bluuebunny/crossref_metadata_2025 huggingface dataset:
A novel dephosphorylation‐activated conductance in a mouse renal collecting duct cell line
Authors: Laycock S. , Taylor H. C. , Haigh C. , Lee A. T. , Cooper G. J. , Ong A. C. M. , Robson L.
Published: May 2009

Autosomal dominant polycystic kidney disease (ADPKD) is one of the most common inherited renal diseases. It is associated with the progressive development of renal tubular cysts, which may subsequently lead to renal failure. Studies into the genetic basis of ADPKD have identified two genes, PKD1 and PKD2, that are mutated in ADPKD patients. The PKD1 and PKD2 genes encode for two different proteins, TRPP1 and TRPP2. Previous studies have demonstrated the presence of both TRPP1 and TRPP2 in the renal collecting duct cell line M8. The aim of the following study was to investigate the functional properties of cation currents in these cells and to examine the effect of overexpression of TRPP1 using a transgenic cell model (M7). In M8 cells, initial whole cell currents were low. However, over time there was activation of a flow‐sensitive current, which was inhibited by gadolinium (IGd). The IGd was more selective for cations over anions, but did not discriminate between monovalent cations and was Ca2+ permeable. Activation of IGd was dependent on the presence of Ca2+ and also required dephosphorylation. The protein phosphatase 2A inhibitor okadaic acid prevented activation of IGd, suggesting that protein phosphatase 2A plays an important role in channel activation. The properties and magnitude of IGd were unaffected in M7 cells, suggesting that overexpression of TRPP1 was without effect. IGd was selectively inhibited by an antibody raised against the C‐terminus of TRPP2. However, its selectivity profile was different to TRPP2, suggesting that it is attributable to a TRPP2‐like channel or a TRPP2‐containing heteromeric channel. In conclusion, these data describe the functional identification of a novel dephosphorylation‐ and flow‐activated TRPP2‐related channel in mouse collecting duct cells.
Increased Diversity of Arbuscular Mycorrhizal Fungi in a Long-Term Field Experiment via Application of Organic Amendments to a Semiarid Degraded Soil
Authors: del Mar Alguacil Maria , Díaz-Pereira Elvira , Caravaca Fuensanta , Fernández Diego A. , Roldán Antonio
Published: May 2009

In this study, we tested whether communities of arbuscular mycorrhizal (AM) fungi associated with roots of plant species forming vegetative cover as well as some soil parameters (amounts of phosphatase and glomalin-related soil protein, microbial biomass C and N concentrations, amount of P available, and aggregate stability) were affected by different amounts (control, 6.5 kg m−2, 13.0 kg m−2, 19.5 kg m−2, and 26.0 kg m−2) of an urban refuse (UR) 19 years after its application to a highly eroded, semiarid soil. The AM fungal small-subunit (SSU) rRNA genes were subjected to PCR, cloning, single-stranded conformation polymorphism analysis, sequencing, and phylogenetic analyses. One hundred sixteen SSU rRNA sequences were analyzed, and nine AM fungal types belonging toGlomusgroups A and B were identified: three of them were present in all the plots that had received UR, and six appeared to be specific to certain amendment doses. The community of AM fungi was more diverse after the application of the different amounts of UR. The values of all the soil parameters analyzed increased proportionally with the dose of amendment applied. In conclusion, the application of organic wastes enhanced soil microbial activities and aggregation, and the AM fungal diversity increased, particularly when a moderate dose of UR (13.0 kg m−2) was applied.
Silencing of NADPH-Dependent Oxidoreductase Genes (yqhDanddkgA) in Furfural-Resistant EthanologenicEscherichia coli
Authors: Miller E. N. , Jarboe L. R. , Yomano L. P. , York S. W. , Shanmugam K. T. , Ingram L. O.
Published: May 2009

Low concentrations of furfural are formed as a side product during the dilute acid hydrolysis of hemicellulose. Growth is inhibited by exposure to furfural but resumes after the complete reduction of furfural to the less toxic furfuryl alcohol. Growth-based selection was used to isolate a furfural-resistant mutant of ethanologenicEscherichia coliLY180, designated strain EMFR9. Based on mRNA expression levels in the parent and mutant in response to furfural challenge, genes encoding 12 oxidoreductases were found to vary by more than twofold (eight were higher in EMFR9; four were higher in the parent). All 12 genes were cloned. When expressed from plasmids, none of the eight genes in the first group increased furfural tolerance in the parent (LY180). Expression of three of the silenced genes (yqhD,dkgA, andyqfA) in EMFR9 was found to decrease furfural tolerance compared to that in the parent. Purified enzymes encoded byyqhDanddkgAwere shown to have NADPH-dependent furfural reductase activity. Both exhibited lowKmvalues for NADPH (8 μM and 23 μM, respectively), similar to those of biosynthetic reactions. Furfural reductase activity was not associated withyqfA. DeletingyqhDanddkgAin the parent (LY180) increased furfural tolerance, but not to the same extent observed in the mutant EMFR9. Together, these results suggest that the process of reducing furfural by using an enzyme with a lowKmfor NADPH rather than a direct inhibitory action is the primary cause for growth inhibition by low concentrations of furfural.
Recovery Efficiency and Limit of Detection of Aerosolized
Bacillus anthracis
Sterne from Environmental Surface Samples
Authors: Estill Cheryl Fairfield , Baron Paul A. , Beard Jeremy K. , Hein Misty J. , Larsen Lloyd D. , Rose Laura , Schaefer Frank W. , Noble-Wang Judith , Hodges Lisa , Lindquist H. D. Alan , Deye Gregory J. , Arduino Matthew J.
Published: May 2009

