bluuebunny/crossref_metadata_2025_split huggingface dataset:
Extended Resection for Pancreatic Adenocarcinoma
Authors: Reddy Srinevas K. , Tyler Douglas S. , Pappas Theodore N. , Clary Bryan M. 
Published: June 2007

Learning Objectives
After completing this course, the reader will be able to: Discuss the evidence in favor of and against the role of surgical resection in the management of pancreatic adenocarcinoma.Explain how the components of an extended pancreatectomy, including total pancreatectomy, extended lymph node dissection, and major intestinal arterial resection, do not improve survival above what is provided after pancreaticoduodenectomy and are associated with substantial morbidity.Discuss how portal/mesenteric vein resection to achieve negative resection margins does not add to the morbidity of pancreaticoduodenectomy, does not worsen survival after resection, and is most often performed because of tumor location.
CME Access and take the CME test online and receive 1 AMA PRA Category 1 Credit™ at CME.TheOncologist.com
New Drugs for Myeloma
Authors: Richardson Paul G. , Mitsiades Constantine , Schlossman Robert , Munshi Nikhil , Anderson Kenneth 
Published: June 2007

Learning Objectives
After completing this course, the reader will be able to: Discuss the impact of novel agents on the treatment paradigm for multiple myeloma.Explain the importance of combination regimens and in particular the ability to rechallenge patients with a combination of drugs that may each have been administered separately before.Describe the toxicity profiles of the agents being used with a focus on key side effects and discuss the potential value of these agents in special populations, such as those with renal failure.
CME Access and take the CME test online and receive 1 AMA PRA Category 1 Credit™ at CME.TheOncologist.com
Evaluation of the reproductive effects of tamoxifen citrate in partial and full life-cycle studies using fathead minnows (Pimephales Promelas)
Authors: Williams Tim D. , Caunter John E. , Lillicrap Adam D. , Hutchinson Thomas H. , Gillings Edward G. , Duffell Stephen 
Published: June 2007

AbstractLaboratory studies were conducted to investigate potential adverse effects on development, growth, reproduction and biomarker responses (vitellogenin [VTG] and gonad histology) in fathead minnows (Pimephales promelas) exposed to tamoxifen citrate. Based on the results of a partial life cycle study (nominal [mean measured] concentrations ranged from 0.18 [0.11] to 18 [15.74] μg/L), a 284-d fish full life-cycle (FFLC) flow-through study was conducted using newly fertilized embryos (&lt;24 h postfertilization) exposed to nominal (mean measured) concentrations of 14C-tamoxifen citrate that ranged from 0.01 (0.007) to 5.12 (4.08) μg/L. Triethylene glycol (2.0 μl/L) was used as a solvent carrier, with 17β-estradiol (E2) as a positive control (nominal 0.1 μg/L). Among the biomarkers measured, significant effects on VTG and gonad histology were observed, although these results required care in their interpretation. Among important population-relevant endpoints, no effects on reproduction were observed at nominal concentrations ≤5.12 μg/L. Effects on growth (length and weight) were observed in some treatments; however, some of these showed irregular concentration-response relationships, which made interpretation uncertain, or were deemed transient in nature (e.g., reduction in growth of F1 28-d posthatch larval fish at nominal concentrations of 0.08, 0.64, and 5.12 μg/L) and judged not to be biologically significant. Interpretation of results from fish chronic studies is challenging and frequently calls for scientific judgement about statistical and biological significance and what constitutes an adverse effect. Using the principles used in mammalian toxicology studies, data from partial and FFLC studies were evaluated from both statistical and biological perspectives in order to determine no-observed-adverse effect concentrations (expressed as adverseNOEC) for use in environmental risk assessment. Careful consideration of both biological and statistical outcomes from these studies suggested overall adverseNOEC concentration and lowest-observed-effect concentration (adverseLOEC) values for tamoxifen citrate of 5.12 μg/L and 5.6 μg/L, respectively.
Development of a daphnia magna DNA microarray for evaluating the toxicity of environmental chemicals
Authors: Watanabe Hajime , Takahashi Eri , Nakamura Yuko , Oda Shigeto , Tatarazako Norihisa , Iguchi Taisen 
Published: June 2007

