bluuebunny/crossref_metadata_2025 huggingface dataset:
Circadian Stage-Dependent Inhibition of Human Breast Cancer Metabolism and Growth by the Nocturnal Melatonin Signal: Consequences of Its Disruption by Light at Night in Rats and Women
Authors: Blask David E. , Dauchy Robert T. , Brainard George C. , Hanifin John P.
Published: December 2009

The circadian production of melatonin by the pineal gland during the night provides an inhibitory signal to tissue-isolated steroid receptor SR+ and — MCF-7 human breast cancer xenografts in female nude rats. A pivotal mechanism for melatonin’s anticancer effects in vivo involves a melatonin receptor-mediated inhibition of linoleic acid (LA) uptake and its metabolism to mitogenically active 13-hydroxyoctadecadienoic acid (13-HODE). Exposure of (SR-) xenograft-bearing rats to increasing intensities of polychromatic white light at night suppresses melatonin while increasing tumor growth rates, DNA content, [3H]thymidine incorporation into DNA, LA uptake, 13-HODE formation, cAMP levels and ERK1/2 activation a dose-dependent manner. Similar effects occur in SR- human breast cancer xenografts perfused in situ with melatonin-depleted blood from healthy female subjects after their exposure to a single bright intensity (2800 lux) of polychromatic light at night. Additionally, SR- human breast cancer xenografts exhibit robust circadian rhythms of LA uptake, 13-HODE formation and proliferative activity. Exposure of xenograft-bearing rats to dim light at night results in the complete elimination of these rhythms which culminates in unfettered, high rates of tumor metabolism and growth. The organization of tumor metabolism and growth within circadian time structure by the oncostatic melatonin signal helps create a balance between the cancer and its host that is disrupted by host exposure to light at night. This biological mechanism may partially explain the higher risk of breast and other cancers in women working rotating night shifts and possibly others who also experience prolonged exposure to light at night.
Molecular Mechanisms of Melatonin Anticancer Effects
Authors: Hill Steven M. , Frasch Tripp , Shulin Xiang  , Lin Yuan  , Duplessis Tamika , Lulu Mao
Published: December 2009

The authors have shown that, via activation of its MT1 receptor, melatonin modulates the transcriptional activity of various nuclear receptors and the proliferation of both ERα+ and ERα- human breast cancer cells. Employing dominant-negative (DN) and dominant-positive (DP) G proteins, it was demonstrated that Gα i2 proteins mediate the suppression of estrogen-induced ERα transcriptional activity by melatonin, whereas the Gαq proteins mediate the enhancement of retinoid-induced RARα transcriptional activity by melatonin. In primary human breast tumors, the authors’ studies demonstrate an inverse correlation between ERα and MT1 receptor expression, and confocal microscopic studies demonstrate that the MT1I receptor is localized to the caveoli and that its expression can be repressed by estrogen and melatonin. Melatonin, via activation of its MT1 receptor, suppresses the development and growth of breast cancer by regulation of growth factors, regulation of gene expression, regulation of clock genes, inhibition of tumor cell invasion and metastasis, and even regulation of mammary gland development. The authors have previously reported that the clock gene, Period 2 ( Per2), is not expressed in human breast cancer cells but that its reexpression in breast cancer cells results in increased expression of p53 and induction of apoptosis. The authors demonstrate that melatonin, via repression of RORα transcriptional activity, blocks the expression of the clock gene BMAL1 . Melatonin’s blockade of BMAL1 expression is associated with the decreased expression of SIRT1, a member of the Silencing Information Regulator family and a histone and protein deacetylase that inhibits the expression of DNA repair enzymes (p53, BRCA1 & 2, and Ku70) and the expression of apoptosis-associated genes. Finally, the authors developed an MMTV-MT1-flag mammary knock-in transgenic mouse that displays reduced ductal branching, ductal epithelium proliferation, and reduced terminal end bud formation during puberty and pregnancy. Lactating female MT1 transgenic mice show a dramatic reduction in the expression of β-casein and whey acidic milk proteins. Further analyses showed significantly reduced ERα expression in mammary glands of MT1 transgenic mice. These results demonstrate that the MT1 receptor is a major transducer of melatonin’s actions in the breast, suppressing mammary gland development and mediating the anticancer actions of melatonin through multiple pathways.
Health Care Access Among Latinos: Implications for Social and Health Care Reforms
Authors: Pérez-Escamilla Rafael
Published: December 2009

According to the Institute of Medicine, health care access is defined as “the degree to which people are able to obtain appropriate care from the health care system in a timely manner.” Two key components of health care access are medical insurance and having access to a usual source of health care. Recent national data show that 34% of Latino individuals do not have health insurance and 27% do not have access to a usual source of health care. This article identifies barriers and solutions for improving health care access among Latino individuals.
Mexican American Adolescents’ Perceptions of a Pro-College Culture
Authors: Castillo Linda G. , Conoley Collie W. , Cepeda Lisa M. , Ivy Karen K. , Archuleta Debra J.
Published: December 2009

