bluuebunny/crossref_metadata_2025 huggingface dataset:
The finite algebra for perception of rings in molecules
Authors: Kvasnička Vladimír , Bánki Július
Published: February 2011

The communication describes the finite algebra for perception of rings in molecules. It is demonstrated that for an arbitrary spaning tree we may construct the so-called restricted set of rings, which is composed of all possible (dependent and/or independent) rings that are classified by making use of some required constrains as chemically important. The method makes possible the formulation of efficient algorithms how to exhaustive perceive the rings in molecules.
Application of the Redlich-Kwong-Soave equation of state to the solubility of water in compressed gases
Authors: Novák Josef P. , Matouš Jaroslav , Pick Petr , Pick Jiří
Published: February 2011

Published data on the solubility of water in compressed gases were employed for calculating the interaction coefficients kij in the Redlich-Kwong-Soave equations of state for binary systems of water with argon, nitrogen, CO2, N2O, CH4, C2H6, or C2H4. With these coefficients, the estimate of the solubility of water in these gases has been improved by more than one order.
Optical activity of D-glyceraldehyde in aqueous solutions
Authors: Fedoroňko Michal
Published: February 2011

In dilute aqueous solutions, D-glyceraldehyde exists both in the free and hydrated monomeric forms; the equilibrium between them depends on the temperature. The specific rotation of the equilibrium mixture was measured polarimetrically in the temperature range from 20 to 80 °C, the concentrations of both forms being determined by 1H NMR spectroscopy. From these data, the specific rotations of both forms of D-glyceraldehyde in the indicated temperature range were calculated.
One-step synthesis of substituted 2-aryl-2-bromoalkyl-1,3-dioxolanes
Authors: Svoboda Jiří , Paleček Jaroslav , Dědek Václav , Mostecký Jiří
Published: February 2011

Substituted phenones II reacted with ethylene glycol and pyridinium perbromide, phenyltrimethylammonium tribromide, or dioxane dibromide give the corresponding α-bromoacetals I. The highest yields are obtained with dioxane dibromide, and a route is suggested in which the agent is generated in situ. The mass spectra of the compounds I are interpreted.
Photochemical isomerizations of 2-phenyl-1,3-indanedione to E- and Z-benzalphthalide and of E-benzalphthalide to Z-benzalphthalide
Authors: Gáplovský Anton , Donovalová Jana , Hrnčiar Pavel
Published: February 2011

The photochemical isomerizations have been studied of 2-phenyl-1,3-indanedione to mixture of E- and Z-benzalphthalide and of E-benzalphthalide to Z-benzalphthalide depending on the solvent used, concentration, and the light wavelength. The attempts at the reverse photochemical isomerization of E-benzalphthalide to 2-phenyl-1,3-indanedione have failed. Quantum yields of the isomerization of 2-phenyl-1,3-indanedione decrease in the following solvent series: cyclohexane acetonitrile benzene tetrachlormethane methanol. The isomerization quantum yield of 2-phenyl01,3-indanedione is inversely proportional to concentration of the starting substance, but the dependence of 1/φ on the concentration is not linear.
Assignment of 1H and 13C NMR spectra by a combination of homo- and heteronuclear shift correlated two-dimensional NMR. Application to oligosaccharides related to arabinoxylane
Authors: Schraml Jan , Hirsch Ján , Petráková Eva , Krahé Eduard , Bliefert Claus
Published: February 2011

It is shown that a combination of homo- and heteronuclear shift correlated 2 D NMR yields correct and complete assignment of 1H and 13C NMR spectra. The amount of the work necessary can be considerably reduced if some of the lines can be unambiguously assigned on the basis of other information or if suitable model compounds are available.The pattern of homonuclear cross-peaks is characteristic for molecular fragments and can be used with advantage to trace out the lines in the spectral regions with heavy overlap. The exactly assigned 13C chemical shifts of disaccharide and trisaccharide related to arabinoxylan agree satisfactorily with the shifts predicted according to the shifts found in the spectra of model mono- and disaccharides measured under the same conditions.
Preparation of pregnane derivatives from bile acids
Authors: Míčková Růžena
Published: February 2011

The paper describes decarboxylation of derivatives of 3α,12α-dihydroxy-5β-cholanic acid to 24-norchol-22-ene, and conversion of this key intermediate to pregnane derivatives.
Electrochemical investigation of radical-anion reactions of 5-nitro-2-furfuryl derivatives
Authors: Klíma Jiří , Prousek Josef , Ludvík Jiří , Volke Jiří
Published: February 2011

In the studies on nucleophilic substitution of 5-nitro-2-furfuryl derivatives the function of nucleophilic agent was substituted by electrolysis. The electrochemical reduction of these substances and the follow-up reactions of the intermediates were studied by cyclic voltammetry, dc-polarography and ESR spectroscopy. The primary reduction step is the uptake of a single electron giving rise to the radical anion R-CH2-X- which spontaneously splits off the anion X- and forms the neutral 5-nitro-2-furfuryl radical R-CH2.. This radical may either dimerize to 1,2-bis(5-nitro-2-furyl)ethane or yield 5-nitro-2-methylfuran (VI) through abstraction of hydrogen from the solvent or from the supporting electrolyte or through the uptake of an electron and the following protonation. The mechanism found here confirms the validity of the formerly suggested radical-anion mechanism in the nucleophilic substitution of some 5-nitro-2-furfuryl derivatives.
Calculation of dynamics of hydrogen heat desorption from the bed of intermetallide
Authors: Staněk Vladimír , Vychodil Petr , Fateev Genadij Aleksandrovitch , Tarasevitch Vadim Lvovitch
Published: February 2011

Article in Russian
Design of Venturi-tube gas distributors for bubble-type reactors
Authors: Rylek Milan , Zahradník Jindřich
Published: February 2011

