bluuebunny/crossref_metadata_2025 huggingface dataset:
Comments on Hilbert curve fractal antenna: A small resonant antenna for VHF/UHF applications
Authors: Best Steven R.
Published: October 2002

© 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 35: 420–421, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10625
Authors' reply to “comments on Hilbert curve fractal antenna: A small resonant antenna for VHF/UHF applications”
Authors: Vinoy K. J. , Varadan V. K.
Published: October 2002

© 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 35: 421, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10626
Inhibition of maximal voluntary contraction force by experimental muscle pain: A centrally mediated mechanism
Authors: Graven‐Nielsen Thomas , Lund Hans , Arendt‐Nielsen Lars , Danneskiold‐Samsøe Bente , Bliddal Henning
Published: October 2002

Muscle weakness frequently accompanies conditions with musculoskeletal pain. It is not clear if this attenuation of force is due to peripheral or central processes. The effect of experimental muscle pain on maximal voluntary contraction torque and peripheral contractile properties was therefore assessed. Experimental muscle pain reduced the torque produced by isometric knee extension, but the contractile properties assessed by twitch interpolation were not affected. This indicates that force inhibition by muscle pain is centrally mediated. This has clinical implications for rehabilitation and training of patients with musculoskeletal pain. © 2002 Wiley‐Liss, Inc. Muscle Nerve 26: 708–712, 2002
Anomalous superficial radial nerve: A patient with probable autosomal dominant inheritance of the anomaly
Authors: Kuruvilla Abraham , Laaksonen Satu , Falck Björn
Published: October 2002

The sensory symptoms due to lesions of the superficial branch of the radial nerve are usually limited to the dorsolateral area of the hand. We describe a 40‐year‐old woman who presented with numbness of the dorsomedial aspect of the right hand following arthroplasty of the wrist. Clinically, the sensory loss suggested a lesion of the dorsal branch of the ulnar nerve. However, nerve conduction studies showed that the sensory loss was due to a lesion of a branch of the superficial branch of the radial nerve. The patient had bilateral, anomalous innervation of the dorsum of the hand—the dorsal branch of the ulnar nerve could not be demonstrated with nerve conduction techniques and the superficial branch of the radial nerve innervated most of the dorsum of the hand. Antidromic stimulation of the dorsal branch of the ulnar nerve and superficial branch of the radial nerve with paired surface recording of sensory nerve action potentials from the dorsolateral (radial side) and dorsomedial (ulnar side) hand is useful for evaluating this anomaly. Our patient had two children, one of them with a similar anomaly. This suggests an autosomal dominant inheritance of the anomaly. © 2002 Wiley Periodicals, Inc. Muscle Nerve 26: 716–719, 2002
Motion of the foot and ankle during the stance phase in rats
Authors: Varejão Artur S. P. , Cabrita António M. , Meek Marcel F. , Bulas‐Cruz José , Gabriel Ronaldo C. , Filipe Vitor M. , Melo‐Pinto Pedro , Winter David A.
Published: October 2002

Computerized analysis of rat gait is becoming an invaluable technique used by some peripheral nerve investigators for the evaluation of function. In this article we describe the use of a biomechanical model of the foot and ankle that allows a quantitative assessment and description of the ankle angle, reflecting plantarflexion and dorsiflexion during the stance phase of gait. Kinematic data of 144 trial walks from 36 normal rats were recorded with a high‐speed digital image camera at 225 images per second. The ankle angular changes associated with the specific temporal events of foot placement on the ground through the stance phase were assessed. The information obtained was used to propose a new subdivision of the stance phase in the rat into three major components. This approach will provide a helpful research tool to analyze gait data that rely on the accurate determination of spatiotemporal foot events. © 2002 Wiley Periodicals, Inc. Muscle Nerve 26: 630–635, 2002
Skeletal muscle fiber function and rate of disease progression in amyotrophic lateral sclerosis
Authors: Krivickas Lisa S. , Yang Jung‐In , Kim Sang‐Kyu , Frontera Walter R.
Published: October 2002

The contractile properties of single muscle fibers reflect the functional status of muscle at the cellular level and have not been described in amyotrophic lateral sclerosis (ALS). Chemically skinned single muscle fibers (n = 173), obtained by needle biopsy from six men with ALS, were activated with Ca2+, allowing maximal force measurements and specific force (SF) estimates. Maximum unloaded shortening velocity (Vo) was determined using the slack test. The results were compared with muscle from healthy controls. Markers of disease progression included rate of change of ALS functional rating scale score, rate of change of forced vital capacity, and disease duration. Compared with controls, ALS patients had decreased whole muscle SF (measured by a combination of computerized tomography and isokinetic testing) but normal single fiber SF. The Vo was greater for type I fibers in ALS. Patients with slower disease progression had increased single fiber size and a high percentage of hybrid fibers (expressing multiple myosin heavy chain isoforms). A needle biopsy obtained at the time of ALS diagnosis may assist with predicting rate of disease progression. © 2002 Wiley Periodicals, Inc. Muscle Nerve 26: 636–643, 2002
Near‐nerve needle sensory conduction study of the medial calcaneal nerve: New method and report of four cases of medial calcaneal neuropathy
Authors: Seo Jeong‐Hwan , Oh Shin J.
Published: October 2002

