bluuebunny/crossref_metadata_2025 huggingface dataset:
A Method for the Electrophoretic Characterization of Sulfite Reductases in Crude Preparations from Sulfate-Reducing Bacteria Using Polyacrylamide Gels
Authors: Skyring G. W. , Trudinger P. A.
Published: December 2009

Sulfite reductases in crude extracts of sulfate-reducing bacteria were detected by a polyacrylamide gel disc electrophoretic technique in which the sites of sulfite reductase activity were identified by precipitating sulfide as black FeS. Black bands were coincident with brown bands in Desulfotomaculum nigrificans extracts and with green bands in Desulfovibrio gigas extracts. The results are discussed in relation to present knowledge on sulfite reduction in sulfate-reducing bacteria.
Regulation of Hemoglobin Synthesis in the Blood Islands of Chick Blastodiscs. Tentative Identification of the Stimulatory Transfer RNA as a Minor Alanine-Specific Species
Authors: Wainwright S. D. , Wainwright Lillian K. , Tsay H. M.
Published: December 2009

Transfer RNA, isolated from adult chicken liver and from the membranes associated with the 5- to 6-day embryo, stimulated hemoglobin formation by de-embryonated chick blastodiscs explanted at the 5-somite stage onto medium containing a high concentration of actinomycin D. Preparations acylated specifically with alanine retained this biological activity when oxidized with periodate. The activity of preparations charged with amino acid mixtures lacking alanine was destroyed by periodate treatment.A minor species, representing less than 1% of the total, was largely resolved from the bulk of the alanine-specific tRNAs of chick liver by serial chromatography on benzoylated DEAE-cellulose. The isolated fraction contained the component which stimulated hemoglobin formation by blastodiscs explanted onto medium containing a high concentration of actinomycin.
Regulation of Onset of Rapid Hemoglobin Formation in Chick Blastodisc Blood Islands at the Transcription and Translation Levels. A Quantitative Analysis of Effects of Actinomycin, Ethanol, and Heme Precursors
Authors: Wainwright S. D. , Wainwright Lillian K.
Published: December 2009

Amounts of hemoglobin formed by blastodiscs explanted for 24 h on minimal medium containing 2 μg/ml of actinomycin were independent of initial stage of development between the 2- and 6-somite stages. No additional hemoglobin was formed by 2- to 4-somite blastodiscs in response to further supplements of aminolevulinate. In contrast, levels of hemoglobin formed in the presence of actinomycin by both younger and older blastodiscs were dependent on initial stage of development, and also were enhanced by aminolevulinate. Protoporphyrin both stimulated formation of hemoglobin on minimal medium to levels comparable with those formed on egg homogenate medium, and prevented inhibition by actinomycin of the synthesis of macromolecules. Ethanol in concentrations up to 1% had no effect on levels of hemoglobin formed or incorporation of precursors into macromolecules.On egg homogenate medium low concentrations of ethanol markedly stimulated hemoglobin formation, probably in part through induced synthesis of aminolevulinate synthetase enzyme. High concentrations of ethanol also inhibited incorporation of leucine into polypeptide. Incorporation of uridine into polynucleotide was only partially inhibited on egg homogenate medium containing 2 μg/ml of actinomycin. Hemoglobin formation was markedly less inhibited than on minimal medium and was stimulated by both aminolevulinate and protoporphyrin.
Binding of Some Primary Aromatic Amines to Certain Rat Brain Particulate Fractions
Authors: Boulton Alan A. , Wu P. H. , Philips S.
Published: December 2009

The unsubstituted aromatic amines β-phenylethylamine and tryptamine, on addition to rat brain homogenates, were found to form relatively stable 'complexes' with certain particulate fractions. Similar particulate 'complexes' were found following intraventricular injections. As a result of this binding the recovery of small quantities of these amines added to brain homogenates was variable and low when compared to other tissue homogenates. Although p-tyramine formed similar 'complexes' both the strength and extent of the binding was much reduced. Subcellular fractionation revealed that β-phenylethylamine, tryptamine, and p-tyramine were associated with a myelin and synaptosomal fraction.
Effects of Aldosterone on Mitochondrial Enzyme(s) and Cytochromes of Rat Tissues
Authors: Liu D. K. , Liew C. C. , Gornall A. G.
Published: December 2009

The activities of the kidney mitochondrial enzymes citrate synthase, NAD–isocitrate dehydrogenase, and α-ketoglutarate dehydrogenase, and the levels of cytochromes a + a3 and b were decreased following adrenalectomy. These decreases in enzyme activity and cytochrome levels could be restored by the administration of 5 μg of aldosterone per 100 g body weight. The effects of adrenalectomy and aldosterone administration were not observed in mitochondria from rat heart or liver. It was also found that giving 250 μg of corticosterone per 100 g body weight to adrenalectomized animals did not restore kidney citrate synthase activity. Neither actinomycin D nor puromycin, when given to adrenalectomized rats prior to aldosterone administration, inhibited the stimulation of citrate synthase activity or the levels of cytochromes a + a3 and b. It is concluded that the effect of aldosterone on the oxidative enzyme system is not the result of its stimulation of transcription or translation mechanisms.
Stereochemical Studies of Acyclic Isoprenoid Compounds. III. The Stereochemistry of Naturally Occurring (Marine) 2,6,10,14-Tetramethylpentadecane
Authors: Cox R. E. , Maxwell J. R. , Ackman R. G. , Hooper S. N.
Published: December 2009

High resolution gas chromatographic analysis of natural 2,6,10,14-tetramethylpentadecane from shark lipids shows it to comprise only the 6(R),10(S)-meso-isomer. This was confirmed by gas chromatographic analysis of esters of the acidic products of dichromate oxidation. These data support the hypothesis that the alkane derives from zooplanktonic metabolism of phytol (trans-3,7(R),11 (R),15-tetramethylhexadec-2-en-1-ol).
Steady-State Kinetics of Enzyme Reactions in the Presence of Added Nucleophiles
Authors: Hinberg Irwin , Laidler Keith J.
Published: December 2009

