The investigation of the toxicity of organophosphorus flame retardants (OPFRs) by using in silico toxicity prediction platform ProTox- 3.0.

From the past to the present, many chemicals have been used for the purpose of flame retardant. Due to PBDEs' (Polybrominated diphenyl ether) lipophilic and accumulative properties, some of them are banned from the market. As an alternative to these chemicals, OPFRs (organophosphorus flame retardants) have started to be used as flame retardants. In this article, acute toxicity profiles, mutagenicity, carcinogenicity, blood-brain barrier permeability, ecotoxicity and nutritional toxicity as also AHR, ER affinity and MMP, aromatase affinity, CYP2C9, CYP3A4 interaction of the of 16 different compounds of the OPFRs were investigated using a computational toxicology method; ProTox- 3.0. According to our results, eight compounds were found to be active in terms of carcinogenic effect, whereas two compounds were found to be active for mutagenicity. On the other hand, all compounds were found to be active in terms of blood-barrier permeability. Fourteen compounds and four compounds are found to have ecotoxic and nutritional toxic potency, respectively. Eight compounds were determined as active to AhR, and four chemicals were found to be active in Estrogen Receptor alpha. Eight chemicals were found to be active in terms of mitochondrial membrane potency. Lastly, three chemicals were found to be active in aromatase enzymes. In terms of CYP interaction potencies, eight compounds were found to be active in both CYP2C9 and CYP3A4. This research provided novel insights into the potential toxic effects of OPFRs. However, further studies are needed to evaluate their toxicity. Moreover, these findings lay the groundwork for in vitro and in vivo toxicity research.

Combinative ex vivo studies and in silico models ProTox-II for investigating the toxicity of chemicals used mainly in cosmetic products.

Human data on remains sparse and of varying quality and reproducibility. Ex vivo experiments and animal experiments currently is the most preferred way to predict the skin sensitization approved by the regulatory agencies across the world. However, there is a constant need and demand to reduce animal experiments and provide the scope of alternative methods to animal testing. In this study, we have compared the predictive performance of the published computational tools such as ProTox-II, SuperCYPsPred with the data obtained from ex-vivo experiments. From the results of the retrospective analysis, it can be observed that the computational predictions are in agreement with the experimental results. The computational models used here are generative models based on molecular structures and machine learning algorithms and can be applied also for the prediction of skin sensitization. Besides prediction of the toxicity endpoints, the models can also provide deeper insights into the molecular mechanisms and adverse outcome pathways (AOPs) associated with the chemicals used in cosmetic products.

Utilization of the ex vivo LLNA: BrdU-ELISA to distinguish the sensitizers from irritants in respect of 3 end points-lymphocyte proliferation, ear swelling, and cytokine profiles.

Dermal exposure to chemicals may result in allergic or irritant contact dermatitis. In this study, we performed ex vivo local lymph node assay: bromodeoxyuridine-enzyme-linked immunosorbent assay (LLNA: BrdU-ELISA) to compare the differences between irritation and sensitization potency of some chemicals in terms of the 3 end points: lymphocyte proliferation, cytokine profiles (interleukin 2 [IL-2], interferon-γ (IFN-γ), IL-4, IL-5, IL-1, and tumor necrosis factor α [TNF-α]), and ear swelling. Different concentrations of the following well-known sensitizers and irritant chemicals were applied to mice: dinitrochlorobenzene, eugenol, isoeugenol, sodium lauryl sulfate (SLS), and croton oil. According to the lymph node results; the auricular lymph node weights and lymph node cell counts increased after application of both sensitizers and irritants in high concentrations. On the other hand, according to lymph node cell proliferation results, there was a 3-fold increase in proliferation of lymph node cells (stimulation index) for sensitizer chemicals and SLS in the applied concentrations; however, there was not a 3-fold increase for croton oil and negative control. The SLS gave a false-positive response. Cytokine analysis demonstrated that 4 cytokines including IL-2, IFN-γ, IL-4, and IL-5 were released in lymph node cell cultures, with a clear dose trend for sensitizers whereas only TNF-α was released in response to irritants. Taken together, our results suggest that the ex vivo LLNA: BrdU-ELISA method can be useful for discriminating irritants and allergens.

Investigation of allergenicity of some cosmetic mixtures by using ex vivo local lymph node assay-BrdU endpoints.

BACKGROUND: Balsam of Peru and fragrance mix are commonly used in cosmetic products. Allergy to fragrance is the most common cause of cosmetic contact dermatitis. METHODS: In the present study, ex vivo local lymph node assay-5-bromo-2'-deoxyuridine (LLNA-BrdU) was used to evaluate the dermal sensitization potential of these cosmetic mixtures. The stimulation index values and estimated concentration (EC3) values were calculated and the potency classification was found for each mixture. At the same time, in order to measure the irritant effect without having to use additional animals, a combination of ex vivo LLNA-BrdU and the irritancy assay was conducted. RESULTS: Th1 [interleukin (IL)-2, interferon-γ] and Th2 cytokine (IL-4, IL-5) releases from lymph node cell culture were investigated as non-radioactive endpoints. According to the results of ex vivo LLNA-BrdU assays, EC3 values were found to be 3.09% (moderate) for balsam of Peru and 4.44% (moderate) for fragrance mix. Cytokine analysis results indicate that both Th1 and Th2 cytokines are involved in the regulation of murine contact allergy and can be considered as useful endpoints. CONCLUSION: In conclusion, according to our results, fragrance mix and balsam of Peru can be considered as moderate sensitizers; however, in high concentrations, both of them have irritation properties. The cytokines investigated can be considered as the endpoints of the ex vivo LLNA-BrdU assay.

