bluuebunny/crossref_metadata_2025_split huggingface dataset:
Differential effects of phencyclidine application on secretogranin II expression in organotypic slices of rat prefrontal cortex
Authors: Hinterhoelzl Josef K. , Salimi Kayvon , Humpel Christian , Singewald Nicolas , Adlassnig Christine , Fischer‐Colbrie Reiner , Fleischhacker Wolfgang W. , Marksteiner Josef 
Published: September 2003

AbstractPhencyclidine (PCP) is a non‐competitive NMDA glutamate receptor antagonist that induces psychotomimetic effects in humans and experimental animals. Chronic PCP exposure elicits signs of persistently altered frontal brain activity and related behaviors which are also seen in patients with schizophrenia. Secretogranin II (sg II) belongs to the chromogranin family of proteins that exist in large dense core vesicles in nervous tissue. In the brain, 90% of sg II is processed to the small peptide secretoneurin. We previously detected differential effects of single‐dose and subchronic PCP administration on sg II expression in the rat prefrontal cortex (PFC). In the present study, we applied PCP to organotypic PFC slices. PCP application for 28 h induced decreased tissue and culture medium secretoneurin content. In contrast, incubation with the adenylate cyclase activator forskolin caused significantly increased secretoneurin levels after 8 h. PCP for 4 h followed by 24 h without PCP resulted in increased culture medium secretoneurin content but no change in tissue levels. sg II mRNA expression was decreased after 28 h PCP application in cortical neurons. Immunohistochemical and TUNEL staining profiles indicated that the alterations were not due to neurodegeneration. PCP for 5 days changed neither the secretoneurin tissue or culture medium levels, nor the sg II mRNA expression. These results demonstrate that PCP modulates sg II expression in PFC tissue in the absence of afferent inputs and that the nature of these changes is dependent upon the duration of exposure to and/or withdrawal from PCP.
Protective effects of lysophosphatidic acid (LPA) on chronic ethanol‐induced injuries to the cytoskeleton and on glucose uptake in rat astrocytes
Authors: Tomás Mónica , Lázaro‐Diéguez Francisco , Durán Juan M. , Marín Pilar , Renau‐Piqueras Jaime , Egea Gustavo 
Published: September 2003

AbstractEthanol induces severe alterations in membrane trafficking in hepatocytes and astrocytes, the molecular basis of which is unclear. One of the main candidates is the cytoskeleton and the molecular components that regulate its organization and dynamics. Here, we examine the effect of chronic exposure to ethanol on the organization and dynamics of actin and microtubule cytoskeletons and glucose uptake in rat astrocytes. Ethanol‐treated cells cultured in either the presence or absence of fetal calf serum showed a significant increase in 2‐deoxyglucose uptake. Ethanol also caused alterations in actin organization, consisting of the dissolution of stress fibres and the appearance of circular filaments beneath the plasma membrane. When lysophosphatidic acid (LPA), which is a normal constituent of serum and a potent intercellular lipid mediator with growth factor and actin rearrangement activities, was added to ethanol‐treated astrocytes cultured without fetal calf serum, it induced the re‐appearance of actin stress fibres and the normalization of 2‐deoxyglucose uptake. Furthermore, ethanol also perturbed the microtubule dynamics, which delayed the recovery of the normal microtubule organization following removal of the microtubule‐disrupting agent nocodazole. Again, pre‐treatment with LPA prevented this alteration. Ethanol‐treated rodent fibroblast NIH3T3 cells that constitutively express an activated Rho mutant protein (GTP‐bound form) were insensitive to ethanol, as they showed no alteration either in actin stress‐fibre organization or in 2‐deoxyglucose uptake. We discuss the putative signalling targets by which ethanol could alter the cytoskeleton and hexose uptake and the cytoprotective effect of LPA against ethanol‐induced damages. The latter opens the possibility that LPA or a similar non‐hydrolysable lipid derivative could be used as a cytoprotective agent against the noxious effects of ethanol.
Using novel variation in Brassica species to reduce agricultural inputs and improve agronomy of oilseed rape—a case study in pod shatter resistance
Authors: Morgan Colin , Bavage Adrian , Bancroft Ian , Bruce David , Child Robin , Chinoy Catherine , Summers Jacky , Arthur Eddie 
Published: September 2003

