bluuebunny/crossref_metadata_2025_split huggingface dataset:
Olfactory ensheathing cells: Time lapse imaging of cellular interactions, axonal support, rapid morphologic shifts, and mitosis
Authors: Van Den Pol Anthony N. , Santarelli Justin G. 
Published: February 2003

AbstractOlfactory ensheathing cells (OECs) have considerable potential for facilitating axonal growth across regions of spinal cord and brain injury but in this context have been studied primarily in static images of fixed tissue from the olfactory system or after transplantation. In the present work, we studied the behavior of live OECs, and their interactions with neurons, Schwann cells, and astrocytes by using cells that express the reporter gene coding for green fluorescent protein (GFP); the work is based on combinations of fluorescence, phase contrast, digital time lapse imaging, and P75 immunocytochemical identification. Cultures, explants, and regions of olfactory system slices rich in OECs enhanced axonal growth of cerebellar granule cells or hippocampal neurons; axons grew parallel to the long axis of fusiform OECs. Neuron cell bodies and axons preferred OECs over artificial substrates. Axons and neuron cell bodies can take active or passive roles in extension and migration on underlying motile OECs and move from one OEC to another. Axon extension was facilitated to a similar degree by OECs and Schwann cells, whereas astrocytes were more likely to integrate with existing OECs than with Schwann cells. OECs showed a dramatic ability to rapidly change shape, size, and direction of migration and to undergo mitosis. Mitosis was characterized by a quick retraction of all processes, thereby forming a sphere that divided into spherical daughter cells within minutes. Progeny OECs might take on the parental or a non‐parental morphotype, with both daughter cells showing robust expression of GFP. Together these OEC data demonstrated a substantial plasticity and capability for relatively rapid changes in structure and support the view that OECs have multiple attributes favorable for enhancing axonal extension and neuronal migration after central nervous system injury. J. Comp. Neurol. 458:175–194, 2003. © 2003 Wiley‐Liss, Inc.
Insulin‐like growth factor‐II/mannose‐6‐phosphate receptor: Widespread distribution in neurons of the central nervous system including those expressing cholinergic phenotype
Authors: Hawkes Cheryl , Kar Satyabrata 
Published: February 2003

AbstractThe insulin‐like growth factor‐II/mannose‐6‐phosphate (IGF‐II/M6P) receptor is single transmembrane glycoprotein that plays a critical role in the trafficking of lysosomal enzymes and the internalization of circulating IGF‐II. At present, there is little information regarding the cellular distribution of the IGF‐II/M6P receptor within the adult rat brain. With the use of immunoblotting and immunocytochemical methods, we found that the IGF‐II/M6P receptor is widely but selectively expressed in all major brain areas, including the olfactory bulb, striatum, cortex, hippocampus, thalamus, hypothalamus, cerebellum, brainstem, and spinal cord. Intense IGF‐II/M6P receptor immunoreactivity was apparent on neuronal cell bodies within the striatum, deeper layers (layers IV and V) of the cortex, pyramidal and granule cell layers of the hippocampal formation, selected thalamic nuclei, Purkinje cells of the cerebellum, pontine nucleus and motoneurons of the brainstem as well as in the spinal cord. Moderate neuronal labeling was evident in the olfactory bulb, basal forebrain areas, hypothalamus, superior colliculus, midbrain areas, granule cells of the cerebellum and in the intermediate regions of the spinal gray matter. We also observed dense neuropil labeling in many regions, suggesting that this receptor is localized in dendrites and/or axon terminals. Double‐labeling studies further indicated that a subset of IGF‐II/M6P receptor colocalizes with cholinergic cell bodies and fibers in the septum, striatum, diagonal band complex, nucleus basalis, cortex, hippocampus, and motoneurons of the brainstem and spinal cord. The observed widespread distribution and colocalization of IGF‐II/M6P receptor in the adult rat brain provide an anatomic basis to suggest a multifunctional role for the receptor in a wide‐spectrum of central nervous system neurons, including those expressing a cholinergic phenotype. J. Comp. Neurol. 458:113–127, 2003. © 2003 Wiley‐Liss, Inc.
Distribution of dendrites of descending neurons and its implications for the basic organization of the cockroach brain
Authors: Okada Ryuichi , Sakura Midori , Mizunami Makoto 
Published: February 2003

