bluuebunny/crossref_metadata_2025 huggingface dataset:
The importance of the air temperature variable for the snowmelt runoff modelling using the SRM
Authors: Richard C. , Gratton D. J.
Published: August 2002

Runoff regimes in most northern basins are controlled by the melting snow cover. A common method for evaluating runoff consists in correlating ambient air temperature and recorded hydrometric gauge values. The air temperature is the principal variable to estimate the importance of the melting of the snow cover when using a global conceptual model such as the snowmelt runoff model (SRM). The temperature, which is often only measured at one weather station, must be extrapolated to the whole basin according to some kind of lapse rate. This extrapolation often assumes that air temperature is representative for a wide region, which is often not the case. The estimation of temperature values is critical, especially for large basins where the surface processes are largely influenced by a forest cover. This project has two objectives: (1) applying a mostly high mountain SRM to the Batiscan River Basin, in the Province of Québec, an area occupied by a forest with a rolling hill topography; (2) investigate the impact of the extrapolation strategy for estimating temperature values and its importance in the runoff modelling. A statistical comparison between the different modelling attempts was performed. This allowed us to obtain a sensitivity analysis of the snow runoff modelling in relation to the extrapolation of the temperature values. Our results showed that the weather station, used to perform the runoff modelling, should be located in the most representative land cover of the study area. Otherwise, the values of a synthetic regional weather station were more reliable for the modelling. Finally, before pursuing any snowmelt modelling with the SRM, the temperature values must be evaluated based on the location of the weather station to see if they are representative of the total study area. Copyright © 2001 John Wiley & Sons, Ltd.
Comparison of methods for applying the Priestley–Taylor equation at a regional scale
Authors: Castellvi F. , Stockle C. O. , Perez P. J. , Ibañez M.
Published: August 2002

The scenario assumed for this study was that of a region with a complete or first‐order weather station surrounded by a network of second‐order stations, where only monthly air temperature data were available. The objective was to evaluate procedures to estimate the monthly α parameter of the Priestley–Taylor equation in the second‐order stations by adjusting and extrapolating α values determined at the first‐order station. These procedures were applied in two climatic zones of north‐east Spain with semi‐arid continental and semi‐arid Mediterranean climates, respectively. Procedure A assumed α to be constant over each zone for each month (direct extrapolation). Procedure B accounted for differences in vapour pressure deficit and available energy for evapotranspiration between the first‐ and second‐order stations. Procedure C was based on equating the Penman–Monteith (P–M) and Priestley–Taylor (P–T) equations on a monthly basis to solve for α. Methods to estimate monthly mean vapour pressure deficit, net radiation and wind speed were developed and evaluated. A total of 11 automated first‐order weather stations with a minimum period of record of 6 years (ranging from 6 to 10 years) were used for this study. Six of these stations were located in the continental zone and five in the Mediterranean zone. One station in each zone was assumed to be first‐order whereas the remainder were taken as second‐order stations. Monthly α parameters were calibrated using P–M reference crop evapotranspiration (ET0) values, calculated hourly and integrated for monthly periods, which were taken as ‘true’ values of ET0. For the extrapolation of monthly α parameters, procedure A was found to perform slightly better than procedure B in the Mediterranean zone. The opposite was true in the continental zone. Procedure C had the worst performance owing to the non‐linearity of the P–M equation and errors in the estimation of monthly available energy, vapour pressure deficit and wind speed. Procedures A and B are simpler and performed better. Overall, monthly P–T ET0 estimates using extrapolated α parameters and Rn−G values were in a reasonable agreement with P–M ET0 calculated on an hourly basis and integrated for monthly periods. The methods presented for the spatial extrapolation of monthly available energy, vapour pressure deficit and wind speed from first‐ to second‐order stations could be useful for other applications. Copyright © 2001 John Wiley & Sons, Ltd.
Modelling transport of dissolved silica in a forested headwater catchment: the effect of hydrological and chemical time scales on hysteresis in the concentration–discharge relationship
Authors: Hornberger George M. , Scanlon Todd M. , Raffensperger Jeff P.
Published: August 2002

The relationship between concentration c and discharge Q in a stream is one of the aspects of hydrochemical catchment response that has been used widely as a diagnostic. In particular, loops in the c–Q curve, commonly referred to as hysteresis loops, are used to infer particular mixing patterns. At the South Fork of Brokenback Run (SFBR) in the Shenandoah National Park, Virginia, we have evidence that stream dynamics reflect a system composed of an ephemeral subsurface stormflow zone perched above a perennial water table. The relationship between dissolved silica and stream discharge exhibits hysteresis in the clockwise (CW) direction. Modelling this relationship in the context of three‐component mixing with constant‐concentration end members failed to reproduce the observed c–Q pattern. In this paper we examine the possibility that temporal variation in soil‐water concentrations of silica can explain how CW hysteresis loops in the c–Q curve can arise. In particular, we examine the role of the ratio of a hydrological time scale to a chemical time scale in determining the nature of hysteresis loops. The CW loops that we observe in SFBR can be explained by time variability in soil‐water concentrations only if the chemical (leaching) time constant is less than (or only slightly greater than) the hydrological time constant. The near equality of these time constants is consistent with reports from hydrological measurements and leaching experiments. Copyright © 2001 John Wiley & Sons, Ltd.
Quantitative evaluation of strategies for erosion control on a railway embankment batter
Authors: Gyasi‐Agyei Y. , Sibley J. , Ashwath N.
Published: August 2002

