bluuebunny/crossref_metadata_2025 huggingface dataset:
Avaliação do uso do Hylano GF-20 no pós-operatório de artroscopia de joelho por artrose
Authors: Rejaili Wilson Abou , Chueire Alceu Gomes , Cordeiro José Antonio , Petean Flavio Calil , Carvalho Filho Guaracy de
Published: May 2005

O presente estudo avaliou os benefícios do uso do Hylano GF-20 no pós-operatório de artroscopias do joelho para lavagem e desbridamento por artrose.Foram estudados 20 pacientes submetidos à artroscopia em 20 joelhos que apresentavam artrose até grau 3 da classificação com sintomas de dor e bloqueio no referido joelho e não obtiveram melhora ao tratamento conservador, sendo então realizada lavagem associada a desbridamento leve condral e meniscal de acordo com a necessidade de cada caso.Os pacientes foram divididos em 2 grupos sendo que em um dos grupos foi feita apenas a artroscopia e noutro grupo artroscopia associada ao uso de 3 infiltrações realizadas semanalmente de Hylano GF-20.Os pacientes foram avaliados nas variáveis dor em repouso noturna, dor durante movimento com sobrecarga de 10% do peso corporal, dor durante o movimento mais doloroso do joelho afetado com escala visual e a variável quantidade diária de diclofenaco potássico ingerida para alívio da dor no joelho afetado. Os resultados estatísticos mostraram melhora significativa em todas as variáveis estudadas nos pacientes do grupo submetidos ao uso de infiltrações com o Hylano GF-20 no pós-operatório de artroscopias do joelho por artrose no período de 6 meses.
Efeito de ondas de choque na placa de crescimento de coelhos
Authors: Giusti Guilherme , Penteado Fernando Travaglini , Santos João Baptista Gomes dos , Alves Maria Tereza de Seixas , Faloppa Flávio
Published: May 2005

OBJETIVO: Avaliar os efeitos da aplicação de ondas de choque na placa de crescimento de coelhos, variando a energia e o número de ondas aplicadas. MATERIAL E MÉTODOS: Foram estudados 30 coelhos com idade de cinco semanas divididos em seis grupos. O aparelho gerador de ondas de choque foi o OSSATRON (HMT). Os animais foram submetidos a aplicações na placa de crescimento proximal da tíbia esquerda, variando a intensidade (14, 21,28kV) e o número de ondas (1000 e 4000). A tíbia direita foi usada como controle. Os animais foram sacrificados após seis semanas e sua avaliação foi feita por meio da mensuração do comprimento das tíbias e pela análise microscópica da placa de crescimento. Os resultados de mensuração da área da placa e do comprimento das tíbias foram comparados com o grupo controle e entre os grupos, utilizando-se estudos estatísticos. RESULTADOS: Neste estudo não ocorreram alterações estatisticamente significantes nas medidas da área da placa ou do comprimento da tíbia após a aplicação de ondas de choque em nenhum dos grupos. Foi observada tendência de ocorrer uma diferença de crescimento das tíbias entre os grupos submetidos a 1.000 impulsos e os grupos submetidos a 4.000 impulsos, mas esta diferença não foi considerada significante. Foi observada também a formação de hematoma no local da aplicação nos grupos que receberam ondas com maior energia, evoluindo com regressão espontânea sem necessidade de cuidados especiais. CONCLUSÕES: A aplicação de ondas de choque na região proximal da tíbia de coelhos imaturos, nas formas descritas, não teve nenhum efeito na placa de crescimento, de acordo com os métodos de avaliação usados neste estudo.
Fixação externa em fraturas de fêmur em crianças
Authors: Carvalho Filho Guaracy , Chueire Alceu Gomes , Ignácio Helencar , Amaral Alexandre Roldão Cardoso do , Catelan Giampaulo Marcelo , Castro Júnior Marco Aurélio Taucci de
Published: May 2005

Em um estudo prospectivo, avaliamos os resultados da fixação externa em fraturas femorais em crianças. No período de 1997 a 2000, 24 crianças com 26 fraturas diafisárias de fêmur (23 fraturas fechadas e três expostas) foram tratadas com fixador externo. A média de idade dos pacientes foi de oito anos e oito meses (variando de seis a 13 anos). Todas as fraturas foram seguidas até seis meses após a consolidação, que ocorreu em 100% dos casos, quando foi retirado o fixador externo com uma média de 87 dias (variando de 63 a 135 dias). A infecção através do trajeto dos pinos foi comum, mas nenhum paciente desenvolveu osteomielite. A principal complicação foi a refratura (17%), que necessitou de novo procedimento com o fixador.
Estudo radiográfico das alterações da coluna cervical na artrite reumatóide e sua associação com sinais e sintomas da doença
Authors: Souza Cesar P. , Defino Helton L.A.
Published: May 2005

