bluuebunny/crossref_metadata_2025_split huggingface dataset:
Brain aromatase is neuroprotective
Authors: Azcoitia Iñigo , Sierra Amanda , Veiga Sergio , Honda Shin‐ichiro , Harada Nobuhiro , Garcia‐Segura Luis M. 
Published: September 2002

AbstractThe expression of aromatase, the enzyme that catalyzes the biosynthesis of estrogens from precursor androgens, is increased in the brain after injury, suggesting that aromatase may be involved in neuroprotection. In the present study, the effect of inactivating aromatase has been assessed in a model of neurodegeneration induced by the systemic administration of neurotoxins. Domoic acid, at a dose that is not neurotoxic in intact male mice, induced significant neuronal loss in the hilus of the hippocampal formation of mice with reduced levels of aromatase substrates as a result of gonadectomy. Furthermore, the aromatase substrate testosterone, as well as its metabolite estradiol, the product of aromatase, were able to protect hilar neurons from domoic acid. In contrast, dihydrotestosterone, the 5α‐reduced metabolite of testosterone and a nonaromatizable androgen, was not. These findings suggest that aromatization of testosterone to estradiol may be involved in the neuroprotective action of testosterone in this experimental model. In addition, aromatase knock‐out mice showed significant neuronal loss after injection of a low dose of domoic acid, while control littermates did not, indicating that aromatase deficiency increases the vulnerability of hilar neurons to neurotoxic degeneration. The effect of aromatase on neuroprotection was also tested in male rats treated systemically with the specific aromatase inhibitor fadrozole and injected with kainic acid, a well characterized neurotoxin for hilar neurons in the rat. Fadrozole enhanced the neurodegenerative effect of kainic acid in intact male rats and this effect was counterbalanced by the administration of estradiol. Furthermore, the neuroprotective effect of testosterone against kainic acid in castrated male rats was blocked by fadrozole. These findings suggest that neuroprotection by aromatase is due to the formation of estradiol from its precursor testosterone. Finally, a role for local cerebral aromatase in neuroprotection is indicated by the fact that intracerebral administration of fadrozole enhanced kainic acid induced neurodegeneration in the hippocampus of intact male rats. These findings indicate that aromatase deficiency decreases the threshold for neurodegeneration and that local cerebral aromatase is neuroprotective. Brain aromatase may therefore represent a new target for therapeutic approaches to neurodegenerative diseases. © 2001 John Wiley & Sons, Inc. J Neurobiol 47: 318–329, 2001
Gap junctional coupling between progenitor cells at the retinal margin of adult goldfish
Authors: Tamalu Fuminobu , Chiba Chikafumi , Saito Takehiko 
Published: September 2002

AbstractWe prepared living slice preparations of the peripheral retina of adult goldfish to examine electrical membrane properties of progenitor cells at the retinal margin. Cells were voltage‐clamped near resting potential and then stepped to either hyperpolarizing or depolarizing test potentials using whole‐cell voltage‐clamp recordings. Electrophysiologically examined cells were morphologically identified by injecting both Lucifer Yellow (LY) and biocytin. All progenitor cells examined (n = 37) showed a large amount of passively flowing currents of either sign under suppression of the nonjunctional currents flowing through K+ and Ca2+ channels in the cell membrane. They did not exhibit any voltage‐gated Na+ currents. Cells identified by LY fills were typically slender. As the difference between the test potential and the resting potential increased, 13 out of 37 cells exhibited symmetrically voltage‐ and time‐dependent current decline on either sign at the resting potential. The symmetric current profile suggests that the current may be driven and modulated by the junctional potential difference between the clamping cell and its neighbors. The remaining 24 cells did not exhibit voltage dependency. A gap junction channel blocker, halothane, suppressed the currents. A decrease in extracellular pH reduced coupling currents and its increase enhanced them. Dopamine, cAMP, and retinoic acid did not influence coupling currents. Injection of biocytin into single progenitor cells revealed strong tracer coupling, which was restricted in the marginal region. Immature ganglion cells closely located to the retinal margin exhibited voltage‐gated Na+ currents. They did not reveal apparent tracer coupling. These results demonstrate that the marginal progenitor cells couple with each other via gap junctions, and communicate biochemical molecules, which may subserve or interfere with cellular differentiation. © 2001 John Wiley & Sons, Inc. J Neurobiol 48: 204–214, 2001
Optimal sampling of electrophysiological signals
Authors: Jaw Fu‐Shan 
Published: September 2002

