The Relationship Between Vertical Ground Reaction Force, Loading Rate, and Sound Characteristics During a Single-Leg Landing.

CONTEXT: Landing kinetic outcomes are associated with injury risk and may be persistently altered after anterior cruciate ligament injury or reconstruction. However, it is challenging to assess kinetics clinically. The relationship between sound characteristics and kinetics during a limited number of functional tasks has been supported as a potential clinical alternative. OBJECTIVE: To assess the relationship between kinetics and sound characteristics during a single-leg landing task. DESIGN: Observational Setting: Laboratory. PARTICIPANTS: There was total of 26 healthy participants (15 males/11 females, age = 24.8 [3.6] y, height = 176.0 [9.1] cm, mass = 74.9 [14.4] kg, Tegner Activity Scale = 6.1 [1.1]). INTERVENTION: Participants completed single-leg landings onto a force plate while audio characteristics were recorded. MAIN OUTCOME MEASURES: Peak vertical ground reaction force, linear loading rate, instantaneous loading rate, peak sound magnitude, sound frequency were measured. Means and SDs were calculated for each participant's individual limbs. Spearman rho correlations were used to assess the relationships between audio characteristics and kinetic outcomes. RESULTS: Peak sound magnitude was positively correlated with normalized peak vertical ground reaction force (ρ = .486, P = .001); linear loading rate (ρ = .491, P = .001); and instantaneous loading rate (ρ = .298, P = .03). Sound frequency was negatively correlated with instantaneous loading rate (ρ = -.444, P = .001). CONCLUSIONS: Peak sound magnitude may be more helpful in providing feedback about an individual's normalized vertical ground reaction force and linear loading rate, and sound frequency may be more helpful in providing feedback about instantaneous loading rate. Further refinement in sound measurement techniques may be required before these findings can be applied in a clinical population.

A new method for constructing tumor specific gene co-expression networks based on samples with tumor purity heterogeneity.

Motivation: Tumor tissue samples often contain an unknown fraction of stromal cells. This problem is widely known as tumor purity heterogeneity (TPH) was recently recognized as a severe issue in omics studies. Specifically, if TPH is ignored when inferring co-expression networks, edges are likely to be estimated among genes with mean shift between non-tumor- and tumor cells rather than among gene pairs interacting with each other in tumor cells. To address this issue, we propose Tumor Specific Net (TSNet), a new method which constructs tumor-cell specific gene/protein co-expression networks based on gene/protein expression profiles of tumor tissues. TSNet treats the observed expression profile as a mixture of expressions from different cell types and explicitly models tumor purity percentage in each tumor sample. Results: Using extensive synthetic data experiments, we demonstrate that TSNet outperforms a standard graphical model which does not account for TPH. We then apply TSNet to estimate tumor specific gene co-expression networks based on TCGA ovarian cancer RNAseq data. We identify novel co-expression modules and hub structure specific to tumor cells. Availability and implementation: R codes can be found at https://github.com/petraf01/TSNet. Supplementary information: Supplementary data are available at Bioinformatics online.

Randomized trial of 1-week versus 2-week intervals for endoscopic ligation in the treatment of patients with esophageal variceal bleeding.

UNLABELLED: The appropriate interval between ligation sessions for treatment of esophageal variceal bleeding is uncertain. The optimal interval would provide variceal eradication as rapidly as possible to lessen early rebleeding while minimizing ligation-induced adverse events. We randomly assigned patients hospitalized with acute esophageal variceal bleeding who had successful ligation at presentation to repeat ligation at 1-week or 2-week intervals. Beta-blocker therapy was also prescribed. Ligation was performed at the assigned interval until varices were eradicated and then at 3 and 9 months after eradication. The primary endpoint was the proportion of patients with variceal eradication at 4 weeks. Four-week variceal eradication occurred more often in the 1-week than in the 2-week group: 37/45 (82%) versus 23/45 (51%); difference = 31%, 95% confidence interval 12%-48%. Eradication occurred more rapidly in the 1-week group (18.1 versus 30.8 days, difference = -12.7 days, 95% confidence interval -20.0 to -5.4 days). The mean number of endoscopies to achieve eradication or to the last endoscopy in those not achieving eradication was comparable in the 1-week and 2-week groups (2.3 versus 2.1), with the mean number of postponed ligation sessions 0.3 versus 0.1 (difference = 0.2, 95% confidence interval -0.02 to 0.4). Rebleeding at 4 weeks (4% versus 4%) and 8 weeks (11% versus 9%), dysphagia/odynophagia/chest pain (9% versus 2%), strictures (0% versus 0%), and mortality (7% versus 7%) were similar with 1-week and 2-week intervals. CONCLUSION: One-week ligation intervals led to more rapid eradication than 2-week intervals without an increase in complications or number of endoscopies and without a reduction in rebleeding or other clinical outcomes; the decision regarding ligation intervals may be individualized based on patient and physician preferences and local logistics and resources. (Hepatology 2016;64:549-555).

