Habit training versus habit training with direct visual biofeedback in adults with chronic constipation: study protocol for a randomised controlled trial

Background

Constipation affects up to 20% of adults. Chronic constipation (CC) affects 1–2% of adults. Patient dissatisfaction is high; nearly 80% feel that laxative therapy is unsatisfactory and symptoms have significant impact on quality of life. There is uncertainty about the value of specialist investigations and whether equipment-intensive therapies using biofeedback confer additional benefit when compared with specialist conservative advice.

Methods/design

A three-arm, parallel-group, multicentre randomised controlled trial.

Objectives: to determine whether standardised specialist-led habit training plus pelvic floor retraining using computerised biofeedback is more clinically effective than standardised specialist-led habit training alone; to determine whether outcomes are improved by stratification based on prior investigation of anorectal and colonic pathophysiology. Primary outcome measure is response to treatment, defined as a 0.4-point (10% of scale) or greater reduction in Patient Assessment of Constipation–Quality of Life (PAC-QOL) score 6 months after the end of treatment. Other outcomes up to 12 months include symptoms, quality of life, health economics, psychological health and qualitative experience.

Hypotheses: (1) habit training (HT) with computer-assisted direct visual biofeedback (HTBF) results in an average reduction in PAC-QOL score of 0.4 points at 6 months compared to HT alone in unselected adults with CC, (2) stratification to either HT or HTBF informed by pathophysiological investigation (INVEST) results in an average 0.4-point reduction in PAC-QOL score at 6 months compared with treatment not directed by investigations (No-INVEST).

Inclusion: chronic constipation in adults (aged 18–70 years) defined by self-reported symptom duration of more than 6 months; failure of previous laxatives or prokinetics and diet and lifestyle modifications. Consenting participants (n = 394) will be randomised to one of three arms in an allocation ratio of 3:3:2: [1] habit training, [2] habit training and biofeedback or [3] investigation-led allocation to one of these arms. Analysis will be on an intention-to-treat basis.

Discussion

This trial has the potential to answer some of the major outstanding questions in the management of chronic constipation, including whether costly invasive tests are warranted and whether computer-assisted direct visual biofeedback confers additional benefit to well-managed specialist advice alone.

Trial registration

International Standard Randomised Controlled Trial Number: ISRCTN11791740. Registered on 16 July 2015.

Electronic supplementary material

The online version of this article (doi:10.1186/s13063-017-1880-0) contains supplementary material, which is available to authorized users.

Abstract P3-07-01: Selinexor, a selective inhibitor of nuclear export, demonstrates efficacy in preclinical models of triple negative breast cancer

Background: Approximately 15% of all breast cancers are categorized as triple negative (TNBC) for which the only chemotherapy is known to be effective, yet often fails to achieve remission. Nuclear exporter XPO1 (Exportin1 or CRM1) is a promising target for cancer therapy that mediates the transport of multiple tumor suppressors and cell cycle regulators that have been known to be relevant predictors in the mechanism and severity of TNBC. Given the pressing need for novel therapies for this disease, we sought to determine the antitumor effects of selinexor, a novel inhibitor of nuclear export, on triple negative breast cancers in vitro and in vivo as well as to address its mechanism of action.

Methods: 26 breast cancer cell lines of different breast cancer subtypes were treated with selinexor in vitro. Using cell proliferation assays the half maximal inhibitory concentration (IC50) was calculated using isobologram curves after 3 days of treatment; sensitivity was defined as IC50 <1000nM. We then assessed mechanistic effects on apoptosis and cell proliferation using flow cytometry analysis with annexin V and propidium iodide and using western blot analysis we also studied its effects on markers of inhibition of apoptosis. In vivo efficacy was studied as single agent and in combination with standard chemotherapy agents in TNBC patient derived xenografts (PDXs) with varying levels of sensitivity to chemotherapy as well as with varying statuses of TP53 and PIK3CA, and gene expression subtypes.

Results: Selinexor demonstrated growth inhibition in all fourteen TNBC cell lines tested; TNBC cell lines were more sensitive to selinexor (median IC50 44nM, range 11 - 550nM), compared to ER+ cells lines (median IC50 of 13000 nM, range of 40nM - > 1000 nM; P=0.017). Treatment with selinexor decreased expression levels of XPO1, as well as survivin and XIAP, and induced apoptosis. In multiple TNBC cell lines selinexor was synergistic with paclitaxel, carboplatin, eribulin and doxorubicin in vitro (median combination index 0.6, range 0.5-0.8). Selinexor as a single agent reduced tumor growth in vivo in 4 of 5 different TNBC PDX models with a median tumor growth inhibition ratio score (T/C) of 48% (range 34-59%) and demonstrated greater antitumor efficacy in combination with paclitaxel or eribulin with an average T/C score of 27% and 12% respectively.