AbstractAction potentials (APs) and field potentials (FPs) are commonly used to study functions of the brain. To facilitate their analysis, computer methods are often used. The high‐speed nature of APs and the large amount of data of FPs put stringent requirements on the sampling rate used. To determine optimal sampling rates for these signals a modified sampling equation is derived. This equation formulates the relationship among the order of the anti‐aliasing filter, the sampling rate, and the number of bits of quantization. For convenience, a table is also provided to reveal the optimal sampling rate for various combinations of filters and analog‐to‐digital converter cards commonly available. The recordings of compound action potentials, APs, and FPs were practically used to further examine this relationship. Under the specified conditions for the recording of these electrophysiological signals, their highest frequency contents are about 10 kHz, 9.3 kHz and 40 Hz, respectively. In conclusion, this paper provides a tutorial, quick reference, and step‐by‐step guide to sample a signal faithfully; that is, free from the contamination of aliasing errors no matter the spectrum of the signal is known. Also, the role of necessity of a high order anti‐aliasing filter is emphasized.
Alteration in glycoconjugate metabolism in CNS disorders ‐ role of isoprenoid pathway
Authors: Kurup Ravi Kumar Achutha , Devi Deepa , Augustine Jyothi , Kurup Parameswara Achutha 
Published: September 2002

AbstractThe isoprenoid pathway which is upregulated in neuropsychiatric disorders produces two metabolites which can regulate glycoconjugate metabolism ‐ dolichol (required for N‐glycosylation) and digoxin (endogenous membrane sodium‐potassium ATPase inhibitor producing magnesium depletion). It is known that Mg++ deficiency can influence glycoconjugate metabolism. The results showed an increase in the concentration of serum total glycosaminoglycan (GAG), glycolipids and carbohydrate component of glycoproteins and a decrease in the total GAG and carbohydrate component of glycoproteins in the Red blood cell (RBC) membrane suggesting their reduced incorporation into the membrane. The pattern of change in individual GAG in the serum was different, however heparan sulphate (HS) and chondroitin sulphate (ChS) increased in most of the disorders studied. The activity of GAG degrading enzymes and glycohydrolases showed significant increase in the serum in all the groups suggesting reduced lysosomal stability consequent to defective lysosomal membrane formation. The importance of altered glycoconjugate metabolism in the pathogenesis of multiple sclerosis, Parkinson's disease, schizophrenia, epilepsy and CNS gliomas is stressed.
Regulation or revenues? An analysis of local business licences, with a case study of the single business permit reform in Kenya
Authors: Devas Nick , Kelly Roy 
Published: September 2002

AbstractLicensing of businesses by local governments is a common practice in many countries. While business licensing has its origins in regulation, it is often seen as little more than a revenue source for local government. This article reviews the potentially conflicting objectives of regulation and revenue generation, and outlines the various forms which local taxation of business has taken in a number of countries. In practice, the regulatory aspects of local business licensing in many developing countries are ineffective at best and counterproductive at worst, and there are pressures to sweep away most local business licences as part of deregulatory reform. Yet local governments in many countries are in dire need of revenue sources in order to finance local service provision. The article analyses the reforms that have been introduced to business licensing in Kenya. There, traditional business licences have been replaced with a Single Business Permit, with the twin objectives of increasing local revenues and reducing regulatory compliance costs on businesses. Initial results suggest that, while there have been some initial start‐up problems, both these objectives are being achieved. Copyright © 2001 John Wiley & Sons, Ltd.
Priority setting in agricultural research: beyond economic surplus methods
Authors: Smith Peter 
Published: September 2002

