bluuebunny/crossref_metadata_2025_split huggingface dataset:
Morphological color changes in fish: Regulation of pigment cell density and morphology
Authors: Sugimoto Masazumi 
Published: October 2002

AbstractPigment cells enable fish to change their coloration. It has been recognized that fish color changes can be divided into two categories; one is a physiological color change, which is attributed to rapid motile responses of chromatophores, and the other is a morphological color change, which results from changes in the morphology and density of chromatophores. Long‐term adaptation of fish to a certain background can be a general cue to morphological color changes, and has been studied from the beginning of the 19th century. Although the motile mechanism and its control in fish chromatophores are now being elucidated, it is not yet clear how chromatophores change their density and what controls morphological color changes. In recent years, chromatophores, especially melanophores, have been shown to differentiate and to die by apoptosis under the influence of factors that regulate motile responses. Those factors are likely to utilize common intracellular signaling pathways used in part to regulate both types of color changes. In this article, after briefly reviewing the history of early studies, recent findings are discussed relevant to increases or decreases in chromatophores, and changes in their morphology. Finally, morphological color changes are discussed as physiological phenomena involved in the balance between differentiation and apoptosis of chromatophores. Microsc. Res. Tech. 58:496–503, 2002. © 2002 Wiley‐Liss, Inc.
Protein kinases in mammary gland development and cancer
Authors: Kumar Rakesh , Wang Rui‐An 
Published: October 2002

AbstractProtein kinases, the enzymes responsible for phosphorylation of a wide variety of proteins, are the largest class of genes known to regulate growth, development, and neoplastic transformation of mammary gland. Mammary gland growth and maturation consist of a series of highly ordered events involving interactions among several distinct cell types that are regulated by complex interactions among many steroid hormones and growth factors. The mammary gland is one of the few organ systems in mammals that complete their morphologic development postnatally during two discrete physiologic states, puberty and pregnancy. Thus, the mammary gland is an excellent model for studying normal development and the early steps of tumor formation. The susceptibility of the mammary gland to tumorigenesis is influenced by its normal development, particularly during stages of puberty and pregnancy. Numerous experimental and epidemiological studies have suggested that specific details in the development of the mammary gland play a critical role in breast cancer risk. Mammary gland development is characterized by dynamic changes in the expression and functions of protein kinases. Perturbations in the regulated expression or function of protein kinases or their associated signaling pathways can lead to malignant transformation of the breast. For example, overexpression of several receptor‐tyrosine kinases, including human epidermal growth factor receptor and HER2/Neu, has been shown to contribute to the development of breast cancer. Since receptor‐tyrosine kinases regulate several essential processes such as mitogenesis, motility, invasion, cell survival, and angiogenesis, targeting receptor‐tyrosine kinases may have important implications in designing strategies against breast cancer. Microsc. Res. Tech. 59:49–57, 2002. © 2002 Wiley‐Liss, Inc.
It's not just about anatomy: In vivo bioluminescence imaging as an eyepiece into biology
Authors: Contag Christopher H. , Ross Brian D. 
Published: October 2002

AbstractAmong the newly described tools that enable analyses of cellular and molecular events in living animals, in vivo bioluminescence imaging (BLI) offers important opportunities for investigating a wide variety of disease processes. BLI utilizes luciferase as an internal biological light source that can be genetically programmed to noninvasively “report” the presence or activation of specific biological events. Applications of BLI have included the use of luciferase to demonstrate expression of cell‐ and tissue‐specific promoters, label cell populations, guide detection by other imaging modalities, and detect protein‐protein interaction. These applications of BLI technology have allowed quantitative measurements of tumor burden and treatment response, immune cell trafficking, and detection of gene transfer. Spatiotemporal information can be rapidly obtained in the context of whole biological systems in vivo, which can accelerate the development of experimental therapeutic strategies. This paper provides a review of the biological applications in which in vivo BLI has been utilized to nondestructively monitor biological processes in intact small animal models, and highlights some of the advancements that will increase the versatility of BLI as a molecular imaging tool. J. Magn. Reson. Imaging 2002;16:378–387. © 2002 Wiley‐Liss, Inc.
Insights into the use of paramagnetic Gd(III) complexes in MR‐molecular imaging investigations
Authors: Aime Silvio , Cabella Claudia , Colombatto Sebastiano , Geninatti Crich Simonetta , Gianolio Eliana , Maggioni Fabio 
Published: October 2002

