bluuebunny/crossref_metadata_2025_split huggingface dataset:
Differential distribution of PDE4D splice variant mRNAs in rat brain suggests association with specific pathways and presynaptical localization
Authors: Miró Xavier , Pérez‐Torres Silvia , Puigdomènech Pere , Palacios José M. , Mengod Guadalupe 
Published: October 2002

AbstractcAMP plays an important role as a second‐messenger molecule controlling multiple cellular processes. Its hydrolysis provides an important mechanism by which cAMP levels are regulated. This is performed by a large multigene family of cyclic nucleotide phosphodiesterases (PDEs). Members of the PDE4 enzyme family are selectively inhibited by rolipram. Five different mRNA splice forms for PDE4D have been isolated. Here, we analyzed the regional distribution of the mRNAs coding for the splice variants PDE4D1, PDE4D2, PDE4D3, PDE4D4, and PDE4D5 in the rat brain by in situ hybridization histochemistry using specific radiolabeled oligonucleotides. We found that all five splice variants showed a distinct distribution pattern and, in some cases, in association with specific brain pathways. The most relevant differences were in hippocampal formation, medial habenula, basal ganglia, and area postrema, at both the regional and cellular level. The dorsal and median raphe nuclei exclusively contained PDE4D2 mRNA transcripts, probably located on serotonergic cells. PDE4D1 mRNA was expressed in some white matter cells. PDE4D1 and PDE4D2 mRNA splice forms presented a similar distribution in the area postrema, whereas for PDE4D4 and PDE4D5 the cellular distribution presented a complementary pattern. The differential expression of PDE4D mRNA splice variants in the area postrema is consistent with their possible involvement in emesis control and suggests new molecular targets for a more selective drug design. Synapse 45:259–269, 2002. © 2002 Wiley‐Liss, Inc.
Fear‐like biochemical and behavioral responses in rats to the predator odor, TMT, are dependent on the exposure environment
Authors: Morrow Bret A. , Elsworth John D. , Roth Robert H. 
Published: October 2002

AbstractSeveral laboratories have reported that exposure to predator odor can result in stress‐like effects in rodents. While some laboratories have reported fear‐like alterations in behavior, other laboratories, including our own, have failed to consistently observe fearful behaviors in rats exposed to the predator odor TMT. One potential contributing factor to this discrepancy is the handling of the rat and its test environment. In the current report, we examine biochemical, endocrinological, and behavioral effects of TMT in two distinct open fields: one small, familiar, and dimly lit, while the other was large, novel, and brightly lit. Only exposure to TMT in the large, novel open field resulted in fearful behavior; however, no increase in dopamine turnover was noted compared to no odor and control odor rats. As expected, the different open fields resulted in some biochemical and behavioral differences, including more horizontal locomotion and less grooming, higher serum corticosterone, and increased dopamine turnover in the ventral prefrontal cortex in the large open field. Finally, compared to the same open field controls, TMT exposure elevated rat serum corticosterone levels in both open fields and dopamine turnover in the dorsal and ventral medial prefrontal cortex and amygdala of rats only in the small, familiar open field. These results indicate that the TMT‐induced biochemical activation of may occur without detectable fearful behaviors and may indicate a mechanism that prepares the animal for the expression of a fearful response if additional provocative stimuli are present. Synapse 46:11–18, 2002. © 2002 Wiley‐Liss, Inc.
High‐Throughput Approaches for the Discovery and Optimization of New Olefin Polymerization Catalysts
Authors: Murphy Vince , Bei Xiaohong , Boussie Thomas R. , Brümmer Oliver , Diamond Gary M. , Goh Christopher , Hall Keith A. , Lapointe Anne M. , Leclerc Margarete , Longmire James M. , Shoemaker James A.W. , Turner Howard , Weinberg W. Henry 
Published: October 2002

AbstractThe discovery of new olefin polymerization catalysts is currently a time‐intensive trial‐and‐error process with no guarantee of success. A fully integrated high‐throughput screening workflow for the discovery of new catalysts for polyolefin production has been implemented at Symyx Technologies. The workflow includes the design of the metal–ligand libraries using custom–made computer software, automated delivery of metal precursors and ligands into the reactors using a liquid‐handling robot, and a rapid primary screen that serves to assess the potential of each metalligand‐activator combination as an olefin polymerization catalyst. “Hits” from the primary screen are subjected to secondary screens using a 48‐cell parallel polymerization reactor. Individual polymerization reactions are monitored in real time under conditions that provide meaningful information about the performance capabilities of each catalyst. Rapid polymer characterization techniques support the primary and secondary screens. We have discovered many new and interesting catalyst classes using this technology. © 2002 The Japan Chemical Journal Forum and Wiley Periodicals, Inc., Chem Rec 2: 278–289; 2002: Published online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/tcr.10025
Molecular Sieving and Sensing with Gold Nanotube Membranes
Authors: Wirtz Marc , Parker Matthew , Kobayashi Yoshio , Martin Charles R. 
Published: October 2002

