bluuebunny/crossref_metadata_2025 huggingface dataset:
The monoamine reuptake inhibitor BTS 74 398 fails to evoke established dyskinesia but does not synergise with levodopa in MPTP‐treated primates
Authors: Hansard Matthew J. , Smith Lance A. , Jackson Michael J. , Cheetham Sharon C. , Jenner Peter
Published: January 2004

Long‐term treatment of Parkinson's disease (PD) with levodopa (L‐dopa) induces dyskinesia that, once established, is provoked by each dose of L‐dopa or a dopamine (DA) agonist. In contrast, monoamine reuptake inhibitors may reverse motor deficits in 1‐methyl‐4‐phenyl‐1,2,3,6‐tetrahydropyridine (MPTP)‐treated primates without provoking established involuntary movements. We now examine whether the potent monoamine reuptake blocker BTS 74 398 induces established dyskinesia in MPTP‐treated common marmosets primed previously with L‐dopa and whether co‐administration of BTS 74 398 with L‐dopa potentiates motor behaviour and dyskinesia induced by acute L‐dopa treatment. Administration of BTS 74 398 (2.5, 5.0, or 10.0 mg/kg, p.o.) in MPTP‐treated common marmosets increased locomotor activity and reduced motor disability in a dose‐related manner but did not provoke involuntary movements. BTS 74 398 (2.5, 5.0, or 10.0 mg/kg p.o.) co‐administered with a threshold dose of L‐dopa (2.5 mg/kg p.o.) did not evoke a motor response or induce dyskinesia. Similarly, concomitant administration of BTS 74 398 (5.0 mg/kg p.o.) with a submaximal L‐dopa dose (12.5 mg/kg p.o.) did not potentiate the motor response produced by L‐dopa alone and there was no alteration in the dyskinesia provoked by L‐dopa challenge. BTS 74 398 reverses motor abnormalities in MPTP‐treated marmosets without evoking established dyskinesia but no additive improvement occurs when administered in combination with L‐dopa. The lack of synergy with L‐dopa may suggest different sites of drug action. © 2003 Movement Disorder Society
Cortical motor activation in akinetic schizophrenic patients: A pilot functional MRI study
Authors: Payoux Pierre , Boulanouar Kader , Sarramon Christine , Fabre Nelly , Descombes Sylvie , Galitsky Monique , Thalamas Claire , Brefel‐Courbon Christine , Sabatini Umberto , Manelfe Claude , Chollet François , Schmitt Laurent , Rascol Olivier
Published: January 2004

Akinesia is associated with supplementary motor area (SMA) dysfunction in Parkinson's disease. We looked for a similar association in patients with schizophrenia. Using functional magnetic resonance imaging (fMRI), we compared motor activation in 6 akinetic neuroleptic‐treated schizophrenic patients and 6 normal subjects. Schizophrenic patients had a defective activation in the SMA, left primary sensorimotor cortex, bilateral lateral premotor and inferior parietal cortices, whereas the right primary sensorimotor cortex and a mesial frontal area were hyperactive. SMA was hypoactive in akinetic schizophrenic patients, emphasizing the role of this area in motor slowness. Other abnormal signals likely reflect schizophrenia‐related abnormal intracortical connections. © 2003 Movement Disorder Society
Quetiapine improves psychotic symptoms and cognition in Parkinson's disease
Authors: Juncos Jorge L. , Roberts Vicki J. , Evatt Marian L. , Jewart Rita D. , Wood Colleen D. , Potter Larry S. , Jou Hann‐Chang , Yeung Paul P.
Published: January 2004

Twenty‐nine elderly patients who failed treatment with clozapine, risperidone, or olanzapine entered this 24‐week, single‐center, open‐label trial to assess the efficacy of quetiapine (12.5–400 mg/day) for psychosis in patients with Parkinson's disease (PD). Psychiatric, motor, and cognitive assessments were administered at baseline and at periodic intervals for 24 weeks. These included the Brief Psychiatric Rating Scale (BPRS), Neuropsychiatric Inventory (NPI), Unified Parkinson's Disease Rating Scale (UPDRS) and tests of intellectual functioning, attention, and memory. Repeated measures statistical analysis was used to assess change from baseline. The results revealed significant improvements in the 24‐week BPRS total score and NPI psychosis subscale scores, with no decline in UPDRS total or motor subscale scores. There was also significant improvement in recall scores on cognitive measures. These results indicate that quetiapine may treat psychotic symptoms and improve cognition without worsening motor function in patients with PD, suggesting that quetiapine is an effective and well‐tolerated antipsychotic in this population. © 2003 Movement Disorder Society
DNA sequence analysis of monoamine oxidase B gene coding and promoter regions in Parkinson's disease cases and unrelated controls
Authors: Costa‐Mallen Paola , Afsharinejad Zahra , Kelada Samir N. , Costa Lucio G. , Franklin Gary M. , Swanson Phillip D. , Longstreth W.T. , Viernes Hannah‐Malia A. , Farin Federico M. , Smith‐Weller Terri , Checkoway Harvey
Published: January 2004

