bluuebunny/crossref_metadata_2025_split huggingface dataset:
Tracer properties of eroded sediment and source material
Authors: Motha J. A. , Wallbrink P. J. , Hairsine P. B. , Grayson R. B. 
Published: October 2002

AbstractThis paper examines the conservativeness of tracers through the sediment generation process. This is done by comparing a selection of tracer properties of sediment eroded from large plots by simulated rainfall, with the corresponding properties of the source materials within the plots. Sediment was generated using three simulated rainfall events for each of five selected erosion source types in the Tarago catchment, Victoria, Australia. As there were particle size and organic content differences between the source material and the generated sediment, the measured tracer properties of the source material were corrected for these differences. The possible role of analytical errors in this investigation was also addressed. The geochemical property, concentration of Fe2O3, was not conservative for any of the process sources investigated. Concentration of Al2O3 was not conservative for three of the four process sources investigated, and the sum of molecular proportions of CaO**, Na2O, K2O and Al2O3 was not conservative for two of the four process sources investigated. Mineral magnetic properties, IRM850 and χ were also found to be not conservative, although this may be the result of the complex relationship between particle size and mineral magnetic properties not being adequately accommodated in this analysis. The radionuclide tracers, 137Cs and 210Pbex, were found to be conservative through the sediment generation process. Copyright © 2002 John Wiley & Sons, Ltd.
Estimation of baseflow residence times in watersheds from the runoff hydrograph recession: method and application in the Neversink watershed, Catskill Mountains, New York
Authors: Vitvar Tomas , Burns Douglas A. , Lawrence Gregory B. , McDonnell Jeffrey J. , Wolock David M. 
Published: October 2002

AbstractA method for estimation of mean baseflow residence time in watersheds from hydrograph runoff recession characteristics was developed. Runoff recession characteristics were computed for the period 1993–96 in the 2 km2 Winnisook watershed, Catskill Mountains, southeastern New York, and were used to derive mean values of subsurface hydraulic conductivity and the storage coefficient. These values were then used to estimate the mean baseflow residence time from an expression of the soil contact time, based on watershed soil and topographic characteristics. For comparison, mean baseflow residence times were calculated for the same period of time through the traditional convolution integral approach, which relates rainfall δ18O to δ18O values in streamflow. Our computed mean baseflow residence time was 9 months by both methods. These results indicate that baseflow residence time can be calculated accurately using recession analysis, and the method is less expensive than using environmental and/or artificial tracers. Published in 2002 by John Wiley & Sons, Ltd.
Refined conceptualization of TOPMODEL for shallow subsurface flows
Authors: Walter M. Todd , Steenhuis Tammo S. , Mehta Vishal K. , Thongs Dominique , Zion Mark , Schneiderman Elliot 
Published: October 2002

AbstractThe TOPMODEL framework was used to derive expressions that account for saturated and unsaturated flow through shallow soil on a hillslope. The resulting equations were the basis for a shallow‐soil TOPMODEL (STOPMODEL). The common TOPMODEL theory implicitly assumes a water table below the entire watershed and this does not conceptually apply to systems hydrologically controlled by shallow interflow of perched groundwater. STOPMODEL provides an approach for extending TOPMODEL's conceptualization to apply to shallow, interflow‐driven watersheds by using soil moisture deficit instead of water table depth as the state variable. Deriving STOPMODEL by using a hydraulic conductivity function that changes exponentially with soil moisture content results in equations that look very similar to those commonly associated with TOPMODEL. This alternative way of conceptualizing TOPMODEL makes the modelling approach available to researchers, planners, and engineers who work in areas where TOPMODEL was previously believed to be unsuited, such as the New York City Watershed in the Catskills region of New York State. Copyright © 2002 John Wiley & Sons, Ltd.
High‐resolution numerical modelling of three‐dimensional flows over complex river bed topography
Authors: Lane S. N. , Hardy R. J. , Elliott L. , Ingham D. B. 
Published: October 2002

