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There can be significant variability between bioreactivity studies of nanomaterials that are apparently the same, possibly reflecting differences in the models used and differing sources of experimental material. In this study, we have generated two crystal forms of titanium dioxide nanoparticles (nano-TiO2), pure anatase and pure rutile to address the hypothesis that the bioreactivity of these nanoparticles with human alveolar epithelium will depend on their crystal phase. We used a human alveolar type-I-like epithelial cell model (TT1; generated in-house from primary human alveolar epithelial type II cells); these cells cover 95% of the alveolar epithelial surface area and are an important target cell for inhaled nanomaterials. Using literature as a guide, we hypothesised that pure anatase nano-TiO2would display greater bioreactivity with TT1 cells in comparison to pure rutile nano-TiO2. However, we found the profile and pattern of inflammatory mediator release was similar between these two nano-TiO2formats, although pure rutile treatment caused a small, but consistently greater, response for IL-6, IL-8 and MCP-1. Interestingly, the temporal induction of oxidative stress (increased reactive oxygen species levels and depleted glutathione) varied markedly between the different nano-TiO2formats. We have shown that a combination of using nanomaterials synthesised specifically for toxicological study and the use of a highly relevant, reproducible human lung cell model, offers a useful approach to delineating the physicochemical properties of nanomaterials that may be important in their cellular reactivity. [ABSTRACT FROM PUBLISHER]

The respiratory epithelium is a significant target of inhaled, nano-sized particles, the biological reactivity of which will depend on its physicochemical properties. Surface-modified, 50 and 100 nm, polystyrene latex nanoparticles (NPs) were used as model particles to examine the effect of particle size and surface chemistry on transformed human alveolar epithelial type 1-like cells (TT1). Live images of TT1 exposed to amine-modified NPs taken by hopping probe ion conductance microscopy revealed severe damage and holes on cell membranes that were not observed with other types of NPs. This paralleled induction of cell detachment, cytotoxicity and apoptotic (caspase-3/7 and caspase-9) cell death, and increased release of CXCL8 (IL-8). In contrast, unmodified, carboxyl-modified 50 nm NPs and the 100 nm NPs did not cause membrane damage, and were less reactive. Thus, the susceptibility and membrane damage to respiratory epithelium following inhalation of NPs will depend on both surface chemistry (e.g., cationic) and nano-size. [ABSTRACT FROM AUTHOR]

The in vitro venom neutralizing capacity of tannic acid against the activities of Naja kaouthia (Naja naja kaouthia Lesson [Elapidae]) venom was investigated. Tannic acid was found to be effective in neutralizing the activities of Naja kaouthia (NK) venom. The lethal effect of four-times the LD50 in mice and the necrotizing effect of one minimum necrotizing dose (1 MND) in rats of NK venom were fully inhibited by tannic acid at ≥ 431 µg/mouse, with the median effective dose (ED50) of 334 µg/mouse and ≥ 30 µg/rat, respectively. The acetylcholinesterase activity of NK venom was almost completely neutralized (≥ 99%) by tannic acid at ≥ 1% w/v. It was evident that tannic acid was nontoxic and did not cause either a lethal effect in mice (at its maximum tested dose of 845 µg/mouse) or necrotic lesions in rats (at doses between 7.5 and 60 µg/rat). [ABSTRACT FROM AUTHOR]

Silver nanoparticles (AgNP) are known to penetrate into the brain and cause neuronal death. However, there is a paucity in studies examining the effect of AgNP on the resident immune cells of the brain, microglia. Given microglia are implicated in neurodegenerative disorders such as Parkinson's disease (PD), it is important to examine how AgNPs affect microglial inflammation to fully assess AgNP neurotoxicity. In addition, understanding AgNP processing by microglia will allow better prediction of their long term bioreactivity. In the present study, the in vitro uptake and intracellular transformation of citrate-capped AgNPs by microglia, as well as their effects on microglial inflammation and related neurotoxicity were examined. Analytical microscopy demonstrated internalization and dissolution of AgNPs within microglia and formation of non-reactive silver sulphide (Ag2S) on the surface of AgNPs. Furthermore, AgNP-treatment up-regulated microglial expression of the hydrogen sulphide (H2S)-synthesizing enzyme cystathionine-γ-lyase (CSE). In addition, AgNPs showed significant anti-inflammatory effects, reducing lipopolysaccharide (LPS)-stimulated ROS, nitric oxide and TNFα production, which translated into reduced microglial toxicity towards dopaminergic neurons. Hence, the present results indicate that intracellular Ag2S formation, resulting from CSE-mediated H2S production in microglia, sequesters Ag+ ions released from AgNPs, significantly limiting their toxicity, concomitantly reducing microglial inflammation and related neurotoxicity. [ABSTRACT FROM AUTHOR]

A topical antimicrobial ointment was developed from the fruit extract of Oroxylum indicum and was evaluated for its antibacterial and wound-healing effects and acute toxicity in animal models. O. indicum fruit and seed extracts exhibited antibacterial activities against clinically isolated bacteria and showed in vitro antioxidant activities. To develop a topical antimicrobial ointment from the fruit extract of O. indicum and evaluate for its antibacterial and wound-healing effects. O. indicum fruit extract ointment was prepared and qualitatively controlled. Acute toxicity of the extract was evaluated in the animal model. Antibacterial effects and healing effects of the ointment to the dog wound were investigated. The results are expressed as mean ± standard deviation. The ointment exhibited in vitro antibacterial effects. A single daily application of the ointment to a dog's wound exhibited a wound-healing effect with complete epithelialization within 7 days while the wound was completely healed with the removal of the scabs, the size was decreased to 14% of the original size within 12 days. The ointment was found no acute toxicity in the animal model. O. indicum ointment promoted in vitro antibacterial activity and wound-healing effect in dogs with no acute toxicity., Competing Interests: There are no conflicts of interest., (Copyright: © 2024 Journal of Advanced Pharmaceutical Technology & Research.)