AbstractWe have developed a new class of synthetic membranes that consist of a porous polymeric support that contains an ensemble of gold nanotubes that span the thickness of the support membrane. The support is a commercially available microporous polycarbonate filter with cylindrical nanoscopic pores. The gold nanotubes are prepared via electroless deposition of Au onto the pore walls; i.e., the pores act as templates for the nanotubes. We have shown that by controlling the Au deposition time, Au nanotubes that have effective inside diameters of molecular dimensions (<1 nm) can be prepared. These nanotube membranes can be used to cleanly separate small molecules on the basis of molecular size. Furthermore, use of these membranes as a novel electrochemical sensor is also discussed. This new sensing scheme involves applying a constant potential across the Au nanotube membrane and measuring the drop in the transmembrane current upon the addition of the analyte. This paper reviews our recent progress on size‐based transport selectivity and sensor applications in this new class of membranes. © 2002 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Chem Rec 2:259–267, 2002: Published online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/tcr.10027
Immunocompetence of bivalve hemocytes as evaluated by a miniaturized phagocytosis assay
Authors: Blaise C. , Trottier S. , Gagné F. , Lallement C. , Hansen P.‐D. 
Published: October 2002

AbstractImmune function in bivalves can be adversely affected by long‐term exposure to environmental contaminants. Investigating alterations in immunity can therefore yield relevant information about the relationship between exposure to environmental contaminants and susceptibility to infectious diseases. We have developed a rapid, cost‐effective, and miniaturized immunocompetence assay to evaluate the phagocytic activity, viability, and concentration of hemocytes in freshwater and marine bivalves. Preliminary experiments were performed to optimize various aspects of the assay including 1) the time required for adherence of hemocytes to polystyrene microplate wells, 2) the time required for internalization of fluorescent bacteria, 3) the ratio of hemocytes to fluorescent bacteria in relation to phagocytosis, 4) hemolymph plasma requirements, and 5) the elimination of fluorescence from (noninternalized) bacteria adhering to the external surface of hemocytes. The results of these experiments showed the optimal adherence time for hemocytes in microplate wells to be 1 h, that phagocytosis required at least 2 h of contact with fluorescently labeled E. coli cells, that the number of fluorescent E. coli cells had a positive effect on phagocytic activity, that at least 2.5 million cells/mL were required to measure a significant intake, and that a linear increase in uptake of bacteria (R = 0.91; p < 0.01) could be obtained with concentrations of up to 1.3 × 106 hemocytes/mL. Afterward, the assay was used in two field studies to identify sites having the potential to affect the immunocompetence of bivalves. The first study was conducted on Mya arenaria clams collected at selected contaminated sites in the Saguenay River (Quebec, Canada), and the second examined Elliptio complanata freshwater bivalves that had been exposed to a municipal effluent plume in the St. Lawrence River (Quebec, Canada). In the Saguenay River field study a significant increase in phagocytosis was observed at sites closest to polluted areas. Phagocytotic activity varied over time and was highest during the warmest months (June, July, and August), closely paralleling the spawning period of Mya arenaria clams. In contrast, a drop in phagocytic activity was observed in Elliptio complanata mussels exposed to surface water 4 km downstream of a major municipal effluent plume, with a concomitant increase in the number of hemocytes in the hemolymph. It appears that both immunosuppressive and immunostimulative effects are likely to occur in the field and that responses will be influenced by the type and intensity of contaminants at play. © 2002 Wiley Periodicals, Inc. Environ Toxicol 17: 160–169, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/tox.10047
A novel nucleolar biomarker in plant and animal cells for assessment of substance cytotoxicity
Authors: Arkhipchuk V. V. , Garanko N. N. 
Published: October 2002

