The Effects of Inhalation of Grain Dust Extract and Endotoxin on Upper and Lower Airways

The Effects of Inhalation of Grain Dust Extract and Endotoxin on Upper and Lower AirwaysGrain handlers have been shown to have accelerated deterioration of pulmonary function when compared with civic workers. Reductions in airflow have been shown to occur over the course of one workshift and one work week. Both acute deterioration in lung function at work and increased airway reactivity, as assessed by methacholine challenge, appear to correlate with progressive loss of lung function in grain handlers. canadian pharmacy mall

Inhalation of grain dust appears to induce an acute local inflammatory response as well as a systemic response. Increases in peripheral blood granulocyte counts occur between 2 and 24 h after inhalation of grain dust and aqueous grain dust extracts. Bron-choalvolear lavage (BAL) performed on workers exposed to grain dust reveals excess neutrophils in the initial portion of the lavage fluid. Von Essen et al found that neutrophils had infiltrated the mucosa of the lower airways of guinea pigs 24 h after instillation of grain sorghum dust extract. Composite samples from the initial portion of BAL and nasal lavage obtained 24 h after inhalation of nebulized grain dust extract by human volunteers have also demonstrated a predominance of neutrophils.
Recent investigation of the pathogens in grain dust has focused on the hypothesis that endotoxin, which contaminates all organic dusts, may be important in the initial inflammatory response. Dose-response relationships have been shown to exist between levels of respirable dust and symptoms of chest tightness and airflow obstruction in grain, cotton, and swine confinement workers.* Spirometric abnormalities were more strongly associated with airborne endotoxin levels than with inspired dust concentrations in a recent study of animal feed workers. Furthermore, following exposure of healthy adults to Entewbacter agglomerans endotoxin, a dose-response relationship was demonstrated between the quantity of inhaled endotoxin and the severity of airflow obstruction. However, the dose of inhaled endotoxin used (200 fig) to achieve a significant response (FEV! drop of 8.3 percent from baseline) was very high in comparison to most workplace exposures, and resulted in profound adverse systemic symptomatology.
The purpose of this investigation was to compare the effects of inhaled nebulized corn and soybean dust extracts and endotoxin on airway function and inflammation. Our hypothesis was that the physiologic and biologic response to grain dust extracts and endotoxin would be similar as assessed by measures of airflow and mucosal cellularity. Our results indicate that inhalation of grain dust extracts and endotoxin results in airflow obstruction and peripheral blood leukocytosis. Interestingly, only the corn dust extract was associated with a drop in peripheral blood lymphocyte count and an increase in the concentration of nasal lavage lymphocytes.

This entry was posted in Pulmonary Function and tagged airflow obstruction, inhalation, pulmonary function tests, respiratory rates.