Effect of hyperthermia on rabbit macrophages.

The effect of water-bath hyperthermia on rabbit peritoneal macrophages was studied in vitro. The cells were exposed to hyperthermia for 30 min to 4 hours and membrane transport of ions as measured by total and ouabain-inhibited 86Rb influx as well as membrane permeability for 86Rb and 51Cr-labelled intracellular proteins were investigated. Heat-treated macrophages were tested for their ability to phagocyte staphylococci and for reduction of nitroblue-tetrazolium. Moreover the effect of microwave whole-body hyperthermia on rabbit phogocytic cells was studied in vivo. Ion transport to macrophages was stimulated by both intensive (43 degrees C) and moderate (40 degrees C) hyperthermia. On the other hand exposition of the cells to 43 degrees C led to pronounced release of 86Rb and 51Cr from prelabelled cells. NBT reduction was generally decreased in macrophages exposed to 43 degrees C and increased in macrophages kept at 40 degrees C. Clearance of 32P-labelled staphylococci from peripheral blood of microwave-irradiated rabbits diminished when animals were exposed to microwave hyperthermia for f or 7 days (2 hours daily).

The search for an influence of whole-body microwave hyperthermia on anti-tumor immunity.

The effect of microwave whole-body hyperthermia was examined on the takes of tumor after i.v. administration of the tumor single cell suspension. It was shown that the longer the exposure to hyperthermia treatment the higher the number of lung nodules obtained by injection of the same dose of tumor cells. Also, the expression of contact hypersenstivity to oxazolone was strongly inhibited after hyperthermia treatment. It was documented that it is possible to transfer the diminished resistance to tumor with bone marrow, whereas impaired responsiveness to oxazolone was transferred with spleen cells or thymocytes.

Effect of whole-body microwave hyperthermia on delayed cutaneous hypersensitivity in tumor-bearing mice.

Tumor-bearing and normal BALB/c mice were examined for their responsiveness to contact-sensitizing agent oxazolone after whole-body microwave hyperthermia treatment. The effective therapy with hyperthermia prolonging mean survival time of the animals and causing tumors regression resulted in strongly pronounced hyporeactivity to oxazolone. The impaired responsiveness remained unchanged until death of the tumor-bearing animals. In the case of tumor-free animals delayed cutaneous response returned to normal values within 8-12 days after hyperthermia treatment. It is documented that the longer exposure to hyperthermia sessions the more pronounced depression of reactivity to oxazolone occurs.

Acceleration of the development of benzopyrene-induced skin cancer in mice by microwave radiation.

Development and growth of skin cancer may be affected by various physical and chemical factors present in human environment. Of these factors electromagnetic radiation of radio- and microwave spectra are among the most common. In the present study Balb/c mice were exposed to chemical carcinogen, 3,4-benzopyrene, painted on the skin every 2nd day for a total of 6 months, and simultaneously irradiated with athermal (5 mW/cm2) or subthermal (15 mW/cm2) doses of 2,450 MHz microwaves. The other group of animals was preirradiated with microwaves at 10 mW/cm2 power level for 1, 2, or 3 months and then treated with benzopyrene, as above. Control mice were exposed for 6 months to benzopyrene, resulting in the development of baso- or spinocellular skin carcinoma within approximately 9 months, and sham-irradiated with microwaves. The growth of the tumour was assessed according to a self-designed 7-range macroscopic scale, supported by microscopical examinations of skin sections. All protocols of microwave irradiations resulted in a significant acceleration of the development of benzopyrene-induced skin cancer and in shortening of life span of the tumour-bearing hosts. This effect seemed to be dose-dependent since subthermal doses (15 mV/cm2) and longer (3 months) expositions to microwaves were more efficient as compared to athermal doses (5 mW/cm2) and shorter preirradiations. In addition, low-level, long-lasting exposure to microwaves led to a marked suppression of delayed hypersensitivity of mice treated with benzopyrene, as assessed by their reactivity to dinitrofluorbenzene (DNFB). It is suggested that the observed co-carcinogenic effect of microwave radiation may, at least in part, result from the inhibitory action of microwaves on cellular immune reactions of exposed animals.

