When 1,3-butadiene is incubated with liver postmitochondrial fractions from mouse, rat, monkey or man and a NADPH-regenerating system, the formation rate of butadiene monoxide is different in the four species. With the exception of the rhesus monkey, the amount of epoxide is proportional to the monooxygenase activity. The sequence of epoxide formation is B6C3F1 mouse, Sprague Dawley rat, man, rhesus monkey. The ratio between mouse and monkey was about 7:1. When 1,3-butadiene is incubated with homogenates from lung tissue, only tissues from mouse and rat produce measurable butadiene monoxide concentrations. The monooxygenase activity in lung tissue of the mouse was only 1/30 that in mouse liver. By contrast, lung tissue formed epoxide concentrations comparable to those formed by liver tissue, whereas monkey and human lung tissue did not produce any measurable levels of butadiene monoxide. The data might suggest that the results of recent rodent inhalation studies with 1,3-butadiene could not automatically be extrapolated to man.
Histologic sections of dog tracheas were taken from 20 dogs anesthetized and intubated for 5 to 7 hours with high-pressure, low-volume Shiley or low-pressure, high-volume Lanz endo-tracheal tubes. Microscopic examination and measurement showed that while the high-pressure, low-volume cuff produced deeper average mucosal erosion, the large-volume, low-pressure cuff resulted in significantly greater lengths of tracheal mucosa-cuff erosion. Maximal depth of penetration throught the basement membrane was similar in both groups. Grooves in the mucosa were seen in 50% of the high-volume-cuff trachea sections but none of the low-volume-cuff tracheal sections. These findings demonstrate that low-pressure, high-volume endotracheal tube cuffs produce different but significant tracheal damage after short-term intubation when compared to high-pressure, low-volume cuffs.
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