There has been one previously published antidromic method for studying medial calcaneal nerve (MCN) conduction. However, the origin of the compound nerve action potentials (CNAPs) with this technique is uncertain because of the antidromic nature of stimulation. We report a new orthodromic method for MCN conduction study using the near‐nerve needle technique. In 35 normal controls, maximum nerve conduction velocity (NCV) and negative‐peak NCV of MCN were 42.4 ± 3.9 m/s and 33.6 ± 3.0 m/s, respectively. The amplitude of the CNAP was 4.1 ± 2.2 μV. We also report four cases of medial calcaneal neuropathy, three of which were confirmed by this technique. We conclude that the present technique is capable of recording the sensory nerve action potentials of MCN in isolation and confirming the diagnosis of medial calcaneal neuropathy electrophysiologically. © 2002 Wiley Periodicals, Inc. Muscle Nerve 26: 654–658, 2002
Template elastic‐plastic computations in geomechanics
Authors: Jeremić Boris , Yang Zhaohui
Published: October 2002

In this paper we present a new approach to computations in elasto‐plastic geomechanics. The approach is based on the object oriented design philosophy and observations on similarity of most incremental elastic–plastic material models. This new approach to elastic–plastic computations in geomechanics allows for creation of template material models. The analysis of template material models will in turn allow for an easy implementation of other elastic–plastic material models based on the object oriented design principles. Furthermore we present some illustrative implementation details. Finally we present analysis results that emphasize features of template elastic–plastic computations in geomechanics. Copyright © 2002 John Wiley & Sons, Ltd.
Analytical and numerical investigation of uniqueness and localization in saturated porous media
Authors: Zhang H.W. , Schrefler B.A.
Published: October 2002

This paper presents first the applications of uniqueness and strain localization analysis of saturated porous media, where localization of deformation into well defined narrow zones in a saturated porous medium is studied in terms of discontinuous bifurcation theory. A generalized plasticity constitutive model and a Mohr–Coulomb model are used in both the theoretical and numerical analyses of shear band formations. The critical hardening moduli and shear band angle for localization are computed, and quantitative results are given for both constitutive models. Numerical results previously obtained and new ones are confirmed by this analytical and numerical investigation. Copyright © 2002 John Wiley & Sons, Ltd.
Analysis of steady‐state heat transfer through mid‐crustal vertical cracks with upward throughflow in hydrothermal systems
Authors: Zhao Chongbin , Hobbs B. E. , Mühlhaus H. B. , Ord A. , Lin Ge
Published: October 2002

We conduct a theoretical analysis of steady‐state heat transfer problems through mid‐crustal vertical cracks with upward throughflow in hydrothermal systems. In particular, we derive analytical solutions for both the far field and near field of the system. In order to investigate the contribution of the forced advection to the total temperature of the system, two concepts, namely the critical Peclet number and the critical permeability of the system, have been presented and discussed in this paper. The analytical solution for the far field of the system indicates that if the pore‐fluid pressure gradient in the crust is lithostatic, the critical permeability of the system can be used to determine whether or not the contribution of the forced advection to the total temperature of the system is negligible. Otherwise, the critical Peclet number should be used. For a crust of moderate thickness, the critical permeability is of the order of magnitude of 10−20m2, under which heat conduction is the overwhelming mechanism to transfer heat energy, even though the pore‐fluid pressure gradient in the crust is lithostatic. Furthermore, the lower bound analytical solution for the near field of the system demonstrates that the permeable vertical cracks in the middle crust can efficiently transfer heat energy from the lower crust to the upper crust of the Earth. Copyright © 2002 John Wiley & Sons, Ltd.
Hindbrain glucoprivic inhibition of the proestrus lutenizing hormone surge in the female rat is attenuated by exogenous lactate administration
Authors: Briski Karen P.
Published: October 2002

Central glucose availability is a critical monitored variable in the regulation of reproductive neuroendocrine function. While current studies implicate the periventricular caudal brainstem as a source of signaling of decreased availability of catabolic intermediates and/or glycolytic end products, the mechanisms by which local metabolic ‘sensors’ signal diminished glucose utilization are not clear. The present experiments investigated whether fourth ventricular infusion of the aerobic catabolic substrate, lactate, attenuates glucoprivic suppression of luteinizing hormone (LH). Cyclic female rats were injected at 13.00h on proestrus with the glucose antimetabolite, 2‐deoxy‐D‐glucose (2DG; 50 vs. 150ug), or vehicle into the rostral fourth ventricle. Additional proestrus animals were treated by continuous fourth ventricular infusion of 10.0 µM lactate/hr or vehicle, initiated prior to ip injection of 400mg 2DG/kg bw or saline. Serial blood samples were obtained hourly during proestrus afternoon for radioimmunoassay of plasma LH. The results demonstrate a reduction in the LH surge following icv 2DG administration, while showing that fourth ventricular infusion of lactate reversed inhibition of hormone release by systemic antimetabolite administration. These findings support the view that hindbrain signaling of glucose metabolic dysfunction initiates neural mechanisms that inhibit the proestrus LH surge, and that lactate utilization may be monitored as an indicator of local cellular energy stasis.
Brain‐specific carboxypeptidase B: selective down‐regulation in ependymal cell by irradiation and altered β‐amyloid processing
Authors: Kawabe Tetsuya , Sasaki Ryohei , Nishimura Hideki , Soejima Toshinori , Matsuyama Shogo , Sugimura Kazuro , Matusumoto Akira
Published: October 2002

