bluuebunny/crossref_metadata_2025 huggingface dataset:
Spatial, temporal, and dietary determinants of organic contaminants in nestling tree swallows in Point Pelee National Park, Ontario, Canada
Authors: Smits Judit E. G. , Bortolotti Gary R. , Sebastian Mary , Ciborowski Jan J. H.
Published: November 2005

Point Pelee National Park of Canada in southwestern Ontario, an important migratory route andvital breeding area for many birds, has localized areas of organochlorine (OC) pesticide contamination from agricultural production during the 1950s and 1960s. During 2001 and 2002, we investigated movement of persistent contaminants through the food web with the insectivorous tree swallow (Tachycineta bicolor) as a sentinel. The a priori site classifications, contaminated or reference, were based on soil residues of dichlorodiphenyltrichloroethane (DDT) and its breakdown products (∑DDT), dieldrin, and other OC pesticides. In 2001, all nestling tissue samples were pooled by site, and residue levels did not reflect the soil contaminant status. To improve sampling accuracy in 2002, tissue residues were determined from birds in individual nests. This showed OC pesticides to be higher in samples from contaminated sites compared with reference sites (p = 0.031). Polychlorinated biphenyls (PCBs), which were not detected in soil samples, were present in the nestlings and were not related to site of origin (p = 0.422). In 2002, dietary samples were collected from nestlings and identified to taxon, and representative insects collected from nesting sites were analyzed for PCBs and other OCs. Consumption of terrestrial prey was positively correlated with tissue residues of ∑DDT (p = 0.006), whereas PCBs came from aquatic prey, Hexagenia mayflies (p = 0.003). Dietary details proved valuable in this study of contaminant transfer in insectivorous vertebrates.
Extracellular signal-regulated kinase-signaling-dependent G2/M arrest and cell death in murine macrophages by cadmium
Authors: Kim Jiyoung , Kim Sang Hyun , Johnson Victor J. , Sharma Raghubir P.
Published: November 2005

Cadmium is a nonessential heavy metal and a well-known persistent environmental pollutant. I causes a variety of toxic effects, including immunotoxicity. The exact mechanism of its cellular effects still is unclear. Cell-cycle regulation is an important factor that modulates cell death; however, cadmium-mediated cell-cycle arrest leading to cell death in murine macrophages has not been investigated. Cadmium at 20 μM induced both apoptotic and necrotic death in murine macrophage (J774A.1) cultures at 24 h. Cadmium at 20 μM triggered re-entry of G0/G1 to the next phase and increased the number of cells in the G2/M phase at 24 h. Phosphorylation of extracellular signal-regulated kinase (ERK) correlated with the cyclin-dependent kinase inhibitor p21WAF1/CIP1 induction. Inhibition of ERK activation by PD98059 resulted in G0/G1 arrest and partially released the cadmium-mediated G2/M arrest. Inhibition of ERK phosphorylation by PD98059 strongly attenuated cadmium-induced necrotic cell death, but did not prevent caspase-3 activation and DNA fragmentation. Necrosis rather than apoptosis was caused by cadmium-induced ERK signaling in J774A.1 cells. A scavenger of reactive oxygen species (ROS), N-acetylcystein, decreased cadmium-induced ERK activation and necrotic cell death, suggesting that cadmium induces the ROS-ERK-p21WAF1/CIP1 signaling pathway, leading to G2/M arrest and cell death. These findings may be important in further understanding the cellular mechanisms of cadmium toxicity to provide information to assess objectively risk for this metal.
Reproductive success and contaminants in tree swallows (Tachycineta bicolor) breeding at a wastewater treatment plant
Authors: Dods Patti L. , Birmingham Erinn M. , Williams Tony D. , Ikonomou Michael G. , Bennie Donald T. , Elliott John E.
Published: November 2005

The uptake and effects of contaminants were measured in the insectivorous tree swallow (Tachycineta bicolor) at a wastewater treatment site. The study examined reproductive, immunological, and growth endpoints in tree swallows exposed to chlorinated hydrocarbon contaminants and to 4-nonylphenol in wastewater lagoons at the Iona Wastewater Treatment Plant, Vancouver (BC, Canada). Clutch size was significantly lower in tree swallows breeding at Iona Island in 2000 and 2001 compared to the reference site. In 2000, fledging success was significantly lower and mean mass of nestling livers was significantly higher in the tree swallows breeding at the Iona Island Wastewater Treatment Plant. Additional factors that may influence reproductive success, such as parental provisioning and diet composition, did not differ significantly between sites. Levels of 4-nonylphenol detected in sediment and insects were elevated at the Iona Island Wastewater Treatment Plant (2000: lagoon sediment 82,000 ng/g dry wt, insects 310 ng/g wet wt; 2001: lagoon sediment 383,900 ng/g dry wt, insects 156 ng/g wet wt) compared to the reference site (2000: pond sediment 1,100 ng/g dry wt, insects not sampled; 2001: pond sediment 642 ng/g dry wt, insects 98 ng/g wet wt). These results indicate that tree swallows might be a useful indicator species for exposure to 4-nonylphenol at wastewater treatment sites; however, further work is necessary to determine the extent of uptake and effects of 4-nonylphenol in riparian insectivorous birds.
Light as a confounding factor for toxicity assessment of complex contaminated sediments
Authors: Grote Matthias , Brack Werner , Walter Helge A. , Altenburger Rolf
Published: November 2005

