Microwave radiation enhances teratogenic effect of cytosine arabinoside in mice.

Abstract

Impregnated Swiss mice were irradiated 2 h daily on days 1-18 of gestation in nonthermal (1 or 10 mW/cm2) or thermogenic (40 mW/cm2) 2,450-MHz microwave (MW) fields. On the 19th day of pregnancy all dams were killed to check the number of resorptions. Living fetuses were isolated, weighed and checked for the presence of macroscopically visible malformations of skeleton and cleft palate (CP) and/or lip (CLP). Some of the pregnant mice in each group were injected intraperitoneally on the 9th day of gestation with 10 mg/kg of cytosine arabinoside (ara-C), a well-known teratogen resulting under the above conditions in the appearance of about 15% (42 of 354) of resorbed implantation points and the development of CP or CLP in about 30% (96 of 312) of fetuses. Exposure to nonthermal MW fields during pregnancy did not lead to resorptions or detectable malformations; however, the body mass of 19-day fetuses was significantly lower than in sham-irradiated controls. MW hyperthermia (40 mW/cm2) applied during pregnancy led to an increased number of resorptions - about 25% (37 of 157) compared to 2% (6 of 306) in controls. Significant enhancement of the teratogenic potency of ara-C was observed after combined exposure to both ara-C and MWs during pregnancy. In dams treated with ara-C alone about 20% (62 of 358) resorptions and about 30% (91 of 296) fetuses with CL or CLP were found; additional exposure in MW fields (10 mW/cm2), not resulting per se in resorptions or detectable malformations, increased the numbers to 45% (213 of 448) of resorptions and to 70% (167 of 235) fetuses with CL or CLP.+

AI evidence extraction

Main findings

Nonthermal 2,450-MHz microwave exposure (1 or 10 mW/cm2) during pregnancy did not produce resorptions or detectable malformations, but fetal body mass at day 19 was significantly lower than sham controls. Thermogenic exposure (40 mW/cm2) increased resorptions (~25% vs ~2% in controls). Combined exposure to ara-C and microwaves (10 mW/cm2) increased resorptions (45% vs 20% with ara-C alone) and cleft lip/cleft lip and palate (70% vs 30% with ara-C alone).

Outcomes measured

• Resorptions (implantation points)
• Fetal body mass (day-19 fetuses)
• Macroscopically visible malformations (skeletal malformations, cleft palate, cleft lip/cleft lip and palate)
• Teratogenic potency of cytosine arabinoside (ara-C) under combined exposure

Limitations

• Sample size per group not fully reported in the abstract
• Exposure described in power density (mW/cm2) without SAR or dosimetry details
• Malformations assessed as macroscopically visible only (no mention of blinded assessment or histology)
• Animal model; generalizability to humans not addressed in abstract

{
    "study_type": "animal",
    "exposure": {
        "band": "microwave",
        "source": null,
        "frequency_mhz": 2450,
        "sar_wkg": null,
        "duration": "2 h daily on gestation days 1–18"
    },
    "population": "Pregnant Swiss mice and their fetuses",
    "sample_size": null,
    "outcomes": [
        "Resorptions (implantation points)",
        "Fetal body mass (day-19 fetuses)",
        "Macroscopically visible malformations (skeletal malformations, cleft palate, cleft lip/cleft lip and palate)",
        "Teratogenic potency of cytosine arabinoside (ara-C) under combined exposure"
    ],
    "main_findings": "Nonthermal 2,450-MHz microwave exposure (1 or 10 mW/cm2) during pregnancy did not produce resorptions or detectable malformations, but fetal body mass at day 19 was significantly lower than sham controls. Thermogenic exposure (40 mW/cm2) increased resorptions (~25% vs ~2% in controls). Combined exposure to ara-C and microwaves (10 mW/cm2) increased resorptions (45% vs 20% with ara-C alone) and cleft lip/cleft lip and palate (70% vs 30% with ara-C alone).",
    "effect_direction": "harm",
    "limitations": [
        "Sample size per group not fully reported in the abstract",
        "Exposure described in power density (mW/cm2) without SAR or dosimetry details",
        "Malformations assessed as macroscopically visible only (no mention of blinded assessment or histology)",
        "Animal model; generalizability to humans not addressed in abstract"
    ],
    "evidence_strength": "low",
    "confidence": 0.7800000000000000266453525910037569701671600341796875,
    "peer_reviewed_likely": "yes",
    "keywords": [
        "microwave radiation",
        "2450 MHz",
        "pregnancy",
        "gestation",
        "mice",
        "resorptions",
        "fetal weight",
        "cleft palate",
        "cleft lip",
        "teratogenicity",
        "cytosine arabinoside",
        "hyperthermia",
        "nonthermal exposure"
    ],
    "suggested_hubs": []
}

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