AbstractThe cytotoxicity of three substances (mercuryII, metolachlor, and 4‐nitroquinoline‐N‐oxide) was assessed with a set of nucleolar parameters: the average number of nucleoli, the average volume of a single nucleolus, and the proportion of cells with heteromorphic‐paired nucleoli (PNhet). Their toxic impact was studied on cells of animal and plant test organisms: onion (Allium cepa), lettuce (Lactuca sativa), and hydra (Hydra attenuata). In general, at concentrations near IC/LC50 the three chemicals produced similar cytogenetic effects after 30–360 min of contact. For instance, in plant cells (Allium cepa and Lactuca sativa) the toxicants increased the percentage of cells with PNhet, decreased the volume of single nucleoli, and exerted no significant impact on the nucleolar number. In animal cells (Hydra attenuata), they reduced the size of nucleoli, produced no effect on the number of nucleoli, but decreased the share of cells with PNhet. Also, the chemicals affected the cells of the three test organisms to different degrees. Thus, the effectiveness of our approach of using nucleolar biomarker (use of the proposed set of parameters and time schedule of several determinations in the first hours of toxicant contact, etc.) as a means of assessing cytotoxicity was confirmed. © 2002 Wiley Periodicals, Inc. Environ Toxicol 17: 187–194, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/tox.10056
Multi‐carrier platform for wireless communications. Part 2: OFDM and MC‐CDMA systems with high‐performance, high‐throughput via innovations in spreading
Authors: Nassar Carl R. , Natarajan Bala , Wiegandt David , Wu Zhiqiang 
Published: October 2002

AbstractMulti‐carrier technologies in general, and OFDM and MC‐CDMA in particular, are an integral part of the wireless landscape. In this second part of a two‐part survey, the authors present an innovative set of spreading codes known as CI codes, and demonstrate how these significantly increase performance and capacity in OFDM and MC‐CDMA systems, all the while eliminating PAPR concerns. Regarding OFDM: the spreading of each symbol over all N carriers using CI spreading codes (replacing the current one symbol per carrier strategy) are presented. CI codes are ideally suited for spreading OFDM since, when compared to traditional OFDM, CI‐based OFDM systems achieve the performance of coded OFDM (COFDM) while maintaining the throughput of uncoded OFDM, and, at the same time, eliminate PAPR concerns. When applied to MC‐CDMA, CI codes provide a simple means of supporting 2N users on N carriers while maintaining the performance of an N‐user Hadamard Walsh code MC‐CDMA system, i.e., CI codes double MC‐CDMA network capacity without loss in performance. The CI codes used in OFDM and MC‐CDMA systems are directly related to the CI pulse (chip) shapes used to enhance TDMA and DS‐CDMA (see part 1): hence, the CI approach provides a common hardware platform for today's multi‐carrier/multiple‐access technologies, enabling software radio applications. Copyright © 2002 John Wiley & Sons, Ltd.
Measurement of L subshell x‐ray production cross‐sections at energy 31.635 keV and L subshell fluorescence yields for elements 74 ≤ Z ≤ 92
Authors: Ertuǧrul M. , Kaya A. , Doǧan O. , Turgut Ü. , Şimşek Ö. , Söǧüt Ö. , Karagöz D. 
Published: October 2002

AbstractThe Ll, Lα, Lβ and Lγ x‐ray production cross‐sections were measured for seven elements in the atomic range 74 ≤ Z ≤ 92 at 31.635 keV. The values of Li subshell fluorescence yields (ω1, ω2 and ω3) were measured for the same elements using these measured cross‐section values and the theoretical Li subshell photoionization cross‐sections, Coster–Kronig transition probabilities and emission rates. The measured x‐ray production cross‐sections values are in general agreement with the theoretical values evaluated using L subshell fluorescence yields, Coster–Kronig transition probabilities, emission rates and subshell photoionization cross‐sections. Copyright © 2002 John Wiley & Sons, Ltd.
Management and husbandry of duikers at the Los Angeles Zoo
Authors: Barnes Robert , Greene Kelley , Holland Jeff , Lamm Marnie 
Published: October 2002

