bluuebunny/crossref_metadata_2025_split huggingface dataset:
Measurement of coronary flow response to cold pressor stress in asymptomatic women with cardiovascular risk factors using spiral velocity-encoded cine MRI at 3 tesla
Authors: Maroules Christopher D. , Chang Alice Y. , Kontak Andrew , Dimitrov Ivan , Kotys Melanie , Peshock Ronald M. 
Published: March 2010

Background: Coronary sinus (CS) flow in response to a provocative stress has been used as a surrogate measure of coronary flow reserve, and velocity-encoded cine (VEC) magnetic resonance imaging (MRI) is an established technique for measuring CS flow. In this study, the cold pressor test (CPT) was used to measure CS flow response because it elicits an endothelium-dependent coronary vasodilation that may afford greater sensitivity for detecting early changes in coronary endothelial function. Purpose: To investigate the feasibility and reproducibility of CS flow reactivity (CSFR) to CPT using spiral VEC MRI at 3 Tesla in a sample of asymptomatic women with cardiovascular risk factors. Material and Methods: Fourteen asymptomatic women (age 38 years ± 10) with cardiovascular risk factors were studied using 3D spiral VEC MRI of the CS at 3 T. The CPT was utilized as a provocative stress to measure changes in CS flow. CSFR to CPT was calculated from the ratio of CS flow during peak stress to baseline CS flow. Results: CPT induced a significant hemodynamic response as measured by a 45% increase in rate-pressure product ( P<0.01). A significant increase in CS volume flow was also observed (baseline, 116 ± 26 ml/min; peak stress, 152 ± 34 ml/min, P=0.01). CSFR to CPT was 1.31 ± 0.20. Test-retest variability of CS volume flow was 5% at baseline and 6% during peak stress. Conclusion: Spiral CS VEC MRI at 3 T is a feasible and reproducible technique for measuring CS flow in asymptomatic women at risk for cardiovascular disease. Significant changes in CSFR to CPT are detectable, without demanding pharmacologic stress.
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.
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

Abstract
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.
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

Abstract
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

Abstract
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

Abstract
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 &lt;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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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 (&lt;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.