bluuebunny/crossref_metadata_2025 huggingface dataset:
Bright and Dark Polar Deposits on Mercury: Evidence for Surface Volatiles
Authors: Neumann Gregory A. , Cavanaugh John F. , Sun Xiaoli , Mazarico Erwan M. , Smith David E. , Zuber Maria T. , Mao Dandan , Paige David A. , Solomon Sean C. , Ernst Carolyn M. , Barnouin Olivier S.
Published: November 2012

Wet Mercury

Radar observations of Mercury's poles in the 1990s revealed regions of high backscatter that were interpreted as indicative of thick deposits of water ice; however, other explanations have also been proposed (see the Perspective by

Lucey

). MESSENGER neutron data reported by

Lawrence
et al.

(p.
292
, published online 29 November) in conjunction with thermal modeling by

Paige
et al.

(p.
300
, published online 29 November) now confirm that the primary component of radar-reflective material at Mercury's north pole is water ice.

Neumann
et al.

(p.
296
, published online 29 November) analyzed surface reflectance measurements from the Mercury Laser Altimeter onboard MESSENGER and found that while some areas of high radar backscatter coincide with optically bright regions, consistent with water ice exposed at the surface, some radar-reflective areas correlate with optically dark regions, indicative of organic sublimation lag deposits overlying the ice. Dark areas that fall outside regions of high radio backscatter suggest that water ice was once more widespread.
Thermal Stability of Volatiles in the North Polar Region of Mercury
Authors: Paige David A. , Siegler Matthew A. , Harmon John K. , Neumann Gregory A. , Mazarico Erwan M. , Smith David E. , Zuber Maria T. , Harju Ellen , Delitsky Mona L. , Solomon Sean C.
Published: November 2012

Wet Mercury

Radar observations of Mercury's poles in the 1990s revealed regions of high backscatter that were interpreted as indicative of thick deposits of water ice; however, other explanations have also been proposed (see the Perspective by

Lucey

). MESSENGER neutron data reported by

Lawrence
et al.

(p.
292
, published online 29 November) in conjunction with thermal modeling by

Paige
et al.

(p.
300
, published online 29 November) now confirm that the primary component of radar-reflective material at Mercury's north pole is water ice.

Neumann
et al.

(p.
296
, published online 29 November) analyzed surface reflectance measurements from the Mercury Laser Altimeter onboard MESSENGER and found that while some areas of high radar backscatter coincide with optically bright regions, consistent with water ice exposed at the surface, some radar-reflective areas correlate with optically dark regions, indicative of organic sublimation lag deposits overlying the ice. Dark areas that fall outside regions of high radio backscatter suggest that water ice was once more widespread.
CTCF Regulates Kaposi's Sarcoma-Associated Herpesvirus Latency Transcription by Nucleosome Displacement and RNA Polymerase Programming
Authors: Kang Hyojeung , Cho Hyosun , Sung Gi-Ho , Lieberman Paul M.
Published: November 2012

CCCTC-binding factor (CTCF) has been implicated in various aspects of viral and host chromatin organization and transcriptional control. We showed previously that CTCF binds to a cluster of three sites in the first intron of the Kaposi's sarcoma-associated herpesvirus (KSHV) multicistronic latency-associated transcript that encodes latency-associated nuclear antigen (LANA), viral cyclin (vCyclin), vFLIP, viral microRNAs, and kaposin. We show here that these CTCF binding sites regulate mRNA production, RNA polymerase II (RNAPII) programming, and nucleosome organization of the KSHV latency transcript control region. We also show that KSHV bacmids lacking these CTCF binding sites have elevated and altered ratios of spliced latency transcripts. CTCF binding site mutations altered RNAPII and RNAPII-accessory factor interactions with the latency control region. CTCF binding sites were required for thein vitrorecruitment of RNAPII to the latency control region, suggesting that direct interactions between CTCF and RNAPII contribute to transcription regulation. Histone modifications in the latency control region were also altered by mutations in the CTCF binding sites. Finally, we show that CTCF binding alters the regular phasing of nucleosomes in the latency gene transcript and intron, suggesting that nucleosome positioning can be an underlying biochemical mechanism of CTCF function. We propose that RNAPII interactions and nucleosome displacement serve as a biochemical basis for programming RNAPII in the KSHV transcriptional control region.
Varicella-Zoster Virus ORF12 Protein Activates the Phosphatidylinositol 3-Kinase/Akt Pathway To Regulate Cell Cycle Progression
Authors: Liu XueQiao , Cohen Jeffrey I.
Published: November 2012

Varicella-zoster virus (VZV) activates the phosphatidylinositol 3-kinase (PI3K)/Akt pathway and alters cell cycle progression, but the viral protein(s) responsible for these activities is unknown. We previously reported that the VZV open reading frame 12 (ORF12) protein triggers phosphorylation of ERK. Here, we demonstrate that the VZV ORF12 protein also activates the PI3K/Akt pathway to regulate cell cycle progression. Transfection of cells with a plasmid expressing the ORF12 protein induced phosphorylation of Akt, which was dependent on PI3K. Infection of cells with wild-type VZV triggered phosphorylation of Akt, while infection with an ORF12 deletion mutant induced less phosphorylated Akt. The activation of Akt by ORF12 protein was associated with its binding to the p85 subunit of PI3K. Infection of cells with wild-type VZV resulted in increased levels of cyclin B1, cyclin D3, and phosphorylated glycogen synthase kinase 3β (GSK-3β), while infection with the ORF12 deletion mutant induced lower levels of these proteins. Wild-type VZV infection reduced the G
1
phase cell population and increased the M phase cell population, while infection with the ORF12 deletion mutant had a reduced effect on the G
1
and M phase populations. Inhibition of Akt activity with LY294002 reduced the G
1
and M phase differences observed in cells infected with wild-type and ORF12 mutant viruses. In conclusion, we have found that the VZV ORF12 protein activates the PI3K/Akt pathway to regulate cell cycle progression. Since VZV replicates in both dividing (e.g., keratinocytes) and nondividing (neurons) cells, the ability of the VZV ORF12 protein to regulate the cell cycle is likely important for VZV replication in various cell types in the body.
Corneal depositions in tyrosinaemia type I during treatment with Nitisinone
Authors: Wisse Robert P L , Wittebol-Post Dienke , Visser Gepke , van der Lelij Allegonda
Published: November 2012

