Temperature-specific inhibition of human red cell Na+/K+ ATPase by 2,450-MHz microwave radiation.

Abstract

The ATPase activity in human red blood cell membranes was investigated in vitro as a function of temperature and exposure to 2,450-MHz continuous wave microwave radiation to confirm and extend a report of Na+ transport inhibition under certain conditions of temperature and exposure. Assays were conducted spectrophotometrically during microwave exposure with a custom-made spectrophotometer-waveguide apparatus. Temperature profiles of total ATPase and Ca+2 ATPase (ouabain-inhibited) activity between 17 and 31 degrees C were graphed as an Arrhenius plot. Each data set was fitted to two straight lines which intersect between 23 and 24 degrees C. The difference between the total and Ca+2 ATPase activities, which represented the Na+/K+ ATPase activity, was also plotted and treated similarly to yield an intersection near 25 degrees C. Exposure of membrane suspensions to electromagnetic radiation, at a dose rate of 6 W/kg and at five temperatures between 23 and 27 degrees C, resulted in an activity change only for the Na+/K+ ATPase at 25 degrees C. The activity decreased by approximately 35% compared to sham-irradiated samples. A possible explanation for the unusual temperature/microwave interaction is proposed.

AI evidence extraction

Main findings

In vitro assays of human red blood cell membranes exposed to 2,450-MHz continuous-wave microwave radiation (6 W/kg) at five temperatures (23–27°C) showed an activity change only for Na+/K+ ATPase at 25°C. At 25°C, Na+/K+ ATPase activity decreased by approximately 35% versus sham-irradiated samples; total ATPase and Ca2+ ATPase did not show reported exposure-related changes.

Outcomes measured

• Human red blood cell membrane ATPase activity (total ATPase, Ca2+ ATPase, Na+/K+ ATPase)
• Temperature dependence (Arrhenius plot intersections around 23–25°C)

Limitations

• In vitro membrane preparation; findings may not generalize to intact organisms or in vivo exposure
• Effect reported only at a single temperature point (25°C) within the tested range
• Exposure duration not stated in the abstract
• Sample size and replication details not provided in the abstract

{
    "study_type": "in_vitro",
    "exposure": {
        "band": "microwave",
        "source": null,
        "frequency_mhz": 2450,
        "sar_wkg": 6,
        "duration": null
    },
    "population": null,
    "sample_size": null,
    "outcomes": [
        "Human red blood cell membrane ATPase activity (total ATPase, Ca2+ ATPase, Na+/K+ ATPase)",
        "Temperature dependence (Arrhenius plot intersections around 23–25°C)"
    ],
    "main_findings": "In vitro assays of human red blood cell membranes exposed to 2,450-MHz continuous-wave microwave radiation (6 W/kg) at five temperatures (23–27°C) showed an activity change only for Na+/K+ ATPase at 25°C. At 25°C, Na+/K+ ATPase activity decreased by approximately 35% versus sham-irradiated samples; total ATPase and Ca2+ ATPase did not show reported exposure-related changes.",
    "effect_direction": "mixed",
    "limitations": [
        "In vitro membrane preparation; findings may not generalize to intact organisms or in vivo exposure",
        "Effect reported only at a single temperature point (25°C) within the tested range",
        "Exposure duration not stated in the abstract",
        "Sample size and replication details not provided in the abstract"
    ],
    "evidence_strength": "low",
    "confidence": 0.7399999999999999911182158029987476766109466552734375,
    "peer_reviewed_likely": "yes",
    "keywords": [
        "microwave radiation",
        "2450 MHz",
        "continuous wave",
        "SAR 6 W/kg",
        "red blood cell membranes",
        "Na+/K+ ATPase",
        "Ca2+ ATPase",
        "temperature-specific effect",
        "Arrhenius plot",
        "in vitro"
    ],
    "suggested_hubs": []
}

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