bluuebunny/crossref_metadata_2025 huggingface dataset:
Characterization of enriched aerotolerant cellulose-degrading communities for biofuels production using differing selection pressures and inoculum sources
Authors: Wushke Scott , Levin David B. , Cicek Nazim , Sparling Richard
Published: August 2013

Ethanol production from direct cellulose fermentation has mainly been described as a strictly anaerobic process. The use of air-tolerant organisms or consortia for this process would reduce the need for prereduction of the medium and also permit continuous feed of aerobic feedstock. To this end, moderately thermophilic (60 °C) consortia of fermentative, cellulolytic bacteria were enriched from 3 distinct environments (manure, marsh, and rotten wood) from a farm in southeast Saskatchewan, Canada. Community phenotypic and metabolic profiles were characterized. Selection methods included direct plating under an aerobic atmosphere and repeated passaging; the methods were designed to select for robust, stable aerotolerant cellulose-degrading communities. Several of the isolated communities exhibited an increase in total cellulose degradation and total ethanol yield when compared with a monoculture of Clostridium thermocellum DSMZ 1237. Owing to stringent selection conditions, low diversity enrichments were found, and many appeared to be binary cultures via density gradient gel electrophoresis analysis. On the basis of 16S rRNA gene sequencing, aerobic conditions selected for a mix of organisms highly related to C. thermocellum and Geobacillus species, while anaerobic conditions led to the development of consortia containing strains related to C. thermocellum with strains from either the genus Geobacillus or the genus Thermoanaerobacter. The presence of a Geobacillus-like species appeared to be a prerequisite for aerotolerance of the cellulolytic enrichments, a highly desired phenotype in lignocellulosic consolidated bioprocessing.
Modulation of arginine and asymmetric dimethylarginine concentrations in liver and plasma by exogenous hydrogen sulfide in LPS-induced endotoxemia
Authors: Bekpinar Seldag , Develi-Is Seval , Unlucerci Yesim , Kusku-Kiraz Zeynep , Uysal Mujdat , Gurdol Figen
Published: August 2013

Plasma levels of asymmetric dimethylarginine (ADMA) are known to be elevated under pathological conditions, but reports on intracellular ADMA levels are scarce. In this study, we investigated whether lipopolysaccharide (LPS)-induced endotoxemia alters the intra- and extra-cellular partition of l-arginine and ADMA. The effect of H2S pretreatment was also researched. Wistar rats were given sodium hydrogen sulfide (NaHS, 1 mg·(kg body mass)−1) one hour before the LPS injections (20 mg·kg−1). Six hours after the LPS treatment, the animals were sacrificed. Myeloperoxidase (MPO) and dimethylarginine dimethylaminohydrolase (DDAH) activities and levels of hypoxia-inducible factor (HIF)-1α were measured in the liver. ADMA and arginine levels were determined using HPLC. LPS injection caused liver injury, as evidenced by the activities of alanine transaminase, aspartate transaminase, and arginase. LPS increased l-arginine content and decreased DDAH activity in the rat liver. MPO activity and HIF-1α levels indicated inflammation and hypoxia. Despite the accumulation of ADMA in the plasma, the level remained unchanged in the liver. NaHS pretreatment restored both the DDAH activity and intracellular l-arginine levels. It is concluded that increased H2S generation has a potency to restore hepatic l-arginine levels and ADMA handling in endotoxemia. Extra- and intra-cellular partitions of ADMA seem to depend on transport proteins as well as the DDAH activity.
HYBRID DECISION TREE ARCHITECTURE UTILIZING LOCAL SVMs FOR EFFICIENT MULTI-LABEL LEARNING
Authors: GJORGJEVIKJ DEJAN , MADJAROV GJORGJI , DŽEROSKI SAŠO
Published: August 2013

Multi-label learning (MLL) problems abound in many areas, including text categorization, protein function classification, and semantic annotation of multimedia. Issues that severely limit the applicability of many current machine learning approaches to MLL are the large-scale problem, which have a strong impact on the computational complexity of learning. These problems are especially pronounced for approaches that transform MLL problems into a set of binary classification problems for which Support Vector Machines (SVMs) are used. On the other hand, the most efficient approaches to MLL, based on decision trees, have clearly lower predictive performance. We propose a hybrid decision tree architecture, where the leaves do not give multi-label predictions directly, but rather utilize local SVM-based classifiers giving multi-label predictions. A binary relevance architecture is employed in the leaves, where a binary SVM classifier is built for each of the labels relevant to that particular leaf. We use a broad range of multi-label datasets with a variety of evaluation measures to evaluate the proposed method against related and state-of-the-art methods, both in terms of predictive performance and time complexity. Our hybrid architecture on almost every large classification problem outperforms the competing approaches in terms of the predictive performance, while its computational efficiency is significantly improved as a result of the integrated decision tree.
A UNIFIED FRAMEWORK FOR JOINT VIDEO PEDESTRIAN SEGMENTATION AND POSE TRACKING
Authors: LI YANLI , ZHOU ZHONG , WU WEI
Published: August 2013

