bluuebunny/crossref_metadata_2025_split huggingface dataset:
Orchestrating osteogenic differentiation of mesenchymal stem cells—identification of placental growth factor as a mechanosensitive gene with a pro-osteogenic role
Authors: McCoy Ryan J. , Widaa Amro , Watters Karen M. , Wuerstle Maximilian , Stallings Ray L. , Duffy Garry P. , O'Brien Fergal J. 
Published: July 2013

AbstractSkeletogenesis is initiated during fetal development and persists through adult life as either a remodeling process in response to homeostatic regulation or as a regenerative process in response to physical injury. Mesenchymal stem cells (MSCs) play a crucial role providing progenitor cells from which osteoblasts, bone matrix forming cells are differentiated. The mechanical environment plays an important role in regulating stem cell differentiation into osteoblasts, however, the mechanisms by which MSCs respond to mechanical stimuli are yet to be fully elucidated. To increase understanding of MSC mechanotransuction and osteogenic differentiation, this study aimed to identify novel, mechanically augmented genes and pathways with pro-osteogenic functionality. Using collagen glycoaminoglycan scaffolds as mimics of native extracellular matrix, to create a 3D environment more representative of that found in bone, MSC-seeded constructs were mechanically stimulated in a flow-perfusion bioreactor. Global gene expression profiling techniques were used to identify potential candidates warranting further investigation. Of these, placental growth factor (PGF) was selected and expression levels were shown to strongly correlate to both the magnitude and duration of mechanical stimulation. We demonstrated that PGF gene expression was modulated through an actin polymerization-mediated mechanism. The functional role of PGF in modulating MSC osteogenic differentiation was interrogated, and we showed a concentration-dependent response whereby low concentrations exhibited the strongest pro-osteogenic effect. Furthermore, pre-osteoclast migration and differentiation, as well as endothelial cell tubule formation also maintained concentration-dependent responses to PGF, suggesting a potential role for PGF in bone resorption and angiogenesis, processes key to bone remodeling and fracture repair.
Mesenchymal stem cells inhibit cutaneous radiation-induced fibrosis by suppressing chronic inflammation
Authors: Horton Jason A. , Hudak Kathryn E. , Chung Eun Joo , White Ayla O. , Scroggins Bradley T. , Burkeen Jeffrey F. , Citrin Deborah E. 
Published: July 2013

Abstract
Exposure to ionizing radiation (IR) can result in the development of cutaneous fibrosis, for which few therapeutic options exist. We tested the hypothesis that bone marrow-derived mesenchymal stem cells (BMSC) would favorably alter the progression of IR-induced fibrosis. We found that a systemic infusion of BMSC from syngeneic or allogeneic donors reduced skin contracture, thickening, and collagen deposition in a murine model. Transcriptional profiling with a fibrosis-targeted assay demonstrated increased expression of interleukin-10 (IL-10) and decreased expression of IL-1β in the irradiated skin of mice 14 days after receiving BMSC. Similarly, immunoassay studies demonstrated durable alteration of these and several additional inflammatory mediators. Immunohistochemical studies revealed a reduction in infiltration of proinflammatory classically activated CD80+ macrophages and increased numbers of anti-inflammatory regulatory CD163+ macrophages in irradiated skin of BMSC-treated mice. In vitro coculture experiments confirmed that BMSC induce expression of IL-10 by activated macrophages, suggesting polarization toward a regulatory phenotype. Furthermore, we demonstrated that tumor necrosis factor-receptor 2 (TNF-R2) mediates IL-10 production and transition toward a regulatory phenotype during coculture with BMSC. Taken together, these data demonstrate that systemic infusion of BMSC can durably alter the progression of radiation-induced fibrosis by altering macrophage phenotype and suppressing local inflammation in a TNF-R2-dependent fashion.
Cyclin D3 critically regulates the balance between self-renewal and differentiation in skeletal muscle stem cells
Authors: Luca Giulia , Ferretti Roberta , Bruschi Marco , Mezzaroma Eleonora , Caruso Maurizia 
Published: July 2013