The allele G of the intron 13 G/A polymorphism of the monoamine oxidase B gene (MAO‐B) has been associated with Parkinson's disease (PD) in several studies. Apart from a potential direct effect on splicing processes, the association of this intronic polymorphism with PD is due possibly to linkage disequilibrium with other mutations in the coding or promoter regions of the gene. We addressed this latter hypothesis by determining the DNA sequence of the entire MAO‐B coding region comprising 15 exons and partial intronic sequences flanking each exon, in 33 cases with idiopathic PD and 38 unrelated controls. The promoter region of MAO‐B gene up to base −1,369 from ATG (start point of mRNA translation) was also sequenced to identify variants with potential functional effects on gene transcription. In the promoter region, a new polymorphism consisting of a C to T single base change was detected in position −1,114 from ATG, with an allelic frequency of 3.5%, but it was not associated with PD risk. No commonly occurring (>10%) polymorphisms were found in the exons or the intronic sequences flanking the exons, although several rare variants were detected in the coding and promoter regions. © 2003 Movement Disorder Society
Comparison of dementia with Lewy bodies to Alzheimer's disease and Parkinson's disease with dementia
Authors: Noe Enrique , Marder Karen , Bell Karen L. , Jacobs Diane M. , Manly Jennifer J. , Stern Yaakov
Published: January 2004

We compared the clinical and neuropsychological pattern of dementia with Lewy bodies (DLB) to Alzheimer's disease (AD) and Parkinson's disease with dementia (PD‐d). Sixteen patients clinically diagnosed with DLB were compared with two groups of patients with PD‐d (n = 15) and AD (n = 16) matched for level of dementia. Isolated cognitive impairment was the most common form of presentation in AD (93.8%) and DLB (31.3%) groups, while parkinsonism was in 100% of PD‐d subjects. Psychoses associated with cognitive impairment at the beginning of the disease were more frequent in DLB patients (31.3%) than in AD (6.3%) and PD‐d (0%) groups. There were no significant differences in Unified Parkinson Disease Rating Scale motor‐subscale scores between DLB and PD‐d patients. DLB and PD‐d patients performed significantly worse on attentional functions and better on memory tests than AD. DLB patients also showed lower scores than AD subjects on visual memory, visuoperceptive, and visuoconstructive tests. No significant differences were found between PD‐d group and DLB subjects on any neuropsychological test. We were unable to find any differences in cognitive tasks between PD‐d and DLB subjects. Clinical features and neuropsychological deficiencies of DLB (attentional, visuoperceptive, and visuoconstructive deficits) and PD (attentional deficits) compared to AD (amnesic syndrome) can contribute to accurate identification of these entities and to the understanding of the neuropathological and neurochemical substrate underlying these diseases. © 2003 Movement Disorder Society
Spatial patterns of α‐synuclein positive glial cytoplasmic inclusions in multiple system atrophy
Authors: Armstrong Richard A. , Lantos Peter L. , Cairns Nigel J.
Published: January 2004

In cases of multiple system atrophy (MSA), glial cytoplasmic inclusions (GCI) were distributed randomly or present in large diffuse clusters (>1,600 μm in diameter) in most areas studied. These spatial patterns contrast with those reported for filamentous neuronal inclusions in the tauopathies and α‐synucleinopathies. © 2003 Movement Disorder Society
Michael J. Fox and his Parkinson's disease
Authors: Kempster Peter A.
Published: January 2004

Michael J. Fox was a popular and successful film and television comic actor who developed Parkinson's disease at the age of 29 years. His recently published book, Lucky Man, structured around the story of his Parkinson's disease, is an amusing, briskly paced yet introspective memoir that covers the first 40 years of his life. Although quite anecdotal, it contains interesting observations on the preclinical phase of the disorder, evolution of motor fluctuations, and tactics for pharmacological treatment. © 2003 Movement Disorder Society
Adverse effects of dopamine potentiation by long‐term treatment with selegiline
Authors: Hollán Susan , Vécsei László , Magyar Kálmán
Published: January 2004

A patient with triosephosphate isomerase (TPI) deficiency exhibited worsening of abnormal involuntary movements of the dystonic type and developed psychiatric symptoms while on selegiline. When selegiline was stopped after 9 years of treatment, abnormal involuntary movements improved to pretreatment level and psychiatric behaviour returned to normal. Monoamine oxidase‐B platelet activity was low in this patient. © 2003 Movement Disorder Society
Parkinsonism in Ontario: Comorbidity associated with hospitalization in a large cohort
Authors: Guttman Mark , Slaughter Pamela M. , Theriault Marc‐Erick , DeBoer Donald P. , Naylor C. David
Published: January 2004

To study comorbidity in patients with Parkinsonism (PKM), relative hospitalization rates from 1994 to 1999 for 15,304 cases were compared with 30,608 controls. After correction for differential survival, the rates were higher for cases compared to controls for aspiration pneumonia (6.34; 95% confidence interval [CI], 5.23, 7.93), affective psychosis (2.71; 95% CI, 2.13, 3.32), hip fractures (2.56; 95% CI, 2.35, 2.76), other urinary tract disorders including infections (2.5; 95% CI, 2.17, 2.86), septicemia (2.39; 95% CI, 2.02, 2.85) and fluid and electrolyte disorders (2.27; 95% CI, 1.93,2.66). The rates for cardiac, cerebrovascular, and peripheral vascular disease were similar. Preventive measures and aggressive management of these conditions as outpatients may reduce the rates of hospitalization and improve the morbidity and mortality of PKM. © 2003 Movement Disorder Society
Surgery in Tourette syndrome
Authors: Temel Yasin , Visser‐Vandewalle Veerle
Published: January 2004

