bluuebunny/crossref_metadata_2025_split huggingface dataset:
Gonadal hormone modulation of hippocampal neurogenesis in the adult
Authors: Galea Liisa A.M. , Spritzer Mark D. , Barker Jennifer M. , Pawluski Jodi L. 
Published: January 2006

AbstractGonadal hormones modulate neurogenesis in the dentate gyrus (DG) of adult rodents in complex ways. Estradiol, the most potent estrogen, initially enhances and subsequently suppresses cell proliferation in the dentate gryus of adult female rodents. Much less is known about how estradiol modulates neurogenesis in the adult male rodent; however, recent evidence suggests that estradiol may have a moderate effect on cell proliferation but enhances cell survival in the DG of newly synthesized cells but only when estradiol is administered during a specific stage in the cell maturation cycle in the adult male rodent. Testosterone likely plays a role in adult neurogenesis, although there have been no direct studies to address this. However, pilot studies from our laboratory suggest that testosterone up‐regulates cell survival but not cell proliferation in the DG of adult male rats. Progesterone appears to attenuate the estradiol‐induced enhancement of cell proliferation. Neurosteroids such as allopregnalone decrease neurogenesis in adult rodents, while pregnancy and motherhood differentially regulate adult neurogenesis in the adult female rodent. Very few studies have investigated the effects of gonadal hormones on male rodents; however, studies have indicated that there is a gender difference in the response to hormone‐regulated hippocampal neurogenesis in the adult. Clearly, more work needs to be done to elucidate the effects of gonadal hormones on neurogenesis in the DG of both male and female rodents. © 2006 Wiley‐Liss Inc.
Stress and adult neurogenesis
Authors: Mirescu Christian , Gould Elizabeth 
Published: January 2006

AbstractStress hormones have potent growth‐inhibiting effects on a variety of peripheral tissues. Consistent with this general function, stress has been shown to inhibit cell proliferation and, ultimately, neurogenesis in the hippocampus. This effect appears to be common across mammalian species, life stages, and most types of stressors. Although some evidence points to a role for glucocorticoids in mediating this effect, contradictory data exist. This review considers the growing literature on this subject with specific emphasis on paradoxical findings and the role of glucocorticoids in modulating adult neurogenesis. © 2006 Wiley‐Liss, Inc.
Environmental enrichment and voluntary exercise massively increase neurogenesis in the adult hippocampus via dissociable pathways
Authors: Olson Andrea K. , Eadie Brennan D. , Ernst Carl , Christie Brian R. 
Published: January 2006

AbstractEnvironmental enrichment (EE) and voluntary exercise (VEx) have consistently been shown to increase adult hippocampal neurogenesis and improve spatial learning ability. Although it appears that these two manipulations are equivalent in this regard, evidence exists that EE and VEx affect different phases of the neurogenic process in distinct ways. We review the data suggesting that EE increases the likelihood of survival of new cells, whereas VEx increases the level of proliferation of progenitor cells. We then outline the factors that may mediate these relationships. Finally, we provide a model showing that VEx leads to the convergence of key somatic and cerebral factors in the dentate gyrus (DG) to induce cell proliferation. Although insufficient evidence exists to provide a similar model for EE, we suggest that EE‐induced cell survival in the DG involves cortical restructuring as a means of promoting survival. We conclude that EE and VEx lead to an increase in overall hippocampal neurogenesis via dissociable pathways, and should therefore, be considered distinct interventions with regard to hippocampal plasticity and associated behaviors. © 2006 Wiley‐Liss, Inc.
Opiates, psychostimulants, and adult hippocampal neurogenesis: Insights for addiction and stem cell biology
Authors: Eisch Amelia J. , Harburg Gwyndolen C. 
Published: January 2006