Abstract
Satellite cells are mitotically quiescent myogenic stem cells resident beneath the basal lamina surrounding adult muscle myofibers. In response to injury, multiple extrinsic signals drive the entry of satellite cells into the cell cycle and then to proliferation, differentiation, and self-renewal of their downstream progeny. Because satellite cells must endure for a lifetime, their cell cycle activity must be carefully controlled to coordinate proliferative expansion and self-renewal with the onset of the differentiation program. In this study, we find that cyclin D3, a member of the family of mitogen-activated D-type cyclins, is critically required for proper developmental progression of myogenic progenitors. Using a cyclin D3-knockout mouse we determined that cyclin D3 deficiency leads to reduced myofiber size and impaired establishment of the satellite cell population within the adult muscle. Cyclin D3-null myogenic progenitors, studied ex vivo on isolated myofibers and in vitro, displayed impaired cell cycle progression, increased differentiation potential, and reduced self-renewal capability. Similarly, silencing of cyclin D3 in C2 myoblasts caused anticipated exit from the cell cycle and precocious onset of terminal differentiation. After induced muscle damage, cyclin D3-null myogenic progenitors exhibited proliferation deficits, a precocious ability to form newly generated myofibers and a reduced capability to repopulate the satellite cell niche at later stages of the regeneration process. These results indicate that cyclin D3 plays a cell-autonomous and nonredundant function in regulating the dynamic balance between proliferation, differentiation, and self-renewal that normally establishes an appropriate pool size of adult satellite cells.
Dysfunction of Endothelial Progenitor Cells from Smokers and Chronic Obstructive Pulmonary Disease Patients Due to Increased DNA Damage and Senescence
Authors: Paschalaki Koralia E. , Starke Richard D. , Hu Yanhua , Mercado Nicolas , Margariti Andriana , Gorgoulis Vassilis G. , Randi Anna M. , Barnes Peter J. 
Published: July 2013

Abstract
Cardiovascular disease (CVD) is a major cause of death in smokers, particularly in those with chronic obstructive pulmonary disease (COPD). Circulating endothelial progenitor cells (EPC) are required for endothelial homeostasis, and their dysfunction contributes to CVD. To investigate EPC dysfunction in smokers, we isolated and expanded blood outgrowth endothelial cells (BOEC) from peripheral blood samples from healthy nonsmokers, healthy smokers, and COPD patients. BOEC from smokers and COPD patients showed increased DNA double-strand breaks and senescence compared to nonsmokers. Senescence negatively correlated with the expression and activity of sirtuin-1 (SIRT1), a protein deacetylase that protects against DNA damage and cellular senescence. Inhibition of DNA damage response by silencing of ataxia telangiectasia mutated (ATM) kinase resulted in upregulation of SIRT1 expression and decreased senescence. Treatment of BOEC from COPD patients with the SIRT1 activator resveratrol or an ATM inhibitor (KU-55933) also rescued the senescent phenotype. Using an in vivo mouse model of angiogenesis, we demonstrated that senescent BOEC from COPD patients are dysfunctional, displaying impaired angiogenic ability and increased apoptosis compared to cells from healthy nonsmokers. Therefore, this study identifies epigenetic regulation of DNA damage and senescence as pathogenetic mechanisms linked to endothelial progenitors' dysfunction in smokers and COPD patients. These defects may contribute to vascular disease and cardiovascular events in smokers and could therefore constitute therapeutic targets for intervention. Stem Cells 2013;31:2813–2826
Is There an Appropriate Balance Between the Number of Solar and Space Physics PhDs and the Jobs Available?
Authors: Moldwin Mark B. , Torrence John , Moldwin Lauren A. , Morrow Cherilynn 
Published: July 2013

Key Points

The first demographic survey of Solar and Space Physics (S&SP) was conducted
Annual number of PhD awarded in S&SP has doubled over the last decade
Annual number of jobs advertised in S&SP have decreased in recent years
Computational approaches for understanding energy metabolism
Authors: Shestov Alexander A. , Barker Brandon , Gu Zhenglong , Locasale Jason W. 
Published: July 2013

