ABSTRACT
The presence of asbestos bodies in the sputum of individuals with known occupational asbestos exposure has been well documented. However, their prevalence and clinical implications in sputum and bronchial washings from patients not clinically known to have asbestos exposure remains controversial. From 1974 to 1979, 31,353 sputum and bronchial washing specimens were processed in the course of evaluating various pulmonary complaints of approximately 11,000 patients from the outpatient clinics and hospitals of the Harris County Hospital District in Houston, Texas. Asbestos bodies were incidentally found in five patients, and, in retrospect, each of them was discovered to have had significant occupational exposure to asbestos dust. Asbestos lung disease was also subsequently proven in four of the five patients and was felt, retrospectively, to have contributed to their presenting complaints and clinical course. It is concluded that asbestos bodies in sputum and bronchial washing specimens are highly specific markers for past asbestos exposure and reflect the presence of a significant asbestos load within the lungs. Sputum cytology is both painless and inexpensive and is recommended as a supplemental procedure to document clinically significant asbestos exposure.
Subject(s)
Asbestosis/diagnosis , Adolescent , Adult , Asbestosis/epidemiology , Environmental Exposure , Humans , Male , Middle Aged , Sputum/cytologySubject(s)
Asthma/prevention & control , Bronchodilator Agents/therapeutic use , Choline/analogs & derivatives , Theophylline/analogs & derivatives , Adult , Airway Resistance/drug effects , Aminophylline/therapeutic use , Bronchial Provocation Tests , Choline/therapeutic use , Female , Forced Expiratory Volume , Humans , Male , Middle Aged , Theophylline/therapeutic useABSTRACT
It is shown that typical cell elongation curves with time, as reported in the literature, are the consequence of a very simple trend of relative elemental elongation rate with time.
ABSTRACT
Etiolated mung bean hypocotyl segments were incubated in 0.25 m mannitol solutions with indoleacetic acid. They were then deformed mechanically with a longitudinal tensile force at a constant strain rate. The magnitudes of the mechanical forces were comparable to those of the hydrostatic forces existing in normally growing tissues. Each segment was repeatedly deformed and returned to zero force. The total deformation was increased at each cycle.The irreversible and elastic changes in length and diameter were measured for each deformation and the changes in surface area and volume calculated. In addition the applied stress and the work of irreversible and of elastic deformation were determined as functions of deformation.It was found that irreversible elongation, irreversible change in surface area and total change in surface area all were linear functions of total imposed elongation. However, very little change in volume occurred during the deformations.The work of irreversible deformation was found to be independent of temperature between 8 degrees and 25 degrees . It was also virtually independent of rate of deformation measured over a 5-fold range of deformation rates.From these results it is concluded that the irreversible deformation of mung bean hypocotyl tissue occurs by plastic deformation rather than by viscous flow. Thus, the irreversible deformation occurred as a result of breaking cross-links of a cross-linked polymer system.