Aggressive hydration with lactated Ringer's solution reduces pancreatitis after endoscopic retrograde cholangiopancreatography.

BACKGROUND & AIMS: Pancreatitis is the most common serious complication of endoscopic retrograde cholangiopancreatography (ERCP). We performed a pilot study to determine whether aggressive periprocedural hydration with lactated Ringer's solution reduces the incidence of pancreatitis after ERCP. METHODS: Patients who underwent first-time ERCP were randomly assigned to groups (2:1) that received aggressive hydration with lactated Ringer's solution (3 mL/kg/h during the procedure, a 20-mL/kg bolus after the procedure, and 3 mL/kg/h for 8 hours after the procedure, n = 39) or standard hydration with the same solution (1.5 mL/kg/h during and for 8 hours after procedure, n = 23). Serum levels of amylase, visual analogue pain scores (scale of 0-10), and volume overload were assessed at baseline and 2, 8, and 24 hours after ERCP. The primary end point, post-ERCP pancreatitis, was defined as hyperamylasemia (level of amylase >3 times the upper limit of normal) and increased epigastric pain (≥3 points on visual analogue scale) persisting for ≥24 hours after the procedure. Secondary end points included hyperamylasemia, increased pain, and volume overload. RESULTS: None of the patients who received aggressive hydration developed post-ERCP pancreatitis, compared with 17% of patients who received standard hydration (P = .016). Hyperamylasemia developed in 23% of patients who received aggressive hydration vs 39% of those who received standard hydration (P = .116, nonsignificant); increased epigastric pain developed in 8% of patients who received aggressive hydration vs 22% of those who received standard hydration (P = .146, nonsignificant). No patients had evidence of volume overload. CONCLUSIONS: On the basis of a pilot study, aggressive intravenous hydration with lactated Ringer's solution appears to reduce the development of post-ERCP pancreatitis and is not associated with volume overload. ClinicalTrials.gov, Number: NCT 01758549.

Gastroenterologists' practice patterns for positive fecal occult blood test.

GOALS: To evaluate gastroenterologists' use of esophagogastroduodenoscopy (EGD) for positive fecal occult blood test (FOBT). BACKGROUND: Colonoscopy is recommended when an FOBT performed for colorectal cancer screening is positive. Guidelines suggest no further evaluation if anemia and gastrointestinal (GI) symptoms are absent. METHODS: Online surveys included 4 vignettes: positive FOBT in average-risk adults 50 years of age or older with/without iron-deficiency anemia and with/without upper GI symptoms. For each scenario, respondents were asked if they would perform colonoscopy only, EGD only, colonoscopy+EGD on same day, or colonoscopy followed by EGD on different day if colonoscopy was negative. RESULTS: Surveys were returned by 778 (11%) of 7094 potential responders. In patients without anemia or upper GI symptoms, 65% performed colonoscopy only; 35% added EGD (9% same day, 25% different day). EGD was added in 91% with anemia, 96% with symptoms, and 100% with anemia+symptoms. In patients with positive FOBT alone (no symptoms or anemia), multivariate analysis revealed fear of litigation as the primary factor associated with adding EGD to colonoscopy (odds ratio=4.1; 95% confidence interval, 2.3-7.3). When EGD+colonoscopy were planned for positive FOBT, private practice was associated with performing EGD on a different day (odds ratio=6.3; 95% confidence interval, 2.9-13.5 for private versus academic setting). CONCLUSIONS: One third of gastroenterologists perform EGD in addition to colonoscopy for a positive FOBT alone. Fear of litigation is the most important factor in deciding whether to add EGD to colonoscopy. When both procedures are planned, they are more likely to be performed on different days in a private practice setting than in an academic setting.