AbstractOilseed rape is a very undeveloped crop with regard to efficiency of production and the agronomic practice used to maximize its potential. The genetic potential to modify oilseed rape is limited by the narrow genetic base found within the breeding gene pool, resulting in limited novel variation available for exploitation. Novel variation is, however, present in wild diploid ancestors of oilseed rape and has been made available by developing synthetic Brassica napus. This is illustrated through the use of this material to develop an understanding of pod shattering which is one of the most agronomically important characteristics of the crop. Through a variety of approaches it is shown how progress has been made to understand this trait and how this understanding is being used to improve the crop such that efficiency of production will be enhanced.
Dehydroascorbate Uptake Activity Correlates with Cell Growth and Cell Division of Tobacco Bright Yellow-2 Cell Cultures
Authors: Horemans Nele , Potters Geert , De Wilde Leen , Caubergs Roland J. 
Published: September 2003

Abstract
Recently, ascorbate (ASC) concentration and the activity of a number of enzymes from the ASC metabolism have been proven to correlate with differences in growth or cell cycle progression. Here, a possible correlation between growth and the activity of a plasma membrane dehydroascorbate (DHA) transporter was investigated. Protoplasts were isolated from a tobacco (Nicotiana tabacum) Bright Yellow-2 cell culture at different intervals after inoculation and the activity of DHA transport was tested with 14C-labeled ASC. Ferricyanide (1 mm) or dithiothreitol (1 mm) was included in the test to keep the external 14C-ASC in its oxidized respectively reduced form. Differential uptake activity was observed, correlating with growth phases of the cell culture. Uptake of DHA in cells showed a peak in exponential growth phase, whereas uptake in the presence of dithiothreitol did not. The enhanced DHA uptake was not due to higher endogenous ASC levels that are normally present in exponential phase because preloading of protoplasts of different ages did not affect DHA uptake. Preloading was achieved by incubating cells before protoplastation for 4 h in a medium supplemented with 1 mm DHA. In addition to testing cells at different growth phases, uptake of DHA into the cells was also followed during the cell cycle. An increase in uptake activity was observed during M phase and the M/G1 transition. These experiments are the first to show that DHA transport activity into plant cells differs with cell growth. The relevance of the data to the action of DHA and ASC in cell growth will be discussed.
Electrical Potentials of Plant Cell Walls in Response to the Ionic Environment
Authors: Shomer Ilan , Novacky Anton J. , Pike Sharon M. , Yermiyahu Uri , Kinraide Thomas B. 
Published: September 2003

AbstractElectrical potentials in cell walls (ψWall) and at plasma membrane surfaces (ψPM) are determinants of ion activities in these phases. The ψPM plays a demonstrated role in ion uptake and intoxication, but a comprehensive electrostatic theory of plant-ion interactions will require further understanding of ψWall. ψWall from potato (Solanum tuberosum) tubers and wheat (Triticum aestivum) roots was monitored in response to ionic changes by placing glass microelectrodes against cell surfaces. Cations reduced the negativity of ψWall with effectiveness in the order Al3+ &gt; La3+ &gt; H+ &gt; Cu2+ &gt; Ni2+ &gt; Ca2+ &gt; Co2+ &gt; Cd2+ &gt; Mg2+ &gt; Zn2+ &gt; hexamethonium2+ &gt; Rb+ &gt; K+ &gt; Cs+ &gt; Na+. This order resembles substantially the order of plant-root intoxicating effectiveness and indicates a role for both ion charge and size. Our measurements were combined with the few published measurements of ψWall, and all were considered in terms of a model composed of Donnan theory and ion binding. Measured and model-computed values for ψWall were in close agreement, usually, and we consider ψWall to be at least proportional to the actual Donnan potentials. ψWall and ψPM display similar trends in their responses to ionic solutes, but ions appear to bind more strongly to plasma membrane sites than to readily accessible cell wall sites. ψWall is involved in swelling and extension capabilities of the cell wall lattice and thus may play a role in pectin bonding, texture, and intercellular adhesion.
A Developmental Response to Pathogen Infection in Arabidopsis
Authors: Korves Tonia M. , Bergelson Joy 
Published: September 2003