AbstractOnce thought to produce global, nonspecific brain injury, drugs of abuse are now known to produce selective neuroadaptations in particular brain regions. These neuroadaptations are being closely examined for clues to the development, maintenance, and treatment of addiction. The hippocampus is an area of particular interest, as it is central to many aspects of the addictive process, including relapse to drug taking. A recently appreciated hippocampal neuroadapation produced by drugs as diverse as opiates and psychostimulants is decreased neurogenesis in the subgranular zone (SGZ). While the role of adult‐generated neurons is not clear, their functional integration into hippocampal circuitry raises the possibility that decreased adult SGZ neurogenesis may alter hippocampal function in such a way as to maintain addictive behavior or contribute to relapse. Here, we review the impact of opiates and psychostimulants on the different stages of cell development in the adult brain, as well as the different stages of the addictive process. We discuss how examination of drug‐induced alterations of adult neurogenesis advances our understanding of the complex mechanisms by which opiates and psychostimulants affect brain function while also opening avenues for novel ways of assessing the functional role of adult‐generated neurons. In addition, we highlight key discrepancies in the field and underscore the necessity to move “beyond BrdU”––beyond merely counting new hippocampal cells labeled with the S phase marker bromodeoxyuridine––so as to probe mechanistic questions about how drug‐induced alterations in adult hippocampal neurogenesis occur and what the functional ramifications of alterations in neurogenesis are for addiction. © 2006 Wiley‐Liss, Inc.
Inhibition of neurogenesis interferes with hippocampus‐dependent memory function
Authors: Winocur Gordon , Wojtowicz J. Martin , Sekeres Melanie , Snyder Jason S. , Wang Sabrina 
Published: January 2006

AbstractRats treated with low dose irradiation, to inhibit adult hippocampal neurogenesis, and control rats were administered a nonmatching‐to‐sample (NMTS) task, which measured conditional rule learning and memory for specific events, and a test of fear conditioning in which a discrete CS was paired with an aversive US in a complex environment. Irradiated rats were impaired on the NMTS task when the intervals between sample and test trials were relatively long, and in associating the shock‐induced fear with contextual cues in the fear conditioning task. Irradiated rats were not impaired in learning the basic NMTS rule or in performing that task when the intervals between the sample and test trials were short. Nor were there group differences in conditioning the fear response to the CS in the fear conditioning task. The results, which extend the range of hippocampus‐dependent tasks that can be said to be vulnerable to the effects of neurogenesis suppression, support the hypothesis that new hippocampal cells generated in adulthood participate in a broad range of hippocampal functions. © 2006 Wiley‐Liss, Inc.
Gangliosides of the nuclear membrane: A crucial locus of cytoprotective modulation
Authors: Ledeen Robert W. , Wu Gusheng 
Published: January 2006

AbstractThe original concept of gangliosides as localized components of the plasma membrane has broadened in recent years with recognition of their presence in various intracellular pools as well. The nuclear envelope (NE), consisting of two unique membranes, is one such structure shown to contain members of the gangliotetraose family and possibly other sialoglycolipids. GM1 situated in the inner membrane of the NE is tightly associated with a Na+/Ca2+exchanger whose activity it potentiates in the transfer of Ca2+from nucleoplasm to the NE lumen. This is in contrast to Na+/Ca2+exchangers of the plasma membrane which bind GM1 less avidly or not at all. This is believed due to different isoforms of exchanger, and a difference in topology of the exchanger relative to GM1. Cultured neurons from mice genetically engineered to lack gangliotetraose gangliosides such as GM1 were highly vulnerable to Ca2+‐induced apoptosis. They were rescued to some extent by GM1 but more effectively by LIGA‐20, a membrane‐permeant derivative of GM1 that traverses the plasma membrane more effectively than GM1 and inserts into the NE. As further indication of Ca2+dysregulation, the mutant mice were highly susceptible to kainite‐induced seizures which were attenuated by LIGA‐20. This correlated with the ability of LIGA‐20 to cross the blood–brain barrier, enter brain cells, insert into the NE, and potentiate the nuclear exchanger. GM1 in the NE, in association with nuclear Na+/Ca2+exchanger, is thus seen as contributing to Ca2+regulation within the nucleus and in the process exerting a cytoprotective role. J. Cell. Biochem. 97: 893–903, 2006. © 2006 Wiley‐Liss, Inc.
Quantum‐chemical derivation of electro‐optical parameters for alkanes
Authors: Smirnov Konstantin S. , Bougeard Daniel 
Published: January 2006

AbstractAn approach for deriving the bond electro‐optical parameters (EOPs) of the bond polarizability model (BPM) from quantum‐chemical calculations is proposed. The approach was used to obtain the equilibrium and valence EOPs for the CH and CC bonds in saturated hydrocarbons from the results of the DFT calculations of small chain alkanes. The parameters derived are in the range of those found in the literature. The results of the study show that for this class of molecules the polarizability tensor can be constructed as the sum of the individual bond polarizability tensors thus indicating the validity of the BPM. The use of the parameters in the calculation of the Raman activity of the normal modes of 2‐methylbutane shows a good correlation between the data obtained in the DFT calculations and those with the BPM. Factors influencing the reliability and transferability of the parameters are discussed. Copyright © 2006 John Wiley & Sons, Ltd.
Vibrational spectroscopic studies, conformations and quantum chemical calculations of 3,3,3‐trifluoropropyl‐ silane and 3,3,3‐trifluoropropylsilane‐d3
Authors: Klaeboe Peter , Guirgis Gamil A. , Witkowski Witold A. , Horn Anne , Nielsen Claus J. 
Published: January 2006