As alterações radiográficas da coluna cervical de 81 pacientes em tratamento ambulatorial de artrite reumatóide foram estudadas e correlacionadas com dor a cervical e os sinais neurológicos relacionados com a compressão das estruturas nervosas contidas no canal vertebral. A correlação das alterações radiográficas com a classificação em graus e em estágios da doença preconizados pela ARA (American Rheumatism Association) e classificação da capacidade funcional de Steinbroker foi também realizada. A avaliação radiográfica foi realizada por meio de radiografias em AP, perfil e dinâmicas da coluna cervical. As alterações radiográficas (migração superior do processo odontóide, instabilidade atlanto-axial, instabilidade sub-axial ou erosão do processo odontóide) foram observada em 65 (80,2%) dos pacientes. Foi observado correlação estatisticamente significativa entre a capacidade funcional dos pacientes (classificação de Steibroker) e estágios da doença (ARA ) com as alterações radiográficas da coluna cervical dos pacientes. A presença de alterações radiográficas da coluna cervical dos pacientes com artrite reumatóide não apresentou correlação estatisticamente significativa com a dor ou sinais de compressão nervosa.
Short-term lab exposures of immature rainbow trout (Oncorhynchus mykiss) to sulfite and kraft pulp-mill effluents: Effects on oxidative stress and circulating sex steroids
Authors: Oakes Ken D. , Tremblay Louis A. , Kraak Glen J. Van Der
Published: May 2005

This study investigates the temporal onset of reactive oxygen species (ROS) damage and changes in circulating sex steroids in immature rainbow trout exposed over 21 d to two pulp-mill effluents. Exposure to effluent from a bleached sulfite mill produced increases in 2-thiobarbituric acid reactive substances (TBARS), ethoxyresorufin O-deethylase (EROD) activity, hepatic free iron, and significant depressions in hepatic ascorbic acid. Impairments in pregnenolone production relative to cholesterol availability suggest an effect of sulfite-mill effluent early in the steroidogenic pathway. Induction of vitellogenin in immature fish exposed to effluent from this mill, relative to waterborne 17 β-estradiol treatments, indicated sulfite-mill effluent contained constituents capable of binding the estrogen receptor. Exposure to a kraft-mill effluent also elevated hepatic TBARS, tissue normalized fatty acyl-coenzyme A oxidase (FAO) activity, and hepatic free iron while producing commensurate declines in hepatic ascorbic acid. Plasma testosterone, 11-ketotestosterone, and 17 β-estradiol were elevated with kraft-mill effluent exposure, but no changes in vitellogenin induction were observed. In summary, effluent from bleached sulfite and bleached kraft mills yielded similar oxidative stress responses, but marked differences were observed in the endocrine-disrupting potential of each effluent.
Application of the conductor-like screening model for real solvents for prediction of the aqueous solubility of chlorobenzenes depending on temperature and salinity
Authors: Oleszek-Kudlak Sylwia , Grabda Mariusz , Shibata Etsuro , Eckert Frank , Nakamura Takashi
Published: May 2005

The conductor-like screening model for real solvents (COSMO-RS) is applied to the prediction of the aqueous solubility of chlorobenzenes (CBZs) in a liquid-liquid and liquid-solid equilibrium. The solubilities of CBZs at temperatures ranging from 5 to 60°C are reported, and the enthalpies of solution are derived from van't Hoff plots. The salting effect of 12 chlorobenzenes is determined for sodium, potassium, and calcium solutions at concentrations ranging from 0.01 to 3.5 mol/L. A new experimental aqueous solubility value is given for the isotopic labeled 1,2,4-trichlorobenzene determined at 25°C by the generator column procedure. The COSMO-RS method presented in this study can be useful to estimate the magnitude of the salt effect and temperature influence on the behavior of any chlorobezene under environmental conditions.
Genetically determined resistance to lethal levels of copper by Daphnia longispina: Association with sublethal response and multiple/coresistance
Authors: Lopes Isabel , Baird Donald J. , Ribeiro Rui
Published: May 2005

The development of resistance to toxicants has been reported for a wide range of organisms. Two questions were addressed in the present study: Are genetically determined resistance responses at lethal levels (min to h) of copper associated with responses at extreme lethal (h to d) and sublethal levels and does genetically determined resistance to lethal levels of copper confer resistance to lethal levels of other chemicals? Twelve cloned lineages of Daphnia longispina, differing in their resistance to copper, were exposed to sublethal concentrations of copper and to lethal concentrations of copper, zinc, cadmium, hydrogen ions, and a pyrethroid insecticide (deltamethrin). Three kinds of toxicity assays were carried out: Survival time (death occurs in min to h; only for metals and hydrogen ions), cumulative mortality (death occurs in h to d; for all tested chemicals), and feeding depression assays (only for copper). A correlation between different levels of toxicity was observed only for extreme and moderate lethal responses to copper, and no correlation was found between lethal and sublethal levels of copper. Multiple resistance to lethal levels of toxicants was observed only for the pair copper/zinc.
Arsenic speciation in terrestrial birds from Yellowknife, Northwest Territories, Canada: The unexpected finding of arsenobetaine
Authors: Koch Iris , Mace Jessica V. , Reimer Kenneth J.
Published: May 2005

The surrounding area of Yellowknife, Northwest Territories, Canada, is known for naturally and anthropogenically elevated concentrations of arsenic. Five bird species (gray jay [Perisoreus canadensis], American tree sparrow [Spizella arborea], dark-eyed junco [Junco hyemalis], yellow-rumped warbler [Dendroica coronata], and spruce grouse [Dendragapus canadensis]) were collected from this area. Their tissues were analyzed for total arsenic and for arsenic species, allowing us to report, to our knowledge for the first time, the arsenic characterization in terrestrial birds. Total arsenic concentrations were determined in the terrestrial birds by inductively coupled plasma-optical emission spectrometry, whereas arsenic speciation analysis was performed using high-performance liquid chromatography-inductively coupled plasma-mass spectrometry. Total arsenic concentrations were substantially higher in the terrestrial bird species studied from Yellowknife compared with those reported previously in the literature. The primary arsenic species detected in two of the bird species studied was arsenobetaine. Normally, arsenobetaine is not formed or retained by terrestrial animals. Thus, the birds in the present study were thought to be highly adapted compared with other terrestrial animals, because they were able to form and/or retain this relatively nontoxic arsenic compound. This adaptation is thought to be a consequence of the elevated concentrations of arsenic in the Yellowknife area.
Modeling the effects of chronic toxicity on fish populations: The influence of life-history strategies
Authors: Spromberg Julann A. , Birge Wesley J.
Published: May 2005