Abstract
We present evidence that susceptible Arabidopsis plants accelerate their reproductive development and alter their shoot architecture in response to three different pathogen species. We infected 2-week-old Arabidopsis seedlings with two bacterial pathogens, Pseudomonas syringae and Xanthomonas campestris, and an oomycete, Peronospora parasitica. Infection with each of the three pathogens reduced time to flowering and the number of aerial branches on the primary inflorescence. In the absence of competition, P. syringae and P. parasitica infection also increased basal branch development. Flowering time and branch responses were affected by the amount of pathogen present. Large amounts of pathogen caused the most dramatic changes in the number of branches on the primary inflorescence, but small amounts of P. syringae caused the fastest flowering and the production of the most basal branches. RPS2 resistance prevented large changes in development when it prevented visible disease symptoms but not at high pathogen doses and when substantial visible hypersensitive response occurred. These experiments indicate that phylogenetically disparate pathogens cause similar changes in the development of susceptible Arabidopsis. We propose that these changes in flowering time and branch architecture constitute a general developmental response to pathogen infection that may affect tolerance of and/or resistance to disease.
On Friendship: Derrida, Foucault, and the Practice of Becoming
Authors: Webb David 
Published: September 2003

AbstractThe aim of this paper is to question Derrida's approach to the theme of friendship and to set out an alternative reading drawn from the work of Foucault on the care of the self. Derrida's treatment of friendship as aporetic, though faithful to a long tradition of writing on friendship, depends on the use of a formal language that, I argue, exacerbates the difficulties inherent in the theme of friendship. Moreover, it is not clear that the experience of friendship always displays the temporal form given to this aporetic structure. In contrast, Foucault's work suggests that friendship emerges from the complex system of relations that condition who we are and how we can act. Friends are those with whom we work on the historical conditions of our existence, and those with whom we share the practice of becoming who we are.
Ethical Life
Authors: Peperzak Adriaan 
Published: September 2003

AbstractKant's formalism remains unreal if it cannot be concretized in a historical ethos. An ethos belongs—with texts, contexts, structures, processes, networks, etc.—to an economy of customs and opinions, which presupposes that participating individuals have been and are being initiated and acculturated to it. The analysis of education, transmission, and transition unveils the irreducible—noneconomic and non-(con)textual— essence of addressing and interlocution, without which no culture could exist. The otherness that is involved implies, but is not confined to, "you." The third and I myself are also other by imposing the same inescapable responsibility for them on me.
Nature's Metabolism: On Eating in Derrida, Agamben, and Spinoza
Authors: Klein Julie 
Published: September 2003

AbstractThis article studies a series of provocative references to Spinoza by Jacques Derrida and Giorgio Agamben. For both contemporary philosophers, the context is discussions of eating, a subject matter that turns out to involve such central issues as subjectivity, nature, ethics, and teleology. Each situates Spinoza in a counter-history of philosophy and suggests that Spinoza constitutes an important resource for contemporary reflections. Through an analysis of the three philosophers' texts about eating, nutrition, and being metabolized, I argue that Spinoza's nonteleological, nonhumanistic conception of nature remains a radical possibility, even in the face of contemporary attempts to think outside the canonical discourses of transcendental subjectivity, technological reason, and teleological ethics. Spinoza's position is, in the end, more uncompromising than that of Derrida or Agamben.
Mechanical evolution of the rotating biological contactor into the 21st century
Authors: Mba D 
Published: September 2003

