Normative values for stool frequency and form using Rome III diagnostic criteria for functional constipation in adults: systematic review with meta-analysis.

When designing clinical trials focused on functional constipation therapies, understanding the normative values of populations selected using the Rome III criteria is important for estimating baseline symptom severity, and for power analysis and sample size calculations. The objective of this review was to determine normative ranges for stool frequency and form in adults with functional constipation (Rome III criteria). Eligible studies reported stool frequency or form; random effects meta-analysis was performed with subgroup analyses to explore sources of heterogeneity. A total of 25 studies (43 groups, 2292 subjects) were included. Pooled estimates were 2.7 (95% CI 2.4-3.0) for weekly stools and 2.4 (95% CI 2.1-2.6) for stool form (Bristol scale). Heterogeneity was high for both outcomes (both I2=96%, P<0.001). Subgroup analysis revealed that weekly bowel movement frequency was higher in larger than in smaller studies (3.1 vs. 2.3, P<0.001) and in studies conducted in Europe compared with those in the Americas (3.1 vs. 2.2, P=0.02). For stool form, the use of a daily diary versus subject recall was the sole explanatory variable (2.5 vs. 2.1, P<0.05). We conclude that adults with functional constipation have significant variation in stool frequency and form, explained in part by geography and study design.

Contemporary meta-analysis of short-term probiotic consumption on gastrointestinal transit.

AIM: To determine the efficacy of probiotic supplementation on intestinal transit time (ITT) in adults and to identify factors that influence these outcomes. METHODS: We conducted a systematic review of randomized controlled trials of probiotic supplementation that measured ITT in adults. Study quality was assessed using the Jadad scale. A random effects meta-analysis was performed with standardized mean difference (SMD) of ITT between probiotic and control groups as the primary outcome. Meta-regression and subgroup analyses examined the impact of moderator variables on SMD of ITT. RESULTS: A total of 15 clinical trials with 17 treatment effects representing 675 subjects were included in this analysis. Probiotic supplementation was moderately efficacious in decreasing ITT compared to control, with an SMD of 0.38 (95%CI: 0.23-0.53, P < 0.001). Subgroup analyses demonstrated statistically greater reductions in ITT with probiotics in subjects with vs without constipation (SMD: 0.57 vs 0.22, P < 0.01) and in studies with high vs low study quality (SMD: 0.45 vs 0.00, P = 0.01). Constipation (R (2) = 38%, P < 0.01), higher study quality (R (2) = 31%, P = 0.01), older age (R (2) = 27%, P = 0.02), higher percentage of female subjects (R (2) = 26%, P = 0.02), and fewer probiotic strains (R (2) = 20%, P < 0.05) were predictive of decreased ITT with probiotics in meta-regression. Medium to large treatment effects were identified with B. lactis HN019 (SMD: 0.67, P < 0.001) and B. lactis DN-173 010 (SMD: 0.54, P < 0.01) while other probiotic strains yielded negligible reductions in ITT relative to control. CONCLUSION: Probiotic supplementation is moderately efficacious for reducing ITT in adults. Probiotics were most efficacious in constipated subjects, when evaluated in high-quality studies, and with certain probiotic strains.

Clinical effectiveness and safety of powered exoskeleton-assisted walking in patients with spinal cord injury: systematic review with meta-analysis.