AbstractCan gadolinium III [Gd(III)] complexes be considered good candidates for magnetic resonance (MR)‐molecular imaging studies? In this review article, we examine the principal issues that are the basis of successful use of Gd‐based protocols in molecular imaging applications. High relaxivity is the primary requisite. Therefore, the design of such paramagnetic probes has to be pursued keeping in mind the relationships between structure, dynamics, and the relevant parameters involved in paramagnetic relaxation processes. Moreover, the limited number of target molecules on cellular membranes makes it necessary to define strategies aimed at delivering many Gd‐containing moieties to the sites of interest. Examples are reported for the attainment of very high relaxivities for the design of new routes for pursuing the accumulation of small sized Gd(III) complexes at the targeting sites. An efficient cellular uptake of Gd‐containing probes is the key step for attaining the visualization of targeted cells by MR imaging, and selected examples are reported. In this context, the problem of the assessment of the minimum amount of Gd(III) complexes necessary for the MR imaging‐visualization of cells has been addressed by reporting the authors' observations on the cell‐internalization of Gd(III) complexes. A particularly efficient delivery system is represented by Gd‐loaded apoferritin, which allows the MR visualization of hepatocytes when the number of Gd‐complexes per cell is 4 ± 1 × 107. Finally, the potential of responsive systems is considered by outlining the exploitation of the amplification effect brought about by the action of a specific enzymatic activity on the relaxivity of a suitably functionalized Gd(III) complex. J. Magn. Reson. Imaging 2002;16:394–406. © 2002 Wiley‐Liss, Inc.
A stable subcell model for arbitrarily oriented thin wires for the FDTD method
Authors: Ledfelt G. 
Published: October 2002

AbstractThin‐wire subcell models are widely used to allow the FDTD method to take wires thinner than the cell size into account. In this paper, a subcell model is generalized to handle arbitrarily oriented thin wires in an accurate way. The coupling of the Maxwell equations and the wire equations is discussed in detail. Stability of the subcell model is also shown and results for dipole antennas and loop antennas illustrates the performance of the new subcell model. Copyright © 2002 John Wiley & Sons, Ltd.
Time‐domain prediction of the radiated susceptibility in a shielded cable inside a penetrable shielded box
Authors: Feliziani Mauro , Maradei Francescaromana 
Published: October 2002

AbstractThe radiated susceptibility of a shielded cable inside a penetrable shielded enclosure is analysed by a numerical procedure based on the finite‐difference time‐domain (FDTD) method. Impedance network boundary conditions (INBCs) are used to model the field penetration through the shield. The induced effects of the field‐excited shielded cable are analysed by using a hybrid technique based on the FDTD method and on the multiconductor transmission line (MTL) model. Application examples are given. Copyright © 2002 John Wiley & Sons, Ltd.
Gene expression profiling in developing human hippocampus
Authors: Zhang Yan , Mei Pinchao , Lou Rong , Zhang Michael Q. , Wu Guanyun , Qiang Boqin , Zhang Zhengguo , Shen Yan 
Published: October 2002

AbstractThe gene expression profile of developing human hippocampus is of particular interest and importance to neurobiologists devoted to development of the human brain and related diseases. To gain further molecular insight into the developmental and functional characteristics, we analyzed the expression profile of active genes in developing human hippocampus. Expressed sequence tags (ESTs) were selected by sequencing randomly selected clones from an original 3′‐directed cDNA library of 150‐day human fetal hippocampus, and a digital expression profile of 946 known genes that could be divided into 16 categories was generated. We also used for comparison 14 other expression profiles of related human neural cells/tissues, including human adult hippocampus. To yield more confidence regarding differential expression, a method was applied to attach normalized expression data to genes with a low false‐positive rate (<0.05). Finally, hierarchical cluster analysis was used to exhibit related gene expression patterns. Our results are in accordance with anatomical and physiological observations made during the developmental process of the human hippocampus. Furthermore, some novel findings appeared to be unique to our results. The abundant expression of genes for cell surface components and disease‐related genes drew our attention. Twenty‐four genes are significantly different from adult, and 13 genes might be developing hippocampus‐specific candidate genes, including wnt2b and some Alzheimer's disease‐related genes. Our results could provide useful information on the ontogeny, development, and function of cells in the human hippocampus at the molecular level and underscore the utility of large‐scale, parallel gene expression analyses in the study of complex biological phenomena. © 2002 Wiley‐Liss, Inc.
Functional expression of CCR2 by human fetal astrocytes
Authors: Andjelkovic Anuska V. , Song Li , Dzenko Kirk A. , Cong Hui , Pachter Joel S. 
Published: October 2002

