Evaluation and management of patients with symptoms after anti-reflux surgery.

Over the past two decades, there has been an increase in the number of anti-reflux operations being performed. This is mostly due to the use of laparoscopic techniques, the increasing prevalence of gastroesophageal reflux disease (GERD) in the population, and the increasing unwillingness of patients to take acid suppressive medications for life. Laparoscopic fundoplication is now widely available in both academic and community hospitals, has a limited length of stay and postoperative recovery time, and is associated with excellent outcomes in carefully selected patients. Although the operation has low mortality and postoperative morbidity, it is associated with late postoperative complications, such as gas bloat syndrome, dysphagia, diarrhea, and recurrent GERD symptoms. This review summarizes the diagnostic evaluation and appropriate management of such postoperative complications. If a reoperation is needed, it should be performed by experienced foregut surgeons.

Reduced expression of antimicrobial PLUNC proteins in nasal polyp tissues of patients with chronic rhinosinusitis.

BACKGROUND: Chronic rhinosinusitis (CRS) is a disease characterized by inflammation of the nasal mucosa and paranasal sinuses. This inflammation may result in part from decreased epithelial barrier and innate immune responses, leading to frequent bacterial and fungal colonization. The objectives of this study were to investigate the expression of innate immune proteins of the palate lung and nasal epithelium clone (PLUNC) family in patients with CRS. METHODS: Nasal tissue samples were collected from control subjects and CRS patients with and without nasal polyps. Expression of the members of the PLUNC family was analyzed by real-time PCR. Expression of SPLUNC1 and LPLUNC2 proteins was analyzed by ELISA, immunoblot, and immunohistochemical analysis. RESULTS: Levels of mRNA for most of the members of the PLUNC family were profoundly reduced in nasal polyps (NPs) compared to uncinate tissue from control subjects or patients with CRS. LPLUNC2 and SPLUNC1 proteins were decreased in NPs of patients with CRS compared to uncinate tissue from control subjects. Immunohistochemical data revealed that within submucosal glands of sinonasal tissues, SPLUNC1 and LPLUNC2 were differentially expressed, in serous and mucous cells, respectively. The decrease in the expression of these molecules is probably explained by a decrease in the number of glands in NPs as revealed by correlations with levels of the glandular marker lactoferrin. CONCLUSIONS: Decreased SPLUNC1 and LPLUNC2 in NPs reflect a profound decrease in the number of submucosal glands. Decreased glands may lead to a localized defect in the production and release of glandular innate defense molecules.

Dynamics and segregation of cell-matrix adhesions in cultured fibroblasts.

Here we use time-lapse microscopy to analyse cell-matrix adhesions in cells expressing one of two different cytoskeletal proteins, paxillin or tensin, tagged with green fluorescent protein (GFP). Use of GFP-paxillin to analyse focal contacts and GFP-tensin to study fibrillar adhesions reveals that both types of major adhesion are highly dynamic. Small focal contacts often translocate, by extending centripetally and contracting peripherally, at a mean rate of 19 micrometers per hour. Fibrillar adhesions arise from the medial ends of stationary focal contacts, contain alpha5beta1 integrin and tensin but not other focal-contact components, and associate with fibronectin fibrils. Fibrillar adhesions translocate centripetally at a mean rate of 18 micrometers per hour in an actomyosin-dependent manner. We propose a dynamic model for the regulation of cell-matrix adhesions and for transitions between focal contacts and fibrillar adhesions, with the ability of the matrix to deform functioning as a mechanical switch.

Common multifractality in the heart rate variability and brain activity of healthy humans.

The influence from the central nervous system on the human multifractal heart rate variability (HRV) is examined under the autonomic nervous system perturbation induced by the head-up-tilt body maneuver. We conducted the multifractal factorization analysis to factor out the common multifractal factor in the joint fluctuation of the beat-to-beat heart rate and electroencephalography data. Evidence of a central link in the multifractal HRV was found, where the transition towards increased (decreased) HRV multifractal complexity is associated with a stronger (weaker) multifractal correlation between the central and autonomic nervous systems.

Molecular cloning, expression, and mapping of the high affinity actin-capping domain of chicken cardiac tensin.

