bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ciliary neurotrophic factor immunoreactivity is not associated with reactive astrocytes in the rat spinal cord following unilateral spinal nerve ligation
Authors: Madiai Francesca , Goettl Virginia M. , Stephens Robert L. , Hackshaw Kevin V. 
Published: June 2004

AbstractFollowing a direct insult to the central nervous system, ciliary neurotrophic factor (CNTF) is induced in reactive astrocytes adjacent to the injury, where it participates in functional recovery. On the other hand, the role of CNTF in spinal cord plasticity after peripheral nerve injury is unclear. Hence, CNTF immunoreactivity (IR) was evaluated in rat spinal cords following unilateral spinal nerve ligation. CNTF‐IR was found in GFAP‐negative white matter cells exhibiting oligodendrocyte‐like morphology. While GFAP labeling was increased in spinal cords of ligated animals, CNTF‐IR was unchanged, suggesting that CNTF does not regulate spinal astrocyte reactivity generated by peripheral nerve ligation.
Paraoxonase 2 (PON2) polymorphisms and Parkinson's disease
Authors: Costa Lucio G. , Kelada Samir N. , Costa‐Mallen Paola , Farin Fred M. , Viernes Hannah A. , Weller Terri Smith , Franklin Gary M. , Longstreth William T. , Swanson Philip D. , Checkoway Harvey , Furlong Clement E. 
Published: June 2004

AbstractOxidative stress may contribute to the pathogenesis of Parkinson's disease (PD). Paraoxonase 2 (PON2) is an ubiquitously expressed protein which displays antioxidant properties, though it does not have paraoxonase or arylesterase activity like other members of the PON gene family, such as PON1. Two coding region polymorphisms (Cys311Ser and Ala14Gly) of the PON2 gene were investigated by a newly developed method in a population‐based case‐control study of 179 PD patients and 293 controls. No statistically significant differences were found in the distribution of the wild type and mutant alleles between controls and PD. Similarly, no interactions between PON2 and two PON1 polymorphisms (192 and –108) were found. Polymorphisms of PON2 do not appear to be a risk factor for PD.
Spiking activity of neurons in the pigeon nucleus rotundus in slice preparations
Authors: Li Da‐Peng , Tang Zong‐Xiang , Wang Shu‐Rong 
Published: June 2004

AbstractThe thalamic nucleus rotundus in birds relays visual information from the mesencephalic tectum to the telencephalic ecostriatum. The present study examined the firing behaviors of rotundal cells in response to depolarizing current injections in pugeon's brain slices. Eighty‐five cells examined could be classified into five types according to their firing patterns. Type I cells (58.8%) evoked a spike, bursts or regular spiking depending on current intensity. Type II cells (14.1%) produced a hump‐like depolarization that gave rise to a single spike at higher intensity. Type III cells (15.3%) fired a spike or burst only at the onset of current injections. Type IV cells (8.3%) accelerated regular spiking as current intensity increased. Type V cells (3.5%) produced spontaneous spikes that were eliminated by current at higher intensity. The spiking patterns seem to be not correlated to the recording sites. Thirteen neurobiotin‐stained cells are multipolar neurons whose morphology is not related to firing patterns. The functional significance of these firing patterns is discussed.
A stereological study of the tuberomammillary nucleus in the Wistar rat: Morphological and functional comparison among subgroups E1‐E2‐E3
Authors: Rubio S. , Begega A. , Santín L.J. , Miranda R. , Arias J.L. 
Published: June 2004

AbstractIn the present study, we have calculated the total neuronal number and volume of the tuberomammillary nucleus and of each of its subgroups E1, E2 and E3 in the Wistar rat. This estimation was done using stereological methods that can produce accurate quantifications. Neuronal number was estimated by applying the optical fractionator and the total volume of the nucleus by Cavalieri's method. Simultaneously, we quantified the argyrophilic nucleolar organizer regions (Ag‐NORs) of the neurons from these subgroups. The number and area of the Ag‐NORs stained with the silver nitrate technique, reflect the protein synthesis activity of these neurons.Our results show that the tuberomammillary nucleus has a unilateral total neuronal number of 2,460 neurons and a unilateral volume of 0.08756 mm3. We also find statistically significant differences on a morphological level among the different subgroups of the tuberomammillary nucleus. Hence, E2 has the largest number of neurons followed by E3 whereas E1 is the subgroup with the smallest neuronal density. There were no significant differences in the functional parameters: area of neuronal nucleus and mean area and number of Ag‐NOR, among the groups.
Postponed effect of cholecystokinin fragments 30–33 (CCK‐4), and 31–33 (CCK‐3), on albino rats behavior
Authors: Ashmarin I. P. , Rud'ko O. I. , Danilova R. A. , Andreeva L. A. 
Published: June 2004

