient anxiety, dexmedetomidine or propofol was infused to maintain a score of 4-5 on the Modified Observer's Assessment of Alertness/Sedation scale. Remifentanil was infused continuously at a rate of 6 μg/kg per hour in both groups. The ease of advancing the scope into the throat, gastric motility grading, and satisfaction of the endoscopist and patient were assessed. Hemodynamic variables and hypoxemic events were compared to evaluate patient safety.RESULTS: Demographic data were comparable between the groups. The hemodynamic variables and pulse oximetry values were stable during the procedure in both groups despite a lower heart rate in the DR group. No oxygen desaturation events occurred in either group. Although advancing the scope into the throat was easier in the PR group("very easy" 24.1% vs 56.7%, P = 0.010), gastric motility was moresuppressed in the DR group("no + mild" 96.6% vs 73.3%, P = 0.013). The endoscopists felt that the procedure was more favorable in the DR group("very good + good" 100% vs 86.7%, P = 0.042), whereas patient satisfaction scores were comparable between the groups. En bloc resection was performed 100% of the time in both groups, and the complete resection rate was 94.4% in the DR group and 100% in the PR group(P = 0.477). CONCLUSION: The efficacy and safety of dexmedetomidine and remifentanil were comparable to propofol and remifentanil during ESD. However, the endoscopists favored dexmedetomidine perhaps due to lower gastric motility.展开更多
Interstitial cells of Cajal (ICC) are important players in the symphony of gut motility. They have a very signif icant physiological role orchestrating the normal peristaltic activity of the digestive system. They are...Interstitial cells of Cajal (ICC) are important players in the symphony of gut motility. They have a very signif icant physiological role orchestrating the normal peristaltic activity of the digestive system. They are the pacemaker cells in gastrointestinal (GI) muscles. Absence, reduction in number or altered integrity of the ICC network may have a dramatic effect on GI system motility. More understanding of ICC physiology will foster advances in physiology of gut motility which will help in a future breakthrough in the pharmacological interventions to restore normal motor function of GI tract. This mini review describes what is known about the physiologic function and role of ICCs in GI system motility and in a variety of GI system motility disorders.展开更多
Achalasia cardia is one of the common causes of motor dysphagia.Though the disease was first described more than 300 years ago,exact pathogenesis of this condition still remains enigmatic.Pathophysiologically,achalasi...Achalasia cardia is one of the common causes of motor dysphagia.Though the disease was first described more than 300 years ago,exact pathogenesis of this condition still remains enigmatic.Pathophysiologically,achalasia cardia is caused by loss of inhibitory ganglion in the myenteric plexus of the esophagus.In the initial stage,degeneration of inhibitory nerves in the esophagus results in unopposed action of excitatory neurotransmitters such as acetylcholine,resulting in high amplitude non-peristaltic contractions(vigorous achalasia);progressive loss of cholinergic neurons over time results in dilation and low amplitude simultaneous contractions in the esophageal body(classic achalasia).Since the initial description,several studies have attempted to explore initiating agents that may cause the disease,such as viral infection,other environmental factors,autoimmunity,and genetic factors.Though Chagas disease,which mimics achalasia,is caused by an infective agent,available evidence suggests that infection may not be an independent cause of primary achalasia.A genetic basis for achalasia is supported by reports showing occurrence of disease in monozygotic twins,siblings and other first-degree relatives and occurrence in association with other genetic diseases such as Down's syndrome and Parkinson's disease.Polymorphisms in genes encoding for nitric oxide synthase,receptors for vasoactive intestinal peptide,interleukin 23 and the ALADIN gene have been reported.However,studies on larger numbers of patients and controls from different ethnic groups are needed before definite conclusions can be obtained.Currently,the disease is believed to be multi-factorial,with autoimmune mechanisms triggered by infection in a genetically predisposed individual leading to degeneration of inhibitory ganglia in the wall of the esophagus.展开更多
