bluuebunny/crossref_metadata_2025 huggingface dataset:
Factors predicting language lateralization in patients with perisylvian vascular malformations
Authors: Lee Darrin J. , Pouratian Nader , Bookheimer Susan Y. , Martin Neil A.
Published: March 2010

Object

The authors conducted a study to determine the factors associated with right-sided language dominance in patients with cerebrovascular malformations.

Methods

Twenty-two patients with either arteriovenous malformations (AVMs [15 cases]) or cavernous malformations (7 cases) underwent functional MR (fMR) imaging studies of language function; a 3.0-T head-only unit was used. Lateralization indices were calculated separately for Broca and Wernicke areas. Lesion size, Spetzler-Martin grade, and the distance between the lesion and anatomically defined language cortex were calculated for each patient.

Results

Right-sided language dominance occurred in 5 patients, all of whom had AVMs within 10 mm of canonical language areas. Three patients had right-sided language dominance in the Wernicke area alone whereas 2 had right-sided language dominance in both Broca and Wernicke areas. Wada testing and intraoperative electrocortical stimulation were performed as clinically indicated to corroborate fMR imaging findings.

Conclusions

The primary factor associated with right-sided language dominance was the AVM being within 10 mm of anatomically defined language areas. The lesion size and the Spetzler-Martin grade were not significant factors. Anomalous fMR imaging laterality was typically confined to the language area proximate to the lesion, with the distal language area remaining in the left hemisphere dominant. This study emphasizes the need to map each case individually in patients with left perisylvian AVMs. Assumptions about eloquent cortex based on anatomical landmarks (a key component of Spetzler-Martin grading) may have to be reconsidered.
New Cytotoxic Azaphilones from Monascus purpureus-Fermented Rice (Red Yeast Rice)
Authors: Li Jin-Jie , Shang Xiao-Ya , Li Ling-Ling , Liu Ming-Tao , Zheng Jian-Quan , Jin Zong-Lian
Published: March 2010

Using a cell-based cytotoxicity assay three new cytotoxic azaphilones, including two stereoisomers and designated monapurones A-C (1-3), were isolated from the extract of Monascus purpureus-fermented rice (red yeast rice). Their structures were elucidated by detailed interpretation of spectroscopic and chemical data. The relative configurations were assigned on the basis of analysis of NOE data, and the absolute configurations were determined by direct comparison of their CD spectra with those of known azaphilones and chemical correlations. In the in vitro assays, monapurones A-C (1-3) showed selective cytotoxicity against human cancer cell line A549 with IC50 values of 3.8, 2.8 and 2.4mM respectively, while exhibiting no significant toxicity to normal MRC-5 and WI-38 cells at the same concentration.
Environmental Factors and Interactions with Mycobiota of Grain and Grapes: Effects on Growth, Deoxynivalenol and Ochratoxin Production by Fusarium culmorum and Aspergillus carbonarius
Authors: Magan Naresh , Aldred David , Hope Russell , Mitchell David
Published: March 2010

Mycotoxigenic fungi colonizing food matrices are inevitably competing with a wide range of other resident fungi. The outcomes of these interactions are influenced by the prevailing environmental conditions and the competing species. We have evaluated the competitiveness of F. culmorum and A. carbonarius in the grain and grape food chain for their in vitro and in situ dominance in the presence of other fungi, and the effect that such interactions have on colony interactions, growth and deoxynivalenol (DON) and ochratoxin A (OTA) production. The Index of Dominance shows that changes in water activity (aw) and temperature affect the competitiveness of F. culmorum and A. carbonarius against up to nine different fungi. Growth of both mycotoxigenic species was sometimes inhibited by the presence of other competing fungi. For example, A. niger uniseriate and biseriate species decreased growth of A. carbonarius, while Aureobasidium pullulans and Cladosporium species stimulated growth. Similar changes were observed when F. graminearum was interacting with other grain fungi such as Alternaria alternata, Cladopsorium herbarum and Epicoccum nigrum. The impact on DON and OTA production was very different. For F. culmorum, the presence of other species often inhibited DON production over a range of environmental conditions. For A.carbonarius, on a grape–based medium, the presence of certain species resulted in a significant stimulation of OTA production. However, this was influenced by both temperature and aw level. This suggests that the final mycotoxin concentrations observed in food matrices may be due to complex interactions between species and the environmental history of the samples analyzed.
A short and efficient synthesis of valsartan via a Negishi reaction
Authors: Ghosh Samir , Kumar A Sanjeev , Mehta G N
Published: March 2010

An efficient synthesis of the angiotensin-II inhibitor valsartan (Diovan®) is presented. Directed ortho-metalation of 5-phenyl-1-trityl-1H-tetrazole (6) and its Negishi coupling with aryl bromide 5 are the key steps of the synthesis. This method overcomes many of the drawbacks associated with previously reported syntheses.
Evaluating Institutional Green Building Policies: A Mixed-Methods Approach
Authors: Cupido Anthony F , Baetz Brian W , Pujari Ashish , Chidiac Samir
Published: March 2010