Many enzyme-catalyzed reactions, such as hydrolyses, give rise to two products P1 and P2 which are formed in different reaction steps. The second product P2 is frequently formed by hydrolysis of an intermediate such as an acyl-enzyme or a phosphoryl-enzyme. An alternative nucleophile N introduced into the system forms an additional product P3. The present paper is concerned with the kinetics of formation of P1, P2, and P3 in the presence of added nucleophiles. A number of alternative mechanisms are considered, and equations are derived for the rates of formation of the three products, and the Michaelis constant, as functions of nucleophile concentration. Graphs are presented showing the variations of these parameters with the concentration of N, for a variety of special cases. Special attention is given to the possibility of specific binding sites for the water and the nucleophile molecules.The data for a number of enzyme systems are discussed with reference to the treatment. For reactions catalyzed by alkaline phosphatase it is concluded that only one mechanism (mechanism VI) is consistent with the results.
Isolation and Identification of Egg Yolk Cholesteryl Esters
Authors: Tattrie N. H.
Published: December 2009

Cholesteryl esters and cholesterol were isolated from egg yolk lipids by thin-layer chromatography. The cholesteryl esters and cholesterol contents of egg yolk lipids were 0.34% and 3.64%, respectively, as determined by gas–liquid chromatography. The fatty acid composition of the cholesteryl esters was 16:0, 24.7%; 16:1, 4.6%; 18:0, 6.8%; 18:1, 53.3%; and 18:2, 10.7%.
THE INHOMOGENEOUS QUANTUM INVARIANCE GROUP OF q-DEFORMED BOSON ALGEBRA
Authors: ALTINTAS AZMI ALI , ARIK METIN , ARIKAN ALI SERDAR
Published: December 2009

We investigate the inhomogeneous invariance group of the q-deformed boson algebra. We find the R-matrix which gives the noncommuting structure of the quantum group with RM1M2 = M2M1R relation.
A GEOMETRIC PARAMETRIZATION OF THE CABIBBO–KOBAYASHI–MASKAWA MATRIX AND THE JARLSKOG INVARIANT
Authors: FUJII KAZUYUKI
Published: December 2009

In this paper we give a geometric parametrization to the Cabibbo–Kobayashi–Maskawa (CKM) mixing matrix and the Jarlskog invariant, which is based on two flag manifolds SU(3)/U(1)2.

To treat a fourth generation of quarks on CP violation we generalize the parametrization to one based on two flag manifolds SU(4)/U(1)3.
PSEUDO-SYMMETRIC LORENTZIAN THREE-MANIFOLDS
Authors: CALVARUSO G. , DE LEO B.
Published: December 2009

We investigate pseudo-symmetric Lorentzian three-manifolds for the different possible Segre types of the Ricci operator. After determining all three-dimensional pseudo-symmetric Lorentzian algebraic curvature tensors, we classify pseudo-symmetric Lorentzian three-spaces which are either homogeneous, curvature homogeneous up to order 1 or curvature homogeneous, and we also provide some examples which are not curvature homogeneous.
ON LOCAL F-THEORY GEOMETRIES AND INTERSECTING D7-BRANES
Authors: LAAMARA RACHID AHL , BELHAJ ADIL , BOYA LUIS J. , SEGUI ANTONIO
Published: December 2009

We discuss local F-theory geometries and their gauge theory dualities in terms of intersecting D7-branes wrapped four-cycles in Type IIB superstring. The manifolds are built as elliptic K3 surface fibrations over intersecting F0 = CP1 × CP1 base geometry according to ADE Dynkin Diagrams. The base is obtained by blowing up the extended ADE hyper-Kähler singularities of eight-dimensional manifolds considered as sigma model target spaces with eight supercharges. The resulting gauge theory of such local F-theory models are given in terms of Type IIB D7-branes wrapped intersecting F0. The four-dimensional N = 1 anomaly cancelation requirement translates into a condition on the associated affine Lie algebras.
Thin layer porphyrinogen for alcohol-vapor optical sensors
Authors: Manera Maria G. , Valli Ludovico , Conoci Sabrina , Rella Roberto
Published: December 2009

Thin films of meso-octaethylporphyrinogen with different thickness were deposited on suitable substrates by Langmuir-Blodgett deposition technique in order to realize optical-sensitive active layers using Surface Plasmon Resonance (SPR) technique as transduction methodology. Analysis of the morphology of the sensing layers was performed by Atomic Force Microscopy. In particular, such coatings were tested for the detection of alcohol vapors such as ethanol, methanol and isopropanol. This resulted in a reversible shift in the resonance depth and angular position of the SPR curves, depending on the interactions between the sensing layers and the alcohol vapor molecules. Different sensitivity and rate of response for different alcohol molecules were found and analyzed. Measurements of the sensing response towards successive expositions of the sensing layers to methanol, ethanol and isopropanol vapors were performed in order to analyze the discrimination properties of the active layers towards the analytes.
Multi-transduction of molecular recognition events in metalloporphyrin layers
Authors: Di Natale Corrado , Paolesse Roberto , D'Amico Arnaldo , Lundström Ingemar , Lloyd-Spetz Anita
Published: December 2009

Besides the design and synthesis of appropriate molecular recognition systems, the development of chemical sensors requires a careful selection of the transducer to allow conversion of the chemical interaction into an exploitable electric signal. Metalloporphyrins, which are characterized by manifold of interactions of different strength and selectivity, provide a good example of the complexity of such an issue. In this paper, an example of the different ways to capture interactions occurring in a metalloporphyrin layer is presented. In particular, the properties of mass (quartz microbalance) and surface potential transducers (field effect transistor) are illustrated. Results suggest that field effect transistors are more suitable to preserve the interactions magnitude scale than to maintain the original selectivity of the molecular recognition system.
Optical oxygen sensor devices using metalloporphyrins
Authors: Amao Yutaka , Okura Ichiro
Published: December 2009

