bluuebunny/crossref_metadata_2025 huggingface dataset:
Cultural Appropriation and the Crafting of Racialized Selves in American Youth Organizations
Authors: Strong Pauline Turner
Published: December 2008

This article considers three moments in the history of Camp Fire, the first American multiracial organization for girls: (1) the foundation of the organization in the 1910s through the 1930s by progressive reformers heavily influenced by ethnological scholarship on Native American rituals and symbolism; (2) the transformation of the organization into a coeducational organization in the 1970s; and (3) current efforts in the organization, now known as Camp Fire USA, to bring its activities more in line with contemporary multiculturalism while retaining its “Indian” traditions as the organization's heritage. These three historical moments are explored through a combination of archival research, interviews, and participant-observation. As a case study, the history of Camp Fire offers the opportunity to (1) deepen our knowledge of the American tradition of “playing Indian” and (2) track changes and continuities in the relationship among race, culture, gender, and sexuality in U.S. informal education.
Organizational Production of Self-Censorship in the Hong Kong Media
Authors: Lee Francis L.F. , Chan Joseph
Published: December 2008

Media self-censorship refers to nonexternally compelled acts committed by media organizations aiming to avoid offending power holders such as the government, advertisers, and major business corporations. While self-censorship constitutes a major threat to press freedom in Hong Kong under China, recent studies have shown that Hong Kong journalists have maintained a strong sense of professionalism. The coexistence of professionalism and self-censorship poses important challenges to news organizations: How is self-censorship effected as professionalism does not favor its practice? How can news organizations minimize the conflicts between self-censorship and professionalism so that news operations will remain stable, smooth, and efficient? Drawing on the literature on newsroom social control, we tackle the above questions by focusing on the internal structure of and the interactive dynamics within newsrooms. Methodologically, this study draws on both representative survey and in-depth interview data. It is found that self-censorship is effected through selective positioning and assignment, observational learning of tacit rules, the giving of ambiguous orders, and the use of professional or technical reasons to justify questionable news decisions. Meanwhile, some journalists also developed their own operational tactics to resist what they perceived as self-censorship attempts. The theoretical implications of the findings are discussed.
Reversed Mobilization in Referendum Campaigns
Authors: Schuck Andreas R.T. , de Vreese Claes H.
Published: December 2008

This multimethodological study focuses on risk-induced electoral mobilization in referendum campaigns. Positive news framing in a referendum campaign can generate a perception of risk among those voters opposing the proposal and stimulate electoral participation to prevent an undesired outcome that would alter a status quo situation. To test this claim, the authors analyze the effect of news framing on turnout in the context of the 2005 Dutch EU Constitution referendum campaign and combine a media content analysis of national newspapers and television news ( n = 6,370) with panel survey data ( n = 642) and an experiment ( n = 687). Experimental findings show that individuals who are skeptical toward the EU and are subsequently exposed to positive news framing about the EU Constitution are mobilized to turn out and vote against it. The results of the content analysis show that during the Dutch referendum campaign, news media framed the EU Constitution in positive terms. Building these findings into a measure of news exposure in our panel survey, the authors find that higher exposure to referendum news had a mobilizing effect on those opposing the proposal. The experimental and panel data thus show corroborating evidence supporting the central hypothesis about how positive news can mobilize the skeptics to turn out and vote in a referendum.
Creativity and the Experts
Authors: Schlesinger Philip
Published: December 2008

This article explores the role of expertise in public debate on creative industries policy in the United Kingdom. The first section gives an overview of the emergence of expertise in government and the rise of think tanks, locating this within a wider sociology of the intellectuals. It discusses the development of New Labour expertise in response to that of Thatcherite Conservatism in the battle to dominate public policy agendas. The second section illustrates the growth of the New Labour “policy generation” and the emergence of a cohort of experts in the fields of media, communications, and culture and discusses routes taken by them into government. The final section, based on interviews, discusses the power plays behind New Labour policy making in the creative industries field. It considers the impact of ministerial changes on the policy process, illustrates how interdepartmental rivalries introduce complexity and demonstrates how civil service expertise may be mobilised to neutralise that of outside experts. The conclusion addresses the implications of this analysis.
Effect of temperature on mechanical characteristics of copper–chromium composite
Authors: Bukhanovsky V. V. , Rudnitsky N. P. , Mamuzich I.
Published: December 2008

The structure, hardness, strength and plasticity of a microlayer Cu–Cr composite for interrupter contacts in vacuum circuit breakers, which is obtained by electron beam physical vapour deposition, were studied over a temperature range of 290–1070 K. Correlation between the hardness and strength of the composite was established.
Processing strategy for laser forming of complicated singly curved shapes
Authors: Shi Y. J. , Chen J. , Qi Y. G. , Yao Z. Q.
Published: December 2008

Laser forming is a flexible sheet metal forming technique, which achieves a desirable shape by non-uniform thermal stress induced by laser beam without hard tooling and external forces. In engineering applications, a singly curved surface is extensively applied in forming parts. To acquire high accurate shape in laser forming, a new design approach is proposed to determinate path planning and process parameters of complicated singly curved shape. This approach mainly includes three steps, curve division, path planning and process parameters determination. Finally, to validate the effectiveness of the method, a sine curved plate is processed. The experimental result shows that the proposed approach is valid for complicated singly curved parts.
New numerical method for the fit of Garofalo equation and its application for predicting hot workability of a (V–N) microalloyed steel
Authors: Rieiro I. , Carsí M. , Ruano O. A.
Published: December 2008