There has been a surge of interest in understanding the regulation of metabolic networks involved in disease in recent years. Quantitative models are increasingly being used to interrogate the metabolic pathways that are contained within this complex disease biology. At the core of this effort is the mathematical modeling of central carbon metabolism involving glycolysis and the citric acid cycle (referred to as energy metabolism). Here, we discuss several approaches used to quantitatively model metabolic pathways relating to energy metabolism and discuss their formalisms, successes, and limitations. WIREs Syst Biol Med 2013, 5:733–750. doi: 10.1002/wsbm.1238This article is categorized under:

Analytical and Computational Methods > Computational Methods
Models of Systems Properties and Processes > Mechanistic Models
Biological Mechanisms > Metabolism
Robotic Endocrine Surgery: State of the Art
Authors: Taskin Halit Eren , Arslan Naciye Cigdem , Aliyev Shamil , Berber Eren 
Published: July 2013

Abstract
Over the last decade, developments in technology have led a rapid progress in robotic endocrine surgery applications. Robotics is attractive to the surgeon because of the three‐dimensional image quality, articulating instruments, and stable surgical platform. Safety and effectiveness of robotic adrenalectomy and thyroidectomy have been shown in many studies. While these robotic procedures offer better ergonomics for the surgeon, they provide similar outcomes compared to the laparoscopic approach for adrenalectomy and better cosmetic results versus the conventional option for thyroidectomy. Recently, while the robotic approach for adrenalectomy has been popularized, enthusiasm for robotic thyroidectomy has decreased. In the present review we aim to describe emerging robotic procedures and review the literature regarding outcomes.
Quality Improvement Activities for Surgical Services at District Hospitals in Developing Countries and Perceived Barriers to Quality Improvement: Findings From Ghana and the Scientific Literature
Authors: Choo Shelly , Papandria Dominic , Goldstein Seth D. , Perry Henry , Hesse Afua A. J. , Abatanga Francis , Abdullah Fizan 
Published: July 2013

AbstractBackgroundMost quality improvement (QI) activities in developing countries, established with funds from external donors, are focused on specific diseases or outreach programs, such as family planning or child survival. District hospitals in developing countries serve as the primary entry point for patients with surgical problems in developing countries, yet little is known about the extent to which formal QI activities for surgical services are present in these settings or the perceptions of hospital staff about the barriers to improving quality in this setting. This study aimed to document surgical QI efforts at district hospitals and perceived barriers to improving quality in a developing country—Ghana. It also provides a summary of the existing published scientific literature concerning surgical QI in developing countries.MethodsA survey team visited 10 government district hospitals in Ghana, one in each of Ghana’s 10 regions. The number and type of QI activities (surgical and nonsurgical) at these district hospitals and the perspectives of hospital staff regarding the steps required to improve the quality of surgical services in their facility were recorded.ResultsOf the 10 hospitals assessed, nine reported having some type of QI activity, ranging from satisfaction surveys to assessing quality of infection prevention. Only one hospital reported having QI activity addressing surgical care. To improve the quality of surgical care, seven hospitals reported the need for trained specialists in surgery, obstetrics, and gynecology. Six cited the need for an appropriately equipped operating theater and recovery ward. The primary barrier to achieving these recommendations, cited by 70 % of the hospitals, was the inability to recruit and retain qualified specialists with surgical skills.ConclusionsFor Ghana to improve significantly the quality of surgical care provided in its district hospitals, greater emphasis is needed for continuous, systematic QI monitoring and for solving the problems identified. Increasing the number of appropriately trained surgical care providers is essential to strengthen the quality of surgical services in district hospitals. These findings likely apply to other resource‐limited countries as well. Increased attention to improving the quality of surgical services at district hospitals in developing countries is urgently needed.
Ontogenetic timing of density dependence: location‐specific patterns reflect distribution of a limiting resource
Authors: Teichert Maxim A. K. , Einum Sigurd , Finstad Anders G. , Ugedal Ola , Forseth Torbjørn 
Published: July 2013

