bluuebunny/crossref_metadata_2025 huggingface dataset:
Pseudorabies Virus UL36 Tegument Protein Physically Interacts with the UL37 Protein
Authors: Klupp Barbara G. , Fuchs Walter , Granzow Harald , Nixdorf Ralf , Mettenleiter Thomas C.
Published: July 2002

The UL36 open reading frame encoding the tegument protein ICP1/2 represents the largest open reading frame in the genome of herpes simplex virus type 1 (HSV-1). Polypeptides homologous to the HSV-1 UL36 protein are present in all subfamilies of
Herpesviridae
. We sequenced the UL36 gene of the alphaherpesvirus pseudorabies virus (PrV) and prepared a monospecific polyclonal rabbit antiserum against a bacterial glutathione
S
-transferase (GST)-UL36 fusion protein for identification of the protein. The antiserum detected a >300-kDa protein in PrV-infected cells and in purified virions. Interestingly, in coprecipitation analyses using radiolabeled infected-cell extracts, the anti-UL36 serum reproducibly coprecipitated the UL37 tegument protein, and antiserum directed against the UL37 protein coprecipitated the UL36 protein. This physical interaction could be verified using yeast two-hybrid analysis which demonstrated that the UL37 protein interacts with a defined region within the amino-terminal part of the UL36 protein. By use of immunogold labeling, capsids which accumulate in the cytoplasm in the absence of the UL37 protein (B. G. Klupp, H. Granzow, E. Mundt, and T. C. Mettenleiter, J. Virol. 75:8927-8936, 2001) as well as wild-type intracytoplasmic and extracellular virions were decorated by the anti-UL36 antiserum, whereas perinuclear primary enveloped virions were not. We postulate that the physical interaction of the UL36 protein, which presumably constitutes the innermost layer of the tegument (Z. Zhou, D. Chen, J. Jakana, F. J. Rixon, and W. Chiu, J. Virol. 73:3210-3218, 1999), with the UL37 protein is an important early step in tegumentation during virion morphogenesis in the cytoplasm.
Role of RNA in Facilitating Gag/Gag-Pol Interaction
Authors: Khorchid Ahmad , Halwani Rabih , Wainberg Mark A. , Kleiman Lawrence
Published: July 2002

We have examined the influence of RNA upon the interaction of Gag-Pol with Gag during human immunodeficiency virus type 1 (HIV-1) assembly. COS7 cells were transfected with protease-negative HIV-1 proviral DNA, and Gag/Gag-Pol complexes were detected by coimmunoprecipitation with anti-integrase. In COS7 cells, Gag/Gag-Pol is found almost entirely in pelletable, membrane-bound complexes. Exposure of cells to 1% Triton X-100 releases Gag/Gag-Pol from bulk membrane, but the complexes remain pelletable. The role of RNA in facilitating the interaction between Gag and Gag-Pol was examined in these bulk membrane-free, pelletable complexes. The specific presence of viral genomic RNA is not required to maintain the Gag/Gag-Pol interaction, but some type of RNA is, since exposure to RNase destabilized the Gag/Gag-Pol complex. When present only in Gag, the nucleocapsid mutation R7R10K11S, which inhibits Gag binding to RNA, inhibits the formation of both Gag and Gag/Gag-Pol complexes. When present only in Gag-Pol, this mutation has no effect upon complex formation. This result indicates that Gag-Pol may not interact directly with RNA but rather requires RNA-facilitated Gag multimerization for its interaction with Gag.
Saturated Solutions of M(NO3)2-H2O-CH3OH (M = Sr, Ba) Systems
Authors: Stoev Mitko D. , Robledo Jóse M. A.
Published: July 2002

The solubility isotherms of the M(NO3)2 - H2O - CH3OH (M = Sr, Ba) systems at 25 °C have been studied. Crystallization fields of the equilibrium existence of the salts Sr(NO3)2 .4 H2O, Sr(NO3)2 and Ba(NO3)2 have been found. The structures of the saturated solutions on the basis of statistic calculations and IR spectra have been discussed.
Intercalation of Anhydrous Vanadyl Phosphate with Aliphatic Alcohol Mixtures
Authors: Beneš Ludvík , Zima Vítězslav , Kalousová Jaroslava , Votinský Jiří
Published: July 2002

The intercalation of VOPO4 with the mixtures of alcohols (ethanol and 1-butanol, methanol and ethanol, methanol and 1-propanol, methanol and 1-butanol) have been studied. The dependence of alcohols content and interlayer distance of the intercalates formed on composition of the starting mixtures of alcohols has been found. The ability of VOPO4 to form mixed intercalates with alcohols is discussed.
Transport Behaviour of Ions in N,N-Dimethylformamide and Dimethyl Sulfoxide at Different Temperatures. Conductance Studies
Authors: Chauhan Mohinder S. , Sharma Manita , Gupta Sanjay , Ashwini K. , Chauhan Suvarcha
Published: July 2002

Molar conductivities of Bu4NBPh4, Bu4NNO3, LiNO3, NaNO3, KNO3 and AgNO3 have been reported in pure DMF and DMSO in the temperature range from 20 to 45 °C. The conductance data have been analyzed in terms of limiting molar conductivity Λ0 and ion-association constant KA. Separation of Λ0 into ionic components Λi 0 has been carried out on the basis of Bu4NBPh4 assumption in order to calculate the effective ionic radii ri in DMF and DMSO. Examination of ri values of K+ and Ag+ ions as a function of temperature revealed some specific interactions of Ag+ ion with DMF and DMSO. In DMSO electrostatic ion-dipole interaction of Li+, Na+ and K+ ions is found to be somewhat modified due to dipole-dipole interaction.
Crystal and Molecular Structure Determination of N,N'-Diphenylacetamidinium Trifluoroacetate
Authors: Ondráček Jan , Pakhomova Svetlana , Kratochvíl Bohumil , Smrčková Svatava
Published: July 2002