Tensin, an actin filament capping protein first purified from chicken gizzard, is localized to various types of adherens junctions in muscle and nonmuscle cells. In this paper, we describe the isolation and sequencing of tensin cDNA from a chicken cardiac library. The 6.3-kb chicken cardiac tensin cDNA encodes an open reading frame of 1,792 amino acids. Mammalian cells transfected with the chicken tensin cDNA expressed a polypeptide of approximately 200 kD recognizable by antibodies to chicken gizzard tensin. The expressed protein was incorporated into focal adhesions and other actin-containing structures in the transfected cells. To map the domain associated with tensin's high affinity, barbed-end F-actin-capping activity, bacterially expressed recombinant fusion proteins containing various segments of tensin were prepared and assayed for activity. The results of these experiments show that the high affinity capping domain (kD = 1.3 nM) lies within amino acid residues R1037-V1169. Additional studies on a shorter construct, S1061-H1145, showed that these 85 residues were sufficient for producing complete inhibition of actin polymerization and depolymerization. While this active domain is located within that of the "insertin" sequence (Weigt, C., A. Gaertner, A. Wegner, H. Korte, and H. E. Meyer. 1992. J. Mol. Biol. 227:593-595), our data showing complete inhibition of polymerization and shift in critical concentration are consistent with a simple barbed-end capping mechanism rather than the "insertin model." Our results also differ from those of a recent report (Lo, S. H., P. A. Janmey, J. H. Hartwig, and L. B. Chen. 1994. J. Cell Biol. 125:1067-1075), which concluded that their recombinant tensin has an "insertin-like" inhibitory effect on barbed-end actin polymerization, and that this activity is attributed to residues T936-R1037 (residues 888-989 in their numbering system). In our study, a fusion construct (N790-K1060) encompassing T936-R1037 had no significant effect on actin polymerization and depolymerization, even at high concentrations.

Cytochalasins inhibit nuclei-induced actin polymerization by blocking filament elongation.

Polylysine was found to induce polymerization of muscle actin in a low ionic strength buffer containing 0.4 mM MgCl2. The rate of induced polymerization was dependent on the amount and on the molecular size of the polylysine added. A similar effect was obtained by adding actin nuclei (containing about 2-4 actin subunits) cross-linked by p-N,N'-phenylenebismaleimide to G-actin under the same conditions, suggesting that the effect of polylysine is due to promotion of the formation of actin nuclei. Polymerization induced by polylysine and by cross-linked actin nuclei was inhibited by low concentrations (10(-8)-10(-6)M) of cytochalasins. Binding experiments showed that actin filaments, but not actin monomers, contained high-affinity binding sites for [3H]cytochalasin B (one site per 600 actin monomers). The relative affinity of several cytochalasins for these sites (determined by competitive displacement of [3H]dihydrocytochalasin B) was: cytochalasin D greater than cytochalasin E approximately equal to dihydrocytochalasin B. The results of this study suggest that cytochalasins inhibit nuclei-induced actin polymerization by binding to highly specific sites at the point of monomer addition, i.e., the elongation site, in actin nuclei and filaments.

Integrin dynamics and matrix assembly: tensin-dependent translocation of alpha(5)beta(1) integrins promotes early fibronectin fibrillogenesis.

Fibronectin matrix assembly is a multistep, integrin-dependent process. To investigate the role of integrin dynamics in fibronectin fibrillogenesis, we developed an antibody-chasing technique for simultaneous tracking of two integrin populations by different antibodies. We established that whereas the vitronectin receptor alpha(v)beta(3) remains within focal contacts, the fibronectin receptor alpha(5)beta(1) translocates from focal contacts into and along extracellular matrix (ECM) contacts. This escalator-like translocation occurs relative to the focal contacts at 6.5 +/- 0.7 microm/h and is independent of cell migration. It is induced by ligation of alpha(5)beta(1) integrins and depends on interactions with a functional actin cytoskeleton and vitronectin receptor ligation. During cell spreading, translocation of ligand-occupied alpha(5)beta(1) integrins away from focal contacts and along bundles of actin filaments generates ECM contacts. Tensin is a primary cytoskeletal component of these ECM contacts, and a novel dominant-negative inhibitor of tensin blocked ECM contact formation, integrin translocation, and fibronectin fibrillogenesis without affecting focal contacts. We propose that translocating alpha(5)beta(1) integrins induce initial fibronectin fibrillogenesis by transmitting cytoskeleton-generated tension to extracellular fibronectin molecules. Blocking this integrin translocation by a variety of treatments prevents the formation of ECM contacts and fibronectin fibrillogenesis. These studies identify a localized, directional, integrin translocation mechanism for matrix assembly.

Variability trend in the scale-free fluctuation of economic and market data.