Five life-history scenarios were composed to simulate fish population adaptations for survival under various environmental conditions. The scenarios encompassed differences in stage-specific survival, fecundity and hatch success, number of spawning events, and life-span effect response to chronic toxic impacts. The strategies represent a good survivor/generalist (GS), a species exhibiting high young-of-the-year survival, a species exhibiting high adult survival, a species with no parental care or guarding behavior, and an anadromous salmonid strategy. Although the modeled scenarios were similar in population growth rate and imposed toxic effects, differences concerning the influence of various traits were found. Scenarios characterized by a short life span, short time to reproductive maturity, moderate to high survival to reproductive maturity, large number of spawning events, and parental guarding behaviors experienced less perturbation from the imposed chronic stresses. The GS scenario, modeled after the round goby (Neogobius melanostomus), exemplified these characteristics. Scenarios exhibiting little difference between reproductive effort for younger and older adults recovered quickly from stressors on fecundity and adult survival rates. Greater population decline in response to commensurate impacts was seen for life-history strategies with long life span, no parental guarding behaviors, semelparity and annual iteroparity, high adult survival rates, and moderate to low fecundity.
A critical review of the biogeochemistry and ecotoxicology of selenium in lotic and lentic environments
Authors: Simmons Denina B.D. , Wallschläger Dirk
Published: May 2005

Anthropogenic activities resulting in elevated selenium (Se) levels in aquatic ecosystems can result in teratogenic and reproductive effects in fish and waterfowl. However, relationships between observed effects and exposure concentrations or body burdens are ambiguous. Therefore, it is critical to identify factors that affect Se ecotoxicity before defining adequate protective environmental regulations. One important political debate questions if Se ecotoxicity differs between standing (lentic) and flowing (lotic) waters and, if so, how this should be incorporated into the definition of protective criteria. In the present review, we compile and discuss the scarce literature regarding Se ecotoxicity in lotic systems, and we compare it to the substantial body of evidence for lentic systems. General differences between lentic and lotic systems with respect to ecology, hydrology, and biogeochemistry are identified and related to Se ecotoxicity. The limited knowledge regarding Se speciation in the biomagnification process is reviewed and put in context. Fundamental considerations suggest that Se ecotoxicity in lotic systems should be reduced compared to lentic systems, but we conclude that this statement is not substantiated by the existing data. Additionally, we identify critical gaps of knowledge that must be resolved in future studies before the argument can be decided conclusively.
Evaluating the biodegradability of sulfamethazine, sulfamethoxazole, sulfathiazole, and trimethoprim at different stages of sewage treatment
Authors: Pérez Sandra , Eichhorn Peter , Aga Diana S.
Published: May 2005

The aerobic biodegradability of four antimicrobials (sulfamethazine, sulfamethoxazole, sulfathiazole, and trimethoprim) was investigated in sewage collected at four treatment stages (primary treatment, activated sludge treatment, aerobic nitrification process, and after disinfection of treated sewage) of a municipal sewage treatment plant. The biodegradability tests were conducted in aerated batch reactors by spiking the sewage with 20 μg/L of each of the test substance. Concentration profiles of the assayed compounds were monitored during a 54-d period using liquid chromatography/electrospray ionization/mass spectrometry. Substantial differences in the degradation curves were observed between trimethoprim and the three sulfonamides. The behavior of the latter was characterized by a general biodegradability in the primary and secondary treatment. The highest degradation rates were obtained in the sewage from the activated sludge treatment, where no adaptation phase was observed. On the other hand, the onset of biodegradation in the sewage from the primary treatment was preceded by a lag phase ranging from 10 to 15 d. In contrast, trimethoprim displayed high resistance to microbial degradation in the sewage from the primary treatment and the activated sludge treatment. However, primary degradation of this compound was completed within only 3 d in the sewage from the nitrification process.
Zinc toxicity to the mottled sculpin (Cottus bairdt) in high-hardness water
Authors: Brinkman Stephen , Woodling John
Published: May 2005

The median 96-h lethal zinc concentration (LC50) was 439 μg Zn/L (hardness of 154 mg/L as CaCO3) for feral mottled sculpin (Cottus bairdi), decreasing to a median incipient lethal level of 266 μg Zn/L after 13 d. The 30-d chronic value was 255 μg Zn/L. The acute toxicity-hardness (ln-ln) slope of 1.022 exceeded that of the current U.S. Environmental Protection Agency zinc criteria. The mottled sculpin is the second most sensitive fish species for which toxicity data are available.
Kinetics of the reduction of chromium(VI) by vitamin C
Authors: Xu Xiang-Rong , Li Hua-Bin , Gu Ji-Dong , Li Xiao-Yan
Published: May 2005