After the 2001 anthrax incidents, surface sampling techniques for biological agents were found to be inadequately validated, especially at low surface loadings. We aerosolized
Bacillus anthracis
Sterne spores within a chamber to achieve very low surface loading (ca. 3, 30, and 200 CFU per 100 cm
2
). Steel and carpet coupons seeded in the chamber were sampled with swab (103 cm
2
) or wipe or vacuum (929 cm
2
) surface sampling methods and analyzed at three laboratories. Agar settle plates (60 cm
2
) were the reference for determining recovery efficiency (RE). The minimum estimated surface concentrations to achieve a 95% response rate based on probit regression were 190, 15, and 44 CFU/100 cm
2
for sampling steel surfaces and 40, 9.2, and 28 CFU/100 cm
2
for sampling carpet surfaces with swab, wipe, and vacuum methods, respectively; however, these results should be cautiously interpreted because of high observed variability. Mean REs at the highest surface loading were 5.0%, 18%, and 3.7% on steel and 12%, 23%, and 4.7% on carpet for the swab, wipe, and vacuum methods, respectively. Precision (coefficient of variation) was poor at the lower surface concentrations but improved with increasing surface concentration. The best precision was obtained with wipe samples on carpet, achieving 38% at the highest surface concentration. The wipe sampling method detected
B. anthracis
at lower estimated surface concentrations and had higher RE and better precision than the other methods. These results may guide investigators to more meaningfully conduct environmental sampling, quantify contamination levels, and conduct risk assessment for humans.
Transcriptomic Response of
Lactococcus lactis
in Mixed Culture with
Staphylococcus aureus
Authors: Nouaille Sébastien , Even Sergine , Charlier Cathy , Le Loir Yves , Cocaign-Bousquet Muriel , Loubière Pascal
Published: May 2009

The mechanisms of interaction between
Lactococcus lactis
and the food pathogen
Staphylococcus aureus
are of crucial importance, as one major role of lactic acid bacteria (LAB) in fermented foods is to inhibit undesirable and pathogenic flora. It was never questioned if the presence of a pathogen can actively modify the gene expression patterns of LAB in a shared environment. In this study, transcriptome and biochemical analyses were combined to assess the dynamic response of
L. lactis
in a mixed culture with
S. aureus
. The presence of
S. aureus
hardly affected the growth of
L. lactis
but dramatically modified its gene expression profile. The main effect was related to earlier carbon limitation and a concomitantly lower growth rate in the mixed culture due to the consumption of glucose by both species. More specific responses involved diverse cellular functions. Genes associated with amino acid metabolism, ion transport, oxygen response, menaquinone metabolism, and cell surface and phage expression were differentially expressed in the mixed culture. This study led to new insights into possible mechanisms of interaction between
L. lactis
and
S. aureus
. Moreover, new and unexpected effects of
L. lactis
on the virulence of
S. aureus
were discovered, as described elsewhere (S. Even, C. Charlier, S. Nouaille, N. L. Ben Zakour, M. Cretenet, F. J. Cousin, M. Gautier, M. Cocaign-Bousquet, P. Loubière, and Y. Le Loir, Appl. Environ. Microbiol. 75:4459-4472, 2009).
Dominant Negative Autoregulation Limits Steady-State Repression Levels in Gene Networks
Authors: Semsey Szabolcs , Krishna Sandeep , Erdőssy János , Horváth Péter , Orosz László , Sneppen Kim , Adhya Sankar
Published: May 2009

Many transcription factors repress transcription of their own genes. Negative autoregulation has been shown to reduce cell-cell variation in regulatory protein levels and speed up the response time in gene networks. In this work we examined transcription regulation of the
galS
gene and the function of its product, the GalS protein. We observed a unique operator preference of the GalS protein characterized by dominant negative autoregulation. We show that this pattern of regulation limits the repression level of the target genes in steady states. We suggest that transcription factors with dominant negative autoregulation are designed for regulating gene expression during environmental transitions.
Wall Teichoic Acid Protects
Staphylococcus aureus
against Antimicrobial Fatty Acids from Human Skin
Authors: Kohler Thomas , Weidenmaier Christopher , Peschel Andreas
Published: May 2009

Skin-colonizing gram-positive bacteria produce wall teichoic acids (WTAs) or related glycopolymers for unclear reasons. Using a WTA-deficient
Staphylococcus aureus
mutant, we demonstrated that WTA confers resistance to antimicrobial fatty acids from human sebaceous glands by preventing fatty acid binding. Thus, WTA is probably important for bacterial skin colonization.
Correct Timing ofdnaATranscription and Initiation of DNA Replication RequirestransTranslation
Authors: Cheng Lin , Keiler Kenneth C.
Published: May 2009

Thetranstranslation pathway for protein tagging and ribosome release has been found in all bacteria and is required for proliferation and differentiation in many systems.Caulobacter crescentusmutants that lack thetranstranslation pathway have a defect in the cell cycle and do not initiate DNA replication at the correct time. To determine the molecular basis for this phenotype, effects on events known to be important for initiation of DNA replication were investigated. In the absence oftranstranslation, transcription from thednaApromoter and an origin-proximal promoter involved in replication initiation is delayed. Characterization of thednaApromoter revealed twocis-acting elements that have dramatic effects ondnaAgene expression. A 5′ leader sequence indnaAmRNA represses gene expression by >15-fold but does not affect the timing ofdnaAexpression. The secondcis-acting element, a sequence upstream of the −35 region, affects both the amount ofdnaAtranscription and the timing of transcription in response totranstranslation. Mutations in this promoter element eliminate the transcription delay and partially suppress the DNA replication phenotype in mutants lackingtranstranslation activity. These results suggest that thetranstranslation capacity of the cell is sensed through thednaApromoter to control the timing of DNA replication initiation.
Effects of KCNE2 on HCN isoforms: distinct modulation of membrane expression and single channel properties
Authors: Brandt Mathias C. , Endres-Becker Jeannette , Zagidullin Naufal , Motloch Lukas J. , Er Fikret , Rottlaender Dennis , Michels Guido , Herzig Stefan , Hoppe Uta C.
Published: May 2009

