bluuebunny/crossref_metadata_2025 huggingface dataset:
An evaluation of the etiology of reduced CYP1A1 messenger RNA expression in the Atlantic tomcod from the Hudson River, New York, USA, using reverse transcriptase polymerase chain reaction analysis
Authors: Roy Nirmal K , Courtenay Simon , Yuan Zhanpeng , Ikonomou Michael , Wirgin Isaac
Published: March 2010

Adult Atlantic tomcod, Microgadus tomcod, from the Hudson River, New York State, USA, exhibit reduced inducibility of hepatic cytochrome P4501A1 (CYP1A1) mRNA compared with adult tomcod from the cleaner Miramichi River, New Brunswick, Canada, when treated with coplanar polychlorinated biphenyl (PCB) congeners or 2,3,7,8-tetrachlorodibenzo-p-dioxin. In contrast, little difference in CYP1A1 inducibility is observed between tomcod from these two rivers when treated with polycyclic aromatic hydrocarbons (PAHs). We sought to determine if impaired hepatic CYP1A1 inducibility in Hudson River tomcod results from a multigenerational, genetic adaptation or a single generational, physiological acclimation. Embryos and larvae from controlled experimental crosses of Hudson River and Miramichi River parents were exposed for 24 h to water-borne PCB congener 77 (10 ppm), benzo[a]pyrene (BaP; 10 ppm), or dimethysulfoxide, and CYP1A1 expression was assessed in individual larva using competitive reverse transcriptase polymerase chain reaction (RT-PCR) analysis. The CYP1A1 mRNA was significantly induced in larvae from both populations by BaP (47- and 52-fold) and PCB 77 (9- and 22-fold), although levels of expression were higher in offspring of Miramichi matings. Most important, CYP1A1 mRNA was significantly induced by PCB 77 in larvae from Hudson River parents. Concentrations of dioxin, furan, and PCB congeners were measured in livers and eggs of female tomcod from these two locales to quantify the extent of maternal transfer of contaminants. For both rivers, wet-weight contaminant concentrations were significantly higher (4–7 times) in livers than in eggs of the same females, suggesting that a threshold level of contaminants may have to be reached before CYP1A1 transcription is impaired. We conclude that reduced inducibility of hepatic CYP1A1 mRNA in adult tomcod from the Hudson River is most consistent with single-generational acclimation.
Effects of salinity and chemical speciation on cadmium accumulation and toxicity to two mysid species
Authors: Roast Stephen D , Widdows John , Jones Malcolm B
Published: March 2010

The estuarine environment is characterized by frequent fluctuations in salinity. Consequently, organisms used for environmental monitoring of estuaries must be euryhaline so that their laboratory responses to chemical pollutants are measured under the full range of salinity exposures experienced in the field. Neomysis integer and Praunus flexuosus are two potential candidates for use in environmental monitoring of European estuaries. The present study assesses the effects of salinity on survival, trace metal accumulation, and toxicity to these two mysid species. Neomysis integer was more euryhaline, showing 100% survival at 1 to 40‰ compared with P. flexuosus, which showed 100% survival at salinities of 10 to 40‰. Toxicity of the free cadmium ion to both species was unaffected by salinity, and 96-h LC50s ranged from 4.8 to 15 μg Cd2+/L for N. integer and from 12.3 to 16 μg Cd2+/L for P. flexuosus. The 7-d LC50s ranged from 1.0 to 4.2 and 4.8 to 5.3 μg Cd2+/L for N. integer and P. flexuosus, respectively. No effect of exposure salinity was found on cadmium body burdens of mysids exposed for 7 d to 0.5 and 1.0 μg Cd2+/L. The results are discussed in terms of possible effects of osmoregulatory mechanisms on trace metal uptake, accumulation, and toxicity.
Determination and multivariate statistical analysis of biochemical responses to environmental contaminants in feral freshwater fishLeuciscus cephalusL.
Authors: Machala Miroslav , Dusek Ladislav , Hilscherova Klara , Kubinova Renata , Jurajda Pavel , Neca Jiri , Ulrich Robert , Gelnar Milan , Studnickova Zdena , Holoubek Ivan
Published: March 2010

Modulations of 11 prospective biochemical markers of impacts of aquatic pollutants in liver tissue of chub (Leuciscus cephalus), caught at several sampling sites of a river with various pollution types and rates, were matched against analytical data of concentrations of organochlorine compounds, polycyclic aromatic hydrocarbons (PAHs), and heavy metals. Multivariate principal component analysis (PCA) of the field data showed general patterns of biochemical responses to different types of pollutants and relationships among the biomarkers. Cytochrome P4501A-dependent 7-ethoxyresorufin O-deethylase (EROD) activity, inducible by 2,3,7,8-tetrachlorodibenzo-p-dioxin and structurally related planar compounds, was strongly enhanced in the more contaminated areas. Compared with polychlorinated aromatic hydrocarbons, PAHs did not contribute so significantly to EROD induction. Testosterone 6β- and 16α-hydroxylase activities, as an expression of the cytochrome P4503A27, were slightly increased at several sites but were significantly decreased in samples from some heavily polluted areas. Recently, these activities have been suggested as potential biomarkers of exposure to contaminants that do not induce cytochrome P4501A. In this study, their inhibition or induction was not associated with a specific class of monitored contaminants, and selectivities of these modulations are still to be investigated. Similar modulations of the prospective biochemical indicators of oxidative stress, including microsomal glutathione S-transferase activity, cytosolic glutathione S-transferase with ethacrynic acid, and glutathione reductase, were demonstrated by PCA. The pattern of the modulations of the microsomal nicotinamide adenine dinucleotide phosphate (NADPH)-dependent lipid peroxidation in vitro differed from the responses of the rest of oxidative stress parameters at some sampling sites. Further biochemical markers of oxidative stress under study, including in vivo lipid peroxidation, in vitro production of reactive oxygen species, and the concentration of metallothioneins did not correlate well with the concentrations of the contaminants. Principal component analysis demonstrated that the EROD activity, glutathione-dependent enzymes, and Fe(II)-enhanced lipid peroxidation formed a suitable battery of biomarkers of exposure.
Stable strontium accumulation by earthworms: A paradigm for radiostrontium interactions with its cationic analogue, calcium
Authors: Morgan John E , Richards Sarah P G , Morgan A John
Published: March 2010