Abstract
Toxic chemical contaminants have a variety of detrimental effects on various species, and the impact of pollutants on ecosystems has become an urgent issue. However, the majority of studies regarding the effects of chemical contaminants have focused on vertebrates. Among aquatic organisms, Daphnia magna has been used extensively to evaluate organism- and populationlevel responses of invertebrates to pollutants in acute toxicity or reproductive toxicity tests. Although these types of tests can provide information concerning hazardous concentrations of chemicals, they provide no information about their mode of action. Recent advances in molecular genetic techniques have provided tools to better understand the responses of aquatic organisms to pollutants. In the present study, we adapted some of the techniques of molecular genetics to develop new tools, which form the basis for an ecotoxicogenomic assessment of D. magna. Based on a Daphnia expressed sequence tag database, we developed an oligonucleotide-based DNA microarray with high reproducibility. The DNA microarray was used to evaluate gene expression profiles of neonatal daphnids exposed to several different chemicals: Copper sulfate, hydrogen peroxide, pentachlorophenol, or β-naphthoflavone. Exposure to these chemicals resulted in characteristic patterns of gene expression that were chemical-specific, indicating that the Daphnia DNA microarray can be used for classification of toxic chemicals and for development of a mechanistic understanding of chemical toxicity on a common freshwater organism.
The effects of three organic chemicals on the upper thermal tolerances of four freshwater fishes
Authors: Patra Ronald W. , Chapman John C. , Lim Richard P. , Gehrke Peter C. 
Published: June 2007

AbstractThe upper temperature tolerance limits of four freshwater fish species, silver perch Bidyanus bidyanus, eastern rainbowfish Melanotaenia duboulayi, western carp gudgeon Hypseleotris klunzingeri, and rainbow trout Oncorhynchus mykiss, were determined using the critical thermal maximum (CTMaximum) method. The CTMaximum tests were carried out with unexposed fish and fish exposed to sublethal concentrations of endosulfan, chlorpyrifos, and phenol to determine whether or not the CTMaximum was affected. The CTMaximum temperature of B. bidyanus decreased by 2.8, 3.8, and 0.3°C on exposure to endosulfan, chlorpyrifos, and phenol, respectively. Similarly, in M. duboulayi, the CTMaximum was decreased by 4.1, 2.5, and 0°C, while in H. klunzingeri it decreased by 3.1, 4.3, and 0.1°C, respectively, and in O. mykiss by 4.8, 5.9, and 0.7°C, respectively. Exposure to sublethal test concentrations of endosulfan and chlorpyrifos caused significant (p ≤ 0.0001) reductions in CTMaximum values for all fish species compared to that of unexposed fish. However, exposure to phenol did not cause any significant (p ≥ 0.05) change of CTMaximum temperatures.
Effect of carbon nanotubes on developing zebrafish (Danio Rerio) embryos
Authors: Cheng Jinping , Flahaut Emmanuel , Cheng Shuk Han 
Published: June 2007

AbstractThe impact of carbon nanotubes (CNTs) on the aquatic environment was investigated by examining the properties of raw CNTs under several environmental conditions and using developing zebrafish (Danio rerio) embryos. The agglomerate size for single-walled CNTs (SWCNTs) was significantly larger at pH 11 or greater and was stable at temperatures from 4 to 40°C and salinities from 0 to 30 ppt. Exposure to SWCNTs induced a significant hatching delay in zebrafish embryos between 52 to 72 h postfertilization (hpf) at concentrations of greater than 120 mg/L, but 99% of the exposed embryos hatched by 75 hpf. Double-walled CNTs also induced a hatching delay at concentrations of greater than 240 mg/L, but carbon black did not affect hatching at the concentrations tested. Molecular and cellular analysis showed that the embryonic development of the exposed embryos up to 96 hpf was not affected at SWCNT concentrations of up to 360 mg/L. Scanning-electron microscopic inspection showed that the size of the pores on the embryo chorion was nanoscaled and that the size of SWCNT agglomerates was microscaled or larger, indicating that the chorion of zebrafish embryos was an effective protective barrier to SWCNT agglomerates. The hatching delay observed in this study likely was induced by the Co and Ni catalysts used in the production of SWCNTs that remained at trace concentrations after purification. This study suggests that materials associated with raw SWCNTs (perhaps metal contaminants) have the potential to affect aquatic life when released into the aquatic environment.
Quantitative structure-activity relationship modeling on in vitro endocrine effects and metabolic stability involving 26 selected brominated flame retardants
Authors: Harju Mikael , Hamers Timo , Kamstra Jorke H. , Sonneveld Edwin , Boon Jan P. , Tysklind Mats , Andersson Patrik L. 
Published: June 2007