Conclusions: Selinexor is a promising therapeutic agent for triple negative breast cancer and it has potential as a combination agent with standard chemotherapy.

Citation Format: Paez Arango N, Evans KW, Zhao M, Yuca E, Scott SM, Janku F, Ueno NT, Tripathy D, Kim C, Naing A, Funda M-B. Selinexor, a selective inhibitor of nuclear export, demonstrates efficacy in preclinical models of triple negative breast cancer [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P3-07-01.

A National Biofeedback Practitioners Service Evaluation: Focus on Chronic Idiopathic Constipation

INTRODUCTION

Within the UK, there is anecdotal evidence of disparity in the training, practice, supervision and perception of efficacy among practitioners of biofeedback therapy for chronic constipation.

AIMS

To establish the current knowledge, practice and opinions of UK practitioners.

METHODS

Between October 2012 and October 2013, a prospective service evaluation was distributed to biofeedback practitioners in the UK through academic conferences or by invitation to complete an on-line assessment form.

RESULTS

76 practitioners responded, consisting of nurses (47%), physiotherapists (35%), physiologists (12%) and others (7%). Only 45% described 'biofeedback' consistent with an accepted definition. 86% use equipment to provide sensory feedback. Methods of biofeedback varied: balloon catheter (54%), brace pump technique (78%), urge resistance (83%), irrigation (16%) and relaxation (12%). Only 65% of practitioners had attended formal training courses, and 52% considered themselves to be self-taught. 36% receive formal supervision and only 38% of those by a senior. Regular audit of outcomes is undertaken by 67%. UK-wide perception of treatment response for chronic constipation is markedly variable (mean response=57% (IQR 50-75%, SD 23%)); there were no differences in perception of treatment response between nurses or physiotherapists. Practitioners' free responses demonstrated strong positive themes of a holistic approach and an overall perception of effectiveness. Negative themes included service restrictions.

CONCLUSIONS

There is marked variation in practice, training and supervision of biofeedback therapists throughout the UK. Perceptions of efficacy vary greatly. Development of training and supervision standards is a priority as well as a consensus to standardise therapy.

Pathophysiology of fecal incontinence differs between men and women: a case-matched study in 200 patients

BACKGROUND

Fecal incontinence (FI) is a common and socially disabling condition with obstetric trauma considered the principal etiological factor. This study aimed to systematically evaluate symptom presentation and anorectal function in both females and males with FI.

METHODS

One hundred males (M) and 100 age-matched females (F) with FI presenting between 2012 and 2014 were identified from a prospectively collected database. Comparison of clinical (history, symptom profile, and severity using validated questionnaires) and anorectal physiological (manometry, rectal sensory testing, endoanal ultrasonography, and evacuation proctography) data between M and F was performed.

KEY RESULTS

Incidence of prior anal surgery (M: 28% vs F: 18%, p = 0.13) and abdominal surgery (M: 25% vs F: 26%, p = 0.90) was similar between sexes, but females had a higher incidence of previous pelvic surgery (M: 4% vs F: 47%, p < 0.001). Eighty-five females were parous and 75% reported history of traumatic vaginal delivery. There was a trend toward higher St Mark's incontinence scores in females (mean ± SD; M: 13 ± 4 vs F: 14 ± 5, p = 0.06). In men, structural sphincter abnormalities were uncommon (M: 37% vs F: 77%, p < 0.001), while impaired rectal sensation (M: 24% vs F: 7%, p = 0.001) and functional disturbances of evacuation (M: 36% vs F: 13%, p = 0.001) were more common than in women. No abnormality on all tests performed was observed in twice as many males (M: 18% vs F: 9%, p = 0.10).

CONCLUSIONS & INFERENCES

Pathophysiological mechanisms of FI differ between sexes. Anal sphincter dysfunction was an uncommon finding in males, with impaired rectal sensation and functional disturbances of evacuation much more prominent than in the female cohort. These findings are likely to impact options for symptom management.