Three focus groups of ninth-grade Méxican American students explored the factors contributing to a pro-college culture. The students participated in the federal initiative program called “Gaining Early Awareness and Readiness for Undergraduate Programs.” Analysis revealed specific student, family, peer, and school personnel influences toward a pro-college culture. The focus groups allowed for examining differences between the groups of students at varying risk of not attending college. Implications for school personnel are discussed.
The Impact of Acculturation on Hispanic Students’ Learning Styles
Authors: Gonyea Nathan E.
Published: December 2009

The present study investigated the impact of acculturation on the learning styles of 151 Hispanic students enrolled in a Hispanic Serving Institution in South Texas, controlling for age, gender, and country of origin. Acculturation did not significantly predict learning style when controlling for these three variables. These results may be because of a lack of association between acculturation and learning style or differential acculturation in the sociopersonal and educational realms.
Citizenship, College Degrees, and Occupational Outcomes: Comparison of Latino Immigrants and U.S. Natives at the Turn of the Century
Authors: Flores Stella , Southern Kyle G.
Published: December 2009

Using data from the American Community Survey of the U.S. Census from 2000 to 2007, we analyze the occupational distribution of Latino immigrants and their associated prestige ranking by degree status in comparison with U.S.-born Latinos. We find dramatic gaps in the occupational distribution and prestige rankings among Latinos with similar postsecondary attainment levels by citizenship status.
Retaining Mexican American Special Education Teachers in Texas
Authors: López-Estrada Verónica , Koyama Michelle
Published: December 2009

Although there have been numerous studies addressing factors that cause special education teachers to leave the classroom, few have focused on factors that contribute to teachers remaining in the field for 5 years or more. This study examines the factors that contribute to the retention of Mexican American special education teachers in the lower Rio Grande Valley, geographically located in the southernmost region of Texas.
Your Second Selves
Authors: Kafai Yasmin B. , Fields Deborah A. , Cook Melissa S.
Published: December 2009

Avatars in online games and worlds are seen as players’ key representations in interactions with each other. In this article, we investigate the avatar design and identity play within a large-scale tween virtual world called Whyville.net, with more than 1.5 million registered players of ages 8—16. One unique feature of Whyville is the players’ ability to customize their avatars with various face parts and accessories, all designed and sold by other players in Whyville. Our findings report on the expressive resources available for avatar construction, individual tween players’ choices and rationales in creating their avatars, and online postings about avatar design in the community at large. With the growing interest in player-generated content for online worlds such as Second Life, our discussion will address the role of avatars in identity play and self-representation as well as the social issues that arise within the game world.
‘‘Blacks Deserve Bodies Too!’’: Design and Discussion About Diversity and Race in a Tween Virtual World
Authors: Kafai Yasmin B. , Cook Melissa S. , Fields Deborah A.
Published: December 2009

In this paper, we investigate racial diversity in avatar design and public discussions about race within a large-scale tween virtual world called Whyville.net, with more than 1.5 million registered players of ages 8—16. One unique feature of Whyville is the player’s ability to customize their avatars with various face parts and accessories, all designed and sold by other players in Whyville. Our findings report on the racial diversity of available resources for avatar construction and online postings about the role of race in avatar design and social interactions in the community. With the growing interest in player-generated content for online worlds such as Teen Second Life, our discussion addresses the role of avatars in teen/tween identity development and self-representation, and the role of virtual entrepreneurs and community activists in increasing the diversity of avatar parts available.
‘‘Stealing From Grandma’’ or Generating Cultural Knowledge?
Authors: Fields Deborah A. , Kafai Yasmin B.
Published: December 2009

Much research has described the various practices needed of gaining access and participation in multi-user game communities. Cheat sites are a continuation of game communities where players engage in knowledge building about game related challenges. In this paper we analyze the cheat sites created by players for a tween virtual world called Whyville.net, which encourages youth to participate in a range of social activities and play casual science games. Through analysis we created typologies for both the cheats and sites related to science content. Further, a case study of an exemplary cheat site elaborates on how some player-generated sites work to build knowledge of Whyville. Finally, investigation of over a hundred player-written articles illuminates how Whyvillians contest different practices of cheating and how cheating affects the virtual world. Implications of these findings as cultural artifacts of the game community and as guides for designing informal online learning activities are discussed.
World of Whyville
Authors: Kafai Yasmin B.
Published: December 2009

Virtual worlds have become the new playground for millions of tweens but we know little what it takes to become a player in a virtual community. This paper focuses on one virtual world, called Whyville.net, which at the time of our study hosted over 1.2 million players ages 8 to16 years, with the average player 12.3 years old. Girls represent over 68% of all players. A guided tour to the various places in Whyville, the different types of science games, and the range of players’ activities provides insights into what players talk about, with whom they socialize, what they like to play, and how they engage in investigations. In 2005, a group of researchers set out to study Whyville by recruiting hundreds of participants online and offline in classrooms and after school clubs and by conducting observations, surveys, and interviews about their online activities. In addition, we collected log files that captured their online movements and chat interaction during a six month period. We discuss ethical issues of conducting research as adults in tween virtual communities and limitations of capturing the complexities of interactions simultaneously in online and offline spaces. The paper concludes with an overview of following papers in the special issue that cover players’ avatar designs, representation of race, cheating practices, learning how to throw virtual mudballs, and participation in virtual epidemic.
Investigating the ‘‘Why’’ in Whypox
Authors: Kafai Yasmin B. , Quintero Maria , Feldon David
Published: December 2009

