Effects of time delays on biological feedback systems and electromagnetic field exposures

2018 · Unclear · Insufficient evidence

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UnclearInsufficient evidencePaper 2170

Study snapshot

Publicationmanual · 2018

Study typereview

Reported directionUnclear

Evidence ratingInsufficient

Abstract

Effects of time delays on biological feedback systems and electromagnetic field exposures Barnes F, Kandala S. Effects of time delays on biological feedback systems and electromagnetic field exposures. Bioelectromagnetics. 2018 Feb 19. doi: 10.1002/bem.22114. No Abstract ncbi.nlm.nih.gov Excerpts Biological systems contain a large number of signaling pathway and amplifying systems. Often these signaling systems operate in parallel and include both feedback and feed forward signals. An extensive review of how feedback loops shape cellular signals in space and time is presented by Brandman and Meyer [2008]. There are over 3,000 signaling proteins and over 15 s messengers that lead to hundreds of cell-specific signaling systems. These multiple feedback loops lead to a wide variety of responses including oscillations, bi-stability, and system stabilization. The multiple feedback loops often make it hard to separate cause and effect. Changes in concentrations of ROS molecules have been shown to have a wide range of both positive and negative effects on biological systems [Halliwell and Gutteridge, 2015]. Early works on the exposures of biological systems to microwaves show that even when the biological system was held at constant temperatures, there were changes in membrane resistance that differed from the first exposures to the second, and there was a time delay in the response [Arber and Lin, 1985a,b]. More recent works show that magnetic fields have been shown to modify ROS concentrations [Georgiou, 2010; Castello et al., 2014; Usselman et al., 2014, 2016]. We can expect signals such as modulated sine waves or pulses at different repetition rates containing more than one frequency to modify more than one biological process. Overall, we know that there are many feedback and repair processes in biological systems. These feedback processes occur with time delays following a stimulus, and thus we can expect that the timing of a periodic stimulus can either lead to an amplified or attenuated response. Additionally, we can expect the responses of biological systems to be frequency-dependent. With knowledge of time constants for various biological and medical responses, we may be able to signal the systems to increase or decrease such things as cell growth rates or immune responses.

Machine Enhanced Logic

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 directionunclear

PopulationNot supplied

Sample sizeNot supplied

Exposuremicrowave

Evidence strengthInsufficientConfidence: 56% · Peer reviewed: yes

Main findings

The paper discusses how time delays in biological feedback and repair processes could lead periodic stimuli (including EMF signals) to produce amplified or attenuated responses and suggests responses may be frequency-dependent. It cites prior studies reporting delayed membrane resistance changes under microwave exposure at constant temperature and reports that magnetic fields have been shown to modify ROS concentrations in more recent work.

Outcomes measured

cellular signaling/feedback dynamics (time delays, oscillations, bistability, stabilization)
membrane resistance changes (reported in early microwave exposure work)
reactive oxygen species (ROS) concentration changes (reported in magnetic field studies)
frequency-dependent biological responses (conceptual)

Limitations

No abstract provided; information is from excerpts only.
No specific exposure parameters (frequency, intensity/SAR, duration) are provided in the excerpts.
No population, sample size, or quantitative effect estimates are reported in the provided text.
Statements include expectations/hypotheses and citations to other work rather than clearly described original experimental results.

View raw extracted JSON

{
  "study_type": "review",
  "exposure": {
    "band": "microwave",
    "source": null,
    "frequency_mhz": null,
    "sar_wkg": null,
    "duration": null
  },
  "population": null,
  "sample_size": null,
  "outcomes": [
    "cellular signaling/feedback dynamics (time delays, oscillations, bistability, stabilization)",
    "membrane resistance changes (reported in early microwave exposure work)",
    "reactive oxygen species (ROS) concentration changes (reported in magnetic field studies)",
    "frequency-dependent biological responses (conceptual)"
  ],
  "main_findings": "The paper discusses how time delays in biological feedback and repair processes could lead periodic stimuli (including EMF signals) to produce amplified or attenuated responses and suggests responses may be frequency-dependent. It cites prior studies reporting delayed membrane resistance changes under microwave exposure at constant temperature and reports that magnetic fields have been shown to modify ROS concentrations in more recent work.",
  "effect_direction": "unclear",
  "limitations": [
    "No abstract provided; information is from excerpts only.",
    "No specific exposure parameters (frequency, intensity/SAR, duration) are provided in the excerpts.",
    "No population, sample size, or quantitative effect estimates are reported in the provided text.",
    "Statements include expectations/hypotheses and citations to other work rather than clearly described original experimental results."
  ],
  "evidence_strength": "insufficient",
  "confidence": 0.56,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "time delays",
    "biological feedback systems",
    "signaling pathways",
    "microwaves",
    "magnetic fields",
    "ROS",
    "membrane resistance",
    "frequency dependence",
    "modulated signals",
    "pulses"
  ],
  "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/bem.22114
PubMed: Not supplied

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