Exposure assessment at a PCDD/F contaminated site in Sweden--field measurements of exposure media and blood serum analysis

BACKGROUND, AIM, AND SCOPE

The main pathway for human exposure to the highly toxic polychlorinated-p-dioxins and polychlorinated furans [polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs)] is via dietary intake. Other exposure pathways may, however, be important in close proximity to point sources, such as wood preservation sites, where PCDD/F contaminated chlorophenols (CP) were previously used. In this study, a heavily PCDD/F contaminated CP saw mill site in Sweden was investigated. Human exposure through a broad spectrum of exposure pathways was assessed. Such studies are in demand since the question whether contaminated sites represent a current or future risk can only be answered by detailed site-specific risk assessments.

MATERIALS AND METHODS

Sampling of exposure media (soil, air, groundwater, raspberries, carrots, potatoes, grass, milk, eggs, and chicken fodder) was made. Exposure media concentrations and congener distribution patterns were used to investigate the mobilization of PCDD/Fs from soil to the environment and to calculate exposure levels for adults. Blood serum levels from site-exposed and control individuals were also analyzed.

RESULTS

Congener distribution patterns at the site were generally dominated by a specific marker congener (1234678-HpCDF), which is highly abundant in the polluted soil. The dioxin toxic equivalents (TEQ) concentrations were notably elevated as compared to national reference samples for most exposure media, and the marker congener was a major contributor to increased TEQ levels. There were also indications of soil-to-air volatilization of tetra- and penta-CDD/Fs. People who participated in the restoration of a contaminated building showed higher levels of 1234678-HpCDF compared to controls, and calculated exposure levels suggest that several site-specific exposure routes may be of importance for the daily intake of PCDD/F. CONCLUSIONS, RECOMMENDATIONS, AND PERSPECTIVES: Despite low mobility of higher chlorinated PCDD/Fs, these contaminants were transferred from the polluted soil to the surroundings and into human tissue. The extent of increased exposure from contaminated sites depends on the PCDD/F source strength of the soil, composition of the pollution, human activities, and dietary patterns of the residents. Impact from the contaminated soil on other exposure media was seen also for areas with low to moderate soil contamination. In the future, not only the levels of PCDD/F soil pollution but also the composition must be considered in risk assessments of contaminated sites.

Modeling aerosol suspension from soils and oceans as sources of micropollutants to air

Soil and marine aerosol suspension are two physical mass transfer processes that are not usually included in models describing fate and transport of environmental pollutants. Here, we review the literature on soil and marine aerosol suspension and estimate aerosol suspension mass transfer velocities for inclusion in multimedia models, as a global average and on a 1 x 1 scale. The yearly, global average mass transfer velocity for soil aerosol suspension is estimated to be 6 x 10(-10)mh(-1), approximately an order of magnitude smaller than marine aerosol suspension, which is estimated to be 8 x 10(-9)mh(-1). Monthly averages of these velocities can be as high as 10(-7)mh(-1) and 10(-5)mh(-1) for soil and marine aerosol suspension, respectively, depending on location. We use a unit-world multimedia model to analyze the relevance of these two suspension processes as a mechanism that enhances long-range atmospheric transport of pollutants. This is done by monitoring a metric of long-range transport potential, phi-one thousand (phi1000), that denotes the fraction of modeled emissions to air, water or soil in a source region that reaches a distance of 1000 km in air. We find that when the yearly, globally averaged mass transfer velocity is used, marine aerosol suspension increases phi1000 only fractionally for both emissions to air and water. However, enrichment of substances in marine aerosols, or speciation between ionic and neutral forms in ocean water may increase the influence of this surface-to-air transfer process. Soil aerosol suspension can be the dominant process for soil-to-air transfer in an emission-to-soil scenario for certain substances that have a high affinity to soil. When a suspension mass transfer velocity near the maximum limit is used, soil suspension remains important if the emissions are made to soil, and marine aerosol suspension becomes important regardless of if emissions are made to air or water compartments. We recommend that multimedia models designed to assess the environmental fate and long-range transport behavior of substances with a range of chemical properties include both aerosol suspension processes, using the mass transfer velocities estimated here.

A multi-individual pharmacokinetic model framework for interpreting time trends of persistent chemicals in human populations: application to a postban situation

BACKGROUND

Human milk and blood are monitored to detect time trends of persistent organic pollutants (POPs) in humans. It is current practice to use log-linear regression to fit time series of averaged cross-sectional biomonitoring data, here referred to as cross-sectional trend data (CSTD).

OBJECTIVE

The goals of our study are to clarify the interpretation of half-lives derived from fitting exponential functions to declining CSTD and to provide a method of estimating human elimination half-lives from CSTD collected in a postban situation.

METHODS

We developed a multi-individual pharmacokinetic model framework and present analytical solutions for a postban period. For this case, the framework quantitatively describes the relationships among the half-life for reduction of body burdens of POPs derived from CSTD, the half-life describing decline in daily intake, and the half-life of elimination from the human body.

RESULTS

The half-life derived from exponential fitting of CSTD collected under postban conditions describes the exposure trend and is independent of human elimination kinetics. We use a case study of DDT (dichlorodiphenyltrichloroethane) to show that CSTD can be combined with exposure data obtained from total diet studies to estimate elimination kinetics of POPs for humans under background exposure conditions.

CONCLUSIONS

CSTD provide quantitative information about trends in human exposure and can be combined with exposure studies to estimate elimination kinetics. The full utility of these data has not been exploited so far. An efficient and informative monitoring strategy for banned POPs in humans would coordinate sampling of consistent sets of CSTD from young adults with total diet studies.

Empirical investigation of the Junge variability-lifetime relationship using long-term monitoring data on polychlorinated biphenyl concentrations in air

In 1974, Junge derived an empirical relationship between the variability of concentrations of volatile trace gases in air at remote locations and their atmospheric residence time. Here, the Junge relationship is adapted to incorporate the deposition and revolatilization of semivolatile chemicals and applied to interpret nearly a decade of data on polychlorinated biphenyl (PCB) concentrations in air. A multimedia fate model, which accounts for deposition and revolatilization, is used to estimate the characteristic travel distance (CTD) for PCBs, where CTD serves as a measure of the effective atmospheric lifetime for semivolatile organic chemicals. Data are taken from sites of the Integrated Atmospheric Deposition Network in the North American Great Lakes and the Alert monitoring station in the Arctic, which is operated by the Canadian Northern Contaminants Program. Five factors that may introduce variability into measured concentrations are defined. By suppressing the effect of three of these factors in the data analysis, we identified variability consistent with the Junge relationship in many of the annual data sets (62%), with the relationship showing statistical significance (p < 0.05) in 23% of these annual data sets. The more remote monitoring sites from the Great Lakes region display the highest number of statistically significant Junge-type relationships between the variability in concentrations in air and estimated long-range transport potential in air. At sites in close proximity to areas of high population density, variability in PCB concentrations in air displays patterns that are consistent with primary or secondary temperature-driven volatilization sources. Analysis of variability in long-term monitoring data, using the techniques developed and illustrated here, provides useful insights into the factors that control the behavior of persistent semivolatile chemicals in the environment.