AbstractIt is generally accepted that regulatory olygopeptides cause short‐term physiological effects. However we demonstrate that CCK‐4, and its shorter fragment CCK‐3 evoke significant long‐term changes in albino rat behavior. The anxiogenic action of CCK‐4 (400 mg/kg) and CCK‐3 (10 mg/kg) was measured by cross‐maze and dark‐light test. The tendency of rats to developing of depression‐like states was evaluated by the Porsolt‐test. In this study both CCK‐4 and CCK‐3 induced significant behavior effects from 40th min to 12th day after the intraperitoneal administration. It was found also that there were significant changes in the level of bioamines and their derivatives not only during the first hours after the administration but also on the 5th and 12th day. The half‐life of these peptides is less than 15 min, so it's possible the induction of some chain‐reactions similar to memory consolidation process.
Design of a poly(L‐histidine)‐carbohydrate conjugate for a new pH‐sensitive drug carrier
Authors: Asayama Shoichiro , Kawakami Hiroyoshi , Nagaoka Shoji 
Published: June 2004

AbstractA poly(L‐histidine) (PLH)‐carbohydrate conjugate has been synthesized as a new macromolecule extracting pH‐dependent properties of PLH with imidazole groups. Because of poor water solubility at physiological pH, the application of PLH with a pKa around 6.0 has been limited in spite of the native possession of the pH‐dependent property change at endosomal pH. Although the PLH modified with aliphatic primary amino groups suddenly precipitated out of the aqueous medium above pH 6.0 as a result of the deprotonation of the imidazole groups, the water solubility of PLH was improved at physiological pH by the conjugation of the aminated PLH with hydrophilic maltopentaose. The resulting PLH‐maltopentaose conjugates and metalloporphyrins formed the complexes which varied their assembling structure below pH 6.0. The PLH‐maltopentaose would be the fundamental compound for designing various drug carriers with the pH sensitivity at endosomal pH. Copyright © 2004 John Wiley & Sons, Ltd.
Micropatterned agarose gels for stamping arrays of proteins and gradients of proteins
Authors: Mayer Michael , Yang Jerry , Gitlin Irina , Gracias David H. , Whitesides George M. 
Published: June 2004

AbstractWe describe a method for repetitive and rapid formation of planar microarrays and gradients of proteins using patterned agarose stamps. It demonstrates: (i) micropatterning of agarose gels with feature sizes as small as 2 μm; (ii) inking of posts (diameter 50–1000 μm) on patterned agarose stamps with one or multiple (here, eight) proteins and repetitive stamping of patterns (>100 times in the case of one protein) and arrays (20 times in the case of eight proteins) without the need for intermediate re‐inking; (iii) transferring spots of proteins with good homogeneity in surface coverage to glass slides; (iv) applying this technique to surface‐based immunoassays; (v) stamping that requires only sub‐nanomolar amounts of protein (typically ∼3 μg in ∼0.6 μL of solution); (vi) stamping without the need for drying of the proteins, as opposed to stamping with stamps made of poly(dimethylsiloxane); and (vii) patterning gradients of proteins by allowing two proteins to diffuse toward each other in an agarose stamp, followed by printing the protein gradients onto a surface.
Comprehensive proteome analysis of ovarian cancers using liquid phase separation, mass mapping and tandem mass spectrometry: A strategy for identification of candidate cancer biomarkers
Authors: Wang Haixing , Kachman Maureen T. , Schwartz Donald R. , Cho Kathleen R. , Lubman David M. 
Published: June 2004