Polycyclic aromatic hydrocarbons (PAHs) are contaminants often found in sediments. Their relevant contribution to toxic effects induced by environmental samples has been demonstrated using effect-directed analysis (EDA). Toxicity of PAHs previously has been reported to depend on light conditions. The aim of this study was to analyze the influence of simulated sunlight, in comparison to standard algal growth light, on the toxicity of samples, in which PAHs were identified as major toxicants using EDA. Additionally, toxicity of identified toxicants and mixtures of these compounds were assessed. It can be shown that the samples, the PAH compounds, and the created mixtures exhibit photoenhanced toxicity. The combined effects of the mixtures can be predicted using the model of concentration addition. This is surprising because different modes of action have been reported to contribute to phototoxicity of the identified toxicants. For the confirmation step in EDA, the toxicity assessment under simulated sunlight reveals that less of the samples' toxicity can be explained by the identified compounds, compared to the assessment conducted under standard growth light. Finally, the relevance of light conditions in the toxicity assessment is demonstrated for eight out of 13 transect samples of sediment extracts from river Elbe, Germany.
Environmental fate of the antifouling compound zinc pyrithione in seawater
Authors: Grunnet Katja S. , Dahllof Ingela
Published: November 2005

To perform a thorough risk assessment of the new antifouling compound zinc pyrithione (ZnPT2), additional information regarding the fate of the compound is needed. The present study examined the recovery and transchelation of ZnPT2 in controlled laboratory experiments, photodegradation experiments, and a fate study in a large-scale field experiment. Chemical analyses were performed using a newly developed method for simultaneous analyses of ZnPT2 and copper pyrithione (CuPT2). Furthermore, two antifouling paints containing ZnPT2 were examined for the fate of leaching biocide. Naturally occurring ligands and metals in seawater influence the stability of ZnPT2. The presence of free Cu2+, which is present naturally in the seawater or is released from copper-containing paints, results in a partial transchelation of ZnPT2 into CuPT2. A complete transchelation of ZnPT2 into CuPT2 was observed when Cu2+ was present at an equimolar concentration in the absence of interfering ligands. When ZnPT2 was leached from antifouling paints containing both ZnPT2 and Cu2O, CuPT2 was found, with no trace of ZnPT2. Photodegradation was low in natural waters and absent from 1 m or more below the surface. The results show that ZnPT2 has a low persistence in seawater when leached from antifouling paints. However, the more stable and toxic transchelation product CuPT2 is formed, which has the potential to accumulate in the sediments and, therefore, should be included in both chemical analysis and risk assessment of ZPT2.
Comparative sediment quality guideline performance for predicting sediment toxicity in Southern California, USA
Authors: Vidal Doris E. , Bay Steven M.
Published: November 2005

Several types of sediment quality guidelines (SQGs) are used by multiple agencies in southern California (USA) to interpret sediment chemistry data, yet little information is available to identify the best approaches to use. The objective of this study was to evaluate the predictive ability of five SQGs to predict the presence and absence of sediment toxicity in coastal southern California: the effects range-median quotient (ERMq), consensus moderate effect concentration (consensus MEC), mean sediment quality guideline quotient (SQGQ1), apparent effects threshold (AET), and equilibrium partitioning (EqP) for organics. Large differences in predictive ability among the SQGs were obtained when each approach was applied to the same southern California data set. Sediment quality guidelines that performed well in identifying nontoxic samples were not necessarily the best predictors of toxicity. In general, the mean ERMq, SQGQ1q, and consensus MECq approaches had a better overall predictive ability than the AET and EqP for organics approaches. In addition to evaluating the predictive ability of SQGs addressing chemical mixtures, the effect of an individual SQG value (DDT) was also evaluated for the mean ERMq with and without DDT. The mean ERMq without DDT had a better ability to predict toxic samples than the mean ERMq with DDT. Similarities in discriminatory ability between different approaches, variations in accuracy among SQG values for some chemicals, and the presence of complex mixtures of contaminants in most samples underscore the need to apply SQGs in combination, such as the mean quotient. Management objectives and SQG predictive ability using regional data should be determined beforehand so that the most appropriate SQG approach and critical values can be identified for specific applications.
4-nonylphenol-induced toxicity and apoptosis in Hydra attenuata
Authors: Pachura Sophie , Cambon Jean-Pierre , Blaise Christian , Vasseur Paule
Published: November 2005

Effects of 4-nonylphenol (4-NP) onthe morphology and survival of the cnidarian Hydra attenuata were studied under acute exposure conditions. The lethal concentration value inducing 50% mortality after 96 h was 97.5 ± 20 μg/L, whereas the lethal concentration value inducing 10% mortality after 96 h was 64 ± 25.5 μg/L. The no-observed-effect concentration based on morphological criteria was less than 25 μg/L. Hydra was one of the most sensitive freshwater invertebrate species behind the amphipod Hyalella azteca. Toxicity effects appeared rapidly and did not evolve substantially between 24 and 96 h of exposure. Induction of apoptosis was registered during the first hour of exposure to 4-NP at lethal concentrations, indicating rapid effects of the chemical. Abnormal increase of apoptosis may explain the acute toxicity of 4-NP in hydra. Results show that hydra viability is affected in the short term at 4-NP concentrations normally found in contaminated sites, but not at those concentrations reflecting lower levels of environmental contamination.
Improved empirical models describing hormesis
Authors: Cedergreen Nina , Ritz Christian , Streibig Jens Carl
Published: November 2005

