How to diagnose GERC more effectively: reflections on post-reflux swallow-induced peristaltic wave index and mean nocturnal baseline impedance.

INTRODUCTION: Post-reflux swallow-induced peristaltic wave index (PSPWI) and mean nocturnal baseline impedance (MNBI) are novel parameters reflect esophageal clearance capacity and mucosal integrity. They hold potential in aiding the recognition of gastroesophageal reflux-induced chronic cough (GERC). Our study aims to investigate their diagnostic value in GERC. METHODS: This study included patients suspected GERC. General information and relevant laboratory examinations were collected, and final diagnosis were determined following guidelines for chronic cough. The parameters of multichannel intraluminal impedance-pH monitoring (MII-pH) in patients were analyzed and compared to explore their diagnostic value in GERC. RESULTS: A total of 186 patients were enrolled in this study. The diagnostic value of PSPWI for GERC was significant, with the area under the working curve (AUC) of 0.757 and a cutoff value of 39.4%, which was not statistically different from that of acid exposure time (AET) (p > 0.05). The combined diagnostic value of AET > 4.4% and PSPWI < 39.4% was superior to using AET > 4.4% alone (p < 0.05). Additionally, MNBI and distal MNBI also contributed to the diagnosis of GERC, with AUC values of 0.639 and 0.624, respectively. AET > 4.4% or PSPWI < 39.4% is associated with a 44% reduction in missed diagnoses of non-acid GERC compared to AET > 6.0% or symptom association probability (SAP) ≥ 95%, and may be more favorable for identifying GERC. CONCLUSION: The diagnostic value of PSPWI for GERC is comparable to that of AET. Combining PSPWI < 39.4% or AET > 4.4% can improve the diagnostic efficiency by reducing the risk of missed diagnoses in cases where non-acid reflux is predominant. Distal MNBI and MNBI can serve as secondary reference indices in the diagnosis of GERC.

Mixed uncertainty analysis on pumping by peristaltic hearts using Dempster-Shafer theory.

In this paper, we introduce the numerical strategy for mixed uncertainty propagation based on probability and Dempster-Shafer theories, and apply it to the computational model of peristalsis in a heart-pumping system. Specifically, the stochastic uncertainty in the system is represented with random variables while epistemic uncertainty is represented using non-probabilistic uncertain variables with belief functions. The mixed uncertainty is propagated through the system, resulting in the uncertainty in the chosen quantities of interest (QoI, such as flow volume, cost of transport and work). With the introduced numerical method, the uncertainty in the statistics of QoIs will be represented using belief functions. With three representative probability distributions consistent with the belief structure, global sensitivity analysis has also been implemented to identify important uncertain factors and the results have been compared between different peristalsis models. To reduce the computational cost, physics constrained generalized polynomial chaos method is adopted to construct cheaper surrogates as approximations for the full simulation.

Saline volume required to achieve peristaltic intraluminal pressure during leak testing of canine colotomies, using two methods of luminal occlusion.

Background: No studies have appeared in the literature evaluating the intraluminal volume of injected saline in the canine colon for performing leak tests in colotomy incisions. Aim: To determine the volume of the injected intraluminal saline necessary to achieve an intraluminal pressure of 17.3 cm H2O in 10 cm colonic segments containing a closed colotomy occluded with intestinal forceps or by digital pressure. Methods: Fresh colon was obtained from 8 canine cadavers and divided into 10 cm segments. A 3 cm antimesenteric colonic incision was performed at each intestinal segment which was closed using a 3-0 polydioxanone suture in a simple continuous pattern. Each colonic construct was occluded with Doyen intestinal forceps or by digital pressure and a leak test was performed by saline infusion. The saline volume needed to achieve a predetermined intraluminal pressure of 17.3 cm H2O, following occlusion was recorded. Results: The mean volume of injected saline with the Doyen intestinal forceps occlusion (20.4 ± 8.2 ml) was significantly larger than that of the digital occlusion technique (17.5 ± 6.8 ml) [p = 0.021]. Conclusion: For 10 cm canine colonic constructs containing a closed colotomy, saline volumes of 20.4 ml with Doyen occlusion and 17.5 ml with digital occlusion can be utilized to achieve intraluminal pressures of 17.3 cm H2O.

