bluuebunny/crossref_metadata_2025_split huggingface dataset:
On‐line confocal imaging of the events leading to structural dedifferentiation of an axonal segment into a growth cone after axotomy
Authors: Sahly Iman , Khoutorsky Arkady , Erez Hadas , Prager‐Khoutorsky Masha , Spira Micha E. 
Published: December 2005

AbstractThe transformation of a transected axonal tip into a growth cone (GC) after axotomy is a critical step in the cascade of events leading to regeneration. However, the mechanisms underlying it are largely unknown. In earlier studies we reported that axotomy of cultured Aplysia neurons leads to a transient and local increase in the free intracellular Ca2+ concentration, calpain activation, and localized proteolysis of the submembranal spectrin. In a recent ultrastructural study, we reported that calpain activation is critical for the restructuring of the microtubules and neurofilaments at the cut axonal end to form a compartment in which vesicles accumulate. By using on‐line confocal imaging of microtubules (MTs), actin, and vesicles in cultured Aplysia neurons, we studied the kinetics of the transformation and examined some of the mechanisms that orchestrate it. We report that perturbation of the MTs' polymerization by nocodazole inhibits the formation of an MT‐based compartment in which the vesicles accumulate, yet actin repolymerization proceeds normally to form a nascent GC's lamellipodium. Nevertheless, under these conditions, the lamellipodium fails to expand and form neurites. When actin filament polymerization is inhibited by cytochalasin D or jasplakinolide, the MT‐based compartment is formed and vesicles accumulate at the cut axonal end. However, a GC's lamellipodium is not formed, and the cut axonal end fails to regenerate. A growth‐competent GC is formed only when MT restructuring, the accumulation of vesicles, and actin polymerization properly converge in time and space. J. Comp. Neurol. 494:705–720, 2006. © 2005 Wiley‐Liss, Inc.
Mapping glutamate responses in immunocytochemically identified neurons of the mouse retina
Authors: Sun Daniel , Kalloniatis Michael 
Published: December 2005

AbstractThe mammalian retina contains as many as 50–60 unique cell types, many of which have been identified using various neurochemical markers. Retinal neurons express N‐methyl‐D‐aspartate (NMDA), α‐amino‐3‐hydroxyl‐5‐methylisoxazole‐4‐propionic acid (AMPA), and kainic acid (KA) receptor subunits in various mixtures, densities, and spatial distributions. Ionotropic glutamatergic drive in retinal neurons can be mapped using a cation channel permeant guanidinium analog called agmatine (1‐amino‐4‐guanidobutane; AGB). This alternative approach to physiologically characterize neurons in the retina was introduced by Marc (1999, J Comp Neurol 407:47–64, 407:65–76), and allows the simultaneous mapping of responses of glutamate receptor‐gated channels from an entire population of neurons. Unlike previous AGB studies, we colocalized AGB with various macromolecular markers using direct and indirect immunofluorescence to characterize the glutamate agonist sensitivities of specific cell types. Activation with NMDA, AMPA, and KA resulted in AGB entry into neurons in a dose‐dependent manner and was consistent with previous receptor subunit localization studies. Consistent with the various morphological phenotypes encompassed by the calbindin and calretinin immunoreactive cells, we observed various functional phenotypes revealed by AGB labeling. Not all calbindin or calretinin immunoreactive cells showed ligand‐evoked AGB permeation. A small proportion either did not possess functional glutamate receptors, required higher activation thresholds, or express functional channels impermeable to AGB. AMPA and KA activation of bipolar cells resulted in AGB permeation into the hyperpolarizing variety only. We also studied the glutamate ligand‐gating properties of 3[α1‐3]‐fucosyl‐N‐acetyl‐lactosamine (CD15) immunoreactive cells and show functional responses consistent with receptor subunit gene expression patterns. CD15‐immunoreactive bipolar cells only responded to AMPA but not KA. The CD15 immunoreactive amacrine cells demonstrated an identical selectivity to AMPA activation, but were also responsive to NMDA. Finally, localization of AGB secondary to glutamate receptor activation was visualized with a permanent reaction product. J. Comp. Neurol. 494:686–703, 2006. © 2005 Wiley‐Liss, Inc.
A phylotypic stage in vertebrate brain development: GABA cell patterns in zebrafish compared with mouse
Authors: Mueller Thomas , Vernier Philippe , Wullimann Mario F. 
Published: December 2005