Human brain carboxypeptidase B (HBCPB) is a brain protease expressed in a group of neuronal perikarya and ependymal cells, and cleaves β‐amyloid precursor protein (APP) in vitro, generating β‐amyloid (Aβ)‐bearing C‐terminal fragment of APP. To explore its physiological function, response to external stress, such as ionizing radiation, and expression in mouse brain were studied. Mouse head was irradiated at 10 Gy, then brains were excised before or after 1h until 9 d of irradiation. They were analyzed using TUNEL assay and anti C14‐module antibody which detects epitopes unique to HBCPB, and western analysis. The mouse HBCPB‐homologue cleaved mouse brain APP in vitro. Morphological study indicated its identical distribution to HBCPB. During 2 h after irradiation, the HBCPB‐homologue expression in edendymal cells, but not in neurons, decreases transiently, and recovers within 4 h. Concomitantly, processing of APP is altered, increasing generation of the C‐terminal 12 kDa fragment. Since APP participates in cellular response to tolerance in CNS, this finding suggests that radiation‐induced APP processing and differential response in its expression between ependymal cells and neurons are associated with important physiological function in CNS.
Cyclosporine‐A delays the end‐plate degeneration in denerved rat muscles
Authors: Rodella Luigi , Bonaspetti Giovanni , Rezzani Rita , Borsani Elisa , Fenu Riccardo , Pazzaglia Ugo , Bianchi Rossella
Published: October 2002

When an adult skeletal muscle is denervated, its end‐plates degenerate and their acethylcholinesterase (AChE) activity gradually decreases. However, if the proximal segment of the nerve is sutured to the distal segment, or if the nerve is implanted in a previous denerved muscle the axons regenerate and reconstitute new end‐plates over a variable period. This period depends on the time passed between the nerve cutting and the reimplantation suggesting that the degenerative processes are closely correlated to regeneration. It has been shown that cyclosporine‐A (CsA) is useful in nerve regeneration but their role in nerve degeneration is not well understand. We evaluated, using AChE histochemistry, the effects of CsA, on the degeneration of the end‐plates in an experimental model of gastrocnemius muscle denervation in the rat. CsA at a dose of 15 mg/kg/day did not cause any quantitative or qualitative alterations in the end‐plates on normal rat muscles. Moreover, our findings showed that CsA reduced the end‐plate degeneration and loss in the denerved rat muscles.
Tissue xanthine oxidase activity and nitric oxide levels after spinal cord ischemia/reperfusion injury in rabbits: comparison of caffeic acid phenethyl ester (CAPE) and methylprednisolone
Authors: Şahin Şemsettin , Söğüt Sadık , Özyurt Hüseyin , Uz Efkan , İlhan Atilla , Akyol Ömer
Published: October 2002

Caffeic acid phenethyl ester exhibits antioxidant properties. This experimental study was designed to determine the effect of CAPE on nitric NO level and XO activity after reperfusion injury of spinal cord. New Zealand white rabbits were undergone aortic occlusion. CAPE, methylprednisolone or saline were injected intraperitoneally before surgical intervention. Animals were subjected to 21 min of crossclamp time. At the end of occlusion time, the clamps were removed and restoration of the blood flow was verified visually. Animals in sham group underwent a surgical procedure similar to the other groups but the aorta was not occluded. Spinal cord specimens were obtained to determine the tissue levels of NO and XO activity.

Both XO activity and NO level in ischemia group were significantly higher than those of sham group (p = 0.0005 and 0.0003, respectively). MP and CAPE had no effect on XO activity after reperfusion. These two agents decreased NO levels nearly to that of sham group after reperfusion. There were no differences between MP and CAPE on reducing NO level. These results suggest that rabbits with ischemia‐reperfusion injury in spinal cord have increased cord concentrations of nitrite and nitrate that are indicative of endogenous overproduction of NO. CAPE may be regarded as an agent that protects spinal cord from ischemia‐reperfusion injury.
Mechanisms of bicuculline‐induced hypersensitivity of medullary dorsal horn neurons in rats
Authors: Nam Soon H. , Seo Jeong P. , J. Kim Young , Kim Hyun J. , Ju Jin S. , Ahn Dong K.
Published: October 2002

The purpose of the present study was to examine the responses of medullary dorsal horn neurons to microiontophoretic application of the γ‐aminobutyric acid (GABA)A receptor antagonist, bicuculline. The mechanisms of bicuculline‐induced hypersensitivity were also investigated. Extracellular recordings were made with the central barrel of a seven‐barrel micropipette. Microiontophoretic application of bicuculline greatly increased N‐methyl‐D‐aspartic acid (NMDA)‐evoked responses of medullary dorsal horn neurons. Bicuculline also increased the responses to both noxious pinching and brushing of cutaneous receptor fields. Both NMDA and non‐NMDA receptor antagonists blocked the facilitated responses to iontophoretic application of bicuculline. However, the mu and delta receptor agonists did not block the hypersensitivity produced by iontophoretic application of bicuculline. These results suggest that GABA modulates the synaptic transmission of both noxious and non‐noxious information in the trigeminal spinal sensory nuclei. Bicuculline‐induced hypersensitivity seems to be mediated by excitatory amino acid receptors and provides a mechanism for neuropathic pain.
Structures of X 34‐nylons in chain‐folded lamellae and gel‐spun fibers
Authors: Ehrenstein Moritz , Sikorski Pawel , Atkins Edward , Smith Paul
Published: October 2002

