Tolerable Volume Research Articles

Improvement of Patient Satisfaction and Anorectal Manometry Parameters After Biofeedback Therapy in Patients with Different Types of Dyssynergic Defecation.

Biofeedback is a well-known and effective treatment for patients with fecal evacuation disorder (FED). The main purpose of this study was to investigate the outcome and the effects of biofeedback therapy on physiological parameters as assessed by manometry in patients with FED. Data from 114 consecutive patients with FED who underwent biofeedback therapy in Sara Gastrointestinal clinic in Tehran, Iran during 2015-2018 were retrospectively reviewed and analyzed. All participants underwent a comprehensive evaluation of anorectal function that included anorectal manometry and a balloon expulsion test at the baseline and after biofeedback therapy. Maximum anal squeeze pressure and sustained anal squeeze pressure were improved up to 100% and 94.7% of normal values in the patients after biofeedback, respectively (P < 0.001). First rectal sensation, was significantly decreased (25 ± 18.5 vs. 15.5 ± 5.2) while the maximum tolerable volume was significantly increased (233.6 ± 89.7 vs. 182.4 ± 23.1) after biofeedback therapy (P < 0.001). Type I dyssynergia was the most common type, effecting 82 cases (71.9%) of our patients. Dyssynergia parameters were improved 50-80% in 34 (41.5%) and 10 (31.3%) type I and non-type I patients, respectively. Over 80% improvement of dyssynergia parameters occurred in 48 (58.5%) and 22 (68.8%) type I and non-type I patients, respectively. These differences were not statistically significant between the two groups (P = 0.3). In addition, the ability to reject the balloon was significantly better in post intervention measurements (P < 0.001). Biofeedback not only improves the symptoms in patients of FED but also reverses more than 80% the dyssynergic parameters of defecation. However, due to the general effectiveness of biofeedback treatment in different types of DD, there were no significant differences between their improvement scores.

Randomised clinical trial: linaclotide vs placebo—a study of bi‐directional gut and brain axis

SummaryBackgroundLinaclotide, a guanylate cyclase C agonist relieves irritable bowel syndrome with predominant constipation (IBS‐C) symptoms, but how it improves pain in humans is unknown.AimsTo investigate the effects of linaclotide and placebo on the afferent and efferent gut‐brain‐gut signalling in IBS‐C patients, in a randomised clinical trial.MethodsPatients with IBS‐C (Rome III) and rectal hypersensitivity were randomised (2:1) to receive linaclotide (290 µg) or placebo for 10 weeks and undergo bi‐directional gut and brain axis assessment using anorectal electrical stimulations and transcranial/transspinal‐anorectal magnetic stimulations. Rectal sensations were examined by balloon distention. Assessments included abdominal pain, bowel symptoms and quality of life (QOL) scores. Primary outcomes were latencies of recto‐cortical and cortico‐rectal evoked potentials.ResultsThirty‐nine patients participated; 26 received linaclotide and 13 received placebo. Rectal cortical evoked potentials latencies (milliseconds) were significantly prolonged with linaclotide compared to baseline (P1:Δ 19 ± 6, P < 0.005; N1:Δ 20 ± 7, P < 0.02) but not with placebo (P1:Δ 3 ± 5; N1:Δ 4.7 ± 5,P = 0.3) or between groups. The efferent cortico‐anorectal and spino‐anorectal latencies were unchanged. The maximum tolerable rectal volume (cc) increased significantly with linaclotide compared to baseline (P < 0.001) and placebo (Δ 29 ± 10 vs 4 ± 20, (P < 0.03). Abdominal pain decreased (P < 0.001) with linaclotide but not between groups. Complete spontaneous bowel movement frequency increased (P < 0.001), and IBS‐QOL scores improved (P = 0.01) with linaclotide compared to baseline and placebo. There was no difference in overall responders between linaclotide and placebo (54% vs 23%, P = 0.13).ConclusionsLinaclotide prolongs afferent gut‐brain signalling from baseline but both afferent and efferent signalling were unaffected compared to placebo. Linaclotide significantly improves rectal hypersensitivity, IBS‐C symptoms and QOL compared to placebo. These mechanisms may explain the effects of linaclotide on pain relief in IBS‐C patients.ClinicalTrials.Gov: Registered at Clinical trials.gov no NCT02078323.