AbstractA recent comparison of early forebrain gene expression in mouse and zebrafish revealed highly comparable expression patterns of developmentally relevant genes, for example, of proneural (Neurogenin1, NeuroD, Mash1/Zash1a) genes involved in neurogenesis at a particular time window (mouse: embryonic day 12.5/13.5; zebrafish: 3 days). Here we extend this analysis to the description of γ‐aminobutyric acid (GABA) cell patterns in the early postembryonic zebrafish brain (i.e., during early secondary neurogenesis). We find again an astonishing degree of correspondences of GABA cell patterns between zebrafish and mouse during this previously established critical time window, for example, regarding absence of GABA cells in certain forebrain regions (pallium, dorsal thalamus, eminentia thalami) or with respect to the spatiotemporal occurrence of GABA cells (e.g., late cerebellar GABA cells). Furthermore, there is perfect correlation with previously established proneural gene expression patterns (i.e., absence of Mash1/Zash1a gene expression in GABA‐cell‐free forebrain regions) between mouse and zebrafish. The available information in additional vertebrate species, especially in Xenopus, is also highly consistent with our analysis here and suggests that a “phylotypic stage” of neurogenesis during vertebrate brain development may be present. J. Comp. Neurol. 494:620–634, 2006. © 2005 Wiley‐Liss, Inc.
Estrogen receptor‐α distribution in male rodents is associated with social organization
Authors: Cushing Bruce S. , Wynne‐Edwards Katherine E. 
Published: December 2005

AbstractIt has been hypothesized that site‐specific reduction of estrogen receptor‐α (ERα) is associated with the expression of male prosocial behaviors. Specifically, highly social males are predicted to express significantly lower levels of ERα than females and less social males in brain regions associated with prosocial behavior including the bed nucleus of the stria terminalis (BST) and the medial amygdala (MeA). This hypothesis was tested by comparing ERα immunoreactivity (IR) in three species of microtines, the polygynous montane (Microtus montanus) and meadow (M. pennsylvanicus) voles and the monogamous pine vole (M. pinetorum), and two species of cricetines that differ in the extent of social pair‐bond formation, Siberian (Phodopus sungorus) and Djungarian (P. campbelli) hamsters. As predicted, ERα‐IR was sexually dimorphic in the BST and MeA of the highly social species, with females expressing more ERα‐IR cells than males. Male and female montane voles did not differ. Male and female meadow voles differed in the ventromedial hypothalamus, with females expressing more ERα‐IR cells. Male pine voles expressed lower levels of ERα‐IR in the MeA than male montane and meadow voles and in the BST relative to montane males. Male Djungarian hamsters, which show higher levels of parental care, had fewer ERα‐IR cells in the BST than male Siberian hamsters. Results indicate that the distribution of ERα differs relative to the continuum of species‐typical affiliative behavior and supports the hypothesis that ERα has a significant role in regulating species‐specific social organization. J. Comp. Neurol. 494:595–605, 2006. © 2005 Wiley‐Liss, Inc.
Ommatidial type‐specific interphotoreceptor connections in the lamina of the swallowtail butterfly, Papilio xuthus
Authors: Takemura Shin‐Ya , Arikawa Kentaro 
Published: December 2005

AbstractThe eye of the butterfly Papilio xuthus contains a random array of three types of ommatidia (types I–III), each bearing nine photoreceptors, R1–R9. Of the six spectral classes of photoreceptors identified, types I, II, and III ommatidia contain four, three, and two classes, respectively: the ommatidia are thus spectrally heterogeneous. The photoreceptors send their axons to the lamina where, together with some large monopolar cells (LMCs), the nine from a single ommatidium contribute to a module called a lamina cartridge. We recently reported that among different photoreceptor axon terminals visualized by confocal microscopy, the number and length of axon collaterals differ for different spectral receptors, suggesting that lamina circuits are specific for each ommatidial type. Here we studied the distribution of synapse‐like structures in the cartridges, first characterizing a photoreceptor by measuring its spectral sensitivity and then injecting Lucifer yellow (LY). We subsequently histologically identified the type of ommatidium to which the injected photoreceptor belonged, cut serial ultrathin sections of the entire lamina, labeled these with anti‐LY immunocytochemistry, and then localized synapse‐like structures. We found numerous interphotoreceptor contacts both within and between cartridges, the combination of which was again specific for the ommatidial type. R3 and R4, which are green‐sensitive photoreceptors in all ommatidia, have thick axons lacking collaterals. We found that these cells exclusively make contacts with LMCs and not with photoreceptors. We therefore presume that R3 and R4 construct a system for motion vision, whereas other randomly distributed spectral types provide inputs for color vision. J. Comp. Neurol. 494:663–672, 2006. © 2005 Wiley‐Liss, Inc.
Expression pattern of calcitonin gene‐related peptide in the superior colliculus during postnatal development: Demonstration of its intrinsic nature and possible roles
Authors: Gerrikagoitia Inmaculada , del Caño Gontzal García , Canudas Jesús , Sarasa Manuel , Martínez‐Millán Luis 
Published: December 2005