Structural studies and morphological features of a new family of linear, aliphatic even–even, X 34‐nylons, with X = 2, 4, 6, 8, 10, and 12, are investigated with X‐ray diffraction and electron microscopy. Solution‐grown crystals were obtained by isothermal crystallization from N,N‐dimethylformamide solutions. The thickness of lamellar‐like crystals was orders of magnitude less than the chain lengths of the polymer samples used, implying that the chains fold to form chain‐folded lamellae. The results bear a close resemblance, with the noticeable exception of 2 34‐nylon, to those reported for nylon 6 6 and other even–even nylon chain‐folded lamellar crystals. The basic structure of the straight‐stem lamellar core is similar to that of the classic nylon 6 6 triclinic α structure, and the chains tilt ≈42° relative to the lamellar normal. In the case of 2 34‐nylon, the structure resembles the 2 Y nylon series, and the chain tilt angle reduces to 36.6°. These combined results suggest that, even with a relatively low frequency of amide units along the backbone of these molecules, hydrogen bonding is still the dominant element in controlling the behavior, structure, and properties of these polymers. In addition, gels were prepared in concentrated sulfuric acid, and gel‐spun fibers were studied using X‐ray diffraction. The data are interpreted in terms of a modified nylon triclinic α structure that bears a resemblance to the structure of even–even nylons at elevated temperatures. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 2685–2692, 2002
Components of microstrain in polyethylene
Authors: Brown Norman , Rabinowitz Stephen
Published: October 2002

Tensile microstrain was measured in high‐density polyethylene with a precision of 2 × 10−7 for strains up to 10−4 in the temperature range of 17–28 °C over a range of strain rates. The total strain was partitioned into three of the following components: (1) elastic, (2) amorphous, and (3) dislocation. Also, their respective dependence on stress was determined. Measurements of the area of the hysteresis loops gave the energy loss per cycle from which the frictional stress on the amorphous flow and the dislocations was determined. Although the amorphous strain originated at zero stress and was dependent on the temperature and strain rate, the dislocation motion was activated above acritical stress and independent of temperature and strain rate within the scope of these experiments. The viscosity of the amorphous flow was determined. The effect of 5 Mrd γ irradiation on the micro‐deformation behavior was not appreciable. About 80 Mrd reduced the amorphous flow by about 30% and increased the stress to activate the motions of the dislocations. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 2693–2701, 2002
Effect of selected structural parameters of styrene–butadiene block copolymers on their compatibilization efficiency in polystyrene/polybutadiene blends
Authors: Horák Z. , Hlavatá D. , Hromádková J. , Kotek J. , Hašová V. , Mikešová J. , Pleska A.
Published: October 2002

The effects of the block length and block number of linear styrene–butadiene (S–B) block copolymers on their compatibilization efficiency in blending polystyrene with polybutadiene were studied. For this purpose, two sets of model S–B copolymers and both homopolymers were prepared by anionic polymerization. Diblocks, triblocks, or pentablocks of S–B copolymers were blended with these homopolymers, and the structures and some end‐use properties of the blends were determined. The supramolecular structure (determined by small‐angle X‐ray scattering), morphology (determined by transmission and scanning electron microscopy), and stress‐transfer characteristics (impact and tensile strengths) of the blends were chosen as criteria for the compatibilization efficiency of the copolymers used. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 2612–2623, 2002
Direct formation of form I poly(1‐butene) single crystals from melt crystallization in ultrathin films
Authors: Zhang Bin , Yang Decai , Yan Shouke
Published: October 2002

The morphologies and crystalline structures of melt‐crystallized ultrathin isotactic poly(1‐butene) films have been studied with transmission electron microscopy and electron diffraction. It is demonstrated that a bypass of form II crystallization can be achieved with an increase in its crystallization temperature. Electron microscopy observations show that melt‐grown isotactic poly(1‐butene) single crystals have a well‐shaped hexagonal form, whereas form I crystals converted from form II display the morphologies of their tetragonal precursors. Electron diffraction results indicate that, instead of the twinned hexagonal pattern of the converted form I crystal, the directly formed form I single crystals exhibit an untwinned hexagonal pattern. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 2641–2645, 2002
Crystalline structure and morphology of biaxially oriented polyamide‐11 films
Authors: Rhee Sangkeun , White James L.
Published: October 2002

The effect of the uniaxial and biaxial stretching and subsequent solution annealing of extrusion‐cast polyamide‐11 films on the crystalline structure and morphology was investigated with differential scanning calorimetry, wide‐angle X‐ray diffraction (WAXD), Fourier transform infrared spectroscopy, and small‐angle X‐ray scattering (SAXS). The extrusion‐cast polyamide‐11 films exhibited elevations in the glass‐transition and cold‐crystallization temperatures with a constant crystallinity and a constant melting point during aging under room conditions (20–26 °C and 20–31% relative humidity). WAXD and SAXS suggested that chain‐folded lamellae of coexisting α‐ and β‐crystals existed in all the stretched polyamide‐11 films. WAXD pole figures indicated that hydrogen bonds in the hydrogen‐bonded sheets of these two crystalline forms apparently formed between antiparallel chain molecules. The unit cell parameters [a = 9.52 Å, b = 5.35 Å, c = 14.90 Å (chain axis), α = 48.5°, β = 90°, and γ = 74.7° for a triclinic α form and a = 9.52 Å, b = 14.90 Å (chain axis), c = 4.00 Å, α = 90°, β = 67.5°, and γ = 90° for a monoclinic β form] for polyamide‐11 crystals were proposed according to the results of this study and the results of previous investigators. The unit cell parameters of the stretched extrusion‐cast polyamide‐11 films varied, depending on the stretching conditions (the stretch temperature and stretch ratio). As the stretch temperature and stretch ratio were increased, the crystal became more similar to the form described previously and was accompanied by an increase in the long spacing of crystalline lamellae. Annealing the stretched films in a boiling 20% formic acid solution made slightly more perfected crystals. The hydrogen‐bonding α(010) + β(002) planes, which are nearly parallel to both amide group planes and zigzag methylene sequence planes of the biaxially stretched films were found to be parallel to the film surface. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 2624–2640, 2002
Nonatomic solvent‐driven voronoi tessellation of proteins: An open tool to analyze protein folds
Authors: Angelov Borislav , Sadoc Jean‐François , Jullien Rémi , Soyer Alain , Mornon Jean‐Paul , Chomilier Jacques
Published: October 2002