AbstractThe article examines the issue of priority setting in Third World agricultural research organizations, for those research sectors and topics which—mainly because of the difficulty of quantifying benefits—are outside the domain of economic surplus and benefit/cost techniques. The issue is redefined as one of processing ill‐structured decisions, i.e., decisions in which there is no unique, identifiable, objectively optimal solution. The implications of this for the concept of rational action in this field are explored, and the results used to define a practical approach. This centres on a radical review of the possible options and criteria in priority setting, using four techniques (challenge groups, repertory grid, creativity techniques and flow charting). The final section of the article examines the decision‐making aspects of these techniques in three priority‐setting contexts of increasing difficulty: within a department, where the issue is essentially one of technical choice between competing research lines; within a major institute or research sector, where there is substantial competition for resources; and in an institute or sector which is facing a crisis of resources or relevance. Copyright © 2001 John Wiley & Sons, Ltd.
Deregulation and the Racial Composition of Airlines
Authors: Agesa Jacqueline 
Published: September 2002

AbstractEconomic theory suggests that the enhanced product market competition of deregulation reduces employers' ability to discriminate when hiring. Recent studies of the effect of deregulation on racial employment in the naturally competitive trucking industry find that deregulation increased minority employment. This study examines the effect of deregulation on racial employment in the airline industry. Because deregulation transformed airlines from wasteful service competition to rigorous price competition, deregulation's effect on racial hiring in this continuously competitive industry is not apparent. This study finds that deregulation only modestly changed the racial composition of major airline occupations, which suggests that the change in market structure as a result of deregulation may largely determine the effect of regulatory reform on the racial composition of an industry. © 2001 by the Association for Public Policy Analysis and Management.
Photovoltaics literature survey (No. 8)
Authors: Keevers Mark J. 
Published: September 2002

AbstractIn order to help keep readers up‐to‐date in the field each issue of Progress in Photovoltaics will contain a list of recently published journal articles most relevant to its aims and scope. This list is drawn primarily from recent issues of IEEE Transactions on Electron Devices, Journal of Applied Physics, Progress in Photovoltaics, Solar Energy and Solar Energy Materials and Solar Cells, with additional journals surveyed if space permits. To assist the reader, the list is separated into broad categories, but please note these classifications are by no means strict. Also note that inclusion in the list is not an endorsement of a paper's quality. If you have any suggestions please email Mark Keevers at markk@ psolar.com.au. Copyright © 2001 John Wiley & Sons, Ltd.
Nanoscale calorimetry of isolated polyethylene single crystals
Authors: Kwan A. T. , Efremov M. Yu. , Olson E. A. , Schiettekatte F. , Zhang M. , Geil P. H. , Allen L. H. 
Published: September 2002

AbstractWe used thin‐film differential scanning calorimetry to investigate the melting of isolated polyethylene single crystals with lamellar thicknesses of 12 ± 1 nm. We observed the melting of as few as 25 crystals. Over a wide number of crystals (25–2000 crystals), the heat of fusion was 40% larger than the bulk value. The melting temperature of the isolated single crystals was 123 ± 2 °C, 9 °C lower than that of the bulk material. We also measured the heat of fusion of quenched crystals (±15%) over a wide range of heating rates (20,000–100,000 K/s). Annealing the quenched crystals resulted in shifts in the endotherm peak by as much as 15 °C. © 2001 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 39: 1237–1245, 2001
Phospholipase A2 degradation products modulate epithelial and stromal 5α‐reductase activity of human benign prostatic hyperplasia in vitro
Authors: Weisser Heike , Ziemssen Tjalf , Krieg Michael 
Published: September 2002

