bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cyclic AMP differentiation of the oligodendroglial cell line N20.1 switches staurosporine‐induced cell death from necrosis to apoptosis
Authors: Studzinski Diane M. , Benjamins Joyce A. 
Published: August 2002

AbstractUnderstanding the regulation of cell death pathways is critical for protecting myelin‐producing cells and their associated axons during injury resulting from multiple sclerosis and other degenerative diseases. The immortalized N20.1 oligodendroglial cell line provides a useful model for identifying mechanisms that can be exploited to attenuate cell death in myelin‐producing cells and their precursors. In our hands, the N20.1 cell line exhibits different characteristics and morphology depending on temperature (permissive or non‐permissive) and the presence of cAMP‐elevating agents (Studzinski et al. [1998] Neurochem. Res. 23:435–441; Boullerne et al. [1999] J. Neurochem. 72:1050–1060; Studzinski et al. [1999] J. Neurosci. Res. 57:633–642). Our laboratory previously observed that NO donors cause primarily necrotic death in N20.1 cells grown at permissive temperature, but the NO donor SNP switched a portion of cell death to the apoptic pathway. We have continued our study of apoptotic death in these cells by comparing the effects of staurosporine, a known apoptotic agent, on cells grown at the permissive temperature (“undifferentiated”) vs. the non‐permissive temperature in the presence of forskolin (“differentiated”). Undifferentiated N20.1 cells exhibit maximal cell death after 24 hr of exposure to 50 nM staurosporine, whereas differentiated cells show delayed cell death, with maximal death seen after 48 hr. Pyknotic nuclei were observed in both growth conditions; however, differentiated cells were protected by caspase inhibitors, whereas undifferentiated cells were not. Increased ssDNA staining and DNA laddering were found following 24‐hr staurosporine treatment in the differentiated cells only. These results support the conclusion that N20.1 cells can switch from necrotic to apoptotic cell death when cell division is slowed and cyclic AMP is elevated. J. Neurosci. Res. 66:691–697, 2001. © 2001 Wiley‐Liss, Inc.
Mitochondrial polarization in rat hippocampal astrocytes is resistant to cytosolic Ca2+ loads
Authors: Kahlert Stefan , Schild Lorenz , Reiser Georg 
Published: August 2002

AbstractThe influence of physiological Ca2+‐inducing stimuli and agents mimicking ischemic conditions on mitochondrial potential was studied in postnatal (P1) hippocampal astrocytes. Cytosolic Ca2+ loads with characteristic kinetics of rise and duration, detected by Fura‐2, were provoked by extracellular Ca2+ influx, release from InsP3‐sensitive intracellular stores, or inhibition of the reloading of endoplasmic reticulum Ca2+ stores. Inhibitors of mitochondrial respiration caused only moderate release of Ca2+ from intracellular stores, inducing a rise of less than 60 nM. The maximal Ca2+ rise was found with InsP3‐mediated responses (500 nM; via ATP) or with ionophore (4‐Br‐A23187)‐mediated Ca2+ influx from extracellular medium (770 nM). Remarkably, all these agents causing significant rise of cytosolic Ca2+, only minimally depolarized the mitochondria. Membrane potential of mitochondria was monitored by Rh123 or TMRE. Depolarization was only found with very high cytosolic Ca2+ levels (above 60 μM; measured by fura FF). These were achieved with external Ca2+ influx by ionophore in combination with inhibition of glycolysis. Thus, mitochondria in the astrocytes are obviously not sensitive to moderate cytosolic Ca2+ loads, irrespective of the source of Ca2+. Furthermore, isolated rat brain mitochondria display a low sensitivity of respiratory activity to Ca2+, which is consistent with the data obtained with the astrocytes in vitro. The capacity of isolated mitochondria to build up a potential was gradually reduced at low micromolar Ca2+ and totally compromised only at Ca2+ concentrations in the 100 μM range. © 2001 Wiley‐Liss, Inc.
Dual mechanisms of Ca2+ increases elicited by N‐methyl‐D‐aspartate in immature and mature cultured cortical neurons
Authors: Nakamichi Noritaka , Ohno Hiroshi , Kuramoto Nobuyuki , Yoneda Yukio 
Published: August 2002