Strategies for erosion control on a railway embankment batter (side slope) are quantitatively evaluated in this paper. The strategies were centred on control (‘do nothing’ treatment), grass seeding, gypsum application, jute mat (an erosion control blanket) placement and planting hedgerows of Monto vetiver grass. Rainfall and runoff were monitored at 1 min intervals on 10 m wide embankment batter plots during 1998 and 1999. Total bedload and suspended sediment eroded from the plots were also measured but only for a group of storm events within sampling intervals. It has been demonstrated that vetiver grass is not cost‐effective in controlling erosion on railway batters within Central Queensland region. Seeding alone could cause 60% reduction in the erosion rate compared with the control treatment. Applying gypsum to the calcium‐deficient soil before seeding yielded an additional 25% reduction in the erosion rate. This is the result, primarily, of 100% grass cover establishment within seven months of sowing. Therefore, for railway embankment batter erosion control, the emphasis needs to be on rapid establishment of 100% grass cover. For rapid establishment of grass cover, irrigation is necessary during the initial stages of growth as the rainfall is unpredictable and the potential evaporation exceeds rainfall in the study region. The risk of seeds and fertilizers being washed out by short‐duration and high‐intensity rainfall events during the establishment phase may be reduced by the use of erosion control blankets on sections of the batters. Accidental burning of grasses on some plots caused serious erosion problems, resulting in very slow recovery of grass growth. It is therefore recommended that controlled burning of grasses on railway batters should be avoided to protect batters from being exposed to severe erosion. Copyright © 2001 John Wiley & Sons, Ltd.
Process‐oriented catchment modelling and multiple‐response validation
Authors: Uhlenbrook S. , Leibundgut Ch.
Published: August 2002

The conceptual rainfall runoff model TAC (tracer‐aided catchment model) has been developed based on the experimental results of tracer hydrological investigations at the mountainous Brugga and Zastler basins (40 and 18·4 km2). The model contains a physically realistic description of the runoff generation, which includes seven unit types each with characteristic dominating runoff generation processes. These processes are conceptualized by different linear and non‐linear reservoir concepts. The model is applied to a period of 3·2 years on a daily time step with good success. In addition, an extensive model validation procedure was executed. Therefore, additional information (i.e. runoff in subbasins and a neighbouring basin, tracer concentrations and calculated runoff components) was used besides the simulated discharge of the basin investigated. This study shows the potential of tracer data for hydrological modelling. On the one hand, they are good tools to investigate the runoff generation processes. This is the basis for developing more realistic conceptualizations of the runoff generation routine. On the other hand, tracer data can serve as multi‐response data to assess and validate a model. Copyright © 2002 John Wiley & Sons, Ltd.
Aspects of weathering and solute acquisition processes controlling chemistry of sub‐Alpine proglacial streams of Garhwal Himalaya, India
Authors: Singh Abhay Kumar , Hasnain S. I.
Published: August 2002

An analytical study of major cations and anions of the proglacial streams of Garhwal Himalaya has been carried out to assess the weathering and geochemical processes in high altitude river basins. Calcium and magnesium are the major cations, and bicarbonate and sulphate are the most dominant anions in these waters. A high correlation among HCO3, Ca and Mg, a relatively high contribution of (Ca+Mg) to the total cations (TZ+) and high (Ca+Mg/Na+K) ratio indicate carbonate weathering could be the primary source of the dissolved ions. Carbonic acid weathering is the major proton‐producing reaction in the Alaknanda River, while in the Bhagirathi River it is the coupled reaction which controls the solute acquisition processes. To know the geochemical factors controlling the chemical nature of water, R‐mode factor analysis on major ion data from Ganga headwater streams has been performed. Factor 1 in the Alaknanda River is explicitly a bicarbonate factor showing strong loading of EC, Ca, Mg, HCO3and TDS. In the Bhagirathi River Factor 1 explains the sulphide dissolution and silicate weathering and Factor 2 explains carbonate weathering. Wide downstream variations are observed in the total dissolved solids (TDS) and total suspended matter (TSM) in the headwater streams of the Ganga. Quartz and feldspar are the common detrital minerals, and kaolinite and illite the common clay minerals in the suspended sediment. Copyright © 2002 John Wiley & Sons, Ltd.
Ethnic and gender bias among Dutch and Turkish children in late childhood: The role of social context
Authors: Verkuyten Maykel , Thijs Jochem
Published: August 2002

In this study, intergroup bias is investigated among Dutch and Turkish children (10–13 years of age) living in the Netherlands. Children indicated their general attitudinal orientations towards boys and girls as well as towards Dutch and Turkish contemporaries. The role of social context was examined in terms of cultural and status differences between ethnic and gender categories, and also in terms of the school situation. Compared to Dutch children, the Turkish children showed less ethnic bias but more gender bias. In addition, boys showed more ethnic bias than girls, with girls indicating more gender bias. Furthermore, Turkish children had higher ethnic identification than did Dutch children, and girls had higher gender identification than boys. Intercultural education was shown to have a positive effect on ethnic bias, and the percentage of Dutch children in the classroom had a negative effect. Neither characteristic had an effect on gender bias. It is argued that the pattern of results is most in agreement with an intergroup perspective in which the role of social context is taken into account. Copyright © 2001 John Wiley & Sons, Ltd.
How specific is the relation between executive function and theory of mind? Contributions of inhibitory control and working memory
Authors: Carlson Stephanie M. , Moses Louis J. , Breton Casey
Published: August 2002