Diagnostic disagreement between tests of evacuatory function: a prospective study of 100 constipated patients

BACKGROUND

Evacuatory dysfunction (ED) is a common cause of constipation and may be sub-classified on the basis of specialist tests. Such tests may guide treatment e.g., biofeedback therapy for 'functional' defecatory disorders (FDD). However, there is no gold standard, and prior studies have not prospectively and systematically compared all tests that are used to diagnose forms of ED.

METHODS

One hundred consecutive patients fulfilling Rome III criteria for functional constipation underwent four tests: expulsion of a rectal balloon distended to 50 mL (BE50 ) or until patients experienced the desire to defecate (BEDDV ), evacuation proctography (EP) and anorectal manometry. Yields and agreements between tests for the diagnosis of ED and FDD were assessed.

KEY RESULTS

Positive diagnostic yields for ED were: BEDDV 18%, BE50 31%, EP 38% and anorectal manometry (ARM) 68%. Agreement was substantial between the two balloon tests (k = 0.66), only fair between proctography and BE50 (k = 0.27), poor between manometry and proctography (k = 0.01), and there was no agreement between the balloon tests and manometry (k = -0.07 for both BE50 and BEDDV ). For the diagnosis of FDD, there was only fair agreement between ARM and EP (k = 0.23), ARM ± BE50 and EP (k = 0.18), ARM and EP ± BE50 (k = 0.30) and ARM ± BE50 and EP ± BE50 (k = 0.23).

CONCLUSIONS & INFERENCES

There is considerable disagreement between the results of various tests used to diagnose ED and FDD. This highlights the need for a reappraisal of both diagnostic criteria, and what represents the 'gold standard' investigation.

Characterization of transient noise in Advanced LIGO relevant to gravitational wave signal GW150914

On September 14, 2015, a gravitational wave signal from a coalescing black hole binary system was observed by the Advanced LIGO detectors. This paper describes the transient noise backgrounds used to determine the significance of the event (designated GW150914) and presents the results of investigations into potential correlated or uncorrelated sources of transient noise in the detectors around the time of the event. The detectors were operating nominally at the time of GW150914. We have ruled out environmental influences and non-Gaussian instrument noise at either LIGO detector as the cause of the observed gravitational wave signal.

Systematic review with meta-analysis: effect of fibre supplementation on chronic idiopathic constipation in adults

BACKGROUND

Chronic idiopathic constipation is a common symptom-based gastrointestinal disorder responsible for a substantial economic health service burden. Current guidelines recommend the use of fibre as a first-line treatment.

AIM

To investigate the effect of fibre (including prebiotic) supplementation on global symptom response, stool output, gut microbiota composition and adverse events in adults with chronic idiopathic constipation.

METHODS

Medline, EmBase, Web of Science, Scopus and the Cochrane central register of controlled trials were searched through to February 2016. Conference proceedings from 2003 to 2015 were hand-searched. There were no language restrictions. Forest plots with 95% CIs were generated using a random-effects model.

RESULTS

The search strategy generated 1072 citations, of which seven individual randomised controlled trials were eligible. Overall, 113 of 147 (77%) patients assigned to fibre responded to therapy, compared with 61 of 140 (44%) allocated to placebo (RR of success to respond 1.71, 95% CI 1.20-2.42, P = 0.003). Fibre significantly increased stool frequency (SMD, standardised mean difference = 0.39; 95% CI 0.03-0.76; P = 0.03) and softened stool consistency (SMD = 0.35; 95% CI 0.04-0.65; P = 0.02) compared with placebo. Flatulence was significantly higher with fibre compared to placebo (SMD 0.56, 0.12-1.00, P = 0.01). Overall quality of evidence was low.

CONCLUSIONS

This meta-analysis demonstrates that fibre is moderately effective, but also causes moderate gastrointestinal side effects. However, these findings need to be treated with caution due to a high risk of bias. Accordingly, further large, methodologically rigorous trials are required, before any definitive recommendation regarding its risk-benefit profile can be made. PROSPERO registration number CRD42014007005.