AIM:To investigate the therapeutic effect of Schistosoma mansoni(S.mansoni) soluble worm proteins on gastrointestinal motility disturbances during experimental colitis in mice. METHODS:Colitis was induced by intrarect...AIM:To investigate the therapeutic effect of Schistosoma mansoni(S.mansoni) soluble worm proteins on gastrointestinal motility disturbances during experimental colitis in mice. METHODS:Colitis was induced by intrarectal injection of trinitrobenzene sulphate(TNBS) and 6 h later,mice were treated ip with S.mansoni proteins.Experiments were performed 5 d after TNBS injection.Inflammationwas quantified using validated inflammation parameters. Gastric emptying and geometric center were measured to assess in vivo gastrointestinal motility.Peristaltic activity of distal colonic segments was studied in vitro using a modified Trendelenburg set-up.Cytokine profiles of T-lymphocytes isolated from the colon were determined by real time reverse transcriptase-polymerase chain reaction. RESULTS:Intracolonic injection of TNBS caused severe colitis.Treatment with S.mansoni proteins significantly ameliorated colonic inflammation after 5 d.TNBS did not affect gastric emptying but significantly decreased the geometric center and impaired colonic peristaltic activity 5 d after the induction of colitis.Treatment with S.mansoni proteins ameliorated these in vivo and in vitro motility disturbances.In addition,TNBS injection caused a downregulation of effector T cell cytokines after 5 d,whereas a S.mansoni protein effect was no longer observed at this time point. CONCLUSION:Treatment with S.mansoni proteins attenuated intestinal inflammation and ameliorated motility disturbances during murine experimental colitis.展开更多
AIM: To demonstrate the optimal surgical procedure for gastroesophageal reflux disease. METHODS: The electronic databases of Medline, Elsevier, Springerlink and Embase over the last 16 years were searched. All clinica...AIM: To demonstrate the optimal surgical procedure for gastroesophageal reflux disease. METHODS: The electronic databases of Medline, Elsevier, Springerlink and Embase over the last 16 years were searched. All clinical trials involved in the outcomes of laparoscopic Nissen fundoplication (LNF) and laparoscopic Toupet fundoplication (LTF) were identified. The data of assessment in benefits and adverse results of LNF and LTF were extracted and compared using metaanalysis. RESULTS: We ultimately identified a total of 32 references reporting nine randomized controlled trials, eight prospective cohort trials and 15 retrospective trials. These studies reported a total of 6236 patients, of whom 4252 (68.18%) underwent LNF and 1984 (31.82%) underwent LTF. There were no differences between LNF and LTF in patients' satisfaction, perioperative complications, postoperative heartburn, refluxrecurrence and reoperation. Both LNF and LTF enhanced the function of lower esophageal sphincter and improved esophagitis. The postoperative dysphagia, gasbloating syndrome, inability to belch and the need for dilatation after LNF were more common than after LTF. Subgroup analyses showed that dysphagia after LNF and LTF was similar in patients with normal esophageal peristalsis (EP), but occurred more frequently in patients with weak EP after LNF than after LTF. Furthermore, patients with normal EP after LNF still had a higher risk of developing dysphagia than did patients with abnormal EP after LTF.CONCLUSION: Compared with LNF, LTF offers equivalent symptom relief and reduces adverse results.展开更多
In order to relieve the abdominal distension and other discomforts due to gastrointestinal dysfunction after abdominal operations, the patients were treated by auricular-plaster therapy plus acupuncture at Zusanli (ST...In order to relieve the abdominal distension and other discomforts due to gastrointestinal dysfunction after abdominal operations, the patients were treated by auricular-plaster therapy plus acupuncture at Zusanli (ST 36). 12 (92.4%) of the 13 cases in the treatment group showed recovery of normal peristalsis within 72 hours after operations, while that in 13 cases of the control group was 46.1%, indicating that auricular-plaster therapy plus acupuncture at Zusanli (ST 36) may promote postoperative recovery of the intestinal function.展开更多
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, esophagea...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.展开更多
＂ Analysis is performed to study the slip effects on the peristaltic flow of non-Newtonian fluid in a curved channel with wall properties. The resulting nonlinear partial differential equations are transformed to a s...＂ Analysis is performed to study the slip effects on the peristaltic flow of non-Newtonian fluid in a curved channel with wall properties. The resulting nonlinear partial differential equations are transformed to a single ordinary differential equation in a stream function by using the assumptions of long wavelength and low Reynolds number. This differential equation is solved numerically by employing the built-in routine for solving nonlinear boundary value problems （BVPs） through the software Mathematica. In addition, the analytic solutions for small Deborah number are computed with a regular perturbation technique. It is noticed that the symmetry of bolus is destroyed in a curved channel. An intensification in the slip effect results in a larger magnitude of axial velocity. Further, the size and circulation of the trapped boluses increase with an increase in the slip parameter. Different from the case of planar channel, the axial velocity profiles are tilted towards the lower part of the channel. A comparative study between analytic and numerical solutions shows excellent agreement.展开更多
