Activation-dependent and biphasic electromagnetic field effects: model based on cooperative enzyme kinetics in cellular signaling.

Bioelectromagnetics · 1996 · Mixed · Very low evidence

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MixedVery low evidencePaper 5418

Study snapshot

PublicationBioelectromagnetics · 1996

Study typereview

Reported directionMixed

Evidence ratingVery low

Abstract

Experiments on filed exposure effects of extremely-low-frequency electric and magnetic fields (EMFs) on biological systems have shown that, in many cases, the biological-functional status is of fundamental importance for an effective interaction. For example, studies of calcium uptake regulation in cells of the immune system, particularly in T lymphocytes, have revealed that, depending on the degree of cellular activation, either stimulatory, inhibitory, or no field exposure effects are observed for identical field parameters. A brief summary of the experimental findings is given, and a theoretical approach is presented that accounts in a qualitative manner for EMF exposure effects 1) that depend on the degree of cellular activation and 2) that exhibit a biphasic response behavior (stimulation/ inhibition). In the model, biochemical stimulation of the cell results in activation of specific signaling pathways that regulate calcium dynamics in the cell (calcium release from intracellular calcium stores and capacitative calcium entry). We assume that, controlled by these pathways, a specific EMF-sensitive enzyme system becomes activated. The activated enzyme, in turn, exhibits a feedback control on the signal processes, thus leading to a modulation of calcium entry. This modulation may affect other cellular processes that are calcium dependent (e.g., DNA synthesis). Magnetic field exposure is assumed to alter the kinetics of a specific step within the enzyme-reaction cycle in accord with the radical-pair mechanism, although the formulism is not restricted to this specific example. Results show that inclusion of cooperative steps within the enzyme-reaction cycle provides a theoretical basis that enables a simple description of a biphasic response behavior to EMF exposure.

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AI evidence extraction

Structured fields below were generated from the paper’s abstract and metadata to make the evidence easier to inspect. Automated extraction may be incomplete or incorrect; verify important details against the original paper.

Study typereview

Effect directionmixed

PopulationNot supplied

Sample sizeNot supplied

ExposureELF

Evidence strengthVery lowConfidence: 74% · Peer reviewed: yes

Main findings

The paper summarizes experimental findings that identical ELF electric and magnetic field parameters can produce stimulatory, inhibitory, or no effects depending on cellular activation status. It presents a qualitative theoretical model in which an EMF-sensitive enzyme system within calcium-regulating signaling pathways, including cooperative steps, can account for activation-dependent and biphasic (stimulation/inhibition) responses; magnetic field effects are discussed in relation to altered enzyme kinetics consistent with a radical-pair mechanism.

Outcomes measured

Calcium uptake regulation/modulation in immune cells (T lymphocytes)
Activation-dependent EMF response (stimulatory/inhibitory/no effect)
Biphasic response behavior (stimulation/inhibition)
Calcium-dependent cellular processes (e.g., DNA synthesis)

Limitations

Described as a brief summary and a qualitative theoretical approach rather than reporting new experimental results
Specific field parameters (frequency, intensity) and exposure duration are not provided in the abstract
Model assumptions (e.g., specific EMF-sensitive enzyme system, radical-pair mechanism) are not empirically validated within the abstract

View raw extracted JSON

{
  "study_type": "review",
  "exposure": {
    "band": "ELF",
    "source": null,
    "frequency_mhz": null,
    "sar_wkg": null,
    "duration": null
  },
  "population": null,
  "sample_size": null,
  "outcomes": [
    "Calcium uptake regulation/modulation in immune cells (T lymphocytes)",
    "Activation-dependent EMF response (stimulatory/inhibitory/no effect)",
    "Biphasic response behavior (stimulation/inhibition)",
    "Calcium-dependent cellular processes (e.g., DNA synthesis)"
  ],
  "main_findings": "The paper summarizes experimental findings that identical ELF electric and magnetic field parameters can produce stimulatory, inhibitory, or no effects depending on cellular activation status. It presents a qualitative theoretical model in which an EMF-sensitive enzyme system within calcium-regulating signaling pathways, including cooperative steps, can account for activation-dependent and biphasic (stimulation/inhibition) responses; magnetic field effects are discussed in relation to altered enzyme kinetics consistent with a radical-pair mechanism.",
  "effect_direction": "mixed",
  "limitations": [
    "Described as a brief summary and a qualitative theoretical approach rather than reporting new experimental results",
    "Specific field parameters (frequency, intensity) and exposure duration are not provided in the abstract",
    "Model assumptions (e.g., specific EMF-sensitive enzyme system, radical-pair mechanism) are not empirically validated within the abstract"
  ],
  "evidence_strength": "very_low",
  "confidence": 0.74,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "extremely-low-frequency",
    "electric fields",
    "magnetic fields",
    "EMF exposure",
    "T lymphocytes",
    "immune cells",
    "cell activation",
    "calcium signaling",
    "capacitative calcium entry",
    "intracellular calcium stores",
    "enzyme kinetics",
    "cooperativity",
    "biphasic response",
    "radical-pair mechanism",
    "DNA synthesis"
  ],
  "suggested_hubs": []
}

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AI-extracted fields are generated from the abstract and metadata and may be incomplete or incorrect. This material is for informational purposes and is not medical advice.

Identifiers and source

DOI: 10.1002/(sici)1521-186x(1996)17:6<427::aid-bem1>3.0.co;2-5
PubMed: 8986359

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