Pedestrian segmentation and pose tracking are performed to infer human silhouettes and skeletons, respectively. Although the two tasks are complementary in nature, few works have been done on combining them together to improve each other, and some related methods are limited to still images. In this paper, we propose an approach to jointly solving them in monocular videos via a unified framework. Basically, the framework is built on EM-based maximum likelihood estimation, in which pose tracking is fulfilled through Bayesian filtering using body silhouette as an observation cue, and pedestrian segmentation is inferred by guided filtering with constraint of body skeleton. The two sets of parameters are alternatively updated along the video. In the initialization of the framework, we utilize a hierarchical shape matching scheme to obtain the silhouette and skeleton in the first frame. Experiments on challenging pedestrian datasets verify the approach's effectiveness to cluttered backgrounds, moving camera and various articulated bodies, and the performance is improved significantly by solving the two tasks together.
EXTREME-POINT SYMMETRIC MODE DECOMPOSITION METHOD FOR DATA ANALYSIS
Authors: WANG JIN-LIANG , LI ZONG-JUN
Published: August 2013

An extreme-point symmetric mode decomposition (ESMD) method is proposed to improve the Hilbert–Huang Transform (HHT) through the following prospects: (1) The sifting process is implemented by the aid of 1, 2, 3 or more inner interpolating curves, which classifies the methods into ESMD_I, ESMD_II, ESMD_III, and so on; (2) The last residual is defined as an optimal curve possessing a certain number of extreme points, instead of general trend with at most one extreme point, which allows the optimal sifting times and decompositions; (3) The extreme-point symmetry is applied instead of the envelop symmetry; (4) The data-based direct interpolating approach is developed to compute the instantaneous frequency and amplitude. One advantage of the ESMD method is to determine an optimal global mean curve in an adaptive way which is better than the common least-square method and running-mean approach; another one is to determine the instantaneous frequency and amplitude in a direct way which is better than the Hilbert-spectrum method. These will improve the adaptive analysis of the data from atmospheric and oceanic sciences, informatics, economics, ecology, medicine, seismology, and so on.
Fischer Black
Authors: Merton Robert C. , Scholes Myron S.
Published: August 2013

Reprint

This article was originally published by Wiley for the American Finance Association (Merton RC, Scholes MS. 1995. Fischer Black. J. Finance 50(5):1359–70). It is reprinted with permission from John Wiley and Sons © 1995. Reference formatting was updated to facilitate linking.
Dynamics of Swirling Flames
Authors: Candel Sébastien , Durox Daniel , Schuller Thierry , Bourgouin Jean-François , Moeck Jonas P.
Published: August 2013

In many continuous combustion processes, such as those found in aeroengines or gas turbines, the flame is stabilized by a swirling flow formed by aerodynamic swirlers. The dynamics of such swirling flames is of technical and fundamental interest. This article reviews progress in this field and begins with a discussion of the swirl number, a parameter that plays a central role in the definition of the flow structure and its response to incoming disturbances. Interaction between the swirler response and incoming acoustic perturbations generates a vorticity wave convected by the flow, which is accompanied by azimuthal velocity fluctuations. Axial and azimuthal velocities in turn define the flame response in terms of heat--release rate fluctuations. The nonlinear response of swirling flames to incoming disturbances is conveniently represented with a flame describing function (FDF), in other words, with a family of transfer functions depending on frequency and incident axial velocity amplitudes. The FDF, however, does not reflect all possible nonlinear interactions in swirling flows. This aspect is illustrated with experimental data and some theoretical arguments in the last part of this article, which concerns the interaction of incident acoustic disturbances with the precessing vortex core, giving rise to nonlinear fluctuations at the frequency difference.
Special Interests AfterCitizens United: Access, Replacement, and Interest Group Response to Legal Change
Authors: Issacharoff Samuel , Peterman Jeremy
Published: August 2013

The legal literature on campaign finance law and the political science literature on how and why interest groups mobilize use different methodologies to get at overlapping issues. This review integrates some of these insights to better understand the relationship between interest group participation in elections and changes in campaign finance law. The post–Citizens United world of law created regulatory vacuums that only certain groups tried to take advantage of. For example, little corporate money found its way into Super PACs or groups engaging in independent electoral advocacy. We argue that ascertaining interest groups' objectives of either using contributions to candidates to obtain access, on one hand, or using independent expenditures to install friendly candidates in office, on the other, is key to understanding how interest groups respond to legal developments. We also argue that although interest group participation in elections increased in 2012, the party-centric federal election system was largely resilient to increased interest group mobilizations, highlighting the difficulties with the replacement strategy.
Antagonistic Coevolution of Marine Planktonic Viruses and Their Hosts
Authors: Martiny Jennifer B.H. , Riemann Lasse , Marston Marcia F. , Middelboe Mathias
Published: August 2013

The potential for antagonistic coevolution between marine viruses and their (primarily bacterial) hosts is well documented, but our understanding of the consequences of this rapid evolution is in its infancy. Acquisition of resistance against co-occurring viruses and the subsequent evolution of virus host range in response have implications for bacterial mortality rates as well as for community composition and diversity. Drawing on examples from a range of environments, we consider the potential dynamics, underlying genetic mechanisms and fitness costs, and ecological impacts of virus-host coevolution in marine waters. Given that much of our knowledge is derived from laboratory experiments, we also discuss potential challenges and approaches in scaling up to diverse, complex networks of virus-host interactions. Finally, we note that a variety of novel approaches for characterizing virus-host interactions offer new hope for a mechanistic understanding of antagonistic coevolution in marine plankton.
The Oceanography and Ecology of the Ross Sea
Authors: Smith Walker O. , Ainley David G. , Arrigo Kevin R. , Dinniman Michael S.
Published: August 2013