We present a 17-year-old boy, diagnosed with tyrosinaemia type I at an age of 7 months, with new complaints of severe intermittent photophobia and burning eyes. His tyrosinaemia type I is treated with nitisinone and a protein-restricted diet. Dietary compliance is low since he entered puberty. His ocular complaints are attributable to subepithelial corneal deposits, resembling the common corneal phenotype of tyrosinaemia type II. Serum tyrosine levels were markedly elevated. Tyrosinaemia is a metabolic disease of tyrosine metabolism, subdivided into two types. Corneal deposits and photophobia are cardinal features of untreated tyrosinaemia type II, but not of type I. Novel treatment strategies (with nitisinone) for type I tyrosinaemia lead to a phenotype comparable with type II, including these corneal deposits. At follow-up visits his ocular complaints unfortunately remained unchanged, though he states his dietary compliance improved through the years.
Adverse reaction; patent blue turning patient blue
Authors: Joshi Meera , Hart Matthew , Ahmed Farid , McPherson Sandy
Published: November 2012

The authors report a severe anaphylactic reaction to Patent Blue V dye used in sentinel node biopsy for lymphatic mapping during breast cancer surgery to stage the axilla. Patent Blue dye is the most widely used in the UK; however, adverse reactions have been reported with the blue dye previously. This case highlights that reactions may not always be immediately evident and to be vigilant in all patients that have undergone procedures using blue dye. If the patients are not responding appropriately particularly during an anaesthetic, one must always think of a possible adverse reaction to the dye. All surgical patients should give consent for adverse reactions to patent blue dye preoperatively. Alternative agents such as methylene blue are considered.
Ascites as a manifestation of effusive-constrictive pericarditis in an African patient
Authors: Barosa Rita , Marinho Rui Tato , Ramalho Fernando , Velosa José
Published: November 2012

A 34-year-old man from Sao Tome and Principe, Africa, with a history of tuberculosis and alcohol ingestion greater than 100 g/day presented with progressively worsening dyspnoea, right upper quadrant pain and progressively increasing abdominal volume. Physical examination revealed distended jugular veins, tender hepatomegaly, moderate ascites and oedema of lower limbs. MRI revealed collection of pericardial fluid compressing the right ventricle and a thickened pericardium, consistent with an effusive-constrictive pericarditis. Cultures and biopsies were undertaken. Antituberculosis drugs and prednisolone were initiated and drainage of the pericardial collection and pericardiectomy were performed. He recovered with complete remission of signs and symptoms.
Karyotype evolution in the Pinaceae: implication with molecular phylogeny
Authors: Nkongolo K.K. , Mehes-Smith M.
Published: November 2012

The family Pinaceae is made up mostly of diploid species (2n = 24). Systematization of karyotype analysis was developed to make comparison of intra- and interspecific karyotypes among the Pinaceae more accurate and reliable. Considering all parameters, the genera Pseudotsuga and Pseudolarix have the “most derived” (or advanced) and asymmetric karyotypes in the Pinaceae, followed by Larix, Picea, Abies, and Cedrus. The genus Pinus was the “least derived” (or ancestral) of all the genera of the Pinaceae analyzed. Differences in karyotype formulae and asymmetry indices were found among species within the same genera, suggesting that structural changes may have contributed to the diversification of the genus. This review is a detailed analysis of comparative karyotyping based on similar parameters, including numeric data and cytogenetic information. Telomeric sequence repeats and rDNA distribution in the Pinaceae were surveyed. The role of transposition in rDNA chromosome distribution is analyzed. Cytogenetic implications of hybridization between related species are reported. Likewise, the relationships between molecular phylogenetic and karyotype evolution is discussed in light of several reports. Within many genera, chromosomal organization was conserved despite independent molecular divergence and adaptation through the evolutionary history of the species of the Pinaceae.
Characterization of wheat – Secale africanum introgression lines reveals evolutionary aspects of chromosome 1R in rye
Authors: Lei Meng-Ping , Li Guang-Rong , Liu Cheng , Yang Zu-Jun
Published: November 2012

Wild Secale species, Secale africanum Stapf., serve as a valuable source for increasing the diversity of cultivated rye (Secale cereale L.) and provide novel genes for wheat improvement. New wheat – S. africanum chromosome 1Rafr addition, 1Rafr(1D) substitution, 1BL.1RafrS and 1DS.1RafrL translocation, and 1RafrL monotelocentric addition lines were identified by chromosome banding and in situ hybridization. Disease resistance screening revealed that chromosome 1RafrS carries resistance gene(s) to new stripe rust races. Twenty-nine molecular markers were localized on S. africanum chromosome 1Rafr by the wheat – S. africanum introgression lines. Twenty markers can also identically amplify other reported wheat – S. cereale chromosome 1R derivative lines, indicating that there is high conservation between the wild and cultivated Secale chromosome 1R. Nine markers displayed polymorphic amplification between S. africanum and S. cereale chromosome 1Rafr derivatives. The comparison of the nucleotide sequences of these polymorphic markers suggested that gene duplication and sequence divergence may have occurred among Secale species during its evolution and domestication.
EST sequencing and fosmid library construction in a non-model moth,Mamestra brassicae, for comparative mapping
Authors: Kamimura Manabu , Tateishi Ken , Tanaka-Okuyama Makiko , Okabe Takuya , Shibata Fukashi , Sahara Ken , Yasukochi Yuji
Published: November 2012

