Combined Effects of X Irradiation and Hyperthermia (42 and 44°C) on Chinese Hamster V-79 Cells in Vitro

Miyakoshi, Junji; Ikebuchi, Motoyoshi; Furukawa, Masayo; Yamagata, Kenzo; Sugahara, Tsutomu; Kano, Eiichi

doi:10.2307/3575023

Cited by 42 publications

(6 citation statements)

References 8 publications

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“…Our data showed a temporal correlation between the onset of thermal tolerance and the decrease in thermal enhancement of radiosensitivity. Likewise, thermotolerance and decreased thermal radiosensitization are also correlated in other studies of (Holahan et al, 1982;Miyakoshi et al, 1979 andHenle et al, 1979). All these results indicate that thermal tolerance in radiosensitization can also occur and these results correlate with the onset of thermotolerance in vitro.…”

Section: Discussionsupporting

confidence: 76%

“…However, their data were complicated by the fact that the conditioning heat treatment 10h before irradiation caused the survival curve Do to increase from 1.17 to 1.42Gy which would result in a larger calculated TER. Further results of Miyakoshi et al (1979) showed that radiosensitization was diminished if low temperature hyperthermia (42.0°C) preceded high temperature hyperthermia at 45.0°C causing thermotolerance. Results from normal tissue studies in vivo also show that a conditioning heat treatment given at various times before subsequent heating and irradiation could result in thermal tolerance and reduced TERs (Henle 1982, Law et al, 1979a,b, Dethlefsen and Dewey 1982.…”

Section: Discussionmentioning

confidence: 97%

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Thermal radiosensitization in Chinese hamster (V79) and mouse C3H 10T 1/2 cells. The thermotolerance effect

Raaphorst¹,

Azzam²

1983

Br J Cancer

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Summary The sensitivity of V79 cells and normal or morphologically transformed C3H-1OT 1/2 cells to Xrays, heat or heat plus X-rays was examined. The normal and transformed C3H-1OT 1/2 cell lines were equally sensitive to heat at 42.0°C and radiation. The V79 cells were more heat sensitive. Thermal radiosensitization occurred for all 3 cell lines for the combined heat and radiation treatments and was greatest for simultaneous treatment. Recovery occurred when the treatments were separated by an incubation interval at 37°C. For the V79 cells, recovery was much greater for X-rays preceding heat compared to X-rays following heat. This difference was not as great in the C3H-1OT 1/2 cell lines. The transformed C3H-1OT 1/2 cells were more sensitive compared to the normal for the simultaneous treatment or for heating followed by irradiation.For prolonged heating at 42.0°C, after which thermotolerance occurred in all 3 cell lines, the radiosensitivity still increased as a function of heating time even though no additional cell killing occurred from the heat treatment alone. For heating V79 cells at 41.0°C no further increase in radiosensitivity occurred, as cells became thermotolerant during prolonged heating. Also for the development of thermotolerance during incubation at 37°C between two heat treatments, thermal radiosensitization decreased demonstrating that thermotolerance can affect radiosensitization by hyperthermia.

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Section: Discussionsupporting

confidence: 76%

Section: Discussionmentioning

confidence: 97%

Thermal radiosensitization in Chinese hamster (V79) and mouse C3H 10T 1/2 cells. The thermotolerance effect

Raaphorst¹,

Azzam²

1983

Br J Cancer

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“…The decay of the SDH effect has been investigated in virro (Miyakoshi et al 1979, Henle 1980, Jung and Kolling 1980, Jung 1982, Rofstad and Brustad 1986, in experimental tumours Kahn 1983, Lindegaard andOvergaard 1987), and in normal tissue in vivo (Miyakoshi et al 1983, Urano and Kahn 1983, Hume and Marigold 1987, Lindegaard and Nielsen 199 1). In these investigations, intervals of different lengths have been introduced between ST and TT.…”

Section: Decay Of the Sdh Effectmentioning

confidence: 99%

“…However, both experiments in virro (Henle and Leeper 1976, 1977, Miyakoshi et al 1979) and in vivo (Hiraoka et al 1987, Lindegaard and Overgaard 1988, Lindegaard er al. However, both experiments in virro (Henle and Leeper 1976, 1977, Miyakoshi et al 1979) and in vivo (Hiraoka et al 1987, Lindegaard and Overgaard 1988, Lindegaard er al.…”

Section: Effect Of Sdh On the Interaction Between Heat And Radiation mentioning

confidence: 99%

Winner of the Lund Science Award 1992 Thermosensitization induced by step-down heating: A review on heat-induced sensitization to hyperthermia alone or hyperthermia combined with radiation

Lindegaard

1992

International Journal of Hyperthermia

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A few minute's exposure to a high temperature (sensitizing treatment, ST) may substantially increase the cytotoxic and the radiosensitizing effect of a subsequent heating at a lower temperature (test treatment, TT). This phenomenon, which is known as step-down heating (SDH) or thermosensitization, has been observed both in cultured cells in vitro and in tumours and normal tissues in vivo. The effect of SDH increases with a lowering of TT temperature, but it is rapidly lost at temperatures very close to 37 degrees C. SDH-induced thermosensitization decays within a few hours, when an interval is inserted between ST and TT. In vitro results suggest an exponential decay of the SDH effect with half times ranging from 1.5- to 3.1 h. The effect of SDH increases with increasing ST time or temperature. For single heating, the Arrhenius plot is biphasic with activation energies of 500-800 and 1200-1700 kJ/mol above and below a break point temperature in the region 42.5-43.0 degrees C, respectively. For SDH, the Arrhenius plot gradually becomes monophasic with increasing severity of ST and it approaches asymptotically to an activation energy of about 400 kJ/mol. The reduction of the activation energy depends on cell survival after the priming ST and not on the specific ST heating time or temperature. SDH strongly enhances hyperthermic radiosensitization with a 5-6-fold reduction of the radiation dose required to achieve tumour control. The thermosensitizing and the radiosensitizing effects of SDH have several features in common. Both effects become more prominent when the TT temperature is decreased and when the ST heating time or temperature increases. In addition, the decay kinetics for both effects are comparable. For heat alone, the effect of SDH in tumour and normal tissue seems to be quantitatively similar. However, the therapeutic ratio may be increased by combining SDH with radiation. Biologically, the critical subcellular targets involved in the SDH effect have not been revealed. However, the ability of SDH to inhibit the clearance of heat-induced aggregation of proteins in the nucleus is interesting. Blockage of the nuclear function by proteins is a central theory in the present molecular biological models for both cell kill by heat and heat radiosensitization. Clinically, SDH may be an advantage since even a short exposure to high temperature increases the effect of an otherwise inadequate heat treatment. The disadvantages are that SDH complicates thermal dose calculations, and may cause unacceptable damage to normal tissue.

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“…In vitro studies suggest that both heatinduced retardation of radiation damage repair and direct heat radiosensitization are enhanced by SDH (Henle and Leeper 1977, Miyakoshi et al . 1979, Warters et al .…”

Section: Introductionmentioning

confidence: 97%

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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Combined Effects of X Irradiation and Hyperthermia (42 and 44°C) on Chinese Hamster V-79 Cells in Vitro

Cited by 42 publications

References 8 publications

Thermal radiosensitization in Chinese hamster (V79) and mouse C3H 10T 1/2 cells. The thermotolerance effect

Thermal radiosensitization in Chinese hamster (V79) and mouse C3H 10T 1/2 cells. The thermotolerance effect

Winner of the Lund Science Award 1992 Thermosensitization induced by step-down heating: A review on heat-induced sensitization to hyperthermia alone or hyperthermia combined with radiation

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

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