bluuebunny/crossref_metadata_2025 huggingface dataset:
Infection by Tubercular Mycobacteria Is Spread by Nonlytic Ejection from Their Amoeba Hosts
Authors: Hagedorn Monica , Rohde Kyle H. , Russell David G. , Soldati Thierry
Published: March 2009

To generate efficient vaccines and cures for
Mycobacterium tuberculosis
, we need a far better understanding of its modes of infection, persistence, and spreading. Host cell entry and the establishment of a replication niche are well understood, but little is known about how tubercular mycobacteria exit host cells and disseminate the infection. Using the social amoeba
Dictyostelium
as a genetically tractable host for pathogenic mycobacteria, we discovered that
M. tuberculosis
and
M. marinum
, but not
M. avium
, are ejected from the cell through an actin-based structure, the ejectosome. This conserved nonlytic spreading mechanism requires a cytoskeleton regulator from the host and an intact mycobacterial ESX-1 secretion system. This insight offers new directions for research into the spreading of tubercular mycobacteria infections in mammalian cells.
Development and Characterization of Mouse Models of Infection with Aerosolized
Brucella melitensis
and
Brucella suis
Authors: Smither Sophie J. , Perkins Stuart D. , Davies Carwyn , Stagg Anthony J. , Nelson Michelle , Atkins Helen S.
Published: March 2009

There is a need to identify vaccines that can protect against
Brucella
, a potential bioterrorism agent. We have developed mouse models of infection with aerosolized
Brucella melitensis
and
Brucella suis
and demonstrated their utility for the evaluation of vaccines using the model live
B. melitensis
vaccine strain Rev.1.
Evaluation of an Epitope-Blocking Enzyme-Linked Immunosorbent Assay for the Diagnosis of West Nile Virus Infections in Humans
Authors: Loroño-Pino M. A. , Farfan-Ale J. A. , Blitvich B. J. , Beebe J. L. , Jarman R. G. , Beaty B. J.
Published: March 2009

An epitope-blocking enzyme-linked immunosorbent assay (b-ELISA) was evaluated for the diagnosis of West Nile virus (WNV) infections in humans. Sera from patients diagnosed with WNV infections from an outbreak in 2003 in Colorado and from patients diagnosed with dengue virus infections from Mexico and Thailand were tested with the b-ELISA. The b-ELISAs were performed using the WNV-specific monoclonal antibody (MAb) 3.1112G and the flavivirus-specific MAb 6B6C-1. Although the WNV-specific b-ELISA was effective in diagnosing WNV infections in humans from Colorado, it was not efficacious for diagnosing WNV infections in serum specimens from Mexico and Thailand. In serum specimens from patients from Colorado, the WNV b-ELISA and the WNV plaque reduction neutralization test showed an overall agreement of 91%. The sensitivity and specificity of the WNV b-ELISA were 89% and 92%, respectively, with a false-positive rate of 5%, based on receiver operating characteristic analysis. In contrast, false-positive rate results in specimens from the countries of Mexico and Thailand, where flaviviruses are endemic, were 79% and 80%, presumably due to the presence of antibodies resulting from previous dengue virus infections in Mexico and/or Japanese encephalitis virus infections or vaccination in Thailand. Thus, in regions where people have experienced previous or multiple flavivirus infections, the use of the b-ELISA for WNV diagnosis is contraindicated.
Genotypic Characterization of
Enterocytozoon bieneusi
in Specimens from Pigs and Humans in a Pig Farm Community in Central Thailand
Authors: Leelayoova Saovanee , Piyaraj Phunlerd , Subrungruang Ittisak , Pagornrat Wacharee , Naaglor Tawee , Phumklan Sirowan , Taamasri Paanjit , Suwanasri Jiraporn , Mungthin Mathirut
Published: March 2009

We determined that 15.7% of pigs and 1.4% of humans in a pig farm community in central Thailand harbored
Enterocytozoon bieneusi
. Genotyping of
E. bieneusi
from pigs showed genotypes O, E, and H. However, only genotype A was found in human subjects. This indicates nonzoonotic transmission of
E. bieneusi
in this community.
Adenovirus Activates Complement by Distinctly Different Mechanisms In Vitro and In Vivo: Indirect Complement Activation by Virions In Vivo
Authors: Tian Jie , Xu Zhili , Smith Jeffrey S. , Hofherr Sean E. , Barry Michael A. , Byrnes Andrew P.
Published: March 2009

Understanding innate immunity is key to improving the safety of adenovirus (Ad) vectors for systemic gene therapy. Ad has been shown to activate complement in vitro, but activation of complement after Ad injection in vivo has not been directly measured. Using complement protein C3a as a marker of complement activation, we show that types 2 and 5 human Ads cause rapid complement activation after intravenous injection in mice. Unexpectedly, the mechanisms in vivo were different than those in vitro. Antibodies were critical for the activation of complement by Ad in vitro, but antibodies were not required in vivo. The classical pathway was required in vitro, whereas complement activation in vivo involved both classical and nonclassical pathways as well as the reticuloendothelial system. Remarkably, the entry-deficient Ad mutantts1 was completely unable to activate complement in vivo even though it was fully able to activate complement in vitro. This result demonstrates that the complement system senses intravenously injected Ad primarily by detecting the effects of Ad on cells rather than through direct interaction of complement with virions. Encouragingly, shielding Ad with polyethylene glycol was effective at reducing complement activation both in vitro and in vivo. In summary, intravenously injected Ad rapidly activates complement through multiple pathways, but these pathways are different than those identified by in vitro studies. In vitro studies are poorly predictive of in vivo mechanisms because Ad virions activate complement through indirect mechanisms in vivo.
Kaposi's Sarcoma-Associated Herpesvirus K-bZIP Protein Is Necessary for Lytic Viral Gene Expression, DNA Replication, and Virion Production in Primary Effusion Lymphoma Cell Lines
Authors: Lefort Sylvain , Flamand Louis
Published: March 2009

