bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of β2‐agonist treatment and spirometry on exhaled nitric oxide in healthy children and children with asthma
Authors: Kissoon Niranjan , Duckworth Laurie J. , Blake Kathryn V. , Murphy Suzanne P. , Lima John J. 
Published: October 2002

AbstractWe set out to determine the effect of spirometry and bronchodilator therapy on exhaled nitric oxide (FENO) values in children. We hypothesized that there will be no difference on FENO values pre‐ and postspirometry and following bronchodilator therapy. Sixteen children [(mean = 14.4 ± 1.2 years; range, 12–18 years; healthy controls (n = 6); asthmatics on inhaled steroids (n = 5); and asthmatics on no steroids (n = 5)] had exhaled nitric oxide (FENO) measurements on 4 consecutive days as follows: pre‐ and postspirometry (day 1); pre‐ and postalbuterol metered dose inhaler (MDI) therapy (day 2); pre‐ and postspirometry and albuterol MDI therapy (day 3); and pre‐ and postspirometry and placebo MDI (day 4). FENO was measured with a chemiluminescence analyzer, using the single vital capacity exhalation technique at an exhalation flow of 50 mL/sec.There were no statistically significant differences in FENO values pre‐ and poststudy maneuvers under all experimental conditions in healthy children. However, in healthy children, clinically relevant (>10%) differences from baseline were observed on day 1 (3–18 min) and day 4 at 18 min. In children with asthma, FENO values increased significantly by 11–19% from pretreatment levels at 8 and 18 min, postbronchodilator on day 2, and 12–17% at 8 and 18 min post bronchodilator and spirometry on day 3. Spirometry and treatment with a placebo (day 4) resulted in a decrease in FENO values by 11% at 3 min postbaseline in patients on inhaled steroids. The changes observed were similar in children on vs. off inhaled steroids, and also in well‐controlled vs. poorly controlled asthma.We conclude that FENO values should be obtained consistently either pre‐ and at a specific time postalbuterol treatment or spirometry. Alternatively, changes in FENO values should be interpreted in relationship to the timing of these maneuvers. Pediatr Pulmonol. 2002; 34:203–208. © 2002 Wiley‐Liss, Inc.
Inhibition of proliferation of PC‐3 human prostate cancer by antagonists of growth hormone–releasing hormone: Lack of correlation with the levels of serum IGF‐I and expression of tumoral IGF‐II and vascular endothelial growth factor
Authors: Plonowski Artur , Schally Andrew V. , Letsch Markus , Krupa Magdalena , Hebert Francine , Busto Rebeca , Groot Kate , Varga Jozsef L. 
Published: October 2002

AbstractBACKGROUNDAntagonists of growth hormone–releasing hormone (GHRH) such as JV‐1‐38 can inhibit androgen‐independent prostate cancer directly by several mechanisms and/or indirectly by suppressing growth hormone/insulin‐like growth factor‐I (GH/IGF‐I) axis. To shed more light on the mechanisms involved, the effects of JV‐1‐38 on PC‐3 human prostate cancer were compared with those of somatostatin analog RC‐160 in vivo and in vitro.METHODSNude mice bearing PC‐3 tumors received JV‐1‐38 (20 μg), RC‐160 (50 μg) or a combination of JV‐1‐38 and RC‐160. The concentration of IGF‐I in serum and the expression of mRNA for IGF‐II and vascular endothelial growth factor (VEGF) in tumor tissue were investigated.RESULTSIn vivo, the final volume of PC‐3 tumors treated with JV‐1‐38 was significantly lowered by 49% (P < 0.01), whereas RC‐160 exerted only 30% inhibition (NS), compared with controls. Combined use of both compounds augmented tumor inhibition to 63% (P < 0.001). Serum IGF‐I levels were decreased only in mice treated with RC‐160. JV‐1‐38 suppressed mRNA for IGF‐II in PC‐3 tumors by 42%, whereas RC‐160 alone or in combination with JV‐1‐38 caused a 65% reduction. JV‐1‐38 and RC‐160 used as single drugs decreased the expression of VEGF by 50%, and their combination caused a 63% reduction. In vitro, JV‐1‐38 inhibited the proliferation of PC‐3 cells by 39%. This effect could be partially reversed by addition of IGF‐I to the serum‐free medium. RC‐160 alone did not affect the PC‐3 cell growth in vitro, but in combination with JV‐1‐38 it augmented the antiproliferative effect of the GH‐RH antagonist to 72%. Exposure to JV‐1‐38 in vitro reduced the expression of mRNA for IGF‐II in PC‐3 cells by 55% but did not change VEGF mRNA levels, whereas RC‐160 had no effect.CONCLUSIONSThe antiproliferative effect of JV‐1‐38 was not associated with the suppression of serum IGF‐I and was only partially correlated with the expression of IGF‐II and VEGF in PC‐3 tumors, suggesting that other mechanisms play a role in the antitumor action of GHRH antagonists. Nevertheless, the stronger inhibition of tumor growth after combined treatment with JV‐1‐38 and RC‐160 indicates that the interference with multiple local stimulatory factors leads to an enhanced inhibition of prostate cancer. Prostate 52:173–182, 2002. © 2002 Wiley‐Liss, Inc.
Signal transduction in the photoactive yellow protein. I. Photon absorption and the isomerization of the chromophore
Authors: Groenhof Gerrit , Lensink Marc F. , Berendsen Herman J. C. , Snijders Jaap G. , Mark Alan E. 
Published: October 2002