AbstractTheoretical considerations suggest that the relative abundance of age‐specific limiting resources determines the ontogenetic timing of density dependence. Structural shelters may represent one such resource which can become increasingly scarce with increasing body size. Here we use a time series of juvenile Atlantic salmon (Salmo salar) densities and ask whether ontogenetic patterns of density‐dependent losses in two separate reaches of a river can be predicted by considering their shelter abundances. The analyses were conducted using sampling site data (n= 30) as well as stream‐reach averages. Loss rates from the egg to the young‐of‐the‐year stage were density‐dependent in both reaches. For the transition from the young‐of‐the‐year to the yearling stage, when shelters are more likely to become limiting, the results were sensitive to the spatial scale of analysis. On the reach scale, among‐year variation in loss rates was positively correlated with density in the reach with the lowest shelter abundance, whereas no such effect was found in the other reach. This demonstrates that the ontogenetic timing of density dependence can vary among areas within populations, and hence among populations, and that this variation can be explained by quantification of age‐specific limiting factors. For analyses at the sample site scale this pattern was reversed, with stronger density dependence in the reach with highest shelter abundance. However, this result was clearly driven by immigration into low density sites, which masked the true reach‐level effect. Thus, our study also exemplifies how population level regulation inferred from patch‐ or trap‐based data that fails to account for animal movements can be biased.
Cross-pollination benefits differ among oilseed rape varieties
Authors: HUDEWENZ A. , PUFAL G. , BÖGEHOLZ A-L. , KLEIN A-M. 
Published: July 2013

SUMMARYWinter oilseed rape (Brassica napus) is an important crop for human consumption and biofuel production and its production is increasing worldwide. It is generally assumed that cross-pollination by insects increases oilseed rape yield but testing of this has been restricted to a few rapeseed varieties and produced varying results. The present study determines whether cross-pollination benefits a number of oilseed rape varieties by comparing yield in the presence and absence of insects. Four rapeseed varieties (Sherlock, Traviata, Treffer and Visby) were used with ten individuals each in four pollination treatments: (1) supplementary hand-pollination, (2) open pollination with insects able to access the flowers, (3) wind pollination and (4) autonomous self-pollination. Across all four varieties, open and supplementary hand-pollination treatments resulted in higher fruit set, numbers of seeds per pod and seed yield compared with wind and self-pollination. The cross-pollination benefits, however, differed among rapeseed varieties: Treffer and Visby had a higher dependence on open (insects) and supplementary cross-pollination than Sherlock and Traviata. Across all four varieties, seed weight compensated for reduced fruit set and was highest when plants were self-pollinated. The present results highlight the importance of considering varietal differences in crop pollination research. Information on the pollination requirements of crop varieties is required by farmers to optimize management decisions in a world of increasing agropollination deficits.
On taxing wildlife films and exposure to nature
Authors: Wunder Sven , Sheil Douglas 
Published: July 2013

AbstractSome conservation finance strategies feature taxes on nature's benign, and arguably educational, uses. This applies to a recent proposal to extract payment from producers of nature films and also to past efforts to raise entrance fees to protected areas. We argue that, as they are currently formulated, it is misleading to label these proposals as payments for environmental service schemes, as they lack voluntary and conditional payments. Rather, they are a form of taxation. Such revenue-seeking measures may prove to be short-sighted. They will raise prices and curtail the demand for those environmental services that embody some element of education, thus reducing public exposure to nature. This could diminish public awareness, curb people's biophilia and devalue Nature's ‘existence values’. This drive for more conservation cash income in the short term could undermine a broad, long-term societal basis for conservation and its future financing.
Effect of plasma channel non-uniformity on resonant third harmonic generation
Authors: Panwar Anuraj , Ryu Chang-Mo , Kumar Ashok 
Published: July 2013