Modeling the global fate and transport of perfluorooctanoic acid (PFOA) and perfluorooctanoate (PFO) emitted from direct sources using a multispecies mass balance model

The global-scale fate and transport processes of perfluorooctanoic acid (PFOA) and perfluorooctanoate (PFO) emitted from direct sources were simulated using a multispecies mass balance model over the period 1950 to 2010. The main goal of this study was to assess the atmospheric and oceanic long-range transport potential of direct source emissions and the implications for the contamination of terrestrial and marine systems worldwide. Consistent with previous modeling studies, ocean transport was found to be the dominant pathway for delivering PFO(A) associated with direct sources to the Arctic marine environment regardless of model assumptions. The modeled concentrations for surface ocean waters were insensitive to assumptions regarding physical-chemical properties and emission mode of entry and were in reasonable agreement with available monitoring data from the Northern Hemisphere. In contrast, model outputs characterizing atmospheric transport potential were highly sensitive to model assumptions, especiallythe assumed value of the acid dissociation constant (pKa). However, the complete range of model results for scenarios with different assumptions about partitioning and emissions provide evidence that the atmospheric transport of directly emitted PFO(A) can deliver this substance to terrestrial environments distant from sources. Additional studies in remote or isolated terrestrial systems may provide further insight into the scale of contamination actually attributable to direct sources.

Modeling the global fate and transport of perfluorooctanoic acid (PFOA) and perfluorooctanoate (PFO) emitted from direct sources using a multispecies mass balance model

The global-scale fate and transport processes of perfluorooctanoic acid (PFOA) and perfluorooctanoate (PFO) emitted from direct sources were simulated using a multispecies mass balance model over the period 1950 to 2010. The main goal of this study was to assess the atmospheric and oceanic long-range transport potential of direct source emissions and the implications for the contamination of terrestrial and marine systems worldwide. Consistent with previous modeling studies, ocean transport was found to be the dominant pathway for delivering PFO(A) associated with direct sources to the Arctic marine environment regardless of model assumptions. The modeled concentrations for surface ocean waters were insensitive to assumptions regarding physical-chemical properties and emission mode of entry and were in reasonable agreement with available monitoring data from the Northern Hemisphere. In contrast, model outputs characterizing atmospheric transport potential were highly sensitive to model assumptions, especiallythe assumed value of the acid dissociation constant (pKa). However, the complete range of model results for scenarios with different assumptions about partitioning and emissions provide evidence that the atmospheric transport of directly emitted PFO(A) can deliver this substance to terrestrial environments distant from sources. Additional studies in remote or isolated terrestrial systems may provide further insight into the scale of contamination actually attributable to direct sources.

Mercury cycling and species mass balances in four North American lakes

A mass balance model for mercury based on the fugacity concept is applied to Lake Superior, Lake Michigan, Onondaga Lake and Little Rock Lake to evaluate model performance, analyze cycling of three mercury species groups (elemental, divalent and methyl mercury), and identify important processes that determine the source-to-concentration relationship of the three mercury species groups in these lakes. This model application to four disparate ecosystems is an extension of previous applications of fugacity-based models describing mercury cycling. The model performs satisfactorily following site-specific parameterization, and provides an estimate of minimum rates of species interconversion that compare well with literature. Volatilization and sediment burial are the main processes removing mercury from the lakes, and uncertainty analyses indicate that air-water exchange of elemental mercury and water-sediment exchange of divalent mercury attached to particles are influential in governing mercury concentrations in water. Any new model application or field campaign to quantify mercury cycling in a lake should consider these processes as important.

Measuring and modeling short-term variability of PCBs in air and characterization of urban source strength in Zurich, Switzerland

Diel (24-h) variations of concentrations of polychlorinated biphenyls (PCBs) in air are reported at two sites in Zurich, Switzerland, a city surrounded by hills. One site was located in the valley near the city center and the other site was on a hill called Uetliberg, 411 m higher and about 5 km distant from the city center site. Air samples were collected simultaneously at both sites over 4-h time periods for 3 consecutive days under stable meteorological conditions during a high pressure system in August 2007. PCB concentrations at the city site were markedly higher than those at Uetliberg, indicating that the city site is influenced by urban sources of PCBs. Concentrations measured at both sites show a clear diel cycle but have opposite phases: in the city concentrations were lower during the day and higher at night, while at Uetliberg concentrations were higher during the day and lower at night. These observations are explained and interpreted using a multimedia mass balance model that includes a stable night-time inversion layer that formed over the city but below the hilltop site. At Uetliberg the concentration of PCBs is consistent with background levels and the diel concentration pattern can be explained bytemperature-mediated air-surface exchange and the influence of nearby woodland canopies. The diel pattern and concentrations in the city are attributable to volatilization from urban sources. We have developed a new method to estimate the strength of the urban PCB source using the model scenarios for the two sampling sites. Emission estimates derived from this method are in good agreement with earlier estimates derived from PCB production, consumption, and usage estimates. This study demonstrates the potential for estimating the strength of diffuse, regional sources of persistent organic pollutants (POPs) using a combined measurement and modeling approach. Such studies can provide important information to derive regional and national POPs emission inventories as required under the Stockholm Convention, and to quantify the effectiveness of actions to reduce POP emissions.

Contribution of volatile precursor substances to the flux of perfluorooctanoate to the Arctic

Perfluorooctanoate (PFO) has recently been found in remote ocean water and Arctic samples, despite not having been used in significant quantities in remote areas. Two main scenarios for the contamination of the Arctic by PFO have been suggested: (i) direct emissions of PFO and oceanic transport to the Arctic and (ii) emissions of volatile precursor substances that are transported and oxidized in the atmosphere to form PFO, which is subsequently deposited to the Arctic. Focusing on the atmospheric transport pathway, we compare the importance of fluorotelomer alcohols (FTOHs) and perfluorooctyl sulfonamidoethanols (FOSEs) for PFO deposition to the Arctic. Using a global scale multispecies mass balance model, we simultaneously calculate the transport, degradation, partitioning, and deposition of precursor substances, intermediate degradation products, and PFO and compare model results to field measurements. Prior to 2002, the modeled deposition fluxes of PFO to the Arctic originating from FOSEs and FTOHs are of a similar magnitude, and total estimated deposition compares well with deposition measurements for Arctic ice cores. However, the model underpredicts recent measurements of FOSEs in Arctic air, indicating that there may be additional emissions not taken into account. Using Monte Carlo calculations we quantify the uncertainties in our model results and identify that emission estimates, degradation yields, and degradation rate constants are the most influential input parameters controlling the estimated deposition of PFO to the Arctic.