AbstractThis paper describes preliminary results from a method for the treatment of complex bed topography for the understanding of three‐dimensional flow processes. It develops an established porosity‐based method and couples it to high‐resolution bed topographical data acquired using digital photogrammetry. The results provide quantitative data on flow processes that match and perhaps exceed current measurement capabilities, and so raise difficult questions for model validation. However, the detailed flow fields provided by the method allow us to develop current models for flow–form interactions in gravel‐bed rivers. Of most importance, the method will allow us to enhance significantly the application of computational fluid dynamics to complex river bed morphology, for large eddy simulation, roughness parameterization, sediment entrainment and deposition studies, and understanding interactions between flow and vegetation in relation to conveyance studies. Copyright © 2002 John Wiley & Sons, Ltd.
Geographic differences in invasive and in situ breast cancer incidence according to precise geographic coordinates, Connecticut, 1991–95
Authors: Gregorio David I. , Kulldorff Martin , Barry Leah , Samociuk Holly 
Published: October 2002

AbstractTo evaluate geographical variation of invasive and in situ breast cancer incidence rates using precise geographical coordinates for place of residence at diagnosis, latitude‐longitude coordinates pertaining to 10,601 invasive and 1,814 in situ breast cancers for Connecticut women, 1991–95, were linked to US Census information on the 2,905State census block groups. A spatial scan statistic was used to detect geographic excess or deficits in incidence and test the statistical significance of results, without prior assumptions about the size or location of such areas. The age adjusted invasive cancer incidence rate was 165.3/100,000 women/year. The spatial scan statistic identified 3 places with significantly low incidence rates and 4 places where rates were significantly high. The most probable location of low incidence was rural northeastern Connecticut where risk of disease, relative to elsewhere around the state, was 0.70 (p = 0.0001); the most probable place of elevated incidence was north central Connecticut where a relative risk of 1.34 (p = 0.002) was observed. Incidence of in situ disease was estimated to be significantly high for north central Connecticut (RR = 1.84; p = 0.0001). Geographic differences of invasive and in situ breast cancer incidence were observed. Examining cancer events at the lowest available level of data aggregation is beneficial in highlighting localized rate variations. Such information may enable public health officials to target additional resources for promoting breast cancer screening to specific locations. © 2002 Wiley‐Liss, Inc.
Involvement of human heat shock protein 90α in nicotine‐induced apoptosis
Authors: Wu Yu‐ping , Kita Kazuko , Suzuki Nobuo 
Published: October 2002

AbstractThere have been conflicting reports of the apoptotic effects of nicotine on human cells and those studies reporting nicotine‐induced apoptosis have not unequivocally clarified the molecular mechanisms underlying the effect. However, we found here that human RSa cells, established from embryonic fibroblastic cells doubly infected with Rous sarcoma virus and Simian virus 40, underwent apoptosis when cultured with medium containing 0.06–0.6 μM nicotine. The apoptosis was assessed by cellular DNA fragmentation and caspase‐3 protease activation. Viability of RSa cells was reduced by nicotine treatment, as analyzed by MTT assay and the reduction was lessened by combination treatment with a caspase‐3 inhibitor, acetyl‐L‐aspartyl‐L‐glutamyl‐L‐valyl‐L‐aspart‐1‐al (Ac‐DEVD‐CHO). Levels of expression of heat shock protein 90α (Hsp90α) were found to be increased 20 min after the nicotine treatment, as analyzed by polymerase chain reaction‐based mRNA differential display after Northern blotting analysis of mRNA amounts. Cellular contents of Hsp90α were furthermore increased in the nicotine‐treated RSa cells, as quantitated by Western immunoblot analysis. By contrast, in RSa cells treated with nicotine in combination with geldanamycin (GA), an inhibitor of Hsp90α function, DNA fragmentation was not detected and caspase‐3 protease activity levels were the same as those of mock‐treated cells. Nicotine‐induced caspase‐3 activation and Hsp90α expression, as well as suppression of the induction by GA, were also observed in a xeroderma pigmentosum patient‐derived cell line, XP2OS cells. Thus, it was suggested that nicotine induces apoptosis, possibly via Hsp90α expression, in human cells tested. © 2002 Wiley‐Liss, Inc.
Extremely potent, rapid and costimulation‐independent cytotoxic T‐cell response against lymphoma cells catalyzed by a single‐chain bispecific antibody
Authors: Dreier Torsten , Lorenczewski Grit , Brandl Christian , Hoffmann Patrick , Syring Uwe , Hanakam Frank , Kufer Peter , Riethmuller Gert , Bargou Ralf , Baeuerle Patrick A. 
Published: October 2002

