bluuebunny/crossref_metadata_2025 huggingface dataset:
QTL mapping in white spruce: gene maps and genomic regions underlying adaptive traits across pedigrees, years and environments
Authors: Pelgas Betty , Bousquet Jean , Meirmans Patrick G , Ritland Kermit , Isabel Nathalie
Published: March 2011

Background

The genomic architecture of bud phenology and height growth remains poorly known in most forest trees. In non model species, QTL studies have shown limited application because most often QTL data could not be validated from one experiment to another. The aim of our study was to overcome this limitation by basing QTL detection on the construction of genetic maps highly-enriched in gene markers, and by assessing QTLs across pedigrees, years, and environments.

Results

Four saturated individual linkage maps representing two unrelated mapping populations of 260 and 500 clonally replicated progeny were assembled from 471 to 570 markers, including from 283 to 451 gene SNPs obtained using a multiplexed genotyping assay. Thence, a composite linkage map was assembled with 836 gene markers.

For individual linkage maps, a total of 33 distinct quantitative trait loci (QTLs) were observed for bud flush, 52 for bud set, and 52 for height growth. For the composite map, the corresponding numbers of QTL clusters were 11, 13, and 10. About 20% of QTLs were replicated between the two mapping populations and nearly 50% revealed spatial and/or temporal stability. Three to four occurrences of overlapping QTLs between characters were noted, indicating regions with potential pleiotropic effects. Moreover, some of the genes involved in the QTLs were also underlined by recent genome scans or expression profile studies.

Overall, the proportion of phenotypic variance explained by each QTL ranged from 3.0 to 16.4% for bud flush, from 2.7 to 22.2% for bud set, and from 2.5 to 10.5% for height growth. Up to 70% of the total character variance could be accounted for by QTLs for bud flush or bud set, and up to 59% for height growth.

Conclusions

This study provides a basic understanding of the genomic architecture related to bud flush, bud set, and height growth in a conifer species, and a useful indicator to compare with Angiosperms. It will serve as a basic reference to functional and association genetic studies of adaptation and growth in Picea taxa. The putative QTNs identified will be tested for associations in natural populations, with potential applications in molecular breeding and gene conservation programs. QTLs mapping consistently across years and environments could also be the most important targets for breeding, because they represent genomic regions that may be least affected by G × E interactions.
Association between Frequency Domain Heart Rate Variability and Unplanned Readmission to Hospital in Geriatric Patients
Authors: Chiang Jui-Kun , Fu Chin-Hua , Kuo Terry BJ , Koo Malcolm
Published: March 2011

Background

An accurate prediction of unplanned readmission (UR) after discharge from hospital can facilitate physician's decision making processes for providing better quality of care in geriatric patients. The objective of this study was to explore the association of cardiac autonomic functions as measured by frequency domain heart rate variability (HRV) and 14-day UR in geriatric patients.

Methods

Patients admitted to the geriatric ward of a regional hospital in Chiayi county in Taiwan were followed prospectively from July 2006 to June 2007. Those with invasive tubes and those who were heavy smokers, heavy alcohol drinkers, on medications that might influence HRV, or previously admitted to the hospital within 30 days were excluded. Cardiac autonomic functions were evaluated by frequency domain indices of HRV. Multiple logistic regression was used to assess the association between UR and HRV indices adjusted for age and length of hospitalization.

Results

A total of 78 patients met the inclusion criteria and 15 of them were readmitted within 14 days after discharge. The risk of UR was significantly higher in patients with lower levels of total power (OR = 1.39; 95% CI = 1.04-2.00), low frequency power (LF) (OR = 1.22; 95% CI = 1.03-1.49), high frequency power (HF) (OR = 1.27; 95% CI = 1.02-1.64), and lower ratios of low frequency power to high frequency power (LF/HF ratio) (OR = 1.96; 95% CI = 1.07-3.84).

Conclusion

This is the first study to evaluate the association between frequency domain heart rate variability and the risk of UR in geriatric patients. Frequency domain heart rate variability indices measured on admission were significantly associated with increased risk of UR in geriatric patients. Additional studies are required to confirm the value and feasibility of using HRV indices on admission as a non-invasive tool to assist the prediction of UR in geriatric patients.
Environmentally persistent free radicals induce airway hyperresponsiveness in neonatal rat lungs
Authors: Balakrishna Shrilatha , Saravia Jordy , Thevenot Paul , Ahlert Terry , Lominiki Slawo , Dellinger Barry , Cormier Stephania A
Published: March 2011

Background

Increased asthma risk/exacerbation in children and infants is associated with exposure to elevated levels of ultrafine particulate matter (PM). The presence of a newly realized class of pollutants, environmentally persistent free radicals (EPFRs), in PM from combustion sources suggests a potentially unrecognized risk factor for the development and/or exacerbation of asthma.

Methods

Neonatal rats (7-days of age) were exposed to EPFR-containing combustion generated ultrafine particles (CGUFP), non-EPFR containing CGUFP, or air for 20 minutes per day for one week. Pulmonary function was assessed in exposed rats and age matched controls. Lavage fluid was isolated and assayed for cellularity and cytokines andin vivoindicators of oxidative stress. Pulmonary histopathology and characterization of differential protein expression in lung homogenates was also performed.

