bluuebunny/crossref_metadata_2025 huggingface dataset:
A Case for the Ancient Origin of Coronaviruses
Authors: Wertheim Joel O. , Chu Daniel K. W. , Peiris Joseph S. M. , Kosakovsky Pond Sergei L. , Poon Leo L. M.
Published: April 2013

Coronaviruses are found in a diverse array of bat and bird species, which are believed to act as natural hosts. Molecular clock dating analyses of coronaviruses suggest that the most recent common ancestor of these viruses existed around 10,000 years ago. This relatively young age is in sharp contrast to the ancient evolutionary history of their putative natural hosts, which began diversifying tens of millions of years ago. Here, we attempted to resolve this discrepancy by applying more realistic evolutionary models that have previously revealed the ancient evolutionary history of other RNA viruses. By explicitly modeling variation in the strength of natural selection over time and thereby improving the modeling of substitution saturation, we found that the time to the most recent ancestor common for all coronaviruses is likely far greater (millions of years) than the previously inferred range.
Canine Distemper Virus Associated with a Lethal Outbreak in Monkeys Can Readily Adapt To Use Human Receptors
Authors: Sakai Kouji , Yoshikawa Tomoki , Seki Fumio , Fukushi Shuetsu , Tahara Maino , Nagata Noriyo , Ami Yasushi , Mizutani Tetsuya , Kurane Ichiro , Yamaguchi Ryoji , Hasegawa Hideki , Saijo Masayuki , Komase Katsuhiro , Morikawa Shigeru , Takeda Makoto
Published: April 2013

A canine distemper virus (CDV) strain, CYN07-dV, associated with a lethal outbreak in monkeys, used human signaling lymphocyte activation molecule as a receptor only poorly but readily adapted to use it following a P541S substitution in the hemagglutinin protein. Since CYN07-dV had an intrinsic ability to use human nectin-4, the adapted virus became able to use both human immune and epithelial cell receptors, as well as monkey and canine ones, suggesting that CDV can potentially infect humans.
Sodium Taurocholate Cotransporting Polypeptide Mediates Woolly Monkey Hepatitis B Virus Infection of Tupaia Hepatocytes
Authors: Zhong Guocai , Yan Huan , Wang Haimin , He Wenhui , Jing Zhiyi , Qi Yonghe , Fu Liran , Gao Zhenchao , Huang Yi , Xu Guangwei , Feng Xiaofeng , Sui Jianhua , Li Wenhui
Published: April 2013

Primary
Tupaia
hepatocytes (PTHs) are susceptible to woolly monkey hepatitis B virus (WMHBV) infection, but the identity of the cellular receptor(s) mediating WMHBV infection of PTHs remains unclear. Recently, sodium taurocholate cotransporting polypeptide (NTCP) was identified as a functional receptor for human hepatitis B virus (HBV) infection of primary human and
Tupaia
hepatocytes. In this study, a synthetic pre-S1 peptide from WMHBV was found to bind specifically to cells expressing
Tupaia
NTCP (tsNTCP) and it efficiently blocked WMHBV entry into PTHs; silencing of tsNTCP in PTHs significantly inhibited WMHBV infection. Ectopic expression of tsNTCP rendered HepG2 cells susceptible to WMHBV infection. These data demonstrate that tsNTCP is a functional receptor for WMHBV infection of PTHs. The result also indicates that NTCP's orthologs likely act as a common cellular receptor for all known primate hepadnaviruses.
Geographic tongue and tenofovir
Authors: Ferreira Alexandre Oliveira , Marinho Rui Tato , Velosa José , Costa João Borges
Published: April 2013

A 55-year-old male patient with chronic hepatitis B was started on tenofovir. One month after initiating the new medication, he developed severe symptomatology with odynophagia and a very painful tongue. The physical examination reveals multiple erythematous patches on his tongue and a biopsy was performed. It allowed the diagnosis of benign migratory glossitis or geographic tongue. The patient was kept on tenofovir, but had to start topical corticoid therapy. Geographic tongue is a common condition that may be caused by drug idiosyncrasy, but has never before been associated to tenofovir. It is usually asymptomatic, but sometimes it causes severe symptoms, being an important impairment of quality of life.
Giant anterior chest wall basal cell carcinoma: a reconstructive challenge and review of the literature
Authors: Warbrick-Smith James , O'Neill Jennifer K , Wilson Paul
Published: April 2013

Giant basal cell carcinomas (GBCC) are rare, accounting for <1% of BCCs. Those occurring on the anterior chest wall are a very rare subset that brings particular reconstructive challenges. We describe a 75-year-old man whose 13.5 cm diameter ulcerating GBCC on his left anterior chest came to medical attention following a fall. The lesion was resected en-bloc with adjacent ribs, and reconstructed with an omental flap, superiorly pedicled vertical rectus abdominus myocutaneous (VRAM) flap and split skin grafting. While the myriad reasons for delayed presentation of giant cutaneous malignancies are well documented, the complex nature of reconstruction and requirement for an integrated multidisciplinary approach are less so. It is of importance to note that the cicatricial nature of these lesions may result in a much larger defect requiring reconstruction than appreciated prior to resection. Documented cases of anterior chest wall GBCC and the treatment strategies employed are reviewed.
Serum 25-hydroxyvitamin D3and the risk of pneumonia in an ageing general population
Authors: Aregbesola Alex , Voutilainen Sari , Nurmi Tarja , Virtanen Jyrki K , Ronkainen Kimmo , Tuomainen Tomi-Pekka
Published: April 2013

Background

Vitamin D has been suggested to have a role in infection defence and on the immune system. We therefore investigated the effect of serum 25-hydroxyvitamin D3(25(OH)D3) on the risk of incident hospitalised pneumonia in an ageing general population in eastern Finland.

