bluuebunny/crossref_metadata_2025_split huggingface dataset:
Expression profiles of EphA3 at both the RNA and protein level in the developing mammalian forebrain
Authors: Kudo Chikako , Ajioka Itsuki , Hirata Yukio , Nakajima Kazunori 
Published: May 2005

AbstractThe ephrin/Eph system is well known to regulate various aspects of brain development. In this study, we analyzed the expression profiles of EphA3 at both the RNA and protein level in developing mouse forebrains. Although the EphA3 gene is known to encode two isoforms of the receptors, a full‐length transmembrane form, and a short, secretory form, only the full‐length isoform was detected in the developing forebrain. We found that, in the early developmental stages, while EphA3 mRNA was expressed in the dorsal thalamus and the cortical intermediate zone (IMZ), the EphA3 protein was detected in the IMZ and the internal capsule, but not in the dorsal thalamus. In the later stages the mRNA was expressed in the most superficial region of the cortical plate, while the protein was expressed in the IMZ. This discrepancy between the mRNA and protein expression patterns might be attributed to the possibility of the protein being transported to the axons to regulate the thalamocortical and corticofugal projection. The results of double‐immunostaining for L1 and EphA3 or TAG‐1 and EphA3 suggested that EphA3 protein was produced mainly in the thalamocortical axons and only partially in the corticofugal axons. In addition, the EphA3 protein was also detected in various other structures, such as the lateral olfactory tract, anterior commissure, and corpus callosum, suggesting the possibility that EphA3 might regulate the formation of various neuronal networks in the developing brain, including the TC projection and the commissural fibers. J. Comp. Neurol. 487:255–269, 2005. © 2005 Wiley‐Liss, Inc.
Energy Flow in Push–Pull Chromophores: Vibrational Dynamics in para‐Nitroaniline
Authors: Gunaratne Tissa , Challa J. Reddy , Simpson M. Cather 
Published: May 2005

Abstractpara‐Nitroaniline (PNA) plays an essential role as the prototype model of push–pull chromophores. The nature and degree of participation of vibrational degrees of freedom in the charge‐transfer and internal‐conversion processes are current issues of great theoretical and practical importance. Ultrafast time‐resolved anti‐Stokes resonance Raman spectroscopy (TRARRS) experiments on PNA in dimethyl sulfoxide with three different excitation wavelengths were performed to probe these dynamical influences. The vibrational dynamics associated with S0 were independent of incident wavelength, and this supports the picture that the S1 dynamics are fast relative to the rate of intersystem crossing. The phenyl breathing mode ν19 (860 cm−1) and the symmetric NO2 stretch ν29 (1310 cm−1) exhibited vibrational lifetimes in S0 of 8.1 and 5.2 ps, respectively. No evidence for inhomogeneous broadening of the charge‐transfer band in the UV/Vis absorption spectrum was found.
Barbituric Acid Sensor Based on Molecularly Imprinted Polymer‐ Modified Hanging Mercury Drop Electrode
Authors: Prasad Bhim Bali , Lakshmi Dhana 
Published: May 2005

AbstractA barbituric acid sensor based on molecularly imprinted polymer‐modified hanging mercury drop electrode is reported for sensitive and selective analysis in aqueous and blood plasma samples. It was developed by coating directly the barbituric acid‐ imprinted polymer, which is prepared from melamine and chloranil, onto the surface of a hanging mercury drop electrode under charge‐transfer interaction at +0.3 V (vs. Ag/AgCl) in Model 303A electrode system connected with a polarographic analyzer/stripping voltammeter (PAR Model 264A). The binding event of barbituric acid was detected in the imprinted polymer layer through differential pulse, cathodic stripping voltammetric (DPCSV) signal at optimized operational conditions [accumulation potential +0.3 V (vs. Ag/AgCl), accumulation time 120 s, pH 7.0 (without supporting electrolyte), scan rate 10 mV s−1, pulse amplitude 25 mV]. The limit of detection for barbituric acid was found to be 0.54 ppm (RSD=3.7%, S/N=3). The detection was feasible without any problem of matrix effect or cross reactivity in the linearity range of concentration varying from 0.50 to 125.00 ppm of barbituric acid.
Use of the Comet test and micronucleus assay on human white blood cells for in vitro assessment of genotoxicity induced by different drinking water disinfection protocols
Authors: Maffei Francesca , Buschini Annamaria , Rossi Carlo , Poli Paola , Forti Giorgio Cantelli , Hrelia Patrizia 
Published: May 2005

