Radiofrequency/microwave cell absorption and action spectroscopy. Annual report, 1 September-31 August 1986

Research during the contract year has included the following. An in-vitro tendon-explant model system was used to investigate the effects of weak ELF fields on fibroplasia and collagen synthesis. Maximum (33%) fibroplasia (relative to sham-exposed explants) was induced by 1-Hz square-wave pulsed fields at a time-averaged current density of 7mA/sq.m. Under these conditions, there were no effects on relative collagen synthesis. Lower or higher current densities had relatively less effects on fibroplasia. Maximal response occurred in explants oriented parallel rather than perpendicular to the E-field. At current densities of 14 mA/sq. m, fibroplasia, and collagen synthesis were suppressed but noncollagen protein synthesis was unaffected. A series of duplicate experiments was conducted to determine the effects of pulsed magnetic fields from Helmholtz coils on tendon-explant fibroplasia and collagen synthesis. No effects were detected on either dependent variable. In order to relate pulsed external applied fields to cellular alterations quasi-steady solution of Laplace's equation was obtained and programmed for computation. This solution will be used to calculate induced plasmalemma, nuclear and organelle membrane potentials and karyoplasmic and cytoplasmic potentials in response to pulsed DC electric fields and CW and pulsed RF fields.