AbstractThe Los Angeles Zoo has maintained and managed six different species of forest duikers since 1975. Over the years we have achieved relative success with the majority of these species. The maintenance and breeding of duikers has proved to be difficult at best. The major problems that we have experienced concern diet, stress‐related medical conditions, neonatal mortality, and postanesthetic pneumonia. As concentrate selectors, duikers have a diet relatively low in fiber, a well‐developed ability to forage selectively, a rumen bypass that is functionally important, a rapid passage and high fermentation rate for starch, and frequently encountered toxins. From an examination of the captive diet of duikers it is evident that the domestic fruits fed to duikers in captivity are not well suited for them. Duikers are highly susceptible to the slightest amount of stress. The group size in which duikers are managed has proved to be critical in the successful management of these species. In our earlier years of duiker management we often kept five or more animals together in a single exhibit. This would at times result in stress‐related jaw abscesses. Our group size has since been reduced to no more than three animals in any one exhibit. Since 1977, the Los Angeles Zoo has had 92 duiker births. The survival rate past 6 months of age has been 61%. Of the 36 neonatal deaths, 42% were stillborn or died within a few hours of birth. Hypothermia and maternal neglect have been linked to infant mortality. Duikers are also easily prone to capture myopathy and regurgitation during anesthesia or capture, which can often lead to aspiration pneumonia. If at all possible, the capture and restraint of a duiker should be avoided. However, there are times when the capture or restraint (chemically or manually) of a duiker is required. Zoo Biol 21:107–121, 2002. © 2002 Wiley‐Liss, Inc.
Cytochemical analysis of the content of chicken thrombocytes vacuoles.
Authors: Taffarel Marilia , Oliveira Marcia P. 
Published: October 2002

AbstractThe content of the large vacuoles present in chicken thrombocytes was analyzed by the use of cytochemical techniques which indicated the presence of basic proteins, unsaturated fatty acids, sugars rich in viccinal hydroxyl groups, linked to proteins or lipids and acid phosphatase. These substances perform one of the most conspicuous functions of these cells, which is phagocytosis. In addition, thrombocytes are committed to hemostasis. Both functions make these cells similar to human platelets, even though having different origins and morphologic characteristics. The large vacuoles described are connected to the open canalicular system (OCS) and together with other cellular structures they contribute to the endocytic system.
The development of an enzyme‐linked immunosorbent assay for the determination of cortisol binding globulin.
Authors: van Rijswijk A. W. , Morgenthal J. C. , Taljaard J. J. F. 
Published: October 2002

AbstractA simple, reliable and reproducible enzyme‐linked immunosorbent assay (ELISA) using polyclonal antibodies for human cortisol binding globulin (CBG) has been developed. The sensitivity of the ELISA (1.20 fmol CBG/well) compared favourably with the sensitivity of other immunoassays. The excellent agreement (r= 0.98) seen between the present study and a binding assay indicates that the polyclonal antibodies used recognize only intact steroid‐binding CBG. The intra‐ and inter‐assay coefficient of variation (4.0% and 7.1% respectively) compared favourably with those reported by other authors.
Spatio‐temporal regulation of glycolysis and oxidative phosphorylation in vivo in tumor and yeast cells.
Authors: Cortassa Sonia , Aon Miguel A. 
Published: October 2002

ABSTRACTRecent advances in the in vivo control and regulation of glycolysis and oxidative phosphorylation in yeast and tumor cells is revised. New insigths are presented from old and new experimental data interpreted in the light of powerful new technologies (e.g. NMR confocal microscopy) and quantitative techniques combined with mathematical modeling. Those new aspects are mainly concerned with the dynamical organization of glycolysis and oxidative phosphorylation which emerges from the multiple interactions between compartments and processes inside the cells. Those compartments may be of structural origin, e.g. plasma membrane defining the cell boundary, mitochondrial‐cytoplasmic, or functional ones such as the alternative association‐dissociation of enzymes to subcellular structures (e.g. mitochondria, cytoskeleton) with different kinetic properties in each state. A novel regulatory mechanism concerning polymerization‐depolymerization of microtubular protein may add a new dimension to the in vivo physiological properties of cells. One main suggestion coming from the modulatory power of the polymeric status and concentration of cytoskeleton components is that it could function as an intracellular mechanism of synchronization between microscopic (local) to macroscopic (global) processes. How the cell "mixes" or switches on or off those regulatory steps or effectors under different physiological and environmental conditions and for different genetic backgrounds, is a main avenue of systematic research for the future.
Nucleolar organization as revealed in cycloheximide treated cells
Authors: Ghosh Sibdas , Paweletz Neidhard 
Published: October 2002