AbstractSurface water disinfection can lead to the formation of mutagenic/carcinogenic by‐products derived from reactions with naturally occurring inorganic compounds. We investigated the feasibility and potential usefulness of an integrated approach to genotoxicity analysis of drinking water. The approach employed the Comet and micronucleus (MN) assays to evaluate the DNA and chromosomal damage produced by water extracts in human blood cells. Surface water samples from Lago Trasimeno (Italy) were collected in different seasons (July 2000, October 2000, February 2001, and June 2001), and samples were disinfected with sodium hypochloride (NaClO), chlorine dioxide (ClO2), or peracetic acid (PAA). Extracts of untreated and treated water were incubated with primary human leukocytes. The Comet assay revealed both strong seasonal variations and differences between samples processed by the three disinfection protocols. The three disinfectants increased the genotoxicity of the water collected in July 2000 and October 2000, with PAA producing the greatest amount of DNA damage. Extracts of raw water collected in February 2001 produced so much DNA damage that the relative genotoxic potentials of the three disinfectants could not be evaluated. No increase in MN frequency was detected in any of the samples. The multi‐endpoint MN assay indicated, however, that our study samples (especially the sample collected in the February 2001) were cytotoxic. We conclude that this integrated approach to genotoxicity assessment may be useful both for the quality control of raw drinking water and to help compare the potential health risks associated with alternative disinfection processes. Environ. Mol. Mutagen., 2005. © 2005 Wiley‐Liss, Inc.
Cellular modelling in fluvial geomorphology
Authors: Nicholas Andrew P. 
Published: May 2005

AbstractThis paper outlines the principles of cellular modelling in fluvial geomorphology and addresses issues of model formulation and validation in the context of numerical modelling more generally. In doing so it seeks to highlight the prospects for using cellular approaches to develop an improved understanding of both rivers and models. Copyright © 2005 John Wiley & Sons, Ltd.
High‐resolution detection and mapping of genomic DNA alterations in neuroblastoma
Authors: Mosse Yael P. , Greshock Joel , Margolin Adam , Naylor Tara , Cole Kristina , Khazi Deepa , Hii George , Winter Cynthia , Shahzad Syed , Asziz Muhammad Usman , Biegel Jaclyn A. , Weber Barbara L. , Maris John M. 
Published: May 2005

AbstractWe used array‐based comparative genomic hybridization (aCGH) to measure genomic copy number alterations (CNAs) in 42 neuroblastoma cell lines with known 1p36.3, 2p24 (MYCN), 11q23, and 17q23 allelic status. All cell lines showed CNAs, with an average of 22.0% of the genome of each sample showing evidence of gain (11.6%) or loss (10.4%). MYCN amplification was detected in 81% of cell lines, but other regions with high‐level genomic amplification were observed only rarely. Gain of 17q material was present in 75% of the samples, and four discrete genomic regions at 17q23.2–17q25.3 were defined. Novel regions of gain were identified, including a 2.6‐Mb subtelomeric region at 5p that includes the telomerase reverse transcriptase gene (TERT), which was found in 45% of the cell lines. Hemizygous deletions were noted at 1p36.23–1p36.32 and 11q23.3–11q25 in 60% and 36%, respectively, of the samples, with other frequent (>25%) regions of deletion localized to 1p32.1, 3p21.31–3p22.1, 5q35.2–5q35.3, 7q31.2, 7q34, 9q22.3–9q24.1, 10q26.11–10q26.12, 16q23.1–16q24.3, 18q21.32–18q23, and 20p11.21–20p11.23. A smallest region of overlap (SRO) for CNAs was mapped across all experiments and in each case was consistent with or refined the published data. A single cell line showed a homozygous deletion at 3p22.3, which was verified, and this location was refined by FISH and PCR. There was outstanding concordance of aCGH with PCR‐based CNA detection methods. Several potential cooperating loci were identified, including deletion of 11q23–25, which was highly associated with both regional gain and loss at multiple chromosomal loci but was inversely correlated with the deletion of 1p36. Taking all of this together indicates that aCGH can accurately measure CNAs in the neuroblastoma genome and facilitate gene discovery efforts by high‐throughput refinement of candidate loci. Supplementary material for this article can be found on the Genes, Chromosomes and Cancer website at http://www.interscience.wiley.com/jpages/1045‐2257/suppmat/index.html. © 2005 Wiley‐Liss, Inc.
Mitochondrial DNA mutations and mitochondrial DNA depletion in gastric cancer
Authors: Wu Chew‐Wun , Yin Pen‐Hui , Hung Wen‐Yi , Li Anna Fen‐Yau , Li Shu‐Hui , Chi Chin‐Wen , Wei Yau‐Huei , Lee Hsin‐Chen 
Published: May 2005