Kaposi's sarcoma-associated herpesvirus (KSHV) is the causative agent of three human proliferative disorders, namely, Kaposi's sarcoma, primary effusion lymphomas (PEL), and multicentric Castleman's disease. Lytic DNA replication of KSHV, which is essential for viral propagation, requires the binding of at least two KSHV proteins, replication and transactivation activator (RTA) and K-bZIP, on the lytic origin of replication. Moreover, K-bZIP physically interacts with RTA and represses its transactivation activity on several viral promoters in transient transfection assays. To evaluate the physiological roles of K-bZIP in the context of PEL, we generated BCBL-1 cells with a tetracycline (Tet)-inducible small hairpin RNA (shRNA) directed against the K8 mRNA to knock down K-bZIP expression at different points during KSHV's life cycle. Using this model, we demonstrate that in the absence of K-bZIP expression, dramatic decreases in
orf50
,
orf57
, and
orf26
transcript expression are observed. Similar effects were seen at the protein level for RTA (immediate-early protein) and K8.1 (late protein) expression. Interestingly, a direct correlation between K-bZIP levels and viral lytic mRNAs was noticed. As a consequence of K-bZIP knockdown, viral DNA replication and virion production were severely impaired. The same effects were observed following knockdown of K-bZIP in another PEL cell line, BC3. Finally, using shRNA-K8-inducible 293 cells, we report that de novo synthesis of K-bZIP is not necessary for initiation of infection and latency establishment. These data support the concept that K-bZIP is essential for lytic viral gene expression, viral DNA replication, and virus propagation in PEL cells.
Structural Comparison of Different Antibodies Interacting with Parvovirus Capsids
Authors: Hafenstein Susan , Bowman Valorie D. , Sun Tao , Nelson Christian D. S. , Palermo Laura M. , Chipman Paul R. , Battisti Anthony J. , Parrish Colin R. , Rossmann Michael G.
Published: March 2009

The structures of canine parvovirus (CPV) and feline parvovirus (FPV) complexed with antibody fragments from eight different neutralizing monoclonal antibodies were determined by cryo-electron microscopy (cryoEM) reconstruction to resolutions varying from 8.5 to 18 Å. The crystal structure of one of the Fab molecules and the sequence of the variable domain for each of the Fab molecules have been determined. The structures of Fab fragments not determined crystallographically were predicted by homology modeling according to the amino acid sequence. Fitting of the Fab and virus structures into the cryoEM densities identified the footprints of each antibody on the viral surface. As anticipated from earlier analyses, the Fab binding sites are directed to two epitopes, A and B. The A site is on an exposed part of the surface near an icosahedral threefold axis, whereas the B site is about equidistant from the surrounding five-, three-, and twofold axes. One antibody directed to the A site binds CPV but not FPV. Two of the antibodies directed to the B site neutralize the virus as Fab fragments. The differences in antibody properties have been linked to the amino acids within the antibody footprints, the position of the binding site relative to the icosahedral symmetry elements, and the orientation of the Fab structure relative to the surface of the virus. Most of the exposed surface area was antigenic, although each of the antibodies had a common area of overlap that coincided with the positions of the previously mapped escape mutations.
Improved Survival in Rhesus Macaques Immunized with Modified Vaccinia Virus Ankara Recombinants Expressing Simian Immunodeficiency Virus Envelope Correlates with Reduction in Memory CD4+T-Cell Loss and Higher Titers of Neutralizing Antibody
Authors: Ourmanov Ilnour , Kuwata Takeo , Goeken Robert , Goldstein Simoy , Iyengar Ranjani , Buckler-White Alicia , Lafont Bernard , Hirsch Vanessa M.
Published: March 2009

Previous studies demonstrated that immunization of macaques with simian immunodeficiency virus (SIV) Gag-Pol and Env recombinants of the attenuated poxvirus modified vaccinia virus Ankara (MVA) provided protection from high viremia and AIDS following challenge with a pathogenic strain of SIV. Although all animals became infected, plasma viremia was significantly reduced in animals that received the MVA-SIV recombinant vaccines compared with animals that received nonrecombinant MVA. Most importantly, the reduction in viremia resulted in a significant increase in median and cumulative survival. Continued analysis of these animals over the subsequent 9 years has shown that they maintain a survival advantage, although all but two of the macaques have progressed to AIDS. Importantly, improved survival correlated with preservation of memory CD4+T cells in the peripheral blood. The greatest survival advantage was observed in macaques immunized with regimens containing SIV Env, and the titer of neutralizing antibodies to the challenge virus prior to or shortly following challenge correlated with preservation of CD4+T cells. These data are consistent with a role for neutralizing antibodies in nonsterilizing protection from high viremia and associated memory CD4+T-cell loss.
Structural and electronic properties of pentacene/pentacenequinone thin films prepared by Langmuir–Blodgett technique
Authors: Weis Martin , Gmucová Katarína , Haško Daniel , Müllerová Jarmila
Published: March 2009

Structural and electronic properties of pentacene/pentacenequinone thin films prepared on various solid-state substrates by the Langmuir–Blodgett technique are reported. Amorphous structure of the prepared films has been proved by XRD measurements. Oxygen-related defects have been identified in the Langmuir–Blodgett films as a consequence of the exposure of pentacene Langmuir layer to air. Crystallization induced by thermal treatment of the prepared amorphous thin films has been observed. Electronic properties of pentacene/ pentacenequinone Langmuir–Blodgett films have been investigated in the contact-less architecture using electrochemical techniques. The energy band diagram of the amorphous pentacene/pentacenequinone Langmuir–Blodgett film on a metallic surface was constructed from the obtained electrochemical data.
ON RANDERS METRICS OF QUADRATIC RIEMANN CURVATURE
Authors: LI BENLING , SHEN ZHONGMIN
Published: March 2009

