The elicitation response in allergic contact dermatitis for the hair dye substance p-phenylenediamine (PPD) is dose dependent,but threshold concentrations have not previously been investigated. 15 PPD-sensitive patien...The elicitation response in allergic contact dermatitis for the hair dye substance p-phenylenediamine (PPD) is dose dependent,but threshold concentrations have not previously been investigated. 15 PPD-sensitive patients participated in a serial dilution 48-hr patch test with PPD using 8 concentrations of PPD ranging from 1 to 10 000 on the upper back. Petrolatum was applied as control. Three concentrations (50, 100 and 500 p.p.m. PPD) were also applied to the retroauricular area and on the lateral aspects of the upper arms. 14 of the 15 participants reacted to one or more of the test samples. The threshold value for 10%of the tested persons (ED10) based on+or stronger reactions for PPD on the back was 38 p.p.m. (CI:4.3-100). There were no statistically significant differences in the sensitivity of the three anatomical regions. The upper back is a suitable region for patch testing patients with hair dye dermatitis.展开更多
The tested soils containing different Cd levels were obtained by mixing the normal cultivated soils with the Cd-contaminated soils taken from the paddies near a mine. Five major categories of vegetables, i.e. cucumber...The tested soils containing different Cd levels were obtained by mixing the normal cultivated soils with the Cd-contaminated soils taken from the paddies near a mine. Five major categories of vegetables, i.e. cucumber, cowpea, Bok choy, radish and lettuce, widely planted in the spring and autumn in Hunan Province, were selected for pool-culture experiments. Results showed that the Cd accumulations varied greatly according to the category of vegetables. The Cd accumulations in cucumber and cowpea growing in soils with high Cd levels (1.5 mg/kg) were within the threshold limits of the national standards, meaning that these two categories are safe to grow in Cd-contaminated soils. For either the cucumber or the cowpea category, there were no significant differences in the Cd accumulations of different genotypes. Most of the tested Bok choy and radish cultivars could grow safely in soils whose Cd levels were below 1.0 mg/kg. In comparison, the Cd accumulations in some cultivars tended to increase sharply as the Cd level in the soil went beyond 1.0 mg/kg. Significant variations were also observed in the Cd accumulations of different genotypes with mounting Cd levels in the soil. Besides, there were no positive correlations between Cd accumulations in plants and Cd levels in soils, indicating large fluctuations and poor ecological stability of Bok choy and radish. Therefore, the planting of Bok choy and radish should be strictly evaluated and controlled in Cdcontaminated regions. The Cd contents of most celtuce cultivars growing in mildlycontaminated soils had already exceeded the threshold limit. Therefore, it is not safe for celtuce to grow in Cd-contaminated environments.展开更多
文摘The elicitation response in allergic contact dermatitis for the hair dye substance p-phenylenediamine (PPD) is dose dependent,but threshold concentrations have not previously been investigated. 15 PPD-sensitive patients participated in a serial dilution 48-hr patch test with PPD using 8 concentrations of PPD ranging from 1 to 10 000 on the upper back. Petrolatum was applied as control. Three concentrations (50, 100 and 500 p.p.m. PPD) were also applied to the retroauricular area and on the lateral aspects of the upper arms. 14 of the 15 participants reacted to one or more of the test samples. The threshold value for 10%of the tested persons (ED10) based on+or stronger reactions for PPD on the back was 38 p.p.m. (CI:4.3-100). There were no statistically significant differences in the sensitivity of the three anatomical regions. The upper back is a suitable region for patch testing patients with hair dye dermatitis.
文摘The tested soils containing different Cd levels were obtained by mixing the normal cultivated soils with the Cd-contaminated soils taken from the paddies near a mine. Five major categories of vegetables, i.e. cucumber, cowpea, Bok choy, radish and lettuce, widely planted in the spring and autumn in Hunan Province, were selected for pool-culture experiments. Results showed that the Cd accumulations varied greatly according to the category of vegetables. The Cd accumulations in cucumber and cowpea growing in soils with high Cd levels (1.5 mg/kg) were within the threshold limits of the national standards, meaning that these two categories are safe to grow in Cd-contaminated soils. For either the cucumber or the cowpea category, there were no significant differences in the Cd accumulations of different genotypes. Most of the tested Bok choy and radish cultivars could grow safely in soils whose Cd levels were below 1.0 mg/kg. In comparison, the Cd accumulations in some cultivars tended to increase sharply as the Cd level in the soil went beyond 1.0 mg/kg. Significant variations were also observed in the Cd accumulations of different genotypes with mounting Cd levels in the soil. Besides, there were no positive correlations between Cd accumulations in plants and Cd levels in soils, indicating large fluctuations and poor ecological stability of Bok choy and radish. Therefore, the planting of Bok choy and radish should be strictly evaluated and controlled in Cdcontaminated regions. The Cd contents of most celtuce cultivars growing in mildlycontaminated soils had already exceeded the threshold limit. Therefore, it is not safe for celtuce to grow in Cd-contaminated environments.