The accumulation of stable strontium and its chemical analogue calcium by four species of earthworm, representing three distinct ecophysiological groups inhabiting celestite (SrSO4)-rich natural soils, was investigated. An increase in soil strontium concentration over a four-orders-of-magnitude range was accompanied by an increase in earthworm tissue strontium concentration. In contrast, no relationship between soil and tissue calcium concentrations was apparent, indicating that this essential cation is strongly regulated within earthworm tissues but that nonessential strontium burdens are not physiologically regulated. Concentration factors for strontium ranged from 0.1 to 1.42, with an inverse relationship between this parameter and soil strontium concentration. The use of concentration factors and discrimination coefficients lead to the conclusion that earthworms discriminate against strontium accumulation at increased soil calcium concentrations, such that strontium would be predicted to be more efficiently accumulated by worms inhabiting acidic, calcium-poor soils. Although few consistent trends in strontium and calcium concentration were apparent between earthworm species, the species with the highest calcium turnover (i.e., the litter-inhabiting Lumbricus rubellus) typically accumulated higher concentrations of strontium than representatives of contrasting ecophysiological classes. These findings are considered in the context of the distribution, retention, and cycling of radiostrontium in soils.
Fate and effects of esfenvalerate in agricultural ponds
Authors: Samsøe-Petersen Lise , Gustavson Kim , Madsen Torben , Mogensen Betty Bügel , Lassen Pia , Skjernov Kamilla , Christoffersen Kirsten , Jørgensen Erik
Published: March 2010

The fate of esfenvalerate was investigated by sampling and chemical analysis after spraying of an artificial pond (25 g a.i./ha) and in the laboratory with [14C]esfenvalerate by trapping of 14CO2 and fractionation of the sediment. The effects were investigated on pelagic communities in enclosures in a natural lake and in the laboratory on surface (Cymatia coleoptrata) and sediment (Chironomus riparius) insects. The latter were used in sediment-plus-water and in water-only tests, measuring effects on emergence and mortality. The measurements in the artificial pond indicated exposure concentrations in the surface microlayer, water column, and sediment of 0.4 μg/L, 0.05 μg/L, and 9 μg/kg dry weight, respectively, two weeks after application. The degradation studies showed a limited mineralization (26.5%) of [chlorophenyl-14C]esfenvalerate during 112 d. Part of the substance was transformed to water-soluble compounds (18.1%) or compounds attached to fulvic acids (26.2%), humic acids (14.2%), or nonextractable sediment constituents (8.8%). The formulated product Sumi-Alpha 5 FW® caused 100% mortality to Cymatia coleoptrata after surface application of 0.13 g a.i./ha. Effects on zooplankton were recorded at 0.005 μg/L of esfenvalerate. The 96-h median lethal concentration for first-instar larvae of Chironomus riparius was 0.13 μg/L, whereas the delayed emergence lowest-observed-effect concentration was 0.8 μg/L.
Utility of a juvenile fathead minnow screening assay for detecting (anti-)estrogenic substances
Authors: Panter Grace H. , Hutchinson Thomas H. , Länge Reinhard , Lye Christina M. , Sumpter John P. , Zerulla Melanie , Tyler Charles R.
Published: March 2010

The European Chemical Industry's aquatic research program for endocrine disrupters includes the development of an in vivo juvenile fathead minnow (Pimephales promelas) screening assay.Working within the Organization for Economic Cooperation and Development's (OECD, Paris, France) tiered approach to endocrine disrupter evaluation in fish, the juvenile fish screening protocol was adapted from the OECD test guideline 204. Six chemicals, with different (anti-)estrogenic potencies, were used to develop the in vivo juvenile fish screening protocol: diethylstilbestrol, 17α-ethynylestradiol, genistein, methoxychlor, 4-tert-pentylphenol, and ZM189,154 (a novel pharmaceutical antiestrogen). Mixed-sex juvenile fathead minnows were exposed to individual chemicals (with chemical analyzes) and sampled after 4, 7, 14, and 21 d of exposure. Wet weight, total length, condition factor, and whole-body homogenate concentrations of vitellogenin (VTG) were determined. Estrogens and antiestrogens were detected in this screen by virtue of the VTG response (an elevation or suppression, respectively) after 14 d. The study showed that the use of VTG concentrations in mixed-sex juvenile fish provides a sensitive and robust assay for the detection of both estrogenic and antiestrogenic chemicals, with widely divergent potencies.
Population responses of the freshwater amphipodGammarus pulex(L.) to an environmental estrogen, 17α-ethinylestradiol
Authors: Watts Matthew M. , Pascoe David , Carroll Kathleen
Published: March 2010

