Publications by authors named "Valerii N Rakitskii"

13 Publications

  • Page 1 of 1

Mutagenicity evaluation of pesticide analogs using standard and 6-well miniaturized bacterial reverse mutation tests.

Toxicol In Vitro 2020 Dec 23;69:105006. Epub 2020 Sep 23.

The Federal Budgetary Establishment of Science «Federal Scientific Center of Hygiene named after F.F. Erisman» of Federal Service for Surveillance on Consumer Rights Protection and Human Wellbeing, Semashko Str. 2, Mytishchi 141014, Russian Federation.

The Ames test is widely used in the mutagenicity evaluation of new and existing chemicals as a part of a compound selection strategy, regulatory control, the equivalence assessment, carcinogenic potential measurement etc. Intensification of the chemical industry and synthesis of plenty of new molecules has led to the necessity of tests with a higher throughput capacity. The 6-well miniaturized bacterial reverse mutation test and the standard Ames test were compared using 14 technical grade active ingredients (TGAIs) of pesticides. With some exceptions, the responses obtained in the miniscreen Ames are similar to those seen in the standard method: 4 overall test outcomes were negative and 9 were positive in both test versions, but 1 discordant result between the miniscreen and standard version. Comparison of the standard and the miniscreen Ames test resulted in 98% of concordance across five strains and conditions (±S9). The overall judgment is that the miniscreen Ames test can be used to assess the mutagenicity of pesticide analogs. It has the advantage of decreasing the number of materials and animals (for S9) and keeping a high-test performance.
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http://dx.doi.org/10.1016/j.tiv.2020.105006DOI Listing
December 2020

Genotoxicity of mixture of imidacloprid, imazalil and tebuconazole.

Toxicol Rep 2020 30;7:1090-1094. Epub 2020 Aug 30.

Centre of Toxicology Science & Research, Medical School, University of Crete, Heraklion, Crete, Greece.

Genotoxicity of the mixture of generic pesticides imidacloprid + imazalil + tebuconazole in a ratio of 14.0/1.7/1.0 by weight was assessed using Ames test () and micronucleus test on mammalian bone marrow erythrocytes (CD-1 mice) supporting the data creation for the Real Life Risk Simulation (RLRS) approach. This pesticides' combination is used in the commercial formulation for seed treatment in advance of or immediately before sowing. Tested pesticides' technical grade active ingredients (TGAIs) showed no evidence of genotoxicity upon separate treatments. In combination, the three pesticides demonstrated negative results in the Ames test but induced a statistically significant, dose-depended increase in MN-PCEs in mice bone marrow at doses lower than those used separately. The observed effect may be mediated by the synergistic action of the tested TGAIs, their metabolites or impurities.
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http://dx.doi.org/10.1016/j.toxrep.2020.08.021DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7484519PMC
August 2020

Parkinson's disease and pesticides: Are microRNAs the missing link?

Sci Total Environ 2020 Nov 29;744:140591. Epub 2020 Jun 29.

Department of Neurology, Laboratory of Neurogenetics, University Hospital of Larissa, Greece, Faculty of Medicine, School of Health Sciences, University of Thessaly, Larissa, Greece.

Parkinson's disease (PD) is a common neurodegenerative disorder that leads to significant morbidity and decline in the quality of life. It develops due to loss of dopaminergic neurons in the substantia nigra pars compacta, and among its pathogenic factors oxidative stress plays a critical role in disease progression. Pesticides are a broad class of chemicals widely used in agriculture and households for the protection of crops from insects and fungi. Several of them have been incriminated as risk factors for PD, but the underlying mechanisms have yet to be fully understood. MicroRNAs (miRNAs) are small, non-coding RNA molecules that play an important role in regulating mRNA translation and protein synthesis. miRNA levels have been shown to be affected in several diseases as well. Since the studies on the association between pesticides and PD have yet to reach definitive conclusions, here we review recent evidence on deregulated microRNAs upon pesticide exposure, and attempt to find an overlap between miRNAs deregulated in PD and pesticides, as a missing link between the two, and enhance future research in this direction.
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http://dx.doi.org/10.1016/j.scitotenv.2020.140591DOI Listing
November 2020

Olive oil with high polyphenolic content induces both beneficial and harmful alterations on rat redox status depending on the tissue.

Toxicol Rep 2020 13;7:421-432. Epub 2020 Feb 13.

Department of Biochemistry and Biotechnology, University of Thessaly, Viopolis, Mezourlo, 41500 Larissa, Greece.

