Correlation of molecular total surface area with organotin toxicity for biological and physicochemical applications

There exists a high correlation between molecular total surface area (TSA) values and diorganotin toxicity towards several distinct types of organisms. This correlation was found for N₂a neuroblastoma cells, 3T3 fibroblasts, Daphnia magna Rhithropanopeus harrisii and Ankistrodesmus falcatus. In the case of Rhithropanopeus harrisii, a high correlation was also found between TSA and toxicity for triorganotins as well. This study suggests that the relationship between TSA and toxicity is a function of the hydrophobicity of the organotin compounds rather than electronic or steric effects.     

The effects of organolead compounds on a freshwater and a marine alga

There are conflicting reports concerning the toxicity of tetraalkyllead (TAL) compounds to algae. A number of groups have found the TAL's to be comparable in toxicity with the trialkyllead compounds (R₃Pb⁺), whereas in a recent report it is suggested that the TAL's themselves are completely non-toxic and any apparent toxicity is due to R₃Pb⁺ breakdown products. With the object of identifying the toxic agent, the effect of Et₄Pb (TEL) on two algal species was re-examined. Analyses were carried out during the course of the incubations to establish the nature and concentrations of organoleads present in both media and algae, and hence evaluate their relative contributions to total toxicity. Algae were also cultured in the presence of Me₄Pb (TML), Me₃PbCl, Et₃PbCl, Bu₃PbCl and Et₂PbCl₂ to assess relationships between alkyl chain length and degree of substitution around the lead on algal activity. Additions of selenide and sulphide were made to the Et₃Pb⁺ and Et₂Pb²⁺ systems to see if these environmentally abundant species reduced or enhanced organolead toxicity. Problems were encountered in the analysis of the heterogeneous TEL containing media. Regardless of the analytical problems, the results confirm the previous findings that TAL's are non-toxic to algae and it is the R₃Pb⁺ breakdown products which are responsible for the apparent toxicity of the TAL's. The trialkylleads were the most toxic of the several alkyllead species studied, and within the trialkyl series toxicity increased with alkyl chain length. Neither selenide or sulphide had any significant ameliorative effect on alkyllead toxicity. It was found that the ionic organoleads were complexed on the TAL's and this complexing led to a number of unexpected results.     

Luminescence investigations of the degradation of 2-methylphenol and 4-methylphenol in water

Fluorescent characteristics of the photo- and biotransformations of 2-methylphenol, 4-methylphenol and their mixtures in water exposed to uv radiation of various sources and to Penicillium tardum H-2 culture have been studied. The toxicity of these solutions has also been investigated by means of bioluminescent testing. Preliminary exposure of a 4-methylphenol solution (10⁻³ M) to uv radiation with λ ∼ 308 nm or to the radiation of a mercury lamp inhibited the subsequent microbiological degradation. Efficient decomposition of methylphenol molecules in the mixture was detected when it was exposed to the radiation of a mercury lamp or to 222-nm radiation and then subject to biodecomposition. The irradiation of solutions of 2-methylphenol and 4-methylphenol and their low-concentration mixtures with 308-nm uv radiation or with the radiation of a mercury lamp resulted in detoxication of the solutions. Extreme toxicity was shown by 4-methylphenol solutions on exposure to uv radiation with λ ∼ 222 nm. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 12, pp. 88–98, December, 2008.     

Acute toxicological impact of nano- and submicro-scaled zinc oxide powder on healthy adult mice

In this work, the acute oral toxicity of 20- and 120-nm ZnO powder at doses of 1-, 2-, 3-, 4-, 5-g/kg body weight was evaluated referred to the OECD guidelines for testing of chemicals. As the results, both 20- and 120-nm ZnO belong to non-toxic chemicals according to the Globally Harmonized Classification System (GHS) for the classification of chemicals. The distribution determination showed that Zn was mainly retained in the bone, kidney and pancreas after 20- and 120-nm ZnO administration. However, the results of blood measurement suggest that the increase in blood viscosity could be induced by low and median dose of 20-nm ZnO but high dose of 120-nm ZnO. The pathological examination showed that the 120-nm ZnO treated mice had dose–effect pathological damages in stomach, liver, heart and spleen, whereas, 20-nm ZnO displayed negative dose–effect damages in liver, spleen and pancreas. Therefore, we conclude that the liver, spleen, heart, pancreas and bone are the target organs for 20- and 120-nm ZnO oral exposure. More attention should be paid on the potential toxicity induced by low dose of 20-nm ZnO oral exposure.     

Anaerobic toxicity and biodegradability of hydrolysis products of chemical warfare agents

The toxicity and biodegradability of the main hydrolysis products of chemical warfare agents were investigated under methanogenic conditions. Among the tested substances, only MPhA does not have any toxic effect with regard to the aceticlastic methanogenic activity. The toxicity of other compounds varied between moderate (TDG, mercaptoethanol) to strong (ethanolamine, diisobutyl ester of MPhA). Biodegradability tests showed that all the products of chemical detoxification of mustard gas (ethanolamine, ethylene glycol, TDG, mercaptoethanol) can be biomineralized under methanogenic conditions. On the contrary, phosphorus-containing compounds from the chemical detoxification of nerve warfare agents (Sarin, Soman, V_x-gases) are quite persistent under these conditions.     

