Tomoko Komatsu

Direct Assessments of the Antioxidant Effects of Propofol Medium Chain Triglyceride/Long Chain Triglyceride on the Brain of Stroke-prone Spontaneously Hypertensive Rats Using Electron Spin Resonance Spectroscopy

Background:Antioxidant anesthetics such as propofol (2,6-diisopropylphenol) directly inhibit lipid peroxidation via the generation of reactive oxygen species. Currently, there are no other studies regarding the direct effects of propofol medium chain triglyceride/long chain triglyceride (MCT/LCT) on reactive oxygen species generation or in experimental models of reactive oxygen species–induced oxidative stress in the brain. Methods:The authors investigated the effects of propofol MCT/LCT on reactive oxygen species (hydroxyl radical or superoxide) by electron spin resonance spin trapping with 5,5-dimethyl-1-pyrroline-N-oxide. The effects of propofol MCT/LCT on oxidative stress in the brain of Wistar-Kyoto rats or stroke-prone spontaneously hypertensive rats were investigated by using an in vivo L-band electron spin resonance system to monitor the decay rate of 3-methoxycarbonyl-2,2,5,5-tetramethyl-pyrrolidine-1-oxyl as a nitroxyl spin probe. Results:These studies provided direct evidence that propofol MCT/LCT inhibited hydroxyl radical generation, but not superoxide generation. Regarding the hydroxyl radical from the Fenton system, it is likely to be due to the scavenging effects of vehicle. Anesthesia with propofol MCT/LCT reduced the degree of the high oxidative stress in the brain of stroke-prone spontaneously hypertensive rats. Conclusion:The current data show that propofol, mixed with clinical reagents (propofol MCT/LCT), resulted in the down-regulation of high oxidative stress due to scavenging hydroxyl radical, as demonstrated by in vitro or in vivo electron spin resonance analysis. These results led to reduced levels of hydroxyl radical, formed by brain injury such as stroke, and may therefore provide advantages for neuroprotection during anesthesia for craniotomy, e.g., in cases of brain disease.

Inhibition of superoxide generation from fMLP-stimulated leukocytes by high concentrations of nitric oxide or peroxynitrite: characterization by electron spin resonance spectroscopy

Abstract A Corrigendum has been published for this article in Redox Report, Volume 17, Number 1, January 2012, page 47: http://www.ingentaconnect.com/content/maney/rer/2012/00000017/00000001/art00006 (please copy and paste this URL into your web browser in order to link to it)This present study examined the effects of high concentrations of nitric oxide (NO•) and peroxynitrite (ONOO-) on superoxide (O2•-) production from formyl-methionyl-leucyl-phenylalanine (fMLP)-stimulated polymorphonuclear leukocytes (PMNs) by using electron spin resonance (ESR) and spin trapping with 5-(diethoxyphosphoryl)-5-methyl-1-pyrroline-N-oxide (DEPMPO). We demonstrated that ONOO- (100 μM) decreased the ESR signal of DEPMPO-OOH from fMLP-activated PMNs, indicating the inhibition of O2•- generation, while it enhanced the signal of DEPMPO-OH. Inhibition of the respiratory burst was also observed when PMNs were pre-exposed to high concentrations of NO• (100 μM), generated by the NO• donor NOR-1, 30 min prior to stimulation with fMLP. NOR-1 inhibited O2•- generation more effectively under conditions in which ONOO- was formed concurrently. The ability of high concentrations of either ONOO- or NO• to inhibit O2•- generation from fMLP-stimulated PMNs is relevant to pathophysiological conditions, such as severe inflammation, in which NO• or ONOO- production can be significantly elevated.

Reactive oxygen species generation in gingival fibroblasts of Down syndrome patients detected by electron spin resonance spectroscopy.

Abstract Oral manifestations of Down syndrome include high susceptibility to gingival inflammation with early onset and rapidly progressive periodontitis. The influence of reactive oxygen species (ROS) on periodontitis of Down syndrome is unclear. The aim of this study was to characterize ROS formation in Down syndrome-gingival fibroblasts (DS-GF) using electron spin resonance (ESR) spin trapping with 5,5-dimetyl-1-pyrolline-N-oxide (DMPO), and to determine whether ROS generation plays a role in the pathogenesis of periodontitis in Down syndrome patients. We observed formation of the DMPO-OH spin adduct, indicating HO• generation from cultured DS-GF and non-DS-GF. The increased HO• generation in cultured DS-GF was strongly decreased in the presence of the H2O2 scavenger, catalase, or the iron chelator, desferal. This may due to the enzymatic ability of over-expressed CuZn-superoxide dismutase in Down syndrome to catalyze the formation of H2O2 from O2•−, thereby increasing the availability of substrate H2O2 for the irondependent generation of HO• via the Fenton reaction, suggesting that HO• generated from DS-GF may be involved in progressive periodontitis of Down syndrome.