The structure of N,N'-diphenylacetamidinium trifluoroacetate - a model of the lactate dehydrogenase binding site - was solved by direct methods and anisotropically refined to R = 0.032 for 1 475 unique observed reflections. The compound crystallizes in the monoclinic space group P21/m, a = 5.942(1), b = 17.256(2), c = 7.817(1) Å, β = 103.05(1)°, V = 780.8(1) Å3, Z = 2, Dcalc = 1.38 g cm-3, μ(MoKα) = 0.11 mm-1, F(000) = 336.
Polarographic and Voltammetric Determination of 4,4'-Bis[(4-phenylamino-6-morpholino-1,3,5-triazin-2-yl)amino]stilbene-2,2'-disulfonic Acid
Authors: Barek Jiří , Hrnčíř Roman , Moreira Josino C. , Zima Jiří
Published: July 2002

The polarographic and voltammetric behaviour of the title compound, which is the basic component in many commercial optical whitening agents, was investigated. The optimum conditions were found for the determination of the substance in dimethylformamide solutions containing 5% (v/v) water by tast polarography, differential pulse polarography, linear sweep voltammetry using a hanging mercury drop electrode, and differential pulse polarography using a hanging mercury drop electrode over the concentration regions of 100-500, 10-500, 10-500, and 1-100 mmol l-1, respectively. Practical applicability of the newly developed methods to the determination of the analyte in technical products, either direct or following separation by thin layer chromatography, was verified.
Kinetics of Coupling of 4-Methoxybenzenediazonium Ion with 2,6-Dihydroxypyridine
Authors: Horáčková Jaroslava , Štěrba Vojeslav
Published: July 2002

The kinetics of reaction of 4-methoxybenzenediazonium ion (3) with 2,6-dihydroxypyridine (1) has been studied in methoxyacetate, acetate, and phosphate buffers. The rate-limiting step is the formation of the reaction intermediate and not the splitting off of the proton (which was detected in the cases of citrazinic acid and its methyl ester). Therefrom it follows that for 2,6-dihydroxypyridine derivatives the steric hindrance to the formation of the Wheland intermediate exerted by CO2- and CO2CH3 groups represents a necessary condition for the rate-limiting splitting off of the proton and, hence, for the existence of general base catalysis.
HPLC of Platinum Metals and Gold Based on Their Bromo Complexes
Authors: Doležal Josef , Sommer Lumír
Published: July 2002

PtII,IV, PdII, and AuIII can be separated and quantitated by HPLC in the form of ion-associates of their bromo complexes with the cetyltrimethylammonium (CTMA) cation, using the acetonitrile-water 60 : 40 system containing 0.002 mol l-1 CTMA and 0.05 mol l-1 NaBr (pH 3) as the mobile phase and detection at 240 nm. In such circumstances the detection limits for the injection of 20 μl sample are 6.7, 0.4, 0.9, and 4.3 ng for PtII, PtIV, PdII, and AuIII, respectively. Excess Fe3+, Al3+, Mg2+, Ca2+, NO3-, SO42-, and Cl- does not interfere. On-line preconcentration of the PtII,IV bromo complexes on Separon SGX RPS is recommended.
Computer Simulation of Electron Spin Resonance Spectra of Ge25S75and Ge30S70 Bulk Glasses
Authors: Černošek Zdeněk , Liška Marek , Pelikán Peter , Černošková Eva , Valko Marián , Frumar Miloslav
Published: July 2002

The electron spin resonance (ESR) spectra of bulk glasses of the chemical composition Ge25S75 and Ge30S70 were measured at liquid nitrogen temperature and subjected to computerized separation. The complex ESR spectra of both glasses were found to represent a superposition of three paramagnetic defect spectra, two with orthorhombic tensors g and one with the axial tensor g. The former two paramagnetic centers can be related to a two-atomic defect of the sulfur-sulfur type, the latter to a germanium-sulfur defect. The experimental results are in a good agreement with the non-dangling bond model of paramagnetic defects in Ge-S glasses.
Analytical Solutions of the Schrödinger Equation. Ground State Energies and Wave Functions
Authors: Dvořák Jan , Skála Lubomír
Published: July 2002

It is shown that there are two generalizations of some well-known analytically solvable problems leading to exact analytical solutions of the Schrödinger equation for the ground state and a few low lying excited states. In this paper, the ground state energies and wave functions are discussed.
Accessibility of Tyrosine Residues in Cytochrome P-450scc (CYP11A1)
Authors: Anzenbacher Pavel , Hudeček Jiří , Lange Reinhard , Bancel Frédéric
Published: July 2002

Cytochrome P-450scc (CYP11A1) is known to exist in various conformational states. To study the accessibility of tyrosine residues to the solvent, second and fourth derivatives of cytochrome absorption spectra in the ultraviolet region were used. The measurements were carried out in the temperature range -10 to 40 °C and at two pH values (6.8 and 7.4). Our results indicate that the tyrosine residues of this enzyme are less accessible at higher temperatures as well as at higher pH, that is at conditions where the conformational equilibrium shifts to low-spin Fe(III) form(s). In other words, a more compact structure is attributable to the low-spin Fe(III) form(s) of P-450scc.
Densities and Excess Volumes in Binary Mixtures of Heptane with 1-Chloropropane, 1-Chlorobutane, 1-Chloropentane, or 1-Chlorohexane at 298.15 K
Authors: Kovács Éva , Linek Jan
Published: July 2002

