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Assessments of aggregate exposure to pesticides and other surface contamination in residential environments are often driven by assumptions about dermal contacts. Accurately predicting cumulative doses from realistic skin contact ...
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Assessments of aggregate exposure to pesticides and other surface contamination in residential environments are often driven by assumptions about dermal contacts. Accurately predicting cumulative doses from realistic skin contact scenarios requires characterization of exposure scenarios, skin surface loading and unloading rates, and contaminant movement through the epidermis. In this article we (1) develop and test a finite-difference model of contaminant transport through the epidermis; (2) develop archetypal exposure scenarios based on behavioral data to estimate characteristic loading and unloading rates; and (3) quantify 24-hour accumulation below the epidermis by applying a Monte Carlo simulation of these archetypal exposure scenarios. The numerical model, called Transient Transport through the epiDERMis (TTDERM), allows us to account for variable exposure times and time between exposures, temporal and spatial variations in skin and compound properties, and uncertainty in model parameters. Using TTDERM we investigate the use of a macro-activity parameter (cumulative contact time) for predicting daily (24-hour) integrated uptake of pesticides during complex exposure scenarios. For characteristic child behaviors and hand loading and unloading rates, we find that a power law represents the relationship between cumulative contact time and cumulative mass transport through the skin. With almost no loss of reliability, this simple relationship can be used in place of the more complex micro-activity simulations that require activity data on one- to five-minute intervals. The methods developed in this study can be used to guide dermal exposure model refinements and exposure measurement study design.
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The risks related to the use of essential oils are difficult to ascertain at present, due in part to the large number of different oils available on the market, making it difficult for the risk assessor. Essential oils may contain...
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The risks related to the use of essential oils are difficult to ascertain at present, due in part to the large number of different oils available on the market, making it difficult for the risk assessor. Essential oils may contain skin allergens in significant amounts, and could thus pose a risk to the consumer. The aim of our study was to collect as much qualitative and quantitative data as possible on allergens present in essential oils. 11 types of essential oils, with 25 respective subspecies, were taken into account based on a previous survey. Based on the literature, 517 dosages were recorded from 112 publications, providing precious information for probabilistic exposure assessment purposes. 22 substances recognized as established allergens were found in the essential oils we included. Of these, 11 are also found in cosmetics as fragrance components. These results are of major importance regarding co-exposure to fragrance allergens. Moreover, this could lead to regulatory measures for essential oils in the future, as it is the case for cosmetic products, in order to better protect consumers against skin allergy. (C) 2016 Elsevier Inc. All rights reserved.
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Summary Background Information on the presence of contact allergens and irritants is crucial for the diagnosis of occupational contact dermatitis. Ingredient lists and Material Safety DataSheets (MSDSs) may be incomplete. Objectiv...
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Summary Background Information on the presence of contact allergens and irritants is crucial for the diagnosis of occupational contact dermatitis. Ingredient lists and Material Safety DataSheets (MSDSs) may be incomplete. Objectives To evaluate the workability of a systematic exposure assessment in consecutive patients with suspected occupational contact dermatitis, and to study how it could potentially aid correct diagnostic classification. Methods A tool for systematic stepwise assessment of exposures in the work environment was developed, consisting of six steps spanning medical history and workplace visits. The programme included 228 consecutive patients diagnosed with occupational contact dermatitis; all patients underwent a clinical examination, the stepwise exposure assessment, and extensive patch and prick testing. Results Of the participants, 48.2% were classified as having occupational allergic contact dermatitis. The diagnosis was made at the stepwise exposure assessment for 50.0% of patients at Step 1 (medical history) and for 34.5% at Step 2 (ingredient labelling/MSDS). We found 132 different occupational allergens of relevance to the patients' eczema, of these, 78.0% were allergens not included in the European baseline series. Conclusions Systematic stepwise exposure assessment provides information that results in the identification of occupational allergies caused by allergens not included in the European baseline series in a substantial number of patients.