Abstract
In this work, quantitative structure—activity relationships (QSARs) were developed to aid human and environmental risk assessment processes for brominated flame retardants (BFRs). Brominated flame retardants, such as the high-production-volume chemicals polybrominated diphenyl ethers (PBDEs), tetrabromobisphenol A, and hexabromocyclododecane, have been identified as potential endocrine disruptors. Quantitative structure—activity relationship models were built based on the in vitro potencies of 26 selected BFRs. The in vitro assays included interactions with, for example, androgen, progesterone, estrogen, and dioxin (aryl hydrocarbon) receptor, plus competition with thyroxine for its plasma carrier protein (transthyretin), inhibition of estradiol sulfation via sulfotransferase, and finally, rate of metabolization. The QSAR modeling, a number of physicochemical parameters were calculated describing the electronic, lipophilic, and structural characteristics of the molecules. These include frontier molecular orbitals, molecular charges, polarities, log octanol/water partitioning coefficient, and two- and three-dimensional molecularproperties. Experimental properties were included and measured for PBDEs, such as their individual ultraviolet spectra (200–320 nm) and retention times on three different high-performance liquid chromatography columns and one nonpolar gas chromatography column. Quantitative structure—activity relationship models based on androgen antagonism and metabolic degradation rates generally gave similar results, suggesting that lower-brominated PBDEs with bromine substitutions in ortho positions and bromine-free meta- and para positions had the highest potencies and metabolic degradation rates. Predictions made for the constituents of the technical flame retardant Bromkal 70–5DE found BDE 17 to be a potent androgen antagonist and BDE 66, which is a relevant PBDE in environmental samples, to be only a weak antagonist.
Predicting metal uptake by wetland plants under aerobic and anaerobic conditions
Authors: van der Welle Marlies E.W. , Roelofs Jan G.M. , den Camp Huub J.M. Op , Lamers Leon P.M. 
Published: June 2007

Abstract
Metal pollution can be a serious threat to ecosystems at a global scale. Although the bioavailability of potentially toxic metals is determined by many biotic and abiotic factors, including pH and redox potential, total metal concentrations in the soil are used widely to assess or predict toxicity. In the present study we tested the effect of desiccation of soils differing in acidification potential and total heavy metal contamination on the growth and metal uptake of three typical, common wetland species: Caltha palustris, Juncus effusus, and Rumex hydrolapathum. We found that plant growth in wet soils mainly was determined by nutrient availability, though in dry soils the combined effects of acidification and increased metal availability prevailed. Metal uptake under anaerobic conditions was best predicted by the acidification potential (sediment S/[Ca + Mg] ratio), not by total metal concentrations. We propose that this is related to radial oxygen loss by wetland plant roots, which leads to acidification of the rhizosphere. Under aerobic conditions, plant metal uptake was best predicted by the amount of CaCl2-extractable metals. We conclude that total metal concentrations are not suitable for predicting bioavailability and that the above diagnostic parameters will provide insight into biogeochemical processes involved in toxicity assessment and soil policy.
Chlorophyll a fluorescence as a biomarker for rapid toxicity assessment
Authors: Fai Patricia Bi , Grant Alastair , Reid Brian 
Published: June 2007

Abstract
Algal growth assays are the most frequently used methods to detect herbicide toxicity in environmental samples; however, these require several days to detect reductions in growth rate with adequate precision. Hence, a need exists for more rapid assays. Two in vivo chlorophyll a fluorescence assays, one using pulse-amplitude modulation (PAM) fluorescence and another based on fluorescence at 684 and 735 nm, detect the effects of photosystem (PS) II inhibitors (atrazine, diuron, and isoproturon) on Selenastrum capricornutum Printz only after 1 h and 30 min, respectively, of incubation. The median growth inhibition (IC50) could be predicted reliably from effects on three PAM parameters—maximal PSII quantum yield (ϕm), operational quantum yield (ϕ'm), and nonphotochemical quenching—and from measurements of fluorescence at 684 and 735 nm. The effects of the PSI inhibitor paraquat dichloride, were smaller in magnitude and could be detected after a 24-h incubation. These two in vivo chlorophyll a fluorescence assays can thus provide reliable, rapid, and cost-effective tools to screen toxicity caused by PSII inhibitors. Neither of the two fluorescence assays could consistently predict the effects of nonphotosynthetic inhibitors (alachlor, metsulfuron methyl, and diclofop methyl).
Effects of proposed physical ballast tank treatments on aquatic invertebrate resting eggs
Authors: Raikow David F. , Reid David F. , Blatchley Ernest R. , Jacobs Gregory , Landrum Peter F. 
Published: June 2007