Learning scientists have created and used virtual worlds to support players’ historical, scientific, and ecological inquiries. Much less explored has been the impact of community events on players’ investigations in virtual worlds. The authors present here the case of a community event Whypox, a virtual epidemic whose annual outbreak in Whyville affects players’ communication and appearance. The authors analyze the different levels of participation ranging from casual to systematic in which players searched out more information about the Whypox, participated in online discussions about its causes and investigated different scenarios with simulations. The discussion examines ethical concerns, the contributions of our findings for the design of such community events, and educational resources in virtual worlds to support informal learning.
Mixed Research as a Tool for Developing Quantitative Instruments
Authors: Onwuegbuzie Anthony J. , Bustamante Rebecca M. , Nelson Judith A.
Published: December 2009

In this methodological article, the authors present a meta-framework—comprising several frameworks and models, as well as multiple research approaches—that they call an Instrument Development and Construct Validation (IDCV) process for optimizing the development of quantitative instruments. Using mixed research techniques, the IDCV contains 10 phases that detail the progression from an interdisciplinary review of the literature to the development of the instrument to the evaluation of the instrument development and construct validation process and product(s). Crossover analyses represent a key mechanism in the IDCV, wherein analysis types from one tradition (e.g., quantitative analysis) are used to analyze data from a different tradition (e.g., qualitative data). Finally, the authors provide a heuristic example of a rigorous way to develop a Likert-format scale.
The Role of Physical Activity Participation in Weight Loss Outcomes Following Weight Loss Surgery
Authors: Evans Ronald K.
Published: December 2009

Weight loss surgery (WLS) is an effective intervention for the reduction of body mass and the resolution of obesity-related comorbidities. Excess weight loss following WLS has been reported in the range of 40% to 78% depending on the surgery type and the follow-up time period. Initial weight loss outcomes and weight loss maintenance have been shown to depend on several factors, including the type of surgical procedure, preexisting comorbidities, and compliance with postoperative medical, nutritional, and behavioral recommendations. One factor that has received limited attention in the scientific literature is the role of physical activity in initial weight loss and maintenance following WLS. Physical activity participation of sufficient frequency, intensity, and duration during both the pre- and postoperative time periods has the potential to reduce surgical complications, enhance weight loss outcomes, and improve physical fitness and overall health following WLS. In addition, physical activity has the potential to improve the quality of postoperative weight loss by enhancing fat mass loss while preserving fat-free mass, thereby minimizing the impact of massive weight loss on metabolic rate. In light of these potential benefits, appropriate interventions should be employed to promote physical activity participation of appropriate frequency, intensity, and duration both before and after WLS.
Clinical Outcomes After Anterior Cruciate Ligament Reconstruction: A Meta-Analysis of Autograft Versus Allograft Tissue
Authors: Tibor Lisa M. , Long Joy L. , Schilling Peter L. , Lilly Ryan J. , Carpenter James E. , Miller Bruce S.
Published: December 2009

Background:

Clinical outcomes of autograft and allograft anterior cruciate ligament (ACL) reconstructions are mixed, with some reports of excellent to good outcomes and other reports of early graft failure or significant donor site morbidity.

Objective:

To determine if there is a difference in functional outcomes, failure rates, and stability between autograft and allograft ACL reconstructions.

Data Sources:

Medline, Cochrane Central Register of Controlled Trials (Evidence Based Medicine Reviews Collection), Cochrane Database of Systematic Reviews, Web of Science, CINAHL, and SPORTDiscus were searched for articles on ACL reconstruction. Abstracts from annual meetings of the American Academy of Orthopaedic Surgeons, American Orthopaedic Society for Sports Medicine, and Arthroscopy Association of North America were searched for relevant studies.

Study Selection:

Inclusion criteria for studies were as follows: primary unilateral ACL injuries, mean patient age less than 41 years, and follow-up for at least 24 months postreconstruction. Exclusion criteria for studies included the following: skeletally immature patients, multiligament injuries, and publication dates before 1990.

Data Extraction:

Joint stability measures included Lachman test, pivot-shift test, KT-1000 arthrometer assessment, and frequency of graft failures. Functional outcome measures included Tegner activity scores, Cincinnati knee scores, Lysholm scores, and IKDC (International Knee Documentation Committee) total scores.

Results:

More than 5000 studies were identified. After full text review of 576 studies, 56 were included, of which only 1 directly compared autograft and allograft reconstruction. Allograft ACL reconstructions were more lax when assessed by the KT-1000 arthrometer. For all other outcome measures, there was no statistically significant difference between autograft and allograft ACL reconstruction. For all outcome measures, there was strong evidence of statistical heterogeneity between studies. The sample size necessary for a randomized clinical trial to detect a difference between autograft and allograft reconstruction varied, depending on the outcome.