A new method, Rieiro, Carsí, Ruano (RCR), for solving the Garofalo equation is developed. This method is based on an integrated algorithm that allows determination of the equation parameters for any given material and does not need initial values. The RCR method is used to analyse the Garofalo equation best fit applied to torsion data at various temperatures and strain rates from a (V–N) microalloyed steel. The predictive capability of the RCR method on experimental results is ∼6% in stress and the magnitude of the predicted errors is of the same order as the interpolation errors. On the other hand, the n value is slightly lower and the Q value slightly higher than those expected for a slip creep mechanism controlled by lattice diffusion. However, the obtained values agree with those found in the literature for microalloyed steels. These differences can be attributed to microstructure changes during deformation.
Investigation into constitutive behaviour for thin sheet based micro forming
Authors: Wang Y. , Dong P. L. , Xu Z. Y. , Yan H. , Yuan G. D.
Published: December 2008

The present paper investigated the influence of t/d (thickness/average grain size) on yield stress and tangent modulus in the micro tensile test of CuZn36 sheets. By using the double–linear elastic–plastic constitutive equation, the constitutive relation of size effects was established. The relation was based on the Mises yield criterion, the kinematic hardening model, and the experimental results from the micro tensile test. The incremental method flow chart was also obtained, which was used as a guideline in finite element analysis.
Study of welding peak temperatures on microstructures and hardness of heat affected zone in 2024-T3 aluminium alloy
Authors: Chen C. S. , Yang J. G. , Tan A. H.
Published: December 2008

The influence of welding thermal cycle peak temperatures and post-weld heat treatments on the microstructures and mechanical properties of the heat affected zone (HAZ) for 2024-T3 aluminium alloy have been investigated by Gleeble HAZ simulation. Differential scanning calorimetry (DSC) in conjunction with transmission electron microscopy (TEM) is used to characterise the HAZ microstructures. The welded HAZ in the region of peak temperature 414°C has the lowest hardness after natural aged temper, which is primarily due to the precipitation and coarsening of stable S phases. When the peak temperature of welded HAZ is larger than 414°C, the hardness of HAZ increasing with an increasing peak temperature can be seen, which is due to higher peak temperature thermal cycles treatment inducing the dissolution of precipitations in the matrix, and, after the natural aging treatment, Guinier-Preston (GPB) and GPB2 zones precipitating out in the matrix again can be seen. Post-weld T81 artificial aging (PWAA-T81) heat treatment has no effect on improving the HAZ hardness; the HAZ hardness of the 2024-T3 alloy obtained by PWAA-T81 is less than that obtained by natural aging, and its lowest hardness is shifted to the region of peak temperature, which is 452°C, because overaging induces coarse and sparse amounts of stable S phase.
The endothelial antigen ESAM marks primitive hematopoietic progenitors throughout life in mice
Authors: Yokota Takafumi , Oritani Kenji , Butz Stefan , Kokame Koichi , Kincade Paul W. , Miyata Toshiyuki , Vestweber Dietmar , Kanakura Yuzuru
Published: December 2008

Although recent advances have enabled hematopoietic stem cells (HSCs) to be enriched to near purity, more information about their characteristics will improve our understanding of their development and stage-related functions. Here, using microarray technology, we identified endothelial cell-selective adhesion molecule (ESAM) as a novel marker for murine HSCs in fetal liver. Esam was expressed at high levels within a Rag1− c-kitHi Sca1+ HSC-enriched fraction, but sharply down-regulated with activation of the Rag1 locus, a valid marker for the most primitive lymphoid progenitors in E14.5 liver. The HSC-enriched fraction could be subdivided into 2 on the basis of ESAM levels. Among endothelial antigens on hematopoietic progenitors, ESAM expression showed intimate correlation with HSC activity. The ESAMHi population was highly enriched for multipotent myeloid-erythroid progenitors and primitive progenitors with lymphopoietic activity, and exclusively reconstituted long-term lymphohematopoiesis in lethally irradiated recipients. Tie2+ c-kit+ lymphohematopoietic cells in the E9.5–10.5 aorta-gonad-mesonephros region also expressed high levels of ESAM. Furthermore, ESAM was detected on primitive hematopoietic progenitors in adult bone marrow. Interestingly, ESAM expression in the HSC-enriched fraction was up-regulated in aged mice. We conclude that ESAM marks HSC in murine fetal liver and will facilitate studies of hematopoiesis throughout life.
ATM-ATR–dependent up-regulation of DNAM-1 and NKG2D ligands on multiple myeloma cells by therapeutic agents results in enhanced NK-cell susceptibility and is associated with a senescent phenotype
Authors: Soriani Alessandra , Zingoni Alessandra , Cerboni Cristina , Iannitto Maria Luisa , Ricciardi Maria Rosaria , Di Gialleonardo Valentina , Cippitelli Marco , Fionda Cinzia , Petrucci Maria Teresa , Guarini Anna , Foà Robin , Santoni Angela
Published: December 2008