Enteric dysbiosis associated with a mouse model of alcoholic liver disease.

UNLABELLED: The translocation of bacteria and bacterial products into the circulation contributes to alcoholic liver disease. Intestinal bacterial overgrowth is common in patients with alcoholic liver disease. The aims of our study were to investigate bacterial translocation, changes in the enteric microbiome, and its regulation by mucosal antimicrobial proteins in alcoholic liver disease. We used a mouse model of continuous intragastric feeding of alcohol or an isocaloric diet. Bacterial translocation occurred prior to changes observed in the microbiome. Quantitative changes in the intestinal microflora of these animals were assessed first using conventional culture techniques in the small and large intestine. Although we found no difference after 1 day or 1 week, intestinal bacterial overgrowth was observed in the gastrointestinal tract of mice fed alcohol for 3 weeks compared with control mice fed an isocaloric liquid diet. Because <20% of all gastrointestinal bacteria can be cultured using conventional methodologies, we performed massively parallel pyrosequencing to further assess the qualitative changes in the intestinal microbiome following alcohol exposure. Sequencing of 16S ribosomal RNA genes revealed a relative abundance of Bacteroidetes and Verrucomicrobia bacteria in mice fed alcohol compared with a relative predominance of Firmicutes bacteria in control mice. With respect to the host's transcriptome, alcohol feeding was associated with down-regulation in gene and protein expression of bactericidal c-type lectins Reg3b and Reg3g in the small intestine. Treatment with prebiotics partially restored Reg3g protein levels, reduced bacterial overgrowth, and lessened alcoholic steatohepatitis. CONCLUSION: Alcohol feeding is associated with intestinal bacterial overgrowth and enteric dysbiosis. Intestinal antimicrobial molecules are dysregulated following chronic alcohol feeding contributing to changes in the enteric microbiome and to alcoholic steatohepatitis.

High-frequency Ultrasonography of the Digital and Palmar Nerve Branches of the Hand in Peripheral Nerve Diseases.

Peripheral nerve ultrasound is a well-established imaging technique to evaluate certain peripheral nerve pathologies. However, there is a poor correlation between ultrasound abnormalities of peripheral nerves and electrodiagnostic or clinical evidence of axonal loss. This is a significant limitation of peripheral nerve ultrasound, as many peripheral nerve diseases encountered in clinical settings are related to axonal loss. Furthermore, clinical and electrodiagnostic evidence of axonal loss directly correlates with disability in all peripheral nerve diseases. However, due to the floor effects often encountered in electrodiagnostic studies, these correlations, as well as definitive diagnoses, are often challenging. Thus, imaging techniques that correlate with axonal loss are essential for expanding the utility of peripheral nerve ultrasound as a potential biomarker for peripheral nerve diseases. With new technological advancements and the ever-increasing imaging capabilities of high-frequency ultrasound, the palmar and digital nerve branches of the hand can be imaged with exceptionally high resolution even using point-of-care ultrasound devices. Their superficial and distal-most anatomic locations are ideal for evaluating polyneuropathies, as these branches degenerate earliest during axonal loss. However, no studies have systematically evaluated these nerve branches to determine if they can be reproducibly measured with ultrasound. The current protocol was adapted for the systematic assessment of cross-sectional areas of the median and ulnar nerves in the palmar surface and digits of the hand. This protocol provides reference data for a subset of nerves that demonstrate high intraclass correlation coefficients between three separate ultrasonographers. Finally, as a proof of concept and to demonstrate the clinical applications of this protocol, representative data from individuals with genetically confirmed inherited polyneuropathies are compared with established normative data to examine cross-sectional area differences.

Correlation between tumor voxel dose response matrix and tumor biomarker profile in patients with head and neck squamous cell carcinoma.