Conclusions:

With the current literature, only KT-1000 arthrometer assessment demonstrated more laxity with allograft reconstruction. A randomized clinical trial directly comparing allograft to autograft ACL reconstruction is warranted, but a multicenter study would be required to obtain an adequate sample size.
Massive Rotator Cuff Tear in an Adolescent Athlete: A Case Report
Authors: Turman Kimberly A. , Anderson Mark W. , Miller Mark D.
Published: December 2009

Full-thickness rotator cuff tears in the young athlete are a rare injury. These injuries typically result from an acute traumatic event in a contact athlete, as opposed to overuse injuries more commonly seen in throwing athletes. Acute tears may be initially overlooked, with the symptoms attributed to other, more common causes, such as cuff contusion or brachial plexus neuropraxia (“stinger” or “burner”). If undiagnosed, the tear may progress to an irreparable state at the time of eventual diagnosis. Therefore, rotator cuff tear must be included in the differential for acute shoulder injuries in the young athlete. This article presents a case of an adolescent athlete with a traumatic, massive rotator cuff tear that was diagnosed and managed promptly with excellent outcome.
The Prevalence of Medial Epicondylitis Among Patients With C6 and C7 Radiculopathy
Authors: Lee Aaron Taylor , Lee-Robinson Ayse L.
Published: December 2009

Background:

Medial epicondylitis, or golfer’s/pitcher’s elbow, develops as a result of medial stress overload on the flexor muscles at the elbow and presents as pain at the medial epicondyle. Cervical radiculopathy has been associated with lateral epicondylitis, but few associations between the cervical spine and medial epicondylitis have been made. Researchers propose that there is an association, suggesting that the weakness and imbalance in the elbow flexor and extensor muscles from C6 and C7 radiculopathy allow for easy onset of medial epicondylitis.

Hypothesis:

Medial epicondylitis will present in over half the patients diagnosed with C6 and C7 radiculopathy.

Methodology:

A total of 102 patients initially presenting with upper extremity or neck symptoms were diagnosed with cervical radiculopathy. They were then examined for medial epicondylitis. Data were collected by referring to patient charts from February 2008 until June 2009.

Results:

Fifty-five patients were diagnosed with medial epicondylitis. Of these, 44 had C6 and C7 radiculopathy whereas 11 presented with just C6 radiculopathy.

Conclusion:

Medial epicondylitis presented with cervical radiculopathy in slightly more than half the patients. Weakening of the flexor carpi radialis and pronator teres and imbalance of the flexor and extensor muscles from the C6 and C7 radiculopathy allow for easy onset of medial epicondylitis. Patients with medial epicondylitis should be examined for C6 and C7 radiculopathy to ensure proper treatment. Physicians dealing with golfers, pitchers, or other patients with medial epicondylitis should be aware of the association between these 2 diagnoses to optimize care.
Autosomal dominant and sporadic monocytopenia with susceptibility to mycobacteria, fungi, papillomaviruses, and myelodysplasia
Authors: Vinh Donald C. , Patel Smita Y. , Uzel Gulbu , Anderson Victoria L. , Freeman Alexandra F. , Olivier Kenneth N. , Spalding Christine , Hughes Stephen , Pittaluga Stefania , Raffeld Mark , Sorbara Lynn R. , Elloumi Houda Z. , Kuhns Douglas B. , Turner Maria L. , Cowen Edward W. , Fink Danielle , Long-Priel Debra , Hsu Amy P. , Ding Li , Paulson Michelle L. , Whitney Adeline R. , Sampaio Elizabeth P. , Frucht David M. , DeLeo Frank R. , Holland Steven M.
Published: December 2009

We identified 18 patients with the distinct clinical phenotype of susceptibility to disseminated nontuberculous mycobacterial infections, viral infections, especially with human papillomaviruses, and fungal infections, primarily histoplasmosis, and molds. This syndrome typically had its onset in adulthood (age range, 7-60 years; mean, 31.1 years; median, 32 years) and was characterized by profound circulating monocytopenia (mean, 13.3 cells/μL; median, 14.5 cells/μL), B lymphocytopenia (mean, 9.4 cells/μL; median, 4 cells/μL), and NK lymphocytopenia (mean, 16 cells/μL; median, 5.5 cells/μL). T lymphocytes were variably affected. Despite these peripheral cytopenias, all patients had macrophages and plasma cells at sites of inflammation and normal immunoglobulin levels. Ten of these patients developed 1 or more of the following malignancies: 9 myelodysplasia/leukemia, 1 vulvar carcinoma and metastatic melanoma, 1 cervical carcinoma, 1 Bowen disease of the vulva, and 1 multiple Epstein-Barr virus+ leiomyosarcoma. Five patients developed pulmonary alveolar proteinosis without mutations in the granulocyte-macrophage colony-stimulating factor receptor or anti–granulocyte-macrophage colony-stimulating factor autoantibodies. Among these 18 patients, 5 families had 2 generations affected, suggesting autosomal dominant transmission as well as sporadic cases. This novel clinical syndrome links susceptibility to mycobacterial, viral, and fungal infections with malignancy and can be transmitted in an autosomal dominant pattern.
Duffy antigen receptor for chemokines (Darc) polymorphism regulates circulating concentrations of monocyte chemoattractant protein-1 and other inflammatory mediators
Authors: Schnabel Renate B. , Baumert Jens , Barbalic Maja , Dupuis Josée , Ellinor Patrick T. , Durda Peter , Dehghan Abbas , Bis Joshua C. , Illig Thomas , Morrison Alanna C. , Jenny Nancy S. , Keaney John F. , Gieger Christian , Tilley Cathy , Yamamoto Jennifer F. , Khuseyinova Natalie , Heiss Gerardo , Doyle Margaret , Blankenberg Stefan , Herder Christian , Walston Jeremy D. , Zhu Yanyan , Vasan Ramachandran S. , Klopp Norman , Boerwinkle Eric , Larson Martin G. , Psaty Bruce M. , Peters Annette , Ballantyne Christie M. , Witteman Jacqueline C. M. , Hoogeveen Ron C. , Benjamin Emelia J. , Koenig Wolfgang , Tracy Russell P.
Published: December 2009