In this paper, we study Randers metrics with quadratic Riemann curvature as in the Riemannian case. We find equations that characterize R-quadratic Randers metrics. In particular, we show that R-quadratic Randers metrics must have constant S-curvature.
NUMERICAL SIMULATION FOR NUCLEATED VEHICLE EXHAUST PARTICULATE MATTERS VIA THE TEMOM/LES METHOD
Authors: YU MINGZHOU , LIN JIANZHONG , CHAN TATLEUNG
Published: March 2009

The combination of large eddy simulation (LES) and newly proposed Taylor-series expansion method of moments (TEMOM) is performed for simulating particulate matters emitted from vehicle engine tailpipe. The momentum, heat and mass transfer, binary homogeneous nucleation, Brownian coagulation, Brownian and turbulent diffusion, condensation and thermophoresis are simultaneously taken into account. Good agreements between the experimental and simulated results with respect to the pollutant dispersion are obtained. Compared to other published methods, the present TEMOM requires the least computational time with much accuracy for predicting nanoparticle dynamics. The instantaneous results show that large eddies dominate the evolution of particulate dynamics as exhaust develops, while binary homogeneous sulfuric-water nucleation mainly appears at the interface between the exhaust and ambient cool gases. The increasing of fuel sulfur content and relative humidity or the decreasing of environment temperature leads to an increase in particulate product rate, while volume-averaged particle diameter increases with increasing fuel sulfur content and environment temperature. The variation of geometric standard deviation suggests the nucleated particles eventually approach the asymptotic distribution in the dilution atmosphere, and this distribution is independent of the fuel sulfur content. The variance of upstream turbulence intensity significantly affects the evolution of particulate matters inside the plume.
THE MULTI-DIMENSIONAL NATURE OF UNIVERSITY INCUBATORS: CAPABILITY/RESOURCE EMPHASIS PHASES
Authors: TODOROVIC ZELIMIR WILLIAM , SUNTORNPITHUG NICHAYA
Published: March 2009

Recognizing the potential of institutional entrepreneurship, public universities are actively establishing university incubators. Literature on university entrepreneurship, university incubators, and entrepreneurship education allows us to develop a conceptual framework, identifying the multi-dimensional nature of incubator tenant firm development. Building on the precepts of resource based view theory, this paper posits the existence of dynamic element of incubator activity and relates it to the dynamic element of entrepreneurship education. Further, the role of entrepreneurship education and a community network are presented as instrumental in enabling effective collaborations. This framework contributes to the literature by highlighting the need for a multi-dimensional approach in research of incubator tenant firms. The framework also suggests effective university involvement with incubator tenant firms, as a potential university capability.
MOTIVATIONAL IMPACT OF ROLE MODELS AS MODERATED BY "IDEAL" VS. "OUGHT SELF-GUIDES" IDENTIFICATIONS
Authors: RADU MIRUNA , LOUÉ CHRISTOPHE
Published: March 2009

This experimental study tests the hypothesis that symbolic role models' impact on entrepreneurial self-efficacy and behavioural intention varies according to whether models appeal to the observers' "ideal self" or "ought self". We measure the effects of exposure to role models narratives appealing to the desire of either self-achievement or self-commitment as motivators to engage in an entrepreneurial project while still in the university and to start a business after graduation. 44 French undergraduate students enrolled in an entrepreneurial curriculum participated to this research during the Fall 2006.
STUDY OF A GENERALIZED FRAGMENTATION MODEL FOR SPRAYS
Authors: LEGER NICHOLAS , VASSEUR ALEXIS F.
Published: March 2009

We study a mathematical model for sprays which takes into account particle break-up due to drag forces. In particular, we establish the existence of global weak solutions to a system of incompressible Navier–Stokes equations coupled with a Boltzmann-like kinetic equation. We assume the particles initially have bounded radii and bounded velocities relative to the gas, and we show that those bounds remain as the system evolves. One interesting feature of the model is the apparent accumulation of particles with arbitrarily small radii. As a result, there can be no nontrivial hydrodynamical equilibrium for this system.
Swelling and pressure-volume relationships in the dermis measured by osmotic-stress technique
Authors: McGee Maria P. , Morykwas Michael , Levi-Polyachenko Nicole , Argenta Louis
Published: March 2009

Water transfer across the extracellular matrix (ECM) involves interstitial osmotic forces in as yet unclear ways. In particular, the traditional values of Starling forces cannot adequately explain fluid transfer rates. Here, we reassess these forces by analyzing fluid transfer in live pig and human dermal explants. Pressure potentials were controlled with inert polymers adjusted by membrane osmometry (range = 3–219 mmHg), and fluid transfer in and out of the explants was followed by sequential precision weighing. Water motional freedom in the dermis was examined by NMR. In pigs, mean hydration pressure (HP; the pressure at which volume did not change) was 107 ± 22 and 47 ± 12 (SE) mmHg at 4°C and 37°C ( P = 0.012, paired t-test, n = 7). Volume changes observed in response to pressure potential were reversible. The equation, Volume change = Vmax/[1+(time/ T1/2) d], where Vmax is maximal volume change; T1/2, time at volume = 1/2 Vmax; and d, a rate parameter, was fitted to experimental progression curves ( r2 > 0.9), yielding Vmax values linearly related to pressure, with mean slopes −3.5 ± 0.28 and −2.6 ± 0.21(SE) μl·g−1·mmHg−1 at 4°C and 37°C. NMR spin-spin relaxation times ( T2) varied within 200- to 400-μm distances in directions perpendicular to the epidermis, with slopes reaching 0.03 ms/μm. Results support a mechanism in which fluid transport across the ECM is locally regulated at micrometer scales by cell- and fiber-gel-dependent osmomechanical forces. The large HP helps to explain the fast interstitial in/out flow rates observed clinically.
Sex-dependent regulation of hypoxic ventilation in mice and humans is mediated by erythropoietin
Authors: Soliz Jorge , Thomsen Jonas Juhl , Soulage Christophe , Lundby Carsten , Gassmann Max
Published: March 2009

