[Magnetic susceptibility of rhodopsin molecules]

It has been calculated that if rhodopsin molecules are associated in photoreceptor membranes they have such a high diamagnetic susceptibility anisotropy that it manifests itself macroscopically in the magnetic field in the order of magnitude of 0.1 kG (8 . 10(3) A/m), but the velocity of this orientation is very low. Thus the interaction with the magnetic field might be limited by kinetics. Malignant transformation is as a rule accompanied by changes in 1) the properties of membrane proteins, 2) their orientation in the membrane, 3) the physical state of lipids in which the membrane proteins are located. Under definite conditions these changes can lead to selective effects of the magnetic fields on the growth of cancer cells in vitro and in vivo (see ref. 2). It is also suggested from thermodynamic considerations that the magnetic anisotropy of biological material (membrane proteins, collagenous structures, muscle and chromatin fibres) might be one of the bases of other biological effects of magnetic fields.