There is much evidence to support a role for natural killer (NK) cells in controlling the progression of multiple myeloma (MM), a malignancy characterized by an abnormal plasma cell proliferation in the bone marrow (BM). Induction of DNA damage response has been recently shown capable of enhancing NKG2D ligand (NKG2DL) expression, but nothing is known about DNAM-1 ligand (DNAM-1L) regulation. In this study, we show that myeloma cells treated with low doses of therapeutic agents commonly used in the management of patients with MM, such as doxorubicin, melphalan, and bortezomib, up-regulate DNAM-1 and NKG2D ligands. Accordingly, therapeutic drug treatment of MM cells increases NK-cell degranulation, the NKG2D and DNAM-1 receptors being the major triggering molecules. Similar data were also obtained using ex vivo primary plasma cells derived from MM patients. Drug-induced DNAM-1 and NKG2D ligand expression was abolished after treatment with the ATM (ataxia telangiectasia mutated) and ATR (ATM- and RAD3-related) pharmacologic inhibitors caffeine and KU-55933, and was preferentially associated with senescent cells arrested in the G2 phase of the cell cycle. Altogether, our findings have identified a common pathway that can trigger the up-regulation of different NK cell–activating ligands and suggest that NK cells represent an immunosurveillance mechanism toward cells undergoing stress-induced senescent programs.
Primary central nervous system lymphoma: tumor-related clones exist in the blood and bone marrow with evidence for separate development
Authors: McCann Katy J. , Ashton-Key Margaret , Smith KellyAnn , Stevenson Freda K. , Ottensmeier Christian H.
Published: December 2008

Primary central nervous system (CNS) lymphoma is an aggressive B-cell tumor that is defined clinically by the absence of systemic disease. We have used immunoglobulin variable (V)–gene analysis to identify tumor cells at the CNS site in 12 cases and to probe the involvement of peripheral tissues in 3 patients. Clonal tracking revealed tumor cells in the bone marrow and/or blood for 3 of 3 cases, with evidence for increased V-gene mutational activity at peripheral sites. In 2 of 3 cases, intraclonal variant analysis revealed identity with the brain biopsy but detected additional variants unique to extracerebral sites. These findings suggest that peripheral tumor cells can undergo separate development locally with no reentry into the brain. Primary CNS lymphoma appears to have both CNS-specific and systemic components with limited interchange. The more malignant behavior of tumor cells in the CNS suggests either a local environmental influence or a less malignant phenotype of the peripheral clone.
GeneChaser: Identifying all biological and clinical conditions in which genes of interest are differentially expressed
Authors: Chen Rong , Mallelwar Rohan , Thosar Ajit , Venkatasubrahmanyam Shivkumar , Butte Atul J
Published: December 2008

Background

The amount of gene expression data in the public repositories, such as NCBI Gene Expression Omnibus (GEO) has grown exponentially, and provides a gold mine for bioinformaticians, but has not been easily accessible by biologists and clinicians.

Results

We developed an automated approach to annotate and analyze all GEO data sets, including 1,515 GEO data sets from 231 microarray types across 42 species, and performed 12,658 group versus group comparisons of 24 GEO-specified types. We then built GeneChaser, a web server that enables biologists and clinicians without bioinformatics skills to easily identify biological and clinical conditions in which a gene or set of genes was differentially expressed. GeneChaser displays these conditions in graphs, gives statistical comparisons, allows sort/filter functions and provides access to the original studies.

We performed a single gene search for Nanog and a multiple gene search for Nanog, Oct4, Sox2 and LIN28, confirmed their roles in embryonic stem cell development, identified several drugs that regulate their expression, and suggested their potential roles in sex determination, abnormal sperm morphology, malaria infection, and cancer.

Conclusion

We demonstrated that GeneChaser is a powerful tool to elucidate information on function, transcriptional regulation, drug-response and clinical implications for genes of interest.
nGASP – the nematode genome annotation assessment project
Authors: Coghlan Avril , Fiedler Tristan J , McKay Sheldon J , Flicek Paul , Harris Todd W , Blasiar Darin ,   the nGASP Consortium, Stein Lincoln D
Published: December 2008

Background

While the C. elegans genome is extensively annotated, relatively little information is available for other Caenorhabditis species. The nematode genome annotation assessment project (nGASP) was launched to objectively assess the accuracy of protein-coding gene prediction software in C. elegans, and to apply this knowledge to the annotation of the genomes of four additional Caenorhabditis species and other nematodes. Seventeen groups worldwide participated in nGASP, and submitted 47 prediction sets across 10 Mb of the C. elegans genome. Predictions were compared to reference gene sets consisting of confirmed or manually curated gene models from WormBase.

Results

The most accurate gene-finders were 'combiner' algorithms, which made use of transcript- and protein-alignments and multi-genome alignments, as well as gene predictions from other gene-finders. Gene-finders that used alignments of ESTs, mRNAs and proteins came in second. There was a tie for third place between gene-finders that used multi-genome alignments and ab initio gene-finders. The median gene level sensitivity of combiners was 78% and their specificity was 42%, which is nearly the same accuracy reported for combiners in the human genome. C. elegans genes with exons of unusual hexamer content, as well as those with unusually many exons, short exons, long introns, a weak translation start signal, weak splice sites, or poorly conserved orthologs posed the greatest difficulty for gene-finders.