Tourette syndrome (TS) is a neuropsychiatric disorder with onset in early childhood. It is characterized by tics and often accompanied by disturbances in behavior, such as obsessive–compulsive disorder (OCD). In most cases, the disorder is self‐limited or can be treated by medication or behavioral therapy. In a small percentage, however, symptoms are intractable to any conservative treatment. Since 1955, various attempts have been made to treat these patients through neurosurgical procedures. The target sites have been diverse and include the frontal lobe (prefrontal lobotomy and bimedial frontal leucotomy), the limbic system (limbic leucotomy and anterior cingulotomy), the thalamus, and the cerebellum. Combined approaches have also been tried such as anterior cingulotomies plus infrathalamic lesions. The results have often been unsatisfactory or major side effects have occurred, such as hemiplegia or dystonia. Our review of the literature from 1960 until 2003 revealed 21 reports and 3 descriptions in textbooks covering about 65 patients in total who had undergone ablative procedures for intractable TS, the first being reported in 1962. In 1999, deep brain stimulation (DBS) was introduced as a new approach for intractable TS. To date, 3 patients have been reported who underwent bilateral thalamic stimulation, with promising results on tics and obsessive‐compulsive symptoms. © 2003 Movement Disorder Society
Impaired modulation of the vestibulo‐ocular reflex in Huntington's disease
Authors: Fielding Joanne , Georgiou‐Karistianis Nellie , Bradshaw John , Millist Lynette , Churchyard Andrew , Chiu Edmond , White Owen
Published: January 2004

The vestibulo‐ocular reflex (VOR) stabilizes gaze during movement, in conjunction with other afferent information: visual, proprioceptive, and somaesthetic. The reflex can either be augmented or suppressed, depending on visual requirements, and undergoes long‐term adaptation to compensate for physical changes in the subject. Importantly, over relatively short periods of time, the VOR should function consistently under the same circumstances. This study examines VOR function in patients with Huntington's disease (HD), with a view to investigating cortical influences on the reflex. Horizontal eye movements were recorded in 9 patients with HD and 7 normal subjects, using the scleral search coil technique, in response to high frequency, unpredictable head rotations imposed manually. To establish base VOR function, recordings were made in darkness, without instruction, before and after wearing ×2 magnifying lenses for a period of 2 hours to adapt the reflex. Recordings were also made before adaptation, while fixating a stationary visual target (VOR augmentation), and while fixating a target moving with the head (VOR suppression). Although results suggest that the VOR is preserved in HD, with relatively normal gain values and appropriate augmentation and suppression of the reflex with visual input, patients were unable to adapt the VOR to altered visual conditions. This represents a novel finding in HD and suggests that cortical structures compromised in HD exert influences on the long‐term adaptation of the VOR. © 2003 Movement Disorder Society
Erratum
Authors: Remy Phillipe
Published: January 2004

The original article to which this Letter refers was published in the August issue of Movement DisordersMov Disord 2003;18(8):928–932.
Clarification: Pathogenic role of glial cells in Parkinson's disease
Authors: Przedborski Serge
Published: January 2004

The original article to which this Clarification refers was published in the February 2003 issue of Movement Disorders (Teismann P, Tieu K, Cohen O, Choi DK, Wu dC, Marks D, Vila M, Jackson‐Lewis V, Przedborski S. Pathogenic role of glial cells in Parkinson's disease. Mov Disord 2003;18:121–129.). © 2003 Movement Disorder Society
It's a double knock‐out! The quaking mouse is a spontaneous deletion of parkin and parkin co‐regulated gene (PACRG)
Authors: Lockhart Paul J. , O'Farrell Casey A. , Farrer Matthew J.
Published: January 2004

Mutations in the parkin gene (PRKN) are the commonest cause of juvenile and early‐onset parkinsonism. However, the pathogenic mechanism by which loss of parkin protein results in degeneration of dopaminergic neurons remains elusive. Animal models provide a useful tool for the study of development and disease, and the recent production of transgenic fly and mouse parkin deficient models allows investigation of the molecular role of parkin in dopamine regulation and nigrostriatal function. We have identified the mouse mutant Quaking as a spontaneously occurring PRKN knockout. The quaking mutation is a deletion of approximately 1.17 Mb of mouse chromosome 17, resulting in the deletion of the entire promoter and first five coding exons of PRKN In addition, the recently described Parkin Co‐Regulated Gene (PACRG) is completely deleted. Homozygous Quaking mice show a complete loss of PRKN and PACRG mRNA and protein. These mice will constitute a useful additional model for studies of the molecular role of parkin and PACRG in neurodegeneration. © 2003 Movement Disorder Society
Dynamic reallocation of capacity in logically fully‐connected networks
Authors: Chiera B. A. , Krieg M. R. , Parrott J. W. , Taylor P. G.
Published: January 2004

We study the benefits that can be realised when capacity reallocation schemes are implemented in telecommunications networks. Our basic model consists of a (possibly sparse) physical network above which is overlaid a logically fully‐connected network. This is achieved by reserving capacity on the physical links for exclusive use by each origin–destination pair. If the capacity allocated to the origin–destination pairs is fixed, then such a network is likely to produce poor performance due to restriction of multiplexing opportunities. However, this effect can be largely negated by employing a capacity reallocation scheme, where capacity is moved in a dynamic fashion to areas where congestion is occurring. For such a scheme to be scalable, it is essential that it be distributed in nature. In this paper, we present three distributed, dynamic capacity reallocation schemes and compare their performance using a simulation model. Copyright © 2004 John Wiley & Sons, Ltd.
Fast Uzawa algorithms for solving non‐symmetric stabilized saddle point problems
Authors: Cao Zhi‐Hao
Published: January 2004