During the past two decades, the phenomenon of hormesis has gained increased recognition. To promote research in hormesis, a soudund statistical quantification of important parameters, such as the level and significance of the increase in response and the range of concentration where it occurs, is strongly needed. Here, we present an improved statistical model to describe hormetic dose—response curves and test for the presence of hormesis. Using the delta method and freely available software, any percentage effect dose or concentration can be derived with its associated standard errors. Likewise, the maximal response can be extracted and the growth stimulation calculated. The new model was tested on macrophyte data from multiple-species experiments and on laboratory data of Lemna minor. For the 51 curves tested, significant hormesis was detected in 18 curves, and for another 17 curves, the hormesis model described that data better than the logistic model did. The increase in response ranged from 5 to 109%. The growth stimulation occurred at an average dose somewhere between zero and concentrations corresponding to approximately 20 to 25% of the median effective concentration (EC50). Testing the same data with the hormesis model proposed by Brain and Cousens in 1989, we found no significant hormesis. Consequently, the new model is shown to be far more robust than previous models, both in terms of variation in data and in terms of describing hormetic effects ranging from small effects of a 10% increase in response up to effects of an almost 100% increase in response.
Slow desorption behavior of one highly resistant aromatic amine in Lake Macatawa, Michigan, USA, sediment
Authors: Chen Shihua , Nyman Marianne C.
Published: November 2005

The desorption behavior of benzidine from Lake Macatawa (Holland, MI, USA) sediment was investigated in this study using batch solvent extraction method. Seven solvents were tested as the extracting reagents: Deionized water (DI), calcium chloride in DI (CaCl2), sodium hydroxide in DI (NaOH), acetonitrile (ACN), a mixture of acetonitrile and ammonium acetate in DI (ACNNH4OAc), methanol (MeOH), and hydrochloric acid in DI (HCl). These solvents are proposed to react with sediment-associated benzidine by different mechanisms (e.g., cation exchange, hydrophobic partitioning, and covalent binding). Three sets of sorption isotherm experiments were conducted separately in these seven solvents with a 7-d, three-week, and two-month contact time. The results demonstrated nonlinear isotherms with Freundlich 1/n values varying from 0.25 to 0.52. The desorption behavior of benzidine in the solvents was evaluated after the sorption of benzidine onto the sediment with same contact times of 7 d, three weeks, and two months. A two-stage model subsequently was applied to simulate the experimental data. The rapidly desorbing rate constants were on the order of one to two per day for ACN, ACN-NH4OAc, and NaOH solvents, and the slowly desorbing rate constants were on the order of 10−5 to 10−4/d. Sequential desorption experiment demonstrated low total extraction efficiency of less than 40%. Both the observed sorption and desorption phenomena suggested that hysteresis and/or mass-transfer limited diffusion may result in the slow desorption behavior observed in this study.
Measuring sulfide accumulation in diffusive gradients in thin films by means of purge and trap followed by ion-selective electrode
Authors: Rearick Michael S. , Gilmour Cynthia C. , Heyes Andrew , Mason Robert P.
Published: November 2005

A procedure for measuring in situ sulfide concentrations by coupling diffusive gradients in thin films (DGT) to solid-state ion-selective electrodes (ISE) is described and evaluated. Laboratory tests were performed to evaluate the coupling of these techniques, and these results were compared to the previously used methods of computer imaging densitometry (CID) and methylene blue. An average elution efficiency of 89%, as detected by ISE, was determined for a series of solutions containing amounts of sulfide ranging from 0.009 to 2.50 μmol. The validity of the standard mass-transfer equation for sulfide accumulation by DGT probes and subsequent detection by ISE was tested by measuring the mass of sulfide collected over time and with respect to varying diffusive gel thicknesses. Regressions of the sulfide mass accumulation versus the independent variables of time and inverse diffusive thickness proved to be linear. The use of DGT coupled to ISE provides a preconcentration method for sulfide that improves the detection limit (DL) over other techniques. This alternative method provides quantitative measurements of DGT-captured sulfide from solutions with a detection limit of at least 0.1 μmol/L for a 24-h deployment. The DGT technique also provides potential advantages in understanding sulfide speciation over existing methods.
Effects of selected biocides used in the disinfection of cooling towers on toxicity and bioaccumulation in Artemia larvae
Authors: Bartolomé Maria Carmen , Sánchez-Fortún Sebastián
Published: November 2005

This paper reports the acute toxicity of three biocides used in the disinfection of cooling towers, tetrakis(hydroxymethyl) phosphonium chloride (THPC), trichloroisocyanuric acid (TCIC), and sodium bromide (NaBr), on Artemia larvae, their effect on the phototactic response of this organism, and the potential of bioaccumulation in this species. The 24-h median lethal concentration (LC50) values for these biocides with respect to 24-, 48-, and 72-h-old Artemia, determined by static bioassays, showed the following rank order of toxicity: THPC < TCIC < NaBr. An age-dependent increase in sensitivity was seen for each compound. All three biocides reduced the phototactic response of 24-h-old Artemia larvae in 24-h static bioassays; the median inhibitory concentration ratios obtained were 30 to 40 times lower than their respective 24-h LC50 values. The results suggest that phototaxis bioassays could provide the speed and simplicity required for screening many potential pollutants for harmful effects. The bioconcentration factors obtained for Artemia larvae exposed to 10% LC50 for 168 h in renewal assays were 93.75, 1.67, and 0.23 for THPC, TCIC, and NaBr, respectively. This shows these biocides pose no bioaccumulation risk in this organism, although the value of 93.75 obtained for THPC is close to the threshold above which such a risk is considered to exist.
A comparison of the lethal and sublethal toxicity of organic chemical mixtures to the fathead minnow (Pimephales promelas)
Authors: Broderius Steven J. , Kahl Michael D. , Elonen Gregory E. , Hammermeister Dean E. , Hoglund Marilynn D.
Published: November 2005