AbstractA two‐dimensional (2‐D) liquid phase separation method, liquid isoelectric focusing followed by nonporous reversed‐phase high performance liquid chromatography (HPLC), was used to separate proteins from human ovarian epithelial whole cell lysates. HPLC eluent was interfaced on‐line to an electrospray ionization (ESI) time of flight (TOF) mass spectrometer to obtain accurate intact protein molecular weights (Mr). 2‐D protein expression maps were generated displaying protein isoelectric point (pI) versus intact protein Mr . Resulting 2‐D images effectively displayed quantitative differential protein expression in ovarian cancer cells versus non‐neoplastic ovarian epithelial cells. Protein peak fractions were collected from the HPLC eluent, enzymatically digested, and analyzed by matrix‐assisted laser desorption/ionization (MALDI) TOF‐mass spectrometry (MS) peptide mass fingerprinting and by MALDI‐quadrupole TOF tandem mass spectrometry peptide sequencing. Interlysate comparisons of differential protein expression between two ovarian adenocarcinoma cell lines, ES2 and MDAH‐2774, and ovarian surface epithelial cells was performed. Five pI fractions from each sample were selected for comparative study and over 300 unique proteins were positively identified from the 2‐D liquid expression maps using MS, which covered around 60% of proteins detected by on‐line ESI‐TOF‐MS. This represents one of the most comprehensive proteomic analyses of ovarian cancer samples to date. Protein bands with significant up‐ or down‐regulation in one cell line versus another as viewed in the 2‐D expression maps were identified. This strategy may prove useful in identifying novel ovarian cancer marker proteins.
Determination of protein‐protein interactions through aldehyde‐dextran intermolecular cross‐linking
Authors: Fuentes Manuel , Segura Rosa L. , Abian Olga , Betancor Lorena , Hidalgo Aurelio , Mateo Cesar , Fernandez‐Lafuente Roberto , Guisan Jose M. 
Published: June 2004

AbstractA very simple strategy, based on the intermolecular cross‐linking of associated proteins by using aldehyde‐dextrans, has been proposed to detect protein‐protein interactions. Aldehyde‐dextran was able to cross‐link different enzymes composed of several polypeptide chains (e.g., trypsin and penicillin G acylase), proteolyzated proteins (e.g., extracts from porcine pancreas) and finally, an immunocomplex (horseradish peroxidase/anti‐horseradish peroxidase). This cross‐linked immunocomplex could be selectively adsorbed on immobilized anti‐rabbit IgG. The presence of unspecific covalent attachment between unrelated protein molecules was not detected. Thus, this strategy permits the cross‐linking of different protein components and avoids the formation of nonspecific protein‐protein associations.
Mitochondrial proteome: Cancer‐altered metabolism associated with cytochrome c oxidase subunit level variation
Authors: Krieg René C. , Knuechel Ruth , Schiffmann Elliot , Liotta Lance A. , Petricoin Emanuel F. , Herrmann Paul C. 
Published: June 2004

AbstractShifts in metabolism associated with tumorigenesis were first noted by Otto Warburg in the 1920s. In the ensuing decades many examples of the phenomenon have been elucidated while the underlying molecular mechanism has remained elusive. As the enzyme complex at the crux of oxidative phosphorylation, cytochrome c oxidase is uniquely positioned to have a very high impact on cellular metabolism. In this study, we test the hypothesis that there is a specific association between altered cytochrome c oxidase subunit levels and altered metabolism by combining the technique of reverse‐phase protein microarray with radiolabeled glucose metabolic studies. Such a relationship is observed with five different cell lines, two of which (1542N and 1542T) are a matched set of normal and tumor‐based lineages derived from the same prostate gland. By measuring the [14C]carbon dioxide production of a cell line metabolizing [1‐14C]glucose and comparing those measurements to values obtained for the same cell line metabolizing [6‐14C]glucose, we determined the relative utilization of the hexose monophosphate shunt and glycolysis progressing through the Krebs cycle metabolic pathway in each cell line. In all cases there is an increased utilization of hexose monophosphate shunt relative to glycolysis progressing through the Krebs cycle in tumor derived relative to normal derived cell lines. Additionally, there is an associated increase in the ratio of nuclear encoded cytochrome c oxidase subunits to mitochondrially encoded cytochrome c oxidase subunits in the tumor‐derived cell lines. These results demonstrate an alteration in subunit levels of a single enzyme complex (cytochrome c oxidase) commensurate with tumor‐altered metabolism.
Ortho effects and cross interaction correlations for the mechanisms of cholesterol esterase inhibition by aryl carbamates
Authors: Lin Gialih , Liu Yu‐Chen , Wu Yon‐Gi , Lee Yu‐Ru 
Published: June 2004

