bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sensitivity of juvenile freshwater mussels (Lampsilis fasciola, Villosa iris) to total and un-ionized ammonia
Authors: Mummert Andrea K. , Neves Richard J. , Newcomb Tammy J. , Cherry Donald S. 
Published: November 2004

Abstract
This study evaluated the sensitivity of juveniles of two freshwater unionid mussel species (Villosa iris [Lea] and Lampsilis fasciola [Rafinesque]) to un-ionized and total ammonia. Five concentrations of ammonium chloride were tested using 96-h staticrenewal toxicity tests at 12 and 20°C. Based on their respective mean 96-h lethal concentration to 50% (LC50s), V. iris (0.11 mg/ L NH3-N) was more sensitive than L. fasciola (0.26 mg/L NH3-N). At 96 h, significant differences in sensitivity to un-ionized ammonia between the two temperatures were not observed for either species. Comparison of LC50s reported for other aquatic organisms to the 96-h LC50s calculated for juvenile L. fasciola and V. iris shows these two mussel species to be among the most sensitive to un-ionized ammonia. Based on reported levels of un-ionized ammonia in the aquatic environment from anthropogenic sources, un-ionized ammonia may be an important limiting toxicological factor to freshwater mussel populations.
Effect of nonaqueous-phase liquids on the availability of polycyclic aromatic hydrocarbons in soil for worm uptake and bacterial genotoxicity
Authors: Quiñones-Rivera Antonio , Alexander Renee R. , Alexander Martin 
Published: November 2004

Abstract
A study was conducted to determine the effect of nonaqueous-phase liquids (NAPLs) on the bioavailability of benzo[a]pyrene (BaP) in soil. Sentry 19 oil and pristane reduced the availability of BaP for assimilation by the earthworm Eisenia fetida and for mutagenicity in a rifampicin-sensitive strain of Pseudomonas putida. As much as 80% of the compound could be rendered unavailable to the worms or for genotoxicity. Tests with five alkanes and an oil showed that the extent of reduction in genotoxicity of BaP varied with the identity, viscosity, and hydrophobicity of the NAPL. The magnitude of the decline in availability for genotoxicity differed in tests of three soils. Because little or no BaP was lost from the soil, the diminished bioavailability was not the result of a diminished total concentration of the compound. These findings show that exposure to hydrophobic toxicants can be appreciably altered in soils containing NAPLs.
Temperature influences on water permeability and chlorpyrifos uptake in aquatic insects with differing respiratory strategies
Authors: Buchwalter David B. , Jenkins Jeffrey J. , Curtis Lawrence R. 
Published: November 2004

Abstract
Aquatic insects have evolved diverse respiratory strategies that range from breathing atmospheric air to breathing dissolved oxygen. These strategies result in vast morphological differences among taxa in terms of exchange epithelial surface areas that are in direct contact with the surrounding water that, in turn, affect physiological processes. This paper examines the effects of acute temperature shifts on water permeability and chlorpyrifos uptake in aquatic insects with different respiratory strategies. While considerable differences existed in water permeability among the species tested, acute temperature shifts raised water influx rates similarly in air-breathing and gill-bearing taxa. This contrasts significantly with temperature-shift effects on chlorpyrifos uptake. Temperature shifts of 4.5°C increased 14C-chlorpyrifos accumulation rates in the gill-bearing mayfly Cinygma sp. and in the air-breathing hemipteran Sigara washingtonensis. However, the temperature-induced increase in 14C-chlorpyrifos uptake after 8 h of exposure was 2.75-fold higher in Cinygma than in Sigara. Uptake of 14C-chlorpyrifos was uniformly higher in Cinygma than in Sigara in all experiments. These findings suggest that organisms with relatively large exchange epithelial surface areas are potentially more vulnerable to both osmoregulatory distress as well as contaminant accumulation. Temperature increases appear more likely to impact organisms that have relatively large exchange epithelial surface areas, both as an individual stressor and in combination with additional stressors such as contaminants.
Concentrations of organochlorine pesticides and polychlorinated biphenyls in amphipods (Gammarus lacustris) along an elevation gradient in mountain lakes of western Canada
Authors: Blais Jules M. , Wilhelm Frank , Kidd Karen A. , Muir Derek C. G. , Donald David B. , Schindler David W. 
Published: November 2004