BACKGROUND: Powered exoskeletons are designed to safely facilitate ambulation in patients with spinal cord injury (SCI). We conducted the first meta-analysis of the available published research on the clinical effectiveness and safety of powered exoskeletons in SCI patients. METHODS: MEDLINE and EMBASE databases were searched for studies of powered exoskeleton-assisted walking in patients with SCI. Main outcomes were analyzed using fixed and random effects meta-analysis models. RESULTS: A total of 14 studies (eight ReWalk™, three Ekso™, two Indego(®), and one unspecified exoskeleton) representing 111 patients were included in the analysis. Training programs were typically conducted three times per week, 60-120 minutes per session, for 1-24 weeks. Ten studies utilized flat indoor surfaces for training and four studies incorporated complex training, including walking outdoors, navigating obstacles, climbing and descending stairs, and performing activities of daily living. Following the exoskeleton training program, 76% of patients were able to ambulate with no physical assistance. The weighted mean distance for the 6-minute walk test was 98 m. The physiologic demand of powered exoskeleton-assisted walking was 3.3 metabolic equivalents and rating of perceived exertion was 10 on the Borg 6-20 scale, comparable to self-reported exertion of an able-bodied person walking at 3 miles per hour. Improvements in spasticity and bowel movement regularity were reported in 38% and 61% of patients, respectively. No serious adverse events occurred. The incidence of fall at any time during training was 4.4%, all occurring while tethered using a first-generation exoskeleton and none resulting in injury. The incidence of bone fracture during training was 3.4%. These risks have since been mitigated with newer generation exoskeletons and refinements to patient eligibility criteria. CONCLUSION: Powered exoskeletons allow patients with SCI to safely ambulate in real-world settings at a physical activity intensity conducive to prolonged use and known to yield health benefits.

A common polymorphism in extracellular superoxide dismutase affects cardiopulmonary disease risk by altering protein distribution.

BACKGROUND: The enzyme extracellular superoxide dismutase (EC-SOD; SOD3) is a major antioxidant defense in lung and vasculature. A nonsynonomous single-nucleotide polymorphism in EC-SOD (rs1799895) leads to an arginine to glycine amino acid substitution at position 213 (R213G) in the heparin-binding domain. In recent human genetic association studies, this single-nucleotide polymorphism attenuates the risk of lung disease, yet paradoxically increases the risk of cardiovascular disease. METHODS AND RESULTS: Capitalizing on the complete sequence homology between human and mouse in the heparin-binding domain, we created an analogous R213G single-nucleotide polymorphism knockin mouse. The R213G single-nucleotide polymorphism did not change enzyme activity, but shifted the distribution of EC-SOD from lung and vascular tissue to extracellular fluid (eg, bronchoalveolar lavage fluid and plasma). This shift reduces susceptibility to lung disease (lipopolysaccharide-induced lung injury) and increases susceptibility to cardiopulmonary disease (chronic hypoxic pulmonary hypertension). CONCLUSIONS: We conclude that EC-SOD provides optimal protection when localized to the compartment subjected to extracellular oxidative stress: thus, the redistribution of EC-SOD from the lung and pulmonary circulation to the extracellular fluids is beneficial in alveolar lung disease but detrimental in pulmonary vascular disease. These findings account for the discrepant risk associated with R213G in humans with lung diseases compared with cardiovascular diseases.

Deregulation of the protocadherin gene FAT1 alters muscle shapes: implications for the pathogenesis of facioscapulohumeral dystrophy.

Generation of skeletal muscles with forms adapted to their function is essential for normal movement. Muscle shape is patterned by the coordinated polarity of collectively migrating myoblasts. Constitutive inactivation of the protocadherin gene Fat1 uncoupled individual myoblast polarity within chains, altering the shape of selective groups of muscles in the shoulder and face. These shape abnormalities were followed by early onset regionalised muscle defects in adult Fat1-deficient mice. Tissue-specific ablation of Fat1 driven by Pax3-cre reproduced muscle shape defects in limb but not face muscles, indicating a cell-autonomous contribution of Fat1 in migrating muscle precursors. Strikingly, the topography of muscle abnormalities caused by Fat1 loss-of-function resembles that of human patients with facioscapulohumeral dystrophy (FSHD). FAT1 lies near the critical locus involved in causing FSHD, and Fat1 mutant mice also show retinal vasculopathy, mimicking another symptom of FSHD, and showed abnormal inner ear patterning, predictive of deafness, reminiscent of another burden of FSHD. Muscle-specific reduction of FAT1 expression and promoter silencing was observed in foetal FSHD1 cases. CGH array-based studies identified deletion polymorphisms within a putative regulatory enhancer of FAT1, predictive of tissue-specific depletion of FAT1 expression, which preferentially segregate with FSHD. Our study identifies FAT1 as a critical determinant of muscle form, misregulation of which associates with FSHD.