The continental shelf of the Ross Sea exhibits substantial variations in physical forcing, ice cover, and biological processes on a variety of time and space scales. Its circulation is characterized by advective inputs from the east and exchanges with off-shelf regions via the troughs along the northern portions. Phytoplankton biomass is greater there than anywhere else in the Antarctic, although nitrate is rarely reduced to levels below 10 μmol L−1. Overall growth is regulated by irradiance (via ice at the surface and by the depths of the mixed layers) and iron concentrations. Apex predators reach exceptional abundances, and the world's largest colonies of Adélie and emperor penguins are found there. Krill are represented by two species (Euphausia superba near the shelf break and Euphausia crystallorophias throughout the continental shelf region). Equally important and poorly known is the Antarctic silverfish (Pleuragramma antarcticum), which is also consumed by most upper-trophic-level predators. Future changes in the Ross Sea environment will have profound and unpredictable effects on the food web.
Benthic Exchange and Biogeochemical Cycling in Permeable Sediments
Authors: Huettel Markus , Berg Peter , Kostka Joel E.
Published: August 2013

The sandy sediments that blanket the inner shelf are situated in a zone where nutrient input from land and strong mixing produce maximum primary production and tight coupling between water column and sedimentary processes. The high permeability of the shelf sands renders them susceptible to pressure gradients generated by hydrodynamic and biological forces that modulate spatial and temporal patterns of water circulation through these sediments. The resulting dynamic three-dimensional patterns of particle and solute distribution generate a broad spectrum of biogeochemical reaction zones that facilitate effective decomposition of the pelagic and benthic primary production products. The intricate coupling between the water column and sediment makes it challenging to quantify the production and decomposition processes and the resultant fluxes in permeable shelf sands. Recent technical developments have led to insights into the high biogeochemical and biological activity of these permeable sediments and their role in the global cycles of matter.
The Pathogenesis of Chronic Lymphocytic Leukemia
Authors: Zhang Suping , Kipps Thomas J.
Published: August 2013

Chronic lymphocytic leukemia (CLL) is characterized by the clonal expansion of CD5+CD23+ B cells in blood, marrow, and second lymphoid tissues. Gene-expression profiling and phenotypic studies suggest that CLL is probably derived from CD5+ B cells similar to those found in the blood of healthy adults. Next-generation sequencing has revealed recurrent genetic lesions that are implicated in CLL pathogenesis and/or disease progression. The biology of CLL is entwined with its microenvironment, in which accessory cells can promote leukemia cell growth and/or survival. Recently, much attention has been focused on the CLL B cell receptor (BCR) and on chemokine receptors that enable CLL cells to home to lymphoid tissues and to establish the leukemia microenvironment. Agents that can interfere with BCR signaling or chemokine–receptor signaling, or that target surface antigens selectively expressed on CLL cells, promise to have significant therapeutic benefit in patients with this disease.
Mammalian Pheromones
Authors: Liberles Stephen D.
Published: August 2013

Mammalian pheromones control a myriad of innate social behaviors and acutely regulate hormone levels. Responses to pheromones are highly robust, reproducible, and stereotyped and likely involve developmentally predetermined neural circuits. Here, I review several facets of pheromone transduction in mammals, including (a) chemosensory receptors and signaling components of the main olfactory epithelium and vomeronasal organ involved in pheromone detection; (b) pheromone-activated neural circuits subject to sex-specific and state-dependent modulation; and (c) the striking chemical diversity of mammalian pheromones, which range from small, volatile molecules and sulfated steroids to large families of proteins. Finally, I review (d) molecular mechanisms underlying various behavioral and endocrine responses, including modulation of puberty and estrous; control of reproduction, aggression, suckling, and parental behaviors; individual recognition; and distinguishing of own species from predators, competitors, and prey. Deconstruction of pheromone transduction mechanisms provides a critical foundation for understanding how odor response pathways generate instinctive behaviors.
Dynamic Treatment Regimes
Authors: Chakraborty Bibhas , Murphy Susan A.
Published: August 2013

A dynamic treatment regime consists of a sequence of decision rules, one per stage of intervention, that dictate how to individualize treatments to patients, based on evolving treatment and covariate history. These regimes are particularly useful for managing chronic disorders and fit well into the larger paradigm of personalized medicine. They provide one way to operationalize a clinical decision support system. Statistics plays a key role in the construction of evidence-based dynamic treatment regimes—informing the best study design as well as efficient estimation and valid inference. Owing to the many novel methodological challenges this area offers, it has been growing in popularity among statisticians in recent years. In this article, we review the key developments in this exciting field of research. In particular, we discuss the sequential multiple assignment randomized trial designs, estimation techniques like Q-learning and marginal structural models, and several inference techniques designed to address the associated nonstandard asymptotics. We reference software whenever available. We also outline some important future directions.
Enhanced K+ secretion in dextran sulfate-induced colitis reflects upregulation of large conductance apical K+ channels (BK; Kcnma1)
Authors: Kanthesh Basalingappa M. , Sandle Geoffrey I. , Rajendran Vazhaikkurichi M.
Published: August 2013

