Repeated exposure to organic material alters inflammatory and physiological airway responses.

Farmers and smokers are repeatedly exposed to airborne organic material. We hypothesised that farmers and smokers show altered airway responses to inhaled organic, pro-inflammatory agents. A total of 11 farmers, 12 smokers and 12 controls underwent lipopolysaccharide (LPS) bronchial challenge and spent 3 h in a pig barn. Lung function, exhaled nitric oxide and bronchial responsiveness were assessed and nasal lavage fluid and induced sputum were also collected. Symptoms and body temperature were recorded before and after exposures. Following exposure to the pig barn, bronchial responsiveness, exhaled nitric oxide, sputum interleukin (IL)-6, nasal lavage cell count and IL-8 were increased to a greater extent in controls compared to farmers. The sputum IL-6 response was also attenuated in farmers after LPS challenge. The response shown by smokers following exposure to the pig barn was similar to that of controls regarding measurements of exhaled nitric oxide, IL-8 in nasal lavage and IL-6 in sputum, but more similar to farmers concerning bronchial responsiveness and the cell numbers present in nasal lavage. Sputum IL-8 showed a greater increase in smokers than in the other groups following LPS challenge. We conclude that individuals who are repeatedly exposed to organic material develop an adaptation to the effects of acute exposure to inhaled organic material.

The measurement of respiratory and metabolic parameters of patients and controls before and after incremental exercise on bicycle: supporting the effort syndrome hypothesis?

Hyperventilation (HV) occurring out of appropriate context, under some circumstances, can be potentially harmful to health. Nixon (1994) discusses convincingly the negative effects of long-term HV on the alkaloid buffering system and the potential challenge to a person's health status. Using capnography to measure respiration, percent expired CO2, to determine the anaerobic threshold during incremental exercise (the Effort Test), Nixon (1994) documented the onset of metabolic acidosis followed by alkalosis, secondary to the alkaloid buffering system response. Nixon (1994) hypothesized that recurring HV can lead to depletion of the alkaloid buffering system. By combining capnography, during the Effort Test, with analysis of blood gases and specific electrolytes, the effort-syndrome hypothesis was further tested in the present study. Thirteen patients with various kinds of stress-related problems were compared with four control participants. Pretest blood gases, from capillary blood, were collected after 10 minutes rest and 10 minutes of incremental exercise. Exhalation CO2, oxygen saturation, and traditional psychophysiological parameters were measured continuously during the experimental condition. Data from capillary blood and exhalation CO2 are reviewed. Change in patients' alkali buffering system supports the prediction made by Nixon (1994). The complexity of the data as well as methodological procedures of this study warrant a more sophisticated design, with more clearly defined functional analysis.