ABSTRACTThe nucleolar organisation has been studied in cycloheximide treated rat kangaroo cells. Within 1 h of treatment most nucleoli become loose and reveal a nucleolonemal network. With longer treatment the granules are scarce and the nucleolonemal network becomes more prominent. The network reveals units comparable to the rDNA transcriptional units in length. The nucleolonemal units consist of tufts of fibrils. When cycloheximide is withdrawn, granules reappear and obliterate the nucleolonemal network.
Metabolism of N′‐nitrosonornicotine by adult and fetal human oesophagal cultures
Authors: Chakradeo P. P. , Nair J. , Bhide S. V. 
Published: October 2002

AbstractThe metabolism of [3H]labelled N‐Nitrosonornicotine a major constituent of the class of Tobacco Specific Nitrosamines was studied in adult and fetal human oesophageal cultures. The metabolites were separated by HPLC and were identified when compared to the standards as OH‐acid from 5′hydroxylation, NNN‐1‐N‐oxide formed via the pyridine N‐oxidation pathway and Keto acid from 2′hydroxylation in both the adult and fetal cultures. These results indicate that hydroxylation which leads to electrophilic diazohyroxides is the major pathway of NNN metabolism in cultured human oesophagus. In the adult cultures levels of metabolites formed were 20.32 pmoles/μg DNA of OH acid 11.08pmoles/μg DNA of NNN‐1‐N‐oxide and 7.67pmoles/μg DNA of Keto acid. In the fetal cultures levels were 10.85pmoles/μg DNA of OH acid, 9.40pmoles/μg DNA of NNN‐1‐N‐oxide and 7.91pmoles/μg DNA of Keto acid. These results indicate that α‐hydroxylation is the key step in the metabolic activation of NNN in human oesophagus.
A GCN‐like response in Candida albicans.
Authors: Pereira Sarita Anne , Livi George P. 
Published: October 2002

AbstractThe control of amino acid and purine biosynthesis in the yeast Saccharomyces cerevisiae is mediated by the transcriptional activator GCN4. We previously identified the presence of two putative GCN4 responsive elements (GCREs) in the promoter sequence of the Candida albicans ARO3 gene, which encodes an enzyme in the aromatic amino acid pathway. We now show that amino acid deprivation results in a dramatic rise in the steady‐state level of ARO3‐specific mRNA, indicative of a GCN‐like pathway in C. albicans.
Tyrphostin induces non‐apoptotic programmed cell death in colon tumor cells
Authors: Szende B. , Kéri Gy. , Szegedi Zs. , Benedeczky I. , Csikós A. , Örfi L. , Gazit A. 
Published: October 2002

AbstractThe programmed cell death inducing effect of the EGF receptor tyrosine kinase inhibitor α‐cyano‐3,4‐dihydroxycinnamthioamide (AG213) was investigated in vitro on HT‐29 human colon tumor. AG213 at concentrations between 45 to 450 μM blocks the proliferation of HT‐29 cells. Morphological findings suggest that the selective tyrosine kinase inhibitor AG213 induces Clarke III type (non‐lysosomal vesiculate cytoplasmic) programmed cell death; unlike ATP analog non‐selective tyrosine kinase inhibitors like Genistein which were found to induce apoptosis. Cycloheximide and Actinomycin‐D reduced the effect of AG213 pointing to the fact that protein and RNA synthesis are also needed for this form of cell death. Acid phosphatase activity was found in the Golgi and in the newly formed intracytoplasmic vacuoles 3 hours after AG213 treatment which disappeared by 6 hours. The induction of Clarke III cell death by tyrosine kinase inhibitors may open a new modality to selective killing of tumor cells.
The DNA binding affinity of rat liver nucleoproteins to the regulatory elements of the haptoglobin and α2‐macroglobulin genes.
Authors: Petrović Miodrag , Bogojević Desanka , Grigorov Ilijana , Ševaljević Ljiljana 
Published: October 2002

AbstractTranscriptional regulation and binding interactions between soluble nucleoproteins and the hormone response elements (REs) of the rat haptoglobin (Hp) and α2‐macroglobulin (α2MG) genes was examined in the livers of rats during the acute‐phase reaction. Our results demonstrate that the elevation of the Hp and α2MG genes' transcription rates in acute‐phase liver relies essentially on an increase in the binding‐affinity of pre‐xisting soluble nucleoproteins, enhancing their capability to bind the examined cis‐regulatory elements. The 35kD nucleoprotein that displayed an acute‐phase inducible affinity to bind hormone REs of rat Hp and α2MG genes, was identified as a C/EBPβ isoform.