Investigation concerning peristaltic motion of couple stress fluid is made. An incompressible couple stress fluid occupies the porous medium. Mathematical anal- ysis is presented through large wavelength and low Reyno...Investigation concerning peristaltic motion of couple stress fluid is made. An incompressible couple stress fluid occupies the porous medium. Mathematical anal- ysis is presented through large wavelength and low Reynolds number. Exact analytical expressions of axial velocity, volume flow rate, pressure gradient, and stream function are calculated as a function of couple stress parameter. The essential feature of the analysis is a full description of influence of couple stress parameter and permeability parameter on the pressure, frictional force, mechanical efficiency, and trapping.展开更多
The peristaltic transport of a magnetohydrodynamic （MHD） fluid is exam- ined for both symmetric and asymmetric channels. Hall and ion slip effects are taken into account. The heat transfer is analyzed by considering...The peristaltic transport of a magnetohydrodynamic （MHD） fluid is exam- ined for both symmetric and asymmetric channels. Hall and ion slip effects are taken into account. The heat transfer is analyzed by considering the effects of viscous and Ohmic dissipations. The relevant flow problems are first modeled, and then the closed form solutions are constructed under the assumptions of long wavelength and low Reynolds number. The solutions are analyzed through graphical illustration. It is noted that the velocity increases but the temperature decreases with the increases in the Hall and ion slip parameters. The axial pressure gradient is less in magnitude in the presence of Hall and ion slip currents. The Hall and ion slip effects are to decrease the maximum pres- sure against which peristalsis works as a pump. The free pumping flux decreases with the increases in the Hall and ion slip parameters. The increases in the Hall and ion slip parameters result in an increase in the size of the trapped bolus.展开更多
In this investigation,we have studied the peristaltic fluid flow in an asymmetric channel with convective walls.Fourth grade fluid model has been utilized in view of the fact that the results of all other differential...In this investigation,we have studied the peristaltic fluid flow in an asymmetric channel with convective walls.Fourth grade fluid model has been utilized in view of the fact that the results of all other differential type models can be deduced as the special case.Combined effects of heat and mass transfer are considered.The thermophoresis effects occur in the energy equation.Convective heat and mass boundary conditions have been given special attention.Long wave length and low Reynolds number approximations are utilized for the simplifications.Approximate analytic solutions for the velocity,temperature and concentration profiles are calculated using perturbation technique and elaborated in the form of graphical observations for various physical quantities.展开更多
文摘We summarize from previous works the functions of circular vs. longitudinal muscle in esophageal peristaltic bolus transport using a mix of experimental data, the conservation laws of mechanics and mathematical modeling. Whereas circular muscle tone generates radial closure pressure to create a local peristaltic closure wave, longitudinal muscle tone has two functions, one physiological with mechanical implications, and one purely mechanical. Each of these functions independently reduces the tension of individual circular muscle fibers to maintain closure as a consequence of shortening of longitudinal muscle locally coordinated with increasing circular muscle tone. The physiological function is deduced by combining basic laws of mechanics with concurrent measurements of intraluminal pressure from manometry, and changes in cross sectional muscle area from endoluminal ultrasound from which local longitudinal shortening (LLS) can be accurately obtained. The purely mechanical function of LLS was discovered from mathematical modeling of peristaltic esophageal transport with the axial wall motion generated by LLS. Physiologically, LLS concentrates circular muscle fibers where closure pressure is highest. However, the mechanical function of LLS is to reduce the level of pressure required to maintain closure. The combined physiological and mechanical consequences of LLS are to reduce circular muscle fiber tension and power by as much as 1/10 what would be requiredfor peristalsis without the longitudinal muscle layer, a tremendous benefit that may explain the existence of longitudinal muscle fiber in the gut. We also review what is understood of the role of longitudinal muscle in esophageal emptying, reflux and pathology.