Discriminating "impaired" from "disordered" contractile response on FLIP panometry by utilizing pressure measurement.

BACKGROUND: Functional lumen imaging probe (FLIP) panometry evaluates esophageal motility, including the contractile response to distension, that is, secondary peristalsis. Impaired/disordered contractile response (IDCR) is an abnormal, but nonspecific contractile response that can represent either hypomotility or spastic motor disorders on high-resolution manometry (HRM). We hypothesized that FLIP pressure could be incorporated to clarify IDCR and aimed to determine its utility in a cohort of symptomatic esophageal motility patients. METHODS: 173 adult patients that had IDCR on FLIP panometry and HRM with a conclusive Chicago Classification v4.0 (CCv4.0) diagnosis were included and analyzed as development (n = 118) and validation (n = 55) cohorts. FLIP pressure values were assessed for prediction of either hypomotility or spasm, defined on HRM/CCv4.0. KEY RESULTS: HRM/CCv4.0 diagnoses were normal motility in 48 patients (28%), "hypomotility" (ineffective esophageal motility, absent contractility, or Type I or II achalasia) in 89 (51%), and "spasm" (Type III achalasia, distal esophageal spasm, or hypercontractile esophagus) in 36 (21%). The pressure at esophagogastric junction-distensibility index (DI) (60 mL) was lower in hypomotility (median [interquartile range] 34 [28-42] mmHg) than in spasm (49 [40-62] mmHg; p < 0.001) and had an area under the receiver operating characteristic curve of 0.80 (95% CI 0.73-0.88) for hypomotility and 0.76 (0.69-0.83) for spasm. For "spasm" on HRM, a threshold FLIP pressure of >35 mmHg provided 90% sensitivity (47% specificity) while >55 mmHg provided 93% specificity (40% sensitivity). CONCLUSION & INFERENCES: Pressure on FLIP panometry can help clarify the significance of IDCR, with low-pressure IDCR associated with hypomotility and high-pressure IDCR suggestive of spastic motor disorders.

Nanoparticle aggregation and electro-osmotic propulsion in peristaltic transport of third-grade nanofluids through porous tube.

In the modern era, the utilization of electro-kinetic-driven microfluidic pumping procedures spans various biomedical and physiological domains. The present study introduces a mathematical framework for characterizing the hemodynamics of peristaltic blood flow within a porous tube infused with ZrO2 nanoparticles. This model delves into the interactions between buoyancy, electro-osmotic forces, and aggregated nanoparticles to discern their influence on blood flow. We employ a third-grade fluid model to elucidate the rheological behavior of the pseudoplastic fluid which refers to its response to applied shear stress, specifically the relationship between shear rate and viscosity. The collective influence of accommodating heat convection, joule heating and aggregated nanoparticles contributes to the thermal behavior of fluids. The distribution of electric potential within the electric double layer (EDL) is predicted by solving the Poisson-Boltzmann equation. The rescaled equations are simplified using the lubrication and Debye-Hückel models as the underlying frameworks. The novel homotopy perturbation method is employed to obtain solutions for the finalized non-linear partial differential equation. Theoretical assessment of hemodynamic impacts involves plotting graphical configurations for various emerging parameters. As electro-osmotic parameter increase, the bloodstream encounters greater impedance, thereby enhancing the effectiveness of electro-osmotic assistance. Concurrently, elevated convective heat markedly reduces the rate of heat transfer, potentially resulting in a drop in blood temperature. It is important to note that maximum shear stress occurs when the artery is positioned horizontally, underscoring the significant impact of arterial alignment on wall shear stress. Skin friction intensifies with the increasing wall permeability as aggregated nanofluids pass through the arterial conduit. Therefore, aggregation of nanoparticles into the bloodstream yields a broader spectrum of distinctive physiological features. In summary, these findings enable more effective tool and device designs for addressing medication administration challenges and electro-therapies.

A fluorescently-tagged tick kinin neuropeptide triggers peristalsis and labels tick midgut muscles.