AbstractCortical primary cultures were loaded with the fluorescent indicator fluo‐3 for assessment of intracellular‐free Ca2+ ions with the aid of a confocal laser‐scanning microscope. The addition of N‐methyl‐D‐aspartic acid (NMDA) markedly increased the number of fluorescent cells in a manner sensitive to prevention by both an NMDA channel blocker and MgCl2. In the absence of added MgCl2, NMDA induced a sustained increase in the number of fluorescent cells with a transient increase by KCl in cells cultured for 3 days in vitro (DIV). Both nifedipine and dantrolene were more potent in preventing the increase by NMDA in cortical preparations cultured for 9 DIV than those for 3 DIV. These results suggest that activation of NMDA receptors may lead to a sustained increase in intracellular‐free Ca2+ concentrations in immature cultured neurons, in a manner less dependent on the influx through L‐type voltage‐dependent channels as well as the release from intracellular stores than in mature neurons. © 2001 Wiley‐Liss, Inc.
Modulation of 5‐HT system in mice with a targeted disruption of neuromedin B receptor
Authors: Yamano Mariko , Ogura Hiroo , Okuyama Shigeru , Ohki‐Hamazaki Hiroko 
Published: August 2002

AbstractTo assess the role of neuromedin B receptor (NMB‐R) on the modulation of serotonergic (5‐HT) system, the function of the 5‐HT system was examined in mice lacking the NMB‐R gene. Immunohistochemical analysis of brain sections revealed that 5‐HT expression level in the dorsal raphe neurons was elevated in NMB‐R‐deficient mice compared with wild‐type mice. Although restraint stress enhanced 5‐HT expression in these neurons in wild‐type mice, this treatment did not affect 5‐HT expression level in NMB‐R‐deficient mice, indicating the modulation of 5‐HT system in the mutant mice. Since 5‐HT system is involved in responses to stress and anxiety, we characterized stress response in these mice. The number of c‐Fos expressing cells in the paraventricular nucleus of the hypothalamus was higher in NMB‐R‐deficient mice than in wild‐type mice in both basal and stressed conditions. Moreover, the plasma corticosterone level under restraint stress was elevated in NMB‐R‐deficient mice compared to wild‐type mice. In the forced swimming tests, the duration of immobility was longer in mutant mice than in wild‐type mice. These data show dysregulated response to stress in NMB‐R‐deficient mice. However, behavior related to anxiety, assessed by elevated plus‐maze and light‐dark box, was not affected in NMB‐R‐deficient mice. NMB‐R is known to be expressed in dorsal raphe neurons, and our data suggest that NMB‐R has an important role in fine tuning of subsets of 5‐HT neurons in this nucleus, and impairment of this system leads to the dysregulated response to stress. © 2002 Wiley‐Liss, Inc.
Climate change in the Colorado Rocky Mountains: free air versus surface temperature trends
Authors: Pepin N. , Losleben M. 
Published: August 2002

AbstractA high elevation data set of surface temperatures from the Front Range of the Rocky Mountains in Colorado, USA, is analysed for evidence of long‐term change (1952–98). Sites range from the high plains of Colorado (1509 m) to the alpine tundra (3749 m). Systematic changes in surface‐based lapse rates are uncovered, with absolute cooling at the highest elevations, but little temperature change on the high plains. There is lapse‐rate steepening at the higher elevations (>3000 m). A synoptic analysis using gridded pressure data shows lapse rate changes to be largely independent of synoptic type. Radiosonde ascents from Denver (1956–98) and Grand Junction (1946–98) are used to derive air equivalent temperatures (AETs) at the same elevations as the surface records. AETs show a contrasting temporal trend, with absolute warming at all levels. Furthermore, free‐air lapse rates are weakening at higher elevations, the warming becoming stronger with height. A comparison of the two data sets through derivation of free‐air–surface temperature differences shows that the alpine tundra zone of the high Rockies is becoming a progressively stronger heat sink. Possible explanations include increased snow cover, enhanced air movement over the surface and decreased solar radiation input. The heat sink enhancement has led to rapid cooling in the alpine tundra that could not be predicted from the free‐air record, casting doubt upon the strong dependence on free‐air temperature changes in climate modelling when investigating the potential effects of global warming in mountainous regions. In addition, these local surface trends are of the opposite sign to global and other regional trends identified in many recent observational and modelling studies. Copyright © 2002 Royal Meteorological Society.
Hard‐to‐cook tendency of chickpea (Cicer arietinum L) varieties
Authors: Reyes‐Moreno C , Rouzaud‐Sandez O , Milán‐Carrillo J , Garzón‐Tiznado J A , Camacho‐Hernández L 
Published: August 2002