Acclimatization to hypoxic exposure relies on an elevated ventilation and erythropoietic activity. We recently proposed that erythropoietin (Epo) links both responses: apart from red blood cell production, cerebral and plasma Epo interact with the central and peripheral respiratory centers. Knowing that women cope better than men with reduced oxygen supply (as observed at high altitude), we analyzed the hypoxic ventilatory response in Epo-overexpressing transgenic male and female mice with high Epo levels in brain and plasma (Tg6) or in wild-type animals injected with recombinant human Epo (rhEpo). Exposure to moderate and severe hypoxia as well as to hyperoxia and injection of domperidone, a potent peripheral ventilatory stimulant, revealed that the presence of transgenic or rhEpo extensively increased the hypoxic ventilatory response in female mice compared with their corresponding male siblings. Alterations of catecholamines in the brain stem's respiratory centers were also sex dependent. In a proof-of-concept study, human volunteers were intravenously injected with 5,000 units rhEpo and subsequently exposed to 10% oxygen. Compared with men, the hypoxic ventilatory response was significantly increased in women. We conclude that Epo exerts a sex-dependent impact on hypoxic ventilation improving the response in female mice and in women that most probably involves sexual hormones. Our data provides an explanation as to why women are less susceptible to hypoxia-associated syndromes than men.
The calcimimetic AMG 641 accelerates regression of extraosseous calcification in uremic rats
Authors: Lopez Ignacio , Mendoza Francisco J. , Guerrero Fatima , Almaden Yolanda , Henley Charles , Aguilera-Tejero Escolastico , Rodriguez Mariano
Published: March 2009

The purpose of the present study was to test the hypothesis that extraskeletal calcification regresses in uremic rats after reduction in phosphorus intake and treatment with calcimimetics. Extraosseous calcification was induced in five to six nephrectomized rats fed a high-phosphorus (1.2%) diet who received calcitriol (80 ng/kg ip) every other day for a period of 14 days. Next, dietary phosphorus was reduced to 0.6%, and rats were treated with vehicle ( n = 20), calcitriol [80 ng/kg ip/48 h ( n = 20)], or the calcimimetic AMG 641 [1.5 mg/kg sc/48 h ( n = 20)]. Aortic and soft-tissue calcium and phosphorus content was evaluated after 14 and 28 days. At 28 days, reduction of phosphorus intake resulted in a significant decrease in tissue mineral content in vehicle- and AMG 641-treated rats but not in rats receiving calcitriol. Aortic calcium and phosphorus was lower in rats treated with AMG 641 (96.7 ± 26.4 mg/g) than in rats receiving vehicle (178.3 ± 38.6 mg/g). An infiltrate of phagocytic cells expressing the calcium-sensing receptor was identified in areas surrounding foci of calcification. Additional studies in parathyroidectomized rats demonstrated that AMG 641 increased the urinary excretion of calcium (6.2 ± 0.6 vs. 3.1 ± 0.5 mg/day, vehicle) ( P < 0.001). In conclusion, experimentally induced extraosseous calcification in uremic rats can be partially resolved by reducing phosphorus intake; the addition of calcimimetics may accelerate the regression process through mechanisms potentially involving a direct stimulatory effect on mineral phagocytic cells plus an increase in urinary calcium excretion.
Effects of food texture and head posture on oropharyngeal swallowing
Authors: Tsukada Tetsu , Taniguchi Hiroshige , Ootaki Sachiko , Yamada Yoshiaki , Inoue Makoto
Published: March 2009

This study aimed to describe the electromyographic (EMG) activity patterns of the genioglossus (GG) and suprahyoid (SHy) muscles during swallowing. The effects of changes in food texture/consistency and head posture on transport of the swallowed bolus were also investigated. Participants were 10 normal adults. Test foods consisted of a liquid, a syrup, or 4 ml of paste made from 0.5% or 1.0% agar. Each food was swallowed with the head in one of three positions, and EMGs and videofluorographic (VF) images were recorded. Mean values of onset, peak, and offset times, peak amplitude, area, and duration of the EMG burst were measured. The total swallowing time, oral ejection time, pharyngeal transit time, clearance time, fauces transit time, and upper esophageal sphincter (UES) transit time were measured. The GG muscle burst patterns showed two peaks (GG1 and GG2) during each swallowing. The offset time and duration of the GG1 burst and the onset, peak, and offset times and duration of both the GG2 and SHy bursts were significantly affected by food texture. There were no significant differences in bolus transit time among the different experimental conditions. Regression analyses demonstrated significant linear relationships between the tongue tip touching the palate and the peak of the GG1 burst, between passage of the bolus tail at the fauces and offset of the GG1 burst, between passage of the bolus tail at the UES and peak of the GG2 burst, and between passage of the bolus tail at the UES and offset of the SHy burst. These results demonstrate that the duration, but not the amplitude, of tongue and suprahyoid muscle activity were increased with increasing hardness of food during swallowing and that the bolus transit time can be fixed within a certain range of physical food properties.
Role of Glycinergic Inhibition in Shaping Activity of Saccadic Burst Neurons
Authors: Iwamoto Yoshiki , Kaneko Hitoshi , Yoshida Kaoru , Shimazu Hiroshi
Published: March 2009

