bluuebunny/crossref_metadata_2025_split huggingface dataset:
Antiplatelet agents for prevention of pre-eclampsia and its consequences: a systematic review and individual patient data meta-analysis
Authors:   The Perinatal Antiplatelet Review of International Studies (PARIS) Collaboration Steering Group on behalf of the PARIS Collaboration,   The PARIS Collaboration
Published: March 2005

Abstract

Background
There is now good evidence that antiplatelet agents (principally low dose aspirin) prevent pre-eclampsia, a leading cause of morbidity and mortality for pregnant women and their babies. A Cochrane Review identified moderate, but clinically important, reductions in the relative risks of pre-eclampsia (19%), preterm birth (7%) and perinatal mortality (16%) in women allocated antiplatelets, rather than placebo or no antiplatelet.
Uncertainty remains, however, about whether some women (in terms of risk) benefit more than others, what dose of aspirin is best and when in pregnancy treatment should ideally start. Rather than undertake new trials, the best way to answer these questions is to utilise existing individual patient data from women enrolled in each trial.

Methods/Design
Systematic review with meta-analysis based on individual patient data. This involves the central collection, validation and re-analysis of thoroughly checked data from individual women in all the available randomised trials.
The objective is to confirm that antiplatelet agents, given during pregnancy, will reduce the incidence of pre-eclampsia. The review will then determine the size of this effect, and whether antiplatelets delay the onset of pre-eclampsia or its impact on important outcomes for women and their babies. It will also explore whether the effect of antiplatelets differs by womens' risk profile; when commenced during pregnancy; and/or by dose.

Discussion
The PARIS (Perinatal Antiplatelet Review of International Studies) Collaboration has been formed to undertake the review. This will be the first individual patient data review in the perinatal field. Final results should be available by 2006–7.
Effects of exposure to a combination of zinc- and lead-spiked sediments on mouthpart development and growth in Chironomus tentans
Authors: Martinez Edward A. , Moore Barry C , Schaumloffel John , Dasgupta Nairanjana 
Published: March 2005

Abstract
Exposures to either zinc or lead in contaminated sediments have been shown to induce characteristic deformities in larval chironomids. This study examined the effects of exposure to lead and zinc in combination on Chironomus tentans larvae. Proportions of mouthpart deformities in populations of larvae reared in sediments containing nominal combinations of lead and zinc were tested for additive, synergistic, and antagonistic interactions using logistic regression. Metal body burdens, body size measurements, and survival were used to evaluate toxicity and developmental impacts. Results demonstrate zinc and lead mixtures produce fewer deformities than the individual metal, so their interaction may be characterized as antagonistic. However, exposure to the metal mixtures also caused delayed development and failure to hatch. The apparent decline in deformities may be an artifact of higher mortalities or developmental effects. This research provides better understanding of some of the problems and considerations for use of chironomid population deformity proportions in bioassessments for sediment metal contamination.
Toxicological profiling of sediments using in vitro bioassays, with emphasis on endocrine disruption
Authors: Houtman Corine J. , Cenijn Peter H. , Hamers Timo , Lamoree Marja H. , Legler Juliette , Murk Albertinka J. , Brouwer Abraham 
Published: March 2005

Abstract
In vitro bioassays are valuable tools for screening environmental samples for the presence of bioactive (e.g., endocrine-disrupting) compounds. They can be used to direct chemical analysis of active compounds in toxicity identification and evaluation (TIE) approaches. In the present study, five in vitro bioassays were used to profile toxic potencies in sediments, with emphasis on endocrine disruption. Nonpolar total and acid-treated stable extracts of sediments from 15 locations in the Rhine Meuse estuary area in The Netherlands were assessed. Dioxin-like and estrogenic activities (using dioxin-responsive chemical-activated luciferase gene expression [DR-CALUX] and estrogen-responsive chemical-activated luciferase gene expression [ER-CALUX] assays) as well as genotoxicity (UMU test) and nonspecific toxic potency (Vibrio fischeri assay) were observed in sediment extracts. For the first time, to our knowledge, in vitro displacement of thyroid hormone thyroxine (T4) from the thyroid hormone transport protein thransthyretin by sediment extracts was observed, indicating the presence of compounds potentially able to disrupt T4 plasma transport processes. Antiestrogenic activity was also observed in sediment. The present study showed the occurrence of endocrine-disrupting potencies in sediments from the Dutch delta and the suitability of the ER- and DR-CALUX bioassays to direct endocrine-disruption TIE studies.
Increased kidney, liver, and testicular cell death after chronic exposure to 17α-ethinylestradiol in medaka (Oryzias latipes)
Authors: Weber Lynn P. , Balch Gordon C. , Metcalfe Chris D. , Janz David M. 
Published: March 2005