AbstractInfrared spectra of 3,3,3‐trifluoropropylsilane (CF3CH2CH2SiH3) and 3,3,3‐trifluoropropylsilane‐d3 (CF3 CH2CH2SiD3) were obtained in the vapour, liquid, and crystalline solid phases in the range 4000–50 cm−1. Additional spectra in argon matrices at 5 K were recorded before and after annealing to temperatures 20–34 K. Raman spectra of the compounds as liquids were recorded at various temperatures between 296 and 183 K and spectra of the amorphous and crystalline solids were obtained.The spectra revealed the existence of two conformers (anti and gauche) in the fluid phases and in the matrices. When the two vapours were shock‐frozen on a cold finger at 78 K, they turned partly crystalline immediately. After subsequent annealing to 140–150 K, ca 7–9 Raman bands of both molecules present in the liquids vanished in the crystal. Similar variations in intensity were observed in the corresponding infrared spectra before and after annealing. The spectra revealed the existence of one conformer (anti) in the crystal.From Raman intensity variations of three independent pairs of anti and gauche bands between 298 and 173 K for the parent compound, and 298 and 183 K for the deuterated analogue, the values ΔconfHo(gauche−anti) = 4.1 ± 0.3 kJ mol−1 for the parent compound and the same value for the deuterated species were obtained in the liquid state. Annealing experiments in the matrices show that the gauche bands vanish after annealing, demonstrating that the anti conformer also has the lower energy here and that the barrier to gauche → anti inter‐conversion is around 5–6 kJ mol−1. The spectra of both conformers have been interpreted in detail.Ab initio and DFT calculations at the HF/6–311G**, B3LYP/6–311 G** and MP2/6–311 G** levels gave optimized geometries, infrared and Raman intensities and vibrational wavenumbers for the anti and gauche conformers. The conformational enthalpy difference derived from the calculations was between 6.0 and 4.1 kJ mol−1 with anti being the low energy conformer. Copyright © 2006 John Wiley & Sons, Ltd.
Experimental and theoretical Raman investigation on interactions of Cu(II) with histamine
Authors: Torreggiani Armida , Esposti Alessandra Degli , Tamba Maurizio , Marconi Giancarlo , Fini Giancarlo 
Published: January 2006

AbstractA vibrational study of histamine (Hm), a small imidazole‐containing hormone involved in many biological processes, and its complexes with copper (II) was carried out at pH 9. Both the Raman and IR spectra present marker bands yielding information on the metal coordination sites of Hm and, as a consequence, on the main species existing in the system.At basic pH Hm gives rise to two predominant complexes: a water‐insoluble polymeric species, [CuLH−1]n, and a monomer, [CuL] or [CuL2]. In the first the imidazole ring takes part in the Cu(II) coordination in a fully deprotonated form, whereas in the second the ring is in the tautomeric I form. In addition, the neutral aminic group participates in the Cu(II) chelation in both species, whereas some ClO4− ions complete the coordination number of Cu(II) to six only in the monomeric complex, probably by replacing H2O or OH− in the coordination sphere.Finally, the Raman spectra were satisfactorily simulated with the aid of the results of theoretical calculations based on the Density Functional Theory, allowing a reliable prediction of the bands of the species supposed to exist in the system. Copyright © 2006 John Wiley & Sons, Ltd.
Dispersion‐compensated supercontinuum generation for ultrabroadband multiplex coherent anti‐Stokes Raman scattering spectroscopy
Authors: Kano Hideaki , Hamaguchi Hiro‐o 
Published: January 2006