Methods

The study population included 723 men and 698 women aged 53–73 years from the prospective population-based Kuopio Ischemic Heart Disease Risk Factor study who were free of pneumonia, other pulmonary diseases and cancer at baseline in 1998–2001. Incident pneumonia episodes leading to hospitalisation were collected by record linkage to the hospital discharge register. The serum vitamin D status was assayed as 25(OH)D3concentration. Cox proportional hazards regression models were used to analyse the effect of serum 25(OH)D3on the risk of incident pneumonia.

Results

The mean (SD) serum 25(OH)D3concentration of the study population was 43.5 (17.8) nmol/l. 73 subjects had at least one hospitalisation episode due to pneumonia during an average follow-up of 9.8 years. After multivariable adjustments, the subjects in the lowest serum 25(OH)D3tertile had a 2.6-fold (95% CI 1.4 to 5.0, p trend across tertiles=0.005) higher risk of developing pneumonia compared with the subjects in the highest tertile. This significant result remained even after adjustment for the determinants of serum 25-hydroxyvitamin D3.

Conclusions

These data suggest an inverse effect of serum 25(OH)D3concentration on the risk of incident pneumonia in the general ageing population.
The ‘scientific artworks’ of Doctor Paul Richer
Authors: Ruiz-Gómez Natasha
Published: April 2013

This article examines the little-known sculptures of pathology created by Doctor Paul Richer (1849–1933) in the 1890s for the so-called Musée Charcot at the Hôpital de la Salpêtrière in Paris. Under the direction of Doctor Jean-Martin Charcot (1825–1893), one of the founders of modern neurology, Richer was the head of the hospital's museum of pathological anatomy, as well as the Salpêtrière's resident artist. His ‘series of figural representations of the principal types of nervous pathology’ included busts of patients suffering from labio-glosso-laryngeal paralysis and myopathy, as well as sculptures depicting patients with Parkinson's disease and juvenile hypothyroidism. These patient portraits were seen as objective, while also paradoxically providing an alternative to mechanical media, such as the photograph and the cast, by permitting the doctor's intervention in not only controlling and animating the sitter, but also emphasising the patient's symptoms. This was a new kind of medical specimen: the ‘scientific artwork’, as they were called by a contemporary. This phrase, far from being an oxymoron, indicates the purposive collapse of the objective (‘scientific’) and subjective (‘artistic’) binary in Richer's sculptures of pathology. Through a detailed examination of three of Richer's works, this article problematises the categories traditionally used to describe, analyse and understand medical imagery and complicates our understanding of the relationship between science and art at the end of the nineteenth century.
Proximal myopathy: diagnostic approach and initial management
Authors: Suresh Ernest , Wimalaratna Sunil
Published: April 2013

Proximal myopathy presents as symmetrical weakness of proximal upper and/or lower limbs. There is a broad range of underlying causes including drugs, alcohol, thyroid disease, osteomalacia, idiopathic inflammatory myopathies (IIM), hereditary myopathies, malignancy, infections and sarcoidosis. Clinical assessment should aim to distinguish proximal myopathy from other conditions that can present similarly, identify patients who need prompt attention, like those with cardiac, respiratory or pharyngeal muscle involvement, and determine underlying cause of myopathy. Initial evaluation should include simple tests, like creatine kinase, thyroid function and (25)OH vitamin D levels, but further evaluation including neurophysiological studies, muscle imaging and muscle biopsy should be considered for patients in whom no toxic, metabolic or endocrine cause is found, and in those with clinical features suggestive of inflammatory or hereditary myopathy. Additionally, screening for malignancy and testing for anti-Jo1 antibody is indicated for selected patients with IIM. Management depends on underlying cause, and includes measures, such as removal of offending agent, correction of endocrine or metabolic problem, corticosteroids and immunosuppressive therapy for IIM, and physical therapy, rehabilitation and genetic counselling for muscular dystrophies.
Prediction of soil water retention properties using pore-size distribution and porosity
Authors: Beckett Christopher T.S. , Augarde Charles E.
Published: April 2013

Several models have been suggested to link a soil's pore-size distribution to its retention properties. This paper presents a method that builds on previous techniques by incorporating porosity and particles of different sizes, shapes, and separation distances to predict soil water retention properties. Mechanisms are suggested for the determination of both the main drying and wetting paths, which incorporate an adsorbed water phase and retention hysteresis. Predicted results are then compared with measured retention data to validate the model and to provide a foundation for discussing the validity and limitations of using pore-size distributions to predict retention properties.
First record ofPorolepis(Sarcopterygii; Porolepiformes) from eastern Gondwana
Authors: Johanson Zerina , Ahlberg Per Erik , Ritchie Alex
Published: April 2013

Porolepiformes (Sarcopterygii) are poorly represented in the Devonian of Australia and eastern Gondwana as a whole. New cosmine-covered lower jaws from the Mulga Downs Group, western New South Wales (?Pragian–Emsian or Eifelian), represent the first occurrence of Porolepis in Australia, a genus formerly known exclusively from the Northern Hemisphere. This material is assigned to the new species Porolepis foxi. The wide distribution of Porolepis, demonstrated by its occurrence in New South Wales, Europe, and Spitsbergen, contrasts with the generally high endemicity of the faunas in which it is present.
Ceratopsia increase: history and trends
Authors: Dodson Peter
Published: April 2013

