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Electron spin resonance of skin
Published in Roger L. McMullen, Antioxidants and the Skin, 2018
ESR imaging (also referred to as EPR imaging) allows for measurement of the spatial distribution of radicals in skin samples. In the early 1990s, there was a lot of interest in this topic among dermatological researchers working with ESR technology. Early studies by Kristel et al. demonstrated the utility of ESR imaging to monitor the distribution of exogenous nitroxides and nitroxide-labeled drugs in skin biopsies.57 Soon afterwards, a significant amount of work was completed by J. Fuchs et al. throughout the 1990s and into the twenty-first century, which brought ESR imaging of skin to its current state of development.1,6,23,58–63
The Spin Trapping of Superoxide Radicals
Published in Robert A. Greenwald, CRC Handbook of Methods for Oxygen Radical Research, 2018
Paul J. Thornalley, Joe V. Bannister
The technique of spin trapping was developed following research into nitroso/nitrone/ nitroxide group chemistry. It was first called spin trapping by Janzen and Blackburn.1 A detailed review of the development of the technique has been given by Perkins.2 The main disadvantages of using this technique for O2− detection are (1) most superoxide spin adducts are relatively unstable and decay rapidly to nonradical species and (2) the rate constants for the spin trapping of O2− are usually low (kT ≈ 10 M−1sec−1). A high concentration (60 to 200 mM) of spin trap is used to allow effective competition with spontaneous O2− dismutation.
Normal Tissue Tolerance
Published in Loredana G. Marcu, Iuliana Toma-Dasu, Alexandru Dasu, Claes Mercke, Radiotherapy and Clinical Radiobiology of Head and Neck Cancer, 2018
Loredana G. Marcu, Iuliana Toma-Dasu, Alexandru Dasu, Claes Mercke
Nitroxide compounds have been investigated as possible radioprotectors over the last couple of decades, due to their ability to alter the tissue’s redox status and to modify oxidative stress (Soule 2007). It was shown that both nitroxides radical and hydroxylamines (the reduction products), are recycling antioxidants that protect the cell against the oxidative stress, including the highly damaging hydrogen peroxide (Soule et al. 2007). The most representative nitroxide compound to date is tempol (4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl), which has been investigated in preclinical settings. In vivo animal studies showed that tempol was effectively protecting the salivary glands, without influencing tumour control (Cotrim et al. 2007), thus demonstrating a differential protection of normal tissues as compared to tumour cells.
Tempol modulates the leukocyte response to inflammatory stimuli and attenuates endotoxin-induced sickness behaviour in mice
Published in Archives of Physiology and Biochemistry, 2020
Samuel Nuno Pereira Lima, Cláudio Daniel Cerdeira, Gérsika Bitencourt Santos, Mateus de Mello Fernandes, Alexandre Giusti-Paiva, Maísa Ribeiro Pereira Lima Brigagão
In the present study, we tested the effects of Tempol on multiple key effectors and outcomes of inflammation. The positive effects of this nitroxide in an experimental mouse model were demonstrated. The discovery and development of new compounds with anti-inflammatory activity, has received a new impetus due to an increase in both population life expectancy and inflammatory disease incidence, which was followed by questions related to the safety of current anti-inflammatory drugs (Bidaut-Russell and Gabriel 2001, Vardeny and Solomon 2008). Traditionally, cyclooxygenase inhibitors are the most studied compounds able to act on a specific metabolic pathway active during inflammation, but this does not exclude the likelihood that new cellular targets, such as ROS production and other cellular signalling pathways, could be used for this purpose (Mitchell et al. 1991, Simmons 2006).
Development and characterization of a novel conductive polyaniline-g-polystyrene/Fe3O4 nanocomposite for the treatment of cancer
Published in Artificial Cells, Nanomedicine, and Biotechnology, 2019
Lida Ahmadkhani, Ebrahim Mostafavi, Samaneh Ghasemali, Roghayeh Baghban, Hamidreza Pazoki-Toroudi, Soodabeh Davaran, Javad Malakootikhah, Nahideh Asadi, Lala Mammadova, Siamak Saghfi, Thomas J. Webster, Abolfazl Akbarzadeh
First, the nitroxide group is produced on polystyrene backbone using strong nitric acid and sulphuric acid. In a round-bottomed flask containing strong nitric acid(15 ml), which was placed in the ice-water bath, the polystyrene coated iron oxide nanoparticles (Fe3O4/PS) (0.75 gr) was suspended in it. Then, 23 ml of strong sulphuric acid was slowly added to it and the temperature was enhanced to 30 °C and continued for 10 h. After the desired time, the product was filtered and washed with sufficiently of water. It was transferred to a Soxhlet’s extraction apparatus for reflux-extraction in 96% ethanol for 10 h. The product was dried under vacuum at 50 °C over 48 h. The product obtained in this step was Fe3O4/PS-NO2 (Scheme 3).
Application of hyaluronic acid as carriers in drug delivery
Published in Drug Delivery, 2018
Gangliang Huang, Hualiang Huang
In view of the specific binding of hyaluronic acid to the receptors on the surface of cancer cells, its biodegradability and biocompatibility, the application of hyaluronic acid in the targeted drug delivery of anticancer drugs has made great progress. It can be used as a carrier and react with other drugs to form conjugates. The conjugates have the controlled release and targeted effect, which can target the delivery of multiple drugs to various pathological sites, so as to achieve the purpose of timing and directional release (Chen et al., 2014). However, hyaluronic acid is easily degraded in the human body (Bot et al., 2008). Therefore, a nitroxide-containing substance should be added to protect the hyaluronic acid from being degraded or a hyaluronidase inhibitor is added to prevent degradation of hyaluronic acid by inhibiting the activity of hyaluronidase (Sung et al., 2014).