AbstractChickpeas (Cicer arietinum L) develop the hard‐to‐cook (HTC) defect during storage at high temperatures (>25 °C) and high relative humidities (RH>65%). The objective of this work was to assess the tendency of chickpea varieties to become HTC. Three samples of chickpeas (Surutato 77, Mocorito 88 and Blanco Sinaloa 92) were grown under irrigation conditions. Two hardening procedures were used: (1) storage hardening—samples were stored at 33–35 °C and 76% relative humidity for 160 days; (2) chemical hardening—materials were soaked in 0.1 M acetate buffer (pH 4.0) at 37 °C for 1–7 h. The cooking time curves generated by chemical hardening had shapes similar to those obtained by storage hardening; both procedures were equally capable of discriminating chickpea varieties based on their susceptibility to develop the HTC condition. Chemical hardening might be useful for screening new chickpea varieties; its advantage over the storage method is its rapidity.© 2001 Society of Chemical Industry
Aflatoxins, ochratoxin A and zearalenone in Brazilian corn cultivars
Authors: Machinski Miguel , Valente Soares Lucia M , Sawazaki Eduardo , Bolonhezi Denizart , Castro Jairo L , Bortolleto Nelson 
Published: August 2002

AbstractPast surveys indicated that the occurrence of aflatoxins, zearalenone and ochratoxin A was not a problem in corn and corn products in the state of São Paulo, Brazil. However, according to recent studies, a change in pattern has been detected. To obtain a better overview, these toxins were searched for in 110 samples of freshly harvested corn, corresponding to 48 commercial cultivars planted at three different locations in the state. Aflatoxin contamination was found in 60 (54.5%) of the samples, in levels ranging from 6 to 1600 µg kg−1 aflatoxin B1. Insect control was exercised, so this was not the main route of corn infection. Endosperm type, germplasm type, number of days to flowering, and length of time the mature corn remained in the field had no effect on aflatoxin contamination. Ochratoxin A was found in two samples (206 and 128 µg kg−1) and zearalenone in one sample (4640 µg kg−1). Possible causes of the increase in aflatoxin levels may lie in the changing nature of the commercial cultivars employed, associated with the forsaking of the original landraces, and in a change in the toxigenicity pattern of the corn mycoflora Aspergillus flavus/Aspergillus parasiticus prevailing strains.© 2001 Society of Chemical Industry
Preparation of flavanol‐rich green tea extract by precipitation with AlCl3
Authors: Chen Zhen‐Yu , Wang Shu , Lee Kwong Man Simon , Huang Yu , Ho Walter K K 
Published: August 2002

AbstractThe aim of this study was to use AlCl3 in the extraction of green tea flavanols (GTFs) from longjing green tea and examine the factors that influence the yield of GTF extract. Dry tea leaves were soaked in hot distilled water and the infusion was obtained by filtration. To the tea infusion, varying amounts of AlCl3 were added, causing precipitation of GTFs. After adjusting the pH to 4.0–6.5 and centrifugation, the yellow precipitate was collected. Sulphuric acid solution (40%) was then used to dissolve the GTFs from the yellow precipitate. The GTF solution was extracted using an equal volume of ethyl acetate. After the removal of ethyl acetate using a rotary evaporator, the GTF extract was redissolved in distilled water and the whole process was repeated. The resulting GTF extract was freeze‐dried. It was found that the amount of AlCl3 used and the pH and temperature of the precipitation mixture significantly affected the yield and purity of GTF extract. A yield of 9.6 g extract per 100 g dry tea leaves with GTFs > 94% could be obtained if AlCl3 was used in the ratio of 15 g per 100 g equivalent dry tea leaves and the pH of the precipitation mixture was adjusted to 5.5 at 30 °C.© 2001 Society of Chemical Industry
A political approach to relationship marketing: case study of the Storsjöyran festival
Authors: Larson Mia 
Published: August 2002

AbstractThis study is concerned with interorganisational aspects of relationship marketing, which, in turn, has led to a focus on political aspects, i.e. on interests, conflicts and power in a project network consisting of actors marketing a festival. A metaphor of a project network, the political market square (PSQ), is introduced and used in the analysis of a case study of the Storsjöyran Festival in Sweden. In order to understand the politics and the dynamics in the PSQ, actors' access is discussed. Moreover, interactions between actors, which are to be regarded as cooperative or characterised by power games, and the degree of change dynamics, contribute to understanding dynamic political processes. Identified political processes were gatekeeping, negotiations, coalition building, building of trust and identify building. These processes, and actors' entries and exits between the PSQ and a wider network, caused turbulence and changed the power structure of the PSQ. The turbulence fostered change and innovations that resulted in product development. However, actors' shared identities and a stable, positive image of the festival moderated the turbulence. Copyright © 2002 John Wiley & Sons, Ltd.
UV absorption spectra of HO2, CH3O2, C2H5O2, and CH3C(O)CH2O2 radicals and mechanism of the reactions of F and Cl atoms with CH3C(O)CH3
Authors: Nielsen Ole J. , Johnson Matthew S. , Wallington Timothy J. , Christensen Lene K. , Platz Jesper 
Published: August 2002