Dependence of persistence and long-range transport potential on gas-particle partitioning in multimedia models

A novel approach of modeling gas-particle partitioning using polyparameter linear free energy relationships (ppLFERs) is implemented into three different multimedia box models (the OECD Pov and LRTP screening tool (The Tool), ChemRange, and CliMoChem) and compared to approaches based on the octanol-air partition coefficient (K(OA)). In all three multimedia models, calculated overall persistence is not strongly influenced (differences < 3%) by the gas-particle partitioning approach selected. The long-range transport potential (LRTP) is more sensitive to the choice of the gas-particle partitioning model. In CliMoChem, the LRTP of polar chemicals is higher if the ppLFER gas-particle partitioning approach is applied, with differences up to a factor of 2. Modeled concentrations of polar chemicals in Arctic air are also higher in the ppLFER version of CliMoChem. The model results obtained with the ppLFER approach are in good agreement with measured concentrations of alpha-HCH, methoxychlor, and trifluralin in Arctic air, whereas results from the K(OA)-based version of the model are in some cases lower by a factor of 10-100. If the required chemical property data are available, the ppLFER approach holds considerable potential to improve the gas-particle partitioning description for polar chemicals in multimedia models.

The origin and significance of short-term variability of semivolatile contaminants in air

Persistent semivolatile contaminants such as polychlorinated biphenyls (PCBs) cycle between air and surface media in the environment. At different locations and times, PCB concentrations in air over a diel (24-hour) period have been observed to have maxima either during the day or at night. These observations have been interpreted as evidence of temperature-mediated air-surface exchange and of degrading reactions with hydroxyl radicals in the atmosphere. However, a general explanation of the processes responsible for the observed diel variability in concentrations has not been provided. Here, we interpret diel monitoring data using a multimedia mass balance model parametrized with local data on temperature, wind speed, atmospheric mixing height, and hydroxyl radical concentrations. We demonstrate that four factors are sufficient to account for the variability of PCB concentrations in air over a diel period; temperature, local atmospheric stability, hydroxyl radical concentration, and source type. We apply the model to re-interpret past diel monitoring studies and find that the observed patterns of concentrations can be rationalized by consideration of these factors. Using insights from this study, future diel monitoring campaigns can be targeted to observe the influence of specific fate and transport processes. Such studies will contribute to more accurate understanding of the processes controlling the short-term local, and long-term global fate of persistent semivolatile contaminants.

Estimating enthalpy of vaporization from vapor pressure using Trouton's rule

The enthalpy of vaporization of liquids and subcooled liquids at 298 K (delta H(VAP)) is an important parameter in environmental fate assessments that consider spatial and temporal variability in environmental conditions. It has been shown that delta H(VAP)P for non-hydrogen-bonding substances can be estimated from vapor pressure at 298 K (P(L)) using an empirically derived linear relationship. Here, we demonstrate that the relationship between delta H(VAP)and PL is consistent with Trouton's rule and the ClausiusClapeyron equation under the assumption that delta H(VAP) is linearly dependent on temperature between 298 K and the boiling point temperature. Our interpretation based on Trouton's rule substantiates the empirical relationship between delta H(VAP) degree and P(L) degrees for non-hydrogen-bonding chemicals with subcooled liquid vapor pressures ranging over 15 orders of magnitude. We apply the relationship between delta H(VAP) degrees and P(L) degrees to evaluate data reported in literature reviews for several important classes of semivolatile environmental contaminants, including polycyclic aromatic hydrocarbons, chlorobenzenes, polychlorinated biphenyls and polychlorinated dibenzo-dioxins and -furans and illustrate the temperature dependence of results from a multimedia model presented as a partitioning map. The uncertainty associated with estimating delta H(VAP)degrees from P(L) degrees using this relationship is acceptable for most environmental fate modeling of non-hydrogen-bonding semivolatile organic chemicals.

Alternative approaches for modeling gas-particle partitioning of semivolatile organic chemicals: model development and comparison

We present a novel model of gas-particle partitioning based on polyparameter linear free energy relationships (ppLFERs) that is capable of representing a broad range of aerosol properties. We apply the model to semivolatile organic chemicals including PCBs, DDT, and polar pesticides, and compare it to a widely adopted model based on the octanol-air partition coefficient (K(OA)). For nonpolar chemicals and cases where sorption to aerosols is dominated by absorption into organic matter, the two models are highly correlated and both are appropriate. Significant differences between the models are found for (a) polar chemicals and (b) aerosols with low organic matter content. The explicit description of polar interactions in the ppLFER approach implies stronger interactions between chemicals and aerosols than the K(OA)-based model, which describes polar interactions only implicitly and to a limited extent. Practical application of the ppLFER-based model to a wide range of chemicals is currently limited by data gaps in measured Abraham solvation parameters and uncertainties in estimation methods.

Modeling global-scale fate and transport of perfluorooctanoate emitted from direct sources

The long-term (1950-2050) global fate of perfluorooctanoate (PFO) is investigated using the global distribution model, GloboPOP. The model is used to test the hypotheses that direct PFO emissions can account for levels observed in the global oceans and that ocean water transport to the Arctic is an important global distribution pathway. The model emission scenarios are derived from historical and projected PFO emissions solely from direct sources. Modeled ocean water concentrations compare favorably to observed PFO concentrations in the world's oceans and thus ocean inventories can be accounted for by direct sources. The model results support the hypothesis that long-range ocean transport of PFO to the Arctic is important and estimate a net PFO influx of approximately 8-23 tons per year flowing into the model's Northern Polar zone in 2005, an amount at least 1 order of magnitude greater than estimated PFO flux to the Arctic from potential indirect sources such as atmospheric transport and degradation of fluorotelomer alcohols. Modeled doubling times of ocean water concentrations in the Arctic between 1975 and 2005 of approximately 7.5-10 years are in good agreement with doubling times of PFO in Arctic biota estimated from monitoring data. The model is further applied to predict future trends in PFO contamination levels using forecasted (2005-2050) direct emissions, including substantial reductions committed to by industry. Modeled ocean water concentrations in zones near to sources decline markedly after 2005, whereas modeled concentrations in the Arctic are predicted to continue to increase until approximately 2030 and show no significant decrease for the remaining 20 years of the model simulation. Since water is the primary exposure medium for Arctic biota, these model results suggest that concentrations in Arctic biota may continue to rise long after direct emissions have been substantially reduced or eliminated.

