bluuebunny/crossref_metadata_2025_split huggingface dataset:
Regeneration in planarians and other worms: New findings, new tools, and new perspectives
Authors: Saló Emili , Baguñà Jaume 
Published: August 2002

AbstractMolecular biology, recombinant DNA techniques, and new methods of cell lineage have reignited the interest of planarians and other worms (mainly annelids and nemerteans) as invertebrate model systems of regeneration. Here, the mean results produced in the last five years are reviewed, an update of the genes and molecules involved in planarian regeneration is provided, and a new morphallactic‐epimorphic model of pattern formation is suggested. Moreover, and most importantly, we highlight the new strides brought upon by genomic/proteomic analyses, RNA interference (RNAi) to inactivate gene function, and Bromodeoxyuridine (BrdU) cell labelling. The raising hope to obtain transformed neoblasts and transgenic planarians is also stressed. Altogether, such approaches will eventually lead to solve the long‐standing open questions on regeneration which still baffles us. Finally, we warn against overlooking the evident links between regeneration processes and those controlling the daily wear and tear of tissues and cells. Both processes act, at least in planarians, upon a unique stem‐cell endowed with an unrivaled developmental potential in the animal kingdom—the neoblast. This cell could be considered the forebear and a model system for stem‐cell analysis. J. Exp. Zool. 292:528–539, 2002. © 2002 Wiley‐Liss, Inc.
The use of low‐molecular‐weight PEIs as gene carriers in the monkey fibroblastoma and rabbit smooth muscle cell cultures
Authors: Lampela Pasi , Räisänen Johanna , Männistö Pekka T. , Ylä‐Herttuala Seppo , Raasmaja Atso 
Published: August 2002

AbstractBackgroundPolyethylenimines (PEIs) and cationic polymers have been used successfully in gene delivery. In earlier reports, only large PEIs (MW>10 000) have shown significant transfection efficiency. In the present study, the roles of small PEIs (MW 700 and 2000) were studied as additional compounds to see if they can improve gene delivery with cationic liposomes.MethodsThe TKBPVlacZ expression plasmid was transfected in the CV1‐P (monkey fibroblastoma) and SMC (rabbit smooth muscle) cell lines using various combinations of PEIs (MW 700, 2000, and 25 000) and Dosper liposomes. The transfection efficiency was determined with the fluorometric ONPG (o‐nitrophenol‐β‐D‐galactopyranoside) assay and histochemical X‐gal staining. The toxicity of the transfection reagents was estimated by the MTT [3‐(4,5‐dimethylthiazolyl‐2)‐2,5‐diphenyl tetrazolium bromide] assay.ResultsTransfection of TKBPVlacZ plasmid by the small PEIs (MW 700 and 2000) combined with Dosper liposomes was associated with high expression of the lacZ reporter gene in the CV1‐P and SMC cell lines. The transfection efficiencies of the low‐molecular‐weight PEI/liposome combinations were several fold higher than those of PEIs or liposomes alone. PEI/liposome combinations had no toxicity on the cell lines tested.ConclusionsThe low‐molecular‐weight PEIs could be used successfully for gene delivery when combined with the cationic liposomes, resulting in a synergistic increase of the transfection efficiency in both cell lines studied. Copyright © 2002 John Wiley & Sons, Ltd.
Total choosability of multicircuits I
Authors: Kostochka Alexandr V. , Woodall Douglas R. 
Published: August 2002

AbstractA multicircuit is a multigraph whose underlying simple graph is a circuit (a connected 2‐regular graph). In this pair of papers, it is proved that every multicircuit C has total choosability (i.e., list total chromatic number) ch′′(C) equal to its ordinary total chromatic number χ′′(C). In the present paper, the kernel method is used to prove this for every multicircuit that has at least two vertices with degree less than its maximum degree Δ. The result is also proved for every multicircuit C for which χ′′(C)≥Δ+2. © 2002 Wiley Periodicals, Inc. J Graph Theory 40: 26–43, 2002
The improved biological properties in mice of 99mTc–TBI for myocardial perfusion imaging
Authors: Zhang X. Zh. , Wang X. B. , Tang Z. G. 
Published: August 2002