GW151226: Observation of Gravitational Waves from a 22-Solar-Mass Binary Black Hole Coalescence

We report the observation of a gravitational-wave signal produced by the coalescence of two stellar-mass black holes. The signal, GW151226, was observed by the twin detectors of the Laser Interferometer Gravitational-Wave Observatory (LIGO) on December 26, 2015 at 03:38:53 UTC. The signal was initially identified within 70 s by an online matched-filter search targeting binary coalescences. Subsequent off-line analyses recovered GW151226 with a network signal-to-noise ratio of 13 and a significance greater than 5σ. The signal persisted in the LIGO frequency band for approximately 1 s, increasing in frequency and amplitude over about 55 cycles from 35 to 450 Hz, and reached a peak gravitational strain of 3.4_{-0.9}^{+0.7}×10^{-22}. The inferred source-frame initial black hole masses are 14.2_{-3.7}^{+8.3}M_{⊙} and 7.5_{-2.3}^{+2.3}M_{⊙}, and the final black hole mass is 20.8_{-1.7}^{+6.1}M_{⊙}. We find that at least one of the component black holes has spin greater than 0.2. This source is located at a luminosity distance of 440_{-190}^{+180}  Mpc corresponding to a redshift of 0.09_{-0.04}^{+0.03}. All uncertainties define a 90% credible interval. This second gravitational-wave observation provides improved constraints on stellar populations and on deviations from general relativity.

Properties of the Binary Black Hole Merger GW150914

On September 14, 2015, the Laser Interferometer Gravitational-Wave Observatory (LIGO) detected a gravitational-wave transient (GW150914); we characterize the properties of the source and its parameters. The data around the time of the event were analyzed coherently across the LIGO network using a suite of accurate waveform models that describe gravitational waves from a compact binary system in general relativity. GW150914 was produced by a nearly equal mass binary black hole of masses 36_{-4}^{+5}M_{⊙} and 29_{-4}^{+4}M_{⊙}; for each parameter we report the median value and the range of the 90% credible interval. The dimensionless spin magnitude of the more massive black hole is bound to be <0.7 (at 90% probability). The luminosity distance to the source is 410_{-180}^{+160}  Mpc, corresponding to a redshift 0.09_{-0.04}^{+0.03} assuming standard cosmology. The source location is constrained to an annulus section of 610  deg^{2}, primarily in the southern hemisphere. The binary merges into a black hole of mass 62_{-4}^{+4}M_{⊙} and spin 0.67_{-0.07}^{+0.05}. This black hole is significantly more massive than any other inferred from electromagnetic observations in the stellar-mass regime.

GW150914: First results from the search for binary black hole coalescence with Advanced LIGO

On September 14, 2015 at 09:50:45 UTC the two detectors of the Laser Interferometer Gravitational-wave Observatory (LIGO) simultaneously observed the binary black hole merger GW150914. We report the results of a matched-filter search using relativistic models of compact-object binaries that recovered GW150914 as the most significant event during the coincident observations between the two LIGO detectors from September 12 to October 20, 2015. GW150914 was observed with a matched filter signal-to-noise ratio of 24 and a false alarm rate estimated to be less than 1 event per 203000 years, equivalent to a significance greater than 5.1 σ.

GW150914: First results from the search for binary black hole coalescence with Advanced LIGO

On September 14, 2015 at 09:50:45 UTC the two detectors of the Laser Interferometer Gravitational-wave Observatory (LIGO) simultaneously observed the binary black hole merger GW150914. We report the results of a matched-filter search using relativistic models of compact-object binaries that recovered GW150914 as the most significant event during the coincident observations between the two LIGO detectors from September 12 to October 20, 2015. GW150914 was observed with a matched filter signal-to-noise ratio of 24 and a false alarm rate estimated to be less than 1 event per 203000 years, equivalent to a significance greater than 5.1 σ.

Tests of General Relativity with GW150914

The LIGO detection of GW150914 provides an unprecedented opportunity to study the two-body motion of a compact-object binary in the large-velocity, highly nonlinear regime, and to witness the final merger of the binary and the excitation of uniquely relativistic modes of the gravitational field. We carry out several investigations to determine whether GW150914 is consistent with a binary black-hole merger in general relativity. We find that the final remnant's mass and spin, as determined from the low-frequency (inspiral) and high-frequency (postinspiral) phases of the signal, are mutually consistent with the binary black-hole solution in general relativity. Furthermore, the data following the peak of GW150914 are consistent with the least-damped quasinormal mode inferred from the mass and spin of the remnant black hole. By using waveform models that allow for parametrized general-relativity violations during the inspiral and merger phases, we perform quantitative tests on the gravitational-wave phase in the dynamical regime and we determine the first empirical bounds on several high-order post-Newtonian coefficients. We constrain the graviton Compton wavelength, assuming that gravitons are dispersed in vacuum in the same way as particles with mass, obtaining a 90%-confidence lower bound of 10^{13}  km. In conclusion, within our statistical uncertainties, we find no evidence for violations of general relativity in the genuinely strong-field regime of gravity.

