Effect of microwave radiation on cells treated with membrane-injuring substances.

Abstract

WISH cells grown in vitro were pretreated with subcytotoxic concentrations of digitonin, cortisol and purified bacterial toxins -- staphylococcal beta-haemolysin or Clostridium perfringens alpha-toxin and irradiated with 3 GHz electromagnetic wave (microwaves) at the field power densities 5 or 40 mW/cm2. At 40 mW/cm2 increase in temperature of the culture medium of about 2-3 degrees C was noted, while at 5 mW/cm2 no detectable increase in temperature was found. Control and pretreated WISH cells after irradiation in the microwave field were used for evaluation of their viability, incorporation of tritiated thymidine, glycine and uridine and level of intracellular cyclic AMP. Irradiation with microwaves resulted in lowering of thymidine and glycine incorporation along with changes in the intracellular amount of cAMP (decrease in cells exposed to 5 mW/cm2 and increase in those exposed to 40 mW/cm2). Under both conditions viability of the cultures was normal. Pretreatment of cells with digitonin or purified bacterial toxins followed by irradiation with microwaves resulted in enhancement of the cytotoxic effect with lowering of cell viability, especially after exposition to power density of 40 mW/cm2. Cortisol led to decrease in 3H-glycine and 3H-uridine incorporation into WISH cells, but did not influence the reaction of the cells to microwave radiation. In view of the results presented it may be concluded that substances injuring cell membranes sensitize cell cultures to electromagnetic radiation of the microwave range and may enhance the specific (non-thermal) effect of microwaves.

AI evidence extraction

Main findings

WISH cells irradiated at 3 GHz (5 or 40 mW/cm2) showed reduced thymidine and glycine incorporation and changes in intracellular cAMP (decrease at 5 mW/cm2; increase at 40 mW/cm2) while viability remained normal without pretreatment. Pretreatment with digitonin or purified bacterial toxins followed by microwave irradiation enhanced cytotoxicity and reduced viability, especially at 40 mW/cm2; cortisol decreased glycine and uridine incorporation but did not alter the response to microwave irradiation.

Outcomes measured

• Cell viability
• Incorporation of tritiated thymidine
• Incorporation of tritiated glycine
• Incorporation of tritiated uridine
• Intracellular cyclic AMP (cAMP) level
• Culture medium temperature change

Limitations

• No sample size reported in abstract
• Exposure duration not reported
• SAR not reported; exposure characterized by power density only
• Temperature increase occurred at 40 mW/cm2 (2–3°C), complicating separation of thermal vs non-thermal effects
• In vitro model (WISH cells) may not generalize to in vivo/human outcomes

{
    "study_type": "in_vitro",
    "exposure": {
        "band": "microwave",
        "source": null,
        "frequency_mhz": 3000,
        "sar_wkg": null,
        "duration": null
    },
    "population": "WISH cells grown in vitro",
    "sample_size": null,
    "outcomes": [
        "Cell viability",
        "Incorporation of tritiated thymidine",
        "Incorporation of tritiated glycine",
        "Incorporation of tritiated uridine",
        "Intracellular cyclic AMP (cAMP) level",
        "Culture medium temperature change"
    ],
    "main_findings": "WISH cells irradiated at 3 GHz (5 or 40 mW/cm2) showed reduced thymidine and glycine incorporation and changes in intracellular cAMP (decrease at 5 mW/cm2; increase at 40 mW/cm2) while viability remained normal without pretreatment. Pretreatment with digitonin or purified bacterial toxins followed by microwave irradiation enhanced cytotoxicity and reduced viability, especially at 40 mW/cm2; cortisol decreased glycine and uridine incorporation but did not alter the response to microwave irradiation.",
    "effect_direction": "mixed",
    "limitations": [
        "No sample size reported in abstract",
        "Exposure duration not reported",
        "SAR not reported; exposure characterized by power density only",
        "Temperature increase occurred at 40 mW/cm2 (2–3°C), complicating separation of thermal vs non-thermal effects",
        "In vitro model (WISH cells) may not generalize to in vivo/human outcomes"
    ],
    "evidence_strength": "low",
    "confidence": 0.7800000000000000266453525910037569701671600341796875,
    "peer_reviewed_likely": "yes",
    "keywords": [
        "microwave radiation",
        "3 GHz",
        "power density",
        "WISH cells",
        "digitonin",
        "cortisol",
        "staphylococcal beta-haemolysin",
        "Clostridium perfringens alpha-toxin",
        "membrane injury",
        "cytotoxicity",
        "thymidine incorporation",
        "glycine incorporation",
        "uridine incorporation",
        "cAMP"
    ],
    "suggested_hubs": []
}

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