AbstractGastric carcinoma is one of the most common types of cancer in Taiwan. Somatic mitochondrial DNA (mtDNA) alteration in gastric carcinoma and its association with clinicopathologic features remain unclear. When we used polymerase chain reaction (PCR) and direct sequencing, 15 of the 31 (48%) gastric carcinomas displayed somatic mutations in the D‐loop region, a hot spot for mutations in mtDNA of human cancers. Ten (67%) cancers with the somatic mutations in the D‐loop had insertion or deletion mutations in nucleotide position (np) 303–309 in the mononucleotide repeat region. One carcinoma carried tandem duplication and triplication flanked by mononucleotide repeats starting at np 311 and 568, respectively, in the D‐loop. We also detected the common 4,977‐bp deletion in 17 (55%) of the noncancerous tissue samples, but only in three (9%) carcinomas. Moreover, we quantified the mtDNA content using a competitive PCR technique and found that mtDNA depletion occurred in 17 (55%) of the gastric carcinomas. Although no significant association was found between clinicopathologic features and the mtDNA mutations in the D‐loop, mtDNA depletion was observed significantly in the ulcerated, infiltrating (Borrmann's type III) and diffusely thick (Borrmann's type IV) types of gastric carcinomas (P = 0.018). Our results suggest that somatic mtDNA mutations and mtDNA depletion occur in gastric cancer and that mtDNA depletion is involved in carcinogenesis and/or cancer progression of gastric carcinoma. © 2005 Wiley‐Liss, Inc.
Disruption of the hyaluronan‐based extracellular matrix in spinal cord promotes astrocyte proliferation
Authors: Struve Jaime , Maher P. Colby , Li Ya‐qin , Kinney Shawn , Fehlings Michael G. , Kuntz Charles , Sherman Larry S. 
Published: May 2005

AbstractAstrocyte proliferation is tightly controlled during development and in the adult nervous system. In the present study, we find that a high‐molecular‐weight (MW) form of the glycosaminoglycan hyaluronan (HA) is found in rat spinal cord tissue and becomes degraded soon after traumatic spinal cord injury. Newly synthesized HA accumulates in injured spinal cord as gliosis proceeds, such that high‐MW HA becomes overabundant in the extracellular matrix surrounding glial scars after 1 month. Injection of hyaluronidase, which degrades HA, into normal spinal cord tissue results in increased numbers of glial fibrillary acidic protein (GFAP)‐positive cells that also express the nuclear proliferation marker Ki‐67, suggesting that HA degradation promotes astrocyte proliferation. In agreement with this observation, adding high‐ but not low‐MW HA to proliferating astrocytes in vitro inhibits cell growth, while treating confluent, quiescent astrocyte cultures with hyaluronidase induces astrocyte proliferation. Collectively, these data indicate that high‐MW HA maintains astrocytes in a state of quiescence, and that degradation of HA following CNS injury relieves growth inhibition, resulting in increased astrocyte proliferation. © 2005 Wiley‐Liss, Inc.
Nucleoside transporter expression and function in cultured mouse astrocytes
Authors: Peng Liang , Huang Rong , Yu Albert C.H. , Fung King Y. , Rathbone Michel P. , Hertz Leif 
Published: May 2005

