The effect of SO2 on the uptake of particles by mouse bronchial epithelium.

In three experiments, we have explored the uptake and transport of colloidal gold (Au) and iron oxide (Fe2O3) by normal and SO2-injured bronchial epithelium. In the first experiment, mice were exposed to a 2-hr aerosol of Au; in the second experiment, mice were exposed to SO2 (250 ppm) for 3 hr, then to Au; and in the third experiment, mice inhaled SO2 and then were exposed to Fe2O3. In each experiment, animals were killed at 0 hr, 1 day, and 4 days postexposure.

Generation and use of three types of iron-oxide aerosol.

Three distinct submicrometric aerosols of iron oxide can be reproducibly generated by combustion of iron pentacarbonyl vapors under varying conditions. Each aerosol was sized with a concentric aerosol spectrometer and was examined with an electron microscope; the specific surface area of each aerosol type was also determined. The "feathers" hematite has a man median aerodynamic diameter (MMAD) of 0.

Lysosomal enzyme activities in pulmonary macrophages from rabbits breathing iron oxide.

The effects of an in vivo exposure to a nontoxic particle, iron oxide, on lysosomal hydrolases in pulmonary macrophages were examined. Rabbits breathed a submicron-sized aerosol of iron oxide for 3 h (mass concentration, 186 to 222 mg/m3). Macrophages were recovered by lung lavage 0, 12, 18, and 24 h later.

Smoking impairs long-term dust clearance from the lung.

The time for the long-term clearance of dust from human lungs was measured. Three heavy cigarette smokers and nine nonsmokers inhaled a harmless trace amount of magnetic dust, Fe3O4. From periodic measurements with a sensitive magnetic detector of the amount of this dust remaining in the lungs, a clearance curve was determined for each subject.

Uptake of iron aerosols by mouse airway epithelium.

Spontaneously breathing mice were exposed to an aerosol of iron oxide for 3 hours. Participation of the tracheal and bronchial epithelium in the uptake of iron oxide was noted immediately following the exposure and at 1 day, 4 days, and 7 days postexposure. Observations with the electron microscope revealed that iron oxide was pinocytosed and converted to ferritin and hemosiderin in all epithelial cell types except mucous cells.

The respiratory tract and the environment.

The primary determinants of pulmonary disease are environmental. The same thinness and delicacy of the air-blood barrier which allows rapid exchange of oxygen and carbon dioxide also reduce its effectiveness as a barrier to inhaled allergens, carcinogens, toxic particles, and noxious gases, and micro-organisms. Adults breath 10,000 to 20,000 liters of air daily.

Lung surface tension and air space dimensions from multiple pressure-volume curves.

Pressure-volume (PV) curves of excised cat, dog, rabbit, and rat lungs were determined in a sequence of three conditions: 1) normal-surface, air-filled; 2) saline-filled; and 3) polyoxyethylene (20) sorbitan monolaurate-(Tween 20) surface, air-filled. Since the surface tension of lung washings containing 2% Tween 20 is constant, the Tween-surface air-filled lungs presumably exhibit the pressure-volume behavior of lungs with constant surface tension. These data along with the assumption of equivalent geometry in the three conditions permit calculation of the variation of surface tension in the normal lung as a function of volume without assuming a specific surface area vs.

Phagocytosis: quantification of rates and intercellular heterogeneity.

We present a method which permits analysis of phagocytic behavior in small samples of macrophages. Both overall phagocytic kinetics and intercellular variability in particle uptake were measured. Macrophages lavaged from Syrian golden hamster lungs were incubated (5 min at 37 degrees C) with 2- to 4-mum plastic particles at 4.

The effect of increased particles on the endocytosis of radiocolloids by pulmonary macrophages in vivo: competitive and toxic effects.

We have developed a technique for measuring the rate of particle ingestion by pulmonary macrophages in vivo. This technique has been used to examine the impact of pre-exposure to ferric oxide, colloidal carbon, and coal dust on the endocytosis of a test particle, colloidal gold. Our technique for estimating endocytosis is as follows: Syrian golden hamsters received intratracheal instillations (0.

Species differences in aerosol deposition.

A theory for scaling the collection efficiency of the lung and respiratory tract is developed by identifying the dimensionless groups of variables controlling the deposition of an inhaled aerosol. The theory predicts that collection efficiency is substantially independent of body size under physiologically equivalent conditions. Thus, total deposition depends primarily on differences in ventilation per gram body weight.

Pathways of clearance in mouse lungs exposed to iron oxide aerosols.

The history of particle clearance was studied in lungs of mice serially sacrificed at intervals up to 14 months following single exposures to an aerosol of submicronic, particulate, iron oxide used as a similitude for atmospheric dust. Clearance was followed by light microscopy in unstained and Prussian blue stained frozen and plastic embedded sections, as well as by electron microscopy, where iron oxide can be recognized by its form. Related problems were investigated through histochemical demonstration of acid phosphatase activity in pulmonary lysosomes and Prussian blue staining of various tissues after administration of iron compounds by gastrointestinal and vascular routes.

The origin of alveolar macrophages in mouse radiation chimeras.

This investigation attempted to determine whether the primary source of alveolar macrophages is pulmonary or hematopoietic. We have utilized an antigenic marker to identify cells of hematopoietic origin. Mouse chimeras were produced by irradiating C57B6/AF(1) mice (900 R) and then injecting them intravenously with B10D2/AF(1) bone marrow.