Tracing the movement of persistent organic pollutants at a high-mountain sampling site by chemometric assessment.

The main objective of the present study was to determine and differentiate the concentration levels, to define the probable sources of persistent organic pollutants (POPs) pollution in the atmospheric air and their seasonal variations in Bulgaria, on the high mountain peak Moussala, Rila Mountain. The study was based on the obtained results from the passive monitoring of POPs in 2014-2017. During this period, the measurements of POPs were performed with passive samplers, advanced instrumental methods analytically determined the concentrations of PAHs, and the analysis of the obtained data was performed by the multivariate statistical analysis (cluster, factor and time-series analysis). It is shown that the POPs species could be correctly classified according to their chemical nature into several patterns of similarity and their concentration profile depends on the annual season.

How can the natural radiation background affect DNA integrity in angiosperm plant species at different altitudes in Rila Mountain (Southwest Bulgaria)?

Climate changes and anthropogenic factors are the main factors contributing to the destruction of natural ecosystems. The aim of this study was to investigate the extent to which wild plants adapt to UV, gamma background, and gross beta activity, as well as the possible damage that can be recorded in plants growing at different altitudes in Rila Mountain. We used physicochemical, cytogenetic, and molecular methods. Our investigations were done on the nine plant species characteristic of the ecosystems in Rila Mountain at three altitudes: 1500 m, 1782 m, and 2925 m. The registered beta activity in the plants did not depend on the altitude of the habitats. Our results showed that wild plant species differ in their tolerance to the combined effect of UV and IR radiation as well as climate factors. The genotype plays a more important role than the difference in the habitat altitude. The comet assay adapted by us for these plant species showed that the DNA of Epilobium angustifolium L. (Onagraceae) growing at 1500 m was more susceptible to damage than that of Dactylis glomerata L. (Poaceae). Both these species growing at 1782 m did not show any increase in DNA damage evaluated as the level of DNA migration. The level of DNA damage in Pedicularis orthantha Griseb. (Orobanchaceae) at 2925 m was comparable to that at a lower altitude. Regarding the formation of micronuclei, grass species were more sensitive to UV- and IR-induced DNA damage than cereals. Our data imply the existence of specific protective mechanisms developed by plants to overcome DNA damage induced by stress factors.

Search for the presence of occult hepatitis C in patients with treatment-induced viral clearance using an ultrasensitive assay.

Introduction: Occult hepatitis C is defined by the presence of virus in the peripheral blood mononuclear cells (PBMCs) and/or liver cells, in the absence of serum viremia. Objective: To detect the persistence of occult hepatitis C in hemodialysis (HD) patients and patients without renal disease (non-renal) with treatment-induced clearance of hepatitis C virus (HCV) infection, using assays with a very low detection limit of viremia. Methods: A group of 13 HD patients and a group of 43 non-renal patients, with treatment-induced HCV infection clearance were investigated in the study. The HD patients were treated with pegylated interferon alpha (PEG-IFN-α) only, while the non-renal patients were treated with a combination therapy of PEGIFN- α and ribavirin. Detection of a possible persistence of HCV RNA in the PBMCs and plasma samples was assessed by an ultrasensitive reverse transcription polymerase chain reaction (RT-PCR) assay (2 IU/ml). Results: HCV RNA was not detected in the PBMCs and plasma samples of HD patients and of non-renal patients, when assessed by the ultrasensitive RT-PCR assay. Conclusion: When a sensitive RT-PCR assay was applied, to determine if treatment induced clearance of HCV infection had been successful, occult hepatitis C could not be detected by an ultrasensitive assay, neither in HD nor in non-renal patients.

Genetic predictors of the response to the treatment of hepatitis C virus infection.

The genome-wide association studies have identified a strong association between interleukin 28B (IL28B) gene polymorphisms and the response to treatment in patients with hepatitis C virus (HCV) infection. The aim of the study was to evaluate the association between three most widely studied IL28B gene polymorphisms and the response to antiviral treatment of chronic hepatitis C. We performed the genotyping of the three IL28B gene polymorphisms: rs12979860, rs8099917, and rs12980275 in 72 Caucasian patients with chronic hepatitis C, previously treated with the combination therapy of pegylated interferon alpha (PEGIFN α) and ribavirin (RBV). The patients included in the study had finished the treatment regimen at least 6 months before enrolling in the study. We used the sustained viral response (SVR) for the evaluation of the effectiveness of the antiviral treatment, and it was tested with an assay with a sensitivity of 20 IU/mL. An SVR was achieved in 59.7% (43/72) of the treated patients. The three IL28B gene polymorphisms (CC genotype of rs12979860, TT genotype of rs8099917, and AA genotype of rs12980275) were associated with the SVR (p=0.029, p=0.016, and p=0.028, respectively) in the study patients with chronic hepatitis C treated with the combination therapy of PEGIFN α and RBV. The association of IL28B gene polymorphisms with the treatment response points to the possibility of personalized medicine for the treatment of HCV infection.