The taxonomic history of the Ceratopsia began in 1876 with the description of Monoclonius crassus Cope followed in 1889 by Triceratops horridus Marsh. After a peak of discovery and description in the 1910s and 1920s resulting from the Canadian dinosaur rush in the province of Alberta and the Central Asiatic Expeditions to Mongolia of the American Museum of Natural History, the study of ceratopsians declined to a low level until the 1990s, when discoveries in China, Montana, Utah, Alberta, and elsewhere, abetted by increased biostratigraphic and phylogenetic precision, led to an unprecedented resurgence of activity. Even Richard C. Fox, along with colleagues from Peking University, joined in the activity, by naming Psittacosaurus lujiatunensis. To place the activity in historical perspective, half of all known ceratopsians have been described since 2003. Despite important finds of basal ceratopsians in China, Mongolia, and Korea, North America continues to dominate ceratopsian, especially ceratopsid, diversity.
Influence of the limit of detection on classification using otolith elemental signatures
Authors: Higgins Ruth M. , Danilowicz Bret S. , Brophy Deirdre , Geffen Audrey J. , McGowan Ted
Published: April 2013

Otolith elemental composition is a commonly used tool in the classification of fish stocks. Lower detection limits associated with trace element analysis techniques are the source of much debate among fisheries biologists. Using empirical data from Atlantic herring (Clupea harengus) from two separate origins in the British Isles, we addressed methods of treating data at or falling below detection limits and the implications of each treatment for discrimination and classification analysis. Estimating actual values of non-detected concentrations, through imputation, is now a plausible and simply applied strategy and should be considered as an alternative to constant replacement. We compare a robust regression approach to estimating values for non-detects alongside a variety of constant replacement methods. We also show the value of a highly censored variable in understanding population discrimination; despite 40% of readings for one element being non-detects, we found that its removal was detrimental to the discriminatory power of the analysis.
Endogenous hydrogen sulfide in perivascular adipose tissue: role in the regulation of vascular tone in physiology and pathology
Authors: Bełtowski Jerzy
Published: April 2013

Hydrogen sulfide (H2S) is synthesized from l-cysteine by cystathionine β-synthase (CBS) or cystathionine γ-lyase (CSE), and is enzymatically metabolized in mitochondria by sulfide:quinone oxidoreductase (SQR). Recent studies have indicated that H2S is synthesized by CSE in perivascular adipose tissue (PVAT), and is responsible for the anticontractile effect of PVAT on adjacent vessels. The lipophilic statin atorvastatin increases PVAT-derived H2S by suppressing its mitochondrial oxidation; the effect that results from statin-induced depletion of ubiquinone. Experimental obesity induced by a highly palatable diet has a time-dependent effect on H2S in PVAT. Adipose tissue hypoxia suppresses H2S oxidation and increases its level in short-term obesity not associated with insulin resistance. In contrast, in long-term obesity, insulin resistance and (or) hyperinsulinemia result in the down-regulation of CSE and H2S deficiency, which is corrected by treatment with the insulin sensitizer rosiglitazone. In addition, cannabinoid CB1 receptor agonist administered for 2 weeks increases H2S by impairing mitochondria biogenesis. This indicates that the rate of mitochondrial H2S oxidation plays an important role in the regulation of H2S level in PVAT. Up-regulation of H2S signaling in short-term obesity and (or) by elevated endocannabinoids may be a compensatory mechanism that maintains vascular tone, despite endothelial dysfunction.
Enigmatic teeth of small theropod dinosaurs from the Upper Cretaceous (Cenomanian–Turonian) of Uzbekistan
Authors: Sues Hans-Dieter , Averianov Alexander
Published: April 2013

Upper Cretaceous (Cenomanian–Turonian) formations in the Kyzylkum Desert of Uzbekistan, especially the Bissekty Formation at Dzharakuduk, have yielded a great diversity of continental vertebrates, including dinosaurs. Underwater screening of the sandy matrix has recovered many dinosaurian teeth. Here we describe and illustrate two types of enigmatic theropod teeth that are referable to Paronychodon and Richardoestesia, respectively. Both of these tooth taxa are well known from the Late Cretaceous of North America and possibly represent stages in the development of the teeth of various paravian theropods. Confirmation of this hypothesis awaits discovery of more complete jaws.
Taxonomic diversity, stratigraphic range, and exceptional preservation of Juro-Cretaceous salamanders from northern China
Authors: Gao Ke-Qin , Chen Jianye , Jia Jia
Published: April 2013

Since the late 1990s, eight localities in volcanic shale-rich lacustrine deposits of Middle Jurassic through Early Cretaceous age in northern China (western Liaoning Province, northern Hebei Province, and southern Inner Mongolia) have yielded thousands of exceptionally well-preserved salamander specimens. With 10 species published and several new taxa yet to be named and described, the fossil samples from northern China represent the most species-diverse, individually abundant, and exquisitely preserved salamander fossil assemblage known from the Mesozoic Era. The stratigraphic range of the fossil record covers a geologic time span of roughly 40–45 million years from the Middle Jurassic (Bathonian) through the Early Cretaceous (Aptian). In contrast to the well-known stem-group salamanders Karaurus and Kokartus from the Middle to Late Jurassic of Middle Asia, the Chinese record contains the earliest known crown-group salamanders, including Jurassic representatives of both Cryptobranchoidea and Salamandroidea. The Chinese Mesozoic record includes numerous examples of virtually complete larval, juvenile, young adult, and fully grown adult individuals that collectively provide key information on the life histories and developmental patterns of the earliest known crown-group salamanders. Many specimens show preservation of soft tissue structures, including body outline, eye, liver, and external gill filaments. This kind of soft tissue preservation is unusual for fossil salamanders, so the Chinese Mesozoic specimens are important for furnishing otherwise unavailable information on the life history, diversity, and ecological adaptations of early crown-group salamanders.
Cf.Wortmaniafrom the early Paleocene of Montana and an evaluation of the fossil record of the initial diversification of the Taeniodonta (Mammalia)
Authors: Clemens William A.
Published: April 2013