Bramble et al. (Math. Comput. (2000); 69 (230) : 667–689) discussed the Uzawa type algorithms for iteratively solving nonsymmetric stable saddle point problems. In this paper, we consider the Uzawa type algorithms for iteratively solving generalized saddle point problems. Our main concern is how to accelerate the convergence of the inexact Uzawa type algorithms. The contributions of the paper are that a new non‐linear Uzawa type algorithm is presented and its convergence is analysed. Applications to Navier–Stokes equations by mixed finite element discretization with an unstable pair of approximation spaces, i.e. Q1‐P0 pair of approximation spaces, are discussed and the results of the numerical experiments of applying our new algorithm are presented. Copyright © 2003 John Wiley & Sons, Ltd.
BCCB preconditioners for systems of BVM‐based numerical integrators
Authors: Lei Siu‐Long , Jin Xiao‐Qing
Published: January 2004

Boundary value methods (BVMs) for ordinary differential equations require the solution of non‐symmetric, large and sparse linear systems. In this paper, these systems are solved by using the generalized minimal residual (GMRES) method. A block‐circulant preconditioner with circulant blocks (BCCB preconditioner) is proposed to speed up the convergence rate of the GMRES method. The BCCB preconditioner is shown to be invertible when the BVM is Ak1,k2‐stable. The spectrum of the preconditioned matrix is clustered and therefore, the preconditioned GMRES method converges fast. Moreover, the operation cost in each iteration of the preconditioned GMRES method by using our BCCB preconditioner is less than that required by using block‐circulant preconditioners proposed earlier. In numerical experiments, we compare the number of iterations of various preconditioners. Copyright © 2003 John Wiley & Sons, Ltd.
Partial pole assignment for the vibrating system with aerodynamic effect
Authors: Lin Wen‐Wei , Wang Jenn‐Nan
Published: January 2004

The partial pole assignment (PPA) problem is the one of reassigning a few unwanted eigenvalues of a control system by feedback to suitably chosen ones, while keeping the remaining large number of eigenvalues unchanged. The problem naturally arises in modifying dynamical behaviour of the system. The PPA has been considered by several authors in the past for standard state–space systems and for quadratic matrix polynomials associated with second‐order systems. In this paper, we consider the PPA for a cubic matrix polynomial arising from modelling of a vibrating system with aerodynamics effects and derive explicit formulas for feedback matrices in terms of the coefficient matrices of the polynomial. Our results generalize those of a quadratic matrix polynomial by Dattaet al. (Linear Algebra Appl. 1997;257: 29) and is based on some new orthogonality relations for eigenvectors of the cubic matrix polynomial, which also generalize the similar ones reported in Dattaet al. (Linear Algebra Appl. 1997;257: 29) for the symmetric definite quadratic pencil. Besides playing an important role in our solution for the PPA, these orthogonality relations are of independent interests, and believed to be an important contribution to linear algebra in its own right. Copyright © 2003 John Wiley & Sons, Ltd.
Stability of linear time‐periodic delay‐differential equations via Chebyshev polynomials
Authors: Butcher Eric A. , Ma Haitao , Bueler Ed , Averina Victoria , Szabo Zsolt
Published: January 2004

This paper presents a new technique for studying the stability properties of dynamic systems modeled by delay‐differential equations (DDEs) with time‐periodic parameters. By employing a shifted Chebyshev polynomial approximation in each time interval with length equal to the delay and parametric excitation period, the dynamic system can be reduced to a set of linear difference equations for the Chebyshev expansion coefficients of the state vector in the previous and current intervals. This defines a linear map which is the ‘infinite‐dimensional Floquet transition matrix U’. Two different formulas for the computation of the approximate U, whose size is determined by the number of polynomials employed, are given. The first one uses the direct integral form of the original system in state space form while the second uses a convolution integral (variation of parameters) formulation. Additionally, a variation on the former method for direct application to second‐order systems is also shown. An error analysis is presented which allows the number of polynomials employed in the approximation to be selected in advance for a desired tolerance. An extension of the method to the case where the delay and parametric periods are commensurate is also shown. Stability charts are produced for several examples of time‐periodic DDEs, including the delayed Mathieu equation and a model for regenerative chatter in impedance‐modulated turning. The results indicate that this method is an effective way to study the stability of time‐periodic DDEs. Copyright © 2004 John Wiley & Sons, Ltd.
A low‐order, hexahedral finite element for modelling shells
Authors: Key Samuel W. , Gullerud Arne S. , Koteras J. Richard
Published: January 2004

A thin, eight‐node, tri‐linear displacement, hexahedral finite element is the starting point for the derivation of a constant membrane stress resultant, constant bending stress resultant shell finite element. The derivation begins by introducing a Taylor series expansion for the stress distribution in the isoparametric co‐ordinates of the element. The effect of the Taylor series expansion for the stress distribution is to explicitly identify those strain modes of the element that are conjugate to the mean or average stress and the linear variation in stress. The constant membrane stress resultants are identified with the mean stress components, and the constant bending stress resultants are identified with the linear variation in stress through the thickness along with in‐plane linear variations of selected components of the transverse shear stress. Further, a plane‐stress constitutive assumption is introduced, and an explicit treatment of the finite element's thickness is introduced. A number of elastic simulations show the useful results that can be obtained (tip‐loaded twisted beam, point‐loaded hemisphere, point‐loaded sphere, tip‐loaded Raasch hook, and a beam bent into a ring). All of the gradient/divergence operators are evaluated in closed form providing unequivocal evaluations of membrane and bending strain rates along with the appropriate divergence calculations involving the membrane stress and bending stress resultants. The fact that a hexahedral shell finite element has two distinct surfaces aids sliding interface algorithms when a shell folds back on itself when subjected to large deformations. Published in 2004 by John Wiley & Sons, Ltd.
Moving particle finite element method with global smoothness
Authors: Hao Su , Liu Wing Kam , Belytschko Ted
Published: January 2004