AbstractUptake of purine and pyrimidine nucleosides in astrocytes is important for several reasons: (1) uptake of nucleosides contributes to nucleic acid synthesis; (2) astrocytes synthesize AMP, ADP, and ATP from adenosine and GTP from guanosine; and (3) adenosine and guanosine function as neuromodulators, whose effects are partly terminated by cellular uptake. It has previously been shown that adenosine is rapidly accumulated by active uptake in astrocytes (Hertz and Matz, Neurochem Res 14:755–760, 1989), but the ratio between active uptake and metabolism‐driven uptake of adenosine is unknown, as are uptake characteristics for guanosine. The present study therefore aims at providing detailed information of nucleoside transport and transporters in primary cultures of mouse astrocytes. Reverse transcription‐polymerase chain reaction identified the two equilibrative nucleoside transporters, ENT1 and ENT2, together with the concentrative nucleoside transporter CNT2, whereas CNT3 was absent, and CNT1 expression could not be investigated. Uptake studies of tritiated thymidine, formycin B, guanosine, and adenosine (3‐s uptakes at 1–4°C to study diffusional uptake and 1–60‐min uptakes at 37°C to study concentrative uptake) demonstrated a fast diffusional uptake of all four nucleosides, a small, Na+‐independent and probably metabolism‐driven uptake of thymidine (consistent with DNA synthesis), larger metabolism‐driven uptakes of guanosine (consistent with synthesis of DNA, RNA, and GTP) and especially of adenosine (consistent with rapid nucleotide synthesis), and Na+‐dependent uptakes of adenosine (consistent with its concentrative uptake) and guanosine, rendering neuromodulator uptake independent of nucleoside metabolism. Astrocytes are accordingly well suited for both intense nucleoside metabolism and metabolism‐independent uptake to terminate neuromodulator effects of adenosine and guanosine. © 2005 Wiley‐Liss, Inc.
Glial immunoreactivity for metallothionein in the rat brain
Authors: Young John K. , Garvey Justine S. , Huang P. C. 
Published: May 2005

AbstractA series of frozen and vibratome coronal sections of the rat brain were examined by immunocytochemistry for the presence of a cysteine‐rich metal binding protein, metallothionein (MT). Astrocytes throughout the brain and brainstem stained positively for MT; neurons and oligodendroglia were unstained. Ependymal cells and tanycyte processes in the hypothalamus were also immunoreactive, along with a narrow zone of immunopositivity along the margins of the area postrema. Gomori‐positive astrocytes in the hypothalamus, identifiable by toluidine blue staining, metal‐containing cytoplasmic granules, represented a subset of MT‐positive astrocytes that may be involved in reactions to blood‐borne metal compounds that penetrate into circumventricular organs of the brain.
Schwann cells and cells in the oligodendrocyte lineage proliferate in response to a 50,000 dalton membrane‐associated mitogen present in developing brain
Authors: Nordlund Michael , Hong Dingming , Fei Xun , Ratner Nancy 
Published: May 2005

AbstractThe neuronal cell surface is believed to carry a mitogenic signal for peripheral glial cells. We have purified a mitogen from fetal bovine brain membranes that, in common with the PNS neuronal mitogen, stimulates the proliferation of Schwann cells in vitro and binds heparin. The purified mitogen has an apparent molecular weight of 50,000 daltons as estimated by elution of activity from non‐reducing polyacrylamide gels. Since the developing central nervous system is a rich source of mitogen, we tested whether the protein is mitogenic for one or more cell types isolated from the developing brain. Purified mitogen was added to enriched cultures of astrocytes or developing oligodendrocytes, or to microglial cells. The analyses demonstrated that the protein is mitogenic for developing oligodendrocytes but not astrocytes or microglial cells. These results suggest that during development a membrane‐associated mitogen present in the brain might regulate the proliferation of developing oligodendrocytes, and consequently, the population size of oligodendrocytes in the brain.
Agonist‐evoked Ca2+ transients in primary astroglial cultures–modulatory effects of valproic acid
Authors: Nilsson Michael , Hansson Elisabeth , Rounnbäuck Lars 
Published: May 2005