Reversal of sensory deficit through sacral neuromodulation in an animal model of fecal incontinence

BACKGROUND

Sacral neuromodulation (SNM) is a treatment option for intractable fecal incontinence. The mechanism of action is unclear, however, increasing evidence for afferent somatosensory effects exists. This study's aim was to elucidate effects of acute SNM on the cerebral cortex in a rodent model of pudendal nerve injury.

METHODS

The effects of 14 Hz and 2 Hz SNM on sensory cortical activation were studied. In 32 anesthetized rats, anal canal evoked potentials (EPs) were recorded over the primary somatosensory cortex. Pudendal nerve injury was produced by 1-hour inflation of two intra-pelvic balloons. Four groups were studied: balloon injury, balloon injury plus either 14 Hz or 2 Hz SNM, sham operation. Immunohistochemistry for the neural plasticity marker polysialylated neural cell adhesion molecule (PSA-NCAM) positive cells (numerical density and location) in the somatosensory cortex was performed.

KEY RESULTS

Anal EP amplitudes diminished during balloon inflation; 14 Hz SNM restored diminished anal EPs to initial levels and 2 Hz SNM to above initial levels. Evoked potential latencies were prolonged during balloon inflation. The numerical density of PSA-NCAM positive cells increased in the SNM groups, but not in sham or balloon injury without SNM. Stimulated cortices showed clusters of PSA-NCAM positive cells in layers II, IV, and V. Post SNM changes were similar in both SNM groups.

CONCLUSIONS & INFERENCES

Sacral neuromodulation augments anal representation in the sensory cortex and restores afferent pathways following injury. PSA-NCAM positive cell density is increased in stimulated cortices and positive cells are clustered in layers II, IV, and V.

GW150914: Implications for the Stochastic Gravitational-Wave Background from Binary Black Holes

The LIGO detection of the gravitational wave transient GW150914, from the inspiral and merger of two black holes with masses ≳30M_{⊙}, suggests a population of binary black holes with relatively high mass. This observation implies that the stochastic gravitational-wave background from binary black holes, created from the incoherent superposition of all the merging binaries in the Universe, could be higher than previously expected. Using the properties of GW150914, we estimate the energy density of such a background from binary black holes. In the most sensitive part of the Advanced LIGO and Advanced Virgo band for stochastic backgrounds (near 25 Hz), we predict Ω_{GW}(f=25  Hz)=1.1_{-0.9}^{+2.7}×10^{-9} with 90% confidence. This prediction is robustly demonstrated for a variety of formation scenarios with different parameters. The differences between models are small compared to the statistical uncertainty arising from the currently poorly constrained local coalescence rate. We conclude that this background is potentially measurable by the Advanced LIGO and Advanced Virgo detectors operating at their projected final sensitivity.

GW150914: The Advanced LIGO Detectors in the Era of First Discoveries

Following a major upgrade, the two advanced detectors of the Laser Interferometer Gravitational-wave Observatory (LIGO) held their first observation run between September 2015 and January 2016. With a strain sensitivity of 10^{-23}/sqrt[Hz] at 100 Hz, the product of observable volume and measurement time exceeded that of all previous runs within the first 16 days of coincident observation. On September 14, 2015, the Advanced LIGO detectors observed a transient gravitational-wave signal determined to be the coalescence of two black holes [B. P. Abbott et al., Phys. Rev. Lett. 116, 061102 (2016)], launching the era of gravitational-wave astronomy. The event, GW150914, was observed with a combined signal-to-noise ratio of 24 in coincidence by the two detectors. Here, we present the main features of the detectors that enabled this observation. At full sensitivity, the Advanced LIGO detectors are designed to deliver another factor of 3 improvement in the signal-to-noise ratio for binary black hole systems similar in mass to GW150914.

Diagnostic accuracy study of anorectal manometry for diagnosis of dyssynergic defecation

OBJECTIVE

The diagnostic accuracy of anorectal manometry (AM), which is necessary to diagnose functional defecatory disorders (FDD), is unknown. Using blinded analysis and standardised reporting of diagnostic accuracy, we evaluated whether AM could discriminate between asymptomatic controls and patients with functional constipation (FC).