Densities and excess molar volumes, VE, of heptane-1-chloropropane, heptane- 1-chlorobutane, heptane-1-chloropentane, and heptane-1-chlorohexane systems are reported at 298.15 K and atmospheric pressure over the whole composition range. Value of VE was found to be slightly negative at lower mole fractions and slightly positive at higher mole fractions in case of the heptane-1-chlorohexane system. For all the other systems, VE was positive. The VE results were correlated using the fourth-order Redlich-Kister equation, the maximum likelihood procedure being applied for evaluating the adjustable parameters.
N,S-Chelating Amino-ortho-carboranethiolate Complexes of Rhodium and Iridium: Synthesis and Reactivity. X-Ray Crystal Structures of (η4-C8H12)Rh[(NMe2CH2)SC2B10H10] and (CO)2Rh[(NMe2CH2)SC2B10H10]
Authors: Chung Seung-Won , Ko Jaejung , Park Kwonil , Cho Sungil , Kang Sang Ook
Published: July 2002

The reaction of [M(μ-Cl)(cod)]2 (M = Rh, Ir; cod = cycloocta-1,5-diene) with two equivalents of the lithium ortho-carboranethiolate derivative LiCabN,S 2 [LiCabN,S = closo-2-(dimethylaminomethyl)-1-(lithiumthiolato)-ortho-carborane] produced the four-coordinated metallacyclic compounds, CabN,SM(cod) 3 (M = Rh 3a, Ir 3b), in which the metal atom was stabilized via intramolecular N,S-coordination. These new compounds have been isolated in high yields and characterized by IR and NMR spectroscopy. The structure consists of an amino-ortho-carboranethiolate fragment bonded to (cod)Rh(I) via nitrogen and sulfur, so as to give the metal a square-planar environment. Subsequent carbonylation reactions of 3a, 3b result in the quantitative formation of the corresponding (amino-ortho-carboranethiolato)(carbonyl)metal N,S-chelates CabN,SM(CO)2 4 (M = Rh 4a, Ir 4b). The metal carbonyl complexes 4a, 4b have been isolated and characterized by spectroscopic and compound 4a also by X-ray diffraction techniques. The molecular structure of 4a reveals that the rhodium atom is coordinated by nitrogen and sulfur atoms of the amino-ortho-carboranethiolate ligand, and two carbonyl ligands complete the coordination of the metal atom.
Computational Parameters in Correlation Analysis: Gas-Water Distribution Coefficient
Authors: Famini George R. , Benyamin Dalia , Kim Christina , Veerawat Rattiporn , Wilson Leland Y.
Published: July 2002

Theoretical linear solvation energy relationships (TLSER) combine computational molecular parameters with the linear solvation energy relationship (LSER) of Kamlet and Taft to characterize and predict properties of compounds. This paper examines the correlation of the gas-water equilibrium constant for 423 compounds with the TLSER parameters. Also, it describes new parameters designed to improve the TLSER information content.
Effects of ortho-Substituents in Protonolysis of Arylmercuric Chlorides with Hydrochloric Acid
Authors: Wang Yulan , Wu Yangjie
Published: July 2002

The kinetics of reaction of ortho-substituted phenylmercuric chlorides, 2-R-C6H4HgCl (R = H, CH3, CH3O, C2H5O, CF3, COOC2H5, Cl, Br, F, NO2), with hydrochloric acid in absolute ethanol in the presence of sodium iodide has been studied. The reaction is of the overall second order, first order with respect to each reactant. The rate constant determined at a fixed temperature decreases in the order of R: C2H5O > CH3O > CH3 > H > COOC2H5 > F > Cl > Br > CF3 > NO2. The role of inductive, resonance and field effects of the ortho-substituents, and the relation between steric demands of the ortho-substituents and volume of attacking species are discussed. The underlying mechanism is proposed on the basis of experimental results.
Purification and Characterisation of a Vitellogenin Derived Aminopeptidase from Rainbow Trout Eggs
Authors: Kronovetr Jakub , Barthová Jana , Barth Tomislav , Ryšlavá Helena
Published: July 2002

An aminopeptidase specific for N-terminal alanine was isolated from the rainbow trout (Oncorhynchus mykiss) maturing eggs using a simple procedure. The enzyme is composed of two identical units each of MW 16 000, separable by disulfide reduction. The enzyme has a high content of acid amino acids and its N-terminal sequence is the following 1EVNAVKCSMV10RDTLTTFNNK20KYQIN25. The sequence is identical with that of the rainbow trout vitellogenin precursor beginning with the amino acid in position 1 385. No peptidase activity has been so far observed in proteins derived from this precursor. The enzyme activity is partially blocked by Na4-EDTA but it is not inactivated by 4-(chloromercuri)benzoate, phenylmethanesulfonyl fluoride or pepstatin A.
Synthesis and Crystal Structure Determination of Cyclosporin H
Authors: Jegorov Alexandr , Cvak Ladislav , Husek Aleš , Šimek Petr , Heydová Anna , Ondráček Jan , Pakhomova Svetlana , Hušák Michal , Kratochvíl Bohumil , Sedmera Petr , Havlíček Vladimír
Published: July 2002

Acid-catalyzed degradation of cyclosporin A was studied in various solvents and products of reaction were monitored by HPLC. Identification of amino acids and their chirality were determined after hydrolysis and derivatization by GC-MS. Cyclosporin H was isolated as the principal product and its structure was determined by X-ray diffraction: Cyclosporin H- diethyl ether-water (1 : 0.5 : 1) crystallizes in the monoclinic space groupI2witha= 12.338(2) Å,b= 18.963(2) Å,c= 34.074(3) Å, β = 96.47(2)°,Z= 4, andV= 7 921.4(17) Å3.
Thermodynamics of Micellization of Hexadecylpyridinium Bromide in Aqueous and Alcoholic (C1-C4) Solutions
Authors: Oremusová Jarmila , Greksáková Olga , Peterek Karel
Published: July 2002