Oxygen-monitoring techniques are applied to various fields, such as chemicals, deep sea environment, fluid dynamics, clinical analysis and environmental monitoring. Recently, a variety of devices and sensors based on phosphorescence or photoexcited state quenching of porphyrin molecules have been developed to measure oxygen concentration on the solid surface. Many optical oxygen sensors are composed of porphyrins (platinum(II), palladium(II), zinc(II), metal-free, etc.) dispersed in oxygen-permeable polymer film or directly immobilized onto solid surface via chemical or physical adsorption. Oxygen-sensing systems are classified into four types: (1) phosphorescence intensity change, (2) phosphorescence lifetime change, (3) change of lifetime of photoexcited triplet state, and (4) intensity change of absorption of photoexcited triplet state. In this review, the properties of various optical oxygen-sensing devices using porphyrins and sensing system are introduced.
Corrole-based ion-selective electrodes
Authors: Lvova Larisa , Di Natale Corrado , D'Amico Arnaldo , Paolesse Roberto
Published: December 2009

Different corrole derivatives have been exploited as ionophores for the development of ion-selective electrodes (ISEs). The compounds used are free-base 5,10,15-triphenylcorrole, the corresponding Mn and Fe chloride complexes, the Cu complex of 5,10,15-tris(4-tert-butylphenyl)-corrole and the Fe chloride complex of 2,3,17,18-tetraethyl,7,8,12,13-tetramethylcorrole. Corroles have been dispersed in the polyvinyl chloride polymeric matrix and different plasticizers have been used for the preparation of selective membranes. The developed ISEs have been tested for the detection of model analytes and the working mechanism has been investigated in detail. In the case of free-base corrole, the results showed that it is difficult to obtain high selective ISEs, due to the macrocycle high sensitivity to the background solution pH. On the other hand, Mn derivative are shown to be highly selective for chloride ion detection, with performances superior to the corresponding Mn porphyrin-based ISEs. Finally both Cu and Fe derivatives are very promising ionophores for the detection of hydrophilic anions, such as carbonate and monohydrogen phosphate ion.
Liquid crystal porphyrins as chemically sensitive coating materials for chemical sensors
Authors: Ahsen Ali Şems , Segade Antoni , Velasco Dolores , Öztürk Zafer Ziya
Published: December 2009

Columnar liquid crystal porphyrin compounds have been deposited onto the gold pads of quartz crystal microbalances (QMBs). The sensitivities of the resulting sensors have been measured with respect to volatile organic compounds (VOCs) and have been found to be of interest for future applications. The results show a strong influence of the length of the side alkyl chains, furthermore the thermal history of the coated film also affects the measured properties. The partition coefficients of the coatings have been calculated from the sensor responses.
THE EFFECT OF TRANSVERSE SHEAR AND NORMAL DEFORMATIONS ON THE THERMOMECHANICAL BENDING OF FUNCTIONALLY GRADED SANDWICH PLATES
Authors: ZENKOUR ASHRAF M.
Published: December 2009

A thermomechanical bending analysis for a simply supported, rectangular, functionally graded material sandwich plate subjected to a transverse mechanical load and a through-the-thickness thermal load is presented using the refined sinusoidal shear deformation plate theory. The present shear deformation theory includes the effect of both shear and normal deformations and it is simplified by enforcing traction-free boundary conditions at the plate faces. Material properties and thermal expansion coefficient of the sandwich plate faces are assumed to be graded in the thickness direction according to a simple power-law distribution in terms of the volume fractions of the constituents. The core layer is still homogeneous and made of an isotropic material. The equilibrium equations of different sandwich plates are given based on various plate theories. A number of examples are solved to illustrate the numerical results concern thermo-mechanical bending response of functionally graded rectangular sandwich plates. The influences played by transversal shear and normal deformations, plate aspect ratio, side-to-thickness ratio, volume fraction distributions, and thermal and mechanical loads are investigated.
EXPONENTIAL LENGTH OF CERTAIN SEQUENCES OF SUBSETS
Authors: Kalorkoti K.
Published: December 2009

We consider sequences of subsets of a finite base set satisfying a condition that arises out of an application and show that there are such sequences whose length is exponential in the cardinality of the base set. We also provide an upper bound (which is much larger than the lower bound).
A DECOMPOSITION OF A QUASI-OSCILLATOR
Authors: Yu. Shahverdian A.
Published: December 2009

A decomposition of a simplest mechanical system – a q-oscillator, is considered. A q-oscillator (quasi-oscillator) is defined as a system consisting of a particle moving on a linear segment with a constant speed and reflecting from the segment's end-points. A theorem, stating that a discrete-time version of q-oscillator can be decomposed into a countable set of discrete-time rotators (a rotator consists of a particle rotating on a circle with a constant angular rate) as well as a metrical theorem, concerning the rate of such decomposition, are proved. Some physics-related examples are discussed. A phase-shifting perturbed rotator and a number-theoretical matrix system modelling the quantum oscillator, are presented.
DERIVED SERIES OF THE FINITARY AUTOMORPHISMS GROUP OF THE 4-ADIC ROOTED TREE
Authors: Szaszkowski Zb.
Published: December 2009

The derived series of the finitary automorphisms group of the 4-adic rooted tree are described in terms of recurrent presentations.
ISOMORPHISMS OF TRANSFORMATION SEMIGROUPS ASSOCIATED WITH SIMPLE DIGRAPHS
Authors: Yang Xiuliang , Yang Haobo
Published: December 2009

