Effect of step-down heating on hyperthermic radiosensitization in an experimental tumor and a normal tissue in vivo

Lindegaard, J.C.; Overgaard, Jens

doi:10.1016/0167-8140(88)90250-2

Cited by 21 publications

(8 citation statements)

References 24 publications

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“…TCD 50 was calculated by logit analysis (Lindegaard and Overgaard 1988) . The effect of combining heat and radiation was quantitated as the thermal enhancement ratio (TER)=TCD 50 (radiation alone)/TCD SO (heat and Int J Radiat Biol Downloaded from informahealthcare.com by University of Melbourne on 11/05/14…”

Section: Evaluation Of Resultsmentioning

confidence: 99%

“…5°C showed that the radiosensitizing effect of SDH increased with increasing TT time (Lindegaard and Overgaard 1988) . To investigate the importance of both time and temperature, TT temperatures in the range 41 .0-43 .…”

Section: 2 Radiosensitizing Effect Of Single Step-up and Step-downmentioning

confidence: 98%

“…1987 . In vivo, a prominent enhancement of hyperthermic radiosensitization was found for a simultaneous application of SDH and radiation in a C3H mammary carcinoma (Lindegaard and Overgaard 1988) .…”

Section: Introductionmentioning

confidence: 99%

“…Apart from the TT heating time, these parameters were all fixed in the previous in vivo study of SDH and radiation, and only a simultaneous application of SDH and radiation was investigated (Lindegaard and Overgaard 1988) .…”

Section: Introductionmentioning

confidence: 99%

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Effect of Step-down Heating on the Interaction between Heat and Radiation in a C3H Mammary Carcinomain Vivo

Lindegaard

Grau

Overgaard

1991

International Journal of Radiation Biology

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The effect of step-down heating (SDH) on the interaction between heat and radiation was investigated in a C3H mammary carcinoma in vivo. SDH consisted of an initial sensitizing treatment (ST) performed at 44.5 degrees C or 43.5 degrees C followed by a lower temperature test treatment (TT) in the range 41.0-43.0 degrees C. Step-up heating (SUH), i.e. TT followed by ST, and single heating were used as controls. The end-point was the radiation dose needed to control 50% of the tumours (TCD50). The results were evaluated by calculating the thermal enhancement ratio (TER) defined as TER = TCD50 (radiation alone)/TCD50 (radiation and heat). For a simultaneous application of TT and radiation a significant enhancement of direct heat radiosensitization was observed with increasing ST time or ST temperature using SDH. In contrast, only a minor increase was seen with SUH. A comparison between TCD50 values for the corresponding SUH and SDH schedules revealed that the SDH effect was largest at 41.0-42.0 degrees C and decreased with increasing TT temperature. The radiosensitizing effect of SDH also decreased if an interval was allowed between ST and TT or between TT and radiation. However, as a result of an increased cytotoxicity towards hypoxic tumour cells, the TCD50 value for SDH remained significantly smaller than for SUH, even with a sequential combination of radiation and heat.

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Section: Evaluation Of Resultsmentioning

confidence: 99%

Section: 2 Radiosensitizing Effect Of Single Step-up and Step-downmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Effect of Step-down Heating on the Interaction between Heat and Radiation in a C3H Mammary Carcinomain Vivo

Lindegaard

Grau

Overgaard

1991

International Journal of Radiation Biology

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“…Since S D H will also enhance the toxicity to normal tissue, the therapeutic value of such a scheme (in combination with cDDP) must be carefully evaluated. Although for hyperthermia alone SDH data from animal studies are inconclusive regarding possible therapeutic gain (reviewed by Lindegaard, 1992), the results from studies on the combination of SDH and radiation appear promising (Lindegaard and Overgaard, 1988).…”

Section: Discussionmentioning

confidence: 99%

Sensitization to cisplatin action by step‐down heating in cddp‐sensitive and ‐resistant cells

Hettinga

Lemstra

Devries

et al. 1995

Intl Journal of Cancer

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Hyperthermia treatment (> or = 43 degrees C) has been shown to be able to (partially) reverse acquired cDDP resistance. However, such heat treatment is difficult to achieve in the clinic. Short pre-treatment at a high temperature (> 42 degrees C), immediately before a treatment at a lower temperature (< 42 degrees C) can enhance the heat toxicity of the lower temperatures. This "step-down heating schedule" was explored for its possible drug-sensitizing potential in in vitro-cultured cDDP-sensitive and -resistant murine and human tumour cells. A 10-min pre-treatment at 44 degrees C enhanced the cytotoxicity of 41 degrees C hyperthermia alone. It also enhanced sensitivity to cDDP when given at 37 degrees C. However, it did not increase the 41 degrees C-induced cDDP sensitization. Thus, no correlation was found between heat kill and cDDP sensitization for step-down heating schedules. The observed effects of step-down heating were comparable in sensitive and in resistant cells, so the step-down heating schedule, unlike the 43 degrees C treatment, did not lead to a decrease of the cDDP-resistance factor. Yet the total cytotoxicity caused by this treatment protocol was 10-fold more than for cDDP with 41 degrees C alone, due to the extra hyperthermic cell killing and the cDDP-sensitizing effect of the pre-treatment. This treatment could have a substantial impact on cDDP efficacy in the clinic even when cDDP resistance has developed.

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Interaction of Heat and Radiation In Vitro and In Vivo

Konings

1995

Thermoradiotherapy and Thermochemotherapy

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Effect of step-down heating on hyperthermic radiosensitization in an experimental tumor and a normal tissue in vivo

Cited by 21 publications

References 24 publications

Effect of Step-down Heating on the Interaction between Heat and Radiation in a C3H Mammary Carcinomain Vivo

Effect of Step-down Heating on the Interaction between Heat and Radiation in a C3H Mammary Carcinomain Vivo

Sensitization to cisplatin action by step‐down heating in cddp‐sensitive and ‐resistant cells

Interaction of Heat and Radiation In Vitro and In Vivo

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