Results

Neonates exposed to EPFR-containing CGUFP developed significant pulmonary inflammation, and airway hyperreactivity. This correlated with increased levels of oxidative stress in the lungs. Using differential two-dimensional electrophoresis, we identified 16 differentially expressed proteins between control and CGUFP exposed groups. In the rats exposed to EPFR-containing CGUFP; peroxiredoxin-6, cofilin1, and annexin A8 were upregulated.

Conclusions

Exposure of neonates to EPFR-containing CGUFP induced pulmonary oxidative stress and lung dysfunction. This correlated with alterations in the expression of various proteins associated with the response to oxidative stress and the regulation of glucocorticoid receptor translocation in T lymphocytes.
Pancreatitis, very early compared with normal start of enteral feeding (PYTHON trial): design and rationale of a randomised controlled multicenter trial
Authors: Bakker Olaf J , van Santvoort Hjalmar C , van Brunschot Sandra , Ahmed Ali Usama , Besselink Marc G , Boermeester Marja A , Bollen Thomas L , Bosscha Koop , Brink Menno A , Dejong Cornelis H , van Geenen Erwin J , van Goor Harry , Heisterkamp Joos , Houdijk Alexander P , Jansen Jeroen M , Karsten Thom M , Manusama Eric R , Nieuwenhuijs Vincent B , van Ramshorst Bert , Schaapherder Alexander F , van der Schelling George P , Spanier Marcel BM , Tan Adriaan , Vecht Juda , Weusten Bas L , Witteman Ben J , Akkermans Louis M , Gooszen Hein G ,   the Dutch Pancreatitis Study Group
Published: March 2011

Background

In predicted severe acute pancreatitis, infections have a negative effect on clinical outcome. A start of enteral nutrition (EN) within 24 hours of onset may reduce the number of infections as compared to the current practice of starting an oral diet and EN if necessary at 3-4 days after admission.

Methods/Design

The PYTHON trial is a randomised controlled, parallel-group, superiority multicenter trial. Patients with predicted severe acute pancreatitis (Imrie-score ≥ 3 or APACHE-II score ≥ 8 or CRP > 150 mg/L) will be randomised to EN within 24 hours or an oral diet and EN if necessary, after 72 hours after hospital admission.

During a 3-year period, 208 patients will be enrolled from 20 hospitals of the Dutch Pancreatitis Study Group. The primary endpoint is a composite of mortality or infections (bacteraemia, infected pancreatic or peripancreatic necrosis, pneumonia) during hospital stay or within 6 months following randomisation. Secondary endpoints include other major morbidity (e.g. new onset organ failure, need for intervention), intolerance of enteral feeding and total costs from a societal perspective.

Discussion

The PYTHON trial is designed to show that a very early (< 24 h) start of EN reduces the combined endpoint of mortality or infections as compared to the current practice of an oral diet and EN if necessary at around 72 hours after admission for predicted severe acute pancreatitis.

Trial Registration

ISRCTN: ISRCTN18170985
Endoscopic application of n-butyl-2-cyanoacrylate on esophagojejunal anastomotic leak: a case report
Authors: Pramateftakis Manousos-Georgios , Vrakas Georgios , Kanellos Ioannis , Mantzoros Ioannis , Angelopoulos Stamatis , Eleftheriades Efthymios , Lazarides Charalampos
Published: March 2011

Introduction

This case report describes an esophagojejunal anastomotic leak following total gastrectomy for gastric cancer. The leak was treated successfully with endoscopic application of n-butyl-2-cyanoacrylate. This is the first case report on the endoscopic application of cyanoacrylate alone for the treatment of an anastomotic leak.

Case presentation

This report describes a case of a 68-year-old Caucasian man who underwent surgery for gastric cancer. He underwent total gastrectomy and esophagojejunal anastomosis with Roux-en-Y anastomosis plus transverse colectomy. An anastomotic leak was treated conservatively at first for a total of three weeks. However, the leak persisted; therefore, the decision was made to apply topical endoscopic n-butyl-2-cyanoacrylate.

Conclusion

The endoscopic application of n-butyl-2-cyanoacrylate alone can be used successfully to treat esophagojejunal anastomotic leakage.
Rapamycin potentiates cytotoxicity by docetaxel possibly through downregulation of Survivin in lung cancer cells
Authors: Niu Huiyan , Wang Jiahe , Li Hui , He Ping
Published: March 2011

Background

To elucidate whether rapamycin, the inhibitor of mTOR (mammalian target of rapamycin), can potentiate the cytotoxic effect of docetaxel in lung cancer cells and to probe the mechanism underlying such enhancement.

Methods

Lung cancer cells were treated with docetaxel and rapamycin. The effect on the proliferation of lung cancer cells was evaluated using the MTT method, and cell apoptosis was measured by flow cytometry. Protein expression and level of phosphorylation were assayed using Western Blot method.

Results

Co-treatment of rapamycin and docetaxel was found to favorably enhance the cytotoxic effect of docetaxel in four lung cancer cell lines. This tumoricidal boost is associated with a reduction in the expression and phosphorylation levels of Survivin and ERK1/2, respectively.

