How soon after Hypoxyprobe -1 injection can tissue be harvested for hypoxia analysis?
This question arises because tissues can become anoxic during harvesting. Activation and binding of circulating Hypoxyprobe -1 during this period might, therefore, give false measures of hypoxia. The answer lies in an examination of overall tissue exposure to Hypoxyprobe -1. Overall exposure is defined as marker concentration multiplied by time of exposure at 37oC. Temperature comes into play because the biochemically induced binding is temperature dependent.In principle, a combination of low marker concentration, rapid harvest and immediate fixation in cold medium will eliminate measurable levels of non-specific binding. In the initial human tumor studies, biopsies were taken 16-24 hours after Hypoxprobe -1 infusion (24).The plasma half-life of Hypoxyprobe-1 in humans is ca 5 hours so that 16 to 24 hours represents 3 to 5 half-lives of circulating marker.This means that 1/8 to 1/32 of the initial concentration of marker is present at the time of harvesting. This, combined with rapid t