Assessments of salivary antioxidant activity using electron spin resonance spectroscopy.

OBJECTIVE In recent years, the function of saliva has been focused on evaluation of general status. The relationship between salivary antioxidant activity and periodontal disease progression is unclear. The aim of this study is to assess the relationship between periodontal disease and salivary antioxidant activity towards various reactive oxygen species (ROS) using electron spin resonance (ESR) technique. METHODS We demonstrated that whole saliva derived rats or human subjects scavenged ROS such as superoxide (O(2)(·-)) and hydroxyl radical (HO(·)) using ESR spectroscopy with spin trapping agent. In addition, we assessed the relationship between antioxidants activity towards ROS and periodontal index with superoxide dismutase (SOD) activity in human subject saliva. RESULTS Antioxidant activity towards O(2)(·-) was increased by Porphyromonas gingivalis (P. gingivalis) infection in rat, although antioxidant activity towards HO(·) was not changed. In human, a strong correlation (r = 0.88, p < 0.01) recognized between salivary antioxidant activity towards O(2)(·-) and probing pocket depth (PPD). In addition, the intensity of salivary antioxidant activity depended on SOD activity level. SOD activity was also correlated with PPD. CONCLUSIONS Rat salivary antioxidant activity towards O(2)(·-) was up-regulated by the inflammatory response caused by P. gingivalis infection. Similar response was recognized in human saliva with periodontal index. Additionally, a linear correlation between antioxidant activity towards O(2)(·-) and SOD activity was verified by ESR technique. Therefore, evaluation of the salivary antioxidant activity towards O(2)(·-) might be an effective parameter for the objective assessment of periodontal disease progression.

Medical-grade collagen peptide in injectables provides antioxidant protection

Abstract Medical-grade collagen peptide is used as an additive agent in pharmaceutical formulations; however, it is unknown as to whether the compound exerts antioxidant effects in vitro. In this study, we evaluated the antioxidant effects of medical-grade collagen peptide on reactive oxygen species such as hydroxyl radical, superoxide anion radical and singlet oxygen using electron spin resonance and spin trapping. We confirmed that medical-grade collagen peptide directly inhibited hydroxyl radical generated by the Fenton reaction or by ultraviolet irradiation of hydrogen peroxide, and singlet oxygen. In addition, an antioxidant effect of medical-grade collagen peptide on singlet oxygen was observed in peptide fractions 12–22. The total amount of antioxidant amino acids (Gly, Hyp, Glu, Ala, Cys, Met and His) constituted more than half of the total amino acids in these fractions. These results suggest that the observed antioxidant properties of medical-grade collagen peptide are due to the compound containing antioxidant amino acids. Medical-grade collagen peptide, which is used in pharmaceuticals, and especially in injectables, could provide useful antioxidant properties to protect the active ingredient from oxidation.

Oxidative Stress and Periodontal Disease in Down Syndrome

Down syndrome (DS) is caused by a unique metabolic imbalance induced by overexpression of genes on chromosome 21. The enzyme superoxide dismutase (SOD) is responsible for the regulation of reactive oxygen species (ROS) homeostasis. Increased levels or activity of SOD may contribute to neuronal death and disease progression in DS and precede the signature manifestations of the disease by decades. Individuals with DS have a higher prevalence and severity of periodontal disease, which cannot be explained by poor oral hygiene alone and is related to changes in the immune response. Using electron spin resonance (ESR) and spin trapping, we have obtained clear and direct evidence that ROS are generated in the media of cultured gingival cells from DS patients.

Oral characteristics of a patient with Ekman-Westborg-Julin trait: a case history.

This article presents the case of a Japanese woman who had Ekman-Westborg-Julin trait. She had general macrodontia with multituberculism, evagination of the premolar, single conical roots, shovel-shaped incisors, enamel hypoplasia, impacted tooth, dental crowding, and an open bite. The oral and general characteristics of this patient are described and include the histological and radiographic findings of the mandibular third molars. We suggest that the distinctive oral features with macrodontia of the permanent teeth, multituberculism, evagination, single conical roots, and impaction of the tooth could be defined as the Ekman-Westborg-Julin trait.