Ultrastructural changes in chondriome of human lymphocytes after irradiation with He-Ne laser: Appearance of giant mitochondria

The structure of mitochondria was studied after the irradiation of human lymphocytes with an He-Ne laser(wavelength, 632.8 nm; dose, 56 J m(-2)). Ultrathin sections of the lymphocytes were studied by electron microscopy 1 h after the irradiation. The irradiation resulted in a 20% increase (p = 0.95) in the number of mitochondrial profiles on the cell section without an increase in their total area. Three-dimensional reconstruction of mitochondria from ultrathin sections through the whole lymphocyte showed that the number of mitochondria was reduced to 9-12 in the irradiated cells compared with 40-45 in the control cells. In the irradiated lymphocytes, 2-4 giant branching mitochondria were also observed among small discrete mitochondria. (C) 1997 Elsevier Science S.A.