Olive oil (OO) possesses a predominant role in the diet of Mediterranean countries. According to a health claim approved by the European Food Safety Authority, OO protects against oxidative stress‑induced lipid peroxidation in human blood, when it contains at least 5 mg of hydroxytyrosol and its derivatives per 20 g. However, studies regarding the effects of a total OO biophenols on redox status are scarce and either observational and do not provide a holistic picture of their action in tissues. Following a series of screening tests an OO containing biophenols at 800 mg/kg of OO was administered for 14 days to male Wistar rats at a dose corresponding to 20 g OO/per day to humans. Our results showed that OO reinforced the antioxidant profile of blood, brain, muscle and small intestine, it induced oxidative stress in spleen, pancreas, liver and heart, whereas no distinct effects were observed in lung, colon and kidney. The seemingly negative effects of OO follow the recently formulated idea in toxicology, namely the real life exposure scenario. This study reports that OO, although considered a nutritional source rich in antioxidants, it exerts a tissues specific action when administered .
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http://dx.doi.org/10.1016/j.toxrep.2020.02.007DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7052070PMC
February 2020

Does SCFD1 rs10139154 Polymorphism Decrease Alzheimer's Disease Risk?

J Mol Neurosci 2019 Oct 2;69(2):343-350. Epub 2019 Jul 2.

Department of Neurology, Laboratory of Neurogenetics, University of Thessaly, University Hospital of Larissa, Biopolis, Mezourlo Hill, 41100, Larissa, Greece.

Α number of genetic variants have been associated with Alzheimer's disease (AD) susceptibility. Sec1 family domain-containing protein 1 (SCFD1) gene polymorphism rs10139154 has recently been implicated in the risk of developing amyotrophic lateral sclerosis (ALS). Similarities in the pathogenetic cascade of both diseases have also been described. The present study was designed to evaluate the possible contribution of SCFD1 rs10139154 to AD. A total of 327 patients with AD and an equal number of healthy controls were included in the study and genotyped for rs10139154. With logistic regression analyses, rs10139154 was examined for the association with the risk of developing AD. In the recessive mode, SCFD1 rs10139154 was associated with a decreased risk of developing AD (odds ratio (OR) (95% confidence interval (CI)) = 0.63 (0.40-0.97), p = 0.036). The current study provides preliminary evidence of the involvement of SCFD1 rs10139154 in the risk of developing AD.
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http://dx.doi.org/10.1007/s12031-019-01363-3DOI Listing
October 2019

Indicator PCBs in farmed and wild fish in Greece - Risk assessment for the Greek population.

Food Chem Toxicol 2019 May 18;127:260-269. Epub 2019 Mar 18.

Centre of Toxicology Science and Research, University of Crete, School of Medicine, Crete, Greece.

Health benefits of fish consumption could be counterbalanced by the intake of contaminants after long term fish consumption, burdened even in trace levels. The presence of the indicator PCBs (NDL-PCBs and PCB 118) in farmed and wild seabream and seabass was evaluated. For the determination of PCB, a GC-MS method was developed and evaluated. The association of PCB accumulation in fish with seasonality, locality, production mode and species was also investigated. A new approach for the risk characterisation after exposure to NDL-PCB through fish consumption in Greece was developed, based on the real exposure and the permitted maximum levels of both aggregated dietary exposure and exposure through fish consumption. PCB levels determined in fish were below established permitted limits (6.24 ng/g 95th percentile), while PCB levels and congener distribution varied significantly between farmed and wild fish (p = 0.001). Seasonality was highlighted as an important factor affecting NDL-PCBs accumulation, with high levels coinciding with the reproduction period of each species. Differences were also depicted for sampling sites, with PCB 118 presenting significantly higher values in open seas while NDL-PCB congeners in closed seas. Risk assessment of NDL-PCB intake through fish consumption corrected for the aggregated exposure revealed no risk for the consumers.
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http://dx.doi.org/10.1016/j.fct.2019.03.027DOI Listing
May 2019

Six months exposure to a real life mixture of 13 chemicals' below individual NOAELs induced non monotonic sex-dependent biochemical and redox status changes in rats.

Food Chem Toxicol 2018 May 3;115:470-481. Epub 2018 Apr 3.