Conclusion

This experiment establishes a baseline of gene prediction accuracy in Caenorhabditis genomes, and has guided the choice of gene-finders for the annotation of newly sequenced genomes of Caenorhabditis and other nematode species. We have created new gene sets for C. briggsae, C. remanei, C. brenneri, C. japonica, and Brugia malayi using some of the best-performing gene-finders.
Genome wide association for substance dependence: convergent results from epidemiologic and research volunteer samples
Authors: Johnson Catherine , Drgon Tomas , Liu Qing-Rong , Zhang Ping-Wu , Walther Donna , Li Chuan-Yun , Anthony James C , Ding Yulan , Eaton William W , Uhl George R
Published: December 2008

Background

Dependences on addictive substances are substantially-heritable complex disorders whose molecular genetic bases have been partially elucidated by studies that have largely focused on research volunteers, including those recruited in Baltimore. Maryland. Subjects recruited from the Baltimore site of the Epidemiological Catchment Area (ECA) study provide a potentially-useful comparison group for possible confounding features that might arise from selecting research volunteer samples of substance dependent and control individuals. We now report novel SNP (single nucleotide polymorphism) genome wide association (GWA) results for vulnerability to substance dependence in ECA participants, who were initially ascertained as members of a probability sample from Baltimore, and compare the results to those from ethnically-matched Baltimore research volunteers.

Results

We identify substantial overlap between the home address zip codes reported by members of these two samples. We find overlapping clusters of SNPs whose allele frequencies differ with nominal significance between substance dependent vs control individuals in both samples. These overlapping clusters of nominally-positive SNPs identify 172 genes in ways that are never found by chance in Monte Carlo simulation studies. Comparison with data from human expressed sequence tags suggests that these genes are expressed in brain, especially in hippocampus and amygdala, to extents that are greater than chance.

Conclusion

The convergent results from these probability sample and research volunteer sample datasets support prior genome wide association results. They fail to support the idea that large portions of the molecular genetic results for vulnerability to substance dependence derive from factors that are limited to research volunteers.
Class I histone deacetylases 1, 2 and 3 are highly expressed in renal cell cancer
Authors: Fritzsche Florian R , Weichert Wilko , Röske Annika , Gekeler Volker , Beckers Thomas , Stephan Carsten , Jung Klaus , Scholman Katharina , Denkert Carsten , Dietel Manfred , Kristiansen Glen
Published: December 2008

Background

Enhanced activity of histone deacetylases (HDAC) is associated with more aggressive tumour behaviour and tumour progression in various solid tumours. The over-expression of these proteins and their known functions in malignant neoplasms has led to the development of HDAC inhibitors (HDI) as new anti-neoplastic drugs. However, little is known about HDAC expression in renal cell cancer.

Methods

We investigated the expression of HDAC 1, 2 and 3 in 106 renal cell carcinomas and corresponding normal renal tissue by immunohistochemistry on tissue micro arrays and correlated expression data with clinico-pathological parameters including patient survival.

Results

Almost 60% of renal cell carcinomas expressed the HDAC isoforms 1 and 2. In contrast, HDAC 3 was only detected in 13% of all renal tumours, with particular low expression rates in the clear cell subtype. HDAC 3 was significantly higher expressed in pT1/2 tumours in comparison to pT3/4 tumours. Expression of class I HDAC isoforms correlated with each other and with the proliferative activity of the tumours. We found no prognostic value of the expression of any of the HDAC isoforms in this tumour entity.

Conclusion

Class I HDAC isoforms 1 and 2 are highly expressed in renal cell cancer, while HDAC 3 shows low, histology dependent expression rates. These unexpected differences in the expression patterns suggests alternative regulatory mechanisms of class I HDACs in renal cell cancer and should be taken into account when trials with isoform selective HDI are being planned. Whether HDAC expression in renal cancers is predictive of responsiveness for HDI will have to be tested in further studies.
Provincial prenatal record revision: a multiple case study of evidence-based decision-making at the population-policy level
Authors: Edwards Nancy , Semenic Sonia , Premji Shahirose , Montgomery Phyllis , Williams Beverly , Olson Joanne , Mansi Omaima
Published: December 2008

Background

There is a significant gap in the knowledge translation literature related to how research evidence actually contributes to health care decision-making. Decisions around what care to provide at the population (rather than individual) level are particularly complex, involving considerations such as feasibility, cost, and population needs in addition to scientific evidence. One example of decision-making at this "population-policy" level involves what screening questions and intervention guides to include on standardized provincial prenatal records. As mandatory medical reporting forms, prenatal records are potentially powerful vehicles for promoting population-wide evidence-based care. However, the extent to which Canadian prenatal records reflect best-practice recommendations for the assessment of well-known risk factors such as maternal smoking and alcohol consumption varies markedly across Canadian provinces and territories. The goal of this study is to better understand the interaction of contextual factors and research evidence on decision-making at the population-policy level, by examining the processes by which provincial prenatal records are reviewed and revised.

