EFFECTS OF SEMICONDUCTOR-LASER IRRADIATION ON THE CELL-CYCLE OF K-562CELLS

The influence of a semiconductor laser on the cell cycle of K-562 cell s was investigated by flow cytometry. After semiconductor laser irradi ation for 15 s at a power of 500 mW, the percentage of cells in the G( 2)/M phase was increased to 31.4+/-1.63 (mean+/-SEM) % as compared wit h 18.5+/-1.26% for the untreated cells (p<0.01). Irradiation for 2 min at 100, 250, or 500 mW, or for 15 s at 100 mW, however, did not signi ficantly affect the cell cycle. The temperature change upon irradiatio n of 100-500 mW, with laser light for 15 s or 2 min was marignal, rang ing from 0.2 to 1.1 degrees C, and no morphological change in the cell s was observed after the irradiation. Based on these results, we assum e that semiconductor laser irradiation under restricted conditions can activate cells in terms of their cell cycle activity by its non-therm al action