AbstractWe have generated a dispersion‐compensated picosecond ultrabroadband supercontinuum light source at the sample position without using any additional compensator such as a prism pair or a grating pair. The dispersion‐compensated supercontinuum, which is obtained just by optimizing the length of a photonic crystal fiber, has been used as a Stokes laser source for ultrabroadband multiplex coherent anti‐Stokes Raman scattering (CARS) spectroscopy. Owing to an optimized temporal overlap between the narrowband pump and the Stokes supercontinuum pulses, a CARS signal has been obtained efficiently with a spectral coverage of more than 2800 cm−1. Furthermore, a vibrationally resonant CARS signal is observed not only when the pump pulse and the Stokes supercontinuum are temporally overlapped but also when the pump pulse follows the supercontinuum. It can be explained by an impulsive excitation of the vibrational coherence by the supercontinuum and a subsequent probe by a narrowband pump pulse. Using the dispersion‐compensated supercontinuum, we can perform not only the frequency‐domain multiplex CARS but also the time‐domain impulsive CARS measurement by controlling the delay time between the narrowband laser and the supercontinuum. Both these techniques can be applied to microspectroscopy in order to obtain the wide spectral range of vibrational resonances and the suppression of the nonresonant background. Copyright © 2006 John Wiley & Sons, Ltd.
Investigation of the low‐spin to high‐spin transition in a novel [Fe(pmea)(NCS)2] complex by IR and Raman spectroscopy and DFT calculations
Authors: Brehm Georg , Reiher Markus , Le Guennic Boris , Leibold Michael , Schindler Siegfried , Heinemann Frank W. , Schneider Siegfried 
Published: January 2006

AbstractThe X‐ray structures of the novel spin crossover complex [Fe(pmea)(NCS)2] with pmea = (bis[(2‐pyridyl)methyl]‐2‐(2‐pyridyl)ethylamin) were determined in its low‐spin (singlet, LS) and high‐spin state (quintet, HS) and compared with the optimized geometries produced by BP86 calculations. IR and Raman (λex = 514.5, 785 and 1064 nm) spectra were recorded at different temperatures between T = 298 K and T = 30 K. Most of the experimentally observed bands could be assigned unambiguously and discussed by comparison with the normal modes calculated for both spin states.The detailed analysis of the temperature dependence of the band contours of specific modes provides strong evidence that significant changes of the inter‐molecular distances occur for all molecules when a certain fraction of the individual molecules has undergone the low‐spin (LS) to high‐spin (HS) transition.The partition function for intra‐molecular vibrations was calculated for both spin states by considering all vibrational wavenumbers that were calculated. The vibration‐related entropy change connected with the LS to HS transition is determined via well‐established thermodynamic relations. For the title compound we found ΔSvib ≈ 40.3 J/(mol·K), which is about twice that determined for [Fe(phen)2(NCS)2]. Consequently, the sum of the purely electronic contribution (∼13.4 J/(mol·K)) and that of the intra‐molecular vibrations equals the average entropic driving force determined for a series of spin‐crossover complexes (∼50 J/(mol·K)). It is therefore most interesting to experimentally determine the entropy change for the complex investigated here and to find out whether this complex exhibits an unusually large entropy change upon the LS to HS transition. Copyright © 2006 John Wiley & Sons, Ltd.
Degenerate and two‐color resonant four‐wave mixing applied to the rotational characterization of high‐lying vibrational states of formaldehyde (Ã, 1A2)
Authors: Tulej M. , Meisinger M. , Knopp G. , Walser A. M. , Beaud P. , Gerber T. , Radi P. P. 
Published: January 2006

AbstractDegenerate and two‐color resonant four‐wave mixing techniques (DFWM and TC‐RFWM) are applied to determine rotational constants of high‐lying vibrational levels in the first excited singlet state Ã(1A2) of formaldehyde. It has been demonstrated that the sensitivity of the spectroscopic technique is applicable to the low‐density environment of a supersonic molecular beam and to predissociating transitions displaying low fluorescence quantum yield. In addition, we take advantage of the superior selectivity of the double‐resonance method, TC‐RFWM, to isolate and assign transitions in the congested region of the (one‐color) DFWM spectra. The line positions of 25 well‐isolated transitions are determined in the $2_{0}^{2}5_{0}^{1}$ band and yield the rotational constants A, B, C and the origin νe. The accuracy of the constants is determined by performing the same procedure for the $2_{0}^{2}4_{0}^{1}$ band where literature data is available for comparison. Copyright © 2006 John Wiley & Sons, Ltd.
Quantitative polarization‐sensitive resonance CARS and resonance Raman spectroscopy on octaethylporphine
Authors: Koster J. , Popp J. , Schlücker S. 
Published: January 2006