Defective colonic Na+ and Cl− absorption is a feature of active ulcerative colitis (UC), but little is known about changes in colonic K+ transport. We therefore investigated colonic K+ transport in a rat model of dextran sulfate-induced colitis. Colitis was induced in rat distal colon using 5% dextran sulfate sodium (DSS). Short-circuit current ( Isc, indicating electrogenic ion transport) and 86Rb (K+ surrogate) fluxes were measured in colonic mucosa mounted in Ussing chambers under voltage-clamp conditions in the presence of mucosal orthovanadate (a P-type ATPase inhibitor). Serum aldosterone was measured by immunoassay. Control animals exhibited zero net K+ flux. By contrast, DSS-treated animals exhibited active K+ secretion, which was inhibited by 98, 76, and 22% by Ba2+ (nonspecific K+ channel blocker), iberiotoxin (IbTX; BK channel blocker), and TRAM-34 (IK channel blocker), respectively. Apical BK channel α-subunit mRNA abundance and protein expression, and serum aldosterone levels in DSS-treated animals, were enhanced 6-, 3-, and 6-fold respectively, compared with controls. Increasing intracellular Ca2+ with carbachol (CCH), or intracellular cAMP with forskolin (FSK), stimulated both active Cl− secretion and active K+ secretion in controls but had no or little effect in DSS-treated animals. In DSS-induced colitis, active K+ secretion involves upregulation of apical BK channel expression, which may be aldosterone-dependent, whereas Cl− secretion is diminished. Since similar ion transport abnormalities occur in patients with UC, diarrhea in this disease may reflect increased colonic K+ secretion (rather than increased Cl− secretion), as well as defective Na+ and Cl− absorption.
Effect of apical hyperosmotic sodium challenge and amiloride on sodium transport in human bronchial epithelial cells from cystic fibrosis donors
Authors: Rasgado-Flores Hector , Krishna Mandava Vamsi , Siman Homayoun , Van Driessche Willy , Pilewski Joseph M. , Randell Scott H. , Bridges Robert J.
Published: August 2013

Hypertonic saline (HS) inhalation therapy benefits cystic fibrosis (CF) patients [Donaldson SH, Bennet WD, Zeman KL, Knowles MR, Tarran R, Boucher RC. N Engl J Med 354: 241–250, 2006; Elkins MR, Robinson M, Rose BR, Harbour C, Moriarty CP, Marks GB, Belousova EG, Xuan W, Bye PT; the National Hypertonic Saline in Cystic Fibrosis (NHSCF) Study Group. N Engl J Med 354: 229–240, 2006]. Surprisingly, these benefits are long-lasting and are diminished by the epithelial Na+ channel blocker amiloride (Donaldson SH, Bennet WD, Zeman KL, Knowles MR, Tarran R, Boucher RC. N Engl J Med 354: 241–250, 2006). Our aim was to explain these effects. Human bronchial epithelial (hBE) cells from CF lungs were grown in inserts and were used in three experimental approaches: 1) Ussing chambers to measure amiloride-sensitive short-circuit currents ( INa); 2) continuous perfusion Ussing chambers; and 3) near “thin-film” conditions in which the airway surface of the inserts was exposed to a small volume (30 μl) of isosmotic or HS solution as the inserts were kept in their incubation tray and were subsequently used to measure INa under isosmotic conditions (near thin-film experiments; Tarran R, Boucher RC. Methods Mol Med 70: 479–492, 2002). HS solutions (660 mosmol/kgH2O) were prepared by adding additional NaCl to the isosmotic buffer. The transepithelial short-circuit current ( ISC), conductance ( GT), and capacitance ( CT) were measured by transepithelial impedance analysis (Danahay H, Atherton HC, Jackson AD, Kreindler JL, Poll CT, Bridges RJ. Am J Physiol Lung Cell Mol Physiol 290: L558–L569, 2006; Singh AK, Singh S, Devor DC, Frizzell RA, van Driessche W, Bridges RJ. Methods Mol Med 70: 129–142, 2002). Exposure to apical HS inhibited INa, GT, and CT. The INa inhibition required 60 min of reexposure to the isosmotic solution to recover 75%. The time of exposure to HS required to inhibit INa was <2.5 min. Under near thin-film conditions, apical exposure to HS inhibited INa, but as osmotically driven water moved to the apical surface, the aqueous apical volume increased, leading to an amiloride-insensitive decrease in its osmolality and to recovery of INa that lagged behind the osmotic recovery. Amiloride significantly accelerated the recovery of INa following exposure to HS. Our conclusions are that exposure to HS inhibits hBE INa and that amiloride diminishes this effect.
Organic anion transporting polypeptide 1B transporters modulate hydroxyurea pharmacokinetics
Authors: Walker Aisha L. , Lancaster Cynthia S. , Finkelstein David , Ware Russell E. , Sparreboom Alex
Published: August 2013

Hydroxyurea is currently the only FDA-approved drug that ameliorates the pathophysiology of sickle cell anemia. Unfortunately, substantial interpatient variability in the pharmacokinetics (PK) of hydroxyurea may result in variation of the drug's efficacy. However, little is known about mechanisms that modulate hydroxyurea PK. Recent in vitro studies identifying hydroxyurea as a substrate for organic anion transporting polypeptide (OATP1B) transporters prompted the current investigation assessing the role of OATP1B transporters in modulating hydroxyurea PK. Using wild-type and Oatp1b knockout (Oatp1b−/−) mice, hydroxyurea PK was analyzed in vivo by measuring [14C]hydroxyurea distribution in plasma, kidney, liver, urine, or the exhaled 14CO2 metabolite. Plasma levels were significantly reduced by 20% in Oatp1b−/− mice compared with wild-type (area under the curve of 38.64 or 48.45 μg·h−1·ml−1, respectively) after oral administration, whereas no difference was observed between groups following intravenous administration. Accumulation in the kidney was significantly decreased by twofold in Oatp1b−/− mice (356.9 vs. 748.1 pmol/g), which correlated with a significant decrease in urinary excretion. Hydroxyurea accumulation in the liver was also decreased (136.6 vs. 107.3 pmol/g in wild-type or Oatp1b−/− mice, respectively) correlating with a decrease in exhaled 14CO2. These findings illustrate that deficiency of Oatp1b transporters alters the absorption, distribution, and elimination of hydroxyurea thus providing the first in vivo evidence that cell membrane transporters may play a significant role in modulating hydroxyurea PK. Future studies to investigate other transporters and their role in hydroxyurea disposition are warranted for understanding the sources of variation in hydroxyurea's PK.
Coronary endothelial dysfunction and mitochondrial reactive oxygen species in type 2 diabetic mice
Authors: Cho Young-Eun , Basu Aninda , Dai Anzhi , Heldak Michael , Makino Ayako
Published: August 2013