Improving data quality for environmental fate models: a least-squares adjustment procedure for harmonizing physicochemical properties of organic compounds

Physicochemical properties (vapor pressure, aqueous solubility, octanol solubility, Henry's law constant, and octanol-air and octanol-water partition coefficients) and their temperature dependencies are required for fate modeling of environmental pollutants. To be internally consistent, measured values for these properties often must be adjusted. The goal of adjusting the property values for consistency is to more accurately estimate the true values. However, consistency and accuracy are not synonymous. If there are systematic errors in one property, then adjustment for consistency may reduce the accuracy of other property data. Here, we provide methods for achieving consistency and improving accuracy in the selection of partitioning properties from literature sources. First, we show that a widely used procedure does not always minimize the adjustments of property values derived from the literature when harmonizing them according to thermodynamic constraints. In such cases, the final adjusted values (FAVs) are unnecessarily different from the literature-derived values (LDVs) selected from measurements. We present an improved procedure based on the theory of least squares that minimizes the adjustment of LDVs and allows quantitative propagation of uncertainty from LDVs to FAVs. When this procedure is applied to partitioning properties for 30 organic chemicals, FAVs obtained differ by up to 30% from those calculated with the current adjustment procedure. Second, we point out that the adjustment procedure is only appropriate for correcting random errors in measurement data. Biased LDVs must be identified and corrected prior to harmonization. Using a set of 16 PCB congeners as a case study, we provide methods to identify biased data and discuss possible sources of bias. We present a new interpretation of property data for the PCBs and a new set of internally consistent properties and quantitative structure-property relationships that we recommend as the best currently available.

Assessing the influence of climate variability on atmospheric concentrations of polychlorinated biphenyls using a global-scale mass balance model (BETR-global)

We introduce a new global-scale multimedia contaminant fate model (the Berkeley-Trent Global Model; BETR-Global) that integrates global climate data from the National Centers for Environmental Prediction (NCEP). BETR-Global represents the global environment as a connected set of 288 multimedia regions on a 15 degrees grid. We evaluate the model by simulating the global fate and transport of seven PCB congeners over a 70 year period and find satisfactory agreement between model output and observations of atmospheric PCB concentrations at 11 long-term monitoring stations in the Northern Hemisphere. We demonstrate the use of the model as a tool for understanding global pollutant dynamics by examining the hypothesis that variability in global-scale climate conditions, as reflected bythe North Atlantic Oscillation (NAO), influences atmospheric PCB concentrations in the Northern Hemisphere. We estimate that the maximum variability in atmospheric PCB concentrations attributable to NAO variability is approximately a factor of 2. The influence of variability in the NAO on PCB concentrations in air is most likely to be observed in the winter and spring at monitoring sites in Northern Europe and the Arctic. Analysis of long-term monitoring data from 11 sites shows some statistically significant relationships between NAO indices and atmospheric PCB concentrations during the winter and spring. Giving consideration to competing factors that influence atmospheric PCB concentrations, longer time series of monitoring data are required to fully evaluate the modeling results and to improve our understanding of the role of climate variability on the long-term fate of persistent semivolatile pollutants.

Mass balance for mercury in the San Francisco Bay area

We have developed and illustrated a general regional multi-species model that describes the fate and transport of mercury in three forms, elemental, divalent, and methylated, in a generic regional environment including air, soil, vegetation, water, and sediment. The objectives of the model are to describe the fate of the three forms of mercury in the environment and to determine the dominant physical sinks that remove mercury from the system. Chemical transformations between the three groups of mercury species are modeled by assuming constant ratios of species concentrations in individual environmental media. We illustrate and evaluate the model with an application to describe the fate and transport of mercury in the San Francisco Bay Area of California. The model successfully rationalizes the identified sources with observed concentrations of total mercury and methyl mercury in the San Francisco Bay Estuary. The mass balance provided by the model indicates that continental and global background sources control mercury concentrations in the atmosphere but that loadings to water in the San Francisco Bay Estuary are dominated by runoff from the Central Valley catchment and remobilization of contaminated sediments deposited during past mining activities. The model suggests that the response time of mercury concentrations in the San Francisco Bay Estuary to changes in loadings is long, on the order of 50 years.

Genotype, dietary manipulation and food allocation affect indices of welfare in broiler breeders

1. An experiment was performed to compare the welfare of three broiler breeder genotypes (Label Rouge (LA), experimental dwarf (ER) and standard (SR)) fed on a Control or high Fibre diet. The LA birds were fed ad libitum and the other groups were reared to their recommended body weight targets. A group of standard broiler breeders was also fed a restricted amount of food, but to a lesser degree than SR, to achieve the same proportion of body weight (SE) as ER relative to ad libitum-fed dwarfs based on previous research. LA, ER, SR and SE are referred to as 'groups' in the text. 2. Welfare was assessed by comparing time budgets and heterophil-lymphocyte ratios (HL ratios) at 5, 10 and 15 weeks and immune responses at 15 weeks of age. In addition the weight and water content of the gastrointestinal tract at 4-h intervals at the end of the experiment were studied in LA and SR fed on both diets. 3. Body weights of LA, ER and SR fed on the Fibre diets were depressed and LA ate less of the Fibre than the Control diet. The coefficient of variation of body weight at 15 weeks was 7.9% in LA and similar (10.8 to 11.6%) in the other groups. 4. Drinking, litter-directed behaviour, resting and standing were affected by a group x age interaction with restricted birds showing increased drinking over time and less time spent resting compared to LA. The behaviour of ER birds was similar to SE. 5. HL ratios were within the normal biological range although all restricted-fed birds had an elevated HL ratio at 10 weeks of age relative to week 5 whereas LA birds had a reduced HL ratio at 15 weeks relative to 5 and 10 weeks of age. Immune responses were lower in ER and SE and the highest response was in SR. 6. No effects of diet were identified on behaviour, white blood cell counts or HL ratio. 7. With the exception of the crop, the dry weights of digesta in each section of the gut were similar in LA and SR birds. The results suggest that drinker-directed activity might be a substitute for foraging rather than an attempt to increase gut fill. 8. It is concluded that the replacement of standard with dwarf broiler breeders may improve the welfare of commercial flocks of broiler breeders by decreasing the degree of food restriction resulting in favourable changes in behaviour, for example, reduced 'drinker-directed' behaviour.

Multimedia persistence as an indicator of potential for population-level intake of environmental contaminants

Although intuitively it is apparent that population-level exposure to contaminants dispersed in the environment must be related to the persistence of the contaminant, there has been little effort to quantify this link formally. In this paper we investigate the relationship between overall persistence and/or overall residence time in a multimedia exposure environment and the population-level intake of contaminants as expressed by intake fraction (iF), the cumulative fraction of chemical emitted to the environment that is taken up by members of the population. We demonstrate that for any given contaminant and emission scenario the definition of iF implies that it is directly proportional to the overall multimedia persistence (Pov), or the overall multimedia residence time (Tov). The proportionality constant has dimensions of time and represents the characteristic time for population intake (CTI) of the chemical from the environment. We then apply the CalTOX fate and exposure model to explore how Tov and CTI combine to determine the magnitude of iF We find that CTI has a narrow range of possible values relative to Tov across multiple chemicals and emissions scenarios. We use data from the Canadian Environmental Protection Act Priority Substance List (PSL1) Assessments and multimedia Pov to show that exposure assessments based on empirical observation are consistent with interpretations from the model. Results indicate that Pov derived from screening-level assessments of persistence, bioaccumulation potential, and toxicity (PBT) is a useful indicator of the potential for population-level exposure.

