915 MHz microwaves and 50 Hz magnetic field affect chromatin conformation and 53BP1 foci in human lymphocytes from hypersensitive and healthy persons.

Bioelectromagnetics · 2005 · Mixed · Low evidence

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MixedLow evidencePaper 5197

Study snapshot

PublicationBioelectromagnetics · 2005

Study typerandomized_trial

Reported directionMixed

Evidence ratingLow

Abstract

We used exposure to microwaves from a global system for mobile communication (GSM) mobile phone (915 MHz, specific absorption rate (SAR) 37 mW/kg) and power frequency magnetic field (50 Hz, 15 muT peak value) to investigate the response of lymphocytes from healthy subjects and from persons reporting hypersensitivity to electromagnetic field (EMF). The hypersensitive and healthy donors were matched by gender and age and the data were analyzed blind to treatment condition. The changes in chromatin conformation were measured with the method of anomalous viscosity time dependencies (AVTD). 53BP1 protein, which has been shown to colocalize in foci with DNA double strand breaks (DSBs), was analyzed by immunostaining in situ. Exposure at room temperature to either 915 MHz or 50 Hz resulted in significant condensation of chromatin, shown as AVTD changes, which was similar to the effect of heat shock at 41 degrees C. No significant differences in responses between normal and hypersensitive subjects were detected. Neither 915 MHz nor 50 Hz exposure induced 53BP1 foci. On the contrary, a distinct decrease in background level of 53BP1 signaling was observed upon these exposures as well as after heat shock treatments. This decrease correlated with the AVTD data and may indicate decrease in accessibility of 53BP1 to antibodies because of stress-induced chromatin condensation. Apoptosis was determined by morphological changes and by apoptotic fragmentation of DNA as analyzed by pulsed-field gel electrophoresis (PFGE). No apoptosis was induced by exposure to 50 Hz and 915 MHz microwaves. In conclusion, 50 Hz magnetic field and 915 MHz microwaves under specified conditions of exposure induced comparable responses in lymphocytes from healthy and hypersensitive donors that were similar but not identical to stress response induced by heat shock.

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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 typerandomized_trial

Effect directionmixed

PopulationHuman lymphocytes from healthy subjects and from persons reporting hypersensitivity to EMF (donors matched by gender and age)

Sample sizeNot supplied

ExposureRF · 915 MHz · 0.037 W/kg

Evidence strengthLowConfidence: 74% · Peer reviewed: yes

Main findings

Exposure to either 915 MHz GSM mobile phone microwaves (SAR 37 mW/kg) or a 50 Hz magnetic field (15 µT peak) at room temperature resulted in significant chromatin condensation (AVTD changes), similar to heat shock at 41°C. No significant differences were detected between hypersensitive and healthy donors. Neither exposure induced 53BP1 foci or apoptosis; instead, a decrease in background 53BP1 signaling was observed and correlated with chromatin condensation.

Outcomes measured

Chromatin conformation (anomalous viscosity time dependencies; AVTD)
53BP1 foci/signaling (immunostaining in situ; marker associated with DNA double strand breaks)
Apoptosis (morphology; DNA fragmentation by PFGE)

Limitations

Sample size not reported in the abstract
Exposure duration not reported in the abstract
Study details on randomization/allocation not described in the abstract (only blinding to treatment condition is stated)
Outcomes are cellular/biomarker endpoints in isolated lymphocytes; clinical relevance not established in the abstract

View raw extracted JSON

{
  "study_type": "randomized_trial",
  "exposure": {
    "band": "RF",
    "source": "mobile phone",
    "frequency_mhz": 915,
    "sar_wkg": 0.037,
    "duration": null
  },
  "population": "Human lymphocytes from healthy subjects and from persons reporting hypersensitivity to EMF (donors matched by gender and age)",
  "sample_size": null,
  "outcomes": [
    "Chromatin conformation (anomalous viscosity time dependencies; AVTD)",
    "53BP1 foci/signaling (immunostaining in situ; marker associated with DNA double strand breaks)",
    "Apoptosis (morphology; DNA fragmentation by PFGE)"
  ],
  "main_findings": "Exposure to either 915 MHz GSM mobile phone microwaves (SAR 37 mW/kg) or a 50 Hz magnetic field (15 µT peak) at room temperature resulted in significant chromatin condensation (AVTD changes), similar to heat shock at 41°C. No significant differences were detected between hypersensitive and healthy donors. Neither exposure induced 53BP1 foci or apoptosis; instead, a decrease in background 53BP1 signaling was observed and correlated with chromatin condensation.",
  "effect_direction": "mixed",
  "limitations": [
    "Sample size not reported in the abstract",
    "Exposure duration not reported in the abstract",
    "Study details on randomization/allocation not described in the abstract (only blinding to treatment condition is stated)",
    "Outcomes are cellular/biomarker endpoints in isolated lymphocytes; clinical relevance not established in the abstract"
  ],
  "evidence_strength": "low",
  "confidence": 0.74,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "915 MHz",
    "GSM",
    "mobile phone",
    "50 Hz",
    "magnetic field",
    "human lymphocytes",
    "electromagnetic hypersensitivity",
    "chromatin conformation",
    "AVTD",
    "53BP1",
    "DNA double strand breaks",
    "apoptosis",
    "PFGE",
    "heat shock"
  ],
  "suggested_hubs": [
    {
      "slug": "who-icnirp",
      "weight": 0.2,
      "reason": "Study examines biological effects of RF and ELF exposures relevant to EMF health risk discussions."
    }
  ]
}

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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.20103
PubMed: 15768430

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