Glutathione binding to the Bcl-2 homology-3 domain groove: a molecular basis for Bcl-2 antioxidant function at mitochondria.

Bcl-2 protects cells against mitochondrial oxidative stress and subsequent apoptosis. However, the mechanism underlying the antioxidant function of Bcl-2 is currently unknown. Recently, Bax and several Bcl-2 homology-3 domain (BH3)-only proteins (Bid, Puma, and Noxa) have been shown to induce a pro-oxidant state at mitochondria (1-4). Given the opposing effects of Bcl-2 and Bax/BH3-only proteins on the redox state of mitochondria, we hypothesized that the antioxidant function of Bcl-2 is antagonized by its interaction with the BH3 domains of pro-apoptotic family members. Here, we show that BH3 mimetics that bind to a hydrophobic surface (the BH3 groove) of Bcl-2 induce GSH-sensitive mitochondrial dysfunction and apoptosis in cerebellar granule neurons. BH3 mimetics displace a discrete mitochondrial GSH pool in neurons and suppress GSH transport into isolated rat brain mitochondria. Moreover, BH3 mimetics and the BH3-only protein, Bim, inhibit a novel interaction between Bcl-2 and GSH in vitro. These results suggest that Bcl-2 regulates an essential pool of mitochondrial GSH and that this regulation may depend upon Bcl-2 directly interacting with GSH via the BH3 groove. We conclude that this novel GSH binding property of Bcl-2 likely plays a central role in its antioxidant function at mitochondria.

Rho family GTPase inhibition reveals opposing effects of mitogen-activated protein kinase kinase/extracellular signal-regulated kinase and Janus kinase/signal transducer and activator of transcription signaling cascades on neuronal survival.

Rho family GTPases promote the survival of certain neuronal populations. However, pro-survival and pro-death signaling pathways regulated downstream of Rho GTPases are largely unknown. Cerebellar granule neurons (CGNs) exposed to Clostridium difficile toxin B (ToxB), a monoglucosyltransferase that specifically inhibits Rho GTPases, die by a mitochondrial apoptotic cascade. Using a high-throughput immunoblotting screen (BD Powerblot), we found that ToxB markedly reduced the expression of Rac1 and c-Raf, upstream components of a Rac-dependent mitogen-activated protein (MAP) kinase pathway. Moreover, ToxB rapidly suppressed a p21-activated kinase/MAP kinase kinase (MEK)/extracellular signal-regulated kinase (ERK)1/2 signaling cascade that normally promotes degradation of the Bcl-2 homology-3 (BH3)-only protein Bim, a key initiator of mitochondrial apoptosis. In contrast to c-Raf down-regulation, ToxB enhanced expression of the transcription factor, signal transducer and activator of transcription-1 (STAT1). Both STAT1 up-regulation and apoptosis induced by ToxB were prevented by a pan-inhibitor of Janus kinases (JAKs), indicating that JAK/STAT signaling was pro-apoptotic in CGNs. Most significantly, direct inhibition of MEK was sufficient to trigger JAK-dependent STAT1 expression, suggesting that cross-talk between MEK/ERK and JAK/STAT pathways plays a key role in regulating neuronal survival. Finally, ERK dephosphorylation and STAT1 up-regulation induced by ToxB were mimicked by a dominant-negative (N17) mutant of Rac1. These data suggest that the MEK/ERK cascade functions downstream of Rac GTPase to actively repress pro-apoptotic JAK/STAT signaling in healthy CGNs.

Distinct mechanisms of neuronal apoptosis are triggered by antagonism of Bcl-2/Bcl-x(L) versus induction of the BH3-only protein Bim.