A three‐dimensional Voronoi tessellation of folded proteins is used to analyze geometrical and topological properties of a set of proteins. To each amino acid is associated a central point surrounded by a Voronoi cell. Voronoi cells describe the packing of the amino acids. Special attention is given to reproduction of the protein surface. Once the Voronoi cells are built, a lot of tools from geometrical analysis can be applied to investigate the protein structure; volume of cells, number of faces per cell, and number of sides per face are the usual signatures of the protein structure. A distinct difference between faces related to primary, secondary, and tertiary structures has been observed. Faces threaded by the main‐chain have on average more than six edges, whereas those related to helical packing of the amino acid chain have less than five edges. The faces on the protein surface have on average five edges within 1% error. The average number of faces on the protein surface for a given type of amino acid brings a new point of view in the characterization of the exposition to the solvent and the classification of amino acid as hydrophilic or hydrophobic. It may be a convenient tool for model validation. Proteins 2002;49:446–456. © 2002 Wiley‐Liss, Inc.
Data mining the protein data bank: Residue interactions
Authors: Oldfield T.J.
Published: October 2002

The protein databank contains a vast wealth of structural and functional information. The analysis of this macromolecular information has been the subject of considerable work in order to advance knowledge beyond the collection of molecular coordinates. This article presents a method that determines local structural information within proteins using mathematical data mining techniques. The mine program described returns many known configurations of residues such as the catalytic triad, metal binding sites and the N‐linked glycosylation site; as well as many other multiple residue interactions not previously categorized. Because mathematical constructs are used as targets, this method can identify new information not previously known, and also provide unbiased results of typical structure and their expected deviations. Because the results are defined mathematically, they cannot indicate the biological implications of the results. Therefore two support programs are described that provide insight into the biological context for the mine results. The first allows a weighted RMSD search between a template set of coordinates and a list of PDB files, and the second allows the labeling of a protein with the template results from mining to aid in the classification of this protein. Proteins 2002;49:510–528. © 2002 Wiley‐Liss, Inc.
Solution structure of the DNA‐binding domain of interleukin enhancer binding factor 1 (FOXK1a)
Authors: Liu Pei‐Phen , Chen Yen‐Chin , Li Ching , Hsieh Yu‐Huei , Chen Shu‐Wan , Chen Shu‐Huei , Jeng Wen‐Yih , Chuang Woei‐Jer
Published: October 2002

Interleukin enhancer binding factor (ILF) binds to the interleukin‐2 (IL‐2) promoter and regulates IL‐2 gene expression. In this study, the 3D structure of the DNA‐binding domain of ILF was determined by multidimensional NMR spectroscopy. NMR structure analysis revealed that the DNA‐binding domain of ILF is a new member of the winged helix/forkhead family, and that its wing 2 contains an extra α‐helix. This is the first study to report the presence of a C‐terminal α‐helix in place of a typical wing 2 in a member of this family. This structural difference may be responsible for the different DNA‐binding specificity of ILF compared to other winged helix/forkhead proteins. Our deletion studies of the fragments of ILF also suggest that the C‐terminal region plays a regulatory role in DNA binding. Proteins 2002;49:543–553. © 2002 Wiley‐Liss, Inc.
Origins of protein denatured state compactness and hydrophobic clustering in aqueous urea: Inferences from nonpolar potentials of mean force
Authors: Shimizu Seishi , Chan Hue Sun
Published: October 2002

Free energies of pairwise hydrophobic association are simulated in aqueous solutions of urea at concentrations ranging from 0–8 M. Consistent with the expectation that hydrophobic interactions are weakened by urea, the association of relatively large nonpolar solutes is destabilized by urea. However, the association of two small methane‐sized nonpolar solutes in water has the opposite tendency of being slightly strengthened by the addition of urea. Such size effects and the dependence of urea‐induced stability changes on the configuration of nonpolar solutes are not predicted by solvent accessible surface area approaches based on energetic parameters derived from bulk‐phase solubilities of model compounds. Thus, to understand hydrophobic interactions in proteins, it is not sufficient to rely solely on transfer experiment data that effectively characterize a single nonpolar solute in an aqueous environment but not the solvent‐mediated interactions among two or more nonpolar solutes. We find that the m‐values for the rate of change of two‐methane association free energy with respect to urea concentration is a dramatically nonmonotonic function of the spatial separation between the two methanes, with a distance‐dependent profile similar to the corresponding two‐methane heat capacity of association in pure water. Our results rationalize the persistence of residual hydrophobic contacts in some proteins at high urea concentrations and explain why the heat capacity signature (ΔCP) of a compact denatured state can be similar to ΔCP values calculated by assuming an open random‐coil‐like unfolded state. Proteins 2002;49:560–566. © 2002 Wiley‐Liss, Inc.
An intervention study to enhance girls' interest, self‐concept, and achievement in physics classes
Authors: Häussler Peter , Hoffmann Lore
Published: October 2002

