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  • Author: Ivan Pavičić x
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Disturbance of Cell Proliferation in Response to Mobile Phone Frequency Radiation

The aim of study was to determine the influence of mobile phone frequency radiation on the proliferation, cytoskeleton structure, and mitotic index of V79 cells after 1 h, 2 h, and 3 h of exposure. V79 cells were cultured in standard laboratory conditions and exposed to continuous-wave (CW) RF/MW radiation of 935 MHz, electric field strength of (8.2±0.3) V m-1, and specific absorption rate (SAR) of 0.12 W kg-1. To identify proliferation kinetics, the cells were counted for each hour of exposure 24 h, 48 h, 72 h, and 96 h after respective exposures. Microtubule proteins were determined using specific immunocytochemical methods. Cell smears were analysed under a fluorescent microscope. The study included negative and positive controls. Mitotic index was determined by estimating the number of dividing cells 24 h after exposure and dividing it with the total number of cells. In comparison to the controls, cell proliferation declined in cells exposed for three hours 72 h after irradiation (p<0.05). Microtubule structure was clearly altered immediately after three hours of irradiation (p<0.05). The mitotic index in RF/MW-exposed cells did not differ from negative controls. However, even if exposure did not affect the number of dividing cells, it may have slowed down cell division kinetics as a consequence of microtubule impairment immediately after exposure.

Djelovanje Radiofrekvencijskog Elektromagnetskog Zračenja na Spermatogenez u Sisavaca

Prema podacima dostupnima javnosti, smatra se da je u Hrvatskoj broj aktivnih mobilnih linija dosegao broj od oko 4 milijuna, dok se u cijelome svijetu taj broj penje na vrtoglave 2 milijarde. Zbog toga se postavlja pitanje djelovanja radiofrekvencijskog (RF) zračenja na zdravlje čovjeka, posebno na reprodukcijsko zdravlje i eventualne posljedice na zdravlje budućeg potomstva. Svrha ovog članka je pregled dosadašnjih istraživanja utjecaja RF zračenja mobilnih telefona na muški reprodukcijski sustav. Neka istraživanja provedena u uvjetima in vivo i in vitro pokazala su da RF zračenje može utjecati na stanicu i pojedine stanične dijelove. Dio istraživanja je pokazao da RF zračenje može utjecati na reprodukcijski sustav sisavaca i na stanice spermatogeneze. Budući da je spermatogeneza u normalnim fiziološkim uvjetima uravnotežen proces diobe, sazrijevanja i pohrane stanica, podložan je i osjetljiv na vanjske podražaje. Posebno osjetljive strukture u stanici su proteini koji čine stanični kostur, odnosno citoskelet. Citoskelet je strukturalni i funkcionalni dio stanice koji, između ostaloga, ima važnu ulogu u pokretanju spermija te sudjeluje u morfološkim i funkcionalnim promjenama stanica tijekom spermatogeneze.

Over the years, due to rapid technological progress, radiation from man-made sources exceeded that of natural origin. There is a general concern regarding a growing number of appliances that use radiofrequency/ microwave (RF/MW) radiation with particular emphasis on mobile communication systems. Since nonthermal biological effects and mechanisms of RF/MW radiation are still uncertain, laboratory studies on animal models, tissues, cells, and cell free system are of extraordinary importance in bioelectromagnetic research. We believe that such investigations play a supporting role in public risk assessment. Cellular systems with the potential for a clear response to RF/MW exposures should be used in those studies. It is known that organism is a complex electrochemical system where processes of oxidation and reduction regularly occur. One of the plausible mechanisms is connected with generation of reactive oxygen species (ROS). Depending on concentration, ROS can have both benefi cial and deleterious effects. Positive effects are connected with cell signalling, defence against infectious agents, and proliferative cell ability. On the other hand, excessive production, which overloads antioxidant defence mechanism, leads to cellular damage with serious potential for disease development. ROS concentration increase within the cell caused by RF/MW radiation seems to be a biologically relevant hypothesis to give clear insight into the RF/MW action at non-thermal level of radiation. In order to better understand the exact mechanism of action and its consequences, further research is needed in the fi eld. We would like to present current knowledge on possible biological mechanisms of RF/MW actions.

Non-Thermal Biomarkers of Exposure to Radiofrequency/Microwave Radiation

This article gives a review or several hypotheses on the biological effects of non-thermal radiofrequency/microwave (RF/MW) radiation and discusses our own findings from animal and in vitro studies performed over the last decade. We have found that RF/MW radiation disturbs cell proliferation and leads to cell differentiation in the bone marrow, which is reflected in the peripheral blood of rats. Repeated RF/MW radiation can also temporarily disrupt melatonin turnover. The observed changes seem to be a sign of adaptation to stress caused by irradiation rather than of malfunction. The article looks further into the basic mechanisms of RF/MW biological action, including cell growth parameters, colony-forming ability, viability, and the polar and apolar protein cytoskeleton structures. The observed reversible cell changes significantly obstructed cell growth. In contrast to the apolar intermediate proteins, the intracellular polar microtubule and actin fibres were damaged by radiation in a time-dependent manner. These significantly altered parameters can be considered as the biomarkers of exposure. Future research should combine dosimetry, experimental studies, and epidemiological data.