Sex Differences in the Oxidative Stress and Inflammation Response During and After Simulated Hemorrhage in Humans

IntroductionHemorrhage (i.e., massive blood loss) induces an oxidative stress and inflammatory response that can persist even following hemostasis and resuscitation. These responses can result in tissue and organ damage if therapeutic inventions are delayed. Pre‐menopausal females exhibit a survival advantage following hemorrhage compared to males of a similar age. The role of oxidative stress and inflammation on increased survival from blood loss in young females is under investigation. Examining the potential mechanisms underpinning this survival advantage following hemorrhage may facilitate the development of sex‐specific therapies. In our laboratory, we utilize lower body negative pressure (LBNP) to simulate blood loss in conscious human subjects. In this study, we hypothesized that young males would elicit a greater oxidative stress and inflammatory response compared to young females, both during and after a simulated hemorrhage via LBNP.MethodsYoung, healthy human subjects (10F; 10M) participated in a stepwise‐LBNP protocol to presyncope. Stroke volume was estimated via finger photoplethysmography as a marker of central hypovolemia (indexed to body surface area). Venous blood samples were collected at baseline, at the onset of presyncope, and 60‐min into recovery (i.e., following “resuscitation”). The oxidative stress response was assessed via measurement of circulating F2‐Isoprostanes (F2‐IsoP) using gas chromatography‐negative ion chemical ionization‐mass spectrometry. The inflammatory response was assessed via measurement of circulating interleukin (IL)‐6 and IL‐10 using a MSD® Multiplex assay. Unpaired t‐tests were used to compare LBNP tolerance and stroke volume responses between male and female subjects. Two factor (time and sex) linear mixed model analyses with repeated measures were performed for all other comparisons, followed by Holm‐corrected post‐hoc tests. All data are represented as mean ± SE.ResultsLBNP tolerance time was similar between male and female subjects (Males, 1592 ± 124 s vs. Females, 1437 ± 113 s; P=0.37), and stroke volume index decreased by a similar magnitude at presyncope (Males, −50.2 ± 6.3% vs. Females, −49.4 ± 3.2%; P = 0.87). There was no effect of time or sex on [F2‐IsoP] or on the %Δ [F2‐IsoP] during or after LBNP (P ≥ 0.12). However, male subjects exhibited a greater increase in both the %Δ [IL‐6] and %Δ [IL‐10] compared to female subjects at the 60‐min recovery time point (IL‐6: Males, 101.4 ± 138.9% vs. Females, 12.3 ± 34.0%; P = 0.06. IL‐10: Males, 71.1 ± 133.3% vs. Females, −2.2 ± 11.8%; P = 0.06).ConclusionThese data suggest that there may be a sex difference in the inflammatory response to blood loss and subsequent fluid resuscitation. Future clinical studies should continue to explore sex differences in inflammatory responses to actual blood loss, and tailor therapeutic interventions accordingly.Support or Funding InformationWilliam and Ella Owens Medical Research Foundation

Analyzing the Role of Anal Sphincter Pressure in Rectocele Formation.

PurposeConstipation is a common entity in society with various factors in the etiology. In this study, we evaluated the role of anal sphincter pressure of patients who refer to surgery clinic with complaint of constipation.MethodsSixty patients who refer to surgery clinic with complaint of constipation and were diagnosed with constipation due to Rome III criteria between July 2010 and September 2014. These patients were evaluated with defecography and were divided into 2 groups based on presence of rectocele. Both groups’ anal sphincter pressures were evaluated using anal manometry and findings were compared.ResultsThe patients with rectocele and without rectocele using defecography were inspected with anal manometry regarding resting tone pressure, squeeze pressure, maximum squeeze pressure and simulated defecation response pressure, first sensation volume, urge sensation volume, and maximum tolerable volume. Results were compared and no significant difference was found regarding groups with rectocele and without rectocele (P > 0.05).ConclusionWe have proved the hypothesis arguing that increased sphincter pressures do not play a role in the formation of rectocele by inducing an obstruction and the formation of dilation in proximal bowel, and demonstrated that the presence of rectocele is not dependent on an increase in sphincter pressures.