Hyperpolarization-activated cation (HCN) channels give rise to an inward current with similar but not identical characteristics compared with the pacemaker current ( If), suggesting that HCN channel function is modulated by regulatory β-subunits in native tissue. KCNE2 has been proposed to serve as a β-subunit of HCN channels; however, available data remain contradictory. To further clarify this situation, we therefore analyzed the effect of KCNE2 on whole cell currents, single channel properties, and membrane protein expression of all cardiac HCN isoforms in the CHO cell system. On the whole cell level, current densities of all HCN isoforms were significantly increased by KCNE2 without altering voltage dependence or current reversal. While these results correlated well with the KCNE2-mediated 2.2-fold and 1.6-fold increases of membrane protein levels of HCN2 and HCN4, respectively, no effect of KCNE2 on HCN1 expression was obtained. All HCN subtypes displayed faster activation kinetics upon coexpression with KCNE2. Most importantly, for the first time, we demonstrated modulation of single channel function by KCNE2, thus supporting direct functional interaction with HCN subunits. In the presence of KCNE2, the single channel amplitudes and conductance of HCN1, HCN2, and HCN4 were significantly increased versus control recordings. Mean open time was significantly increased in cells coexpressing HCN2 + KCNE2, whereas it was unaffected in HCN1 + KCNE2 cotransfected cells and reduced in HCN4 + KCNE2 cotransfected cells compared with the respective HCN subunits alone. Thus, we demonstrate KCNE2-mediated distinct effects on HCN membrane expression and direct functional modulation of HCN isoforms, further supporting that KCNE2 surves as a regulatory β-subunit of HCN channels.
Relaxin alters cardiac myofilament function through a PKC-dependent pathway
Authors: Shaw Erynn E. , Wood Philip , Kulpa Justyna , Yang Feng Hua , Summerlee Alastair J. , Pyle W. Glen
Published: May 2009

The pregnancy hormone relaxin (RLX) is a powerful cardiostimulatory peptide. Despite its well-characterized effects on the heart, the intracellular mechanisms responsible for RLX's positive inotropic effects are unknown. Cardiac myofilaments are the central contractile elements of the heart, and changes in the phosphorylation status of myofilament proteins are known to mediate changes in function. The first objective of this study was to determine whether RLX stimulates myofilament activation and alters the phosphorylation of one or more myofilament proteins. RLX works through a variety of intracellular signaling cascades in different tissue types. Protein kinases A (PKA) and C (PKC) are two common molecules implicated in RLX signaling and are known to affect myofilament function. Thus the second objective of this study was to determine whether RLX mediates its myocardial effects through PKA or PKC activation. Murine myocardium was treated with recombinant H2-RLX, and cardiac myofilaments were isolated. RLX increased cardiac myofilament force development at physiological levels of intracellular Ca2+ without altering myofilament ATP consumption. Myosin binding protein C, troponin T, and troponin I phosphorylation levels were increased with RLX treatment. Immunoblot analysis revealed an increase in myofilament-associated PKC-δ, decreases in PKC-α and -βII, but no effect on PKC-ε. Inhibition of PKC with chelerythrine chloride or PKC-δ with rottlerin prevented the RLX-dependent changes in myofilament function and protein phosphorylation. PKA antagonism with H-89 had no effect on the myofilament effects of RLX. This study is the first to show that RLX-dependent changes in myofilament-associated PKC alters myofilament activation in a manner consistent with its cardiostimulatory effects.
Reduction of electrical coupling between microvascular endothelial cells by NO depends on connexin37
Authors: McKinnon Rebecca L. , Bolon Michael L. , Wang Hong-Xing , Swarbreck Scott , Kidder Gerald M. , Simon Alexander M. , Tyml Karel
Published: May 2009

We have previously shown that increased nitric oxide (NO) production in sepsis impairs arteriolar-conducted vasoconstriction cGMP independently and that the gap junction protein connexin (Cx) 37 is required for this conducted response. In the present study, we hypothesized that NO impairs interendothelial electrical coupling in sepsis by targeting Cx37. We examined the effect of exogenous NO on coupling in monolayers of cultured microvascular endothelial cells derived from the hindlimb skeletal muscle of wild-type (WT), Cx37 null, Cx40 null, and Cx43G60S (nonfunctional mutant) mice. To assess coupling, we measured the spread of electrical current injected in the monolayer and calculated the monolayer intercellular resistance (inverse measure of coupling). The NO donor 2,2′-(hydroxynitrosohydrazino) bis-ethanamine (DETA) rapidly and reversibly reduced coupling in cells from WT mice, cGMP independently. NO scavenger HbO2 did not affect baseline coupling, but it eliminated DETA-induced reduction in coupling. Reduced coupling in response to DETA was also seen in cells from Cx40 null and Cx43G60S mice, but not in cells from Cx37 null mice. DETA did not alter the expression of Cx37, Cx40, and Cx43 in WT cells analyzed by immunoblotting and immunofluorescence. Furthermore, neither the peroxynitrite scavenger 5,10,15,20-tetrakis(4-sulfonatophenyl)porphyrinato iron (III), superoxide scavenger Mn(III)tetrakis(4-benzoic acid)porphyrin chloride, nor preloading of WT cells with the antioxidant ascorbate affected this reduction. We conclude that NO-induced reduction of electrical coupling between microvascular endothelial cells depends on Cx37 and propose that NO in sepsis impairs arteriolar-conducted vasoconstriction by targeting Cx37 within the arteriolar wall.
Electron‐Collision‐Induced Dissociative Ionization Cross Sections for Silane
Authors: Pal Satyendra , Kumar Neeraj , Anshu
Published: May 2009