Ticks are blood-feeding arthropods that require heme for their successful reproduction. During feeding they also acquire pathogens that are subsequently transmitted to humans, wildlife and/or livestock. Understanding the regulation of tick midgut is important for blood meal digestion, heme and nutrient absorption processes and for aspects of pathogen biology in the host. We previously demonstrated the activity of tick kinins on the cognate G protein-coupled receptor. Herein we uncovered the physiological role of the kinin receptor in the tick midgut. A fluorescently-labeled kinin peptide with the endogenous kinin 8 sequence (TMR-RK8), identical in the ticks Rhipicephalus microplus and R. sanguineus, activated and labeled the recombinant R. microplus receptor expressed in CHO-K1 cells. When applied to the live midgut the TMR-RK8 labeled the kinin receptor in muscles while the labeled peptide with the scrambled-sequence of kinin 8 (TMR-Scrambled) did not. The unlabeled kinin 8 peptide competed TMR-RK8, decreasing confocal microscopy signal intensity, indicating TMR-RK8 specificity to muscles. TMR-RK8 was active, inducing significant midgut peristalsis that was video-recorded and evaluated with video tracking software. The TMR-Scrambled peptide used as a negative control did not elicit peristalsis. The myotropic function of kinins in eliciting tick midgut peristalsis was established.

Relationship between endoscopic gastroesophageal valve grading and mean nocturnal baseline impedance and postreflux swallow-induced peristaltic wave index in patients with gastroesophageal reflux disease.

This study aimed to investigate the relationship between endoscopic gastroesophageal valve grading and mean nocturnal baseline impedance (MNBI) and postreflux swallow-induced peristaltic wave index (PSPWI) in patients with gastroesophageal reflux disease (GERD). A total of 120 patients diagnosed with GERD disease were included in the study. According to the classification of endoscopic gastroesophageal valves, the patients were divided into 5 groups, group 1 as baseline group, and Group 2-4 as Hill grade I-IV. Basic information about the patients was collected, including age and gender. The mean nocturnal baseline impedance and creep wave index induced by swallowing after rumination were measured by high resolution creep measurement technique. Through statistical analysis, the relationship between valve classification and observation index was discussed. In terms of MNBI, impedance values gradually decreased with increasing valve classification. The average impedance of the Grade 1 group was 23.5 mm Hg/cm2, while the average impedance of the Grade 5 group was 15.2 mm Hg/cm2. This reduction showed a significant decreasing trend (P < .001). In addition, in terms of the peristaltic wave index caused by swallowing after regurgitation, the peristaltic wave index gradually increased with the increase of valve classification. The mean index in the Grade 1 group was 1.8 beats/min, while the mean index in the Grade 5 group was 3.6 beats/min. This increase showed a significant positive relationship (P < .001). Endoscopic gastroesophageal valve grading was significantly correlated with MNBI and PSPWI in patients with GERD. These observations can serve as useful tools for assessing the severity of GERD and monitoring disease progression.

Biomechanical increase in cervical esophageal wall tension during peristalsis.

During pharyngeal phase of swallowing, circumferential tension of the cervical esophagus (CTE) increases caused by a biomechanical process of laryngeal elevation pulling the cervical esophagus orad. The esophagus contracts longitudinally during esophageal peristalsis, therefore, we hypothesized that CTE increases during esophageal peristalsis by a biomechanical process. We investigated this hypothesis using 28 decerebrate cats instrumented with electromyographic (EMG) electrodes on the pharynx and esophagus, and esophageal manometry. We recorded CTE, distal esophageal longitudinal tension (DET), and orad laryngeal tension (OLT) using strain gauges. Peristalsis was stimulated by injecting saline into esophagus or nasopharynx. We investigated the effects of transecting the pharyngo-esophageal nerve (PEN), hypoglossal nerve (HG), or administering (10 mg/kg iv) hexamethonium (HEX). We found that the durations of CTE and DET increased and OLT decreased simultaneously during the total extent of esophageal peristalsis. CTE duration was highly correlated with DET but not esophageal EMG or manometry. The peak magnitudes of the DET and CTE were highly correlated. After HEX administration, peristalsis in the distal esophagus did not occur, and the duration of the CTE response decreased. PEN transection blocked the occurrence of cricopharyngeal or cervical esophageal response during peristalsis but had no significant effect on the CTE response. HG transection had no significant effect on CTE. We conclude that there is a significant CTE increase, independent of laryngeal elevation or esophageal muscle contraction, which occurs during esophageal peristalsis. This response is a biomechanical process caused by esophageal shortening that occurs during esophageal longitudinal contraction of esophageal peristalsis.NEW & NOTEWORTHY Circumferential tension of cervical esophagus (CTE) increases during esophageal peristalsis. CTE response is correlated with distal longitudinal tension on cervical esophagus during esophageal peristalsis but not laryngeal elevation or esophageal muscle contraction. CTE response is not blocked by transection of motor innervation of laryngeal elevating muscles or proximal esophagus but is temporally reduced after hexamethonium administration. We conclude that the CTE response is a biomechanical effect caused by longitudinal esophageal contraction during esophageal peristalsis.