The kinetics of the reduction of Cr(VI) to Cr(III) by vitamin C was studied using potassium dichromate solution as the model pollutant. Effects of the concentration of vitamin C, pH, temperature, and irradiation on the reduction of Cr(VI) were examined. The kinetics of Cr(VI) reduction by vitamin C can be described as -d[Cr(VI)]/dt = 0.0156 (μM s−1).[Cr(VI)][vitamin C] (pH 5), where dt is the differential function (d) of time (t). The activation entropy (ΔS‡) and enthalpy (ΔH‡) are 42.4 kJ mol−1 and -71.0 J mol−1 K−1, respectively, and the activation energy at 298 K is 63.5 kJ mol−1. The advantages of vitamin C as a reductant are as follows: It is an important biological reductant in humans and animals, and it is not toxic. Toxic Cr(VI) can be reduced by vitamin C not only in acidic conditions but also in alkaline solutions (pH 9); furthermore, the reduction was shown to occur both under the irradiation and in the dark. The present results suggest that vitamin C could be used effectively in the remediation of Cr(VI)-contaminated soil and groundwater in a wide range of pH, with or without sunlight.
Dermal bioavailability of benzo[a]pyrene on lampblack: Implications for risk assessment
Authors: Stroo Hans F. , Roy Timothy A. , Liban Cris B. , Kreitinger Joseph P.
Published: May 2005

Lampblack is the principal source of contamination in soils at manufactured gas plant (MGP) sites where oil was used as the feedstock. Risks and cleanup criteria at these sites are determined primarily by the total carcinogenic polynuclear aromatic hydrocarbon (PAH) content, particularly the concentration of benzo[a]pyrene (BaP). Dermal contact with soils at oil-gas MGP sites is a significant component of the overall risks. Seven samples were collected from oil-gas MGP sites and the steady-state dermal fluxes were measured over 96 h in vitro. The standard dermal bioassay technique (in which 3H-BaP is added to the soil matrix) was modified to allow direct measurement of the dermal absorption of the native BaP in the samples. The experimentally derived dermal absorption factors for BaP were 14 to 107 times lower than the default assumption of 15% over 24 h (55-fold lower on average). The dermal fluxes were correlated positively to the total BaP and total carbon concentrations. The measured dermal absorption factors were compared to the default risk-assessment calculations for all seven samples. The calculated excess cancer risk was reduced as a result of using the measured absorption factors by 97% on average (with reductions ranging from 93 to 99%). This work indicates the risks at oil-gas MGP sites currently are overestimated by one to two orders of magnitude, and provides a protocol for the testing and data analysis needed to generate site-specific cleanup levels.
Abiotic dealkylation and hydrolysis of atrazine by birnessite
Authors: Shin Jin Y. , Cheney Marcos A.
Published: May 2005

Atrazine (2-chloro-4-ethylamino-6-isopropylamino-s-triazine) and its degradation products are important contaminants of world water systems and have effects on aquatic life. These effects are modulated by the degradation of atrazine, which depends, in part, on its reactivity with soil minerals. We have studied the degradation reaction of atrazine on synthetic birnessite (δ-MnO2) in the aqueous phase using a batch reactor and a developed high-performance liquid chromatography method. The reaction was studied in the absence of light at 25°C and between pH 2.3 to pH 8.3. The reaction rates increased with decreasing pH and increasing 5-MnO2 loading, and they did not follow simple first-order kinetics. The major products are hydroxylated and mono- and didealkylatrazine. Ammeline and cyanuric acid also were detected. The half-life (t1/2) for the degradation of atrazine was approximately 16.8 d and independent of oxygen. Manganese(II) evolution was a minor product. The mechanism of dealkylation involved proton transfer to Mn(IV)-stabilized oxo and imido bonds, with no net oxidation and reduction. Oxidation was a secondary reaction. The proposed abiotic pathway for the transformation of atrazine on δ-MnO2 was identical to the reported biotic pathway. Thus, δ-MnO2, a common soil component, facilitated the efficient N-dealkylation and hydrolysis of the herbicide atrazine at 25°C, possibly via a nonoxidative mechanisms. The N-dealkylation has been attributed strictly to a biological process in soils.
Confirmation of cause-effect relationships using effect-directed analysis for complex environmental samples
Authors: Grote Matthias , Brack Werner , Walter Helge A. , Altenburger Rolf
Published: May 2005

The establishment of causal links between chemical contamination and observed ecotoxic effects of environmental samples is a major challenge in ecotoxicology. Effect-directed analysis is an approach combining fractionation with toxicity testing before chemical nontarget analysis to separate and subsequently identify toxic compounds in environmental samples. A final confirmation step in this procedure evaluates how much of the observed toxicity in the environmental sample can be attributed to the mixture of identified toxicants. The aim of the present study is to advance the methodology for the confirmation of mixtures in effect-directed analysis by using tools for the assessment of mixture toxicity accounting for unknown modes of action and heterogeneity of concentration-response curves. For this purpose, toxicants were identified in sediment extracts from two different sites. All identified compounds were tested both individually as pure compounds and in mixtures at ratios equal to those found in the sediment extracts. The observed extract toxicity was then compared with the expected combined effects calculated according to the models of concentration addition and independent action as well as with the observed toxicity of the synthetic mixture. Drawbacks of the established approach using toxic unit summation are demonstrated, and the Index of Confirmation Quality, an easy-to-read representation that allows a quantitative measure of confirmation over a range of different effect levels, is introduced.
Joint toxicity of sodium arsenate and sodium perchlorate to zebrafish Danio rerio larvae
Authors: Liu Fujun , Kendall Ronald J. , Theodorakis Christopher W.
Published: May 2005