The effect of individual parts of a Venturi-tube gas distributor on quality of the gas-liquid dispersion formed was studied in a bubble-type reactor with forced liquid circulation. Gas holdup (bubble-bed porosity) was used as the dispersion characteristics, type and geometry of nozzles, suction chamber arrangement, and dimensions of the mixing tube and diffuser were chosen as variable design parameters. Experimental data of gas holdup presented in dependence on the rate of energy dissipation in the place of dispersion formation characterized then the dispersion efficiency of the Venturi tube at given conditions. Recommendations for design of Venturi-tube gas distributors are presented based upon the results of the study.
Substitution effect in electronic absorption spectra of 2- and 2,6-substituted 4-benzhydrylidene-2,5-cyclohexadien-1-ones
Authors: Musil Lubomír , Koutek Bohumír , Velek Jiří , Souček Milan
Published: February 2011

Electronic absorption spectra of the seventeen fuchsone derivatives Ia-Iq were recorded in n-hexane. The symmetric Gaussian function could be fitted to absorption profiles within the region of the lowest energy π-π* transition. Bad parameters obtained in this way were utilized in calculation of the corresponding oscillator and dipole strengths. The effect of substitution on positions and intensities of all the observed bands was also investigated. The most sensitive response to substituent change is exhibited by the longest wavelength absorption band. The relation between the substituent nature and band position or oscillator strength may be quantified as P sum from i=1 to n (ρiσi) + P0. It follows from the analysis of variance that both the inductive and steric effects are operating. On the other hand, for the non-symmetrically substituted fuchsones, the band intensity characterized by the molar absorption coefficient is a linear function of the inductive effect only. There is no statistically significant contribution of the resonance effect in any of the quantities investigated. The effect of solvent was followed by the separate evaluation of the wavenumbers related to maxima of the longest wavelength band of fuchsones Ia-Iq in the following series of solvents: n-hexane, cyclohexane, isooctane, tetrahydrofurane, acetone, acetonitrile and ethanol.
Studies on the interaction of glutamate dehydrogenase with aporheine
Authors: Kovář Jan , Matyska Luděk
Published: February 2011

The effect was examined of two inhibitors, aporheine and thyroxine, on the kinetics of action of glutamate dehydrogenase in the presence of the coenzyme, NADH, in an inhibiting excess. from the results obtained it appears probable that these two competing ligands do not bind to the regulatory binding site of the enzyme. If the good substrate, glutamate, is replaced by a poor one, such as alanine, aporheine can behave under certain conditions as an activator; this phenomenon is most likely due to fact, like in other cases, that the association of alanine wit the enzyme-coenzyme complex is the slowest step of the reaction. The inhibitory action of aporheine in alkaline media is more complicated than its action at neutral and acidic pH. The sigmoid dependence of inhibition on aporheine concentration is best interpreted as a result of the induction of the second binding site of the enzyme subunit for aporheine after the binding of the first molecule of this ligand. The results obtained indicate the presence of a positive charge localized in the neighborhood of the binding site for the first aporheine molecule and also the important role played by some group of the enzyme with a pK-value about 8 during the induction of the second binding site with a relative high affinity for this ligand.
Minor diterpene components of the defense secretion from the frontal gland of soldiers of the species Nasutitermes costalis (HOLMGREN)
Authors: Valterová Irena , Buděšínský Miloš , Tureček František , Vrkoč Jan
Published: February 2011

Three minor components of the defense secretion from soldiers of the species Nasutermes costalis (HOLMGREN) have been isolated and characterized by means of spectral methods. The first component was identified as 1(15),8(19)-trinervitadien-9β-ol (III), known to occur with the subfamily Nasutitermitinae. For the second component two alternative structures IVa, IVb have been tentatively suggested, both with the 7,16-secotrinervitane skeleton. The third component was determined as 5β,9β-diacetoxy-2-oxo-11(12)kempen-20-oic acid (VII). The kempene skeleton was established on the basis of the 13C NMR spectrum and mass spectral fragmentation of the acid methyl ester. The relative configuration, together with a probable conformation of the tetracyclic framework were determined by 1H NMR. Two major tricyclic components, 1(15),8(19)-trinervitadien-2α,3β-diol (I) and 1(15),8(19)-trinervitadien-2α,3α-diol (II), were further characterized as mono and diacetates. Different rates of acetylation of the hydroxy groups in these diols provided evidence of stable conformation of the six-membered ring within the trinervitane skeleton.
Electrostatic effects on conformational equilibria: Solvation enthalpies and the reaction field theory
Authors: Friedl Zdeněk , Fiedler Pavel , Biroš Ján , Uchytilová Věra , Tvaroška Igor , Böhm Stanislav , Exner Otto
Published: February 2011

Solvation enthalpies of isomeric methyl 2-, 3-, and 4-fluorobenzoates in solvents n-hexane and nitromethane were determined calorimetrically. The enthalpy of the conformational equilibrium ap ⇌ sp of methyl 2-fluorobenzoate was estimated from the temperature dependence of IR spectra and served to calculate the solvation enthalpies of the two conformers, although with a considerable uncertainty. All the results together were discussed in terms of two theories: a) the simple electrostatic approach predicting the reaction enthalphy from the coulombic interaction of atomic charges in an apparently homogenous medium, and b) the extended reaction-field theory expressing the solvation energy as a sum of dipole, quadrupole, cavity, and dispersion terms. In addition, quantum chemical calculations on various levels were carried out. Comparison with experiments revealed that the reaction-field theory, even if extended, reproduces only the general trend in the solvation enthalpies. Of the individual terms particularly the dispersion term is likely to be responsible for the bad fit: it is significant but cannot be satisfactorily predicted by the present theory. Also cavity term is mispresented by theory while it is in fact unimportant for isomeric molecules. The simple electrostatic approach predicts the reaction enthalpy in the gas phase relatively well, i.e. with a similar precision as semiempirical quantum chemical methods. In solvents this approach works worse, but still better than a two-step calculation consisting of the electrostatic gas-phase value and of the reaction-field solvation enthalpy; the latter procedure cannot be generally recommended. Summarizing, our results are in favour of simple theories which yield approximate results of the same quality as the more sophisticated ones, sometimes even better.
Reaction of gallocyanine methyl ester with uranyl ions
Authors: Kotouček Milan , Hrbková Marta
Published: February 2011