Sustainable or green building practices have been adopted recently by many higher education institutions for their new campus buildings and major renovations. To date, no formal study has been conducted to determine if policy is essential for sustainable building practices and the implementation of LEED®for these institutional green buildings in North America. A mixed-methods approach consisting of a quantitative survey and qualitative interviews was undertaken with senior facility professionals at higher education institutions in North America. The survey evaluated the institution's use of a policy, guideline, standard, law or goal related to sustainable building practices and the interview identified specific practices as well as issues such as leadership, policy compliance and barriers to adopting sustainable building policies. This paper provides a framework for an institutional sustainable building policy that is suitable to use as a template for senior facility professionals and their specific policy development. This work contributes to a foundation for future research related to sustainable/green building policy development and its application to the higher education sector.
An Agent Simulation Study on Conflict, Community Climate and Innovation in Open Source Communities
Authors: Yilmaz Levent
Published: March 2010

More than ever the complexity of innovation requires group efforts, as teams of scientists and engineers from diverse backgrounds work together to solve problems. One of the significant problems in understanding emergence of innovation involves how virtual innovation organizations and communities govern and coordinate to maximize innovation output. An agent simulation study is conducted to examine the impact of culture and conflict management styles on collective creativity in open source innovation systems. Findings suggest that decentralized coordination schemes such as emergent selection such as found in utility communities and moderate degrees of assertiveness and cooperation for conflict management result in higher incidence of innovation.
Ontogeny of Stromal Organizer Cells during Lymph Node Development
Authors: Bénézech Cécile , White Andrea , Mader Emma , Serre Karine , Parnell Sonia , Pfeffer Klaus , Ware Carl F. , Anderson Graham , Caamaño Jorge H.
Published: March 2010

The development of secondary lymphoid organs, such as lymph nodes (LNs), in the embryo results from the reciprocal action between lymphoid tissue inducer (LTi) cells and stromal cells. However, the initial events inducing LN anlagen formation before the LTi stromal cells cross-talk interactions take place are not fully elucidated. In this study, we show that the inguinal LN anlagen in mouse embryos developed from mesenchymal cells surrounding the lymph sacs, spherical structures of endothelial cells that bud from veins. Using inguinal and mesenteric LNs (mLNs), we provide evidence supporting a two-step maturation model for stromal cells: first, ICAM-1−VCAM-1− mesenchymal precursor cells become ICAM-1intVCAM-1int cells, in a process independent of LTi cells and lymphotoxin β receptor (LTβR) signaling. The second step involves the maturation of ICAM-1intVCAM-1int cells to ICAM-1highVCAM-1high mucosal addressin cell adhesion molecule-1+ organizer cells and depends on both LTi cells and LTβR. Addition of αLTβR agonist to LN organ cultures was sufficient to induce ICAM-1intVCAM-1int cells to mature. In LtβR−/− embryos, both inguinal and mLN stromal cells showed a block at the ICAM-1intVCAM-1int stage, and, contrary to inguinal LNs, mLNs persist longer and contained LTi cells, which correlated with the sustained gene expression of Il-7, Cxcl13, and, to a lesser degree, Ccl21. Taken together, these results highlight the importance of the signals and cellular interactions that induce the maturation of stromal cells and ultimately lead to the formation of lymphoid tissues.
A Thirteen Year Old Female with Primary T-Cell Rich B-Cell Lymphoma of Bone Masquerading as Chronic Recurrent Multifocal Osteomyelitis
Authors: Haque Saadiya , Shad Aziza , Ozdemirli Metin , Shanmugam Victoria , Kallakury Bhaskar
Published: March 2010

Primary lymphoma of the bone (PLB) accounts for 2% of all non-Hodgkin’s lymphomas, and until recently it had not been well characterized in literature. Most cases present in adulthood (average age 50), with localized painful lesions in the long bones, cranium, or axial skeleton. We describe a case of multifocal PLB in an adolescent female. In this case, the initial presentation, with migratory large joint polyarthralgias and bone pain, mimicked chronic recurrent multifocal osteomyelitis (CRMO). Had a biopsy not been performed the diagnosis would have been missed.
Pediatric Thioridazine Poisoning as a Result of Pharmacy Compounding Error
Authors: Kato Zenichiro , Nakamura Mitsuhiro , Yamagishi Yuka , Teramoto Takahide , Kondo Naomi
Published: March 2010

The adverse effects or overdose of thioridazine including sudden death, fatal arrhythmia, or retinopathy, in addition to the neurological signs have been reported. A three-year-old boy with bronchitis was prescribed erythromycin by a local clinic, but he started to complain of severe drowsiness and became unconscious. It was decided that this was a result of a compounding error of thioridazine instead of erythromycin owing to their similar commercial names. The thioridazine concentration in the child’s serum on admission was two to three times higher than the Cmax for adults with the same dosage. The concentration of the lavage saline on admission was only 0.3% of the ingested amount, indicating that the lavage was not effective in our case. Pharmacokinetic analysis revealed the parameters as Tmax, 1.5 hr; Cmax, 1700 ng/mL; Ka, 2.01 L/hr; Vd, 3.6 L/kg; and T1/2, 6.8 hr. Further investigations on clinical cases with a pharmacokinetic analysis should be done to confirm the pharmacokinetic evidence obtained here and to give specific therapeutic guidelines for overdose management especially in children.
Inclusion of Non-Viable Neonates in the Birth Record and Its Impact on Infant Mortality Rates in Shelby County, Tennessee, USA
Authors: Williams Bryan L. , Magsumbol Melina S.
Published: March 2010