Genome data are useful for both basic and applied research; however, it is difficult to carry out large-scale genome analyses using species with limited genetic or genomic resources. Here, we describe a cost-effective method to analyze the genome of a non-model species, using the cabbage moth, Mamestra brassicae (Lepidoptera: Noctuidae). First, we conducted expression sequence tag (EST) analysis. In this analysis, we performed PCR-based prescreening of a non-normalized embryonic cDNA library to eliminate already sequenced cDNAs from further sequencing, which significantly increased the percentage of unique genes. Next, we constructed a fosmid library of M. brassicae and isolated 120 clones containing 119 putative single copy genes by PCR-based screening with primer sets designed from the ESTs. Finally, we showed that the isolated fosmid clones could be used as probes for multicolor fluorescence in situ hybridization (FISH) analysis against an M. brassicae chromosome and confirmed conserved gene order between M. brassicae and the silkworm, Bombyx mori. Thus, we developed new genomic resources for comparative genome analysis in M. brassicae using robust and relatively low cost methods that can be applied to any non-model organism.
Discovery of a new source of resistance to Fusarium oxysporum, cause of Fusarium wilt in Allium fistulosum, located on chromosome 2 of Allium cepa Aggregatum group
Authors: Vu Hoa Q. , El-Sayed Magdi A. , Ito Shin-Ichi , Yamauchi Naoki , Shigyo Masayoshi
Published: November 2012

This study was carried out to evaluate the antifungal effect of Allium cepa Aggregatum group (shallot) metabolites on Fusarium oxysporum and to determine the shallot chromosome(s) related to Fusarium wilt resistance using a complete set of eight Allium fistulosum – shallot monosomic addition lines. The antifungal effects of hexane, butanol, and water extraction fractions from bulbs of shallot on 35 isolates of F. oxysporum were examined using the disc diffusion method. Only hexane and butanol fractions showed high antifungal activity. Shallot showed no symptom of disease after inoculation with F. oxysporum f. sp. cepae. The phenolic content of the roots and the saponin content of root exudates of inoculated shallot increased to much higher levels than those of the control at 3 days after inoculation. Application of freeze-dried shallot root exudates to seeds of A. fistulosum soaked in a spore suspension of F. oxysporum resulted in protection of seedlings against infection. Among eight monosomic addition lines and A. fistulosum, FF+2A showed the highest resistance to Fusarium wilt. This monosomic addition line also showed a specific saponin band derived from shallot on the thin layer chromatography profile of saponins in the eight monosomic addition lines. The chromosome 2A of shallot might possess some of the genes related to Fusarium wilt resistance.
In situ hybridization analysis of gibbon chromosomes suggests that amplification of alpha satellite DNA in the telomere region is confined to two of the four genera
Authors: Baicharoen Sudarath , Arsaithamkul Visit , Hirai Yuriko , Hara Toru , Koga Akihiko , Hirai Hirohisa
Published: November 2012

The siamang (Symphalangus syndactylus), a species of the family Hylobatidae (gibbons), carries large blocks of constitutive heterochromatin in the telomere region of chromosomes. We recently found that alpha satellite DNA constitutes these heterochromatin blocks as a main component. Alpha satellite DNA, tandem repeat sequences of 171-bp repeat units, is a major component of centromeres in primates. In addition to the siamang, the white-cheeked gibbon (Nomascus leucogenys) was previously found to carry the alpha satellite DNA in the telomere region, although not as large a scale as the siamang. Gibbons comprise four genera: Hoolock, Hylobates, Nomascus, and Symphalangus. Here, we report that the amplification of alpha satellite DNA in the telomere region is probably confined to two genera: Nomascus and Symphalangus. We examined one species of Hoolock and four species of Hylobates and obtained evidence against such an amplification event in these species. The phylogenetic relationship of the four gibbon genera remains unclear. One simple explanation for the current distribution of the telomere region alpha satellite DNA would be that Nomascus and Symphalangus are relatively closely related and the amplification occurred in their common ancestor.
HOW NETWORK MANAGERS CONTRIBUTE TO INNOVATION NETWORK PERFORMANCE
Authors: LANDSPERGER JOHANNES , SPIETH PATRICK , HEIDENREICH SVEN
Published: November 2012

Innovation networks that aim at the joint development of products, services or processes represent a particular form of inter-organizational business networks. In order to yield useful results from these collaborations, networks need to be managed thoroughly. By appointing a dedicated network manager to administrate, coordinate, and regulate, the management of tasks is bundled and centralized within a single entity. However, to the best knowledge of the authors, no empirical research has yet been conducted, investigating the impact of a network manager's availability, relevance, and influence on network performance. Using the interaction-oriented network approach as conceptual foundation, we analyze network managers' direct and indirect influence on the network's relational and goal achievement performance. Our results suggest that a network manager enhances innovation network's core management functions, which in turn improve the relational performance (RP). Moreover, RP was found to significantly drive the goal achievement performance (GAP).
BENEFITS AND BARRIERS OF CROWDSOURCING IN B2B FIRMS: GENERATING IDEAS WITH INTERNAL AND EXTERNAL CROWDS
Authors: SIMULA HENRI , VUORI MERVI
Published: November 2012