Recurring trending feature of a particular duration or size can normally be observed in the scale-free fluctuation of economic and market data. While it contradicts the notion of being scale free, trends are generally believed to exist. From the explicit result of multiplicative cascade and empirical evidence, we show the presence of local cascades underlying the recurring trend and such characteristic is in fact an integral part rather than an aberration of the scale-free fluctuation.

Protein alterations in ESCC and clinical implications: a review.

Esophageal squamous cell carcinoma (ESCC) is the predominant histological subtype of esophageal cancer in Asia, characterized by high incidence and mortality rate. Although significant progress has been made in surgery and adjuvant chemoradiotherapy, the prognosis of the patients with this cancer still remains poor. Investigation into protein alterations that occurred in tumors can provide clues to discover new biomarkers for improving diagnosis and guiding targeted therapy. Hundreds of papers have appeared over the past several decades concerning protein alterations in ESCC. This review summarizes all the dysregulated proteins investigated in the disease from 187 published papers and analyzes their contributions to tumor development and progression. We document protein alterations associated with tumor metastasis and the transition from normal esophageal epithelia to dysplasia in order to reveal the most useful markers for prediction of clinical outcome, early detection, and identification of high-risk patients for targeted therapies. In particular, we discuss the largest and most rigorous studies on prognostic implications of proteins in ESCC, in which cyclin D1, p53, E-cadherin and VEGF appeared to have the strongest evidence as independent predictors of patient outcome.

Targeting the vulnerability to NAD+ depletion in B-cell acute lymphoblastic leukemia.

Although substantial progress has been made in the treatment of B-cell acute lymphoblastic leukemia (B-ALL), the prognosis of patients with either refractory or relapsed B-ALL remains dismal. Novel therapeutic strategies are needed to improve the outcome of these patients. KPT-9274 is a novel dual inhibitor of p21-activated kinase 4 (PAK4) and nicotinamide phosphoribosyltransferase (NAMPT). PAK4 is a serine/threonine kinase that regulates a variety of fundamental cellular processes. NAMPT is a rate-limiting enzyme in the salvage biosynthesis pathway of nicotinamide adenine dinucleotide (NAD) that plays a vital role in energy metabolism. Here, we show that KPT-9274 strongly inhibits B-ALL cell growth regardless of cytogenetic abnormalities. We also demonstrate the potent in vivo efficacy and tolerability of KPT-9274 in a patient-derived xenograft murine model of B-ALL. Interestingly, although KPT-9274 is a dual PAK4/NAMPT inhibitor, B-ALL cell growth inhibition by KPT-9274 was largely abolished with nicotinic acid supplementation, indicating that the inhibitory effects on B-ALL cells are mainly exerted by NAD+ depletion through NAMPT inhibition. Moreover, we have found that the extreme susceptibility of B-ALL cells to NAMPT inhibition is related to the reduced cellular NAD+ reserve. NAD+ depletion may be a promising alternative approach to treating patients with B-ALL.

Chromosome arrangement within a bacterium.

BACKGROUND: The contour length of the circular chromosome of bacteria is greater than a millimeter but must be accommodated within a cell that is only a few micrometers in length. Bacteria do not have nucleosomes and little is known about the arrangement of the chromosome inside a prokaryotic cell. RESULTS: We have investigated the arrangement of chromosomal DNA within the bacterium Bacillus subtilis by using fluorescence microscopy to visualize two sites on the chromosome simultaneously in the same cell. Indirect immunofluorescence with antibodies against the chromosome partition protein Spo0J were used to visualize the replication origin region of the chromosome. Green fluorescent protein fused to the lactose operon repressor Lacl was used to decorate tandem copies of the lactose operon operator lacO. A cassette of tandem operators was separately inserted into the chromosome near the origin (359 degrees), near the replication terminus (181 degrees), or at two points in between (90 degrees and 270 degrees). The results show that the layout of the chromosome is dynamic but is principally arranged with the origin and terminus maximally apart and the quarter points of the chromosome in between. CONCLUSIONS: The use of cytological methods to visualize two chromosomal sites in the same cell has provided a glimpse of the arrangement of a bacterial chromosome. We conclude that, to a first approximation, the folding of the bacterial chromosome is consistent with, and may preserve, the linear order of genes on the DNA.

ZNF750 is a lineage-specific tumour suppressor in squamous cell carcinoma.