The joint toxic effects of known binary and multiple organic chemical mixtures to the fathead minnow (Pimephales promelas) were defined at both the 96-h 50% lethal effect concentration (LC50) and sublethal (32-d growth) response levels for toxicants with a narcosis I, narcosis II, or uncoupler of oxidative phosphoralation mode of toxic action. Experiments were designed to define the degree of additive joint toxicity for mixtures of specific xenobiotics that are believed to act through a similar or different primary mode of toxic action. Our results support the general conclusion that concentration addition is expected for the joint toxicity of similarly acting toxicants. When chemicals were thought to act by a dissimilar mechanism, the combined effects we observed at both of the response levels tested were less than predicted by concentration addition, but usually more toxic than that predicted by the independent action/response addition model. It was demonstrated in multichemical mixtures that several toxicants can act together in a nearly additive fashion to produce effects even when they are present at concentrations below their individual no-observed-effect concentration. Concentration-response relationships for test chemicals at both the lethal and sublethal responses were defined for each of the three modes of toxic action studied. When normalized for potency, it was observed that one relationship could be defined to predict lethality to juvenile fathead minnows when exposed to individual chemicals with either a narcosis I, narcosis II, or uncoupler mode of toxic action. These sublethal relationships were similar for the narcosis I and narcosis II test chemicals, but a steeper response was observed for tests conducted with uncouplers.
Behavioral response of Corophium volutator relative to experimental conditions, physical and chemical disturbances
Authors: Hellou Jocelyne , Cheeseman Kerri , Jouvenelle Marie-Laure , Robertson Sarah
Published: November 2005

The preference/avoidance behavioral response of a widely used amphipod in toxicity tests, Corophium volutator, was investigated in relation to the presence of anthropogenic physical or chemical materials in sediments. Exposure conditions, including the density of amphipods, the depth of sediments, amount of overlying water, and exposure time, were examined for their influence on amphipods' preference for field sediments and avoidance of coarse sand. It was shown that these variables did not affect the response; thus, conditions similar to published standard toxicity tests were chosen. A gradient of sediments spiked with potential habitat disturbances that can be found on a beach or in contaminated sediments, such as those in harbors, were tested. These substances included sand, seaweed, burned wood, coal, crankcase oil, and diesel oil. To enhance the interpretation of results and decrease the variability observed when tests were conducted at different times over the summer, exposures were performed over a gradient of spike material in reference sediments. We conclude that physical obstacles added to reference sediments lead to less correlation with the behavioral response than observed with chemical interferences. Amphipods' behavior ranked harbor sediments similarly to previous studies concerning the health of intertidal mussels collected in proximity to the sediments sites. For five sites, preference of reference sediments was observed until the level of polycyclic aromatic hydrocarbons in diluted harbor sediments reached the Canadian Council of Ministers of the Environment sediment quality guidelines.
Polychlorinated biphenyl 126 affects expression of genes involved in stress-immune interaction in primary cultures of rainbow trout anterior kidney cells
Authors: Quabius Elgar Susanne , Krupp Guido , Secombes Christopher J.
Published: November 2005

Stress and immune function are linked in all vertebrates, including teleost fish. Polychlorinated biphenyls (PCBs) are immunotoxic and impair the ability of fish to respond to additional stressors. In this study, we investigated the effects of PCB126 on stress and immune function and the interaction of these systems in fish using primary cultures of rainbow trout anterior kidney cells as a model. Gene expression levels of cytochrome P4501A (CYP1A), interleukin-1β (IL-1β), and glucocorticoid receptor (GR) were measured by real-time quantitative polymerase chain reaction. These genes play important roles in detoxification and immune and stress homeostasis, respectively. Incubation with PCB126 led to increased IL-1β expression between 30 min and 2 h of exposure, with expression back to basal levels after 6 h. Lipopolysaccharide (LPS) incubation evoked normal IL-1β responses after 2 and 24 h PCB incubation. Gene expression levels of GR and CYP1A increased in a time- and dose-dependent manner, reaching a plateau after 12 h of incubation. Preincubation with cortisol resulted in decreased IL-1β expression, increased expression of CYP1A and GR and was accompanied by an abolished PCB responsiveness after more than 4 h of cortisol incubation. We conclude that PCB126 exposure is not “stressful,” as increased cortisol levels would result in depressed IL-1β expression. Incubation with PCB126 evokes a transient stimulation rather than permanent damage of the immune system, as LPS stimulation resulted in increased IL-1β expression after PCB incubation. Prolonged cortisol preincubation, resembling a chronic stress paradigm, negatively affects the immune responsiveness of the cells as well as their capacity for toxicant metabolization.
Effects of storage aging on the cure kinetics of bismaleimide prepregs
Authors: Frigione M. , Kenny J. M.
Published: November 2005