Abstract
Sublethal effects observed in fish exposed to environmental estrogens may be mediated via stimulation of cell death. To investigate whether cell death is induced in fish after chronic exposure to estrogenic chemicals, Japanese medaka (Oryzias latipes) were exposed from hatch until sexual maturity to 10 ng/L 17α-ethinylestradiol (EE2) or acetone solvent (control). Cell death was evaluated in blinded histological sections of whole medaka using terminal dideoxynucleotidyl-mediated dUTP nick end-labeling (TUNEL), which labels nuclei of cells containing apoptotic or necrotic (fragmented) DNA. The major impact of EE2 exposure in both male and female medaka was to significantly increase the number of TUNEL-positive hepatocytes and kidney tubule cells compared to control. Cell morphology was consistent with apoptosis in the liver and cloudy swelling or necrosis in the tubule cells. The number of TUNEL-positive interstitial (hematopoietic) and glomerular cells was significantly greater in the kidneys of EE2-exposed male, but not female, medaka. The EE2 exposure also significantly increased the number of TUNEL-positive testicular cells in medaka compared to corresponding controls, namely Leydig cells, Sertoli cells, spermatocytes, and spermatids. In medaka with gonadal intersex, areas of fibrosis and areas containing female gonadal cells were relatively unstained with TUNEL. No effect of EE2 exposure on the number of TUNEL-positive ovarian somatic cells or on the rate of female ovarian follicle atresia was found. These results suggest that chronic exposure to EE2 in medaka is hepatotoxic and nephrotoxic in both sexes, whereas gonadal toxicity is specific to males.
An assessment of the bioaccumulation of estrone in Daphnia magna
Authors: Gomes Rachel L. , Deacon Hannah E. , Lai Ka M. , Birkett Jason W. , Scrimshaw Mark D. , Lester John N. 
Published: March 2005

Abstract
The bioaccumulation of estrone by Daphnia magna was determined. Direct uptake via the aqueous medium occurred within the first 16 h. A bioconcentration factor of 228 was established over all temporal periods. Ingestion via Chlorella vulgaris gave a partitioning factor of 24, which may approximate to a biomagnification factor assuming steady state conditions. These preliminary results indicate that the partitioning to Daphnia magna via the food source, C. vulgaris is less significant than bioconcentration.
Effect of 3,4,3′,4′-tetrachlorobiphenyl on the reworking behavior of Lumbriculus variegatus exposed to contaminated sediment
Authors: Landrum Peter F. , Leppänen Matti , Robinson Sander D. , Gossiaux Duane C. , Burton G. Allen , Greenberg Marc , Kukkonen Jussi V. K. , Eadie Brian J. , Lansing Margaret B. 
Published: March 2005

Abstract
The reworking response (bioturbation) of the oligochaete Lumbriculus variegatus was measured by following the burial rate and spread of a 137Cs marker layer translating worm activity into a biological burial rate (Wb) and a biological diffusion rate constant (Db) for surficial sediment mixing. Reworking was measured at 10 and 22°C in two sediments: a reference site sediment dosed with 3,4,3′,4′-tetrachlorobiphenyl (TCBP) and a field-collected sediment from a polychlorinated biphenyl (PCB)-contaminated site in Dicks Creek (DCC, Middletown, OH, USA). The body residue associated with response to TCBP also was determined. Reduction in the temperature from 22 to 10°C reduced both Wb and Db by a factor of approximately two. The internal TCBP concentration to reduce the Wb by 50% was 96 nmol/g (95% CI 45–225 nmol/g) and 124 nmol/g (40–547 nmol/g) (28 and 36 μg/g) wet weight at 22 and 10°C, respectively, and was independent of temperature. The Wb for the DCC sediment was lower than observed for the highest TCBP treatment. The internal body residue for total PCB for worms exposed to DCC sediment was 20-fold lower than TCBP in worms exposed to the lowest TCBP treatment on a molar basis. Comparing body residues of total PCB to TCBP assumes that the PCB congeners act additively on a molar basis. The DCC site contained a higher proportion of coarse material and a lower organic carbon concentration. The difference in sediment characteristics was assumed to be responsible for differences in the Wb.
Interlaboratory comparison of a reduced volume marine sediment toxicity test method using the amphipod Ampelisca abdita
Authors: Ferretti James A. , Calesso Diane F. , Lazorchak James M. , Dolce Thomas J. , Arnold Jennifer , Goodfellow William L. , Smith Mark E. , Serbst Jonathan R. 
Published: March 2005