The reaction of gallocyanine methyl ester with uranyl ions was studied spectrophotometrically in slightly acid or neutral solutions in 40% (m/m) ethanol. A violet complex of UO2L2 is formed at pH > 5. The conditional stability constants of the complex in the pH 6 - 7.4 range and the equilibrium constants of the coordination reaction were derived from the concentration curves and continuous variations curves. The optimum conditions were sought for the spectrophotometric determination of uranium based on the occurrence of the UO2L2 complex. The relative standard deviation obtained for a uranium concentration of 106 μg l-1 was sr = 2.13%.
Reactions of gallocyanine methyl ester with germanium(IV), tin(IV) and lead(II) ions
Authors: Kotouček Milan , Růžička Josef
Published: February 2011

The reactions of gallocyanine methyl ester with germanium(IV) and tin(IV) in 7.7% (m/m) ethanol and with lead(II) in 15.5% ethanol are studied spectrophotometrically. In slightly acid solutions, complexes of GeL3 (pH 2.5-6.5), SnL2 and SnL3 (pH 1.7-6 in the presence oftartaric acid), and PbL and PbL2 (pH 4-7) are formed. The conditional stability constants of the complexes and the equilibrium constants of the complexation reactions are calculated and procedures are suggested for the photometric determination of tin and for the chelometric determination of lead using visual or photometric indication with gallocyanine methyl ester as metallochromic indicator (colour change from red-violet to blue). A gallocyanine methyl ester-methyl orange screened indicator proved useful for the visual determination of lead, showing an expressive colour change from brown to green.
Partial methylation of methyl 4,6-dideoxy-α- and β-L-ribo-hexopyranosides
Authors: Kefurt Karel , Kefurtová Zdeňka , Jarý Jiří
Published: February 2011

Anomeric methyl 4,6-dideoxy-L-ribo-hexopyranosides I and V, prepared from aldose IX, were etherified with methyl iodide in acetonitrile in the presence of sodium hydroxide. From the products of partial methylation methyl 4,6-dideoxy-2-O-methyl-α-L-ribo-hexopyranoside (II) and methyl 4,6-dideoxy-2,3-di-O-methyl-α-L-ribo-hexopyranoside (IV), or methyl 4,6-dideoxy-2-O-methyl-β-D-ribo-hexopyranoside (VI) and methyl 4,6-dideoxy-2,3-O-methyl-β-L-ribo-hexopyranoside (VIII), respectively, were isolated. The substances were identified by 1H NMR, mass and IR spectra and comparison with standards. The course of etherification of glycosides I and V was checked by gas chromatography and the reactivity of the hydroxyl groups was evaluated by determining the rate constants or their ratios. The observed values were compared with analogous data for other isomers of methyl 4,6-dideoxyhexopyranosides and discussed from the view-point of sterical and polar influence on the reactivity of both their hydroxylic groups.
Acid-base properties of metals and glasses of Na2O.P2O5-xB2O3 system
Authors: Leško Juraj , Dorušková Marie , Tržil Jan
Published: February 2011

Boron oxide in the Na2O.P2O5-x B2O3 system behaves as a Lux base. Its addition to Na2O.P2O5 brings about transformation of a Co(II) indicator from octahedral to tetrahedral configuration, increase in the optical basicity ΛPb(II), increase in the relative basicity of the melt as determined by means of a galvanic cell, and depolymerization reactions releasing PO43- ions. In the Na2O-B2O3 system free of P2O5, boron oxide behaves as a Lux acid. The amphoretic nature of B2O3 is explained in terms of Lux's acid-base theory extended in analogy with the protolysis theory. The theoretical optical basicity values do not indicate the amphoretic behaviour of B2O3 because in this approach boron oxide is a priori regarded as more acidic than Na2O.P2O5.
A study of dipole moments of substituted isothiocyanates of 1,3-diphenyl-2-propen-1-one
Authors: Suchár Gejza , Dzurilla Milan , Kristian Pavol
Published: February 2011

The dipole moments have been measured of various substituted isothiocyanates of 1,3-diphenyl-2-propen-1-one in benzene solution. The measured values have been compared with the dipole moments obtained by the vector addition of the bond dipole moments, and the comparison has been used for a discussion of their electronic structure and interactions of the NCS group.
Formation of sulphur compounds during the hydrodenitrogenation of aniline, cyclohexylamine, benzylamine, and 2-phenylethylamine on a nickel-tungsten catalyst in the presence of hydrogen sulphide
Authors: Černý Mirko , Trka Antonín
Published: February 2011

Hydrodenitrogenations of aniline, cyclohexylamine, benzylamine, and 2-phenylethylamine were performed on a sulphided nickel-tungsten catalyst at 300°C in an autoclave filled with hydrogen in the absence and in the presence of hydrogen sulphide. Due to the presence of hydrogen sulphide the degree of conversion increased from 0.9 to 3,6% for aniline and from 72 to 99% for benzylamine, and the fraction of neutral substances increased from 2.4 to 7% for cyclohexylamine and from 5.0 to 8.9% for 2-phenylethylamine. The neutral fractions contained cyclohexanethiol, thiobenzamide, 2-phenylethanethiol, and other sulphur compounds giving evidence that the increased degree of conversion of the amines was due to the hydrogen sulphide taking direct part in the chemical reaction.
Preparation and biological effects of N-tris(hydroxymethyl)methylaminocarbonylmethyl derivatives of heterocyclic bases
Authors: Pischel Helmut , Holý Antonín , Veselý Jiří , Wagner Günther
Published: February 2011