Short overview on the relevance of microRNA-reactive oxygen species (ROS) interactions and lipid peroxidation for modulation of oxidative stress-mediated signalling pathways in cancer treatment.

OBJECTIVES: Modulation of oxidative stress-mediated signalling pathways is constantly getting more attention as a valuable therapeutic strategy in cancer treatment. Although complexity of redox signalling pathways might represent a major hurdle, the development of advanced -omics technologies allow thorough studies on cancer-specific biology, which is essential to elucidate the impact of these signalling pathways in cancer cells. The scope of our review is to provide updated information about recent developments in cancer treatment. KEY FINDINGS: In recent years identifying oxidative stress-mediated signalling pathways is a major goal of cancer research assuming it may provide novel therapeutic approaches through the development of agents that may have better tissue penetration and therefore affect specific redox signalling pathways. In this review, we discuss some recent studies focussed on the modulation of oxidative stress-related signalling pathways as a novel anti-cancer treatment, with a particular emphasis on the induction of lipid peroxidation. CONCLUSIONS: Characterization and modulation of oxidative stress-mediated signalling pathways and lipid peroxidation products will continue to foster novel interest and further investigations, which may pave the way for more effective, selective, and personalized integrative biomedicine treatment strategies.

Correlation of Ochratoxin A exposure to urinary levels of 8-hydroxydeoxyguanosine and malondialdehyde in a Turkish population.

Ochratoxin A is one of the most abundant food- contaminating mycotoxins in the world that is immunosuppressive, genotoxic, teratogenic and carcinogenic. Malondialdehyde is a naturally occurring product of lipid peroxidation that is mutagenic and carcinogenic. 8-Hydroxydeoxyguanosine is produced during the interaction of reactive oxygen species and DNA. In this study, Ochratoxin A, malondialdehyde and 8-Hydroxydeoxyguanosine levels of individuals in the study group were measured and results were correlated with each other. Additionally, the correlation of biomarker levels to smoking habit, alcohol and coffee consumption, age and gender of individuals was investigated. As a result of these assessments, a significant correlation was observed between Ochratoxin A exposures and malondialdehyde and 8-Hydroxydeoxyguanosine levels.

Cytogenetic monitoring of coal workers and patients with coal workers' pneumoconiosis in Turkey.

Occupational exposure to coal dust causes coal workers' pneumoconiosis (CWP), which is a chronic inflammatory and fibrotic lung disease. Recently, chronic inflammation has been accepted as a crucial factor in the pathogenesis of neoplasia. The chronic inflammation provides dynamic setting for oxidative stress and formation of free radicals. Interaction of reactive oxygen species (ROS) with DNA augments the likelihood of DNA structural and transcriptional errors. The purpose of this study was to investigate the genotoxic risk in pneumoconiotic patients and in those with occupational exposure to coal dust. Therefore, sister chromatid exchange (SCE) and micronucleus (MN) tests were performed in Turkish CWP patients, coal workers, and an unexposed control group. Both SCE and MN frequencies in CWP patients were found significantly higher than in coal worker and unexposed groups. There were no differences between SCE and MN frequencies of coal worker and unexposed groups. On the other hand, no correlation between SCE frequency, duration of exposure, and age was observed in all three groups. There was also no effect of smoking on the frequencies of SCE and MN in the groups. Based on these results, it might be suggested that development of CWP leads to a significant induction of cytogenetic damage in peripheral lymphocytes of CWP patients. This is the first report on CWP patients with elevated cytogenetic endpoints. Further, a larger follow-up study is warranted.

Allergenicity evaluation of fragrance mix and its ingredients by using ex vivo local lymph node assay-BrdU endpoints.

The present studies were performed to compare the differences between sensitization potency of fragrance mix and its ingredients (oak moss absolute, isoeugenol, eugenol, cinnamal, hydroxycitronellal, geraniol, cinnamic alcohol, alpha amyl cinnamal), by using ex vivo LLNA-BrdU ELISA. The SI and EC3 values were calculated and potency classification was found for the mixture and for each ingredients. TH1 cytokines (IL-2, IFN-γ) and TH2 cytokines (IL-4, IL-5) releases from lymph node cell culture were also investigated as contact sensitization endpoints. The EC3 values were calculated and the potency of contact sensitization were classified for fragrance mix, oak moss absolute, isoeugenol, eugenol, cinnamal, hydroxycitronellal, geraniol, cinnamic alcohol, alpha amyl cinnamal respectively: 4.4% (moderate), 3.4% (moderate), 0.88% (strong), 16.6% (weak), 1.91% (moderate), 9.77% (moderate), 13.1% (weak), 17.93% (weak), 7.74% (moderate). According to our results it should be concluded that exposure to fragrance mix does not constitute an evidently increased hazard compared to exposure to each of the eight fragrance ingredients separately. Cytokine analyses results indicate that both TH1 and TH2 cytokines are involved in the regulation of murine contact allergy and can be considered as useful endpoints.

