bluuebunny/crossref_metadata_2025 huggingface dataset:
Analysis of estrogens in sediment from a sewage-impacted urban estuary using high-performance liquid chromatography/time-of-flight mass spectrometry
Authors: Reddy Sharanya , Brownawell Bruce J.
Published: April 2005

We describe a highly selective and sensitive method for determination of estrone (E1) and β-estradiol (E2) in sediments, using high-performance liquid chromatography/time-of-flight (HPLC-ToF) mass spectrometry. The method involved sequential cleanup of sediment extracts over solid phase extraction cartridges, normal phase HPLC, and immunoaffinity extraction, which combine to remove coeluting matrix interferences. Resulting method detection limits (0.03 and 0.04 ng/g for E1 and E2, respectively) are sufficient to determine E1 and E2 in estuarine sediments collected from sewage-impacted Jamaica Bay (New York, NY, USA). The ToF analyzer has a higher resolution (>6,000) than quadrupole mass analyzers and can provide accurate mass estimation to within 2 mDa, which helped in distinguishing steroids from isobaric matrix interferences. The E1 and E2 were internally mass calibrated with respect to their coeluting surrogate standards, and the mass measurement error was between 1.1 and 1.4 mDa. The levels of E1 and E2 ranged between 0.07 to 2.52 and 0.05 to 0.53 ng/g, respectively. The measured concentrations of steroids in sediments correlated closely with other wastewater tracers. Despite the low concentrations of sediment-associated estrogens, their predicted estrogenic potency exceeds that of other measured estrogenic contaminants.
Population-level effects of male-biased broods in eelpout (Zoarces viviparus)
Authors: Hanson Niklas , Åberg Per , Sundelöf Andreas
Published: April 2005

Effects of environmental pollutants are most obvious when mortality is increased. However, there are other nonlethal factors that may affect population size significantly. Endocrine disruption as a mechanism of action for pollutants recently has received much attention. Observations of effects likely caused by endocrine disruptors in pulp mill effluents have been made on several fish species, e.g., male-biased broods in eelpout (Zoarces viviparus). Fewer females represent a lower fecundity and could have dramatic effects on the population. In this study, a population viability analysis of the effects of skewed primary sex ratios in the eelpout was conducted using a female-based matrix population model. The model is age-structured with one deterministic version and another that incorporates environmental stochasticity. The model showed that the deterministic and stochastic growth rates in an undisturbed population (50% female fry) were 1.172 and 1.075, respectively, compared to 1.097 and 1.007 using the lowest proportion of female fry observed (38.7%). When primary sex ratios were more male-biased, the probability of pseudoextinction increased. Model simulations showed that the probability of a decreased population size to 5% of the initial within a 100-year time horizon was 44.7% with 38.7% female fry compared to only 7.7% for an undisturbed population.
Influences of maternal exposure on the tolerance and physiological performance of Daphnia magna under mercury stress
Authors: Tsui Martin T.K. , Wang Wen-Xiong
Published: April 2005

We examined the tolerance development to mercury (Hg) by a population of freshwater zooplankton (Daphnia magna) with different pre-exposure histories to Hg. The growth and reproductive performance of the F1 offspring as affected by the maternal (F0) and offspring (F1) exposures was quantified. The Fo daphnids exposed to 2.5 and 25 nM of Hg for 4 d and followed by 4 d of depuration had elevated levels of Hg and metallothionein-like proteins (MTLPs), as well as higher tolerance to Hg toxicity than the control daphnids. The higher Hg tolerance may be attributed to the higher proportion of Hg partitioned to the MTLPs. Moreover, significant enhancement of Hg tolerance also was found in the F1 offspring originating from the F0 mothers exposed to 25 nM of Hg, but there was no significant induction of MTLPs in these F1 offspring when compared to the offspring from the control mothers. The Hg tissue concentrations in the F1 neonates were approximately 25% of those in the F0 adults. However, there was similar Hg tolerance in the F2 offspring originating from both the control and Hg-exposed F0 mothers, indicating that the Hg tolerance in the daphnids disappeared two generations after Hg contamination. Further exposure of the F1 offspring to different Hg concentrations (1.5 and 15 nM for 28 d) indicated that maternal exposure history did not affect their growth and reproductive performance, which solely were influenced by the offspring exposure. Unexpectedly, the F1 offspring exposed to Hg had significantly higher final wet weights and reproductive rates than the control groups, suggesting the possibility of Hg hormesis. Furthermore, the maternal exposure had no effect on the Hg accumulation and the MTLP concentrations in the F1 offspring. Therefore, we concluded that the Hg tolerance might disappear quickly once the Hg contamination was removed and the maternal exposure history was not important in determining the physiological performance and Hg accumulation of the subsequent generations.
Association between lymphocyte proliferation and polychlorinated biphenyls in free-ranging harbor seal (Phoca vitulina) pups from British Columbia, Canada
Authors: Levin Milton , De Guise Sylvain , Ross Peter S.
Published: April 2005