AbstractMolecular dynamics simulation techniques together with time‐dependent density functional theory calculations have been used to investigate the effect of photon absorption by a 4‐hydroxy‐cinnamic acid chromophore on the structural properties of the photoactive yellow protein (PYP) from Ectothiorodospira halophila. The calculations suggest that the protein not only modifies the absorption spectrum of the chromophore but also regulates the subsequent isomerization of the chromophore by stabilizing the isomerization transition state. Although signaling from PYP is thought to involve partial unfolding of the protein, the mechanical effects accompanying isomerization do not appear to directly destabilize the protein. Proteins 2002;48:202–211. © 2002 Wiley‐Liss, Inc.
Stability of macromolecular complexes
Authors: Brooijmans Natasja , Sharp Kim A. , Kuntz Irwin D. 
Published: October 2002

AbstractMacromolecular interactions are crucial in numerous biologic processes, yet few general principles are available that establish firm expectations for the strength of these interactions or the expected contribution of specific forces. The simplest principle would be a monotonic increase in interactions as the size of the interface grows. The exact relationship might be linear or nonlinear depending on the nature of the forces involved. Simple “linear–free energy” relationships based on atomic properties have been well documented, for example, additivity for the interaction of small molecules with solvent, and, recently, have been explored for ligand–receptor interactions. Horton and Lewis propose such additivity based on buried surface area for protein–protein complexes. We investigated macromolecular interactions and found that the highest‐affinity complexes do not fulfill this simple expectation. Instead, binding free energies of the tightest macromolecular complexes are roughly constant, independent of interface size, with the notable exception of DNA duplexes. By comparing these results to an earlier study of protein–ligand interactions we find that: (1) The maximum affinity is approximately 1.5 kcal/mol per nonhydrogen atom or 120 cal/mol Å2 of buried surface area, comparable to results of our earlier work; (2) the lack of an increase in affinity with interface size is likely due to nonthermodynamic factors, such as functional and evolutionary constraints rather than some fundamental physical limitation. The implication of these results have some importance for molecular design because they suggest that: (1) The stability of any given complex can be increased significantly if desired; (2) small molecule inhibitors of macromolecular interactions are feasible; and (3) different functional classes of protein–protein complexes exhibit differences in maximal stability, perhaps in response to differing evolutionary pressures. These results are consistent with the widespread observation that proteins have not evolved to maximize thermodynamic stability, but are only marginally stable. Proteins 2002;48:645–653. © 2002 Wiley‐Liss, Inc.
Monte Carlo simulations of the peptide recognition at the consensus binding site of the constant fragment of human immunoglobulin G: The energy landscape analysis of a hot spot at the intermolecular interface
Authors: Verkhivker Gennady M. , Bouzida Djamal , Gehlhaar Daniel K. , Rejto Paul A. , Freer Stephan T. , Rose Peter W. 
Published: October 2002