Secondary electron energy and angle dependent differential cross sections for the production of cations (n = 0–3), and H+ resulting from dissociative ionization of SiH4by electron collision have been evaluated at fixed incident electron energies of 100 and 200 eV. The semiempirical formulation of Jain and Khare which requires the oscillator strength data as a major input has been employed. In the absence of experimental data for differential cross sections, the corresponding derived integral partial and total ionization cross sections in the energy range varying from ionization threshold to 1000 eV revealed a satisfactory agreement with the available experimental and theoretical data. We have also evaluated the ionization rate coefficients on the basis of calculated partial ionization cross sections and Maxwell‐Boltzmann energy distributions.
Immunoneutralization of TGFβ1 Improves Skeletal Muscle Regeneration: Effects on Myoblast Differentiation and Glycosaminoglycan Content
Authors: Zimowska M. , Duchesnay A. , Dragun P. , Oberbek A. , Moraczewski J. , Martelly I.
Published: May 2009

When injured by crushing, the repair of the slow-twitch soleus rat muscle, unlike the fast-twitch EDL, is associated with fibrosis. As TGFβ1, whose activity can be controlled by glycosaminoglycans (GAG), plays a major role in fibrosis, we hypothesized that levels of TGFβ1 and GAG contents could account for this differential quality of regeneration. Here we show that the regeneration of the soleus was accompanied by elevated and more sustained TGFβ1 level than in the EDL. Neutralization of TGFβ1 effects by antibodies to TGFβ1 or its receptor TGFβ-R1 improved muscle repair, especially of the soleus muscle, increased in vitro growth of myoblasts, and accelerated their differentiation. These processes were accompanied by alterations of GAG contents. These results indicate that the control of TGFβ1 activity is important to improve regeneration of injured muscle and accelerate myoblast differentiation, in part through changes in GAG composition of muscle cell environment.
Adaptive Step‐Size Control in Simulation of Diffusive CVD Processes
Authors: Geiser Jürgen , Fleck Christian
Published: May 2009

We present control strategies of a diffusion process for chemical vapor deposition for metallic bipolar plates. In the models, we discuss the application of different models to simulate the plasma‐transport of chemical reactants in the gas‐chamber. The contribution are an optimal control problem based on a PID control to obtain a homogeneous layering. We have taken into account one‐ and two‐dimensional problems that are given with constraints and control functions. A finite‐element formulation with adaptive feedback control for time‐step selection has been developed for the diffusion process. The optimization is presented with efficient algorithms. Numerical experiments are discussed with respect to the diffusion processes of the macroscopic model.
Mathematical Solutions for Solving Periodic Railway Transportation
Authors: Salido Miguel A. , Barber Federico
Published: May 2009

Train scheduling has been a significant issue in the railway industry. Over
the last few years, numerous approaches and tools have been developed to
compute railway scheduling. In this paper, we present a set of heuristics
for a constraint‐based train scheduling tool, which is a project in collaboration
with the National Network of Spanish Railways (RENFE), Spain.
We formulate train scheduling as constraint optimization problems. Three
heuristics are developed to speed up and direct the search toward suboptimal
solutions in periodic train scheduling problems. The feasibility of
our problem‐oriented heuristics is confirmed with experimentation using
real‐life data. The results show that these techniques enable MIP solvers
such as LINGO and ILOG Concert Technology (CPLEX) to terminate
earlier with good solutions.
Deoxycholate, an Endogenous Cytotoxin/Genotoxin, Induces the Autophagic Stress-Survival Pathway: Implications for Colon Carcinogenesis
Authors: Payne Claire M. , Crowley-Skillicorn Cheray , Holubec Hana , Dvorak Katerina , Bernstein Carol , Moyer Mary Pat , Garewal Harinder , Bernstein Harris
Published: May 2009

We report that deoxycholate (DOC), a hydrophobic bile acid associated with a high-fat diet, activates the autophagic pathway in non-cancer colon epithelial cells (NCM-460), and that this activation contributes to cell survival. The DOC-induced increase in autophagy was documented by an increase in autophagic vacuoles (detected using transmission electron microscopy, increased levels of LC3-I and LC3-II (western blotting), an increase in acidic vesicles (fluorescence spectroscopy of monodansycadaverine and lysotracker red probes), and increased expression of the autophagic protein, beclin-1 (immunohistochemistry/western blotting). The DOC-induced increase in beclin-1 expression was ROS-dependent. Rapamycin (activator of autophagy) pre-treatment of NCM-460 cells significantly (P<.05) decreased, and 3-MA (inhibitor of autophagy) significantly (P<.05) increased the cell loss caused by DOC treatment, alone. Rapamycin pre-treatment of the apoptosis-resistant colon cancer cell line, HCT-116RC (developed in our laboratory), resulted in a significant decrease in DOC-induced cell death. BafilomycinA1and hydroxychloroquine (inhibitors of the autophagic process) increased the DOC-induced percentage of apoptotic cells in HCT-116RC cells. It was concluded that the activation of autophagy by DOC has important implications for colon carcinogenesis and for the treatment of colon cancer in conjunction with commonly used chemotherapeutic agents.
The Efficiency of Variance Reduction in Manufacturing and Service Systems: The Comparison of the Control Variates and Stratified Sampling
Authors: Eraslan Ergün , Dengiz Berna
Published: May 2009

