Influence of electromagnetic fields on the efflux of calcium ions from brain tissue in vitro: a three-model analysis consistent with the frequency response up to 510 Hz

Abstract

The frequency dependence of electromagnetic field-induced calcium-ion efflux from chicken brain tissues has been examined at 15-Hz intervals over the range 1-510 Hz. The electric field component was 15 Vrms/m and the magnetic component varied between 59 and 69 nTrms. No patterns of response as a function of frequency could be readily discerned when the differences in mean efflux values between exposed and sham samples were compared. However, the calculated P-value, a function that combines at each frequency the difference between the means of the exposed and sham groups with the variance of each group, does provide a basis for hypothesizing the existence of three frequency-dependent patterns in the data. One pattern includes all the highly significant (P less than .01) responses which occur between 15 and 315 Hz, at 30-Hz intervals; two independent trials at 165 Hz, giving nonsignificant responses (P greater than .5), break this pattern into two groups of five frequencies each, which is contrary to the expected result for a simple Lorentz-force interaction. However, another pattern of significant results at 60, 90, and 180 Hz, but not at 300 Hz, is consistent with a Lorentz-force model. A third pattern, composed of only one significant response at 405 Hz, is very close to the resonance predicted on a linear extrapolation from high-frequency data for 13carbon atoms. This hypothetical ordering of the frequency-response profile provides the basis for future experimental designs to test each possible interaction model and for their connection to the calcium-ion efflux endpoint.

AI evidence extraction

Main findings

Calcium-ion efflux from chicken brain tissues was examined across 1–510 Hz (15-Hz intervals) with 15 Vrms/m electric field and 59–69 nTrms magnetic field. Differences in mean efflux between exposed and sham samples did not show readily discernible frequency-response patterns, but analyses of calculated P-values were used to hypothesize three possible frequency-dependent patterns, including significant responses (P<.01) at some frequencies (e.g., at 30-Hz intervals between 15 and 315 Hz with exceptions at 165 Hz; significant results at 60, 90, and 180 Hz but not 300 Hz; and one significant response at 405 Hz).

Outcomes measured

• Calcium-ion efflux from brain tissue

Limitations

• No clear frequency-response pattern was discernible from differences in mean efflux values between exposed and sham samples.
• Frequency-response patterns were described as hypothesized based on calculated P-values rather than directly evident from mean differences.
• Sample size and exposure duration were not reported in the abstract.

Suggested hubs

• elf-emf (0.9)
  In vitro study of extremely low frequency (1–510 Hz) electromagnetic fields and a biological endpoint (calcium efflux).

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    "population": "Chicken brain tissues (in vitro)",
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    "outcomes": [
        "Calcium-ion efflux from brain tissue"
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    "main_findings": "Calcium-ion efflux from chicken brain tissues was examined across 1–510 Hz (15-Hz intervals) with 15 Vrms/m electric field and 59–69 nTrms magnetic field. Differences in mean efflux between exposed and sham samples did not show readily discernible frequency-response patterns, but analyses of calculated P-values were used to hypothesize three possible frequency-dependent patterns, including significant responses (P<.01) at some frequencies (e.g., at 30-Hz intervals between 15 and 315 Hz with exceptions at 165 Hz; significant results at 60, 90, and 180 Hz but not 300 Hz; and one significant response at 405 Hz).",
    "effect_direction": "mixed",
    "limitations": [
        "No clear frequency-response pattern was discernible from differences in mean efflux values between exposed and sham samples.",
        "Frequency-response patterns were described as hypothesized based on calculated P-values rather than directly evident from mean differences.",
        "Sample size and exposure duration were not reported in the abstract."
    ],
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    "keywords": [
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        "frequency dependence",
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        "chicken brain tissue",
        "in vitro",
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}

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