The title compounds were synthetized by the reaction of TRIS with p-nitrophenyl or alkyl esters of N-carboxymethyl derivatives of uracil, 5-chloro-, 5-bromo-, 5-iodouracil, thymine, cytosine, 6-azauracil, 2-pyridone, 2-pyrimidone, 3-pyridazone and orotic acid. The following novel N-carboxymethyl derivatives are also described: 6-azauracil derivative VIIa by condensation of 4-thio-6-azauracil with methyl bromoacetate followed by hydrolysis, 5-chloruracil derivative IIIa by chlorination of uracil compound IIa, 2-pyrimidone (IXa) and 3-pyridazone derivative Xa by the reaction of the sodium salts of the bases with sodium chloracetate. Of all the amides tested, only the 3-pyridazone derivative Xd and orotic acid derivative XIId inhibited the growth of L-1210 mouse leukemic cells in vitro with 1D50 approx. 10-4 mol l-1.
Papain-catalyzed synthesis of phenylhydrazides of N-acylamino acids
Authors: Čeřovský Václav , Jošt Karel
Published: February 2011

Phenylhydrazides of Nα-acyl derivatives of all coded amino acids, except proline, were prepared by papain (E.C. 3.4.22.2)-catalyzed synthesis. Comparison of yields affords information about the suitability of the amino acid in position P1 in papain-catalyzed syntheses of peptides.
Preparation of 6-amino-6-deoxy-2,3,4,5-tetra-O-methyl-D-gluconic acid and its derivatives
Authors: Kefurt Karel , Kefurtová Zdeňka , Jarý Jiří
Published: February 2011

6-Amino-6-deoxy-2,3,4,5-tetra-O-methyl-D-gluconic acid (I) was prepared by catalytic reduction of 6-azido-6-deoxy-2,3,4,5-tetra -O-methyl-D-gluconic acid (XVI) obtained by alkaline hydrolysis of the corresponding dimethylamine VIII or a mixture of dimethylamide VIII, amide XIV and methylamide XV. Amides VIII, XIV and XV are the products of alkylation of 6-azido-6-deoxy-D-gluconamide (VII) or 6-azido-6-deoxy-3,5-di-O-methyl-D-gluconamide (XIII), carried out with methyl iodide and silver oxide in N,N-dimethylformamide. Amides VII and XIII were prepared by amonolysis of 6-azido-6-deoxy-D-glucono-1,5-lactone (III) or 6-azido-6-deoxy-3,5-di-O-methyl-D-glucono-1,4-lactone (XII). Methylation of 6-amino-6-deoxy-D-gluconolactam (II) with methyl iodide and silver oxide in N,N-dimethylformamide afforded 6-deoxy-2,3,4,5-tetra-O-methyl-6-methylamino-D-gluconolactam (V) from which 6-deoxy-2,3,4,5-tetra-O-methyl-6-methylamino-D-gluconic acid (VI) was prepared.
Modification of the disulfide bridge in cyclic melanotropins
Authors: Lebl Michal , Cody Wayne L. , Wilkes Brian C. , Hruby Victor J. , de L. Castrucci Anna M. , Hadley Mac E.
Published: February 2011

We have prepared a cyclic analog containing a thiomethylene bridge in place of the disulfide bridge in order to further analyze the importance of a cyclic structure for the biological activity of α-MSH (α-melanotropin, α-melanocyte stimulating hormone) and to determine if the biological activity of [Cys4, Cys10]-α-MSH is related to disulfide interchange. The carba analog was based on the highly potent Ac-[Cys4, Cys10]-α-MSH4-13-NH2 fragment analog in which cysteine in residue 4 was replaced by 3-mercaptopropanoic acid (Mpa). This carba analog was slightly less active than the disulfide bridged compound in both in vitro bioassay systems tested (frog and lizard skin systems). Oxidation of the carba analog to the sulfoxide led to a moderate loss of activity in both assays. We also reduced the 4-13 disulfide-containing compound [Mpa4, Cys10]-α-MSH4-13-NH2 and examined the reduced analog for melanotropic activity. It was found that opening of the disulfide led to a large loss of potency. The bis-sulfhydryl compound may have been non-specifically bound to, and/ or internalized inside the tissue, but did not show any inhibitory activity.
Biodegradation of cholesterol by a mutant of the Mycobacterium species
Authors: Schwarz Vladimír , Pihera Pavel , Protiva Jiří , Míčková Růžena
Published: February 2011

The biodegradation of cholesterol by the Mycobacterium mutant CCM 3528 gave rise to 22-hydroxy-23,24-bisnorchola-1,4-diene-3-one (I) as the main product. The identified by-products were 24-norchola-1,4-diene-3,22-dione (IX), androsta-1,4-diene-3,17-dione (XV) and their 4-unsaturated analogues, X and XVI respectively.
Determination of the degree of adsorption and the heat of adsorption for 1-butylamine and ammonia on NaHY zeolites
Authors: Křivánek Miloslav , Jírů Pavel
Published: February 2011

The degree and heat of adsorption of 1-butylamine and ammonia were measured on samples of NaHY zeolites activated at 400-600°C. The adsorption isotherms and calorimetric curves were compared for the two bases, and the amount of Bronsted and Lewis acid centres was determined from the calorimetric curves.
Effect of experimental conditions on the differential thermal-analysis of karnallite type hydrates
Authors: Poilov Vladimir Z. , Ederová Jana , Blažek Antonín
Published: February 2011