AbstractA recent study reported on an anti‐CD19/anti‐CD3 single‐chain bispecific antibody (bscCD19xCD3) exhibiting high activity against human B lymphoma cell lines (Löffler et al., Blood 2000;95:2098–103). In the present study, we have explored in detail the in vitro efficacy, T‐cell donor variability, binding characteristics, specificity, kinetics and interleukin‐2 (IL‐2) dependence of bscCD19xCD3. We found that a majority of human donor T cells tested (n = 86) gave half‐maximal B‐lymphoma cell lysis (ED50) within a range of 10–50 pg/ml bscCD19xCD3, corresponding to sub‐picomolar concentrations of the bispecific antibody. Under identical experimental conditions, the anti‐CD20 monoclonal antibody rituximab had an at least 100,000‐fold lower in vitro efficacy. The extreme potency of bscCD19xCD3 was in sharp contrast to the relatively low affinity of the anti‐CD3 and anti‐CD19 single‐chain Fv portions in KD ranges of 10−7 and 10−9 M, respectively. Cell lysis by bscCD19xCD3 was predominantly mediated by the population of CD8/CD45RO‐positive T cells. Both immortalized CD4‐ and CD8‐positive human T‐cell clones were highly active effector cells as well. Cell lysis by bscCD19xCD3 was rapid and specific. The respective parental monoclonal antibodies inhibited cell lysis and CD19‐negative cells were not harmed by T cells in the presence of high amounts of bscCD19xCD3. The potent T‐cell stimulus IL‐2 could not markedly augment the activity of bscCD19xCD3‐stimulated T cells. In conclusion, bscCD19xCD3 could redirect unstimulated cytotoxic T cells against CD19‐positive cells in an unexpectedly potent, rapid and specific fashion. © 2002 Wiley‐Liss, Inc.
Cellular effects of CPT‐11 on colon carcinoma cells: Dependence on p53 and hMLH1 status
Authors: Magrini Roberta , Bhonde Mandar R. , Hanski Marie‐Luise , Notter Michael , Scherübl Hans , Boland C. Richard , Zeitz Martin , Hanski Christoph 
Published: October 2002

AbstractIrinotecan (CPT‐11), a recently introduced component of a standard chemotherapy for colorectal cancer, induces in colon cancer cell lines in vitro cell cycle arrest and apoptosis. Since sporadic colon carcinomas exhibit in 50–60% mutations in the p53 gene and in 10–15% an MSI phenotype due in the great majority of the cases to hMLH1 inactivation, we investigated how these lesions influence the cellular effects of CPT‐11 by using colorectal carcinoma cell line HCT116 (which has the genotype p53+/+,hMLH1−) and 2 derivative cell lines with the genotypes p53+/+,hMLH1+ and p53−/−,hMLH1−. CPT‐11 treatment induced G2/M arrest in all 3 cell lines within 48 hr. In the p53+/+,hMLH1+ cell line, G2/M arrest was maintained for at least 12 days. There was little concomitant apoptosis, but this was enhanced when the hMLH1 protein was absent. This enhanced apoptosis was accompanied by a shorter duration of the G2/M arrest than in the hMLH1+ cell line. Partial abrogation of G2/M arrest by caffeine enhanced apoptosis in both hMLH1+ and hMLH1− cells. By contrast, in the p53−/− cell line, the G2/M arrest was terminated within 4 days. Termination of the G2/M arrest was accompanied by a high level of apoptosis detectable through poly(ADP‐ribose)polymerase (PARP) cleavage, DNA fragmentation and by the appearance of cells with a DNA content <2N. The triggering of G2/M arrest was accompanied in the 3 cell lines by a transient phosphorylation of cdc‐2, while the maintenance of the arrest in the p53+/+ cell lines was accompanied by the overexpression of p53 and p21 proteins and, consequently, by the inhibition of cdc‐2 kinase activity. These data indicate that: (i) CPT‐11 induces long‐term arrest in p53+/+ cells and a short‐term arrest followed by apoptosis in p53−/− cells; (ii) triggering of the arrest is p53 independent and is associated with a brief increase of phosphorylation of cdc‐2, while the p53‐dependent maintenance of G2/M arrest is associated with the inhibition of cdc‐2 kinase activity by p21; and (iii) lack of hMLH1 protein enhances CPT‐11‐induced apoptosis. These results may be useful for designing rational therapies dependent on the p53 and mismatch‐repair status in the tumor. © 2002 Wiley‐Liss, Inc.
TP53mutations in breast cancer tumors of patients from Rio de Janeiro, Brazil: Association with risk factors and tumor characteristics
Authors: Simão Tatiana A. , Ribeiro Fabiana S. , Amorim Lídia M. F. , Albano Rodolpho M. , Andrada‐Serpa Maria J. , Cardoso Lúis E. B. , Mendonça Gulnar A. S , de Moura‐Gallo Cláudia V. 
Published: October 2002