To identify the genetic basis of circulating concentrations of monocyte chemoattractant protein-1 (MCP-1), we conducted genome-wide association analyses for MCP-1 in 3 independent cohorts (n = 9598). The strongest association was for serum MCP-1 with a nonsynonymous polymorphism, rs12075 (Asp42Gly) in DARC, the gene for Duffy antigen receptor for chemokines, a known vascular reservoir of proinflammatory cytokines (minor allele frequency, 45.6%; P < 1.0 * 10−323). This association was supported by family-based genetic linkage at a locus encompassing the DARC gene (genome-wide P = 8.0 * 10−13). Asp42Gly accounted for approximately 20% of the variability in serum MCP-1 concentrations and also was associated with serum concentrations of interleukin-8 and RANTES. While exploring a lack of association between this polymorphism and EDTA plasma MCP-1 concentrations (P = .82), we determined that both clotting and exogenous heparan sulfate (unfractionated heparin) released substantial amounts of MCP-1 from Darc. Quantitative immunoflow cytometry failed to identify meaningful Asp42Gly-associated differences in Darc expression, suggesting that a functional change is responsible for the differential cytokine binding. We conclude that Asp42Gly is a major regulator of erythrocyte Darc-mediated cytokine binding and thereby the circulating concentrations of several proinflammatory cytokines. We have also identified for the first time 2 mechanisms for the release of reservoir chemokines with possible clinical implications.
Fluid shear stress stimulates phosphorylation-dependent nuclear export of HDAC5 and mediates expression of KLF2 and eNOS
Authors: Wang Weiye , Ha Chang Hoon , Jhun Bong Sook , Wong Chelsea , Jain Mukesh K. , Jin Zheng-Gen
Published: December 2009

Fluid shear stress generated by steady laminar blood flow protects vessels from atherosclerosis. Krüppel-like factor 2 (KLF2) and endothelial nitric oxide synthase (eNOS) are fluid shear stress–responsive genes and key mediators in flow anti-inflammatory and antiatherosclerotic actions. However, the molecular mechanisms underlying flow induction of KLF2 and eNOS remain largely unknown. Here, we show a novel role of histone deacetylase 5 (HDAC5) in flow-mediated KLF2 and eNOS expression. We found for the first time that fluid shear stress stimulated HDAC5 phosphorylation and nuclear export in endothelial cells through a calcium/calmodulin-dependent pathway. Consequently, flow induced the dissociation of HDAC5 and myocyte enhancer factor-2 (MEF2) and enhanced MEF2 transcriptional activity, which leads to expression of KLF2 and eNOS. Adenoviral overexpression of a HDAC5 phosphorylation–defective mutant (Ser259/Ser498 were replaced by Ala259/Ala498, HDAC5-S/A), which shows resistance to flow-induced nuclear export, suppressed flow-mediated MEF2 transcriptional activity and expression of KLF2 and eNOS. Importantly, HDAC5-S/A attenuated the flow-inhibitory effect on monocyte adhesion to endothelial cells. Taken together, our results reveal that phosphorylation-dependent derepression of HDAC5 mediates flow-induced KLF2 and eNOS expression as well as flow anti-inflammation, and suggest that HDAC5 could be a potential therapeutic target for the prevention of atherosclerosis.
Intrathymic transplantation of bone marrow–derived progenitors provides long-term thymopoiesis
Authors: Vicente Rita , Adjali Oumeya , Jacquet Chantal , Zimmermann Valérie S. , Taylor Naomi
Published: December 2009

The sustained differentiation of T cells in the thymus cannot be maintained by resident intrathymic (IT) precursors and requires that progenitors be replenished from the bone marrow (BM). In patients with severe combined immunodeficiency (SCID) treated by hematopoietic stem cell transplantation, late T-cell differentiation defects are thought to be due to an insufficient entry of donor BM progenitors into the thymus. Indeed, we find that the intravenous injection of BM progenitors into nonconditioned ζ-chain–associated protein kinase 70 (ZAP-70)–deficient mice with SCID supports short- but not long-term thymopoiesis. Remarkably, we now show that the IT administration of these progenitors produces a significant level of donor-derived thymopoiesis for more than 6 months after transplantation. In contrast to physiologic thymopoiesis, long-term donor thymopoiesis was not due to the continued recruitment of progenitors from the BM. Rather, IT transplantation resulted in the unique generation of a large population of early c-Kithigh donor precursors within the thymus. These ZAP-70–deficient mice that received an IT transplant had a significantly increased prothymocyte niche compared with their untreated counterparts; this phenotype was associated with the generation of a medulla. Thus, IT administration of BM progenitors results in the filling of an expanded precursor niche and may represent a strategy for enhancing T-cell differentiation in patients with SCID.
Oxidative stress–specific interaction between FANCD2 and FOXO3a
Authors: Li Jie , Du Wei , Maynard Suzette , Andreassen Paul R. , Pang Qishen
Published: December 2009