Conclusion

The combined application of mTOR inhibitor and docetaxel led to a greater degree of cancer cell killing than that by either compound used alone. Therefore, this combination warrants further investigation in its suitability of serving as a novel therapeutic scheme for treating advanced and recurrent lung cancer patients.
Acute and critically ill peripartum cardiomyopathy and 'bridge to' therapeutic options: a single center experience with intra-aortic balloon pump, extra corporeal membrane oxygenation and continuous-flow left ventricular assist devices
Authors: Gevaert Sofie , Van Belleghem Yves , Bouchez Stefaan , Herck Ingrid , De Somer Filip , De Block Yasmina , Tromp Fiona , Vandecasteele Els , Martens Floor , De Pauw Michel
Published: March 2011

Introduction

Peripartum cardiomyopathy (PPCM) patients refractory to medical therapy and intra-aortic balloon pump (IABP) counterpulsation or in whom weaning from these therapies is impossible, are candidates for a left ventricular assist device (LVAD) as a bridge to recovery or transplant. Continuous-flow LVADs are smaller, have a better long-term durability and are associated with better outcomes. Extra corporeal membrane oxygenation (ECMO) can be used as a temporary support in patients with refractory cardiogenic shock. The aim of this study was to evaluate the efficacy and safety of mechanical support in acute and critically ill PPCM patients.

Methods

This was a retrospective search of the patient database of the Ghent University hospital (2000 to 2010).

Results

Six PPCM-patients were treated with mechanical support. Three patients presented in the postpartum period and three patients at the end of pregnancy. All were treated with IABP, the duration of IABP support ranged from 1 to 13 days. An ECMO was inserted in one patient who presented with cardiogenic shock, multiple organ dysfunction syndrome and a stillborn baby. Two patients showed partial recovery and could be weaned off the IABP. Four patients were implanted with a continuous-flow LVAD (HeartMate II®, Thoratec Inc.), including the ECMO-patient. Three LVAD patients were successfully transplanted 78, 126 and 360 days after LVAD implant; one patient is still on the transplant waiting list. We observed one peripheral thrombotic complication due to IABP and five early bleeding complications in three LVAD patients. One patient died suddenly two years after transplantation.

Conclusions

In PPCM with refractory heart failure IABP was safe and efficient as a bridge to recovery or as a bridge to LVAD. ECMO provided temporary support as a bridge to LVAD, while the newer continuous-flow LVADs offered a safe bridge to transplant.
Stable P-wave modeling for reverse-time migration in tilted TI media
Authors: Duveneck Eric , Bakker Peter M.
Published: March 2011

We present an approach for P-wave modeling in inhomogeneous transversely isotropic media with tilted symmetry axis (TTI media), suitable for anisotropic reverse-time migration. The proposed approach is based on wave equations derived from first principles — the equations of motion and Hooke’s law — under the acoustic TI approximation. Consequently, no assumptions are made about the spatial variation of medium parameters. A rotation of the stress and strain tensors to a local coordinate system, aligned with the TI-symmetry axis, makes it possible to benefit from the simple and sparse form of the TI-elastic tensor in that system. The resulting wave equations can be formulated either as a set of five first-order or as a set of two second-order partial differential equations. For the constant-density case, the second-order TTI wave equations involve mixed and nonmixed second-order spatial derivatives with respect to global, nonrotated coordinates. We propose a numerical implementation of these equations using high-order centered finite differences. To minimize modeling artifacts related to the use of centered first-derivative operators, we use discrete second-derivative operators for the nonmixed second-order spatial derivatives and repeated discrete first-derivative operators for the mixed derivatives. Such a combination of finite-difference operators leads to a stable wave propagator, provided that the operators are designed properly. In practice, stability is achieved by slightly weighting down terms that contain mixed derivatives. This has a minor, practically negligible, effect on the kinematics of wave propagation. The stability of the presented scheme in inhomogeneous TTI models with rapidly varying anisotropic symmetry axis direction is demonstrated with numerical examples.
Seismic attribute illumination of an igneous reservoir in China
Authors: Zhang Kui , Marfurt Kurt J. , Wan Zhonghong , Zhan Shifan
Published: March 2011

When lava flows and pyroclastic deposits exhibit sufficient porosity and permeability, extrusive igneous rocks have the potential to host large hydrocarbon accumulations. The porosity in these deposits can come from either vesicular porosity, or from secondary porosity that resulted from later fracturing and hydrothermal alteration. Recent studies (Feng, 2008) show that significant hydrocarbon reserves are contained in volcanic rocks in China which are primarily found in the Songliao, Bohai Bay, and Erlian basins. These hydrocarbon-rich reservoirs range from upper Jurassic to Tertiary in age.
An introduction to this special section: Shales
Authors: Hart Bruce , Sayers Colin M. , Jackson Alan
Published: March 2011

Traditionally, mudstones (shales) have been of interest to the petroleum industry because they form seals or source rocks. In geophysical circles, mudstones have also been of interest because their sometimes pronounced velocity anisotropy can lead to imaging problems and because of overpressures that can be defined by other types of velocity anomalies. Only within the past decade, and due largely to advances in drilling and stimulation techniques, have mudstones been seriously regarded as reservoirs in their own right. Although mudstones form approximately 70% of sedimentary rocks, much remains to be learned about these fine-grained rocks. For example:
Stress-induced versus lithological anisotropy in compacted claystones and soft shales
Authors: Holt Rune M. , Bhuiyan Mohammad H. , Kolstø Morten I. , Bakk Audun , Stenebraten Jørn F. , Fjær Erling
Published: March 2011