Evaluation of non-radioactive endpoints of ex vivo local lymph node assay-BrdU to investigate select contact sensitizers.

The present study sought to verify the utility of the non-radioactive endpoints LLNA BrdU (5-bromo-2'-deoxyuridine) ex vivo incorporation and cytokine release using auricular lymph node cells isolated from BALB/c mice topically treated with a strong (formaldehyde or p-phenylene-diamine [PPD]), moderate sensitizer (cinnamal), or weak sensitizer (eugenol). Stimulation index (SI) and EC3 values were calculated for each agent. Based on the results of ex vivo LLNA-BrdU assays, EC3 values were calculated to be 0.29, 0.09, 1.91, and 16.60% for formaldehyde, PPD, cinnamal, and eugenol, respectively. These results were in good agreement with data from previous standard radioactive LLNA. Cytokine analyses indicated T(H)1 and T(H)2 cytokine involvement in the regulation of murine contact allergy and these could be utilized as endpoints in assessments of contact allergy in mice. In conclusion, the current study provided evidence that the non-radioactive endpoint LLNA BrdU ex vivo incorporation could be of use as a viable alternative approach to assess the skin sensitization potential of test compound with respect to improving animal welfare. This is of particular importance in the case of any laboratory where it might be difficult to handle and/or readily employ radioisotopes. Further studies will be required to confirm--across test agents--the reproducibility as well as the limits of utility of this new ex vivo BrdU method.

Evaluation of auricular lymph node cell lymphocyte proliferation and cytokine production as non-radioactive endpoints during murine contact allergy.

The murine local lymph node assay (LLNA) has been developed as a test method to assess allergic contact dermatitis. In spite of the validity of the LLNA, attention was drawn to the two disadvantages: use of radioactivity for in vivo measurement of lymph node cell proliferation ([(3)H]-thymidine labeling) and the possibility of false positive results caused by non-specific cell activation as a result of inflammatory processes in the skin (irritation). We aimed to investigate the following non-radioactive endpoints of LLNA: 5-bromo-2'-deoxyuridine (BrdU) incorporation ex vivo and in vivo, in vivo and ex vivo cytokine production with or without phytohemagglutinin (PHA) stimulation. Here, 8-12-week-old female BALB/c mice were treated topically with the strong sensitizer 2,4-dinitrochlorobenzene (DNCB) in acetone:olive oil (AOO, 4:1 [v/v]) at levels of 0.025, 0.05, 0.01, or 0.25% (w/v). Ear thickness was also measured to determine the differentiation index (DI) indicating the proportion of non-specific activation due to irritating properties of test compound. At the concentration of 0.05%, stimulation index (SI) value was found to be 3 for DNCB based on in vivo and ex vivo BrdU incorporation. The results of the in vivo and ex vivo non-radioactive LLNA assays were compatible both with each other and with previous radioactive LLNA data. Our results indicate that non-radioactive endpoints may be used as an alternative to the [(3)H]-thymidine LLNA. The levels of T(H)1 cytokines (IL-2 and IFNγ) and T(H)2 cytokines (IL-4 and IL-5) in lymph node cell cultures were significantly (P < 0.01) increased when DNCB was applied at the concentrations of 0.05 and 0.1%, respectively. As the DI was > 1, the applied concentrations of DNCB caused only allergic effect but not any irritant effect. This study reports that the use of these non-radioactive endpoints can assess allergic contact dermatitis caused by chemicals.

Estimation of ochratoxin A in some Turkish populations: an analysis in urine as a simple, sensitive and reliable biomarker.

In this study, ochratoxin A (OTA) occurrence and level in human urine samples, collected from four different regions of Turkey was analyzed by NaHCO(3) dilution, immunoaffinity column clean-up and high-performance liquid chromatography with fluorescent detection. For the repeatability of the method, RSD (%) values were found between 3.83 and 8.86, for the accuracy, the recovery values were found between 85.7% and 110.5% and limit of detection and limit of quantification of the method were measured as 0.006 and 0.018 ng mL(-1) respectively. For the analysis, first morning urine samples were collected and the results were adjusted with creatinine levels. From the total collected samples of 233 larger amounts of 83% was contaminated with OTA. Among the calculated to be OTA levels, positive sample rate, average OTA amount and the highest contamination was found in Ankara. (Positive sample rate; 90.1%, average OTA concentration; 14.34 ng g(-1) creatinine and highest OTA value; 75.60 ng g(-1) creatinine). In order to define the exposure profile of OTA in human a questionnaire was conducted among the voluntaries as well. But related to the gender, age, dietary habits, coffee consumption, smoking and alcohol habits of the volunteers, no correlation was found with the OTA exposure.