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PubMed2006

Effect of electromagnetic fields on the denitrification activity of Paracoccus denitrificans.

Enzymatic activity (denitrification) of Paracoccus denitrificans was estimated electrochemically by reduction of duroquinone (DQ). Graphite electrodes covered with whole bacterial cells behind a dialysis membrane were used for measurement. P. denitrificans reduce nitrate and/or nitrite under anaerobic conditions to nitrogen gas. DQ acts as an electron mediator. After donation of the electrons to the respiratory system of the bacteria, produced DQ is reduced to durohydroquinone on the electrode surface electrocatalytically. P. denitrificans were exposed to low-frequency magnetic field (10 mT, 50 Hz) for 24 min. In comparison with the control samples, the reduction peak of I-E curves that represent denitrification activity of the cells decreased significantly after magnetic field exposure. The decrease of the peak current was about 20%. The CFU-colony forming units-method was used to estimate the number of surviving bacteria. After 24 min exposure of 10 mT magnetic field P. denitrificans culture on electrode indicates 21% bacterial death.

Colony-Forming Units Assay↗
PubMed1998

Effects of electromagnetic fields on the levels of biogenic amine metabolites, quinolinic acid, and beta-endorphin in the cerebrospinal fluid of dairy cows.

Eight multiparous non-lactating pregnant Holstein cows at 198 +/- 35 d of gestation, weighing 608 +/- 24 kg, were confined to wooden metabolic cages in an electric and magnetic field chamber with a 12:12 h light:dark cycle. Subarachnoidal catheters were installed 5 d before the activation of the electric and magnetic fields. The cows were exposed to electric and magnetic fields (60 Hz, 10 kV/m and 30 microT) continuously except for the feeding and cleaning time for an average of 21.44 +/- 1.4 h per day for a period of 30 d. Cerebrospinal fluid samples were collected on three consecutive days before an exposure period of 30 d, on the last 3 d of the exposure period, and for 3 d starting 5 d after the exposure period. The concentrations of beta-endorphin, tryptophan, 5-hydroxyindoleacetic acid, homovanillic acid, 3-methoxy-4-hydroxyphenylethyleneglycol and quinolinic acid in cerebrospinal fluid were determined. There was a significant increase in quinolinic acid, and a trend towards an increase in tryptophan, findings consistent with a weakening of the blood-brain barrier due to exposure to the electric and magnetic fields.

Animals↗
PubMed1999

Childhood brain tumors and residential electromagnetic fields (EMF).

There are many recent comprehensive reviews of the residential EMF epidemiologic literature, but they do not attempt to cover the issue of childhood brain tumors and EMF in depth. We present here background information on descriptive epidemiology of known or suspected causes of childhood brain tumors and a detailed review of studies that have examined the associations between EMF as represented by various surrogates, and childhood brain tumors. We evaluated nine studies of childhood brain tumors and residential exposure to EMF based on wire codes, distance, measurements, and modeling, and six studies that examined the use of appliances by children or their mothers during pregnancy. For each study we discussed analytical and methodological issues including choice of cutpoints, nonconcurrent control selection, random digit dialing, differential participation, and ability of a study to detect an association. On the basis of this comprehensive review of all available childhood brain cancer studies, we do not see support for an overall association between EMF and childhood brain cancer. This lack of support applied for all surrogates of past magnetic fields, including wire code, distance, measured or calculated fields, and use of appliances by either child or mother.

Brain Neoplasms↗
PubMedDate not supplied

Electromagnetic fields and infant incubators.

Two models of infant incubators were studied to determine the strength of the magnetic field generated by the heater and fan motors. Measurements were taken at intervals along the center line of the incubator. The results show that fields greater than 100 milligauss and 25 milligauss were measured in the C-86 and C-100 model Isolettes, respectively.

Electromagnetic Fields↗
PubMed1997

Exposure to a 50 Hz electromagnetic field induces activation of the Epstein-Barr virus genome in latently infected human lymphoid cells.

The EBV genome in latently infected lymphoid cells offers an opportunity to follow effects on the transcriptional and translational product clearly distinguishable from those of the host cell genome. Exposure of Akata cells, a human lymphoid cell line latently infected by the EBV genome, to a 50 Hz EMF resulted in an increased number of cells expressing the virus early antigens. This finding provides additional evidence that DNA can be modulated by a magnetic field.

Antigens, Viral↗
PubMed2002

Biological responses of tight junction to ionizing radiation and electromagnetic field expostion.

The tight junctions form and regulate the paracellular barrier in the intercellular spaces between epithelial and endothelial cells. They play important roles in the cellular and pathological processes, which follow exposure to radiation. Therefore, analysis of their changes upon different kind of irradiation may help to understand the basic events governing their function and give important information for the radiobiological research and clinical practice as well. The immunohistochemical data on the distribution of occludin presented here demonstrate the breakdown of tight junctions in Madin Darby kidney cells exposed to ionizing irradiation and show, on the other hand that magnetic field exposures upon 100 microT leave the occludin staining pattern intact.

Animals↗
PubMed1997

Lymphomas in E mu-Pim1 transgenic mice exposed to pulsed 900 MHZ electromagnetic fields.

Whether radiofrequency (RF) fields are carcinogenic is controversial; epidemiological data have been inconclusive and animal tests limited. The aim of the present study was to determine whether long-term exposure to pulse-modulated RF fields similar to those used in digital mobile telecommunications would increase the incidence of lymphoma in E mu-Pim1 transgenic mice, which are moderately predisposed to develop lymphoma spontaneously. One hundred female E mu-Pim1 mice were sham-exposed and 101 were exposed for two 30-min periods per day for up to 18 months to plane-wave fields of 900 MHz with a pulse repetition frequency of 217 Hz and a pulse width of 0.6 ms. Incident power densities were 2.6-13 W/m2 and specific absorption rates were 0.008-4.2 W/kg, averaging 0.13-1.4 W/kg. Lymphoma risk was found to be significantly higher in the exposed mice than in the controls (OR = 2.4. P = 0.006, 95% CI = 1.3-4.5). Follicular lymphomas were the major contributor to the increased tumor incidence. Thus long-term intermittent exposure to RF fields can enhance the probability that mice carrying a lymphomagenic oncogene will develop lymphomas. We suggest that such genetically cancer-prone mice provide an experimental system for more detailed assessment of dose-response relationships for risk of cancer after RF-field exposure.

Animals↗
PubMed2004

Examining the effects of electromagnetic fields emitted by GSM mobile phones on human event-related potentials and performance during an auditory task.

OBJECTIVE: Due to the widespread use of mobile phones (MP), it is important to determine whether they affect human physiology. The aim of this study was to explore the sensitivity of auditory event-related potentials to electromagnetic emissions. METHODS: Twelve participants attended two sessions, 1 week apart. Participants performed an auditory oddball task while they were exposed to an active MP during one session and sham exposure during the other. Each condition lasted 1 h and order was counterbalanced. N100 and P200 latencies and amplitudes were analysed for non-target waveforms, and N200 and P300 latencies and amplitudes were analysed for target waveforms. RESULTS: In real relative to sham exposure N100 amplitude and latency to non-targets were reduced, with the reduction larger over midline and right hemisphere sites. P300 latency to targets was delayed in the real exposure condition, however as this difference was greatest at left frontal and left central sites the interpretation of this result is unclear. Reaction time increased in the real relative to sham condition. No difference in accuracy was found. CONCLUSIONS: The results suggest that MP exposure may affect neural activity, particularly in proximity to the phone, however caution should be applied due to the small sample size.

Acoustic Stimulation↗