Shales are anisotropic. Most definitions of shale in-corporate this attribute, either by referring to fissility and existence of cleavage planes, or to anisotropic texture resulting in anisotropy of physical properties on many length scales. Definitions of shale scatter though; some focus on a high content of clay minerals as characteristic of a shale, while others consider a large amount of fine grains (< 2μm) as sufficient. In a rock mechanical context, it is natural to define shale as a rock in which clay minerals constitute the load-bearing framework. This means that “gas shales” in oil-field terminology are, strictly speaking, not shales according to a geological or a geomechanical perspective. Still, these materials have a lot in common with classically defined shales (e.g., low permeability) and anisotropy.
Microseismic hydraulic fracture imaging: The path toward optimizing shale gas production
Authors: Maxwell Shawn
Published: March 2011

Economic shale gas production involves hydraulic fracture stimulation in order to create permeable flow paths within these low-permeability reservoirs. Microseismic monitoring has shown that often these “fracs” consist of complex fracture networks, with large surface contact areas with the reservoir. Optimized production is therefore dependent on the ability of the stimulation to activate an extensive fracture network. Much of the current attention around hydraulic fractures focuses on microseismic imaging of the activated network; however, the path toward optimized shale gas production also requires methods to both predict and model the fracture networks. Along the path, engineers will be able to close the loop for an optimally designed stimulation: being able to predict, monitor, and assess the stimulated fracture network. As an industry, we are just starting down this path, and this paper describes a few case studies that highlight recent advancements. Before we can ultimately predict the fracture network that will result from a specific injection, we first need to understand the factors that control the variability in hydraulic fracture networks that are routinely observed. To this end, two case studies are described integrating microseismic imaging with seismic reservoir characterization, both of which show that the hydraulic fracture geometries are controlled by pre-existing fractures and stresses. Many engineering tools exist to model the performance of a fracture network, and one of the case studies describes a reservoir simulation investigation of the production sensitivity to various ways of characterizing the stimulated hydraulic fracture network. To begin, however, because microseismic is the basis of these case studies and will likely remain the primary hydraulic fracture monitoring technique, some general comments are first made regarding microseismic specific to shale gas.
Psychological Assessment of Primary Aldosteronism: A Controlled Study
Authors: Sonino Nicoletta , Tomba Elena , Genesia Maria Luisa , Bertello Chiara , Mulatero Paolo , Veglio Franco , Fava Giovanni A. , Fallo Francesco
Published: March 2011

Objective:

Our objective was to investigate psychological correlates in a population with primary aldosteronism (PA) using methods found to be sensitive and reliable in psychosomatic research.

Methods:

Twenty-three PA patients (12 male, 11 female; mean age 50 ± 9 yr) were compared with 23 patients with essential hypertension (EH) (15 male, eight female; mean age 47 ± 8 yr) and 23 matched normotensive subjects. A modified version of the Structural Clinical Interview for DSM-IV, a shortened version of the structured interview for the Diagnostic Criteria for Psychosomatic Research, and two self-rating questionnaires, the Psychosocial Index and the Symptom Questionnaire, were administered.

Results:

Twelve of 23 patients with PA (52.2%) suffered from an anxiety disorder compared with four of 23 with EH (17.4%) and one control (4.3%) (P < 0.001). Generalized anxiety disorder was more frequent in PA than in EH patients and controls (P < 0.05). As assessed by Diagnostic Criteria for Psychosomatic Research, irritable mood was more frequent in PA and EH compared with controls (P < 0.05) but did not differentiate PA from EH. According to Psychosocial Index results, patients with PA had higher levels of stress (P < 0.01) and psychological distress (P < 0.01) and lower level of well-being (P < 0.05) than controls. Compared with EH patients, PA patients had higher scores in stress subscale (P < 0.05). The Symptom Questionnaire showed higher levels of anxiety (P < 0.01), depression (P < 0.01) and somatization (P < 0.01) and lower physical well-being (P < 0.05) in PA than controls.

Conclusion:

A role of mineralocorticoid regulatory mechanisms in clinical situations concerned with anxiety and stress is suggested.
Canoe functions at the CNS midline glia in a complex with Shotgun and Wrapper-Nrx-IV during neuron-glia interactions
Authors: Slováková Jana , Carmena Ana
Published: March 2011