Recent pinniped die-offs have led to the speculation that persistent organic pollutants (POPs) are immunomodulatory, making individuals more susceptible to viral infections. Eighteen healthy harbor seal (Phoca vitulina) pups (aged 3–4 weeks) were live-captured from southern British Columbia, Canada, and maintained temporarily in captivity for an immunotoxicological assessment. The relationships between mitogen-induced peripheral blood lymphocyte proliferation and blubber concentrations of three major immunotoxic POP classes (the polychlorinated biphenyls [PCBs], polychlorinated dibenzo-p-dioxins [PCDDs], and the polychlorinated dibenzofurans [PCDFs]) were evaluated. A significant body weight-independent positive correlation was observed between both T-cell mitogen (phytohemagglutinin [PHA])- and B-cell mitogen (lipopolysaccharide [LPS])-induced lymphocyte proliferation and the blubber concentrations of total PCB. Best subset regression analysis revealed that total PCBs, and not total PCDD or total PCDF, explained 24 and 29% of the changes in both T-cell mitogen-and B-cell mitogen-induced lymphocyte proliferation, respectively. Further regression analysis performed on the PCB classes measured in this study showed that di-ortho PCBs accounted for 25 and 30% of the changes in both T-cell and B-cell lymphocyte proliferation, respectively. Results suggest that POPs, and PCBs in particular, are associated with changes in lymphocyte proliferation, something that could result in increased susceptibility to infections in harbor seal pups. Further research is needed to evaluate the relative roles of natural and contaminant-related influences on the immune system of marine mammals.
Influence of sediment quality on the responses of benthic invertebrates after treatment with the fungicide triphenyltin acetate
Authors: De Haas Elske M. , Roessink Ivo , Verbree Bets , Koelmans Albert A. , Kraak Michiel H.S. , Admiraal Wim
Published: April 2005

After decades of pollution, benthic communities in floodplain lake ecosystems are likely to be exposed to a diverse assortment of sediment-bound historical toxicants and nutrients as well as pulses of newly discharged or deposited toxicants. The aim of this study was therefore to analyze the effects of background sediment pollution on the responses of benthic invertebrates to an experimental toxic shock in a laboratory setting. Sediment from a relatively clean and a historically polluted floodplain lake located along the River Waal, a branch of the River Rhine, The Netherlands, was selected, and the fungicide triphenyltin acetate (TPT) was used as the acute stressor. Juvenile stages of the mayfly Ephoron virgo and the midge Chironomus riparius were chosen as test organisms because of their different response to sediment-bound toxicants and food quantity and quality. Our results demonstrated that the type of sediment had no effect on survival and growth of C. riparius when exposed to sediment-associated TPT and that E. virgo was more affected by sediment-associated TPT on clean sediment than on polluted sediment. For the mayfly, no cumulative response of the historical pollution and the recent toxic shock was observed. This observation is discussed in view of the variable content of organic matter, acting both as food and as sorbent, and leads to the hypothesis that a very strong sequestering of TPT in historically polluted sediment prevents expression of toxic effects.
Influence of duration of exposure to the pyrethroid fenvalerate on sublethal responses and recovery of Daphnia magna straus
Authors: Reynaldi Sebastián , Liess Matthias
Published: April 2005

This study compares lethal and sublethal responses of Daphnia magna Straus exposed to fenvalerate continuously (21 d) and as a pulse (24 h). Survival was reduced more severely in the continuous- than in the pulse-exposure regime. Complete mortality occurred at 1 μg/L for continuous exposure and at 3.2 μg/L for pulse exposure. Regarding reproductive endpoints, fenvalerate delayed the age at first reproduction. At the beginning of the reproductive phase (day 10), this delay resulted in a reduction of the neonates per living female at similar concentrations in both exposure regimes (0.3 and 0.1 μg/L for continuous and pulse exposure, respectively). The population growth rate was inhibited in continuous and pulse exposure at 0.3 and 0.6 μg/L, respectively. However, the effects of fenvalerate in the pulse exposure were transient. After 21 d, a recovery to values close to the controls occurred with respect to the total neonates per female and the population growth rate over a broad range of concentrations from 0.1 up to 1 μg/L. In contrast, no substantial recovery occurred in the continuous-exposure regime.
Effect of urea on degradation of terbuthylazine in soil
Authors: Caracciolo Anna Barra , Giuliano Giuseppe , Grenni Paola , Cremisini Carlo , Ciccoli Roberto , Ubaldi Carla
Published: April 2005

Pesticide and nitrate contamination of soil and groundwater from agriculture is an environmental and public health concern worldwide. The herbicide terbuthylazine (CBET) has replaced atrazine in Italy and in many other countries because the use of the latter has been banned because of its adverse environmental impacts. Unlike atrazine, knowledge about the fate of CBET in soil is still not extensive, especially regarding its transformation products, but recent monitoring data show its occurrence and that of its main metabolite, desethyl-terbuthylazine (CBAT), in groundwater above the limit of 0.1μg/L established by European Union Directive and Italian legislation. The objective of this work was to investigate if the presence of the fertilizer urea affects CBET degradation in the soil. Laboratory CBET degradation experiments in the presence/absence of urea were performed with microbiologically active soil and sterilized soil. Terbuthylazine degradation rates under the different experimental conditions were assessed, and the formation, degradation, and transformation of the metabolite CBAT were also studied. Terbuthylazine degradation was affected by the presence of urea, in terms both of a higher disappearance time of 50% of the initial concentration and of a lower amount of CBAT formed. These findings have practical implications for the real-life assessment of the environmental fate of triazine herbicides in agricultural areas since these herbicides are frequently applied to soils receiving ureic fertilizers.
Joint effects of density and a growth inhibitor on the life history and population growth rate of the midge Chironomus riparius
Authors: Hooper Helen L. , Sibly Richard M. , Hutchinson Thomas H. , Maund Stephen J.
Published: April 2005