We describe a new version of the moving particle finite element method (MPFEM) that provides solutions within a C0 finite element framework. The finite elements determine the weighting for the moving partition of unity. A concept of ‘General Shape Function’ is proposed which extends regular finite element shape functions to a larger domain. These are combined with Shepard functions to obtain a smooth approximation. The Moving Particle Finite Element Method combines desirable features of finite element and meshfree methods. The proposed approach, in fact, can be interpreted as a ‘moving partition of unity finite element method’ or ‘moving kernel finite element method’. This method possesses the robustness and efficiency of the C0 finite element method while providing at least C1 continuity. Copyright © 2004 John Wiley & Sons, Ltd.
Locating and retaining research participants for follow‐up studies
Authors: Lyons Karen S. , Carter Julie H. , Carter Emily H. , Rush Kirsten N. , Stewart Barbara J. , Archbold Patricia G.
Published: January 2004

Two common pitfalls of longitudinal research are loss of participants over time and inability to locate participants whose contact information has changed. This article is based on our experiences in locating and retaining a sample of caregivers of persons with Parkinson's disease 8–10 years after we last contacted them. The strategies we used resulted in locating 86% of our sample and retaining 80% of those who were eligible. These strategies included asking participants for a backup contact, asking participants if they would be willing to be contacted again for a future study, making the most of existing search engines, keeping in touch, and being flexible, patient, and professional. © 2004 Wiley Periodicals, Inc. Res Nurs Health 27:63–68, 2004
Quantitative analysis of mixtures of drug delivery system components by Raman microscopy
Authors: Szép A. , Marosi G. , Marosfői B. , Anna P. , Mohammed‐Ziegler I. , Virágh M.
Published: January 2004

A series of two‐component powders and tableted mixtures of corn starch and lactose‐monohydrate were prepared and studied using the fiber optic sensor of a LabRam dispersion Raman microscope in order to establish a convenient method for quantitative determination of their concentration based on Raman spectra. The intensities of certain characteristic peaks of the components were used for calculating the calibration curve. Linear calibration curves were found in the concentration range of 10–80% with correlation coefficients of 0.9979–0.9996 for powders and tablets. Chemical mapping of the tablets was also carried out, thus allowing determination of the distribution of the components. Copyright © 2003 John Wiley & Sons, Ltd.
Study of the kinetics of pyrolysis of a rigid polyurethane foam: use of the invariant kinetics parameters method
Authors: Lefebvre J. , Duquesne S. , Mamleev V. , Bras M. Le , Delobel R.
Published: January 2004

Among all of the methods used for the development and study of the degradation of a polymer, thermogravimetric analysis (TGA) is the most widespread. This study is interested in the modelling of the mass losses of rigid polyurethane foam under linear heating rates in an inert atmosphere using the Invariant Kinetic Parameters (IKP) method. The degradation of rigid polyurethane foam is a five‐stage process under a nitrogen atmosphere. The first stage of degradation has not been modelled because of too low a number of points. The model of potential law for the second stage, the model of reaction order for the third stage and a mixture of reaction order, phase‐boundary reaction and nucleation for the fourth stage are found to be the most adequate ones. Copyright © 2003 John Wiley & Sons, Ltd.
The modification of ultra‐high‐molecular‐weight polyethylene supramolecular structures induced by irradiation and thermal treatment
Authors: Nevoralová M. , Mikešová J. , Baldrian J. , Horák Z.
Published: January 2004

The effect of γ‐radiation and subsequent thermal treatment on the crystallinity and rheological characteristics of ultra‐high‐molecular‐weight polyethylene (UHMWPE) has been investigated. Irradiation of the polymer was performed using a 60Co γ‐emitter at laboratory temperatures. Five irradiation doses (25, 50, 100, 150 and 200 kGy), two dose rates (0.25 and 2.5 kGy/h) and two (atmosphereic environments) (air and nitrogen) were used. Some irradiated samples were thermally treated at 190°C. The crystallinity changes were determined using wide‐angle X‐ray diffraction (WAXS), while the rheological characteristics were measured with a rotation rheometer. In addition to the expected effect of γ‐rays on the structural changes and rheological behaviour of UHMWPE at higher radiation doses (from about 50 kGy), two interesting results were obtained. First, a minimum on the dependence of the radiation dose as a function of crystallinity was found for all of the measured samples. The crystallinity decrease in UHMWPE is also associated with substantial changes in its rheological properties at temperature above the melting point. Secondly, a remarkable effect of the dose rate on the measured characteristics has been proved. Copyright © 2003 John Wiley & Sons, Ltd.
Stereoregular polymerization of butyl vinyl ether using the new AlCl3/LiAlH4 initiator system
Authors: Nagy Miklós , Kéki Sándor , Deák György , Zsuga Miklós
Published: January 2004

The stereoregular polymerization of butyl vinyl ether (BVE) using the new AlCl3/LiAlH4 initiator system and a combination of these initiators with TiCl4 was investigated. Polymerization reactions were carried out at various temperatures ranging from 25°C to –60°C in diethyl ether, hexane, dichloromethane and in different mixtures of these solvents. The resulting polymers were characterized by 13C NMR spectroscopy, size‐exclusion chromatography (SEC) and matrix‐assisted laser desorption/ionization mass spectrometry (MALDI MS). The isotactic content of the polymers were determined from the 13C‐NMR spectra using the integral ratios of the signals of the methylene carbons. It was found that the isotactic polymer content increased with decreasing temperature until –40°C; however, below this temperature the isotactic content decreased considerably. The maximum isotactic polymer content was found to be 75% at –40°C in a mixture of hexane and diethyl ether (1/1 v/v). The dependence of the reaction rate and the isotactic polymer content on the solvent polarity was also studied. Copyright © 2003 John Wiley & Sons, Ltd.
Synthesis and investigation of the mechanical properties of poly(lactic acid)–(toluene diisocyanate)–poly(ethylene glycol)/poly(propylene glycol) copolymers
Authors: Borda Jenő , Bodnár Ildikó , Ráthy Istvánné , Zsuga Miklós
Published: January 2004