AbstractThe aim of this study was to improve the biological properties of 99mTc–TBI complex for myocardial perfusion imaging. The effect of Tween‐80 on the biodistribution in mice of 99mTc–TBI was reported. The experimental results show that liver and blood uptakes of Tween‐80 added (TA) complex are significantly lower than those of corresponding non‐Tween‐80 added (NTA) complex. Also, the clearance rate from blood of TA complex is faster than that of NTA complex. At 60 min post‐injection time, the ratios of heart‐to‐liver, heart‐to‐lung and heart‐to‐blood were 1.29, 137.75 and 4.73, respectively, for the TA complex; however, the corresponding ratios were 0.57, 13.07 and 2.65, respectively, for NTA complex. The biodistribution in mice of the Tween‐80 added 99mTc–TBI (99mTc–TBI(T)) is comparable with the widely used myocardial perfusion imaging agent 99mTc–MIBI in some aspects; especially, the heart‐to‐liver ratios of 99mTc–TBI(T) at various post‐injection times are better than those of 99mTc–MIBI. The biological properties of 99mTc–TBI complex for myocardial imaging were improved significantly by using Tween‐80 as an auxiliary agent. It is worthy of further studies. Copyright © 2001 John Wiley & Sons, Ltd.
Safety aspects and quality assessment in MRI and MRS: A challenge for health care systems in Europe
Authors: de Certaines Jacques D. , Cathelineau Guy 
Published: August 2002

AbstractDespite advances in international cooperation, the application of the safety regulations of different countries remains an important challenge for manufacturers and health care workers in the European Union. Rapid technological development during the last 20 years, and the still controversial nature of certain potential effects of magnetic or electromagnetic fields, make the task particularly difficult for MRI and MRS. As the relevant literature is rather extensive, the present work will limit its goals to four questions: 1) How is MRI and MRS safety regulation managed within the European Union? 2) Concerning direct potential physiological effects, what is presently well known and controlled, and, conversely, what are the remaining open (and often controversial) questions? 3) As metallic implants are probably the main risk in routine MRI, what regulatory strategy is in progress in Europe? 4) As indirect risks related to artifacts must not be underestimated, what European programs have been developed for quality assessment in MRI and MRS? In all of these fields, evidence is provided demonstrating the need for a mutual recognition of common standards for the European Union and the United States. J. Magn. Reson. Imaging 2001;13:632–638. © 2001 Wiley‐Liss, Inc.
Gas‐phase conversion of tetrazoles to oxadiazoles: isolation and characterization of the N‐acylated intermediate
Authors: Seldes A. M. , D'Accorso N. , Souto M. F. , Martins Alho M. , Arabehety C. G. 
Published: August 2002

AbstractThe 5‐substituted tetrazole ring was reacted in the gas phase with an acyl ion generated as the secondary reactive chemical ionization plasma in the mass spectrometer. The product ions obtained, among others, were proposed as the rearranged 2,5‐disubstituted‐1,3,4‐oxadiazole nucleus. Its structure was demonstrated by comparison of the product ion spectrum of the 2,5‐disubstituted‐1,3,4‐oxadiazole derivative obtained by condensed‐phase reaction and the product ion spectrum of the oxadiazole derivative generated in situ by reaction of the 5‐substituted tetrazole derivative with the acyl plasma. It was proposed that the mechanism of this transformation involved the presence of an acylated tetrazole intermediary, which could not be isolated in the condensed phase, followed by the rearrangement, with nitrogen loss, to afford the oxadiazole derivative. Under our conditions we were able to isolate the intermediate ion in the first field free region and demonstrate its structure by collision induced dissociation–tandem mass spectrometry. Copyright © 2001 John Wiley & Sons, Ltd.
Measles virus strains circulating in Ethiopia in 1998–1999: Molecular characterisation using oral fluid samples and identification of a new genotype
Authors: Nigatu W. , Jin L. , Cohen B.J. , Nokes D.J. , Etana M. , Cutts F.T. , Brown D.W.G. 
Published: August 2002

AbstractA measles outbreak in December 1998 in Bedelle (vaccine coverage <40%) and two sporadic cases in Addis Ababa, Ethiopia, were investigated. Paired serum and oral fluid samples were collected 2–8 days after the onset of symptoms. A total of 53 of 55 outbreak cases and both sporadic cases were positive for serum measles virus‐specific IgM. Oral fluid measles‐specific IgM was positive in 71% of cases collected up to 5 days after onset and in 90% collected at 6–8 days. By contrast, 100% of oral fluid samples were positive for measles virus RNA by RT‐PCR, suggesting that early collection of samples favoured the detection of measles virus RNA by RT‐PCR. The measles virus strain in the outbreak was identified as genotype D4. One strain from a sporadic case was also genotype D4; the strain from the other sporadic case was assigned to clade D but was distinct. The degree of divergence from recognised clade D strains suggested that, together with three strains from the United Kingdom, it represents an additional genotype of clade D (GenBank accession numbers AF280800–280807). J. Med. Virol. 65:373–380, 2001. © 2001 Wiley‐Liss, Inc.
Glutamate activates PP125FAK through AMPA/kainate receptors in Bergmann glia
Authors: Millán Alejandro , Aguilar Pablo , Méndez J. Alfredo , Arias‐Montaño José‐Antonio , Ortega Arturo 
Published: August 2002