AbstractCalcitonin gene‐related peptide (CGRP) is a widespread neuropeptide with multiple central and peripheral targets. In an analysis on the expression of this peptide throughout the rat brain during postnatal development, we observed a discrepancy between results obtained by immunohistochemistry and by in situ hybridization. In the superior colliculus (SC), only the immunohistochemical signal could be detected (Terrado et al. [1997] Neuroscience 80:951–970). Here we focus our attention on this structure because the temporal pattern of CGRP immunoreactivity observed in the SC suggested the participation of this peptide in the postnatal maturation of the SC. In the present study, we describe in detail the postnatal development of collicular CGRP‐immunoreactive structures and their spatiotemporal relationship with cholinergic modules and definitively demonstrate the local expression of CGRP in the SC. CGRP‐immunopositive axons and neurons were distributed within the most ventral part of superficial strata and in the intermediate strata of the SC, showing a peak in staining intensity and density at the end of the first postnatal week. At P14, CGRPergic terminal fibers are arranged in small, clearly defined patches in a complementary manner with respect to the cholinergic modules, which start forming at this stage. By using Western blot and RT‐PCR analyses, and by means of injections of antisense oligonucleotides, both the presence of CGRP peptide in the SC and the local expression of α‐CGRP transcripts in collicular neurons were demonstrated. A possible role of CGRP is discussed in the context of postnatal modular compartmentalization of collicular afferents. J. Comp. Neurol. 494:721–737, 2006. © 2005 Wiley‐Liss, Inc.
Water deprivation activates a glutamatergic projection from the hypothalamic paraventricular nucleus to the rostral ventrolateral medulla
Authors: Stocker Sean D. , Simmons Johnny R. , Stornetta Ruth L. , Toney Glenn M. , Guyenet Patrice G. 
Published: December 2005

AbstractElevated sympathetic outflow contributes to the maintenance of blood pressure in water‐deprived rats. The neural circuitry underlying this response may involve activation of a pathway from the hypothalamic paraventricular nucleus (PVH) to the rostral ventrolateral medulla (RVLM). We sought to determine whether the PVH‐RVLM projection activated by water deprivation is glutamatergic and/or contains vasopressin‐ or oxytocin‐neurophysins. Vesicular glutamate transporter 2 (VGLUT2) mRNA was detected by in situ hybridization in the majority of PVH neurons retrogradely labeled from the ipsilateral RVLM with cholera toxin subunit B (CTB; 85% on average, with regional differences). Very few RVLM‐projecting PVH neurons were immunoreactive for oxytocin‐ or vasopressin‐associated neurophysin. Injection of biotinylated dextran amine (BDA) into the PVH produced clusters of BDA‐positive nerve terminals within the ipsilateral RVLM that were immunoreactive (ir) for the VGLUT2 protein. Some of these terminals made close appositions with tyrosine‐hydroxylase‐ir dendrites (presumptive C1 cells). In water‐deprived rats (n = 4), numerous VGLUT2 mRNA‐positive PVH neurons retrogradely labeled from the ipsilateral RVLM with CTB were c‐Fos‐ir (16–40%, depending on PVH region). In marked contrast, few glutamatergic, RVLM‐projecting PVH neurons were c‐Fos‐ir in control rats (n = 3; 0–3%, depending on PVH region). Most (94% ± 4%) RVLM‐projecting PVH neurons activated by water deprivation contained VGLUT2 mRNA. In summary, most PVH neurons that innervate the RVLM are glutamatergic, and this population includes the neurons that are activated by water deprivation. One mechanism by which water deprivation may increase the sympathetic outflow is activation of a glutamatergic pathway from the PVH to the RVLM. J. Comp. Neurol. 494:673–685, 2006. © 2005 Wiley‐Liss, Inc.
Astrocytic and neuronal localization of the scaffold protein Na+/H+ exchanger regulatory factor 2 (NHERF‐2) in mouse brain
Authors: Paquet Maryse , Kuwajima Masaaki , Yun C. Chris , Smith Yoland , Hall Randy A. 
Published: December 2005