Methods

Guided by Dobrow et al.'s (2004) conceptual model for context-based evidence-based decision-making, this study will use a multiple case study design with embedded units of analysis to examine contextual factors influencing the prenatal record revision process in different Canadian provinces and territories. Data will be collected using multiple methods to construct detailed case descriptions for each province/territory. Using qualitative data analysis techniques, decision-making processes involving prenatal record content specifically related to maternal smoking and alcohol use will be compared both within and across each case, to identify key contextual factors influencing the uptake and application of research evidence by prenatal record review committees. All study participants will be required to give written informed consent prior to participating in data collection.

Conclusion

This study will advance knowledge in the field of evidence-based decision-making by illustrating the complex interaction of contextual factors and evidence on health policy decision-making by provincial-level committees. By increasing the transparency of decision-making within provincial prenatal record committees, this study will help inform more effective strategies for enhancing the integration of best-practice evidence into prenatal records.
Monocytes are essential for inhibition of synovial T-cell glucocorticoid-mediated apoptosis in rheumatoid arthritis
Authors: Makrygiannakis Dimitrios , Revu Shankar , Neregård Petra , af Klint Erik , Snir Omri , Grundtman Cecilia , Catrina Anca Irinel
Published: December 2008

Introduction

Rheumatoid arthritis (RA) is characterized by synovial inflammation with local accumulation of mononuclear cells such as macrophages and lymphocytes. We previously demonstrated that intra-articular glucocorticoids decrease the synovial tissue (ST) T-cell population and therefore aimed to investigate whether this is mediated through modulation of apoptosis.

Methods

Apoptosis and cell phenotype were evaluated by immunohistochemistry and dual-immunofluorescence in synovial biopsy sections from 12 RA patients before and after a mean of 11 days of an intra-articular triamcinolone knee injection. In vitro, RA synovial fluid (SF)-derived T cells were evaluated for Annexin V expression by multicolor flow cytometry after 24-hour exposure to dexamethasone, methylprednisolone, or triamcinolone. We also tested induction of apoptosis by dexamethasone on psoriatic arthritis SF-derived T cells using the same method.

Results

Intra-articular glucocorticoids reduced ST T cells but not macrophage number. ST apoptosis levels were unchanged following treatment, virtually absent from lymphoid aggregates, and minimal in CD3+ cells both before and after treatment. RA SF T cells were resistant to glucocorticoid-induced apoptosis when cultured in the presence of monocytes but were rendered sensitive to all three tested compounds upon SF isolation. Furthermore, transwell coculture of monocytes and T cells demonstrated that soluble factor(s) and not cellular contact are essential for T-cell resistance to glucocorticoid-mediated apoptosis. This feature is RA-specific as far as dexamethasone-induced apoptosis in nonisolated SF T cells obtained from psoriatic arthritis patients is concerned.

Conclusions

We demonstrate that monocytes rescue synovial T cells from glucocorticoid-induced apoptosis, a feature that is specific for RA. To overcome this, we propose the use of monocyte-targeted therapies rather than T-cell apoptosis-inducing therapies.
Singular value decomposition-based regression identifies activation of endogenous signaling pathways in vivo
Authors: Liu Zhandong , Wang Min , Alvarez James V , Bonney Megan E , Chen Chien-chung , D'Cruz Celina , Pan Tien-chi , Tadesse Mahlet G , Chodosh Lewis A
Published: December 2008

The ability to detect activation of signaling pathways based solely on gene expression data represents an important goal in biological research. We tested the sensitivity of singular value decomposition-based regression by focusing on functional interactions between the Ras and transforming growth factor beta signaling pathways. Our findings demonstrate that this approach is sufficiently sensitive to detect the secondary activation of endogenous signaling pathways as it occurs through crosstalk following ectopic activation of a primary pathway.
Male reproductive development: gene expression profiling of maize anther and pollen ontogeny
Authors: Ma Jiong , Skibbe David S , Fernandes John , Walbot Virginia
Published: December 2008

Background

During flowering, central anther cells switch from mitosis to meiosis, ultimately forming pollen containing haploid sperm. Four rings of surrounding somatic cells differentiate to support first meiosis and later pollen dispersal. Synchronous development of many anthers per tassel and within each anther facilitates dissection of carefully staged maize anthers for transcriptome profiling.

Results

Global gene expression profiles of 7 stages representing 29 days of anther development are analyzed using a 44 K oligonucleotide array querying approximately 80% of maize protein-coding genes. Mature haploid pollen containing just two cell types expresses 10,000 transcripts. Anthers contain 5 major cell types and express >24,000 transcript types: each anther stage expresses approximately 10,000 constitutive and approximately 10,000 or more transcripts restricted to one or a few stages. The lowest complexity is present during meiosis. Large suites of stage-specific and co-expressed genes are identified through Gene Ontology and clustering analyses as functional classes for pre-meiotic, meiotic, and post-meiotic anther development. MADS box and zinc finger transcription factors with constitutive and stage-limited expression are identified.

