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Immunologic and Cancer-Related Aspects of Exposure to Low-Level Microwave and Radiofrequency Fields
Published in Andrew A. Marino, Modern Bioelectricity, 2020
Stanislaw Szmigielski, Marian Bielec, Slawomir Lipski, Grazyna Sokolska
As mentioned before, Byus et al. (10) found strong inhibition of histone protein kinase in cultured human lymphocytes exposed to 450-MHz MWs, sinusoidally modulated at 16 Hz, with a dependence of the effect on the roodulation frequency, Recently, the same authors (11) extended their studies in ways that appear directly to relate to cancer promotion. They investigated the effect of cancer-promoting phorbol esters (TPA) on the activity of ornithine decarboxylase (an enzyme present in all nucleated cells, being essential for synthesis of poly amines, which in turn, are required for DNA synthesis and cell growth) in cultured hepatoma cells invitro (Reuber H 35 line). Activity of the above decarboxylase was increased 1, 5-fold during exposure (1 mW/cm2), and the elevated activity persisted for several hours after a 1-hour exposure, Also, the increased activity evoked in the cultured cells by TPA was potentiated by prior exposure to the roodulated MWs, The authors concluded that the cell membranes were the site of transductive coupling of MW/RF fields modulated at low frequencies, because the tumor promoter TPA has a specific cell membrane protein kinase receptor (the calcium-phospholipid kinase or protein kinase C), and the synergy between TPA and the modulated MW fields was consistent with this common site of action (11).
Health effects of exposure to extremely low frequency fields
Published in Riadh Habash, BioElectroMagnetics, 2020
Ornithine Decarboxylase (ODC) is an enzyme that plays an important role in regulating cell growth through synthesis of polyamines necessary for protein and DNA synthesis. It is an enzyme activated during carcinogenesis. Studies were carried out to investigate whether there were effects on ODC due to EM field exposure. An in vitro study [122,123] found increased ODC activity in three cell lines in response to a sinusoidal 60 Hz electric field (10 mV/cm) for only 10 s duration. Stimulation in the activity of ODC in cultured cells by RFR with ELF modulation was also reported [124,125]. The results depended upon the type of modulation employed. These effects were noted only for certain modulations of the carrier wave, portraying the window effect (an effect that appears at a certain frequency, but not at higher or lower frequencies). In addition, changes in ODC have also been reported from ELF exposure in vivo [126]. It is clear from the literature that a variety of in vitro studies have demonstrated that ELF exposure affects ODC activity and cellular proliferation, while exposure to fields below 0.1 mT have not been convincingly associated with adverse health effects.
Chemical Carcinogenesis in Skin: Causation, Mechanism, and Role of Oncogenes
Published in Rhoda G. M. Wang, James B. Knaak, Howard I. Maibach, Health Risk Assessment, 2017
All skin tumor promoters are strong irritant mitogens, and produce sustained epidermal hyperplasia which has been proposed as a prerequisite for promotion.28 Several histopathological alterations such as induction of dark basal keratinocytes and dismal infiltration of polymorphonuclear leukocytes, in addition to inflammation and hyperplasia, are believed to be the important events in the process of skin tumor promotion. The most important biochemical response to the brief exposure to TPA is the dramatic induction of epidermal ornithine decarboxylase activity which catalyzes the first step in the biosynthesis of polyamines.7 Intracellular polyamine levels are regulated in response to cell proliferation, differentiation, and transformation. Inducibility of ornithine decarboxylase and mitogenic activity are considered as important characteristics of tumor promotion. Other biochemical responses to tumor promoters include increased synthesis of DNA, RNA, protein, phospholipids, prostaglandins, increased phosphorylation of histone, increased activity of protein kinase C (PKC), histidine decarboxylase and protease, and decrease in the activities of superoxide dismutase and catalase.6,8 The importance of several of these individual effects is discussed elsewhere in this chapter.
Recognition of the prioritized types and individual of pharmaceuticals and personal care products (PPCPs) in the drinking water of Shanghai and a health risk assessment
Published in Human and Ecological Risk Assessment: An International Journal, 2019
Guoqiang Gu, Haowen Yin, Qing Zhu, Lu Shen, Kun Zhang, Min Liu, Qiang Wu
Among the 6 types of PPCPs investigated, hormones, blockers, and veterinary drugs were found to have low concentrations in drinking water and low exposure risks. Greater attention was paid to the risks posed by psycholeptics, dicyclohexylamine, and cyclophosphamide. Dicyclohexylamine is a prominent pollutant with a high detection frequency and concentration in drinking water; however, surprisingly little attention is paid to its effect on human health. Mitchell et al. found that dicyclohexylamine has potent inhibitory activity against the homozygous typing cell and ornithine decarboxylase (Mitchell et al. 1985). ADI could not be deduced being short of animal health effect data, and the corresponding risk to human health could not be quantified. Caution should be taken in the future assessment of its risk to human health. Only cyclophosphamide, and sertraline and sulpiride were quantified to determine the associated human health risk. For sulpiride, ADI couldn't be found, and defined daily dose (DDD) is instead. The results of the human health risk assessment are shown in Table 2. For these three PPCPs, even at the maximum exposure concentration, an associated human risk is impossible due to their corresponding risk quotient of far below “1”. The risk of sulpiride is negligible with value of 2.18 × 10–5, which are two orders of magnitudes lower than that of sertraline. Therefore, sertraline is priority pollutant for the kind of psycholeptics. However, among the three PPCPs, cyclophosphamide posed the highest risk potential, exceeding the sum impact of sertraline and sulpiride, although the exposure level for the compound is lower for sertraline and sulpiride. For psycholeptics, only two typical drugs were included. For antitumor drugs, one representative drug was investigated and evaluated. Therefore, the risk of these agents is likely underestimated. As a result, caution should be used in assessing the human health risk posed by these two types of drugs because many other similar types of drugs are also widely used in Shanghai.