AbstractTo determine precisely the brain areas from which descending neurons (DNs) originate, we examined the distribution of somata and dendrites of DNs in the cockroach brain by retrogradely filling their axons from the cervical connective. At least 235 pairs of somata of DNs were stained, and most of these were grouped into 22 clusters. Their dendrites were distributed in most brain areas, including lateral and medial protocerebra, which are major termination areas of output neurons of the mushroom body, but not in the optic and antennal lobes, the mushroom body, the central complex, or the posteroventral part of the lateral horn. The last area is the termination area of major types of olfactory projection neurons from the antennal lobe, i.e., uni‐ and macroglomerular projection neurons, so these neurons have no direct connections with DNs. The distribution of axon terminals of ascending neurons overlaps with that of DN dendrites. We propose, based on these findings, that there are numerous parallel processing streams from cephalic sensory areas to thoracic locomotory centers, many of which are via premotor brain areas from which DNs originate. In addition, outputs from the mushroom body, central complex, and posteroventral part of the lateral horn converge on some of the premotor areas, presumably to modulate the activity of some sensorimotor pathways. We propose, based on our results and documented findings, that many parallel processing streams function in various forms of reflexive and relatively stereotyped behaviors, whereas indirect pathways govern some forms of experience‐dependent modification of behavior. J. Comp. Neurol. 458:158–174, 2003. © 2003 Wiley‐Liss, Inc.
Troglitazone‐induced intracellular oxidative stress in rat hepatoma cells: A flow cytometric assessment
Authors: Narayanan Padma Kumar , Hart Timothy , Elcock Fiona , Zhang Cindy , Hahn Laura , McFarland David , Schwartz Lester , Morgan D. Gwyn , Bugelski Peter 
Published: February 2003

AbstractBackgroundTroglitazone (TRO), a thiazolidinedione (TZD) peroxisome proliferator‐activated receptor γ agonist, was recently withdrawn from the market because of rare but serious hepatotoxicity. Previous studies investigating the cytotoxicity of TRO in cultured rat hepatocytes have conjectured about the role of oxidative stress in TRO‐induced hepatotoxicity. Therefore, we investigated whether TRO induces oxidative stress and, if so, the portion of the TRO molecule responsible for the induction of oxidative stress.MethodsNovikoff rat hepatoma (N1S1) cells were incubated with TRO, troglitazone quinone (TQ), thiazolidinedione‐phenoxyacetic acid (TD‐PAA) or rosiglitazone (RSG). Membrane peroxidation, intracellular glutathione (GSH) content, and cellular viability were monitored simultaneously by multiparameter flow cytometry.ResultsTRO and TQ increased membrane peroxidation, decreased intracellular GSH, and decreased cell viability in a concentration‐dependent manner. In contrast, TD‐PAA and RSG neither increased membrane peroxidation nor induced loss of cell viability. In addition, TRO caused a concentration‐dependent increase in intracellular superoxide generation accompanied by a collapse in mitochondrial membrane potential.ConclusionMultiparameter flow cytometric evaluation of N1S1 cells indicated that the chromane ring of TRO, rather than the TZD moiety, may be responsible for oxidative stress and suggested that a direct effect on mitochondrial physiology may play a role in TRO‐mediated hepatotoxicity. Cytometry Part A 52A:28–35, 2003. © 2003 Wiley‐Liss, Inc.
Toluidine blue test for sperm DNA integrity and elaboration of image cytometry algorithm
Authors: Erenpreisa Jekaterina , Erenpreiss Juris , Freivalds Talivaldis , Slaidina Maija , Krampe Rasma , Butikova Jelena , Ivanov Andrey , Pjanova Dace 
Published: February 2003