In this work, we studied effects of temperature, alkyl chain, branching and increasing number of hydroxy groups of aditives on the critical micelle concentration (CMC) and thermodynamics of micellization of 1-hexadecylpyridinium bromide (CPBr) using conductometric techniques in a series of solvents: water and C1-C4alcohols (methyl (MeOH), ethyl (EtOH), n-propyl (n-PrOH), isopropyl (i-PrOH), n-butyl (n-BuOH), isobutyl (i-BuOH),tert-butyl alcohol (t-BuOH), 1,2-ethanediol (EtdOH), 1,2-propanediol (PrdOH) and 1,2,3-propanetriol (PrtOH)). From the conductivity curves measured in water and alcohols in the temperature interval 20-50 °C, the CMC and concentrations of CPBr corresponding to a change of the micelle shape were calculated. For alcohols, the plots of the CMCvstemperature display U-shaped curves with minima at 30 °C, whereas in water, the CMC increases nonlinearly over the temperature interval studied. According to their effect on the CMC, the solvents can be arranged in the order H2O < n-BuOH < i-BuOH <t-BuOH < PrtOH < n-PrOH < i-PrOH < PrdOH < EtOH < EtdOH < MeOH. Degrees of counterion binding (β), as calculated from slopes of the conductivity curves, were found to decrease as the temperature increases. Thermodynamic functions of micellization - standard molar Gibbs energy, enthalpy and entropy - were analyzed in terms of the model of phase separation as well as the model based on the mass-action law. While the drop in the ∆mG0values over the given temperature interval is only 1-2 kJ mol-1, the lowering of ∆mH0and ∆mS0is much more pronounced. Enthalpy-entropy compensation plots were used to calculated the compensation temperatures which characterise the solvent-solute interaction and lie in the range 289-313 K. The reference temeratures for ∆mS0converging to zero range from 318 to 344 K. The values of molar heat capacity ∆mCPwere also calculated. In the mixed (water-alcohol-tenside) solutions with the volume alcohol-water ratios φ = 0-1.0, the CMC were determined at 25 °C.
Influence of Metal Core Composition on Redox Properties and Photoreactivity of the Clusters [H4-xRu4-xRhx(CO)12] (x = 0, 2, 3, 4)
Authors: Bakker Maarten J. , Pakkanen Tapani A. , Hartl František
Published: July 2002

Electrochemical properties of tetrahedral clusters [H2Ru2Rh2(CO)12], [HRuRh3(CO)12] and [Rh4(CO)12] were investigated in order to evaluate the influence of metal core composition in the series [H4-xRu4-xRhx(CO)12] (x = 0-4). The cluster [H3Ru3Rh(CO)12] was not available in sufficient quantities. As reported for [H4Ru4(CO)12], electrochemical reduction of the hydride-containing clusters [H2Ru2Rh2(CO)12] and [HRuRh3(CO)12] also results in (stepwise) loss of hydrogen, producing the anions [HRu2Rh2(CO)12]-, [Ru2Rh2(CO)12]2- and [RuRh3(CO)12]-. These anions can also be prepared from the neutral parent clusters via chemical routes. Electrochemical reduction of [Rh4(CO)12] does not result in the formation of any stable tetranuclear anion. Instead, [Rh5(CO)15]- and [Rh6(CO)15]2- are the major reduction products detected in the course of IR spectroelectrochemical experiments. Most likely, these cluster species are formed from the secondary CO-loss product [Rh4(CO)11]2- by fast redox condensation reactions. Their reoxidation regenerates parent [Rh4(CO)12], together with some [Rh6(CO)16]. Unlike [H4Ru4(CO)12] that undergoes photochemical CO-dissociation, [H2Ru2Rh2(CO)12] and [Rh4(CO)12] are completely photostable in neat hexane and dichloromethane as well as in the presence of oct-1-ene.
Transformation of 8-[(2-Hydroxyalkyl)sulfanyl]adenines to 6-Amino-7H-purin-8(9H)-one Derivatives
Authors: Janeba Zlatko , Holý Antonín , Masojídková Milena
Published: July 2002

Alkylation of 6-amino-7H-purin-8(9H)-thione (8-sulfanyladenine, 1) with one equivalent of (R)-[(trityloxy)methyl]oxirane gave its S-alkyl derivative 2, which was converted to the 6-amino-7H-purin-8(9H)-one (3), while alkylation of 1 with two equivalents of (S)-[(trityloxy)methyl]oxirane afforded a mixture of N3,S-dialkylated product 4a, N9-monoalkyl and N7,N9-dialkyl derivatives of 6-amino-7H-purin-8(9H)-one, 5a and 6a, respectively. This approach can be used for rapid and easy transformation of 8-[(2-hydroxyalkyl)sulfanyl]adenines to the derivatives of 6-amino-7H-purin-8(9H)-one (8-hydroxyadenine) using NaH or Cs2CO3 in DMF. The course of the S→O transformation strictly depends on the character of the starting compounds and on the reaction conditions. N9-Alkyl-8-[(2-hydroxyalkyl)sulfanyl]adenines 10, 12, 14 and 17 were rapidly converted to the corresponding 6-amino-7H-purin-8(9H)-one derivatives 11, 13, 11 and 18, respectively. N9-Unsubstituted 2 reacts slowly, and N3-alkyl derivative 4a is stable under the same reaction conditions. The described transformation does not occur when the hydroxy group in 8-[(2-hydroxyalkyl)sulfanyl]adenine derivative 15 is protected. The reaction using NaH proceeds more rapidly than that using Cs2CO3.
Molybdenum-Catalyzed Allylic Substitution in Glycals: A C-C Bond-Forming Ferrier-Type Reaction
Authors: Malkov Andrei V. , Farn Benjamin P. , Hussain Nigel , Kočovský Pavel
Published: July 2002

