Peripheral blood lymphocyte nucleoli of rats with Yoshida ascitic sarcoma and the effect of cyclophosphamide.

Changes in the leucocytes, lymphocytes and peripheral blood lymphocyte nucleoli of Yoshida ascitic sarcoma bearing rats untreated and treated with cyclophosphamide were studied. In the course of the growth of Yoshida ascitic sarcoma lymphocytes with "active" nucleoli (compact nucleoli and nucleoli with nucleolonemas) first increased and then, in the terminal stage of the disease, decreased in number. The number of lymphocytes with ring-shaped nucleoli ("reversibly inactive") and micronucleoli was rising throughout the disease. The increase in numbers of micronucleoli in the lymphocytes produced increased values of nucleolar coefficient. After administration of cyclophosphamide to rats with transplanted tumour the number of lymphocytes with both "active" and "reversibly inactive" nucleoli decreased and the number of lymphocytes with micronucleoli increased. The increase in the proportion of micronucleoli also led to increased values of nucleolar coefficient. After cessation of cyclophosphamide treatment and when the signs of the neoplastic disease had disappeared, the changes observed in the white blood cell picture returned to the values before sarcoma transplantation.