AbstractSomatic mutations in theTP53gene are the most frequently observed genetic alterations in human malignancies, including breast cancer, which is one of the leading causes of death among women in Brazil. In our study, we determined the frequency and the pattern ofTP53mutations in malignant breast tumors from 120 patients living in Rio de Janeiro, Brazil.TP53mutations were found in 20% of the tumors, which contained a diversity of mutation types: missense (62.5%), nonsense (8.3%), silent (4.2%), intronic (12.5%), insertion (4.2%) and deletion (8.3%). Of a total of 15 missense mutations, 4 were observed at Arg248 and 2 at Cys242, which are directly involved in DNA binding and in zinc binding, respectively. A subgroup of 51 patients was analyzed with respect to the relation between the presence ofTP53mutations and classical risk factors and with tumor and patient characteristics. For this analysis, we used logistic regression and, in order to obtain more precise confidence intervals, they were recalculated using a bootstrap resampling technique. Our results demonstrate that these mutations are not statistically associated with the risk factors or the patients' characteristics. However, the presence ofTP53mutations is strongly associated with the aggressiveness of the tumors, measured by Elston classification (OR = 11.97 and 95% CI of 2.24–307.05). This finding is in agreement with previous studies, which report the presence ofTP53mutations in tumors with poor prognosis. This correlation between tumor aggressiveness andTP53mutations could be a crucial variable for the treatment and prognosis of breast cancer. © 2002 Wiley‐Liss, Inc.
Affect expression in prenatally psychotropic exposed and nonexposed mother–infant dyads
Authors: Reebye Pratibha N. , Morison Sara J. , Panikkar Hira , Misri Shaila , Grunau Ruth E. 
Published: October 2002

AbstractThis prospective study examined infant, maternal, and dyadic affective profiles at three months postpartum in infant–mother dyads that were exposed to psychotropic medications in utero compared with nonexposed control dyads. Control dyads of nondepressed mothers and their infants showed many similarities in affect expression with mother–infant dyads who were exposed to selective serotonin reuptake inhibitors (SSRIs) alone for treatment of maternal depression. In contrast, mothers who received SSRIs and Rivotril (Benzodiazepine derivative) for treatment of depression and anxiety expressed both positive and negative affect towards their infants. Clinical implications regarding use of psychotropic medications such as SSRIs alone or in combination with other drugs for treatment of maternal anxiety and depression during pregnancy are discussed. Clinicians should be aware of the possible differential response in maternal–infant interaction in a mixed diagnosis group (i.e., depression and anxiety) regarding infant temperament, possibly suggesting latent behavioral teratogenicity with psychotropics. ©2002 Michigan Association for Infant Mental Health.
Mineral deficiency and the use of the FETAX bioassay to study environmental teratogens
Authors: Garber Eric A. E. 
Published: October 2002

AbstractThe Frog Embryo Teratogenesis Assay: Xenopus (FETAX) bioassay has been employed extensively to screen compounds for teratogenic activity. Recent laboratory studies have indicated that low potassium concentrations retard Xenopus laevis development. The effects of varying concentrations of minerals on Xenopus laevis embryo length and development were examined to determine the utility of the FETAX bioassay in the study of environmental teratogens. Water samples collected from 18 wetlands in Minnesota and North Dakota correlated with low mineral levels, causing delayed embryonic development in the FETAX bioassay. When the concentration of sodium or potassium was <5 ppm, Xenopus laevis development was delayed. As a result, it was difficult to assess teratogenic activity after 96 h of incubation. Furthermore, the length of the embryos—an indication of development—paralleled changes in mineral composition. Comparisons between different wetlands based on changes in one specific mineral were not possible due to a synergism between various minerals. If the concentration of sodium and/or potassium was <5 ppm but ≥2 ppm, extension of the FETAX bioassay to 120 h allowed organogenesis to proceed through stage 46, as required for scoring in accordance with ASTM guidelines for the FETAX bioassay. In those cases in which the concentration of sodium and/or potassium were <2 ppm, the embryos could not develop to stage 46 within 120 h and the FETAX bioassay was not suitable for detecting teratogenic activity. Published in 2002 by John Wiley & Sons, Ltd.
Assessment of genome damage in a population of Croatian workers employed in pesticide production by chromosomal aberration analysis, micronucleus assay and Comet assay
Authors: Garaj‐Vrhovac Vera , Zeljezic Davor 
Published: October 2002