Joint toxicity of arsenate and perchlorate was tested in larvae of Danio rerio. Results indicated that the 96-h median lethal concentrations of sodium arsenate and sodium perchlorate were 258.8 and 1,401.2 mg/L, respectively, and that arsenate and perchlorate generally showed a concentration-additive effect.
Modeling impact of parathion and its metabolite paraoxon on the nematode Caenorhabditis etegans in soil
Authors: Saffih-Hdadi Kawtar , Bruckler Laurent , Amichot Marcel , Belzunces Luc
Published: May 2005

Parathion is an insecticide of a group of highly toxic organophosphorous compounds. In vivo, it is activated to the toxic metabolite paraoxon. Laboratory experiments have shown that a single relationship between the variable (concentration × time of application) and the percentage of paralyzed nematodes is relevant. Aqueous (0.01 M CaCl2) extracts from soil that had received a dose of parathion as used in practice during an incubation experiment had no effect on nematodes, because sorption and biodegradation of the pesticide decreased the pesticide concentration in the soluble phase. To predict the toxicological effects of parathion and paraoxon on nematodes under various soil conditions during a simulation period of 20 d, we used a model predicting the concentrations of parathion and paraoxon over time in the soil liquid phase. In this model, sorption and biodegradation of both parathion and paraoxon were taken into account, and the results indicated that sorption effects were dominant and determined the differential toxicological risks between soils. Variable effects were predicted for short times (typically <5 d), and critical toxicological conditions were predicted for longer duration (typically > 10–15 d), in all cases.
Influence of larval period on responses of overwintering green frog (Rana clamitans) larvae exposed to contaminated sediments
Authors: Snodgrass Joel W. , Hopkins William A. , Jackson Brian P. , Baionno Jennifer A. , Broughton Jeffroy
Published: May 2005

Pond-breeding amphibians exhibit large intra- and interspecific differences in the duration of the aquatic larval phase. In contaminated aquatic environments, a prolonged larval phase means prolonged exposure to pollutants and, potentially, more severe toxic effects. In the laboratory, we tested this hypothesis by exposing green frog larvae (Rana clamitans) to commercial clean sand (control), sediment from an abandoned surface mine (mine), or sediment contaminated with coal combustion waste (CCW). By collecting eggs late in the breeding season, we obligated larvae to overwinter and spend a protracted amount of time exposed to contaminated sediments. The experiment was continued until all larvae either successfully completed metamorphosis or died (301 d). Larvae exposed to mine sediments accumulated significant levels of Pb and Zn, whereas larvae exposed to CCW-contaminated sediment accumulated significant levels of As, Se, Sr, and V. Larvae exposed to mine sediments suffered sublethal effects in the form of reduced growth and size at metamorphosis, but the proportion of larvae successfully completing metamorphosis (93%) was the same for both control and mine treatments. In contrast, larvae exposed to CCW-contaminated sediment suffered greatly reduced survival (13%) compared to both control and mine treatments. Moreover, among larvae in the CCW treatment, the majority of mortality occurred during the latter part the overwintering period (after day 205), corresponding to the onset of metamorphosis in the controls. Our results suggest that the length of the larval period may be one of many life-history or ecological characteristics that influence the sensitivity of aquatic breeding amphibians to environmental pollutants.
Arsenic and mercury tolerance and cadmium sensitivity in Arabidopsis plants expressing bacterial γ-glutamylcysteine synthetase
Authors: Li Yujing , Dhankher Om Parkash , Carreira Laura , Balish Rebecca S. , Meagher Richard B.
Published: May 2005

Cysteine sulfhydryl-rich peptide thiols are believed to play important roles in the detoxification of many heavy metals and metalloids such as arsenic, mercury, and cadmium in plants. The γ-glutamylcysteine synthetase (γ-ECS) catalyzes the synthesis of the dipeptidethiol γ-glu-cys (γ-EC), the first step in the biosynthesis of phytochelatins (PCs). Arabidopsis thaliana, engineered to express the bacterial γ-ECS gene under control of a strong constitutive actin regulatory sequence (A2), expressed γ-ECS at levels approaching 0.1% of total protein. In response to arsenic, mercury, and cadmium stresses, the levels of γ-EC and its derivatives, glutathione (GSH) and PCs, were increased in the A2::ECS transgenic plants to three- to 20-fold higher concentrations than the increases that occurred in wild-type (WT). Compared to cadmium and mercury treatments, arsenic treatment most significantly increased levels of γ-EC and PCs in both the A2::ECS transgenic and WT plants. The A2::ECS transgenic plants were highly resistant to arsenic and weakly resistant to mercury. Although exposure to cadmium produced three- to fivefold increases in levels of γ-EC-related peptides in the A2::ECS lines, these plants were significantly more sensitive to Cd(II) than WT and trace levels of Cd(II) blocked resistance to arsenic and mercury. A few possible mechanisms for γ-ECS-enhanced arsenic and mercury resistance and cadmium hypersensitivity are discussed.
Induction of ethoxy-resorufin-O-deethylase activity by halogenated aromatic hydrocarbons and polycyclic aromatic hydrocarbons in primary hepatocytes of the green frog (Rana esculenta)
Authors: Rankouhi Tanja Rouhani , Koomen Bas , Sanderson J. Thomas , Bosveld Albertus T.C. , Seinen Willem , van den Berg Martin
Published: May 2005