AbstractCytosolic Ca2+ ([Ca2+]i) activity was measured in individual type 1 astroglial cells in primary culture after exposure to glutamate (Glu), quisqualate (QA), γ‐aminobutyric acid (GABA), 5‐hydroxytryptamine (5HT), and noradrenaline (NA) by using the Ca2+ indicator dye fura‐2/AM in a computerized microspectrofluorimetric system. Various patterns of Ca2+ transients were observed, but the most common was biphasic, having an initial sharp peak, rising immediately after stimulation, and then declining to a lower but sustained Ca2+ level. The only substance that diverged from this pattern was GABA, which induced a Ca2+ response with longer latency and a single‐phase curve. The effects of the anticonvulsive drug Na+‐valproate (VPA) were also investigated. After both acute and chronic (5–7 days) exposure to 10−4 M VPA, the GABA‐evoked rises in [Ca2+]i were completely inhibited. VPA also had acute effects on the 5HT‐ and Glu‐evoked Ca2+ spikes. The Ca2+ responses after 5HT stimulation were greatly reduced after exposure to 10‐4 M VPA. The responses after glutamate stimulation were, on the contrary, increased after a similar exposure. No VPA effects were seen on the curve patterns of QA and NA stimulations. The most frequent agonist‐evoked responses were seen after stimulation with 5HT and NA, where over 80% of the tested cells responded. For QA and Glu, the response frequencies were about 40% each, while for GABA it was 20%. The responses after 5HT and NA stimulation were blocked to baseline levels after exposure to ketanserin (5HT2 receptor antagonist) and a combination of prazosin, yohimbine, and propranolol (α1, α2, and β adrenoceptor antagonists, respectively). The rises in [Ca2+]i after stimulation with QA, Glu, and GABA were partly antagonized by 6‐nitro‐7‐cyano‐quinoxaline‐2,3‐dione (CNQX; a QA receptor antagonist, also tested on the glutamate responses) and bicuculline (GABA receptor antagonists). The biphasic curve forms, after stimulation with Glu, QA, 5HT, and NA, were reduced to single‐phase curves with unaffected or slightly reduced initial peaks when the stimulations were performed in Ca2+‐free medium. Interestingly, in some cells Glu induced a curve form that, different from the other Glu‐evoked responses, consisted of an immediate rise in [Ca2+]i, which persisted at the level of maximal response. Furthermore, this response was completely inhibited in Ca2+‐free buffer. The GABA response was also totally inhibited in Ca2+ ‐free buffer.The results suggest that astrocytes in primary culture respond differently to various receptor agonists, with regard to both the intracellular Ca2+ spiking behavior and the response frequency. Furthermore, the data also show that certain agonist‐evoked rises in [Ca2+]i can be significantly modulated by the neuroactive agent VPA.
Immunomagnetic removal of neurons from developing chick optic tectum results in glial phenotypic instability
Authors: Galileo Deni S. , Linser Paul J. 
Published: May 2005

AbstractThe ability of embryonic day 12 and 13 optic tectum cells to replace depleted A2B5(+) cells and neurons was tested by immunomagnetic cell separation. Nearly all purified surface A2B5(−) cells were identified as glia by immunoreactivity for either glutamine synthetase of galactocerebroside. Most (∼80%) of the purified A2B5(−) cells became A2B5(+) after 1 day in culture, although no increase in the percentage of A2B5(+) cells (from 45%) was observed in control cultures of unpurified cells. Long‐term monolayer cultures from purified cells contained A2B5(+) cells with mostly flattened glial‐like or round process‐free morphology, whereas those from unpurified cells contained many A2B5(+) neurons. The non‐neuronal A2B5(+) cells frequently reacted with antibodies against glial fibrillary acidic protein and another marker expressed by embryonic brain glia, 5A11. Additionally, some flattened glia‐like cells exhibited elaborate networks of anti‐neurofilament‐M‐reactive filaments. We believe these unusual pheno‐types, which appeared only in cultures of purified A2B5(−) cells, arose in response to the immunomagnetic removal of neurons. In conjunction with previous findings, we conclude that the abnormal phenotypes in purified cell cultures represent glia that were unsuccessful in attempting to replenish the depleted neuronal population. This may reflect restricted developmental potentials that arise during brain ontogeny.
Voltage‐gated currents expressed by rat microglia in culture
Authors: Korotzer Andrew R. , Cotman Carl W. 
Published: May 2005

AbstractUsing the whole‐cell patch‐clamp technique, at least three types of voltage‐gated currents expressed by cultured rat microglia were identified: an inward rectifier K+ current, a delayed rectifier K+ current (IK), and a Na+ current activated by depolarization. The inward rectifier conductance was activated by hyperpolarization to potentials more negative than −80 mV, depended on the external K+ concentration, and declined over time during whole cell recording, as the cell was internally dialyzed. The delayed rectifier current was activated by depolarization to potentials more positive than −40 mV and the rates of activation and deactivation showed a voltage‐dependence similar to such currents seen in other preparations. An inward current possibly carried by Na+ was seen in a small percentage of cells. Recordings had been made from two morphological cell types, namely process‐bearing (“ramified”) and non‐process‐bearing (“ameboid”). Each of these currents was present in microglia of both morphological types. However, microglial morphology, which is thought to represent different states of activation, was significantly related to the types of combinations of currents expressed in a given cell. © 1992 Wiley‐Liss, Inc.