Abstract
Populations of the amphipod Gammarus lacustris were examined for their concentrations of organochlorine pesticides and polychlorinated biphenyls (PCBs) from seven lakes spanning a 1,300-m elevation gradient in Alberta, Canada. The concentrations of several of the semivolatile organochlorine compounds ([SVOCs], vapor pressure &gt; 0.03 Pa at 20°C) increased at higher altitudes. This pattern was generally not observed among the less volatile organochlorines ([LVOCs], vapor pressure &lt; 0.03 Pa at 20°C). These same SVOC compounds have been previously shown to increase at high latitudes as a result of their long-range transport and preferential deposition in cold climates. We also show that populations of G. lacustris at high elevations have slower growth rates and store more lipids than populations at lower elevations. To resolve the colinearity of independent variables, we used multiple regression to identify patterns of contaminant concentrations in this data set. Multiple regressions showed that the effect of elevation, lipid content, and temperature on contaminant concentrations was no longer significant once the growth rate of Gammarus was included as an independent variable. This study shows that enrichment of SVOCs occurs in Gammarus at high altitudes in Alberta, Canada, and that growth rate (biodilution) appears to be the primary influence. Because Gammarus is an important trophic link in aquatic foodwebs in these environments, enhanced concentrations of toxicants in prey may increase their biomagnification in top predators of high-altitude lakes.
Chemical contaminants and biological indicators of mussel health during gametogenesis
Authors: Hellou Jocelyne , Yeats Phil , Steller Sean , Gagné Francois 
Published: November 2004

Abstract
Mytilus edulis were collected intertidally from three locations in Halifax Harbor, Nova Scotia, on five occasions during spring and summer 2000. Bioindicators of health (lipid content), condition and gonad indices (CI and GI), and sex ratio, as well as vitellins, were compared with the bioaccumulation of polycyclic aromatic compounds (PACs) including polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), coprostanol, and metals. Twice as many male as female mussels were collected from a downtown site (M8) close to numerous raw sewage effluents and a naval dockyard. Males from M8 had a high lipid content, and females had a delayed production of vitellins. These mussels also displayed the highest levels of PACs, coprostanol, Ag, and Sn. Coprostanol and silver are sewage markers in sediments, and their presence in mussels confirms exposure to sewage effluents. Female mussels were more abundant in an area outside the industrialized part of the harbor that had higher marine traffic (M14); displayed higher levels of vitellins in gonads; had similar time trends for CI and GI; and had some similar metals compared with mussels from M8. The lowest variability in biomarkers was observed at a site in a mostly residential arm of the harbor (M12), which was expected to be more pristine based on an earlier investigation. Compared to mussels in M14, the mussels of M12 had the lowest condition indices and PCB concentrations and low but similar levels of lipids, PACs, and coprostanol. They also displayed the highest concentrations of Cd, Cu, Pb, and Hg, and females had the highest gonad indices early in the season.
Limitations of current risk characterization methods in probabilistic environmental risk assessment
Authors: Verdonck Frederik A. M. , Aldenberg Tom , Jaworska Joanna , Vanrolleghem Peter A. 
Published: November 2004

Abstract
In probabilistic environmental risk assessment, the likelihood and the extent of adverse effects occurring in ecological systems because of exposure(s) to substances are estimated. It is based on the comparison of an exposure/environmental concentration distribution, with a species sensitivity distribution derived from toxicity data. The calculation of a probabilistic risk can be performed in many ways (e.g., area under the curve in joint probability curves). However, several (hypothetical) examples and some theoretical considerations illustrate that the current risk characterisation methods have an integrative character and they focus on the statistical comparison of two distributions without properly considering the environmental interpretation of these underlying distributions. Several scenarios with varying exposure/environmental concentration distribution and species sensitivity distribution standard deviations are discussed.
Determination of the surface sorption properties of talc, different salts, and clay minerals at various relative humidities using adsorption data of a diverse set of organic vapors
Authors: Goss Kai-Uwe , Buschmann Johanna , Schwarzenbach René P. 
Published: November 2004