Megacystis microcolon intestinal hypoperistalsis syndrome (MMIHS): challenges in diagnosis and management.

Megacystis microcolon intestinal hypoperistalsis syndrome (MMIHS) is a rare, congenital functional intestinal obstruction, characterised by megacystis (bladder distention in the absence of mechanical obstruction), microcolon and intestinal hypoperistalsis (dysmotility).We are reporting a case of a female child with normal antenatal course who presented with recurrent episodes of abdominal distension since the second day of life and underwent negative exploratory laparotomy on multiple occasions. She also had urinary retention with a grossly distended bladder, requiring drainage by clean intermittent catheterisation. Surgical procedures for bowel decompression, including gastrostomy and ileostomy, were carried out without success. Genetic analysis revealed a mutation in the human smooth muscle (enteric) gamma-actin gene (ACTG2 gene), clinching the diagnosis of MMIHS. The patient was managed with parenteral nutrition and prokinetic medications and tolerated jejunostomy feeds for a brief period before she succumbed to the illness.Female neonates or infants presenting with abdominal distension and dilated urinary tract should be investigated for MMIHS early on. A timely diagnosis will enable the early involvement of a multidisciplinary team to provide the best options available for management.

Saliva Production and Esophageal Motility Influence Esophageal Acid Clearance Related to Post-reflux Swallow-Induced Peristaltic Wave.

BACKGROUND: The post-reflux swallow-induced peristaltic wave (PSPW) brings salivary bicarbonate to neutralize residual distal esophageal mucosal acidification. AIMS: To determine if reduced saliva production and esophageal body hypomotility would compromise PSPW-induced pH recovery in the distal esophagus. METHODS: In this multicenter retrospective cross-sectional study, patients with confirmed Sjogren's syndrome and scleroderma/mixed connective tissue disease (MCTD) who underwent high resolution manometry (HRM) and ambulatory pH-impedance monitoring off antisecretory therapy were retrospectively identified. Patients without these disorders undergoing HRM and pH-impedance monitoring for GERD symptoms were identified from the same time-period. Acid exposure time, numbers of reflux episodes and PSPW, pH recovery with PSPW, and HRM metrics were extracted. Univariate comparisons and multivariable analysis were performed to determine predictors of pH recovery with PSPW. RESULTS: Among Sjogren's syndrome (n = 34), scleroderma/MCTD (n = 14), and comparison patients with reflux symptoms (n = 96), the scleroderma/MCTD group had significantly higher AET, higher prevalence of hypomotility, lower detected reflux episodes, and very low numbers of PSPW (p ≤ 0.004 compared to other groups). There was no difference in pH-impedance metrics between Sjogren's syndrome, and comparison patients (p ≥ 0.481). Proportions with complete pH recovery with PSPW was lower in Sjogren's patients compared to comparison reflux patients (p = 0.009), predominantly in subsets with hypomotility (p < 0.001). On multivariable analysis, diagnosis of Sjogren's syndrome, scleroderma/MCTD or neither (p = 0.014) and esophageal hypomotility (p = 0.024) independently predicted lack of complete pH recovery with PSPW, while higher total reflux episodes trended (p = 0.051). CONCLUSIONS: Saliva production and motor function are both important in PSPW related pH recovery.

Resistance model of an active capsule endoscope in a peristaltic intestine.