Many interest studies have shown the decline of students' interest in physics during secondary education, particularly among girls. Research into physics‐related interests of students suggests applying different measures to reduce or reverse that trend such as: (a) suggesting curricular changes that do justice to the specific interests and experiences of girls, (b) improving the ability of teachers to support girls in the development of a positive physics related self‐concept, and (c) changing to an organizational setting that gives girls a better chance to improve their self‐concept about physics. The purpose of this study was to examine whether these hypothetically effective measures lead to an improvement of the situation for girls when implemented in the physics classroom. The intervention took a whole school year of some 60 one‐hour lessons and comprised 12 experimental and 7 control classes of seventh graders (age about 13). Their immediate and long‐term achievements, as well as their change of interest in physics, their subjectively experienced competence, and their physics‐related self‐concept were assessed by written tests at various stages of the intervention. The intervention proved successful and significantly improved most of these indicators for girls (and boys) in the experimental group. © 2002 Wiley Periodicals, Inc. J Res Sci Teach 39: 870–888, 2002
Analysis of students' assessments in middle school curriculum materials: Aiming precisely at benchmarks and standards
Authors: Stern, Luli , Ahlgren Andrew
Published: October 2002

Assessment influences every level of the education system and is one of the most crucial catalysts for reform in science curriculum and instruction. Teachers, administrators, and others who choose, assemble, or develop assessments face the difficulty of judging whether tasks are truly aligned with national or state standards and whether they are effective in revealing what students actually know. Project 2061 of the American Association for the Advancement of Science has developed and field‐tested a procedure for analyzing curriculum materials, including their assessments, in terms of how well they are likely to contribute to the attainment of benchmarks and standards. With respect to assessment in curriculum materials, this procedure evaluates whether this assessment has the potential to reveal whether students have attained specific ideas in benchmarks and standards and whether information gained from students' responses can be used to inform subsequent instruction. Using this procedure, Project 2061 had produced a database of analytical reports on nine widely used science middle school curriculum materials. The analysis of assessments included in these materials shows that whereas currently available materials devote significant sections in their instruction to ideas included in national standards documents, students are typically not assessed on these ideas. The analysis results described in the report point to strengths and limitations of these widely used assessments and identify a range of good and poor assessment tasks that can shed light on important characteristics of good assessment. © 2002 Wiley Periodicals, Inc. J Res Sci Teach 39: 889–910, 2002
Simultaneous determination of potassium and rubidium content in yeast
Authors: Mulet Jose M. , Serrano Ramón
Published: October 2002

Rubidium is widely used as a potassium analogue in transport studies in yeast and other organisms. As rubidium (potassium) uptake is modulated by the internal potassium concentration, it is often necessary to determine both Rb+ and K+ concentrations in the same cell extract. Current methods based on atomic absorption/emission spectroscopy require separate analysis for each cation. Alternatively, unsafe radioactive isotopes can be used. Here we report a convenient, non‐radioactive, HPLC/conductivity‐based method that allows a complete analysis of both cations with a single injection from a cell extract. The increase in Rb+ uptake during K+ starvation in yeast is easily demonstrated with this method. Copyright © 2002 John Wiley & Sons, Ltd.
Proteins interacting with Lin1p, a putative link between chromosome segregation, mRNA splicing and DNA replication in Saccharomyces cerevisiae
Authors: Bialkowska Agnieszka , Kurlandzka Anna
Published: October 2002

Proteins involved in chromosome segregation during mitosis are likely to participate in other cell cycle‐coordinated processes. Using a two‐hybrid screen we identified a novel nuclear protein, Lin1, interacting with Irr1p/Scc3p, a component of the cohesin complex. The second round of two‐hybrid assay with Lin1p as the bait resulted in the identification of six proteins: Prp8, Slx5, Siz2, Wss1, Rfc1 and YIL149w. These proteins have previously been shown to participate in mRNA splicing, DNA replication, chromosome condensation, chromatid separation and alternative cohesion. We propose that Lin1p may constitute a link among these processes. Copyright © 2002 John Wiley & Sons, Ltd.
Specificity of substrate recognition by type II dehydroquinases as revealed by binding of polyanions1
Authors: Evans Lewis D.B , Roszak Aleksander W , Noble Lorna J , Robinson David A , Chalk Peter A , Matthews Jennifer L , Coggins John R , Price Nicholas C , Lapthorn Adrian J
Published: October 2002

The interactions between the polyanionic ligands phosphate and sulphate and the type II dehydroquinases from Streptomyces coelicolor and Mycobacterium tuberculosis have been characterised using a combination of structural and kinetic methods. From both approaches, it is clear that interactions are more complex in the case of the latter enzyme. The data provide new insights into the differences between the two enzymes in terms of substrate recognition and catalytic efficiency and may also explain the relative potencies of rationally designed inhibitors. An improved route to the synthesis of the substrate 3‐dehydroquinic acid (dehydroquinate) is described.
4α‐Phorbol negates the inhibitory effects of phorbol‐12‐myristate‐13‐acetate on human cilia and alters the phosphorylation of PKC
Authors: Mwimbi Xowi K.M.S , Muimo Richmond , Treharne Kate J , Sijumbila Gibson , Green Michael , Mehta Anil
Published: October 2002