In recent years crowdsourcing has increased in popularity as a method for gathering ideas for new innovations and providing solutions to existing problems. This means that firms apply the wisdom of crowds to certain tasks and challenges. Various crowdsourcing initiatives and platforms seem to provide new channels and ways to enable this in practice. The purpose of this paper is to examine how business-to-business (B2B) firms can interact with different groups of contributors in order to receive new ideas, feedback and solutions for improving their products and services. Based on theoretical conceptualization, combined with empirical evidence, we propose a layered framework for approaching crowdsourcing in a B2B context. The empirical results of this paper reveal benefits but also practical challenges to overcome before crowdsourcing can be effectively utilized in the B2B sector.
DISCONTINUITY AND COLLABORATION: THEORY AND EVIDENCE FROM TECHNOLOGICAL PROJECTS
Authors: DAOUDI JAOUAD , BOURGAULT MARIO
Published: November 2012

Project teams today often work in complex collaborative and extended settings, especially when multinational firms or international projects are involved. Studies on projects have attempted to identify and measure the factors that influence collaboration. Many models have been proposed, reflecting the rising importance of this research area. However, few authors have explored the contribution of discontinuity to effective collaboration. This article presents a theoretical overview of discontinuity and collaboration practices in technology industries. The empirical results of a study of technological projects are then presented. The results support the contribution of discontinuity to effective collaboration. A more surprising result suggests that different forms of discontinuity contribute differently to collaboration and that cultural discontinuity has a negligible impact on collaboration.
Activation of c-SRC underlies the differential effects of ouabain and digoxin on Ca2+ signaling in arterial smooth muscle cells
Authors: Zulian Alessandra , Linde Cristina I. , Pulina Maria V. , Baryshnikov Sergey G. , Papparella Italia , Hamlyn John M. , Golovina Vera A.
Published: November 2012

Cardiotonic steroids (CTS) of the strophanthus and digitalis families have opposing effects on long-term blood pressure (BP). This implies hitherto unrecognized divergent signaling pathways for these CTS. Prolonged ouabain treatment upregulates Ca2+ entry via Na+/Ca2+ exchanger-1 (NCX1) and TRPC6 gene-encoded receptor-operated channels in mesenteric artery smooth muscle cells (ASMCs) in vivo and in vitro. Here, we test the effects of digoxin on Ca2+ entry and signaling in ASMC. In contrast to ouabain treatment, the in vivo administration of digoxin (30 μg·kg−1·day−1 for 3 wk) did not raise BP and had no effect on resting cytolic free Ca2+ concentration ([Ca2+]cyt) or phenylephrine-induced Ca2+ signals in isolated ASMCs. Expression of transporters in the α2 Na+ pump-NCX1-TRPC6 Ca2+ signaling pathway was not altered in arteries from digoxin-treated rats. Upregulated α2 Na+ pumps and a phosphorylated form of the c-SRC protein kinase (pY419-Src, ∼4.5-fold) were observed in ASMCs from rats treated with ouabain but not digoxin. Moreover, in primary cultured ASMCs from normal rats, treatment with digoxin (100 nM, 72 h) did not upregulate NCX1 and TRPC6 but blocked the ouabain-induced upregulation of these transporters. Pretreatment of ASMCs with the c-Src inhibitor PP2 (1 μM; 4-amino-5-(4-chlorophenyl)-7-( t-butyl)pyrazolo[3,4- d]pyrimidine) but not its inactive analog eliminated the effect of ouabain on NCX1 and TRPC6 expression and ATP-induced Ca2+ entry. Thus, in contrast to ouabain, the interaction of digoxin with α2 Na+ pumps is unable to activate c-Src phosphorylation and upregulate the downstream NCX1-TRPC6 Ca2+ signaling pathway in ASMCs. The inability of digoxin to upregulate c-Src may underlie its inability to raise long-term BP.
A novel mechanism for gut barrier dysfunction by dietary fat: epithelial disruption by hydrophobic bile acids
Authors: Stenman Lotta K. , Holma Reetta , Eggert Ariane , Korpela Riitta
Published: November 2012

Impairment of gut barrier is associated with a fat-rich diet, but mechanisms are unknown. We have earlier shown that dietary fat modifies fecal bile acids in mice, decreasing the proportion of ursodeoxycholic acid (UDCA) vs. deoxycholic acid (DCA). To clarify the potential role of bile acids in fat-induced barrier dysfunction, we here investigated how physiological concentrations of DCA and UDCA affect barrier function in mouse intestinal tissue. Bile acid experiments were conducted in vitro in Ussing chambers using 4- and 20-kDa FITC-labeled dextrans. Epithelial integrity and inflammation were assayed by histology and Western blot analysis for cyclooxygenase-2. LPS was studied in DCA-induced barrier dysfunction. Finally, we investigated in a 10-wk in vivo feeding trial in mice the barrier-disrupting effect of a diet containing 0.1% DCA. DCA disrupted epithelial integrity dose dependently at 1–3 mM, which correspond to physiological concentrations on a high-fat diet. Low-fat diet-related concentrations of DCA had no effect. In vivo, the DCA-containing diet increased intestinal permeability 1.5-fold compared with control ( P = 0.016). Hematoxylin-eosin staining showed a clear disruption of the epithelial barrier by 3 mM DCA in vitro. A short-term treatment by DCA did not increase cyclooxygenase-2 content in colon preparations. UDCA did not affect barrier function itself, but it ameliorated DCA-induced barrier disruption at a 0.6 mM concentration. LPS had no significant effect on barrier function at 0.5–4.5 μg/ml concentrations. We suggest a novel mechanism for barrier dysfunction on a high-fat diet involving the effect of hydrophobic luminal bile acids.
Evidence of functional cross talk between the Notch and NF-κB pathways in nonneoplastic hyperproliferating colonic epithelium
Authors: Ahmed Ishfaq , Roy Badal , Chandrakesan Parthasarathy , Venugopal Anand , Xia Lijun , Jensen Roy , Anant Shrikant , Umar Shahid
Published: November 2012