DESIGN

Derived line plots of anorectal pressure profiles during simulated defecation were independently analysed in random order by three expert observers blinded to health status in 85 women with FC and 85 age-matched asymptomatic healthy volunteers (HV). Using accepted criteria, these pressure profiles were characterised as normal (ie, increased rectal pressure coordinated with anal relaxation) or types I-IV dyssynergia. Interobserver agreement and diagnostic accuracy were determined.

RESULTS

Blinded consensus-based assessment disclosed a normal pattern in 16/170 (9%) of all participants and only 11/85 (13%) HV. The combined frequency of dyssynergic patterns (I-IV) was very similar in FC (80/85 (94%)) and HV (74/85 (87%)). Type I dyssynergia ('paradoxical' contraction) was less prevalent in FC (17/85 (20%) than in HV (31/85 (36.5%), p=0.03). After statistical correction, only type IV dyssynergia was moderately useful for discriminating between FC (39/85 (46%)) and HV (17/85 (20%)) (p=0.001, positive predictive value=70.0%, positive likelihood ratio=2.3). Interobserver agreement was substantial or moderate for identifying a normal pattern, dyssynergia types I and IV, and FDD, and fair for types II and III.

CONCLUSIONS

While the interpretation of AM patterns is reproducible, nearly 90% of HV have a pattern that is currently regarded as 'abnormal' by AM. Hence, AM is of limited utility for distinguishing between FC and HV.

Observation of Gravitational Waves from a Binary Black Hole Merger

On September 14, 2015 at 09:50:45 UTC the two detectors of the Laser Interferometer Gravitational-Wave Observatory simultaneously observed a transient gravitational-wave signal. The signal sweeps upwards in frequency from 35 to 250 Hz with a peak gravitational-wave strain of 1.0×10(-21). It matches the waveform predicted by general relativity for the inspiral and merger of a pair of black holes and the ringdown of the resulting single black hole. The signal was observed with a matched-filter signal-to-noise ratio of 24 and a false alarm rate estimated to be less than 1 event per 203,000 years, equivalent to a significance greater than 5.1σ. The source lies at a luminosity distance of 410(-180)(+160)  Mpc corresponding to a redshift z=0.09(-0.04)(+0.03). In the source frame, the initial black hole masses are 36(-4)(+5)M⊙ and 29(-4)(+4)M⊙, and the final black hole mass is 62(-4)(+4)M⊙, with 3.0(-0.5)(+0.5)M⊙c(2) radiated in gravitational waves. All uncertainties define 90% credible intervals. These observations demonstrate the existence of binary stellar-mass black hole systems. This is the first direct detection of gravitational waves and the first observation of a binary black hole merger.

Gastrointestinal motility during sleep assessed by tracking of telemetric capsules combined with polysomnography - a pilot study

Studies of gastrointestinal function during sleep are hampered by lack of applicable techniques. Recent development of a novel ambulatory telemetric capsule system, which can be used in conjunction with polysomnography, offers a solution to this problem. The 3D-Transit system consists of ingestible electromagnetic capsules traceable through a portable extracorporeal receiver while traversing the gut. During sleep monitored by polysomnography, gastrointestinal motility was concurrently investigated using 3D-Transit in nine healthy subjects. Overall, the amplitude of gastric contractions decreased with depth of sleep (light sleep, N2 versus deep sleep, N3; P<0.05). Progression through the small intestine did not change with depth of sleep (Kruskal-Wallis probability =0.1), and there was no association between nocturnal awakenings or arousals and the occurrence of colonic or small intestinal propagating movements. Basal colonic activity was suppressed during both deep sleep (P<0.05) and light sleep (P<0.05) when compared with nocturnal wake periods. In conclusion, the novel ambulatory 3D-Transit system combined with polysomnography allows minimally invasive and completely ambulatory investigation of associations between sleep patterns and gastrointestinal motility.

The use of colonic and anorectal high-resolution manometry and its place in clinical work and in research

BACKGROUND

In the esophagus, high-resolution manometry (HRM) has become a standard diagnostic tool in the investigation of suspected motility disorders. However, at the opposite end of the digestive tract (i.e., the colon and anorectum), the use of HRM still remains in its infancy, with relatively few published studies in the scientific literature. Further, the clinical utility of those studies that have been performed is largely undetermined.