ZNF750 controls epithelial homeostasis by regulating epidermal-differentiation genes, a role underscored by its pathogenic mutations in esophageal squamous cell cancers (SCCs). However, the precise role of ZNF750 in SCC cell biology remains unclear. In this study, we report that ZNF750 is exclusively deleted, mutated and underexpressed in human SCCs, and low ZNF750 expression is associated with poor survival. Restoration of wildtype, but not mutant ZNF750 protein uniquely inhibited the malignant phenotypes of SCC cells both in vitro and in vivo. Notably, ZNF750 promoted the expression of a long non-coding RNA (TINCR), which mediated both cancer-inhibition and differentiation-induction effects of ZNF750. In addition, ZNF750 potently suppressed cell migration by directly inhibiting the transactivation of LAMC2. Together, our findings characterize ZNF750 as a crucial SCC-specific suppressor and uncover its novel anticancer-associated functions.

Integrative analyses of transcriptome sequencing identify novel functional lncRNAs in esophageal squamous cell carcinoma.

Long non-coding RNAs (lncRNAs) have a critical role in cancer initiation and progression, and thus may mediate oncogenic or tumor suppressing effects, as well as be a new class of cancer therapeutic targets. We performed high-throughput sequencing of RNA (RNA-seq) to investigate the expression level of lncRNAs and protein-coding genes in 30 esophageal samples, comprised of 15 esophageal squamous cell carcinoma (ESCC) samples and their 15 paired non-tumor tissues. We further developed an integrative bioinformatics method, denoted URW-LPE, to identify key functional lncRNAs that regulate expression of downstream protein-coding genes in ESCC. A number of known onco-lncRNA and many putative novel ones were effectively identified by URW-LPE. Importantly, we identified lncRNA625 as a novel regulator of ESCC cell proliferation, invasion and migration. ESCC patients with high lncRNA625 expression had significantly shorter survival time than those with low expression. LncRNA625 also showed specific prognostic value for patients with metastatic ESCC. Finally, we identified E1A-binding protein p300 (EP300) as a downstream executor of lncRNA625-induced transcriptional responses. These findings establish a catalog of novel cancer-associated functional lncRNAs, which will promote our understanding of lncRNA-mediated regulation in this malignancy.

Ordering of mutations in acute myeloid leukemia with partial tandem duplication of MLL (MLL-PTD).

Partial tandem duplication of MLL (MLL-PTD) characterizes acute myeloid leukemia (AML) patients often with a poor prognosis. To understand the order of occurrence of MLL-PTD in relation to other major AML mutations and to identify novel mutations that may be present in this unique AML molecular subtype, exome and targeted sequencing was performed on 85 MLL-PTD AML samples using HiSeq-2000. Genes involved in the cohesin complex (STAG2), a splicing factor (U2AF1) and a poorly studied gene, MGA were recurrently mutated, whereas NPM1, one of the most frequently mutated AML gene, was not mutated in MLL-PTD patients. Interestingly, clonality analysis suggests that IDH2/1, DNMT3A, U2AF1 and TET2 mutations are clonal and occur early, and MLL-PTD likely arises after these initial mutations. Conversely, proliferative mutations (FLT3, RAS), typically appear later, are largely subclonal and tend to be unstable. This study provides important insights for understanding the relative importance of different mutations for defining a targeted therapeutic strategy for MLL-PTD AML patients.

BCOR regulates myeloid cell proliferation and differentiation.

BCOR is a component of a variant Polycomb group repressive complex 1 (PRC1). Recently, we and others reported recurrent somatic BCOR loss-of-function mutations in myelodysplastic syndrome and acute myelogenous leukemia (AML). However, the role of BCOR in normal hematopoiesis is largely unknown. Here, we explored the function of BCOR in myeloid cells using myeloid murine models with Bcor conditional loss-of-function or overexpression alleles. Bcor mutant bone marrow cells showed significantly higher proliferation and differentiation rates with upregulated expression of Hox genes. Mutation of Bcor reduced protein levels of RING1B, an H2A ubiquitin ligase subunit of PRC1 family complexes and reduced H2AK119ub upstream of upregulated HoxA genes. Global RNA expression profiling in murine cells and AML patient samples with BCOR loss-of-function mutation suggested that loss of BCOR expression is associated with enhanced cell proliferation and myeloid differentiation. Our results strongly suggest that BCOR plays an indispensable role in hematopoiesis by inhibiting myeloid cell proliferation and differentiation and offer a mechanistic explanation for how BCOR regulates gene expression such as Hox genes.

LNK (SH2B3): paradoxical effects in ovarian cancer.