Rates of infant death are one of the most common indicators of a population’s overall health status. Infant mortality rates (IMRs) are used to make broad inferences about the quality of health care, effects of health policies and even environmental quality. The purpose of our study was threefold: i) to examine the characteristics of births in the area in relation to gestational age and birthweight; ii) to estimate infant mortality using variable gestational age and/or birthweight criteria for live birth, and iii) to calculate proportional mortality ratios for each cause of death using variable gestational age and/or birthweight criteria for live birth. We conducted a retrospective analysis of all Shelby County resident-linked birth and infant death certificates during the years 1999 to 2004. Descriptive test statistics were used to examine infant mortality rates in relation to specific maternal and infant risk factors. Through careful examination of 1999-2004 resident-linked birth and infant death data sets, we observed a disproportionate number of non-viable live births (≤20 weeks gestation or ≤350 grams) in Shelby County. Issuance of birth certificates to these non-viable neonates is a factor that contributes to an inflated IMR. Our study demonstrates the complexity and the appropriateness of comparing infant mortality rates in smaller geographic units, given the unique characteristics of live births in Shelby County. The disproportionate number of pre-viable infants born in Shelby County greatly obfuscates neonatal mortality and de-emphasizes the importance of post-neonatal mortality.
Intraosseous Fluid Resuscitation in Meningococcal Disease and Lower Limb Injury
Authors: Dasgupta Suparna , Playfor Stephen D.
Published: March 2010

We set out to review the recent incidence of extravasation and compartment syndrome in children with meningococcal disease admitted to our Paediatric Intensive Care Unit (PICU) who had been resuscitated with intraosseous (IO) needles. Over a 12-month period, 18 children were admitted to PICU with meningococcal sepsis. Four of these children were resuscitated with IO needles and 2 developed serious complications as a result of extravasation and compartment syndrome. Clinical practice guidelines for children with severe sepsis advocate aggressive early fluid resuscitation therapy. We have identified extravasation and lower limb injury as a potential issue of increasing concern with appropriate aggressive IO fluid resuscitation in severe septic shock in children. Powered IO access systems such as the EZ-IO system offer advantages in terms of placement speed, accuracy and bone entry site profile at minimal extra financial cost.
Mutagenic Activity Assessment of Cristais River, São Paulo, Brazil, Using the Blue Rayon/Salmonella Microsome and the Tradescantia pallida Micronuclei Assays
Authors: Umbuzeiro Gisela de Aragão , Coimbrão C. A. , Kummrow Fábio , Lobo D. J. A. , Saldiva P. H. N.
Published: March 2010

Cristais River, located in the metropolitan region of São Paulo city, is used as source of drinking water and mutagenic activity was observed in the extracts obtained from its waters. This effect was associated to a discharge of a textile dye processing plant that contains, among other mutagenic compounds, the dyes C.I. Disperse Blue 373, C.I. Disperse Violet 93 and C.I. Disperse Orange 37. The objective of this work was to assess the mutagenic activity using the blue rayon hanging technique (BR)/Salmonella microsome assay and the Tradescantia-MCN mutagenicity test exposed in the fieldfor 24 hours before and after the discharge of the cited industrial effluent. The BR/Salmonella microsome assay showed to be sensitive to detect the mutagenicity, after the textile dye processing plant discharge. The Trad-MCN assay, using plant cuttings exposed directly in the river showed an increased response after the industrial discharge. Due to its simplicity and low cost, the Trad-MCN assay seems to be a good alternative for screening surface waters for mutagenic activity. Both techniques have the advantage of better represent the environmental conditions because the extraction/exposure is performed in the field during 24 hours.
Occurrence of Endocrine Disrupting Chemicals and Pharmaceutical Products in Surface Freshwaters From Campinas Region (SP, Brazil)
Authors: Sodré Fernando F. , Montagner C. C. , Locatelli M. A. F. , Jardim W. F.
Published: March 2010

The aim of this work was to evaluate the occurrence of some emerging organic compounds in surface freshwater samples collected in the Metropolitan Region of Campinas. Ten substances classified as endocrine disrupting chemicals as well as five pharmaceutical drugs were investigated in samples from six individual sampling points in the Atibaia River basin. Samples were submitted to solid phase extraction and the extracts were analyzed by high performance liquid chromatography. Exogenous organic compounds were detected in 83% of the samples. More than one compound, amongst the fifteen, was determined in 66% of the samples. 17β-estradiol, 17α-ethynylestradiol, paracetamol (acetaminophen), acetylsalicylic acid, di-n-butyl phthalate, bisphenol A, and caffeine were detected at least once. Higher levels of 17β-estradiol, 17α-ethynylestradiol, bisphenol A, and caffeine were detected in the sampling point located downstream of the city of Campinas, evidencing the contamination in this water body. Finally, it was noticed that during the low precipitation period the concentration of the majority of analyzed compounds increases.
The individual tolerance concept is not the sole explanation for the probit dose-effect model
Authors: Newman Michael C , McCloskey John T
Published: March 2010