Primary cerebellar granule neurons (CGNs) require depolarizing extracellular potassium for their survival. Removal of depolarizing potassium triggers CGN apoptosis that requires induction of Bim, a BH3-only Bcl-2 family member. Bim is classically thought to promote apoptosis by neutralizing pro-survival Bcl-2 proteins. To determine if this is the principal function of Bim in CGNs, we contrasted Bim-mediated apoptosis to neuronal death induced by HA14-1, a BH3-domain mimetic that antagonizes Bcl-2 and Bcl-x(L). HA14-1 elicited CGN apoptosis characterized by caspase 3 and 9 activation, cytochrome c release, conformational activation of Bax, and mitochondrial depolarization. HA14-1 provoked CGN apoptosis in the absence of Bim induction and negative regulators of Bim transcription did not prevent HA14-1-induced cell death. However, the antioxidant glutathione and its precursor, N-acetyl-l-cysteine, suppressed HA14-1-induced apoptosis. Similarly, apoptosis induced by either a structurally distinct Bcl-2/Bcl-x(L) inhibitor (compound 6) or Bcl-2 antisense oligonucleotides was diminished by glutathione. In contrast, antioxidants had no effect on CGN apoptosis provoked by either removal of depolarizing potassium or overexpression of a GFP-Bim fusion protein, two models of Bim-dependent death. These data show that antagonism of Bcl-2/Bcl-x(L) function elicits oxidative stress-dependent CGN apoptosis that is mechanistically distinct from Bim-mediated cell death. These results further indicate that, although Bcl-2/Bcl-x(L) antagonism is sufficient to induce neuronal apoptosis, Bim likely promotes neuronal death by interacting with additional proteins besides Bcl-2/Bcl-x(L).

Dynamic near-real-time magnetic resonance imaging for analyzing the velopharyngeal closure in comparison with videofluoroscopy.

PURPOSE: To demonstrate the feasibility of dynamic magnetic resonance imaging (MRI) with near-real-time temporal resolution ("real-time MRI") for analyzing the velopharyngeal closure in comparison with multiview videofluoroscopy. MATERIALS AND METHODS: Seven patients (three females and four males, 5-21 years old, mean age=11.3 years) with suspected velopharyngeal insufficiency, and one healthy volunteer were examined with videofluoroscopy and real-time MRI using a turbo-spin-echo (TSE) sequence (TR=170 msec, TE=21 msec, slice thickness=6 mm, six images per second). Imaging was done during phonation in all three image planes. The results were analyzed by two radiologists in comparison with videofluoroscopy as the standard of reference for overall image quality and the pattern of velopharyngeal closure. RESULTS: Real-time MRI correctly depicted the pattern of velopharyngeal closure in correspondence to videofluoroscopy in all cases. Concerning the movement of the pharyngeal walls, real-time MRI falsely depicted a general movement of the dorsal pharyngeal wall in one case, whereas videofluoroscopy showed no movement. In one patient, real-time MRI provided additional information by showing an asymmetric movement of the lateral pharyngeal walls that could not be depicted by videofluoroscopy due to technical limitations. Concerning image quality, the coronal plane was more difficult to evaluate with real-time MRI compared to videofluoroscopy. The axial plane was easier to analyze in real-time MRI compared to videofluoroscopy. CONCLUSION: Real-time MRI has the potential to depict the pattern of velopharyngeal closure in close correlation with videofluoroscopy, and may deliver additional information in selected cases.

The influence of oral cavity tumour treatment on the voice quality and on fundamental frequency.

This study aimed to discover whether the surgical treatment of oral cavity tumours only affects on articulation or whether it also leads to a change in voice quality and fundamental frequency. Twelve participants were examined pre- and postoperatively for mean speaking fundamental frequency, standard deviation of the mean fundamental frequency, harmonic-to-noise-ratio and intrinsic pitch. All the parameters showed a substantial postoperative change in some patients.