In medium 199, ciliary beat frequency (CBF) in human nasal epithelium declines to 60% of baseline by 2 h and 1 nM phorbol‐12‐myristate‐13‐acetate (PMA) doubles the rate of decline by activating protein kinase C (PKC). We find that a reported negative control for PMA, 4α‐phorbol (1 pM–1 nM)±1 nM PMA, not only maintains CBF at baseline, but arrests a pre‐existing PMA‐induced decline in CBF and alters the profile of multiple phosphorylated PKC species. Thus, 4α‐phorbol not only potently prevents PMA from inhibiting CBF but also has potent effects on the phosphorylation of PKC.
The short N‐terminus is required for functional expression of the virus‐encoded miniature K+ channel Kcv
Authors: Moroni Anna , Viscomi Carlo , Sangiorgio Vanessa , Pagliuca Cinzia , Meckel Tobias , Horvath Ferenc , Gazzarrini Sabrina , Valbuzzi Paola , Van Etten James L , DiFrancesco Dario , Thiel Gerhard
Published: October 2002

Kcv (K+ Chlorella virus) is a miniature virus‐encoded K+ channel. Its predicted membrane–pore–membrane structure lacks a cytoplasmic C‐terminus and it has a short 12 amino acid (aa) cytoplasmic N‐terminus. Kcv forms a functional channel when expressed in human HEK 293 cells. Deletion of the 14 N‐terminal aa results in no apparent differences in the subcellular location and expression level of the Kcv protein. However, the truncated protein does not induce a measurable current in transfected HEK 293 cells or Xenopus oocytes. We conclude that the N‐terminus controls functional properties of the Kcv channel, but does not influence protein expression.
Reg protein is overexpressed in gastric cancer cells, where it activates a signal transduction pathway that converges on ERK1/2 to stimulate growth
Authors: Kadowaki Yasunori , Ishihara Shunji , Miyaoka Youichi , Rumi Mohammed Azharul Karim , Sato Hiroshi , Kazumori Hideaki , Adachi Kyoichi , Takasawa Shin , Okamoto Hiroshi , Chiba Tsutomu , Kinoshita Yoshikazu
Published: October 2002

Reg is a growth factor with mitogenic effects on pancreatic β cells and gastric stem cells. To date, there has been no information available on Reg‐mediated intracellular signal transduction pathways. The role of Reg in the gastric carcinogenesis is also unknown. In the current study, the Reg signaling pathway in gastric cancer cell was examined. Reg treatment of MKN45 gastric cancer cells resulted in tyrosyl‐phoshorylation of several cellular proteins and subsequent activation of classical MAPK, ERK1/2. Reg also stimulated thymidine incorporation in MKN45 and AGS gastric cancer cells in a dose‐dependent manner. Finally, Reg was shown to be highly expressed in a large number of gastric cancers in vivo. Taken together, these data suggest that gastric cancer cells have gained the ability to overexpress Reg protein, which confer upon themselves added proliferative capacities, resulting in a considerable growth advantage.
Doppel and PrPC do not share the same membrane microenvironment
Authors: Shaked Yuval , Hijazi Nuha , Gabizon Ruth
Published: October 2002

Doppel is a paralog of the normal prion protein, PrPC. It has been suggested that Doppel can compensate for the absence of PrPC in PrP0/0 mice. In this work, we tested whether Doppel and PrPC share the same cell location, thereby sharing the same neighboring cell components, probably required to share the same cell function. Our results show that, at detergent conditions in which membrane rafts were intact, neither PrPC and Doppel co‐immunoprecipitate with the appropriate antibodies, nor was Doppel retained by a Cu2+IMAC resin, as PrPC does. This indicates that, although Doppel is a raft‐associated protein as is PrPC, both proteins are not present in the same membrane microenvironment, and they probably do not perform the same function.
V‐1, a catecholamine biosynthesis regulatory protein, positively controls catecholamine secretion in PC12D cells
Authors: Yamakuni Tohru , Yamamoto Toshifumi , Ishida Yukisato , Yamamoto Hideko , Song Si-Young , Adachi Eijiro , Hiwatashi Yusuke , Ohizumi Yasushi
Published: October 2002

Stably transfected PC12D cell lines overexpressing a catecholamine biosynthesis regulatory protein, V‐1, were used to examine the functional role of V‐1 in catecholamine secretion. High K+‐induced dopamine secretion in V‐1 overexpressing clones was shown to be markedly potentiated compared with control clones carried with a vector alone. As assayed intracellular calcium concentration ([Ca2+]i) using fura‐PE3, V‐1 overexpression was observed to enhance high K+‐elicited [Ca2+]i elevation. Electron microscopic analysis revealed an increase in dense‐cored vesicle formation by V‐1 overexpression. These results suggest that the enhancement of high K+‐induced dopamine secretion by V‐1 overexpression results from the potentiation of high K+‐induced [Ca2+]i elevation and the increase in the number of dense‐cored vesicles.
New advances on structural and biological functions of ceramide in apoptotic/necrotic cell death and cancer
Authors: Mimeault Murielle
Published: October 2002