Vertebrates and insects alike use glial cells as intermediate targets to guide growing axons. Similar to vertebrate oligodendrocytes, Drosophila midline glia ensheath and separate axonal commissures. Neuron-glia interactions are crucial during these events, although the proteins involved remain largely unknown. Here, we show that Canoe (Cno), the Drosophila ortholog of AF-6, and the DE-cadherin Shotgun (Shg) are highly restricted to the interface between midline glia and commissural axons. cno mutant analysis, genetic interactions and co-immunoprecipitation assays unveil Cno function as a novel regulator of neuron-glia interactions, forming a complex with Shg, Wrapper and Neurexin IV, the homolog of vertebrate Caspr/paranodin. Our results also support additional functions of Cno, independent of adherens junctions, as a regulator of adhesion and signaling events in non-epithelial tissues.
Disruption of a conserved region of Xist exon 1 impairs Xist RNA localisation and X-linked gene silencing during random and imprinted X chromosome inactivation
Authors: Senner Claire E. , Nesterova Tatyana B. , Norton Sara , Dewchand Hamlata , Godwin Jonathan , Mak Winifred , Brockdorff Neil
Published: March 2011

In XX female mammals a single X chromosome is inactivated early in embryonic development, a process that is required to equalise X-linked gene dosage relative to XY males. X inactivation is regulated by a cis-acting master switch, the Xist locus, the product of which is a large non-coding RNA that coats the chromosome from which it is transcribed, triggering recruitment of chromatin modifying factors that establish and maintain gene silencing chromosome wide. Chromosome coating and Xist RNA-mediated silencing remain poorly understood, both at the level of RNA sequence determinants and interacting factors. Here, we describe analysis of a novel targeted mutation, XistINV, designed to test the function of a conserved region located in exon 1 of Xist RNA during X inactivation in mouse. We show that XistINV is a strong hypomorphic allele that is appropriately regulated but compromised in its ability to silence X-linked loci in cis. Inheritance of XistINV on the paternal X chromosome results in embryonic lethality due to failure of imprinted X inactivation in extra-embryonic lineages. Female embryos inheriting XistINV on the maternal X chromosome undergo extreme secondary non-random X inactivation, eliminating the majority of cells that express the XistINV allele. Analysis of cells that express XistINV RNA demonstrates reduced association of the mutant RNA to the X chromosome, suggesting that conserved sequences in the inverted region are important for Xist RNA localisation.
Asymmetric Mbc, active Rac1 and F-actin foci in the fusion-competent myoblasts during myoblast fusion inDrosophila
Authors: Haralalka Shruti , Shelton Claude , Cartwright Heather N. , Katzfey Erin , Janzen Evan , Abmayr Susan M.
Published: March 2011

Myoblast fusion is an intricate process that is initiated by cell recognition and adhesion, and culminates in cell membrane breakdown and formation of multinucleate syncytia. In the Drosophila embryo, this process occurs asymmetrically between founder cells that pattern the musculature and fusion-competent myoblasts (FCMs) that account for the bulk of the myoblasts. The present studies clarify and amplify current models of myoblast fusion in several important ways. We demonstrate that the non-conventional guanine nucleotide exchange factor (GEF) Mbc plays a fundamental role in the FCMs, where it functions to activate Rac1, but is not required in the founder cells for fusion. Mbc, active Rac1 and F-actin foci are highly enriched in the FCMs, where they localize to the Sns:Kirre junction. Furthermore, Mbc is crucial for the integrity of the F-actin foci and the FCM cytoskeleton, presumably via its activation of Rac1 in these cells. Finally, the local asymmetric distribution of these proteins at adhesion sites is reminiscent of invasive podosomes and, consistent with this model, they are enriched at sites of membrane deformation, where the FCM protrudes into the founder cell/myotube. These data are consistent with models promoting actin polymerization as the driving force for myoblast fusion.
Direct in vivo cellular reprogramming involves transition through discrete, non-pluripotent steps
Authors: Richard Jai Prakash , Zuryn Steven , Fischer Nadine , Pavet Valeria , Vaucamps Nadège , Jarriault Sophie
Published: March 2011

Cells can change identity during normal development, in response to tissue damage or defined artificial treatments, or during disease processes such as cancer. Strikingly, not only the reprogramming of tissue cells to an embryonic stem cell-like state, but also the direct conversion from one cell type to another have been described. Direct cell type conversion could represent an alternative strategy for cellular therapies. However, little is known about the actual cellular steps undertaken by a cell as it changes its identity and their possible consequences for the organism. Using an in vivo single-cell system of natural direct reprogramming, in which a C. elegans rectal cell transforms into a motoneuron, we present an in-depth analysis of the cellular transformations involved. We found that the reprogrammed cell transits through intermediate states during direct in vivo reprogramming. We identified and characterised a mutant in the conserved COE transcription factor UNC-3 in which this cellular transformation is blocked. We determined that complete erasure of initial identity first takes place, followed by stepwise, unc-3-dependent, redifferentiation into a motoneuron. Furthermore, unlike in vitro induced reprogramming, reversion to a dedifferentiated identity does not lead to an increase in cellular potential in a natural, in vivo context. Our findings suggest that direct cell type conversion occurs via successive steps, and that dedifferentiation can occur in the absence of cell division. Furthermore, our results suggest that mechanisms are in place in vivo to restrict cell potential during reprogramming, a finding with important implications for regenerative medicine.
Cell type-specific filamin complex regulation by a novel class of HECT ubiquitin ligase is required for normal cell motility and patterning
Authors: Blagg Simone L. , Battom Suzanne E. , Annesley Sarah J. , Keller Thomas , Parkinson Katie , Wu Jasmine M. F. , Fisher Paul R. , Thompson Christopher R. L.
Published: March 2011