Center of Toxicology Science & Research, Medical School, University of Crete, Heraklion, Crete, Greece. Electronic address:

This study assessed the potential adverse health effects of long-term low-dose exposure to chemical mixtures simulating complex real-life human exposures. Four groups of Sprague Dawley rats were administered mixtures containing carbaryl, dimethoate, glyphosate, methomyl, methyl parathion, triadimefon, aspartame, sodium benzoate, calcium disodium ethylene diamine tetra-acetate, ethylparaben, butylparaben, bisphenol A, and acacia gum at doses of 0, 0.25, 1 or 5 times the respective Toxicological Reference Values (TRV): acceptable daily intake (ADI) or tolerable daily intake (TDI) in a 24 weeks toxicity study. Body weight gain, feed and water consumption were evaluated weekly. At 24 weeks blood was collected and biochemistry parameters and redox status markers were assessed. Adverse effects were observed on body weight gain and in hepatotoxic parameters such as the total bilirubin, alanine aminotransferase (ALT) and alkaline phosphatase (ALP), especially in low dose and affecting mainly male rats. The low dose group showed increased catalase activity both in females and males, whereas the high dose group exhibited decreased protein carbonyl and total antioxidant capacity (TAC) levels in both sex groups. Non-monotonic effects and adaptive responses on liver function tests and redox status, leading to non-linear dose-responses curves, are probably produced by modulation of different mechanisms.
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http://dx.doi.org/10.1016/j.fct.2018.03.052DOI Listing
May 2018

Staphylococcus aureus colonisation in patients from a primary regional hospital.

Mol Med Rep 2017 Dec 10;16(6):8771-8780. Epub 2017 Oct 10.

Department of Microbiology, University of Medicine and Pharmacy of Craiova, 200349 Craiova, Romania.

Staphylococcus aureus (SA or S. aureus) is a common pathogen that leads to local and systemic infections in communitarian and hospitalised patients. Staphylococcus colonizing nasal or pharyngeal sites can become virulent and cause severe infections. In this study, we collected 322 pharyngeal exudates and 142 nasal exudates from hospitalised and outpatients for screening purposes. The carriage rates in the pharynx were 27.06% for S. aureus, 11.55% for methicillin‑resistant S. aureus (MRSA) and 5.61% for methicillin‑oxacillin resistant S. aureus (MORSA). The carriage rates in the nose were 35.38% for S. aureus, 18.46% for MRSA and 13.85% for MORSA. The median multiple antibiotic resistance (MAR) index of SA was 33.33%. The MAR of MRSA was significantly higher than that of methicillin-susceptible strains (MSSA) (45.45% vs. 18.75%, P<0.0001) and the MAR of MORSA was 57.14%. Hierarchical clustering analysis revealed differences in the resistance of methicillin-sensitive, MRSA and MORSA strains. On the whole, our study demonstrates the pattern of distribution of nasal and pharyngeal colonisation with SA, MRSA and MORSA in adults vs. children, inpatients vs. outpatients, ICU patients vs. non‑ICU patients, and females vs. males, which can be used for adjusting the screening and decontamination protocols in a hospital. SA is a pervasive pathogen with constantly changing trends in resistance and epidemiology and thus requires constant monitoring in healthcare facilities.
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http://dx.doi.org/10.3892/mmr.2017.7746DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5779955PMC
December 2017

CYP polymorphisms and pathological conditions related to chronic exposure to organochlorine pesticides.

Toxicol Rep 2017 26;4:335-341. Epub 2017 May 26.

Research Group of Clinical Pharmacology and Pharmacogenomics, Faculty of Pharmacy, School of Health Sciences, National and Kapodistrian University of Athens, Greece.

The association between genetic variations in the cytochrome P450 (CYP) family genes and pathological conditions related to long-term exposure to organochlorine compounds (OCs) deserves further elucidation. OCs are persistent organic pollutants with bioaccumulative and lipophilic characteristics. They can act as endocrine disruptors and perturb cellular mechanisms. Prolonged exposure to OCs has been associated with different pathological manifestations. CYP genes are responsible for transcribing enzymes essential in xenobiotic metabolism. Therefore, polymorphisms in these genetic sequences a. alter the metabolic pathways, b. induce false cellular responses, and c. may provoke pathological conditions. The main aim of this review is to define the interaction between parameters a, b and c at a mechanistic/molecular level, with references in clinical cases.
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http://dx.doi.org/10.1016/j.toxrep.2017.05.007DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5615117PMC
May 2017

Pesticides, polychlorinated biphenyls and polycyclic aromatic hydrocarbons in cerebrospinal fluid of amyotrophic lateral sclerosis patients: a case-control study.

Environ Res 2017 05 10;155:261-267. Epub 2017 Mar 10.

Department of Forensic Sciences and Toxicology, University of Crete, 71409 Heraklion, Greece.

