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

The Effects of Inhalation of Grain Dust Extract and Endotoxin on Upper and Lower Airways: ResultsPercentage of baseline temperature was elevated significantly 3 and 4 h after inhalation challenge with the endotoxin solution when compared with inhalation challenge with HBSS. While the response after inhalation of the corn dust extract was similar to that of the endotoxin solution, it was not statistically different from HBSS. In contrast, the temperature response after inhalation of soybean dust extract was quite similar to that of HBSS. The heart rate mirrored the temperature responses, with the responses to both corn dust extract and endotoxin being significantly greater than to HBSS. Again, the response to soybean dust extract was most similar to that of HBSS. Respiratory rate was significantly greater 5 and 6 h after challenge with com dust extract than after challenge with HBSS. However, inhalation of both endotoxin and soybean dust extract resulted in changes in the respiratory rate similar to those occurring after inhalation challenge with HBSS (vital signs data not shown). canadian pharmacy

Prechallenge spirometric parameters for individuals did not change significantly between challenges. All subjects developed airflow limitation after challenge with the endotoxin solution, corn, and soybean dust extracts. The baseline FEVi after subjects inhaled the endotoxin solution and solutions prepared from corn and soybean dust extracts were, for most time points, significantly lower between 0.5 and 7 h postexposure than the FEVj after inhalation challenge with HBSS (Fig 1, top). The maximal mean percentage of decrease in FEVi± SD after challenge with HBSS was 0.8±2.1 (range, 0 to 3.6), after the endotoxin solution, 9.9 ±8.5 (range, 1.0 to 22.0), after corn dust extract, 6.9±4.3 (range 1.8 to 13.4), and after soybean dust extract, 5.8 ±3.7 (range 0 to 10.12). For all inhaled substances, the maximal mean percentage of decrease from baseline occurred 30 min after challenge. At 8 and 24 h, these differences were still present; however, they were not statistically significant. The percentage of baseline FVC level was significantly lower after inhalation of com dust extract than after HBSS 2 h postchallenge and at all subsequent time points, including 24 h postchallenge (Fig 1, center). This significantly lower baseline FVC was also seen between 1 and 5 h after challenge with endotoxin. After challenge with soybean dust extract, the percentage of baseline FVC was very similar to HBSS, but then gradually decreased, and became significantly different from HBSS 24 h postinhalation challenge. Thirty minutes after inhalation challenge, the percentage of baseline FEVi/FVC level measured for endotoxin, corn, and soybean dust extracts decreased significantly compared with HBSS (Fig 1, bottom). Thereafter, with the exception of several isolated time points, these ratios, though consistently lower, were not significantly different from those after challenge with HBSS.
Baseline peripheral blood leukocyte counts were not significantly different between subjects prior to the inhalation challenges. Total peripheral blood leukocyte counts 6 h after inhalation of endotoxin and extracts prepared from com and soybean dusts were significantly higher than their respective baseline values (data not shown), and in comparison to the response following inhalation of HBSS (Fig 2).

Figure-1

Figure 1. Change in FEV, (top), FVC (center), and FEV,/FVC (bottom), after inhalation challenge. HBSS = Hanks’ balanced salt solution; endotoxin = E coli (serotype 0111:B4) endotoxin diluted in HBSS; corn = aqueous extract of settled corn dust; soy = aqueous extract of soybean dust. Asterisk *p<0.05 compared with HBSS (Wilcoxon).

Figure-2

Figure 2. Percent baseline peripheral blood WBC count 6 h after inhalation challenge. HBSS = Hanks’ balanced salt solution; endotoxin = E coli (serotype 0111:B4) endotoxin diluted in HBSS; corn = aqueous extract of settled corn dust; soy = aqueous extract of soybean dust. Asterisk = p<0.05 compared with HBSS (Wilcoxon).

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