The effects of melphalan and misonidazole on the vasculature of a murine sarcoma.

A method for estimating both structural and functional vascular volumes in murine sarcomas is described. Intact vessels were demonstrated by the presence of laminin, a basement membrane-associated antigen, using an immunofluorescent technique, and functional vessels in the same sample by prior injection with the DNA binding dye Hoechst 33342. No significant vascular effects were seen after melphalan but a very pronounced decrease in both functional and structural vascular volume was seen after MISO. Combined chemotherapy of a murine sarcoma with melphalan and MISO induced a rapid decrease in the functional vascular volume, and there was a resumption of blood flow prior to measurable regrowth. The fully regrown tumour retained the vascular characteristics of untreated tumours of similar size.