Predominant methods for analyzing dose- or concentration-effect data (i.e., probit analysis) are based on the concept of individual tolerance or individual effective dose (IED, the smallest characteristic dose needed to kill an individual). An alternative explanation (stochasticity hypothesis) is that individuals do not have unique tolerances: death results from stochastic processes occurring similarly in all individuals. These opposing hypotheses were tested with two types of experiments. First, time to stupefaction (TTS) was measured for zebra fish (Brachydanio rerio) exposed to benzocaine. The same 40 fish were exposed during five trials to test if the same order for TTS was maintained among trials. The IED hypothesis was supported with a minor stochastic component being present. Second, eastern mosquitofish (Gambusia holbrooki) were exposed to sublethal or lethal NaCl concentrations until a large portion of the lethally exposed fish died. After sufficient time for recovery, fish sublethally exposed and fish surviving lethal exposure were exposed simultaneously to lethal NaCl concentrations. No statistically significant effect was found of previous exposure on survival time but a large stochastic component to the survival dynamics was obvious. Repetition of this second type of test with pentachlorophenol also provided no support for the IED hypothesis. We conclude that neither hypothesis alone was the sole or dominant explanation for the lognormal (probit) model. Determination of the correct explanation (IED or stochastic) or the relative contributions of each is crucial to predicting consequences to populations after repeated or chronic exposures to any particular toxicant.
Arctic char (Salvelinus alpinus) metallothionein: cDNA sequence, expression, and tissue-specific inhibition of cadmium-mediated metallothionein induction by 17β-estradiol, 4-OH-PCB 30, and PCB 104
Authors: Gerpe Marcela , Kling Peter , Berg Axel Håkan , Olsson Per-Erik
Published: March 2010

In this study, we haveexamined the basallevel expression and tissue-specificexpressionpatternsof metallothionein (MT) in Arctic char following metal and E2 (17β-estradiol) treatment. To study the gene regulation in Arctic char, the two MT isoforms were isolated from a lambda-ZAP hepatic cDNA library and characterized. Determination of basal MT mRNA and MT expression for 10 different tissues revealed a lack of correlation between MT mRNA and MT levels. The inducibility of MT mRNA and the correlation to resulting MT levels were then determined for liver and kidney. We found a more rapid and stronger induction of MT mRNA in liver than in kidney at day 1 and 3 postinjection, whereas the MT protein quantification showed higher MT levels in kidney than in liver at days 3 and 7 postinjection. These discrepancies indicate that differences in metal handling or posttran-scriptional regulation of MT exists between tissues. Whereas metals induce MT synthesis, E2 inhibit the hepatic MT expression. To examine the tissue specificity of this inhibition, we determined the effect of 17pj-estradiol (E2) and two estrogenic PCBs (4′-OH-PCB 30 and PCB 104) on Cd-mediated MT induction in liver and kidney. Although E2 and the estrogenic PCBs inhibited cadmium-mediated hepatic MT induction, these compounds did not interfere with renal MT induction.
Experimental determination of bioconcentration of the nonionic surfactant alcohol ethoxylate
Authors: Tolls Johannes , Haller Manuela , Labee Erik , Verweij Miriam , Sijm Dick T. H M
Published: March 2010

Acohol ethoxylate (AE) is the most widely usednonionic surfactant in householddetergents. Herewe present compound-specific bioconcentration data for AE constituents determined in flow-through experiments. Values of the bioconcentration factor (BCF) and the rate constants of uptake (k1) and elimination (k2) in fathead minnows (Pimephales promelas) ranged between <5 and 390 L/kg, 330 and 1,660 L/kg/d, and 3.3 and 59/d, respectively. The high values of k2 suggested rapid biotransformation of AE. As a consequence, AE was not stored inside the fish, and no relationship between the BCF and the lipid content was observed. The influence of both the alkyl and the ethoxylate chain length was studied. The BCF as well as k1 increased with increasing length of the alkyl chain and decreasing length of the ethoxylate chain. In contrast, a decrease of k2 with increasing alkyl chain length and decreasing ethoxylate chain length was found. Using structure–bioconcentration relationships, the bioconcentration potential of an AE mixture was estimated to be 140 L/kg. The bioconcentration potential of AE seemed to be largely unaffected by processes occurring during wastewater treatment.
Use of a bench-top photochemical reactor and solid-phase microextraction to measure semivolatile organic compound-hydroxyl radical rate constants
Authors: Bernhard Mary Jo , Simonich Staci L
Published: March 2010

It is increasingly important to be able to measure semivolatile organic compound-hydroxyl (SOC-OH) radical rate constants and estimate semivolatile organic compounds' (SOCs) atmospheric half-lives because of potential for atmospheric long-range transport. We have used a bench-top photochemical reactor, along with solid-phase microextraction (SPME) and ethyl nitrite, to successfully measure the rate constants of naphthalene, linalool, biphenyl, and phenanthrene with hydroxyl (OH) radical. Biphenyl and phenanthrene underwent wall loss in the reactor. The wall loss rates were determined and were used to correct the measured gas-phase rate constants. The reaction rate constants for naphthalene, linalool, biphenyl, and phenanthrene with OH radical, in our bench-top system at 295 ± 3 K, were determined to be 2.73 ± 0.37 × 10−11, 1.93 ± 0.24 × 10−10, 7.44 ± 1.9 × 10−12, 1.73 ± 0.21 × 10−11 (cm3/molecule/s), respectively, and were in excellent agreement with previous studies and model predictions. Based on the range of experimental and predicted rate constants for these reactants and an estimated average OH concentration in the atmosphere, the atmospheric half-lives of these SOCs are significantly less than 2 d. This indicates that the global presence of these compounds in the atmosphere is primarily due to regional sources and not to atmospheric long-range transport. This study shows that bench-top reactors, combined with corrections for reactant wall loss and simplified analytical tools (such as solid-phase microextraction), can be used to measure SOC-OH rate constants.
Measuring atmospheric pollution around junction 16 of the M25 Motorway, London, United Kingdom, using lichenophagous invertebrates
Authors: Sims Ian , Lacey Robert
Published: March 2010