In the past studies, the resistance of magnetically controlled capsules running through the small intestine has been modeled assuming that the small intestine was a circular tube with a constant diameter. Peristalsis is an important character of the human gastrointestinal system, and it would result in some changes in the diameter of the intestine, meaning that the existing resistance models would no longer be applicable. In this paper, based on the assumption that intestinal peristalsis is actually a sinusoidal wave, a resistance model of the capsule running in the peristaltic intestine is established, and then it is validated experimentally. The model provides a realistic foundation for the optimization and control of the magnetically controlled endoscopy.

An analytical and comparative study of swallowing in a tumor-infected oesophagus: a mathematical model.

This study discusses non-steady effects encountered in peristaltic flows in oesophagus. The purpose of this communication is to evolve a mechanism to diagnose tumor in an oesophagus mathematically. The tumor is modelled by generic bump function of certain height and width. The method of solution follows long wavelength and low-Reynolds number approximations for unsteady flow, while integrations have been performed numerically in order to plot graphs, which reveal various characteristics of the flow. The goal is to assess how pressure varies across the tumor's width. The spatial, as well as temporal, dependence of pressure has been studied in the laboratory frame of reference. The pressure distribution for tumor-infected oesophagus is compared with that of normal oesophagus. An intensified pressure is obtained in the presence of tumor. The interruption while swallowing through benign oesophageal tumor is confirmed by an abrupt pressure rise across the tumor's width. Tumor position also plays a significant role whether it is at contraction or relaxation of walls. Additionally, wall-shear-stress, volumetric flow rate and streamlines have also been described and compared with that without tumor growth. The expressions corresponding to all the physical quantities are computed numerically. Further, this model may also be implemented to the two-dimensional channel flow for an industrial application.

Efficacy of Glycicumarin and Isoliquiritigenin in Suppressing Colonic Peristalsis in Both an Animal Model and a Clinical Trial.

Patients with diarrhea-predominant irritable bowel syndrome (IBS-D) show excessive peristalsis, and antispasmodic agents may be useful therapeutic agents. There are few reports on the use of Kampo medicines for the treatment of IBS-D. Shakuyakukanzoto (SKT) is a Kampo medicine that is effective against abdominal pain. We examined the relationship between SKT and intestinal peristalsis in an animal model and a prospective study. In the animal model, SKT and its components were administered from the serosal side of the colon and colonic peristalsis was evaluated using intraluminal pressure and spatiotemporal mapping before and after the administration of SKT and its components. In this clinical trial, we used abdominal ultrasonography (US) to obtain long-axis images of the sigmoid colon of 11 patients. The frequency of intestinal peristalsis was measured using US in five patients with SKT and six patients without medication after the ingestion of a test meal. The primary outcome was the frequency of peristalsis. The Clinical Trial Registry Website (Trial No. UMIN-CTR; UMIN000051547). In the animal model, peony did not suppress peristalsis frequency, but SKT (p = 0.005) and glycyrrhiza (p = 0.001) significantly suppressed peristalsis frequency compared with saline and peony. Among the glycyrrhiza components, glycycoumarin and isoliquiritigenin suppressed the peristalsis frequency compared to dimethyl sulfoxide (control) (p = 0.001, 0.01, respectively). In a clinical trial, peristalsis was significantly suppressed after oral administration in patients taking SKT (p = 0.03). Administration of SKT was found to inhibit colonic peristalsis, with glycicumarin and isoliquiritigenin being particularly relevant among its components.

Pain-free oral delivery of biologic drugs using intestinal peristalsis-actuated microneedle robots.

Biologic drugs hold immense promise for medical treatments, but their oral delivery remains a daunting challenge due to the harsh digestive environment and restricted gastrointestinal absorption. Here, inspired by the porcupinefish's ability to inflate itself and deploy its spines for defense, we proposed an intestinal microneedle robot designed to absorb intestinal fluids for rapid inflation and inject drug-loaded microneedles into the insensate intestinal wall for drug delivery. Upon reaching the equilibrium volume, the microneedle robot leverages rhythmic peristaltic contraction for mucosa penetration. The robot's barbed microneedles can then detach from its body during peristaltic relaxation and retain in the mucosa for drug releasing. Extensive in vivo experiments involving 14 minipigs confirmed the effectiveness of the intestinal peristalsis for microrobot actuation and demonstrated comparable insulin delivery efficacy to subcutaneous injection. The ingestible peristalsis-actuated microneedle robots may transform the oral administration of biologic drugs that primary relies on parenteral injection currently.