The Garbani Channel deposits, part of the Tullock Formation exposed in northeastern Montana, have yielded a large sample of vertebrates that probably lived during the Puercan 3 North American Land Mammal Age (NALMA). Four fossils in this sample — three isolated teeth and a medial phalanx — document the presence of a stylinodontid taeniodont, cf. Wortmania. Discovery of cf. Wortmania in the Tullock Formation extends the documented range of taeniodonts during Puercan 3 approximately 500 miles (800 km) northward from the San Juan Basin, New Mexico. Evaluation of the oldest records of taeniodonts, from the Lancian, Puercan, and Torrejonian NALMAs, highlights biases warranting future research. Recent phylogenetic analyses that resulted in numerous ghost lineages indicate that the available fossil record is far from complete. They open the possibility that the origin and initial radiation of taeniodonts occurred in areas yet to be sampled and their first occurrences might reflect immigration of invasive species. The available fossil record of taeniodonts is biased with significantly more abundant and complete specimens discovered in the San Juan Basin than at localities to the north. This bias is also apparent in the available samples of two other lineages of large Puercan mammals, the multituberculate Taeniolabis and the “triisodontid” Eoconodon. Where they occur, taeniodonts are relatively rare members of any local fauna. Is their rarity a product of an ecological bias or a reflection of decreasing population size related to increasing body size?
QUARKONIA IN THE QUARK GLUON PLASMA
Authors: MÓCSY ÁGNES , PETRECZKY PÉTER , STRICKLAND MICHAEL
Published: April 2013

In this paper, we review recent progress toward understanding the nature of quarkonia in the quark gluon plasma. We review the theory necessary to understand the melting of bound states due to color-screening, including lattice results for the heavy quark potential, lattice results on the correlation functions related to the relevant spectral functions, and the emergence of a complex-valued potential in high-temperature quantum chromodynamics. We close with a brief survey of phenomenological models of quarkonium suppression in relativistic heavy ion collisions.
ILLUMINATION INVARIANT FACE RECOGNITION IN QUATERNION DOMAIN
Authors: RIZO-RODRÍGUEZ DAYRON , MÉNDEZ-VAZQUEZ HEYDI , GARCÍA-REYES EDEL
Published: April 2013

The performance of face recognition systems tends to decrease when images are affected by illumination. Feature extraction is one of the main steps of a face recognition process, where it is possible to alleviate the illumination effects on face images. In order to increase the accuracy of recognition tasks, different methods for obtaining illumination invariant features have been developed. The aim of this work is to compare two different ways to represent face image descriptions in terms of their illumination invariant properties for face recognition. The first representation is constructed following the structure of complex numbers and the second one is based on quaternion numbers. Using four different face description approaches both representations are constructed, transformed into frequency domain and expressed in polar coordinates. The most illumination invariant component of each frequency domain representation is determined and used as the representative information of the face image. Verification and identification experiments are then performed in order to compare the discriminative power of the selected components. Representative component of the quaternion representation overcame the complex one.
PHOTOMETRIC NORMALIZATION FOR FACE RECOGNITION USING LOCAL DISCRETE COSINE TRANSFORM
Authors: MENDEZ-VÁZQUEZ HEYDI , KITTLER JOSEF , CHAN CHI HO , GARCÍA-REYES EDEL
Published: April 2013

Variations in illumination is one of major limiting factors of face recognition system performance. The effect of changes in the incident light on face images is analyzed, as well as its influence on the low frequency components of the image. Starting from this analysis, a new photometric normalization method for illumination invariant face recognition is presented. Low-frequency Discrete Cosine Transform coefficients in the logarithmic domain are used in a local way to reconstruct a slowly varying component of the face image which is caused by illumination. After smoothing, this component is subtracted from the original logarithmic image to compensate for illumination variations. Compared to other preprocessing algorithms, our method achieved a very good performance with a total error rate very similar to that produced by the best performing state-of-the-art algorithm. An in-depth analysis of the two preprocessing methods revealed notable differences in their behavior, which is exploited in a multiple classifier fusion framework to achieve further performance improvement. The superiority of the proposal is demonstrated in both face verification and identification experiments.
TIME REVERSAL SYMMETRY
Authors: HENLEY ERNEST M.
Published: April 2013

Time reversal independent of the CP symmetry is reviewed. Experimental tests of time reversal symmetry are given. Basic theories of time reversal invariance are provided.
IDENTIFICATION OF NONLINEAR CONTINUOUS DYNAMIC SYSTEMS WITH CLOSED CYCLE
Authors: SALUKVADZE MINDIA , SHANSHIASHVILI BESARION
Published: April 2013

