bluuebunny/crossref_metadata_2025 huggingface dataset:
Whole brain‐based analysis of regional white matter tract alterations in rare motor neuron diseases by diffusion tensor imaging
Authors: Unrath Alexander , Müller Hans‐Peter , Riecker Axel , Ludolph Albert C. , Sperfeld Anne‐Dorte , Kassubek Jan
Published: March 2010

Different motor neuron disorders (MNDs) are mainly defined by the clinical presentation based on the predominance of upper or lower motor neuron impairment and the course of the disease. Magnetic resonance imaging (MRI) mostly serves as a tool to exclude other pathologies, but novel approaches such as diffusion tensor imaging (DTI) have begun to add information on the underlying pathophysiological processes of these disorders in vivo. The present study was designed to investigate three different rare MNDs, i.e., primary lateral sclerosis (PLS, N = 25), hereditary spastic paraparesis (HSP, N = 24), and X‐linked spinobulbar muscular atrophy (X‐SBMA, N = 20), by use of whole‐brain‐based DTI analysis in comparison with matched controls. This analysis of white matter (WM) impairment revealed widespread and characteristic patterns of alterations within the motor system with a predominant deterioration of the corticospinal tract (CST) in HSP and PLS patients according to the clinical presentation and also in patients with X‐SBMA to a lesser degree, but also WM changes in projections to the limbic system and within distinct areas of the corpus callosum (CC), the latter both for HSP and PLS. In summary, DTI was able to define a characteristic WM pathoanatomy in motor and extra‐motor brain areas, such as the CC and the limbic projectional system, for different MNDs via whole brain‐based FA assessment and quantitative fiber tracking. Future advanced MRI‐based investigations might help to provide a fingerprint‐identification of MNDs. Hum Brain Mapp, 2010. © 2010 Wiley‐Liss, Inc.
Patterns of cortical degeneration in an elderly cohort with cerebral small vessel disease
Authors: Reid Andrew T. , van Norden Anouk G.W. , de Laat Karlijn F. , van Oudheusden Lucas J.B. , Zwiers Marcel P. , Evans Alan C. , de Leeuw Frank‐Erik , Kötter Rolf
Published: March 2010

Emerging noninvasive neuroimaging techniques allow for the morphometric analysis of patterns of gray and white matter degeneration in vivo, which may help explain and predict the occurrence of cognitive impairment and Alzheimer's disease. A single center prospective follow‐up study (Radboud University Nijmegen Diffusion tensor and Magnetic resonance imaging Cohort study (RUN DMC)) was performed involving 503 nondemented elderly individuals (50–85 years) with a history of symptomatic cerebral small vessel disease (SVD). Age was associated with a global reduction in cortical thickness, and this relationship was strongest for ventrolateral prefrontal cortex, auditory cortex, Wernicke's area, superior temporal lobe, and primary visual cortex. Right and left hemispheres differed in the thickness of language‐related areas. White matter (WM) lesions were generally negatively correlated with cortical thickness, primarily in individuals over the age of 60, with the notable exception of Brodmann areas 4 and 5, which were positively correlated in age groups 50–60 and 60–70, respectively. The observed pattern of age‐related decline may explain problems in memory and executive functions, which are already well documented in individuals with SVD. The additional gray matter loss affecting visual and auditory cortex, and specifically the head region of primary motor cortex, may indicate morphological correlates of impaired sensory and motor functions. The paradoxical positive relationship between WM lesion volume and cortical thickness in some areas may reflect early compensatory hypertrophy. This study raises a further interest in the mechanisms underlying cerebral gray and white matter degeneration in association with SVD, which will require further investigation with diffusion weighted and longitudinal MR studies. Hum Brain Mapp, 2010. © 2010 Wiley‐Liss, Inc.
When response inhibition is followed by response reengagement: An event‐related fMRI study
Authors: Boecker Maren , Drueke Barbara , Vorhold Verena , Knops Andre , Philippen Bernd , Gauggel Siegfried
Published: March 2010

In the course of daily living, changing environmental demands often make our actions, once initiated, unnecessary or even inappropriate. Under such circumstances, the ability to inhibit the obsolete action and to update behavior can be of vital importance. Previous lesion and neuroimaging studies have shown that the right prefrontal cortex and the basal ganglia seem to play an important role in the inhibition of already initiated motor responses. The present study was designed to investigate whether the neural activity of inhibitory motor control was altered if the inhibition process was succeeded by an additional process, namely the reengagement into an alternative action. Therefore, cerebral blood oxygenation during performance of a stop‐change paradigm was registered in 15 male participants using event‐related functional magnetic resonance imaging. Data analysis showed, that during successful and failed stopping and changing (response inhibition and subsequent response reengagement) of initiated motor responses a very similar network was activated including primarily the right inferior frontal cortex (IFC). Besides, stopping‐related activation in right IFC was significantly greater for fast inhibitors than for slow ones. Results of the present study thus further underline the important role of right IFC in response inhibition and suggest that the inhibition process functions similarly regardless whether changing task demands require the complete suppression of an already initiated motor response or its suppression and a subsequent response reengagement into an alternative action. Hum Brain Mapp, 2010. © 2010 Wiley‐Liss, Inc.
Organizational commitment for knowledge workers: The roles of perceived organizational learning culture, leader–member exchange quality, and turnover intention
Authors: Joo Baek‐Kyoo (Brian)
Published: March 2010