AbstractThe widespread use of pesticides suggests that the evaluation of their genotoxicity should be extended using the different assays available. In the present study we used two standard cytogenetic methods (chromosomal aberration analysis and micronucleus assay) and the Comet assay as a relatively new and powerful technique. The study included 10 workers occupationally exposed to a complex mixture of pesticides (atrazine, alachlor, cyanazine, 2,4‐dichlorophenoxyacetic acid, malathion) during their production and 20 control subjects with no history of exposure to any physical or chemical agents. For the chromosomal aberration analysis, whole blood was cultivated for 48 h, whereas for the micronucleus assay, whole blood was cultivated for 72 h. For the comet assay whole blood was embedded in agarose on a microscope slide, lysed with detergent, denaturated and subjected to alkaline electrophoresis. Damage to DNA was evaluated by measuring tail length and calculating the tail moment. A significantly increased number of chromatid and chromosome breaks, as well as the presence of dicentric chromosomes and chromatid exchanges in exposed subjects compared with control subjects (P < 0.05), was found. There was also a statistically significant difference in frequency and distribution of micronuclei between the two groups examined. In the exposed subjects the Comet assay showed a statistically significant (P < 0.001) increase in DNA migration. Results suggest that long‐term occupational exposure to pesticides could cause genome damage in somatic cells and therefore may represent a potential hazard to human health. Copyright © 2002 John Wiley & Sons, Ltd.
Mechanisms of magnesium‐stimulated adhesion of osteoblastic cells to commonly used orthopaedic implants
Authors: Zreiqat H. , Howlett C. R. , Zannettino A. , Evans P. , Schulze‐Tanzil G. , Knabe C. , Shakibaei M. 
Published: October 2002

AbstractPoor cell adhesion to orthopaedic and dental implants may result in implant failure. Cellular adhesion to biomaterial surfaces primarily is mediated by integrins, which act as signal transduction and adhesion proteins. Because integrin function depends on divalent cations, we investigated the effect of magnesium ions modified bioceramic substrata (Al2O3‐Mg2+) on human bone‐derived cell (HBDC) adhesion, integrin expression, and activation of intracellular signalling molecules. Immunohistochemistry, flow cytometry, cell adhesion, cell adhesion blocking, and Western blotting assays were used. Our findings demonstrated that adhesion of HBDC to Al2O3‐Mg2+ was increased compared to on the Mg2+‐free Al2O3. Furthermore, HBDC adhesion decreased significantly when the fibronectin receptor α5β1‐ and β1‐integrins were blocked by functional blocking antibodies. HBDC grown on the Mg2+‐modified bioceramic expressed significantly enhanced levels of β1‐, α5β1‐, and α3β1‐integrins receptors compared to those grown on the native unmodified Al2O3. Tyrosine phosphorylation of intracellular integrin‐dependent signalling proteins as well as the expression of key signalling protein Shc isoforms (p46, p52, p66), focal adhesion kinase, and extracellular matrix protein collagen type I were significantly enhanced when HBDC were grown on Al2O3‐Mg2+ compared to the native Al2O3. We conclude that cell adhesion to biomaterial surfaces is probably mediated by α5β1‐ and β1‐integrin. Cation‐promoted cell adhesion depends on 5β1‐ and β1‐integrins associated signal transduction pathways involving the key signalling protein Shc and results also in enhanced gene expression of extracellular matrix proteins. Therefore, Mg2+ supplementation of bioceramic substrata may be a promising way to improve integration of implants in orthopaedic and dental surgery. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res 62: 175–184, 2002