Endothelial cell (EC) dysfunction is implicated in cardiovascular diseases, including diabetes. The decrease in nitric oxide (NO) bioavailability is the hallmark of endothelial dysfunction, and it leads to attenuated vascular relaxation and atherosclerosis followed by a decrease in blood flow. In the heart, decreased coronary blood flow is responsible for insufficient oxygen supply to cardiomyocytes and, subsequently, increases the incidence of cardiac ischemia. In this study we investigate whether and how reactive oxygen species (ROS) in mitochondria contribute to coronary endothelial dysfunction in type 2 diabetic (T2D) mice. T2D was induced in mice by a high-fat diet combined with a single injection of low-dose streptozotocin. ACh-induced vascular relaxation was significantly attenuated in coronary arteries (CAs) from T2D mice compared with controls. The pharmacological approach reveals that NO-dependent, but not hyperpolarization- or prostacyclin-dependent, relaxation was decreased in CAs from T2D mice. Attenuated ACh-induced relaxation in CAs from T2D mice was restored toward control level by treatment with mitoTempol (a mitochondria-specific O2− scavenger). Coronary ECs isolated from T2D mice exhibited a significant increase in mitochondrial ROS concentration and decrease in SOD2 protein expression compared with coronary ECs isolated from control mice. Furthermore, protein ubiquitination of SOD2 was significantly increased in coronary ECs isolated from T2D mice. These results suggest that augmented SOD2 ubiquitination leads to the increase in mitochondrial ROS concentration in coronary ECs from T2D mice and attenuates coronary vascular relaxation in T2D mice.
Multiple cell death pathways are independently activated by lethal hypertonicity in renal epithelial cells
Authors: Choi Soo Youn , Lee-Kwon Whaseon , Lee Hwan Hee , Lee Jun Ho , Sanada Satoru , Kwon Hyug Moo
Published: August 2013

When hypertonicity is imposed with sufficient intensity and acuteness, cells die. Here we investigated the cellular pathways involved in death using a cell line derived from renal epithelium. We found that hypertonicity rapidly induced activation of an intrinsic cell death pathway—release of cytochrome c and activation of caspase-3 and caspase-9—and an extrinsic pathway—activation of caspase-8. Likewise, a lysosomal pathway of cell death characterized by partial lysosomal rupture and release of cathepsin B from lysosomes to the cytosol was also activated. Relationships among the pathways were examined using specific inhibitors. Caspase inhibitors did not affect cathepsin B release into the cytosol by hypertonicity. In addition, cathepsin B inhibitors and caspase inhibitors did not affect hypertonicity-induced cytochrome c release, suggesting that the three pathways were independently activated. Combined inhibition of caspases and cathepsin B conferred significantly more protection from hypertonicity-induced cell death than inhibition of caspase or cathepsin B alone, indicating that all the three pathways contributed to the hypertonicity-induced cell death. Similar pattern of sensitivity to the inhibitors was observed in two other cell lines derived from renal epithelia. We conclude that multiple cell death pathways are independently activated early in response to lethal hypertonic stress in renal epithelial cells.
Angiotensin II-induced hypertension increases plasma membrane Na pump activity by enhancing Na entry in rat thick ascending limbs
Authors: Gonzalez-Vicente Agustin , Garvin Jeffrey L.
Published: August 2013

Thick ascending limbs (TAL) reabsorb 30% of the filtered NaCl load. Na enters the cells via apical Na-K-2Cl cotransporters and Na/H exchangers and exits via basolateral Na pumps. Chronic angiotensin II (ANG II) infusion increases net TAL Na transport and Na apical entry; however, little is known about its effects on the basolateral Na pump. We hypothesized that in rat TALs Na pump activity is enhanced by ANG II-infusion, a model of ANG II-induced hypertension. Rats were infused with 200 ng·kg−1·min−1ANG II or vehicle for 7 days, and TAL suspensions were obtained. We studied plasma membrane Na pump activity by measuring changes in 1) intracellular Na (Nai) induced by ouabain; and 2) ouabain-sensitive oxygen consumption (QO2). We found that the ouabain-sensitive rise in Naiin TALs from ANG II-infused rats was 12.8 ± 0.4 arbitrary fluorescent units (AFU)·mg−1·min−1compared with only 9.9 ± 1.1 AFU·mg−1·min−1in controls ( P < 0.024). Ouabain-sensitive oxygen consumption was 17 ± 5% ( P < 0.043) greater in tubules from ANG II-treated than vehicle rats. ANG II infusion did not alter total Na pump expression, the number of Na pumps in the plasma membrane, or the affinity for Na. When furosemide (1.1 mg·kg−1·day−1) was coinfused with ANG II, no increase in plasma membrane Na pump activity was observed. We concluded that in ANG II-induced hypertension Na pump activity is increased in the plasma membrane of TALs and that this increase is caused by the chronically enhanced Na entry occurring in this model.
K+-induced natriuresis is preserved during Na+depletion and accompanied by inhibition of the Na+-Cl−cotransporter
Authors: van der Lubbe Nils , Moes Arthur D. , Rosenbaek Lena L. , Schoep Sharon , Meima Marcel E. , Danser Alexander H. J. , Fenton Robert A. , Zietse Robert , Hoorn Ewout J.
Published: August 2013