Differential cell motility, which plays a key role in many developmental processes, is perhaps most evident in examples of pattern formation in which the different cell types arise intermingled before sorting out into discrete tissues. This is thought to require heterogeneities in responsiveness to differentiation-inducing signals that result in the activation of cell type-specific genes and ‘salt and pepper’ patterning. How differential gene expression results in cell sorting is poorly defined. Here we describe a novel gene (hfnA) that provides the first mechanistic link between cell signalling, differential gene expression and cell type-specific sorting in Dictyostelium. HfnA defines a novel group of evolutionarily conserved HECT ubiquitin ligases with an N-terminal filamin domain (HFNs). HfnA expression is induced by the stalk differentiation-inducing factor DIF-1 and is restricted to a subset of prestalk cells (pstO). hfnA− pstO cells differentiate but their sorting out is delayed. Genetic interactions suggest that this is due to misregulation of filamin complex activity. Overexpression of filamin complex members phenocopies the hfnA− pstO cell sorting defect, whereas disruption of filamin complex function in a wild-type background results in pstO cells sorting more strongly. Filamin disruption in an hfnA− background rescues pstO cell localisation. hfnA− cells exhibit altered slug phototaxis phenotypes consistent with filamin complex hyperactivity. We propose that HfnA regulates filamin complex activity and cell type-specific motility through the breakdown of filamin complexes. These findings provide a novel mechanism for filamin regulation and demonstrate that filamin is a crucial mechanistic link between responses to differentiation signals and cell movement in patterning based on ‘salt and pepper’ differentiation and sorting out.
Use of secondary care in England by international immigrants
Authors: Steventon Adam , Bardsley Martin
Published: March 2011

Objective:

Although over half a million migrants arrive in England each year, information about their use of health services is limited. Our aim was to describe the use of secondary care by international immigrants and compare it to people moving within England.

Methods:

Routine anonymized data were used to identify people who appear as registering with a general practitioner (GP) for the first time in England, yet are aged 15 or over. We assumed that most long-term residents will have registered before the age of 15, and therefore the majority of those registering for the first time later in life will be international immigrants. The study compared hospital admissions among first registrants to the general population of England and to within-England migrants, selected using propensity scoring.

Results:

The first registrants aged 15 or over had around half the rate of hospital admission asthat of the general population of England. They were also less likely to have a hospital admission than a matched group of within-England migrants. The lower admission rates persisted over several years and were consistent in three consecutive cohorts of first registrants (each consisting of over half a million people).

Conclusions:

The assumption that international immigrants use more secondary care than the members of the indigenous population appears to be unfounded.
On finite subgroups of compact Lie groups and fundamental groups of Riemannian manifolds
Authors: Su Xiaole , Wang Yusheng
Published: March 2011

Let G be a compact Lie group of dimension m, and let Γ be any finite subgroup in G. The main result in this paper is that for each m there exists a constant c(m) such that: (i) for connected G, Γ contains an abelian subgroup with index ≤ c (m) which belongs to some torus in G; (ii) for non-connected G, Γ contains a subgroup with index ≤ c(m) which commutes with some torus in G. Using this we get some conclusions on fundamental groups of Riemannian manifolds (especially of positive sectional curvature).
Sets resilient to erosion
Authors: Pegden Wesley
Published: March 2011

The erosion of a set X in Euclidean space by a radius r > 0 is the subset of X consisting of points at distance ≥ r from the complement of X. A set is resilient to erosion if it is similar to its erosion by some positive radius. We give a somewhat surprising characterization of resilient sets, consisting in one part of simple geometric constraints on convex resilient sets, and, in another, a correspondence between nonconvex resilient sets and scale-invariant (e.g., ‘exact fractal’) sets.
Homocysteine: a biomarker in neurodegenerative diseases
Authors: Herrmann Wolfgang , Obeid Rima
Published: March 2011

Diseases of the central nervous system are found in patients with severe hyperhomocysteinemia (HHcy). Epidemiological studies show a positive, dose-dependent relationship between mild-to-moderate increases in plasma total homocysteine concentrations (Hcy) and the risk of neurodegenerative diseases, such as Alzheimer's disease, vascular dementia, cognitive impairment or stroke. HHcy is a surrogate marker for B vitamin deficiency (folate, B12, B6) and a neurotoxic agent. The concept of improving the patient's clinical outcome by lowering of Hcy with B vitamins seems to be attractive. Recent B vitamin supplementation trials demonstrated a slowing of brain atrophy and improvement in some domains of cognitive function. Meta-analysis of secondary prevention trials showed that B vitamins supplementation caused a decrease in plasma Hcy and a trend for lowering the risk of stroke. HHcy is common in elderly people. Therefore, it seems prudent to identify B vitamin deficient subjects and to ensure sufficient vitamin intake. Therefore, recent evidence supports the role of Hcy as a potential biomarker in age-related neurodegenerative diseases.
Polymer-Based Solar Cells: State-of-the-Art Principles for the Design of Active Layer Components
Authors: Thompson Barry C. , Khlyabich Petr P. , Burkhart Beate , Aviles Alejandra E. , Rudenko Andrey , Shultz Ginger V. , Ng Christi F. , Mangubat Lorenzo B.
Published: March 2011