The effects of the environmental estrogen 17α-ethinylestradiol (EE) on mixed populations of 90 individual Gammarus pulex were examined following a 100-d exposure in a flow-through system. Counts of total animal numbers revealed that, in all treatment groups, population size dramatically increased due to recruitment, with neonate and juvenile gammarids the most abundant. At concentrations of 1 and 10 μg/L EE, the recorded mean population sizes of 385 and 411, respectively, were significantly greater (p = 0.018) than the control (169). Mean population sizes in the solvent control (257) and 100 ng/L EE treatment (267) were not significantly different (p > 0.05) from the control. In addition to total counts, detailed image analysis of each individual animal allowed the assessment of length—frequency distributions, adult sex ratio, number of precopula pairs/ovigerous females, and measurement of secondary antenna and gnathopod length (secondary sex characteristics). The sex ratio of adults at 100 ng, 1 μg, and 10 μg/L EE was greater than 2:1 (female:male), and significantly more females (p = 0.008) were recorded at these concentrations compared with the control. The number of male adults, precopula guarding pairs, and ovigerous females did not differ between treatments (p > 0.05). Secondary antennal and gnathopod length in males was consistently greater than in females (p ≤ 0.001), but comparison between groups revealed no difference in these parameters.
Polychlorinated dibenzo-p-dioxins and dibenzofurans and dioxinlike polychlorinated biphenyls in sediments and mussels at three sites in the lower Great Lakes, North America
Authors: Marvin Christopher H. , Howell E. Todd , Kolic Terry M. , Reiner Eric J.
Published: March 2010

Levels of contaminants including polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), non-ortho-substituted and mono-ortho-substituted dioxinlike polychlorinated biphenyls (DLPCBs) were determined in sediments and freshwater mussels (Dreissena spp. and Elliptio complanata) at three sites in the lower Great Lakes (North America). Impacts of mussel colonization on sediment quality were investigated by comparing contaminant levels in colonized sediment with levels in sediment in the same area that was not colonized, but exposed to similar environmental conditions. Significant impacts on contaminant levels of colonized sediment, compared to noncolonized sediment, were observed at two sites exhibiting high mussel population densities (Fort Erie, eastern Lake Erie, ON, Canada, 2.2 kg/m2 dry wt biomass, and Port Dalhousie, western Lake Ontario, Ontario, Canada, 6.1 kg/m2 dry wt biomass); these differences were not observed at a site with lower mussel densities (Bay of Quinte, eastern Lake Ontario, Ontario, Canada, 0.7 kg/m2). Total organic carbon and contaminant concentrations were statistically significantly greater in colonized sediment, compared to noncolonized sediment, at the two impacted sites. Areal estimates of PCDD/PCDF and DLPCB toxicity equivalents (TEQs) in mussel biomass at the three sites averaged 0.16% and 3.3%, respectively, of the TEQs in the top 3 cm of sediment, indicating that the sediments were the primary sink for contaminants. The observed differences between colonized and noncolonized sediment suggest that Dreissena are capable of influencing the chemical properties of sediment they colonize.
Predicting amphipod toxicity from sediment chemistry using logistic regression models
Authors: Field L. Jay , MacDonald Donald D. , Norton Susan B. , Ingersoll Christopher G. , Severn Corinne G. , Smorong Dawn , Lindskoog Rebekka
Published: March 2010

Individual chemical logistic regression models were developed for 37 chemicals of potential concern in contaminated sediments to predict the probability of toxicity, based on the standard 10-d survival test for the marine amphipods Ampelisca abdita and Rhepoxynius abronius. These models were derived from a large database of matching sediment chemistry and toxicity data, which includes contaminant gradients from a variety of habitats in coastal North America. Chemical concentrations corresponding to a 20, 50, and 80% probability of observing sediment toxicity (T20, T50, and T80 values) were calculated to illustrate the potential for deriving application-specific sediment effect concentrations and to provide probability ranges for evaluating the reliability of the models. The individual chemical regression models were combined into a single model, using either the maximum (PMax model) or average (PAvg model) probability predicted from the chemicals analyzed in a sample, to estimate the probability of toxicity for a sample. The average predicted probability of toxicity (from the PMax model) within probability quartiles closely matched the incidence of toxicity within the same ranges, demonstrating the overall reliability of the PMax model for the database that was used to derive the model. The magnitude of the toxic effect (decreased survival) in the amphipod test increased as the predicted probability of toxicity increased. Users have a number of options for applying the logistic models, including estimating the probability of observing acute toxicity to estuarine and marine amphipods in 10-d toxicity tests at any given chemical concentration or estimating the chemical concentrations that correspond to specific probabilities of observing sediment toxicity.
Lizard cholinesterases as biomarkers of pesticide exposure: Enzymological characterization
Authors: Sanchez-Hernandez Juan C. , Sanchez Beatriz Moreno
Published: March 2010

Here we report the results of a study conducted to elucidate the enzymological characteristics of lizard cholinesterases (ChEs) in order to use them as potential biomarkers for pesticide exposure. Serum and brain tissue of the lizard Gallotia galloti were used as ChE sources and in vitro assays were performed to identify acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) activities. The pH, substrate concentration, and specificity for ChE assays as well as the response of serum BChE to the reactivating agent pyridine-2-aldoxime methochloride (2-PAM) were also investigated in order to assess the possibilities of this methodology in biomonitoring programs. By the use of selective substrates and the inhibitor tetraisopropyl pyrophosphoramide, AChE and BChE activities were identified in lizard serum, while brain contained solely AChE. Likewise, butyrylthiocholine iodide was the optimum substrate for determining BChE activity and acetylthiocholine iodide for assaying both serum and brain AChE activities. The optimal ranges of pH and substrate concentrations were 7.5 to 8.0 and 5 to 10 mM, respectively. Serum was incubated with different doses of the organophosphorus (OP) compounds dichlorvos and paraoxon and subsequently incubated in the presence of two concentrations of 2-PAM (2 × 10−2 or 2 × 10−4 M). Reactivation rate of phosphorylated BChE was related to the degree of inhibition of BChE and the dose of 2-PAM. It was found that a 90-min incubation time with 2 × 10−4 M of 2-PAM satisfactorily increased the OP-inhibited BChE activity. The enzymological properties of serum BChE activity and its in vitro reactivation in the presence of 2-PAM represent the initial justification for its use in monitoring OP contamination in the field.
Role of metalloporphyrin core metals in the mediated reductive dechlorination of tetrachloroethylene
Authors: Dror Ishai , Schlautman Mark A.
Published: March 2010