Results of previous laboratory studies suggest that high population density often buffers the effects of chemical stressors that predominately increase mortality. Mortality stressors act to release more resources for the survivors and, therefore, produce less-than-additive effects. By contrast, growth stressors are expected to have opposite results or more-than-additive effects. We investigated the effects of a growth inhibitor (lufenuron) on larval growth and survival of Chironomus riparius and examined its joint effects with density on population growth rate (PGR). Exposure to 60 μg/kg sediment or greater inhibited larval growth, and exposure to 88 μg/kg or greater often resulted in mortality before reaching emergence. The effects of lufenuron, however, differed with population density. At 88 μg/kg, mortalities and, to a lesser extent, reduced fecundity resulted in a reduction in PGR at low density. Conversely, when populations were initiated at high density, PGR was similar to that of controls, because the few survivors reached maturity sooner and started producing offspring earlier. The effect of density as a growth stressor therefore was stronger than the effect of lufenuron, which had effects similar to those of a mortality stressor and produced less-than-additive effects. Long-term studies under field conditions, however, are needed before less-than-additive effects are considered to be the norm.
Acute contamination with esfenvalerate and food limitation: Chronic effects on the mayfly, Cloeon dipterum
Authors: Beketov Mikhail A. , Liess Matthias
Published: April 2005

Results of environmental risk assessments based merely on toxic effects of contaminants at the individual level, without consideration of population-level effects, may be questionable. The aim of the present study was to investigate how limited food resources, resulting in intraspecific competition, could interact with the chronic effect of short-term contamination with the insecticide esfenvalerate. Larvae of the mayfly, Cloeon dipterum, were exposed to esfenvalerate (0.001–100 μg/L) for 1 h and then transferred to indoor microcosms containing insecticide-free water, where they were maintained at various food levels until emergence. The results showed that short-term exposure to 10 or 100 μg/L resulted in acute mortality. Chronic effects on survival occurred at concentrations up to three orders of magnitude lower than that causing the acute effect (0.01 μg/L). Food limitation increased effects on organisms during medium-term observation (8–15 d), but assessment of long-term survival rates suggested that the chronic effects of low insecticide concentrations could be compensated for, at least regarding some endpoints. The authors assume that in limited-food conditions, lethal and sublethal effects reduced competition between individuals, resulting in significantly increased final survival.
Acute and chronic toxicity of mercury to early life stages of the rainbow mussel, Villosa iris (Bivalvia: Unionidae)
Authors: Valenti Theodore W. , Cherry Donald S. , Neves Richard J. , Schmerfeld John
Published: April 2005

Mercury (Hg) contamination is receiving increased attention globally because of human health and environmental concerns. Few laboratory studies have examined the toxicity of Hg on early life stages of freshwater mussels, despite evidence that glochidia and juvenile life stages are more sensitive to contaminants than adults. Three bioassays (72-h acute glochidia, 96-h acute juvenile, and 21-d chronic juvenile toxicity tests) were conducted by exposing Villosa iris to mercuric chloride salt (HgCl2). Glochidia were more sensitive to acute exposure than were juvenile mussels, as 24-, 48-, and 72-h median lethal concentration values (LC50) for glochidia were >107, 39, and 14 μg Hg/L, respectively. The 24-, 48-, 72-, and 96-h values for juveniles were 162, 135, 114, and 99 μg Hg/L, respectively. In the chronic test, juveniles exposed to Hg treatments ≥8 μg/L grew significantly less than did control organisms. The substantial difference in juvenile test endpoints emphasizes the importance of assessing chronic exposure and sublethal effects. Overall, our study supports the use of glochidia as a surrogate life stage for juveniles in acute toxicity tests. However, as glochidia may be used only in short-term tests, it is imperative that an integrated approach be taken when assessing risk to freshwater mussels, as their unique life history is atypical of standard test organisms. Therefore, we strongly advocate the use of both glochidia and juvenile life stages for risk assessment.
RNA/DNA ratios as a sublethal endpoint for large-scale toxicity tests with the nematode Caenorhabditis elegans
Authors: Ibiam Udu , Grant Alastair
Published: April 2005

Caenorhabditis elegans increasingly is attractive as a toxicity test organism, particularly as a model system to study mechanisms of toxicity at a molecular level and the way that these lead to whole organism and population level effects. Inhibitions of growth, reproduction, movement, and feeding rate all have been proposed as sublethal toxicity endpoints. These endpoints are more sensitive than 24-h acute toxicity endpoints, but assays are much more time consuming, making them difficult to use in mass screening. The RNA/DNA ratio, after 48-h exposure to metals, has median effective concentration (EC50) values of 0.05, 0.6, 6.1, and 35 mg/L for Cu, Pb, Cd, and Zn, respectively. This makes it a slightly more sensitive toxicity endpoint than reduction of individual growth after 72-h exposure to the same concentrations. This facilitates the near-simultaneous assessment of sublethal toxicity in many nematode samples. The constant cell number of C. elegans means that different stages in the life history have very different RNA/DNA ratios even in the absence of toxins. So, RNA/DNA ratios can be used only on prereproductive, age-synchronized cultures. Assessing the sublethal toxicity of metals to C. elegans shows that it is sensitive particularly to Cu.
Sorption of benzidine and 3,3′-dichlorobenzidine to lake sediments. 1. conceptualization and development of a multiparameter model
Authors: Donaldson Francis P. , Nyman Marianne C.
Published: April 2005