There has been a great interest in the use of variance reduction techniques (VRTs) in simulation output analysis for the purpose of improving accuracy when the performance measurements of complex production and service systems are estimated. Therefore, a simulation output analysis to improve the accuracy and reliability of the output is required. The performance measurements are required to have a narrow and strong confidence interval. For a given confidence level, a smaller confidence interval is supposed to be better than the larger one. The wide of confidence interval, determined by the half length, will depend on the variance. Generally, increased replication of the simulation model appears to have been the easiest way to reduce variance but this increases the simulation costs in complex‐structured and large‐sized manufacturing and service systems. Thus, VRTs are used in experiments to avoid computational cost of decision‐making processes for more precise results. In this study, the effect of Control Variates (CVs) and Stratified Sampling (SS) techniques in reducing variance of the performance measurements of M/M/1 and GI/G/1 queue models is investigated considering four probability distributions utilizing randomly generated parameters for arrival and service processes.
Flat Array Antennas for Ku-Band Mobile Satellite Terminals
Authors: Vincenti Gatti Roberto , Marcaccioli Luca , Sbarra Elisa , Sorrentino Roberto
Published: May 2009

This work presents the advances in the development of two innovative flat array antennas for Ku-band mobile satellite terminals. The first antenna is specifically conceived for double-deck trains to allow a bi-directional high data rate satellite link. The available circular surface (diameter 80 cm) integrates both a transmitting and a receiving section, operating in orthogonal linear polarizations. The TX frequency range is fully covered while the RX bandwidth is around 1 GHz arbitrarily allocated on the DVB range depending on requirements. The beam is steered in elevation through a phased array architecture not employing costly phase shifters, while the steering in azimuth is mechanical. Active BFNs allow excellent performance in terms of EIRP and G/T, maintaining extremely low profile. High antenna efficiency and low fabrication cost are ensured by the employment of innovative SIW (Substrate Integrated Waveguide) structures. The second antenna, receiving-only, is designed for radio/video streaming services in mobile environment. Full DVB coverage is achieved thanks to cavity-backed patches operating in double linear polarization. Two independent broadband active BFNs allow simultaneous reception of both polarizations with full tracking capabilities and a squintless beam steering from to in elevation. A minimum gain of 20 dBi and G/T > dB/ are achieved, while maintaining extremely compact size and flat profile. In the design of both antennas fabrication cost is considered as a driving factor, yet providing high performance with a flat profile and thus resulting in a great commercial potentiality.
Rapamycin Prevents Early Onset of Tumorigenesis in an Oral-Specific K-ras and p53 Two-Hit Carcinogenesis Model
Authors: Raimondi Ana R. , Molinolo Alfredo , Gutkind J. Silvio
Published: May 2009

Head and neck squamous cell carcinomas (HNSCC), the majority of which occur in the oral cavity, remain a significant cause of morbidity and mortality worldwide. A major limitation in HNSCC research has been the paucity of animal models to test the validity of current genetic paradigms of tumorigenesis and to explore the effectiveness of new treatment modalities and chemopreventive strategies. Here, we have developed an inducible oral-specific animal tumor model system, which consists in the expression of a tamoxifen-inducible Cre recombinase (CreERtam) under the control of the cytokeratin 14 (K14) promoter (K14-CreERtam) and mice in which the endogenous K-ras locus is targeted (LSL-K-rasG12D), thereby causing the expression of endogenous levels of oncogenic K-rasG12D following removal of a stop element. Surprisingly, whereas K14-CreERtam can also target the skin, K14-CreERtam/LSL-K-rasG12D mice developed papillomas exclusively in the oral mucosa within 1 month after tamoxifen treatment. These lesions were highly proliferative but never progressed to carcinoma. However, when crossed with p53 conditional knockout (p53flox/flox) mice, mice developed SCCs exclusively on the tongue as early as 2 weeks after tamoxifen induction, concomitant with a remarkable activation of the mammalian target of rapamycin (mTOR) signaling pathway. The availability of this ras and p53 two-hit animal model system recapitulating HNSCC progression may provide a suitable platform for exploring novel molecular targeted approaches for the treatment of this devastating disease. Indeed, we show here that mTOR inhibition by the use of rapamycin is sufficient to halt tumor progression in this genetically defined oral cancer model system, thereby prolonging animal survival. [Cancer Res 2009;69(10):4159–66]
Targeting DNA Repair in Chronic Lymphocytic Leukemia Cells with a Novel Acyclic Nucleotide Analogue, GS-9219
Authors: Tsai Cheng-Yu , Ray Adrian S. , Tumas Daniel B. , Keating Michael J. , Reiser Hans , Plunkett William
Published: May 2009

Purpose: GS-9219 is a cell-permeable prodrug of the acyclic nucleotide analogue 9-(2-phosphonylmethoxyethyl)guanine (PMEG); the incorporation of the active metabolite PMEG diphosphate (PMEGpp) into DNA results in DNA chain termination due to the lack of a 3′-hydroxyl moiety. We hypothesized that the incorporation of PMEGpp into DNA during repair resynthesis would result in the inhibition of DNA repair and the accumulation of DNA breaks in chronic lymphocytic leukemia (CLL) cells that would activate signaling pathways to cell death.

