Polonium-210, which emits alpha particles, is a natural contaminant of tobacco. For an individual smoking two packages of cigarettes a day, the radiation dose to bronchial epithelium from Po(210) inhaled in cigarette smoke probably is at least seven times that from background sources, and in localized areas may be up to 1000 rem or more in 25 years. Radiation from this source may, therefore, be significant in the genesis of bronchial cancer in smokers.
A B S T R A C T We evaluated changes of maximum expiratory flow-volume (MEFV) curves and of partial expiratory flow-volume (PEFV) curves caused by bronchoconstrictor drugs and dust, and compared these to the reverse changes induced by a bronchodilator drug in previously bronchoconstricted subjects. Measurements of maximum flow at constant lung inflation (i.e. liters thoracic gas volume) showed larger changes, both after constriction and after dilation, than measurements of peak expiratory flow rate, 1 sec forced expiratory volume and the slope of the effort-independent portion of MEFV curves. Changes of flow rates on PEFV curves (made after inspiration to mid-vital capacity) were usually larger than those of flow rateson MEFV curves (made after inspiration to total lung capacity). The decreased maximum flow rates after constrictor agents are not caused by changes in lung static recoil force and are attributed to narrowing of small airways, i.e., airways which are uncompressed during forced expirations. Changes of maximum expiratory flow rates at constant lung inflation (e.g. 60% of the control total lung capacity) provide an objective and sensitive measurement of changes in airway caliber which remains valid if total lung capacity is altered during treatment.
We have investigated two patients with multiple myeloma who had a prolonged thrombin clotting time and absent clot retraction but no haemorrhagic diathesis. Coagulation and platelet function studies, as well as electron microscopy of the fibrin clot, indicate abnormal fibrin polymerization; adherence of myeloma protein to very thin fibrin strands results in a rigid translucent clot which fails to retract. This abnormality is not necessarily associated with a haemorrhagic diathesis.
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