For each simple digraph D, we introduce its associated semigroup S(D) and its widened digraph W(D). We show that, for any two finite simple digraphs D1 and D2, S(D1) and S(D2) are isomorphic as semigroups if and only if W(D1) and W(D2) are isomorphic as digraphs.
Regulation of vascular smooth muscle cell calcification by extracellular pyrophosphate homeostasis: synergistic modulation by cyclic AMP and hyperphosphatemia
Authors: Prosdocimo Domenick A. , Wyler Steven C. , Romani Andrea M. , O'Neill W. Charles , Dubyak George R.
Published: December 2009

Vascular calcification is a multifaceted process involving gain of calcification inducers and loss of calcification inhibitors. One such inhibitor is inorganic pyrophosphate (PPi), and regulated generation and homeostasis of extracellular PPi is a critical determinant of soft-tissue mineralization. We recently described an autocrine mechanism of extracellular PPi generation in cultured rat aortic vascular smooth muscle cells (VSMC) that involves both ATP release coupled to the ectophosphodiesterase/pyrophosphatase ENPP1 and efflux of intracellular PPi mediated or regulated by the plasma membrane protein ANK. We now report that increased cAMP signaling and elevated extracellular inorganic phosphate (Pi) act synergistically to induce calcification of these VSMC that is correlated with progressive reduction in ability to accumulate extracellular PPi. Attenuated PPi accumulation was mediated in part by cAMP-dependent decrease in ANK expression coordinated with cAMP-dependent increase in expression of TNAP, the tissue nonselective alkaline phosphatase that degrades PPi. Stimulation of cAMP signaling did not alter ATP release or ENPP1 expression, and the cAMP-induced changes in ANK and TNAP expression were not sufficient to induce calcification. Elevated extracellular Pi alone elicited only minor calcification and no significant changes in ANK, TNAP, or ENPP1. In contrast, combined with a cAMP stimulus, elevated Pi induced decreases in the ATP release pathway(s) that supports ENPP1 activity; this resulted in markedly reduced rates of PPi accumulation that facilitated robust calcification. Calcified VSMC were characterized by maintained expression of multiple SMC differentiation marker proteins including smooth muscle (SM) α-actin, SM22α, and calponin. Notably, addition of exogenous ATP (or PPi per se) rescued cAMP + phosphate-treated VSMC cultures from progression to the calcified state. These observations support a model in which extracellular PPi generation mediated by both ANK- and ATP release-dependent mechanisms serves as a critical regulator of VSMC calcification.
Refractory blood pressure in female SHR to increased oxidative stress is not mediated by NO or by upregulation of renal antioxidant enzymes
Authors: Lopez-Ruiz Arnaldo F. , Iliescu Radu , Reckelhoff Jane F.
Published: December 2009

There is a sex difference in the blood pressure (BP) responses to prooxidants and antioxidants in the spontaneously hypertensive rat (SHR). In contrast to males, BP in female SHR does not decrease in response to antioxidants, such as tempol or apocynin, or increase in response to the prooxidant, molsidomine. Molsidomine decreases BP and increases expression of antioxidants in male Wistar-Kyoto rats (WKY), but not male SHR. The present study tested the hypothesis that the mechanism responsible for the lack of a pressor response to molsidomine in females is due to higher endogenous nitric oxide (NO) or to compensatory upregulation of renal antioxidant enzymes. Female SHR were treated with molsidomine in the presence or absence of nitro-l-arginine methyl ester (l-NAME) for 2 wk. Molsidomine increased nitrate/nitrite (NOx) and F2-isoprostane (F2-IsoP) excretion, whereas l-NAME reduced NOxbut increased F-Isop. Molsidomine and l-NAME together further reduced NOxand increased F2-IsoP. Molsidomine alone had no effect on BP; l-NAME alone increased BP. The combination of molsidomine and l-NAME did not increase BP above l-NAME alone levels. Whole body and renal oxidative stress increased, while renal cortical Cu,Zn-SOD expression was downregulated and catalase was upregulated by molsidomine; glutathione peroxidase expression was unaffected. These data support our previous studies suggesting that BP in female SHR is independent of either increases or decreases in oxidative stress. The mechanisms responsible for the sex difference in BP response to increase or decrease of oxidative stress are not due to increased NO in females or to compensatory upregulation of antioxidant enzymes in response to increases in oxidants.
Asymmetric dimethylarginine in angiotensin II-induced hypertension
Authors: Sasser Jennifer M. , Moningka Natasha C. , Cunningham Mark W. , Croker Byron , Baylis Chris
Published: December 2009

Recent studies have shown that asymmetric dimethylarginine (ADMA), a nitric oxide synthase inhibitor, is increased in hypertension and chronic kidney disease. However, little is known about the effects of hypertension per se on ADMA metabolism. The purpose of this study was to test the hypothesis that ANG II-induced hypertension, in the absence of renal injury, is associated with increased oxidative stress and plasma and renal cortex ADMA levels in rats. Male Sprague-Dawley rats were treated with ANG II at 200 ng·kg−1·min−1 sc (by minipump) for 1 or 3 wk or at 400 ng·kg−1·min−1 for 6 wk. Mean arterial pressure was increased after 3 and 6 wk of ANG II; however, renal injury (proteinuria, glomerular sclerosis, and interstitial fibrosis) was only evident after 6 wk of treatment. Plasma thiobarbituric acid reactive substances concentration and renal cortex p22phox protein abundance were increased early (1 and 3 wk), but urinary excretion of isoprostane and H2O2 was only increased after 6 wk of ANG II. An increased in plasma ADMA after 6 wk of ANG II was associated with increased lung protein arginine methyltransferase-1 abundance and decreased renal cortex dimethylarginine dimethylaminohydrolase activity. No changes in renal cortex ADMA were observed. ANG II hypertension in the absence of renal injury is not associated with increased ADMA; however, when the severity and duration of the treatment were increased, plasma ADMA increased. These data suggest that elevated blood pressure alone, for up to 3 wk, in the absence of renal injury does not play an important role in the regulation of ADMA. However, the presence of renal injury and sustained hypertension for 6 wk increases ADMA levels and contributes to nitric oxide deficiency and cardiovascular disease.
HIVAN phenotype: consequence of epithelial mesenchymal transdifferentiation
Authors: Yadav Anju , Vallabu Sridevi , Kumar Dileep , Ding Guohua , Charney Douglas N. , Chander Praveen N. , Singhal Pravin C.
Published: December 2009

