Selective Oxidation of Transient Organic Radicals in the Presence of Gold Nanoparticles

The ability of gold nanoparticles (AuNPs) to catalyze reactions involving radicals is poorly studied. However, AuNPs are used in applications where chemical reactions involving transient radicals occur. Herein, we investigate AuNPs’ catalytic effect on 2-propanol oxidation and acetanilide hydroxylation in aqueous solutions under ionizing radiation at room temperature. In both cases, the presence of AuNPs led to selective oxidation of organic radicals, significantly changing the products’ composition and ratio. Based on these observations, we stress how AuNPs’ catalytic activity can affect the correctness of reactive oxygen species concentration determination utilizing organic dyes. We also provide a discussion on the role of AuNPs’ catalytic activity in the radiosensitization effect actively studied for radiotherapy.

Antibiofilm and Antioxidant Activity of Propolis and Bud Poplar Resins versusPseudomonas aeruginosa

Pseudomonas aeruginosais a common biofilm-forming bacterial pathogen implicated in lung, skin, and systemic infections. Biofilms are majorly associated with chronic lung infection, which is the most severe complication in cystic fibrosis patients characterized by drug-resistant biofilms in the bronchial mucus with zones, where reactive oxygen species concentration is increased mainly due to neutrophil activity. Aim of this work is to verify the anti-Pseudomonasproperty of propolis or bud poplar resins extracts. The antimicrobial activity of propolis and bud poplar resins extracts was determined by MIC and biofilm quantification. Moreover, we tested the antioxidant activity by DPPH and neutrophil oxidative burst assays. In the end, both propolis and bud poplar resins extracts were able to inhibitP. aeruginosabiofilm formation and to influence both swimming and swarming motility. Moreover, the extracts could inhibit proinflammatory cytokine production by human PBMC and showed both direct and indirect antioxidant activity. This work is the first to demonstrate that propolis and bud poplar resins extracts can influence biofilm formation ofP. aeruginosacontrasting the inflammation and the oxidation state typical of chronic infection suggesting that propolis or bud poplar resins can be used along with antibiotic as adjuvant in the therapy againstP. aeruginosainfections related to biofilm.

UV Photocatalysis of Bone Marrow-Derived Macrophages on TiO2Nanotubes Mediates Intracellular Ca2+Influx via Voltage-Gated Ca2+Channels

Titanium (Ti) possesses excellent properties for use in dental implants but has low osteogenic surface properties that result in limiting rapid osseointegration. The physiological interaction between the surface of the implant material and bone cells, especially osteoclasts, is a crucial factor in determining successful osseointegration. However, the details of such an interaction remain elusive. Here, we demonstrated that nanotopography on the Ti surface is a crucial factor for modulating intracellular signal transduction in bone marrow-derived macrophages (BMMs). To define this, intracellular Ca2+and ROS were simultaneously measured in BMMs that were seeded on polished Ti and TiO2nanotubes. We found that UV photocatalysis of TiO2immediately elicits intracellular calcium concentration ([Ca2+]i) increase and intracellular reactive oxygen species concentration ([ROS]i) reduction in cells on TiO2nanotubes. UV photocatalysis-mediated [Ca2+]iincrease is dependent on extracellular and intracellular ROS generation. Furthermore, extracellular Ca2+influx through voltage-gated calcium channels (VGCCs) is critical for the UV photocatalysis-mediated [Ca2+]iincrease, while phospholipase C (PLC) activation is not required. Considering the physiological roles of Ca2+signaling in BMMs and osteoclastogenesis, nanotopography on the Ti surface should be considered an important factor that can influence successful dental implantation.

Antioxidant effect of pomegranate extract in reducing acute inflammation due to myringotomy

Objective:To assess the effect of pomegranate extract on acute inflammation due to myringotomy.Design:Prospective, randomised study.Subjects:Thirty Sprague–Dawley rats were divided into three groups. Group one constituted controls. Group two underwent myringotomy. Group three underwent myringotomy and also received 100 µl/day pomegranate extract, via gavage, one day before and two days after surgery. Following sacrifice 48 hours after myringotomy, the animals' right ears were used to determine the concentration of reactive oxygen species, using the chemiluminescence method; left ears were used for histological study.Results:Reactive oxygen species levels were significantly decreased in group three compared with group two (p < 0.01). The density of inflammatory cells in group three was significantly less than that in group two (p < 0.01). Lamina propria thickness and vessel density were also significantly decreased in group three compared with group two (p < 0.01).Conclusion:Our results indicate that oral pomegranate extract decreases reactive oxygen species concentration and acute inflammation in the tympanic membrane after myringotomy.