Surgical treatment of low anterior resection syndrome

Objective To compare functional outcomes of various rectal reconstruction after total mesorectal excision. Material and methods A prospective randomized trial included 90 patients with mid-to-low rectal carcinoma who underwent total mesorectal excision. Results There were 22 patients after J-pouch surgery, 30 patients with side-to-end anastomoses and 38 patients with end-to-end anastomoses. Eight patients (26.6%) required conversion of J-P to E-E (7 patients) and S-E (1) anastomosis for technical reasons. Postoperative morbidity was similar (13.6, 16.7 and 34.2% in J-P, S-E and E-E groups, respectively, p=0.705). Sensory threshold, earliest and constant defecation urge and maximal tolerable volume were higher for J-P surgery within 3-6-12 months after surgery. Stool frequency was significantly lower after J-P surgery compared to S-E and E-E anastomoses within 3-6-12 months. Wexner scores were 3, 5, 6 after 6 months (p 0.05). Evacuation dysfunction was observed in 59.1% with J-P, 33.3% with S-E and 21.1% with E-E anastomoses in 6 months after stoma closure. Conclusion J-pouch reconstruction demonstrates higher neorectal volume that ensures reduced stool frequency up to 12 months after stoma closure. However, technical challenges of J-pouch surgery and evacuation dysfunction restrain application of this procedure in clinical practice.

Familiarization With Airflow-Restriction Mask During Resistance Exercise: Effect on Tolerance and Total Volume.

Teodoro, CL, Gáspari, AF, Berton, R, Barbieri, JF, Silva, M, Castaño, LAA, Guimarães, P, and Moraes, AC. Familiarization with airflow-restriction mask during resistance exercise: Effect on tolerance and total volume. J Strength Cond Res 33(7): 1762-1765, 2019-This study investigated whether familiarization with the airflow-restriction mask (AIRfr) increases tolerance and avoids negative effects on performance of resistance exercise (RE). Ten resistance-trained male subjects performed a familiarization session (FAM), followed by 2 testing sessions, with the AIRfr and without airflow restriction (SHAM) in a counterbalanced and randomized cross-over design. The FAM was performed with the same number of sets, load, and level of airflow-restriction as the AIRfr experimental session. Each session consisted of 4 sets of the leg press exercise with 70% 1 repetition maximum until voluntary failure and a 90-second rest interval between sets. During the FAM, 4 of the 10 subjects expressed some intolerance to the use of airflow restriction. Total volume was lower in the FAM than in the AIRfr (p = 0.01) and the SHAM (p = 0.02), whereas no differences were observed between the AIRfr and the SHAM (p = 0.90). The first use of the AIRfr may not be well tolerated by all subjects. However, a familiarization session with the AIRfr avoids negative interferences in the total volume during RE.

Does Bilateral Deep Brain Stimulation of the Subthalamic Nucleus Modify Ano-Rectal Motility in Parkinson’s Disease? Results of a Randomized Cross-Over Study

Ano-rectal motility impairment is often observed during Parkinson's disease (PD), generating symptoms as constipation and/or incontinence with impaired quality of life. Subthalamic nuclei (STN) deep brain stimulation (DBS) improves motor symptoms of PD, but its effects on anorectal motility are unknown. This study aimed to assess the effects of STN-DBS on the anorectal motility in PD patients, in a randomized cross-over study. Sixteen PD patients with bilateral STN-DBS for at least 6 months were included. The anal resting pressure, duration and maximal amplitude of squeeze effort, recto-anal inhibitory reflex, maximal tolerable rectal volume, and anal pressure during defecation effort were measured and compared after STN-DBS was switched OFF and then ON for 2 hours, or vice-versa, in a randomized order. STN-DBS increased maximal amplitude of anal squeezing pressure (OFF: 85.7 ± 14.5 vs ON: 108.4 ± 21.0 cmH2 O; P = 0.02), with no significant difference in the duration (P = 0.10). No other significant difference was found between stimulation conditions (OFF vs ON) for anal resting pressure (OFF: 72.5 ± 8.6 cmH2 O vs ON: 71.7 ± 9.0 cmH2 O; P = 0.24), recto-anal inhibitory reflex, maximal tolerable rectal volume (OFF: 231 ± 24 mL vs ON: 241 ± 26 mL; P = 0.68), or anal pressure during defecation effort with a similar rate of ano-rectal dyssynergia (7/16 and 8/16 with and without STN-DBS, respectively). No order effect (ON-OFF vs OFF-ON) was observed. STN-DBS increased anal squeezing pressure, but did not modify anorectal dyssynergia in PD patients, This study demonstrated the involvement of STN in the voluntary control of anorectal motility in PD patients.