The Notch and NF-κB signaling pathways regulate stem cell function and inflammation in the gut, respectively. We investigate whether a functional cross talk exists between the two pathways during transmissible murine colonic hyperplasia (TMCH) caused by Citrobacter rodentium (CR). During TMCH, NF-κB activity and subunit phosphorylation in colonic crypts of NIH Swiss mice at days 6 and 12 were associated with increases in downstream target CXC chemokine ligand (CXCL)-1/keratinocyte-derived chemokine (KC) expression. Blocking Notch signaling acutely for 5 days with the Notch blocker dibenzazepine (DBZ) failed to inhibit crypt NF-κB activity or CXCL-1/KC expression. Chronic DBZ administration for 10 days, however, blocked Notch and NF-κB signaling in the crypts and abrogated hyperplasia. Intriguingly, chronic Notch inhibition was associated with significant increases in IL-1α, granulocyte colony-stimulating factor, monocyte chemoattractant protein 1, macrophage inflammatory protein 2, and KC in the crypt-denuded lamina propria or whole distal colon, with concomitant increases in myeloperoxidase activity. In core-3−/−mice, which are defective in intestinal mucin, DBZ administration replicated the results of NIH Swiss mice; in ApcMin/+mice, which are associated with CR-induced elevation of NF-κB-p65276expression, DBZ reversed the increase in NF-κB-p65276, which may have blocked rapid proliferation of the mutated crypts. DBZ further blocked reporter activities involving the NF-κB-luciferase reporter plasmid or the Toll-like receptor 4/NF-κB/SEAPorter HEK-293 reporter cell line, while ectopic expression of Notch-NICDreversed the inhibitory effect. Dietary bael ( Aegle marmelos ) extract (4%) and curcumin (4%) restored Notch and NF-κB cross talk in NIH Swiss mice, inhibited CR/DBZ-induced apoptosis in the crypts, and promoted crypt regeneration. Thus functional cross talk between the Notch and NF-κB pathways during TMCH regulates hyperplasia and/or inflammation in response to CR infection.
Ginkgo biloba extract attenuates oxLDL-induced endothelial dysfunction via an AMPK-dependent mechanism
Authors: Ou Hsiu-Chung , Hsieh Yueh-Ling , Yang Nae-Cherng , Tsai Kun-Ling , Chen Kai-Ling , Tsai Chiou-Sheng , Chen I-Ju , Wu Bor-Tsang , Lee Shin-Da
Published: November 2012

Atherosclerosis is a complex inflammatory arterial disease, and oxidized low-density lipoprotein (oxLDL) is directly associated with chronic vascular inflammation. Previous studies have shown that Ginkgo biloba extract (GbE) acts as a therapeutic agent for neurological and cardiovascular disorders. However, the mechanisms mediating the actions of GbE are still largely unknown. In the present study, we tested the hypothesis that GbE protects against oxLDL-induced endothelial dysfunction via an AMP-activated protein kinase (AMPK)-dependent mechanism. Human umbilical vein endothelial cells were treated with GbE, followed by oxLDL, for indicated time periods. Results from Western blot showed that GbE inhibited the membrane translocation of the NADPH oxidase subunits p47phox and Rac-1 and attenuated the increase in protein expression of membrane subunits gp91 and p22phox caused by oxLDL-induced AMPK dephosphorylation and subsequent PKC activation. AMPK-α1-specific small interfering RNA-transfected cells that had been exposed to GbE followed by oxLDL revealed elevated levels of PKC and p47phox. In addition, exposure to oxLDL resulted in reduced AMPK-mediated Akt/endothelial nitric oxide (NO) synthase signaling and the induction of phosphorylation of p38 mitogen-activated protein kinase, which, in turn, activated NF-κB-mediated inflammatory responses, such as the release of interleukin-8, the expression of the adhesion molecule, and the adherence of monocytic cells to human umbilical vein endothelial cells. Furthermore, oxLDL upregulated the expression of inducible NO synthase, thereby augmenting the formation of NO and protein nitrosylation. Pretreatment with GbE, however, exerted significant cytoprotective effects in a dose-dependent manner. Results from this study may provide insight into a possible molecular mechanism by which GbE protects against oxLDL-induced endothelial dysfunction.
Decrease of airway smooth muscle contractility induced by simulated breathing maneuvers is not simply proportional to strain
Authors: Pascoe Chris D. , Seow Chun Y. , Paré Peter D. , Bossé Ynuk
Published: November 2012