AbstractBackgroundSperm DNA integrity is of paramount importance in the prognosis of fertility. We applied image cytometry to a toluidine blue (TB) test we recently proposed.MethodsSperm samples from 33 men were assayed for standard sperm parameters and classified as normal or abnormal. Sperm smears were subjected to the TB test, DNA denaturation testing with acridine orange (AO), and terminal deoxyuridine triphosphate biotin nick end labeling (TUNEL). In CCD image analysis, TB‐stained sperm cell heads were microscopically assigned to one of four color groups (dark, blue, light violet, and light blue). The optical densities of 6,600 cells in green and red CCD images were used to elaborate an algorithm for discrimination of these groups.ResultsThe proportions of sperm in TB color groups, as estimated with the developed image cytometry algorithm, correlated with microscopic features. The number of TB dark cells correlated with the number of AO‐red and TUNEL+ cells. The proportion of TB dark cells in normal samples did not exceed 35%. Light‐blue sperm cell heads prevailed in normal samples, whereas dark and blue sperm cell heads dominated in abnormal samples.ConclusionsThe TB test was suitable for the assessment of sperm cell DNA integrity. The elaborated image cytometry algorithm can be used for this purpose and for finer determination of sperm nucleus status. Cytometry Part A 52A:19–27, 2003. © 2003 Wiley‐Liss, Inc.
Automated analysis of morphometric parameters for accurate definition of erythrocyte cell shape
Authors: Albertini Maria C. , Teodori Laura , Piatti Elena , Piacentini Maria P. , Accorsi Augusto , Rocchi Marco B. L. 
Published: February 2003

AbstractBackgroundModification of erythrocyte morphology is clinically important in hematology and medicine. Its detection is routinely performed by subjective microscopic evaluation, which is difficult and strongly dependent on the operator's expertise. We developed an original automated methodology to analyze erythrocyte cell shape modification to support and improve the operator's capability and expedite measurements.MethodsWe used morphometric parameters derived from optical microscope images elaborated with an image processing software (NIH Scion Image) to construct a new application for statistical multivariate discriminant analysis.ResultsFor each cell type the elaboration of the morphometric parameters allowed us to develop a chromogenic index, a dimension index, a biconcavity index, and a density profile. The measurements of these indexes were used to construct a statistical methodology that could discriminate among erythrocyte morphologies according to Bessis. When applied casewise, the model effectively differentiated between discocytes, target cells, ovalocytes, macrocytes, and microcytes, with an agreement of 70% between actual and predicted classifications.ConclusionsThe results clearly demonstrated that a set of opportunely selected morphometric parameters derived from optical microscope images and statistically analyzed can effectively discriminate with a high degree of certainty among different shape modifications that red blood cells can undergo in various in vitro and in vivo conditions. This method represents the first attempt to automate the definition of erythrocyte morphology and may have important applications in cases in which the detection of erythrocyte cell shape changes is crucial. Cytometry Part A 52A:12–18, 2003. © 2003 Wiley‐Liss, Inc.
Fluorescence lifetime‐based discrimination and quantification of cellular DNA and RNA with phase‐sensitive flow cytometry
Authors: Cui H. Helen , Valdez Joseph G. , Steinkamp John A. , Crissman Harry A. 
Published: February 2003

AbstractBackgroundSimultaneous measurement of cellular DNA and RNA content provides information for determination of the functional status of cells and, clinically, for the diagnosis and grading assessment of various tumors. Most current flow cytometric methods are based on resolving the fluorescence emission spectra of dyes that bind preferentially to either type of nucleic acid. However, several monochromatic nucleic acid–binding fluorochromes display resolvable differences in fluorescence lifetime when bound to DNA or RNA. The differences in the lifetime of one fluorescent probe provide an alternate means to distinguish the binding of one probe to these cellular macromolecules and to simultaneously measure their cellular contents.MethodsThree nucleic acid intercalating dyes, propidium iodide, ethidium bromide, and ethidium homodimer 1, were selected to study differences in fluorescence lifetimes when bound to cellular DNA and RNA. Fixed HL‐60 cells were treated with specific nucleases to initially determine the lifetime values of each dye when bound to the cellular DNA, RNA, or both. The lifetime values were then used as the signatures to resolve the cellular DNA and RNA contents in untreated cells.ResultsAll three dyes showed fluorescence lifetime differences when bound to RNase‐treated, DNase‐treated, or untreated cells. With these lifetime values, the fluorescence emissions from DNA, RNA, or DNA/RNA were resolved from untreated cells with the use of phase‐sensitive detection. The lifetime differences resulting from the binding to either type of nucleic acid depended on the dye, the staining concentration, and the analysis condition.ConclusionsThe lifetimes of the nucleic acid–binding fluorochromes were altered when binding to different macromolecules under different conditions. Phase‐sensitive flow cytometry provided a unique means for simultaneous discrimination and quantification of subcellular macromolecules with one fluorescent probe. The data demonstrated the capabilities for resolving relative cellular DNA and RNA contents based on fluorescence lifetime. Cytometry Part A 52A:46–55, 2003. Published 2003 Wiley‐Liss, Inc.
Comparison of proliferation and rapid cytokine induction assays for flow cytometric T‐cell epitope mapping
Authors: Tesfa Lydia , Volk Hans‐Dieter , Kern Florian 
Published: February 2003