The mild, Lewis-acidic complexes [Mo(CO)4Br2]2, (MeCN)2Mo(CO)3(SnCl3)Cl, and (acac)2Mo(OTf)2 have been found to catalyze the C(1)-specific C-glycosylation reaction of glycal acetates 1-3 with silyl enol ethers 4a-4c and electron-rich aromatics 5a, 5b (PhOMe, PhOH). While silyl enol ethers produce predominantly α-C-glycopyranosides (with 2 : 1 to 4 : 1 selectivity), aromatics tend to afford mainly β-C-glycopyranosides (2 : 1 to 3 : 1) in a thermodynamically controlled process.
Mass Fragmentography of Cortisol and Cortisone: Preliminary Studies on the Development of a Reference Method
Authors: Makin Hugh L. J. , Trafford David J. H. , Taylor Norman F.
Published: July 2002

Cortisol and cortisone are the two main glucocorticoids found in human plasma. Cortisol is commonly measured as a means of assessing adrenal function, usually by immunoassay, but such procedures must be subject to proper quality control which ideally uses analyte target values measured by isotope dilution mass fragmentography (GC-MS). Three derivatives of these steroids have been investigated for their chromatographic and mass spectral characteristics in order to develop a simple and rapid GC-MS method for this purpose. Trimethylsilyl ether-O-methyloxime derivatives gave poor sensitivity and thesyn- andanti-isomers were resolved into two peaks. Cyclic methylboronate-O-methyloxime derivatives gave excellent sensitivity but were difficult to prepare, occasionally giving rise, by some unknown mechanism, to 11-oxidation of cortisol. The underivatised 11-hydroxyl of this derivative of cortisol also gave rise to chromatographic problems. Enol-trimethylsilyl ethers however were easy to prepare and gave excellent sensitivity (10-17 times that achieved with the trimethylsilyl ether-O-methyloxime derivatives). Straight line calibration graphs were obtained and the method gave clean traces allowing high specificity and sensitive measurement of cortisol and cortisone in human plasma using tri-deuterated cortisol as an internal standard.
A Brassinosteroid Derivative Useful to Provide More Information About the Importance of the C2 Group in the Brassinosteroid-Receptor Interaction
Authors: Brosa Carme , Amorós Marc , Vázquez Esther , Piqué Maria
Published: July 2002

Synthesis and biological activity evaluation in the rice lamina inclination test of (22R,23R)-22,23-dihydroxy-5α-stigmasta-2,6-dione (6) and its (22S,23S)-diastereoisomer 7 is described. The activity of such compounds is discussed in terms of their ability to form hydrogen bonds by means of GRID maps. The activity elicited by 6 reinforces our idea that an oxygenated function at C3 in a brassinosteroid is more important for biological activity than that at C2. The results also suggest that the 2α-OH of brassinosteroids could act as an acceptor in the putative hydrogen bonding interactions in the brassinosteroid-receptor complex.
Synthesis and Gas Permeability of Block Copolymers Composed of Poly(styrene-co-acrylonitrile) and Polystyrene Blocks
Authors: Lokaj Jan , Brožová Libuše , Holler Petr , Pientka Zbyněk
Published: July 2002

Radical copolymerization of a mixture of styrene (S) and acrylonitrile (AN) at azeotropic composition (63 mole % of S and 37 mole % of AN) at 125 °C in the presence of dibenzoyl peroxide and 2,2,6,6-tetramethylpiperidin-1-yloxyl (TEMPO) gave TEMPO-terminated S-AN copolymers with narrow molecular weight distributions. Both the linear semilogarithmic time-conversion and molecular weight-conversion dependences indicated a quasiliving copolymerization process. Polymerization of styrene initiated with the synthesized macroinitiators containing reversibly bound terminal TEMPO groups yielded film-forming poly(styrene-co-acrylonitrile)-block-polystyrene copolymers. Using the resulting diblock copolymer as a macroinitiator in copolymerization of S and AN, a triblock copolymer of the A-B-A type was obtained. Films of the block copolymers were prepared by casting chloroform solutions and their permeabilities (P) to nitrogen, oxygen, methane, carbon dioxide, and hydrogen were determined. The films showed high selectivities to oxygen (PO2/PN2 > 6). The block copolymers behaved as single-phase homogeneous materials.
An Unusual Transannular Rearrangement of a [2.2]Paracyclophane Derivative to Yield the First [6.2.2]Cyclophane
Authors: Pelter Andrew , Harrison-Marchand Anne , Maxwell Anderson , Mootoo Baldwin , Reid Alicia , Coles Simon J. , Hursthouse Michael B.
Published: July 2002

A unique transannular interaction in the [2.2]paracyclophane series that involves the disruption of an oxazoline on one of the aromatic rings by a ψ-geminal carboxyl group on the adjacent ring is described. The result is the linking of the two benzene rings by the formation of a new interannular ring containing an ester and a secondary amide linkage leading to the first [6.2.2]cyclophane.
Traumatic priapism: an unusual cycling injury: Figure 1
Authors: Golash A , Gray R , Ruttley M S T , Jenkins B J
Published: July 2002

A case is reported of a 35 year old man who sustained an injury to the perineum in a cycling accident which resulted in a traumatic priapism. After confirmation of the diagnosis by Doppler sonography and angiography, therapeutic selective arterial embolisation was followed by successful detumescence of the penis and subsequent return of normal erectile function. It is suggested that percutaneous embolisation of the lacerated cavernosal artery is a safe and effective minimally invasive treatment for this uncommon condition.
The kick with the stick
Authors: Exadaktylos A , Eggli S , Zimmermann H
Published: July 2002

Objective—To investigate the incidence and type of severe microscooter related injuries in adults.