AbstractOrtho‐substituted phenyl‐N‐butyl carbamates (1–11) were synthesized to evaluate the inhibition mechanisms of porcine pancreatic cholesterol esterase. All carbamate inhibitors act as the active site‐directed pseudo substrate inhibitors of the enzymes. The logarithms of dissociation constant (Ki), carbamylation constant (k2) and bimolecular inhibition constant (ki) multiply linearly correlate with the Hammett substituent constant (σ), the Taft–Kutter–Hansch ortho steric constant (ES), and the Swan–Lupton–Hansch ortho polar constant (F). For the –log Ki, log k2 and log ki correlations, the reaction constant for ordinary polar effect (ρ), the intensity factor to ortho steric constant (δ) and the intensity factor to ortho polar constant (f) are 0.7, −0.07, and 0.5; 0.5, 0.04 and −0.5; and 1.1, −0.03 and 0.0, respectively. The cross interaction reaction constant (ρXR) for the –log ki–, log k2– and log ki‐‐σ–ασ*–ασσ* correlations are 3, −2, and 1, respectively. The Ki step may be composed of the following two steps: (1) protonation of carbamates 1–11 and (2) the pseudo‐trans to pseudo‐cis conformation change of protonated carbamates 1–11 due to a large ρXR value of 3 and formation of the enzyme‐protonated carbamates 1–11 tetrahedral intermediate. The k2 step involves departure of the leaving group, which is protonated by the active site histidine of the enzyme, from the tetrahedral intermediate to solution and formation of the carbamyl enzyme. Moreover, the distances between the carbamate and phenyl groups in all transition states of inhibition reactions are relatively short owing to large |ρXR| values. The Ki step shows little ortho steric enhancement effect; moreover, the k2 step shows little ortho steric inhibition effect. Copyright © 2004 John Wiley & Sons, Ltd.
The γ‐ and the δ‐effects in 13C NMR spectroscopy in terms of nuclear chemical shielding (NCS) analysis
Authors: Kleinpeter Erich , Seidl Peter R. 
Published: June 2004

AbstractCarbon‐13 NMR is widely used in the determination of the stereochemistry of organic compounds. Changes in chemical shifts caused by interactions of groups that are close in space normally result in shielding of the carbon and deshielding of the hydrogen nuclei that are involved. This is not always the case, however, and further work on the origin of these effects would be desirable. Early applications of theoretical methods to the study of NMR shielding parameters were not particularly successful, but in recent years, the calculation of NMR shielding parameters by theoretical methods has developed into a useful and popular tool for structural studies by NMR. A promising approach to the problem of distinguishing and evaluating stereochemical influences on carbon and hydrogen chemical shifts is provided by natural chemical shielding (NCS) analysis. This method allows a partitioning of theoretical NMR shieldings into magnetic contributions from bonds and lone pairs of the molecule using the natural bond orbital (NBO) method. In order to investigate the origins of steric effects, we employed the NCS analysis to axial/equatorial‐Me‐cyclohexane, norbornane and exo/endo‐Me‐norbornane, in addition to n‐pentane in the anti, gauche and gP gM conformations. Our results indicate that distortions in molecular structure due to steric effects can result in bond stretching or compression or in angular distortions. Changes in bond lengths result in the predictable shielding or deshielding of the nuclei that are involved. Where the molecular framework may be distorted to alleviate strain, chemical shifts appear to reflect changes in angles. Copyright © 2004 John Wiley & Sons, Ltd.
Steric inhibition of resonance: revision of the principle on the electronic spectra of methyl‐substituted acetophenones
Authors: Kulhánek Jirií , Böhm Stanislav , Palát Karel , Exner Otto 
Published: June 2004