Article in Russian
Some 6-substituted 1-[(5R,8S,10R)-8-ergolinyl]-3,3-diethylureas
Authors: Černý Antonín , Křepelka Jiří , Zikán Viktor , Vlčková Drahuše , Vachek Jaroslav , Holubek Jiří , Řežábek Karel , Frühaufová Maria , Šeda Miroslav , Chlebounová Jana , Marhan Otakar
Published: February 2011

6-Substituted 1-[(5R,8S,10R)-8-ergolinyl]-3,3-diethylureas II-VII were prepared from hydrazides of (5R,8S,10R)-6-alkyl-8-ergolinecarboxylic acids (VIIIa, VIIIb) via the corresponding azides IXa and IXb and isocyanates Xa and Xb, and/or from 1-[(5R,8S,10R)-6-methyl-8-ergolinyl]-3,3-diethylurea (I) via XI and XII. Two of the by-products arising in the latter route have been identified (XIII, XIV). Some of the ureas prepared, especially II and III, had strong inhibitory effects in vivo on the secretion of prolactin in rats.
Photochemical 6β-hydroxylation of 11β-hydroxy-4-androstene-3,17-dione
Authors: Kasal Alexander , Smolíková Jorga
Published: February 2011

The utilisability of the photochemical oxygenation of Δ3,5-enol ethers of the type III is limited in 11β-hydroxy derivatives which under the conditions of enol-etherification undergo dehydration to a considerable extent. A method for the protection of the 11β-hydroxy group in the form of a 11-keto group has been elaborated; after the enol-etherification the keto group can be reduced back to the 11β-hydroxy group.
Response gene to complement 32 interacts with Smad3 to promote epithelial-mesenchymal transition of human renal tubular cells
Authors: Guo Xia , Jose Pedro A. , Chen Shi-You
Published: February 2011

Previous studies demonstrate that response gene to complement 32 (RGC-32) mediates transforming growth factor-β1-induced epithelial-mesenchymal transition (EMT) of human renal proximal tubular cells. However, the mechanisms underlying RGC-32 function remain largely unknown. In the present study, we found that RGC-32 function in EMT is associated with Smad3. Coexpression of RGC-32 and Smad3, but not Smad2, induces a higher mesenchymal marker α-smooth muscle actin (α-SMA) protein expression as compared with RGC-32 or Smad3 alone, while knockdown of Smad3 using short hairpin interfering RNA blocks RGC-32-induced α-SMA expression. These data suggest that RGC-32 interacts with Smad3, but not Smad2, in the regulation of EMT. In addition to α-SMA, RGC-32 and Smad3 also synergistically activate the expression of extracellular matrix protein fibronectin and downregulate the epithelial marker E-cadherin. RGC-32 colocalizes with Smad3 in the nuclei of renal proximal tubular cells. Coimmunoprecipitation assays showed that Smad3, but not Smad2, physically interacts with RGC-32 in renal proximal tubular cells. Mechanistically, RGC-32 and Smad3 coordinate the induction of EMT by regulating the EMT regulators Slug and Snail. Taken together, our data demonstrate for the first time that RGC-32 interacts with Smad3 to mediate the EMT of human renal proximal tubular cells.
Effect of dexamethasone on Na+/Ca2+ exchanger in dendritic cells
Authors: Heise Nicole , Shumilina Ekaterina , Nurbaeva Meerim K. , Schmid Evi , Szteyn Kalina , Yang Wenting , Xuan Nguyen Thi , Wang Kan , Zemtsova Irina M. , Duszenko Michael , Lang Florian
Published: February 2011

Ca+-dependent signaling regulates the function of dendritic cells (DCs), antigen-presenting cells linking innate and adaptive immunity. The activity of DCs is suppressed by glucocorticoids, potent immunosuppressive hormones. The present study explored whether the glucocorticoid dexamethasone influences the cytosolic Ca2+ concentration ([Ca2+]i) in DCs. To this end, DCs were isolated from mouse bone marrow. According to fura-2 fluorescence, exposure of DCs to lipopolysaccharide (LPS, 100 ng/ml) increased [Ca2+]i, an effect significantly blunted by overnight incubation with 10 nM dexamethasone before LPS treatment. Dexamethasone did not affect the Ca2+ content of intracellular stores, sarco(endo)plasmic reticulum Ca2+-ATPase (SERCA)2 and SERCA3 expression, ryanodine receptor (RyR)1 expression, or Ca2+ entry through store-operated Ca2+ channels. In contrast, dexamethasone increased the transcript level and the membrane protein abundance of the Na+/Ca2+ exchanger NCX3. The activity of Na+/Ca2+ exchangers was assessed by removal of extracellular Na+ in the presence of external Ca2+, a maneuver triggering the Ca2+ influx mode. Indeed, Na+ removal resulted in a rapid transient increase of [Ca2+]i and induced an outwardly directed current as measured in whole cell patch-clamp experiments. Dexamethasone significantly augmented the increase of [Ca2+]i and the outward current following removal of extracellular Na+. The NCX blocker KB-R7943 reversed the inhibitory effect of dexamethasone on LPS-induced increase in [Ca2+]i. Dexamethasone blunted LPS-induced stimulation of CD86 expression and TNF-α production, an effect significantly less pronounced in the presence of NCX blocker KB-R7943. In conclusion, our results show that glucocorticoid treatment blunts LPS-induced increase in [Ca2+]i in DCs by increasing expression and activity of Na+/Ca2+ exchanger NCX3. The effect contributes to the inhibitory effect of the glucocorticoid on DC maturation.
Elevated seawater Pco2differentially affects branchial acid-base transporters over the course of development in the cephalopodSepia officinalis
Authors: Hu Marian Y. , Tseng Yung-Che , Stumpp Meike , Gutowska Magdalena A. , Kiko Rainer , Lucassen Magnus , Melzner Frank
Published: February 2011