AbstractBACKGROUNDRecent studies have demonstrated the inhibition of 5α‐reductase activity in human prostate by phospholipases. Among those phospholipases, phospholipase A2 cleaves one of the acyl chains from phospholipids, thereby producing fatty acids and lysophospholipids such as LPC, LPS, and LPE. Therefore, we were interested in the effect of those lysophospholipids on 5α‐reductase activity in human benign prostatic hyperplasia (BPH).METHODSIn a first set of experiments, cell homogenates were incubated with phospholipase A2 either in the presence or absence of albumin, which is known to bind fatty acids and lysophospholipids. Thereafter, the effect of lysophospholipids of known structure on 5α‐reductase activity was investigated.RESULTSIn epithelium and stroma of human BPH, 5α‐reductase activity was inhibited in a dose‐dependent manner by phospholipase A2. In the presence of albumin, this inhibition was enhanced. In epithelium, LPC at low concentration yielded a dose‐dependent stimulation of 5α‐reductase activity up to 167%. At higher concentrations, epithelial as well as stromal 5α‐reductase activity was inhibited significantly. As indicated by results of enzyme kinetic analyses, the LPC‐mediated activation in the epithelium results from an increase of the active population of 5α‐reductase. In contrast, LPC reduces the affinity of epithelial 5α‐reductase to testosterone. LPE had no effect on epithelial 5α‐reductase, whereas stromal 5α‐reductase was inhibited in a dose‐dependent manner up to 46%. Finally, LPS stimulated epithelial and stromal 5α‐reductase activity; this stimulation was significantly stronger in epithelium (296%) than in stroma (163%). The LPC‐mediated effects could be neutralized by the addition of albumin.CONCLUSIONSThe present data on BPH tissue suggest that lysophospholipids may play a specific and structure‐related role in the posttranslational regulation of human prostatic 5α‐reductase. Prostate 50: 4–14, 2002. © 2002 Wiley‐Liss, Inc.
Differential expression of matrix metalloproteinases and their tissue inhibitors in human primary cultured prostatic cells and malignant prostate cell lines
Authors: Zhang Ju , Jung Klaus , Lein Michael , Kristiansen Glen , Rudolph Birgit , Hauptmann Steffen , Schnorr Dietmar , Loening Stefan A. , Lichtinghagen Ralf 
Published: September 2002

AbstractBACKGROUNDThe aim was to investigate the expression of matrix metalloproteinases (MMPs), membrane type MMPs (MT‐MMPs), and their inhibitors (TIMPs) in human primary cultured prostatic cells and malignant prostate cell lines.METHODSReverse transscription‐polymerase chain reaction‐based measurements of the mRNA levels of MMP‐2, MMP‐7, MT1‐MMP, MT3‐MMP, TIMP‐1, and TIMP‐2 in relation to the house‐keeping gene glyceraldehyde phosphate dehydrogenase were performed in cancerous and non‐cancerous prostatic tissue samples, in primary cell cultures of epithelial cells, in both fibroblasts, and smooth‐muscle cells as stromal cells, and in the human malignant prostatic cell lines DU‐145, LNCaP, and PC‐3.RESULTSMMP‐2 was mainly expressed in the stromal cells and MMP‐7 showed their highest values in the epithelial cells. MT1‐MMP, MT3‐MMP, TIMP‐1, and TIMP‐2 were found both in the stromal and in the epithelial cells, but there were some differences between the expressions in fibroblasts and smooth‐muscle cells. Different expressions were also observed between the cells deriving from the primary cell cultures, the benign cell line BPH‐1, and the malignant cell lines LNCaP, D‐145, and PC‐3.CONCLUSIONSThese exemplary results concerning different expressions of MMPs and TIMPs in cells from prostatic tissue suggest that a better insight into changes observed in prostatic tissue needs studies on cells cultured from the tissue. Prostate 50: 38–45, 2002. © 2002 Wiley‐Liss, Inc.
The action of phosphine against the eggs of phosphine‐resistant and ‐susceptible strains of Rhyzopertha dominica F
Authors: Rajendran Somiahnadar , Nayak Kirti R , Anjum Siddiqha Saba 
Published: September 2002

AbstractThe effect of phosphine at exposure periods of 24, 48 and 120 h on hatching and mortality of 0‐ to 1‐day‐old eggs of susceptible (TN6) and resistant (FC10) strains of Rhyzopertha dominica of field origin was investigated. The fumigant affected hatching in both the strains. In a 48‐h exposure at 27 (± 2) °C, the LD99 doses for the eggs of TN6 and FC10 were 0.56 and 3.25 mg litre−1, respectively. Significant reduction in hatching was observed in treated batches with progressive increase of phosphine dose in the first 2–3 days. On subsequent days the numbers hatching were often similar to those in controls, and sometimes exceeded control hatch, especially following a 5‐day exposure. A critical change in the order of susceptibility of egg and adult stages of the two strains was noticed. In 48‐h exposures, eggs of the susceptible strain were more tolerant than their adults, whilst the reverse was true in the resistant strain.© 2001 Society of Chemical Industry
Amaranthus palmeri resistance and differential tolerance of Amaranthus palmeri and Amaranthus hybridus to ALS‐inhibitor herbicides
Authors: Burgos Nilda R , Kuk Yong‐In , Talbert Ronald E 
Published: September 2002