Method—Data were collected between January and September 2000 from the University Hospital Berne, the only referral centre for major trauma in that city, using the software package Qualicare, which connects clinical data with categorised keywords, allowing the immediate localisation of patient groups with defined diagnosis or other clinical information.

Results—Only 0.2% of the patients treated had suffered a microscooter accident. There were five head injuries: three facial lacerations, one fractured mandible, and one cerebral concussion. One patient showed clinical signs of a cervical whiplash injury without radiological findings. There were also two cases of finger laceration and two of muscular contusions of the lower extremities.

Conclusions—Although only a small proportion of the trauma cases were the result of riding microscooters, a system of injury surveillance should be started. Furthermore, protective gear should be worn particularly when microscooters are ridden in the street.
Snow sports injuries in Scotland: a case-control study
Authors: Langran M , Selvaraj S
Published: July 2002

Objectives: To examine the incidence and patterns of snow sports injuries at the three largest commercial ski areas in Scotland and to identify factors associated with injury risk.

Methods: A prospective case-control study of all injured people at Cairngorm, Glenshee, and Nevis Range ski areas during the 1999–2000 winter season. Personal details, snow sports related variables, diagnosis, and treatment were recorded. Control data were collected at random from uninjured people at all three areas. Random counts were performed to analyse the composition of the on slope population.

Results: A total of 732 injuries were recorded in 674 people. Control data were collected from 336 people. The injury rate for the study was 3.7 injuries per 1000 skier days. Alpine skiers comprised 67% of the on slope population, snowboarders 26%, skiboarders 4%, and telemark skiers 2%. Lower limb injuries and sprains were the commonest injuries in alpine skiers and skiboarders. Snowboarders sustained more injuries to the upper limb and axial areas. Skiboarders and snowboarders had a higher incidence of fractures. After adjustment for other variables, three factors were all independently associated with injury: snowboarding (odds ratio (OR) 4.07, 95% confidence interval (CI) 1.65 to 10.08), alpine skiing (OR 3.82, CI 1.6 to 9.13), and age <16 years (OR 1.9, CI 1.14 to 3.17). More than five days of experience in the current season and at least one week of experience in total had a protective effect against injury.

Conclusions: Despite a change in the composition of the alpine population at Scottish ski areas, the overall rate and pattern of injury are similar to those reported previously in comparable studies. Several factors are associated with an increased risk of injury and should be targeted in future injury prevention campaigns.
Ultrasound guided sclerosis of neovessels in painful chronic Achilles tendinosis: pilot study of a new treatment
Authors: Öhberg L , Alfredson H
Published: July 2002

Background:The mechanism that causes pain in chronic Achilles tendinosis is not known. However, high resolution colour Doppler ultrasound has shown that neovascularisation may be involved.

Objective:To investigate if sclerosing the neovessels would affect the level of tendon pain.

Methods:The effect of colour Doppler ultrasound guided injection of a sclerosing agent, polidocanol, against neovessels was studied in 10 patients (seven men and three women, mean age 55 years) with painful chronic mid-portion Achilles tendinosis.

Results:Eight patients were satisfied with the results of treatment. There was significantly reduced pain during activity (reported on a visual analogue scale (VAS)) and no remaining neovascularisation after an average of two injections. Two patients were not satisfied, and neovascularisation remained. At the six month follow up, the same eight patients remained satisfied and could perform Achilles tendon loading activities as desired. Their VAS score had decreased from 74 before treatment to 8 (p<0.01).

Conclusions:Sclerosing neovessels appears to be an effective treatment for painful chronic Achilles tendinosis, suggesting that neovessels play a key part in causing chronic tendon pain.
Rationing and life-saving treatments: should identifiable patients have higher priority?
Authors: Hope Tony
Published: July 2002

Health care systems across the world are unable to afford the best treatment for all patients in all situations. Choices have to be made. One key ethical issue that arises for health authorities is whether the principle of the “rule of rescue” should be adopted or rejected. According to this principle more funding should be available in order to save lives of identifiable, compared with unidentifiable, individuals. Six reasons for giving such priority to identifiable individuals are considered. All are rejected. It is concluded that the principle of the rule of rescue should not be used in determining the allocation of health resources.
Respiratory symptoms and lung function in alumina refinery employees
Authors: Musk A William , de Klerk Nicholas H , Beach Jeremy R , Fritschi Lin , Sim Malcolm R , Benke Geza , Abramson Michael , McNeil John J
Published: July 2002

OBJECTIVES

Employees in alumina refineries are known to be exposed to a number of potential respiratory irritants, particularly caustic mist and bauxite and alumina dusts. To examine the prevalence of work related respiratory symptoms and lung function in alumina refinery employees and relate these to their jobs.

METHODS

2964 current employees of three alumina refineries in Western Australia were invited to participate in a cross sectional study, and 89% responded. Subjects were given a questionnaire on respiratory symptoms, smoking, and occupations with additional questions on temporal relations between respiratory symptoms and work. Forced expiratory volume in 1 second (FEV1) and forced vital capacity (FVC) were measured with a rolling seal spirometer. Atopy was assessed with prick skin tests for common allergens. Associations between work and symptoms were assessed with Cox's regression to estimate prevalence ratios, and between work and lung function with linear regression.

RESULTS

Work related wheeze, chest tightness, shortness of breath, and rhinitis were reported by 5.0%, 3.5%, 2.5%, and 9.5% of participants respectively. After adjustment for age, smoking, and atopy, most groups of production employees reported a greater prevalence of work related symptoms than did office employees. After adjustment for age, smoking, height, and atopy, subjects reporting work related wheeze, chest tightness, and shortness of breath had significantly lower mean levels of FEV1(186, 162, and 272 ml respectively) than subjects without these symptoms. Prevalence of most work related symptoms was higher at refinery 2 than at the other two refineries, but subjects at this refinery had an adjusted mean FEV1>60 ml higher than the others. Significant differences in FVC and FEV1/FVC ratio, but not FEV1, were found between different process groups.

