Stepdown hyperthermia in human melanoma cells: effects on protracted mild hyperthermia for survival and DNA polymerase inactivation

Melanoma Res. 1995 Aug;5(4):229-34.


Human melanoma cells have been used to evaluate whether stepdown heating (SDH) could increase the effectiveness of long-duration mild hyperthermia (LDMH). The effects of these treatments were also evaluated on cell survival and DNA polymerase inactivation. Short treatments (30 min) at 43 degrees C did not result in much SDH effect for subsequent protracted heating at 40 degrees C. The effect on DNA polymerases was also very small. However, heating at 44 degrees C for 30 min had a large SDH heating effect on subsequent heating at 40 degrees C and 41 degrees C. The SDH effect occurred mainly in the first 5-10 h of subsequent LDMH and, at longer heating times, the rate of cell killing was reduced. The 44 degrees C SDH effect was also observed on DNA polymerase inactivation. Comparing the degree of cell killing and polymerase inactivation showed a good correlation for the various SDH protocols.

Publication types

  • Comparative Study

MeSH terms

  • Cell Death
  • DNA-Directed DNA Polymerase / metabolism*
  • Enzyme Activation
  • Evaluation Studies as Topic
  • Humans
  • Hyperthermia, Induced / methods*
  • Melanoma / enzymology*
  • Melanoma / therapy*
  • Tumor Cells, Cultured


  • DNA-Directed DNA Polymerase