During hypovolemia and hyperkalemia, the kidneys defend homeostasis by Na+retention and K+secretion, respectively. Aldosterone mediates both effects, but it is unclear how the same hormone can evoke such different responses. To address this, we mimicked hypovolemia and hyperkalemia in four groups of rats with a control diet, low-Na+diet, high-K+diet, or combined diet. The low-Na+and combined diets increased plasma and kidney ANG II. The low-Na+and high-K+diets increased plasma aldosterone to a similar degree (3-fold), whereas the combined diet increased aldosterone to a greater extent (10-fold). Despite similar Na+intake and higher aldosterone, the high-K+and combined diets caused a greater natriuresis than the control and low-Na+diets, respectively ( P < 0.001 for both). This K+-induced natriuresis was accompanied by a decreased abundance but not phosphorylation of the Na+-Cl−cotransporter (NCC). In contrast, the epithelial Na+channel (ENaC) increased in parallel with aldosterone, showing the highest expression with the combined diet. The high-K+and combined diets also increased WNK4 but decreased Nedd4-2 in the kidney. Total and phosphorylated Ste-20-related kinase were also increased but were retained in the cytoplasm of distal convoluted tubule cells. In summary, high dietary K+overrides the effects of ANG II and aldosterone on NCC to deliver sufficient Na+to ENaC for K+secretion. K+may inhibit NCC through WNK4 and help activate ENaC through Nedd4-2.
Cellular localization of adenine receptors in the rat kidney and their functional significance in the inner medullary collecting duct
Authors: Kishore Bellamkonda K. , Zhang Yue , Gevorgyan Haykanush , Kohan Donald E. , Schiedel Anke C. , Müller Christa E. , Peti-Peterdi János
Published: August 2013

The Gi-coupled adenine receptor (AdeR) binds adenine with high affinity and potentially reduces cellular cAMP levels. Since cAMP is an important second messenger in the renal transport of water and solutes, we localized AdeR in the rat kidney. Real-time RT-PCR showed higher relative expression of AdeR mRNA in the cortex and outer medulla compared with the inner medulla. Immunoblots using a peptide-derived and affinity-purified rabbit polyclonal antibody specific for an 18-amino acid COOH-terminal sequence of rat AdeR, which we generated, detected two bands between ∼30 and 40 kDa (molecular mass of native protein: 37 kDa) in the cortex, outer medulla, and inner medulla. These bands were ablated by preadsorption of the antibody with the immunizing peptide. Immunofluorescence labeling showed expression of AdeR protein in all regions of the kidney. Immunoperoxidase revealed strong labeling of AdeR protein in the cortical vasculature, including the glomerular arterioles, and less intense labeling in the cells of the collecting duct system. Confocal immunofluorescence imaging colocalized AdeR with aquaporin-2 protein to the apical plasma membrane in the collecting duct. Functionally, adenine (10 μM) significantly decreased ( P < 0.01) 1-deamino-8-d-arginine vasopressin (10 nM)-induced cAMP production in ex vivo preparations of inner medullary collecting ducts, which was reversed by PSB-08162 (20 μM, P < 0.01), a selective antagonist of AdeR. Thus, we demonstrated the expression of AdeR in the renal vasculature and collecting ducts and its functional relevance. This study may open a new avenue for the exploration of autocrine/paracrine regulation of renal vascular and tubular functions by the nucleobase adenine in health and disease.
CXCR2 knockout mice are protected against DSS-colitis-induced acute kidney injury and inflammation
Authors: Ranganathan Punithavathi , Jayakumar Calpurnia , Manicassamy Santhakumar , Ramesh Ganesan
Published: August 2013

Organ cross talk exists in many diseases of the human and animal models of human diseases. A recent study demonstrated that inflammatory mediators can cause acute kidney injury and neutrophil infiltration in a mouse model of dextran sodium sulfate (DSS)-colitis. However, the chemokines and their receptors that may mediate distant organ effects in colitis are unknown. We hypothesized that keratinocyte chemoattractant (KC)/IL-8 receptor chemokine (C-X-C motif) ligand 2 (CXCL2) mediates DSS-colitis-induced acute kidney injury. Consistent with our hypothesis, wild-type (WT) mice developed severe colitis with DSS treatment, which was associated with inflammatory cytokine and chemokine expression and neutrophil infiltration in the colon. DSS-colitis in WT was accompanied by acute kidney injury and enhanced expression of inflammatory cytokines in the kidney. However, CXCR2 knockout mice were protected against DSS-colitis as well as acute kidney injury. Moreover, the expression of cytokines and chemokines and neutrophil infiltration was blunted in CXCR2 knockout mice in the colon and kidney. Administration of recombinant KC exacerbated DSS-colitis-induced acute kidney injury. Our results suggest that KC/IL-8 and its receptor CXCR2 are critical and major mediators of organ cross talk in DSS colitis and neutralization of CXCR2 will help to reduce the incidence of acute kidney injury due to ulcerative colitis and Crohn's disease in humans.
Direct inhibition of basolateral Kir4.1/5.1 and Kir4.1 channels in the cortical collecting duct by dopamine
Authors: Zaika Oleg L. , Mamenko Mykola , Palygin Oleg , Boukelmoune Nabila , Staruschenko Alexander , Pochynyuk Oleh
Published: August 2013

