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The effects of hyperoxic and hypercarbic gases on tumour blood flow.

Publication ,  Journal Article
Dunn, TJ; Braun, RD; Rhemus, WE; Rosner, GL; Secomb, TW; Tozer, GM; Chaplin, DJ; Dewhirst, MW
Published in: Br J Cancer
April 1999

Carbogen (95% O2 and 5% CO2) has been used in preference to 100% oxygen (O2) as a radiosensitizer, because it is believed that CO2 blocks O2-induced vasoconstriction. However, recent work suggests that both normal and tumour arterioles of dorsal flap window chambers exhibit the opposite: no vasoconstriction vs constriction for O2 vs carbogen breathing respectively. We hypothesized that CO2 content might cause vasoconstriction and investigated the effects of three O2-CO2 breathing mixtures on tumour arteriolar diameter (TAD) and blood flow (TBF). Fischer 344 rats with R3230Ac tumours transplanted into window chambers breathed either 1%, 5%, or 10% CO2 + O2. Intravital microscopy and laser Doppler flowmetry were used to measure TAD and TBF respectively. Animals breathing 1% CO2 had increased mean arterial pressure (MAP), no change in heart rate (HR), transient reduction in TAD and no change in TBF. Rats breathing 5% CO2 (carbogen) had transiently increased MAP, decreased HR, reduced TAD and a sustained 25% TBF decrease. Animals exposed to 10% CO2 experienced a transient decrease in MAP, no HR change, reduced TAD and a 30-40% transient TBF decrease. The effects on MAP, HR, TAD and TBF were not CO2 dose-dependent, suggesting that complex physiologic mechanisms are involved. Nevertheless, when > or = 5% CO2 was breathed, there was clear vasoconstriction and TBF reduction in this model. This suggests that the effects of hypercarbic gases on TBF are site-dependent and that use of carbogen as a radiosensitizer may be counterproductive in certain situations.

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Published In

Br J Cancer

DOI

ISSN

0007-0920

Publication Date

April 1999

Volume

80

Issue

1-2

Start / End Page

117 / 126

Location

England

Related Subject Headings

  • Vasoconstriction
  • Tumor Cells, Cultured
  • Regional Blood Flow
  • Rats, Inbred F344
  • Rats
  • Radiation-Sensitizing Agents
  • Oxygen
  • Oncology & Carcinogenesis
  • Neoplasm Transplantation
  • Models, Theoretical
 

Citation

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MLA
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Dunn, T. J., Braun, R. D., Rhemus, W. E., Rosner, G. L., Secomb, T. W., Tozer, G. M., … Dewhirst, M. W. (1999). The effects of hyperoxic and hypercarbic gases on tumour blood flow. Br J Cancer, 80(1–2), 117–126. https://doi.org/10.1038/sj.bjc.6690330
Dunn, T. J., R. D. Braun, W. E. Rhemus, G. L. Rosner, T. W. Secomb, G. M. Tozer, D. J. Chaplin, and M. W. Dewhirst. “The effects of hyperoxic and hypercarbic gases on tumour blood flow.Br J Cancer 80, no. 1–2 (April 1999): 117–26. https://doi.org/10.1038/sj.bjc.6690330.
Dunn TJ, Braun RD, Rhemus WE, Rosner GL, Secomb TW, Tozer GM, et al. The effects of hyperoxic and hypercarbic gases on tumour blood flow. Br J Cancer. 1999 Apr;80(1–2):117–26.
Dunn, T. J., et al. “The effects of hyperoxic and hypercarbic gases on tumour blood flow.Br J Cancer, vol. 80, no. 1–2, Apr. 1999, pp. 117–26. Pubmed, doi:10.1038/sj.bjc.6690330.
Dunn TJ, Braun RD, Rhemus WE, Rosner GL, Secomb TW, Tozer GM, Chaplin DJ, Dewhirst MW. The effects of hyperoxic and hypercarbic gases on tumour blood flow. Br J Cancer. 1999 Apr;80(1–2):117–126.

Published In

Br J Cancer

DOI

ISSN

0007-0920

Publication Date

April 1999

Volume

80

Issue

1-2

Start / End Page

117 / 126

Location

England

Related Subject Headings

  • Vasoconstriction
  • Tumor Cells, Cultured
  • Regional Blood Flow
  • Rats, Inbred F344
  • Rats
  • Radiation-Sensitizing Agents
  • Oxygen
  • Oncology & Carcinogenesis
  • Neoplasm Transplantation
  • Models, Theoretical