Modification of membrane fluidity in melanin-containing cells by low-level microwave radiation.

Bioelectromagnetics · 1992 · Harm · Low evidence

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HarmLow evidencePaper 6301

Study snapshot

PublicationBioelectromagnetics · 1992

Study typein_vitro

Reported directionHarm

Evidence ratingLow

Abstract

The treatment of a B16 melanoma cell line with 2.45-GHz pulsed microwaves (10 mW/cm2, 10-microseconds pulses at 100 pps, 1-h exposure; SAR, 0.2 W/kg) resulted in changes of membrane ordering as measured by EPR (electron paramagnetic resonance) reporter techniques. The changes reflected a shift from a more fluid-like phase to a more solid (ordered) state of the cell membrane. Exposure of artificially prepared liposomes that were reconstituted with melanin produced similar results. In contrast, neither B16 melanoma cells treated with 5-Bromo-2-Deoxyuridine (3 micrograms/day x 7 days) to render them amelanotic, nor liposomes prepared without melanin, exhibited the microwave-facilitated increase of ordering. Inhibition of the ordering was achieved by the use of superoxide dismutase (SOD), which strongly implicates oxygen radicals as a cause of the membrane changes. The data indicate that a significant, specific alteration of cell-membrane ordering followed microwave exposure. This alteration was unique to melanotic membranes and was due, at least in part, to the generation of oxygen radicals.

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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 typein_vitro

Effect directionharm

PopulationB16 melanoma cell line; artificially prepared liposomes (with/without melanin)

Sample sizeNot supplied

Exposuremicrowave · 2450 MHz · 0.2 W/kg · 1-h exposure; 10-microseconds pulses at 100 pps

Evidence strengthLowConfidence: 86% · Peer reviewed: yes

Main findings

Exposure of B16 melanoma cells to 2.45-GHz pulsed microwaves (10 mW/cm2; SAR 0.2 W/kg; 1 h) was associated with increased membrane ordering (shift toward a more solid/ordered state) measured by EPR. Similar ordering changes occurred in melanin-reconstituted liposomes, while amelanotic B16 cells and liposomes without melanin did not show the effect. Superoxide dismutase inhibited the ordering change, implicating oxygen radicals in the observed membrane effects.

Outcomes measured

Cell membrane ordering/fluidity (EPR reporter techniques)
Microwave-facilitated increase of membrane ordering
Role of oxygen radicals (inhibition by superoxide dismutase)

Limitations

Sample size not reported in abstract
In vitro model (cell line and liposomes); generalizability to humans not addressed
Exposure conditions are specific (2.45 GHz pulsed microwaves; SAR 0.2 W/kg) and may not represent typical real-world exposures

View raw extracted JSON

{
  "study_type": "in_vitro",
  "exposure": {
    "band": "microwave",
    "source": null,
    "frequency_mhz": 2450,
    "sar_wkg": 0.2,
    "duration": "1-h exposure; 10-microseconds pulses at 100 pps"
  },
  "population": "B16 melanoma cell line; artificially prepared liposomes (with/without melanin)",
  "sample_size": null,
  "outcomes": [
    "Cell membrane ordering/fluidity (EPR reporter techniques)",
    "Microwave-facilitated increase of membrane ordering",
    "Role of oxygen radicals (inhibition by superoxide dismutase)"
  ],
  "main_findings": "Exposure of B16 melanoma cells to 2.45-GHz pulsed microwaves (10 mW/cm2; SAR 0.2 W/kg; 1 h) was associated with increased membrane ordering (shift toward a more solid/ordered state) measured by EPR. Similar ordering changes occurred in melanin-reconstituted liposomes, while amelanotic B16 cells and liposomes without melanin did not show the effect. Superoxide dismutase inhibited the ordering change, implicating oxygen radicals in the observed membrane effects.",
  "effect_direction": "harm",
  "limitations": [
    "Sample size not reported in abstract",
    "In vitro model (cell line and liposomes); generalizability to humans not addressed",
    "Exposure conditions are specific (2.45 GHz pulsed microwaves; SAR 0.2 W/kg) and may not represent typical real-world exposures"
  ],
  "evidence_strength": "low",
  "confidence": 0.86,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "microwave radiation",
    "2.45 GHz",
    "pulsed microwaves",
    "SAR",
    "membrane fluidity",
    "membrane ordering",
    "EPR",
    "melanin",
    "B16 melanoma",
    "liposomes",
    "oxygen radicals",
    "superoxide dismutase"
  ],
  "suggested_hubs": [
    {
      "slug": "mechanisms-oxidative-stress",
      "weight": 0.9,
      "reason": "SOD inhibition implicates oxygen radicals as a mechanism for membrane changes after microwave exposure."
    },
    {
      "slug": "rf-microwave-in-vitro",
      "weight": 0.85,
      "reason": "In vitro exposure of cells/liposomes to 2.45 GHz microwaves with reported SAR and membrane effects."
    }
  ]
}

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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.2250130207
PubMed: 1317176

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