Aromatic amines, such as benzidine and 3,3′-dichlorobenzidine (DCB), are part of the dyes and pigments manufacturing process. The prolonged use of these carcinogenic chemicals in the past generation has introduced a significant amount of contamination to the environment. Their persistency in several mediums has sparked a number of studies in an attempt to develop predictive tools of their fate and transport in the environment. In this study, benzidine and DCB batch isotherms were developed and evaluated. The sediment samples were variable in composition, ranging from sandy to silty-clay sediment samples. The batch isotherms were then analyzed using high-performance liquid chromatography. Subsequently, a multiparameter model (MPM) that accounted for partitioning, covalent bonding, and cation exchange was developed and tested in an effort to understand the various mechanisms. Results proved the proposed model to be effective in predicting sorption of aromatic amines to lake sediments. The findings suggest that the MPM can provide a better understanding of the sorption process of aromatic amines than more conventional models.
Novel biomarkers of perchlorate exposure in zebrafish
Authors: Mukhi Sandeep , Carr James A. , Anderson Todd A. , Patiño Reynaldo
Published: April 2005

Perchlorate inhibits iodide uptake by thyroid follicles and lowers thyroid hormone production. Although several effects of perchlorate on the thyroid system have been reported, the utility of these pathologies as markers of environmental perchlorate exposures has not been adequately assessed. The present study examined time-course and concentration-dependent effects of perchlorate on thyroid follicle hypertrophy, colloid depletion, and angiogenesis; alterations in whole-body thyroxine (T4) levels; and somatic growth and condition factor of subadult and adult zebrafish. Changes in the intensity of the colloidal T4 ring previously observed in zebrafish also were examined immunohistochemically. Three-month-old zebrafish were exposed to ammonium perchlorate at measured perchlorate concentrations of 0, 11, 90, 1,131, and 11,480 ppb for 12 weeks and allowed to recover in clean water for 12 weeks. At two weeks of exposure, the lowest-observed-effective concentrations (LOECs) of perchlorate that induced angiogenesis and depressed the intensity of colloidal T4 ring were 90 and 1,131 ppb, respectively; other parameters were not affected (whole-body T4 was not determined at this time). At 12 weeks of exposure, LOECs for colloid depletion, hypertrophy, angiogenesis, and colloidal T4 ring were 11,480, 1,131, 90, and 11 ppb, respectively. All changes were reversible, but residual effects on angiogenesis and colloidal T4 ring intensity were still present after 12 weeks of recovery (LOEC, 11,480 ppb). Whole-body T4 concentration, body growth (length and weight), and condition factor were not affected by perchlorate. The sensitivity and longevity of changes in colloidal T4 ring intensity and angiogenesis suggest their usefulness as novel markers of perchlorate exposure. The 12-week LOEC for colloidal T4 ring is the lowest reported for any perchlorate biomarker in aquatic vertebrates.
Toxicity of α-, β-, (α+β)-endosulfan and their formulated and degradation products to Daphnia magna, Hyalella azteca, Oncophynchus mykiss, Oncophynchus kisutch, and biological implications in streams
Authors: Wan Michael T. , Kuo Jen-Ni , Buday Craig , Schroeder Grant , Van Aggelen Graham , Pasternak John
Published: April 2005

The static acute toxicities of α-endosulfan, β-endosulfan, (α + β)-endosulfan, endosulfan sulfate (their transformation product), and formulated materials were determined for a representative freshwater amphipod (Hyalella azteca), cladoceran (Daphnia magna), and salmonid fish (Oncorhynchus mykiss). Acute lethality tests also were conducted on these organisms and coho salmon (Oncorhynchus kisutch) by exposing them to simulated field water endosulfan concentrations, using either a single compound and/or in combinations. As well, growth/survival bioassays of H. azteca were carried out in simulated sediment endosulfan concentrations that were detected in farm ditches contiguous to fish streams in the Lower Fraser Valley (BC, Canada). All materials tested were very highly toxic to these nontarget aquatic indicator organisms. As the most potent compound, α-endosulfan is about 1.3, 6.6, and 58 times more toxic than the β-isomer to Daphnia, rainbow trout, and Hyalella, respectively. Some possible biological and toxicological implications of our findings are discussed in the context of endosulfan concentrations found in farm ditches flowing to fish streams in the Lower Fraser Valley.
Potentiation of the vitellogenic response to 17α-ethinylestradiol by cortisol in the fathead minnow Pimephales promelas
Authors: Brodeur Julie C. , Woodburn Kent B. , Klecka Gary M.
Published: April 2005

The effects of elevated plasma Cortisol levels on vitellogenin (VTG) induction were examined in the fathead minnow (Pimephales promelas) in an attempt to evaluate the potential influence of stress on this commonly used biomarker of estrogenicity. Two separate experiments were conducted in which fish plasma cortisol was elevated to various levels for 14 d by noninvasive additions of cortisol to the aquaria water. Fathead minnows were exposed to either cortisol alone, 17α-ethinylestradiol (EE2) alone, or a combination of the two hormones, and plasma levels of VTG as well as liver expression of VTG mRNA were measured. Both experiments gave similar results, with an exposure to 4 ng/L of EE2 resulting in significantly greater levels of plasma VTG in the presence of, compared to that in absence of, cortisol, whereas exposure to cortisol alone at concentrations between 144 and 800 μg/L had no effect on plasma VTG levels. This potentiation of the EE2-induced vitellogenesis by cortisol was dose-dependent, with plasma VTG reaching 125, 167, and 295% of the values obtained with EE2 alone when 144, 360, and 800 μg/L of cortisol, respectively, were added to the water. Liver mRNA results were consistent with plasma VTG, although they generally were more variable. The present study demonstrates that cortisol does not independently induce vitellogenesis but can potentiate estrogen-induced VTG synthesis in fathead minnow. The implications of these findings for the use of VTG as a biomarker of estrogenicity are discussed.
Multiple sublethal chemicals negatively affect tadpoles of the green frog, Rana clamitans
Authors: Boone Michelle D. , Bridges Christine M. , Fairchild James F. , Little Edward E.
Published: April 2005