AbstractGlial glutamate receptors are likely to play a role in plasticity, learning, and memory and in a number of neuropathologies. An enhanced glutamate‐dependent tyrosine phosphorylation has been detected in such processes. Using primary cultures of chick Bergmann glia cells and chick cerebellar slices, we addressed whether glial glutamate receptors can activate the nonreceptor tyrosine kinase pp125 focal adhesion kinase (pp125FAK). A dose‐ and time‐dependent tyrosine phosphorylation of pp125FAK was found in both preparations upon glutamate treatment. This effect was mediated through α‐amino‐3‐hydroxy‐5‐methyl‐4‐isoaxazolepropionate (AMPA)/kainate (KA) receptors, as shown by its inhibition by the specific antagonists 2,3‐dioxo‐6‐nitro‐1,2,3,4‐tetrahydrobenzo[f]quinoxaline‐7‐ sulfonamide (NBQX) and 6,7‐dinitroquinoxaline‐2,3‐dione (DNQX) and the lack of effect of metabotropic agonists. FAK tyrosine phosphorylation was dependent on phosphatidylinositol 3‐kinase activity. As expected, an increase in pp125FAK catalytic activity was found upon glutamate treatment. Immunprecipitation experiments demonstrated that FAK associates with ionotropic glutamate receptors. Taken together, these results suggest a role for glial glutamate receptors in cytoskeletal rearrengments and focal adhesion contact formation and provide new insight into the signaling transactions elicited by this neurotransmitter in glial cells. J. Neurosci. Res. 66:723–729, 2001. © 2001 Wiley‐Liss, Inc.
Glutamate signalling and secretory phospholipase A2 modulate the release of arachidonic acid from neuronal membranes
Authors: Rodriguez de Turco Elena B. , Jackson Fannie R. , DeCoster Mark A. , Kolko Miriam , Bazan Nicolas G. 
Published: August 2002

AbstractThe lipid mediators generated by phospholipases A2 (PLA2), free arachidonic acid (AA), eicosanoids, and platelet‐activating factor, modulate neuronal activity; when overproduced, some of them become potent neurotoxins. We have shown, using primary cortical neuron cultures, that glutamate and secretory PLA2 (sPLA2) from bee venom (bv sPLA2) and Taipan snake venom (OS2) elicit synergy in inducing neuronal cell death. Low concentrations of sPLA2 are selective ligands of cell‐surface sPLA2 receptors. We investigated which neuronal arachidonoyl phospholipids are targeted by glutamate‐activated cytosolic calcium‐dependent PLA2 (cPLA2) and by sPLA2. Treatment of 3H‐AA‐labeled cortical neurons with mildly toxic concentrations of sPLA2 (25 ng/ml, 1.78 nM) for 45 min resulted in a two‐ to threefold higher loss of 3H‐AA from phosphatidylcholine (PC) than from phosphatidylethanolamine (PE) and in minor changes in other phospholipids. A similar profile, although of greater magnitude, was observed 20 hr posttreatment. Glutamate (80 μM) induced much less mobilization of 3H‐AA than did sPLA2 and resulted in a threefold greater degradation of 3H‐AA PE than of 3H‐AA PC by 20 hr posttreatment. Combining sPLA2 and glutamate resulted in a greater degradation of PC and PE, and the N‐methyl‐D‐aspartate receptor antagonist MK‐801 only blocked glutamate effects. Thus, activation of the arachidonate cascade induced by glutamate and sPLA2 under experimental conditions that lead to neuronal cell death involves the hydrolysis of different (perhaps partially overlapping) cellular phospholipid pools. © 2002 Wiley‐Liss, Inc.
Response of amoeboid microglia/brain macrophages in fetal rat brain exposed to a teratogen
Authors: Hao Ai‐Jun , Dheen S. Thameem , Ling Eng‐Ang 
Published: August 2002