Abstract
The U.S. Environmental Protection Agency has standardized methods for performing acute marine amphipod sediment toxicity tests. A test design reducing sediment volume from 200 to 50 ml and overlying water from 600 to 150 ml was recently proposed. An interlaboratory comparison was conducted to evaluate the precision of this reduced sediment volume toxicity test method using the marine amphipod Ampelisca abdita. A negative control and three sediment samples of varying degrees of toxicity ranging from low to high were tested by six laboratories. Complete agreement was reached in rank of relative toxicity for all samples tested by five out of six laboratories. Test acceptability for control survival was achieved by all laboratories, and 69% agreement in classification of the sediments as toxic or nontoxic was documented. Coefficients of variation in all test samples were similar to those reported in other interlaboratory studies using marine amphipods. Results of this study indicate that the reduced sediment volume test using A. abdita is a reliable and precise measure of acute toxicity in marine sediment samples.
Mechanistic approaches for evaluating the toxicity of reactive organochlorines and epoxides in green algae
Authors: Niederer Christian , Behra Renata , Harder Angela , Schwarzenbach René P. , Escher Beate I. 
Published: March 2005

Abstract
Reactive electrophilic chemicals, such as reactive organochlorine compounds or epoxides, react specifically with a broad spectrum of nucleophilic biomolecules, including proteins and DNA. Conventional toxicity tests for algae, involving the observation of growth inhibition, i.e., the inhibition of cell multiplication, after several days, yield unreliable information for risk assessment because reactive compounds hydrolyze to different extents during the exposure period. The diversity of their modes of toxic action further complicates effect assessment and calls for methods yielding additional information on the mechanisms of toxicity. One of the primary targets of reactive chemicals in cells is the tripeptide glutathione (GSH), which is important for detoxification but can also be regarded as a toxicity sensor because changes in glutathione levels indicate stress. A vital system for algae is the photosynthetic system, which is indirectly affected by reactive chemicals. The test systems developed in this study for the assessment of reactive toxicity toward algae were therefore based not only on nonspecific toxicity indicators like growth inhibition but also on indicators for disturbance of photosynthesis (inhibition of photosystem II quantum yield) and glutathione metabolism. The application of the developed test systems on Scenedesmus vacuolatus after short-term exposure of 2 h showed that these tests can be used as fast screening tests for algal toxicity and in mode-of-action-based test batteries.
Harbor seals (Phoca vitulina) in British Columbia, Canada, and Washington State, USA, reveal a combination of local and global polychlorinated biphenyl, dioxin, and furan signals
Authors: Ross Peter S. , Jeffries Steven J. , Yunker Mark B. , Addison Richard F. , Ikonomou Michael G. , Calambokidis John C. 
Published: March 2005

Abstract
The harbor seal (Phoca vitulina) can serve as a useful indicator of food web contamination by persistent organic pollutants (POPs) because of its high trophic level, wide distribution in temperate coastal waters of the Northern Hemisphere, and relative ease of capture. In 1996 through 1997, we live-captured 60 harbor seal pups from three regions, spanning remote (Queen Charlotte Strait, BC, Canada), moderately industrialized (Strait of Georgia, BC, Canada), and heavily industrialized (Puget Sound, WA, USA) marine basins straddling the Canada-United States border. Biopsy samples of blubber were taken and analyzed for congener-specific polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins (PCDDs), and polychlorinated dibenzofurans (PCDFs) by using high-resolution gas chromatography-high-resolution mass spectrometry. Harbor seals in Puget Sound were heavily contaminated with PCBs, whereas seals from the Strait of Georgia had relatively high concentrations of PCDDs and PCDFs. Pattern evaluation and principal components analysis suggested that proximity to sources influenced the mixture to which seals were exposed, with those inhabiting more remote areas being exposed to lighter PCB congeners (those with lower Henry's law constant and KOW) that disperse more readily through atmospheric and other processes. Total toxic equivalents to 2,3,7,8-tetrachlorodibenzo-p-dioxin for the PCBs, PCDDs, and PCDFs suggest that Puget Sound seals are at greatest risk for adverse health effects, and that PCBs represent the class of dioxinlike contaminants of greatest concern at all sites.
Web search strategies and human individual differences: Cognitive and demographic factors, Internet attitudes, and approaches
Authors: Ford Nigel , Miller David , Moss Nicola 
Published: March 2005