文摘The frequency and amplitude of gastric peristaltic wave were significantly changed in 15 subjects when Sibai (ST 2) and Neiting (ST 44) acupoints of the Stomach Channel of Foot-Yangming were punctured. The results demonstrate that these acupoints are effective for treatment of stomach diseases, providing an experimental basis for the theory of channels and collaterals.
文摘AIM To determine whether capsaicin infusion could influence heartburn perception and secondary peristalsis in patients with gastroesophageal reflux disease(GERD). METHODS Secondary peristalsis was performed with slow and rapid mid-esophageal injections of air in 10 patients with GERD. In a first protocol, saline and capsaicincontaining red pepper sauce infusions were randomly performed, whereas 2 consecutive sessions of capsaicin-containing red pepper sauce infusions were performed in a second protocol. Tested solutions including 5 m L of red pepper sauce diluted with 15 m L of saline and 20 m L of 0.9% saline were infused into the mid-esophagus via the manometric catheter at a rate of 10 mL /min with a randomized and doubleblind fashion. During each study protocol, perception of heartburn, threshold volumes and peristaltic parameters for secondary peristalsis were analyzed and compared between different stimuli.RESULTS Infusion of capsaicin significantly increased heartburn perception in patients with GERD(P < 0.001), whereas repeated capsaicin infusion significantly reduced heartburn perception(P = 0.003). Acute capsaicin infusion decreased threshold volume of secondary peristalsis(P = 0.001) and increased its frequency(P = 0.01) during rapid air injection. The prevalence of GERD patients with successive secondary peristalsis during slow air injection significantly increased after capsaicin infusion(P = 0.001). Repeated capsaicin infusion increased threshold volume of secondary peristalsis(P = 0.002) and reduced the frequency of secondary peristalsis(P = 0.02) during rapid air injection. CONCLUSION Acute esophageal exposure to capsaicin enhances heartburn sensation and promotes secondary peristalsis in gastroesophageal reflux disease, but repetitive capsaicin infusion reverses these effects.
文摘Nanofluids have attracted many scientists due to their remarkable thermophysical properties.Small percentage of nanoparticles when added to conventional fluid significantly enhances the heat transfer features.Sustainability and efficiency of nanomaterials have key role in the advancement of nanotechnology.This article analyzes the Hall,Ohmic heating and velocity slip effects on the peristalsis of nanofluid.Convective boundary conditions and heat generation/absorption are considered to facilitate the heat transfer characteristics.Governing equations for the peristaltic flow through a curved channel are derived in curvilinear coordinates.The equations are numerically solved under the assumption of long wavelength and small Reynold number.It has been observed that nanofluid enhances the heat transfer rate and reduces the fluid temperature.Hartman number and Hall parameter show reverse behavior in fluid motion and heat transfer characteristics.In the presence of velocity slip,the pressure gradient rapidly decreases and dominant effect is seen in narrow portion of channel.
文摘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 am-plitude 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 [nonadrenergic 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 distensioninduced motility in non-obstructed tissues.
文摘Orthogonal design was used to observe the gastrointestinal peristalsis in normal andatropine-treated mice after electroacupuncture was applied,singly or in combination,atNeiguan(P 6),Pishu(UB 20)and Zusanli(St 36).The results showed that:1)electroacupuncture has no significant effect on the gastrointestinal peristalsis in normalmice;2)Pishu(UB 20)was significantly antagonistic to Zusanli(St 36)in normal mice;3)the decreased gastrointestinal peristalsis in atropine-treated mice was markedly promotedby electroacupuncture at Zusanli(St 36);and 4)Neiguan(P 6)was significantlyantagonistic to Pishu(UB 20)in atropine-treated mice.The results indicated that thereciprocal actions among acupoints should be taken into consideration for pointprescription.
