Affiliation:
1. Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina 27710
Abstract
Tumor hypoxia is a major barrier to tumor radiation therapy. Typically tumor hypoxia occurs in two forms: chronic and acute. Although the existence of acute hypoxia has long been acknowledged, its temporal characteristics have never been directly measured and documented. In this study tumor[Formula: see text], blood flow (BF), and arterial blood pressure (BP) were measured simultaneously in nine Fischer 344 rats bearing R3230Ac rat mammary adenocarcinomas in the subcutis of the left hindleg. We measured [Formula: see text] at a single location for 36–125 min using recessed-tip oxygen microelectrodes. Simultaneously, we measured tumor BF at two sites within the tumor using laser-Doppler flowmetry (LDF). Similar recordings were made in the quadriceps muscle of seven non-tumor-bearing rats. The [Formula: see text], tumor BF, and BP records were subjected to Fourier analysis.[Formula: see text] and BF showed low-frequency fluctuations (<2 cycles/min) in both tumor and muscle, but the magnitude of the changes in tumor was greater. Tumor BF showed more activity at low frequencies than muscle BF, and the magnitude tended to be greater. No strong correlations were found between[Formula: see text] and BF power spectra for either tumor or muscle or between the frequency patterns of BP and tumor[Formula: see text] spectra. These results quantitatively demonstrate, for the first time, that BF and[Formula: see text] fluctuate at very low frequencies in tumors. In addition to having biological significance for tumor therapy, these fluctuations may have the potential to alter tumor cell behavior via induction of hypoxia reoxygenation injury and/or altered gene expression.
Publisher
American Physiological Society
Subject
Physiology (medical),Cardiology and Cardiovascular Medicine,Physiology
Cited by
103 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献