Potential exposure of amateurs (consumers) through painting wood preservative and antifoulant preparations.
(25/693)
Data are presented for work patterns, inhalation and potential dermal exposure for amateurs painting wood preservatives to garden structures, and antifoulants to leisure boats. The results are quoted as rates of in-use product deposition or time-weighted inhaled product concentrations. Quoting data in this general and normalized form enables predictive risk assessment. The product densities were assumed to be 1.0 gml(-1). Inhalation exposure was detected in about 40% of the surveys, being about 100 times higher for wood preservatives than for antifoulants. The maximum airborne wood preservative concentration was 8.03 mg m(-3), measured over the period of painting (that is not an 8h time-weighted average value). Regarding potential dermal exposure, the processes are only broadly comparable. Most of the data appear to fall into relatively narrow distributions, with median values around 5 mg min(-1) (for preservatives) and around 16 mg min(-1) (for antifoulants). About half of the deposit on clothing was found to occur below the waist. The data comparing gloved and bare hand working indicate that even simple gloves offer a degree of protection for skin. (+info)
Angiotensin-(1-7) increases osmotic water permeability in isolated toad skin.
(26/693)
Angiotensin-(1-7) (Ang-(1-7)) increased osmotic water permeability in the isolated toad skin, a tissue with functional properties similar to those of the distal mammalian nephron. Concentrations of 0.1 to 10 microM were effective, with a peak at 20 min. This effect was similar in magnitude to that of frog skin angiotensin II (Ang II) and oxytocin but lower than that of human Ang II and arginine-vasotocin. The AT2 angiotensin receptor antagonist PD 123319 (1.0 microM) fully inhibited the response to 0.1 microM Ang-(1-7) but had no effect on the response to Ang II at the same concentration. The specific receptor antagonist of Ang-(1-7), A-779, was ineffective in blocking the response to Ang-(1-7) and to frog skin Ang II. The AT1 receptor subtype antagonist losartan, which blocked the response to frog skin Ang II, was ineffective in blocking the response to Ang-(1-7). The present results support the view of an antidiuretic action of Ang-(1-7) in the mammalian nephron. (+info)
Fluorescence excitation spectroscopy provides information about human skin in vivo.
(27/693)
Fluorescence spectroscopy of human skin has the potential to provide useful morphologic and biochemical information. The endogenous fluorescence of human skin has been investigated in vivo on normal human volunteers as well as on patients with psoriasis and it was found that characteristic bands can be identified in the fluorescence spectra that are associated with specific skin fluorophores. One epidermal band (295 nm excitation, attributed to tryptophan) and two dermal bands (335 and 370 nm excitation, attributed to collagen cross-links) were consistently present in all fluorescence spectra. In addition, the fluorescence spectra obtained from lesions and nonlesional sites of psoriatic patients differed from those obtained from healthy volunteers and the hyperproliferative state of the lesions was characterized by a significantly larger signal at 295 nm excitation. These results indicate that fluorescence spectroscopy is a promising technique for the investigation of human skin in vivo. (+info)
Dermal in vitro penetration of methiocarb, paclobutrazol, and pirimicarb.
(28/693)
OBJECTIVES: The dominant route of occupational exposure to pesticides in horticulture is dermal. However, preventive measures are seldom used when handling plant cultures recently treated with pesticides, thus causing significant dermal exposure and potential absorption. Assessment of exposure often depends on biological monitoring of blood or urine samples. The skin often acts as a temporary reservoir for chemicals before absorption. Failure to consider the lag time between dermal exposure and appearance of pesticide or metabolites in the general circulation may lead to false conclusions about assessment of exposure. METHODS: In an experimental model in which in vitro static diffusion cells were mounted with human skin, dermal penetration of three extensively used pesticides (methiocarb, paclobutrazol, pirimicarb) was evaluated. RESULTS: Pirimicarb and paclobutrazol had comparable rates of dermal penetration and lag times of around 18 hours. Methiocarb had a considerably shorter lag time. Dermal penetration continued for extended periods after exposure had ended. CONCLUSIONS: With lag times sometimes considerably longer than a normal working day, biological monitoring at the end of exposure may seriously underestimate the actual exposure. There may be implications for regulatory guidelines, which often require only 24 hour observation periods. (+info)
Dermal exposure assessment.
(29/693)
Assessing dermal exposure is a complex task. Even the most commonly used methods face fundamental problems and there are large gaps in the documentation and validation of sampling methods. Still larger uncertainties exist regarding strategies for measurement. We propose a strategy based on a conceptual model and which draws on the considerable insight gained for airborne contaminants, including EN 689 for assessing exposure by inhalation. The vast amount of air sampling data has provided good insight into the statistical properties of short-term and long-term exposure levels, which is essential for designing cost-effective exposure studies. For surface and skin contaminants an understanding of the distribution types and parameter values is only beginning to emerge. Transport rates away from the skin contaminant layer determine the 'memory' of a dermal sample and measurement principles are proposed depending on these rates. It is argued that uptake is the ultimate dermal exposure metric for risk assessment and should be the basis for devising dermal occupational exposure limits. (+info)
Hand wash and manual skin wipes.
(30/693)
Hand wash and skin wipes are major techniques that have been used for dermal exposure sampling. Both techniques remove chemicals either deposited on or transferred to the skin contaminant layer by a combination of chemical and mechanical actions. The paper overviews identified methods and techniques, with emphasis on sampling parameters and sampling efficiency. It is concluded that identified sampling protocols, including sampling techniques, deviate at possible key issues, which hampers comparisons of study results. It is recommended to conduct sampling efficiency studies prior to field sampling, under conditions that are quite similar to conditions of exposure regarding exposure process, levels of skin loading, and time of residence of the compound on the skin. Harmonization of sampling protocols will be a first step in creating a database for better understanding the influence of sampling parameters on the performance of removal techniques to assess dermal exposure. (+info)
Use of patches and whole body sampling for the assessment of dermal exposure.
(31/693)
There has been a growing awareness of the importance of dermal exposure in recent years. A wide range of techniques are employed to measure exposure, of which surrogate skin techniques such as patch sampling and whole body sampling are frequently used. One of the problems associated with dermal sampling is that different methods often produce different results due to differences in the principles involved in sample collection. As a consequence little progress towards establishing dermal exposure limits has been made. Both patches and clothing act as passive samplers and are intended to collect all of a substance deposited on them. This paper details the principles underlying patch and whole body sampling and outlines some of the advantages and disadvantages of each. A conceptual model has recently been proposed for dermal exposure and the role that surrogate techniques may play in the application of this model is discussed. Finally, suggestions are made as to how these techniques may be made more relevant and areas of future research highlighted. (+info)
Use of qualitative and quantitative fluorescence techniques to assess dermal exposure.
(32/693)
Fluorescent tracers provide a way of simultaneously assessing the mass of a contaminant hazardous substance on the surface of the skin of a worker and the area of skin exposed. These parameters, along with the duration of exposure and the estimated contaminant concentration in the skin contamination layer, can be used to calculate the likely uptake through the skin. Repeated assessment of the mass of tracer on a surface within a room or on the surface of the skin can also allow the net transfer of contaminant to that compartment to be estimated. Qualitative evaluation of transfer processes using fluorescent tracers can help identify important secondary sources of exposure. (+info)