This paper presents a review on the evolution of the mechanical design of rotating biological contactors (RBCs) within the UK. The findings documented have been taken from the biggest mechanical survey on RBCs ever undertaken worldwide and focuses on 300 operational units. The paper looks at the main components of the RBC and discusses the evolution of each member. Mechanical deficiencies associated with each design are briefly presented, giving an insight into reasons for improvements. This is the only known document that details changes in design philosophy employed over the last 30 years, with illustrative examples. For the purpose of this review, the mechanical evolution of the RBC is focused on three primary sections: media panel designs, media support structures, and auxiliary support systems including bearings, power units, and transmission systems. It is shown that the evolution of media panels has largely been directed by economies of manufacture and operational requirements. However, advances in the mechanical design of the RBC supporting structure, while dependent on media type, are largely influenced by overcoming known mechanical deficiencies as well as increasing operational life. This paper depicts the current technology and practice of UK-based manufacturers and details reasons for mechanical deficiencies.
Transient elastohydrodynamic point contact analysis using a new coupled differential deflection method Part 2: Results
Authors: Holmes M. J. A. , Evans H. P. , Hughes T. G. , Snidle R. W. 
Published: September 2003

The paper presents results obtained using a transient analysis technique for point contact elastohydrodynamic lubrication (EHL) problems based on a formulation that effectively couples the elastic and hydrodynamic equations. Results are presented for transverse ground surfaces in an elliptical contact that show severe film thinning at the transverse limits of the contact area. This thinning is caused by transverse (side) leakage of the lubricant from the contact in the remaining deep valley features. Comparison is made between the elliptical contact results on the entrainment centreline and the equivalent line contact analysis. This confirms the importance of edge effects as a likely cause of film collapse and scuffing failure. The surface profiles used in the analysis are taken from test discs used in scuffing experiments and from gears used in micropitting tests. Side leakage is found to be sufficiently severe to cause microasperity contact in the numerical examples presented. This contact mainly occurs close to the edges of the corresponding Hertzian area and correlates in position with the location at which scuffing is found to first occur in the earlier experiments. Comparisons are made with other numerical results for point contact configurations with sinusoidally varying surface features obtained by Zhu (2000) and considerable differences are seen in the calculated extent of asperity contact. The differences are thought to be due to the simplified treatment of the lubrication equation adopted by Zhu.
Changes in serum markers of bone turnover during normal pregnancy
Authors: Kaur Malveen , Godber Ian M , Lawson Nigel , Baker Phillip N , Pearson Derek , Hosking David J 
Published: September 2003

Background: Maternal calcium homeostasis adapts during pregnancy to provide for the needs of the growing fetal skeleton. Wide selections of bone turnover markers are currently available to assess the changes taking place; here, data are presented on two serum-based markers. Methods: The use of serum-based biochemical bone turnover markers during pregnancy was assessed in a cohort of 41 women recruited prior to conception. Serum N-terminal extension peptide of procollagen (P1NP) was used to monitor bone formation and serum β-crosslaps (S-CTX) used to assess resorption. Blood samples were measured at five time points from a pre-conceptual baseline, through pregnancy, to the final sample, which was taken within 1 week of delivery. Results: An initial decrease from the baseline in both P1NP and S-CTX was observed at 12 weeks; however, it is suggested that this may be due to the haemodilutional effect of pregnancy rather than a true change in bone turnover. Significant increases from the baseline of both analytes were observed by 36 weeks (P1NP, P = 0.013; S-CTX, P = 0.002), when the calcium demands of the fetus are greatest. Conclusions: This study illustrates the use of serum-based bone turnover markers to assess turnover during normal pregnancy, a time when ionizing radiation cannot be used to assess bone turnover.
Macroenzyme detection by polyethylene glycol precipitation
Authors: Davidson D Fraser , Watson Dawn JM 
Published: September 2003

Background: The presence of macroenzymes can cause significant diagnostic confusion and their detection can involve relatively cumbersome analytical procedures. Methods: Using a simplified polyethylene glycol precipitation technique and isoenzyme electrophoresis, this report describes the construction of reference ranges of precipitable activity for each of seven commonly measured enzymes in plasma. Results: The proposed reference ranges are reported. Since introducing the protocol, 12 cases of macroenzymaemia have been encountered. Three typical case histories are described in some detail. Conclusions: The polyethylene glycol precipitation method has thus far proved to be a simple and effective additional test for the detection of macroenzymes when the plasma enzyme activity is elevated.
Routine transferrin saturation measurement in liver clinic patients increases detection of hereditary haemochromatosis
Authors: Poullis A , Moodie SJ , Ang L , Finlayson CJ , Levin GE , Maxwell JD 
Published: September 2003