The specific transporters involved in maintenance of blood pH homeostasis in cephalopod molluscs have not been identified to date. Using in situ hybridization and immunohistochemical methods, we demonstrate that Na+/K+-ATPase ( soNKA), a V-type H+-ATPase ( soV-HA), and Na+/HCO3−cotransporter ( soNBC) are colocalized in NKA-rich cells in the gills of Sepia officinalis. mRNA expression patterns of these transporters and selected metabolic genes were examined in response to moderately elevated seawater Pco2(0.16 and 0.35 kPa) over a time course of 6 wk in different ontogenetic stages. The applied CO2concentrations are relevant for ocean acidification scenarios projected for the coming decades. We determined strong expression changes in late-stage embryos and hatchlings, with one to three log2-fold reductions in soNKA, soNBCe, socCAII, and COX. In contrast, no hypercapnia-induced changes in mRNA expression were observed in juveniles during both short- and long-term exposure. However, a transiently increased ion regulatory demand was evident during the initial acclimation reaction to elevated seawater Pco2. Gill Na+/K+-ATPase activity and protein concentration were increased by ∼15% during short (2–11 days) but not long-term (42-days) exposure. Our findings support the hypothesis that the energy budget of adult cephalopods is not significantly compromised during long-term exposure to moderate environmental hypercapnia. However, the downregulation of ion regulatory and metabolic genes in late-stage embryos, taken together with a significant reduction in somatic growth, indicates that cephalopod early life stages are challenged by elevated seawater Pco2.
Voluntary exercise in pregnant rats positively influences fetal growth without initiating a maternal physiological stress response
Authors: Rosa Brielle V. , Firth Elwyn C. , Blair Hugh T. , Vickers Mark H. , Morel Patrick C. H.
Published: February 2011

The effects of increased physical activity during pregnancy on the health of the offspring in later life are unknown. Research in this field requires an animal model of exercise during pregnancy that is sufficiently strenuous to cause an effect but does not elicit a stress response. Previously, we demonstrated that two models of voluntary exercise in the nonpregnant rat, tower climbing and rising to an erect bipedal stance (squat), cause bone modeling without elevating the stress hormone corticosterone. In this study, these same models were applied to pregnant rats. Gravid Wistar rats were randomly divided into three groups: control, tower climbing, and squat exercise. The rats exercised throughout pregnancy and were killed at day 19. Maternal stress was assessed by fecal corticosterone measurement. Maternal bone and soft tissue responses to exercise were assessed by peripheral quantitative computed tomography and dual-energy X-ray absorptiometry. Maternal weight gain during the first 19 days of pregnancy was less in exercised than in nonexercised pregnant control rats. Fecal corticosterone levels did not differ between the three maternal groups. The fetuses responded to maternal exercise in a uterine position-dependent manner. Mid-uterine horn fetuses from the squat exercise group were heavier ( P < 0.0001) and longer ( P < 0.0001) and had a greater placental weight ( P = 0.001) than those from control rats. Fetuses from tower-climbing dams were longer ( P < 0.0001) and had heavier placentas ( P = 0.01) than those from control rats, but fetal weight did not differ from controls. These models of voluntary exercise in the rat may be useful for future studies of the effects of exercise during pregnancy on the developmental origins of health and disease.
Evidence that a higher ATP cost of muscular contraction contributes to the lower mechanical efficiency associated with COPD: preliminary findings
Authors: Layec Gwenael , Haseler Luke J. , Hoff Jan , Richardson Russell S.
Published: February 2011

Impaired metabolism in peripheral skeletal muscles potentially contributes to exercise intolerance in chronic obstructive pulmonary disease (COPD). We used31P-magnetic resonance spectroscopy (31P-MRS) to examine the energy cost and skeletal muscle energetics in six patients with COPD during dynamic plantar flexion exercise compared with six well-matched healthy control subjects. Patients with COPD displayed a higher energy cost of muscle contraction compared with the controls (control: 6.1 ± 3.1% of rest·min−1·W−1, COPD: 13.6 ± 8.3% of rest·min−1·W−1, P = 0.01). Although, the initial phosphocreatine resynthesis rate was also significantly attenuated in patients with COPD compared with controls (control: 74 ± 17% of rest/min, COPD: 52 ± 13% of rest/min, P = 0.04), when scaled to power output, oxidative ATP synthesis was similar between groups (6.5 ± 2.3% of rest·min−1·W−1in control and 7.8 ± 3.9% of rest·min−1·W−1in COPD, P = 0.52). Therefore, our results reveal, for the first time that in a small subset of patients with COPD a higher ATP cost of muscle contraction may substantially contribute to the lower mechanical efficiency previously reported in this population. In addition, it appears that some patients with COPD have preserved mitochondrial function and normal energy supply in lower limb skeletal muscle.
Phosphate overload induces podocyte injury via type III Na-dependent phosphate transporter
Authors: Sekiguchi Sahoko , Suzuki Atsushi , Asano Shogo , Nishiwaki-Yasuda Keiko , Shibata Megumi , Nagao Shizuko , Yamamoto Naoki , Matsuyama Mutsushi , Sato Yutaka , Yan Kunimasa , Yaoita Eishin , Itoh Mitsuyasu
Published: February 2011

