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Biomedical subjects

M Dittrick

Publications and source records attributed to M Dittrick.

6 recordsLinked to original sources

Occupational asthma due to exposure to African cherry (Makore) wood dust.

A 35-year-old man who had been a carpenter and a cabinet worker for over 15 years, was referred to our clinic with a 4-month history of cough, chest tightness and difficulty in breathing which occurred within minutes of exposure to African cherry wood (Makore). He developed a dual asthmatic reaction on specific challenge test with an extract of African cherry wood dust. Thus, the diagnosis of occupational asthma due to exposure to African cherry wood dust was confirmed by the specific challenge test. The mechanism of asthma due to African cherry wood dust exposure is not clear.

Adult↗

Airway inflammation, exhaled nitric oxide, and severity of asthma in patients with western red cedar asthma.

Examination of induced sputum and measurement of exhaled NO have been advocated as noninvasive methods of assessing the degree of airway inflammation. In this study, we performed follow-up evaluation on 71 subjects with asthma caused by exposure to Western red cedar; 50 subjects had left exposure, whereas the rest continued to work in the same job. Spirometry, methacholine challenge tests, exhaled nitric oxide, and sputum induction were carried out. Of the 50 subjects who left exposure, 12 had no respiratory impairment according to the American Throacic Society guidelines for assessing respiratory impairment in patients with asthma, 17 belonged to Class 1, 12 to Class 2, five to Class 3, and four to Class 4. The percentage of eosinophils in induced sputum showed a significant inverse relationship with FEV1 (r = -0.46, p < 0.001), and a significant positive correlation with levels of exhaled NO (r = 0.42, p < 0.001) and with the class of respiratory impairment (r = 0.52, p < 0.001). Mean percent eosinophils were 1.5 for impairment Class 0, 2.2 for Class 1, 1.7 for Class 2, 6.8 for Class 3, and 16.3 for Class 4. No relationship was found between the levels of exhaled NO and the functional parameters as well as the impairment class. NO levels in ppb were 21 for impairment Class 0, 30 for Class 1, 22 for Class 2, 26 for Class 3, and 49 for Class 4. This study also provides objective evidence that airway inflammation, as indicated by induced sputum, corroborates the rating of respiratory impairment in patients with asthma.

Adult↗

Sputum eosinophils and exhaled nitric oxide during late asthmatic reaction in patients with western red cedar asthma.

Examination of sputum for eosinophils and measurement of exhaled nitric oxide have been proposed as noninvasive methods of assessing airway inflammation in asthma. The use of these tests in the evaluation of patients with occupational asthma has not been reported. This study investigated the changes in sputum eosinophils and exhaled NO before and at intervals after inhalation challenge with plicatic acid in patients with suspected western red cedar asthma. Of 17 subjects who underwent challenge, nine had a positive bronchoconstrictor reaction (responders) and eight had a negative reaction (nonresponders). At 6 and 24 h after plicatic acid challenge, there was a significant increase in sputum eosinophils among responders, which was inversely related to the fall in forced expiratory volume in one second (FEV1) at 6 h. An increase in sputum eosinophils was also found in three nonresponders. Levels of exhaled NO increased at 24 h after challenge with plicatic acid in both responders and nonresponders, being significant only in nonresponders. No correlation was found between the increase in nitric oxide and the magnitude of the functional changes in the airways. There were significant correlations between the degree of sputum eosinophilia and the level of exhaled NO before and after methacholine and plicatic acid challenge. In conclusion, the late asthmatic reaction induced by plicatic acid in patients with western red cedar asthma is associated with an increase in sputum eosinophils. The usefulness of measuring sputum eosinophils and exhaled nitric oxide in the clinical evaluation of patients with suspected occupational asthma caused by low molecular weight compounds has yet to be determined.

Adult↗

Western red cedar dust exposure and lung function: a dose-response relationship.

The relationship between levels of cumulative red cedar dust exposure and decline in lung function was explored in an 11-yr follow-up study of 243 sawmill workers who participated in at least two occasions. We also studied 140 office workers in a similar manner as control subjects. Workers with asthma were excluded from the analysis. During the period of the study, 916 personal and 216 area samples of dust were collected from the sawmill. Cumulative wood dust exposure was calculated for each sawmill worker according to the duration and exposure in each job, based on the geometric mean of all dust measurements for that job. Average daily dust exposure was calculated by dividing the total cumulative exposure by the number of days of work. Workers were divided into low-, medium-, and high-exposure groups with mean daily level of exposure of < 0.2, 0.2 to 0.4, and > 0.4 mg/m3, respectively. Sawmill workers had significantly greater declines in FEV1 and FVC compared with office workers adjusted for age, smoking, and initial lung function. A dose-response relationship was observed between the level of exposure and the annual decline in FVC. We conclude that exposure to Western red cedar dust is associated with a greater decline in lung function which may lead to development of chronic airflow limitation.

Adult↗