The synthesis and mechanical properties of the potentially biodegradable poly(lactic acid)–toluene diisocyanate–poly(ethylene glycol)/poly(propylene glycol) (PLA– TDI–PEG/PPG) copolymers were studied. There is a close connection between the optimal conditions of the synthesis and the mechanical properties, which were investigated in detail. The tensile characteristics of the copolymers were compared with those of commercially available foils. The carbon fiber reinforcement of these new biodegradable block copolymers is also reported. Copyright © 2003 John Wiley & Sons, Ltd.
Surface properties of poly(lactic/glycolic acid)–pluronic® blend films
Authors: Kiss É. , Takács M. G. , Bertóti I. , Vargha‐Butler E. I.
Published: January 2004

Poly(dl‐lactide) (PLA) and two of its random copolymers with glycolic acid, poly(dl‐lactide‐co‐glycolide) (PLGA) with 75/25 and 50/50 component ratios of lactide/glycolide were blended with poly(ethylene oxide)/poly(propylene oxide)/poly(ethylene oxide) (PEO–PPO–PEO) triblock non‐ionic surfactants, known by the Pluronic® trade names of PE6100, PE6400 and PE6800. The surface chemical compositions of the blended films were identified by X‐ray photoelectron spectroscopy (XPS). Based on the component of the carbon signal assigned to the ether carbon of the Pluronic® molecule, quantification of the surface accumulation of the Pluronic® additive, compared to its bulk concentration, was performed. The data demonstrated that PEO‐containing surfaces were prepared by the blending process. A significant surface hydrophilization, characterized by wettability measurements, was obtained by applying the Pluronics® at a concentration of 1.0–9.1 wt% in the blends. The composition of the surface layer and, in accordance with this, the wettability of the film were found to be dependent on the type of Pluronic® and on the composition of the unmodified polymer. Protein adsorption on the polymer films was measured by the FT‐IR ATR spectroscopic technique. The adsorbed amount of bovine serum albumin onto PLA was highly reduced when the polymer was blended with a Pluronic®. The increased hydrophilicity and the reduced protein adsorption properties of the PLA and PLGA obtained by blending with PEO compounds might contribute to their applications as drug carrier systems with great potential. Copyright © 2003 John Wiley & Sons, Ltd.
Modification of polymers by protein hydrolysate—A way to biodegradable materials
Authors: Saha Nabanita , Zatloukal Martin , Saha Petr
Published: January 2004

The increasing use of plastics and their non‐biodegradability have raised environmental awareness and hence the need for the development of environmently friendly degradable materials. One of the ways to reach this goal is via the modification of polymer with starch, cellulose, protein and other water‐soluble materials. This can also be achieved by protein hydrolysate (HP) which is a biopolymer isolated from the chrome‐tanned solid leather waste of the tanning industry by enzymatic hydrolysis. An investigation on the modification of metallocene‐based linear‐low‐density polyethylene (mLLDPE) with HP is reported. It is interesting to note that HP easily blends with mLLDPE but like other biopolymers it also reduces the original mechanical properties of the mLLDPE. Modification of the latter with 10% HP does not have much effect on the physical, mechanical and rheological behaviour. About 35% biodegradation is observed when the polymer is modified with 20 % HP and about 50% biodegradation is found in the case of polymer modified with 40% HP by Aspergillus oryzae (F‐172) under controlled laboratory conditions, at a temperature of 25°C and after a period of 21 days incubation in malt extract media. Although polymer films with 40% HP have shown better performance in biodegradation, the mechanical strength properties, however, are rather poor in this case. The optimum polymer film composition for modification of mLLDPE is 20% HP, which retains both an acceptable range of mechanical strength properties and biodegradability behaviour. Copyright © 2003 John Wiley & Sons, Ltd.
Role of inflammatory mediators in the pathophysiology of acute respiratory distress syndrome
Authors: Bhatia Madhav , Moochhala Shabbir
Published: January 2004

Inflammatory response leading to organ dysfunction and failure continues to be the major problem after injury in many clinical conditions such as sepsis, severe burns, acute pancreatitis, haemorrhagic shock, and trauma. In general terms, systemic inflammatory response syndrome (SIRS) is an entirely normal response to injury. Systemic leukocyte activation, however, is a direct consequence of a SIRS and if excessive, can lead to distant organ damage and multiple organ dysfunction syndrome (MODS). When SIRS leads to MODS and organ failure, the mortality becomes high and can be more than 50%. Acute lung injury that clinically manifests as acute respiratory distress syndrome (ARDS) is a major component of MODS of various aetiologies. Inflammatory mediators play a key role in the pathogenesis of ARDS, which is the primary cause of death in these conditions. This review summarizes recent studies that demonstrate the critical role played by inflammatory mediators such as tumour necrosis factor (TNF)‐α, interleukin (IL)‐1β, IL‐6, platelet activating factor (PAF), IL‐10, granulocyte macrophage‐colony stimulating factor (GM‐CSF), C5a, intercellular adhesion molecule (ICAM)‐1, substance P, chemokines, VEGF, IGF‐I, KGF, reactive oxygen species (ROS), and reactive nitrogen species (RNS) in the pathogenesis of ARDS. It is reasonable to speculate that elucidation of the key mediators in ARDS coupled with the discovery of specific inhibitors would make it possible to develop clinically effective anti‐inflammatory therapy. Copyright © 2004 John Wiley & Sons, Ltd.
Gastric mucosal cytokine and epithelial cell responses to Helicobacter pylori infection in Mongolian gerbils
Authors: Crabtree Jean E , Court Michelle , Aboshkiwa Mohamed A , Jeremy Anthony HT , Dixon Michael F , Robinson Philip A
Published: January 2004

