Abstract— The biological effects of single and 4‐time irradiation of primary human embryo fibroblasts with 4 J/cm2 polarized light emitted by a halogen light source were investigated. The functional state of the plasma membrane was examined by means of lectin‐binding and polycationized ferritin‐binding techniques. It was established that the Con A binding of the cells did not change, whereas the number of negatively charged binding sites increased to a significant degree in relation to the untreated (control) samples and cell cultures exposed to diffuse (non‐polarized) light. The micromorphological examinations showed no ultrastructural deviations. The quantitative increase of negative surface charges may be regarded as an indication of the biological effect of polarized light exerted on the cell membrane. The modifying effect of polarized light on the survival of E. coli exposed to the ionizing radiation was manifested in decreased anoxic radiation response.

SummaryThe biological effect of visible light of low energy density was investigated in this study. The effects of diffuse (DL) and linearly polarized (LPL) light were compared on models in vitro and in vivo.Experiments in vitro were performed on human lymphocytes to study their blast-transformation and rosette-formation abilities. Both DL and LPL increased the number of blast-transformed cells even in a lymphocyte culture without PHA, and reduced rosette-formation of T lymphocytes. LPL had a more pronounced effect.In vivo exposure to DL and LPL of the spleens of tumour-bearing mice caused the appearance of factor(s) in their serum, inhibiting the incorporation in vitro of [^H]-thymidine into the tumour cells obtained from non-exposed animals. In the other series of experiments serum samples were taken from tumorous animals after the exposure of their spleens to LPL. Following the daily administration of these sera to another group of non-exposed tumorous mice a decreasing tendency of the mitotic kinetics of ascites tumour was observed.The application of visible (preferably linearly polarized) light for the stimulation of human immune competent cells, and clinical trials with extracorporeal irradiation of blood for the promotion of natural defences of an immune-repressed organism are suggested.

A 1-J/cm2 dose of single laser-irradiation applied on primary human embryo fibroblast culture was not followed either by functional or micromorphological alterations of cell surfaces. This dose, however, applied four times with 24-hour intervals changed the functional conditions as well as surface charges of cell membranes. As detection methods, radioactive glucosamine uptake, lectin, and cationized ferritin-binding techniques were applied. At the same time, the scanning and transmission electron microscopy of laser-irradiated cells did not reveal any micromorphological or ultrastructural alterations. The effect of a 5-J/cm2 dose did not differ from that of 1 J/cm2. It is suggested that laser radiation-induced circumstances on cell surfaces can contribute to the strength of cell-to-cell contacts, i.e., to the stimulation of epithelization experienced in the clinical gynecologic practice.

Early, dose-dependent and transient alterations were observed in the plasma membranes of human blood cells after X-irradiation in vitro as detected by a concanavalin A-binding technique. Platelets, lymphocytes and erythrocytes, separated in a one-step procedure from a single blood sample, showed different radiosensitivities within the dose range of 0.1--5 Gy. The complex evaluation of the surface alterations of blood cells might indicate the range of the absorbed dose.

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By binding cationized ferritin (CF) to the plasma membrane of primary human fibroblasts, the amount and topology of negatively charged sites on cell surfaces were studied after X-irradiation. The CF binding was tested both on fixed and unfixed cells. Using various enzymes, the chemical nature of sites carrying the negative charges on cell surfaces was investigated. The results suggest that in unirradiated fibroblasts the CF binding occurred in a polarized manner, i.e. the particles were localized mainly on the apical surface of cells and formed clusters. The thin cytoplasmic protrusions and cell-to-cell contact sites bound CF to a greater extent than the bleb-like formations. Enzymatic digestion of surface polysaccharides showed that the main carriers of negatively charged sites are the glycosaminoglycans associated with the cell surface. The fixation of cells with glutaraldehyde did not influence the topology of CF binding either before or after the enzymatic treatment. After X-irradiation with 2.5 Gy the topology of CF binding did not change but the CF coverage of cells as well as the amount of ferritin particles per unit of surface area decreased within 10 min. The changes proved to be reversible as the values reached the pre-irradiation level by 1 h after irradiation.

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The topologies of bindings of cationized CF and native ferritin (NF) on plasma membranes of primary human fibroblasts were examined by transmission electronmicroscopy. Both ligands bound mainly to apical surfaces and less abundantly to lateral regions. At basal localization they were observed only at cell-to-cell connections. The polarity of negatively charged binding sites was not altered by glutaraldehyde fixation. The definite polarity of plasma membranes of cultured cells express alternating surface areas charged negatively or positively.