This article investigates the impact of perceived organizational learning culture and leader–member exchange (LMX) quality on organizational commitment and eventually on employee turnover intention. Employees exhibited the highest organizational commitment when they perceived a higher learning culture and when they were supervised in a supportive fashion. Employee turnover intention was fully mediated by organizational commitment. Overall, 43% of the variance in organizational commitment was explained by organizational learning culture and LMX quality. About 40% of the variance in turnover intention was explained by organizational commitment. Thus, perceived organizational learning culture and LMX quality (antecedents) impacted on organizational commitment, which in turn contributed negatively to employee turnover intention (consequence).
The development and resulting performance impact of positive psychological capital
Authors: Luthans Fred , Avey James B. , Avolio Bruce J. , Peterson Suzanne J.
Published: March 2010

Recently, theory and research have supported psychological capital (PsyCap) as an emerging core construct linked to positive outcomes at the individual and organizational level. However, to date, little attention has been given to PsyCap development through training interventions; nor have there been attempts to determine empirically if such PsyCap development has a causal impact on participants' performance. To fill these gaps we first conducted a pilot test of the PsyCap intervention (PCI) model with a randomized control group design. Next, we conducted a follow‐up study with a cross section of practicing managers to determine if following the training guidelines of the PCI caused the participants' performance to improve. Results provide beginning empirical evidence that short training interventions such as PCI not only may be used to develop participants' psychological capital, but can also lead to an improvement in their on‐the‐job performance. The implications these findings have for human resource development and performance management conclude the article.
Can the distribution of headwater stream chemistry be predicted from downstream observations?
Authors: Temnerud J. , Fölster J. , Buffam I. , Laudon H. , Erlandsson M. , Bishop K.
Published: March 2010

Small streams with catchment areas < 2 km2 make up the majority of all stream length and are of great ecological importance. Surveys of first and second order streams reveal great spatial and temporal variability in the water chemistry of these headwaters, but their assessment presents a serious challenge since systematic, representative data are usually only collected in larger streams and rivers. Using low flow synoptic survey data from seven mesoscale Swedish catchments, this study tests the hypothesis that downstream monitoring data can be used to predict key features of the distribution of chemistry in headwater streams [median and interquartile range (IQR)]. Three ecologically relevant analytes were tested: pH, acid neutralizing capacity (ANC) and total organic carbon (TOC). For all seven catchments, the outlets (36–127 km2) were considerably less acid with lower TOC than the median of the headwaters (<2 km2, N = 19–45). Among catchments, headwater median and IQR were positively correlated with the value at the outlet, for all three analytes. A univariate general linear model (GLM) was used to predict the headwater chemistry distribution for each catchment from its outlet chemistry, using the relationship established with the other six catchments. Headwater median pH and IQR of ANC were well predicted by a single downstream sample [median adj. R2 ∼ 0·7, normalized root mean squared error (NRMSE) < 0·7]. Other response variables were not as well predicted, with median adj. R2 ranging from 0·08 to 0·48, and NRMSE up to 1·1. A minority of models were significant at α = 0·05, in part due to the limited availability of catchments with such extensive survey data. However, the clear trends observed suggest that with additional model development, downstream chemistry could ultimately provide a valuable tool for characterizing the range of chemistry in the contributing headwaters. Copyright © 2010 John Wiley & Sons, Ltd.
The controls on boreal peatland surface water chemistry in Northern Alberta, Canada
Authors: Whitfield Colin J. , Aherne Julian , Gibson John J. , Seabert Tim A. , Watmough Shaun A.
Published: March 2010

Spatial and temporal variability in surface water chemistry, organic soil chemistry and hydrologic indicators were investigated at three poor‐fen complexes in two boreal catchments in Northern Alberta to provide insight into the dominant controls on surface water chemistry. Improved understanding of these controls is required to enable prediction of runoff chemistry in the region under changing atmospheric deposition conditions. Surface water chemistry exhibited considerable variability; within each fen conductivity, dissolved organic carbon (DOC), and Cl− tended to decrease and pH tended to increase with increasing distance from the lake edge. Variations in evaporative isotopic enrichment in 2H and 18O, expressed as deuterium excess, were used to distinguish between throughflow waters and those that were more evaporatively enriched. Throughflow surface waters were more acidic primarily due to higher concentrations of DOC and NO3−. Exchangeable base saturation and pH of organic soils were strongly related to surface water chemistry at two of the fen complexes, demonstrating the capacity for cation exchange to influence surface water chemistry. Fen surface water concentrations of most elements and DOC increased during the summer period (between June and August), while pH of water decreased. Evaporative concentration of the surface waters was a dominant driver, with surface water temperature increasing at both catchments. Localized groundwater discharge was an important contributor of base cations to the fens, while the organic soils are sinks for atmospherically deposited SO42−, N and Cl−. Copyright © 2010 John Wiley & Sons, Ltd.
How do the rain rates of sub‐event intervals such as the maximum 5‐ and 15‐min rates (I5orI30) relate to the properties of the enclosing rainfall event?
Authors: Dunkerley David L.
Published: March 2010