The relation between executive function (EF) and theory of mind (ToM) may involve specific processes of inhibition and/or working memory capacity contributing to ToM, or it might be a reflection of general intellectual ability. To differentiate these alternatives, we administered task batteries measuring inhibitory control (IC), working memory, and ToM, as well as measures of verbal and performance intelligence, to 47 typically developing preschool children. Inhibitory control tasks in which a dominant response needed to be suppressed while a subdominant response was activated (Conflict IC) significantly predicted performance on false belief tasks over and above working memory, the intelligence measures, a simple delay task (Delay IC), and age. In contrast, working memory, Delay IC, and intelligence were not significant in this analysis. Conflict IC, but not Delay IC, was related to working memory. Together, these findings suggest that the combination of inhibition and working memory (as reflected in Conflict IC tasks) may be central to the relation between EF and false belief understanding. Copyright © 2002 John Wiley & Sons, Ltd.
HER‐2/neu–derived peptide epitopes are also recognized by cytotoxic CD3+CD56+ (natural killer T) lymphocytes
Authors: Baxevanis Constantin N. , Gritzapis Angelos D. , Tsitsilonis Ourania E. , Katsoulas Haralabos L. , Papamichail Michael
Published: August 2002

The human HER‐2/neu gene encodes a 185 kDa transmembrane glycoprotein recognized by MHC class I–restricted CTLs. Here, we report that HER‐2/neu peptide CTL epitopes can also be recognized by cytotoxic NK‐T lymphocytes. Unfractionated peptides derived from HLA‐A2+, HER‐2/neu+ tumor cells acid cell extract (ACE), collected from patients with metastatic ovarian cancer, were used as antigen to generate in vitro cytotoxic effectors. ACE was able to elicit from cancer patients' PBMCs both αβTCR+CD3+CD56− and αTCR+CD3+CD56+ (NK‐T) CTLs that lysed ACE‐sensitized T2 cells in an HLA‐A2–restricted manner. The same CTL lines also recognized T2 cells pulsed with HER‐2/neu–derived CTL peptide epitopes, a HER‐2/neu–transfected HLA‐A2+ cell line and autologous tumor cells. αTCR+CD3+CD56+ CTL lines also exhibited NK‐like cytotoxicity against autologous tumor cells. CTL clones were isolated from αTCR+CD3+CD56+ bulk cultures displaying both MHC‐ and non‐MHC–restricted cytotoxicity, thus confirming the dual cytolytic function of such cells. Our data demonstrate that ACE from metastatic ovarian tumors can be used as multiepitope vaccines for generating in vitro, besides classical CTLs, NK‐T cells exerting efficient MHC‐ and non‐MHC–restricted cytotoxicity against autologous tumor targets. Such NK‐T cells expressing dual cytotoxic activity may prove advantageous in cancer immunotherapy. © 2002 Wiley‐Liss, Inc.
PPARγ‐mediated antineoplastic effect of NSAID sulindac on human oral squamous carcinoma cells
Authors: Nikitakis Nikolaos G. , Hebert Carla , Lopes Marcio A. , Reynolds Mark A. , Sauk John J.
Published: August 2002

There is strong evidence that nonsteroidal antiinflammatory drug (NSAID) sulindac may exert a significant antineoplastic effect. The purpose of our study was to explore the effects of sulindac on human oral squamous cell carcinoma (SCCa) cells and to elucidate the underlying molecular mechanisms. The changes that sulindac treatment induced on growth, apoptosis and cell cycle distribution of human oral SCCa cell lines were assessed by cell growth and flow cytometry experiments. Utilizing quantitative RT‐PCR and immunocytochemistry, we determined the effect of sulindac treatment on mRNA and protein expression of different sulindac's targets. Also, PPARγ expression was selectively targeted by antisense oligonucleotide treatment. Both sulfide and sulfone metabolites of sulindac, which differ in the ability to cause COX‐2 inhibition, induced a significant dose‐ and time‐dependent cell growth reduction accompanied by increase in apoptosis without concomitant cell cycle arrest. Sulindac treatment also caused upregulation of the protein and mRNA expression levels of COX‐2 and PPARs. Treatment with antisense PPARγ oligonucleotides abolished sulindac's growth inhibitory effect. Our results are consistent with a significant growth inhibitory effect of NSAID sulindac on human oral SCCa cells, which is mediated, at least partially, through induction of apoptosis. We suggest that upregulation of PPARγ expression and activation may be, at least partially, responsible for sulindac's antiproliferative effect. © 2002 Wiley‐Liss, Inc.
Lifelong vegetarianism and risk of breast cancer: A population‐based case‐control study among South Asian migrant women living in England
Authors: dos Santos Silva Isabel , Mangtani Punam , McCormack Valerie , Bhakta Dee , Sevak Leena , McMichael Anthony J.
Published: August 2002