AbstractThe principle of steric hindrance to resonance (SIR) was revised on the well‐known example of the electronic spectra of methyl‐substituted acetophenones. The spectra were reinvestigated on an extended series 1–14, and computer separation of bands was undertaken. The conformation of these molecules, total energy, rotational barrier, geometry of the transition state and electronic spectra were calculated within the framework of the density functional theory. The classical literature was correct that some molecules of the series are twisted from the planar arrangement by a variable angle ϕ. However, these angles do not agree with the values anticipated; the main difference is that all derivatives with only one ortho‐methyl group are planar (ϕ = 0). Our main objection is that the rotational barrier is in some cases very low; hence ϕ does not have the same importance with all derivatives. A better measure of steric hindrance is the calculated energy Δ4E of the isodesmic reaction Eqn (4), in which the molecule of the substituted acetophenone is formed from acetophenone and a methyl‐substituted benzene. In contrast to the angles ϕ, there was good agreement between calculation and experiment in electronic spectra, viz. between the extinction coefficients of the 1La band and the calculated oscillator strengths, at least in the relative values. Summarizing, SIR is valid as a qualitative principle but the reported angles ϕ based on several experimental quantities are often wrong. Each case must be examined separately as to the actual shape of the molecule. The classical paper by Braude et al. is a particularly bad example: the basic hypothesis of a planar excited state was not confirmed by our calculations. Copyright © 2004 John Wiley & Sons, Ltd.
Intensely fluorescent dipyrrinones
Authors: Boiadjiev Stefan E. , Lightner David A. 
Published: June 2004

AbstractIntense fluorescence from a new, more highly conjugated (benzannelated) xanthoglow analog, 9,11‐ dimethyl‐10‐[2‐(methoxycarbonyl)ethyl]‐5H,7H‐pyrrolo[2′,1′:6,1]pyrimidino[3,4‐a]isoindole‐5,7‐dione (1), was determined accurately and compared with fluorescence from the parent xanthoglow, 1‐ethyl‐8‐[2‐(methoxycarbonyl) ethyl]‐2,7,9‐trimethyl‐3H,5H‐dipyrrolo[1,2‐c:2′,1′‐f]pyrimidine‐3,5‐dione (2). Benzoxanthoglow (1) gave a quantum yield for fluorescence (ϕF) of 0.78 in cyclohexane (λexc 412 nm, λem 487 nm), whereas xanthoglow methyl ester (2) gave ϕF = 0.80 in cyclohexane (λexc 410 nm, λem 473 nm). In DMSO, 1 gave ϕF = 0.55 (λexc 419 nm, λem 530 nm) and 2 gave ϕF = 0.65 (λexc 419 nm, λem 508 nm), illustrating the large Stokes shifts and strong fluorescence properties of these easily synthesized yellow pigments. Copyright © 2004 John Wiley & Sons, Ltd.
Solvolysis of aromatic benzoyl chlorides: how is the π‐electron stabilization of the aromatic acyl chlorides and acylium cations related to the π‐electron delocalization?
Authors: Krygowski Tadeusz M. , Cyrański Michal K. , Sung Dae D. , Stepień Beata T. 
Published: June 2004

AbstractHomodesmotic stabilization energies of XPhCOCl and XPhCO+ estimated at the B3LYP/6–311G** level of theory for eight para‐substituted derivatives (X = H, Cl, F, OH, OCH3, NH2, NO2 and CH3) are good descriptors for changes of the π‐electron delocalization parameters of the ring, measured by NICS and HOMA, and also for geometry parameters of COCl and CO+ groups. Good correlations are also found for atomic charges in these groups. Electron‐donating substituents elongate the C—Cl bond dramatically and increase the negative charge at the Cl atom in the XPhCOCl molecule. Copyright © 2004 John Wiley & Sons, Ltd.
298 K enthalpies of formation of monofluorinated alkanes: theoretical predictions for methyl, ethyl, isopropyl and tert‐butyl fluoride
Authors: Kormos Bethany L. , Liebman Joel F. , Cramer Christopher J. 
Published: June 2004

AbstractExperimentally measured 298 K enthalpies of formation are not well established for monofluoroalkanes. To supplement available experimental data, the multi‐coefficient G3 (MCG3) quantum mechanical model has been applied to estimate this thermochemical quantity for methyl fluoride, ethyl fluoride, 2‐fluoropropane (isopropyl fluoride) and 2‐fluoro‐2‐methylpropane (tert‐butyl fluoride). The following 298 K standard enthalpies of formation are suggested for these monofluoroalkanes: ΔH (MeF) = −57.1 ± 0.2 kcal mol−1, ΔH (EtF) = −66.5 ±  0.4 kcal mol−1, ΔH (i‐PrF) = −75.4± 0.5 kcal mol−1, and ΔH (t‐BuF) = −86.0 ± 2.0 kcal mol−1 (1 kcal =  4.184 kJ). Copyright © 2004 John Wiley & Sons, Ltd.