Histamine-releasing activity and bronchoconstricting effects of sisal

Respiratory function and immunological reactions in sisal workers

A cross-sectional study of respiratory function was performed in 50 sisal textile workers in 1972. Twenty of the 50 sisal workers still employed in the sisal mill were reexamined 19 years later. At the time of the initial study there were higher prevalences of all chronic respiratory symptoms in sisal compared with control workers. By the time of the follow-up study a significant increase had occurred in almost all chronic respiratory symptoms among the 20 sisal workers. At the time of the initial study there were similar and statistically significant across-shift reductions of forced vital capacity (FVC) and the 1-s forced expiratory volume (FEV1) on Monday and the following Thursday of the work week. Across-shift reductions in FVC and FEV1 in the 20 sisal workers at the follow-up study were larger than at the first measurement. Two sisal workers out of 20 (10.0%) had a positive skin test reaction to an extract sisal; both related symptoms of occupational asthma. In two sisal workers (10.0%) increased IgE was measured; one of these had symptoms of occupational asthma. Our data suggest that exposure to sisal dust in the textile industry may, in some workers, cause the development of respiratory difficulties. Immunological testing may be of value in identifying such workers at risk for occupational asthma.

Lung function in sisal ropemakers

Lung function was measured by spirometry in 66 workers in a sisal ropemaking factory, and in their matched controls. The major atmospheric contaminant was the lubricant (or a component part thereof) used to soften the fibre. The concentration of airborne matter was generally less than 1 mug m--3. There was no difference in lung function between the two groups before the start of the working shift, that is, the mixture of softening lubricant and sisal caused no long-term effects. Although there was no change in lung function over the working shift in the group making sisal rope, the control group did show a significant increase in lung function over the same period. This suggests that an effect attributable to the lubricant and sisal dust did exist. In previous studies little mention has been made of the softeners used in the processing of sisal fibre. These additives may exert a significant effect on ventilatory capacity and may act in conjunction with sisal dust.

Histamine release from platelets for assay of byssinogenic substances in cotton mill dust and related materials

Previous reports suggest that byssinosis, an asthma-like condition among textile workers, may be mediated in part by histamine liberated following inhalation of dust. A simple, sensitive, and reliable procedure using pig platelets which contain the unusually high concentration of 0.8-1.6 microgram histamine/10(9) cells has been devised for the assay of histamine-releasing factors in cotton mill dust and related materials, and has yielded results generally in accordance with earlier assays using chopped lung tissue. As little as 50--100 microgram of total extractable substances from cotton mill dust can be measured. The activity of the extract is associated with the non-dialysable high molecular weight portion. However, conditions of acid hydrolysis do not destroy the activity. Extracts of leaves from different varieties of plant are highly potent, which suggests that the factors responsible for byssinosis are widely distributed plant components, present in textile fibre plants and converted to a respirable form by handling processes. Ellagic acid and sodium metasilicate release histamine from pig platelets, and represent new classes of compounds with possible roles in the aetiology of byssinosis.

Respiratory changes in two groups of flax workers with different exposure pattern

Zuskin, E., and Valić, F. (1973).Thorax, 28, 579-583. Respiratory changes in two groups of flax workers with different exposure pattern. A high mean total concentration of flax particles (16·9 mg/m³), of which about 20% were of respirable size, caused a high prevalence of bysinosis (69·9%) in 55 non-smoking female workers exposed to biologically retted flax over an average period of 11 years. A significant mean FEV_1·0 decrease over the first work shift after the weekend break was recorded in both byssinotics and non-byssinotics but was more pronounced in the former. The mean acute FEV_1·0 reductions over a work shift were smaller on the third than on the first day in the week.

Significant decreases in FEV_1·0 and in maximum expiratory flow rate at 50% of vital capacity over the Monday work shift were recorded in a group of 17 seasonal male workers who had been exposed to flax for only two to three months each year for no more than three years.

A high prevalence of chronic cough, chronic sputum production, and chronic bronchitis was found in the female flax workers, especially among the byssinotics.