To investigate the role of lifelong vegetarianism on the aetiology of female breast cancer, we conducted a population‐based case‐control study among South Asian migrant women from the Indian subcontinent resident in England. A total of 240 South Asian breast cancer cases were identified from 2 cancer registries during 1995–1999. For each case, 2 age‐matched South Asian controls were randomly selected from the age‐sex register of the case practice. Lifelong vegetarians had a slight reduction, although not statistically significant, in the odds of breast cancer relative to lifelong meat‐eaters, which persisted after adjustment for socio‐demographic and reproductive variables [odds ratio (OR)=0.77; 95% confidence interval (CI)=0.50–1.18]. Analysis by food group revealed no linear trend in the odds of breast cancer with increasing consumption of meat (p=0.10) but the odds were higher for women in the top 75%. In contrast, there were strong inverse trends in the odds of breast cancer with increasing intake of vegetables (p=0.005), pulses (p=0.007) and fibre [non‐starch polysaccharides, NSP (p=0.02)], with women in the highest 25% of intake of these foods having about 50% of the odds of those in the lowest ones. Adjustment for intake of vegetables and pulses reverted the odds of breast cancer in lifelong vegetarians relative to lifelong meat‐eaters (OR=1.04; 95% CI=0.65–1.68) and attenuated the quartile‐specific estimates for meat intake, whereas the inverse trends in the odds of breast cancer with intake of vegetables and pulses remained after adjustment for type of diet or meat intake. These findings suggest that lifelong vegetarianism may be associated with a reduction in the risk of breast cancer through its association with a higher intake of vegetables and pulses. Although it is not possible to exclude the possibility that lifelong meat abstention may also play a role, the findings provide evidence that a diet rich in vegetables and pulses, such as those typically found in South Asian diets, may be protective against this cancer. © 2002 Wiley‐Liss, Inc.
Circulating enterolactone and prostate cancer risk: A Nordic nested case‐control study
Authors: Stattin Pär , Adlercreutz Herman , Tenkanen Leena , Jellum Egil , Lumme Sonja , Hallmans Göran , Harvei Sverre , Teppo Lyly , Stumpf Katariina , Luostarinen Tapio , Lehtinen Matti , Dillner Joakim , Hakama Matti
Published: August 2002

Enterolactone, a phytoestrogen belonging to the class of lignans, is produced by the intestinal microflora from precursors in plant foods and has been implicated in protection against cancer. We study the effect of enterolactone on the risk of a subsequent diagnosis of prostate cancer. We conducted a longitudinal, nested case‐control study by linkage of 3 biobanks to the cancer registries in Finland, Norway and Sweden, respectively. Enterolactone concentrations were measured by time‐resolved fluoroimmunoassay in serum from 794 men who had a diagnosis of prostate cancer at a mean follow‐up time of 14.2 years after blood collection and among 2,550 control men matched within each cohort for age (±2 years), date of blood collection (±2 months) and county. The median enterolactone concentrations did not differ between case and control subjects in the full study group (8.4 nmol/L [25th–75th percentile = 4.5–15.0] vs. 8.5 nmol/L [25th–75th percentile = 4.3–15.9]), nor in the national groups. Odds ratios of prostate cancer risk estimated by conditional logistic regression for increasing concentrations of enterolactone in quartiles in the full study group were 1.00 (referent), 1.21 (95% confidence interval [CI] = 0.96–1.52), 1.16 (95% CI = 0.91–1.47) and 1.08 (95% CI = 0.83–1.39). The OR estimate for the highest vs. the lowest quartile of enterolactone in separate analyses of the Norwegian, Finnish and Swedish cohort was 1.21 (95% CI = 0.91–1.60), 1.02 (95% CI = 0.59–1.76) and 0.87 (95% CI = 0.45–1.67), respectively. No support for the hypothesis that high circulating enterolactone is protective against prostate cancer was found. © 2002 Wiley‐Liss, Inc.
Reconstructing the Small Area Geography of Mid‐Wales for an Analysis of Population Change 1961–95
Authors: Walford Nigel
Published: August 2002

Reversal of the long‐established trend of rural depopulation during recent decades has countered the continuing decline to which peripheral rural areas of developed countries were condemned in the 1960s. This paper reconstructs the small area geography of Mid‐Wales in order to provide a set of consistent small spatial units for examining net intercensal population and household change since 1961, and for projecting the 1961 community population totals forwards to 1971, 1981 and 1991. This offers the opportunity to consider the usefulness of spatial analysis tools in geographical information systems and small area population projections for population geographers. Analysis of net population change reveals that several communities continued to experience demographic decline despite repopulation overall, and that urban and rural communities had net increases in their household totals irrespective of their history of population change. This analysis provides a context for a survey of households yielding some insights into the processes underlying these demographic changes. The survey provides evidence not only of economic migration, but also of households altering their housing characteristics or household composition in connection with relocating to a rural environment. Copyright © 2001 John Wiley & Sons, Ltd.
The International Dispersal of Pensioners from Affluent Countries
Authors: Warnes Anthony M.
Published: August 2002

This paper examines the distribution of the older beneficiaries of state social security programmes, with particular attention to the UK, the US and Australia. These data have not previously been analysed by a migration researcher, provide a partial source on international retirement moves, and make clear that several processes and types contribute to the international dispersal of a country's retirement population. They show that ‘return’ and ‘family‐joining’ migrations are the predominant form, and that their forms and destinations are changing. The British increasingly select European destinations at the expense of the formerly dominant destinations of Australia, Canada, New Zealand and South Africa. The US continues to be a leading destination for British and German retirees. European data also show that ‘amenity‐seeking’ retirement moves from northern to Mediterranean countries have increased rapidly in recent decades and are growing faster than other types of retirement migration. Social security records also reveal new patterns of return migrations – the number of British pensioners in several Caribbean countries is increasing rapidly, and high shares of Australian overseas migrants are in Mediterranean countries such as Italy, Greece and Malta. Given the paucity of research on these emergent migration flows, the paper concludes by discussing both the prospects for their growth and research priorities. Copyright © 2001 John Wiley & Sons, Ltd.
A technique of object‐adaptive vertex‐based shape coding for MPEG‐4 videos
Authors: Lin Shinfeng D. , Lin Chien‐Chuang , Shie Shih‐Chieh
Published: August 2002