Uptake of Piat the cellular membrane is essential for the maintenance of cell viability. However, phosphate overload is also stressful for cells and can result in cellular damage. In the present study, we investigated the effects of the transgenic overexpression of type III Pitransporter Pit-1 to explore the role of extracellular Piin glomerular sclerosis during chronic renal disease. Pit-1 transgenic (TG) rats showed progressive proteinuria associated with hypoalbuminemia and dyslipidemia. Ultrastructural analysis of TG rat kidney by transmission electron microscopy showed a diffuse effacement of the foot processes of podocytes and a thickening of the glomerular basement membrane, which were progressively exhibited since 8 wk after birth. TG rats died at 32 wk of age due to cachexia. At this time, more thickening of the glomerular basement membrane and segmental sclerosis were observed in glomeruli of the TG rats. Immunohistochemical examination using anti-connexin 43 and anti-desmin antibodies suggested the progressive injury of podocytes in TG rats. TG rats showed higher Piuptake in podocytes than wild-type rats, especially under low Piconcentration. When 8-wk-old wild-type and TG rats were fed a 0.6% normal phosphate (NP) or 1.2% phosphate (HP) diet for 12 wk, HP diet-treated TG rats showed more progressive proteinuria and higher serum creatinine levels than NP diet-treated TG rats. In conclusion, our findings suggest that overexpression of Pit-1 in rats induces phosphate-dependent podocyte injury and damage to the glomerular barrier, which result in the progression of glomerular sclerosis in the kidney.
Peripheral nerve damage does not alter release properties of developing central trigeminal afferents
Authors: Lo Fu-Sun , Erzurumlu Reha S.
Published: February 2011

The infraorbital branch of the trigeminal nerve (ION) is essential in whisker-specific neural patterning (“barrelettes”) in the principal nucleus of the trigeminal nerve (PrV). The barrelettes are formed by the ION terminal arbors, somata, and dendrites of the PrV cells; they are abolished after neonatal damage to the ION. Physiological studies show that disruption of the barrelettes is accompanied by conversion of functional synapses into silent synapses in the PrV. In this study, we used whole cell recordings with a paired-pulse stimulation protocol and MK-801 blocking rate to estimate the presynaptic release probability (Pr) of ION central trigeminal afferent terminals in the PrV. We investigated Pr during postnatal development, following neonatal ION damage, and determined whether conversion of functional synapses into silent synapses after peripheral denervation results from changes in Pr. The paired-pulse ratio (PPR) was quite variable ranging from 40% (paired-pulse depression) to 175% (paired-pulse facilitation). The results from paired-pulse protocol were confirmed by MK-801 blocking rate experiments. The nonuniform PPRs did not show target cell specificity and developmental regulation. The distribution of PPRs fit nicely to Gaussian function with a peak at ∼100%. In addition, neonatal ION transections did not alter the distribution pattern of PPR in their central terminals, suggesting that the conversion from functional synapses into silent synapses in the peripherally denervated PrV is not caused by changes in the Pr.
Mechano- and thermosensitivity of injured muscle afferents
Authors: Kirillova Irina , Rausch Vanessa H. , Tode Jan , Baron Ralf , Jänig Wilfrid
Published: February 2011

Injury of limb nerves leading to neuropathic pain mostly affects deep somatic nerves including muscle nerves. Here, we investigated the functional properties of injured afferent fibers innervating the lateral gastrocnemius-soleus muscle 4–13 h [time period (TP) I] and 4–7 days (TP II) after nerve crush in anesthetized rats using neurophysiological recordings from either the sciatic nerve (165 A-, 137 C-fibers) or the dorsal root L5 (43 A-, 28 C-fibers). Ongoing activity and responses to mechanical or thermal stimulation of the injury site of the nerve were studied quantitatively. Of the electrically identified A- and C-fibers, 5 and 38% exhibited ectopic activity, respectively, in TP I and 51 and 61%, respectively, in TP II. Thus all afferent fibers in an injured muscle nerve developed ectopic activity since ∼50% of the fibers in a muscle nerve are somatomotor or sympathetic postganglionic. Ongoing activity was present in 50% of the afferent A-fibers (TP II) and in 53–56% of the afferent C-fibers (TP I and II). In TP II, mechanical, cold, and heat sensitivity were present in 91, 63, and 52% of the afferent A-fibers and in 50, 40, and 66% of the afferent C-fibers. The cold and heat activation thresholds were 5–27 and 35–48°C, respectively, covering the noxious and innocuous range. Most afferent fibers showed combinations of these sensitivities. Mechano- and cold sensitivity had a significantly higher representation in A- than in C-fibers, but heat sensitivity had a significantly higher representation in C- than in A-fibers. These functional differences between A- and C-fibers applied to large- as well as small-diameter A-fibers. Comparing the functional properties of injured muscle A- and C-afferents with those of injured cutaneous A- and C-afferents shows that both populations of injured afferent neurons behave differently in several aspects.
Improved stimulus representation by short interspike intervals in primary auditory cortex
Authors: Shih Jonathan Y. , Atencio Craig A. , Schreiner Christoph E.
Published: February 2011

We analyzed the receptive field information conveyed by interspike intervals (ISIs) in the auditory cortex. In the visual system, different ISIs may both code for different visual features and convey differing amounts of stimulus information. To determine their potential role in auditory signal processing, we obtained extracellular recordings in the primary auditory cortex (AI) of the cat while presenting a dynamic moving ripple stimulus and then used the responses to construct spectrotemporal receptive fields (STRFs). For each neuron, we constructed three STRFs, one for short-ISI events (ISI < 15 ms); one for isolated, long-ISI events (ISI > 15 ms); and one including all events. To characterize stimulus encoding, we calculated the feature selectivity and event information for each of the STRFs. Short-ISI spikes were more feature selective and conveyed information more efficiently. The different ISI regimens of AI neurons did not represent different stimulus features, but short-ISI spike events did contribute over-proportionately to the full spike train STRF information. Thus short-ISIs constitute a robust representation of auditory features, and they are particularly effective at driving postsynaptic activity. This suggests that short-ISI events are especially suited to provide noise immunity and high-fidelity information transmission in AI.
Suspected Nonalcoholic Fatty Liver Disease Is Not Associated with Vitamin D Status in Adolescents after Adjustment for Obesity
Authors: Katz Karin , Brar Preneet Cheema , Parekh Niyati , Liu Ying-Hua , Weitzman Michael
Published: February 2011