The molecular pathway by which Fanconi anemia (FA) proteins function in oxidative stress response has not been defined. Here we report the functional interaction of the FA protein Fanconi anemia complementation group D2 (FANCD2) and the forkhead transcription factor forkhead box O 3a (FOXO3a). FOXO3a colocalized with FANCD2 foci in response to oxidative stress. The FANCD2-FOXO3a complex was not detected in cells deficient for the FA core complex component FANCA but could be restored in corrected cells. Consistent with this, a nonmonoubiquitinated FANCD2 mutant failed to bind FOXO3a. Although both mitomycin C and ionizing radiation induced FANCD2 monoubiquitination, neither could induce the association of FANCD2 and FOXO3a. Overexpression of FOXO3a reduced abnormal accumulation of reactive oxygen species, enhanced cellular resistance to oxidative stress, and increased antioxidant gene expression in corrected but not mutant FA-D2 cells. The novel oxidative stress response pathway identified in this study, in which FANCD2 and FOXO3a converge, probably contributes to cellular antioxidant defense.
Allogeneic T regulatory cell–mediated transplantation tolerance in adoptive therapy depends on dominant peripheral suppression and central tolerance
Authors: Adeegbe Dennis , Levy Robert B. , Malek Thomas R.
Published: December 2009

T regulatory cells (Tregs) represent agents to mediate tolerance to allografts so that the use of immunosuppressive drugs is avoided. In this regard, we previously demonstrated that the adoptive transfer of allogeneic Tregs into IL-2Rβ−/− mice prevented autoimmunity and led to allograft tolerance. Here, we investigated the requirements and mechanisms that favor this long-lasting tolerance. The most potent tolerance required exact matching of all alloantigens between the adoptively transferred allogeneic Tregs and allogeneic skin grafts, but tolerance to such allografts that lacked expression of major histocompatibility complex class I or II molecules also occurred. Thus, Tregs are not required to directly recognize major histocompatibility complex class II alloantigens to suppress skin transplant rejection. Depletion of allogeneic Tregs substantially, but not completely, abrogated this form of tolerance. However, thymocytes from allogeneic Treg adoptively transferred IL-2Rβ−/− mice did not reject the corresponding allogeneic skin graft in secondary Scid recipients. Consistent with a requirement for a deletional mechanism in this IL-2Rβ−/− model, a small number of wild-type T cells readily abrogated the immune tolerant state. Collectively, these findings indicate that full tolerance induction is largely dependent on substantial Treg-mediated suppression and thymic deletion of alloreactive T cells and may represent general conditions for Treg-mediated transplantation tolerance.
Graft-versus-host disease: regulation by microbe-associated molecules and innate immune receptors
Authors: Penack Olaf , Holler Ernst , van den Brink Marcel R. M.
Published: December 2009

Acute graft-versus-host disease (GVHD) remains the major obstacle to a more favorable therapeutic outcome of allogeneic hematopoietic stem cell transplantation (HSCT). GVHD is characterized by tissue damage in gut, liver, and skin, caused by donor T cells that are critical for antitumor and antimicrobial immunity after HSCT. One obstacle in combating GVHD used to be the lack of understanding the molecular mechanisms that are involved in the initiation phase of this syndrome. Recent research has demonstrated that interactions between microbial-associated molecules (pathogen-associated molecular patterns [PAMPs]) and innate immune receptors (pathogen recognition receptors [PRRs]), such as NOD-like receptors (NLRs) and Toll-like receptors (TLRs), control adaptive immune responses in inflammatory disorders. Polymorphisms of the genes encoding NOD2 and TLR4 are associated with a higher incidence of GVHD in HSC transplant recipients. Interestingly, NOD2 regulates GVHD through its inhibitory effect on antigen-presenting cell (APC) function. These insights identify important mechanisms regarding the induction of GVHD through the interplay of microbial molecules and innate immunity, thus opening a new area for future therapeutic approaches. This review covers current knowledge of the role of PAMPs and PRRs in the control of adaptive immune responses during inflammatory diseases, particularly GVHD.
Human rhinovirus and coronavirus detection among allogeneic hematopoietic stem cell transplantation recipients
Authors: Milano Filippo , Campbell Angela P. , Guthrie Katherine A. , Kuypers Jane , Englund Janet A. , Corey Lawrence , Boeckh Michael
Published: December 2009