AbstractThe research reported here was an exploratory study that sought to discover the effects of human individual differences on Web search strategy. These differences consisted of (a) study approaches, (b) cognitive and demographic features, and (c) perceptions of and preferred approaches to Web‐based information seeking. Sixty‐eight master's students used AltaVista to search for information on three assigned search topics graded in terms of complexity. Five hundred seven search queries were factor analyzed to identify relationships between the individual difference variables and Boolean and best‐match search strategies. A number of consistent patterns of relationship were found. As task complexity increased, a number of strategic shifts were also observed on the part of searchers possessing particular combinations of characteristics. A second article (published in this issue of JASIST; Ford, Miller, & Moss, 2005) presents a combined analyses of the data including a series of regression analyses.
Contribution of morphometry in the differential diagnosis of fine‐needle thyroid aspirates
Authors: Karslıoğlu Yıldırım , Celasun Bülent , Günhan Ömer 
Published: March 2005

AbstractBackgroundCytologic discrimination of cellular nodules, follicular adenoma, and follicular carcinoma in the thyroid is problematic. Methods are needed to achieve a reliable diagnosis. Some sophisticated tools, such as microarrays, offer great potential but lack accompanying morphologic information.MethodsOne hundred twelve samples obtained from patients with lesions histopathologically diagnosed as nodular goiter, follicular adenoma, follicular carcinoma, and papillary carcinoma were used. Eight geometric features, such as nuclear area and circular form factor, were measured. The dataset was divided into six overlapping groups to represent the frequently encountered situations in routine practice. Multivariate analysis of variance, Tukey's honestly significant differences test, and discriminant analysis were performed. Statistical analysis was carried out with two conceptually different approaches. In the first, data from all measured nuclei were used. In the second, a subset of data representing the most extreme values of variables was extracted from the entire dataset to simulate the “selection procedure” performed during conventional morphologic examination.ResultsWhen the selected dataset instead of data from all measured nuclei was used, the correct classification rates in discriminant analysis improved considerably.ConclusionsMorphologic examination is based primarily on selection. Using data obtained from all of the cells in morphometry may cause a dilution effect in diagnostically important features. Morphometric studies may also be planned with a proper selection “bias.” This may be particularly helpful when isolated abnormal cells carry most of the diagnostic information. © 2005 Wiley‐Liss, Inc.
Inhibitors of ubiquitin‐dependent proteolysis can delay programmed cell death of adult intersegmental muscles in the moth Manduca sexta
Authors: Bayline Ronald J. , Dean Derek M. , Booker Ronald 
Published: March 2005

AbstractIn the moth Manduca sexta, intersegmental muscles (ISMs) undergo rapid programmed cell death (PCD) within 48 hr of adult emergence. ISM PCD involves ubiquitin‐dependent proteasomal degradation accompanied by the down‐regulation of expression of actin genes and the up‐regulation of degradative gene expression such as ubiquitin. Hemin chloride and N‐acetyl‐leu‐leu‐norleucinal (ALLN), both inhibitors of proteasomal activity, administered before adult emergence delayed PCD for up to 5 days in ISMs maintained from the larval stage, such as the dorsal internal medial muscle in abdominal segment 4 (DIM‐A4). ISMs that developed during metamorphosis from respecified larval muscles such as the DIM‐A2 were less dramatically affected. The increase in polyubiquitinated proteins and the decrease in actin mRNA expression accompanying maintained ISM PCD were delayed after inhibitor application. No changes were detected in respecified ISMs. These results reveal a regulatory role for proteasomal activity in an early stage of maintained ISM cell death. Developmental Dynamics 233:445–455, 2005. © 2005 Wiley‐Liss, Inc.
Activation of catechol‐O‐methyltransferase in astrocytes stimulates homocysteine synthesis and export to neurons
Authors: Huang Guowei , Dragan Magdalena , Freeman David , Wilson John X. 
Published: March 2005