Structural and parametric identification of nonlinear continuous dynamic systems with a closed cycle on a set of continuous block-oriented models with feedback is considered. The method of structural identification in the steady state based on the observation of the system's input and output variables at the input periodic influences is proposed. The solution of the parameter identification problems, which can be immediately connected with the structural identification problem, is carried out in the steady and transient states by the method of least squares. The structural and parametric identification algorithms are investigated by means of both theoretical analysis and computer modeling.
MESHFREE CELL-BASED SMOOTHED ALPHA RADIAL POINT INTERPOLATION METHOD (CS-α RPIM) FOR SOLID MECHANICS PROBLEMS
Authors: LIU G. R. , ZHANG G. Y. , ZONG Z. , LI M.
Published: April 2013

This paper presents a novel and effective cell-based smoothed alpha radial point interpolation method (CS-αRPIM) using αPIM shape functions for approximating displacement and cell-based smoothed strains for displacement gradient construction. Using a scaling factor α ∈ [0, 1], the αPIM shape functions are combinations of the condensed RPIM (RPIM-Cd) shape functions and the linear PIM shape functions, where the former often leads to a "softer" CS-RPIM model, and the latter a "stiffer" linear CS-RPIM model (which is as same as linear FEM), compared to the exact one. Through adjusting the value of α in our new CS-αRPIM, the stiffness of the model can be "designed" for desired purposes, such as for seeking nearly exact solutions in strain energy norm (or possibly other norms). A simple and practical procedure to search for such an α has also been presented. Some 2D and 3D numerical examples are studied to examine various properties of the present method in terms of accuracy, convergence and computational efficiency.
VENTILATION SYSTEM MODELING AND TURBULENCE MINIMIZATION
Authors: WHALLEY R. , ABDUL-AMEER A.
Published: April 2013

In this feasibility study, a large scale ventilation system comprising spatially dispersed enclosed volumes, fans, ducting and airways is considered. Analytical procedures enabling the construction of simple, compact models including the relatively pointwise and significantly distributed system elements are proposed. Modeling accuracy, with the incorporation of the entrance and exit impedances and the airway, continuous energy storage and dissipation effects are emphasized. Output flow maximization, under quiescent operating conditions is investigated and the optimum relationships between the airway characteristic impedance, entrance and exit resistances are established. The minimization of the vibration and turbulence arising from the continuous compression/expansion effects arising from the input–output volume airflow difference is achieved, whilst simultaneously maximizing the output volume airflow. Variations in the parameter values are employed to confirm the effectiveness of operating under optimum conditions, for ventilation system airways with various dimensions and characteristics.
Plasmalemmal sodium-calcium exchanger shapes the calcium and exocytotic signals of chromaffin cells at physiological temperature
Authors: Padín Juan-Fernando , Fernández-Morales José-Carlos , Olivares Román , Vestring Stefan , Arranz-Tagarro Juan-Alberto , Calvo-Gallardo Enrique , de Pascual Ricardo , Gandía Luís , García Antonio G.
Published: April 2013

The activity of the plasmalemmal Na+/Ca2+ exchanger (NCX) is highly sensitive to temperature. We took advantage of this fact to explore here the effects of the NCX blocker KB-R7943 (KBR) at 22 and 37°C on the kinetics of Ca2+ currents ( ICa), cytosolic Ca2+ ([Ca2+]c) transients, and catecholamine release from bovine chromaffin cells (BCCs) stimulated with high K+, caffeine, or histamine. At 22°C, the effects of KBR on those parameters were meager or nil. However, at 37°C whereby the NCX is moving Ca2+ at a rate fivefold higher than at 22°C, various of the effects of KBR were pronounced, namely: 1) no effects on ICa; 2) reduction of the [Ca2+]c transient amplitude and slowing down of its rate of clearance; 3) blockade of the K+-elicited quantal release of catecholamine; 4) blockade of burst catecholamine release elicited by K+; 5) no effect on catecholamine release elicited by short K+ pulses (1–2 s) and blockade of the responses produced by longer K+ pulses (3–5 s); and 6) potentiation of secretion elicited by histamine or caffeine. Furthermore, the more selective NCX blocker SEA0400 also potentiated the secretory responses to caffeine. The results suggest that at physiological temperature the NCX substantially contributes to shaping the kinetics of [Ca2+]c transients and the exocytotic responses elicited by Ca2+ entry through Ca2+ channels as well as by Ca2+ release from the endoplasmic reticulum.
Extracellular nucleotides inhibit oxalate transport by human intestinal Caco-2-BBe cells through PKC-δ activation
Authors: Amin Ruhul , Sharma Sapna , Ratakonda Sireesha , Hassan Hatim A.
Published: April 2013

Nephrolithiasis remains a major health problem in Western countries. Seventy to 80% of kidney stones are composed of calcium oxalate, and small changes in urinary oxalate affect risk of kidney stone formation. Intestinal oxalate secretion mediated by the anion exchanger SLC26A6 plays an essential role in preventing hyperoxaluria and calcium oxalate nephrolithiasis, indicating that understanding the mechanisms regulating intestinal oxalate transport is critical for management of hyperoxaluria. Purinergic signaling modulates several intestinal processes through pathways including PKC activation, which we previously found to inhibit Slc26a6 activity in mouse duodenal tissue. We therefore examined whether purinergic stimulation with ATP and UTP affects oxalate transport by human intestinal Caco-2-BBe (C2) cells. We measured [14C]oxalate uptake in the presence of an outward Cl− gradient as an assay of Cl−/oxalate exchange activity, ≥50% of which is mediated by SLC26A6. We found that ATP and UTP significantly inhibited oxalate transport by C2 cells, an effect blocked by the PKC inhibitor Gö-6983. Utilizing pharmacological agonists and antagonists, as well as PKC-δ knockdown studies, we observed that ATP inhibits oxalate transport through the P2Y2 receptor, PLC, and PKC-δ. Biotinylation studies showed that ATP inhibits oxalate transport by lowering SLC26A6 surface expression. These findings are of potential relevance to pathophysiology of inflammatory bowel disease-associated hyperoxaluria, where supraphysiological levels of ATP/UTP are expected and overexpression of the P2Y2 receptor has been reported. We conclude that ATP and UTP inhibit oxalate transport by lowering SLC26A6 surface expression in C2 cells through signaling pathways including the P2Y2 purinergic receptor, PLC, and PKC-δ.
Altered regulation of cytosolic Ca2+ concentration in dendritic cells from klotho hypomorphic mice
Authors: Shumilina Ekaterina , Nurbaeva Meerim K. , Yang Wenting , Schmid Evi , Szteyn Kalina , Russo Antonella , Heise Nicole , Leibrock Christina , Xuan Nguyen Thi , Faggio Caterina , Kuro-o Makoto , Lang Florian
Published: April 2013