The MPEG‐4 visual standard is the first international standard that allows the transmission of arbitrarily shaped video objects and provides technologies to view, access, and manipulate objects rather than pixels. It addresses the encoding of video objects by shape coding, motion estimation, and texture coding for interactivity, high compression, and scalability. Current binary shape‐coding techniques can be classified into two categories: bitmap based and contour based. O'Connell (1997) proposed an object‐adaptive vertex‐based shape‐coding method to improve the efficiency of shape coding. This method encodes the relative locations of a video object's vertices by adapting the representation to the dynamic range of the relative locations and by exploiting an octant‐based representation for each relative location. We propose an extension of O'Connell's method. Two relative locations of a video object's vertices are grouped and thexpairs andypairs of the locations are encoded, respectively. Simulation results demonstrate that our method outperforms O'Connell's method. © 2001 John Wiley & Sons, Inc. Int J Imaging Syst Technol, 11, 277–282, 2000
Understanding implementation in Early Head Start programs: Implications for policy and practice
Authors: Paulsell Diane , Kisker Ellen Eliason , Love John M. , Raikes Helen H.
Published: August 2002

The primary goal of the National Early Head Start Research and Evaluation Project is to assess program implementation and the quality of key child development services in the study's 17 research programs. The evaluation team developed rating scales based on the Head Start Program Performance Standards and a process for rating key program elements, then synthesized a large amount of information about program implementation and quality into a concise set of ratings. The team used these ratings to examine programs' progress over time, interpret program impacts, and provide feedback to programs and technical assistance providers on implementation strategies. In this article, we present the rating scales and methods developed for assessing implementation and quality, describe the levels of implementation and quality attained four years after programs were funded, and discuss implications for policy and practice. ©2002 Michigan Association for Infant Mental Health.
Riot control agents: pharmacology, toxicology, biochemistry and chemistry
Authors: Olajos Eugene J. , Salem Harry
Published: August 2002

The desired effect of all riot control agents is the temporary disablement of individuals by way of intense irritation of the mucous membranes and skin. Generally, riot control agents can produce acute site‐specific toxicity where sensory irritation occurs. Early riot control agents, namely, chloroacetophenone (CN) and chlorodihydrophenarsazine (DM), have been replaced with ‘safer’ agents such aso‐chlorobenzylidene malononitrile (CS) and oleoresin of capsicum (OC). Riot control agents are safe when used as intended: however, the widespread use of riot control agents raises questions and concerns regarding their health effects and safety. A large margin exists between dosages that produce harassment and dosages likely to cause adverse health effects for modern riot control agents such as CS and dibenz[b,f]1 : 4‐oxazepine (CR). Yet, despite the low toxicity of modern riot control agents, these compounds are not entirely without risk. The risk of toxicity increases with higher exposure levels and prolonged exposure durations. Ocular, pulmonary and dermal injury may occur on exposure to high levels of these substances, and exposure to riot control agents in enclosed spaces may produce significant toxic effects. Reported deaths are few involving riot control agents, and then only under conditions of prolonged exposure and high concentrations. Recently, concern has focused on the deaths resulting from law enforcement use of OC, a riot control agent generally regarded as safe because it is a natural product. As with other xenobiotics, not enough is known concerning the long‐term/chronic effects of riot control agents. Clearly, there is considerable need for additional research to define and delineate the biological and toxicological actions of riot control agents and to illuminate the full health consequences of these compounds as riot control agents. Copyright © 2001 John Wiley & Sons, Ltd.
Effects of mercury vapor inhalation on reactive oxygen species and antioxidant enzymes in rat brain and kidney are minimal
Authors: Goering Peter L. , Morgan Daniel L. , Ali Syed F.
Published: August 2002

Metals are known to induce the formation of reactive oxygen species (ROS) that initiate oxidative stress, an important mechanism of cell injury. The brain is particularly sensitive to oxidative attack because of its high level of unsaturated lipids and high rate of oxidative metabolism. The objective of this study was to determine if elemental mercury (Hg0) vapor inhalation increases ROS production and affects activities or levels of antioxidant‐related biomolecules in the rat brain and kidney. Adult female Sprague‐Dawley rats were exposed for 2 h per day for 11 consecutive days to Hg0 vapor (1, 2, and 4 mg Hg0 m−3). Brain regions (frontal cortex, cerebellum, brain stem) and kidney were assayed for total Hg, ROS and glutathione (GSH) levels, and for enzyme activities of glutathione peroxidase (GPx) and superoxide dismutase (SOD). Marked exposure‐related increases (2500–5600‐fold) in total Hg were detected in the brain regions and in kidney. A statistically significant increase in ROS production (ca. 30% above controls) was observed only in the cortex of rats exposed to 1 mg m−3 Hg vapor, but no significant changes were apparent at other exposures. Although a trend towards increasing ROS production was observed in the kidney, these effects were not statistically significant. Mercury vapor exposure had no significant effects on GSH levels or GPx activity in the three brain regions, however, statistically significant decreases in GSH and GPx activity were detected in the kidneys of rats exposed to 2 mg m−3. Mercury exposure did not cause significant effects on SOD activity in the brain or kidney. The data indicate that oxidative stress and changes in GSH and activities of antioxidant enzymes do not play a major role in Hg0 vapor toxicity in brain and kidney. Published in 2002 by John Wiley & Sons, Ltd.
Toxic effect of single and binary treatments of synthetic and plant‐derived molluscicides against Achatina fulica
Authors: Rao I. G. , Singh D. K.
Published: August 2002

