Nifedipine is an antagonist to cyclotron resonance enhancement of 45Ca incorporation in human lymphocytes

PAPER manual Cell Calcium 1987 In vitro study Effect: mixed Evidence: Low

Read original paper → DOI: 10.1016/0143-4160(87)90025-x PMID: 3435912 Evidence Lab

Abstract

The incorporation of 45Ca in mixed human lymphocytes was measured following one-hour exposures of the cells to combined steady and periodic magnetic fields designed to probe for cyclotron resonance response in calcium incorporation. Measurements were made as a function of magnetic field frequency, up to 30 Hz, and as a function of magnetic field amplitude, up to 1.5 x 10(-4) Trms. The amplitude measurements demonstrated that the relative 45Ca uptake at resonance follows different mechanisms of interaction above and below 0.2 x 10(-4) Trms. After adjusting the magnetic field configuration for maximum incorporation, we then determined the effects of the calcium influx blocker nifedipine on 45Ca incorporation, with and without simultaneous exposure to this specific magnetic field combination. The presence of nifedipine in both unexposed and exposed cell suspensions resulted in decreased 45Ca uptake, presumably through the slow inward calcium channels. Evidence was found suggesting that nifedipine acts antagonistically to the 45Ca cyclotron resonance tuning signal.

AI evidence extraction

At a glance

Study type

In vitro study

Effect direction

mixed

Population

mixed human lymphocytes (cell suspensions)

Sample size

—

Exposure

ELF other · 1 hour exposures; frequency varied up to 30 Hz; amplitude varied up to 1.5 × 10^(-4) T_rms; combined steady and periodic magnetic fields

Evidence strength

Low

Confidence: 74% · Peer-reviewed: yes

Main findings

One-hour exposure to combined steady and periodic magnetic fields (up to 30 Hz; up to 1.5 × 10^(-4) T_rms) was used to probe cyclotron resonance effects on 45Ca incorporation in mixed human lymphocytes. Relative 45Ca uptake at resonance appeared to follow different interaction mechanisms above vs below 0.2 × 10^(-4) T_rms. Nifedipine decreased 45Ca uptake in both unexposed and exposed suspensions, and evidence suggested nifedipine antagonized the 45Ca cyclotron resonance tuning signal.

Outcomes measured

45Ca incorporation/uptake in human lymphocytes
cyclotron resonance response in calcium incorporation
effect of nifedipine on 45Ca uptake with and without magnetic field exposure

Limitations

Sample size not reported in abstract
In vitro cell-suspension study; generalizability to in vivo outcomes not addressed in abstract
Quantitative effect sizes and statistical details not provided in abstract

Suggested hubs

occupational-exposure (0.15)
Study involves ELF magnetic field exposures, but no specific occupational setting is described.

View raw extracted JSON

{
    "study_type": "in_vitro",
    "exposure": {
        "band": "ELF",
        "source": "other",
        "frequency_mhz": null,
        "sar_wkg": null,
        "duration": "1 hour exposures; frequency varied up to 30 Hz; amplitude varied up to 1.5 × 10^(-4) T_rms; combined steady and periodic magnetic fields"
    },
    "population": "mixed human lymphocytes (cell suspensions)",
    "sample_size": null,
    "outcomes": [
        "45Ca incorporation/uptake in human lymphocytes",
        "cyclotron resonance response in calcium incorporation",
        "effect of nifedipine on 45Ca uptake with and without magnetic field exposure"
    ],
    "main_findings": "One-hour exposure to combined steady and periodic magnetic fields (up to 30 Hz; up to 1.5 × 10^(-4) T_rms) was used to probe cyclotron resonance effects on 45Ca incorporation in mixed human lymphocytes. Relative 45Ca uptake at resonance appeared to follow different interaction mechanisms above vs below 0.2 × 10^(-4) T_rms. Nifedipine decreased 45Ca uptake in both unexposed and exposed suspensions, and evidence suggested nifedipine antagonized the 45Ca cyclotron resonance tuning signal.",
    "effect_direction": "mixed",
    "limitations": [
        "Sample size not reported in abstract",
        "In vitro cell-suspension study; generalizability to in vivo outcomes not addressed in abstract",
        "Quantitative effect sizes and statistical details not provided in abstract"
    ],
    "evidence_strength": "low",
    "confidence": 0.7399999999999999911182158029987476766109466552734375,
    "peer_reviewed_likely": "yes",
    "keywords": [
        "human lymphocytes",
        "45Ca incorporation",
        "calcium uptake",
        "cyclotron resonance",
        "steady magnetic field",
        "periodic magnetic field",
        "ELF magnetic fields",
        "nifedipine",
        "calcium channel blocker"
    ],
    "suggested_hubs": [
        {
            "slug": "occupational-exposure",
            "weight": 0.1499999999999999944488848768742172978818416595458984375,
            "reason": "Study involves ELF magnetic field exposures, but no specific occupational setting is described."
        }
    ]
}

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

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