Conclusions

We propose that the extensive gene expression of anther cells and pollen represents the key test of maize genome fitness, permitting strong selection against deleterious alleles in diploid anthers and haploid pollen. Because flowering plants show a substantial bias for male-sterile compared to female-sterile mutations, we propose that this fitness test is general. Because both somatic and germinal cells are transcriptionally quiescent during meiosis, we hypothesize that successful completion of meiosis is required to trigger maturation of anther somatic cells.
Adenosine and IFN-α synergistically increase IFN-γ production of human NK cells
Authors: Jeffe Florian , Stegmann Kerstin A , Broelsch Felix , Manns Michael P , Cornberg Markus , Wedemeyer Heiner
Published: December 2008

Prevention of overwhelming immune reactions is essential for an organism to survive. Adenosine, a ribonucleoside produced by various cell types during inflammatory processes, has been shown to inhibit effector functions of different immune cells. Here, we show that the adenosine A3 receptor agonist iodobenzyl methylcarboxamidoadenosine potently inhibited proliferation, IFN-γ production, and cytotoxicity of activated human lymphoid cells. Stimulation of the A3 receptor also caused apoptosis of activated PBMC. However, when PBMC were stimulated with IFN-α, adenosine did not decrease, but synergistically increased, the IFN-γ production of NK cells. This effect was also mediated mainly via the A3 receptor. Thus, our data suggest that adenosine differentially contributes to the regulation of immune responses during inflammatory processes: It may increase effector functions of NK cells in combination with IFN-α but also prevents overwhelming immune responses by inhibiting proliferation and induction of apoptosis of activated lymphoid cells. Future studies need to define the role of the different adenosine receptors in more detail.
Human eosinophils constitutively express multiple Th1, Th2, and immunoregulatory cytokines that are secreted rapidly and differentially
Authors: Spencer Lisa A , Szela Craig T , Perez Sandra A C , Kirchhoffer Casey L , Neves Josiane S , Radke Amy L , Weller Peter F
Published: December 2008

Eosinophils are innate immune leukocytes implicated in the initiation and maintenance of type 2 immune responses, including asthma and allergy. The ability to store and rapidly secrete preformed cytokines distinguishes eosinophils from most lymphocytes, which must synthesize cytokine proteins prior to secretion and may be a factor in the apparent Th2 bias of eosinophils. Multiple studies confirm that human eosinophils from atopic or hypereosinophilic donors can secrete over 30 cytokines with a varying and often opposing immune-polarizing potential. However, it remains unclear whether all of these cytokines are constitutively preformed and available for rapid secretion from eosinophils in the circulation of healthy individuals or are restricted to eosinophils from atopic donors. Likewise, the relative concentrations of cytokines stored within eosinophils have not been studied. Here, we demonstrate that human blood eosinophils are not singularly outfitted with Th2-associated cytokines but rather, constitutively store a cache of cytokines with nominal Th1, Th2, and regulatory capacities, including IL-4, IL-13, IL-6, IL-10, IL-12, IFN-γ, and TNF-α. We demonstrate further rapid and differential release of each cytokine in response to specific stimuli. As agonists, strong Th1 and inflammatory cytokines elicited release of Th2-promoting IL-4 but not Th1-inducing IL-12. Moreover, a large quantity of IFN-γ was secreted in response to Th1, Th2, and inflammatory stimuli. Delineations of the multifarious nature of preformed eosinophil cytokines and the varied stimulus-dependent profiles of rapid cytokine secretion provide insights into the functions of human eosinophils in mediating inflammation and initiation of specific immunity.
Statins alter neutrophil migration by modulating cellular Rho activity—a potential mechanism for statins-mediated pleotropic effects?
Authors: Maher B M , Dhonnchu T Ni , Burke J P , Soo A , Wood A E , Watson R W G
Published: December 2008

The ability of neutrophils to sense and migrate toward damaged tissue is a vital component of the innate immune response. Paradoxically, this same migration serves as the hallmark of a number of inflammatory conditions, including ischemic reperfusion injury, atherosclerosis, arthritis, and Crohn’s disease. More recent evidence suggests that neutrophil infiltration into the cardiac allograft following transplantation is a contributing factor in allograft rejection. We have demonstrated previously a positive correlation between the degree of neutrophil migration and subsequent rejection grades in a cohort of cardiac transplant recipients. Intracellular signaling pathways that are intimately involved in neutrophil migration thus offer potential targets of manipulation in the treatment of such conditions. 3-Hydroxy-3-methylyglutaryl-coenzyme A reductase inhibitors or statins are emerging as potential anti-inflammatory agents and have a proven survival benefit in the transplant population. Yet, little is known about their ability to modulate neutrophil function and their subsequent mechanism of action. We demonstrate here that pravastatin, simvastatin, and atorvastatin significantly reduce neutrophil transendothelial migration toward the chemoattractant fMLP. This effect is independent of any change in neutrophil adhesion or adhesion molecule expression but is related to the ability of statins to reduce fMLP-induced Rho activity in neutrophils. This was confirmed by the ability of the Rho precursor geranylgeranyl pyrophosphate to rescue the statin-mediated reduction in neutrophil transendothelial migration. Understanding the mechanisms of action of statins in the neutrophil allows for their use in targeting excessive migration in inappropriate inflammatory conditions.
Inhibition of spontaneous neutrophil apoptosis by parabutoporin acts independently of NADPH oxidase inhibition but by lipid raft-dependent stimulation of Akt
Authors: Remijsen Quinten , Vanden Berghe Tom , Parthoens Eef , Asselbergh Bob , Vandenabeele Peter , Willems Jean
Published: December 2008