A promising approach to abiotically dechlorinate a variety of chlorinated organic contaminants under reducing conditions is to utilize porphyrins or other tetrapyrrole macrocycles as electron transfer mediators/shuttles for catalyzing their reduction. In this study, various experimental approaches were used to elucidate the role of porphyrin core metals in the reductive dechlorination of tetrachloroethylene (PCE). The importance of specific core metals for the reactivity of a porphyrin and its mediated reaction mechanisms was demonstrated by inserting different metals into metallo tetrakis (N-methyl-4-4 pyridiniumyl) porphyrin (TMPyP). No PCE dechlorination was observed when the free-base (i.e., no core metal) and iron core metal forms of TMPyP were utilized. When using nickel or cobalt TMPyP, reductive dechlorination of PCE occurred but appeared to follow different pathways for the two metals based on product analyses. Physical (e.g., steric) considerations suggest that direct contact between a porphyrin core metal and PCE may be limited and therefore that the entire metalloporphyrin molecule should be viewed as a functional system in which the organic macrocycle has an active part in reductive dechlorination reactions. This view is supported by the fact that slight changes in the functional groups on a porphyrin macrocycle, particularly those far removed from the core metal itself, greatly affected the reactivity and mechanism of the porphyrin. Solution conditions also had a major effect on porphyrin reactivities, to the extent that a nonreactive metalloporphyrin could be activated merely by adjusting the pH of the solution or by adding a small amount of cosolvent. The collective results of this study suggest that fine tuning of naturally occurring metalloporphyrin complexes and/or their environments can enhance the catalyzed detoxification of chlorinated contaminants in many natural and engineered environmental systems.
Sorption of linear alkylbenzene sulfonate to soil components and effects on microbial iron reduction
Authors: Kristiansen Inge Broberg , de Jonge Hubert , Nørnberg Per , Mather-Christensen Ole , Elsgaard Lars
Published: March 2010

When sewage sludge is applied to arable land, linear alkylbenzene sulfonate (LAS) is released into the environment. In soils, LAS has been shown to impede microbial processes, such as bacterial iron reduction. The aim of the present study was to quantify LAS adsorption and desorption to agricultural soils and iron oxides and relate this to the inhibition of microbial iron reduction. Two agricultural soils were used, namely, Askov (coarse sandy loam soil) and Lundgaard (coarse sandy soil). In both soils, LAS inhibited microbial iron reduction even at low LAS concentrations with 10% effect concentrations of 6 to 7 and 26 to 32 mg LAS/kg dry-weight soil for Lundgaard and Askov soil, respectively. The sorption isotherms showed that sorption of LAS to iron oxides was 10 to 100 times stronger than sorption to the agricultural soils. Also, it appeared that at low LAS concentrations (<10 mg/kg dry-wt soil), Lundgaard soil adsorbed approximately 10 times more LAS than Askov soil. Thus, the inhibitory effect of LAS on microbial iron reduction was highest in the Lundgaard soil, which exhibited both the strongest sorption and the lowest desorption of the two soils. A possible hypothesis to explain this correlation was that LAS toxicity toward bacterial iron reduction was, at least partly, caused by LAS adsorbed to iron oxides, which could interfere with transfer of electrons between the bacteria and their respiratory electron acceptor.
Toward a unified approach to dose–response modeling in ecotoxicology
Authors: Ritz Christian
Published: March 2010

This study reviews dose–response models that are used in ecotoxicology. The focus lies on clarification of differences and similarities between models, and as a side effect, their different guises in ecotoxicology are unravelled. A look at frequently used dose–response models reveals major discrepancies, among other things in naming conventions. Therefore, there is a need for a unified view on dose–response modeling in order to improve the understanding of it and to facilitate communication and comparison of findings across studies, thus realizing its full potential. This study attempts to establish a general framework that encompasses most dose–response models that are of interest to ecotoxicologists in practice. The framework includes commonly used models such as the log-logistic and Weibull models, but also features entire suites of models as found in various guidance documents. An outline on how the proposed framework can be implemented in statistical software systems is also provided. Environ. Toxicol. Chem. 2010;29:220–229. © 2009 SETAC
Evaluation of hexavalent chromium in sediment pore water of the Hackensack River, New Jersey, USA
Authors: Driscoll Susan Kane , McArdle Margaret E. , Plumlee Megan H. , Proctor Deborah
Published: March 2010