AbstractElevation of the total homocysteine (tHcy) concentration in plasma has been implicated in neurodegeneration in patients with stroke, dementia, Alzheimer disease, and Parkinson disease. Because the mechanisms controlling brain tHcy are unknown, the present study investigated its synthesis and transport in primary rat brain cell cultures. We found that the catechol‐O‐methyltransferase (COMT) substrate 3,4‐dihydroxybenzoic acid (DHB) increased export of tHcy in astrocytes, but not in neurons. The export mechanism was selective for tHcy over cyst(e)ine, total glutathione (tGSH) or cysteinylglycine (Cys‐Gly). tHcy export from astrocytes was also induced by the COMT substrates levodopa (L‐DOPA), dopamine and quercetin, and it was blocked by the COMT inhibitors tropolone and entacapone. This export was associated with increased synthesis of tHcy because both intracellular and extracellular tHcy concentrations rose during COMT activation. Incubation in cyst(e)ine‐deficient medium inhibited the tHcy export response to COMT activation. Exogenous tHcy (100 μM) was accumulated into neurons, but not into astrocytes. We conclude that activation of COMT causes sustained synthesis of Hcy in astrocytes and transport of this amino acid to neurons.© 2005 Wiley‐Liss, Inc.
Adhesion‐dependent redistribution of MAP kinase and MEK promotes muscarinic receptor‐mediated signaling to the nucleus
Authors: Slack Barbara E. , Siniaia Marina S. 
Published: March 2005

AbstractThe mitogen‐activated protein kinases (MAPKs) are activated by extracellular signals, and translocate to the nucleus where they modulate transcription. Integrin‐mediated cell adhesion to extracellular matrix (ECM) proteins is required for efficient transmission of MAPK‐based signals initiated by growth factors. However, the modulation of G protein‐coupled receptor (GPCR) signaling by adhesion is less well understood. In the present study, we assessed the impact of cell adhesion on MAPK activation by muscarinic M3 receptors. The muscarinic agonist carbachol more efficiently promoted stress fiber formation and tyrosine phosphorylation of focal adhesion‐associated proteins in M3 receptor‐expressing cells adherent to fibronectin or collagen type I, as compared to polylysine. Overall MAPK activation was robust in cells adherent to all three substrata. However, total levels of MAPK and mitogen‐activated protein kinase kinase (MEK) in the nucleus were significantly greater in cells adherent to ECM proteins for 2.5 h, and levels of activated MAPK and MEK in the nuclei of these cells were higher following carbachol stimulation, relative to levels in cells adherent to polylysine. MEK inhibitors did not prevent adhesion‐dependent translocation of MAPK and MEK to the nucleus, and increased nuclear phospho‐MEK levels in carbachol‐stimulated cells. The results suggest that adhesion of cells to ECM triggers the redistribution of MAPK and MEK to the nucleus, possibly as a result of the cytoskeletal rearrangements that accompany cell spreading. This may represent a mechanism for priming the nucleus with MEK and MAPK, leading to more rapid and pronounced increases in intranuclear phospho‐MAPK upon GPCR stimulation. © 2005 Wiley‐Liss, Inc.
A note on Ramsey numbers for books
Authors: Nikiforov Vladimir , Rousseau Cecil C. 
Published: March 2005

AbstractThe book with n pages Bn is the graph consisting of n triangles sharing an edge. The book Ramsey number r(Bm,Bn) is the smallest integer r such that either Bm ⊂ G or Bn ⊂ G for every graph G of order r. We prove that there exists a positive constant c such that r(Bm,Bn) = 2n + 3 for all n ≥ cm. Our proof is based mainly on counting; we also use a result of Andrásfai, Erdős, and Sós stating that triangle‐free graphs of order n and minimum degree greater than 2n/5 are bipartite. © 2005 Wiley Periodicals, Inc. J Graph Theory