AbstractMonte Carlo simulations of molecular recognition at the consensus binding site of the constant fragment (Fc) of human immunoglobulin G (Ig) protein have been performed to analyze structural and thermodynamic aspects of binding for the 13‐residue cyclic peptide DCAWHLGELVWCT. The energy landscape analysis of a hot spot at the intermolecular interface using alanine scanning and equilibrium‐simulated tempering dynamics with the simplified, knowledge‐based energy function has enabled the role of the protein hot spot residues in providing the thermodynamic stability of the native structure to be determined. We have found that hydrophobic interactions between the peptide and the Met‐252, Ile‐253, His‐433, and His‐435 protein residues are critical to guarantee the thermodynamic stability of the crystallographic binding mode of the complex. Binding free energy calculations, using a molecular mechanics force field and a solvation energy model, combined with alanine scanning have been conducted to determine the energetic contribution of the protein hot spot residues in binding affinity. The conserved Asn‐434, Ser‐254, and Tyr‐436 protein residues contribute significantly to the binding affinity of the peptide–protein complex, serving as an energetic hot spot at the intermolecular interface. The results suggest that evolutionary conserved hot spot protein residues at the intermolecular interface may be partitioned in fulfilling thermodynamic stability of the native binding mode and contributing to the binding affinity of the complex. Proteins 2002;48:539–557. © 2002 Wiley‐Liss, Inc.
Design and folding of dimeric proteins
Authors: Tiana Guido , Broglia Ricardo A. 
Published: October 2002

AbstractIn a similar way in which the folding of single‐domain proteins provides an important test in the study of self‐organization, the folding of homodimers constitutes a basic challenge in the quest for the mechanisms that are the basis of biological recognition. Dimerization is studied by following the evolution of two identical 20‐letter amino acid chains within the framework of a lattice model and using Monte Carlo simulations. It is found that when design (evolution pressure) selects few, strongly interacting (conserved) amino acids to control the process, a three‐state folding scenario follows, where the monomers first fold forming the halves of the eventual dimeric interface independently of each other, and then dimerize (“lock and key” kind of association). On the other hand, if design distributes the control of the folding process on a large number of (conserved) amino acids, a two‐state folding scenario ensues, where dimerization takes place at the beginning of the process, resulting in an “induced type” of association. Making use of conservation patterns of families of analogous dimers, it is possible to compare the model predictions with the behavior of real proteins. It is found that theory provides an overall account of the experimental findings. Proteins 2002;49:82–94. © 2002 Wiley‐Liss, Inc.
Herbicide loss following application to a roadside
Authors: Ramwell Carmel T , Heather Andrew I J , Shepherd Anthony J 
Published: October 2002

AbstractRisk assessments for herbicides applied to roads are limited by the lack of knowledge on the fate and behaviour of the compounds in the urban environment. This study was designed to address this deficiency by quantifying the percentage loss of six herbicides following application to a roadside. Herbicides were applied on two occasions to a 16‐m length of roadside and kerb edge. An automatic water sampler was used to collect run‐off, draining to a single gulley pot, until 25 mm of rain had fallen. Samples were analysed for glyphosate, atrazine, diuron, oxadiazon and oryzalin, and peak concentrations were 650, 2210, 1810, 390 and 70 µg litre−1 respectively. Isoxaben was also applied, but concentrations in run‐off were below the limit of detection (10 µg litre−1). Herbicide concentrations all followed a similar pattern of rapid decline throughout the first rain event following application, with the majority of loss occurring within the first 10 mm of accumulated rainfall, but compounds of high solubility and low Koc produced the highest peak concentrations. For those compounds of relatively low solubility and moderate Koc, application rate may be an influential factor in determining herbicide loss for these compounds. The percentage loss of the active substances applied differed between compounds, ranging from <10% to 73%. The ecotoxicological significance of the results is discussed.© 2002 Society of Chemical Industry
The strobilurin fungicides
Authors: Bartlett Dave W , Clough John M , Godwin Jeremy R , Hall Alison A , Hamer Mick , Parr‐Dobrzanski Bob 
Published: October 2002