Oral medical assistance in dying (MAiD): informing practice to enhance utilization in Canada.

The legislation Bill C-14 legalized medical assistance in dying (MAiD) in Canada. After thorough assessments of eligibility by two clinicians, Bill C-14 allows for both intravenous-assisted death by a clinician (euthanasia) and prescription of oral medication for self-administration (assisted suicide). Nevertheless, since inception in June 2016, intravenous euthanasia is the main form of delivery of assisted death in Canada. The reasons why oral MAiD is underutilized in Canada are multifactorial. Currently, there is no consensus on either the medications or the protocols for oral administration, nor a comprehensive understanding of the potential side effects and complications associated with different regimens. The quality of evidence for optimal MAiD medications is low, so any suggested recommendations can only be informed by the global but generally anecdotal experience. The challenges for implementing oral MAiD in Canada include a need to enhance clinician comfort in prescribing oral medications as an alternative to intravenous administration. The goals for ideal oral MAiD medications are 100% effectiveness and minimal side effects, while ensuring that the needed dose is both palatable and deliverable in a tolerable oral volume. The Netherlands has the most experience worldwide and barbiturates have emerged as the most common, efficacious, and tolerable agents by patients. Based on this global experience and the over-arching goals for oral MAiD, we recommend the use of a secobarbital suspension combined with antiemetic prophylaxis.

Post-operative clinical, manometric, and defecographic findings in patients undergoing unsuccessful STARR operation for obstructed defecation

To evaluate the reason for failure of STARR (stapled transanal rectal resection) operation for obstructed defecation. A retrospective study (June 2012-December 2017) was performed using a prospectively maintained database of patients who underwent STARR operation for ODS (obstructed defecation syndrome), complaining of persisting or de novo occurrence of pelvic floor dysfunctions. Postoperative St Mark's and ODS scores were evaluated. A VAS was used to score pelvic pain. Patients' satisfaction was estimated administering the CPGAS (clinical patient grading assessment scale) questionnaire. Objective evaluation was performed by dynamic proctography and anorectal manometry. Ninety patients (83.3% females) operated for ODS using STARR technique were evaluated. Median ODS score was 19 while 20 patients (22%) reported de novo fecal urgency and 4 patients a worsening of their preoperative fecal incontinence. Dynamic proctography performed in 54/90 patients showed a significant (> 3.0cm) rectocele in 19 patients, recto-rectal intussusception in 10 patients incomplete emptying in 24 patients. When compared with internal normal standards, anorectal manometry showed decreased rectal compliance and maximum tolerable volume in patients with urgency. Nine patients reported a persistent postoperative pelvic pain (median VAS score 6). Failure of STARR to treat ODS, documented by persisting ODS symptoms, fecal urgency, or chronic pelvic pain, is often justified by the persistence or de novo onset of alteration of the anorectal anatomy at defecation. This occurs in about half of the patients, but in 40% of the cases who complained of incomplete emptying or incontinence, anatomical abnormalities were not recognized.

Modeling volume change for active flexible package of CO2-producing kimchi

Abstract As a preliminary step for optimizing the active scavenger system to confer both the proper level of carbonic product taste and the tolerable package appearance for flexible packages of kimchi, a Korean lactic acid-fermented vegetable, a mathematical model to estimate their volume change along with internal CO2 concentration was developed. Kinetics of acidity increase and CO2 production was determined by experiment of storing glass jars of 0.5 kg kimchi at 0, 10 and 20 °C. Scavenger’s CO2 absorption kinetics was formulated as gas permeation of the film sachet of Ca(OH)2. All the kinetics was combined into mass balance of CO2 where its dissolution equilibration between the product and headspace phases was described by Henry’s law. Temperature dependence of the kinetic parameters was explained by Arrhenius equation. Thermodynamic temperature effect was incorporated by Ideal Gas Law and Henry’s law constant. The developed model could estimate the behavior of a flexible package of 0.5 kg kimchi with a CO2 scavenger sachet at 5 °C and assist in the design of kimchi packages that adopt tolerable volume expansion while maintaining a desirable CO2 level for carbonic fresh flavor. The sachet film’s CO2 permeability and the active scavenger amount in the sachet were design variables affecting the volume expansion and CO2 partial pressure. Among the tested conditions, high-density polyethylene sachet of 5.5 g scavenger was the best in providing the desired characteristics.