AbstractBackgroundT‐cell epitope mapping by flow cytometry based on rapid ex vivo peptide‐specific cytokine induction in T cells is very efficient and time saving compared with traditional assays. We investigated whether the same epitopes could be identified by proliferation studies.MethodsAn assay based on rapid interferon‐γ induction in T cells (6 h of ex vivo stimulation) was run in parallel with a proliferation assay based on the incremental loss of carboxy‐fluorescein diacetate succinimidyl ester staining in proliferating cells. The proliferation assay was chosen because it can be evaluated by high‐resolution modern multiparameter flow cytometry. In both cases, T cells were stimulated with the same cytomegalovirus‐derived peptides. The peptides identified by the rapid induction of interferon‐γ were compared with those inducing T‐cell proliferation.ResultsMost epitopes were identified by proliferation and rapid cytokine induction methods; however, each method also identified epitopes that the other one did not. In general, rapid cytokine induction was associated with considerably less background noise, making epitope identification easier, and, owing to the short stimulation time necessary, several identification steps could be carried out on material stored in the incubator.ConclusionsEven though most epitopes were identified by both approaches, the rapid cytokine induction method had major logistic advantages. However, it may be best to use both assays, particularly in situations in which the identification of epitopes may depend on prior clonal T‐cell expansion. Cytometry Part A 52A:36–45, 2003. © 2003 Wiley‐Liss, Inc.
Quantitative image analysis of cellular protein translocation induced by magnetic microspheres: Application to the EGF Receptor
Authors: Brock Roland , Jovin Thomas M. 
Published: February 2003

AbstractBackgroundThe molecular analysis of intracellular signal transduction requires technologies that address quantitatively the activation of signaling proteins and formation of molecular complexes without disrupting cellular integrity.MethodsCells expressing the epidermal growth factor receptor (EGFR) in its endogenous form or fused to green fluorescent protein were incubated with 1‐μm microspheres covalently functionalized with EGF. The disposition of the plasma membrane about the microspheres was analyzed by high‐resolution confocal microscopy in combination with computational resolution enhancement and optimized fixation procedures. Receptor activation and translocation of signaling proteins to the microspheres was quantitated by image processing protocols for recovering the microsphere‐associated fluorescence and the fluorescence in the local environment.ResultsEGF‐functionalized microspheres were internalized in an activation‐dependent manner similar to that of the soluble growth factor. The correlation of receptor activation and recruitment of a signaling protein was analyzed quantitatively by isolating immunofluorescence signals from the microspheres and from their immediate environment.ConclusionsThe microsphere‐based approach provides a quantitative analysis of cellular signal transduction with subcellular resolution under conditions maintaining cellular integrity. The analysis of signaling‐induced (co)localization of proteins around a microsphere complements other technologies directly probing for molecular interactions such as fluorescence resonance energy transfer. Cytometry Part A 52A:1–11, 2003. © 2003 Wiley‐Liss, Inc.
The Strained η2‐NAmido−NPyridine Coordination of Aminopyridinato Ligands
Authors: Kempe Rhett 
Published: February 2003

AbstractThis review gives an account of the syntheses and structures of group‐3 (including lanthanides), ‐4 and ‐5 metal complexes stabilised by strained η2‐coordinated aminopyridinato ligands. Reactivity studies and catalytic applications of the coordination compounds are discussed. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Cyclodextrin‐Encapsulated Iron Catalysts for the Polymerization of Ethylene
Authors: Armspach Dominique , Matt Dominique , Peruch Frédéric , Lutz Pierre 
Published: February 2003

AbstractThe synthesis and characterization of dichloroiron(II) complexes of tridentate nitrogen ligands based on 2,6‐bis(imino)pyridine‐capped α‐ and β‐cyclodextrin derivatives are described and their propensity to act as ethylene polymerization catalysts reported. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
TiIV Complexes with Novel, Chiral, Tridentate Amido‐Amidinate or Monoanionic, Didentate Amidinate Ligands
Authors: Li Jian‐Feng , Huang Shu‐Ping , Weng Lin‐Hong , Liu Dian‐Sheng 
Published: February 2003