It is recognized that dopamine promotes natriuresis by inhibiting multiple transporting systems in the proximal tubule. In contrast, less is known about the molecular targets of dopamine actions on water-electrolyte transport in the cortical collecting duct (CCD). Epithelial cells in the CCD are exposed to dopamine, which is synthesized locally or secreted from sympathetic nerve endings. Basolateral K+channels in the distal renal tubule are critical for K+recycling and controlling basolateral membrane potential to establish the driving force for Na+reabsorption. Here, we demonstrate that Kir4.1 and Kir5.1 are highly expressed in the mouse kidney cortex and are localized to the basolateral membrane of the CCD. Using patch-clamp electrophysiology in freshly isolated CCDs, we detected highly abundant 40-pS and scarce 20-pS single channel conductances, most likely representing Kir4.1/5.1 and Kir4.1 channels, respectively. Dopamine reversibly decreased the open probability of both channels, with a relatively greater action on the Kir4.1/5.1 heterodimer. This effect was mediated by D2-like but not D1-like dopamine receptors. PKC blockade abolished the inhibition of basolateral K+channels by dopamine. Importantly, dopamine significantly decreased the amplitude of Kir4.1/5.1 and Kir4.1 unitary currents. Consistently, dopamine induced an acute depolarization of basolateral membrane potential, as directly monitored using current-clamp mode in isolated CCDs. Therefore, we demonstrate that dopamine inhibits basolateral Kir4.1/5.1 and Kir4.1 channels in CCD cells via stimulation of D2-like receptors and subsequently PKC. This leads to depolarization of the basolateral membrane and a decreased driving force for Na+reabsorption in the distal renal tubule.
Saccades curve away from previously inhibited locations: evidence for the role of priming in oculomotor competition
Authors: Belopolsky Artem V. , Van der Stigchel Stefan
Published: August 2013

The oculomotor system serves as the basis for representing concurrently competing motor programs. Here, we examine whether the oculomotor system also keeps track of the outcome of competition between target and distractor on the previous trial. Participants had to perform a simple task of making a saccade toward a predefined direction. On two-thirds of the trials, an irrelevant distractor was presented to either the left or right of the fixation. On one-third of the trials, no distractor was present. The results show that on trials without a distractor, saccades curved away from the empty location that was occupied by a distractor on the previous trial. This result was replicated and extended to cases when different saccade directions were used. In addition, we show that repetition of distractor location on the distractor-present trials results in a stronger curvature away and in a shorter saccade latency to the target. Taken together, these results provide strong evidence that the oculomotor system automatically codes and retains locations that had been ignored in the past to bias future behavior.
Relationship between Malnutrition and the Number of Permanent Teeth in Filipino 10- to 13-Year-Olds
Authors: Heinrich-Weltzien Roswitha , Zorn Carsten , Monse Bella , Kromeyer-Hauschild Katrin
Published: August 2013

In the present study, we determined whether there is a delay in the eruption of permanent teeth (PT) among Filipino adolescents with stunting or thinness. Height, weight, and number of PT were recorded in 1554 Filipino 10- to 13-year-olds (711 boys; 843 girls).z-scores for height (HAZ) and body mass index (BMI) were calculated according to the WHO growth reference, and their correlations to the number of PT were assessed. 54.9% of the children have at least one form of malnutrition. Significantly, more boys (22.9%) than girls (16.5%) were thin, while no sex difference in stunting was noted (boys 48.5%; girls 44.0%). The number of PT was significantly correlated to HAZ and BMI-z-score. Stunted and thin students had significantly fewer PT than their nonaffected peers. These differences tended to be the result of delay in tooth eruption in thin and stunted adolescents. In 13-year-old girls, all PT were erupted regardless of their nutritional status indicating a catch-up. Thin and stunted boys had one tooth less than normal boys at this age. Impaired physical growth and dental development seem to have common risk factors. Therefore, regular monitoring of growth and dental development might be helpful for targeting support programmes in developing countries.
Raman Spectra of High‐κ Dielectric Layers Investigated with Micro‐Raman Spectroscopy Comparison with Silicon Dioxide
Authors: Borowicz P. , Taube A. , Rzodkiewicz W. , Latek M. , Gierałtowska S.
Published: August 2013

Three samples with dielectric layers from high‐κ dielectrics, hafnium oxide, gadolinium‐silicon oxide, and lanthanum‐lutetium oxide on silicon substrate were studied by Raman spectroscopy. The results obtained for high‐κ dielectrics were compared with spectra recorded for silicon dioxide. Raman spectra suggest the similarity of gadolinium‐silicon oxide and lanthanum‐lutetium oxide to the bulk nondensified silicon dioxide. The temperature treatment of hafnium oxide shows the evolution of the structure of this material. Raman spectra recorded for as-deposited hafnium oxide are similar to the results obtained for silicon dioxide layer. After thermal treatment especially at higher temperatures (600°C and above), the structure of hafnium oxide becomes similar to the bulk non‐densified silicon dioxide.
Plasma and Ocular Prednisolone Disposition after Oral Treatment in Cats
Authors: Del Sole María J. , Schaiquevich Paula , Aba Marcelo A. , Lanusse Carlos E. , Moreno Laura
Published: August 2013