Serum cytokine levels (IL-4, IL-6, IL-8, G-CSF, GM-CSF) in burned patients.

The presence and concentration of selected cytokines (interleukin 4 (IL-4), interleukin 6 (IL-6), interleukin 8 (IL-8), granulocyte colony-stimulating factor (G-CSF) and granulocyte-macrophage colony-stimulating factor (GM-CSF) were evaluated in the sera of 12 burned patients (6-90 per cent body surface area). The presence of cytokines in the sera of 20 healthy volunteers (control group) was always undetectable (< 2 pg/ml). In sera of the burned patients the concentrations of IL-4 or GM-CSF were also below the test sensitivity levels, while G-CSF and IL-6 were present throughout all the observation period and IL-8 was detectable at the onset of massive infections. The serum concentrations of G-CSF and IL-6 increased during the episodes of clinically and bacteriologically detectable infections. Their increases were, however, observable 12-24 h later than the other infection symptoms. Similar increases in G-CSF and IL-6 levels have been detected during corrective surgery (covering of granulation tissue with skin grafts). It may be concluded that serum G-CSF and IL-6 levels in burned patients may be considered as diagnostic factors, but the delays in the reaction to the massive infection do not allow us to use them for predicting the time of onset of the infection.

Does whole-body hyperthermia therapy involve participation of the immune system?

The effect of micro-wave whole-body hyperthermia on tumor growth and lung metastasis counts was examined in adult BALB/c mice. The effective therapy with hyperthermia prolonging mean survival time of the animals and causing tumor regression resulted in concimitant depression of anti-tumor immunity measured in vivo. The beneficial effect of preimmunization of animals with killed tumor cells on subsequent challenge with live tumor cells was completely abrogated by hyperthermia treatment. It is postulated that this form of therapy is directly related only to heat sensitivity of tumor cells and that there is no profitable participation of the immune system in the anti-tumor effect of wholebody hyperthermia.

Effect of three strains of propionibacteria (P. granulosum, P. avidum, P. acnes) and cell-wall preparations on lymphocytes and macrophages.

The effect of the strains of Propionibacteria (P. granulosum, P. avidum, P. acnes) on functional and metabolic activities of mouse lymphocytes and rabbit macrophages was examined in vivo and in vitro. In some of the experiments bacterial cell walls isolated from the above bacteria were tested and compared with the activity of whole bacteria. In isolated lymph-node lymphocytes influx of 86Rb and its inhibition by ouabaine, release of 86Rb and 51Cr from prelabelled cells, as well as spontaneous and PHA-stimulated incorporation of 3H-uridine were tested after treatment with 10 or 50 microgram/ml of Propionibacteria (whole cells or cell walls). Phagocytosis of 32P-labelled Staphylococci and reduction of Nitro-BT were examined in isolated rabbit peritoneal macrophages treated with the above concentrations of Propionibacteria. Clearance of 32P-labelled Staphylococci from peripheral blood in rabbits treated with 5 mg per kg body weight of Propionibacteria was also studied. All three strains of Propionibacteriae stimulated 86Rb influx into lymphocytes, the effect being observed only in concentrations leading to parallel increase of 86Rb and 51Cr release from prelabelled cells. No significant differences in activity between the three tested strains of bacteriae were found. Propionibacteria of a dosage of 50 microgram/ml significantly increased spontaneous and PHA-stimulated incorporation of 3H-uridine into lymphocytes. All three strains of Propionibacteria markedly stimulated both phagocytosis and intracellular digestion (as measured by the ability to reduce Nitro-BT) in isolated peritoneal macrophages. This was accompanied by faster clearance of Staphylococci from peripheral blood of rabbits treated with 5 mg per kg body weight of Propionibacteriae. The obtained results showed direct stimulation of lymphocytic and macrophagic functional activity by whole cells and isolated cell walls of all three tested strains of Propionibacteria.