AbstractStrobilurins are one of the most important classes of agricultural fungicide. Their invention was inspired by a group of fungicidally active natural products. The outstanding benefits they deliver are currently being utilised in a wide range of crops throughout the world. First launched in 1996, the strobilurins now include the world's biggest selling fungicide, azoxystrobin. By 2002 there will be six strobilurin active ingredients commercially available for agricultural use. This review describes in detail the properties of these active ingredients – their synthesis, biochemical mode of action, biokinetics, fungicidal activity, yield and quality benefits, resistance risk and human and environmental safety. It also describes the clear technical differences that exist between these active ingredients, particularly in the areas of fungicidal activity and biokinetics.© 2002 Society of Chemical Industry
Effects of Melilotus officinalis on acute inflammation
Authors: Pleşca‐Manea Luminiţa , Pârvu Alina Elena , Pârvu M. , Taaˇmaş M. , Buia R. , Puia M. 
Published: October 2002

AbstractOur study investigated the effects of Melilotus officinalis L. extract, containing 0.25% coumarin, on acute inflammation induced with oil of turpentine in male rabbits. The results were compared with those from a group treated with hydrocortisone sodium hemisuccinate and one injected with coumarin before inflammation was induced. The effects were evaluated by measuring serum citrulline, a test of in vitro phagocytosis, total leukocyte count and differential leukocyte count expressed as a percentage. M. officinalis had antiinflammatory effects because it reduced the activation of circulating phagocytes and lowered citrulline production. These properties were similar to those of hydrocortisone sodium hemisuccinate and coumarin. In the bone marrow acute phase response, M. officinalis had an inhibitory action that was lower than that of hydrocortisone sodium hemisuccinate and similar to coumarin. Copyright © 2002 John Wiley & Sons, Ltd.
Effect of saikosaponin‐A, a triterpenoid glycoside, isolated from Bupleurum falcatum on experimental allergic asthma
Authors: Park Kwan Ha , Park Jongmin , Koh Dongsoo , Lim Yoongho 
Published: October 2002

AbstractThe separation and isolation of an extract of Bupleurum falcatum were performed based on antiallergic activities in preliminary studies with higher plants. The final active compound was identified as saikosaponin‐A (SSA), a triterpenoid glycoside. SSA at more than 1 mg/kg (i.v.) significantly inhibited the passive cutaneous anaphylaxis reaction in rats in a dose‐dependent manner, attaining a maximum inhibition of approximately 60% with 10 mg/kg. SSA at 3 and 10 mg/kg also suppressed asthmatic bronchoconstriction in sensitized guinea‐pigs. SSA possesses a weak inhibitory activity on histamine‐induced tracheal contraction in guinea‐pigs and on histamine release induced by A‐23187 in rat mast cells. These results indicate that SSA has an inhibitory activity against allergic asthma. This activity seems to derive from both antagonism of the histamine action and inhibition of allergic mediators. Additional mechanisms may also be involved. Copyright © 2002 John Wiley & Sons, Ltd.
Globularia alypum L. extracts reduced histamine and serotonin contraction in vitro
Authors: Bello Regina , Moreno Lucrecia , Primo‐Yúfera Eduardo , Esplugues Juan 
Published: October 2002

AbstractThe present study analyses in in vitro models the pharmacological activity of methanol and dichloromethane extracts (1, 10 and 100 μg/mL) obtained from the leaves and stems of Globularia alypum L. Preincubation of the guinea‐pig ileum and rat uterus with both extracts produced a dose dependent abolition of the contractile effects of histamine and serotonin, respectively. At the same doses, neither methanol nor dichloromethane extract reduced the contractile effects of acetylcholine on rat duodenum or noradrenaline on rat vas deferens. Copyright © 2002 John Wiley & Sons, Ltd.
Inhibition of cholesterol biosynthesis in HepG2 cells by artichoke extracts is reinforced by glucosidase pretreatment
Authors: Gebhardt Rolf 
Published: October 2002