The effects of room temperature aging on the subsequent polymerization kinetics of a bismaleimide (BMI) matrix prepreg, for high performance composites, have been characterized by different time and storage conditions. The study has focused on the stability of BMI matrix carbon fiber prepregs, when exposed to controlled environmental conditions before being used in composite manufacturing. The effects of aging on glass transition temperature, reactivity, and processability have been investigated by calorimetry through dynamic, isothermal, and cure‐simulating tests. A theoretical kinetic model for epoxy matrix prepregs, developed in previous studies, has been applied to the polymerization of both aged and unaged BMI matrix. The model is able to satisfactorily describe the effect of processing variables such as temperature and degree of reaction during the curing of the composite under different conditions (curing temperature and heating rate). The effects of diffusion‐controlled phenomena on the reaction kinetics, associated with changes in glass transition temperature as a function of the degree of polymerization and cross‐linking, have been taken into account in the formulation of an nth‐order kinetic model. © 2005 Wiley Periodicals, Inc. Adv Polym Techn 24: 253–265, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.20048
Preparation and properties of room temperature self‐crosslinking poly(MMA‐co‐BA‐co‐St‐co‐VTES) latex film
Authors: Guo Tian Ying , Xi Chen , Hao Guang Jie , Song Mou Dao , Zhang Bang Hua
Published: November 2005

Self‐crosslinking poly(methyl methacrylate‐co‐n‐butyl acrylate‐co‐styrene‐co‐vinyltriethoxysilane) latex particles were prepared by seed emulsion polymerization. The presence of SiOSi in the prepared copolymer latex particle was confirmed by FT‐IR. The crosslinking degree of the polymer latex particle was investigated by using tetrahydrofuran to swell the dried copolymer films with different vinyltriethoxysilane contents. The thermal properties of the solid films were investigated by using DSC and TGA. In addition, the mechanical properties and water resistances of the different copolymer films were also investigated in detail. It was found that the mechanical properties of the copolymer film could be enhanced by introducing vinyltriethoxysilane, and the water resistance of the copolymer film could be improved at certain vinyltriethoxysilane contents. © 2005 Wiley Periodicals, Inc. Adv Polym Techn 24: 288–295, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.20051
Pay more and resolve cases? The value issue in court mediation
Authors: Kichaven Jeff
Published: November 2005

Jeff Kichaven, of Los Angeles, looks at how market forces and mediation processes affect the results in court programs, and how they support a competitive compensation structure for court mediators, rather than volunteer programs.
Looking back, and ahead: The Panama Convention after 30 years
Authors: Erickson Helena Tavares , Gupta Preeti , Sutter Philip
Published: November 2005

The pullout feature returns with history and future practice surrounding the Panama Convention. Helena Tavares Erickson, Preeti Gupta and Philip Sutter, of New York, provide tips for corporate counsel facing actions under the controlling arbitration treaty for U.S. companies doing business in Latin America.
Organizational learning capacity and attitude toward complex technological innovations: An empirical study
Authors: Teo Hock‐Hai , Wang Xinwei , Wei Kwok‐Kee , Sia Choon‐Ling , Lee Matthew K. O.
Published: November 2005

Recent studies have found organizational learning capacity to be a key factor in influencing organizational assimilation and exploitation of knowledge‐intensive innovations. Despite its increasing importance, the impact of organizational learning capacity on technology assimilation is not well understood. Distilling from extant works on organizational learning and technology assimilation, this study identifies four components of organizational learning capacity, namely, systems orientation, organizational climate for learning orientation, knowledge acquisition and utilization orientation, and information sharing and dissemination orientation. The authors subject these components to structural equation modeling analyses to better understand their structure and dimensionality. The analyses strongly support the proposed four major dimensions underlying organizational learning capacity. Organizational learning capacity, as a higher‐order factor, has a significant impact on attitude towards organizational adoption of knowledge‐intensive innovations. Implications for practice and research are discussed.
Psychophysiological tests and provocation of subjects with mobile phone related symptoms
Authors: Wilén Jonna , Johansson Amanda , Kalezic Nebojsa , Lyskov Eugene , Sandström Monica
Published: November 2005

The aim of the present study was to investigate the effect of exposure to a mobile phone‐like radiofrequency (RF) electromagnetic field on persons experiencing subjective symptoms when using mobile phones (MP). Twenty subjects with MP‐related symptoms were recruited and matched with 20 controls without MP‐related symptoms. Each subject participated in two experimental sessions, one with true exposure and one with sham exposure, in random order. In the true exposure condition, the test subjects were exposed for 30 min to an RF field generating a maximum SAR1g in the head of 1 W/kg through an indoor base station antenna attached to a 900 MHz GSM MP. The following physiological and cognitive parameters were measured during the experiment: heart rate and heart rate variability (HRV), respiration, local blood flow, electrodermal activity, critical flicker fusion threshold (CFFT), short‐term memory, and reaction time. No significant differences related to RF exposure conditions were detected. Also no differences in baseline data were found between subject groups, except for the reaction time, which was significantly longer among the cases than among the controls the first time the test was performed. This difference disappeared when the test was repeated. However, the cases differed significantly from the controls with respect to HRV as measured in the frequency domain. The cases displayed a shift in low/high frequency ratio towards a sympathetic dominance in the autonomous nervous system during the CFFT and memory tests, regardless of exposure condition. This might be interpreted as a sign of differences in the autonomous nervous system regulation between persons with MP related subjective symptoms and persons with no such symptoms. Bioelectromagnetics 27:204–214, 2006. © 2005 Wiley‐Liss, Inc.
Lack of direct DNA damage in human blood leukocytes and lymphocytes after in vitro exposure to high power microwave pulses
Authors: Chemeris N.K. , Gapeyev A.B. , Sirota N.P. , Gudkova O.Yu. , Tankanag A.V. , Konovalov I.V. , Buzoverya M.E. , Suvorov V.G. , Logunov V.A.
Published: November 2005