Many habitats may be exposed to multiple chemical contaminants, particularly in agricultural areas where fertilizer and pesticide use are common; however, the singular and interactive effects of contaminants are not well understood. The objective of our study was to examine how realistic, sublethal environmental levels of ammonium nitrate fertilizer (0, 10, 20 mg/L and ammonium chloride control) and the common insecticide carbaryl (0 or 2.5 mg/L) individually and interactively affect the development, size, and survival of green frog (Rana clamitans) tadpoles. We reared tadpoles for 95 d in outdoor 1,000-L polyethylene ponds. We found that the combination of carbaryl and nitrate had a negative effect on development and mass of tadpoles compared to the positive effect that either contaminant had alone. Presence of carbaryl was generally associated with short-term increases in algal resources, including ponds exposed to both carbaryl and nitrate. However, with exposure to nitrate and carbaryl, tadpole mass and development were not positively affected as with one chemical stressor alone. The combination of these sublethal contaminants may reduce the ability of amphibians to benefit from food-rich environments or have metabolic costs. Our study demonstrates the importance of considering multiple stressors when evaluating population-level responses.
Comparative toxicity of two oil dispersants, superdispersant-25 and corexit 9527, to a range of coastal species
Authors: Scarlett Alan , Galloway Tamara S. , Canty Martin , Smith Emma L. , Nilsson Johanna , Rowland Steven J.
Published: April 2005

The acute toxicity of the oil dispersant Corexit 9527 reported in the literature is highly variable. No peer-reviewed data exist for Superdispersant-25 (SD-25). This study compares the toxicity of the two dispersants to a range of marine species representing different phyla occupying a wide range of niches: The marine sediment-dwelling amphipod Corophium volutator (Pallas), the common mussel Mytilus edulis (L.), the symbiotic snakelocks anemone Anemonia viridis (Forskål), and the seagrass Zostera marina (L.). Organisms were exposed to static dispersant concentrations for 48-h and median lethal concentration (LC50), median effect concentration (EC50), and lowest-observable-effect concentration (LOEC) values obtained. The sublethal effects of 48-h exposures and the ability of species to recover for up to 72 h after exposure were quantified relative to the 48-h endpoints. Results indicated that the anemone lethality test was the most sensitive with LOECs of 20 ppm followed by mussel feeding rate, seagrass photosynthetic index and amphipod lethality, with mussel lethality being the least sensitive with LOECs of 250 ppm for both dispersants. The results were consistent with current theory that dispersants act physically and irreversibly on the respiratory organs and reversibly, depending on exposure time, on the nervous system. Superdispersant-25 was found overall to be less toxic than Corexit 9527 and its sublethal effects more likely to be reversible following short-term exposure.
Uptake and accumulation of sediment-associated 4-nonylphenol in a benthic invertebrate (Lumbriculus variegatus, freshwater oligochaete)
Authors: Croce Valeria , De Angelis Silvia , Patrolecco Luisa , Polesello Stefano , Valsecchi Sara
Published: April 2005

In the present work, the oligochaete Lumbriculus variegatus was exposed for 56 d to lake sediment spiked with 4-nonylphenol (4-NP), which is a breakdown product of alkylphenol polyethoxylates, an important class of nonionic surfactants. During the exposure period, the content of 4-NP was determined in the oligochaetes, sediment, overlying water, and pore water in order to monitor the distribution of the 4-NP in the compartments of the test system. Concentration of 4-NP in L. variegatus increased linearly over the course of the test, with an uptake rate coefficient of 1.9 × 10−2 (± 0.2 × 10−2; [g carbon/(g lipid-h)]). No steady state was reached at the end of the exposure period, suggesting that the elimination of 4-NP by the organism was negligible. Ingested sediments played an important role in the accumulation of 4-NP in L. variegatus, which may achieve very high 4-NP body concentrations. The 56-d biota sediment accumulation factor (BSAF) was 24 ± 7 g carbon/g lipid. L. variegatus also was exposed to 4-NP-contaminated field sediment, and field oligochaetes and sediments were collected for 4-NP pollution assessment in aquatic ecosystem. The 4-NP uptake with natural sediment was in accordance with that measured with spiked sediments, suggesting that the bioavailability of sediment-associated 4-NP for L. variegatus was not affected by 4-NP sediment concentration and abiotic sediment characteristics. The BSAFs measured in field oligochaetes, ranging from 39 to 55 g carbon/g lipid, was relatively higher than the bioaccumulation factor measured in laboratory tests. The results suggest that 4-NP concentration can reach high levels in benthic oligochaetes; this can be an important way of exposure for their pelagic predators.
An in vitro study of the interaction of sea-nine® with rat liver mitochondria
Authors: Bragadin Marcantonio , Pavoni Bruno , Scutari Guido , Manente Sabrina
Published: April 2005

The interactions of the antifouling compound Sea-Nine® with rat liver mitochondria have been studied. The results indicate that low doses of this compound inhibit adenosine 5′-triphosphate (ATP) synthesis. Further investigations indicate that ATP synthesis inhibition should be due to an interaction of Sea-Nine with the succinic dehydrogenase in the mitochondrial respiratory chain.
Effects of bioturbation on cadmium transfer and distribution into freshwater sediments
Authors: Ciutat Aurélie , Anschutz Pierre , Gerino Magali , Boudou Alain
Published: April 2005