Abstract
Adaptations in aquatic invertebrate resting eggs that confer protection from natural catastrophic events also could confer protection from treatments applied to ballast water for biological invasion vector management. To evaluate the potential efficacy of physical ballast water treatment methods, the present study examined the acute toxicity of heat (flash and holding methods), ultraviolet (UV) radiation (254 nm), and deoxygenation (acute and chronic) on resting eggs of the freshwater cladoceran Daphnia mendotae and the marine brine shrimp Artemia sp. Both D. mendotae and Artemia sp. were similarly sensitive to flash exposures of heat (100% mortality at 70°C), but D. mendotae were much more sensitive to prolonged exposures. Exposure to 4,000 mJ/cm2 of UV radiation resulted in mortality rates of 59% in Artemia sp. and 91% in D. mendotae. Deoxygenation to an oxygen concentration of 1 mg/L was maximally toxic to both species. Deoxygenation suppressed hatching of D. mendotae resting eggs at oxygen concentrations of less than 5.5 mg/L and of Artemia sp. resting eggs at concentrations of less than 1 mg/L. Results suggest that UV radiation and deoxygenation are not viable treatment methods with respect to invertebrate resting eggs because of the impracticality of producing sufficient UV doses and the suppression of hatching at low oxygen concentrations. Results also suggest that the treatment temperatures required to kill resting eggs are much higher than those reported to be effective against other invertebrate life stages and species. The results, however, do not preclude the effectiveness of these treatments against other organisms or life stages. Nevertheless, if ballast tank treatment systems employing the tested methods are intended to include mitigation of viable resting eggs, then physical removal of large resting eggs and ephippia via filtration would be a necessary initial step.
Aqueous exposure to 4-nonylphenol and 17β-estradiol increases stress sensitivity and disrupts ion regulatory ability of juvenile Atlantic salmon
Authors: Lerner Darren T. , Björnsson Björn Thrandur , McCormick Stephen D. 
Published: June 2007

Abstract
Population declines of wild Atlantic salmon have been attributed to an array of anthropogenic disturbances, including dams, commercial and recreational fishing, habitat loss, and pollution. Environmental contaminants in particular, can act as environmental stressors on fish, typically causing disruption of ion homeostasis due to their close association with the aquatic environment. To examine the effects of the xenoestrogen 4-nonylphenol (NP) or 17β-estradiol (E2) on stress sensitivity and ion regulation, we exposed juvenile Atlantic salmon continuously for 21 d to either 10 or 100 μg/L NP (NP-L or NP-H), 2 μg/L E2 (positive control), or vehicle control during the parr-smolt transformation in April. After treatment, fish were sampled in freshwater (FW), transferred to 30‰ seawater (SW) for 24 h, or subjected to a handling stress. Estradiol and NP-H increased plasma vitellogenin in males and females, and E2 increased gonadosomatic index only in males. In FW, E2 reduced sodium potassium–activated adenosine triphosphatase activity as well as plasma levels of growth hormone, insulin-like growth factor I, and triiodothyronine. Both E2 and NP-H reduced plasma sodium in FW and increased plasma chloride in SW. Plasma Cortisol levels pre- and poststressor were significantly elevated by all treatments relative to controls, but only E2 increased plasma glucose before and after the stressor. These results indicate that exposure of anadromous salmonids to environmental estrogens heightens sensitivity to external stressors, impairs ion regulation in both FW and SW, and disrupts endocrine pathways critical for smolt development.
The effect of food rations on tissue-specific copper accumulation patterns of sublethal waterborne exposure in Cyprinus carpio
Authors: Hashemi Shodja , Blust Ronny , de Boeck Gudrun 
Published: June 2007