The immediate premotor signals for saccades are created at the level of medium-lead burst neurons (MLBNs). During fixations, MLBNs receive tonic inhibition from omnipause neurons (OPNs), which use glycine as a neurotransmitter. To elucidate the role of this inhibition, we studied discharge patterns of horizontal MLBNs following iontophoretic application of strychnine, a glycine-receptor antagonist, in alert cats. Three-barrel micropipettes were used for extracellular recording and iontophoresis. After application of strychnine, MLBNs exhibited spontaneous discharge and visual responses during intersaccadic intervals. Spikes were evoked by single-pulse stimulation of the contralateral superior colliculus (SC). These results show that MLBNs receive substantial excitatory input during intersaccadic intervals and that inhibitory action of OPNs is indeed necessary to prevent MLBNs from firing. Strychnine also affected saccade-related activity of MLBNs. The burst of activity, as in normal conditions, declined rapidly before the end of saccades but was followed by low rate spike activity, which continued beyond the end of saccades. This suggests that in normal conditions, the termination of saccades is determined by resumed inhibitory action of OPNs and not by termination of excitatory input to MLBNs. In addition, the firing rate and the number of spikes during saccades increased after strychnine application, suggesting that MLBNs receive glycinergic inhibition of non-OPN origin as well. We conclude that glycinergic inhibition plays essential roles in the maintenance of stable fixation, the termination of saccades, and the regulation of saccade size and velocity.
Molecular evolution of the junctophilin gene family
Authors: Garbino Alejandro , van Oort Ralph J. , Dixit Sayali S. , Landstrom Andrew P. , Ackerman Michael J. , Wehrens Xander H. T.
Published: March 2009

Junctophilins (JPHs) are members of a junctional membrane complex protein family important for the physical approximation of plasmalemmal and sarcoplasmic/endoplasmic reticulum membranes. As such, JPHs facilitate signal transduction in excitable cells between plasmalemmal voltage-gated calcium channels and intracellular calcium release channels. To determine the molecular evolution of the JPH gene family, we performed a phylogenetic analysis of over 60 JPH genes from over 40 species and compared conservation across species and different isoforms. We found that JPHs are evolutionary highly conserved, in particular the membrane occupation and recognition nexus motifs found in all species. Our data suggest that an ancestral form of JPH arose at the latest in a common metazoan ancestor and that in vertebrates four isoforms arose, probably following two rounds of whole genome duplications. By combining multiple prediction techniques with sequence alignments, we also postulate the presence of new important functional regions and candidate sites for posttranslational modifications. The increasing number of available sequences yields significant insight into the molecular evolution of JPHs. Our analysis is consistent with the emerging concept that JPHs serve dual important functions in excitable cells: structural assembly of junctional membrane complexes and regulation of intracellular calcium signaling pathways.
MIMO System Reduction Using Modified Pole Clustering and Genetic Algorithm
Authors: Vishwakarma C. B. , Prasad R.
Published: March 2009

A new mixed method for reducing the order of the large-scale linear dynamic multi-input-multi-output (MIMO) systems has been presented. In this method, the common denominator polynomial of the reduced-order transfer function matrix is synthesized by using modified pole clustering while the coefficients of the numerator elements are computed by minimizing the integral square error between the time responses of the original and reduced system element using Genetic Algorithm. The modified pole clustering generates more dominant cluster centres than cluster centres obtained by pole clustering technique already available in literature. The proposed algorithm is computer-oriented and comparable in quality. This method guarantees stability of the reduced model if the original high-order system is stable. The algorithm of the proposed method is illustrated with the help of an example and the results are compared with the other well-known reduction techniques.
Logistic Regression and Linear Discriminant Analyses in Evaluating Factors Associated with Asthma Prevalence among 10- to 12-Years-Old Children: Divergence and Similarity of the Two Statistical Methods
Authors: Antonogeorgos George , Panagiotakos Demosthenes B. , Priftis Kostas N. , Tzonou Anastasia
Published: March 2009

Logistic regression and discriminant analyses are both applied in order to predict the probability of a specific categorical outcome based upon several explanatory variables (predictors). The aim of this work is to evaluate the convergence of these two methods when they are applied in data from the health sciences. For this purpose, we modeled the association of several factors with the prevalence of asthma symptoms with both the two methods and compared the result. In conclusion, logistic and discriminant analyses resulted in similar models.
Angiotensinogen Delays Angiogenesis and Tumor Growth of Hepatocarcinoma in Transgenic Mice
Authors: Vincent François , Bonnin Philippe , Clemessy Maud , Contrerès Jean-Olivier , Lamandé Noël , Gasc Jean-Marie , Vilar José , Hainaud Patricia , Tobelem Gérard , Corvol Pierre , Dupuy Evelyne
Published: March 2009

Angiotensinogen, a member of the serpin family, is involved in the suppression of tumor growth and metastasis. To investigate whether human angiotensinogen protects against tumor progression in vivo, we established an original bitransgenic model in which transgenic mice expressing human angiotensinogen (Hu-AGT-TG mice) were crossed with a transgenic mouse model of hepatocellular carcinoma (HCC-TG mice). Bitransgenic mice overexpressing human angiotensinogen (HCC/Hu-AGT-TG) had a significantly longer survival time than the HCC-TG mice and a reduction of both tumor growth and blood flow velocities in the liver. This antitumor effect of angiotensinogen is related to a reduced angiogenesis, impaired expression of endothelial arterial markers (active Notch4, Delta-like 4 ligand, and ephrin B2) with a decrease of arterial vessel density in HCC/Hu-AGT-TG mice liver. Overexpression of human angiotensinogen decreases angiogenesis, and prevents tumor sinusoids from remodeling and arterialization, thus delaying tumor progression in vivo. [Cancer Res 2009;69(7):2853–60]
Modulation of Caspase-Independent Cell Death Leads to Resensitization of Imatinib Mesylate–Resistant Cells
Authors: Lavallard Vanessa J. , Pradelli Ludivine A. , Paul Audrey , Bénéteau Marie , Jacquel Arnaud , Auberger Patrick , Ricci Jean-Ehrland
Published: March 2009