PURPOSE

This review assesses all of the HRM studies published to date from both the colon and anorectum, explores the catheter types used, and attempts to determine the worth of HRM over traditional 'low-resolution' recordings from the same regions. Ultimately, this review addresses whether HRM currently provides information that will benefit patient diagnosis and treatment.

Regional gastrointestinal transit and pH studied in 215 healthy volunteers using the wireless motility capsule: influence of age, gender, study country and testing protocol

BACKGROUND

The wireless motility capsule (WMC) offers the ability to investigate luminal gastrointestinal (GI) physiology in a minimally invasive manner.

AIM

To investigate the effect of testing protocol, gender, age and study country on regional GI transit times and associated pH values using the WMC.

METHODS

Regional GI transit times and pH values were determined in 215 healthy volunteers from USA and Sweden studied using the WMC over a 6.5-year period. The effects of test protocol, gender, age and study country were examined.

RESULTS

For GI transit times, testing protocol was associated with differences in gastric emptying time (GET; shorter with protocol 2 (motility capsule ingested immediately after meal) vs. protocol 1 (motility capsule immediately before): median difference: 52 min, P = 0.0063) and colonic transit time (CTT; longer with protocol 2: median 140 min, P = 0.0189), but had no overall effect on whole gut transit time. Females had longer GET (by median 17 min, P = 0.0307), and also longer CTT by (104 min, P = 0.0285) and whole gut transit time by (263 min, P = 0.0077). Increasing age was associated with shorter small bowel transit time (P = 0.002), and study country also influenced small bowel and CTTs. Whole gut and CTTs showed clustering of data at values separated by 24 h, suggesting that describing these measures as continuous variables is invalid. Testing protocol, gender and study country also significantly influenced pH values.

CONCLUSIONS

Regional GI transit times and pH values, delineated using the wireless motility capsule (WMC), vary based on testing protocol, gender, age and country. Standardisation of testing is crucial for cross-referencing in clinical practice and future research.

Improved upper limits on the stochastic gravitational-wave background from 2009-2010 LIGO and Virgo data

Gravitational waves from a variety of sources are predicted to superpose to create a stochastic background. This background is expected to contain unique information from throughout the history of the Universe that is unavailable through standard electromagnetic observations, making its study of fundamental importance to understanding the evolution of the Universe. We carry out a search for the stochastic background with the latest data from the LIGO and Virgo detectors. Consistent with predictions from most stochastic gravitational-wave background models, the data display no evidence of a stochastic gravitational-wave signal. Assuming a gravitational-wave spectrum of Ω_{GW}(f)=Ω_{α}(f/f_{ref})^{α}, we place 95% confidence level upper limits on the energy density of the background in each of four frequency bands spanning 41.5-1726 Hz. In the frequency band of 41.5-169.25 Hz for a spectral index of α=0, we constrain the energy density of the stochastic background to be Ω_{GW}(f)<5.6×10^{-6}. For the 600-1000 Hz band, Ω_{GW}(f)<0.14(f/900  Hz)^{3}, a factor of 2.5 lower than the best previously reported upper limits. We find Ω_{GW}(f)<1.8×10^{-4} using a spectral index of zero for 170-600 Hz and Ω_{GW}(f)<1.0(f/1300  Hz)^{3} for 1000-1726 Hz, bands in which no previous direct limits have been placed. The limits in these four bands are the lowest direct measurements to date on the stochastic background. We discuss the implications of these results in light of the recent claim by the BICEP2 experiment of the possible evidence for inflationary gravitational waves.

Systematic review: the effect of prunes on gastrointestinal function

BACKGROUND

Prunes (dried plums) are high in fibre and are perceived to promote healthy gastrointestinal (GI) function.

AIM

To assess the effect of prunes on GI function through a systematic review of randomised controlled trials (RCTs).

METHODS

Sixteen electronic databases were searched, a hand search was performed and key opinion leaders were contacted. RCTs investigating the effect of prunes on GI function were included. Two reviewers independently screened relevant articles, extracted data and assessed risk of bias.