In this study, we measured the ethoxy-resorufin-O-deethylase (EROD) activity in primary hepatocytes of the common green frog Rana esculenta as a biomarker for cytochrome P4501A induction. We exposed hepatocytes derived from male and female frogs to several halogenated aromatic hydrocarbons, such as 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), 2,3,4,7,8-pentachlorodibenzofuran (PCDF), polychlorinated biphenyls (PCB-126, PCB-118), and polycyclic aromatic hydrocarbons such as benzo[a]pyrene (BaP), chrysene, anthracene, and pyrene. Exposure to PCB-118, anthracene, and pyrene, up to 1 μM, did not induce EROD activity, whereas TCDD and PCDF induced EROD activity maximally. In our primary frog hepatocytes, exposure to chrysene and BaP resulted in median effective concentration values (EC50) in the high nM range (82–1035 nM). Exposure to TCDD, PCDF, and PCB-126 resulted in EC50 values of 0.4 to 8, 0.07 to 0.7, and 3 to 133 nM, respectively, which is in the same range as EC50 values found in primary hepatocytes of birds. Compared to our frog hepatocytes, primary rat hepatocytes seem to be more sensitive to TCDD, chrysene, and BaP.
Stress synergy between environmentally realistic levels of copper and frost in the earthworm Dendrobaena octaedra
Authors: Bindesbøl Anne-Mette , Holmstrup Martin , Damgaard Christian , Bayley Mark
Published: May 2005

In their natural habitat, animals are exposed to a variety of stress factors, including extreme temperatures, low water availability, and toxic stress from chemical pollutants. In this study we examined the interaction between realistic environmental levels of soil-copper contamination and realistic winter temperatures on survival of the cosmopolitan freeze-tolerant earthworm Dendrobaena octaedra. These interactions were tested using a full factorial design with six copper concentrations between 0 and 200 mg Cu/kg dry soil and five temperatures from +2 to −8°C. A highly significant synergistic interaction existed that demonstrates that exposure to subzero temperatures significantly reduced copper tolerance and, conversely, that copper exposure significantly reduced freeze tolerance. Copper had no effect on glucose production, which is believed to be a major component of the cryoprotective system and the only known cryoprotectant in D. octaedra. This points to other mechanisms behind the observed synergy, possibly impaired osmoregulatory function of the cell membrane. The results support the working hypothesis that interactions between toxicants and dominant natural stress factors can alter the organisms' tolerance to these individual stressors.
Endocrine (sexual) disruption is not a prominent feature in the pike (Esox lucius), a top predator, living in english waters
Authors: Vine Emma , Shears Jan , van Aerle Ronny , Tyler Charles R. , Sumpter John P.
Published: May 2005

The high incidence of intersex roach (Rutilus rutilus) in some United Kingdom rivers that has been associated with exposure to sewage treatment works (STWs) effluent led us to hypothesize that top predator fish also may be affected by estrogenic chemicals, because they are likely to bioaccumulate lipophilic compounds through a predator-prey relationship. To investigate this possibility, pike (Esox lucius) were sampled both upstream and downstream of STWs and then examined for total estrogenic activity of their bile, as measured using a yeast-based estrogen assay to determine the degree of recent exposure of the pike to estrogens and vitellogenin induction, and for possible disruption of sexual development, as measured using histological analysis of the gonads. No evidence of severe disruption was found in the sampled fish, which came from 16 sampling sites that were representative of English rivers. However, 14% of pike were intersex, of which 15 of 16 showed patches of male germ cells among predominantly female gonadal tissue. The incidence of masculinization was independent of whether the pike had been sampled upstream or downstream of STWs. Although pike are gonochoristic, it is not known if this masculinization of presumptive female pike is normal or, instead, indicative of endocrine disruption. Vitellogenin concentrations were not elevated in male pike at sites either upstream or downstream of STWs. The results suggest that sexual disruption is not common in pike, a fish at the top of the food chain in the freshwaters of England.
Calculating life-cycle assessment effect factors from potentially affected fraction-based ecotoxicological response functions
Authors: van de Meent Dik , Huijbregts Mark A.J.
Published: May 2005

A new multisubstance potentially affected fraction (msPAF)-based method for calculating ecotoxicological effect factors for life-cycle assessment is introduced and compared to two other available methods of calculation. The new method is based on marginal increase of the msPAF of species. The method follows concentration-additive rules for pollutants with the same toxic mode of action (TMoA) and response-additive calculation rules for pollutants with independent action, and it combines a TMoA-specific factor, which is calculated differently in different methods, and a substance-specific factor, which is common to all methods. For 261 substances in 22 toxic modes of action, ecotoxicological effect factors for freshwater ecosystems have been calculated by different methods. Method-related differences appear to be rather small. Intersubstance differences in effect factors stem from differences in substance-specific toxic potencies, which span eight orders of magnitude, rather than from differences in TMoA-specific factors, which span only three orders of magnitude. Based on these insights, the choice of a calculation method seems to be a matter of personal (scientific) preference. The new hybrid msPAF method was greatly sensitive to data that usually are not known with sufficient certainty. Its use is recommended, entirely for reasons of scientific consistency, under strict conditions. When such conditions are not met or if necessary parameter values are unavailable, use of a fixed value for the TMoA-specific component is recommended.
Origins of the WHO Framework Convention on Tobacco Control
Authors: Roemer Ruth , Taylor Allyn , Lariviere Jean
Published: May 2005

The World Health Organization (WHO) Framework Convention on Tobacco Control originated in 1993 with a decision by Ruth Roemer and Allyn Taylor to apply to tobacco control Taylor’s idea that the WHO should utilize its constitutional authority to develop international conventions to advance global health. In 1995, Taylor and Ruth Roemer proposed various options to WHO, recommending the framework convention-protocol approach conceptualized by Taylor.