LNK (SH2B3) is an adaptor protein studied extensively in normal and malignant hematopoietic cells. In these cells, it downregulates activated tyrosine kinases at the cell surface resulting in an antiproliferative effect. To date, no studies have examined activities of LNK in solid tumors. In this study, we found by in silico analysis and staining tissue arrays that the levels of LNK expression were elevated in high-grade ovarian cancer. To test the functional importance of this observation, LNK was either overexpressed or silenced in several ovarian cancer cell lines. Remarkably, overexpression of LNK rendered the cells resistant to death induced by either serum starvation or nutrient deprivation, and generated larger tumors using a murine xenograft model. In contrast, silencing of LNK decreased ovarian cancer cell growth in vitro and in vivo. Western blot studies indicated that overexpression of LNK upregulated and extended the transduction of the mitogenic signal, whereas silencing of LNK produced the opposite effects. Furthermore, forced expression of LNK reduced cell size, inhibited cell migration and markedly enhanced cell adhesion. Liquid chromatography-mass spectroscopy identified 14-3-3 as one of the LNK-binding partners. Our results suggest that in contrast to the findings in hematologic malignancies, the adaptor protein LNK acts as a positive signal transduction modulator in ovarian cancers.

Spin-label studies of erythrocytes in myotonic dystrophy: no increase in membrane fluidity.

The basic defect in myotonic dystrophy is thought to involve muscle cell membranes. Butterfield and associates have recently presented electron spin resonance data that suggest increased fluidity of erythrocyte membranes in patients with myotonic dystrophy. We studied erythrocytes from 11 patients with myotonic dystrophy and 14 age-matched controls, using spin-labeled fatty acid and ester probes. Despite attempts to reproduce the previously reported experimental conditions exactly, we found no significant differences in the electron spin resonance spectra of erythrocytes from normal and myotonic dystrophy subjects. These findings do not provide evidence of increased erythrocyte membrane fluidity in myotonic dystrophy; they fail to support the concept of an intrinsic defect of the lipid membrane in this disorder.

A quantitative analysis of pendular motion of the lower leg in spastic human subjects.

The purpose of this study was to examine gravity-induced oscillations of the lower leg in normal and spastic subjects, with a view towards evaluating a clinical test of spasticity called the "pendulum" test. Motivations for studying the pendulum test were to determine if realistic aspects of spasticity and neuromuscular control could be incorporated into a description of the motion, and to better understand the underlying neurophysiological disturbances in spasticity. For passive limb motion (in which no reflex excitation occurred), a second-order linear model did not provide an adequate description of the motion for either spastic or normal legs. Instead, system equations including nonlinear mechanical properties simulating asymmetries in the swing and amplitude dependent variations in stiffness and damping provided a more accurate description. For spastic limb motion (in which reflex excitation did occur), accurate simulation required components accounting for abnormal reflex activation, coinciding with the time course of EMG activation. These included increased stiffness and damping with their gains related to reflex EMG magnitude, and changes in the rest length of the stiffness. Comparison of numerical solutions of the equations with experimental data showed our nonlinear model simulated the motion accurately, with the variance accounted for usually exceeding 90%.

An integrated circuit implementation of the Huxley sarcomere model.

We have developed an integrated circuit to simulate the mechanical behavior demonstrated by sarcomeres found in skeletal muscle. The circuit is based upon the mathematical description of the attachment and detachment dynamics of crossbridge populations and the force generated by the crossbridges, originally formulated by A. F. Huxley. We describe the process of designing the circuit model from the mathematical model, present the sarcomere circuit implementation, and demonstrate the transient and steady-state behaviors that the fabricated circuit produces. Comparison of our results to published mechanical behavior of skeletal muscle shows qualitative similarities. We conclude that the circuit muscle model exhibits the potential for real-time simulation of muscle contractions and could be used to give engineered systems muscle-like properties.

Robustness and perturbation in the modeled cascade heart rate variability.

In this study, numerical experiments are conducted to examine the robustness of using cascade to describe the multifractal heart rate variability (HRV) by perturbing the hierarchical time scale structure and the multiplicative rule of the cascade. It is shown that a rigid structure of the multiple time scales is not essential for the multifractal scaling in healthy HRV. So long as there exists a tree structure for the multiplication to take place, a multifractal HRV and related properties can be captured by using the cascade. But the perturbation of the multiplicative rule can lead to a qualitative change. In particular, a multifractal to monofractal HRV transition can result after the product law is perturbed to an additive one at the fast time scale. We suggest that this explains the similar HRV scaling transition in the parasympathetic nervous system blockade.