Pore water was collected from in situ passive samplers in Hackensack River sediments adjacent to a chromite ore processing residue site in Kearny, New Jersey. Although the sediments at this site contained more than 3,000 mg/kg of total chromium (Cr) and shallow groundwater adjacent to the shore contained more than 1,000 µg/L of hexavalent Cr [Cr(VI)], concentrations of dissolved total Cr and Cr(VI) in pore water (PW) samples were less than ambient water quality criteria for Cr(VI) (50 µg/L). Concentrations of dissolved total Cr in pore water ranged from <2.0 to 5.3 µg/L, while Cr(VI) was not detected (<10 µg/L). These findings are consistent with previous studies, which demonstrated limited bioavailability and toxicity of Cr in sediment at this site and others with similar conditions. Environ. Toxicol. Chem. 2010;29:617–620. © 2009 SETAC
Accumulation and DNA damage in fathead minnows (Pimephales promelas) exposed to 2 brominated flame-retardant mixtures, Firemaster® 550 and Firemaster® BZ-54
Authors: Bearr Jonathan S. , Stapleton Heather M. , Mitchelmore Carys L.
Published: March 2010

Firemaster® 550 and Firemaster® BZ-54 are two brominated formulations that are in use as replacements for polybrominated diphenyl ether (PBDE) flame retardants. Two major components of these mixtures are 2,3,4,5-tetrabromo-ethylhexylbenzoate (TBB) and 2,3,4,5-tetrabromo-bis(2-ethylhexyl) phthalate (TBPH). Both have been measured in environmental matrices; however, scant toxicological information exists. The present study aimed to determine if these brominated flame-retardant formulations are bioavailable and adversely affect DNA integrity in fish. Fathead minnows (Pimephales promelas) were orally exposed to either FM 550, FM BZ54, or the nonbrominated form of TBPH, di-(2-ethylhexyl) phthalate (DEHP) for 56 d and depurated (e.g., fed clean food) for 22 d. At several time points, liver and blood cells were collected and assessed for DNA damage. Homogenized fish tissues were extracted and analyzed on day 0 and day 56 to determine the residue of TBB and TBPH and the appearance of any metabolites using gas chromatography-electron-capture negative ion mass spectrometry (GC/ECNI-MS). Significant increases (p < 0.05) in DNA strand breaks from liver cells (but not blood cells) were observed during the exposure period compared with controls, although during depuration these levels returned to control. Both parent compounds, TBB and TBPH, were detected in tissues at approximately 1% of daily dosage along with brominated metabolites. The present study provides evidence for accumulation, metabolism, and genotoxicity of these new formulation flame retardants in fish and highlights the potential adverse effects of TBB- and TBPH-formulated fire retardants to aquatic species. Environ. Toxicol. Chem. 2010;29:722–729. © 2009 SETAC
β‐catenin mediates insulin‐like growth factor‐I actions to promote cyclin D1 mRNA expression, cell proliferation and survival in oligodendroglial cultures
Authors: Ye Ping , Hu Qichen , Liu Hedi , Yan Yun , D'ercole A. Joseph
Published: March 2010

By promoting cell proliferation, survival and maturation insulin‐like growth factor (IGF)‐I is essential to the normal growth and development of the central nervous system. It is clear that IGF‐I actions are primarily mediated by the type I IGF receptor (IGF1R), and that phosphoinositide 3 (PI3)‐Akt kinases and MAP kinases signal many of IGF‐I‐IGF1R actions in neural cells, including oligodendrocyte lineage cells. The precise downstream targets of these signaling pathways, however, remain to be defined. We studied oligodendroglial cells to determine whether β‐catenin, a molecule that is a downstream target of glycogen synthase kinase‐3β (GSK3β) and plays a key role in the Wnt canonical signaling pathway, mediates IGF‐I actions. We found that IGF‐I increases β‐catenin protein abundance within an hour after IGF‐I‐induced phosphorylation of Akt and GSK3β. Inhibiting the PI3‐Akt pathway suppressed IGF‐I‐induced increases in β‐catenin and cyclin D1 mRNA, while suppression of GSK3β activity simulated IGF‐I actions. Knocking‐down β‐catenin mRNA by RNA interference suppressed IGF‐I‐stimulated increases in the abundance of cyclin D1 mRNA, cell proliferation, and cell survival. Our data suggest that β‐catenin is an important downstream molecule in the PI3‐Akt‐GSK3β pathway, and as such it mediates IGF‐I upregulation of cyclin D1 mRNA and promotion of cell proliferation and survival in oligodendroglial cells. © 2010 Wiley‐Liss, Inc.
Enhanced white matter tracts integrity in children with abacus training
Authors: Hu Yuzheng , Geng Fengji , Tao Lixia , Hu Nantu , Du Fenglei , Fu Kuang , Chen Feiyan
Published: March 2010

Experts of abacus, who have the skills of abacus‐based mental calculation (AMC), are able to manipulate numbers via an imagined abacus in mind and demonstrate extraordinary ability in mental calculation. Behavioral studies indicated that abacus experts utilize visual strategy in solving numerical problems, and fMRI studies confirmed the enhanced involvement of visuospatial‐related neural resources in AMC. This study aims to explore the possible changes in brain white matter induced by long‐term training of AMC. Two matched groups participated: the abacus group consisting of 25 children with over 3‐year training in abacus calculation and AMC, the controls including 25 children without any abacus experience. We found that the abacus group showed higher average fractional anisotropy (FA) in whole‐brain fiber tracts, and the regions with increased FA were found in corpus callosum, left occipitotemporal junction and right premotor projection. No regions, however, showed decreased FA in the abacus group. Further analysis revealed that the differences in FA values were mainly driven by the alternation of radial rather than axial diffusivities. Furthermore, in forward digit and letter memory span tests, AMC group showed larger digit/letter memory spans. Interestingly, individual differences in white matter tracts were found positively correlated with the memory spans, indicating that the widespread increase of FA in the abacus group result possibly from the AMC training. In conclusion, our findings suggested that long‐term AMC training from an early age may improve the memory capacity and enhance the integrity in white matter tracts related to motor and visuospatial processes. Hum Brain Mapp, 2010. © 2010 Wiley‐Liss, Inc.
Cubic vertex‐transitive graphs of order 2pq
Authors: Zhou Jin‐Xin , Feng Yan‐Quan
Published: March 2010