AbstractThe Na+/H+ exchanger regulatory factor 2 (NHERF‐2) is a scaffold protein that regulates cellular signaling by forming protein complexes. Several proteins known to interact with NHERF‐2 are abundantly expressed in the central nervous system, but little is known about NHERF‐2 localization in the brain. By using immunohistochemistry combined with light and electron microscopy, we found that many populations of astrocytes, as well as some populations of neurons, were immunopositive for NHERF‐2 throughout the mouse brain. Quantitative analysis of the subcellular distribution of NHERF‐2 immunostaining in four brain structures, cerebral cortex, hippocampus, striatum, and cerebellar cortex, showed that NHERF‐2 was expressed mainly in astrocytic processes but was also sometimes observed in both pre‐ and postsynaptic neuronal elements. NHERF‐2 immunostaining was associated mainly with the plasma membrane of neurons and astrocytes. However, NHERF‐2 immunoreactivity was also observed in association with synaptic vesicles in putative glutamatergic axon terminals. The subcellular localization of NHERF‐2 in brain is consistent with a role for NHERF‐2 in forming complexes between cell surface and cytosolic proteins, and the preferential expression of NHERF‐2 in astrocytes suggests that this scaffold protein may play an important role in astrocytic physiology. J. Comp. Neurol. 494:752–762, 2006. © 2005 Wiley‐Liss, Inc.
New Insights into the Redox Chemistry of Ruthenium Metallopharmaceuticals: The Electrochemical Behaviour of [LH][trans‐RuIIICl4L2] (L = imidazole or indazole) Complexes
Authors: Ravera Mauro , Cassino Claudio , Baracco Sara , Osella Domenico 
Published: December 2005

AbstractHere we report the findings from a study on the electrochemical behaviour of two RuIII complexes [LH][trans‐RuIIICl4L2] (L = imidazole, ICR, or indazole, IndCR) in aqueous solution at different pH values. An electrochemically reversible and chemically quasi‐reversible one‐electron reduction is observed for both compounds. Despite the similarity of the structures, the fate of the electrogenerated RuII species is different; in the case of ICR, imidazole, followed by a chloride ion, is released as the consequence of the reduction, while for IndCR two subsequent water for chloride substitutions take place. Our measurements suggests that the RuIII complexes under study may serve as pro‐drugs, being activated by reduction in a suitable aqueous environment and, therefore, binding biomolecules more rapidly. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Entrapment of a Hexamer of Nitrobenzene Molecules between the Layers of (4,4)‐Coordination Networks Containing Intra‐β‐Sheet Hydrogen Bonds
Authors: Sarkar Madhushree , Biradha Kumar 
Published: December 2005

AbstractTwo exo‐bidentate pyridyl ligands containing diamides as spacers were shown to form non‐interpenetrated 2D‐coordination networks of (4,4)‐geometry upon treatment with Cu(NO3)2 and NaSCN. The crystal structures reveal that both structures contain intralayer β‐sheet hydrogen bonds. In one of these structures nitrobenzene occupies 60 % of the crystal volume included between the coordination networks. The nitrobenzene molecules form a layer which has the hexameric C–H···O hydrogen bonded aggregate as a basic building block. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Crystal Structure and Optical Properties of a Lanthanum(III) Complex of the Solvatochromic Dye “Nile Red” (Eur. J. Inorg. Chem. 1/2006)
Authors: Døssing Anders , Magnussen Magnus , Frey Anne Mette 
Published: December 2005

AbstractThe cover picture shows that addition of lanthanum(III) triflate to the red solution of a fluorescent “Nile Red” derivative results in a bathochromic shift of the intense charge‐transfer band due to the formation of a chelate lanthanum(III) complex, as shown by a structure determination of crystals isolated from the resulting blue solution. details are discussed in the Short Communication by A. Døssing et al. on p. 43 ff.
Synthetic and Structural Studies of Silver(I)‐ and Gold(I)‐ContainingN‐Heterocyclic Carbene Metallacrown Ethers
Authors: Wang Jun‐Wen , Li Qing‐Shan , Xu Feng‐Bo , Song Hai‐Bin , Zhang Zheng‐Zhi 
Published: December 2005