The lung is a dynamic organ and the oscillating stress applied to the airway wall during breathing maneuvers can decrease airway smooth muscle (ASM) contractility. However, it is unclear whether it is the stress or the attendant strain that is responsible for the decline of ASM force associated with breathing maneuvers, and whether tone can prevent the decline of force by attenuating the strain. To investigate these questions, ovine tracheal strips were subjected to oscillating stress that simulates breathing maneuvers, and the resulting strain and decline of force were measured in the absence or presence of different levels of tone elicited by acetylcholine. In relaxed ASM, high stress simulating 20 cm H2O-transpulmonary pressure excursions strained ASM strips by 20.7% and decreased force by 17.1%. When stress oscillations were initiated during measurement of ACh concentration-response curves, tone almost abrogated strain at an ACh concentration of 10−6 M (1.1%) but the decline of force was not affected (18.9%). When stress oscillations were initiated after ACh-induced contraction had reached its maximal force, strain was almost abrogated at an ACh concentration of 10−6 M (0.9%) and the decline of force was attenuated (10.1%). However, even at the highest ACh concentration (10−4 M), substantial decline of force (6.1%) was still observed despite very small strain (0.7%). As expected, the results indicate that tone attenuated the strain experienced by ASM during breathing maneuver simulations. More surprisingly, the reduction of strain induced by tone was not proportional to its effect on the decline of force induced by simulated breathing maneuvers.
Progressive improvement in hemodynamic response to muscle metaboreflex in heart transplant recipients
Authors: Crisafulli Antonio , Tocco Filippo , Milia Raffaele , Angius Luca , Pinna Marco , Olla Sergio , Roberto Silvana , Marongiu Elisabetta , Porcu Maurizio , Concu Alberto
Published: November 2012

Exercise capacity remains lower in heart transplant recipients (HTRs) following transplant compared with normal subjects, despite improved cardiac function. Moreover, metaboreceptor activity in the muscle has been reported to increase. The aim of the present investigation was to assess exercise capacity together with metaboreflex activity in HTR patients for 1 yr following heart transplant, to test the hypothesis that recovery in exercise capacity was paralleled by improvements in response to metaboreflex. A cardiopulmonary test for exercise capacity and V̇o2maxand hemodynamic response to metaboreflex activation obtained by postexercise ischemia were gathered in six HTRs and nine healthy controls (CTL) four times: at the beginning of the study (T0, 42 ± 6 days after transplant), at the 3rd, 6th, and 12th month after TO (T1, T2, and T3). The main results were: 1) exercise capacity and V̇o2maxwere seen to progressively increase in HTRs; 2) at T0 and T1, HTRs achieved a higher blood pressure response in response to metaboreflex compared with CTL, and this difference disappeared at T2 and T3; and 3) this exaggerated blood pressure response was the result of a systemic vascular resistance increment. This study demonstrates that exercise capacity progressively improves in HTRs after transplant and that this phenomenon is accompanied by a progressive reduction of the metaboreflex-induced increase in blood pressure and systemic vascular resistance. These facts indicate that, despite improved cardiac function, resetting of cardiovascular regulation in HTRs requires months.
Atrial natriuretic peptide attenuates agonist-induced pulmonary edema in mice with targeted disruption of the gene for natriuretic peptide receptor-A
Authors: Klinger James R. , Tsai Shu-Whei , Green Sabrina , Grinnell Katie L. , Machan Jason T. , Harrington Elizabeth O.
Published: November 2012

Atrial natriuretic peptide (ANP) inhibits agonist-induced pulmonary edema formation, but the signaling pathway responsible is not well defined. To investigate the role of the particulate guanylate cyclase-linked receptor, natriuretic peptide receptor-A (NPR-A), we measured acute lung injury responses in intact mice and pulmonary microvascular endothelial cells (PMVEC) with normal and disrupted expression of NPR-A. NPR-A wild-type (NPR-A+/+), heterozygous (NPR-A+/−), and knockout (NPR-A−/−) mice were anesthetized and treated with thrombin receptor agonist peptide (TRAP) or lipopolysaccharide (LPS). Lung injury was assessed by lung wet-to-dry (W/D) weight and by protein and cell concentration of bronchoalveolar lavage (BAL) fluid. No difference in pulmonary edema formation was seen between NPR-A genotypes under baseline conditions. TRAP and LPS increased lung W/D weight and BAL fluid cell counts more in NPR-A−/− mice than in NPR-A+/− or NPR-A+/+ mice, but no genotype-related differences were seen in TRAP-induced increases in bloodless lung W/D weight or LPS-induced increases in BAL protein concentration. Pretreatment with ANP infusion completely blocked TRAP-induced increases in lung W/D weight and blunted LPS-induced increases in BAL cell counts and protein concentration in both NPR-A−/− and NPR-A+/+ mice. Thrombin decreased transmembrane electrical resistance in monolayers of PMVECs in vitro, and this effect was attenuated by ANP in PMVECs isolated from both genotypes. Administration of the NPR-C-specific ligand, cANF, also blocked TRAP-induced increases in lung W/D weight and LPS-induced increases in BAL cell count and protein concentration in NPR-A+/+ and NPR-A−/− mice. We conclude that ANP is capable of attenuating agonist-induced lung edema in the absence of NPR-A. The protective effect of ANP on agonist-induced lung injury and pulmonary barrier function may be mediated by NPR-C.
Corticospinal excitability is enhanced after visuomotor adaptation and depends on learning rather than performance or error
Authors: Bagce Hamid F. , Saleh Soha , Adamovich Sergei V. , Krakauer John W. , Tunik Eugene
Published: November 2012