The toxic effect of single and binary treatments of synthetic and plant‐derived molluscicides was studied against the harmful terrestrial snail Achatina fulica. In single treatments, among the synthetic molluscicides Snail Kill and cypermethrin were potent, whereas Cedrus deodara oil was more toxic among molluscicides of plant origin against A. fulica. In binary treatments, a combination of Cedrusdeodara + Alliumsativum was more toxic. The toxicities of these single and binary treatments of synthetic and plant‐derived molluscicides were dose and time dependent. Copyright © 2002 John Wiley & Sons, Ltd.
Cell adhesion peptides alter smooth muscle cell adhesion, proliferation, migration, and matrix protein synthesis on modified surfaces and in polymer scaffolds
Authors: Mann Brenda K. , West Jennifer L.
Published: August 2002

The effects of cell adhesion peptides (RGDS, KQAGDV, VAPG) on vascular smooth muscle cells grown on modified surfaces and in tissue‐engineering scaffolds were examined. Cells were more strongly adhered to surfaces modified with adhesive ligands than to control surfaces (no ligand or a nonadhesive ligand). Cell migration was higher on surfaces with 0.2 nmol/cm2 of adhesive ligand than on control surfaces, but it was lower on surfaces with 2.0 nmol/cm2 of adhesive ligand than it was on control surfaces. Further, cell proliferation was lower on adhesive surfaces than it was on control surfaces, and it decreased as the ligand density increased. Similarly, in the peptide‐grafted hydrogel scaffolds, cell proliferation was lower in scaffolds containing the adhesive peptides than it was in control scaffolds. After 7 days of culture, more collagen per cell was produced in control scaffolds than in scaffolds containing adhesive peptides. In addition, collagen production decreased in the scaffolds as the ligand concentration increased. While modification of a surface or scaffold material with adhesive ligands initially increases cell attachment, it may be necessary to optimize cell adhesion simultaneously with proliferation, migration, and matrix production. © 2002 Wiley Periodicals, Inc., J Biomed Mater Res 60: 86–93, 2002
Perfusion culture of hepatocytes within galactose‐derivatized biodegradable poly(lactide‐co‐glycolide) scaffolds prepared by gas foaming of effervescent salts
Authors: Park Tae Gwan
Published: August 2002

Galactose, a specific ligand for asialoglycoprotein receptor in hepatocytes, was immobilized onto the internal surface of highly porous biodegradable poly(D,L‐lactic‐co‐glycolic acid) scaffolds prepared by gas foaming of effervescent salts. Rat hepatocytes seeded within the scaffolds were cultivated by using a continuous flow and perfusion reactor system. Flow rate of medium circulating through the closed loop bioreactor system was optimized to minimize the extent of cell washout from the scaffold/cell construct while satisfying the oxygen transport rate to the seeded hepatocytes. Using the flow culture system, the scaffolds immobilized with galactose onto its internal surface retained a greater number of hepatocytes than those with unmodified or immobilized with glucose due to specific interactions between seeded hepatocytes and galactose moieties exposed onto the surface of the scaffolds. The perfusion culture system based on galactose‐modified macroporous scaffolds, under optimal flow conditions, resulted in much higher albumin secretion rate, ∼70 pg/cell/day for 7 days, compared to that with glucose modified scaffolds used as a negative control. The enhanced functional activity of hepatocytes seeded within the galactoes modified scaffolds was likely caused by the formation of aggregated hepatocytes within the scaffolds. © 2001 Wiley Periodicals, Inc. J Biomed Mater Res 59: 127–135, 2002
Surface modification of extrasynovial tendon by chemically modified hyaluronic acid coating
Authors: Momose Toshimitsu , Amadio Peter C. , Sun Yu‐Long , Zhao Chunfeng , Zobitz Mark E. , Harrington Jeffrey R. , An Kai‐Nan
Published: August 2002

We investigated a method for chemically binding hyaluronic acid (HA) to extrasynovial tendon and the effect of chemically modified HA on the gliding resistance of tendon. Canine peroneus longus (PL) tendons were immersed into one of three different solutions (saline, 1% HA, or 1% chemically modified HA) for 2 h. The gliding resistance of treated PL tendons was measured at 1, 5, 10, 20, 50, and 100 cycles in a saline bath. After treatment with unmodified HA and chemically modified HA, the gliding resistance of the PL tendons decreased significantly compared with the saline‐treated tendons (p < 0.05), and this effect of the two HA treatments persisted through 10 cycles. For cycles 20–100, the gliding resistance of PL tendons treated with chemically modified HA remained significantly lower than that of tendons treated either with saline or unmodified HA (p < 0.01). The effect of paratenon removal on gliding resistance was neither statistically significant for repetitions beyond 10 cycles, nor was it an independent predictor of gliding resistance, as the effect (higher resistance after paratenon removal) was mainly seen in the saline‐treated tendons. Chemically modified HA‐treated extrasynovial tendons may improve gliding of tendon graft and reduce adhesion postoperatively, compared with traditional grafts. © 2001 Wiley Periodicals, Inc. J Biomed Mater Res 59: 219–224, 2002
Eight common mistakes that business sellers make
Authors: Hooke Jeffrey
Published: August 2002

Selling a business is like swimming through a tank of sharks, says the author. But you can survive and
prosper—if you're a smart seller. © 2002 John Wiley & Sons, Inc.
Identification of transcription factor in the promoter region of rat regucalcin gene: Binding of nuclear factor I‐A1 to TTGGC motif
Authors: Misawa Hiroyuki , Yamaguchi Masayoshi
Published: August 2002