AbstractWe present polarization‐sensitive (PS) multiplex coherent anti‐Stokes Raman scattering (CARS) spectra of octaethylporphine (OEP) in solution employing Q band resonance conditions. Several advantages of this four‐wave mixing technique compared with spontaneous resonance Raman (RR) spectroscopy are demonstrated. PS CARS spectroscopy allows the acquisition of high‐quality polarized vibrational spectra of this luminescent D2h symmetric free‐base porphyrin. From a quantitative CARS lineshape analysis, a set of accurate band parameters for the normal modes in the range 1510–1670 cm−1 is determined; in particular, individual spectral contributions from the nearly degenerate modes ν19 and ν2 can be differentiated and unambiguously assigned. The observed difference of π between the coherent phases of totally symmetric ag modes (ν11, ν2, ν10) and non totally symmetric b1g modes (ν19) confirms a correlation with normal mode symmetry. Using the CARS lineshape parameters, hypothetical polarized RR spectra for Q band excitation are generated: this enables a direct comparison with experimentally detected polarized RR spectra obtained with preresonant B band excitation. Major changes in spectral parameters such as intensity enhancements and depolarization ratios of prominent macrocycle modes due to the different electronic resonance conditions are discussed. Copyright © 2006 John Wiley & Sons, Ltd.
Protein secondary structure from deep‐UV resonance Raman spectroscopy
Authors: Huang Cheng‐Yen , Balakrishnan Gurusamy , Spiro Thomas G. 
Published: January 2006

AbstractRaman spectra of proteins that are obtained with deep ultraviolet excitation contain resonance‐enhanced amide bands of the polypeptide backbone, as well as aromatic side chain bands. The amide bands are sensitive to conformation, and can be used to estimate the backbone secondary structure. UV Raman spectra are reported at 206.5 and 197 nm, for a set of 12 proteins with varied secondary structure content, and are used to establish quantitative signatures of secondary structure via least‐squares fitting. Amide band enhancement is greater at 197 nm, where basis spectra are established for β‐turn, as well as α‐helix, β‐sheet and unordered structures; the lower signal strength at 206.5 nm does not provide a reliable spectrum for the first of these. Application of these basis spectra is illustrated for the melting of apo‐myoglobin. The amide band positions and cross sections are discussed. Copyright © 2006 John Wiley & Sons, Ltd.
Ground state vibrational wave‐packet and recovery dynamics studied by time‐resolved CARS and pump‐CARS spectroscopy
Authors: Siebert T. , Schmitt M. , Gräfe S. , Engel Volker 
Published: January 2006

AbstractRecent experiments on gaseous iodine and β‐carotene are analyzed within a wave‐packet description of femtosecond‐time resolved four‐wave mixing spectroscopy. Employing the same formalism, two different experimental setups, both established in the Kiefer group, are treated. In a transient four‐wave‐mixing (FWM) experiment, where two pulses interact simultaneously with the system, the interaction with a third time‐delayed pulse leads to light emission reflecting ground state vibrational dynamics in I2. On the other hand, delaying a FWM‐pulse sequence with respect to a single pump pulse interacting with β‐carotene yields a signal that is directly proportional to the population of a selected nuclear eigenstate in the electronic ground state. Thus, within this setup, it is possible to monitor ground‐state re‐population dynamics mode specifically. Copyright © 2006 John Wiley & Sons, Ltd.
Resonance Raman assignment of myeloperoxidase and the selected mutants Asp94Val and Met243Thr. Effect of the heme distortion
Authors: Brogioni Silvia , Feis Alessandro , Marzocchi Mario P. , Zederbauer Martina , Furtmüller Paul G. , Obinger Christian , Smulevich Giulietta 
Published: January 2006

AbstractResonance Raman (RR) spectra have been acquired for human myeloperoxidase (MPO), and its Met243Thr and Asp94Val mutants with different excitation wavelengths and in polarized light. The proteins were characterized as ferric, ferrous and ferric–CN complexes in order to study the heme configuration in various coordination, spin and oxidation states. Well‐defined spectra of the five‐coordinate high spin (ferrous), six‐coordinate high spin (ferric) and low spin (ferric–CN) species were obtained. The data allowed us to propose an almost complete assignment of the RR bands. The richness of the RR spectra of MPO is because of the activation of almost all the in‐plane skeletal modes observed for the Ni–octaethylporphyrin model compound, induced by the distortion of the heme imposed by the covalent links with the protein. The two mutants, which lost at least one of the covalent links between the protein and the heme group, were useful to determine the effect of the symmetry lowering of the heme group. Copyright © 2006 John Wiley & Sons, Ltd.