To investigate bioturbation effects on cadmium (Cd) fluxes from overlying water to sediments, indoor microcosms were developed. The bioturbating organisms were freshwater tubificid worms. Three experimental conditions were studied during 56 d. The three conditions were contaminated water column ([Cd]: 20 μg/L) with or without worms and uncontaminated water column with worms. Cadmium vertical profiles were determined in the pore water and in the sediments, based on six layers (0–0.5, 0.5–1, 1–2, 2–3, 3–5, 5–12 cm). Dissolved oxygen, manganese, sulfate, and particulate manganese were measured. Bioturbation was analyzed using conservative fluorescent particulate tracers. Bioturbation increased Cd flux into the sediments by close to a factor of two. Scavenging of Cd was more efficient in the bioturbated sediments because particles and adsorption sites for Cd were renewed at the sediment-water interface. Tubificids also increased the thickness of the Cd-enriched layer. Metals adsorbed on particles at the sediment surface were distributed by bioadvection, which predominated the mixing processes. Bioturbation also modified the vertical profiles of dissolved and particulate manganese and dissolved sulfate but not the profiles of dissolved oxygen. These results indicate that the advective transport of particles by bioturbation and their subsequent modification by redox reactions accelerates the trapping of metals in sediments.
Ecotoxicity of sodium fluoroacetate (compound 1080) to soil organisms
Authors: O'Halloran Kathryn , Jones Denise , Booth Lynn , Fisher Penny
Published: April 2005

Sodium fluoroacetate (compound 1080) is applied as a vertebrate pesticide in New Zealand for control of introduced mammalian pests. Despite its widespread use, little is known about the soil ecotoxicity of 1080. Therefore, the hazard of 1080 to soil invertebrates, plants, and soil microorganisms was evaluated in a series of controlled laboratory tests. No earthworm (Eisenia fetida) mortality was reported with 1080 exposures up to 865 mg/kg soil. The lowest-observable-effect concentration and the median effect level for earthworm reproduction were 100 and 90 mg/kg soil, respectively, for cocoon production and 100 and 160 mg/kg soil, respectively, for juvenile production. Lettuce (Lactuca sativa) was more sensitive than oats (Avena sativa) to 1080. Lettuce seedling emergence and seedling shoot growth were adversely affected at a soil concentration of 7 mg/kg. The presence of 1080 in soil at concentrations up to 1 g/kg soil did not affect the ability of soil microorganisms to mineralize nitrogen. Furthermore, nitrate mineralization was not inhibited in soil treated with the urine of 1080-poisoned possums (Trichosurus vulpecula). The data collectively indicate that 1080-related effects on soil organisms occur at levels well above those that have been measured in soil (<0.1 mg/kg) following application of 1080 in baits for vertebrate pest control in New Zealand.
New Trends in the Use of Transition Metal–Ligand Complexes for Applications in Electroluminescent Devices
Authors: Holder E. , Langeveld B. M. W. , Schubert U. S.
Published: April 2005

The advantage of using phosphorescent transition metal–ligand complexes in optoelectronic applications such as organic light‐emitting diodes (OLEDs) and light‐emitting electrochemical cells (LECs) are described and evaluated. Additionally, different device constructions utilizing phosphorescent transition‐metal complexes like iridium(III) mixed‐ligand complexes and ruthenium(II) systems are reviewed and specified. Diverse host materials in which the phosphorescent emitters can be placed are discussed, such as small organic molecules and a few polymeric systems, and alternative processing technologies are briefly compared. Recent developments in the synthesis of iridium(III) triplet emitters are discussed. Different device architectures require different kinds of metal–ligand complexes. The different synthetic routes leading to charged and non‐charged complexes are briefly discussed.
Cover Picture: Nanohybrid Shish‐Kebabs: Periodically Functionalized Carbon Nanotubes (Adv. Mater. 9/2005)
Authors: Li C. Y. , Li L. , Cai W. , Kodjie S. L. , Tenneti K. K.
Published: April 2005

Carbon nanotube (CNT)‐seeded controlled polymer crystallization provides a simple yet effective means to periodically modify CNT surfaces in work reported by Li and co‐workers on p. 1198. The cover shows CNTs periodically decorated with polyethylene single crystals, with a periodicity of ∼50–70  nm. Both single‐ and multiwalled CNTs have been successfully decorated with polyethylene and Nylon 6,6, implying that coupling crystalline polymers with functional groups might be a generic method for CNT functionalization in an ordered and controlled manner.
Inside Front Cover: Nanoparticle Self‐Assembly of Hierarchically Ordered Microcapsule Structures (Adv. Mater. 9/2005)
Authors: Rana R. K. , Murthy V. S. , Yu J. , Wong M. S.
Published: April 2005

Nanoparticle (NP)‐assembled microcapsules represent a new class of hollow‐sphere material, in which materials properties can be ‘programmed’ by way of NP and polymer compositions. Synthesis is based on a sequential self‐assembly of NPs and polymer macromolecules. Reported by Wong and co‐workers on p. 1145, this rapid, green synthesis technique applies to a wide spectrum of colloidal species and permits non‐destructive encapsulation of water‐soluble compounds. The inside cover shows a confocal microscopy image of water‐filled microcapsules composed of silica NPs and a fluorescence‐labelled polymer. The scale bar is 20  μm. The inset shows a simplified illustration of the microcapsule assembly process.
Minimum energy diagrams for multieffect distillation arrangements
Authors: Engelien Hilde K. , Skogestad Sigurd
Published: April 2005