Imatinib mesylate is widely used for the treatment of patients with chronic myelogenous leukemia (CML). This compound is very efficient in killing Bcr-Abl–positive cells in a caspase-dependent manner. Nevertheless, several lines of evidence indicated that caspase-mediated cell death (i.e., apoptosis) is not the only type of death induced by imatinib. The goal of our study was to evaluate the importance of the newly described caspase-independent cell death (CID) in Bcr-Abl–positive cells. We established in several CML cell lines that imatinib, in conjunction with apoptosis, also induced CID. CID was shown to be as efficient as apoptosis in preventing CML cell proliferation and survival. We next investigated the potential implication of a recently identified mechanism used by cancer cells to escape CID through overexpression of the glycolytic enzyme glyceraldehyde-3-phosphate dehydrogenase (GAPDH). We showed here, in several CML cell lines, that GAPDH overexpression was sufficient to induce protection from CID. Furthermore, imatinib-resistant Bcr-Abl–positive cell lines were found to spontaneously overexpress GAPDH. Finally, we showed that a GAPDH partial knockdown, using specific short hairpin RNAs, was sufficient to resensitize those resistant cells to imatinib-induced cell death. Taken together, our results indicate that CID is an important effector of imatinib-mediated cell death. We also established that GAPDH overexpression can be found in imatinib-resistant Bcr-Abl–positive cells and that its down-regulation can resensitize those resistant cells to imatinib-induced death. Therefore, drugs able to modulate GAPDH administered together with imatinib could find some therapeutic benefits in CML patients. [Cancer Res 2009;69(7):3013–20]
A Novel Prostate Cancer Susceptibility Locus at 19q13
Authors: Hsu Fang-Chi , Sun Jielin , Wiklund Fredrik , Isaacs Sarah D. , Wiley Kathleen E. , Purcell Lina D. , Gao Zhengrong , Stattin Pär , Zhu Yi , Kim Seong-Tae , Zhang Zheng , Liu Wennuan , Chang Bao-Li , Walsh Patrick C. , Duggan David , Carpten John D. , Isaacs William B. , Grönberg Henrik , Xu Jianfeng , Zheng S. Lilly
Published: March 2009

A two-stage genome-wide association study (GWAS) of the Cancer Genetic Markers of Susceptibility (CGEMS) initiative identified single nucleotide polymorphisms (SNP) in 150 regions across the genome that may be associated with prostate cancer (PCa) risk. We filtered these results to identify 43 independent SNPs where the frequency of the risk allele was consistently higher in cases than in controls in each of the five CGEMS study populations. Genotype information for 22 of these 43 SNPs was obtained either directly by genotyping or indirectly by imputation in our PCa GWAS of 500 cases and 500 controls selected from a population-based case-control study in Sweden [Cancer of the Prostate in Sweden (CAPS)]. Two of these 22 SNPs were significantly associated with PCa risk (P < 0.05). We then genotyped these two SNPs in the remaining cases (n = 2,393) and controls (n = 1,222) from CAPS and found that rs887391 at 19q13 was highly associated with PCa risk (P = 9.4 × 10−4). A similar trend of association was found for this SNP in a case-control study from Johns Hopkins Hospital (JHH), albeit the result was not statistically significant. Altogether, the frequency of the risk allele of rs887391 was consistently higher in cases than controls among each of seven study populations examined, with an overall P = 3.2 × 10−7 from a combined allelic test. A fine-mapping study in a 110-kb region at 19q13 among CAPS and JHH study populations revealed that rs887391 was the most strongly associated SNP in the region. Additional confirmation studies of this region are warranted. [Cancer Res 2009;69(7):2720–3]
Triggering of Toll-like Receptor 4 Expressed on Human Head and Neck Squamous Cell Carcinoma Promotes Tumor Development and Protects the Tumor from Immune Attack
Authors: Szczepanski Miroslaw J. , Czystowska Malgorzata , Szajnik Marta , Harasymczuk Malgorzata , Boyiadzis Michael , Kruk-Zagajewska Aleksandra , Szyfter Witold , Zeromski Jan , Whiteside Theresa L.
Published: March 2009

Toll-like receptors (TLR) expressed on inflammatory cells play a key role in host defense against pathogens, benefiting the host. TLR are also expressed on tumor cells. To evaluate the role of TLR in tumor cells, we investigated TLR4 signaling effects on human head and neck squamous cell carcinoma (HNSCC). Tumor tissues were obtained from 27 patients with laryngeal and 12 with oral cavity cancers. Normal mucosa was obtained from 10 patients with nonneoplastic disorders. Smears for bacteria were taken from all patients during surgery. TLR4 expression in tumors and HNSCC cell lines (PCI-1, PCI-13, and PCI-30) was detected by reverse transcription-PCR and immunohistochemistry. Cell growth, apoptosis, nuclear factor-κB (NF-κB) translocation, and MyD88 and IRAK-4 expression, as well as Akt phosphorylation were measured following tumor cell exposure to the TLR4 ligand lipopolysaccharide (LPS). Tumor cell sensitivity to NK-92–mediated lysis was evaluated in 4-hour 51Cr-release assays. Cytokine levels in HNSCC supernatants were measured in Luminex-based assays. TLR4 was expressed in all tumors, HNSCC cell lines, and normal mucosa. The TLR4 expression intensity correlated with tumor grade. LPS binding to TLR4 on tumor cells enhanced proliferation, activated phosphatidylinositol 3-kinase/Akt pathway, up-regulated IRAK-4 expression, induced nuclear NF-κB translocation, and increased production (P < 0.05) of interleukin (IL)-6, IL-8, vascular endothelial growth factor, and granulocyte macrophage colony-stimulating factor. TLR4 triggering protected tumor cells from lysis mediated by NK-92 cells. TLR4 ligation on tumor cells supports HNSCC progression. [Cancer Res 2009;69(7):3105–13]
Inhibition of NOTCH Signaling by Gamma Secretase Inhibitor Engages the RB Pathway and Elicits Cell Cycle Exit in T-Cell Acute Lymphoblastic Leukemia Cells
Authors: Rao Sudhir S. , O'Neil Jennifer , Liberator Cole D. , Hardwick James S. , Dai Xudong , Zhang Theresa , Tyminski Edyta , Yuan Jing , Kohl Nancy E. , Richon Victoria M. , Van der Ploeg Lex H.T. , Carroll Pamela M. , Draetta Giulio F. , Look A. Thomas , Strack Peter R. , Winter Christopher G.
Published: March 2009