Objective. To evaluate the plasma and aqueous humor disposition of prednisolone after oral administration in cats.Methods. Six cats were administered with a single oral dose of prednisolone (10 mg). Blood and aqueous humor samples were serially collected after drug administration. Prednisolone concentrations in plasma and aqueous humor were measured at 0.25, 0.5, 1.0, 1.5, 2.0, 3.0, 4.0, and 5.0 h after administration by a high-performance liquid chromatographic analytical method developed and validated for this purpose.Results. Mean ± standard error (SE) of maximum plasma prednisolone concentration (300.8 ± 67.3 ng/mL) was reached at 1 h after administration. Prednisolone was distributed to the aqueous humor reaching a mean peak concentration of 100.9 ± 25.5 ng/mL at 1.25 h after administration. The mean ± SE systemic and aqueous humor exposure (AUC) was 553.3 ± 120.0 ng*h/mL and 378.8 ± 64.9 ng*h/mL, respectively. A highAUCaqueous humor/AUCplasmaratio was observed (0.68 ± 0.13). The mean half-life time of elimination in plasma and aqueous humor was 0.87 ± 0.16 h and 2.25 ± 0.44 h, respectively.Clinical Significance. The observed high ratio between aqueous humor and plasma prednisolone concentrations indicates that extensive penetration of prednisolone to the anterior segment of the eye may occur. This is the first step that contributes to the optimization of the pharmacological therapeutics for the clinical treatment of uveitis.
A Determinant Expression for the Generalized Bessel Polynomials
Authors: Yang Sheng-liang , Zheng Sai-nan
Published: August 2013

Using the exponential Riordan arrays, we show that a variation of the generalized Bessel polynomial sequence is of Sheffer type, and we obtain a determinant formula for the generalized Bessel polynomials. As a result, the Bessel polynomial is represented as determinant the entries of which involve Catalan numbers.
Spectrum of Discrete Second-Order Neumann Boundary Value Problems with Sign-Changing Weight
Authors: Ma Ruyun , Gao Chenghua , Lu Yanqiong
Published: August 2013

We study the spectrum structure of discrete second-order Neumann boundary value problems (NBVPs) with sign-changing weight. We apply the properties of characteristic determinant of the NBVPs to show that the spectrum consists of real and simple eigenvalues; the number of positive eigenvalues is equal to the number of positive elements in the weight function, and the number of negative eigenvalues is equal to the number of negative elements in the weight function. We also show that the eigenfunction corresponding to thejth positive/negative eigenvalue changes its sign exactlyj-1times.
Codetection ofTrichomonas vaginalisandCandida albicansby PCR in Urine Samples in a Low-Risk Population Attended in a Clinic First Level in Central Veracruz, Mexico
Authors: López-Monteon A. , Gómez-Figueroa F. S. , Ramos-Poceros G. , Guzmán-Gómez D. , Ramos-Ligonio A.
Published: August 2013

The aim of this study is to estimate the prevalence ofTrichomonas vaginalisandCandida albicansin low-risk patients treated at a first level clinic (primary health care represents the first level of contact of individuals, families, and the community with the system national health). Using a cross-sectional study in patients treated in clinical laboratory of the Sanitary District no. 7 of the city of Orizaba during the months June-July, 252 urine samples were collected for the identification ofT. vaginalisandC. albicansby PCR. Furthermore, we analyzed the sociodemographic characteristics of the studied population. We observed an overall prevalence of 23.41% (95% CI 22.10–24.72) forT. vaginalisand 38.88% (95% CI 37.73–40.03) forC. albicans. There was also presence of coinfection in 14.28% (95% CI 13.10–15.46), which was associated with the presence of pain. Most of the positive cases were observed in women house-maker (80%, 95% CI 50.36–48.98). The results of this study provide evidence that the majority of positive cases observed in the studied population are presented in an asymptomatic form and usually are not associated with any risk factor.
Obesity as a Major Risk Factor for Cancer
Authors: De Pergola Giovanni , Silvestris Franco
Published: August 2013

The number of cancer cases caused by being obese is estimated to be 20% with the increased risk of malignancies being influenced by diet, weight change, and body fat distribution together with physical activity. Reports from the International Agency for Research into Cancer and the World Cancer Research Fund (WCRF) have shown that the strongest evidence exists for an association of obesity with the following cancer types: endometrial, esophageal adenocarcinoma, colorectal, postmenopausal breast, prostate, and renal, whereas the less common malignancies are leukemia, non-Hodgkin’s lymphoma, multiple myeloma, malignant melanoma, and thyroid tumours. To be able to develop novel methods in prevention and treatment, we first must understand the underlying processes which link cancer to obesity. Four main systems have been identified as potential producers of cancer in obesity: insulin, insulin-like growth factor-I, sex steroids, and adipokines. Various novel candidate mechanisms have been proposed: chronic inflammation, oxidative stress, crosstalk between tumour cells and surrounding adipocytes, migrating adipose stromal cells, obesity-induced hypoxia, shared genetic susceptibility, and the functional defeat of immune function. Herein, we review the major pathogenic links between obesity and susceptibility to cancer.
Transcription Regulation of Plastid Genes Involved in Sulfate Transport in Viridiplantae
Authors: Lyubetsky Vassily A. , Seliverstov Alexander V. , Zverkov Oleg A.
Published: August 2013

This study considers transcription regulation of plastid genes involved in sulfate transport in the parasites of invertebrate (Helicosporidiumsp.) and other species of the Viridiplantae. A one-box conserved motif with the consensus TAAWATGATT is found near promoters upstream thecysTandcysAgenes in many species. In certain cases, the motif is repeated two or three times.