Neurotoxic chemicals including several pesticides have been suggested to play a role in the etiology of amyotrophic lateral sclerosis (ALS). We investigated the relation between organochlorine pesticides and their metabolites (OCPs), polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs) in the etiology of sporadic ALS, determining for the first time their levels in cerebrospinal fluid as indicator of antecedent exposure. We recruited 38 ALS patients and 38 controls referred to an Italian clinical center for ALS care, who underwent a lumbar puncture for diagnostic purposes between 1994-2013, and had 1mL of cerebrospinal fluid available for the determination of OCPs, PCBs and PAHs. Many chemicals were undetectable in both case and control CSF samples, and we found little evidence of any increased disease risk according to higher levels of exposure. Among males >60 years, we found a slight but statistically very unstable increased ALS risk with higher levels of the congener PCB 28 and the OCP metabolite p,p'-DDE. Overall, these results do not suggest an involvement of the neurotoxic chemicals investigated in this study in disease etiology, although small numbers limited the precision of our results.
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http://dx.doi.org/10.1016/j.envres.2017.02.025DOI Listing
May 2017

Long-term exposure to cypermethrin and piperonyl butoxide cause liver and kidney inflammation and induce genotoxicity in New Zealand white male rabbits.

Food Chem Toxicol 2016 Aug 16;94:250-9. Epub 2016 Jun 16.

Laboratory of Toxicology, Medical School, University of Crete, Voutes, 71409 Heraklion, Crete, Greece. Electronic address:

Cypermethrin (CY) is a frequently used class II pyrethroid pesticide, while piperonyl butoxide (PBO) plays a major role in the pesticide formulation of synthetic pyrethroids. Synthetic pyrethroids are metabolized in mammals via oxidation and ester hydrolysis. PBO can prevent the metabolism of CY and enhances its pesticide effect. While this potentiation effect reduces the amount of pesticide required to eliminate insects, it is not clear how this mixture affects mammals. In our in vivo experiment, New Zealand white male rabbits were exposed to low and high doses of CY, PBO, and their combinations, for 4 months. Genotoxicity and cytotoxicity were monitored by measuring binucleated cells with micronuclei (BNMN), micronuclei (MN) and the cytokinesis block proliferation index (CBPI) in lymphocytes. After two months of exposure, a statistically significant increase in the frequency of BNMN was observed for all exposed animals (p < 0.001) in a dose-dependent way. MN were significantly elevated compared to controls (p < 0.001), with high dose groups reaching a 442% increase when co-exposed. BNMN and MN continued to increase after four months. Histopathological examination of lesions showed damage involving inflammation, attaining lymphoplasmatocytic infiltration in the high dose groups. Both CY and PBO cause liver and kidney inflammation and induce genotoxicity.
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http://dx.doi.org/10.1016/j.fct.2016.06.016DOI Listing
August 2016

Long-term exposure of rabbits to imidaclorpid as quantified in blood induces genotoxic effect.

Chemosphere 2016 Apr 5;149:108-13. Epub 2016 Feb 5.

Center of Toxicology Science & Research, Division of Morphology, Medical School, University of Crete, Voutes Campus, Heraklion, 71003, Crete, Greece. Electronic address:

The present in-vivo study focuses on the genotoxic effect of the neonicotinoid pesticide imidacloprid (IMI) in rabbits. The purpose of the study was to establish a possible relationship between exposure to the pesticide (dose and duration) and genotoxicity. Furthermore, an analytical method for the simultaneous determination of IMI and its major metabolite 6-chloronicotinic acid (6-ClNA) in blood was developed and validated. The isolation of the two analytes from blood was performed by liquid-liquid extraction with dichloromethane. Analysis was performed by Liquid Chromatography - Atmospheric Pressure Chemical Ionization - Mass Spectrometry (LC-APCI-MS). The method was applied on the determination of IMI and 6-ClNA in serum samples obtained from rabbits fed with the insecticide at two low doses. Furthermore, parameters of genotoxicity and cytotoxicity were evaluated by measuring binucleated cells with micronuclei (BNMN), micronuclei (MN) and the Cytokinesis Block Proliferation Index (CBPI), in lymphocytes of exposed rabbits. The results revealed a genotoxic effect of IMI for both exposed groups. There were statistically significant differences in the frequencies of BNMN and MN between control and exposed groups but there was no dose-dependence, neither time-dependence of the genotoxic effect for the administered doses. This is the first time that long term exposure to IMI in rabbits was studied for the determination of its genotoxic effect. The genotoxic effect of IMI as it is depicted by the current study is in accordance with previous studies.
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http://dx.doi.org/10.1016/j.chemosphere.2016.01.040DOI Listing
April 2016