Experimental Design: To test this hypothesis, CLL cells were irradiated with UV light to stimulate nucleotide excision repair pathways, enabling the incorporation of PMEGpp into DNA. The combination effects of GS-9219 and DNA-damaging agents and the signaling mechanisms activated in response to DNA repair inhibition by GS-9219, as well as changes in CLL cell viability, were investigated.

Results: PMEGpp was incorporated into DNA in CLL cells when nucleotide excision repair was activated by UV. Following PMEGpp incorporation, DNA repair was inhibited, which led to the accumulation of DNA strand breaks. The presence of DNA strand breaks activated the phosphatidylinositol 3-kinase–like protein kinase family members ataxia-telangiectasia mutated and DNA-dependent protein kinase. P53 was phosphorylated and stabilized in response to the inhibition of DNA repair. P53 targeted proteins, Puma and Bax, were up-regulated and activated. The combination of GS-9219 and DNA-damaging agents resulted in more cell death than the sum of the single agents alone.

Conclusion: GS-9219 inhibits DNA repair in CLL cells, an action that stimulates signaling pathways for apoptosis induction.
Histone Deacetylase Inhibitor Induction of P-Glycoprotein Transcription Requires Both Histone Deacetylase 1 Dissociation and Recruitment of CAAT/Enhancer Binding Protein β and pCAF to the Promoter Region
Authors: Kim Su-Nam , Kim Nam Hyun , Lee Woojung , Seo Dong-Wan , Kim Yong Kee
Published: May 2009

Although histone deacetylase (HDAC) inhibitors are appreciated as a promising class of anticancer drugs, recent reports show that P-glycoprotein (P-gp) is induced by HDAC inhibitor treatment in cancer cells, resulting in multidrug resistance of cancer cells to other chemotherapeutic agents. In this study, we investigated the molecular mechanism of HDAC inhibitor induction of P-gp expression. HDAC inhibitor treatment causes cell type–specific induction of P-gp expression without changes in the CpG methylation status of the promoter region. In addition, our data show that HDAC inhibitor does not alter the DNA binding activity of Sp1 but facilitates both the recruitment of a coactivator complex that includes CAAT/enhancer binding protein β and pCAF and the dissociation of the repressive complex, HDAC1, to the Sp1 binding region. Subsequently, the hyperacetylated histone H3 becomes enriched in the promoter region, leading to RNA polymerase II recruitment to activate P-gp gene transcription. Furthermore, specific down-regulation of HDAC1, but not HDAC2, by RNA silencing was enough to induce P-gp expression in HeLa cells, strongly supporting the essential role of HDAC1 in HDAC inhibitor induction of P-gp. Concomitantly, cell type–specific induction of P-gp expression seems to be dependent on phosphatidylinositol 3-kinase activity. Taken together, our findings show that HDAC inhibitor treatment leads to an increase in P-gp expression through dynamic changes in chromatin structure and transcription factor association within the promoter region. (Mol Cancer Res 2009;7(5):735–44)
Lack of Correlation Between Noninvasive Stress Tests and Invasive Coronary Vasomotor Dysfunction in Patients With Nonobstructive Coronary Artery Disease
Authors: Cassar Andrew , Chareonthaitawee Panithaya , Rihal Charanjit S. , Prasad Abhiram , Lennon Ryan J. , Lerman Lilach O. , Lerman Amir
Published: May 2009

Background—

Despite a nonobstructive coronary angiogram, many patients may still have an abnormal coronary vasomotor response to provocation and to myocardial demand during stress. The ability of noninvasive stress tests to predict coronary vasomotor dysfunction in patients with nonobstructive coronary artery disease is unknown.

Methods and Results—

All patients with nonobstructive coronary artery disease who had invasive coronary vasomotor assessment and a noninvasive stress test (exercise ECG, stress echocardiography, or stress nuclear imaging) within 6 months of the cardiac catheterization with provocation at our institution were identified (n=376). Coronary vasomotor dysfunction was defined as a percentage increase in coronary blood flow of ≤50% to intracoronary acetylcholine (endothelium-dependent dysfunction) and/or a coronary flow reserve ratio of ≤2.5 to intracoronary adenosine (endothelium-independent dysfunction). We determined the sensitivity and specificity of various noninvasive stress tests to predict coronary vasomotor dysfunction in these patients. On invasive testing, 233 patients (63%) had coronary vasomotor dysfunction, of which 187 patients (51%) had endothelium-dependent dysfunction, 109 patients (29%) had endothelium-independent dysfunction, and 63 patients (17%) had both. On noninvasive stress testing, 157 (42%) had a positive imaging study and 56 (15%) a positive ECG stress test. The noninvasive stress tests had limited diagnostic accuracy for predicting coronary vasomotor dysfunction (41% sensitivity [95% CI, 34 to 47] and 57% specificity [95% CI, 49 to 66]), endothelium-dependent dysfunction (41% sensitivity [95% CI, 34 to 49] and 58% specificity [95% CI, 50 to 65]), or endothelium-independent dysfunction (46% sensitivity [95% CI, 37 to 56] and 61% specificity [95% CI, 54 to 67]). The exercise ECG test was more specific but less sensitive than the imaging tests.