AbstractAstrocytes from different sources bind the chemokine monocyte chemoattractant factor (MCP‐1), yet functional expression in these cells of CCR2, the major receptor for this ligand, has been a matter of controversy. Here we show that cultured human fetal astrocytes express CCR2 at the mRNA and protein levels, and display chemotaxis and calcium flux in response to MCP‐1. Surface CCR2 protein expression and MCP‐1 binding activity were observed to undergo near parallel downmodulation and recovery following MCP‐1 exposure, supporting the argument that CCR2, and not another receptor, mediates MCP‐1 ligation in these cells. Downmodulation was further determined to occur via receptor internalization, and to apparently proceed via both clathrin‐coated vesicles and caveolae, the latter being a novel mode for the endocytosis of chemokine receptors. Insofar as MCP‐1 is thought to mediate inflammatory and developmental processes within the central nervous system (CNS), such astrocyte responses to this chemokine are likely to significantly impact physiological and pathophysiological events at the blood‐brain barrier and within the CNS parenchyma. © 2002 Wiley‐Liss, Inc.
Glutamate‐dependent transcriptional regulation of the chkbp gene: Signaling mechanims
Authors: Aguirre Adán , López‐Bayghen Esther , Ortega Arturo 
Published: October 2002

AbstractGlutamate, the major excitatory neurotransmitter, induces a signal from the membrane to the nucleus that regulates gene expression. The gene encoding the chick kainate binding protein undergoes a glutamate‐dependent transcriptional regulation via an activator protein‐1 site within its promoter region. To characterize this event, cultured chick Bergmann glia cells were exposed to glutamate, and a dose‐dependent increase in promoter activity was established. The glutamate effect is mediated through Ca2+‐permeable α‐amino‐3‐hydroxy‐5‐methyl‐4‐isoxazolepropionic acid/kainate receptors. The signaling cascade includes phosphatidyl inositol 3‐kinase, Ca2+/calmodulin‐dependent protein kinase II, mitogen‐activated protein kinase, and p90 ribosomal S6 kinase activation. The cAMP response‐element binding protein becomes phosphorylated and activates fos transcription. Finally, the activator protein‐1 complex binds to the glutamate response element in the chick kainate binding protein promoter region inducing its activity. We propose that the mitogen‐activated protein kinase/p90 ribosomal S6 kinase pathway plays a critical role in glutamate‐induced gene transcription. © 2002 Wiley‐Liss, Inc.
Micromechanical analysis of silicon nitride: a comparative study by fracture mechanics and Raman microprobe spectroscopy
Authors: Tochino Shigemi , Pezzotti Giuseppe 
Published: October 2002

AbstractRaman microprobe spectroscopy was used to characterize in situ microstress fields which develop during fracture of a toughened silicon nitride (Si3N4) polycrystal. Maps of microscopic stress were collected in the neighborhood of a propagating crack both at zero and at critical loading conditions. Micromechanics results by Raman spectroscopy were analyzed and compared with conventional fracture mechanics assessments, such as the evaluation of rising R‐curve behavior and crack opening displacement. Outcomes of these assessments illustrate that, despite the approximations involved in the piezo‐spectroscopic equations used for calculating the microstress field from a local Raman shift, Raman microprobe spectroscopy is a viable method for semi‐quantitative investigations of microfracture mechanisms in advanced ceramic materials. Copyright © 2002 John Wiley & Sons, Ltd.
Anthocyanins in fruits of Prunus padus (bird cherry)
Authors: Kucharska Alicja Z , Oszmiański Jan 
Published: October 2002

