An evaluation of the biological effects of three different modes of magnetic fields on cultured mammalian cells.

Abstract

The biological effects of static magnetic fields, and their combined effects with ionizing radiation, were studied using a cultured mammalian cell line (FM3A). The three different modes of magnetic fields evaluated in this report were the 0.3 Tesla (T) field with a gradient of 0.3T/m, the 0.7T field with a gradient of 0.7T/m and the 6.34T field with no gradient. Exposure to the 0.3T and 0.7T fields had no effect on cell survival. Exposure to the 6.34T field decreased cell survival. Survival curves showing the combined effect of the 0.3T and 0.7T fields with radiation had a smaller mean lethal dose (D37) value. The survival curve of the 6.34T field was influenced by the interval between magnetic exposure and ionizing irradiation. When the interval was 6 or 12 h, the survival curve showing the combined effect of the 6.34T field had smaller D37 and quasithreshold dose (Dq) values, indicating the potentiation of the radiation effect. Flow cytometric analysis indicated that exposure to the 0.3T and 0.7T fields showed no change and that exposure to the 6.34T field showed an increase in the percentage of G1 phase cells. Our conclusions were as follows: 1) magnetic fields decreased the colony-forming abilities of cultured mammalian cells; 2) magnetic fields can affect the cell cycle; 3) a stronger magnetic field strength does not always have stronger biological effects and 4) the gradient of a magnetic field may be an important factor when combined with ionizing radiation. Despite the foregoing analysis, the biological effects of magnetic fields on mammalian cells remains a complex phenomena.

AI evidence extraction

Main findings

Exposure to 0.3 T (0.3 T/m gradient) and 0.7 T (0.7 T/m gradient) static magnetic fields had no effect on cell survival, while exposure to 6.34 T (no gradient) decreased cell survival. When combined with ionizing radiation, 0.3 T and 0.7 T exposures were associated with smaller mean lethal dose (D37) values, and for 6.34 T the combined effect depended on the interval between magnetic exposure and irradiation (6 or 12 h intervals showed smaller D37 and Dq values). Flow cytometry showed no change after 0.3 T or 0.7 T exposure, but an increased percentage of G1 phase cells after 6.34 T exposure.

Outcomes measured

• Cell survival
• Colony-forming ability
• Radiation sensitivity (D37, Dq) with ionizing radiation
• Cell cycle distribution (flow cytometry; % G1 phase)

Limitations

• Exposure duration not reported in abstract
• Sample size and replication details not reported in abstract
• In vitro cell-line model; generalizability to humans not addressed in abstract
• Details of ionizing radiation dose/rate and experimental conditions not reported in abstract

Suggested hubs

• ionizing-radiation-interactions (0.78)
  Assesses combined effects of static magnetic fields with ionizing radiation (changes in D37/Dq; interval dependence).
• static-magnetic-fields (0.72)
  Compares biological effects across multiple static magnetic field strengths and gradients in cultured mammalian cells.

{
    "study_type": "in_vitro",
    "exposure": {
        "band": null,
        "source": "static magnetic field",
        "frequency_mhz": null,
        "sar_wkg": null,
        "duration": null
    },
    "population": "Cultured mammalian cell line (FM3A)",
    "sample_size": null,
    "outcomes": [
        "Cell survival",
        "Colony-forming ability",
        "Radiation sensitivity (D37, Dq) with ionizing radiation",
        "Cell cycle distribution (flow cytometry; % G1 phase)"
    ],
    "main_findings": "Exposure to 0.3 T (0.3 T/m gradient) and 0.7 T (0.7 T/m gradient) static magnetic fields had no effect on cell survival, while exposure to 6.34 T (no gradient) decreased cell survival. When combined with ionizing radiation, 0.3 T and 0.7 T exposures were associated with smaller mean lethal dose (D37) values, and for 6.34 T the combined effect depended on the interval between magnetic exposure and irradiation (6 or 12 h intervals showed smaller D37 and Dq values). Flow cytometry showed no change after 0.3 T or 0.7 T exposure, but an increased percentage of G1 phase cells after 6.34 T exposure.",
    "effect_direction": "mixed",
    "limitations": [
        "Exposure duration not reported in abstract",
        "Sample size and replication details not reported in abstract",
        "In vitro cell-line model; generalizability to humans not addressed in abstract",
        "Details of ionizing radiation dose/rate and experimental conditions not reported in abstract"
    ],
    "evidence_strength": "low",
    "confidence": 0.7399999999999999911182158029987476766109466552734375,
    "peer_reviewed_likely": "yes",
    "keywords": [
        "static magnetic field",
        "Tesla",
        "magnetic field gradient",
        "FM3A cells",
        "cell survival",
        "colony-forming ability",
        "ionizing radiation",
        "D37",
        "Dq",
        "cell cycle",
        "flow cytometry"
    ],
    "suggested_hubs": [
        {
            "slug": "ionizing-radiation-interactions",
            "weight": 0.7800000000000000266453525910037569701671600341796875,
            "reason": "Assesses combined effects of static magnetic fields with ionizing radiation (changes in D37/Dq; interval dependence)."
        },
        {
            "slug": "static-magnetic-fields",
            "weight": 0.7199999999999999733546474089962430298328399658203125,
            "reason": "Compares biological effects across multiple static magnetic field strengths and gradients in cultured mammalian cells."
        }
    ]
}

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