Integrated optical density and entropiefluss (current of entropy) in bronchial carcinoma.

Histological sections of formalin-fixed, paraffin-embedded bronchial carcinomas comprising 241 surgical specimens (lobes and lungs) were Feulgen stained. The integrated optical density of the nuclei (IOD) and the minimum distance between their centers of gravity (DG) was measured with an automated image analyzing system consisting of a TV camera connected to a personal computer via a frame grapper. Intratumorous lymphocytes served as DNA standard (2C peak), and 300 nuclei were measured at minimum. The entropy of the IOD, the percentage of S-phases (PS) of tumor cells with an IOD > 3C and > 5C, and the 2CV mean standard deviation were measured. According the theory of thermodynamically open systems, the entropiefluss (current of entropy) was defined by the gradient IOD/time through the surface of the tumors which can be approximated by the formula IODPSDG/tumor volume. The following results were obtained: a) IOD of bronchial carcinoma is not associated with tumor size or lymph node infiltration (pT and pN stage). b) The minimum distance between tumor cells decreases with increasing tumor stage and increasing lymph node stage (pT, pN stage). c) The entropiefluss is low in limited and advanced tumor stages, and highest in tumors at moderately progressive tumor stages (pT2, pT3, pN1, pN2). Thus, in accordance with the theory of thermodynamically open systems, the entropiefluss reflects the "biological activity" of bronchial carcinoma.