Acetylharpagide Protects Mice from Staphylococcus Aureus-Induced Acute Lung Injury by Inhibiting NF-κB Signaling Pathway

Staphylococcus aureus (S. aureus)-induced acute lung injury (ALI) is a serious disease that has a high risk of death among infants and teenagers. Acetylharpagide, a natural compound of Ajuga decumbens Thunb. (family Labiatae), has been found to have anti-tumor, anti-inflammatory and anti-viral effects. This study investigates the therapeutic effects of acetylharpagide on S. aureus-induced ALI in mice. Here, we found that acetylharpagide alleviated S. aureus-induced lung pathological morphology damage, protected the pulmonary blood-gas barrier and improved the survival of S. aureus-infected mice. Furthermore, S. aureus-induced myeloperoxidase (MPO) activity of lung homogenate and pro-inflammatory factors in bronchoalveolar lavage (BAL) fluid were suppressed by acetylharpagide. Mechanically, acetylharpagide inhibited the interaction between polyubiquitinated receptor interacting protein 1 (RIP1) and NF-κB essential modulator (NEMO), thereby suppressing NF-κB activity. In summary, these results show that acetylharpagide protects mice from S. aureus-induced ALI by suppressing the NF-κB signaling pathway. Acetylharpagide is expected to become a potential treatment for S. aureus-induced ALI.     

Methiocarb Degradation by Electro-Fenton: Ecotoxicological Evaluation

This paper studies the degradation of methiocarb, a highly hazardous pesticide found in waters and wastewaters, through an electro-Fenton process, using a boron-doped diamond anode and a carbon felt cathode; and evaluates its potential to reduce toxicity towards the model organism Daphnia magna. The influence of applied current density and type and concentration of added iron source, Fe₂(SO₄)₃·5H₂O or FeCl₃·6H₂O, is assessed in the degradation experiments of methiocarb aqueous solutions. The experimental results show that electro-Fenton can be successfully used to degrade methiocarb and to reduce its high toxicity towards D. magna. Total methiocarb removal is achieved at the applied electric charge of 90 C, and a 450× reduction in the acute toxicity towards D. magna, on average, from approximately 900 toxic units to 2 toxic units, is observed at the end of the experiments. No significant differences are found between the two iron sources studied. At the lowest applied anodic current density, 12.5 A m⁻², an increase in iron concentration led to lower methiocarb removal rates, but the opposite is found at the highest applied current densities. The highest organic carbon removal is obtained at the lowest applied current density and added iron concentration.     

Toxicological Screening of Four Bioactive Citroflavonoids: In Vitro,In Vivo,and In Silico Approaches

Many studies describe different pharmacological effects of flavonoids on experimental animals and humans. Nevertheless, few ones are confirming the safety of these compounds for therapeutic purposes. This study aimed to investigate the preclinical safety of naringenin, naringin, hesperidin, and quercetin by in vivo, in vitro, and in silico approaches. For this, an MTT-based cytotoxicity assay in VERO and MDCK cell lines was performed. In addition, acute toxicity was evaluated on Wistar rats by OECD Guidelines for the Testing of Chemicals (Test No. 423: Acute Oral Toxicity-Class Method). Furthermore, we used the ACD/Tox Suite to predict toxicological parameters such as hERG channel blockade, CYP450 inhibition, and acute toxicity in animals. The results showed that quercetin was slightly more cytotoxic on cell lines (IC₅₀ of 219.44 ± 7.22 mM and 465.41 ± 7.44 mM, respectively) than the other citroflavonoids. All flavonoids exhibited an LD₅₀ value > 2000 mg/kg, which classifies them as low-risk substances as OECD guidelines established. Similarly, predicted LD⁵⁰ was LD₅₀ > 300 to 2000 mg/kg for all flavonoids as acute toxicity assay estimated. Data suggests that all these flavonoids did not show significant toxicological effects, and they were classified as low-risk, useful substances for drug development.     

The Effect of Polymer Dots During Mammalian Early Embryo Development and Their Biocompatibility on Maternal Health

Conjugated polymer dots have excellent fluorescence properties in terms of their structural diversity and functional design, showing broad application prospects in the fields of biological imaging and biosensing. Polymer dots contain no heavy metals and are thought to be of low toxicity and good biocompatibility. Therefore, systematic studies on their potential toxicity are needed. Herein, the biocompatibility of poly[(9,9‐dioctylfluorenyl‐2,7diyl)‐co‐(1,4‐benzo‐{2,1′,3}‐thiadiazole)],10% benzothiadiazole(y) (PFBT) and poly[2‐methoxy‐5‐(2‐ethylhexyloxy)‐1,4‐phenylenevinylene] (MEH‐PPV) polymer dots on early embryo development as well as maternal health is studied in detail. The results show that prepared polymer dots are dose‐dependently toxic to preimplantation embryos, and low‐dose polymer dots can be used for cell labeling of early embryos without affecting the normal development of embryos into blastocysts. In addition, the in vivo distribution data show that the polymer dots accumulate mainly in the maternal liver, spleen, kidney, placenta, ovary, and lymph nodes of the pregnant mice. Histopathological examination and blood biochemical tests demonstrate that exposure of the maternal body to polymer dots at a dosage of 14 µg g^?1 does not affect the normal function of the maternal organs and early fetal development. The research provides a safe basis for the wide application of polymer dots.