The minimum energy requirements of six different heat‐integrated multieffect and three nonintegrated distillation arrangements for separating a ternary mixture have been considered. The focus is on a heat‐integrated complex distillation configuration, called a multieffect prefractionator arrangement. The comparison of the different arrangements is based on the minimum vapor flow rates at infinite number of stages, which are easily visualized and compared in a Vmin diagram. This tool can be used as a basis for screening and the best arrangement(s) can be studied further using more rigorous simulation methods. © 2005 American Institute of Chemical Engineers AIChE J, 2005
Genetic linkage of autosomal dominant progressive supranuclear palsy to 1q31.1
Authors: Ros Raquel , Gómez Garre Pilar , Hirano Michio , Tai Yen F. , Ampuero Israel , Vidal Lídice , Rojo Ana , Fontan Aurora , Vazquez Ana , Fanjul Samira , Hernandez Jaime , Cantarero Susana , Hoenicka Janet , Jones Alison , Ahsan R. Laila , Pavese Nicola , Piccini Paola , Brooks David J. , Perez‐Tur Jordi , Nyggard Torbjorn , de Yébenes Justo G.
Published: April 2005

Progressive supranuclear palsy (PSP) is a disorder of unknown pathogenesis. Familial clusters of PSP have been reported related to mutations of protein tau. We report the linkage of a large Spanish family with typical autosomal dominant PSP to a new locus in chromosome 1. Four members of this family had typical PSP, confirmed by neuropathology in one case. At least five ancestors had similar disease. Other members of the family have incomplete phenotypes. The power of the linkage analysis was increased by detecting presymptomatic individuals with 18F‐fluoro‐dopa and 18F‐deoxyglucose positron emission tomography. We screened the human genome with 340 polymorphic markers and we enriched the areas of interest with additional markers. The disease status was defined according to the clinical and positron emission tomography data. We excluded linkage to the tau gene in chromosome 17. PSP was linked, in this family, to one area of 3.4cM in chromosome 1q31.1, with a maximal multipoint < OD score of +3.53. This area contains at least three genes, whose relevance in PSP is unknown. We expect to further define the gene responsible for PSP, which could help to understand the pathogenesis of this disease and to design effective treatment. Ann Neurol 2005;57:634–641
Is freezing of gait in Parkinson's disease related to asymmetric motor function?
Authors: Plotnik Meir , Giladi Nir , Balash Yacov , Peretz Chava , Hausdorff Jeffrey M.
Published: April 2005

Freezing of gait (FOG) is a disabling phenomenon common in patients with advanced Parkinson's disease (PD). The cause of FOG is unclear. The objective of this study was to explore a novel hypothesis stating that FOG is related to asymmetric motor performance. We compared PD patients that experience FOG episodes (PD+FOG) with PD patients that do not (PD−FOG) and studied the relationship of FOG to asymmetry in gait and in rhythmic hand movement performance to determine whether potential FOG‐related gait asymmetry is unique to walking or whether it is systemic. Subjects were tested in an “off” (unmedicated) and again in an “on” (medicated) state. Gait was more asymmetric in PD+FOG than in PD−FOG during “off” state (p = 0.005) and during “on” (p = 0.016). Rhythmicity of foot swing in one leg was correlated with the other leg in PD−FOG but not in PD+FOG. There was no difference in asymmetry in performance of rhythmic hand movements between the two groups. No correlation was found between asymmetry of clinical symptoms and gait asymmetry. Taken together, the results of this study suggest that bilateral uncoordinated gait and marked gait asymmetry, but not asymmetry in motor performance in general, are associated with FOG. Ann Neurol 2005;57:656–663
Virus‐delivered small RNA silencing sustains strength in amyotrophic lateral sclerosis
Authors: Miller Timothy M. , Kaspar Brian K. , Kops Geert J. , Yamanaka Koji , Christian Lindsey J. , Gage Fred H. , Cleveland Don W.
Published: April 2005

Mutations in superoxide dismutase cause a subset of familial amyotrophic lateral sclerosis and provoke progressive paralysis when expressed in mice. After retrograde transport to the spinal cord following injection into muscles, an adeno‐associated virus carrying a gene that encodes a small interfering RNA was shown to target superoxide dismutase messenger RNA for degradation. The corresponding decrease in mutant superoxide dismutase in spinal motor neurons preserved grip strength. This finding provides proof of principle for the selective reduction of any neuronal protein and supports intramuscular injections of a small interfering RNA–encoding virus as a viable therapy for this type of familial amyotrophic lateral sclerosis. Ann Neurol 2005;57:773–776
Severe neuropathy with leaky connexin32 hemichannels
Authors: Liang Grace S. Lin , de Miguel Marta , Gómez‐Hernández Juan M. , Glass Jonathan D. , Scherer Steven S. , Mintz Mark , Barrio Luis C. , Fischbeck Kenneth H.
Published: April 2005

X‐linked Charcot‐Marie‐Tooth disease is one of a set of diseases caused by mutations in gap junction proteins called connexins. We identified a connexin32 missense mutation (F235C) in a girl with unusually severe neuropathy. The localization and trafficking of the mutant protein in cell culture was normal, but electrophysiological studies showed that the mutation caused abnormal hemichannel opening, with excessive permeability of the plasma membrane and decreased cell survival. Abnormal leakiness of connexin hemichannels is likely a mechanism of cellular toxicity in this and perhaps other diseases caused by connexin mutations. Ann Neurol 2005;57:749–754
Neuroprotection by the PGE2 EP2 receptor in permanent focal cerebral ischemia
Authors: Liu Dong , Wu Liejun , Breyer Richard , Mattson Mark P. , Andreasson Katrin
Published: April 2005