We used adaptation to high and low gains in a virtual reality setup of the hand to test competing hypotheses about the excitability changes that accompany motor learning. Excitability was assayed through changes in amplitude of motor evoked potentials (MEPs) in relevant hand muscles elicited with single-pulse transcranial magnetic stimulation (TMS). One hypothesis is that MEPs will either increase or decrease, directly reflecting the effect of low or high gain on motor output. The alternative hypothesis is that MEP changes are not sign dependent but rather serve as a marker of visuomotor learning, independent of performance or visual-to-motor mismatch (i.e., error). Subjects were required to make flexion movements of a virtual forefinger to visual targets. A gain of 1 meant that the excursions of their real finger and virtual finger matched. A gain of 0.25 (“low gain”) indicated a 75% reduction in visual versus real finger displacement, a gain of 1.75 (“high gain”) the opposite. MEP increases (>40%) were noted in the tonically activated task-relevant agonist muscle for both high- and low-gain perturbations after adaptation reached asymptote with kinematics matched to veridical levels. Conversely, only small changes in excitability occurred in a control task of pseudorandom gains that required adjustments to large errors but in which learning could not accumulate. We conclude that changes in corticospinal excitability are related to learning rather than performance or error.
Deep brain stimulation entrains local neuronal firing in human globus pallidus internus
Authors: Cleary Daniel R. , Raslan Ahmed M. , Rubin Jonathan E. , Bahgat Diaa , Viswanathan Ashwin , Heinricher Mary M. , Burchiel Kim J.
Published: November 2012

Deep brain stimulation (DBS) in the internal segment of the globus pallidus (GPi) relieves the motor symptoms of Parkinson's disease, yet the mechanism of action remains uncertain. To address the question of how therapeutic stimulation changes neuronal firing in the human brain, we studied the effects of GPi stimulation on local neurons in unanesthetized patients. Eleven patients with idiopathic Parkinson's disease consented to participate in neuronal recordings during stimulator implantation surgery. A recording microelectrode and a DBS macroelectrode were advanced through the GPi in parallel until a single neuron was isolated. After a baseline period, stimulation was initiated with varying voltages and different stimulation sites. The intra-operative stimulation parameters (1–8 V, 88–180 Hz, 0.1-ms pulses) were comparable with the postoperative DBS settings. Stimulation in the GPi did not silence local neuronal activity uniformly, but instead loosely entrained firing and decreased net activity in a voltage-dependent fashion. Most neurons had decreased activity during stimulation, although some increased or did not change firing rate. Thirty-three of 45 neurons displayed complex patterns of entrainment during stimulation, and burst-firing was decreased consistently after stimulation. Recorded spike trains from patients were used as input into a model of a thalamocortical relay neuron. Only spike trains that occurred during therapeutically relevant voltages significantly reduced transmission error, an effect attributable to changes in firing patterns. These data indicate that DBS in the human GPi does not silence neuronal activity, but instead disrupts the pathological firing patterns through loose entrainment of neuronal activity.
Laminar dependence of neuronal correlations in visual cortex
Authors: Smith Matthew A. , Jia Xiaoxuan , Zandvakili Amin , Kohn Adam
Published: November 2012

Neuronal responses are correlated on a range of timescales. Correlations can affect population coding and may play an important role in cortical function. Correlations are known to depend on stimulus drive, behavioral context, and experience, but the mechanisms that determine their properties are poorly understood. Here we make use of the laminar organization of cortex, with its variations in sources of input, local circuit architecture, and neuronal properties, to test whether networks engaged in similar functions but with distinct properties generate different patterns of correlation. We find that slow timescale correlations are prominent in the superficial and deep layers of primary visual cortex (V1) of macaque monkeys, but near zero in the middle layers. Brief timescale correlation (synchrony), on the other hand, was slightly stronger in the middle layers of V1, although evident at most cortical depths. Laminar variations were also apparent in the power of the local field potential, with a complementary pattern for low frequency (<10 Hz) and gamma (30–50 Hz) power. Recordings in area V2 revealed a laminar dependence similar to V1 for synchrony, but slow timescale correlations were not different between the input layers and nearby locations. Our results reveal that cortical circuits in different laminae can generate remarkably different patterns of correlations, despite being tightly interconnected.
Hypomethylating Therapy in an Aggressive Stroma-Rich Model of Pancreatic Carcinoma
Authors: Shakya Reena , Gonda Tamas , Quante Michael , Salas Martha , Kim Samuel , Brooks Jenna , Hirsch Steffen , Davies Justine , Cullo Angelica , Olive Kenneth , Wang Timothy C. , Szabolcs Matthias , Tycko Benjamin , Ludwig Thomas
Published: November 2012

Pancreatic ductal adenocarcinoma (PDAC) is a lethal malignancy that resists current treatments. To test epigenetic therapy against this cancer, we used the DNA demethylating drug 5-aza-2′-deoxycytidine (DAC) in an aggressive mouse model of stromal rich PDAC (KPC-Brca1 mice). In untreated tumors, we found globally decreased 5-methyl-cytosine (5-mC) in malignant epithelial cells and in cancer-associated myofibroblasts (CAF), along with increased amounts of 5-hydroxymethyl-cytosine (5-HmC) in CAFs, in progression from pancreatic intraepithelial neoplasia to PDAC. DAC further reduced DNA methylation and slowed PDAC progression, markedly extending survival in an early-treatment protocol and significantly though transiently inhibiting tumor growth when initiated later, without adverse side effects. Escaping tumors contained areas of sarcomatoid transformation with disappearance of CAFs. Mixing-allografting experiments and proliferation indices showed that DAC efficacy was due to inhibition of both the malignant epithelial cells and the CAFs. Expression profiling and immunohistochemistry highlighted DAC induction of STAT1 in the tumors, and DAC plus IFN-γ produced an additive antiproliferative effect on PDAC cells. DAC induced strong expression of the testis antigen deleted in azoospermia-like (DAZL) in CAFs. These data show that DAC is effective against PDAC in vivo and provide a rationale for future studies combining hypomethylating agents with cytokines and immunotherapy. Cancer Res; 73(2); 885–96. ©2012 AACR.
Trastuzumab-Resistant Cells Rely on a HER2-PI3K-FoxO-Survivin Axis and Are Sensitive to PI3K Inhibitors
Authors: Chakrabarty Anindita , Bhola Neil E. , Sutton Cammie , Ghosh Ritwik , Kuba María Gabriela , Dave Bhuvanesh , Chang Jenny C. , Arteaga Carlos L.
Published: November 2012