The function of dendritic cells (DCs), antigen-presenting cells regulating naïve T-cells, is regulated by cytosolic Ca2+ concentration ([Ca2+]i). [Ca2+]i is increased by store-operated Ca2+ entry and decreased by K+-independent (NCX) and K+-dependent (NCKX) Na+/Ca2+ exchangers. NCKX exchangers are stimulated by immunosuppressive 1,25-dihydroxyvitamin D3 [1,25(OH)2D3], the biologically active form of vitamin D. Formation of 1,25(OH)2D3 is inhibited by the antiaging protein Klotho. Thus 1,25(OH)2D3 plasma levels are excessive in Klotho-deficient mice ( klotho hm). The present study explored whether Klotho deficiency modifies [Ca2+]i regulation in DCs. DCs were isolated from the bone marrow of klotho hm mice and wild-type mice ( klotho+/+) and cultured for 7–9 days with granulocyte-macrophage colony-stimulating factor. According to major histocompatibility complex II (MHC II) and CD86 expression, differentiation and lipopolysaccharide (LPS)-induced maturation were similar in klotho hm DCs and klotho+/+ DCs. However, NCKX1 membrane abundance and NCX/NCKX-activity were significantly enhanced in klotho hm DCs. The [Ca2+]i increase upon acute application of LPS (1 μg/ml) was significantly lower in klotho hm DCs than in klotho+/+ DCs, a difference reversed by the NCKX blocker 3′,4′-dichlorobenzamyl (DBZ; 10 μM). CCL21-dependent migration was significantly less in klotho hm DCs than in klotho+/+ DCs but could be restored by DBZ. NCKX activity was enhanced by pretreatment of klotho+/+ DC precursors with 1,25(OH)2D3 the first 2 days after isolation from bone marrow. Feeding klotho hm mice a vitamin D-deficient diet decreased NCKX activity, augmented LPS-induced increase of [Ca2+]i, and enhanced migration of klotho hm DCs, thus dissipating the differences between klotho hm DCs and klotho+/+ DCs. In conclusion, Klotho deficiency upregulates NCKX1 membrane abundance and Na+/Ca2+-exchange activity, thus blunting the increase of [Ca2+]i following LPS exposure and CCL21-mediated migration. The effects are in large part due to excessive 1,25(OH)2D3 formation.
A differential role of macrophage TRPM2 channels in Ca2+ signaling and cell death in early responses to H2O2
Authors: Zou Jie , Ainscough Justin F. , Yang Wei , Sedo Alicia , Yu Shu-Ping , Mei Zhu-Zhong , Sivaprasadarao Asipu , Beech David J. , Jiang Lin-Hua
Published: April 2013

Reactive oxygen species such as H2O2 elevates the cytosolic Ca2+ concentration ([Ca2+]c) and causes cell death via poly(ADPR) polymerase (PARP) activation, which also represents the primary mechanism by which H2O2 activate the transient receptor potential melastatin-related 2 (TRPM2) channel as a Ca2+-permeable channel present in the plasma membrane or an intracellular Ca2+-release channel. The present study aimed to define the contribution and mechanisms of the TRPM2 channels in macrophage cells in mediating Ca2+ signaling and cell death during initial response to H2O2, using mouse peritoneal macrophage, RAW264.7, and differentiated THP-1 cells. H2O2 evoked robust increases in the [Ca2+]c, and such Ca2+ responses were significantly greater at body temperature than room temperature. H2O2-induced Ca2+ responses were strongly inhibited by pretreatment with PJ-34, a PARP inhibitor, and largely prevented by removal of extracellular Ca2+. Furthermore, H2O2-induced increases in the [Ca2+]c were completely abolished in macrophage cells isolated from trpm2 −/− mice. H2O2 reduced macrophage cell viability in a duration- and concentration-dependent manner. H2O2-induced cell death was significantly attenuated by pretreatment with PJ-34 and TRPM2 channel deficiency but remained significant and persistent. Taken together, these results show that the TRPM2 channel in macrophage cells functions as a cell surface Ca2+-permeable channel that mediates Ca2+ influx and constitutes the principal Ca2+ signaling mechanism but has a limited, albeit significant, role in cell death during early exposure to H2O2.
Detection of endogenous substances with enzymatic microelectrode biosensors in the kidney
Authors: Palygin Oleg , Staruschenko Alexander
Published: April 2013