AbstractSuspected imazaquin‐resistant accessions of Amaranthus palmeri were studied to determine the magnitude of resistance and cross‐resistance to acetolactate synthase (ALS)‐inhibiting herbicides and compare differential tolerance of A palmeri and Amaranthus hybridus to ALS inhibitors. Five of seven A palmeri accessions were resistant to imazaquin. The most imazaquin‐resistant accession, accession 7, also showed 74, 39 and 117 times higher resistance than the susceptible biotype to chlorimuron, diclosulam and pyrithiobac, respectively. Resistance to imazaquin and cross‐resistance to other ALS inhibitors in A palmeri was due to a less‐sensitive ALS enzyme. A palmeri was 70 times more tolerant to imazaquin than A hybridus. A palmeri was also seven times more tolerant to pyrithiobac than A hybridus. Differences in ALS enzyme sensitivity could not fully account for the high tolerance of A palmeri to imazaquin compared to A hybridus. Both species were equally affected by chlorimuron and diclosulam.© 2001 Society of Chemical Industry
Time‐dependent density functional calculations of the Q‐like bands of phenylene‐linked free‐base and zinc porphyrin dimers
Authors: Yamaguchi Yoichi , Yokomichi Yasunori , Yokoyama Shiyoshi , Mashiko Shinro 
Published: September 2002

AbstractTime‐dependent density functional theory (TDDFT) calculations have been performed on the excitation energies and oscillator strengths of the Q‐like bands of three structural isomers of phenylene‐linked free‐base (FBP) and zinc (ZnP) porphyrin dimers. The TDDFT calculated results on the low‐lying excited states of the reference monomers, FBP and ZnP, are in excellent agreement with previously calculated and experimental results. It is found that the 1,3‐ and 1,4‐phenylene‐linked dimers have monomerlike Q bands that are slightly red‐shifted compared to the monomers and new Q′ bands comprised of the cross‐linked excitations from the FBP (ZnP) ring to the ZnP (FBP) ring at considerably lower energies than the monomer Q bands. For the 1,2‐phenylene‐linked dimer, the direct π–π interaction between porphyrin rings caused by the van der Waals repulsion between them provides strong mixing of the Q′ bands with the Q bands, which causes its minimum excitation energy to be red‐shifted by 0.05 eV compared to the other isomers. The oscillator strengths of the Q′ bands are also unexpectedly found to be as strong as those of the Q bands in the dimers. © 2001 John Wiley & Sons, Inc. Int J Quantum Chem 84: 338–347, 2001
Phase behavior of C60 by computer simulation using ab‐initio interaction potential
Authors: Fartaria Rui P. S. , Silva Fernandes Fernando M. S. , Freitas Filomena F. M. , Rodrigues Pedro C. R. 
Published: September 2002

AbstractA first‐principles intermolecular potential recently proposed by Pacheco and Ramalho [Phys Rev Lett 1997, 79, 3873–3876] has been used with the Gibbs ensemble and Gibbs–Duhem integration Monte Carlo methods to simulate the vapor–liquid and fluid–solid coexistence properties of C60. The critical properties were calculated by fitting the results to the laws of rectilinear diameters and order parameter scaling. The triple‐point properties were determined from the limiting behavior of the Gibbs ensemble vapor–liquid simulations at the lowest temperature range. A stable liquid phase is predicted for temperatures between 1570±20 and 2006±27 K and densities between 0.444±0.003 and 1.05±0.01 nm−3. The estimated critical and triple‐point pressures are, respectively, 35±6 and 5±16 bars. We show for the first time, to our knowledge, that it is possible, strictly by computer simulation, to estimate a triple point for C60 in accordance with the predictions of theoretical methods and the basic concepts of thermodynamics. The liquid and fluid radial distribution functions indicate the presence of solid or glasslike features. This may support the suggestion of a more cooperative interaction of clusters in C60. A comparison of our results with the data obtained by other authors is presented and discussed. © 2001 John Wiley & Sons, Inc. Int J Quantum Chem 84: 375–387, 2001