Ultra-low volume oxygen tolerant photoinduced Cu-RDRP

We introduce the first oxygen tolerant ultra-low volume (as low as 5 μL) photoinduced Cu-RDRP of a range of hydrophobic, hydrophilic and semi-fluorinated monomers.

Permissive fluid volume in adult patients undergoing extracorporeal membrane oxygenation treatment

BackgroundExtracorporeal membrane oxygenation (ECMO) is a cardiorespiratory support technique for patients with circulatory or pulmonary failure. Frequently, large-volume fluid resuscitation is needed to ensure sufficient extracorporeal blood flow in patients initiating ECMO. However, excessive overhydration is known to increase mortality in critically ill patients. Therefore, in order to define a tolerant volume range in patients undergoing ECMO treatment, the association between cumulative fluid balance (CFB) and outcome was evaluated in patients undergoing ECMO.MethodsThis retrospective multicenter cohort study was conducted with 723 patients who underwent ECMO in three tertiary care hospitals between 2005 and 2016. CFB was calculated as total fluid input minus total fluid output during the first 3 days from ECMO initiation. The patients were divided into groups that initiated ECMO owing to cardiovascular disease (CVD)-related or non-cardiovascular disease (non-CVD)-related causes. The primary endpoint was mortality within 90 days after ECMO commencement.ResultsTotals of 406 and 317 patients were included in the CVD and non-CVD groups, respectively. In the CVD group, the mean age was 58.4 ± 17.7 years, and 68.2% were male. The mean age was 55.7 ± 15.7 years, and 65.3% were male in the non-CVD group. The median CFB values were 64.7 and 53.5 ml/kg in the CVD and non-CVD groups, respectively. Multivariable analysis using Cox proportional hazards models revealed a significantly increased risk of 90-day mortality in patients with higher CFB values in both the CVD and non-CVD groups. However, the risks were elevated only in the two CFB quartile groups with the largest CFB amounts. Cubic spline models showed that mortality risk began to increase significantly when CFB was 82.3 ml/kg in the CVD group. In patients with respiratory diseases, the mortality risk increase was significant for those with CFB levels above 189.6 ml/kg.ConclusionsMortality risk did not increase until a certain level of fluid overload was reached in patients undergoing ECMO. Adequate fluid resuscitation is critical to improving outcomes in these patients.

Current status of enteral nutrition tolerance and gastric residual volume monitoring in elderly critically ill patients in ICU

Objective To investigate the current status of monitoring gastric residual volume (GRV) and enteral nutrition (EN) tolerance in critically ill elderly patients in ICU nationwide, so as to provide evidence for finding the best assessment method of EN tolerance in critically ill elderly patients and standardizing the operation procedure. Methods A total of 724 ICU critically ill elderly patients from 22 provinces, 5 autonomous regions and 4 municipalities were selected by convenience sampling method and investigated for EN strategy management, EN pipeline maintenance, EN tolerance assessment and GRV monitoring. Results During the period of enteral nutrition in critically ill elderly patients, 461 (63.7%) of the 724 ICUs surveyed performed routine GRV monitoring, 166 (22.9%) used the EN tolerance scoring too, 156 (21.5%) used ultrasound to monitor gastric residual volume. There was no statistical difference in use of EN tolerance score tool and B-mode ultrasound monitoring among different types of ICU (P>0.05) . The incidence of vomiting and dominant aspiration in routine monitoring departments was lower than that in unconventional monitoring departments, and the difference was statistically significant (P<0.05) . Conclusions The elderly critically ill patients should be evaluated EN tolerance every day during the implementation of EN, and routine and feasible GRV monitoring should be carried out. Key words: Aged; Intensive Care Units; Tolerance of enteral nutrition; Gastric residual volume