Modelling the fate of persistent organic pollutants in Europe: parameterisation of a gridded distribution model

A regionally segmented multimedia fate model for the European continent is described together with an illustrative steady-state case study examining the fate of gamma-HCH (lindane) based on 1998 emission data. The study builds on the regionally segmented BETR North America model structure and describes the regional segmentation and parameterisation for Europe. The European continent is described by a 5 degrees x5 degrees grid, leading to 50 regions together with four perimetric boxes representing regions buffering the European environment. Each zone comprises seven compartments including; upper and lower atmosphere, soil, vegetation, fresh water and sediment and coastal water. Inter-regions flows of air and water are described, exploiting information originating from GIS databases and other georeferenced data. The model is primarily designed to describe the fate of Persistent Organic Pollutants (POPs) within the European environment by examining chemical partitioning and degradation in each region, and inter-region transport either under steady-state conditions or fully dynamically. A test case scenario is presented which examines the fate of estimated spatially resolved atmospheric emissions of lindane throughout Europe within the lower atmosphere and surface soil compartments. In accordance with the predominant wind direction in Europe, the model predicts high concentrations close to the major sources as well as towards Central and Northeast regions. Elevated soil concentrations in Scandinavian soils provide further evidence of the potential of increased scavenging by forests and subsequent accumulation by organic-rich terrestrial surfaces. Initial model predictions have revealed a factor of 5-10 underestimation of lindane concentrations in the atmosphere. This is explained by an underestimation of source strength and/or an underestimation of European background levels. The model presented can further be used to predict deposition fluxes and chemical inventories, and it can also be adapted to provide characteristic travel distances and overall environmental persistence, which can be compared with other long-range transport prediction methods.

BETR-World: a geographically explicit model of chemical fate: application to transport of alpha-HCH to the Arctic

The Berkeley-Trent (BETR)-World model, a 25 compartment, geographically explicit fugacity-based model is described and applied to evaluate the transport of chemicals from temperate source regions to receptor regions (such as the Arctic). The model was parameterized using GIS and an array of digital data on weather, oceans, freshwater, vegetation and geo-political boundaries. This version of the BETR model framework includes modification of atmospheric degradation rates by seasonally variable hydroxyl radical concentrations and temperature. Degradation rates in all other compartments vary with seasonally changing temperature. Deposition to the deep ocean has been included as a loss mechanism. A case study was undertaken for alpha-HCH. Dynamic emission scenarios were estimated for each of the 25 regions. Predicted environmental concentrations showed good agreement with measured values for the northern regions in air, and fresh and oceanic water and with the results from a previous model of global chemical fate. Potential for long-range transport and deposition to the Arctic region was assessed using a Transfer Efficiency combined with estimated emissions. European regions and the Orient including China have a high potential to contribute alpha-HCH contamination in the Arctic due to high rates of emission in these regions despite low Transfer Efficiencies. Sensitivity analyses reveal that the performance and reliability of the model is strongly influenced by parameters controlling degradation rates.

Modeling transport and deposition of contaminants to ecosystems of concern: a case study for the Laurentian Great Lakes

Transfer efficiency (TE) is introduced as a model output that can be used to characterize the relative ability of chemicals to be transported in the environment and deposited to specific target ecosystems. We illustrate this concept by applying the Berkeley-Trent North American contaminant fate model (BETR North America) to identify organic chemicals with properties that result in efficient atmospheric transport and deposition to the Laurentian Great Lakes. By systematically applying the model to hypothetical organic chemicals that span a wide range of environmental partitioning properties, we identify combinations of properties that favor efficient transport and deposition to the Lakes. Five classes of chemicals are identified based on dominant transport and deposition pathways, and specific examples of chemicals in each class are identified and discussed. The role of vegetation in scavenging chemicals from the atmosphere is assessed, and found to have a negligible influence on transfer efficiency to the Great Lakes. Results indicate chemicals with octanol-water (K(ow)) and air-water (K(aw)) partition coefficients in the range of 10(5)-10(7) and 10(-4)-10(-1) combine efficient transport and deposition to the Great Lakes with potential for biaccumulation in the aquatic food web once they are deposited. A method of estimating the time scale for atmospheric transport and deposition process is suggested, and the effects of degrading reactions in the atmosphere and meteorological conditions on transport efficiency of different classes of chemicals are discussed. In total, this approach provides a method of identifying chemicals that are subject to long-range transport and deposition to specific target ecosystems as a result of their partitioning and persistence characteristics. Supported by an appropriate contaminant fate model, the approach can be applied to any target ecosystem of concern.

Bladder dysfunction in Duchenne muscular dystrophy

Although bladder function is thought to be unaffected in Duchenne muscular dystrophy, 46/88 boys interviewed had urinary problems. Nine underwent video urodynamics, showing in eight a small capacity, hyperreflexic bladder, and in the ninth (post spinal surgery) hyperreflexia and detrusor sphincter dyssynergia. Urinary dysfunction is a treatable feature of DMD.

A dynamic mass budget for toxaphene in North America

A continental-scale dynamic mass budget for toxaphene in North America is presented, based on available information on physicochemical properties, usage patterns, and reported environmental concentrations and using the Berkeley-Trent North American mass balance contaminant fate model (BETR North America). The model describes contaminant fate in 24 ecological regions of North America, including advective transport between regions in the atmosphere, freshwater, and near-shore coastal water. The dynamic mass budget accounts for environmental partitioning, transport, and degradation of the estimated 534 million kg of toxaphene that were used in North America as an insecticide and piscicide between 1945 and 2000. Satisfactory agreement exists between model results and current and historically reported concentrations of toxaphene in air, water, soil, and sediments throughout North America. An estimated 15 million kg of toxaphene are believed to remain in active circulation in the North American environment in the year 2000, with the majority in soils in the southern United States and Mexico, where historic usage was highest. Approximately 70% of total toxaphene deposition from the atmosphere to the Great Lakes is attributed to sources outside the Great Lakes Basin, and an estimated total of 3.9 million kg of toxaphene have been transported to this region from other parts of the continent. The toxaphene mass budget presented here is believed to be the first reported continental-scale multimedia mass budget for any contaminant.

Evaluating and expressing the propagation of uncertainty in chemical fate and bioaccumulation models

First-order analytical sensitivity and uncertainty analysis for environmental chemical fate models is described and applied to a regional contaminant fate model and a food web bioaccumulation model. By assuming linear relationships between inputs and outputs, independence, and log-normal distributions of input variables, a relationship between uncertainty in input parameters and uncertainty in output parameters can be derived, yielding results that are consistent with a Monte Carlo analysis with similar input assumptions. A graphical technique is devised for interpreting and communicating uncertainty propagation as a function of variance in input parameters and model sensitivity. The suggested approach is less calculationally intensive than Monte Carlo analysis and is appropriate for preliminary assessment of uncertainty when models are applied to generic environments or to large geographic areas or when detailed parameterization of input uncertainties is unwarranted or impossible. This approach is particularly useful as a starting point for identification of sensitive model inputs at the early stages of applying a generic contaminant fate model to a specific environmental scenario, as a tool to support refinements of the model and the uncertainty analysis for site-specific scenarios, or for examining defined end points. The analysis identifies those input parameters that contribute significantly to uncertainty in outputs, enabling attention to be focused on defining median values and more appropriate distributions to describe these variables.