CONCLUSIONS

There were significant differences in work related symptoms and lung function between process groups and refineries, but these were mostly not consistent. Undefined selection factors and underlying population differences may account for some of these findings but workplace exposures may also contribute. The differences identified between groups were unlikely to be clinically of note.
Mortality from lung cancer among silicotic patients in Sardinia: an update study with 10 more years of follow up
Authors: Carta P , Aru G , Manca P
Published: July 2002

OBJECTIVES

To evaluate the association between silica, silicosis and lung cancer, the mortality of 724 patients with silicosis, first diagnosed by standard chestxray film between 1964 and 1970, has been analysed by a cohort study extended to 31 December 1997.

METHODS

Smoking and detailed occupational histories were available for each member of the cohort as well as the estimated lifetime exposure to respirable silica dust and radon daughters. Two independent readers blindly classified standard radiographs according to the 12 point International Labour Organisation (ILO) scale. Lung function tests meeting the American Thoracic Society's criteria were available for 665 patients. Standardised mortality ratios (SMRs) for selected causes of death were based on the age specific Sardinian regional death rates.

RESULTS

The mortality for all causes was significantly higher than expected (SMR 1.35, 95% confidence interval (95% CI) 1.24 to 1.46) mainly due to tuberculosis (SMR 22.0) and to non-malignant chronic respiratory diseases (NMCRD) (SMR 6.03). All cancer deaths were within the expected numbers (SMR 0.93; 95% CI 0.76 to 1.14). The SMR for lung cancer was 1.37 (95% CI 0.98 to 1.91, 34 observed), increasing to 1.65 (95% CI 0.98 to 2.77) allowing for 20 years of latency since the first diagnosis of silicosis. Although mortality from NMCRD was strongly associated to the severity of radiological silicosis and to the extent of the cumulative exposure to silica, SMR for lung cancer was weakly related to the ILO categories and to the cumulative exposure to silica dust only after 20 years of lag interval. A significant excess of deaths from lung cancer (SMR 2.35) was found among silicotic patients previously employed in underground metal mines characterised by a relatively high airborne concentration of radon daughters and among ever smokers who showed an airflow obstruction at the time of the first diagnosis of silicosis (SMR 3.29). Mortality for lung cancer related to exposure was evaluated with both the Cox's proportional hazards modelling within the entire cohort and a nested case-control study (34 cases of lung cancer and 136 matched controls). Both multivariate analyses did not show any significant association with cumulative exposure to silica or severity of silicosis, but confirmed the association between mortality for lung cancer and relatively high exposure to radon, smoking, and airflow obstruction as significant covariates.

CONCLUSIONS

The findings indicate that the slightly increased mortality for lung cancer in this cohort of silicotic patients was significantly associated with other risk factors—such as cigarette smoking, airflow obstruction, and estimated exposure to radon daughters in underground mines—rather than to the severity of radiological silicosis or to the cumulative exposure to crystalline silica dust itself.
Evaluation of amlodipine, lisinopril, and a combination in the treatment of essential hypertension
Authors: Naidu M U R , Usha P R , Rao T Ramesh Kumar , Shobha J C
Published: July 2002

Angiotensin converting enzyme (ACE) inhibitors and dihydropyridine calcium antagonists are well established and widely used as monotherapy in patients with mild to moderate essential hypertension. Earlier studies combining short acting drugs from these classes require multiple dosing and were associated with poor compliance. Availability of longer acting compounds allows once daily administration to avoid the inconvenience of a multiple daily dose. It was decided to perform a randomised double blind, crossover study with the long acting calcium channel blocker amlodipine and the long acting ACE inhibitor lisinopril, given either alone or in combination in essential hypertension. Twenty four patients with diastolic blood pressure (DBP) between 95 and 104 mm Hg received amlodipine 2.5 mg and 5 mg, lisinopril 5 mg and 10 mg, and their combination as per a prior randomisation schedule. Supine and standing blood pressure and heart rate were recorded at weekly intervals. Higher doses of both the drugs individually or in combination were used if the target supine DBP below 90 mm Hg was not achieved. There was a significant additional blood pressure lowering effect with the combination when compared either with amlodipine or lisinopril alone. Five mg amlodipine and 10 mg lisinopril monotherapy achieved the target blood pressure in 71% and 72% patients respectively. The combination of 2.5 mg amlodipine with 5 mg lisinopril produced a much more significant lowering of blood pressure in a higher percentage of patients than that with an individual low dose.
Survey of hospital doctors' attitudes and knowledge of oral conditions in older patients
Authors: Morgan R , Tsang J , Harrington N , Fook L
Published: July 2002

The study was designed to assess the views and knowledge of hospital doctors in general and geriatric medicine on oral health in older people. Eighty two doctors in general and geriatric medicine at two hospitals were shown 12 colour slides of oral mucosal conditions and asked to give a diagnosis for each slide and complete a questionnaire. Completed questionnaires with the answers to the coloured slides were returned completed by 70 doctors.

The majority of doctors (84%) felt it was important to examine older patients' mouths, however only 19% (χ2 p=0.0001) routinely do so. If asked to prescribe nystatin by the nursing staff, 30% said they would do so without examining the mouth itself. Only 9% of doctors knew that wearing dentures was a specific risk factor for oral candidiasis (χ2 p=0.001). Altogether 56% of doctors did not feel confident in examining the oral cavity and most (77%) did not think they had had sufficient training in this examination. Only two doctors correctly diagnosed all of the slides. An early squamous carcinoma was misdiagnosed by 80% of the doctors (χ2p=0.0001).