NOTCH signaling is deregulated in the majority of T-cell acute lymphoblastic leukemias (T-ALL) as a result of activating mutations in NOTCH1. Gamma secretase inhibitors (GSI) block proteolytic activation of NOTCH receptors and may provide a targeted therapy for T-ALL. We have investigated the mechanisms of GSI sensitivity across a panel of T-ALL cell lines, yielding an approach for patient stratification based on pathway activity and also providing a rational combination strategy for enhanced response to GSI. Whereas the NOTCH1 mutation status does not serve as a predictor of GSI sensitivity, a gene expression signature of NOTCH pathway activity does correlate with response, and may be useful in the selection of patients more likely to respond to GSI. Furthermore, inhibition of the NOTCH pathway activity signature correlates with the induction of the cyclin-dependent kinase inhibitors CDKN2D (p19INK4d) and CDKN1B (p27Kip1), leading to derepression of RB and subsequent exit from the cell cycle. Consistent with this evidence of cell cycle exit, short-term exposure of GSI resulted in sustained molecular and phenotypic effects after withdrawal of the compound. Combination treatment with GSI and a small molecule inhibitor of CDK4 produced synergistic growth inhibition, providing evidence that GSI engagement of the CDK4/RB pathway is an important mechanism of GSI action and supports further investigation of this combination for improved efficacy in treating T-ALL. [Cancer Res 2009;69(7):3060–8]
MUC1-Induced Transcriptional Programs Associated with Tumorigenesis Predict Outcome in Breast and Lung Cancer
Authors: Khodarev Nikolai N. , Pitroda Sean P. , Beckett Michael A. , MacDermed Dhara M. , Huang Lei , Kufe Donald W. , Weichselbaum Ralph R.
Published: March 2009

The Mucin 1 (MUC1) oncoprotein is aberrantly overexpressed in diverse human malignancies including breast and lung cancer. Although MUC1 modulates the activity of several transcription factors, there is no information regarding the effects of MUC1 on global gene expression patterns and the potential role of MUC1-induced genes in predicting outcome for cancer patients. We have developed an experimental model of MUC1-induced transformation that has identified the activation of gene families involved in oncogenesis, angiogenesis, and extracellular matrix remodeling. A set of experimentally derived MUC1-induced genes associated with tumorigenesis was applied to the analysis of breast and lung adenocarcinoma cancer databases. A 35-gene MUC1-induced tumorigenesis signature predicts significant decreases in both disease-free and overall survival in patients with breast (n = 295) and lung (n = 442) cancers. The data show that the MUC1 oncoprotein contributes to the regulation of genes that are highly predictive of clinical outcome in breast and lung cancer patients. [Cancer Res 2009;69(7):2833–7]
Clinical and Biological Effects of Valproic Acid as a Histone Deacetylase Inhibitor on Tumor and Surrogate Tissues: Phase I/II Trial of Valproic acid and Epirubicin/FEC
Authors: Munster Pamela , Marchion Douglas , Bicaku Elona , Lacevic Mira , Kim Jongphil , Centeno Barbara , Daud Adil , Neuger Anthony , Minton Susan , Sullivan Daniel
Published: March 2009

Purpose: The aim was to study the biological and molecular effects of the histone deacetylase (HDAC) inhibitor, valproic acid, in patients with solid tumor malignancies.

Experimental Design: A phase I dose escalation of valproic acid given on days 1 to 3 followed by epirubicin (day 3) was followed by a dose expansion of valproic acid combined with 5-fluorouracil, epirubicin, and cyclophosphamide (FEC100). Pharmacodynamic and pharmacokinetic studies entailed valproic acid and epirubicin plasma levels and their interaction, the effects of valproic acid on histone acetylation in peripheral blood mononuclear cells (PBMC) and tumor cells at baseline and day 3, and baseline expression of HDAC2 and HDAC6 as therapeutic targets.

Results: Forty-four patients were enrolled in the phase I part, with a disease-specific cohort expansion of 15 breast cancer patients (median age, 55 years; range, 28-66 years) receiving 120 mg/kg/day valproic acid followed by FEC100. Partial responses were seen in 9 of 41 (22%) patients during the phase I part. Objective responses were seen in 9 of 14 (64%) evaluable patients at the dose expansion with a median number of 6 administered cycles. Predominant toxicities were valproic acid–associated somnolence and epirubicin-induced myelosuppression. Valproic acid plasma levels were associated with short-term, reversible depletion of WBC and neutrophils within 48 hours. Histone acetylation in tumor samples and in PBMCs correlated with valproic acid levels and was further linked to baseline HDAC2 but not to HDAC6 expression.