Conclusion—

This study suggests that a negative noninvasive stress test does not rule out coronary vasomotor dysfunction in symptomatic patients with nonobstructive coronary artery disease. This underscores the need for invasive assessment or novel more sensitive noninvasive imaging for these patients.
Conceptualizing Occupational Prestige: An Empirical Case Study from Iran
Authors: Abdollahyan Hamid , Nayebi Hooshang
Published: May 2009

This paper attempts to present a theoretically justified methodological
concept of occupational prestige as one of the common indexes of social
stratification. In order to do that, we first critically review Davis and
Moor's theory of social stratification and argue that social stratification,
defined as “systematically unequal distribution of symbolic and material
rewards among social positions”, is conceptually distinct from Marx's
conception of social class. Davis and Moor's concept of social
stratification has a functional necessity in any complex society, in the
sense that no position is expected to remain vacant, and that qualified
people are conditioned into positions. The determinants for ranking
positions in such a context are the degree of specialty required to perform
duties related to positions, or the level of the authority related to each
position. Secondly, we claim that the prestige structure of the social
positions, which is the stable symbolic dimension of stratification and is
correlated closely with its material dimension, is indeed the representative
of the whole social stratification and that the structure of occupational
prestige is the index of the former. In conclusion, we verify our claims by
providing empirical evidence that has resulted from our own research in Iran
or that comes from similar research carried out by other scholars across the
world.
Propensity for Violence Among Homeless and Runaway Adolescents
Authors: Crawford Devan M. , Whitbeck Les B. , Hoyt Dan R.
Published: May 2009

Little is known about the prevalence of violent behaviors among homeless and runaway adolescents or the specific behavioral factors that influence violent behaviors across time. In this longitudinal study of 300 homeless and runaway adolescents aged 16 to 19 at baseline, the authors use event history analysis to assess the factors associated with acts of violence over 3 years, controlling for individual propensities and time-varying behaviors. Results indicate that females, nonminorities, and nonheterosexuals were less likely to engage in violence across time. Those who met criteria for substance abuse disorders (i.e., alcohol abuse, alcohol dependence, drug abuse) were more likely to engage in violence. A history of caretaker abuse was associated with violent behaviors, as were street survival strategies such as selling drugs, participating in gang activity, and associating with deviant peers. Simply having spent time directly on the streets at any specific time point also increased the likelihood for violence.
Severe Neuropathy After Diphtheria-Tetanus-Pertussis Vaccination in a Child Carrying a Novel Frame-Shift Mutation in the Small Heat-Shock Protein 27 Gene
Authors: Mandich Paola , Grandis Marina , Varese Alessandra , Geroldi Alessandro , Acquaviva Massimo , Ciotti Paola , Gulli Rossella , Doria-Lamba Laura , Fabrizi Gian Maria , Giribaldi Gaia , Pizzuti Antonio , Schenone Angelo , Bellone Emilia
Published: May 2009

Mutations in small heat-shock protein 27 and small heat-shock protein 22 genes were found in association with Charcot-Marie-Tooth disease type 2 and distal hereditary motor neuropathy. We searched for mutations in small heat-shock protein 27 gene in an Italian family with peripheral neuropathy and intrafamilial phenotypic variability. A novel heterozygous frame-shift mutation c.476_477delCT was found while point mutations in most genes associated with hereditary neuropathies were ruled out. In the proband, who showed a severe early onset peripheral neuropathy, an independent pathogenetic effect on the peripheral nervous system secondary to the tetanus toxoid injection may be supposed. This is the first truncating nonsense mutation in the small heat-shock protein 27 gene identified so far and the clinical, neurophysiologic, and neuropathological findings are discussed.
Depressive Symptoms in Parkinson Disease Correlate With Impaired Global and Specific Cognitive Performance
Authors: Fernandez Hubert H. , See Reiner H. , Gary Matthew F. , Bowers Dawn , Rodriguez Ramon L. , Jacobson Charles , Okun Michael S.
Published: May 2009

Consecutive patients in a Movement Disorders Center with Parkinson disease (PD) were offered to undergo complete neuropsychological testing and to complete the Beck Depression Inventory (BDI), regardless of their cognitive and behavioral status. A total of 82 patients were included in this cross-sectional study and had a mean age of 67.7 years, formal education of 14.8 years, PD duration of 101 months, Unified Parkinson Disease Rating Scale—Motor ‘‘off’’ score of 36.96, Mini-Mental State Examination (MMSE) score of 27.8 (range 19-30), and BDI score of 10.23 (SD 8.65). Beck Depression Inventory scores did not correlate with disease duration or motor scores but inversely correlated with the MMSE scores (r = —0.40; P < .001) and total Dementia Rating Scale (DRS) scores (r = —0.33; P < .01). Using a univariate regression analysis controlling for age, gender, education, and total Unified Parkinson Disease Rating Scales (UPDRS) score, the BDI scores had a significant and unique relationship with MMSE scores. However, when the BDI scores were correlated with specific cognitive domains, only the Boston Naming Test and the Hopkins Verbal Learning Test (HVLT) delayed recall remained significant after Bonferroni correction. Similarly, when comparing the cognitive performance of patients with PD who scored >14 on the BDI versus those who scored <14, only the mean score of the Boston Naming Test was different between the 2 groups. Our study shows that while depressive symptoms correlated with global cognitive performance, naming, verbal memory, and language are the most susceptible cognitive domains affected with depressive symptoms.
Disruption of Normal Cytoskeletal Dynamics May Play a Key Role in the Pathogenesis of Epilepsy
Authors: Gardiner John , Marc Jan
Published: May 2009