Little is known about clinical and virologic manifestations of rhinovirus (HRV) and coronavirus (HCoV) infections after hematopoietic cell transplantation (HCT). We performed surveillance for 1 year and describe the natural history of these infections during the first 100 days after allogeneic HCT, when symptom surveys and upper respiratory samples were collected weekly. Samples were tested using RT-PCR for HRVs and HCoVs (OC43, 229E, HKU1, and NL63). Among 215 patients, 64 (30%) patients had 67 infections. Day 100 cumulative incidence estimate was 22.3% for HRV and 11.1% for HCoV. Median duration of viral shedding was 3 weeks; prolonged shedding of at least 3 months occurred in 6 of 45 patients with HRV and 3 of 22 with HCoV. Six patients with HRV and 9 with HCoV were asymptomatic. HRV infection was associated with rhinorrhea, congestion, postnasal drip, sputum, and cough; HCoV infection was not associated with respiratory symptoms or hepatic dysfunction. Lower respiratory infection developed in 2 patients with HRV before day 100, and 1 each with HRV and HCoV after day 100. HRV and HCoV infections are common in the first 100 days after HCT, viral shedding lasts more than 3 weeks in half, and lower respiratory infection is rare.
Endothelin receptor antagonist and airway dysfunction in pulmonary arterial hypertension
Authors: Droste Annette S , Rohde David , Voelkers Mirko , Filusch Arthur , Bruckner Thomas , Borst Mathias M , Katus Hugo A , Meyer F Joachim
Published: December 2009

Background

In idiopathic pulmonary arterial hypertension (IPAH), peripheral airway obstruction is frequent. This is partially attributed to the mediator dysbalance, particularly an excess of endothelin-1 (ET-1), to increased pulmonary vascular and airway tonus and to local inflammation. Bosentan (ET-1 receptor antagonist) improves pulmonary hemodynamics, exercise limitation, and disease severity in IPAH. We hypothesized that bosentan might affect airway obstruction.

Methods

In 32 IPAH-patients (19 female, WHO functional class II (n = 10), III (n = 22); (data presented as mean ± standard deviation) pulmonary vascular resistance (11 ± 5 Wood units), lung function, 6 minute walk test (6-MWT; 364 ± 363.7 (range 179.0-627.0) m), systolic pulmonary artery pressure, sPAP, 79 ± 19 mmHg), and NT-proBNP serum levels (1427 ± 2162.7 (range 59.3-10342.0) ng/L) were measured at baseline, after 3 and 12 months of oral bosentan (125 mg twice per day).

Results and Discussion

At baseline, maximal expiratory flow at 50 and 25% vital capacity were reduced to 65 ± 25 and 45 ± 24% predicted. Total lung capacity was 95.6 ± 12.5% predicted and residual volume was 109 ± 21.4% predicted. During 3 and 12 months of treatment, 6-MWT increased by 32 ± 19 and 53 ± 69 m, respectively; p < 0.01; whereas sPAP decreased by 7 ± 14 and 10 ± 19 mmHg, respectively; p < 0.05. NT-proBNP serum levels tended to be reduced by 123 ± 327 and by 529 ± 1942 ng/L; p = 0.11). There was no difference in expiratory flows or lung volumes during 3 and 12 months.

Conclusion

This study gives first evidence in IPAH, that during long-term bosentan, improvement of hemodynamics, functional parameters or serum biomarker occur independently from persisting peripheral airway obstruction.
The acidic domains of the Toc159 chloroplast preprotein receptor family are intrinsically disordered protein domains
Authors: Richardson Lynn GL , Jelokhani-Niaraki Masoud , Smith Matthew D
Published: December 2009

Background

The Toc159 family of proteins serve as receptors for chloroplast-destined preproteins. They directly bind to transit peptides, and exhibit preprotein substrate selectivity conferred by an unknown mechanism. The Toc159 receptors each include three domains: C-terminal membrane, central GTPase, and N-terminal acidic (A-) domains. Although the function(s) of the A-domain remains largely unknown, the amino acid sequences are most variable within these domains, suggesting they may contribute to the functional specificity of the receptors.

Results

The physicochemical properties of the A-domains are characteristic of intrinsically disordered proteins (IDPs). Using CD spectroscopy we show that the A-domains of two Arabidopsis Toc159 family members (atToc132 and atToc159) are disordered at physiological pH and temperature and undergo conformational changes at temperature and pH extremes that are characteristic of IDPs.

Conclusions

Identification of the A-domains as IDPs will be important for determining their precise function(s), and suggests a role in protein-protein interactions, which may explain how these proteins serve as receptors for such a wide variety of preprotein substrates.
A service-oriented architecture for integrating the modeling and formal verification of genetic regulatory networks
Authors: Monteiro Pedro T , Dumas Estelle , Besson Bruno , Mateescu Radu , Page Michel , Freitas Ana T , de Jong Hidde
Published: December 2009

Background

The study of biological networks has led to the development of increasingly large and detailed models. Computer tools are essential for the simulation of the dynamical behavior of the networks from the model. However, as the size of the models grows, it becomes infeasible to manually verify the predictions against experimental data or identify interesting features in a large number of simulation traces. Formal verification based on temporal logic and model checking provides promising methods to automate and scale the analysis of the models. However, a framework that tightly integrates modeling and simulation tools with model checkers is currently missing, on both the conceptual and the implementational level.

Results

We have developed a generic and modular web service, based on a service-oriented architecture, for integrating the modeling and formal verification of genetic regulatory networks. The architecture has been implemented in the context of the qualitative modeling and simulation tool GNA and the model checkers NU SMV and CADP. GNA has been extended with a verification module for the specification and checking of biological properties. The verification module also allows the display and visual inspection of the verification results.