We investigate some environmental effects of exhaust emissions from motorway traffic in an area centered on the Junction 16 interchange of the M25 (London Orbital Motorway, UK) with the M40 (London-to-Birmingham Motorway, UK). This junction is surrounded by woodland and farmland, with urban development to the west and east. Both motorways carry large volumes of vehicular traffic, so one would expect exhaust-related air pollution to be higher downwind of the junction than in the surrounding area. Epiphytic algae were collected, analyzed, and used as a pabulum for lichenophagous insect larvae. Analysis showed the concentrations of exhaust-related heavy metals in algal samples collected downwind were generally higher than those for the surrounding areas. An experiment in which insect larvae were fed these algae identified 13 sites that were significantly affected in two discrete areas: the area with high metals to the east (downwind) of Junction 16, and an area of intensively managed forestry with low metals on the western edge of the survey area. These results suggest this methodology may be a useful screening tool for monitoring air quality and managing the biological effects of atmospheric contaminants. Data from such studies would increase the trophic representation of risk assessments for atmospheric contaminants.
Influence of sexual dimorphism in Chironomus riparius Meigen on toxic effects of cadmium
Authors: Sildanchandra Wanwisu , Crane Mark
Published: March 2010

Second instars of Chironomus riparius Meigen were exposed to different concentrations of Cd-spiked sediment to determine effects on males and females. The wet weights of the larvae were determined after 10 d of exposure. The animals were then returned to the sediment and allowed to emerge. Time to emergence, sex, and adult survival time were recorded. Larval weights declined with increasing Cd concentrations, but the concentration–weight responses of males and females were similar. Hence, the impact of sexual dimorphism on growth measurements in sediment toxicity tests is likely to be small. The cumulative emergence of male and female chironomids did not differ significantly between sexes, except at Cd at 3,200 mg/L (measured sediment concentration 317 μg/kg). Adults emerged from controls between days 9 and 10 and from treatments up to and including Cd at 3,200 mg/L treatment within 18 d. Only one adult emerged from the treatment with Cd at 12,800 mg/L (measured sediment concentration 446 μg/kg), and time to emergence was delayed until day 30. This study has confirmed that Cd in sediments can reduce the survival, growth, development, and emergence of C. riparius, and that emergence patterns may differ between the sexes at higher concentrations of Cd. However, the difference between sexes in effects on larval growth will not greatly influence the results of toxicity tests if test treatments contain different proportions of males and females. Whether survivorship of the sexes differs when larval stages are exposed to Cd remains unclear.
Zinc toxicity thresholds for important reclamation grass species of the western united states
Authors: Paschke Mark W , Redente Edward F , Levy David B
Published: March 2010

Heavy metal toxicity thresholds for plant species that are used in reclamation activities in Western North America have not been established. As a result, ecological risk assessments must rely on toxicity thresholds established for agronomic species, which may differ from those of species used in reclamation. As a result, risk assessors have the potential for classifying sites as phytotoxic to perennial, nonagronomic species and calling for intensive remediation activities that may not be necessary. The objective of this study was to provide a better estimate of Zn toxicity thresholds for five grass species that are commonly used in reclamation efforts in the western United States. We used a greenhouse screening study where seedlings of redtop (Agrostis albas Roth), slender wheatgrass (Elymus trachycaulus [Link] Gould ex Shinners var. Pryor), tufted hairgrass (Deschampsia caespitosa (L.) Beauv.), big bluegrass (Poa ampla J. Presl var. Sherman), and Great Basin wildrye (Leymus cinereus [Scribn.&Merr.] A. Löve var. Magnar) were grown in sand culture and exposed to concentrations of soluble Zn ranging from 0.6 (control) to 500 mg/L. We determined six measures of toxicity: the 50-d LC50, 50-d EC50-plant, 50-d EC50-shoot, 50-d EC50-root, PT50-shoot, and PT50-root. Results suggest that these grass species have higher Zn phytotoxicity thresholds (PT50s) than agronomic species reported in the past. Roots appeared to be more susceptible to the toxic effects of zinc (as indicated by reduced growth) than shoots. This observation suggests that measures of EC50-shoot alone may be misleading for these species where growth reduction is manifested primarily in roots. Values of EC50-plant for these reclamation grasses were between 84 and 222 mg/L. Measured PT50-shoot values were between 2,449 and 5,026 mg/L. These thresholds should be more useful for risk assessors than those based on agronomic crops that are currently used.
Quantitative structure–activity relationships: Comparative inhibition of nitrogen-containing aromatics on germination of Cucumis sativus
Authors: Wang Xiaodong , Sun Cheng , Wang Liansheng , Han Shuokui
Published: March 2010