This study investigated a potential independent association between hypovitaminosis D and suspected nonalcoholic fatty liver disease (NAFLD) in a nationally representative sample of the US adolescents. Data from 1630 subjects 12–19 years of age were examined using the National Health and Nutrition Examination Survey, 2001–2004. The vitamin D status of subjects was categorized into quartiles of serum 25-hydroxyvitamin D. Subjects with serum  U/L were classified as having suspected NAFLD. Data regarding age, sex, race, BMI, and poverty level were also analyzed in bivariate and multivariate analyses using SAS and SUDAAN software. Suspected NAFLD was identified in 12.1% of adolescents in the lowest quartile compared to 6.9% of adolescents in the second quartile, 8.0% in the third quartile, and 13.17% in the highest quartile of serum 25(OH)D concentrations (). In analyses utilizing vitamin D as a continuous variable, no independent association was found between Vitamin D levels and rates of elevated ALT levels. In multivariate analyses, higher risks for suspected NAFLD were observed in males and overweight adolescents; however, vitamin D status was not found to be independently associated with suspected NAFLD after adjusting for obesity.
Investigation of the Influence of Hydrocyclone Geometric and Flow Parameters on Its Performance Using CFD
Authors: Motsamai Oboetswe Seraga
Published: February 2011

Effectiveness and efficiency of hydro-cyclone separators are highly dependent on their geometrical parameters and flow characteristics. Performance of the hydro-cyclone can, therefore, be improved by modifying the geometrical parameters or flow characteristics. The mining and chemical industries are faced with problems of separating ore-rich stones from the nonore-rich stones. Due to this problem a certain amount of precious metals is lost to the dumping sites. Plant managers try to solve these problems by stockpiling what could be useless stones, so that they can be reprocessed in the future. Reprocessing is not a sustainable approach, because the reprocessed material would give lower yield as compared to the production costs. Particulate separation in a hydro-cyclone has been investigated in this paper, by using computational fluid dynamics. The paper investigated the influence of various flow and geometric parameters on particulate separation. Optimal parameters for efficient separation have been determined for the density of fluid, diameter of the spigot, and diameter of the vortex finder. The principal contribution of this paper is that key parameters for design optimization of the hydro-cyclone have been investigated.
eEF-2 Kinase Dictates Cross-Talk between Autophagy and Apoptosis Induced by Akt Inhibition, Thereby Modulating Cytotoxicity of Novel Akt Inhibitor MK-2206
Authors: Cheng Yan , Ren Xingcong , Zhang Yi , Patel Rajesh , Sharma Arati , Wu Hao , Robertson Gavin P. , Yan Li , Rubin Eric , Yang Jin-Ming
Published: February 2011

Inhibition of the survival kinase Akt can trigger apoptosis, and also has been found to activate autophagy, which may confound tumor attack. In this study, we investigated regulatory mechanisms through which apoptosis and autophagy were modulated in tumor cells subjected to Akt inhibition by MK-2206, the first allosteric small molecule inhibitor of Akt to enter clinical development. In human glioma cells, Akt inhibition by MK-2206 or siRNA-mediated attenuation strongly activated autophagy, whereas silencing of eukaryotic elongation factor-2 (eEF-2) kinase, a protein synthesis regulator, blunted this autophagic response. Suppression of MK-2206–induced autophagy by eEF-2 silencing was accompanied by a promotion of apoptotic cell death. Similarly, siRNA-mediated inhibition of eEF-2 kinase potentiated the efficacy of MK-2206 against glioma cells. Together, these results showed that blunting autophagy and augmenting apoptosis by inhibition of eEF-2 kinase could modulate the sensitivity of glioma cells to Akt inhibition. Our findings suggest that targeting eEF-2 kinase may reinforce the antitumor efficacy of Akt inhibitors such as MK-2206. Cancer Res; 71(7); 2654–63. ©2011 AACR.
HER2 Protein and Gene Variation between Primary and Metastatic Breast Cancer: Significance and Impact on Patient Care
Authors: Fabi Alessandra , Di Benedetto Anna , Metro Giulio , Perracchio Letizia , Nisticò Cecilia , Di Filippo Franco , Ercolani Cristiana , Ferretti Gianluigi , Melucci Elisa , Buglioni Simonetta , Sperduti Isabella , Papaldo Paola , Cognetti Francesco , Mottolese Marcella
Published: February 2011

Purpose: To analyze HER2 status in primary breast cancer (PBC) compared with correspondent metachronous metastases and to investigate whether BC phenotype may be predictive of change in HER2 expression.

Experimental Design: HER2 was investigated by immunohistochemistry, silver in situ hybridization (SISH), and FISH, in a series of 137 tumors, building up a tissue microarray to concurrently analyze each single PBC and metastatic (MBC) on the same slide.

Results: HER2 status was discordant in 14 cases (10%): 12 negative in PBC and positive in metastases and two positive in PBC and negative in metastases (P = 0.04). These findings were confirmed by a PCR based test termed Multiplex Ligation-dependent Probe Amplification (MLPA). HER2 status changed in hormone receptor-positive BC more frequently than in negative ones (P = 0.002). In addition, we evaluated HER2 gene and chromosome 17 copy number by SISH in the 123 cases with unchanged HER2 status during progression. We found consistent HER2 gene copy number stability in the 100 nonamplified cases. Conversely, of the 23 amplified PBC, 13 (57%) demonstrated a significant increase in the HER2 gene and chromosome 17 copy number in their paired metastases (P = 0.01), as defined by SISH (k = 0.54, P < 0.0001) and MLPA. Patients who changed HER2 status from negative to positive, presented significant longer time to progression when treated with trastuzumab compared to those who were untreated (P = 0.04).

Conclusions: When feasible, HER2 reassessment in metastatic lesions should be carefully taken into account, especially for metastases coming from primary hormone receptor-positive BC. Clin Cancer Res; 17(7); 2055–64. ©2011 AACR.