Hospital doctors do not routinely inspect older patients' mouths. Even if shown slides of typical oral mucosal lesions many hospital doctors are unable to diagnose them. Issues on training need to be addressed. From the patients' point of view a public health campaign is required to educate older people on the need for a regular dental review and be aware that doctors may not be able to diagnose serious oral conditions. Key pointsFew hospital doctors routinely examine older patients' mouths.Few hospital doctors feel they have had sufficient training in examining the oral cavity.When shown textbook slides of oral conditions few doctors can accurately diagnose them.
Phosphorus solubilization and pH changes as a result of the interactions between soil bacteria and arbuscular mycorrhizal fungi on a medium containing NO3-as nitrogen source
Authors: Villegas J , Fortin J A
Published: July 2002

The interactions between arbuscular mycorrhizal fungi and bacteria may affect the nutrient dynamics in the environment. To study these changes, assays were conducted in a two-compartment Petri plate system. A NO3--N medium containing an insoluble phosphate (P) source was used to evaluate the effect of Glomus intraradices (Schenck & Smith) external mycelium, mycorrhizal, and nonmycorrhizal transformed carrot roots (Daucus carrota L.), alone or in interaction with Pseudomonas aeruginosa (Schroeter) Migula, Pseudomonas putida (Trevisan) Migula, or Serratia plymuthica (Dyar) Bergey et al., on phosphorus solubilization and pH changes of the medium. In the NO3--containing medium, G. intraradices external mycelium as well as the three bacterial species studied were rather inefficient P solubilizers when growing individually. However, when G. intraradices external mycelium interacted with either P. aeruginosa or P. putida, the levels of soluble P in the medium significantly increased (P [Formula: see text] 0.05). These improvements were closely related to changes in the pH of the medium.Key words: Glomus intraradices, P solubilization, external mycelium, Pseudomonas aeruginosa, Pseudomonas putida, Serratia plymuthica.
Tributary-specific variation in timing of return of adult Atlantic salmon (Salmo salar) to fresh water has a genetic component
Authors: Stewart David C , Smith Gordon W , Youngson Alan F
Published: July 2002

Variation in the timing of return of adult Atlantic salmon (Salmo salar) to rivers contributes diversity to salmon fisheries and is therefore an important effect on their economic value. In this paper, we test two sequential null hypotheses: (i) that run timing does not vary among populations from different tributaries and (ii) that differences in time of return between populations from different tributaries are not evident following transfer to a common location. Adult fish originating from two tributaries of the River Tay, the Almond and Tummel, were caught in local fisheries on different dates. For both tributaries, run timing in two-sea-winter (2SW) fish was earlier than for one-sea-winter (1SW) fish. Within both sea-age classes, recaptures of Tummel fish preceded those from the Almond. After the progeny of Almond and Tummel fish were transferred to a third tributary of the River Tay, the Braan, differences in run timing between the tributary groups were identified for both sea-age classes. The differences were highly consistent with those present in fish that had reared in their native tributaries, indicating a strong heritable component for the run timing trait. Tributary-specific differences in run timing have important implications for the management of seasonally complex fisheries.
Identification and chromosomal organization of two rye genome-specific RAPD products useful as introgression markers in wheat
Authors: Ko Jong-Min , Do Geum-Sook , Suh Duck-Yong , Seo Bong-Bo , Shin Doo-Chull , Moon Huhn-Pal
Published: July 2002

Two rye genome-specific random amplified polymorphic DNA (RAPD) markers were identified for detection of rye introgression in wheat. Both markers were amplified in all of the tested materials that contained rye chromatin such as rye, hexaploid triticale, wheatrye addition lines, and wheat varieties with 1BL.1RS translocation. Two cloned markers, designated pSc10C and pSc20H, were 1012 bp and 1494 bp, respectively. Sequence analysis showed that both pSc10C and pSc20H fragments were related to retrotransposons, ubiquitously distributed in plant genomes. Using fluorescence in situ hybridization (FISH), probe pSc10C was shown to hybridize predominantly to the pericentromeric regions of all rye chromosomes, whereas probe pSc20H was dispersed throughout the rye genome except at telomeric regions and nucleolar organizing regions. The FISH patterns showed that the two markers should be useful to select or track all wheatrye translocation lines derived from the whole arms of rye chromosomes, as well as to characterize the positions of the translocation breakpoints generated in the proximal and distal regions of rye arms.Key words: RAPD, FISH, Secale cereale, Triticum aestivum, genome-specific sequences.
Removal of aqueous phenol by Arthromyces ramosus peroxidase
Authors: Villalobos D A , Buchanan I D
Published: July 2002

The removal of aqueous phenol by Arthromyces ramosus peroxidase (ARP), in the presence of high molecular weight polyethylene glycol (PEG) as a protective additive, was investigated to study (i) the stoichiometry between phenol removal and peroxide consumption, (ii) enzyme inactivation in the presence of excess hydrogen peroxide, and (iii) the effect of reactor operating mode on phenol removal. The stoichiometry was observed to increase with increasing phenol conversion, and reached a maximum value of 0.9 mol phenol/mol peroxide when nearly complete phenol conversion was achieved. Spectral scans indicated that P-670 did not form with ARP in the presence of high concentrations of peroxide and in the absence of a reducing substrate. As long as phenol concentration was not limiting, the turnover capacity varied by approximately 3% of its average value of 76 400. This indicates that only marginal improvement in the efficiency of enzyme use would be achieved by stepped addition of enzyme. Similarly, sequential addition of hydrogen peroxide over an extended period of time yielded only a slight improvement in phenol removal from the reaction mixture. Key words: Arthromyces ramosus peroxidase, enzyme inactivation, phenol removal, reactor operation, stoichiometry.