Exposure to cotton dust in an experimental cardroom.

Abstract

ABSTRACr Changes in respiratory function (FEV,) and polymorphonuclear neutrophils (PMN) on nasal epithelium were studied in 68 students and 39 cotton mill workers in an experimental cardroom. The exposure was characterised by the vertical elutriator dust and endotoxin levels. A dose related decrease was found for FEV, which was more pronounced in smoking workers. The thresholds for no FEV, reaction were 0-58 mg/i3 dust and 0*17 ,g/m3 endotoxin for students and 0-43 mg/m3 and 0.08 ug/m3 for smoking workers. (FEVy) and the number of Gram-negative bacteria in the processed cotton. 5 The effect has been related to bacterial lipopolysacchrides (endotoxin) present in the outer cell wall of Gram-negative bacteria.6 In some studies a larger reaction has been found among smokers compared with non-smokers at the same exposure levels.2To explore further the reactions among previously unexposed subjects and cotton mill workers after exposure to cotton dust studies were undertaken in an experimental cardroom where the dust level could be varied. Workers from cotton mills and students not previously exposed to cotton dust were used as test subjects. FEV, was measured before and after a four hour working session which for the cotton mill workers took place on a Monday. The number of polymorphonuclear leukocytes (PMN) in the nasal secretion was determined. Information on subjective symptoms such as chest tightness and fever was obtained from questionnaires.Received 10 January 1983. Accepted 11 July 1983 Material and methodsThe study was performed in an experimental cardroom measuring 6-4 x 5.3 x 2.8 m. A carding machine without a protective cover was situated in the middle of the room and cotton laps were processed. The dust levels in the room could be varied by adjusting the ventilation.In the experiments United States middle grade bale cotton was used. For some of the experiments washed cotton was prepared. The washing procedure consisted of flushing water over a web of cotton on a rayon manufacturing line whereafter the cotton was dried. The maximum temperature during the process was 66°C.The exposure in the cardroom was determined using three vertical elutriators7 placed on different sides of the carding machine. The filters collecting respirable dust were weighed on a semimicro balance (Sartorius 2474) using an alpha-radiating source to prevent static electricity. The mean value from two or three filters was calculated and expressed as mg/i3.After weighing, the elutriator filters were shaken in 10 ml of pyrogene free water, which was serially diluted. The amount of airborne endotoxin was determined using the Limulus amoebocyte lysate (LAL) technique.8 Then 0.1 ml of Limulus lysate (Cape Cod Associates) was added to 0 1 ml portions of dilutions of dust filter water extracts. The last dilution giving a stable clot was read as the Escherichia coli endotoxin equivalent concentration. Dilutions were also prepared with commercial E coli endotoxin (E coli 026-B26 Difco) to assess the 340

Exposure of cotton workers in an experimental cardroom with reference to airborne endotoxins.

“…At high dose levels, symptoms can be made to appear also among persons previously without such symptoms and indeed also in subjects previously never exposed to cotton dust (2). The more pronounced decreases in FEV1 among smokers as compared to nonsmokers agrees with earlier studies (8).…”

“…Previously, it has been shown that the number of neutrophils on the nasal respiratory epithelium increases over the shift (2). Neutrophils are activated by endotoxin or gram-negative bacteria on cotton dust and could release mediators for inflammation and bronchoconstriction, such as leukotrienes or platelet activating factor.…”

“…This increase in the peripheral blood reflects the initial migration of neutrophils into the respiratory epithelium (2,8,14), causing a mobilization of neutrophils from the venous marginal pools.…”

<i>Pantoea agglomerans</i>: a marvelous bacterium of evil and good. Part I. Deleterious effects: Dust-borne endotoxins and allergens – focus on cotton dust

“…Haglind and Rylander [95] found in cotton workers and student volunteers exposed to the inhalation of cotton dust in an experimental cardroom, a significant correlation between the concentration of airborne endotoxin and the FEV 1 decrement during the working shift. This relationship was more pronounced in workers who smoked, which suggests that smoking predisposes to enhanced response to inhaled endotoxin.…”

A 20-year follow-up study on chronic respiratory effects of exposure to cotton dust

“…It is generally believed that acute airway obstruction induced by a short-term exposure to cotton dust is reversible [14][15][16]. However, it is not clear whether chronic airway changes associated with long-term exposure are reversible after the exposure ceases.…”