AbstractThis study examined the time course response of amoeboid microglia/brain macrophages in the rat fetus induced by a single intraperitoneal injection of cyclophosphamide, a teratogen, into the mother rat at 13 days of gestation. Compared to the normal fetal brain, a marked increase in amoeboid microglia was observed in the telencephalon and diencephalon of experimental fetuses, especially in those killed at embryonic day 15. Conglomerations of microglia occurred in the dorsal and superior neuroepithelium of diencephalon, basal telencephalon, cortical neuroepithelium, and hippocampal formation as identified with OX‐42, OX‐18, and ED‐1 by immunohistochemistry. Rhodamine isothiocynate (RhIc) as a tracer was injected via the tail vein into the pregnant rat to assess the phagocytic capability of these cells. Following the tracer injection, none of microglial cells in normal fetal brain was detectable. RhIc, however, was readily taken up by amoeboid microglia in fetal brain with injury insult. Double labeling has shown that the RhIc‐labeled cells were immunoreactive with ED‐1, OX‐42, OX‐18, and OX‐6, confirming their microglial nature. Microglial proliferation was assessed by immunohistochemistry using bromodeoxyuridine, which showed a marked increase in mitotic activity. Confocal microscopic analysis revealed that a varying number of microglia coexpressed iNOS, macrophage colony‐stimulating factor (M‐CSF), and ICAM‐1. RT‐PCR analysis showed increased expression of M‐CSF mRNA. Furthermore, colony‐stimulating factor‐1 receptor mRNA was localized in microglia by in situ hybridization. The present results suggest that NO along with M‐CSF and ICAM‐1 is involved in microglial proliferation in prenatal brain injury. J. Neurosci. Res. 64:79–93, 2001. © 2001 Wiley‐Liss, Inc.
Tenascin‐Y is concentrated in adult nerve roots and has barrier properties in vitro
Authors: Tucker Richard P. , Hagios Carmen , Santiago Alicia , Chiquet‐Ehrismann Ruth 
Published: August 2002

AbstractSeveral molecules have been identified as potential sources of the barriers to glial cell mixing and sensory regeneration that exist at the boundary between the peripheral and central nervous systems, including tenascin‐C, tenascin‐R, chondroitin sulfate proteoglycans, and NG2. Here we show that tenascin‐Y, the avian homologue of tenascin‐X, is concentrated in the proximal portions of peripheral nerves in the chicken. In vitro analyses of cultures enriched for Schwann cells demonstrate that recombinant tenascin‐Y has dose‐dependent effects on glial cell attachment, spreading, and migration. In addition, nanomolar concentrations of tenascin‐Y cause the rapid collapse of sensory growth cones cultured on fibronectin, and regenerating sensory neurites preferentially migrate on fibronectin and avoid tenascin‐Y in microstripe assays. We conclude that the expression pattern of tenascin‐Y and its properties in vitro are consistent with a role as an inhibitor of glial cell migration and sensory regeneration in nerve roots. J. Neurosci. Res. 66:439–447, 2001. © 2001 Wiley‐Liss, Inc.
Early formation of mature amyloid‐β protein deposits in a mutant APP transgenic model depends on levels of Aβ1–42
Authors: Rockenstein Edward , Mallory Margaret , Mante Michael , Sisk Abyanné , Masliaha Eliezer 
Published: August 2002

AbstractThe main objective of the present study was to develop an alternative singly‐transgenic (tg) hAPP model where amyloid deposition will occur at an earlier age. For this purpose, we generated lines of tg mice expressing hAPP751 cDNA containing the London (V717I) and Swedish (K670M/N671L) mutations under the regulatory control of the murine (m)Thy‐1 gene (mThy1‐hAPP751). In the brains of the highest (line 41) and intermediate (lines 16 and 11) expressers, high levels of hAPP expression were found in neurons in layers 4–5 of the neocortex, hippocampal CA1 and olfactory bulb. As early as 3–4 months of age, line 41 mice developed mature plaques in the frontal cortex, whereas at 5–7 months plaque formation extended to the hippocampus, thalamus and olfactory region. Ultrastructural and double‐immunolabeling analysis confirmed that most plaques were mature and contained dystrophic neurites immunoreactive with antibodies against APP, synaptophysin, neurofilament and tau. In addition, a decrease in the number of synaptophysin‐immunoreactive terminals was most prominent in the frontal cortex of mice from line 41. Mice from line 11 developed diffuse amyloid deposits at 11 months of age, whereas mice from line 16 did not show evidence of amyloid deposition. Analysis of Aβ by ELISA showed that levels of Aβ1–40 were higher in mice that did not show any amyloid deposits (line 16), whereas Aβ1–42 was the predominant species in tg animals from the lines showing plaque formation (lines 41 and 11). Taken together this study indicates that early onset plaque formation depends on levels of Aβ1–42. J. Neurosci. Res. 66:573–582, 2001. © 2001 Wiley‐Liss, Inc.
A statistical–topographic model using an omnidirectional parameterization of the relief for mapping orographic rainfall
Authors: Drogue G. , Humbert J. , Deraisme J. , Mahr N. , Freslon N. 
Published: August 2002