Despite initial resistance by some WHO officials, this approach gained wide acceptance. In 1996, the World Health Assembly voted to proceed with its development. Negotiations by WHO member states led the World Health Assembly in May 2003 to adopt by consensus the WHO Framework Convention on Tobacco Control—the first international treaty adopted under WHO auspices. The treaty formally entered into force for state parties on February 27, 2005.
Free Nicotine Replacement Therapy Programs vs Implementing Smoke-Free Workplaces: A Cost-Effectiveness Comparison
Authors: Ong Michael K. , Glantz Stanton A.
Published: May 2005

We compared the cost-effectiveness of a free nicotine replacement therapy (NRT) program with a statewide smoke-free workplace policy in Minnesota. We conducted 1-year simulations of costs and benefits. The number of individuals who quit smoking and the quality-adjusted life years (QALYs) were the measures of benefits. After 1 year, a NRT program generated 18 500 quitters at a cost of $7020 per quitter ($4440 per QALY), and a smoke-free workplace policy generated 10 400 quitters at a cost of $799 per quitter ($506 per QALY). Smoke-free work-place policies are about 9 times more cost-effective per new nonsmoker than free NRT programs are. Smoke-free workplace policies should be a public health funding priority, even when the primary goal is to promote individual smoking cessation.
The Role of Training in Global Tobacco Control Research
Authors: Kassel Jon D. , Ross Hana
Published: May 2005

Despite the pandemic nature of the tobacco control problem, little attention has been given to the role of research training in stemming the global tide of tobacco use. Tobacco research plays a critical role in both shaping policy and saving lives, and training new tobacco researchers is an important part of the tobacco control agenda.

There are several conceptual training models, all of which emphasize communicative partnerships and multidisciplinary approaches. It also is important to take cultural background and specificity into account when shaping research and training agendas.

We present a number of successful training initiatives and address both the strengths and the pitfalls of these endeavors.
The Landscape in Global Tobacco Control Research: A Guide to Gaining a Foothold
Authors: Lando Harry A. , Borrelli Belinda , Klein Laura C. , Waverley Linda P. , Stillman Frances A. , Kassel Jon D. , Warner Kenneth E.
Published: May 2005

Smoking prevalence is shifting from more- to less-developed countries. In higher-income countries, smoking surveillance data, tailored treatments, public health campaigns, and research-based policy implementation have led to a decrease in tobacco use. In low- and middle-income countries, translating research into practice and policy is integral for tobacco control.

We describe the landscape of existing resources, both financial and structural, to support global tobacco control research and strengthen research capacity in developing countries. We identify key organizations that support international efforts, provide examples of partnerships between developed and developing countries, and make recommendations for advancing global tobacco research.

There is a need for increased commitment from organizations to support global tobacco control research.
A Longitudinal Assessment of the Impact of Smoke-Free Worksite Policies on Tobacco Use
Authors: Bauer Joseph E. , Hyland Andrew , Li Qiang , Steger Craig , Cummings K. Michael
Published: May 2005

Objectives. In this cohort study, we assessed the impact of smoke-free work-site policies on smoking cessation behaviors.

Methods. Smokers were tracked as part of the Community Intervention Trial for Smoking Cessation. Telephone surveys were administered to 1967 employed smokers in 1993 and 2001. Data were gathered on personal and demographic characteristics, tobacco use behaviors, and restrictiveness of worksite smoking policies.

Results. People who worked in environments that changed to or maintained smoke-free policies between 1993 and 2001 were 1.9 times more likely (odds ratio [OR] = 1.92; 95% confidence interval [CI] = 1.11, 3.32) than people whose worksites did not do so to have stopped smoking by 2001. Continuing smokers decreased their average daily consumption by 2.57 cigarettes. People working in environments that had smoke-free policies in place in both 1993 and 2001 were 2.3 times more likely (OR=2.29; 95% CI=1.08, 4.45) than people not working in such environments to have quit by 2001, and continuing smokers reported a decline in average daily consumption of 3.85 cigarettes.

Conclusions. Smoke-free worksite policies help employees reduce their cigarette consumption and stop smoking.
Tobacco Control Competencies for US Medical Students
Authors: Geller Alan C. , Zapka Jane , Brooks Katie R. , Dube Catherine , Powers Catherine A. , Rigotti Nancy , O’Donnell Joseph , Ockene Judith
Published: May 2005

The 2004 National Action Plan for Tobacco Cessation recommended that the US Department of Health and Human Services convene a diverse group of experts to ensure that competency in tobacco dependence interventions be a core graduation requirement for all new physicians and other key health care professionals. Core competencies would guide the design of new modules and explicitly outline the learning objectives for all graduating medical students.