Currently, the potential genotoxicity of high power microwave pulses (HPMP) is not clear. Using the alkaline single cell gel electrophoresis assay, also known as the alkaline comet assay, we studied the effects of HPMP (8.8 GHz, 180 ns pulse width, peak power 65 kW, pulse repetition frequency 50 Hz) on DNA of human whole‐blood leukocytes and isolated lymphocytes. The cell suspensions were exposed to HPMP for 40 min in a rectangular waveguide. The average SAR calculated from the temperature kinetics was about 1.6 kW/kg (peak SAR was about 300 MW/kg). The steady‐state temperature rise in the 50 µl samples exposed to HPMP was 3.5 ± 0.1 °C. In independent experiments, we did not find any statistically significant DNA damage manifested immediately after in vitro HPMP exposure of human blood leukocytes or lymphocytes or after HPMP exposure of leukocytes subsequently incubated at 37 °C for 30 min. Our results indicate that HPMP under the given exposure conditions did not induce DNA strand breaks, alkali‐labile sites, and incomplete excision repair sites, which could be detected by the alkaline comet assay. Bioelectromagnetics 27:197–203, 2006. © 2005 Wiley‐Liss, Inc.
Bis(stannyl)phosphanyl‐Substituted Dichlorosilanes/Germanes — Potential Precursors for a Novel Strategy Toward P–Si/Ge Multiple Bonds?
Authors: Bender Marion , Niecke Edgar , Nieger Martin , Pietschnig Rudolf
Published: November 2005

A general synthetic route to bis(stannyl)phosphanyl‐substituted dichlorosilanes/germanes of the type R–SiCl2–P(SnMe3)2 and R–GeCl2–P(SnMe3)2 is reported. For R = Cp* (= 1,2,3,4,5‐pentamethylcyclopentadienyl) crystal structures for the corresponding silane and germane could be obtained. These compounds are the first structurally characterized bis(stannyl)phosphanyl‐substituted dichlorosilanes/germanes that due to their functionalities should be ideal precursors for the generation of unsaturated PSi and PGe units and possibly phosphasilynes and phosphagermynes. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Synthesis of Sugar Isocyanates and Their Application to the Formation of Ureido‐Linked Disaccharides
Authors: Ávalos Martín , Babiano Reyes , Cintas Pedro , Hursthouse Michael B. , Jiménez José L. , Light Mark E. , Palacios Juan C. , Pérez Esther M. S.
Published: November 2005

The present work describes a facile and practical route to carbohydrate‐based isocyanates, a reactive and appealing family of chiral heterocumulenes, wich can be easily converted into disaccharides and pseudodisaccharides interconnected by urea moieties. A full characterization of these substances by X‐ray diffraction analysis and spectroscopic methods reveals further insights into their structures and preferred conformation. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Capillary electrophoresis of proteins 2003–2005
Authors: Dolník Vladislav
Published: November 2005

This review article with 304 references describes recent developments in CE of proteins, and covers the two years since the previous review (Hutterer, K., Dolník, V., Electrophoresis 2003, 24, 3998–4012) through Spring 2005. It covers topics related to CE of proteins, including modeling of the electrophoretic migration of proteins, sample pretreatment, wall coatings, improving separation, various forms of detection, special electrophoretic techniques such as affinity CE, CIEF, and applications of CE to the analysis of proteins in real‐world samples including human body fluids, food and agricultural samples, protein pharmaceuticals, and recombinant protein preparations.
Analysis of explosives via microchip electrophoresis and conventional capillary electrophoresis: A review
Authors: Pumera Martin
Published: November 2005

The upsurge in terrorist activity has generated tremendous demand for innovative tools capable of detecting major industrial, military, and home‐made (improvised) explosives. Fast, sensitive, and reliable detection of explosives in the field is a very important issue in nowadays. CE, especially in its miniaturized format (lab‐on‐a‐chip), offers great possibilities to create portable, field deployable, rapidly responding, and potentially disposable devices, allowing security forces to make the important decisions regarding the safety of civilians. This article overviews the microchip and conventional capillary electrophoretic techniques for analysis of a wide variety of explosive compounds and mixtures.
Potential bias in generalized estimating equations linkage methods under incomplete information
Authors: Lebrec J. , Putter H. , van Houwelingen J.C.
Published: November 2005

The mean identity‐by‐descent (IBD) specification used in the Generalized Estimating Equations (GEE) methodology for linkage is only valid, strictly speaking, under the assumption of fully polymorphic markers. In practice, markers often provide only partial IBD information, which can potentially result in inconsistency of the locus location and gene effect estimates obtained by the GEE method. Using both simulations and theory, we identify some realistic conditions about marker information under which the validity of the GEE linkage methods may be arguable. Namely, researchers should not trust the GEE parameters' estimates and their associated confidence intervals in areas of the genome where IBD information is sparse or when this information changes abruptly. We show that properly standardized statistics based on IBD sharing provide a valid alternative. Genet. Epidemiol. 2006. © 2005 Wiley‐Liss Inc.
Nicotine prevents stress‐induced enhancement of long‐term depression in hippocampal area CA1: Electrophysiological and molecular studies
Authors: Aleisa A.M. , Alzoubi K.H. , Alkadhi K.A.
Published: November 2005