Abstract
Common carp (Cyprinus carpio) were fed to two different food rations, 0.5% body weight (low ration [LR]) and 5% body weight (high ration [HR]), and were exposed to sublethal (1 μM) copper levels for 28 d in softened Antwerp (Belgium) city tap water (Ca2+, 79.3 mg/L; Mg2+, 7.4 mg/L; Na+, 27.8 mg/L; pH 7.5–8.0). Copper accumulations in the liver, gills, kidney, anterior intestine, posterior intestine, and muscle were determined. Copper accumulation in the gills, liver, and kidney of LR fish was significantly higher than in HR fish. The only time copper uptake in HR fish was significantly higher than in LR fish was in the posterior intestine after two weeks of exposure. No difference was found between the two rations in the anterior intestine. Copper accumulation in the liver of both feeding treatments occurred in a time-dependent manner and did not reach steady state in any treatment. On the contrary, copper concentration in the gills reached a steady state for both HR and LR fish within the first week of exposure. No copper accumulation was found in muscle tissues of either treatment. Copper concentration dropped to control levels in all tissues, except liver tissue, two weeks after the exposure ended. Our studies indicated that copper uptake was influenced by the food ration in carp. The difference in copper accumulation probably is related to the amount of dietary NaCl and different rates of metallothionein synthesis. Low food availability provides less Na+ influx and leads to increased brachial uptake of Na+ and copper. In addition, it has been shown that starved animals show increased levels of metallothionein, possibly causing higher copper accumulation.
Effects of 17α-ethinylestradiol and bisphenol a on vertebral development in the fathead minnow (Pimephales Promelas)
Authors: Warner Kara E. , Jenkins Jeffrey J. 
Published: June 2007

Abstract
Growth, reproductive ability, and metabolic functions may be impaired by disruption of early endocrine patterning. Natural and synthetic estrogens detected in surface waters have been linked to reproductive endocrine signaling disruption in several species. The present study characterizes the nonreproductive morphological endpoint of vertebral anomalies in fish exposed to environmental estrogens. Estrogen is a proliferation-inducing compound in osteoblasts, regulating cartilage and bone deposition during development in vertebrates. The hypothesis for the present work is that xenobiotics with estrogenic activity adversely impact vertebral bone formation. Fathead minnows (Pimephales promelas) were exposed to 0.1 to 100 μg/L 17α-ethinylestradiol (EE2) and 0.1 to 1,000 μg/L bisphenol A (BPA) from egg stage (24 h postfertilization) to 25 to 26 d posthatch. Fish were measured for length and analyzed microscopically to determine degree of skeletal development (developmental score) and the occurrence of spinal abnormalities, including vertebral compression, bone fusion, and spinal curvatures. Fish length and developmental score were inversely related to vertebral malformations in exposed fish. Skeletal developmental was affected significantly in EE2-exposed fish: Vertebral malformations were observed in up to 62% of fish in a nonmonotonic dose-response. However, BPA did not significantly impair skeletal development or induce vertebral malformations. The bioassay results suggest vertebral bone development is a potential endpoint of endocrine disruption from potent estrogenic compounds in surface waters.
Subacute toxicity of oral 2,6-dinitrotoluene and 1,3,5-trinitro-1,3,5-triazine (RDX) exposure to the northern bobwhite (Colinus virginianus)
Authors: Johnson Mark S. , Quinn Michael J. , Bazar Matthew A. , Gust Kurt A. , Escalon B. Lynn , Perkins Edward J. 
Published: June 2007

AbstractMilitary activities associated with training have resulted in soil residues of munition compounds and their breakdown products. Often, these areas are valuable habitats used by birds. To evaluate the possibility of adverse effects in birds, the effects from oral exposures of 2,6-dinitrotoluene (2,6-DNT) and 1,3,5-trinitro-1,3,5-triazine (RDX) were tested using a controlled dosing regime in northern bobwhite (Colinus virginianus). Nine groups of birds of mixed sex received either corn oil or 50, 100, 190, or 350 mg 2,6-DNT/kg body weight/d or 20, 80, 125, or 180 mg RDX/kg body weight/d mixed in corn oil via gavage for 14 d. Etiology of disease was markedly different between compounds. Increased RDX exposure caused an inverse relationship to time of death, symptoms including clonic followed by tonic convulsions, and death shortly thereafter. Brain concentrations of RDX postmortem, however, were relatively consistent (mean ± standard error, 20.5 ± 2.9 mg/kg tissue). Observations of 2,6-DNT effects included gastrointestinal distress, dehydration, and a reduction in body mass and feed consumption. Together, these data suggest that RDX is more toxic from short, repeated exposures than 2,6-DNT, resulting in central nervous system—related effects, whereas 2,6-DNT causes gastrointestinal disturbances at higher exposures.