Conclusions

The practical use of the proposed web service is illustrated by means of a scenario involving the analysis of a qualitative model of the carbon starvation response in E. coli. The service-oriented architecture allows modelers to define the model and proceed with the specification and formal verification of the biological properties by means of a unified graphical user interface. This guarantees a transparent access to formal verification technology for modelers of genetic regulatory networks.
The powdery mildew resistance gene REN1 co-segregates with an NBS-LRR gene cluster in two Central Asian grapevines
Authors: Coleman Courtney , Copetti Dario , Cipriani Guido , Hoffmann Sarolta , Kozma Pál , Kovács László , Morgante Michele , Testolin Raffaele , Di Gaspero Gabriele
Published: December 2009

Background

Grape powdery mildew is caused by the North American native pathogenErysiphe necator. EurasianVitis viniferavarieties were all believed to be susceptible.REN1is the first resistance gene naturally found in cultivated plants ofVitis vinifera.

Results

REN1is present in 'Kishmish vatkana' and 'Dzhandzhal kara', two grapevines documented in Central Asia since the 1920's. These cultivars have a second-degree relationship (half sibs, grandparent-grandchild, or avuncular), and share by descent the chromosome on which the resistance alleleREN1is located. TheREN1interval was restricted to 1.4 cM using 38 SSR markers distributed across the locus and the segregation of the resistance phenotype in two progenies of collectively 461 offspring, derived from either resistant parent. The boundary markers delimit a 1.4-Mbp sequence in the PN40024 reference genome, which contains 27 genes with known functions, 2 full-length coiled-coil NBS-LRR genes, and 9 NBS-LRR pseudogenes. In theREN1locus of PN40024, NBS genes have proliferated through a mixture of segmental duplications, tandem gene duplications, and intragenic recombination between paralogues, indicating that theREN1locus has been inherently prone to producing genetic variation. Three SSR markers co-segregate withREN1, the outer ones confining the 908-kb array of NBS-LRR genes. Kinship and clustering analyses based on genetic distances with susceptible cultivars representative of Central AsianVitis viniferaindicated that 'Kishmish vatkana' and 'Dzhandzhal kara' fit well into local germplasm. 'Kishmish vatkana' also has a parent-offspring relationship with the seedless table grape 'Sultanina'. In addition, the distant genetic relatedness to rootstocks, some of which are derived from North American species resistant to powdery mildew and have been used worldwide to guard against phylloxera since the late 1800's, argues againstREN1being infused intoVitis viniferafrom a recent interspecific hybridisation.

Conclusion

TheREN1gene resides in an NBS-LRR gene cluster tightly delimited by two flanking SSR markers, which can assist in the selection of this DNA block in breeding betweenVitis viniferacultivars. TheREN1locus has multiple layers of structural complexity compared with its two closely related paralogous NBS clusters, which are located some 5 Mbp upstream and 4 Mbp downstream of theREN1interval on the same chromosome.
Transcriptional adaptations following exercise in Thoroughbred horse skeletal muscle highlights molecular mechanisms that lead to muscle hypertrophy
Authors: McGivney Beatrice A , Eivers Suzanne S , MacHugh David E , MacLeod James N , O'Gorman Grace M , Park Stephen DE , Katz Lisa M , Hill Emmeline W
Published: December 2009

Background

Selection for exercise-adapted phenotypes in the Thoroughbred racehorse has provided a valuable model system to understand molecular responses to exercise in skeletal muscle. Exercise stimulates immediate early molecular responses as well as delayed responses during recovery, resulting in a return to homeostasis and enabling long term adaptation. Global mRNA expression during the immediate-response period has not previously been reported in skeletal muscle following exercise in any species. Also, global gene expression changes in equine skeletal muscle following exercise have not been reported. Therefore, to identify novel genes and key regulatory pathways responsible for exercise adaptation we have used equine-specific cDNA microarrays to examine global mRNA expression in skeletal muscle from a cohort of Thoroughbred horses (n =8) at three time points (before exercise, immediately post-exercise, and four hours post-exercise) following a single bout of treadmill exercise.

Results

Skeletal muscle biopsies were taken from thegluteus mediusbefore (T0), immediately after (T1) and four hours after (T2) exercise. Statistically significant differences in mRNA abundance between time points (T0vsT1and T0vsT2) were determined using the empirical Bayes moderatedt-test in the Bioconductor package Linear Models for Microarray Data (LIMMA) and the expression of a select panel of genes was validated using real time quantitative reverse transcription PCR (qRT-PCR). While only two genes had increased expression at T1(P< 0.05), by T2932 genes had increased (P< 0.05) and 562 genes had decreased expression (P< 0.05). Functional analysis of genes differentially expressed during the recovery phase (T2) revealed an over-representation of genes localized to the actin cytoskeleton and with functions in the MAPK signalling, focal adhesion, insulin signalling, mTOR signaling, p53 signaling and Type II diabetes mellitus pathways. At T1, using a less stringent statistical approach, we observed an over-representation of genes involved in the stress response, metabolism and intracellular signaling. These findings suggest that protein synthesis, mechanosensation and muscle remodeling contribute to skeletal muscle adaptation towards improved integrity and hypertrophy.

Conclusions

This is the first study to characterize global mRNA expression profiles in equine skeletal muscle using an equine-specific microarray platform. Here we reveal novel genes and mechanisms that are temporally expressed following exercise providing new knowledge about the early and late molecular responses to exercise in the equine skeletal muscle transcriptome.