The vision of organic photovoltaics is that of a low cost solar energy conversion platform that provides lightweight, flexible solar cells that are easily incorporated into existing infrastructure with minimal impact on land usage. Polymer solar cells have been a subject of growing research interest over the past quarter century, and are now developed to the point where they are on the verge of introduction into the market. Towards the goal of continuing to improve the performance of polymer solar cells, a number of avenues are being explored. Here, the focus is on optimization of device performance via the development of a more fundamental understanding of device parameters. The fundamental operating principle of an organic solar cell is based on the cooperative interaction of molecular or polymeric electron donors and acceptors. Here the state-of-the-art in understanding of the physical and electronic interactions between donor and acceptor components is examined, as is important for understanding future avenues of research and the ultimate potential of this technology.
Evaluating Food-Fuel Trade-Offs via Market Choice: The Case of Iowa Corn Producers
Authors: Yu Tun-Hsiang , Hart Chad , You Wen
Published: March 2011

This study examines food-fuel trade-offs from the perspective of crop producers and their choices in marketing their grain among food, feed and fuel use. Based on a recent survey of Iowa grain producers, this study finds that price competition from ethanol plants has increased the share of the corn marketed directly to ethanol plants and lowered the market share of corn marketed for domestic and international food/feed purposes. Other factors, such as farm size and market distance, affect the share of corn directed to the fuel, food, and feed markets. The results indicate corn producers are willing to bear higher transportation costs to reach food markets over other market outlets.
Low Band Gap Polymers for Roll-to-Roll Coated Organic Photovoltaics – Design, Synthesis and Characterization
Authors: Bundgaard Eva , Hagemann Ole , Jørgensen Mikkel , Krebs Frederik C.
Published: March 2011

In this paper we present the design and synthesis of 25 new low band gap polymers. The polymers were characterized by UV-vis spectroscopy which showed optical band gaps of 2.0–0.9 eV. The polymers which were soluble enough were applied in organic photovoltaics, both small area devices with a spin coated active layer and in large area modules where all layers including the active layer were either roll-to-roll coated or printed. These experiments showed that the design of polymers compatible with roll-toroll coating is not straightforward and that there are various issues such as donor/acceptor fitting within the polymer, side chains to ensure solubility and HOMO/LUMO level alignment with the acceptor (e.g. [60]PCBM) to take into consideration.
Intermediate Layers in Tandem Organic Solar Cells
Authors: Yuan Yongbo , Huang Jinsong , Li Gang
Published: March 2011

Tandem structures can boost the efficiency of organic solar cell to more than 15%, compared to the 10% limit of single layer bulk heterojunction devices. Design and fabricating of intermediate layers plays a very important role to achieve high device performance. This article will review the main experimental progresses of tandem organic solar cells, and focus on the intermediate layers (charge recombination layers) in both thermal evaporated and solution processed organic tandem solar cell devices.
The role of CREB signaling in Alzheimer’s disease and other cognitive disorders
Authors: Saura Carlos A. , Valero Jorge
Published: March 2011

Gene expression changes in the brain affect cognition during normal and pathological aging. Progress in understanding the cellular processes regulating gene expression networks in cognition is relevant to develop therapeutic interventions for age-related cognitive disorders. Synaptic efficacy mediating memory storage requires the activation of specific gene expression programs regulated, among others, by the transcription factor cAMP-response element binding protein (CREB). CREB signaling is essential for long-lasting changes in synaptic plasticity that mediates the conversion of short-term memory to long-term memory. CREB signaling has been recently involved in several brain pathological conditions including cognitive and neurodegenerative disorders. The β-amyloid (Aβ) peptide, which plays a crucial role in the pathogenesis of Alzheimer’s disease, alters hippocampal-dependent synaptic plasticity and memory and mediates synapse loss through the CREB signaling pathway. The fact that altered CREB signaling has been implicated in other cognitive disorders including Huntington’s disease and Rubinstein-Taybi and Coffin-Lowry syndromes suggests a crucial role of CREB signaling in cognitive dysfunction. In this review paper, we summarize recent findings indicating a role of CREB and its coactivators CREB binding protein and CREB-regulated transcription coactivator in cognition during normal and pathological aging. We also discuss the development of novel therapeutic strategies based on CREB targeting to ameliorate cognitive decline in aging and cognitive disorders.
Estradiol acts through nuclear- and membrane-initiated mechanisms to maintain a balance between GABAergic and glutamatergic signaling in the brain: implications for hormone replacement therapy
Authors: Moura Paula J. , Petersen Sandra L.
Published: March 2011

No abstract available
Peer-Assisted Learning Strategies in Human Anatomy & Physiology
Authors: Hughes Kathleen S.
Published: March 2011

Peer-assisted strategies foster learning in science courses. This article outlines a cross-year, peer-assisted learning program in a Human Anatomy and Physiology 1 course. The aim of this 2-year study was to implement the program and evaluate it on the basis of student performance and feedback. Former students were hired each year to lead optional discussion sessions. Student attendance was positively correlated with higher course averages and overall grade-point averages yet limited improvement in posttest scores. Students favorably evaluated the program and suggested improvements. Biology educators would benefit from a central interactive database devoted to peer-assisted learning in our discipline.
An Integrated Approach to Improve the Scientific Writing of Introductory Biology Students
Authors: Morgan William , Fraga Dean , Macauley William J.
Published: March 2011