BACKGROUND: We have developed a novel imaging analysis procedure that is highly predictive of local failure after chemoradiation in head and neck cancer. In this study we investigated whether any pretreatment biomarkers correlated with key imaging parameters. METHODS: Pretreatment biopsy material was available for 28 patients entered into an institutional trial of adaptive radiotherapy in which FDG-PET images were collected weekly during treatment. The biopsies were immunohistochemically stained for CD44, EGFR, GLUT1, ALDH1, Ki-67 and p53 and quantified using image analysis. Expression levels were correlated with previously derived imaging parameters, the pretreatment SUVmax and the dose response matrix (DRM). RESULTS: The different parameters of the SUVmax and DRM did not correlate with each other. We observed a positive and highly significant (p = 0.0088) correlation between CD44 expression and volume of tumor with a DRM greater than 0.8. We found no correlation between any DRM parameter and GLUT1, p53, Ki-67 and EGFR or ALDH1. GLUT1 expression did correlate with the maximum SUV0 and the volume of tumor with an SUV0 greater than 20. CONCLUSIONS: The pretreatment SUVmax and DRM are independent imaging parameters that combine to predict local recurrence. The significant correlation between CD44 expression, a known cancer stem cell (CSC) marker, and volume of tumor with a DRM greater than 0.8 is consistent with concept that specific foci of cells are responsible for tumor recurrence and that CSCs may be randomly distributed in tumors in specific niches. Dose painting these small areas may lead to improved tumor control.

Associations between isometric quadriceps strength characteristics, knee flexion angles, and knee extension moments during single leg step down and landing tasks after anterior cruciate ligament reconstruction.

BACKGROUND: It is unclear of how peak knee extension torque and early rate of torque development outcomes are related to lower extremity loading and sagittal plane movement in activities of daily living and landing tasks despite consistent deficits after anterior cruciate ligament reconstruction. The purpose of this cross-section study is to assess the ability of quadriceps strength characteristics to predict movement patterns during a step down and single leg drop crossover hopping tasks. METHODS: Fifty-two individuals with a unilateral history of anterior cruciate ligament reconstruction completed three trials of the step down and crossover hopping tasks on their involved limb. Participants completed three isometric knee extension contractions at 90° knee flexion with visual feedback to assess peak knee extension torque and rate of torque development during the first 0-100 ms and 100-200 ms of the contraction. FINDINGS: Peak knee extension torque explained the greatest variance in peak knee extension moment (R2 = 40.4%, p < 0.001) and knee flexion angle (R2 = 46.7%, p < 0.001) during the crossover hop landing. Rate of torque development (0-100 ms) was the only predictor of knee flexion angle (R2 = 19.8%, p = 0.01) at initial contact during the crossover hopping landing. Rate of torque development (100-200 ms) explained 17.6% of the variance in peak knee extension moment during the step down (p = .03). INTERPRETATION: Peak knee extension torque and early rate of torque development outcomes demonstrate limited relationships between movement of activities of daily living and sport-specific tasks. These limitations should be considered when interpreting the results of isometric strength testing in a clinical setting.

Thyroid hormone exerts site-specific effects on SRC-1 and NCoR expression selectively in the neonatal rat brain.

Thyroid hormone receptors (TRs) are ligand-gated transcription factors. Recently, many coregulator proteins have been identified that interact with steroid/TRs and are required for the activation or repression of hormone sensitive genes. We tested whether steroid receptor coactivator-1 (SRC-1) and nuclear corepressor (N-CoR) expression is altered by hypothyroidism in rat brains on gestational day 16 and postnatal day 15. We found that both SRC-1 and N-CoR mRNA levels were decreased in the cortex and dentate gyrus of 6-n-propyl-2 thiouracil treated rats only on P15, while mRNA levels for both genes were increased in the same CA3 region of the brains. These findings do not support the idea that cofactors are involved in the compensatory mechanisms for conserving TH action, but they do suggest that hypothyroidism affects the responsiveness of tissues to steroid hormones by altering the expression of necessary cofactors.

Bacterial translocation and changes in the intestinal microbiome associated with alcoholic liver disease.

Alcoholic liver disease progresses through several stages of tissue damage, from simple steatosis to alcoholic hepatitis, fibrosis, or cirrhosis. Alcohol also affects the intestine, increases intestinal permeability and changes the bacterial microflora. Liver disease severity correlates with levels of systemic bacterial products in patients, and experimental alcoholic liver disease is dependent on gut derived bacterial products in mice. Supporting evidence for the importance of bacterial translocation comes from animal studies demonstrating that intestinal decontamination is associated with decreased liver fibrogenesis. In addition, mice with a gene mutation or deletion encoding receptors for either bacterial products or signaling molecules downstream from these receptors, are resistant to alcohol-induced liver disease. Despite this strong association, the exact molecular mechanism of bacterial translocation and of how changes in the intestinal microbiome contribute to liver disease progression remains largely unknown. In this review we will summarize evidence for bacterial translocation and enteric microbial changes in response to alcoholic liver injury and chronic alcoholic liver disease. We will further describe consequences of intestinal dysbiosis on host biology. We finally discuss how therapeutic interventions may modify the gastrointestinal microflora and prevent or reduce alcoholic liver disease progression.