Human immunodeficiency virus (HIV)-1-associated nephropathy (HIVAN) is characterized by proliferation of glomerular and tubular epithelial cells. We studied the role of epithelial mesenchymal transdifferentiation (EMT) in the development of HIVAN phenotype. Renal cortical sections from six FVB/N (control) and six Tg26 (HIVAN) mice were immunolabeled for PCNA, α-smooth muscle actin (α-SMA), fibroblast-specific protein-1 (FSP1), CD3, and F4/80. Since periglomerular cells (PGCs) and peritubular cells (PTCs) did not show any labeling for CD3 and F4/80 but showed labeling for α-SMA or FSP1, it appears that these were myofibroblasts that migrated from either glomerular or tubular sites, respectively. Occurrence of EMT was also supported by diminished expression of E-cadherin by renal epithelial cells in Tg26 mice. Interestingly, Tg26 mice also showed enhanced renal tissue expression of ZEB2; henceforth, it appears that transcription of molecules required for maintenance of de novo renal epithelial cell phenotype was suppressed. To evaluate the role of ANG II, Tg26 mice in groups of three were administered either normal saline or telmisartan (an AT1receptor blocker) for 2 wk, followed by evaluation for renal cell EMT. Renal cortical section of Tg26 mice showed a sevenfold increase ( P < 0.001) in parietal epithelial cell (PEC)-PGC and a threefold increase ( P < 0.01) in tubular cell (TC)-PTC proliferation (PCNA-positive cells). Similarly, both PECs-PGCs and TCs-PTCs in Tg26 mice showed enhanced expression of α-SMA and FSP1. Both PECs and podocytes contributed to the glomerular proliferative phenotype, but the contribution of PECs was much greater. Telmisartan-receiving Tg26 mice (TRM) showed attenuated number of proliferating PECs-PGCs and TCs-PTCs compared with saline-receiving Tg26 mice (SRM). Similarly, TRM showed diminished expression of α-SMA and FSP1 by both PECs-PGCs and TCs-PTCs compared with SRM. We conclude that EMT contributes to the manifestation of the proliferative phenotype in HIVAN mice.
Troglitazone ameliorates high glucose-induced EMT and dysfunction of SGLTs through PI3K/Akt, GSK-3β, Snail1, and β-catenin in renal proximal tubule cells
Authors: Lee Yu Jin , Han Ho Jae
Published: December 2009

Peroxisome proliferator-activated receptor-γ (PPARγ) agonists ameliorate renal fibrotic lesions in diabetic nephropathy. However, the effects of the agonists on the epithelial-mesenchymal transition (EMT) linked to membrane transport dysfunction are unknown. The present study aimed to verify the effects of the PPARγ agonist troglitazone on high glucose (HG)-induced EMT in primary cultured renal proximal tubular epithelial cells (PTCs). HG (25 mM) as well as hydrogen peroxide (H2O2) and transforming growth factor-β1 (TGF-β1) decreased expression of epithelial cell marker E-cadherin and increased the expression of the mesenchymal markers vimentin and α-smooth muscle actin (α-SMA). HG, H2O2, and TGF-β1 decreased Na+/H+exchangers (NHEs) or Na+-glucose cotransporters (SGLTs) and glucose uptake, showing membrane transport dysfunction. HG stimulated the production of cellular reactive oxygen species (ROS), and antioxidants blocked the HG-induced increase in phosphatidylinositol 3-kinase (PI3K)/Akt activation. Antioxidants and inhibitors of PI3K/Akt reversed HG-induced EMT protein expression. Inhibition of PI3K/Akt also blocked HG-induced glycogen synthase kinase-3β (GSK-3β) phosphorylation. HG and lithium chloride (GSK-3β inhibitor) blocked Snail1 and β-catenin activation. Moreover, transfection with Snail1 or β-catenin small interfering RNA (siRNA) reversed HG-induced EMT protein expression. Importantly, HG decreased PPARγ activation and troglitazone reversed HG-induced expression of PI3K/Akt, GSK-3β, Snail1, and β-catenin as well as EMT proteins. Finally, inhibitors of PI3K/Akt, Snail1/β-catenin siRNA, and troglitazone blocking the HG-induced EMT restored glucose uptake in PTCs. In conclusion, HG induces EMT through ROS, PI3K/Akt, GSK-3β, Snail, and β-catenin. Subsequently, HG-induced EMT may result in SGLT dysfunction that is restored by the PPARγ agonist troglitazone in primary cultured PTCs.
Disparate effects on renal and oxidative parameters following RAGE deletion, AGE accumulation inhibition, or dietary AGE control in experimental diabetic nephropathy
Authors: Tan Adeline L. Y. , Sourris Karly C. , Harcourt Brooke E. , Thallas-Bonke Vicki , Penfold Sally , Andrikopoulos Sofianos , Thomas Merlin C. , O'Brien Richard C. , Bierhaus Angelika , Cooper Mark E. , Forbes Josephine M. , Coughlan Melinda T.
Published: December 2009