Hepatic nuclear protein has been reported to bind specifically to the TTGGC sequence of the rat regucalcin gene promoter region in stimulating the promoter activity (Misawa and Yamaguchi [2000] Biochem. Biophys. Res. Commun. 279: 275–281). The present study was undertaken to identify transcription factor, which binds to TTGGC motif in the rat regucalcin gene promoter, using the yeast one‐hybrid system. The sequence between −525 and −504, which has been defined as a functional promoter element II‐b, was used as bait to screen a rat liver cDNA library. Two cDNA clones were identified as a nuclear factor I‐A1 (NF1‐A1). The results of gel mobility shift assay and mutation analysis using recombinant NF1‐A1 protein showed that this protein could specifically bind to TTGGC motif of the II‐b oligonucleotide in promoter region. The expression of NF1‐A1 mRNA was found in the liver, kidney, heart, spleen, and brain of rats. This study demonstrates that NF1‐A1 is a transcription factor in stimulating the rat regucalcin gene promoter activity. J. Cell. Biochem. 84: 795–802, 2002. © 2002 Wiley‐Liss, Inc.
Acrylamide disturbs the subcellular distribution of GABAA receptor in brain neurons
Authors: Ho Wen‐Hsin , Wang Seu‐Mei , Yin Hsiang‐Shu
Published: August 2002

Mechanisms underlying the action of acrylamide on neurons were studied by monitoring the expression of GABAA receptor (R) in cultured brain neurons derived from chicken embryos. In situ trypsinization of the neurons and 3H‐flunitrazepam binding assay were employed to examine the subcellular distribution of GABAAR. A 3‐h exposure of the cultured neurons to 10 mM of acrylamide raised reversibly the proportion of intracellular (trypsin‐resistant) 3H‐flunitrazepam binding sites by about 48% and decreased cell surface binding 24% from respective control values, without altering total cellular binding and the affinity of the ligand. Moreover, the acrylamide treatment induced more intense perikaryal immunostaining of GABAAR α subunit proteins than that in control neurons but did not change the total level of cellular α immunostain, in accordance with the binding data. In the cell bodies of acrylamide‐treated neurons, the level of neurofilament‐200 kDa proteins was similar to control, whereas the tubulin protein content was significantly lowered approximately 51% from control, as revealed by quantifying the immunostained cytoskeletal elements. In addition, electron microscopic observations found reductions in the numbers of microtubules and neurofilaments in the perikarya of acrylamide‐treated neurons. As exhibited by the 3H‐leucine and 3H‐monosaccharide incorporation experiments, the exposure to acrylamide inhibited the rate of general protein synthesis in the culture by 21%, while the rate of glycosylation remained unaltered. Furthermore, in situ hybridization analysis showed that acrylamide did not modify the expression of GABAAR α subunit mRNAs. Taken together, these data suggest that acrylamide may downregulate the microtubular system and disintegrate neurofilaments, and thereby block the intracellular transport of GABAAR, resulting in the accumulation of intracellular receptors. J. Cell. Biochem. 85: 561–571, 2002. © 2002 Wiley‐Liss, Inc.
Release of cytokeratin‐18 and ‐19 fragments (TPS and CYFRA 21‐1) into the extracellular space during apoptosis
Authors: Sheard Michael A. , Vojtesek Borek , Simickova Marta , Valik Dalibor
Published: August 2002

Serum fragments of cytokeratins‐18 and ‐19 (measured as TPS and CYFRA 21‐1, respectively) have traditionally been considered as markers of tumor proliferation, although the evidence is scarce for a causative relationship between proliferation and levels of TPS and CYFRA 21‐1. We examined whether apoptosis might produce TPS and CYFRA 21‐1 fragments. MCF‐7 breast cancer cells were treated with mitomycin C or agonistic anti‐CD95 antibody, and levels of TPS and CYFRA 21‐1 in tissue culture supernatants were compared with the frequency of cells exhibiting the following markers of cell death: intracellular cytokeratin‐18 cleavage, surface staining with annexin‐V, propidium iodide uptake, DNA fragmentation. Twenty‐four hours after inducing apoptosis, levels of TPS and CYFRA 21‐1 were elevated ≥ 4‐fold in culture supernatants. Elevations in TPS and CYFRA 21‐1 coincided with apoptosis measured by the first three cell death markers but preceded DNA fragmentation. These mitomycin C‐ and CD95‐mediated elevations were completely inhibited by co‐incubation with the caspase inhibitors Z‐VAD.fmk and Z‐IETD.fmk, respectively. We conclude that TPS and CYFRA 21‐1 can be abundantly released into the extracellular space during the intermediate stage of epithelial cell apoptosis. J. Cell. Biochem. 85: 670–677, 2002. © 2002 Wiley‐Liss, Inc.
Fibromodulin is expressed by both chondrocytes and osteoblasts during fetal bone development
Authors: Gori Francesca , Schipani Ernestina , Demay Marie B.
Published: August 2002

