Metabolic effects of microwave radiation and convection heating on human mononuclear leukocytes.

Abstract

The effects of microwave radiation (2450 MHz, continuous wave, mean specific absorption rate of 103.5 +/- 4.2 W/kg) and convection heating on the nonphosphorylating oxidative metabolism of human peripheral mononuclear leukocytes (96% lymphocytes, 4% monocytes) at 37 degrees C were investigated. Metabolic activity, determined by chemiluminescence (CL) of cells challenged with luminol (5-amino-2,3-dihydro-1,4-phthalazinedione) linked to bovine serum albumin, was detected with a brightness photometer. A significant stimulation after microwave exposure (p less than 0.005) over total CL of matched 37 degrees C incubator controls was observed. A similar degree of stimulation compared to incubator controls was also detected after sham treatment. There was no significant difference between changes in total CL or stimulation indices of the microwave and sham exposed groups. It appears that exposure to microwave radiation, under normothermic (37 +/- 0.03 degrees C) conditions, has no effect on the oxidative metabolic activity of human peripheral mononuclear leukocytes. However, the significant differences between microwave or sham exposed cells and their respective incubator controls occurred because the temperature of the incubator controls did not exceed 35.9 degrees C and this temperature required 39 minutes to reach from 22 degrees C. Slow heating of incubator controls must be accounted for in thermal and radiofrequency radiation studies in vitro.

AI evidence extraction

Main findings

Microwave exposure (2450 MHz continuous wave; mean SAR 103.5 ± 4.2 W/kg) produced a significant stimulation versus incubator controls, but a similar stimulation was also observed after sham treatment. There was no significant difference between microwave- and sham-exposed groups, and the authors attribute differences versus incubator controls to slower heating of the incubator controls (not exceeding 35.9°C).

Outcomes measured

• Nonphosphorylating oxidative metabolism
• Chemiluminescence (luminol-linked BSA) response / metabolic activity

Limitations

• Incubator controls warmed slowly and did not reach the target temperature (did not exceed 35.9°C), potentially confounding comparisons with microwave/sham conditions.
• Exposure duration not reported in the abstract.
• Sample size not reported in the abstract.

{
    "study_type": "in_vitro",
    "exposure": {
        "band": "microwave",
        "source": null,
        "frequency_mhz": 2450,
        "sar_wkg": 103.5,
        "duration": null
    },
    "population": "Human peripheral mononuclear leukocytes (96% lymphocytes, 4% monocytes)",
    "sample_size": null,
    "outcomes": [
        "Nonphosphorylating oxidative metabolism",
        "Chemiluminescence (luminol-linked BSA) response / metabolic activity"
    ],
    "main_findings": "Microwave exposure (2450 MHz continuous wave; mean SAR 103.5 ± 4.2 W/kg) produced a significant stimulation versus incubator controls, but a similar stimulation was also observed after sham treatment. There was no significant difference between microwave- and sham-exposed groups, and the authors attribute differences versus incubator controls to slower heating of the incubator controls (not exceeding 35.9°C).",
    "effect_direction": "no_effect",
    "limitations": [
        "Incubator controls warmed slowly and did not reach the target temperature (did not exceed 35.9°C), potentially confounding comparisons with microwave/sham conditions.",
        "Exposure duration not reported in the abstract.",
        "Sample size not reported in the abstract."
    ],
    "evidence_strength": "low",
    "confidence": 0.7399999999999999911182158029987476766109466552734375,
    "peer_reviewed_likely": "yes",
    "keywords": [
        "microwave radiation",
        "2450 MHz",
        "continuous wave",
        "specific absorption rate",
        "SAR",
        "convection heating",
        "in vitro",
        "human mononuclear leukocytes",
        "lymphocytes",
        "monocytes",
        "oxidative metabolism",
        "chemiluminescence",
        "luminol",
        "temperature control",
        "sham exposure"
    ],
    "suggested_hubs": []
}

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