Advanced glycation end products (AGEs) and the receptor for AGEs (RAGE) generate ROS, and therefore this study evaluated the effects of RAGE deletion, decreasing AGE accumulation, or lowering dietary AGE content on oxidative parameters in diabetic nephropathy (DN). Control and diabetic male wild-type and RAGE-deficient (RAGE−/−) mice were fed high- or low-AGE diets, with two groups given the inhibitor of AGE accumulation, alagebrium chloride, and followed for 24 wk. Diabetic RAGE−/−mice were protected against albuminuria, hyperfiltration, glomerulosclerosis, decreased renal mitochondrial ATP production, and excess generation of both mitochondrial and cytosolic superoxide. Whereas glomerulosclerosis, tubulointerstitial expansion, and hyperfiltration were improved in diabetic mice treated with alagebrium, there was no effect on urinary albumin excretion. Both diabetic RAGE−/−and alagebrium-treated mice had an attenuation of renal RAGE expression and decreased renal and urinary AGE (carboxymethyllysine) levels. Low-AGE diets did not confer renoprotection, lower the AGE burden or renal RAGE expression, or improve cytosolic or mitochondrial superoxide generation. Renal uncoupling protein-2 gene expression and mitochondrial membrane potential were attenuated by all therapeutic interventions in diabetic mice. In the present study, diverse approaches to block the AGE-RAGE axis had disparate effects on DN, which has potential clinical implications for the way this axis should be targeted in humans.
Vestibuloocular Reflex Adaptation Investigated With Chronic Motion-Modulated Electrical Stimulation of Semicircular Canal Afferents
Authors: Lewis Richard F. , Haburcakova Csilla , Gong Wangsong , Makary Chadi , Merfeld Daniel M.
Published: December 2009

To investigate vestibuloocular reflex (VOR) adaptation produced by changes in peripheral vestibular afference, we developed and tested a vestibular “prosthesis” that senses yaw-axis angular head velocity and uses this information to modulate the rate of electrical pulses applied to the lateral canal ampullary nerve. The ability of the brain to adapt the different components of the VOR (gain, phase, axis, and symmetry) during chronic prosthetic electrical stimulation was studied in two squirrel monkeys. After characterizing the normal yaw-axis VOR, electrodes were implanted in both lateral canals and the canals were plugged. The VOR in the canal-plugged/instrumented state was measured and then unilateral stimulation was applied by the prosthesis. The VOR was repeatedly measured over several months while the prosthetic stimulation was cycled between off, low-sensitivity, and high-sensitivity stimulation states. The VOR response initially demonstrated a low gain, abnormal rotational axis, and substantial asymmetry. During chronic stimulation the gain increased, the rotational axis improved, and the VOR became more symmetric. Gain changes were augmented by cycling the stimulation between the off and both low- and high-sensitivity states every few weeks. The VOR time constant remained low throughout the period of chronic stimulation. These results demonstrate that the brain can adaptively modify the gain, axis, and symmetry of the VOR when provided with chronic motion-modulated electrical stimulation by a canal prosthesis.
Tonic GABAA Receptor-Mediated Inhibition in the Rat Dorsal Motor Nucleus of the Vagus
Authors: Gao Hong , Smith Bret N.
Published: December 2009

Type A γ-aminobutyric acid (GABAA) receptors expressed in the dorsal motor nucleus of vagus (DMV) critically regulate the activity of vagal motor neurons and, by inference, the gastrointestinal (GI) tract. Two types of GABAA receptor-mediated inhibition have been identified in the brain, represented by phasic ( Iphasic) and tonic ( Itonic) inhibitory currents. The hypothesis that Itonic regulates neuron activity was tested in the DMV using whole cell patch-clamp recordings in transverse brain stem slices from rats. An Itonic was present in a subset of DMV neurons, which was determined to be mediated by different receptors than those mediating fast, synaptic currents. Preapplication of tetrodotoxin significantly decreased the resting Itonic amplitude in DMV neurons, suggesting that most of the current was due to action potential (AP)–dependent GABA release. Blocking GABA transport enhanced Itonic and multiple GABA transporters cooperated to regulate Itonic. The Itonic was composed of both a gabazine-insensitive component that was nearly saturated under basal conditions and a gabazine-sensitive component that was activated when extracellular GABA concentration was elevated. Perfusion of THIP (10 μM) significantly increased Itonic amplitude without increasing Iphasic amplitude. The Itonic played a major role in determining the overall excitability of DMV neurons by contributing to resting membrane potential and AP frequency. Our results indicate that Itonic contributes to DMV neuron membrane potential and activity and is thus an important regulator of vagally mediated GI function.
Acute Oligohydramnios: Antenatal Expression of VURD Syndrome?
Authors: Camanni D. , Zaccara A. , Capitanucci M.L. , Brizzi C. , Mobili L. , Giorlandino C. , Mosiello G. , De Gennaro M.
Published: December 2009

Objective: Oligohydramnios (OA) is nowadays regarded as one of the best markers of renal function (RF) impairment in bladder outlet obstruction (BOO) detected in utero. As such, its onset is usually early and progressive because of decline in fetal urine production. A series of acute OA complicating pregnancies with BOO has never been reported. Methods: Over a 7-year period, 5 fetuses with in utero suspicion of BOO exhibited an abrupt decrease of amniotic fluid after the 30th week of gestation. Results: All fetuses were delivered by cesarean section: diagnosis was posterior urethral valves in 3 cases, urethral atresia in 1, and prune-belly syndrome in 1. Urologic work-up demonstrated a unilateral vesicoureteral reflux dysplasia (VURD syndrome) in all 5 fetuses. RF at 1 year was normal in 4 fetuses and impaired in 1. Conclusions: Besides obstetrical reasons, OA may also have acute onset occurring in the presence of anomalies of the urinary tract; although diagnosis is almost always BOO, functional and anatomical characteristics of the urinary tract are those of VURD syndrome with a non-functioning, refluxing renal unit. The associated acute OA/VURD syndrome may represent a milder expression of a pop-off mechanism advocated in this syndrome with a more favorable prognosis than progressive OA detected early in pregnancy.
Three-Dimensional Computed Tomography Imaging of the Eustachian Tube Lumen in Patients with Patulous Eustachian Tube
Authors: Kikuchi Toshiaki , Oshima Takeshi , Hori Yoko , Kawase Tetsuaki , Kobayashi Toshimitsu
Published: December 2009

