Documents genotoxic effects 23 results

"The aim of this study was to investigate the possibility of subtoxic exposure to pesticides causing chromosome aberrations in greenhouse workers.In a cross-sectional and prospective study design chromosome aberration frequencies in cultured lymphocytes were examined for 116 greenhouse workers exposed to a complex mixture of almost 50 insecticides, fungicides, and growth regulators and also for 29 nonsmoking, nonpesticide-exposed referents.The preseason frequencies of chromosome aberrations were slightly but not statistically significantly elevated for the greenhouse workers when they were compared with the referents. After a summer season of pesticide spraying in the greenhouses, the total frequencies of cells with chromosome aberrations were significantly higher than in the preseason samples (P=0.02) and also higher than for the referents (P=0.05). This finding was especially due to an increased number of cells with chromatid gaps between the first and second samples (P=0.001). The results may reflect an additive genotoxic effect of the spraying season, for which the use of insecticides and growth regulators (but not fungicides) culminates. The highest elevation in the risk of chromatid gaps was observed for persons who did not use gloves during re-entry activities such as nipping, cutting, pricking, and potting (risk ratio 2.88, 95% confidence interval 1.63-5.11). The present results suggest a genotoxic effect from a complex subtoxic occupational pesticide exposure. In general, the findings indicate the importance of personal protection, during high-exposure re-entry activities, in preventing pesticide uptake and genetic damage. ... "

"Nanoparticles are considered as powerful tools in nanotechnological applications. Due to their unique physicochemical properties, their interactions with different biological systems have been shown. Nanomaterials have been successfully used as coating materials or treatment and diagnosis tools. Nevertheless, toxic effects of nanoparticles in vitro and in vivo have also been reported. Here, we summarize the current state of knowledge on exposure routes, cellular uptake and toxicological activities of the commonly used nanoparticles. In this context, we discuss the mechanisms of toxicity of nanoparticles involving perturbation of redox milieu homeostasis and cellular signaling pathways."

"The development, production and technological applications of carbon nanotube are rapidly growing, due to the unique characteristics of these fibers. Consequently, an increase is also expected in human exposure to such materials. However, little is still known about the safety of the multiple sorts of carbon nanotubes.
Recent studies have suggested that some types of multiwalled carbon nanotubes (MWCNTs) have similar effects as asbestos. This report shows that rigid, long and needle-like MWCNTs induce inflammation and DNA damage in the lungs and in cultured cells, while flexible, long and tangled MWCNTs do not. It appears that the rigidity of MWCNTs is a key feature in triggering a specific inflammatory reaction and in causing cellular alterations involved in cancer formation.
These results provide new information on the adverse effects of MWCNTs and are useful in assessing which forms of MWCNTs require regulatory attention and special safety measures in occupational settings."

"Abstract The aim of this study was to identify the health hazards and possible exposure surveillance markers of workers exposed to nanoparticles during manufacturing and application in comparison to a group of unexposed workers. For this longitudinal study, we recruited 158 nanomaterial-handling workers and 104 non-exposed workers from 14 manufacturing plants in Taiwan (baseline). Among them, 124 nanomaterial-handling workers and 77 unexposed workers were monitored 6 months later. We investigated pulmonary and cardiovascular disease markers, inflammation and oxidative stress markers, antioxidant enzymes and genotoxicity markers. Antioxidant enzymes (superoxide dismutase, glutathione peroxidase) and cardiovascular markers (vascular cell adhesion molecule, paraoxonase) were significantly associated with nanomaterial-handling during the 6-month follow-up period. In addition, the small airway damage marker (Clara cell protein 16) and lung function test parameters were also significantly associated with handling nanomaterials. The study markers and lung function tests are possible markers that could be useful for surveillance of nanomaterial-handling workers."

"NMs (nanomaterials), defined as materials with at least one dimension smaller than 100 nm, are able to induce genotoxic effects. One of the hypotheses of the mode-of-action in which they exert their genotoxic potential is to mechanically interfere with subcellular structures, in particular the microtubules. In the present paper, we review studies exploring interactions between NMs and tubulin; therefore a PubMed literature search was performed. From this search 12 studies, applying both acellular and cellular assays, were retrieved and are summarized according to endpoint and particle type. These studies show that there are interactions between different types of NMs and tubulins in both acellular and cellular systems. For several types of NMs, the multi-walled carbon nanotubes, amorphous SiO(2), TiO(2) and CoCr, an induction of aneuploidy was observed in vitro. There is, therefore, a critical need to assess the capacity of NMs to interfere with the cytoskeleton, and in particular the tubulins. This might require definition of relevant dosimetry, adaptations of some testing protocols, possibly development of new methodologies and studies on a larger size-range of NMs."

"Adverse Effects of Engineered Nanoparticles: A Disease-Oriented Approach provides a systematic evaluation of representative engineered nanomaterial (ENM) of high volume production and of high economic importance. Each class of nanomaterials discussed includes information on what scientists, industry, regulatory agencies and the general public need to know about nanosafety. This book, written by leading international experts in nanotoxicology and nanmoedicine, gives a comprehensive view of the health impact of ENM, focusing on their potential adverse effects in exposed workers, consumers and patients. The beneficial applications, both diagnostic and therapeutic, of ENM are also highlighted. This book fills an important need in terms of bridging the gap between experimental findings and human exposure to ENM, and the clinical and pathological consequences of such exposure in the human population."