CFD investigation of multiple peristaltic waves in a 3D unobstructed ureter.

Ureters are essential components of the urinary system and play a crucial role in the transportation of urine from the kidneys to the bladder. In the current study, a three-dimensional ureter is modelled. A series of peristaltic waves are made to travel on the ureter wall to analyse and measure parameter effects such as pressure, velocity, gradient pressure, and wall shear at different time steps. The flow dynamics in the ureters are thoroughly analysed using the commercially available ANSYS-CFX software. The maximum pressure is found in the triple wave at the ureteropelvic junction and maximum velocity is observed in the single and double wave motion due to the contraction produced by the peristalsis motion. The pressure gradient is maximum at the inlet of the ureter during the single bolus motion. The contraction produces a high jet of velocity due to neck formation and also helps in urine trapping in the form of a bolus, which leads to the formation of reverse flow. Due to the reduction in area, shear stress builds on the ureter wall. The high shear stress may rupture the junctions in the ureter.

Uterine peristalsis in women affected by adenomyosis: A step towards functional assessment.

OBJECTIVE: The non-pregnant uterus shows an intrinsic contractility pattern, actively involved in early reproductive processes. Uterine contractility is characterized by endometrial waves that originate from the junctional zone and varies throughout the menstrual cycle due to fluctuations in the concentrations of hormones. The aim of this study was to compare the uterine contractility patterns in the periovulatory phase in a group of patients with isolated adenomyosis and a group of healthy women using transvaginal ultrasound (TVUS). METHODS: From March 2019 to March 2021, we enrolled consecutive nulliparous patients in the periovulatory phase of the menstrual cycle, divided in patients with isolated adenomyosis (group A, n = 18) and healthy patients in the control group (group B, n = 18). Patients who met the inclusion criteria underwent TVUS for the study of uterine contractility: the uterus was scanned on sagittal plane for 3 min and all the movies were recorded. Then, static images and video were evaluated offline and the uterine contractility patterns were defined. RESULTS: The patients belonging to the study group had a higher incidence of painful symptoms (dysmenorrhea, 6.11 ± 2.81 vs 1.39 ± 2.17; chronic pelvic pain, 2.56 ± 3.01 vs 0.39 ± 1.04) and a larger uterine volume (137.48 ± 117.69 vs 74.50 ± 27.58 cm3; P = 0.04). Regarding the uterine contractility, a statistically significant difference was observed about the retrograde patterns (group A, 27.8% vs group B, 72.2%, P < 0.01) and opposing (group A, 38.9% vs, group B, 5.6%, P = 0.02). CONCLUSION: The study confirms the presence of altered uterine peristalsis in the periovulatory phase in patients with adenomyosis. The abnormal uterine peristalsis could lead to both structural and functional changes, which are the basis of the clinical manifestations of adenomyosis and the perpetuation of the anatomical damage.

Secondary peristalsis and esophagogastric junction distensibility in symptomatic post-fundoplication patients.

BACKGROUND: The impact of esophageal dysmotility among patients with post-fundoplication esophageal symptoms is not fully understood. This study aimed to investigate secondary peristalsis and esophagogastric junction (EGJ) opening biomechanics using functional lumen imaging probe (FLIP) panometry in symptomatic post-fundoplication patients. METHODS: Eighty-seven adult patients post-fundoplication who completed FLIP for symptomatic esophageal evaluation were included. Secondary peristaltic contractile response (CR) patterns and EGJ opening metrics (EGJ distensibility index (EGJ-DI) and maximum EGJ diameter) were evaluated on FLIP panometry and analyzed against high-resolution manometry (HRM), patient-reported outcomes, and fundoplication condition seen on esophagram and/or endoscopy. KEY RESULTS: FLIP CR patterns included 14 (16%) normal CR, 30 (34%) borderline CR, 28 (32%) impaired/disordered CR, 13 (15%) absent CR, and 2 (2%) spastic reactive CR. Compared with normal and borderline CRs (i.e., CR patterns with distinct, antegrade peristalsis), patients with impaired/disordered and absent CRs demonstrated significantly greater time since fundoplication (2.4 (0.6-6.8) vs. 8.9 (2.6-14.5) years; p = 0.002), greater esophageal body width on esophagram (n = 50; 2.3 (2.0-2.8) vs. 2.9 (2.4-3.6) cm; p = 0.013), and lower EGJ-DI (4.3 (2.7-5.4) vs. 2.6 (1.7-3.7) mm2/mmHg; p = 0.001). Intact fundoplications had significantly higher rates of normal CRs compared to anatomically abnormal (i.e., tight, disrupted, slipped, herniated) fundoplications (9 (28%) vs. 5 (9%); p = 0.032), but there were no differences in EGJ-DI or EGJ maximum diameter. CONCLUSIONS & INFERENCES: Symptomatic post-fundoplication patients were characterized by frequent abnormal secondary peristalsis after fundoplication, potentially worsening with time after fundoplication or related to EGJ outflow resistance.