AbstractWe study the generation of resonant third harmonic laser radiation in a density non-uniform rippled plasma channel. An introduction of plasma channel non-uniformity strongly enhances the self-focusing and compression of main laser pulse at lower powers. In a deeper plasma channel, self-focusing is less sensitive to laser amplitude variation but increases compression. Plasma density ripple ‘nq’ leading to resonant third harmonic generation when kq = 4ω2p/3meω0cγ0, where ‘ω’p is electron plasma frequency, ‘ω0’ is laser frequency, and ‘γ0’ is the electron Lorentz factor. Third harmonic is produced through the beating of ponderomotive force induced second harmonic density oscillations and the oscillatory velocity of electrons at main laser frequency. The self-focusing and compression of the fundamental pulse periodically enhances the intensity of the third-harmonic pulse at lower powers of main laser. In a deeper plasma channel, the third harmonic power is less effective by self-focusing and the compression of main laser, and increase with main laser pulse power.
Evaluation of left ventricular volumes in the early neonatal period using three-dimensional echocardiography
Authors: Nagasawa Hiroyuki 
Published: July 2013

AbstractBackgroundAwareness about normal cardiac volumes in the neonatal period is very important for understanding the cardiac function; however, the small cardiac size of neonates makes it difficult to perform invasive examinations. Three-dimensional echocardiography is used to evaluate cardiac volumes in children. However, no studies using this method have examined left ventricular volumes in neonates during the early neonatal period.MethodsThe study group consisted of 255 normal neonates. Comparisons of the stroke volume calculated according to the velocity–time integral and Pombo method were made.ResultsThe volumes in both end-diastole and end-systole and the stroke volume gradually decreased over time after birth. Participants with continuous a persistent ductus arteriosus flow had higher stroke volumes than those without persistent ductus arteriosus. The average end-diastolic volume per body surface area (m2) was 30.61 ml/m2 in boys and 29.80 ml/m2 in girls, whereas the ventricular end-systolic volume was 12.89 ml/m2 in boys and 12.80 ml/m2 in girls among the participants without persistent ductus arteriosus. The average stroke volume was 17.70 ml/m2 in boys and 17.00 ml/m2 in girls. Statistically significant gender differences were observed in the end-diastolic volume (p = 0.0053), stroke volume (p < 0.0001), and ejection fraction (p = 0.039). The cardiac index was calculated to be 2.04 L/minute/m2 in boys and 1.95 L/minute/m2 in girls, which was significantly lower than that calculated using the velocity–time integral and Pombo method (p < 0.0001).ConclusionsSignificant gender differences in the end-diastolic volume, stroke volume, and ejection fraction at birth were revealed. The cardiac index in the early neonatal period was found to be relatively smaller than what had previously been recognised.
Hypertrophic cardiomyopathy: prognostic factors and survival analysis in 128 Egyptian patients
Authors: El-Saiedi Sonia A. , Seliem Zeinab S. , Esmail Reem I. 
Published: July 2013

AbstractBackground: Hypertrophic cardiomyopathy is an important cause of disability and death in patients of all ages. Egyptian children may differ from Western and Asian patients in the pattern of hypertrophy distribution, clinical manifestations, and risk factors. Objectives: The aim of our study was to report the clinical characteristics and outcomes of Egyptian children with hypertrophic cardiomyopathy studied over a 7-year duration and to determine whether the reported adult risk factors for sudden cardiac death are predictive of the outcome in these affected children. Study design and methods: This retrospective study included 128 hypertrophic cardiomyopathy children. The data included personal history, family history, physical examination, baseline laboratory measurements, electrocardiogram, and Holter and echocardiographic results. Logistic regression analysis was used for the detection of risk factors of death. Results: Fifty-one out of 128 patients died during the period of the study. Of the 51 deaths, 36 (70.5%) occurred in patients presenting before 1 year of age. Only eight patients had surgical intervention. Extreme left ventricular hypertrophy, that is, interventricular septal wall thickness or posterior wall thickness Z-score >6, sinus tachycardia, and supraventricular tachycardia were found to be independent risk factors for prediction of death in patients with hypertrophic cardiomyopathy. Conclusions: At our Egyptian tertiary care centre, hypertrophic cardiomyopathy has a relatively worse prognosis when compared with reports from Western and Asian series. Infants have a worse outcome than children presenting after the age of 1 year. A poorer prognosis in childhood hypertrophic cardiomyopathy is predicted by an extreme left ventricular hypertrophy, the presence of sinus tachycardia, and supraventricular tachycardia.