AbstractPulse radiolysis techniques were used to measure the gas phase UV absorption spectra of the title peroxy radicals over the range 215–340 nm. By scaling to σ(CH3O2)240 nm = (4.24 ± 0.27) × 10−18, the following absorption cross sections were determined: σ(HO2)240 nm = 1.29 ± 0.16, σ(C2H5O2)240 nm = 4.71 ± 0.45, σ(CH3C(O)CH2O2)240 nm = 2.03 ± 0.22, σ(CH3C(O)CH2O2)230 nm = 2.94 ± 0.29, and σ(CH3C(O)CH2O2)310 nm = 1.31 ± 0.15 (base e, units of 10−18 cm2 molecule−1). To support the UV measurements, FTIR‐smog chamber techniques were employed to investigate the reaction of F and Cl atoms with acetone. The F atom reaction proceeds via two channels: the major channel (92% ± 3%) gives CH3C(O)CH2 radicals and HF, while the minor channel (8% ± 1%) gives CH3 radicals and CH3C(O)F. The majority (>97%) of the Cl atom reaction proceeds via H atom abstraction to give CH3C(O)CH2 radicals. The results are discussed with respect to the literature data concerning the UV absorption spectra of CH3C(O)CH2O2 and other peroxy radicals. © 2002 Wiley Periodicals, Inc. Int J Chem Kinet 34: 283–291, 2002
Building landscapes: village development in Zimbabwe
Authors: Moyo S. 
Published: August 2002

AbstractThis paper argues that there is a need to fill a specific empirical and conceptual gap in land policy analysis in Zimbabwe. This ‘gap’ has arisen from the predominantly macro level economic theoretical perspectives on the land question, and from an inadequate conceptualization of the local level character of the land debate in Zimbabwe. The purpose of this paper is to stress the importance of focusing on the land question from the standpoint of the peasant householders in the Communal Areas (CAs). These issues are raised through the examination of land use and land‐use history in Mhezi Ward in Makoni District, Zimbabwe. This paper does not comment on the recent political moves to redistribute 1471 Large Scale Commercial Farms (LSCF) as this process must be discussed in another debate. Copyright © 2001 John Wiley & Sons, Ltd.
Photomechanical transdermal delivery of insulin in vivo
Authors: Lee Shun , McAuliffe Daniel J. , Mulholland Stephen E. , Doukas Apostolos G. 
Published: August 2002

AbstractBackground and ObjectivePrevious studies have shown that photomechanical waves transiently permeabilize the stratum corneum in vivo. The aim of the present work was to investigate the potential of photomechanical waves for systemic drug delivery.Study Design/Materials and MethodsPhotomechanical waves were generated by ablation of a polystyrene target by a Q‐switched ruby laser. Systemic insulin delivery in a streptozotocin‐diabetic rat model was monitored by measuring the blood glucose level.ResultsAfter photomechanical insulin delivery, the blood glucose decreased 80  ±  3% and remained below 200 mg/dl for more than 3 hours. Whereas in control experiments (for which insulin was applied without photomechanical waves), there was no dramatic change in the blood glucose (standard deviation of measurements over 4 hours was 7%).ConclusionThe application of the photomechanical waves allowed ∼6‐kDa protein molecules (insulin) to pass through the stratum corneum and into the systemic circulation. Lasers Surg. Med. 28:282–285, 2001. © 2001 Wiley‐Liss, Inc.
Use of osmotically active agents to alter optical properties of tissue: Effects on the detected fluorescence signal measured through skin
Authors: Vargas Gracie , Chan Kin F. , Thomsen Sharon L. , Welch A.J. 
Published: August 2002

AbstractBackground and ObjectiveHyper‐osmotic chemical agents were used to study the effects of transient tissue scattering on the remitted fluorescence emission intensity from a target placed under a tissue sample.Study Design/Materials and MethodsA fluorescent film was placed underneath in vitro and in vivo samples of hamster skin, and the remitted fluorescent signal traveling to the tissue surface was monitored over time as the tissue was treated with an osmotically active agent.ResultsThe detected fluorescent signal increased as the scattering in tissue samples was substantially reduced. The increase was greater for dimethyl sulfoxide than glucose or glycerol. It was not statistically different between in vivo skin and in vitro skin.ConclusionsThe study shows how chemical agents can be used to improve the detected signal for a specific optical application. It could be useful in a number of optical therapeutic and diagnostic applications that can benefit from an increase in the penetration depth of light. Lasers Surg. Med. 29:213–220, 2001. © 2001 Wiley‐Liss, Inc.
Sequential changes in hepatocarcinogenesis induced by diethylnitrosamine plus thioacetamide in Fischer 344 rats: Induction of gankyrin expression in liver fibrosis, pRB degradation in cirrhosis, and methylation of p16INK4A exon 1 in hepatocellular carcinoma
Authors: Park Tae Jun , Kim Hong Seok , Byun Kyu Hee , Jang Ja June , Lee Yun Sil , Lim In Kyoung 
Published: August 2002