Experimental infection with Helicobacter pylori in Mongolian gerbils results in chronic gastritis and gastric cancer. To investigate epithelial cell proliferation, apoptosis, and mucosal cytokine responses in gastritis, Mongolian gerbils were infected with the H pylori SS1 strain. At 4 weeks post‐infection, gastritis was predominantly within the antrum, but extended to the corpus in approximately 50% of gerbils by 36 weeks. Epithelial cell proliferation and apoptosis in glandular epithelial cells were increased with infection. Antral cell proliferation, but not apoptosis, correlated significantly with gastric inflammation. In female gerbils, H pylori significantly increased expression of transcripts for IFN‐γ and IL‐12p40, but not TGF‐β or IL‐10, in the gastric mucosa. Significantly reduced IFN‐γ and IL‐12p40 responses were observed in male gerbils infected with H pylori, but epithelial proliferative and apoptotic responses were comparable to those of females. These studies demonstrate that the female gerbil cytokine response to H pylori has a Th1 profile and that there are gender differences in the magnitude of the gastric cytokine responses to H pylori. The absence of a down‐regulatory cytokine response may account for the more severe gastritis observed with H pylori infection in gerbils than in mice. Copyright © 2004 John Wiley & Sons, Ltd.
Expression of BUB1 protein in gastric cancer correlates with the histological subtype, but not with DNA ploidy or microsatellite instability
Authors: Grabsch Heike I , Askham Jon M , Morrison Ewan E , Pomjanski Natalja , Lickvers Kristina , Parsons Wendy J , Boecking Alfred , Gabbert Helmut E , Mueller Wolfram
Published: January 2004

During mitosis, the spindle checkpoint delays the onset of anaphase until all chromosomes have attached properly to the mitotic spindle, preventing chromosome missegregation. BUB (budding uninhibited by benzimidazole) 1 is one of the key components of this checkpoint. BUB1 mutations are rare in cancer tissues and no mutations have been identified in gastric cancer. In mice, immunodepletion of BUB1 abolished the spindle checkpoint. Thus, aberrant expression of BUB1 protein could impair mitotic checkpoint function, resulting in aneuploidy, a common phenomenon in gastric cancer. In the present study, an antibody was generated against BUB1 and its expression was studied in gastric cancer tissue sections (n = 80) by immunohistochemistry. Nuclear BUB1 expression was found in all gastric cancer cases. The proportion of tumour cells expressing BUB1 was significantly greater in diffuse‐type than in intestinal‐type gastric carcinoma (p < 0.001). No correlation was found between BUB1 expression and deoxyribonucleic acid (DNA) ploidy, microsatellite instability or any other histopathological parameters investigated. To the authors' knowledge, this is the first study of BUB1 protein expression in gastric cancer tissues. Different BUB1 protein expression levels in intestinal‐ and diffuse‐type gastric cancer may provide further evidence of a potential link between different genetic pathways and morphological phenotype in gastric carcinogenesis. However, further studies are needed to establish whether there is an association between BUB1 protein expression level and mitotic spindle checkpoint function in gastric cancer. Copyright © 2004 John Wiley & Sons, Ltd.
Emphysema: the challenge of the remodelled lung
Authors: Blundell R , Harrison DJ , Wallace WAH
Published: January 2004

Emphysema is recognized as the component of chronic obstructive airways disease that is responsible for airways obstruction. Different patterns of emphysema are, however, recognized, suggesting possible different pathogenetic processes within the lung. This, coupled with the associated idea of susceptibility factors to the development of emphysema, has led to studies of genes that may be involved in the defence of the lung from proteolytic and oxidative damage. These studies have been driven by the goal of finding a treatment for emphysema, but appear to have lost sight of the fundamental remodelling of the lung that has occurred in patients with emphysema and the fact that it is not a single morphological entity. Copyright © 2004 John Wiley & Sons, Ltd.
Expression of acyl‐CoA synthetase 5 reflects the state of villus architecture in human small intestine
Authors: Gassler Nikolaus , Kopitz Jürgen , Tehrani Arman , Ottenwälder Birgit , Schnölzer Martina , Kartenbeck Jürgen , Lyer Stefan , Autschbach Frank , Poustka Annemarie , Otto Herwart F , Mollenhauer Jan
Published: January 2004

Several disorders of the small intestine are associated with disturbances in villus architecture. Thus, an understanding of the molecular mechanisms associated with the differentiation of villi represents an important step in the improvement of the understanding of small intestinal pathology. Screening of antibodies from a hybridoma library led to the identification of an acyl‐CoA synthetase 5‐specific monoclonal antibody. Protein synthesis, mRNA expression, and the enzyme activity of acyl‐CoA synthetase 5 were studied by several methods in human small intestinal tissues with Crohn's disease or coeliac disease, respectively. Acyl‐CoA synthetase 5 mRNA and protein levels were substantially reduced in injured small intestinal mucosa. Moreover, impaired synthesis of the acyl‐CoA synthetase 5 protein was reflected by a decrease in intramucosal enzyme activity. Subtle changes of the acyl‐CoA synthetase 5 pattern correlate with conversion of intestinal epithelial cells to a gastric phenotype. These results suggest that deranged acyl‐CoA synthetase 5 expression, synthesis, and activity are closely related to the state of villus architecture and epithelial homeostasis in human small intestine. Copyright © 2004 John Wiley & Sons, Ltd.
The human Delta‐like 1 homologue is implicated in the progression of liver fibrosis in biliary atresia
Authors: Huang Chao‐Cheng , Chuang Jiin‐Haur , Huang Lynn LH , Chou Ming‐Huei , Wu Chia‐Lin , Chen Ching‐Mei , Hsieh Chie‐Song , Lee Shin‐Ye , Chen Chao‐Long
Published: January 2004

