No abstract

No abstract

A three-color chromosome in situ suppression technique and classical cytogenetic analysis were compared for the detection of chromosomal aberrations in blood lymphocytes of 27 patients who had undergone radiation therapies from 1 month to 9 years ago. Depending on the respective regimens of therapy, a high variability was found in the aberration data. Aberration rates depended on the interval between exposure and scoring rather than on the locally applied radiation doses, which were rather uniform among most patients. Chromosome in situ suppression was found to be superior to classical cytogenetics with respect not only to the spectrum of detectable aberrations but also to the uncovering of long-term effects of irradiation. Of particular interest were the relative stability of the frequency of radiation-induced reciprocal translocations and the utility of chromosome in situ suppression to uncover complex rearrangements.

2. In a further model, the analysis of hydrogen clearance curves measured in the femoral vein using intravascular needle electrodes in rabbits enabled the distribution of blood flow to be evaluated both under resting conditions and during direct 2 Hz stimulation of the vastus medialis muscle.3. Increased oxygen consumption, induced by stimulation, caused increases in capillary flow which were not necessarily accompanied by augmentation of femoral artery flow.4. Po2 histograms provided no evidence of cellular anoxia even at the maximum level of oxygen consumption.5. A two-compartment distribution of flow was measured under resting conditions, whereas only one compartment could be resolved during 2 Hz stimulation of the vastus medialis muscle in the rabbit experiments. A clear redistribution of flow was observed in the absence of any increase in total flow. 6. A model for oxygen-dependent regulation of capillary blood flow involving high-flow and normal-flow compartments is proposed.

No abstract