AbstractHigh‐dose aqueous extracts from artichoke leaves were found to inhibit cholesterol biosynthesis from 14C‐acetate rather moderately in HepG2 cells in contrast to primary cultured rat hepatocytes in which the inhibition was stronger. Preincubation of the extracts with several glycohydrolases revealed that pretreatment with β‐glucosidase considerably reinforced the inhibition. A significant reduction of acetate incorporation was found above extract concentrations of 0.01 mg/mL and at 0.2 mg/mL almost 60% inhibition was observed. Cytotoxic effects detected by the MTT‐assay were restricted to higher concentrations of the extracts with and without β‐glucosidase pretreatment. Since cynaroside represents a major glucoside in artichoke extracts, both cynaroside and its aglycone luteolin were tested. It could be demonstrated that cynaroside is indeed one of the targets of β‐glucosidase and that the liberated luteolin is responsible for the inhibitory effect. Direct measurements of β‐glucosidase activity in rat hepatocytes and HepG2 cells revealed that endogenous enzyme activity in hepatocytes may be sufficient to convert cynaroside to its aglycone, while in HepG2 cells this may not be the case. These findings emphasize the importance of β‐glucosidase‐dependent liberation of luteolin for the ability of artichoke extracts to inhibit hepatic cholesterol biosynthesis. Copyright © 2002 John Wiley & Sons, Ltd.
Influence of co‐monomer structure on properties of co‐polyamide packaging films
Authors: Scarfato P. , Di Maio L. , Incarnato L. , Acierno D. , Mariano A. 
Published: October 2002

AbstractIn this work a series of co‐polyamides were prepared by random polymerization of ϵ‐caprolactam in presence of four different co‐monomers at a percentage of 5% w/w, with the aim of verifying their suitability as film‐forming materials. The effects of structural changes induced in the ϵ‐caprolactam homopolymer by co‐monomers were evaluated in both molten and solid states. Rheological tests in shear and elongational flow were performed to evaluate the processability of co‐polyamides. Cast films were obtained and their thermal, mechanical and transport properties were evaluated to establish the performances of the co‐polyamides in view of packaging applications. The results indicate that co‐polyamide films having a partially aromatic structure display the best mechanical performances and show a significant improvement in barrier properties to gases compared to the homopolymer. Copyright © 2002 John Wiley & Sons, Ltd.
Comparison of flat film to total package water vapour transmission rates for several commercial food wraps
Authors: Steven Matthew D. , Hotchkiss Joseph H. 
Published: October 2002

AbstractThe barrier properties of a package are the sum of material and seal permeations. Although addressed for hermetically sealed and modified atmosphere packages, little consideration of total package permeation has been given to commercial food wraps. Standard protocols were used to compare the water vapour transmission rates (WVTRs) of materials and packages for seven commercial food wraps: aluminum foil; poly(vinylidene chloride) (PVdC) film; three poly(ethylene) (PE) films; an adhesive‐modified PE film; and plasticized poly(vinyl chloride) (PVC) film. Water ingress for a complete package was compared to calculated material permeation based on film WVTRs. Film‐to‐glass adhesion strength was also measured. Model systems (desiccant) were compared to foods at ambient and refrigeration temperatures. Aluminum foil had the lowest material WVTR (0.10 g/h/m2), closely followed by PVdC (0.13 g/h/m2). These WVTRs were approximately five‐fold lower than the PEs (∼0.65 g/h/m2), which were nearly 10‐fold lower than PVC (4.9 g/h/m2). The adhesive‐modified PE film had the lowest difference between material and package transmission rates (0.7 E‐03 g/h), approximately half that of the PVdC film (1.1 E‐03 g/h), which was significantly lower than the remaining films (2.3 E‐03 –3.9 E‐03 g/h). The adhesive PE film had the strongest film–glass adhesion. Ambient food product test results were similar to model system (desiccant) results, but refrigerated trials showed significantly different relative package transmission rates. This was attributed to the reduced adhesion of most wraps at refrigeration temperatures. Copyright © 2002 John Wiley & Sons, Ltd.
Theoretical quantum chemical study of benzoic acid: Geometrical parameters and vibrational wavenumbers
Authors: Palafox M. Alcolea , Núñez J. L. , Gil M. 
Published: October 2002

AbstractThe structure of benzoic acid as monomer was studied by semiempirical, ab initio, and density functional methods using several basis sets. The performance of these methods in calculating and describing the vibrational frequencies of benzoic acid and several derivatives was determined. The cyclic dimer form of benzoic acid was also reproduced. Two new procedures of scaling the frequencies were presented. For the ring modes, specific scale equations and scale factors were used from benzene molecule. For the carboxylic group, scaling equations and specific scale factors at different levels were also determined to be used in benzoic acid derivatives. A reassignment of several bands was done. A comparison of the cost/effective method and procedure of scaling was carried out. A significant reduction of the error in the predicted frequencies was obtained over the one‐factor standard scaling procedure. © 2002 Wiley Periodicals, Inc. Int J Quantum Chem, 2002