Background: The eustachian tube (ET) has a complicated anatomy, which is related to middle ear pathology. The anatomy of the ET has been well investigated in cadavers, but may not accurately reflect that in living subjects. Three-dimensional (3D) computed tomography (CT) was used to examine the ET in patients with patulous ET. Method: The subjects were 35 patients (17 males, aged 59 ± 16 years, and 18 females, aged 44 ± 15 years) with patulous ET which could be continuously traced from the pharyngeal orifice to the tympanic orifice (53 ears). CT was performed in the sitting position at rest, followed by 3D reconstruction. The course of the ET from the middle ear to the pharynx was visualized in 3D surface images. Morphological measurements of the curvature angle (angle C) and the inclination angle (angle I) were determined from 3D coordinates on the CT images. Results: The full length of the ET could be visualized in most patients suffering from patulous ET in the sitting position. Angle C was 21.7 ± 5.8° in the patients aged <40 years (n = 20), which is significantly larger than 16.7 ± 6.8° in the patients aged >59 years (n = 18; Student’s t test, p < 0.05). Angle I was 26.5 ± 4.2° in the patients aged <40 years (n = 20), also significantly larger than 21.6 ± 5.8° in the patients aged >59 years (n = 18; Student’s t test, p < 0.05). Conclusion: CT in the sitting position is a potential diagnostic tool of the ET and middle ear pathology.
Role of Gender in the Associations of Microalbuminuria with Inflammatory Markers in Hypertensive Subjects: A Cross-Sectional Study
Authors: Shantha Ghanshyam Palamaner Subash , Kumar Anita A. , Bharadhi Murali Krishna , Arthur Preetam
Published: December 2009

Background: Though the association between microalbuminuria (MA) and inflammatory markers has been studied, the possible gender differences in these associations have not yet been analyzed. Our study aims to analyze the role of gender in the associations of MA and inflammatory markers. Methods: 1,060 hypertensive patients were assessed for MA (albumin-creatinine ratio), plasma levels of HsCRP (high-sensitivity C-reactive protein), IL-18, and sCD40L (soluble CD40 ligand). Patients with diabetes mellitus, metabolic syndrome and overt nephropathy were excluded. Results: Mean age was 46 ± 9.6 years, with 560 males and 500 females. The prevalence of MA was 35.6% (n = 378). MA was associated with HsCRP (OR: 2.13, CI: 1.155–3.168, p = 0.001) and sCD40L (OR: 2.35, CI: 1.014–3.912, p = 0.013) in the premenopausal females, whereas in males (OR: 1.83, CI: 1.037–3.920, p = 0.023) and postmenopausal females (OR: 2.31, CI: 1.688–3.274, p = 0.031) MA was associated only with HsCRP and not with sCD40L or IL-18. Conclusions: Association between MA and HsCRP is consistent in all hypertensive patients. However, MA is associated with sCD40L only in premenopausal females and not in males and postmenopausal females.
Immunolocalization and mRNA Expression of Bone Morphogenetic Protein-6 in Human Clear Cell Renal Carcinoma
Authors: Basic-Jukic Nikolina , Radic-Antolic Margareta , Hudolin Tvrtko , Coric Marijana , Zadro Renata , Pasini Josip , Kastelan Zeljko , Kes Petar
Published: December 2009

Bone morphogenetic proteins (BMPs) are members of the transforming growth factor-β superfamily of proteins. Dysregulation of BMP signaling has been suggested in the carcinogenesis of different organs. We determined BMP-6 mRNA and protein expression in localized human clear cell renal carcinoma (CCRC), obtained from 20 patients who underwent nephrectomy, by the real-time polymerase chain reaction and immunohistochemistry. 15/20 patients exhibited higher BMP-6 mRNA expression in malignant than in healthy renal tissue relative to the PBGD expression (p < 0.05). Immunostaining intensity for BMP-6 in healthy renal tissue ranged from 0 to 2 (average 0.9), as well as in renal clear cell carcinoma (average 1.1). Seven of 20 (35%) healthy tissue samples failed to stain with BMP-6 antibody, compared to 2/20 (10%) tumor samples (p < 0.05). BMP-6 immunostaining was positive in 18/20 CCRC samples. Staining was localized in the cytoplasm and/or membrane of malignant cells. Malignant tissue had significantly higher BMP-6 mRNA expression than healthy tissue. There was no significant correlation between BMP-6 mRNA and protein expression with disease presentation, disease progression and patients’ characteristics. Long-term follow-up of our patients is needed to determine the possible role of increased expression of BMP-6 in CCRC.
N-Acetylcysteine Amide Protects Renal Proximal Tubular Epithelial Cells against Iohexol-Induced Apoptosis by Blocking p38 MAPK and iNOS Signaling
Authors: Gong Xuezhong , Celsi Gianni , Carlsson Katarina , Norgren Svante , Chen Ming
Published: December 2009