[A Case of Type II Achalasia Occurring in a Nonagenarian Diagnosed with Acute Food Impaction].

Achalasia is an esophageal motility disorder characterized by loss of esophageal peristalsis and impaired relaxation of the lower esophageal sphincter. Patients with achalasia often complain of persistent symptoms for several years before diagnosis. On the other hand, achalasia diagnosed as a sudden esophageal food impaction is uncommon, and no report has been issued on the diagnosis and successful treatment of achalasia in a 95-year-old patient. We report a case of achalasia diagnosed by high-resolution esophageal manometry and timed barium esophagography after food material removal by endoscopy in a 95-year-old woman who visited the hospital due to sudden esophageal food impaction and was successfully treated by endoscopic balloon dilatation.

Peristalsis prevents ureteral dilation.

PURPOSE: The etiology of ureteral dilation in primary nonrefluxing, nonobstructing megaureters is still not well understood. Impaired ureteral peristalsis has been theorized as one of the contributing factors. However, ureteral peristalsis and its "normal" function is not well defined. In this study, using mathematical modeling techniques, we aim to better understand how ureteral peristalsis works. This is the first model to consider clinically observed, back-and-forth, cyclic wall longitudinal motion during peristalsis. We hypothesize that dysfunctional ureteral peristalsis, caused by insufficient peristaltic amplitudes (e.g., circular muscle dysfunction) and/or lack of ureteral wall longitudinal motion (e.g., longitudinal muscle dysfunction), promotes peristaltic reflux (i.e., retrograde flow of urine during an episode of peristalsis) and may result in urinary stasis, urine accumulation, and consequent dilation. METHODS: Based on lubrication theory in fluid mechanics, we developed a two-dimensional (planar) model of ureteral peristalsis. In doing so, we treated ureteral peristalsis as an infinite train of sinusoidal waves. We then analyzed antegrade and retrograde flows in the ureter under different bladder-kidney differential pressure and peristalsis conditions. RESULTS: There is a minimum peristaltic amplitude required to prevent peristaltic reflux. Ureteral wall longitudinal motion decreases this minimum required amplitude, increasing the nonrefluxing range of peristaltic amplitudes. As an example, for a normal bladder-kidney differential pressure of 5 cmH2 O, ureteral wall longitudinal motion increases nonrefluxing range of peristaltic amplitude by 65%. Additionally, ureteral wall longitudinal motion decreases refluxing volumetric flow rates. For a similar normal bladder pressure example of 5 cmH2 O, refluxing volumetric flow rate decreases by a factor of 18. Finally, elevated bladder pressure, not only increases the required peristaltic amplitude for reflux prevention but it increases maximum refluxing volumetric flow rates. For the case without wall longitudinal motion, as bladder-kidney differential pressure increases from 5 to 40 cmH2 O, minimum required peristaltic amplitude to prevent reflux increases by 40% while the maximum refluxing volumetric flow rate increases by approximately 100%. CONCLUSION: The results presented in this study show how abnormal ureteral peristalsis, caused by the absence of wall longitudinal motion and/or lack of sufficient peristaltic amplitudes, facilitates peristaltic reflux and retrograde flow. We theorize that this retrograde flow can lead to urinary stasis and urine accumulation in the ureters, resulting in ureteral dilation seen on imaging studies and elevated infection risk. Our results also show how chronically elevated bladder pressures are more susceptible to such refluxing conditions that could lead to ureteral dilation.