A graph is vertex−transitive or symmetric if its automorphism group acts transitively on vertices or ordered adjacent pairs of vertices of the graph, respectively. Let G be a finite group and S a subset of G such that 1∉S and S={s−1 | s∈S}. The Cayleygraph Cay(G, S) on G with respect to S is defined as the graph with vertex set G and edge set {{g, sg} | g∈G, s∈S}. Feng and Kwak [J Combin Theory B 97 (2007), 627–646; J Austral Math Soc 81 (2006), 153–164] classified all cubic symmetric graphs of order 4p or 2p2 and in this article we classify all cubic symmetric graphs of order 2pq, where p and q are distinct odd primes. Furthermore, a classification of all cubic vertex‐transitive non‐Cayley graphs of order 2pq, which were investigated extensively in the literature, is given. As a result, among others, a classification of cubic vertex‐transitive graphs of order 2pq can be deduced. © 2010 Wiley Periodicals, Inc. J Graph Theory 65: 285–302, 2010
Hyponatremia in a patient with cryptococcal meningitis: Syndrome of inappropriate antidiuretic hormone (SIADH) or cerebral salt wasting (CSW)?
Authors: Momi Jasminder , Tang Christopher , Abcar Antoine C. , Kujubu Dean A. , Sim John J.
Published: March 2010

Journal of Hospital Medicine 2010;5:193–195. © 2010 Society of Hospital Medicine.
The ethics of the hospitalist model
Authors: Rosenbloom Adam Haley , Jotkowitz Alan
Published: March 2010

The hospitalist model was founded on the premise that it could improve the quality and reduce the cost of hospital care. Many randomized studies have all but definitively proven this original assertion. Nevertheless, the hospitalist specialty raises lingering classical ethical issues: protecting the patient‐physician relationship in an environment of increasing specialization and discontinuity of care, preserving patient autonomy and choice when structural changes are made in the provision of care, and ensuring that a model founded on efficiency and cost‐effectiveness does not erode the public trust in hospitalists to always serve their patients' best interests. This work aims to serve as an update of these initial criticisms, showing how some questions have been answered, while some have not. Journal of Hospital Medicine 2010;5:183–188. © 2010 Society of Hospital Medicine.
Hospitalist physician leadership skills: Perspectives from participants of a leadership conference
Authors: Soong Christine , Wright Scott M. , Howell Eric E.
Published: March 2010

OBJECTIVE:

To characterize how the use of behavioral contracts may serve to focus individuals' intentions to grow as leaders.

METHODS:

Between 2007 and 2008, participants of the Society of Hospital Medicine Leadership Academy courses completed behavioral contracts to identify 4 action plans they wanted to implement based on things learned at the Academy. Contracts were independently coded by 2 investigators and compared for agreement. Content analysis identified several major themes that relate to professional growth as leaders. Follow‐up surveys assessed fulfillment of personal goals.

RESULTS:

The majority of respondents were male (84; 70.0%), and most were hospitalist leaders (76; 63.3%). Their median time practicing as hospitalists was 4 years, 14 (11.7%) were Assistant Professors, and 80 (66.7%) were in private practice. Eight themes emerged from the behavioral contracts, revealing ways in which participants wished to develop: improving communication and interpersonal relations; refining vision and goals for strategic planning; developing intrapersonal leadership; enhancing negotiation skills; committing to organizational change; understanding business drivers; establishing better metrics to assess performance; and strengthening interdepartmental relationships. At follow‐up, all but 1 participant had achieved at least 1 of their personal goals.

CONCLUSIONS:

Understanding the areas that hospitalist leaders identify as “learning edges” may inform the personal learning plans of those hoping to take on leadership roles in hospital medicine. Journal of Hospital Medicine 2010;5:E1–E4. © 2010 Society of Hospital Medicine.
Exoskeletal chitin scales isometrically with body size in terrestrial insects
Authors: Lease Hilary M. , Wolf Blair O.
Published: March 2010

The skeletal system of animals provides the support for a variety of activities and functions. For animals such as mammals, which have endoskeletons, research has shown that skeletal investment (mass) scales with body mass to the 1.1 power. In this study, we ask how exoskeletal investment in insects scales with body mass. We measured the body mass and mass of exoskeletal chitin of 551 adult terrestrial insects of 245 species, with dry masses ranging from 0.0001 to 2.41 g (0.0002–6.13 g wet mass) to assess the allometry of exoskeletal investment. Our results showed that exoskeletal chitin mass scales isometrically with dry body mass across the Insecta as Mchitin = a M, where b = 1.03 ± 0.04, indicating that both large and small terrestrial insects allocate a similar fraction of their body mass to chitin. This isometric chitin‐scaling relationship was also evident at the taxonomic level of order, for all insect orders except Coleoptera. We additionally found that the relative exoskeletal chitin investment, indexed by the coefficient, a, varies with insect life history and phylogeny. Exoskeletal chitin mass tends to be proportionally less and to increase at a lower rate with mass in flying than in nonflying insects (Mflying insect chitin = −0.56 × M; Mnonflying insect chitin = −0.55 × M), and to vary with insect order. Isometric scaling (b = 1) of insect exoskeletal chitin suggests that the exoskeleton in insects scales differently than support structures of most other organisms, which have a positive allometry (b > 1) (e.g., vertebrate endoskeleton, tree secondary tissue). The isometric pattern that we document here additionally suggests that exoskeletal investment may not be the primary limit on insect body size. J. Morphol., 2010. © 2010 Wiley‐Liss, Inc.
Development of the cypriniform protrusible jaw complex in Danio rerio: Constructional insights for evolution
Authors: Staab Katie Lynn , Hernandez L. Patricia
Published: March 2010