A regionally segmented national scale multimedia contaminant fate model for Canada with GIS data input and display

Regional scale mass balance models are valuable tools for describing the fate of chemicals in areas with defined and fairly homogeneous environmental characteristics and chemical use patterns. These models often show that contaminant inflows from outside the region of interest are significant compared with local emissions. This is most likely for persistent chemicals and those that are efficiently transported in air or water. As a result regional levels of environmental contamination are controlled by external factors and meaningful evaluation requires assessment of contaminant fate in neighboring regions. A linked set of regional models thus has the potential to describe quantitatively the impact of chemical emissions over a wider geographic scale with significant spatial differences in environmental characteristics and chemical use patterns. We describe here a national scale contaiminant fate model for Canada based on the existing 24-region ChemCAN model. The ecological regions, which were previously treated individually, are linked with flows of air and water deduced from GIS analysis to provide a comprehensive description of contaminant fate over the entire country, including long-range transport between regions. The model is applied to describe the national-scale fate of three chemicals in Canada, benzene, trichloroethene, and diethylhexyl phthalate, exploiting GIS analysis for interpretation and presentation of model results. Agreement between predicted multimedia environmental concentrations and measured values is satisfactory for all three chemicals. In total this work represents an initial attempt to address the different processes of both linking a regional model and using GIS as a tool for data analysis and management.

Evaluation and comparison of multimedia mass balance models of chemical fate: application of EUSES and ChemCAN to 68 chemicals in Japan

The European Union System for Evaluation of Substances (EUSES) and the ChemCAN chemical fate model are applied to describe the fate of 68 chemicals on two spatial scales in Japan. Emission information on the chemicals has been obtained from Japan's Pollutant Release and Transfer Registry and available monitoring data gathered from government reports. Environmental concentrations calculated by the two models for the four primary environmental media of air, water, soil and sediment agree within a factor of 3 for over 70% of the data, and within a factor of 10 for over 87% of the data. Reasons for certain large discrepancies are discussed. Concentrations calculated by the models are generally consistent with the lower range of concentrations that are observed in the environment. Agreement between modeled and observed concentrations is considerably improved by including an estimate of the advective input of chemicals in air from outside Japan. The agreement between the EUSES and ChemCAN models suggests that results of individual chemical assessments are not likely to be significantly affected by the choice of chemical fate model. Primary sources of discrepancy between modeled and observed concentrations are believed to be uncertainties in emission rates, degradation half-lives, and the lack of data on advective inflow of contaminants in air.

On the validity of classifying chemicals for persistence, bioaccumulation, toxicity, and potential for long-range transport

It is argued that chemical substances can be meaningfully ranked or classified according to their persistence (P), bioaccumulation (B), toxicity (T), and potential for long-range transport (LRT) only if these attributes can be shown to be intensive, as distinct from extensive, properties of the substance, i.e., they are independent of quantity of substance. It is shown that P, B, and LRT can be considered intensive or quasi-intensive properties, but toxicity is more problematic. To obtain an intensive metric of toxicity requires selection of one of several possible extensive quantities that define exposure or dose. Ranking of a group of chemicals by toxicity is shown to be very dependent on which quantity is selected. It is suggested that toxicity metrics, such as lethal concentration to 50% of the population (LC50), lethal dose to 50% of the population (LD50), and threshold limit value (TLV) suffer the severe disadvantage of being dependent on the efficiency of delivery of the substance to the site(s) of toxic action in the organism. The use of measured or calculated internal dose is a preferable measure of toxicity since it reduces ambiguities inherent in the other metrics. Also, the primary concern is not the quasi-intensive property of toxicity; rather, it is the risk of toxic effects, an extensive quantity. To adequately assess the risk of toxic effects, both the toxic hazard and the degree of exposure must be characterized. Since exposure cannot be estimated without knowledge of the emission rate of chemicals to the environment, a compelling case can be made that screening to identify priority P, B, T, and LRT substances should be expanded to include quantity released to the environment as an additional factor.

An exploratory study of clinical decision-making in five countries

PURPOSE

To identify the cognitive processes nurses use in their decision-making in long- and short-term care settings in five countries, and the demographic variables associated with their decision-making. METHOD AND SAMPLES: The instrument used was a 56-item questionnaire that has been shown to be reliable in earlier studies. The sample consisted of five convenience samples of registered nurses working in either geriatric wards (n = 236) or acute medical-surgical wards (n = 223) in hospitals or nursing homes in Canada, Finland, Sweden, Switzerland, and the United States.

FINDINGS

Five models of decision-making were identified on the basis of factor analysis. They represent both analytical and intuitive cognitive processes. Analytical cognitive processes were emphasized in information collection, problem definition, and planning of care, and intuitive cognitive processes were emphasized in planning, implementing, and evaluating care. Professional education, practical experience, field of practice, and type of knowledge were significantly associated with decision-making models as well as with country of residence of the participants. The highest proportion of analytically oriented decision-makers was found among nurses in long-term care, the decision-making of nurses in short-term care was more intuitively oriented.

CONCLUSIONS

The results indicate that decision-making of participants varied from country to country and in different nursing situations. Future research should be focused on reasons for these differences, the relationship between the task and the nurses' type of knowledge, and how nurses use their knowledge to make decisions in different nursing situations.

The control of body orientation and center of mass location under asymmetrical loading

This study examined how whole body center of mass (COM) in the medial-lateral direction and spatial orientation of body segments changed during quiet stance when a weight was loaded on asymmetrically on the right side of the pelvis. The load corresponded to 10 and 30% of body weight (BW) of each individual subject, and the stance width was varied from narrow (7.6 cm) to normal (20 cm) and to wide (33 cm). A total of 10 healthy young subjects (18-30 years of age) participated in the study. The results indicated that the COM location was significantly shifted towards the loaded side (about 1.2 cm with a 10% BW load and 3 cm with a 30% BW load). In addition, COM was closer to the center with a narrow stance (0.38 cm to the right of the center) than both normal and wide stance (about 1 cm to the right). However, the COM shifts for all test conditions were smaller (<50%) than that of the theoretically predicted values. The smaller shift in COM position appeared to be mostly due to the change in spatial orientation of the pelvis and lower extremity (about 2.5 degrees change with a 10% BW load, and 4.5 degrees change with a 30% BW load), while maintaining the upper body orientation relatively unchanged (less than 2 degrees with a 30% BW load). This strategy may allow increased stability of the upright stance with minimal amount of muscle activation.