The intensity‐duration properties of rain have been explored using various approaches, including daily or hourly data, IDF and event‐based analyses, and the study of rain properties across intra‐event durations such as the widely usedI30indicator of peak event rain rate. This article explores the way in which intra‐event rain rates (IERRs) such asI30vary with the duration of the enclosing event and with the approach used to delineate events. Pluviograph records from two Australian sites are subdivided into events using the minimum inter‐event time (MIT) approach, and the duration, depth and rain rate properties of the events determined. The IERRs for intervals from 1 to 60 min are extracted for each event, and generally these rates (includingI30) exhibit statistically significant increases in longer enclosing rain events. The mean value of parameters such asI5andI30across all rain events also varied in more complex ways with the MIT criterion used to define the enclosing events. Thus, measures of IERR are significantly affected by the data processing protocols used to derive them. Wider exploration of these phenomena from other rainfall climates will assist in the interpretation of hydrologic, soil erosion, agrochemical wash‐off and other data that in published literature are interpreted differently in relation to event mean rainfall properties or to selected intra‐event properties such asI30. Understanding of these issues is important in the selection of an appropriate rainfall descriptor in event‐based hydrologic and erosional research. Copyright © 2010 John Wiley & Sons, Ltd.
Topographic controls on shallow groundwater dynamics: implications of hydrologic connectivity between hillslopes and riparian zones in a till mantled catchment
Authors: Detty J. M. , McGuire K. J.
Published: March 2010

Hydrologic connectivity is regarded as one of the key controls in determining catchment rainfall–run‐off response and has been linked to the export of solutes from uplands to streams. We sought to identify the patterns of hydrologic connectivity within a small forested watershed by monitoring the shallow groundwater fluctuations of simple topographically defined landform sequences (footslope–backslope–shoulder). A spatially distributed instrument network was employed to continuously measure hydrometric responses of the shallow subsurface during seasonal wet‐up from summer through winter in a small till mantled research catchment. We demonstrate that the spatial patterns of shallow water table extent and duration, and therefore hydrologic connectivity, had a strong seasonal signature. During the low antecedent soil moisture conditions typically associated with the growing season, water tables were patchy, discontinuous, and only the wettest near‐stream footslope areas were consistently hydrologically connected with the stream network. During the dormant season, footslopes and backslopes maintained water tables that persisted between storm events and were almost continuously connected with the stream network. In the largest storm events, the typically driest landforms (shoulder slopes) established shallow transient water tables, suggesting that nearly the entire catchment was temporarily hydrologically connected with the stream network. In addition, we found significant differences (p < 0·05) in the magnitude and duration of groundwater responses to rainfall among landform groups both seasonally and during events. These results have implications for using a similarity approach in representing characteristic hydrologic responses of topographically defined watershed elements, determining hydrologic connectivity between watershed elements, as well as for understanding solute transport in catchments. Copyright © 2010 John Wiley & Sons, Ltd.
Polymer LEDs as a physics tool
Authors: Tessler Nir , Cleave Vicki , Pinner Dickon J.
Published: March 2010

We present a systematic experimental and theoretical study of physical mechanisms governing the operation of polymer light‐emitting diodes. We show that through self‐consistent modeling we can address both charge transport and exciton generation. Electron and hole mobility in several polymers has been characterized experimentally. Characterization of excitons and especially of triplet‐excitons is achieved through use of a triplet‐emitting molecule.
Overcoming obstacles to campus assessment
Authors: Volkwein J. Fredericks
Published: March 2010

The chapter offers four practical suggestions for implementing campus assessment programs based on an accreditation self‐study at a research university.
Polymorphonuclear leukocyte inhibition of monocytes/macrophages in the foreign body reaction
Authors: Kirk James T. , McNally Amy K. , Anderson James M.
Published: March 2010

The effect of polymorphonuclear leukocytes (PMNs) on the subsequent chronic phase macrophage‐mediated foreign body reaction has not been previously investigated. Furthermore, while monocyte/macrophage‐produced cytokines such as GM‐CSF, G‐CSF, or IL‐1β have been shown to increase PMN survival in vitro, few studies have examined the impact of directly cocultured monocytes/macrophages on PMN viability. To this end, we used our established in vitro system of interleukin (IL)‐4‐induced monocyte‐derived macrophage fusion to examine the role of PMNs in the subsequent foreign body reaction. Monocytes were directly cultured with PMNs for 3 days before the addition of IL‐4 to induce monocyte‐derived macrophage fusion to facilitate foreign body giant cell (FBGC) formation by days 7 and 10 of culture. Optical microscopy was used to quantitatively determine adherent monocyte density, percent macrophage fusion, and FBGC density. A colorimetric MTT assay was used to assess PMN viability for direct cocultures of monocytes/macrophages and PMNs. Our results strongly suggest that the presence of PMNs inhibit IL‐4‐induced macrophage fusion and FBGC formation. Additionally, our findings demonstrate that cocultures containing PMNs and monocytes/macrophages increases PMN survival with respect to PMN‐only cultures in vitro. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2010
Low molecular weight hyaluronic acid effects on murine macrophage nitric oxide production
Authors: Lyle Daniel B. , Breger Joyce C. , Baeva Larissa F. , Shallcross Jonathan C. , Durfor Charles N. , Wang Nam Sun , Langone John J.
Published: March 2010