Studies on the evolution of complex biological systems are difficult because the construction of these traits cannot be observed during the course of evolution. Complex traits are defined as consisting of multiple elements, often of differing embryological origins, with multiple linkages integrated to form a single functional unit. An example of a complex system is the cypriniform oral jaw apparatus. Cypriniform fishes possess an upper jaw characterized by premaxillary protrusion during feeding. Cypriniforms effect protrusion via the kinethmoid, a synapomorphy for the order. The kinethmoid is a sesamoid ossification suspended by ligaments attaching to the premaxillae, maxillae, palatines, and neurocranium. Upon mouth opening, the kinethmoid rotates as the premaxillae move anteriorly. Along with bony and ligamentous elements, there are three divisions of the adductor mandibulae that render this system functional. It is unclear how cypriniform jaws evolved because although the evolution of sesamoid elements is common, the incorporation of the kinethmoid into the protrusible jaw results in a function that is atypical for sesamoids. Developmental studies can show how biological systems are assembled within individuals and offer clues about how traits might have been constructed during evolution. We investigated the development of the protrusible upper jaw in zebrafish to generate hypotheses regarding the evolution of this character. Early in development, the adductor mandibulae arises as a single unit. The muscle divides after ossification of the maxillae, on which the A1 division will ultimately insert. A cartilaginous kinethmoid first develops within the intermaxillary ligament; it later ossifies at points of ligamentous attachment. We combine our structural developmental data with published kinematic data at key developmental stages and discuss potential functional advantages in possessing even the earliest stages of a system for protrusion. J. Morphol. 2010. © 2010 Wiley‐Liss, Inc.
Climatic changes since the last deglaciation inferred from a lacustrine sedimentary sequence in the eastern Nanling Mountains, south China
Authors: Zhong Wei , Xue Jibin , Zheng Yanming , Ouyang Jun , Ma Qiaohong , Cai Ying , Tang Xiaohong
Published: March 2010

Two sediment cores recovered from Dahu Swamp, which is located in eastern Nanling Mountains in south China, were selected for investigation of palaeoclimatic changes. Multi‐proxy records of the two cores including lithological variation, organic carbon isotope ratio, dry bulk density, organic matter content, magnetic susceptibility, humification degree, median grain size and geochemical proxies reveal that during the last deglaciation three drier phases correspond to the Oldest, Older and Younger Dryas cooling events, and the intercalated two wetter phases synchronise with the Bølling and Allerød warming events. The Holocene Optimum, which was resulted from a strengthening of the East Asian (EA) summer monsoon, occurred in the early and mid Holocene (ca. 10–6 cal. ka BP). In the mid and late Holocene (ca. 6–3 cal. ka BP), a prevailing dry climate suggested a weakening of the EA summer monsoon. The general trend of Holocene climatic changes in this study agrees with the 25° N summer solar insolation, suggesting that orbitally induced insolation may have played an important role in the Holocene climate in the study region. Copyright © 2010 John Wiley & Sons, Ltd.
Determination and comparison of flavonoids and anthocyanins in Chinese sugarcane tips, stems, roots and leaves
Authors: Li Xinying , Yao Shun , Tu Bin , Li Xue , Jia Chunmei , Song Hang
Published: March 2010

The flavonoids and anthocyanins in Chinese sugarcane (Saccharum sinensis Roxb.) tips, stems, roots and leaves were separately analyzed by HPLC‐UV diode array detector, respectively. The results indicated that the content of flavonoids in sugarcane leaves was considerably high in comparison with previous reports in Brazil sugarcane (S. officinarum L.) leaves. Moreover, the content of flavonoids in sugarcane tips and roots was also high in comparison with sugarcane stems. For another, the content of anthocyanins in sugarcane roots was higher than that in other parts of the sugarcane, such as leaves, tips and stems. In addition, two anthocyanins, named petunidin 3‐O‐(6″‐succinyl)‐rhamnoside and cyanidin‐3‐O‐glucoside, were first identified from S. sinensis by HPLC‐UV diode array detector and HPLC‐MS/MS.
HPLC‐DAD methodology for the quantification of organic acids, furans and polyphenols by direct injection of wine samples
Authors: Pereira Vanda , Câmara José S. , Cacho Juan , Marques José C.
Published: March 2010