文摘This paper aims to examine variable viscosity effects on peristalsis of Sisko fluids in a curved channel with compliant characteristics. Viscous dissipation in a heat transfer is studied. The resulting problems are solved using perturbation and numerical schemes to show qualitatively similar responses for velocity and temperature. A streamline phenomenon is also considered.
文摘AIM: To investigate dysfunctions in esophageal peristalsis and sensation in patients with Barrett’s esophagus following acid infusion using endoscopy-based testing.
基金Chongqing Postdoctoral International Exchange Training Program(7820100997)Fundamental Research Funds for Central Universities(Nos.SWU-XDPY22010)+2 种基金National College Students Innovation and Entrepreneurship Training Program(202310635114)National Natural Science Foundation of China(No.81703424),Chongqing Graduate Student Research Innovation Project(CYB21121).
文摘Developing an oral in situ-forming hydrogel that targets the inflamed intestine to suppress bleeding ulcers and alleviate intestinal inflammation is crucial for effectively treating ulcerative colitis(UC).Here,inspired by sandcastle worm adhesives,we proposed a water-immiscible coacervate(EMNs-gel)with a programmed coacervate-to-hydrogel transition at inflammatory sites composed of dopa-rich silk fibroin matrix containing embedded inflammation-responsive core-shell nanoparticles.Driven by intestinal peristalsis,the EMNs-gel can be actuated forward and immediately transform into a hydrogel once contacting with the inflamed intestine to yield strong tissue adhesion,resulting from matrix metalloproteinases(MMPs)-triggered release of Fe3+from embedded nanoparticles and rearrangement of polymer network of EMNs-gel on inflamed intestine surfaces.Extensive in vitro experiments and in vivo UC models confirmed the preferential hydrogelation behavior of EMNs-gel to inflamed intestine surfaces,achieving highly effective hemostasis,and displaying an extended residence time(48 h).This innovative EMNs-gel provides a non-invasive solution that accurately suppresses severe bleeding and improves intestinal homeostasis in UC,showcasing great potential for clinical applications.
文摘AIM: To compare the efficacy and safety of sedation protocols for endoscopic submucosal dissection(ESD) between dexmedetomidine-remifentanil and propofolremifentanil.METHODS: Fifty-nine patients scheduled for ESD were randomly allocated into a dexmedetomidineremifentanil(DR) group or a propofol-remifentanil(PR) group. To control patient anxiety, dexmedetomidine or propofol was infused to maintain a score of 4-5 on the Modified Observer's Assessment of Alertness/Sedation scale. Remifentanil was infused continuously at a rate of 6 μg/kg per hour in both groups. The ease of advancing the scope into the throat, gastric motility grading, and satisfaction of the endoscopist and patient were assessed. Hemodynamic variables and hypoxemic events were compared to evaluate patient safety.RESULTS: Demographic data were comparable between the groups. The hemodynamic variables and pulse oximetry values were stable during the procedure in both groups despite a lower heart rate in the DR group. No oxygen desaturation events occurred in either group. Although advancing the scope into the throat was easier in the PR group("very easy" 24.1% vs 56.7%, P = 0.010), gastric motility was moresuppressed in the DR group("no + mild" 96.6% vs 73.3%, P = 0.013). The endoscopists felt that the procedure was more favorable in the DR group("very good + good" 100% vs 86.7%, P = 0.042), whereas patient satisfaction scores were comparable between the groups. En bloc resection was performed 100% of the time in both groups, and the complete resection rate was 94.4% in the DR group and 100% in the PR group(P = 0.477). CONCLUSION: The efficacy and safety of dexmedetomidine and remifentanil were comparable to propofol and remifentanil during ESD. However, the endoscopists favored dexmedetomidine perhaps due to lower gastric motility.