Recent studies suggest a neuroprotective function of the PGE2 EP2 receptor in excitotoxic neuronal injury. The function of the EP2 receptor was examined at time points after excitotoxicity in an organotypic hippocampal model of N‐methyl‐D‐aspartate (NMDA) challenge and in a permanent model of focal forebrain ischemia. Activation of EP2 led to significant neuroprotection in hippocampal slices up to 3 hours after a toxic NMDA stimulus. Genetic deletion of EP2 resulted in a marked increase in stroke volume in the permanent middle cerebral artery occlusion model. These findings support further investigation into therapeutic strategies targeting the EP2 receptor in stroke. Ann Neurol 2005;57:758–761
Interferon‐α/β–mediated innate immune mechanisms in dermatomyositis
Authors: Greenberg Steven A. , Pinkus Jack L. , Pinkus Geraldine S. , Burleson Travis , Sanoudou Despina , Tawil Rabi , Barohn Richard J. , Saperstein David S. , Briemberg Hannah R. , Ericsson Maria , Park Peter , Amato Anthony A.
Published: April 2005

Dermatomyositis has been modeled as an autoimmune disease largely mediated by the adaptive immune system, including a local humorally mediated response with B and T helper cell muscle infiltration, antibody and complement‐mediated injury of capillaries, and perifascicular atrophy of muscle fibers caused by ischemia. To further understand the pathophysiology of dermatomyositis, we used microarrays, computational methods, immunohistochemistry and electron microscopy to study muscle specimens from 67 patients, 54 with inflammatory myopathies, 14 with dermatomyositis. In dermatomyositis, genes induced by interferon‐α/β were highly overexpressed, and immunohistochemistry for the interferon‐α/β inducible protein MxA showed dense staining of perifascicular, and, sometimes all myofibers in 8/14 patients and on capillaries in 13/14 patients. Of 36 patients with other inflammatory myopathies, 1 patient had faint MxA staining of myofibers and 3 of capillaries. Plasmacytoid dendritic cells, potent CD4+ cellular sources of interferon‐α, are present in substantial numbers in dermatomyositis and may account for most of the cells previously identified as T helper cells. In addition to an adaptive immune response, an innate immune response characterized by plasmacytoid dendritic cell infiltration and interferon‐α/β inducible gene and protein expression may be an important part of the pathogenesis of dermatomyositis, as it appears to be in systemic lupus erythematosus. Ann Neurol 2005;57:664–678
Transient ischemic attack with infarction: A unique syndrome?
Authors: Ay Hakan , Koroshetz Walter J. , Benner Thomas , Vangel Mark G. , Wu Ona , Schwamm Lee H. , Sorensen A. Gregory
Published: April 2005

It is debated whether transient symptoms associated with infarction (TSI) are best considered a minor ischemic stroke, a subtype of transient ischemic attack (TIA), or a separate ischemic brain syndrome. We studied clinical and imaging features to establish similarities and differences among ischemic stroke, TIA without infarction, and TSI. Eighty‐seven consecutive patients with TIA and 74 patients with ischemic stroke were studied. All underwent diffusion‐weighted imaging on admission. Symptom duration and infarct volume were determined in each group. Thirty‐six patients (41.3%) with TIA had acute infarct(s). Although TIA‐related infarcts were smaller than those associated with ischemic stroke (mean, 0.7 vs 27.3ml; p < 0.001), there was no lesion size threshold that distinguished ischemic stroke from TSI. In contrast, the symptom duration probability density curve was not broad, but instead peaked early with only a few patients having symptoms for longer than 200 minutes. The probability density function for symptom duration was similar between TIA with or without infarction. The in‐hospital recurrent ischemic stroke and TIA rate was 19.4% in patients with TSI and 1.3% in those with ischemic stroke. TIA with infarction appears to have unique features separate from TIA without infarction and ischemic stroke. We propose identifying TSI as a separate clinical syndrome with distinct prognostic features. Ann Neurol 2005;57:679–686
Highly active antiretroviral therapy and human immunodeficiency virus encephalitis
Authors: Cook Jennifer E. , Dasgupta Somsankar , Middaugh Lawrence D. , Terry Elaine C. , Gorry Paul R. , Wesselingh Steven L. , Tyor William R.
Published: April 2005

The ability of highly active antiretroviral therapy (HAART) to prevent the onset of HIV‐associated dementia and to prevent or reduce the neuropathological features of HIV encephalitis (HIVE) remains unclear. Using a severe combined immunodeficient (SCID) mouse model of HIVE, we determined the effects of regular HAART treatment on HIVE. Before studying HAART in infected SCID mice, nonmanipulated SCID mice were treated with a single injection of the HAART cocktail (consisting of zidovudine, lamivudine, and indinavir) to determine optimum dosage and sampling time and to measure antiretroviral levels in the brain. After these preliminary studies, SCID mice that were inoculated with either HIV‐infected or uninfected human monocytes were given intraperitoneal (IP) injections of HAART three times daily over a 1‐ and 2‐week period. All three drugs were detected in the brain using a novel drug extraction technique and a modified high‐performance liquid chromatography method. HAART significantly decreased the amount of astrogliosis and viral load in treated mice compared with mice that received vehicle injections. These studies offer insight into the ability of HAART to treat HIV infection of the brain. Ann Neurol 2005