L1 is a major and highly immunogenic protein component of human granulocytes. It was purified from random samples of blood‐donor leukocytes. An antiserum to L1 was initially raised in rabbits by immunization with protein fractions from preparative agarose gel electrophoresis. The main problem in purifying L1 was its poor stability when carried through multiple steps. Preparative isoelectric focussing was therefore adopted as an efficient one‐step method. The isoelectric focussing pattern of L1 was greatly influenced by the presence of EDTA or calcium ions in the sample buffer. With low EDTA concentrations or calcium excess, L1 focussed as seven protein bands in two regions, pH 6.1–6.5 and pH 7.6–8.4. Conversely, L1 was found only in the pH‐6.1–6.5 region when excess EDTA was added to the sample. Irrespective of conditions, the bulk of L1 focussed at pH 6.3 and pH 6.5. Also the electrophoretic mobility of L1 was strongly influenced by calcium ions, suggesting uptake of calcium by the protein. In the presence of calcium, L1 adhered to glass surfaces and filters used for concentration of protein solutions. The latter problem could be prevented by addition of EDTA. The molecular mass of L1 was determined to be about 36.5 kDa. The molecule was shown to consist of three non‐covalently linked 12.5‐kDa subunits.
Abstract Subjective symptoms and exposure to organic compounds were recorded in road repair and construction workers. Abnormal fatigue, reduced appetite, laryngeal/pharyngeal irritation, and eye irritation were recorded more often in such workers handling asphalt than in a corresponding reference group without asphalt exposure. Mean daily exposure to volatile compounds was only occasionally above 1 ppm. Mean exposure to asphalt fume was 0.358 mg/m 3 . There was no correlation between symptoms and total amount of volatile compounds, but a significant positive correlation was demonstrated between symptoms and some substances. The highest correlation was found for 1, 2, 4 trimethyl benzene. Symptoms increased with increasing asphalt temperature and with increasing concentrations of asphalt fumes. Amine addition did not increase the sum of symptoms, but soft asphalt seems to result in fewer symptoms than the harder types. Symptoms were not related to external factors like weather, traffic density, or specific working operations. As preventive measures, asphalt temperature should be kept below 150°C, fume concentrations below 0.40 mg/m 3 , and if possible, the use of harder asphalt types which also require high temperatures should be avoided.