Recent data on the cellular ceramide functions and its involvement in the apoptotic/necrotic cell death as well as its anticarcinogenic properties are presented. The emphasis is on the connections between the ceramide and caspase signaling pathways during the apoptotic cell death process. Notably, the experimental strategies and pharmacological tools used for establishment of the role of ceramide in triggering cell death are described. Moreover, the importance of a compartmentation of endogenous ceramide within the plasma membrane microdomains, lysosomes and mitochondria is discussed. Information on the deregulated functions of ceramide and caspase signaling pathways in several metastatic cancer types is also presented.
Binding affinities and protein ligand complex geometries of nucleotides at the F1 part of the mitochondrial ATP synthase obtained by ligand docking calculations
Authors: Steinbrecher Thomas , Hucke Oliver , Steigmiller Stefan , Börsch Michael , Labahn Andreas
Published: October 2002

F0F1 ATP synthases utilize a transmembrane electrochemical potential difference to synthesize ATP from ADP and phosphate. In this work, the binding modes of ADP, ATP and ATP analogues to the catalytic sites of the F1 part of the mitochondrial ATP synthase were investigated with ligand docking calculations. Binding geometries of ATP and ADP at the three catalytic sites agree with X‐ray crystal data; their binding free energies suggest an assignment to the ‘tight’, ‘open’ and ‘loose’ states. The rates of multi‐site hydrolysis for two fluorescent ATP derivatives were measured using a fluorescence assay. Reduced hydrolysis rates compared to ATP can be explained by the ligand docking calculations.
Tumour necrosis factor‐α interacts with biglycan and decorin
Authors: Tufvesson Ellen , Westergren-Thorsson Gunilla
Published: October 2002

Several interactions of cytokines with extracellular matrix molecules are mediated by proteoglycans, such as biglycan and decorin. Using surface plasmon resonance, we show for the first time that tumour necrosis factor‐α (TNF‐α) binds to both biglycan and decorin with K
ds of 0.81 μM and 1.23 μM respectively, a binding that was confirmed by Scatchard plots using a solid phase assay. Binding occurs preferentially via the core protein, shown by lower K
ds, 0.26 μM and 0.81 μM for biglycan and decorin respectively. There was also binding to dermatan sulphate, with a K
d of 10.53 μM. The function of this interaction between TNF‐α and biglycan and decorin is not known, but we suggest that the differential localisation of the proteoglycans enables the cytokines to be immobilised in different environments.
Gut‐enriched Krüppel‐like factor regulates colonic cell growth through APC/β‐catenin pathway
Authors: Stone Christian D , Chen Zhi Y , Tseng Chi-Chuan
Published: October 2002

Studies on colorectal carcinogenesis have suggested a critical role of the adenomatous polyposis coli (APC) gene in the development of colorectal cancer. Gut‐enriched Krüppel‐like factor (GKLF) is a zinc‐finger transcription protein with high expression in the colonic epithelium. Our previous studies have shown that GKLF transcript was significantly decreased in colon cancer tissue and suggested that it might play a role in the tumorigenesis of the colon. The signaling pathway of GKLF‐regulated cell growth is currently unknown. We sought to determine if the functions of GKLF are mediated through the APC/β‐catenin pathway. In a colon cancer cell line (HT29‐APC), containing a zinc‐inducible APC gene, GKLF mRNA levels were significantly increased when wild‐type APC protein was induced. No effect on GKLF mRNA concentration was observed in a control cell line (HT29‐β‐gal), containing an analogous inducible lacZ gene. GKLF promoter activity was induced by co‐transfection with wild‐type APC DNA, suggesting that APC might be involved in transcriptional activation of the GKLF gene. In HT‐29 cells, overexpression of GKLF resulted in decreases in β‐catenin protein and mRNA levels and down‐regulation of GKLF expression led to increase in β‐catenin concentration. Overexpression of GKLF in HT‐29 cells inhibited DNA synthesis and this effect was attenuated by co‐transfection with wild‐type β‐catenin, suggesting an essential role of β‐catenin in GKLF signaling. Furthermore, co‐transfection of GKLF in colon cancer SW 480 cells abrogated the transcriptional activity of a β‐catenin‐T‐cell factor (Tcf) reporter construct in a dose‐dependent manner. These findings indicate that the growth‐suppressive effect of GKLF may be mediated through the APC/β‐catenin pathway. We speculate that when APC is mutated, GKLF gene expression is down‐regulated, resulting in increases in β‐catenin level and transactivation of growth‐promoted genes.
Thermally stable and hydrogen peroxide tolerant manganese peroxidase (MnP) from Lenzites betulinus
Authors: Hoshino Fumihiko , Kajino Tsutomu , Sugiyama Hidehiko , Asami Osamu , Takahashi Haruo
Published: October 2002

A thermally stable and hydrogen peroxide tolerant manganese peroxidase (MnP) was purified from the culture medium of Lenzites betulinus by ion exchange chromatography, gel filtration and isoelectric focusing chromatography. The MnP purified from L. betulinus (L‐MnP) has a molecular mass of 40 kDa and its isoelectric point was determined to be 6.2. The first 19 amino acids at the N‐terminal end of the L‐MnP sequence were found to exhibit 74% identity with those of a Phlebia radiata MnP. L‐MnP was proved to have the highest hydrogen peroxide tolerance among MnPs reported so far. It retained more than 60% of the initial activity after thermal treatment at 60°C for 60 min, and also retained more than 60% of the initial activity after exposure to 10 mM hydrogen peroxide for 5 min at 37°C.