Selective destabilization of tumor cells with pulsed electric and magnetic sequences: a preliminary report.

BACKGROUND: Various studies in vitro suggest that low electric and magnetic fields may modify cancer cell growth and recent studies in vivo have revealed anti-tumoral effects. After screening different tumor cell lines, we identified specific sequences of localized magnetic and electric fields (MESQ) that reduce cancer cell survival in vitro. This finding led us to design an experiment to determine the actual efficacy of above sequences in selectively destabilizing tumor cells and their effect on healthy cells. MATERIALS AND METHODS: We exposed the MCF7 cancer cell line and normal fibroblasts to MESQ for 1, 2, 3 and 6 hours, evaluating cell survival and induction of apoptosis. RESULTS: Exposure to MESQ reduced MCF7 survival, inducing apoptosis in a timedependent way, whereas fibroblasts were completely unaffected. CONCLUSION: These results have promising implications for the treatment of cancer and warrant further research.

(ECTO) nucleotidase kinetics observed by 31P-NMR spectroscopy: resolution of signals.

We used 31P-NMR to study the action of the drug ouabain, a digitalis glycoside, on the ecto-nucleotidase catalysed reaction pathway: [formula: see text] Even under conditions where it was impossible to resolve all resonances from the individual species, the rate constants for the individual steps may be evaluated by a chi 2 fit of equations describing the global kinetics to the NMR data. The fitted values of the reaction rate constants show no inhibition of any step in the reaction pathway, confirming previous results. This improved kinetic method can be used to evaluate the effect of different substrates, ions and drugs, both in intact or pathologically altered organs and in tissue subcellular fractions.

Some approaches to the pharmacology of multisubstrate enzyme systems.

Analytical and exploratory in vitro, in situ and in vivo, physio-pharmacotoxicology, from enzymology to population epidemiology, now embraces those approaches that correlate complex dynamic multisubstrate kinetics through conventional and more recent non-invasive quantitative methodologies. Basically, substrates may be classed as pertaining to fundamental energy turnovers (first-order cellular metabolic pathways or networks) and to iso- vs allosteric modulator systems (second-order metabolic control network). Pairs of substrates and cofactors set-up the third-order multienzyme-receptor patterns, which in intact, native in vivo structures establish and maintain the compartmentalized, dynamically superimposed overall coordination of local redox and phosphate potentials. Perturbations of the various levels of the metabolic hierarchy induced by drugs, as well their relaxations, can be readily submitted to non-invasive kinetic analysis. Both indirect and direct titrations of substrate levels, their modelling and statistical ad hoc evaluations of their interrelations can lead to the identification of the multiple sites involved in drug effects as structured at the different orders/levels of concomitant functional variations. Fractal geometries contribute towards defining the space- and time-related events.