"The results of the dialogue pertain on the one hand to procedural issues, and on the other hand to the results of these procedures, i.e. the evaluations.

First, the procedures that MUT developed and enhanced for the risk evaluation. This includes the initiation of a risk dialogue as well as instruments for the characterization of the evaluations of individual research studies.

The most important innovation is the aptly named "evidence framework", that allows for a transparent summarization of the experts' line of reasoning. As always, the summarization of individual studies into an overall evaluation is dependent upon their interpretation. Consequently, it is not surprising that subjective assessment measures are apparent since there exist no unambiguous rules or evaluation-standards as to the approach and implementation of how very different studies with at times contradictory findings are to be summarized into an overall picture.

To address this shortcoming of the risk evaluation process, MUT has developed the "evidence framework" with which the most crucial arguments for as well as against a risk suspicion, the conclusions of the experts, and the remaining uncertainties can be better understood.

For several issues, clarifications of content could be achieved through the dialogue process. In other areas, contradictions and ambiguity remain, which signifies a demand for future research. Consequently, according to the assessment of the experts, the present research studies provide no indication that high-frequency electromagnetic fields of mobile phone communication cause cancer in animal experiments or promote cancer growth. The studies of the blood-brain-barrier also find no indications of effects from electromagnetic fields by mobile phone communication.

Furthermore, the experts concluded that the experimentally determined effects of mobile phone communication on the central nervous system do not pose a recognizable health disadvantage. The same applies to the indications of genetic damage. Since this does not result in damage to the cells, it does not support the derivation of a health endangerment, according to the opinion of the experts.

For most impairments of well-being - the exception being headaches - the experts view the weight-of-evidence as so weak, that an evaluation is hardly feasible. However, from the perspective of the experts, the few existing research findings don't indicate a link to exposure with HF EMF. Admittedly, the experts see an indication of a link between headaches and mobile phone usage. However, it remains uncertain whether this proves a relationship between electromagnetic fields and headache, or whether the cause could simply be telephone stress.

The issue of a special sensitivity (electromagnetic hypersensitivity) of certain persons to the EMF of mobile phone communication could not be conclusively clarified. Admittedly, no findings that speak in favor of the existence of such a special sensitivity could be found, but it can also not be ruled out with certainty. For the same reason, it cannot be evaluated whether effects may possibly manifest themselves in sick or health-impaired individuals.

The findings regarding epidemiological cancer studies are in part contradictory. Consequently, the experts arrived at different evaluations: on the one hand they evaluated that a cancer-promoting effect is likely not to be expected, but on the other hand they evaluated that there is a vague initial suspicion. The scientists agreed, however, that after a few years of use of mobile phones, an increased risk of tumors is not to be expected.

Altogether, in light of the six topic areas investigated, support for the hypothesis that EMF of mobile phone communication exhibits unhealthy effects was not strengthened."

(Extract from the website)

"Premature chromosome condensation (PCC) has importance among others in Down's syndrome and ataxia teleangiectasia, and in human neoplastic diseases. PCC can be induced by environmental chemical and physical genotoxic agents, as well as it can be used in the investigation of chromosome aberration formation during the cell cycle, and as a biological dosimeter for ionising irradiation. The published data suggest a significance of PCC in risk assessment. In order to investigate the significance of PCC in (cancer) risk assessment, we studied the chemical exposure-induced PCC frequencies in 400 Hungarian subjects including 188 control donors and 212 subjects occupationally exposed to different genotoxic chemicals, such as acrylonitrile (ACN) and/or dimethylformamide (DMF), benzene, cytostatic drugs, ethylene oxide (ETO), mixed exposure in rubber industry, mixed organic solvents including CCl4, hot oil mist, bitumen, and polychlorinated biphenyls (PCB). Mitotic chromosomes were prepared by the standard methods and 100 metaphases per donor were scored. PCC data were compared with the obtained structural and numeric chromosome aberration frequencies. Here we present preliminary, chemical exposure-induced PCC frequency data. In the 101 controls nobody, while in the 87 industrial controls only 1 donor (0,01 %) had PCC. No PCC was found in oil mist exposure and among Adriamycin synthesisers. Similarly, no significant PCC increases were observed with benzene and polychlorinated biphenyl and mixed exposures, as well as in Adriamycin fermentators or hospital nurses exposed to ethylene oxide. Increased (P<0.05) PCC frequencies were observed in the following exposed groups: mixed industrial solvents (including aromatic solvents and CCl4), bitumen (PAH), acrylonitrile and dimethyl-formamide, and hospital nurses with cytostatic drugs. The results suggest that certain occupational exposures can increase the PCC frequency in human PBLs. The investigation of the significance of PCC in cancer risk assessment needs further studies which are in progress."