AbstractThe knowledge of rainfall patterns is a key issue for regionalization in hydroclimatic studies. In mountainous areas, the sparsity of the measurement network and the complexity of relationships between rainfall and topography make an accurate and reliable spatialization of rainfall amounts at the regional scale difficult. The purpose of this paper is to present an objective, analytical and automatic model of quantification and mapping of orographic rainfall applied to the north‐eastern part of France but also applicable in other complex terrain. PLUVIA distributes point measurements of monthly, annual and climatological rainfall to regularly spaced grid cells through a multiple regression analysis of rainfall versus morpho‐topographic parameters derived from a digital elevation model. The use of an omnidirectional parameterization of the topography induced by a windowing technique allows better account to be taken of the synoptic‐scale weather systems generating the different rainfall quantities of interest and the spatial scale of orographic effects. It also provides a more physical interpretation of geographical and topographical parameters selected for spatial estimation. The application relies on a network of more than 150 rain gauges spread over 30 000 km2 and concerns monthly to several yearly amounts of a sequence of 20 years. Advantages and limitations of the PLUVIA system are compared with those of two commonly used methods of multi‐variate geostatistics: kriging with external drift and extended collocated co‐kriging. Copyright © 2002 Royal Meteorological Society.
The anharmonic behavior of the oxygen modes in YBa2Cu3Ox compounds
Authors: Liarokapis E. , Palles D. , Conder K. , Kaldis E. 
Published: August 2002

AbstractThe anharmonic behavior of the Raman‐active oxygen modes was examined in YBa2Cu316,18Ox compounds over the whole range of oxygen doping (6 < x < 7). The apex phonon of Ag symmetry shows a small anharmonicity in the range of 6.4 < x < 6.9, which can be attributed to the anharmonic behavior of this mode in one of the constituent phases (ortho‐II, ortho‐III, etc.), but not in the ortho‐I phase. The B1g mode does not show any anharmonicity over the whole range of oxygen doping, but characteristic spectral changes appear for x ≈ 6.3 and 6.7. At the lowest oxygen content studied (x = 6.03), there is a considerable amount of anharmonicity for the in‐phase phonon of the plane oxygen atoms, which remains large until x ≈ 6.3, at the phase transition to the tetragonal phase, where it drops to zero. It increases again for x ≈ 6.4 and then gradually decreases with doping to disappear at the optimal doping. If these changes are combined with the spectral modifications of the B1g and in‐phase modes, they indicate that local structural changes are induced by the transfer of carriers to the CuO2 planes at x ≈ 6.3, which are related to the reduction in anharmonicity, the pinning of the carriers and superconductivity. Copyright © 2001 John Wiley & Sons, Ltd.
Vibrational analysis of NADH cofactors bound to glycerol‐3‐phosphate dehydrogenase and dogfish lactate dehydrogenase
Authors: van Beek Jeroen , Deng Hua , Callender Robert , Burgner John 
Published: August 2002

AbstractThe dehydrogenases catalyze the interconversions of aldehydes and alcohols in hydride transfer reactions to and from the re or si face of the nicotinamide ring of NAD with a high degree of stereospecificity. We report on the Raman spectra of NADH bound to dogfish lactate dehydrogenase (dfLDH), which transfers to and from the re face, and glycerol‐3‐phosphate dehydrogenase (G3PDH), which transfers to and from the si face. All theories of the mechanism of the stereospecificity must be in accord with the ground‐state native protein–cofactor structure, and the vibrational spectrum of the dihydronicotinamide ring of NADH is sensitive to apoprotein–cofactor interactions. Our results show that the amide NH2 rocking mode shifts up by about 30 cm−1 when NADH is bound in dfLDH while virtually unchanged in G3PDH. The upward shift of the rocking mode indicates a stronger hydrogen bonding on the NH2 moiety in dfLDH. Thus, the results are interpreted to show that the bound dihydronicotinamde head group interacts more strongly with surrounding protein and deforms to a greater extent in dfLDH than in G3PDH. It is concluded that a simple geometrical interpretation explaining the stereospecificity of hydride transfer in dehydrogenases is an adequate molecular description and that there is no need to invoke ‘activation’ of hydride transfer from one side of the NADH ring over the other. On the other hand, the results suggest that the fidelity of the stereospecificity for G3PDH should be much less than that found for LDH. Copyright © 2002 John Wiley & Sons, Ltd.