Hyaluronic acid (HA) is increasingly used for a number of medical device applications. Since the chemical structure of HA is identical no matter its bacterial or animal origin, it should be the ideal biomaterial. However, short term transient inflammatory reactions are common, while rare long‐term adverse events may correlate with subclinical chronic inflammation. Concern has been raised that low molecular weight components or degradation fragments from implanted HA may directly stimulate inflammatory reactions. This study examined a panel of HA molecular weights from the unitary disaccharide up to 1.7 × 106 Dalton lengths, in which endotoxin was assayed at a very low level (less than 0.03 EU/mg). The murine cell line RAW 264.7, rat splenocytes, and rat adherent differentiated primary macrophages were assayed for nitric oxide production under a variety of inflammatory conditions plus or minus HA. Under the highest inflammatory states, nitric oxide production was mildly suppressed by HMW‐HA while slightly augmented by LMW‐HA at mg/mL concentrations. However, at micromolar concentrations fragments below 5000 Daltons, thought to have drug‐like qualities, were without effect. These data support the hypothesis that if endotoxin is reduced to an extremely low level, LMW‐HA may not directly provoke normal tissue macrophage‐mediated inflammatory reactions. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2010
Effect of bone graft substitute on marrow stromal cell proliferation and differentiation
Authors: Siggers Kevin , Frei Hanspeter , Fernlund Göran , Rossi Fabio
Published: March 2010

Marrow stromal cells (MSCs) are ideally suited for tissue engineered bone grafts since they have the potential to regenerate bone, but may also maintain the homeostasis of the repaired tissue through their ability for self‐renewal. An ideal bone graft substitute should support MSC self‐renewal as well as differentiation to ensure complete bone defect regeneration and maintenance. The purpose of this investigation was to determine the effect of different substrate materials on MSC expansion and differentiation. Calcium polyphosphate (CPP), bone and hydroxyapatite/tricalcium phosphate (HA/TCP) were seeded with rat MSCs and maintained in culture conditions that promote cell expansion. At 0, 3, 7, 14, and 21 days cell numbers were determined by measuring their metabolic activity using a MTT assay and the frequency of cycling cells by 24 hr BrdU incorporation. Osteogenic, chondrogenic, and adipogenic marker expression in these cultures was measured by qRT‐PCR. An initial drop in cell numbers was observed on all substrates. CPP and bone, but not HA/TCP supported an increase in proliferating cells at day 14 and 21. In addition, no upregulation of mature bone markers was observed in cells cultured on CPP and bone, which suggests that these substrates support the expansion of undifferentiated MSCs. In contrast, cell numbers on HA/TCP decreased with time and only rare BrdU positive cells were observed. This decrease in proliferation correlated with the down regulation of osteogenic progenitor markers and the substantial increase in mature osteocyte markers, indicating that HA/TCP favors MSC differentiation and maturation along the osteogenic lineage. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2010
Articular cartilage tissue engineering based on a mechano‐active scaffold made of poly(L‐lactide‐co‐ε‐caprolactone): In vivo performance in adult rabbits
Authors: Xie Jun , Han Zhiyi , Naito Masatoshi , Maeyama Akira , Kim Soo Hyun , Kim Young Ha , Matsuda Takehisa
Published: March 2010

Our previous studies showed that a mechano‐active scaffold made of poly(L‐lactide‐co‐ε‐caprolactone) (PLCL) exhibited a high potential to realize the formation of a functional, engineered cartilage in vitro. This animal study therefore was designed to investigate the feasibility of repairing on osteochondral defect with the use of bone marrow‐derived mesenchymal stem cells (BMSCs) incorporated with a PLCL scaffold. Rabbit BMSCs, isolated and subsequently cultured in monolayer, were seeded into a porous PLCL scaffold sponge following an implantation onto a full‐thickness osteochondral defect (diameter of 4.5 mm, depth of 5 mm) that was artificially created on the medial femoral condyles at a high load‐bearing site on a rabbit's knee joint. Time‐dependent healing of the defect was evaluated by macroscopic, histological examinations at both 3‐ and 6‐month‐implantations, respectively. A PLCL sponge incorporated with BMSCs exhibited sufficient structural support, resulting in new osteochondral tissue regeneration: a physiologically well‐integrated subchondral bone formation, a hyaline cartilage‐like morphology containing chondrocytes surrounded by abundant cartilaginous matrices. In addition, quantitative biochemical assays also demonstrated high potential for the synthesis of sulfated glycosaminoglycan and collagen, both of which are biomolecules essential to extracelluar matrix in normal cartilage tissue. In contrast, defects filled with cell‐free PLCL scaffold or left empty showed a very limited potential for regeneration. Our findings suggest that a composite of PLCL‐based sponge scaffold and BMSCs promote the repair of osteochondral defects at high load‐bearing sites in adult rabbits. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2010
High-phosphate-induced calcification is related to SM22α promoter methylation in vascular smooth muscle cells
Authors: de Oca Addy Montes , Madueño Juan A , Martinez-Moreno Julio M , Guerrero Fatima , Muñoz-Castañeda Juan , Rodriguez-Ortiz Marien E , Mendoza Francisco J , Almaden Yolanda , Lopez Ignacio , Rodriguez Mariano , Aguilera-Tejero Escolastico
Published: March 2010