Background: The pathogenesis of contrast-induced nephropathy (CIN) is still poorly understood and apoptosis via oxidative stress has been proposed as one possible mechanism. We therefore studied the apoptotic signaling mechanism in CIN and also tested whether the new antioxidant N-acetylcysteine amide (NACA) could prevent CIN. Methods: LLC-PK1 cells were exposed to a widely used contrast agent, iohexol (IH). Cytotoxicity was assessed with morphology and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Cell death was analyzed by the DNA content analysis and PARP cleavage. Protein expression was assessed with Western blotting. Results: We observed cell death with apoptotic features in a dose- and time-dependent manner. Initiation of IH-induced apoptosis was mediated by upregulation of Bax and downregulation of Bcl-2 and Mcl-1, which was preceded by p38 MAPK activation and iNOS induction. Inhibitors of p38 MAPK and iNOS partially abolished IH-induced apoptosis. Furthermore, we found pretreatment with NACA partially protected cells from IH-induced death by reverting the expression of Bcl-2, Mc1-1 and Bax expression through inhibition of p38 MAPK and iNOS pathway. Conclusions: This study demonstrates that apoptosis occurs during CIN. Apoptosis is associated with activations of p38 MAPK and iNOS. Pretreatment with the antioxidant NACA could prevent IH-induced cell death by blocking the p38 MAPK/iNOS signaling pathway.
Alveolar Cell Senescence Exacerbates Pulmonary Inflammation in Patients with Chronic Obstructive Pulmonary Disease
Authors: Tsuji Takao , Aoshiba Kazutetsu , Nagai Atsushi
Published: December 2009

Background: Alveolar cell senescence is accelerated in patients with chronic obstructive pulmonary disease (COPD). Objectives: We tested the hypothesis that alveolar cell senescence contributes to the chronic inflammation that affects the lungs of COPD patients. Methods: We exposed alveolar type II-like epithelial (A549) cells to a G-quadruplex-interacting telomerase inhibitor in vitro to induce cellular senescence and analyzed the production of proinflammatory cytokines and the activation of NF-ĸB. Human dermal microvascular endothelial cells (HDMECs) were serially passaged to induce replicative senescence. We also immunostained human lung tissue sections obtained from COPD patients, asymptomatic smokers and asymptomatic nonsmokers and examined correlations between type II cell senescence and inflammation. Results: Senescent A549 cells and HDMECs, whether stimulated with lipopolysaccharide or not, produced greater amounts of IL-6, IL-8 and TNF-α, which paralleled NF-ĸB activation, than did presenescent cells. There were positive correlations between the percentages of senescent type II cells that expressed p16INK4a and the percentages of type II cells that expressed phosphorylated NF-ĸB. The lung tissue of the COPD patients contained higher percentages of proinflammatory senescent type II cells that co-expressed p16INK4a and phosphorylated NF-ĸB than the tissue from asymptomatic smokers and asymptomatic nonsmokers. Higher percentages of p16INK4a-positive senescent type II cells than of p16INK4a-negative presenescent type II cells were positive for phosphorylated NF-ĸB. Conclusions: Senescence of alveolar epithelial cells is associated with functional alterations of the cells to a proinflammatory phenotype and may contribute to the pathogenesis of COPD.
An Improvement in Forecasting Rapid Intensification of Typhoon Sinlaku (2008) Using Clear-Sky Full Spatial Resolution Advanced IR Soundings
Authors: Liu Hui , Li Jun
Published: December 2009

Hyperspectral infrared (IR) sounders, such as the Atmospheric Infrared Sounder (AIRS) and the Infrared Atmospheric Sounding Interferometer (IASI), provide unprecedented global atmospheric temperature and moisture soundings with high vertical resolution and accuracy. In this paper, the authors investigate whether advanced IR soundings of water vapor and temperature observations can improve the analysis of a tropical cyclone vortex and the forecast of rapid intensification of a tropical cyclone. Both the IR water vapor and temperature soundings significantly improve the typhoon vortex in the analysis and the forecast of the rapid intensification of Typhoon Sinlaku (2008). The typhoon track forecast is also substantially improved when the full spatial resolution AIRS soundings are assimilated. This study demonstrates the potential important application of high spatial and hyperspectral IR soundings in forecasting tropical cyclones.
Exploration of Climate Data Using Interactive Visualization*
Authors: Ladstädter Florian , Steiner Andrea K. , Lackner Bettina C. , Pirscher Barbara , Kirchengast Gottfried , Kehrer Johannes , Hauser Helwig , Muigg Philipp , Doleisch Helmut
Published: December 2009

In atmospheric and climate research, the increasing amount of data available from climate models and observations provides new challenges for data analysis. The authors present interactive visual exploration as an innovative approach to handle large datasets. Visual exploration does not require any previous knowledge about the data, as is usually the case with classical statistics. It facilitates iterative and interactive browsing of the parameter space to quickly understand the data characteristics, to identify deficiencies, to easily focus on interesting features, and to come up with new hypotheses about the data. These properties extend the common statistical treatment of data, and provide a fundamentally different approach. The authors demonstrate the potential of this technology by exploring atmospheric climate data from different sources including reanalysis datasets, climate models, and radio occultation satellite data. Results are compared to those from classical statistics, revealing the complementary advantages of visual exploration. Combining both the analytical precision of classical statistics and the holistic power of interactive visual exploration, the usual workflow of studying climate data can be enhanced.
Permeability Predictions for Woven Fabric Preforms
Authors: Chen Zuo-Rong , Lin Ye  , Meng Lu
Published: December 2009

A model is proposed to predict woven fabric permeability. The dual-scale fabric preform is represented by a unit cell of heterogeneous porous medium consisting of equivalent intertow and intratow porous media. The Stokes equation is used to model the flow in the intertow region of the unit cell, and the permeability of the equivalent intertow porous medium is calculated by back substituting the resultant pressure and velocity fields into Darcy’s law. With knowledge of the permeabilities of the two equivalent porous phases, the permeability of the unit cell for the fabric preform can be easily determined by solving the Darcy flow in the equivalent heterogeneous porous medium. The effects of geometrical parameters on the permeability of plain-weave fabric preforms are investigated. It is shown that, as well as the fiber volume fraction; other geometrical parameters such as the gap between adjacent tows also play an important role in determining permeability. Permeability predictions for three plain-weave fabrics show satisfactory agreement with experimental data available in the literature.