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This study aimed to further refine the exposure assessment of migrants from food-contact materials by characterizing, at the household level, food packaging usage (amount and type) in Portuguese urban families. Packages from domes...
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This study aimed to further refine the exposure assessment of migrants from food-contact materials by characterizing, at the household level, food packaging usage (amount and type) in Portuguese urban families. Packages from domestic use were collected from a sample of 105 consumers from 34 households over a 30-day period. Collected packages (more than 6000 items) were characterized in the laboratory and data were used to estimate: (i) global packaging usage and food intake; (ii) the consumption factors (CF) that describe the fraction of the daily diet expected to be in contact with specific packaging materials and (iii) the food-type factors (FTF) that reflect the fraction of all food contacting each material which differ in nature according to six major types: aqueous, acidic, alcoholic, milky, fatty and dry. The daily intake of packaged food and beverages consumed at home ranged from 5-50 g kg~(-1)bw. Considering all materials, total package usage ranged from 0.1 to 0.6 dm~2 day~(-1) kg~(-1) bw. The ratio between package surface area in contact and the quantity of food was determined for all packaging items collected and an average value of 25 dm~2 kg~(-1) food was recorded. Data were gathered and presented in a manner compatible with current probabilistic approaches to exposure assessment. In this way, relevant consumption patterns from this type of population can be best represented in exposure assessments and subsequent risk assessments.
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Background. Predictors of latent tuberculosis infection (LTBI) among close contacts of persons with infectious tuberculosis (TB) are incompletely understood, particularly the number of exposure hours.
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Abstract The increasing use of new radiopharmaceuticals invites us to reconsider some radiation protection issues, such as the contact restriction time that limits public exposure by nuclear medicine patients. Contact restriction ...
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Abstract The increasing use of new radiopharmaceuticals invites us to reconsider some radiation protection issues, such as the contact restriction time that limits public exposure by nuclear medicine patients. Contact restriction time should be patient specific and conservative, and its assessment made easy for clinicians. Here a method is proposed based on conservative estimation of the whole-body retention function and at least one measurement of the patient’s dose rate. Recommended values of the retention function are given for eight therapies: 131I (Graves’ disease, remnant ablation, patient follow-up, meta-iodobenzylguanidine), 177Lu-prostate-specific membrane antigen and 177Lu-DOTATATE therapies, and 90Y and 166Ho microsphere injection of the liver. The patient line source model for scaling dose rate from one distance to another is included in the restriction time calculation. The method is benchmarked against published values and the influence of the dose rate scaling and whole-body retention function illustrated. A spreadsheet is provided, along with the source code, with recommended values for the eight therapies. The recommended values can be changed as well as the dose rate scaling function, and other radiopharmaceuticals can be included in the spreadsheet provided retention functions are defined.
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Eisenia fetida earthworms were exposed to sub-lethal levels of imidacloprid for 48h via contact filter paper tests and soil tests. After the exposure, H-1 nuclear magnetic resonance (NMR) metabolomics was used to measure earthworm...
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Eisenia fetida earthworms were exposed to sub-lethal levels of imidacloprid for 48h via contact filter paper tests and soil tests. After the exposure, H-1 nuclear magnetic resonance (NMR) metabolomics was used to measure earthworm sub-lethal responses by analyzing the changes in the polar metabolite profile. Maltose, glucose, malate, lactate/threonine, myo-inositol, glutamate, arginine, lysine, tyrosine, leucine, and phenylalanine relative concentrations were altered with imidacloprid exposure in soil. In addition to these metabolites (excluding leucine and phenylalanine), fumarate, ATP, inosine, betaine, scyllo-inositol, glutamine, valine, tryptophan, alanine, tyrosine, and isoleucine relative concentrations shifted with imidacloprid exposure during contact tests. Metabolite changes in E. fetida earthworms exposed to imidacloprid showed a non-linear concentration response and an upregulation in gluconeogenesis. Overall, imidacloprid exposure in soil induces a less pronounced response in metabolites glucose, maltose, fumarate, adenosine-5-triphosphate (ATP), inosine, scyllo-inositol, lactate/threonine, and tyrosine in comparison to the response observed via contact tests. Thus, our study highlights that tests in soil can result in a different metabolic response in E. fetida and demonstrates the importance of different modes of exposure and the extent of metabolic perturbation in earthworms. Our study also emphasizes the underlying metabolic disruption of earthworms after acute sub-lethal exposure to imidacloprid. These observations should be further examined in different soil types to assess the sub-lethal toxicity of imidacloprid to soil-dwelling earthworms.