Abstract
Adsorption constants of a diverse set of organic vapors have been measured on NaCl, KNO3, (NH4)2SO4, NH4Cl, kaolinite, bentonite, and talc at different relative humidities at 15°C. Together with the earlier studied quartz (SiO2), CaCO3, and α-Al2O3, these surfaces represent relevant sorbents for organic vapors in the environment. An equation that describes the van der Waals and H-bond interactions between the sorbate and the surface can be used to describe the sorbate and sorbent variability in the measured data and to predict sorption constants of organic compounds that have not been tested on the respective surface. The unknown properties of the sorbent surfaces are used as fitting parameters in this equation. These data provide important insights into the variability of sorption properties of natural, inorganic surfaces as a function of relative humidity.
Bright and Efficient, Non‐Doped, Phosphorescent Organic Red‐Light‐Emitting Diodes
Authors: Song Y.‐H. , Yeh S.‐J. , Chen C.‐T. , Chi Y. , Liu C.‐S. , Yu J.‐K. , Hu Y.‐H. , Chou P.‐T. , Peng S.‐M. , Lee G.‐H. 
Published: November 2004

AbstractIr(III)metal complexes with formula [(nazo)2Ir(Fppz)] (1), [(nazo)2Ir(Bppz)] (2), and [(nazo)2Ir(Fptz)] (3) [(nazo)H = 4‐phenyl quinazoline, (Fppz)H = 3‐trifluoromethyl‐5‐(2‐pyridyl) pyrazole, (Bppz)H = 3‐t‐butyl‐5‐(2‐pyridyl) pyrazole, and (Fptz)H = 3‐trifluoromethyl‐5‐(2‐pyridyl) triazole] were synthesized, among which the exact configuration of1was confirmed using single‐crystal X‐ray diffraction analysis. These complexes exhibited bright red phosphorescence with relatively short lifetimes of 0.4–1.05 μs in both solution and the solid‐state at room temperature. Non‐doped organic light‐emitting diodes (OLEDs) were fabricated using complexes1and2in the absence of a host matrix. Saturated red electroluminescence was observed at λmax = 626 nm (host‐emitter complex 1) and 652 nm (host‐emitter complex 2), which corresponds to coordinates (0.66,0.34) and (0.69,0.31), respectively, on the 1931 Commission Internationale de l'Eclairage (CIE) chromaticity diagram. The non‐doped devices employing complex 1showed electroluminance as high as 5780 cd m–2, an external quantum efficiency of 5.5 % at 8 V, and a current density of 20 mA cm–2. The short phosphorescence lifetime of1in the solid state, coupled with its modest π–π stacking interactions, appear to be the determining factors for its unusual success as a non‐doped host‐emitter.
Intraoperative adverse events and outcome after anterior resection of the rectum
Authors: Matthiessen P , Hallböök O , Rutegård J , Sjödahl R 
Published: November 2004

Abstract

Background
The aim of this population-based study was to analyse the relationship between intraoperative adverse events and outcome after anterior resection.

Methods
All 140 patients who underwent elective anterior resection in Sweden between 1987 and 1995, and who died within 30 days, were compared with a group of 423 randomly selected patients who underwent the same procedure during the same interval but survived the operation. Intraoperative adverse events and intraoperative measures taken were analysed in relation to outcome of surgery.

Results
Of those who died, 45·7 per cent had intraoperative adverse events compared with 30·3 per cent in the cohort group. Major bleeding, gross spillage of faeces, and two or more intraoperative adverse events were more common among those who died. When the anastomosis was considered unsatisfactory, it was more frequently reconstructed (restapled or completely resutured), with or without a temporary stoma, in those who survived. The use of a temporary stoma was comparable in the two groups when adverse events were present.

Conclusion
Intraoperative adverse events were important contributors to morbidity and mortality. Complete reconstruction of an unsatisfactory anastomosis, with or without addition of a temporary stoma, was more frequently performed in the survivors, and may have diminished the risk of postoperative death.
Early impact of centralization of oesophageal cancer surgery services
Authors: Branagan G , Davies N 
Published: November 2004

Abstract

Background
In response to national guidance, oesophageal surgery from four hospitals within Wessex was centralized to a single site, with a provision for surgeons to travel to the centre to operate if they wished. This study assessed the clinical impact of this change.

Methods
Data for patients who had oesophageal cancer surgery at the single site were collected prospectively for 1 year from May 2002 and compared with the Wessex Oesophageal Cancer Audit (WOCA) data for the four hospitals from 1999 to 2000.

