The antitumor effects of methotrexate with 5-fluorouracil against the Sarcoma 180 mouse tumor model were found to be schedule dependent. Pretreatment of tumor-bearing animals with methotrexate significantly enhanced the antitumor activity of the combination relative to simultaneous treatment or to those with methotrexate following 5-fluorouracil. These studies indirectly support the hypothesis ...

It has been demonstrated that cells killed by heat or irradiation have four times greater affinity for actinomycin D (AMD) than do viable tumor cells. By using a double labeling technique, we were able to show that, with increasing amounts of AMD bound in cells, the incorporation of RNA precursors is proportionally decreased. However, in the presence of nonviable cells or of native DNA, the AMD...

It has previously been reported that the cholecystokinin analog JMV-180 behaves differently on the rat and the mouse cholecystokinin-A receptor (CCK-AR). In mice this analog acts as an agonist on low- and high-affinity sites of the CCK-AR, whereas in rats this compound acts as an agonist on high-affinity sites and as an antagonist on low-affinity sites. In an attempt to understand why the same ...

For nearly 4 years a search has been conducted in our laboratories among materials of natural origin for agents having the ability to retard the growth of tumors. Early in the course of this in vestigation crude culture filtrates of the fungus Aspergillus fumigatus were found to retard the growth of the Crocker mouse sarcoma 180 and of the mammary adenocarcinoma E 0771 in mice (4). Meanwhile, K...

We investigated the enhancing effect of two metal-chelating compounds, 2,3-dimercapto-1-propanesulfonic acid (DMPS) and meso-2,3-dimercaptosuccinic acid (DMSA), on the antitumor activity of cisplatin (CDDP). In the in vivo experiments, DMPS showed a clear synergistic effect and significantly enhanced the antitumor activity of CDDP in terms of survival and life span in mice transplanted with asc...