Normal Rectal Filling Sensations in Patients with an Enlarged Rectum

BackgroundIncreased rectal volume is believed to be associated with diminished rectal sensation, i.e., rectal hyposensitivity.AimsTo demonstrate that patients with increased rectal volumes do not automatically have diminished rectal filling sensations.MethodsWe, retrospectively, observed 100 adult patients with defecation problems, and 44 healthy controls who had undergone anorectal function tests. Using the balloon retention test, we analyzed the distribution of rectal volumes and pressures at different rectal filling sensation levels.ResultsWe found variance in the distribution of rectal volumes at all levels, while rectal pressures showed a normal distribution. We found no correlation between rectal volumes and pressures (constant sensation, r = 0.140, P = 0.163, urge sensation, r = − 0.090, P = 0.375, and maximum tolerable volumes, r = − 0.091, P = 0.366), or when taking age and sex into account. The findings for the patient group were congruent with those for the control group.ConclusionsParticipants with increased rectal volumes do not experience increased rectal pressures at any sensation level. This finding, combined with the knowledge that rectal pressure triggers rectal filling sensation, indicates that rectal filling sensations in patients with increased rectal volumes are not diminished. Therefore, “rectal hyposensitivity” should be reserved for patients with increased rectal pressure thresholds, and not for “abnormally” increased rectal volume thresholds.

Beetroot-based gel supplementation improves handgrip strength and forearm muscle O2 saturation but not exercise tolerance and blood volume in jiu-jitsu athletes.

The ergogenic effect of beetroot on the exercise performance of trained cyclists, runners, kayakers, and swimmers has been demonstrated. However, whether or not beetroot supplementation presents a beneficial effect on the exercise performance of jiu-jitsu athletes remains inconclusive. Therefore, the present study assessed the effect of beetroot-based gel (BG) supplementation on maximal voluntary contraction (MVC), exercise time until fatigue (ETF), muscle O2 saturation (SmO2), blood volume (tHb), and plasma nitrate and lactate in response to handgrip isotonic exercise (HIE) in jiu-jitsu athletes. In a randomized, crossover, double-blind design, 12 jiu-jitsu athletes performed 3 sets of HIE at 40% of the MVC until fatigue after 8 days (the eighth dose was offered 120 min previous exercise) of BG supplementation or a nitrate-depleted gel (PLA), and forearm SmO2 and tHb were continuously monitored by using near-infrared spectroscopy. Blood samples were taken before, immediately after exercise, and 20 min after exercise recovery in the PLA and BG conditions. MVC was evaluated at baseline and 20 min after HIE. There was a significant reduction in ΔMVC decline after HIE in the BG condition. Forearm SmO2 during exercise recovery was significantly greater only after BG supplementation. No significant difference in ETF and tHb were observed between both BG and PLA in response to HIE. Plasma nitrate increased only after BG, whereas the exercise-induced increase in plasma lactate was significantly lower in BG when compared with PLA. In conclusion, BG supplementation may be a good nutritional strategy to improve forearm SmO2 and prevent force decline in response to exercise in jiu-jitsu athletes.

Book Review: The History of the Basel Institute for Immunology

BOOK REVIEW article Front. Immunol., 19 March 2018Sec. Immunological Tolerance and Regulation Volume 9 - 2018 | https://doi.org/10.3389/fimmu.2018.00566

Effect of Fistula in Ano Surgery on Anorectal Manometric Study

AbstractBackground: Surgical treatment of anal fistula is associated with a significant risk of impaired continence. Anorectal manometry is the most widely available tool for investigating anorectal function.Patients and Methods: Twenty patients of age ranging from twenty to sixty years old underwent treatment of anal fistula. They did anorectal manometry before and two months after management.Results: Significant decrease noted in the resting and squeezes pressure and maximal tolerable volume in the rectum.Conclusion: Anorectal manometry is a valuable tool in detecting the effect of anal fistula surgery on anorectal function even in subclinical conditions that may be helpful in opening the way for studies predicting high risk patient after anal fistula surgery to start treatment before reaching the clinical condition.

An upper bound on the particle-laden dependency of shear stresses at solid–fluid interfaces

In modern advanced manufacturing processes, such as three-dimensional printing of electronics, fine-scale particles are added to a base fluid yielding a modified fluid. For example, in three-dimensional printing, particle-functionalized inks are created by adding particles to freely flowing solvents forming a mixture, which is then deposited onto a surface, which upon curing yields desirable solid properties, such as thermal conductivity, electrical permittivity and magnetic permeability. However, wear at solid–fluid interfaces within the machinery walls that deliver such particle-laden fluids is typically attributed to the fluid-induced shear stresses, which increase with the volume fraction of added particles. The objective of this work is to develop a rigorous strict upper bound for the tolerable volume fraction of particles that can be added, while remaining below a given stress threshold at a fluid–solid interface. To illustrate the bound’s utility, the expression is applied to a series of classical flow regimes.