AbstractBird cherry (Prunus padus) anthocyanins were extracted with acidified methanol, fractionated by column chromatography on Toyopearl HW40(S) and purified in a C‐18 Sep‐Pak cartridge. The pigment composition was very simple, as there were only two compounds. The anthocyanins cyanidin‐3‐rutinoside (60%) and cyanidin‐3‐glucoside (40%) were determined using chromatographic and spectroscopic methods.© 2002 Society of Chemical Industry
An experimental paradigm for studying the cellular and molecular mechanisms of cancer inhibition by energy restriction
Authors: Zhu Zongjian , Jiang Weiqin , Thompson Henry J. 
Published: October 2002

AbstractWith a rapid‐emergence, chemically induced animal model for breast cancer, an experiment designed to test the hypothesis that energy restriction (ER) induces the loss of carcinogen‐initiated cells from the mammary gland, thereby conferring a permanent protective effect against the development of cancer, failed to support this hypothesis. Nonetheless, this experiment served to define an experimental approach and a time frame on which to focus mechanistic inquiry. With an ER and energy repletion (ER‐REP) protocol as a tool for identifying potential mediators of the cancer‐inhibitory activity of ER, concomitant changes in plasma corticosterone and insulin‐like growth factor 1 during energy restriction and repletion were observed. The relationship of the timing of these hormonal changes to the time frame of change in the carcinogenic response during ER‐REP was consistent with the role of both hormones in mediating the protective effects of ER. However, a similar pattern of change in the energy‐regulated hormone leptin indicated that its role in cancer inhibition also merits consideration. © 2002 Wiley‐Liss, Inc.
Anticardiolipin antibody in vascular parkinsonism
Authors: Huang Zhigao , Jacewicz Michael , Pfeiffer Ronald F. 
Published: October 2002

AbstractVascular parkinsonism (VP) is characterized by predominantly lower body involvement with gait impairment and postural instability, often without tremor, and by relative levodopa unresponsiveness. Neuroimaging studies demonstrate multiple infarcts or ischemic changes in periventricular white matter. Anticardiolipin antibodies (ACLA) are associated with hypercoagulable states and increased stroke risk. Review of our Movement Disorders Clinic records identified 44 individuals with a diagnosis of VP. ACLA have been obtained in 22 of these patients (mean age, 78.3 years; mean Mini‐Mental Status Exam score, 25.8). Gait disturbance was the initial clinical feature in 82% of the patients, and levodopa responsiveness was present in 18% of those treated. In 9 of the 22 (40.9%), ACLA immunoglobulin G was positive. No significant differences in clinical features or risk factors (hypertension, diabetes, coronary artery disease, and clinical stroke) were evident between ACLA+ and ACLA− groups. Since the presence of ACLA in individuals with stroke is usually treated by full‐scale anticoagulation with warfarin, our findings raise the question whether such treatment should also be used in persons with VP who are ACLA positive. © 2002 Movement Disorder Society
Quantitative description of loss of clinical benefit following withdrawal of levodopa–carbidopa and bromocriptine in early Parkinson's disease
Authors: Hauser Robert A. , Holford Nicholas H.G. 
Published: October 2002

AbstractIn Parkinson's disease, effects of medications on the progression of the underlying disease can be assessed clinically by evaluating patients at baseline prior to treatment and at endpoint following medication washout. With this design, it is critical to employ a washout of sufficient duration to ensure elimination of all symptomatic effects. To assess the time course of resolution of symptomatic effects, we evaluated 31 patients with early Parkinson's disease for 2 weeks following discontinuation of levodopa–carbidopa and bromocriptine after 14 months of treatment. Patients had previously been randomly assigned to treatment with selegiline or placebo, and these had been discontinued 2 months earlier. Data from 20 patients with a clear washout of clinical benefit were used to investigate quantitative models describing the time course of total (Activities of Daily Living + motor) Unified Parkinson's Disease Rating Scale score change. The mean half‐life of loss of clinical benefit was 7.9 days (95% confidence interval, 2.2–30.4 days). This indicates that a washout period of 32 days (4 half‐lives) may be required to eliminate approximately 90% of the long‐term symptomatic effects of levodopa–carbidopa and bromocriptine following their withdrawal from patients with early Parkinson's disease. © 2002 Movement Disorder Society
New anti‐HIV agents and targets
Authors: Clercq Erik De 
Published: October 2002