Conclusion: Valproic acid is a clinically relevant HDAC inhibitor, and PBMCs may serve as a surrogate for tumor histone acetylation in solid tumor malignancies. HDAC2 should be further considered as a relevant therapeutic target.
Microarray Analysis of Early Stage Serous Ovarian Cancers Shows Profiles Predictive of Favorable Outcome
Authors: Berchuck Andrew , Iversen Edwin S. , Luo Jingqin , Clarke Jennifer P. , Horne Hisani , Levine Douglas A. , Boyd Jeff , Alonso Miguel A. , Secord Angeles Alvarez , Bernardini Marcus Q. , Barnett Jason C. , Boren Todd , Murphy Susan K. , Dressman Holly K. , Marks Jeffrey R. , Lancaster Johnathan M.
Published: March 2009

Purpose: Although few women with advanced serous ovarian cancer are cured, detection of the disease at an early stage is associated with a much higher likelihood of survival. We previously used gene expression array analysis to distinguish subsets of advanced cancers based on disease outcome. In the present study, we report on gene expression of early-stage cancers and validate our prognostic model for advanced-stage cancers.

Experimental Design: Frozen specimens from 39 stage I/II, 42 stage III/IV, and 20 low malignant potential cancers were obtained from four different sites. A linear discriminant model was used to predict survival based upon array data.

Results: We validated the late-stage survival model and show that three of the most differentially expressed genes continue to be predictive of outcome. Most early-stage cancers (38 of 39 invasive, 15 of 20 low malignant potential) were classified as long-term survivors (median probabilities 0.97 and 0.86). MAL, the most differentially expressed gene, was further validated at the protein level and found to be an independent predictor of poor survival in an unselected group of advanced serous cancers (P = 0.0004).

Conclusions: These data suggest that serous ovarian cancers detected at an early stage generally have a favorable underlying biology similar to advanced-stage cases that are long-term survivors. Conversely, most late-stage ovarian cancers seem to have a more virulent biology. This insight suggests that if screening approaches are to succeed it will be necessary to develop approaches that are able to detect these virulent cancers at an early stage.
Dietary Omega-3 Fatty Acids, Cyclooxygenase-2 Genetic Variation, and Aggressive Prostate Cancer Risk
Authors: Fradet Vincent , Cheng Iona , Casey Graham , Witte John S.
Published: March 2009

Purpose: Dietary intake of long-chain ω-3 (LC n-3) polyunsaturated fatty acids may reduce inflammation and in turn decrease risk of prostate cancer development and progression. This potential effect may be modified by genetic variation in cyclooxygenase-2 (COX-2), a key enzyme in fatty acid metabolism and inflammation.

Experimental Design: We used a case-control study of 466 men diagnosed with aggressive prostate cancer and 478 age- and ethnicity-matched controls. Diet was assessed with a semiquantitative food frequency questionnaire, and nine COX-2 tag single nucleotide polymorphisms (SNP) were genotyped. We used logistic regression models to estimate odds ratios (OR) for association and interaction.

Results: Increasing intake of LC n-3 was strongly associated with a decreased risk of aggressive prostate cancer (Ptrend ≤ 0.0001). The OR (95% confidence interval) for prostate cancer comparing the highest with the lowest quartile of n-3 intake was of 0.37 (0.25-0.54). The LC n-3 association was modified by SNP rs4648310 (+8897 A/G), flanking the 3′ region of COX-2 (Pinteraction = 0.02). In particular, the inverse association was even stronger among men with this variant SNP. This reflected the observation that men with low LC n-3 intake and the variant rs4648310 SNP had an increased risk of disease (OR, 5.49; 95% confidence interval, 1.80-16.7), which was reversed by increasing intake of LC n-3.

Conclusions: Dietary LC n-3 polyunsaturated fatty acids appear protective for aggressive prostate cancer, and this effect is modified by the COX-2 SNP rs4648310. Our findings support the hypothesis that LC n-3 may impact prostate inflammation and carcinogenesis through the COX-2 enzymatic pathway.
Variable Clinical Presentations of Nasal and Waldeyer Ring Natural Killer/T-Cell Lymphoma
Authors: Li Ye-Xiong , Liu Qing-Feng , Fang Hui , Qi Shu-Nan , Wang Hua , Wang Wei-Hu , Song Yong-Wen , Lu Jiade , Jin Jing , Wang Shu-Lian , Liu Yue-Ping , Lu Ning , Liu Xin-Fan , Yu Zi-Hao
Published: March 2009

Purpose: To determine the clinical characteristics, prognosis, and treatment outcome for patients with nasal natural killer (NK)/T-cell lymphoma (N-NKTL) and Waldeyer ring NK/T-cell lymphoma (WR-NKTL).

Experimental Design: A total of 145 patients with N-NKTL and 95 patients with WR-NKTL were compared.

Results: Compared with N-NKTL, WR-NKTL exhibited distinct differences in clinical features with a propensity for nodal involvement, more advanced stages, low elevated lactate dehydrogenase, intermediate chemosensitivity, and a favorable prognosis. Compared with patients with WR-NKTL, patients with N-NKTL were associated with a lower overall response (54% versus 89%) and higher persistent or progressive disease after initial chemotherapy (46% versus 11%; P = 0.000). The 5-year overall survival and progression-free survival rates were 67% and 56% for N-NKTL and 65% and 47% for WR-NKTL, respectively. Patients with stage II WR-NKTL showed favorable prognosis compared with those with stage II N-NKTL. Compared with radiotherapy alone, patients with early-stage WR-NKTL that received radiotherapy and chemotherapy showed a superior progression-free survival and improved overall survival. In contrast, the addition of chemotherapy to radiotherapy did not provide any survival benefit for patients with early-stage N-NKTL.

Conclusions: N-NKTL and WR-NKTL represent heterogeneous groups with variable clinical features, responses, prognosis, and treatment options.