AbstractTo clarify the sequential changes in pRB and p16 during different stages of hepatocarcinogenesis such as fibrosis, cirrhosis, hepatocellular adenoma (HCA), and hepatocellular carcinoma (HCC), male Fischer 344 rats were singly injected with diethylnitrosamine (DEN), immediately followed with phenobarbital for 1 wk and then thioacetamide (TAA) for 39 wk in drinking water. Rats were killed at 9, 20, 30, and 40 wk after DEN initiation and changes of pRB level, p16 gene hypermethylation, and in vivo gankyrin expression were examined. Histologic examination showed stepwise appearances of fibrosis, cirrhosis, HCA, and HCC at weeks 9, 20, 30, and 40, respectively. Hypermethylation of p16 exon 1 was not found until HCA but appeared in 50% of the rats with HCC accompanied by complete loss of its mRNA expression. The amount of glutathione S‐transferase–gankyrin bound to pRB and pRB degradation in the liver depended on the concentration of gankyrin and incubation time. Gankyrin expression preceded pRB degradation in liver cirrhosis. In conclusion, gankyrin expression induced in liver fibrosis accelerated the degradation of pRB during liver cirrhosis, and inactivation of p16 exon 1 by DNA hypermethylation occurred during the progression of tumor cells to poorly differentiated HCC. Inactivation of pRB and/or p16 resulted in complete loss of regulation in the cell‐division cycle during early and late stages, respectively, of hepatocarcinogenesis. Mol. Carcinog. 30:138–150, 2001. © 2001 Wiley‐Liss, Inc.
Involvement of the medial pallidum in focal myoclonic dystonia: A clinical and neurophysiological case study
Authors: Liu Xuguang , Griffin Ivan C. , Parkin Simon G. , Miall R. Christopher , Rowe Jeremy G. , Gregory Ralph P. , Scott Richard B. , Aziz Tipu Z. , Stein John F. 
Published: August 2002

AbstractWe successfully treated a patient with familial myoclonic dystonia (FMD), which primarily affected his neck muscles, with bilateral deep brain stimulation (DBS) to the medial pallidum, and investigated the role of the medial pallidum in FMD. A patient with FMD underwent bilateral implantation of DBS electrodes during which field potentials (FPs) in the medial pallidum and electromyograms (EMGs) from the affected neck muscles were recorded. The effects of high‐frequency DBS to the medial pallidum on the FMD were also assessed by recording EMGs during and immediately after implantation, as well as 6 days and 8 weeks postoperatively. During spontaneous myoclonic episodes, increased FPs oscillating at 4 and 8 Hz were recorded from the medial pallidum; these correlated strongly with phasic EMG activity at the same frequencies in the contralateral affected muscles. The EMG activity was suppressed by stimulating the contralateral medial pallidum at 100 Hz during the operation and continuous bilateral DBS from an implanted stimulator abolished myoclonic activity even more effectively postoperatively. The phasic pallidal activity correlated with and led the myoclonic muscle activity, and the myoclonus was suppressed by bilateral pallidal DBS, suggesting that the medial pallidum was involved in the generation of the myoclonic activity. High‐frequency DBS may suppress the myoclonus by desynchronising abnormal pallidal oscillations. This case study has significant clinical implications, because at present, there is no effective treatment for focal myoclonic dystonia. © 2002 Movement Disorder Society.
Assessing state parity legislation
Authors: Zuvekas Samuel H. 
Published: August 2002

AbstractThe temptation is great, but premature, to conclude from the Sturm study that parity mandates had no effect on access and insurance coverage for the mentally ill. The study lacks statistical power for those directly covered by the mandates, and it is unlikely adequate power exists for those only indirectly affected. The inclusion of the uninsured, Medicaid enrollees, and privately covered individuals not subject to the mandates, and the imprecise outcome measures, increase the likelihood that other factors dominate parity. The timing of implementation in some states is also problematic. But Sturm asks the right questions and future waves of the Healthcare for Communities survey and other data will be better able to address them. Copyright © 2000 John Wiley & Sons, Ltd.