文摘Interstitial cells of Cajal (ICC) are important players in the symphony of gut motility. They have a very signif icant physiological role orchestrating the normal peristaltic activity of the digestive system. They are the pacemaker cells in gastrointestinal (GI) muscles. Absence, reduction in number or altered integrity of the ICC network may have a dramatic effect on GI system motility. More understanding of ICC physiology will foster advances in physiology of gut motility which will help in a future breakthrough in the pharmacological interventions to restore normal motor function of GI tract. This mini review describes what is known about the physiologic function and role of ICCs in GI system motility and in a variety of GI system motility disorders.
文摘Achalasia cardia is one of the common causes of motor dysphagia.Though the disease was first described more than 300 years ago,exact pathogenesis of this condition still remains enigmatic.Pathophysiologically,achalasia cardia is caused by loss of inhibitory ganglion in the myenteric plexus of the esophagus.In the initial stage,degeneration of inhibitory nerves in the esophagus results in unopposed action of excitatory neurotransmitters such as acetylcholine,resulting in high amplitude non-peristaltic contractions(vigorous achalasia);progressive loss of cholinergic neurons over time results in dilation and low amplitude simultaneous contractions in the esophageal body(classic achalasia).Since the initial description,several studies have attempted to explore initiating agents that may cause the disease,such as viral infection,other environmental factors,autoimmunity,and genetic factors.Though Chagas disease,which mimics achalasia,is caused by an infective agent,available evidence suggests that infection may not be an independent cause of primary achalasia.A genetic basis for achalasia is supported by reports showing occurrence of disease in monozygotic twins,siblings and other first-degree relatives and occurrence in association with other genetic diseases such as Down's syndrome and Parkinson's disease.Polymorphisms in genes encoding for nitric oxide synthase,receptors for vasoactive intestinal peptide,interleukin 23 and the ALADIN gene have been reported.However,studies on larger numbers of patients and controls from different ethnic groups are needed before definite conclusions can be obtained.Currently,the disease is believed to be multi-factorial,with autoimmune mechanisms triggered by infection in a genetically predisposed individual leading to degeneration of inhibitory ganglia in the wall of the esophagus.
基金Supported by The Fund of Scientific Research(FWO),Flanders, Project G.0134.07the University of Antwerp,BOF Grant FA02/3/3257
文摘AIM:To investigate the therapeutic effect of Schistosoma mansoni(S.mansoni) soluble worm proteins on gastrointestinal motility disturbances during experimental colitis in mice. METHODS:Colitis was induced by intrarectal injection of trinitrobenzene sulphate(TNBS) and 6 h later,mice were treated ip with S.mansoni proteins.Experiments were performed 5 d after TNBS injection.Inflammationwas quantified using validated inflammation parameters. Gastric emptying and geometric center were measured to assess in vivo gastrointestinal motility.Peristaltic activity of distal colonic segments was studied in vitro using a modified Trendelenburg set-up.Cytokine profiles of T-lymphocytes isolated from the colon were determined by real time reverse transcriptase-polymerase chain reaction. RESULTS:Intracolonic injection of TNBS caused severe colitis.Treatment with S.mansoni proteins significantly ameliorated colonic inflammation after 5 d.TNBS did not affect gastric emptying but significantly decreased the geometric center and impaired colonic peristaltic activity 5 d after the induction of colitis.Treatment with S.mansoni proteins ameliorated these in vivo and in vitro motility disturbances.In addition,TNBS injection caused a downregulation of effector T cell cytokines after 5 d,whereas a S.mansoni protein effect was no longer observed at this time point. CONCLUSION:Treatment with S.mansoni proteins attenuated intestinal inflammation and ameliorated motility disturbances during murine experimental colitis.