RESULTS

Four trials met the inclusion criteria, one in constipation and three in non-constipated subjects. In constipation, 3 weeks of prune consumption (100 g/day) improved stool frequency (3.5 vs. 2.8 CSBM per week, P = 0.006) and stool consistency (3.2 vs. 2.8 on Bristol stool form scale, P = 0.02) compared with psyllium (22 g/day). In non-constipated subjects, prunes softened stool consistency in one trial and increased stool weight (628 g vs. 514 g/72 h wet weight, P = 0.001) in another trial, compared with control. No trials found differences in GI symptoms between prunes and comparator. Meta-analysis was not appropriate due to heterogeneity in populations and methods. Two of the trials were limited by unclear risk of bias.

CONCLUSIONS

In constipation, prunes appear superior to psyllium for improving stool frequency and consistency, however, the evidence for other outcomes and the effects in non-constipated subjects is weak. Although prunes may be a promising intervention for the management of constipation and increasing stool weight, this needs to be confirmed by further rigorous research.

The effect of probiotics on functional constipation in adults: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Functional constipation is a prevalent, burdensome gastrointestinal disorder whose treatment remains challenging. Probiotics have been increasingly investigated in its management.

OBJECTIVE

The aim was to investigate the effect of probiotics on gut transit time, stool output, and constipation symptoms in adults with functional constipation via a systematic review and meta-analysis of randomized controlled trials (RCTs).

DESIGN

Studies were identified by searching 4 electronic databases, back-searching reference lists, contacting authors, and hand-searching abstracts. RCTs that reported administration of probiotics in adults with functional constipation were included. Two reviewers independently performed the screening, data extraction, and bias assessment. Outcome data were synthesized by using weighted mean differences (WMDs) or standardized mean differences (SMDs) with the use of a random-effects model.

RESULTS

A total of 660 records were identified of which 14 were eligible (1182 patients). Overall, probiotics significantly reduced whole gut transit time by 12.4 h (95% CI: -22.3, -2.5 h) and increased stool frequency by 1.3 bowel movements/wk (95% CI: 0.7, 1.9 bowel movements/wk), and this was significant for Bifidobacterium lactis (WMD: 1.5 bowel movements/wk; 95% CI: 0.7, 2.3 bowel movements/wk) but not for Lactobacillus casei Shirota (WMD: -0.2 bowel movements/wk; 95% CI: -0.8, 0.9 bowel movements/wk). Probiotics improved stool consistency (SMD: +0.55; 95% CI: 0.27, 0.82), and this was significant for B. lactis (SMD: +0.46; 95% CI: 0.08, 0.85) but not for L. casei Shirota (SMD: +0.26; 95% CI: -0.30, 0.82). No serious adverse events were reported. Attrition and reporting bias were high, whereas selection bias was unclear due to inadequate reporting.

CONCLUSIONS

Probiotics may improve whole gut transit time, stool frequency, and stool consistency, with subgroup analysis indicating beneficial effects of B. lactis in particular. However, caution is needed with the interpretation of these data due to their high heterogeneity and risk of bias. Adequately powered RCTs are required to better determine the species or strains, doses, and duration of use of probiotics that are most efficacious.

A systematic review of sacral nerve stimulation mechanisms in the treatment of fecal incontinence and constipation

BACKGROUND

Sacral nerve stimulation (SNS) is now well established as a treatment for fecal incontinence (FI) resistant to conservative measures and may also have utility in the management of chronic constipation; however, mechanism of action is not fully understood. End organ effects of SNS have been studied in both clinical and experimental settings, but interpretation is difficult due to the multitude of techniques used and heterogeneity of reported findings. The aim of this study was to systematically review available evidence on the mechanisms of SNS in the treatment of FI and constipation.

METHODS

Two systematic reviews of the literature (performed in accordance with the Preferred Reporting Items for Systematic reviews and Meta-Analyses framework) were performed to identify manuscripts pertaining to (a) clinical and (b) physiological effects of SNS during the management of hindgut dysfunction.

KEY RESULTS

The clinical literature search revealed 161 articles, of which 53 were deemed suitable for analysis. The experimental literature search revealed 43 articles, of which nine were deemed suitable for analysis. These studies reported results of investigative techniques examining changes in cortical, gastrointestinal, colonic, rectal, and anal function.

CONCLUSIONS & INFERENCES

The initial hypothesis that the mechanism of SNS was primarily peripheral motor neurostimulation is not supported by the majority of recent studies. Due to the large body of evidence demonstrating effects outside of the anorectum, it appears likely that the influence of SNS on anorectal function occurs at a pelvic afferent or central level.