In 2002, the National Cancer Institute funded a consortium to develop, test, and integrate tobacco curricula at 12 US medical schools. Because there was neither an explicit set of tobacco competencies for medical schools nor a process to develop them, one of the consortium’s tasks was to articulate competencies and learning objectives.
Simple Models for Phosphorus Loss from Manure during Rainfall
Authors: Gérard‐Marchant Pierre , Walter M. Todd , Steenhuis Tammo S.
Published: May 2005

Mechanistic, predictive equations for phosphorus (P) transport in runoff from manure‐applied fields constitute a critical knowledge gap for developing nonpoint‐source pollution models. We derived two simple equations to describe the P release from animal manure during a rainfall event—one based on first‐order P desorption kinetics and one based on second‐order kinetics. The manure characteristics needed in the two kinetic equations are the maximum amount of water‐extractable phosphorus (WEP) and a characteristic desorption time. Water‐extractable P can be measured directly but currently the characteristic time can only be obtained by fitting experimental data. In addition, we evaluated two models usually used to estimate P loss from soil, the Elovitch equation and power function, both of which relate P loss to time. The models were tested against previously published data of P release from different manures under laboratory conditions. All equations fit the data well. Of the two kinetic equations, the second‐order model showed better agreement with the data than the first‐order model; for example, maximum relative differences between the model results and measured data were 2.6 and 4.7%, respectively. The characteristic times varied between 20 min for dairy manure and almost 100 min for poultry manure. The characteristic time did not appear to change with flow rate but decreased with smaller manure aggregates. The parameters for power‐function relationships could not be related to measured manure characteristics. These results provide the first step to process‐based approximations for predicting P release from manure with time during rainfall shortly after land application, when P losses are the greatest.
A Regional‐Scale Study on the Crop Uptake of Cadmium from Sandy Soils
Authors: Ingwersen Joachim , Streck Thilo
Published: May 2005

Plant uptake is one of the major pathways by which cadmium (Cd) in soils enters the human food chain. This study was conducted to investigate the uptake of Cd by crops from soils within the wastewater irrigation area (WIA) of Braunschweig (Germany) and to develop a simple process‐oriented model that is suited to predict Cd uptake at the regional scale. The sandy soils within the WIA (4300 ha) have received considerable loads of heavy metals by irrigation using municipal wastewater for up to 40 years. In 1998 and 1999, we sampled soil and plant material at 40 potato (Solanum tuberosum L.), 40 sugar beet (Beta vulgaris L.), and 32 winter wheat (Triticum aestivum L.) fields. In both years and for all three crops, we found close linear relationships between the Cd content of plant material and the Cd concentration in soil solution. For all three crops, we observed a trend of relatively increased Cd uptake in the year with the higher saturation deficit of the atmosphere. We interpret this to indicate that transpiration plays an important role in the Cd uptake of crops under the conditions of the WIA. In modeling the uptake of Cd by crops, we assume that uptake is proportional to mass flow, that is, the product of water transpired, Cd concentration in soil solution, and a plant‐specific empirical parameter. The simulations agreed well with the observed Cd contents in crops. Our model explained between 66 and 87% of the observed variance.
The Acetochlor Registration Partnership Surface Water Monitoring Program for Four Corn Herbicides
Authors: Hackett Amy G. , Gustafson David I. , Moran Sharon J. , Hendley Paul , van Wesenbeeck Ian , Simmons Nick D. , Klein Andrew J. , Kronenberg Joel M. , Fuhrman John D. , Honegger Joy L. , Hanzas John , Healy David , Stone Christopher T.
Published: May 2005

A surface drinking water monitoring program for four corn (Zea mays L.) herbicides was conducted during 1995–2001. Stratified random sampling was used to select 175 community water systems (CWSs) within a 12‐state area, with an emphasis on the most vulnerable sites, based on corn intensity and watershed size. Finished drinking water was monitored at all sites, and raw water was monitored at many sites using activated carbon, which was shown capable of removing herbicides and their degradates from drinking water. Samples were collected biweekly from mid‐March through the end of August, and twice during the off‐season. The analytical method had a detection limit of 0.05 μg L−1 for alachlor [2‐chloro‐N‐(2,6‐diethylphenyl)‐N‐(methoxymethyl)‐acetamide] and 0.03 μg L−1 for acetochlor [2‐chloro‐N‐(ethoxymethyl)‐N‐(2‐ethyl‐6‐methylphenyl)‐acetamide], atrazine [6‐chloro‐N‐ethyl‐N′‐(1‐methylethyl)‐1,3,5‐triazine‐2,4‐diamine], and metolachlor [2‐chloro‐N‐(2‐ethyl‐6‐methylphenyl)‐N‐(2‐methoxy‐1‐methylethyl)‐acetamide]. Of the 16528 drinking water samples analyzed, acetochlor, alachlor, atrazine, and metolachlor were detected in 19, 7, 87, and 53% of the samples, respectively. During 1999–2001, samples were also analyzed for the presence of six major degradates of the chloroacetanilide herbicides, which were detected more frequently than their parent compounds, despite having higher detection limits of 0.1 to 0.2 μg L−1 Overall detection frequencies were correlated with product use and environmental fate characteristics. Reservoirs were particularly vulnerable to atrazine, which exceeded its 3 μg L−1 maximum contaminant level at 25 such sites during 1995–1999. Acetochlor annualized mean concentrations (AMCs) did not exceed its mitigation trigger (2 μg L−1) at any site, and comparisons of observed levels with standard measures of human and ecological hazards indicate that it poses no significant risk to human health or the environment.