Hyperphosphatemia is closely related to vascular calcification in patients with chronic kidney disease. Vascular smooth muscle cells (VSMCs) exposed to high phosphate concentrations in vitro undergo phenotypic transition to osteoblast-like cells. Mechanisms underlying this transdifferentiation are not clear. In this study we used two in vitro models, human aortic smooth muscle cells and rat aortic rings, to investigate the phenotypic transition of VSMCs induced by high phosphate. We found that high phosphate concentration (3.3 mmol/L) in the medium was associated with increased DNA methyltransferase activity and methylation of the promoter region of SM22α. This was accompanied by loss of the smooth muscle cell–specific protein SM22α, gain of the osteoblast transcription factor Cbfa1, and increased alkaline phosphatase activity with the subsequent in vitro calcification. The addition of a demethylating agent (procaine) to the high-phosphate medium reduced DNA methyltransferase activity and prevented methylation of the SM22α promoter, which was accompanied by an increase in SM22α expression and less calcification. Additionally, downregulation of SM22α, either by siRNA or by a methyl group donor (S-adenosyl methionine), resulted in overexpression of Cbfa1. In conclusion, we demonstrate that methylation of SM22α promoter is an important event in vascular smooth muscle cell calcification and that high phosphate induces this epigenetic modification. These findings uncover a new insight into mechanisms by which high phosphate concentration promotes vascular calcification. © 2010 American Society for Bone and Mineral Research
Mechanism underlying long‐term regulation of 3‐hydroxy‐3‐methylglutaryl coenzyme A reductase during L6 myoblast differentiation
Authors: Trapani Laura , Martini Chiara , Trentalance Anna , Pallottini Valentina
Published: March 2010

3‐Hydroxy 3‐methylglutaryl Coenzyme A reductase (HMG‐CoAR) and its end‐products are crucial for insulin‐induced differentiation of fetal rat myoblasts (L6) both at early and terminal stages of development. Inhibition of HMG‐CoAR activity and reduction of the enzyme levels impair the expression of L6 differentiation markers and prevent myoblast fusion into multinucleated syncytia. The mechanism underlying the modulation of this crucial enzyme so that muscular differentiation can occur is poorly understood. Thus, the aim of this work was to explore the long‐term regulation of HMG‐CoAR in an attempt to provide a new molecular basis for the control of muscle development. All experiments were performed in L6 rat myoblasts induced to differentiate utilizing insulin. The results indicate the following: (i) at early stages of L6 differentiation, the increase in HMG‐CoAR protein levels is probably due to transcriptional induction and a decrease in the enzyme degradation rate; (ii) the subsequent reduction of HMG‐CoAR protein levels is related both to an increased degradation rate and reduced gene transcription, as indicated by the rise of Insig‐1 levels and the subsequent decrease in the amount of n‐SREBP‐1; (iii) in the terminal stages of myogenesis, reduced protein levels of HMG‐CoAR could be ascribed to the decrease in gene transcription while its degradation rate is not affected. By highlighting the mechanisms involved in HMG‐CoAR long‐term regulation during myogenesis, this work provides useful information for searching for tools to improve the regenerative ability of muscle tissue and for the development of new pharmacological treatments of myopathies. J. Cell. Biochem. 110: 392–398, 2010. © 2010 Wiley‐Liss, Inc.
TRAIL/TRAIL‐R in hematologic malignancies
Authors: Testa Ugo
Published: March 2010

Defects in apoptosis are observed in many cancer cell types and contribute in a relevant way to tumorigenesis. Apoptosis is a complex and well‐regulated cell death program that plays a key role in the control of cell homeostasis, particularly at the level of the hematopoietic system. Apoptosis can be initiated through two different mechanisms involving either activation of the death receptors (extrinsic pathway) or activation of a mitochondrial apoptotic process (intrinsic pathway). Among the various death receptors a peculiar role is played by TNF‐related apoptosis‐inducing ligand (TRAIL)‐receptors (TRAIL‐Rs) and their ligand TRAIL. TRAIL recently received considerable interest for its potent anti‐tumor killing activity, sparing normal cells. Here, we will review the expression and the abnormalities of TRAIL/TRAIL‐R system in hematologic malignancies. The large majority of primary hematologic tumors are resistant to TRAIL‐mediated apoptosis, basically due to the activation of anti‐apoptotic signaling pathway (such as NF‐κB), overexpression of anti‐apoptotic proteins (such as FLIP, Bcl‐2, XIAP) or expression of TRAIL decoy receptors or reduced TRAIL‐R1/‐R2 expression. Strategies have been developed to bypass this TRAIL resistance and are based on the combination of TRAIL with chemotherapy or radiotherapy, or with proteasome or histone deacetylase or NF‐κB inhibitors. The agents used in combination with TRAIL either enhance TRAIL‐R1/‐R2 expression or decrease expression of anti‐apoptotic proteins (c‐FLIP, XIAP, Bcl‐2). Many of these combinatorial therapies hold promise for future developments in treatment of hematologic malignancies. J. Cell. Biochem. 110: 21–34, 2010. © 2010 Wiley‐Liss, Inc.
Piscirickettsia salmonis induces apoptosis in macrophages and monocyte‐like cells from rainbow trout
Authors: Rojas Verónica , Galanti Norbel , Bols Niels C. , Jiménez Verónica , Paredes Rodolfo , Marshall Sergio H.
Published: March 2010