Comparative inhibition effect of selected nitrogen-containing aromatics on germination rate of Cucumis sativus was investigated, and quantitative structure–activity relationships were developed and mechanistically interpreted. Energy of lowest unoccupied orbital was found to successfully model the toxicity of the test chemicals. It was discovered that inhibition of nitrogen-containing aromatics to germination of Cucumis sativus was caused mainly by their in vivo redox reaction.
Variations in heavy metal concentrations and speciation in two mining-polluted streams in central Norway
Authors: Gundersen Pål , Olsvik Pål A. , Steinnes E.
Published: March 2010

The dissolved (dialysis in situ), colloidal (filtered minus dissolved), and total concentrations of Cu, Zn, Cd, and Al were determined and compared with pH, Ca concentrations, and alkalinities through seasonal variations in water levels in two streams, Rugla and Naustebekken, in the Røros area of central Norway. The main objective was to monitor the dissolved fraction of the metals during the seasons and to establish the extent to which chemical parameters influencing metal toxicity were unfavorable during episodes of high total metal concentrations. The average dissolved fractions of Cu, Zn, Cd, and Al were lower in Rugla (55, 69, 64, and 17%, respectively) compared with Naustebekken (59, 82, 82, and 30%, respectively). This is probably due to sedimentation of metal particles in a small lake located in the path of Naustebekken. Alkalinity and Ca concentrations were generally low during the flood episodes, when the highest metal concentrations occurred. This is unfavorable since these parameters are assumed to counteract toxic effects of metals. On the other hand, the results indicate that toxic stress during metal concentration peaks was moderated by adsorption of dissolved metal species on colloids and/or particles.
Localization of deposited polycyclic aromatic hydrocarbons in leaves of Plantago
Authors: Bakker Martine I , Koerselman Judith W , Tolls Johannes , Kollöffel Chris
Published: March 2010

After deposition to foliage, polycyclic aromatic hydrocarbons (PAHs) may remain on the leaf surface, accumulate in the cuticular wax, or diffuse into the remaining interior of the plant. In a field study, the location of deposited PAHs in the leaves of two Plantago species was determined. To this aim, leaves of Plantago major and Plantago media were divided into three fractions. First, the leaves were washed (wash-off fraction), then cuticular wax was extracted (wax fraction). Finally, the remaining leaf material was extracted (interior fraction). The presence of PAHs could be demonstrated in all three fractions. For both plants, the distribution of PAHs over the three fractions changed with molecular weight (mol wt) of the PAHs. The wash-off fraction increased with increasing molecular weight, likely because high molecular-weight PAHs occur predominantly bound to particles, which can be readily washed off from the leaves. In contrast, the amount of PAHs detected in the interior of the leaves decreased with increasing molecular weight. This can be explained by a slow desorption of the PAHs from the particles and a low diffusion rate of the larger molecules. This study shows that washing reduces the amount of high molecular-weight PAHs on plant surfaces. Therefore, washing of leafy vegetables is important to minimize human dietary intake of PAHs.
The use of acute and chronic bioassays to determine the ecological risk and bioremediation efficiency of oil-polluted soils
Authors: van Gestel Cornelis A M , van der Waarde Jaap J , Derksen J. G. M. (Anja) , van der Hoek Eline E , Veul Martin F X W , Bouwens Sandra , Rusch Ben , Kronenburg René , Stokman Gerard N M
Published: March 2010

To compare the effectiveness of acute and chronic bioassays for the ecological risk assessment of polluted soils, soil samples from a site with an historical mineral oil contamination (<50–3,300 mg oil/kg dry soil) at the Petroleum Harbour in Amsterdam, The Netherlands, were screened for ecological effects using acute and chronic bioassays. A two-step 0.001 M Ca(NO3)2 extraction at a final solution-to-soil ratio of 1:1 was used to prepare extracts for the acute bioassays. Acute bioassays (≤5 d) applied to the 0.001 M Ca(NO3)2 extracts from the polluted and reference soils included growth tests with bacteria (Bacillus sp.), algae (Raphidocelis subcapitata), and plants (Lactuca sativa), immobility tests with nematodes (Plectus acuminatus), springtails (Folsomia candida), and cladocerans (Daphnia magna), and the Microtox® test (Vibrio fischeri). Chronic bioassays (four weeks) performed on the same soil samples included tests with L. sativa, F. candida, and earthworms (Eisenia fetida) and the bait-lamina test (substrate consumption). The acute bioassays on Microtox showed a response that corresponded with the level of oil pollution. All other acute bioassays did not show such a consistent response, probably because pollutant levels were too low to cause acute effects. All chronic bioassays showed sublethal responses according to the contaminant levels (oil and in some soils also metals). This shows that chronic bioassays on soil samples are more sensitive in assessing the toxicity of mineral oil contamination in soil than acute bioassays on soil extracts. A pilot scale bioremediation study on soils taken from the two most polluted sites and a control site showed a rapid decline of oil concentrations to reach a stable level within eight weeks. Acute bioassays applied to the soils, using Microtox, algae, and D. magna, and chronic bioassays, using plants, Collembola, earthworms, and bait-lamina consumption, in all cases showed a rapid reduction of toxicity, which could be attributed to the degradation of light oil fractions.
Screening of environmental contaminants for ecdysteroid agonist and antagonist activity using the Drosophila melanogaster BII cell in vitro assay
Authors: Dinan Laurence , Bourne Pauline , Whiting Pensri , Dhadialla Tarlochan S , Hutchinson Thomas H
Published: March 2010