Direct real-time measurements of purinergic agents and reactive oxygen species concentrations have been of great value in understanding the functional roles of these substances in a number of diseases including chronic kidney disease and hypertension. The interstitial concentrations of these intermediate signaling molecules and dynamics of their release are important autocrine and paracrine factors in the kidney, which play a key role in the regulation of oxidative stress, inflammation, and kidney damage. Analysis of signaling mechanisms, especially in vivo and ex vivo, has been slowed by deficiencies of existing methods for direct measurements of the signaling molecules concentrations in whole organs and acute changes in response to endocrine factors. The multienzymatic microelectrode biosensors technique was originally developed and used for the detection of purines release in the brain and in present could be modified to identify the interplay between different substances that could be measured simultaneously in whole organs, such as the kidney. Adaptation of this method for renal and cardiovascular studies represents a unique powerful approach for real-time monitoring of substance level fluctuations in organs or tissues under normal or pathological conditions.
Rescue of dystrophic skeletal muscle by PGC-1α involves restored expression of dystrophin-associated protein complex components and satellite cell signaling
Authors: Hollinger Katrin , Gardan-Salmon Delphine , Santana Connie , Rice Drance , Snella Elizabeth , Selsby Joshua T.
Published: April 2013

Duchenne muscular dystrophy is typically diagnosed in the preschool years because of locomotor defects, indicative of muscle damage. Thus, effective therapies must be able to rescue muscle from further decline. We have established that peroxisome proliferator-activated receptor gamma coactivator 1-alpha ( Pgc-1α) gene transfer will prevent many aspects of dystrophic pathology, likely through upregulation of utrophin and increased oxidative capacity; however, the extent to which it will rescue muscle with disease manifestations has not been determined. Our hypothesis is that gene transfer of Pgc-1α into declining muscle will reduce muscle injury compared with control muscle. To test our hypothesis, adeno-associated virus 6 (AAV6) driving expression of Pgc-1α was injected into single hind limbs of 3-wk-old mdxmice, while the contralateral limb was given a sham injection. At 6 wk of age, treated solei had 37% less muscle injury compared with sham-treated muscles ( P < 0.05). Resistance to contraction-induced injury was improved 10% ( P < 0.05), likely driven by the five-fold ( P < 0.05) increase in utrophin protein expression and increase in dystrophin-associated complex members. Treated muscles were more resistant to fatigue, which was likely caused by the corresponding increase in oxidative markers. Pgc-1α overexpressing limbs also exhibited increased expression of genes related to muscle repair and autophagy. These data indicate that the Pgc-1α pathway remains a good therapeutic target, as it reduced muscle injury and improved function using a rescue paradigm. Further, these data also indicate that the beneficial effects of Pgc-1α gene transfer are more complex than increased utrophin expression and oxidative gene expression.
Alcohol exposure during late ovine gestation alters fetal liver iron homeostasis without apparent dysmorphology
Authors: Sozo Foula , Dick Anna M. , Bensley Jonathan G. , Kenna Kelly , Brien James F. , Harding Richard , De Matteo Robert
Published: April 2013

High levels of alcohol (ethanol) exposure during fetal life can affect liver development and can increase susceptibility to infection after birth. Our aim was to determine the effects of a moderate level of ethanol exposure in late gestation on the morphology, iron status, and inflammatory status of the ovine fetal liver. Pregnant ewes were chronically catheterized at 91 days of gestation (DG; term ∼145 DG) for daily intravenous infusion of ethanol (0.75 g/kg maternal body wt; n = 8) or saline ( n = 7) over 1 h from 95 to 133 DG. At necropsy (134 DG), fetal livers were collected for analysis. Liver weight, general liver morphology, hepatic cell proliferation and apoptosis, perivascular collagen deposition, and interleukin ( IL) -1β, IL-6, or IL-8 mRNA levels were not different between groups. However, ethanol exposure led to significant decreases in hepatic content of ferric iron and gene expression of the iron-regulating hormone hepcidin and tumor necrosis factor ( TNF) -α (all P < 0.05). In the placenta, there was no difference in transferrin receptor, divalent metal transporter 1, and ferritin mRNA levels; however, ferroportin mRNA levels were increased in ethanol-exposed animals ( P < 0.05), and ferroportin protein tended to be increased ( P = 0.054). Plasma iron concentration was not different between control and ethanol-exposed groups; control fetuses had significantly higher iron concentrations than their mothers, whereas maternal and fetal iron concentrations were similar in ethanol-exposed animals. We conclude that daily ethanol exposure during the third-trimester-equivalent in sheep does not alter fetal liver morphology; however, decreased fetal liver ferric iron content and altered hepcidin and ferroportin gene expression indicate that iron homeostasis is altered.
More than just a gut instinct–the potential interplay between a baby's nutrition, its gut microbiome, and the epigenome
Authors: Mischke Mona , Plösch Torsten
Published: April 2013