Results
Thirty-three patients underwent surgery on the single site compared with 40 patients from the four hospitals during the WOCA. Age, sex, co-morbidity, tumour site, and preoperative tumour and node stage were similar in the two groups. Six patients from the WOCA underwent ‘open and close’ laparotomy compared with none in the single-site group (P = 0·020). There were four anastomotic leaks in the WOCA group and two in the single-site group. Overall complication rates in those undergoing resection were similar in the two groups, but the in-hospital mortality rate was significantly higher in the WOCA group (five versus no patients; P = 0·022). Pathology reporting was incomplete in significantly more patients in the WOCA group (15 versus three; P = 0·001). The mean node harvest was greater in the single-site group (30·5 versus 19).

Conclusion
Centralization of oesophageal surgery resulted in better preoperative staging, a lower 30-day mortality rate and more complete pathological reporting.
Presentation, treatment and outcome in patients with ampullary tumours
Authors: Bettschart V , Rahman M Q , Engelken F J F , Madhavan K K , Parks R W , Garden O J 
Published: November 2004

Abstract

Background
Ampullary tumours are relatively rare, and few large single-centre reports provide information on their treatment and outcome. The aim of this study was to analyse outcome and determine predictors of survival for patients with ampullary tumours treated in a specialist centre.

Methods
Over an 11-year period, 561 patients were treated for periampullary tumours, 88 of whom had a histologically proven ampullary neoplasm. Prospectively gathered data were analysed to assess predictors of survival.

Results
The overall resection rate was 92 per cent; there were no postoperative deaths. Median survival was 45·8 months for patients with resectable tumours and 8·0 months for those with irresectable disease (P &lt; 0·001). On univariate analysis, age less than 70 years (P = 0·015) and a bilirubin level of 75 µmol/l or less (P = 0·012) favoured long-term survival. Among 70 patients who underwent cancer resection, factors associated with significantly worse long-term survival on univariate analysis included poorly differentiated tumour (P &lt; 0·001), positive nodes (P &lt; 0·001), perineural invasion (P = 0·001) and invasion of the pancreas (P = 0·018). Multivariate analysis identified positive nodes and bilirubin concentration as independent predictors of survival.

Conclusion
An aggressive surgical approach to ampullary tumours is justified by the low proportion of benign lesions, the absence of postoperative mortality and improved long-term survival.
Association of Cu2+with Uracil and Its Thio Derivatives: A Theoretical Study
Authors: Lamsabhi Al Mokhtar , Alcamí Manuel , Mó Otilia , Yáñez Manuel , Tortajada Jeanine 
Published: November 2004

AbstractThe structures and relative stabilities of the complexes between Cu2+and uracil, 2‐thiouracil, 4‐thiouracil, and 2,4‐dithiouracil were investigated by B3LYP/6‐311+G(2df,2p)//B3LYP/6‐31G* DFT calculations. In those systems in which both types of basic centers, that is, a carbonyl and a thiocarbonyl group, are present, association of Cu2+with the oxygen atom is systematically favored, in contrast to what was found for the corresponding Cu+complexes. This can be understood by considering that association of Cu2+is immediately followed by oxidation of the base, which accumulates the negative charge at the oxygen atoms. Similarly, for 2,4‐dithiouracil the most basic site for Cu+attachment is the sulfur atom at the 4‐position, while for association of Cu2+it is the sulfur atom at the 2‐position. In contrast, differences between uracil–Cu+and uracil–Cu2+complexes are very small, and in both cases the oxygen atom at the 4‐position is the most basic. Cu2+binding energies are about 4 and 1.2 times larger than Cu+binding energies and proton affinities, respectively. Uracil– and thiouracil–Cu2+complexes are thermodynamically unstable but kinetically stable with respect to their dissociation into uracil.++Cu+or thiouracil.++Cu+. The Cu2+binding energies vary with the difference between the second ionization potential of the metal and the first ionization potential of the base. regardless of the reference acid (H+, Cu+, Cu2+) the basicity trend is 2,4‐dithiouracil>4‐thiouracil>2‐thiouracil>uracil.
Role of pharmacogenomics in drug development
Authors: Hakonarsson Hakon , Stefansson Kari 
Published: November 2004

