No evidence of cellular alterations by MilliTesla-level static and 50 Hz magnetic fields on S. cerevisiae.

In an attempt to determine whether magnetic field (MF) exposures might induce cellular alterations, S. cerevisiae yeast cells were exposed to static or sinusoidal 50 Hz homogeneous MF (0.35 mT, 1.4 mT, and 2.45 mT) for 1 h and 72 h. Unsynchronized cells grown exponentially while exposed to MF, containing cells in all stages of the mitotic cell cycle. MF was generated by a pair of Helmholtz coils (40 cm in diameter, coaxial, separated by 20 cm). Survival, cell cycle distribution, colony forming ability, and mutation frequency were assayed. No differences in the above-mentioned parameters were observed in MF exposed samples in relation to unexposed controls, suggesting that homogeneous MF at these intensities do not produce appreciable cellular alterations in this organism under typical in vitro growth conditions.

No effect of 50 Hz 2.45 mT magnetic field on the potency of cisplatin, mitomycin C, and methotrexate in S. cerevisiae.

Drug resistance is an obstacle for chemotherapy success. Because of this, this work aims to improve the cell killing effect of antineoplastic drugs by magnetic field (MF) co-exposure. S. cerevisiae cells were exposed to 2.45 mT, sinusoidal 50 Hz MF, during 48 h, and the drugs cisplatin (cisPt), mitomycin C (MMC), or methotrexate (MTX); 100 and 1,000 microg/ml. Survival was assayed by the drop test. The results showed that MF exposures do not induce alterations in the potency of cisPt, MMC, and MTX on these cells in relation to untreated controls. In addition, a strong correlation between temperature and potency of cisPt was found, which contribute to the establishment of the importance of an exhaustive control of temperature in experiments carried out with temperature sensitive antineoplastic agents in co-exposure with MF; avoiding differences between MF-exposed samples and unexposed controls and contributing to the performance of experiments under well-defined and controlled conditions.

Static and 50 Hz magnetic fields of 0.35 and 2.45 mT have no effect on the growth of Saccharomyces cerevisiae.

The present work reports the growth effects induced by static and sinusoidal 50 Hz magnetic fields (MF) on the haploid yeast strain Saccharomyces cerevisiae WS8105-1C. Magnetic fields were generated by a pair of Helmholtz coils (40 cm in diameter) with 154 turns of copper wire in each and separated 20 cm. The experiments were performed at 0.35 and 2.45 mT, and yeasts were exposed to MF during 24 and 72 h in the homogeneous field area. Growth was monitored by measuring the optical density at 600 nm. The data presented in the current report indicate that static and sinusoidal 50 Hz MF (0.35 and 2.45 mT) do not induce alterations in the growth of S. cerevisiae.

Influence of 1 and 25 Hz, 1.5 mT magnetic fields on antitumor drug potency in a human adenocarcinoma cell line.

The resistance of tumor cells to antineoplastic agents is a major obstacle during cancer chemotherapy. Many authors have observed that some exposure protocols to pulsed electromagnetic fields (PEMF) can alter the efficacy of anticancer drugs; nevertheless, the observations are not clear. We have evaluated whether a group of PEMF pulses (1.5 mT peak, repeated at 1 and 25 Hz) produces alterations of drug potency on a multidrug resistant human colon adenocarcinoma (HCA) cell line, HCA-2/1(cch). The experiments were performed including (a) exposures to drug and PEMF exposure for 1 h at the same time, (b) drug exposure for 1 h, and then exposure to PEMF for the next 2 days (2 h/day). Drugs used were vincristine (VCR), mitomycin C (MMC), and cisplatin. Cell viability was measured by the neutral red stain cytotoxicity test. The results obtained were: (a) The 1 Hz PEMF increased VCR cytotoxicity (P < 0.01), exhibiting 6.1% of survival at 47.5 microg/ml, the highest dose for which sham exposed groups showed a 19.8% of survival. For MMC at 47.5 microg/ml, the % of survival changed significantly from 19.2% in sham exposed groups to 5.3% using 25 Hz (P < 0.001). Cisplatin showed a significant reduction in the % of survival (44.2-39.1%, P < 0.05) at 25 Hz and 47.5 microg/ml, and (b) Minor significant alterations were observed after nonsimultaneous exposure of cells to PEMF and drug. The data indicate that PEMF can induce modulation of cytostatic agents in HCA-2/1(cch), with an increased effect when PEMF was applied at the same time as the drug. The type of drug, dose, frequency, and duration of PEMF exposure could influence this modulation.