Anal sphincter dysfunction in patients treated with primary radiotherapy for anal cancer: a study with the functional lumen imaging probe

Background: Sphincter-sparing radiotherapy or chemoradiation are standard treatments for patients with anal cancer. The ultimate treatment goal is full recovery from anal cancer with preserved anorectal function. Unfortunately, long-term survivors often suffer from severe anorectal symptoms. The aim of the present study was to characterize changes in anorectal physiology after radiotherapy for anal cancer.Method: We included 13 patients (10 women, age 63.4 ± 1.9) treated with radiotherapy or chemoradiation for anal cancer and 14 healthy volunteers (9 women, age 61.4 ± 1.5). Symptoms were assessed with scores for fecal incontinence and low anterior resection syndrome. Anorectal physiology was examined with anorectal manometry and the Functional Lumen Imaging Probe.Results: Patients had a median Wexner fecal incontinence score of 5 (0–13) and a median LARS score of 29 (0–39). Compared to healthy volunteers, patients had lower mean (±SE) anal -resting (38 ± 5 vs. 71 ± 6, p < .001) and -squeeze pressures (76 ± 11 vs. 165 ± 15, p < .001). Patients also had lower anal yield pressure (15.5 ± 1.3 mmHg vs. 28.0 ± 2.0 mmHg, p < .001), higher distensibility, and lower resistance to flow (reduced resistance ratio of the anal canal during distension, q = 5.09, p < .001). No differences were found in median (range) rectal volumes at first sensation (70.5 (15–131) vs. 57 (18–132) ml, p > .4), urge (103 (54-176) vs. 90 (32-212), p > .6) or maximum tolerable volume (173 (86–413) vs. 119.5 (54–269) ml, p > .10).Conclusion: Patients treated with radiotherapy or chemoradiation for anal cancer have low anal resting and squeeze pressures as well as reduced resistance to distension and flow.

Study on anorectal dynamics of biofeedback therapy for fecal incontinence in patients with low rectal cancer after restorative resection

Objective This study intends to elaborate the effect of biofeedback therapy on postoperative defecation dysfunction in low rectal cancer by anorectal dynamics index, and to observe the effects and mechanism of biofeedback in the treatment of the process in detail. Methods 80 patients with low rectal cancer preparing for anterior resection were randomized for surgical treatment, treatment group 50 cases, and 30 cases in the control group. The treatment group received biofeedback therapy for 3 months, control group did not do special treatment, continuous observation patients Preoperative, before biofeedback treatment and at the end of 1, 3, 6, 9, 12 month about anorectal dynamics index and meaning, continence, feeling the change of function, defecation time and defecation time. Observed over the same period in control group during the experiment as the treatment group. Results After biofeedback training in the treatment group, the first 12 months of follow-up anal resting pressure (t=9.903, P=0.004), anal maximal systolic blood pressure (t=6.737, P=0.007)and rectal maximum tolerable volume were significantly (t=8.040, P=0.006) improved compared with before biofeedback treatment, that of (188.4±41.1) ml, (189.9±36.4) mmHg (1 mmHg=0.133 kPa) and (47.6±8.0) mmHg. But rectal sensory threshold capacity (t=2.362, P=0.823)and rectal defecation feeling capacity (t=3.507, P=0.583)were not significantly increased compared with before biofeedback therapy [(20.9±5.3) ml and (46.2±10.9) ml]. Postoperative patients in the treatment group before biological feedback therapy and biofeedback therapy for twelfth months later, anorectal defecation function was significantly improved (χ2=10.729, P=0.004), difference was statistically significant. The treatment group compared with the control group for twelfth months, the difference was statistically significant (χ2=37.777, P=0.002). Conclusion Biofeedback therapy can improve the anal function in patients with low or very low rectal cancer after restorative resection. Key words: Low rectal caicinoma; Restorative resection; Fecal incontinence; Biofeedback therapy