Neutrophil cell death plays a crucial role in neutrophil homeostasis and the resolution of inflammation. The superoxide-producing NADPH oxidase is involved in pathogen degradation and subsequent activation of cell death programs. Neutrophils from patients with chronic granulomatous disease, who have a deficient NADPH oxidase activity, have been demonstrated previously to have a prolonged lifespan, suggesting that a basal NADPH oxidase activity also regulates spontaneous neutrophil turnover. The NADPH oxidase inhibitor parabutoporin (PP) does delay spontaneous apoptosis, but this effect is completely independent of NADPH oxidase inhibition. Instead, the prosurvival effect of PP depends on activation of protein kinase B/Akt via lipid raft signaling. Disruption of lipid rafts abrogates the prosurvival effect without interfering with NADPH oxidase activity. Furthermore, we cannot detect a different rate of spontaneous apoptosis between normal and NADPH oxidase-deficient neutrophils, arguing against a role of NADPH oxidase in spontaneous neutrophil apoptosis.
Unique Roles of p160 Coactivators for Regulation of Breast Cancer Cell Proliferation and Estrogen Receptor-α Transcriptional Activity
Authors: Karmakar Sudipan , Foster Estrella A. , Smith Carolyn L.
Published: December 2008

Each of the three members of the p160 steroid receptor coactivator (SRC) family of coactivators (SRC-1, SRC-2 and SRC-3) stimulates estrogen receptor (ER)-α function in trans-activation assays. Consequently, we sought to elucidate their contributions to the ER-regulated processes of cell proliferation, apoptosis, and the expression of ERα target genes in MCF-7 breast cancer cells. The small interfering RNA depletion of SRC-2 or SRC-3 but not SRC-1 inhibited growth of MCF-7 cells, and this was reflected in decreased cell cycle progression and increased apoptosis in SRC-2- or SRC-3-depleted cells as well as a reduction in ERα transcriptional activity measured on a synthetic reporter gene. However, only SRC-3 depletion blocked estradiol stimulated cell proliferation. Depletion of SRC-1 did not affect these events, and together this reveals functional differences between each of the three SRC family coactivators. Regulation of the endogenous ERα target gene, c-myc was not affected by depletion of any of the p160 coactivators although depletion of each of them decreased pS2 mRNA expression in estradiol-treated MCF-7 cells. Moreover, progesterone receptor and cyclin D1 gene expression were decreased in SRC-3 small interfering RNA-treated cells. Expression of mRNA and protein levels for the antiapoptotic gene, Bcl-2 was dependent on SRC-3 expression, whereas Bcl-2 protein but not mRNA expression also was sensitive to SRC-1 depletion. Together these data indicate that the closely related p160 coactivators are not functionally redundant in breast cancer cells because they play gene-specific roles in regulating mRNA and protein expression, and they therefore are likely to make unique contributions to breast tumorigenesis.
Aldosterone Inhibits Insulin-Induced Glucose Uptake by Degradation of Insulin Receptor Substrate (IRS) 1 and IRS2 via a Reactive Oxygen Species-Mediated Pathway in 3T3-L1 Adipocytes
Authors: Wada Tsutomu , Ohshima Satoshi , Fujisawa Eriko , Koya Daisuke , Tsuneki Hiroshi , Sasaoka Toshiyasu
Published: December 2008

Serum aldosterone level is clinically known to correlate with body weight and insulin resistance. Because the underlying molecular mechanism is largely unknown, we examined the effect of aldosterone on insulin-induced metabolic signaling leading to glucose uptake in 3T3-L1 adipocytes. Aldosterone reduced the amounts of insulin receptor substrate (IRS) 1 and IRS2 in a time- and dose-dependent manner. As a result, insulin-induced phosphorylation of Akt-1 and -2, and subsequent uptake of 2-deoxyglucose were decreased. Degradation of IRSs was effectively prevented by a glucocorticoid receptor antagonist and antioxidant N-acetylcysteine, but not by a mineralocorticoid receptor antagonist. Because aldosterone induced phosphorylation of IRS1 at Ser307, responsible kinases were investigated, and we revealed that rapamycin and BMS345541, but neither SP600125 nor calphostin C, conferred for degradation of IRSs. Although lactacystin prevented the degradation of IRSs, glucose uptake was not preserved. Importantly, sucrose-gradient-sediment intracellular fraction analysis revealed that lactacystin did not effectively restore the reduction of IRS1 in the low-density microsome fraction, important for the transduction of insulin’s metabolic signaling. These results indicate that aldosterone deteriorates metabolic action of insulin by facilitating the degradation of IRS1 and IRS2 via glucocorticoid receptor-mediated production of reactive oxygen species, and activation of IκB Kinase β and target of rapamycin complex 1. Thus, aldosterone appears to be a novel key factor in the development of insulin resistance in visceral obesity.
Maturation of Adult β-Cells Revealed Using a Pdx1/Insulin Dual-Reporter Lentivirus
Authors: Szabat Marta , Luciani Dan S. , Piret James M. , Johnson James D.
Published: December 2008