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The European Union approach to assessing exposure to chemical migrants from plastic food-contact materials has been to assume an intake of 1 kg of food in contact with a particular material, per 60 kg person per day, which equates...
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The European Union approach to assessing exposure to chemical migrants from plastic food-contact materials has been to assume an intake of 1 kg of food in contact with a particular material, per 60 kg person per day, which equates to 16.7g kg~(-1) body weight. A food packaging surface area-food mass ratio of 6dm~2/1 kg is assumed, equivalent to 0.1 dm~2 kg~(-1) of body weight. Children might be at increased risk to exposure from migrants as they have higher intakes of food per kg body weight compared with adults. In addition, much of the food marketed for/to children is in small portions and therefore the food-contact material area-food mass ratio is relatively high. To determine if, and how, the European Union model might be modified to ensure specific protection against chemical migration into food marketed for children, data on 4-day food intakes of 297 children aged 0-6 years were collected including information on pack size, pack type and food-contact material area-food mass ratio. The 297 children consumed a total of 1646 kg of food and drink (including tap water), of which 978 kg (59%) was packaged with 67% of this packaged in plastics. Mean intakes of food packaged in plastic ranged from 27 g kg~(-1) body weight (for the infants under 1 year) to 51 g kg~(-1) body weight (for the 1-4-year-olds). This was higher than the 16.7 g kg~(-1) body weight derived from the European Union convention. The mean area of packaging in contact with the food consumed daily per kg body weight were 0.65 dm~2 kg~(-1) for the infants under 1 year, 0.81 dm~2kg~(-1) for the 1-4-year-olds, and 0.66dm~2kg~(-1) for the 4-6-year-olds. All 297 children had intakes that exceeded 0.1 dm~2 of packaging per kg of body weight assumption.
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Hypersensitivity reactions are not uncommon, with an estimated 15% of the world’s population affected by a type of allergic reaction during their lifetime. Contact dermatitis is an inflammatory skin disorder that can present as a...
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Hypersensitivity reactions are not uncommon, with an estimated 15% of the world’s population affected by a type of allergic reaction during their lifetime. Contact dermatitis is an inflammatory skin disorder that can present as an acute, subacute or chronic condition. It is estimated that 20% of the European population has a contact allergy to at least a single allergen. Contact dermatitis affects female twice as frequently as male patients3 and often starts at a young age, with a prevalence of 15% in 12-16-year-olds. In healthcare workers, contact dermatitis is the most common form of work related skin disease and 1,000 nurses develop this condition each year in the UK.5 The Health and Safety Executive highlighted dental nurses, dentists and general nurses as being at high risk for contact dermatitis in healthcare. There are two main types of contact dermatitis. Irritant contact dermatitis accounts for approximately 80% of reported contact dermatitis cases while allergic contact dermatitis (ACD) has a prevalence of approximately 20%. ACD is a type IV hypersensitivity reaction that predominantly affects the hands, causing pruritus, burning and stinging, with indurated papules and bullae formation in severe cases. Chronic ACD can also present with scaling and fissuring. ACD affects 22-43% of dental professionals globally and occupational contact dermatitis (OCD) is the most common occupational skin disease, accounting for 70-90% of all reported cases.
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