Intrapleurally Injected Colloidal Au 198 and Growth and Implantation of Free Tumor Cells in Pleural Exudate. ∗

Abstract

Summary and Conclusions

(1) Mice inoculated intrapleurally with suspensions of free tumor cells of various strains (S-37, S-180 in CFW mice, carcinoma in C3H mice, Melanoma in dba) were treated 4 or 5 days later, by intrapleural injections of colloidal Au¹⁹⁸ (0.2 mc). After 3 or 4 days, specimens of pleural exudate were withdrawn, stained and compared, as for cellular composition, with those of untreated controls. (2) It was found that in all controls the pleural exudate contained numerous growing (mitoses) tumor cells. Their transfer (intrapleural or intraperitoneal) into normal mice resulted in renewed vigorous growth. However, in treated mice tumor cells were scanty, abnormally shaped, with fewand abnormal mitoses. They were non-viable as demonstrated by their failure to grow after transfer into new mice. Moreover, the exudate of treated mice contained numerous macrophages loaded with clumps of colloidal gold(3). In untreated controls the growth of free tumor cells in the exudate resulted, as a rule, in their implantation into mediastinum and later on in abundant growth of these implants. Only small nodules, often consisting of necrotic tissue, were found in treated animals. (3) Intrapleurally injected colloidal Au¹⁹⁸ was largely stored in the thoracic cavity (in macrophages and in lymphatic tissue), mainly in the mediastinum, but nevertheless it reached the liver and the spleen in considerable amounts. However, it was found that ratio T/A (index of Au¹⁹⁸ distribution between thoracic and abdominal tissues) could be increased by the use of small doses for intrapleural injection of Au¹⁹⁸(5). Infiltration of thoracic tumors with intrapleurally injected Au¹⁹⁸ was noted. (4) It is concluded that irradiation with intrapleurally injected Au¹⁹⁸ induced degeneration and disintegration of free tumor cells in the pleural exudate. It is presumed that inhibition of tumor cell implantation was the result of radiation damage to implanted tumor cells (direct effect) and to the tumor bed (indirect effect on tumor growth).