Piscirickettsia salmonis is the etiologic agent of the salmonid rickettsial septicemia (SRS) which causes significant losses in salmon production in Chile and other and in other regions in the southern hemisphere. As the killing of phagocytes is an important pathogenic mechanism for other bacteria to establish infections in vertebrates, we investigated whether P. salmonis kills trout macrophages by apoptosis. Apoptosis in infected macrophages was demonstrated by techniques based on morphological changes and host cell DNA fragmentation. Transmission electron microcopy showed classic apoptotic characteristics and terminal deoxynucleotidyl transferase‐mediated dUTP nick end labeling showed fragmented DNA. Programmed cell death type I was further confirmed by increased binding of annexin V to externalized phosphatidylserine in infected macrophages. Moreover, significant increases of caspase 3 activation were detected in infected cells and treatment with caspase inhibitor caused a decrease in levels of apoptosis. This is the first evidence that P. salmonis induces cell death in trout macrophages. This could lead to bacterial survival and evasion of the host immune response and play an important role in the establishment of infection in the host. J. Cell. Biochem. 110: 468–476, 2010. © 2010 Wiley‐Liss, Inc.
Pentapeptide insertion mutagenesis of the Hoxa1 protein: Mapping of transcription activation and DNA‐binding regulatory domains
Authors: Lambert Barbara , Vandeputte Julie , Desmet Pierre‐Marie , Hallet Bernard , Remacle Sophie , Rezsohazy René
Published: March 2010

The mode of action of Hoxa1, like that of most Hox proteins, remains poorly characterized. In an effort to identify functional determinants contributing to the activity of Hoxa1 as a transcription factor, we generated 18 pentapeptide insertion mutants of the Hoxa1 protein and we assayed them in transfected cells for their activity on target enhancers from the EphA2 and Hoxb1 genes known to respond to Hoxa1 in the developing hindbrain. Only four mutants displayed a complete loss‐of‐function. Three of them contained an insertion in the homeodomain of Hoxa1, whereas the fourth loss‐of‐function mutant harbored an insertion in the very N‐terminal end of the protein. Transcription activation assays in yeast further revealed that the integrity of both the N‐terminal end and homeodomain is required for Hoxa1‐mediated transcriptional activation. Furthermore, an insertion in the serine–threonine–proline rich C‐terminal extremity of Hoxa1 induced an increase in activity in mammalian cells as well as in the yeast assay. The C‐terminal extremity thus modulates the transcriptional activation capacity of the protein. Finally, electrophoretic mobility shift assays revealed that the N‐terminal extremity of the protein also exerts a modulatory influence on DNA binding by Hoxa1–Pbx1a heterodimers. J. Cell. Biochem. 110: 484–496, 2010. © 2010 Wiley‐Liss, Inc.
Calcium oscillations induced by gambierol in cerebellar granule cells
Authors: Alonso E. , Vale C. , Sasaki M. , Fuwa H. , Konno Y. , Perez S. , Vieytes M.R. , Botana L.M.
Published: March 2010

Gambierol is a marine polyether ladder toxin derived from the dinoflagellate Gambierdiscus toxicus. To date, gambierol has been reported to act either as a partial agonist or as an antagonist of sodium channels or as a blocker of voltage‐dependent potassium channels. In this work, we examined the cellular effect of gambierol on cytosolic calcium concentration, membrane potential and sodium and potassium membrane currents in primary cultures of cerebellar granule cells. We found that at concentrations ranging from 0.1 to 30 µM, gambierol‐evoked [Ca2+]c oscillations that were dependent on the presence of extracellular calcium, irreversible and highly synchronous. Gambierol‐evoked [Ca2+]c oscillations were completely eliminated by the NMDA receptor antagonist APV and by riluzole and delayed by CNQX. In addition, the K+ channel blocker 4‐aminopyridine (4‐AP)‐evoked cytosolic calcium oscillations in this neuronal system that were blocked by APV and delayed in the presence of CNQX. Electrophysiological recordings indicated that gambierol caused membrane potential oscillations, decreased inward sodium current amplitude and decreased also outward IA and IK current amplitude. The results presented here point to a common mechanism of action for gambierol and 4‐AP and indicate that gambierol‐induced oscillations in cerebellar neurons are most likely secondary to a blocking action of the toxin on voltage‐dependent potassium channels and hyperpolarization of sodium current activation. J. Cell. Biochem. 110: 497–508, 2010. © 2010 Wiley‐Liss, Inc.
Investigation of binding features: Effects on the interaction between CYP2A6 and inhibitors
Authors: Ai Chunzhi , Li Yan , Wang Yonghua , Li Wei , Dong Peipei , Ge Guangbo , Yang Ling
Published: March 2010