Epilepsy, a common disease affecting 1% to 2% of the population, is characterized by seizures, hyperexcitability at synapses, and aberrant extension of neurons following seizures. Much work has been done on the role of synaptic components in the pathogenesis of epilepsy, but relatively little attention has been given to the potential role of the cytoskeleton. The neuronal cytoskeleton consists of microtubules, actin filaments, intermediate filaments, and associated proteins. A number of mutations in both microtubule-associated proteins (MAPs) and actin-binding proteins, as well as altered expression levels of several cytoskeletal proteins, are known to be involved in epilepsy. These changes will affect the dynamics of the neuronal cytoskeleton and therefore are likely to contribute to the pathogenesis of epilepsy through mechanisms such as increased neurotrophic support to neurons and increased sprouting of mossy fibers. These changes may also contribute to hyperexcitability of neurons through an as yet unidentified mechanism.
Oligodendrocytes: Facilitating Axonal Conduction by More Than Myelination
Authors: Yamazaki Yoshihiko , Hozumi Yasukazu , Kaneko Kenya , Fujii Satoshi , Goto Kaoru , Kato Hiroshi
Published: May 2009

Oligodendrocytes have received much attention in relation to neurological and psychiatric disorders. The involvement of oligodendrocytes and their myelin in normal brain functions has been suggested by many lines of evidence. The conduction velocity of action potentials along axons is dramatically increased by myelination, that is, the formation of a passive insulator. There is a growing understanding of the functional roles of ion channels and neurotransmitter receptors on oligodendrocytes, and the activity-dependent facilitative effect of oligodendrocytes on conduction velocity has been demonstrated. In this article, we summarize evidence for the ability of oligodendrocytes to monitor neuronal activity and for the facilitation of axonal conduction by oligodendrocytes by mechanisms other than myelination. We suggest the underlying mechanisms for this facilitation in relation to the morphological dynamics of myelinating processes and discuss the physiological roles of the facilitation in information processing.
National Survey of Psychiatric Mental Health Advanced Practice Nursing: Development, Process, and Finding
Authors: Drew Barbara L. , Delaney Kathleen R.
Published: May 2009

A survey was sent to all Psychiatric Mental Health (PMH) Advanced Practice Registered Nurses (APRNs) who had a registered e-mail address with the American Nurses Credentialing Center, resulting in 1,899 usable surveys. The practice of two groups of APRNs was examined and contrasted: those certified to treat children and adolescents and PMH-APRNs certified only to treat adults. Our findings raise concerns about the numbers of PMH-APRNs treating children. Considering the national demand for mental health professionals prepared to treat children, the specialty must move to increase the number of qualified APRN child providers.
Implicit Measurement of Sexual Associations in Child Sex Abusers
Authors: Brown Anthony S. , Gray Nicola S. , Snowden Robert J.
Published: May 2009

The Implicit Association Test was used to measure cognitive associations between children and sex in men convicted of child-sex offences. It was hypothesized that these cognitions would be different in pedophilic-type offenders (defined by having a victim aged less than 12 years) and hebephilic-type offenders (only victims aged 12 to 15 years) such that only the pedophilic-type offenders would have an implicit association between children and sex. This was confirmed. It was also hypothesized that this association between children and sex in the pedophilic-type offenders would be present irrespective of their denial of offence history. This was also confirmed. These results demonstrate differences in the cognitive associations between children and sex held by subgroups of child-sex abusers, and they help establish the Implicit Association Test as an indirect means to assess cognitive factors related to sexual offences.
Validating for Use and Interpretation
Authors: Morell Linda , Tan Rachael Jin Bee
Published: May 2009

Researchers in the areas of psychology and education strive to understand the intersections among validity, educational measurement, and cognitive theory. Guided by a mixed model conceptual framework, this study investigates how respondents' opinions inform the validation argument. Validity evidence for a science assessment was collected through traditional paper-and-pencil tests, surveys, and think-aloud and exit interviews of fifth- and sixth-grade students. Item response theory analyses supplied technical descriptions of evidence investigating the internal structure. Surveys provided information regarding perceived item difficulty and fairness. Think-aloud and exit interviews provided context and response processes information to clarify and explain issues. This research demonstrates how quantitative and qualitative data can be used in concert to inform the validation process and highlights the use of think-aloud interviews as an explanatory tool.
Comparison of the in vitro and in vivo susceptibilities of Burkholderia mallei to Ceftazidime and Levofloxacin
Authors: Judy Barbara M , Whitlock Gregory C , Torres Alfredo G , Estes D Mark
Published: May 2009

Background

Burkholderia mallei is a zoonotic Gram negative bacterium which primarily infects solipeds but can cause lethal disease in humans if left untreated. The effect of two antibiotics with different modes of action on Burkholderia mallei strain ATCC23344 was investigated by using in vitro and in vivo studies.

Results

Determination of minimal inhibitory concentrations (MICs) in vitro was done by the agar diffusion method and the dilution method. The MICs of levofloxacin and ceftazidime were in the similar range, 2.5 and 5.0 μg/ml, respectively. Intracellular susceptibility of the bacterium to these two antibiotics in J774A.1 mouse macrophages in vitro was also investigated. Macrophages treated with antibiotics demonstrated uptake of the drugs and reduced bacterial loads in vitro. The efficacy of ceftazidime and levofloxacin were studied in BALB/c mice as post-exposure treatment following intranasal B. mallei infection. Intranasal infection with 5 × 105 CFUs of B. mallei resulted in 90% death in non-treated control mice. Antibiotic treatments 10 days post-infection proved to be effective in vivo with all antibiotic treated mice surviving to day 34 post-infection. The antibiotics did not result in complete clearance of the bacterial infection and presence of the bacteria was found in lungs and spleens of the survivors, although bacterial burden recovered from levofloxacin treated animals appeared reduced compared to ceftazidime.

Conclusion

Both antibiotics demonstrated utility for the treatment of glanders, including the ability for intracellular penetration and clearance of organisms in vitro.