AbstractThe ligands bis(imidazolium) hexafluorophosphate [RHimy‐(CH2OCH2)n‐HimyR][PF6]2 [Himy = –C3N2H3–, imidazolium; R = 1‐naphthylmethyl, n = 2 (1a), 3 (2a); R = 9‐anthracenylmethyl, n = 2 (1b), 3 (2b)] with a highly flexible polyether chain were easily prepared by the reaction of substituted imidazole with the corresponding polyglycol diiodide, followed by exchange of the anions with PF6–. Ligands 1a,b and 2a,b react with Ag2O to give monometallic AgI‐containing N‐heterocyclic carbene (NHC) metallacrown ethers 3a,b and 4a,b with a long and highly flexible bridging chain (CH2OCH2)n (n = 2, 3) between the two imidazolium units. Complexes 3a,b and 4a,b react with [Au(SMe2)Cl] in a transmetalation reaction to give AuI analogues 5a,b and 6a,b. Complexes 3a,b–6a,b are novel examples of a metallacrown ether with NHCs. In contrast to the use of a high‐dilution technique in the preparation of polyether chain phosphane‐containing metallacrown ethers, the new trans‐metallacrown ethers can be prepared in concentrated solution. The structures of 3a–6a were confirmed by X‐ray diffraction determination. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Moore Cyclizations: Rearrangements of 3‐Heteroatom‐pent‐1‐en‐4‐yn‐1‐ones – A Computational Search for New Reactions
Authors: Schreiner Peter R. , Bui Binh H. 
Published: December 2005

AbstractThe thermal rearrangements of 3‐heteroatom‐pent‐1‐en‐4‐yn‐1‐ones were studied at the BLYP/6‐311+G*//BLYP/6‐31G* level of theory. While cyclizations to oxo‐hetero‐cyclopentadien‐di‐yl are most favorable and predicted to be experimentally feasible for X = CH–, NH, O, and S, protonation of these substituents raises the corresponding 2,6‐cyclization barriers. Cyclizations to oxacyclohexadienediyl are highly improbable due to competition with other low‐lying alternative pathways. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Polystyrene‐Supported 1,5,7‐Triazabicyclo[4.4.0]dec‐5‐ene as an Efficient and Reusable Catalyst for the Thiolysis of 1,2‐Epoxides under Solvent‐Free Conditions
Authors: Fringuelli Francesco , Pizzo Ferdinando , Vittoriani Carla , Vaccaro Luigi 
Published: December 2005

AbstractPolystyrene‐supported 1,5,7‐triazabicyclo[4.4.0]dec‐5‐ene (PS‐TBD) is an effective basic catalyst for the thiolysis of the 1,2‐epoxides 1a–e by the aryl‐ and alkyl‐substituted thiols 2A–E under solvent‐free conditions while its activity is remarkably reduced in MeCN. The reactions are totally anti‐diastereoselective and generally highly C‐β regioselective. The corresponding hydroxy sulfides have been isolated in excellent yields and the catalyst has been easily recovered and reused with no loss in terms of efficiency and selectivity of the process. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Family‐based association test for time‐to‐onset data with time‐dependent differences between the hazard functions
Authors: Jiang Hongyu , Harrington David , Raby Benjamin A. , Bertram Lars , Blacker Deborah , Weiss Scott T. , Lange Christoph 
Published: December 2005

AbstractIn genetic association studies, the differences between the hazard functions for the individual genotypes are often time‐dependent. We address the non‐proportional hazards data by using the weighted logrank approach by Fleming and Harrington [1981]:Commun Stat‐Theor M 10:763–794. We introduce a weighted FBAT‐Logrank whose weights are based on a non‐parametric estimator for the genetic marker distribution function under the alternative hypothesis. We show that the computation of the marker distribution under the alternative does not bias the significance level of any subsequently computed FBAT‐statistic. Hence, we use the estimated marker distribution to select the Fleming‐Harrington weights so that the power of the weighted FBAT‐Logrank test is maximized. In simulation studies and applications to an asthma study, we illustrate the practical relevance of the new methodology. In addition to power increases of 100% over the original FBAT‐Logrank test, we also gain insight into the age at which a genotype exerts the greatest influence on disease risk. Genet. Epidemiol. 2006. © 2006 Wiley‐Liss, Inc.