AbstractPharmacogenomics is charged with the task of uncovering genetic variations that underlie responses to drugs. While the results in the field have been slow in coming, more recent high‐throughput screening methods and data‐mining approaches are expected to effectively expedite the drug development process in the near future. While these new techniques are likely to reduce costs, the selection of the most pertinent study cohort with respect to the biological mechanism of the study compound is a critical element in risk management. Enrichment of the study cohort with carriers of “at‐risk” variants in genes that reside within and/or influence the biological pathway targeted by the drug candidate, would be expected to lower the risk of drug failure, while both delivering faster and better results at lower costs. In this context, at deCODE Genetics, Inc., the powerful coupling of family‐based linkage to ultra‐high throughput genotyping, gene array, and proteomics technology, together with innovative bioinformatic resources, provides a focused integrative strategy for pinpointing disease‐causing genes that may generate validated drug targets and genes that are responsible for differential response to drugs. deCODE has compiled one of the world's most comprehensive collection of population data on genealogy, genotypes, and phenotypes. This combination of resources provides an effective system for uncovering genes that predispose to disease or regulate drug response. In addition, this approach allows for the development of novel therapeutic strategies and diagnostic tests that, apart from being applicable to assessment of disease susceptibility and clinical response to drugs, provide for an effective clinical trial design, ultimately leading to safer and more efficacious drugs for patients. Drug Dev. Res. 62:86–96, 2004. © 2004 Wiley‐Liss, Inc.
Pharmacogenetics in drug development: Regulatory and clinical considerations
Authors: Hall Susan T. , Abbott Neil , Schmith Ginny , Brazell Celia 
Published: November 2004

AbstractPharmacogenetics (the study of inter‐individual inherited variations in DNA sequence related to drug response) is increasingly gaining recognition as an integral part of modern drug development and health care because it provides significant opportunities to increase the safety and efficacy of medicines. The challenge for the pharmaceutical industry and the regulators is exactly how and when to integrate pharmacogenetics to deliver on this potential. There are numerous aspects to consider when determining the data requirements for a regulatory submission to support labeling claims based on genotype. Regulators are committed to fostering a collaborative approach with key stakeholders to address the issues and to develop guidelines as judiciously as possible. It is recognized that pharmacogenetics research must be integrated into an appropriate regulatory framework that does not stifle development of the science nor the applications that will benefit patients. Dialogue, together with a willingness to share experiences of pharmacogenetics in drug development, is critical to moving forward. Drug Dev. Res. 62:102–111, 2004. © 2004 Wiley‐Liss, Inc.
Pharmacogenomics, drug development, and ethics: Some points to consider
Authors: Lunshof Jeantine , de Wert Guido 
Published: November 2004

AbstractPharmacogenomics will contribute in the near future to significant changes in drug delivery and drug development. In both areas, the application of pharmacogenomics gives rise to ethical, legal, and social concerns. These concerns have recently been addressed by various national and international working groups. In this article, we will give a concise overview of the ethical issues raised in particular by the application of pharmacogenomics in the context of drug development. Taking a basic approach, we will show the cumulative development of ethical issues in clinical research, medical genetics, and in pharmacogenomics with special focus on drug development. The relevance of “genetic exceptionalism” will be scrutinized with regard to its impact on questions concerning stratification in particular. To this end, we will refer to the views expressed in documents by various expert working groups and to the recent recommendations made by international organizations. We will show which points to consider arise specifically in the context of pharmacogenomics in addition to the known issues covered by the established guidelines on ethical, legal, and social aspects of clinical research and genetics. Drug Dev. Res. 62:112–116, 2004. © 2004 Wiley‐Liss, Inc.
Resolution of cellular physiology by genomic expression signature analysis: Bridging the content gap between in vitro and in vivo drug development
Authors: Gunther Erik C. , Gerwien Robert W. 
Published: November 2004

AbstractGenomic expression profiling provides a high‐content means of characterizing the physiological action of drugs at the cellular systems biology level. By recognizing the distinct gene expression patterns that characterize various cellular states, it is possible to classify unknown drug treatments by the therapeutically relevant physiology they induce. Because the range of cellular physiologies is wide, and the resolution of expression profiling is comprehensive, this pattern recognition–based approach represents a generic means of drug action analysis and prediction. Drug candidate efficacy, specificity, and toxicity can be determined early in drug development, streamlining a process currently fraught with costly attrition and deficient in generating mechanistically new therapeutics. Drug Dev. Res. 62:119–123, 2004. © 2004 Wiley‐Liss, Inc.