Monitoring of Organochlorine Pesticides (OCP) in Hair Samples of Wild Herbivorous Mammals Living in Remote and Protected Areas of the Far East and Siberia of Russia.

Monitoring wildlife exposure to biological hazards is a critical component of the wildlife risk assessment. In this study 38 hair samples were collected from 8 different species from ten districts of Russian Far East and Siberia and analysed for the presence of organochlorine pesticides (OCP). 50% of the samples were contaminated with - p, p'-DDT, α-HCH and DDD. DDT was the main contaminant found in 13 sample at concentrations range of 14.3 to 369.5 pg/mg hair, mean 91.9 ± 89.7 pg/mg. α-HCH was detected in three samples with the concentrations range 29.9-180.2 pg/mg. The p, p'-DDD was found only in one hair sample of Siberian roe deer from Altai region at 52.6 pg/mg. The exposure level is depended on animals habitat location. The most contaminated region is Terney district which is in the proximity to the borders with China and North Korea where OCP are still in use.

Behavioral impacts of a mixture of six pesticides on rats.

Pesticides can potentially contribute to the development of numerous neurodegenerative diseases. This study evaluates the effects of a six-pesticide mixture at doses around the no-observed-adverse-effectlevels (0 × NOAEL, control) and 0.25, 1 and 5 × NOAEL on behavior of Wistar rats. After 3, 6 and 12 months, rats were observed for neurobehavioral changes using the techniques of elevated plus maze and universal problemchamber, and the experiment was conducted thrice. The 3-month exposure revealed a decrease in the cognitive ability at the dose of 5 × NOAEL, and a dose-dependent research activity and anxiety. The 6-month exposurerevealed non-monotonic effects on the cognitive ability, with a decrease by 0.25 and 5 × NOAEL, as well as non-monotonic effects on anxiety, withan increase by 0.25 and 1 × NOAEL. A decrease was also observed in research activity at 5 × NOAEL. However, the 12-month exposure resulted to an increase in cognitive ability by 0.25 × NOAEL and in anxiety by 1 × NOAEL, as well as to a dose-dependent research activity. Repeating the trial showed that the cognitive ability increased from one trial to another, while the researching activity decreased and the anxiety increased by 0× NOAEL. In the groups exposed to pesticides mixture, the trends were different, showing that the exposure to pesticides combined with repeated trials, also influence the response of the animals. The resultsdemonstrate the occurrence of several dose-dependent behavioral responses, with negative effects occurring at doses that are considered safe. This study provides novel insights about time-dependent mixtures biology, and an important perspective to consider when conducting risk assessments.

Urinary microRNAs as potential biomarkers of pesticide exposure.

MicroRNAs (miRNAs) are post-transcriptional regulators that silence messenger RNAs. Because miRNAs are stable at room temperature and long-lived, they have been proposed as molecular biomarkers to monitor disease and exposure status. While urinary miRNAs have been used clinically as potential diagnostic markers for kidney and bladder cancers and other diseases, their utility in non-clinical settings has yet to be fully developed. Our goal was to investigate the potential for urinary miRNAs to act as biomarkers of pesticide exposure and early biological response by identifying the miRNAs present in urine from 27 parent/child, farmworker/non-farmworker pairs (16FW/11NFW) collected during two agricultural seasons (thinning and post-harvest) and characterizing the between- and within-individual variability of these miRNA epigenetic regulators. MiRNAs were isolated from archived urine samples and identified using PCR arrays. Comparisons were made between age, households, season, and occupation. Of 384 miRNAs investigated, 297 (77%) were detectable in at least one sample. Seven miRNAs were detected in at least 50% of the samples, and one miRNA was present in 96% of the samples. Principal components and hierarchical clustering analyses indicate significant differences in miRNA profiles between farmworker and non-farmworker adults as well as between seasons. Six miRNAs were observed to be positively associated with farmworkers status during the post-harvest season. Expression of five of these miRNA trended towards a positive dose response relationship with organophosphate pesticide metabolites in farmworkers. These results suggest that miRNAs may be novel biomarkers of pesticide exposure and early biological response.

Comparison of biological effects of electromagnetic fields with pulse frequencies of 8 and 50 Hz on gastric smooth muscles.

The influence of electromagnetic fields (EMFs) with rectangular pulse frequencies of 8 and 50 Hz and flux density of 25 µT on contraction, nitric oxide/nitrite synthesis, and intracellular calcium concentration in the gastric smooth muscles of rats was investigated. An approximately 8-Hz field reduced the fast component of contraction induced by KCl depolarization and slowed down the time to reach the maximum of the slow component of contraction, whereas the 50-Hz field increased the fast and slow components and accelerated the time to reach the maximum of the slow component of contraction. After turning off the EMF, the force and character of contraction returned to the control values. In addition, the 8-Hz field increased nitric oxide/nitrite synthesis in the excited smooth muscle tissue with KCl depolarization, while the 50-Hz field had no significant effect. 8- and 50-Hz fields had no significant effects on nitric oxide/nitrite production in non-stimulated tissue. However, the 50-Hz field significantly increased the basic intracellular calcium concentration in smooth muscle cells (SMC) in a time-dependent manner, whereas the 8-Hz field only slightly increased calcium levels. Thus, we showed that responses of gastric smooth muscles to EMFs are pulse-frequency dependent.