We discuss a pedagogical strategy to improve the writing of laboratory reports. Our multipronged approach gauges students' comprehension beforehand, rewards early success, and focuses feedback on the most serious writing issues. In preliminary studies, more students were able to achieve our threshold for success in our introductory courses, and students reported being more motivated to write well.
A Simple, Inexpensive, Dynamic, & Hands-on Exercise for Prompting Discussion of the Characteristics of Living Things
Authors: Mickle James E. , Aune Patricia M.
Published: March 2011

Paper punch-out dots soaked in isopropyl alcohol will move about randomly when placed flat on the surface of water, superficially resembling swimming movements of single-celled protists. This exercise is a hands-on and dynamic activity to generate discussion on the generally accepted characteristics of living things.
Creative Ideas for Biology Podcasts: The Immune System as an Example
Authors: De Souza-Hart Janet
Published: March 2011

Podcasts (digital audio files) can be utilized creatively to supplement classroom learning. They can be both easily created by instructors and conveniently accessed by students. Students are very receptive to the use of this type of technology as a way to reinforce conceptual understanding of course material. An activity combining a podcast with an active-learning worksheet references the literary classic "The Lord of the Rings" as an analogy to help students understand the many proteins, cells, and processes involved in the human immune response. This activity has helped a significant number of students improve their understanding of this subject.
In vitro DNA-binding profile of transcription factors: methods and new insights
Authors: Wang Jinke , Lu Jie , Gu Guangming , Liu Yingxun
Published: March 2011

The DNA-binding specificity of transcription factors (TFs) has broad impacts on cell physiology, cell development and in evolution. However, the DNA-binding specificity of most known TFs still remains unknown. The specificity of a TF protein is determined by its relative affinity to all possible binding sites. In recent years, the development of several in vitro techniques permits high-throughput determination of relative binding affinity of a TF to all possible k bp-long DNA sequences, thus greatly promoting the characterization of DNA-binding specificity of many known TFs. All DNA sequences that can be bound by a TF with various binding affinities form their DNA-binding profile (DBP). The DBP is important to generate an accurate DNA-binding model, identify all DNA-binding sites and target genes of TFs in the whole genome, and build transcription regulatory network. This study reviewed these techniques, especially two master techniques: double-stranded DNA microarray and systematic evolution of ligands by exponential enrichment in combination with parallel DNA sequencing techniques (SELEX-seq).
A balancing act: mechanisms by which the fetus avoids rejection by the maternal immune system
Authors: Warning J C , McCracken S A , Morris J M
Published: March 2011

Successful pregnancy requires strict temporal regulation of maternal immune function to accommodate the growing fetus. Early implantation is facilitated by inflammatory processes that ensure adequate vascular remodeling and placental invasion. To prevent rejection of the fetus, this inflammation must be curtailed; reproductive immunologists are discovering that this process is orchestrated by the fetal unit and, in particular, the extravillous trophoblast. Soluble and particulate factors produced by the trophoblast regulate maternal immune cells within the decidua, as well as in the periphery. The aim of this review is to discuss the action of recently discovered immunomodulatory factors and mechanisms, and the potential effects of dysregulation of such mechanisms on the maternal immune response that may result in pregnancy loss or preeclampsia.
Functions of ectopically transplanted invasive horse trophoblast
Authors: de Mestre Amanda M , Hanlon David , Adams A Paige , Runcan Erin , Leadbeater Jane C , Erb Hollis N , Costa Christina C , Miller Donald , Allen W R , Antczak Douglas F
Published: March 2011

The invasive and fully antigenic trophoblast of the chorionic girdle portion of the equine fetal membranes has the capacity to survive and differentiate after transplantation to ectopic sites. The objectives of this study were to determine i) the survival time of ectopically transplanted allogeneic trophoblast cells in non-pregnant recipient mares, ii) whether equine chorionic gonadotropin (eCG) can be delivered systemically by transplanted chorionic girdle cells, and iii) whether eCG delivered by the transplanted cells is biologically active and can suppress behavioral signs associated with estrus. Ectopically transplanted chorionic girdle survived for up to 105 days with a mean lifespan of 75 days (95% confidence interval 55–94) and secreted sufficient eCG for the hormone to be measurable in the recipients’ circulation. Immunohistochemical labeling of serial biopsies of the transplant sites and measurement of eCG profiles demonstrated that graft survival was similar to the lifespan of equine endometrial cups in normal horse pregnancy. The eCG secreted by the transplanted cells induced corpora lutea formation and sustained systemic progesterone levels in the recipient mares, effects that are also observed during pregnancy. This in turn caused suppression of estrus behavior in the recipients for up to 3 months. Thus, ectopically transplanted equine trophoblast provides an unusual example of sustained viability and function of an immunogenic transplant in a recipient with an intact immune system. This model highlights the importance of innate immunoregulatory capabilities of invasive trophoblast cells and describes a new method to deliver sustained circulating concentrations of eCG in non-pregnant mares.