Substantial evidence links early postnatal nutrition to the development of obesity later in life. However, the molecular mechanisms of this connection must be further elucidated. Epigenetic mechanisms have been indicated to be involved in this process, referred to as metabolic programming. Therefore, we propose here that early postnatal nutrition (breast and formula feeding) epigenetically programs the developing organs via modulation of the gut microbiome and influences the body weight phenotype including the predisposition to obesity. Specifically, the early-age food patterns are known to determine the gross composition of the early gut microbiota. In turn, the microbiota produces large quantities of epigenetically active metabolites, such as folate and short chain fatty acids (butyrate and acetate). The spectrum of these produced metabolites depends on the composition of the gut microbiota. Hence, it is likely that changes in gut microbiota that result in altered metabolite composition might influence the epigenome of directly adjacent intestinal cells, as well as other major target cell populations, such as hepatocytes and adipocytes. Nuclear receptors and other transcription factors (the PPARs, LXR, RXR, and others) could be physiologically relevant targets of this metabolite-induced epigenetic regulation. Ultimately, transcriptional networks regulating energy balance could be manipulated. For these reasons, we postulate that early nutrition may influence the baby epigenome via microbial metabolites, which contributes to the observed relationship between early nutrition and adult obesity.
Real-time electrochemical detection of ATP and H2O2release in freshly isolated kidneys
Authors: Palygin Oleg , Levchenko Vladislav , Ilatovskaya Daria V. , Pavlov Tengis S. , Ryan Robert P. , Cowley Allen W. , Staruschenko Alexander
Published: April 2013

Extracellular nucleotides such as adenosine-5′-triphosphate (ATP) and reactive oxygen species are essential local signaling molecules in the kidney. However, measurements of changes in the interstitial concentrations of these substances in response to various stimuli remain hindered due to limitations of existing experimental techniques. The goal of this study was to develop a novel approach suitable for real-time measurements of ATP and H2O2levels in freshly isolated rat kidney. Rats were anesthetized and the kidneys were flushed to clear blood before isolation for consequent perfusion. The perfused kidneys were placed into a bath solution and dual simultaneous amperometric recordings were made with the enzymatic microelectrode biosensors detecting ATP and H2O2. It was found that basal levels of H2O2were increased in Dahl salt-sensitive (SS) rats fed a high-salt diet compared with SS and Sprague-Dawley rats fed a low-salt diet and that medulla contained higher levels of H2O2compared with cortex in both strains. In contrast, ATP levels did not change in SS rats when animals were fed a high-salt diet. Importantly, angiotensin II via AT1receptor induced rapid release of both ATP and H2O2and this effect was enhanced in SS rats. These results demonstrate that ATP and H2O2are critical in the development of salt-sensitive hypertension and that the current method represents a unique powerful approach for the real-time monitoring of the changes in endogenous substance levels in whole organs.
Expression and function of CCL2/CCR2 in rat micturition reflexes and somatic sensitivity with urinary bladder inflammation
Authors: Arms Lauren , Girard Beatrice M. , Malley Susan E. , Vizzard Margaret A.
Published: April 2013

Chemokines are proinflammatory mediators of the immune response, and there is growing evidence for chemokine/receptor signaling involvement in pronociception. Bladder pain syndrome (BPS)/interstitial cystitis (IC) is a chronic pain syndrome characterized by pain, pressure, or discomfort perceived to be bladder-related with at least one urinary symptom. We have explored the expression and functional roles of CCL2 (monocyte chemoattractant protein-1) and its high-affinity receptor, CCR2, in micturition reflex function and somatic sensitivity in rats with urinary bladder inflammation induced by cyclophosphamide (CYP) treatment of varying duration (4 h, 48 h, chronic). Real-time quantitative RT-PCR, ELISAs, and immunohistochemistry demonstrated significant ( P ≤ 0.01) increases in CCL2 and CCR2 expression in the urothelium and in Fast Blue-labeled bladder afferent neurons in lumbosacral dorsal root ganglia with CYP-induced cystitis. Intravesical infusion of RS504393 (5 μM), a specific CCR2 antagonist, reduced voiding frequency and increased bladder capacity and void volume in rats with CYP-induced cystitis (4 h), as determined with open outlet, conscious cystometry. In addition, CCR2 blockade, at the level of the urinary bladder, reduced referred somatic sensitivity of the hindpaw and pelvic region in rats with CYP treatment, as determined with von Frey filament testing. We provide evidence of functional roles for CCL2/CCR2 signaling at the level of the urinary bladder in reducing voiding frequency and somatic sensitivity following CYP-induced cystitis (4 h). These studies suggest that chemokines/receptors may be novel targets with therapeutic potential in the context of urinary bladder inflammation.
WNK4 inhibition of ENaC is independent of Nedd4-2-mediated ENaC ubiquitination
Authors: Yu Ling , Cai Hui , Yue Qian , Alli Abdel A. , Wang DeXuan , Al-Khalili Otor , Bao Hui-Fang , Eaton Douglas C.
Published: April 2013

A serine-threonine protein kinase, WNK4, reduces Na+reabsorption and K+secretion in the distal convoluted tubule by reducing trafficking of the thiazide-sensitive Na-Cl cotransporter to and enhancing renal outer medullary potassium channel retrieval from the apical membrane. Epithelial sodium channels (ENaC) in the distal nephron also play a role in regulating Na+reabsorption and are also regulated by WNK4, but the mechanism is unclear. In A6 distal nephron cells, transepithelial current measurement and single channel recording show that WNK4 inhibits ENaC activity. Analysis of the number of channel per patch shows that WNK4 reduces channel number but has no effect on channel open probability. Western blots of apical and total ENaC provide additional evidence that WNK4 reduces apical as well as total ENaC expression. WNK4 enhances ENaC internalization independent of Nedd4-2-mediated ENaC ubiquitination. WNK4 also reduced the amount of ENaC available for recycling but has no effect on the rate of transepithelial current increase to forskolin. In contrast, Nedd4-2 not only reduced ENaC in the recycling pool but also decreased the rate of increase of current after forskolin. WNK4 associates with wild-type as well as Liddle's mutated ENaC, and WNK4 reduces both wild-type and mutated ENaC expressed in HEK293 cells.