BETR North America: a regionally segmented multimedia contaminant fate model for North America

We present the Berkeley-Trent North American contaminant fate model (BETR North America), a regionally segmented multimedia contaminant fate model based on the fugacity concept. The model is built on a framework that links contaminant fate models of individual regions, and is generally applicable to large, spatially heterogeneous areas. The North American environment is modeled as 24 ecological regions, within each region contaminant fate is described using a 7 compartment multimedia fugacity model including a vertically segmented atmosphere, freshwater, freshwater sediment, soil, coastal water and vegetation compartments. Inter-regional transport of contaminants in the atmosphere, freshwater and coastal water is described using a database of hydrological and meteorological data compiled with Geographical Information Systems (GIS) techniques. Steady-state and dynamic solutions to the 168 mass balance equations that make up the linked model for North America are discussed, and an illustrative case study of toxaphene transport from the southern United States to the Great Lakes Basin is presented. Regionally segmented models such as BETR North America can provide a critical link between evaluative models of long-range transport potential and contaminant concentrations observed in remote regions. The continent-scale mass balance calculated by the model provides a sound basis for evaluating long-range transport potential of organic pollutants, and formulation of continent-scale management and regulatory strategies for chemicals.

Development of continental scale multimedia contaminant fate models: integrating GIS

The incentives and approaches for modelling chemical fate at a continental scale are discussed and reviewed. It is suggested that a multi-media model consisting of some 20-30 regions, each of which contains typically seven environmental compartments represents a reasonable compromise between the issues of the need for detailed resolution, avoidance of excessive data demands and inherent complexity and transparency. Strategies adopted in compiling the Berkley-Trent (BETR) model for North America are discussed and used to illustrate the issues of selecting appropriate number and nature of segments, treatment of air and water flows and the acquisition of environmental data. It is suggested that GIS software can play a valuable role in gathering and processing such data and in the display and interpretation of the results of the model assessment. The BETR model will be a useful tool for describing the nature of persistence and long-range transport of chemicals of concern in the North American environment.

First Report of Plum Pox Potyvirus in Ontario, Canada

Plum pox potyvirus (PPV) causes plum pox (sharka) disease, which is considered the most serious disease of stone fruits including peach, plum, nectarine, and apricot (2). The disease may cause losses as high as 80 to 100% of some crops (2). A survey was initiated in the Niagara region of Ontario, Canada, after it was reported that PPV was detected in Pennsylvania (1). The initial survey focused on Prunus material imported into Canada from the Pennsylvania region. Where imported trees could be identified, every tree was sampled. In cases where the imported trees were growing in mixed blocks with plants from other sources, 25% of the trees were sampled and tested as composites of four trees. PPV was detected in three symptomless Fantasia nectarine (Prunus persica var. nectarina) trees by triple-antibody sandwich (TAS) ELISA using the REAL Durviz kit (Valencia, Spain), which contains the universal PPV monoclonal 5B. PPV infection was confirmed by western blot analyses (a PPV polyclonal antibody and PPV 5B monoclonal were used as primary antibodies), reverse transcription polymerase chain reaction (RT-PCR), and TC/RT-PCR. In western blot analyses, the coat protein subunit sizes of the Canadian PPV isolates were estimated at 32 kDa based on electrophoretic mobility in 12% SDS-PAGE. RFLP analysis of the 243-bp fragment amplified using PPV specific primers P1 and P2 (4) indicated the presence of RsaI and AluI enzyme restriction sites, which is characteristic of PPV D strains. In RT-PCR analysis using D and M specific primers (3), only the D specific primers amplified a fragment 198 bp in size. This data provided conclusive evidence that the PPV isolates detected in Canada were PPV D, similar to the strain detected in Pennsylvania. The survey is continuing and is being expanded to determine the extent of spread and the exact distribution of the virus. References: (1) L. Levy et al. Phytopathology (Abstr.) 90:46, 2000. (2) M. Nemeth. Virus, Mycoplasma, and Rickettsia Diseases of Fruit Trees. Akademiai Kiado, Budapest. (3) A. Olmos et al. J. Virol. Methods 68:127-137, 1997. (4) T. Wetzel et al. J. Virol. Methods 33:355-365, 1991.

Transfer of the latissimus dorsi muscle after failed repair of a massive tear of the rotator cuff. A two to five-year review

INTRODUCTION

Seventeen patients with an average age of fifty-five years (range, thirty-two to seventy-seven years) who had ongoing pain and impaired function following failed operative treatment of a massive tear of the rotator cuff were managed with a transfer of the latissimus dorsi muscle as a salvage operation.

METHODS

The patients were examined at an average of fifty-one months (range, twenty-four to seventy-two months) after the operation. Pain, function, and satisfaction were assessed with use of a questionnaire, visual analog and ordinal scales, physical examination, and the University of California at Los Angeles shoulder score.

RESULTS

Fourteen of the seventeen patients were found to have significant relief of pain (p<0.0001) and a significant improvement in function (p<0.001 for all activities except lifting more than fifteen pounds [6.8 kilograms], for which the p value was <0.0036) and were satisfied with the result of the operative procedure. Fifteen patients stated that they would have the operative procedure again under similar circumstances. Seven of eight patients with a detached or nonfunctional anterior portion of the deltoid had substantial improvement. Three operations were classified as failures because the patients were not satisfied with the result and had ongoing pain and impaired function. All three failures were in patients who had a work-related injury. Overall, six patients had a work-related injury, and only three of them had a satisfactory result. There were three complications, all related to contracture of a hypertrophic axillary scar.

CONCLUSIONS

The results in this series indicate that transfer of the latissimus dorsi muscle is a reasonable approach for salvage after failed operative treatment of a massive tear of the rotator cuff.

An assessment of the environmental fate and exposure of benzene and the chlorobenzenes in Canada

Systematic modelling of the fate of benzene and the chlorobenzenes is presented which follows a four-stage process of chemical classification, quantifying discharge rates and environmental concentrations, evaluative assessment of fate and regional mass balance modelling has been carried out for the southern Ontario region. The EQC model was applied to determine the principal transport and transformation processes experienced by this group of chemicals, which vary considerably in volatility and hydrophobicity. Observed environmental concentrations are in satisfactory agreement with the predictions of the steady state Level III ChemCAN model of chemical fate. A multiple pathway human exposure model which estimates intake of contaminants by residents of southern Ontario has been developed and applied to these chemicals. A novel method of deducing maximum tolerable environmental concentrations is presented. Results suggest that benzene and 1,4-dichlorobenzene are present in the environment at levels sufficient to cause exposures near allowable daily intake (ADI) levels for the general population, but the other substances are present at levels which result in exposure ranging from 1/10 to 1/1000 of the ADI.

Issues for nurses in rural and remote Canada

Canada is a vast country with great diversity in its landscape, industry, culture and communities. The healthcare issues and concerns of people living in rural and remote areas are as fully diverse as the people and the landscape. This article describes the context of rural and remote nursing practice in Canada and discusses issues of health status and the social determinants of health, geographical isolation, professional isolation and cultural safety. It concludes with current initiatives in practice, education, research and policy. Particular issues facing nurses in rural and remote First Nations communities are highlighted.

