Distribution of glass fibers in the peritoneal cavity of the rat following administration by intraperitoneal injection.

The distribution of glass fibers in the peritoneal cavity of the rat was investigated at 2, 24, and 48 h following intraperitoneal injection of 1 mg of material using a radioactive tracer technique. At each time point the peritoneal cavities of the rats killed were lavaged with 20 ml of physiological saline to recover fibers not yet attached to tissue surfaces. At 2 h, 35% of the administered fiber could be recovered by lavage, but at 48 h this was reduced to 2%. At 48 h, the amount of fiber associated with the abdominal organs and the abdominal wall was roughly in proportion to their surface areas. The weight of fiber associated with the various tissues was in the following order: gastrointestinal tract > liver > carcass (abdominal wall) > diaphragm > urogenital tract > spleen > kidneys. Differential counts on cells recovered by lavage were made both on cytocentrifuge slides and by flow cytometry. Compared with controls, the numbers of cells recovered from treated rats at 24 and 48 h were increased by a factor of about 2, due mainly to an influx of neutrophils into the peritoneal cavity. There was a marked reduction in the proportion of mast cells compared to controls.

Alveolar macrophage kinetics after inhalation of 239PuO2 by CBA/Ca mice: changes in synthesis of DNA.

For workers in the nuclear industry, the primary route for the entry of radioactive materials into the body is by inhalation, and the rate of clearance of particles from the pulmonary region of the lung is an important factor in determining radiation dose. It is the function of alveolar macrophages (AM) to maintain the sterility of the lung and to remove insoluble particles from the respiratory surfaces and airways. The AM population is not static, and under normal conditions the loss of macrophages from the alveoli via the conducting airways is balanced by renewal. Studies of the effects of external irradiation on the kinetics of AM are numerous, but to date little is known about the effects of inhaled radioactive particles. In this investigation the effects of inhaled 239PuO2 (plutonium dioxide) particles on the synthesis of DNA by AM were studied at times up to 77 days after exposure. We also measured the number of cells recovered by bronchoalveolar lavage and the incidence of AM with nuclear aberrations. The latter provides a sensitive indicator of the effects of radiation. One of the earliest effects observed after exposure to 239PuO2 is a reduction in the number of AM recovered by lavage. This reduction is associated with a 3-fold reduction in the proportion of AM undergoing DNA synthesis at early times after exposure. The overall mean pulse labeling index of AM recovered from sham-exposed mice is 1.68%, and no trend is observed with time.(ABSTRACT TRUNCATED AT 250 WORDS)

DNA synthesis in alveolar macrophages and other changes in lavaged cells following exposure of CBA/H mice to cigarette smoke.

Traditional methods to determine the proportion of cells in S-phase use radiolabeled precursors of DNA, such as 3H-thymidine, which become incorporated into DNA during its synthesis and are visualized either in tissue sections or in cell preparations by autoradiography. At the Harwell Laboratory the effects of inhaled alpha-emitting actinides on the pulmonary alveolar macrophage population of the rodent lung are being studied. For this research the use of an autoradiographic technique to determine the proportion of cells in S-phase is inappropriate, because of the possible presence of competing sources of radioactivity in the cells under investigation. Consequently, an alternative method has been developed. In this method, 5-bromodeoxyuridine (BrdU), an analogue of thymidine, is incorporated into cells undergoing DNA synthesis. Fluorescein-conjugated monoclonal antibodies, highly specific for BrdU substituted DNA, are available commercially and may be used as a probe for BrdU-labeled cells. This technique for identifying cells in S-phase has been described previously for the flow cytometric analysis of cell suspensions and for cells in tissue sections. An adaptation of this technique for use on cytocentrifuge preparations of cells recovered from mouse lung by bronchoalveolar lavage has been developed and its use is described. Some preliminary results of a short-term experiment with CBA/H mice to determine the effects of exposure to cigarette smoke on the DNA synthesis of alveolar macrophages are also included.