Abstract

Pesticides are a highly diverse group of compounds and the most important chemical stressors in the environment. Mechanisms that could explain pesticide toxicity are constantly being studied and their interactions at the cellular level are often observed in well-controlled in vitro studies. Several pesticide groups have been found to impair the redox balance in the cell, but the mechanisms leading to oxidative stress for certain pesticides are only partly understood. As our scientific project “Organic pollutants in environment – markers and biomarkers of toxicity (OPENTOX)” is dedicated to studying toxic effects of selected insecticides and herbicides, this review is focused on reporting the knowledge regarding oxidative stress-related phenomena at the cellular level. We wanted to single out the most important facts relevant to the evaluation of our own findings from studies conducted on in vitro cell models.

Abstract

The unfavourable outcomes of mobile phone use on male fertility have still not been fully elaborated. To establish the potentially adverse effects of everyday exposure to radiofrequency radiation (RF) on humans, we performed a controlled animal study that aimed to investigate the influence of RF radiation on rat testis histology as well as the amount, mobility, and structure of epididymal free sperm cell population. Eighteen adult male rats were divided into two groups of nine. One group comprised sham-exposed control animals, while the other group endured total body irradiation for an hour daily during two weeks. A 915 MHz RF field, power density of 2.4 W m-2 and strength of 30 V m-1 was generated in a Gigahertz Transversal Electromagnetic chamber. The specific absorption rate (SAR) was 0.6 W kg-1. Body mass and temperature were measured before and after each exposure treatment. Immediately after the last exposure, the animals were sacrificed and testes removed and prepared for histological analysis. The free sperm cells were collected from the cauda epididymis and their quantity, quality, and morphology were microscopically determined using a haemocytometer. No statistically significant alteration in any of the endpoints was observed. This study found no evidence of an unfavourable effect of the applied RF radiation on testicular function or structure. Based on these results, we can conclude that short-time intermittent exposure to RF radiation does not represent a significant risk factor for rat reproductive functions.

Abstract

Many personal care products on the market contain endocrine disrupting chemicals, including parabens. Parabens are well known chemical additives used as preservatives. They have been found in mammary glands and breast cancer tissues. At the same time, the general public is increasingly exposed to plastic micro- and nanoparticles generated during plastic production and waste disposal. Exposure to chemical cocktails is a realistic scenario of high public health interest, in which many types of compounds such as these two may exhibit synergistic or additive adverse effects. This study evaluated the effects of plastic nanoparticles, parabens, and their mixture on the viability and proliferation of two human breast cancer cell lines: MDA-MB 231, which lacks oestrogen receptors, and MCF-7, which expresses these receptors. Parabens increased proliferation of oestrogen-sensitive breast cancer cells, and this effect became synergistic in the presence of plastic nanoparticles. The mechanism behind synergy may be related to the translocation and adsorption properties of nanoplastics, which served as a Trojan horse to expose cells to parabens more efficiently. These preliminary findings support growing evidence warning about the urgent problem of human exposure to combinations of plastic waste and contingent chemicals.

Abstract

Garlic is a valuable source material for medicines due to its known antitumor, hypolipidaemic, antioxidant, and immunomodulatory effects. This study compares the protective effects of conventionally grown (CG) and in vitro propagated garlic (PG) against hydrogen peroxide-induced cytotoxicity in HepG2 cells and their antioxidant activity. Garlic used in this study was obtained by planting garlic cloves or by planting the transplants of PG directly in the field. At the end of the vegetation period, CG and PG were sampled and extracts prepared for the experiment. Compared to conventionally grown garlic bulbs, PG leafy part yielded significantly higher content of polyphenols, flavonoids and alliin, and also showed equal or higher antioxidant activity, measured by the cell viability test, GSH and ROS level. Moreover, PG can be produced in less time (shorter vegetation period) and with significantly less material (cloves). Significantly higher content of alliin, polyphenols, and flavonoids and significantly higher yield of plant biomass in PG has a great potential to become a new production model with improved garlic properties as a medicine material.

Abstract

In this 28 day-study, we evaluated the effects of herbicide glyphosate administered by gavage to Wistar rats at daily doses equivalent to 0.1 of the acceptable operator exposure level (AOEL), 0.5 of the consumer acceptable daily intake (ADI), 1.75 (corresponding to the chronic population-adjusted dose, cPAD), and 10 mg kg−1 body weight (bw) (corresponding to 100 times the AOEL). At the end of each treatment, the body and liver weights were measured and compared with their baseline values. DNA damage in leukocytes and liver tissue was estimated with the alkaline comet assay. Oxidative stress was evaluated using a battery of endpoints to establish lipid peroxidation via thiobarbituric reactive substances (TBARS) level, level of reactive oxygen species (ROS), glutathione (GSH) level, and the activity of glutathione peroxidase (GSH-Px). Total cholinesterase activity and the activities of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) were also measured. The exposed animals gained less weight than control. Treatment resulted in significantly higher primary DNA damage in the liver cells and leukocytes. Glyphosate exposure significantly lowered TBARS in the liver of the AOEL, ADI, and cPAD groups, and in plasma in the AOEL and cPAD group. AChE was inhibited with all treatments, but the AOEL and ADI groups significantly differed from control. Total ChE and plasma/liver ROS/GSH levels did not significantly differ from control, except for the 35 % decrease in ChE in the AOEL and ADI groups and a significant drop in liver GSH in the cPAD and 100xAOEL groups. AOEL and ADI blood GSH-Px activity dropped significantly, but in the liver it significantly increased in the ADI, cPAD, and 100xAOEL groups vs. control. All these findings show that even exposure to low glyphosate levels can have serious adverse effects and points to a need to change the approach to risk assessment of low-level chronic/sub-chronic glyphosate exposure, where oxidative stress is not necessarily related to the genetic damage and AChE inhibition.