'Being there': learning through active participation

Students engagement in learning is predicated not only on interest but on the perception of relevance to their needs. A hermeneutic interpretation of narrative student evaluation data from an introduction to nursing lecture course that was taught by means of a practice-based phenomenological approach revealed a pattern of student learning in which students moved from detachment to active participation in their learning. The stories shared by nurses in the practice setting were instrumental in introducing students to the world of nursing and facilitating a sense of belonging. Once engaged in the experience, students looked for opportunities to become active participants in their learning. A practice-based phenomenological approach to a theory course maximizes opportunities for student participation. Active reflection and integration allow students to make their own connections between theory and practice.

Decision making of nurses practicing in intensive care in Canada, Finland, Northern Ireland, Switzerland, and the United States

In this study, our intention was to describe the decision making of nurses practicing in intensive care, and the differences of nurses' decision making in Canada, Finland, Northern Ireland, Switzerland, and the United States. The instrument used in the study was a 56-item Likert-type questionnaire that has been used in previous studies and has proved to be a reliable tool. The target group comprised a nonrandom sample of nurses (N = 314) from five countries. The samples are not representative; therefore, the results in these cases cannot be generalized. The results showed that the decision making of nurses practicing in intensive care was broadly based, and that there were some country differences in data collection, problem definition, and planning. In contrast, decision making related to the implementation and evaluation of nursing is quite similar in the different countries. Canada and the United States on the one hand, and Finland, Northern Ireland, and Switzerland on the other, showed more similarities with each other in data collection, problem definition, and nursing planning related to decision making. Neither experience nor nurse's knowledge structure was associated with different decision-making approaches.

Evaluation of pelvic fractures. Clinical and radiologic

This article gives the orthopedic surgeon a framework to use during the initial evaluation of a patient with a pelvic fracture in the emergency room. The essential elements of the assessment of instability, both clinically and radiologically, are given in this article. Examples of the major patterns of instability are provided.

A phase I study of combined radiation therapy with 5-fluorouracil and low dose folinic acid in patients with locally advanced pancreatic or biliary carcinoma

PURPOSE

To evaluate the toxicities of a Phase I study of radiation therapy with concurrent 5-fluorouracil (5FU) and low dose folinic acid in patients with locally advanced pancreatic or biliary carcinoma.

METHODS AND MATERIALS

Twenty-seven patients with locally advanced carcinoma of the pancreas (n = 19), bile duct (n = 7), and gall bladder (n = 1) were entered into a Phase I study of combined radiation therapy, 5FU, and folinic acid. Radiation was given as a split course of 40 Gy in 20 daily fractions with a gap of 2 weeks after 20 Gy. 5-Fluorouracil, 300 to 375 mg/m2/day and folinic acid, 20 mg/m2/day were given as an i.v. bolus daily for 5 days beginning on day 1 and again on day 29.

RESULTS

Eight patients developed Grade 3 or 4 toxicities (National Cancer Institute common toxicity criteria) including nausea and vomiting (n = 4), oral mucositis (n = 4), myelosuppression (n = 2), infection (n = 2), and diarrhea (n = 1). Four patients did not complete the planned protocol due to treatment toxicities. There were two treatment deaths secondary to septic neutropenia. Treatment toxicity appeared to be related to age (> 70), performance status (ECOG = 2), and 5FU dose (> 350 mg/m2/day).

CONCLUSION

This protocol is poorly tolerated by elderly patients or those with poor performance status, and 350 mg/m2/day is our recommended dose for 5FU as given in this protocol.

Psychosocial adjustment in children with port-wine stains and prominent ears

OBJECTIVE

To evaluate psychosocial adjustment in children with port-wine stain (PWS) and children with prominent ears (PE).

METHOD

Thirty-two children aged 7 to 16 years with facial PWS and 42 children with PE were evaluated using the Harter Self-Perception Profile, the Revised Children's Manifest Anxiety Scale, the Children's Depression Inventory, the Disfigurement Perception Scale, and the Child Behavior Checklist. Results were compared with normative data for the local population or with a control group. Profile scores were correlated with severity of the PWS or prominence of the ears.

RESULTS

Children with PE had poorer self-perception, higher concentration anxiety, and more internalizing and externalizing symptoms, and they were more withdrawn and had more social problems than children with PWS. The children with PWS functioned as well as or better than nondisfigured peers on measurements of psychosocial adjustment, while children with PE scored lower than nondisfigured peers on measures of self-perception and parent-rated social and attention problems. There was no correlation between degree of disfigurement and level of psychosocial adjustment.

CONCLUSIONS

Psychosocial adjustment varied according to the nature of the disfigurement or deformity and was unrelated to the severity of the disfigurement.

Renal artery stenosis managed by Palmaz stent insertion: technical and clinical outcome

OBJECTIVE

To assess the technical and clinical outcome of Palmaz renal artery stent insertion in patients with renal artery stenosis.

DESIGN

Twenty-nine patients with radiological evidence of renal artery stenosis and hypertension (16 patients, mean +/- SD diastolic blood pressure 100.5 +/- 8.16 mmHg) and/or renal impairment (17 patients, mean +/- SD serum creatinine 376 +/- 169 mu mol/l) were referred for radiological intervention. Of these, 22 had ostial atheromatous lesions, six had atheromatous non-ostial lesions and one patient had fibromuscular dysplasia. Palmaz stent insertion was performed where either previous or concomitant percutaneous transluminal renal angioplasty (PTRA) had been unsuccessful. Technical success was defined primarily as <30% residual stenosis. A prospective radiological and clinical follow-up was performed and the results compared with the outcome following PTRA alone in a similar group of patients from our centre.

RESULTS

Immediate technical success was achieved in all 29 patients. Follow-up angiography in 24 patients after a mean of 7 months showed restenosis in four patients. The hypertension was not 'cured' in any patient; a blood pressure fall was observed in seven patients (44%) and no change in the remaining nine subjects (56%). Renal function improved in four patients (24%), two of whom had angiotensin converting enzyme inhibitor-exacerbated renal impairment. This compares with an immediate technical success of 81% for PTRA alone, with cure in 50% and improvement in 32% of patients with hypertension and improvement in renal function in 64.7% of patients with renal impairment.

CONCLUSIONS

Palmaz renal artery stent insertion has a higher technical success rate than PTRA, but the clinical improvement is disappointing in our patient population.

'It's the little things that count': the hidden complexity of everyday clinical nursing practice

This article reports on one aspect of a phenomenological study of everyday experience in nursing and how it contributes to the development of nursing expertise. The study was carried out with 10 'excellent, experienced' surgical ward sisters in two Scottish teaching hospitals. The ward sisters were found to help individual patients towards recovery by making the ward work for all. When moment-by-moment nursing practice, the context of nursing experience, is examined, it is found to be patient-centred and complex, geared towards multilayered goals. Three distinct yet inextricably intertwined processes--noticing, understanding and acting--characterize how nurses practise nursing. The quality of these processes contributes to the effectiveness of nurses' caring practices. The 'little things' of nursing practice make a difference to patients because they are imbued with nursing knowledge and skill.