Hematoporphyrin derivative photochemotherapy of experimental bladder tumors.
Recent studies have shown that disruption of tumor blood flow is a major consequence of hematoporphyrin derivative photochemotherapy. A series of experiments was undertaken on the transplantable N-(4-(5-nitro-2-furyl)-2-thiazolyl)-formamide induced urothelial tumor in Fischer 344 rats to determine a dose response for both hematoporphyrin derivative and light. Tumor blood flow was used as the biologic criteria of response. Hematoporphyrin derivative doses of 10 micrograms./gm. body weight or above were necessary to cause a significant decrease in tumor blood flow when the tumors were illuminated with 360 joules/cm.2 of noncoherent red light (greater than 590 nm.). With a constant hematoporphyrin derivative dose of 20 micrograms./gm. body weight, significantly lower tumor blood flows were observed with fluences of 240 joules/cm.2 and above. In order to correlate dose response to tumor regression, experiments were done in which tumor dry weights were determined 3 weeks after completion of photochemotherapy (360 joules/cm.2). Hematoporphyrin derivative doses of 10 micrograms./gm. body weight or above were necessary to induce tumor regression. These studies support the hypothesis that disruption of tumor blood flow is a tumoricidal mechanism of hematoporphyrin derivative photochemotherapy.
Selman
S H
SH
Milligan
A J
AJ
Kreimer-Birnbaum
M
M
Keck
R W
RW
Goldblatt
P J
PJ
Britton
S L
SL
D000818:Animals; D004305:Dose-Response Relationship, Drug; D017324:Hematoporphyrin Derivative; D006415:Hematoporphyrins / Q000627:therapeutic use*; D010778:Photochemotherapy; D051381:Rats; D011916:Rats, Inbred F344; D012039:Regional Blood Flow / Q000187:drug effects; D001749:Urinary Bladder Neoplasms / Q000098:blood supply / Q000188:drug therapy*
D006415:Hematoporphyrins; D017324:Hematoporphyrin Derivative