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Grading based on histopathologic features is used to predict survival in soft-tissue sarcoma. However, variations in clinical behavior between tumors of the same grade motivate a search for additional factors that correlate with prognosis. Proliferating cell nuclear antigen (PCNA) is expressed in proliferating cells during the G1, S and G2-phases. To evaluate a prognostic implication of PCNA, the tumors of 48 patients with malignant fibrous histiocytomas (13 grade III, 35 grade IV) with a minimum follow-up of 2 years were immunohistochemically studied. We used PC10, a monoclonal antibody (MAb) directed against PCNA, which allows cell proliferation in formalin-fixed, paraffin-embedded tumor tissue to be evaluated. We applied a semiquantitative PCNA grading scheme to all stained nuclei of an entire slide. The 3-year metastasis-free survival rate was 0.87 for patients in grade A (low PLNA rate), and 0.14 for patients in grade C (high PLNA). Our findings show that immunohistochemical evaluation of cell kinetics in soft-tissue sarcomas by PCNA might be a useful adjunct to conventional tumor grading.

There is evidence that the administration of pyridoxine hydrochloride successfully prevents the "radiation sickness" which may appear a few hours after a therapeutic dose of irradiation (Manfield, McIlwain, and Robertson, 1943 : Shorvon, 1949). Pyridoxine has also been reported to reduce the mortality of mice given whole body x-irradiation (Goldfeder, Cohen, Miller, and Singer, 1948). In seeking for an explanation of this action we considered the relation of pyridoxine to the formation of the pressor amines, noradrenaline and adrenaline, which occur in the adrenal medulla. One of us (Blaschko, 1939) has put forward the view that the enzyme dopa-decarboxylase (dopa is dihydroxy-phenylalanine) discovered by Holtz, Heise, and Ludtke (1938) If it is true that dopa-decarboxylase is an important enzyme in the process of noradrenaline formation, then rats fed on a pyridoxine-deficient diet should have difficulty in maintaining a normal content of pressor amines in the adrenal medulla. Blaschko, Burn, and Carter (unpublished) have found that, when the adrenal medulla is depleted as a result of the injection of insulin, rats fed on a pyridoxine-deficient diet cannot replenish the store of pressor amines so effectively as controls given a supplement of pyridoxine. The inability to replenish the store is, however, only evident in those rats in which the amount of dopa-decarboxylase in the liver is too small to be detected by manometric observations. The experiments to be described have therefore been directed to examining changes in the amount of dopa-decarboxylase in the livers of irradiated rats, and also changes in the amount of pressor amines in the adrenal medulla both before and after the injection of insulin. Estimation of dopa-decarboxylase.-The livers were at once frozen in an ice-cooled mortar at almost -10' C. and ground up with a little sand; 0.067 M-sodium phosphate

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