A computational investigation has been carried out on CYP2A6 and its naphthalene inhibitors to explore the crucial molecular features contributing to binding specificity. The molecular bioactive orientations were obtained by docking (FlexX) these compounds into the active site of the enzyme. And the density functional theory method was further used to optimize the molecular structures with the subsequent analysis of molecular lipophilic potential (MLP) and molecular electrostatic potential (MEP). The minimal MLPs, minimal MEPs, and the band gap energies (the energy difference between the highest occupied molecular orbital and lowest unoccupied molecular orbital) showed high correlations with the inhibition activities (pIC50s), illustrating their significant roles in driving the inhibitor to adopt an appropriate bioactive conformation oriented in the active site of CYP2A6 enzyme. The differences in MLPs, MEPs, and the orbital energies have been identified as key features in determining the binding specificity of this series of compounds to CYP2A6 and the consequent inhibitory effects. In addition, the combinational use of the docking, MLP and MEP analysis is also demonstrated as a good attempt to gain an insight into the interaction between CYP2A6 and its inhibitors. © 2010 Wiley Periodicals, Inc. J Comput Chem, 2010
A computational study on the capability of borane‐cyclic boryl anion adducts to act as hydrogen atom donors
Authors: Lai Chin‐Hung , Chou Pi‐Tai
Published: March 2010

According to our theoretical approaches, a cyclic boryl anion can act as a Lewis base like its isoelectronic counterpart N‐heterocyclic carbene, reducing the homolytic bond dissociation energy of BH in BH3. However, the donating efficiency is affected by the counter cation in both gas phase and nonpolar solvents. Moreover, we also predict the seven‐membered ring boryl anion 5, although it has not yet synthesized, to be the most efficient reagent to reduce the bond dissociation energy of a BH bond in BH3. This study may thus pave another avenue toward Lewis base induced hydrogen atom abstraction in BH3. © 2010 Wiley Periodicals, Inc. J Comput Chem, 2010
Alpha sphere filter method: Application of pseudomolecular descriptors in virtual screening of 2D chemical structures
Authors: Muta Hajime , Hirayama Noriaki
Published: March 2010

Alpha sphere filter (ASF) method is a novel previrtual screening method to undertake a rapid virtual screening of a huge chemical space. The small‐molecule binding site of a target molecule can be characterized by a set of alpha spheres generated at the site. Two types of pseudomolecules representing molecules that likely fit into the binding site were molded from the set of alpha spheres. Based on the pseudomolecules, pseudomolecular descriptors corresponding to the conventional two‐dimensional (2D) molecular descriptors were calculated. The correlations between the pseudomolecular descriptors and the 2D molecular descriptors were analyzed for a set of high‐quality X‐ray structures of the complexes between ligands and proteins. By use of these correlations, specific value ranges of the 2D molecular descriptors were determined. These value ranges were applied in virtual screening. In a trial to screen 200 active ligands out of a chemical database with 42,547 molecules, the enrichment rate of 5.8 was attained. The enrichment rate was good enough for a prescreening tool prior to docking simulations. As the ASF method screens molecules by 2D molecular descriptors, it is rapid enough to screen a huge chemical space and could significantly decrease the number of trivial compounds to be considered in the following docking simulations. Therefore, the ASF method can contribute to enlarge the possibility of virtual screening. © 2010 Wiley Periodicals, Inc. J Comput Chem, 2010
A toolkit to assist ONIOM calculations
Authors: Tao Peng , Schlegel H. Bernhard
Published: March 2010

A general procedure for quantum mechanics and molecular mechanics (QM/MM) studies on biochemical systems is outlined, and a collection of PERL scripts to facilitate ONIOM‐type QM/MM calculations is described. This toolkit is designed to assist in the different stages of an ONIOM QM/MM study of biomolecules, including input file preparation and checking, job monitoring, production calculations, and results analysis. An iterative procedure for refitting the partial charges of QM region atoms is described and yields a more accurate treatment of the electrostatic interaction between QM and MM regions during QM/MM calculations. The toolkit fully supports this partial charge‐refitting procedure. By using this toolkit for file conversions, structure manipulation, input sanity checks, parameter lookup, charge refitting, tracking optimizations, and analyzing results, QM/MM studies of large size biochemical systems can be much more convenient and practical. © 2010 Wiley Periodicals, Inc. J Comput Chem, 2010
Parental relationships among three grape varieties studied by MALDI of grape seed protein profiles
Authors: Bertazzo Antonella , Rosso Mirko De , Vedova Antonio Dalla , Agnolin Fabio , Flamini Riccardo , Traldi Pietro
Published: March 2010

Two Raboso cultivars, i.e. Raboso Veronese and Raboso Piave, are two black Vitis vinifera varieties. A genetic study suggested that Raboso Veronese is the progeny of a spontaneous cross between Raboso Piave and Marzemina Bianca cultivars. Parental relationships are usually investigated by genetic studies, which are effective to establish genetic links among different cultivars. Considering that proteome is the genome expression, in this article we evaluated the power of seed protein profiles obtained by matrix‐assisted laser desorption/ionization (MALDI)/MS for parentage investigation. The three cultivars lead to very similar spectra with differences in the relative intensity of the most abundant species and the presence of very weak specific ions. In order to evaluate the analytical significance of these aspects, the variability due to instrumental factors and due to different harvesting areas and years of the same cultivars have been considered and measured by the calculation of discrepancy factor values. On one hand, the results obtained can be considered a valid confirmation of the genomic findings, whereas on the other hand, the results provide evidence for the ability of MALDI/MS to individuate minor differences in protein profiles of complex protein mixtures. Copyright © 2010 John Wiley & Sons, Ltd.
Hepatitis C virus core protein compromises iron‐induced activation of antioxidants in mice and HepG2 cells
Authors: Moriya Kyoji , Miyoshi Hideyuki , Shinzawa Seiko , Tsutsumi Takeya , Fujie Hajime , Goto Koji , Shintani Yoshizumi , Yotsuyanagi Hiroshi , Koike Kazuhiko
Published: March 2010