The BII bioassay was developed as a rapid and reliable tool for detecting potential insect growth regulators acting as ecdysteroid receptor (ant)agonists. Based on an ecdysteroid-responsive cell line from Drosophila melanogaster, this microplate assay is ideally suited to the evaluation of environmental contaminants as potential endocrine disrupters. Data are presented for about 80 potential environmental contaminants, including industrial chemicals, pesticides, Pharmaceuticals, phytoestrogens, and vertebrate steroids, and are compared with data for known (ant)agonists. Apart from androst-4-ene-3,17-dione (a weak antagonist), vertebrate steroids were inactive at concentrations up to 10−3 M. The vast majority of xenobiotics also showed no (ant)agonist activity. Among the industrial chemicals, antagonistic activity was observed for bisphenol A median effective concentration (EC50) of 1.0 × 10−4 M and diethylphthalate (EC50 of 2.0 × 10−3 M). Some organochlorine compounds also showed weak antagonistic activity, including o,p′-dichlorodiphenyldichloroethylene (DDE), p,p′-DDE, dieldrin, and lindane (EC50 of 3.0 × 10−5 M). For lindane, bisphenol A, and diethylphthalate, activity is not associated with impurities in the samples and, for lindane and bisphenol A at least, the compounds are able to compete with ecdysteroids for the ligand binding site on the receptor complex, albeit at concentrations very much higher than those found in the environment. The only pharmaceutical showing any detectable antagonist activity was 17α-ethynylestradiol. In the context of recent publications on potential endocrine disruption in marine and freshwater arthropods, these findings suggest that, for some compounds (e.g., diethylstilbestrol), ecdysteroid receptor-mediated responses are unlikely to be involved in producing chronic effects. The BII assay has a potentially valuable role to play in distinguishing between endocrine-mediated, which normally occur at submicromolar concentrations, and pharmacological effects in insects and crustaceans.
Zinc and cadmium body burdens in terrestrial oligochaetes: Use and significance in environmental risk assessment
Authors: Lock Koen , Janssen Colin R
Published: March 2010

Uptake and elimination kinetics of zinc and cadmium were studied in the oligochaetes Enchytraeus albidus and Eisenia fetida. Even at the highest exposure concentrations where E. fetida survived, the internal zinc concentration was still regulated to a constant level. Enchytraeus albidus could not regulate the internal zinc concentration as well, and the body burden increased after exposure to high zinc concentrations. After transfer to clean soil, the internal zinc concentration dropped back to the control level within a few weeks. For both species, internal cadmium concentrations did not reach equilibrium during the uptake experiments. The internal concentrations causing 50% reduction in cocoon production for E. fetida exposed to cadmium varied between different soil types, indicating that no fixed critical body burdens exist. For both zinc and cadmium, bioaccumulation factors decreased with increasing soil metal concentrations. Bioaccumulation factors may therefore be poor indicators of environmental risk. Their dependence on the total soil concentration makes bioaccumulation factors also unsuitable for assessing the influence of soil characteristics on the bioavailability of metals in contaminated field soils. For the same reason, uptake rate constants are probably not suited for this purpose.
Sediment geochemical controls on Cd, Cr, and Zn assimilation by the clam Ruditapes philippinarum
Authors: Fan Wenhong , Wang Wen-Xiong
Published: March 2010

Several important sediment geochemical factors (particle size, contact time, artificial sediment composition, acid volatile sulfide, and pure inorganic particles coated or uncoated with humic acid) were examined for their influences on the assimilation of Cd, Cr, and Zn in the marine clam Ruditapes philippinarum. Metal desorption and phase speciation were concurrently measured for these particles. Differences in particle size did not significantly affect metal assimilation. Increasing contact time with sediments decreased assimilation by the clams of Cr and Zn, but not of Cd. A significant positive relationship was found between the metal assimilation efficiency (AE) and the metal partitioning in the exchangeable fraction of sediments for Cd and Zn. The assimilation of metals was negatively dependent on the metal distribution in the reducible (Fe oxide) fraction, indicating that Fe oxide reduced metal bioavailability to the clams. Metal AEs measured with artificially prepared sediments were comparable to those measured with natural sediments. The AEs were significantly higher in artificial sediment without Fe oxide. Humic acid coating appeared to have no major and consistent influence on metal assimilation by the clams. The AEs measured for pure inorganic particles were much higher than those measured for sediments or artificially prepared sediments, except for the Fe oxide particles, indicating that digestion may behave differently for pure particles. Metals bound to artificially synthesized acid volatile sulfide were much less bioavailable to the clams. The AEs were as low as 4% for Cd and 7% for Zn, whereas the AE for Cr was somewhat similar to those measured for other types of particles. When all particle types (natural sediments, artificial sediment, and pure particles) were considered, a significant relationship was found between Cd AE and its desorption in seawater. This study has demonstrated that several geochemical fractions of the sediments, particularly the exchangeable, Fe oxide, and sulfide fractions, are important in determining metal bioavailability from sediments to clams.
Optimizing interpretation of in situ effects of riverine pollutants: Impact of upwelling and downwelling
Authors: Greenberg Marc S. , Burton G. Allen , Rowland Carolyn D.
Published: March 2010