Presence of multiple sites containing polar material in spherical Escherichia coli cells that lack MreB.

In rod-shaped bacteria, certain proteins are specifically localized to the cell poles. The nature of the positional information that leads to the proper localization of these proteins is unclear. In a screen for factors required for the localization of the Shigella sp. actin assembly protein IcsA to the bacterial pole, a mutant carrying a transposon insertion in mreB displayed altered targeting of IcsA. The phenotype of cells containing a transposon insertion in mreB was indistinguishable from that of cells containing a nonpolar mutation in mreB or that of wild-type cells treated with the MreB inhibitor A22. In cells lacking MreB, a green fluorescent protein (GFP) fusion to a cytoplasmic derivative of IcsA localized to multiple sites. Secreted full-length native IcsA was present in multiple faint patches on the surfaces of these cells in a pattern similar to that seen for the cytoplasmic IcsA-GFP fusion. EpsM, the polar Vibrio cholerae inner membrane protein, also localized to multiple sites in mreB cells and colocalized with IcsA, indicating that localization to multiple sites is not unique to IcsA. Our results are consistent with the requirement, either direct or indirect, for MreB in the restriction of certain polar material to defined sites within the cell and, in the absence of MreB, with the formation of ectopic sites containing polar material.

Regulation of IcsP, the outer membrane protease of the Shigella actin tail assembly protein IcsA, by virulence plasmid regulators VirF and VirB.

The Shigella outer membrane protease IcsP removes the actin assembly protein IcsA from the bacterial surface, and consequently modulates Shigella actin-based motility and cell-to-cell spread. Here, we demonstrate that IcsP expression is undetectable in mutants lacking either of two transcriptional activators, VirF and VirB. In wild-type Shigella spp., virB expression is entirely dependent on VirF; therefore, to circumvent this regulatory cascade, we independently expressed VirF or VirB in Shigella strains lacking both activators and measured both IcsP levels and transcription from the icsP promoter. Our results show that VirB significantly enhanced icsP transcription, even in the absence of VirF. In contrast, when VirF was induced in the absence of VirB, VirF had variable effects. The regulation of icsP is distinctly different from the regulation of the gene encoding its major substrate, icsA, which is activated by VirF and not VirB. We propose that the different pathways regulating icsA and icsP may be critical to the modulation of IcsA-mediated actin-based motility by IcsP.

IcsA, a polarly localized autotransporter with an atypical signal peptide, uses the Sec apparatus for secretion, although the Sec apparatus is circumferentially distributed.

Asymmetric localization of proteins is essential to many biological functions of bacteria. Shigella IcsA, an outer membrane protein, is localized to the old pole of the bacillus, where it mediates assembly of a polarized actin tail during infection of mammalian cells. Actin tail assembly provides the propulsive force for intracellular movement and intercellular dissemination. Localization of IcsA to the pole is independent of the amino-terminal signal peptide (Charles, M., Perez, M., Kobil, J.H., and Goldberg, M.B., 2001, Proc Natl Acad Sci USA 98: 9871-9876) suggesting that IcsA targeting occurs in the bacterial cytoplasm and that its secretion across the cytoplasmic membrane occurs only at the pole. Here, we characterize the mechanism by which IcsA is secreted across the cytoplasmic membrane. We present evidence that IcsA requires the SecA ATPase and the SecYEG membrane channel (translocon) for secretion. Our data suggest that YidC is not required for IcsA secretion. Furthermore, we show that polar localization of IcsA is independent of SecA. Finally, we demonstrate that while IcsA requires the SecYEG translocon for secretion, components of this apparatus are uniformly distributed within the membrane. Based on these data, we propose a model for coordinate polar targeting and secretion of IcsA at the bacterial pole.