AbstractVirtually all the compounds that are currently used or are subject of advanced clinical trials for the treatment of HIV infections, belong to one of the following classes: (i) nucleoside reverse transcriptase inhibitors (NRTIs): i.e., zidovudine, didanosine, zalcitabine, stavudine, lamivudine, abacavir, emtricitabine and nucleotide reverse transcriptase inhibitors (NtRTIs) (i.e., tenofovir disoproxil fumarate); (ii) non‐nucleoside reverse transcriptase inhibitors (NNRTIs): i.e., nevirapine, delavirdine, efavirenz, emivirine; and (iii) protease inhibitors (PIs): i.e., saquinavir, ritonavir, indinavir, nelfinavir, amprenavir, and lopinavir. In addition to the reverse transcriptase and protease reaction, various other events in the HIV replicative cycle can be considered as potential targets for chemotherapeutic intervention: (i) viral adsorption, through binding to the viral envelope glycoprotein gp120 (polysulfates, polysulfonates, polycarboxylates, polyoxometalates, polynucleotides, and negatively charged albumins); (ii) viral entry, through blockade of the viral coreceptors CXCR4 (i.e., bicyclam (AMD3100) derivatives) and CCR5 (i.e., TAK‐779 derivatives); (iii) virus–cell fusion, through binding to the viral envelope glycoprotein gp41 (T‐20, T‐1249); (iv) viral assembly and disassembly, through NCp7 zinc finger‐targeted agents [2,2′‐dithiobisbenzamides (DIBAs), azadicarbonamide (ADA)]; (v) proviral DNA integration, through integrase inhibitors such as 4‐aryl‐2,4‐dioxobutanoic acid derivatives; (vi) viral mRNA transcription, through inhibitors of the transcription (transactivation) process (flavopiridol, fluoroquinolones). Also, various new NRTIs, NNRTIs, and PIs have been developed that possess, respectively: (i) improved metabolic characteristics (i.e., phosphoramidate and cyclosaligenyl pronucleotides by‐passing the first phosphorylation step of the NRTIs), (ii) increased activity [“second” or “third” generation NNRTIs ( i.e., TMC‐125, DPC‐083)] against those HIV strains that are resistant to the “first” generation NNRTIs, or (iii), as in the case of PIs, a different, modified peptidic (i.e., azapeptidic (atazanavir)) or non‐peptidic scaffold (i.e., cyclic urea (mozenavir), 4‐hydroxy‐2‐pyrone (tipranavir)). Non‐peptidic PIs may be expected to inhibit HIV mutant strains that have become resistant to peptidomimetic PIs. © 2002 Wiley Periodicals, Inc. Med Res Rev, 22, No. 6, 531–565, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/med.10021
High angular resolution diffusion imaging reveals intravoxel white matter fiber heterogeneity
Authors: Tuch David S. , Reese Timothy G. , Wiegell Mette R. , Makris Nikos , Belliveau John W. , Wedeen Van J. 
Published: October 2002

AbstractMagnetic resonance (MR) diffusion tensor imaging (DTI) can resolve the white matter fiber orientation within a voxel provided that the fibers are strongly aligned. However, a given voxel may contain a distribution of fiber orientations due to, for example, intravoxel fiber crossing. The present study sought to test whether a geodesic, highb‐value diffusion gradient sampling scheme could resolve multiple fiber orientations within a single voxel. In regions of fiber crossing the diffusion signal exhibited multiple local maxima/minima as a function of diffusion gradient orientation, indicating the presence of multiple intravoxel fiber orientations. The multimodality of the observed diffusion signal precluded the standard tensor reconstruction, so instead the diffusion signal was modeled as arising from a discrete mixture of Gaussian diffusion processes in slow exchange, and the underlying mixture of tensors was solved for using a gradient descent scheme. The multitensor reconstruction resolved multiple intravoxel fiber populations corresponding to known fiber anatomy. Magn Reson Med 48:577–582, 2002. © 2002 Wiley‐Liss, Inc.