Background: Hereditary haemochromatosis (HH) is one of the commonest genetic disorders in European populations. Transferrin saturation (TFS) measurement has been advocated as a phenotypic screening test to improve detection. We undertook a prospective study to examine the value of routine TFS measurement in detecting new cases of HH in unselected liver clinic attenders. Methods: Non-fasting TFS was measured in new patients. HH mutations were determined in those with elevated TFS (>45%) and all who underwent liver biopsy. Liver biopsy was performed in 349 patients, including all found to be C282Y homozygotes or compound heterozygotes. Results: Of 667 new patients attending over 5 years, 156 had TFS >45% and 18 had significant mutations (12 C282Y homozygotes and six compound heterozygotes). Eleven of the 12 C282Y homozygotes identified had an elevated TFS and 10 had significant hepatic siderosis. Only two of the six compound heterozygotes had an elevated TFS and hepatic siderosis. Conclusions: The prevalence of new HH cases in patients of European origin attending a liver clinic, detected by phenotypic screening over a 5-year period, was 2.8%. All were identified by a TFS cut off >45%, but TFS >60% provided the best combination of sensitivity and specificity for detecting C282Y homozygosity.
Use of the Bayer DCA 2000+ for the measurement of glycated haemoglobin in a remote Australian Aboriginal community
Authors: Shemesh T , Piers LS , O'Dea K 
Published: September 2003

Background: Good glycaemic control in type 2 diabetes can reduce both morbidity and mortality, and monitoring of glycated haemoglobin A1c (HbA1c) is currently recommended for this purpose. Methods: Haemoglobin A1c can be measured using the portable Bayer DCA 2000+. As part of a community-based screening project for chronic diseases, subjects with impaired fasting glucose concentrations or diabetes had their HbA1c concentration measured on the analyser. HbA1c measurements were also made in a laboratory using cation-exchange high-performance liquid chromatography. Results were then compared to those obtained in the field. HbA1c values were loge transformed to obtain a normal distribution. Results: Mean (95% confidence interval) HbA1c measured on the DCA 2000+ ( n = 39) was 6.3% (5.8, 6.9%), while that measured in the laboratory was 6.5% (6.0, 7.0%). The correlation coefficient ( r) between the measurements was 0.96 ( P < 0.01). Bland-Altman analysis revealed that the DCA 2000+ estimate of HbA1c could be used interchangeably with that from the laboratory (mean bias = 0.1%, limits of agreement - 1.1, 0.8%). The sensitivity, specificity and positive predictive value of the DCA 2000+ estimate of HbA1c using a cut-off value of <7% for adequate glycaemic control, were all 100%. Conclusions: The DCA 2000+ may be used to measure HbA1c in remote communities.
Colluvial deposits in dry valleys of southern England as proxy indicators of paleoenvironmental and land‐use change
Authors: Wilkinson Keith N. 
Published: September 2003

AbstractInvestigations of colluvial sequences infilling the dry valleys of the southern English chalk escarpment have been undertaken since the late 1950s. Chalkland environments are characterized by a rich prehistoric cultural record and, because of poor pollen preservation in the highly calcareous chalkland sediments, molluscan analysis of such deposits has frequently been undertaken to reconstruct past land use and environment. Archaeologists often base their interpretations of past chalkland environments on these reconstructions. In order to test the value of this proxy data source, seven dry valley systems in southern England were investigated using a combination of lithostratigraphic and biostratigraphic techniques. The results of this study demonstrate that patterns of sedimentation are similar within valley systems, but that the mechanisms and chronology of deposition vary between valleys. The differences are probably caused by a combination of factors, including variations in past land use, the impact of storm activity, and local topography. It can therefore be argued that it is unwise to use dry valley sequences and their accompanying biological assemblages for regional environmental reconstruction, although the data are invaluable when examining land use on a local level—the scale at which most archaeological projects in the United Kingdom are carried out. © 2003 Wiley Periodicals, Inc.