The Cytome Assay as a Tool to Investigate the Possible Association Between Exposure to Extremely Low Frequency Magnetic Fields and an Increased Risk for Alzheimer's Disease.

Exposure to extremely low frequency magnetic fields (ELF-MF) has been identified as one of the potential environmental risk factors for Alzheimer's disease (AD). However, this is far from being established. So far there is no experimental evidence supporting this alleged association. We have performed an in vitro cytogenetic laboratory investigation to explore the plausibility of such association. Our investigation was based on possible similarities found in cells from AD patients and in cells exposed to ELF-MF. We especially found that 50  Hz ELF-MF increase the frequency of cells with (large) micronuclei and nuclear buds indicating that fields above 50 µT may induce chromosome instabilities as those found in AD patients. It should be stressed yet that results from the few published experimental studies on ELF-MF and AD are rather reassuring. Thus, our findings certainly do not prove anything. They only suggest that further investigations might be necessary.

Co-exposure of ELF-magnetic fields and chemical mutagens: An investigation of genotoxicity with the SOS-based VITOTOX test in Salmonella typhimurium.

It is believed that extreme low frequency magnetic fields (ELF-MF) are not mutagenic, at least at exposure levels below 100 µT. Synergistic or co-operative effects with environmental mutagens remain possible yet. We therefore investigated the effects of ELF-MF in conjunction with 4 different well known chemical mutagens having different modes of action. For this purpose the bacterial Vitotox test was used. Our study confirmed previous results which showed that a 100 µT magnetic field (50 Hz) does not damage DNA and hence is not mutagenic in this assay and that there was also no influence on the DNA damaging capacity of the used mutagens.

Genotoxicity testing of 3,4,5-trimethylfuran-2(5H)-one, a compound from plant-derived smoke with germination inhibitory activity.

Plant-derived smoke and certain smoke compounds improve seed germination and enhance seedling growth of many species. Thus, smoke-infused water and the active smoke-derived compounds have the potential to be used in different agricultural and horticultural applications. However, despite these interesting and potentially practical properties, it should also be ascertained whether such compounds may pose a health risk, particularly if they are to be used in the production of food or fodder crops. Amongst some of the aspects that would be important to understand are any possible genotoxic properties that the compounds may possess due to potential carry-over effects. Here, we report on a genotoxicity study of 3,4,5-trimethylfuran-2(5H)-one, a compound from plant-derived smoke previously shown to have germination inhibitory activity. Using two in vitro tests, namely the bacterial VITOTOX® test (with/without S9 metabolic activation) and the cytome assay on human C3A cells, no genotoxicity or toxicity was found. Furthermore, these results support a previous study where a related smoke-derived compound with germination promoting properties was investigated.

Can cytogenetics explain the possible association between exposure to extreme low-frequency magnetic fields and Alzheimer's disease?

Recently, a number of epidemiological studies have suggested that occupational as well as residential exposure to extreme low-frequency electromagnetic fields (ELF-EMFs) may be a risk factor for Alzheimer's disease. This is not proven yet and there are no known biological mechanisms to explain this alleged association. Alzheimer's disease is characterized by a number of events that have, at least partially, a genetic origin. In particular, trisomy of chromosomes 17 and 21 seems to be involved. Overall ELF-EMFs have not been identified as genotoxic agents, but there are some papers in the scientific literature that indicate that they may enhance the effects of agents that are known to induce mutations or tumors. There are also some indications that ELF-EMFs may induce aneuploïdy. This opens some perspectives for investigating the alleged association between ELF-EMFs and Alzheimer's. This paper reviews the possibility of a cytogenetic association between the electromagnetic fields and Alzheimer's disease.

Genotoxicity investigation of ELF-magnetic fields in Salmonella typhimurium with the sensitive SOS-based VITOTOX test.

We performed a genotoxicity investigation of extremely low-frequency (ELF) magnetic fields (MFs, 50 Hz, 100 and 500 µT, 1 and 2 h exposure) alone and in combination with known chemical mutagens using the VITOTOX test. This test is a very sensitive reporter assay of Salmonella typhimurium bacteria based on the SOS response. Our study showed that ELF-MFs do not induce SOS-based mutagenicity in S. typhimurium bacteria and do not show any synergetic effect when combined with chemical mutagens.

In vitro investigations related to the hypothesis that Lipoatrophia semicircularis finds its origin in electro-stimulation.

Lipoatrophia semicircularis (L.s.) is an idiopathic condition characterized by semicircular impressions of the skin, usually at the front and sides of both thighs. It is characterized by atrophy of the subcutaneous adipocytes whereas the skin and muscles remain normal. L.s. was originally considered to be very rare but over the past 13 years an outburst of L.s. has been observed in companies in Belgium and later on also in companies in other countries (e.g., Spain) where several hundred individuals were diagnosed with L.s. All these subjects belonged to the administrative personnel and worked in renovated or new offices. Different hypotheses have been put forward to explain the appearance of Lipoatrophia semicircularis but the hypothesis of an 'electric' origin of L.s. is probably the best documented and plausible. The present study was aimed to further investigate the likelihood of this hypothesis. The alkaline comet assay was used to investigate DNA damage in cells of different origin following exposure to a (strong) electric current. It was found that adipocytes showed more DNA damage than the other cells and hence that they are more vulnerable to such a current than macrophages and white blood cells. It was also found that DNA damage is significantly induced by an electric current in the blood from L.s. subjects whereas this is not so in blood from subjects without L.s. This may indicate that L.s. subjects are more responsive to an induced electric current and supports the hypothesis of an 'electric' origin of L.s.

Cytogenetic investigation of subjects professionally exposed to radiofrequency radiation.

Nowadays, virtually everybody is exposed to radiofrequency radiation (RFR) from mobile phone base station antennas or other sources. At least according to some scientists, this exposure can have detrimental health effects. We investigated cytogenetic effects in peripheral blood lymphocytes from subjects who were professionally exposed to mobile phone electromagnetic fields in an attempt to demonstrate possible RFR-induced genetic effects. These subjects can be considered well suited for this purpose as their RFR exposure is 'normal' though rather high, and definitely higher than that of the 'general population'. The alkaline comet assay, sister chromatid exchange (SCE) and chromosome aberration tests revealed no evidence of RFR-induced genetic effects. Blood cells were also exposed to the well known chemical mutagen mitomycin C in order to investigate possible combined effects of RFR and the chemical. No cooperative action was found between the electromagnetic field exposure and the mutagen using either the comet assay or SCE test.

Screening of medicinal plants used in South African traditional medicine for genotoxic effects.

Dichloromethane and 90% methanol extracts from 51 South African medicinal plants were evaluated for potential genotoxic effects using the bacterial Ames and VITOTOX tests with and without metabolic activation. Dichloromethane extracts from bulbs of Crinum macowanii showed mutagenicity in strain TA98 with and without metabolic activation, whereas extracts from leaves of Chaetacme aristata and foliage of Plumbago auriculata showed mutagenicity and/or toxicity. Extracts from the leaves of Catharanthus roseus and twigs of Combretum mkhzense were mutagenic with metabolic activation only. The only 90% methanol extracts that were mutagenic in strain TA98 were from the leaves of C. roseus and Ziziphus mucronata in the presence of metabolic activation. No genotoxic effects were found in strain TA100 or in the VITOTOX test.