The antibody trastuzumab is approved for treatment of patients with HER2 (ERBB2)-overexpressing breast cancer. A significant fraction of these tumors are either intrinsically resistant or acquire resistance rendering the drug ineffective. The development of resistance has been attributed to failure of the antibody to inhibit phosphoinositide 3-kinase (PI3K), which is activated by the HER2 network. Herein, we examined the effects of PI3K blockade in trastuzumab-resistant breast cancer cell lines. Treatment with the pan-PI3K inhibitor XL147 and trastuzumab reduced proliferation and pAKT levels, triggering apoptosis of trastuzumab-resistant cells. Compared with XL147 alone, the combination exhibited a superior antitumor effect against trastuzumab-resistant tumor xenografts. Furthermore, treatment with XL147 and trastuzumab reduced the cancer stem-cell (CSC) fraction within trastuzumab-resistant cells both in vitro and in vivo. These effects were associated with FoxO-mediated inhibition of transcription of the antiapoptosis gene survivin (BIRC5) and the CSC-associated cytokine interleukin-8. RNA interference–mediated or pharmacologic inhibition of survivin restored sensitivity to trastuzumab in resistant cells. In a cohort of patients with HER2-overexpressing breast cancer treated with trastuzumab, higher pretreatment tumor levels of survivin RNA correlated with poor response to therapy. Together, our results suggest that survivin blockade is required for therapeutic responses to trastuzumab and that by combining trastuzumab and PI3K inhibitors, CSCs can be reduced within HER2+ tumors, potentially preventing acquired resistance to anti-HER2 therapy. Cancer Res; 73(3); 1190–200. ©2012 AACR.
miR-186 Downregulation Correlates with Poor Survival in Lung Adenocarcinoma, Where It Interferes with Cell-Cycle Regulation
Authors: Cai Junchao , Wu Jueheng , Zhang Huizhong , Fang Lishan , Huang Yongbo , Yang Yi , Zhu Xun , Li Rong , Li Mengfeng
Published: November 2012

Deeper mechanistic understanding of lung adenocarcinoma (non–small cell lung carcinoma, or NSCLC), a leading cause of cancer-related deaths overall, may lead to more effective therapeutic strategies. In analyzing NSCLC clinical specimens and cell lines, we discovered a uniform decrease in miR-186 (MIR186) expression in comparison with normal lung tissue or epithelial cell lines. miR-186 expression correlated with patient survival, with median overall survival time of 63.0 or 21.5 months in cases exhibiting high or low levels of miR-186, respectively. Enforced overexpression of miR-186 in NSCLC cells inhibited proliferation by inducing G1–S checkpoint arrest. Conversely, RNA interference–mediated silencing miR-186 expression promoted cell-cycle progression and accelerated the proliferation of NSCLC cells. Cyclin D1 (CCND1), cyclin-dependent kinase (CDK)2, and CDK6 were each directly targeted for inhibition by miR-186 and restoring their expression reversed miR-186–mediated inhibition of cell-cycle progression. The inverse relationship between expression of miR-186 and its targets was confirmed in NSCLC tumor xenografts and clinical specimens. Taken together, our findings established a tumor-suppressive role for miR-186 in the progression of NSCLC. Cancer Res; 73(2); 756–66. ©2012 AACR.
Expression of CD137 on Hodgkin and Reed–Sternberg Cells Inhibits T-cell Activation by Eliminating CD137 Ligand Expression
Authors: Ho Weng Tong , Pang Wan Lu , Chong Siew Meng , Castella Antonio , Al-Salam Suhail , Tan Teng Ee , Moh Mei Chung , Koh Liang Kai , Gan Shu Uin , Cheng Cheong Kin , Schwarz Herbert
Published: November 2012

Hodgkin lymphoma is caused by a minority population of malignant Hodgkin and Reed–Sternberg (HRS) cells that recruit an abundance of inflammatory cells. The long-term survival of HRS cells among the vast majority of immune cells indicates that they have developed potent immune escape mechanisms. We report that the TNF receptor family member CD137 (TNFRSF9) is expressed on HRS cells, while normal B cells, from which HRS cells are most often derived, do not express CD137. In 48 of 53 cases of classical Hodgkin lymphoma, CD137 was detected on HRS cells. Ectopically expressed CD137 transferred by trogocytosis from HRS cells to neighboring HRS and antigen-presenting cells, which constitutively express the CD137 ligand (CD137L and TNFSF9), became associated with CD137L and the CD137–CD137L complex was internalized. Disappearance of CD137L from the surface of HRS and antigen-presenting cells led to reduced costimulation of T cells through CD137, reducing IFN-γ release and proliferation. Our results reveal a new regulatory mechanism for CD137L expression that mediates immune escape by HRS cells, and they identify CD137 as a candidate target for immunotherapy of Hodgkin lymphoma. Cancer Res; 73(2); 652–61. ©2012 AACR.