AbstractReaction of LiL or a new type of dianionic ligand Li2L (2) {H2L = (1R,2R)‐(−)‐1‐[N(H)C(Ph)N(SiMe3)]‐2‐[N(H)SiMe3]C6H10} with TiCl2(OiPr)2 yielded the novel complexes [TiCl(L)(OiPr)2] (1) and [Ti(L)(OiPr)2] (3), respectively. Treatment of Na2L′ {H2L′ = (1R,2R)‐(−)‐1,2‐[N(H)C(Ph)N(SiMe3)]2C6H10]} with Ti(OiPr)2Cl2 unexpectedly gave 3 via a unusual rearrangement/elimination reaction; The structure of complex 3 shows both an η3‐π bond and σ‐bonds to the central metal. This is a new coordination model and is obtained for the first time for this type of amido‐amidinate complex. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Tellurium(II) Dialkanethiolates: np(S)‐σ*(Te−S′) Orbital Interactions Determine the 125Te NMR Chemical Shift, and the Molecular and Crystal Structure
Authors: Fleischer Holger , Mitzel Norbert W. , Schollmeyer Dieter 
Published: February 2003

AbstractTellurium(II) dimethanethiolate, Te(SMe)2, and tellurium(II) diethanethiolate, Te(SEt)2, were synthesized by reaction of TeO2 and Te(OiPr)4 with HSMe and HSEt, respectively. In the solid state, Te(SMe)2 exhibits a cis‐conformation of the methyl groups with respect to the TeS2 plane − an unprecedented situation for nonfunctionalized organotrichalcogenides − whereas Te(SEt)2 shows a trans‐conformation. Ab initio calculations performed for Te(SMe)2 and Te(SEt)2 show that the cis‐ and trans‐conformers represent minima on the potential energy surface and are stabilized by intramolecular π‐type n(S)‐σ*(Te−S′) orbital interactions. In the solid state, the molecules of each compound are associated through two centrosymmetric Te2S2 units with two of their neighbors, resulting in tetracoordinate Te atoms with distorted trapezoidal configurations. While the intermolecular Te···S distance increases in the sequence R = Me < Et < iPr < tBu, the length of the covalent Te−S bond decreases in the same order, a result attributed to intermolecular σ‐type np(S)‐σ*(Te−S′) orbital interactions. The 125Te NMR chemical shift of Te(SR)2 largely depends on R (R = Me, Et, iPr, tBu) and shows a nearly linear correlation with the first ionization energy of the corresponding thiol HSR. Ab initio calculations of the 125Te NMR shifts for the model compound Te(SH)2 (C2 symmetry) reveal that it also depends strongly on the HSTeS torsion angle. These results can be explained by a model in which π‐type np(S)‐σ*(Te−S′) and np(Te)‐σ*(S−H) orbital interactions determine the paramagnetic shielding of the tellurium nucleus. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Synthesis of Tetrahemispheraplexes with Ammonium, Alkylammonium or Alkaline Metal Ions as Exohedral Guests via Self‐Assembly or Guest Exchange
Authors: Saalfrank Rolf W. , Demleitner Bernhard , Glaser Horst , Maid Harald , Reihs Stefan , Bauer Walter , Maluenga Monica , Hampel Frank , Teichert Markus , Krautscheid Harald 
Published: February 2003

AbstractTo study the interplay between the steric demand of the guest and the space available at the host, we have prepared the tetraammonium complexes {(NH4)4∩[Mg4(L1/2)6]} 1, tetrakis(methylammonium) complexes {(Me‐NH3)4∩[Mg4(L1/2)6]} 2, tetrakis(ethylammonium) complex {(Et‐NH3)4∩[Mg4(L1)6]} 3, and mixed sodium tris(ethylammonium) complex {Na(Et‐NH3)3∩[Mg4(L2)6]} 4. The tetrahemispheraplexes 1−4 were available in one‐pot syntheses. The tetrakis(alkylammonium) clusters {(R1−NH3)4∩[Mg4(L1)6]} 5 and the mixed diammonium‐bis(p‐methoxybenzylammonium) cluster {(NH4)2(R2−NH3)2∩[Mg4(L1)6]} 6, however, were prepared by exchange of the ammonium ions of 1a by alkylammonium ions. Similarly, exchange of the four ammonium ions of 1b by alkaline metal cations afforded the tetraalkaline metal tetrahemispheraplexes {M4∩[Mg4(L2)6]} 7. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)