In situ toxicity and bioaccumulation tests with Ceriodaphnia dubia (48 h), Chironomus tentans (96 h), Hyalella azteca (96 h), and Lumbriculus variegatus (96 h) were conducted at three stations on a river that was contaminated primarily with chlorobenzenes (CBs), and results were compared to a nearby reference site. Exposures were characterized by using minipiezometers for contaminant profiling and determination of hydraulic heads and vertical flow direction within the sediments and measuring contaminants in sediment, surface water, and exposure chamber water samples. Localized zones of upwelling and downwelling existed in the exposure areas at contaminated sites 5 and 18, while site 23 was downwelling at all measurement positions. Porewater samples from minipiezometers contained CBs at the three contaminated sites that were highest at site 23. However, sediment and water samples from exposure chambers at site 23 contained the lowest levels of CBs among the contaminated sites. The CBs were not detected at the reference site, but other organic contaminants and metals were detected at all sites, with the highest concentrations occurring at sites 5 and 18. In water column exposures, no significant (p > 0.05) differences were observed in species survival between the contaminated sites and the reference. Mean percentage survival of H. azteca, C. dubia, and C. tentans exposed to surficial sediments (SS) at sites 5 and 18 was significantly (p < 0.05) reduced compared to the reference, whereas only C. tentans survival was significantly reduced at site 23. Body residues of total CB congeners in L. variegatus exposed to SS were highest at site 18 (618 μmol/kg lipid) and lowest at site 23 (21 μmol/kg lipid). The data suggest that downwelling reduced the bioavailability of CBs in surficial sediments, most likely by mobilizing the freely dissolved and colloid-bound fractions to deeper sediments. Overall, downwelling conditions reduced the in situ exposure of organisms in surficial sediments and hence the toxicity and bioaccumulation of CBs. Hydrologic and chemistry data from nested minipiezometers improved the interpretation of exposure-effects relationships.
Vitamins A1 and A2 in hepatic tissue and subcellular fractions in mink feeding on fish-based diets and exposed to Aroclor 1242
Authors: Käkelä Anne , Käkelä Reijo , Hyvärinen Heikki , Asikainen Juha
Published: March 2010

Two-month-old female mink were fed diets based on either Baltic herring (Clupea harengus membras) or freshwater smelt (Osmerus eperlanus) for 21 weeks. A portion of the smelt-fed mink were exposed orally to polychlorinated biphenyls (PCBs), Aroclor 1242 (1 mg/d). Retinol (vitamin A1), 3,4-didehydroretinol (vitamin A2), and their different fatty acyl esters were studied in hepatic tissue, microsomes, and cytosol by argentated reversed-phase high-performance liquid chromatography. As a result of Aroclor exposure, concentrations of the fatty acyl esters of vitamins A1 and A2 were about one-tenth and those of unesterified A2 one-fourth those of the control levels. In the fatty acyl esters, percentages of stearates (A1-18:0 and A2-18:0) increased at the expense of the other fatty acyl esters. The Aroclor exposure decreased concentrations of alcoholic and esterified forms of the A2 analog more than those of the corresponding A1 analog. In microsomes, Aroclor decreased the alcoholic and esterified vitamin analogs to the same extent (to 9–17%). In the cytosol compared to the control, the concentrations of the vitamin esters fell below 10%, but the alcoholic analogs remained at 30 to 40%. Despite equal dietary supply, in mink fed on Baltic herring, the hepatic levels of vitamin A1 were only about one-third of the values found in the smelt-fed mink. The organochlorines also altered hepatic lipid composition and impaired breeding and kit growth. In the kits of the females fed on Baltic herring, blood hemoglobin was decreased.
Benzo[a]pyrene absorption and exposure pathways in the green mussel Perna viridis
Authors: Wang Wen-Xiong , Chow Alex T. S.
Published: March 2010

The absorption efficiency (AE) of benzo[a]pyrene (BaP), a representative polycyclic aromatic hydrocarbon compound, in the green mussel Perna viridis was measured under different biological and food conditions (body size, food quantity, and food species). Uptake of BaP from the aqueous phase by different species of phytoplankton and green mussels was also experimentally quantified. A bioenergetic-based kinetic model was then used to separate the exposure pathways of BaP accumulation in the green mussels. Our results demonstrated that the AE of BaP in the green mussels ranged between 17 and 47%. Body size did not significantly affect the AE of BaP in the mussels. The AEs increased with a decrease in food availability, largely as a result of lengthening the gut passage of chemicals. The AEs differed by up to 2.3 times (17–39%) among the different food diets tested (four phytoplankton diets and one sediment diet). The BaP associated with the sediment was assimilated least efficiently. The difference in gut passage also appeared to account partially for the difference in AEs observed among different food types. No correlation between the AE and the distribution of BaP in the cytoplasm of phytoplankton cells was found. The concentration factor of BaP measured in four different marine phytoplankton species was in the range of 104 − 5 × 104 (L/kg). The calculated uptake rate constant of BaP in the green mussels was 6.37 L/g/d, and the efficiency of absorption of BaP from the aqueous phase was 6.6 to 8.8%. The model calculation indicated that under most circumstances, >56% of BaP in mussels can indeed be derived from the uptake from the aqueous phase. However, the relative importance of aqueous and dietary exposure can be affected by the variation of AE, mussel's ingestion rate, and concentration of BaP in ingested food particles.