Nicotine treatment prevents chronic psychosocial stress‐induced impairment of hippocampus‐dependent spatial memory and long‐term potentiation (LTP). In this study, we investigated the effect of chronic nicotine treatment on stress‐induced enhancement of long‐term depression (LTD). After paired‐pulse stimulation, LTD was evoked in area CA1 of anesthetized control, stressed, nicotine‐treated, and nicotine‐treated stressed rats. In stressed rats, a significantly greater LTD magnitude was seen than in control rats. Stress also facilitated the induction of LTD. Nicotine treatment of stressed rats prevented stress‐induced enhancement and facilitation of LTD. For chronically stressed rats, we previously reported marked decreases in the basal levels of brain‐derived neurotrophic factor (BDNF), CaMKII, P‐CaMKII, and calmodulin as well as a significant increase in calcineurin basal levels. Herein, Western blot analysis conducted 1 hr after induction of LTD by paired‐pulse stimulation showed that the levels of calcineurin and P‐CaMKII were increased in the stressed group compared with the other groups and were normalized by chronic nicotine treatment. Additionally, after paired‐pulse stimulation, the levels of total CaMKII were increased in all groups with no change in the levels of BDNF and calmodulin. Therefore, the increase in the levels of calcineurin and P‐CaMKII during expression of LTD in area CA1 may explain the enhanced magnitude of LTD in chronically stressed rats. © 2005 Wiley‐Liss, Inc.
Multilayer Microcapsules as Anti‐Cancer Drug Delivery Vehicle: Deposition, Sustained Release, and in vitro Bioactivity
Authors: Liu Xingyu , Gao Changyou , Shen Jiacong , Möhwald Helmuth
Published: November 2005

Summary: A drug delivery system based on spontaneous deposition of soluble, low‐molecular‐weight therapeutic agents has been developed for the purpose of sustaining drug release. Layer‐by‐layer assembly of oppositely charged polyelectrolytes onto melamine formaldehyde (MF) colloidal particles, followed by removal of the cores at low pH has yielded intact hollow microcapsules having the ability to induce deposition of various water‐soluble substances. Dynamic observation by confocal laser scanning microscopy provided direct evidence of such deposition. Dependence of loading rate on molecular weight was investigated. Efficient loading of an anti‐cancer drug, daunorubicin (DNR), was confirmed by transmission electron microscopy (TEM). Its release was quantified by fluorometry. The results indicated that loading, and subsequent release, could be tuned by factors such as feeding concentrations, temperature, and salt concentrations. The intrinsic mechanism of loading and release was discussed taking into account the interaction between the drugs and the poly(styrene sulfonate)/MF complex existing in the hollow capsules. With culture of the HL‐60 cell line, a kind of human leukemia cell, the presence of DNR‐loaded capsules was seen to steadily decrease the cytoviability.

Fluorescence intensity averaged from inside the circles as a function of incubation time.

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Fluorescence intensity averaged from inside the circles as a function of incubation time.
Hydroxyapatite Reinforced Chitosan and Polyester Blends for Biomedical Applications
Authors: Correlo Vitor M. , Boesel Luciano F. , Bhattacharya Mrinal , Mano Joao F. , Neves Nuno M. , Reis Ruis L.
Published: November 2005

Summary: Hydroxyapatite, chitosan, and aliphatic polyester were compounded using a twin‐screw extruder. The polyesters include poly(ε‐caprolactone) (PCL), poly(lactic acid) , poly(butylene succinate) (PBS), and poly(butylene terephthalate adipate). The mass fraction of chitosan ranged from 17.5 to 45%, while that of HA ranged from 10 to 30%. These blends were injection molded and evaluated for thermal, morphological, and mechanical properties. The addition of hydroxyapatite decreased the crystallinity in chitosan/PBS blends, while in blends containing chitosan/PCL, the crystallinity increased. Addition of hydroxyapatite significantly decreased the tensile strength and elongation of polyester/hydroxyapatite composites as well as chitosan/polyester/hydroxyapatite composites with elongations undergoing decreases over an order of magnitude. The tensile strength of the composite was dictated by the adhesion of HA to the chitosan/polyester matrix. The tensile strength of composites containing hydroxyapatite could be predicted using the Nicolai and Narkis equation for weak filler adhesion (K ≈ 1.21). Tensile‐fractured and cryogenically‐fractured surface indicates extensive debonding of hydroxyapatite crystals from the matrix, indicating weak adhesion. The adhesion of hydroxyapatite was higher for pure polyester than those containing chitosan and polyester. The modulus of the composites registered modest increase. The two main diffraction peaks observed using WAXS are unaffected by the amount of chitosan or hydroxyapatite.