This article proposes a simple and sensitive HPLC method with photo‐diode array detection for the analysis of organic acids, monomeric polyphenols and furanic compounds in wine samples by direct injection. The chromatographic separation of 8 organic acids, 2 furans and 22 phenolic compounds was carried out with a buffered solution (pH 2.70) and acetonitrile as mobile phases and a difunctionally bonded C18 stationary phase, Atlantis dC18 (250×4.6 mm, 5 μm) column. The elution was performed in 12 min for the organic acids and in 60 min for the phenolic compounds, including phenolic acids, stilbenes and flavonoids. Target compounds were detected at 210 nm (organic acids, flavan‐3‐ols and benzoic acids), 254 nm (ellagic acid), 280 nm (furans and cinnamic acid), 315 nm (hydroxycinnamic acids and trans‐resveratrol) and 360 nm (flavonoids). The RSD for the repeatability test (n=5) of peak area and retention times were below 3.1 and 0.3%, respectively, for phenolics and below 1.0 and 0.2% for organic acids. The RSDs expressing the reproducibility of the method were higher than for the repeatability results but all below 9.0%. Method accuracy was evaluated by the recovery results, with averaged values between 80 and 104% for polyphenols and 97–105% for organic acids. The calibration curves, obtained by triplicate injection of standard solutions, showed good linearity with regression coefficients higher than 0.9982 for polyphenols and 0.9997 for organic acids. The LOD was in the range of 0.07–0.49 mg/L for polyphenols (cinnamic and gallic acids, respectively) and 0.001–0.046 g/L for organic acids (oxalic and lactic acids, respectively). The method was successfully used to measure and assess the polyphenolic fingerprint and organic acids profile of red, white, rosé and fortified wines.
Study of retention mechanism of imidazolium‐based ionic liquids in HPLC
Authors: Studzińska Sylwia , Buszewski Bogusław
Published: March 2010

Retention mechanism of ionic compounds is still not fully known and investigated. It concerns especially ionic liquids (ILs) and HPLC. In the present study, interactions between imidazolium ILs and stationary phases were investigated in complex manner. For that purpose, five ILs, eight packing materials (with different functional groups bonded to silica surface) and three different pH of mobile phases were chosen. A great variety of applied chromatographic columns, as well as the changes made in mobile phase, allows for the description of retention mechanism. The main interactions responsible for retention process appear to be electrostatic, π–π and hydrophobic. Such complex results are presented for the first time.
Characterization of PEG in monomethyl ethers of PEG by 2‐D LC
Authors: Ahmed Hasnat , Trathnigg Bernd
Published: March 2010

PEGs present in samples of the corresponding monomethyl ethers are analyzed by 2‐D LC with LC at critical conditions as the first and liquid adsorption chromatography as the second dimension. The fractions from the first dimension are transferred to the second one by heart‐cutting using a ten‐port valve. The efficiency of the separation is dramatically improved by adding water to the eluate from the first dimension before the switching valve in order to have a weaker eluent in the fraction than that of the second dimension. By this procedure, the fractions are focussed and reconcentrated. The molar mass distribution of the PEG fraction can be determined with good accuracy even at very low amounts of PEG in the PEG‐monomethyl ethers (down to 0.5%).
Psychological well‐being in rheumatoid arthritis: a review of the literature
Authors: Gettings Lynda
Published: March 2010

The psychological well‐being of patients with rheumatoid arthritis (RA) is an important issue, and the advent of measurement tools has led to a better understanding of the mental aspects associated with this chronic illness. Patients with RA are more likely to suffer from anxiety, depression and low self‐esteem, with high levels of associated mortality and suicide. The loss of the ability to carry out daily functions owing to RA is also associated with the onset of depressive symptoms. Furthermore, the psychological effects of RA can extend to the partners, families and carers of sufferers. Conventional treatment has focused on treating the symptoms of RA and containment of disease progression, but may not necessarily address the psychological issues associated with the condition. Furthermore, patient perception of RA and of the support offered to them can cause further unnecessary psychological distress. Access to psychological support for RA patients has been shown to be inconsistent and haphazard. It is now being recognized that what is needed is a multidisciplinary team approach to treat psychological distress in RA alongside conventional treatment, involving alternative therapies tailored to the psychological needs of the patient. The benefits of treatments such as cognitive behavioural therapy, meditation and exercise are clear and these treatments should be actively encouraged, thereby enabling patients with RA to better manage the psychological burden associated with this chronic condition. Copyright © 2010 John Wiley & Sons, Ltd.
In vivo chlorine‐35, sodium‐23 and proton magnetic resonance imaging of the rat brain
Authors: Kirsch Stefan , Augath Mark , Seiffge David , Schilling Lothar , Schad Lothar R.
Published: March 2010

In this study we demonstrate the feasibility of combined chlorine‐35, sodium‐23 and proton magnetic resonance imaging (MRI) at 9.4 Tesla, and present the first in vivo chlorine‐35 images obtained by means of MRI. With the experimental setup used in this study all measurements could be done in one session without changing the setup or moving the subject. The multinuclear measurement requires a total measurement time of 2 h and provides morphological (protons) and physiological (sodium‐23, chlorine‐35) information in one scanning session. Chlorine‐35, sodium‐23 and high resolution proton images were acquired from a phantom, a healthy rat and from a rat displaying a focal cerebral infarction. Compared to the healthy tissue a signal enhancement of a factor of 2.2 ± 0.2 in the chlorine‐35 and a factor of 2.9 ± 0.6 in the sodium‐23 images is observed in the areas of infarction. Exemplary unlocalized measurement of the in vivo longitudinal and transversal relaxation time of chlorine‐35 in a healthy rat showed multi‐exponential behaviour. A biexponential fit revealed a fast and a slow relaxing component with T1,a = (1.7 ± 0.4) ms, T1,b = (25.1 ± 1.4) ms, amplitudes of A = 0.26 ± 0.02, (1–A) = 0.74 ± 0.02 and T2,a = (1.3 ± 0.1) ms, T2,b = (11.8 ± 1.1) ms, A = 0.64 ± 0.02, (1–A) = 0.36 ± 0.02. Combined proton, sodium‐23 and chlorine‐35 MRI may provide a new approach for non‐invasive studies of ionic regulatory processes under physiological and pathological conditions in vivo. Copyright © 2010 John Wiley & Sons, Ltd.