Molecusol as vehicle gave concentrations an order of magnitude higher. Concentrations were comparable to those seen in the mouse, but the metabolite concentrations were lower, and clearance of the drug seemed slow. This could have implications for the use of NITP in man. A method has been developed for the rapid determination of adenine nucleotides to study the energy status of tumours. Rapid decreases in tumour energy charge were observed.
Similar studies involve measurement of lactate in tumour microdialysates.
The aim is to correlate the changes with effects on tumour cell survival and pH. With Dr E Dobrowsky, in vitro studies on energy charge showed this parameter resistant to change, only incubation with succinate causing any significant change in energy status. Time-resolved luminescence techniques are being applied to monitor oxygen tensions in biological systems, involving two different techniques. In the first, a gated image intensifier is switched on a timed intervals after a laser pulse to provide the basis for a digital microscope image of fluorescence in which fluorescence lifetime, rather than intensity, is imaged. Lifetimes of fluorophores may provide information about drug concentration at the microscopic level. In the other project, a ruthenium complex dissolved in silicone rubber at the tip of a fibre optic is excited by a laser pulse or a modulated light-emitting diode.