Advanced liver cirrhosis frequently occurs in infants with biliary atresia despite early surgical correction. The aetiology is unknown, but may involve many cytokines and liver cells including hepatic stellate cells (HSCs). A cytokine expression array and real‐time quantitative reverse transcription‐polymerase chain reaction (QRT‐PCR) were used to study cytokine expression during the progression of liver fibrosis in biliary atresia. A Delta‐like 1 homologue (DLK1) gene was identified and this gene was up‐regulated during the early stage, and down‐regulated during the late stage, of biliary atresia, similar to the expression pattern of the procollagen α1(I) gene. Further characterization with immunohistochemistry, confocal microscopy, and in situ hybridization revealed that the DLK1 protein was mainly present in the cytoplasm of smooth muscle actin‐positive mesenchymal cells that were morphologically and immunohistochemically identical to activated HSCs/myofibroblasts, whereas DLK1 mRNA was present only in hepatocytes. As DLK1 is a negative regulator of adipocyte differentiation and may control cell fate during differentiation, overexpression of DLK1 protein in HSCs in the early stage of biliary atresia suggests that DLK1 may be implicated in the transformation of HSCs from fat‐storing cells to myofibroblasts and in fibrogenesis associated with biliary atresia. Copyright © 2004 John Wiley & Sons, Ltd.
Disrupted traffic of connexin 43 in human testicular seminoma cells: overexpression of Cx43 induces membrane location and cell proliferation decrease
Authors: Roger C , Mograbi B , Chevallier D , Michiels JF , Tanaka H , Segretain D , Pointis G , Fenichel P
Published: January 2004

Connexins, the constitutive proteins of gap junctions, are considered to be tumour suppressive agents and are often impaired in the tumourigenic processes. In the present study, the expression of connexin 43 (Cx43), which is involved in the control of spermatogenesis through Sertoli/germ cell coupling, has been investigated in human testicular seminoma cells (tumours and the JKT‐1 cell line). Cx43 was immunolocalized in the Golgi apparatus without membrane expression and was detected by immunoblotting in JKT‐1 as exclusive 70 kD bands. No mutation could be found by sequencing the transcript obtained by RT‐PCR. Transfection with a Cx43‐V5 vector reproduced the same gel shift, identifying these 70 kD bands as Cx43. The Cx43‐70 kD bands were also expressed in normal testicular tissue, associated with the classical 43 kD isoforms. Stable transfection of JKT‐1 with a Cx43‐GFP vector allowed restoration of Cx43 membrane expression, functional cell coupling, and inhibition of the cell proliferation rate. Storage of Cx43 in the Golgi apparatus may correspond during spermatogenesis to an intermittent physiological process that becomes permanent in malignant seminoma cells as a result of the tumourigenic process. By preventing Cx43 membrane expression, this disrupted traffic may itself participate in tumour promotion. Copyright © 2004 John Wiley & Sons, Ltd.
BRAF mutations are associated with some histological types of papillary thyroid carcinoma
Authors: Trovisco Vítor , Vieira de Castro Inês , Soares Paula , Máximo Valdemar , Silva Paula , Magalhães João , Abrosimov Alexander , Guiu Xavier Matias , Sobrinho‐Simões Manuel
Published: January 2004

Mutations in the BRAF gene have recently been detected in a wide range of neoplastic lesions with a particularly high prevalence in melanoma and papillary thyroid carcinoma (PTC). The hot‐spot mutation BRAFV599E is frequently detected in PTC (36–69%), in contrast to its absence in other benign or malignant thyroid lesions. In order to unravel whether there is any association between the occurrence of the BRAF mutation and the histological pattern of PTC, in this study a previous series of 50 PTCs was extended to 134 cases, including ten cases of PTC‐related entities—hyalinizing trabecular tumour (HTT) and mucoepidermoid carcinoma (MEC). Using PCR/SSCP and sequencing, the BRAFV599E mutation was detected in 45 of the 124 PTCs (36%). No mutations were detected in any case of HTT and MEC. BRAFV599E was present in 75% of Warthin‐like PTCs and 53% of conventional PTCs, whereas no BRAFV599E mutations were detected in any of the 32 cases of the follicular variant of PTC. BRAFV599E was also detected in 6 of 11 cases of the oncocytic variant of PTC that displayed a papillary or mixed follicular–papillary growth pattern and in none of the four oncocytic PTCs with a follicular growth pattern. A distinct mutation in BRAF (codon K600E) was detected in three cases of the follicular variant of PTC. This study has confirmed the high prevalence of BRAFV599E in PTC and has shown that the mutation is almost exclusively seen in PTC with a papillary or mixed follicular–papillary growth pattern, regardless of the cytological features of the neoplastic cells. The results support the existence of an oncocytic variant of PTC that should be separated from the oncocytic variant of follicular carcinoma and suggest that the follicular variant of PTC may be genetically different from conventional PTC. Copyright © 2004 John Wiley & Sons, Ltd.