Fibromodulin, a keratan‐sulfate proteoglycan, was first isolated in articular cartilage and tendons. We have identified fibromodulin as a gene regulated during BMP‐2‐induced differentiation of a mouse prechondroblastic cell line. Because expression of fibromodulin during endochondral bone formation has not been studied, we examined whether selected cells of the chondrocytic and osteoblastic lineage expressed fibromodulin. Fibromodulin mRNA was detected in conditionally immortalized murine bone marrow stromal cells, osteoblasts, and growth plate chondrocytes, as well as in primary murine calvarial osteoblasts. We, therefore, investigated the temporo‐spatial expression of fibromodulin in vivo during endochondral bone formation by in situ hybridization. Fibromodulin was first detected at 15.5 days post coitus (dpc) in the perichondrium and proliferating chondrocytes. Fibromodulin mRNA was also detected at 15.5 dpc in the bone collar and periosteum. At later time points fibromodulin was expressed in the primary spongiosa and the endosteum. To determine whether fibromodulin was expressed during intramembranous bone formation as well, in situ hybridization was performed on calvariae. Fibromodulin mRNA was present in calvarial osteoblasts from 15.5 dpc. These results demonstrate that fibromodulin is developmentally expressed in cartilage and bone cells during endochondral and intramembranous ossification. These findings suggest that this extracellular matrix protein plays a role in both endochondral and intramembranous bone formation. J. Cell. Biochem. 82: 46–57, 2001. © 2001 Wiley‐Liss, Inc.
Inducible expression of the α2‐macroglobulin signaling receptor in response to antigenic stimulation: A study of second messenger generation
Authors: Bhattacharjee Gourab , Misra Uma K. , Gawdi Govind , Cianciolo George , Pizzo Salvatore V.
Published: August 2002

Thioglycollate (TG)‐elicited murine, peritoneal macrophages express two receptors for activated forms of the proteinase inhibitor α2‐macroglobulin (α2M*)—namely, the low density lipoprotein receptor‐related protein (LRP) and the α2M signaling receptor (α2MSR). We now report that resident peritoneal macrophages express only 400 ± 50 α2MSR receptors/cell compared to 5000 ± 500 receptor/TG‐elicited macrophage. By contrast, LRP expression is only 2–2.5‐fold greater on elicited cells. The low level of α2MSR expression by resident cells is insufficient to trigger signal transduction in contrast to TG‐elicited cells which when exposed to α2M* demonstrate a rapid rise in inositol 1,4,5‐trisphosphate and a concomitant increase in cytosolic free Ca2+. We then studied a variety of preparations injected subcutaneously for their ability to upregulate α2MSR. Macroaggregated bovine serum albumin (macroBSA) injection upregulated α2MSR and triggered signaling responses by splenic macrophages. Nonaggregated BSA injection alone or in the presence of alum, by contrast, did not alter α2MSR expression. Recombivax (hepatitis B antigen adsorbed to alum) injection also upregulated α2MSR on splenic macrophages while the alum carrier had no effect. We conclude that macrophage α2M* receptors are inducible and their expression may be regulated, in part, by potential antigens. J. Cell. Biochem. 82: 260–270, 2001. © 2001 Wiley‐Liss, Inc.
Transfer of proα2(I) cDNA into cells of a murine model of human Osteogenesis Imperfecta restores synthesis of type I collagen comprised of α1(I) and α2(I) heterotrimers in vitro and in vivo
Authors: Niyibizi Christopher , Smith Patrick , Mi Zhibao , Phillips Charlotte L. , Robbins Paul
Published: August 2002

The oim mouse is a model of human Osteogenesis Imperfecta (OI) that has deficient synthesis of proα2(I) chains. Cells isolated from oim mice synthesize α1(I) collagen homotrimers that accumulate in tissues. To explore the feasibility of gene therapy for OI, a murine proα2(I) cDNA was inserted into an adenovirus vector and transferred into bone marrow stromal cells isolated from oim mice femurs. The murine cDNA under the control of the cytomegalovirus early promoter was expressed by the transduced cells. Analysis of the collagens synthesized by the transduced cells demonstrated that the cells synthesized stable type I collagen comprised of α1(I) and α2(I) heterotrimers in the correct ratio of 2:1. The collagen was efficiently secreted and also the cells retained the osteogenic potential as indicated by the expression of alkaline phosphatase activity when the transduced cells were treated with recombinant human bone morphogenetic protein 2. Injection of the virus carrying the murine proα2(I) cDNA into oim skin demonstrated synthesis of type I collagen comprised of α1 and α2 chains at the injection site. These preliminary data demonstrate that collagen genes can be transferred into bone marrow stromal cells as well as fibroblasts in vivo and that the genes are efficiently expressed. These data encourage further studies in gene replacement for some forms of OI and use of bone marrow stromal cells as vehicles to deliver therapeutic genes to bone. © 2001 Wiley‐Liss, Inc.
Ab initio crystal structure predictions for flexible hydrogen‐bonded molecules. Part II. Accurate energy minimization
Authors: van Eijck Bouke P. , Mooij Wijnand T. M. , Kroon Jan
Published: August 2002

A method is described to perform ab initio energy minimization for crystals of flexible molecules. The intramolecular energies and forces are obtained directly from ab initio calculations, whereas the intermolecular contributions follow from a potential that had been parameterized earlier on highly accurate quantum‐chemical calculations. Glycol and glycerol were studied exhaustively as prototypes. Lists of hypothetical crystal structures were generated using an empirical force field, after which ab initio energy minimizations were performed for a few hundreds of these. The experimental crystal structures were found among the structures with lowest energy, provided that sufficiently large basis sets were used. Moreover, their crystal geometries were well reproduced. This approach enables a systematic comparison between the merits of force fields at various levels of sophistication. © 2001 John Wiley & Sons, Inc. J Comput Chem 22: 805–815, 2001