Radioresistance of anoxic cells and the effects of PNAP on the radiation response of an in vitro tumor model.
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Biomedical subjects
F W Hetzel
Publications and source records attributed to F W Hetzel.
Development of lymph node and pulmonary metastases after local irradiation and hyperthermia of footpad melanomas.
C57BL/6 mice with syngeneic B16-F10 melanomas were treated 7 days after tumor inoculation into the footpad with local hyperthermia (HT) of 43.5 degrees C for 90 min. A combination of local 30 Gy X-irradiation (XRT) given 2, 4 or 12 h after HT cured the primary tumor in 34/35 mice, with irreversible damage to normal foot tissues in most of the animals. When 7.5, 10 or 15 Gy XRT were delivered 4, 18 or 24 h after HT, there were only a small number of cures and also a much smaller incidence of irreversible normal tissue damage. HT alone resulted in a significant (P less than 0.001) increase in metastases to regional lymph nodes (RLN) and the lungs. The 'curative' doses of combined XRT and HT resulted in a significant (P less than 0.001) decrease in metastasis to RLN and to the lungs. Conversely, subcurative doses of combined therapy resulted in an increase in RLN and lung metastasis (P less than 0.001). Abdominal lymph node metastasis, not usually seen in control mice, is markedly increased after HT alone or in combination with subcurative XRT (P less than 0.001). The overall survival of mice treated with HT alone is decreased (P less than 0.0028). The survival of mice treated with HT followed 4, 18 or 24 h later with 10 Gy XRT is further decreased (P less than 0.0025). These data show that subcurative HT, or XRT plus HT, increases the incidence of spontaneous metastasis in this syngeneic mouse melanoma model. Curative doses prevent this effect on metastasis, but there is an unacceptable incidence of irreversible damage to the tumor-bearing foot. The cause(s) of this phenomenon are not known.
Animals↗
In vivo 31-P NMR of photoactivated hematoporphyrin derivative in cat brain.
In vivo 31-P nuclear magnetic resonance (NMR) spectroscopy was performed on cat brains injected with hematoporphyrin derivative (HpD). A 2-cm-diam region of the right parietal lobe was photoactivated with red light. The 31-P NMR spectra of the photoactivated hemisphere revealed increased inorganic phosphate and decreased phosphocreatine and adenosine triphosphate (ATP) levels, compared to spectra obtained from the control hemisphere. In the absence of drug, no difference in spectra was observed between the photoradiated and control lobes. Our studies suggest that in vivo 31-P NMR spectroscopy may be used to monitor the effects of phototherapy on tissue high-energy phosphate metabolism.
Animals↗