A method for measuring respiratory deposition of cigarette smoke during smoking.

An understanding of the factors influencing respiratory deposition of cigarette smoke in smokers is needed to accurately control this important source of respiratory exposure in epidemiological studies of workers. Only a few studies have characterized the deposition of cigarette smoke in smokers and these involve methods that interfere with normal smoking. A technique for measuring puff volume, inhaled amount, and respiratory deposition of cigarette smoke particulate phase has been developed. It provides satisfactory accuracy (+/- 10%) and causes minimal disruption of normal smoking pattern. The technique captures exhaled smoke with an exhaust hood and establishes the amount of inhaled smoke by monitoring puff volume, puff duration, and puff timing and replaying the exact smoking sequence with matched cigarettes. Mass of captured cigarette smoke is evaluated by fluorophotometry. Preliminary trials with 11 paid volunteers gave an average puff volume of 53 mL and smoke deposition ranged from 22% to 75% with an average of 47%. Measured depositions are lower than previously published values and higher than would be predicted for submicrometer sized particles during normal breathing.

Marijuana, tetrahydrocannabinol, and pulmonary antibacterial defenses.

Although marijuana is now consumed extensively, little is known of its biologic effects on the lung. To study this problem, the intrapulmonary inactivation of an aerosolized challenge of Staphylococcus aureus was quantified in rats exposed to graded amounts of fresh marijuana smoke. Controls inactivated 85.1 percent +/- 0.3 percent of the bacteria six hours after inoculation. Following an in vivo accumulative exposure to smoke from progressively increasing numbers of marijuana cigarettes for periods of ten minutes each hour for five consecutive hours, intrapulmonary bacterial inactivation was impaired in a dose-dependent manner. Evaluation of the effects of parenterally administered delta-9-tetrahydrocannabinol (THC) or of exposure to fresh smoke from THC-extracted marijuana placebo cigarettes indicated that the cytotoxin in marijuana was not related to the primary psychomimetic component. Thus, marijuana smoke is toxic to the lung and impairs the pulmonary antibacterial defense system in a dose-dependent manner.

The effect of experimental tobacco smoke inhalation on in vitro alveolar macrophage bactericidal function.

The in vitro antibacterial activity of rat alveolar macrophages against a challenge of radiolabeled Staphylococcus epidermidis was studied following 30 and 60 consecutive days of in vivo tobacco smoke inhalation in a dose equivalent to approximately 1 1/2 packs of unfiltered cigarettes per day in man. Macrophages harvested by bronchopulmonary lavage, were cultured, infected, and assayed hourly for 3 hr to determine the relative percentage of surviving radiolabeled intracellular bacteria. Macrophages harvested from smoke-treated rats for 30 days had an impaired capacity to kill bacteria when compared to macrophages from control and sham-smoked animals (63.5% +/- 3.3, 80.8% +/- 3.8, and 86.2% %/- 1.2 killed in 3 hr, respectively). Alveolar macrophages harvested from rats exposed to cigarette smoke for 60 days, however, did not have an impairment in their bactericidal activity relative to matched controls (73.3% +/- 3.9 vs 69.8% +/- 6.9 killed in 3 hr). These data imply that doses of cigarette smoke commonly consumed by man impair the in vitro bactericidal function of the rat alveolar macrophages following 30 consecutive days of experimental smoke treatment. The disappearance of this effect after 60 days of exposure to tobacco smoke suggests that an adaptation to the initial impairment has developed.