The enigmatic process of β-cell maturation has significant implications for diabetes pathogenesis, and potential diabetes therapies. This study examined the dynamics and heterogeneity of insulin and pancreatic duodenal homeobox (Pdx)-1 gene expression in adult β-cells. Insulin and Pdx1 expression were monitored in human and mouse islet cells and MIN6 cells using a Pdx1-monomeric red fluorescent protein/insulin-enhanced green fluorescent protein dual-reporter lentivirus. The majority of fluorescent cells were highly positive for both Pdx1 and insulin. Cells expressing Pdx1 but little or no insulin (Pdx1+/Inslow) comprised 15–25% of the total population. Time-lapse imaging demonstrated that Pdx1+/Inslow primary β-cells and MIN6 cells could convert to Pdx1+/Ins+ cells without cell division. Genes involved in the mature β-cell phenotype (Glut2, MafA) were expressed at higher levels in Pdx1+/Ins+ cells relative to Pdx1+/Inslow cells. Conversely, genes implicated in early β-cell development (MafB, Nkx2.2) were enriched in Pdx1+/Inslow cells. Sorted Pdx1+/Inslow MIN6 cells had a higher replication rate and secreted less insulin relative to double-positive cells. Long-term phenotype tracking of Pdx1+/Inslow cells showed two groups, one that matured into Pdx1+/Ins+ cells and one that remained immature. These results demonstrate that adult β-cells pass through distinct maturation states, which is consistent with previously observed heterogeneity in insulin and Pdx1 expression in adult β-cells. At a given time, a proportion of adult β-cells share similar characteristics to functionally immature embryonic β-cell progenitors. The maturation of adult β-cells recapitulates development in that Pdx1 expression precedes the robust expression of insulin and other mature β-cell genes. These results have implications for harnessing the maturation process for therapeutic purposes.
Disruption of Tubulobulbar Complex by High Intratesticular Estrogens Leading to Failed Spermiation
Authors: D'Souza Ryan , Pathak Shilpa , Upadhyay Rahul , Gaonkar Reshma , D'Souza Serena , Sonawane Shobha , Gill-Sharma Manjit , Balasinor Nafisa H.
Published: December 2008

Spermiation is the final phase of spermatogenesis leading to release of mature spermatids into the lumen of the seminiferous tubules. Morphologically, it involves a series of events, namely removal of excess spermatid cytoplasm, removal of ectoplasmic specialization, formation of tubulobulbar complex, and final disengagement of the spermatid from the Sertoli cell. Previous studies in our laboratory have shown that administration of 17β-estradiol at a dose of 100 μg/kg body weight for 10 d resulted in failure of spermiation. This was accompanied by a suppression of FSH and intratesticular testosterone with a concomitant rise in intratesticular 17β-estradiol. The present study was undertaken to determine the cause of failure and subsequently the molecular events in spermiation. Electron microscopic and confocal studies revealed an absence of tubulobulbar complex in step 19 spermatids after estradiol treatment, highlighting the significance of these structures in spermiation. It was further observed that treatment affected the Sertoli cell cytoskeleton and Arp2/3 complex that is critical for de novo polymerization of actin during tubulobulbar complex formation. In conclusion, the present study reports the role of 17β-estradiol in inhibiting the formation of tubulobulbar complex, which could be one of the mechanism by which environmental estrogens influence male fertility.
Postnatal Stress in Birds: A Novel Model of Glucocorticoid Programming of the Hypothalamic-Pituitary-Adrenal Axis
Authors: Spencer Karen A. , Evans Neil P. , Monaghan Patricia
Published: December 2008

There is growing international interest in how environmental conditions experienced during development can shape adult phenotypes and the extent to which such induced changes are adaptive. One physiological system that links an individual to changes in environmental circumstances during development is the hypothalamic-pituitary-adrenal axis. Mammalian studies have linked early postnatal stress to later changes in the hypothalamic-pituitary-adrenal axis; however, the physiological link [lactational corticosterone (CORT) transfer] between mother and offspring during postnatal development constrains the ability to determine the direct effects of such stressors on subsequent physiology and behavior. Here we present a novel model using an avian species, the zebra finch (Taeniopygia guttata), in which maternal hormonal transfer during postnatal development is likely to be absent. Postnatal exposure of chicks to the stress hormone CORT was manipulated for a 16-d period up until nutritional independence (28 d), and the long-term effects on the physiological response to stress determined. CORT doses were scaled to mimic the physiological response of juvenile birds to a capture-handling-restraint protocol. CORT-fed birds showed exaggerated and prolonged responses to acute stress at 60 d of age. Our results clearly demonstrate that postnatal stress has significant long-term effects on the physiological stress response in birds and provides a potential mechanism underlying long-term behavioural responses to developmental conditions. This study represents the first direct evidence for postnatal glucocorticoid programming of the stress response using this novel model for postnatal stress. This model therefore provides an important tool with which to investigate the role of glucocorticoids in shaping adult phenotypes.