文摘AIM: To demonstrate the optimal surgical procedure for gastroesophageal reflux disease. METHODS: The electronic databases of Medline, Elsevier, Springerlink and Embase over the last 16 years were searched. All clinical trials involved in the outcomes of laparoscopic Nissen fundoplication (LNF) and laparoscopic Toupet fundoplication (LTF) were identified. The data of assessment in benefits and adverse results of LNF and LTF were extracted and compared using metaanalysis. RESULTS: We ultimately identified a total of 32 references reporting nine randomized controlled trials, eight prospective cohort trials and 15 retrospective trials. These studies reported a total of 6236 patients, of whom 4252 (68.18%) underwent LNF and 1984 (31.82%) underwent LTF. There were no differences between LNF and LTF in patients' satisfaction, perioperative complications, postoperative heartburn, refluxrecurrence and reoperation. Both LNF and LTF enhanced the function of lower esophageal sphincter and improved esophagitis. The postoperative dysphagia, gasbloating syndrome, inability to belch and the need for dilatation after LNF were more common than after LTF. Subgroup analyses showed that dysphagia after LNF and LTF was similar in patients with normal esophageal peristalsis (EP), but occurred more frequently in patients with weak EP after LNF than after LTF. Furthermore, patients with normal EP after LNF still had a higher risk of developing dysphagia than did patients with abnormal EP after LTF.CONCLUSION: Compared with LNF, LTF offers equivalent symptom relief and reduces adverse results.
文摘In order to relieve the abdominal distension and other discomforts due to gastrointestinal dysfunction after abdominal operations, the patients were treated by auricular-plaster therapy plus acupuncture at Zusanli (ST 36). 12 (92.4%) of the 13 cases in the treatment group showed recovery of normal peristalsis within 72 hours after operations, while that in 13 cases of the control group was 46.1%, indicating that auricular-plaster therapy plus acupuncture at Zusanli (ST 36) may promote postoperative recovery of the intestinal function.
基金Supported by Det Obelske Familiefond and Spar Nord Fonden
文摘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.
文摘＂ Analysis is performed to study the slip effects on the peristaltic flow of non-Newtonian fluid in a curved channel with wall properties. The resulting nonlinear partial differential equations are transformed to a single ordinary differential equation in a stream function by using the assumptions of long wavelength and low Reynolds number. This differential equation is solved numerically by employing the built-in routine for solving nonlinear boundary value problems （BVPs） through the software Mathematica. In addition, the analytic solutions for small Deborah number are computed with a regular perturbation technique. It is noticed that the symmetry of bolus is destroyed in a curved channel. An intensification in the slip effect results in a larger magnitude of axial velocity. Further, the size and circulation of the trapped boluses increase with an increase in the slip parameter. Different from the case of planar channel, the axial velocity profiles are tilted towards the lower part of the channel. A comparative study between analytic and numerical solutions shows excellent agreement.
文摘Investigation concerning peristaltic motion of couple stress fluid is made. An incompressible couple stress fluid occupies the porous medium. Mathematical anal- ysis is presented through large wavelength and low Reynolds number. Exact analytical expressions of axial velocity, volume flow rate, pressure gradient, and stream function are calculated as a function of couple stress parameter. The essential feature of the analysis is a full description of influence of couple stress parameter and permeability parameter on the pressure, frictional force, mechanical efficiency, and trapping.
文摘The peristaltic transport of a magnetohydrodynamic （MHD） fluid is exam- ined for both symmetric and asymmetric channels. Hall and ion slip effects are taken into account. The heat transfer is analyzed by considering the effects of viscous and Ohmic dissipations. The relevant flow problems are first modeled, and then the closed form solutions are constructed under the assumptions of long wavelength and low Reynolds number. The solutions are analyzed through graphical illustration. It is noted that the velocity increases but the temperature decreases with the increases in the Hall and ion slip parameters. The axial pressure gradient is less in magnitude in the presence of Hall and ion slip currents. The Hall and ion slip effects are to decrease the maximum pres- sure against which peristalsis works as a pump. The free pumping flux decreases with the increases in the Hall and ion slip parameters. The increases in the Hall and ion slip parameters result in an increase in the size of the trapped bolus.
文摘In this investigation,we have studied the peristaltic fluid flow in an asymmetric channel with convective walls.Fourth grade fluid model has been utilized in view of the fact that the results of all other differential type models can be deduced as the special case.Combined effects of heat and mass transfer are considered.The thermophoresis effects occur in the energy equation.Convective heat and mass boundary conditions have been given special attention.Long wave length and low Reynolds number approximations are utilized for the simplifications.Approximate analytic solutions for the velocity,temperature and concentration profiles are calculated using perturbation technique and elaborated in the form of graphical observations for various physical quantities.