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Overexpression of ErbB2 and ErbB3 receptors in Schwann cells of patients with Charcot–Marie–Tooth disease type 1A
Authors: Massa Roberto , Palumbo Camilla , Cavallaro Tiziana , Panico Maria Beatrice , Bei Roberto , Terracciano Chiara , Rizzuto Nicolò , Bernardi Giorgio , Modesti Andrea
Published: November 2005

Axon‐derived neuregulins (NRGs) are a family of growth factors whose binding to ErbB tyrosine kinase receptors promotes the maturation, proliferation and survival of Schwann cells (SCs). Correct NRG/ErbB signaling is essential for the homeostasis of axonal–glial complexes and seems to play a role in peripheral nerve repair. The potential involvement of ErbB receptors in human peripheral neuropathies has not been clarified. Therefore, we assessed the immunoreactivity for EGFR (ErbB1), ErbB2, and ErbB3 in nerve biopsies from patients with different forms of Charcot–Marie–Tooth disease, type 1, (CMT1), as compared to others with inflammatory neuropathies and controls. The most notable changes consisted in the overexpression of ErbB2 and ErbB3 by SCs of nerves from CMT1A patients. These findings are consistent with an impairment of SC differentiation and expand the molecular phenotype of CMT1A. The upregulation of these receptors may play a role in the inhibition of myelination or in the promotion of recurrent demyelination and axonal damage. Muscle Nerve, 2006
Coactivation of the elbow antagonist muscles is not affected by the speed of movement in isokinetic exercise
Authors: Bazzucchi Ilenia , Sbriccoli Paola , Marzattinocci Giulia , Felici Francesco
Published: November 2005

Since muscle coactivation increases the stiffness and stability of a joint, greater coactivation is likely during faster than slower movements. Very few studies, though, have been conducted to verify this hypothesis. Moreover, a large number of studies have examined coactivation of muscles surrounding the knee joint whereas there are few reports on the elbow joint. The aim of this study was therefore to compare the antagonist activation of the elbow flexors and extensors during isokinetic concentric exercises and to investigate the influence of angular velocity on their activation. Twelve men participated in the study. The surface electromyographic signals (sEMG) were recorded from the biceps brachii (BB) and triceps brachii (TB) muscles during three maximal voluntary isometric contractions (MVC) of elbow flexors and extensors and a set of three maximal elbow flexions and extensions each at 15°, 30°, 60°, 120°, 180°, and 240°.s−1. Normalized root mean square (RMS) of sEMG was calculated during the isokinetic phase of movement as an index of sEMG amplitude. During elbow flexion, the antagonist activation of BB averaged 16.2% lower than TB, and this difference was statistically significant at all angular velocities. The normalized RMS values ranged from 26.0% ± 19.0 at MVC to 37.8% ± 13.9 at 240°.s−1 for antagonist TB activation, and from 5.7% ± 5.2 at MVC to 18.9% ± 8.6 at 240°.s−1 for antagonist BB activation. No influence of angular velocity on agonist and antagonist activity was found. Moreover, flexion and extension torques were both strongly affected by the amount of antagonist activation. The functional specialization of the two muscle groups could be responsible for the different levels of antagonist activation. The frequent use of BB, which is not assisted by gravity during daily activities, could lead to reduced coactivation due to a better functioning of the control system based upon reciprocal innervation. These findings may have significant implications in the design of rehabilitation programs directed to the elbow joint. Muscle Nerve, 2006
The electromyographic signal as a presymptomatic indicator of organophosphates in the body
Authors: De Luca Carlo J. , Buccafusco Jerry J. , Roy Serge H. , De Luca Gianluca , Nawab S. Hamid
Published: November 2005

Organophosphate (OP) compounds are present in household and agricultural pesticides as well as in nerve agents. The toxic effects of these chemicals result from their anticholinesterase activity, which disrupts nerve junctions and parasympathetic effector sites, leading to a variety of symptoms and possible death. When the anticholinesterase agents in OP compounds reach the neuromuscular junction, they cause a disruption in the firing of muscle fiber action potentials. This effect has the potential of altering the time course of the electromyographic (EMG) signal detected by surface electrodes. We investigated the association between OP compound dose, surface EMG changes, and overt signs of OP toxicity. Daily doses of 10–15 μg/kg of diisopropylfluorophosphate (DFP) were injected into the calf muscle of four rhesus monkeys while surface EMG signals were recorded from two thigh muscles bilaterally. With increasing number of doses, the EMG signal presented an increasing number of time gaps. The presence of the gaps was evident prior to any overt symptoms of cholinesterase toxicity. These findings can lead to the development of noninvasive technology for indicating the presence of OP compounds in muscle tissue prior to clinical abnormalities. Muscle Nerve, 2006
Which patients need referral for anal sphincter electromyography?
Authors: Podnar Simon
Published: November 2005

Needle electromyography (EMG) of lower sacral myotomes is useful in certain patients with urinary, bowel, or sexual dysfunction. The aim of the study was to identify the clinical profile of patients who require such testing. Medical records were retrospectively reviewed, and findings evaluated using bivariate and multivariate statistics. A neuropathic condition affecting the lower sacral segments was diagnosed by quantitative concentric needle EMG of the external anal sphincter (EAS) muscle. Neuropathic changes in the EAS were found in 85 (44%) of 193 patients studied. On ordinal logistic regression analysis, bladder‐emptying difficulties and perineal sensory loss were significantly related to the presence of a neuropathic EMG. No guidelines for referral for anal sphincter EMG could be defined that would include all patients with neuropathic abnormalities in the lower sacral segments. However, patients with bladder‐emptying difficulties and perineal sensory loss seem to be the most suitable candidates for testing. Muscle Nerve, 2006