One of the characteristics of hepatitis C virus (HCV) infection is the unusual augmentation of oxidative stress, which is exacerbated by iron accumulation in the liver, as observed frequently in hepatitis C patients. Using a transgenic mouse model, the core protein of HCV was shown previously to induce the overproduction of reactive oxygen species (ROS) in the liver. In the present study, the impact of iron overloading on the oxidant/antioxidant system was examined using this mouse model and cultured cells. Iron overloading caused the induction of ROS as well as antioxidants. However, the augmentation of some antioxidants, including heme oxygenase‐1 and NADH dehydrogenase, quinone 1, was compromised by the presence of the core protein. The attenuation of iron‐induced augmentation of heme oxygenase‐1 was also confirmed in HepG2 cells expressing the core protein. This attenuation was not dependent on the Nrf2 transcription factor. Thus, HCV infection not only induces oxidative stress but also hampers the iron‐induced antioxidant activation in the liver, thereby exacerbating oxidative stress that would facilitate hepatocarcinogenesis. J. Med. Virol. 82: 776–782, 2010. © 2010 Wiley‐Liss, Inc.
Development and implementation of influenza a virus subtyping and detection of genotypic resistance to neuraminidase inhibitors
Authors: Ruiz‐Carrascoso Guillermo , Casas Inmaculada , Pozo Francisco , Pérez‐González Carmen , Reina Jordi , Pérez‐Breña Pilar
Published: March 2010

Influenza virus hemagglutinin and neuraminidase, surface glycoproteins with an essential role in viral pathogenesis, are important antigen determinants and essential markers for epidemiological surveillance. Neuraminidase is also a suitable target for designing antiviral drugs. The introduction into clinical practice of neuraminidase inhibitors and the development of random point mutations have increased the emergence of drug‐resistant viruses. A universal RT nested PCR‐based system has been developed for subtyping H1, H3, N1 and N2, in influenza A viruses of human or animal origin. The subsequent sequencing and analysis of the hemagglutinin and neuraminidase templates reveal antigenic and receptor binding changes in the HA1 subunit and mutations of clinical relevance concerning resistance to neuraminidase inhibitors. The specificity and sensitivity of the method were evaluated using 113 influenza A isolates, 105 influenza A positive respiratory samples obtained from patients and 29 prototype strains of both human and animal origin. The resulting analytical sensitivity of the subtyping techniques is one to at least 100 molecules of cloned DNA product in a final reaction volume of 50 µl. In the course of implementing the method, two H1N1 isolates with the H274Y mutation in the neuraminidase segment have been detected and their molecular features analyzed. The emergence of influenza virus resistance makes the neuraminidase genetic characterization and surveillance activities to detect antiviral resistance necessary. J. Med. Virol. 82: 843–853, 2010. © 2010 Wiley‐Liss, Inc.
New variations of Epstein–Barr virus‐encoded small RNA genes in nasopharyngeal carcinomas, gastric carcinomas, and healthy donors in northern China
Authors: Wang Yun , Zhang Xia , Chao Yan , Jia Yuping , Xing Xiaoming , Luo Bing
Published: March 2010

It has been generally believed that the Epstein–Barr virus (EBV)‐encoded small RNA 1 and 2 (EBER1 and EBER2) genes are conserved as two families that correlated with type 1 (B95‐8) and type 2 (AG876 or P3HR‐1) EBV strains. EBER polymorphism and its association with EBV‐associated disease have not received much attention. To explore the variations of EBER genes in different malignancies and healthy donors, the sequences of EBER genes were analyzed in 154 EBV‐positive samples, including 47 nasopharyngeal carcinoma (NPC), 50 EBV‐associated gastric carcinoma (EBVaGC) biopsies and 57 throat washing (TW) samples from healthy donors in northern China, where NPC is non‐endemic. Three main distinct variants of EBER genes, designated as EB‐6m, EB‐8m, and EB‐10m, were identified. EB‐6m had a previously identified EBER sequence identical to P3HR‐1 and was found in 33/47 (70.2%) NPC, 48/50 (96.0%) EBVaGC, and 54/57 (94.7%) TW isolates. EB‐8m and EB‐10m were new EBER variants with more mutations in EBER2 genes. They were found in 13/47 (27.7%) NPC cases, whereas in only 1/50 (2.0%) EBVaGC cases and not found in TW cases. The distributions were significantly different (P < 0.05). Other five isolates (one NPC, one EBVaGC and three TW cases) showed different sequences and could not be assigned to any of the three groups. Type 1 EBV strains showed heterogeneous in terms of EBER variants. These results suggest that EBER locus can be useful to identify different EBV isolates, and it would be interesting to evaluate the association of EBER polymorphisms with EBV‐associated tumors. J. Med. Virol. 82: 829–836, 2010. © 2010 Wiley‐Liss, Inc.