The redox status of tumors inoculated into the footpads of mice was investigated by using an in vivo ESR/spin-probe technique. A single-cell suspension of a metastatic subclone of colon carcinoma NL-17 was inoculated into the footpads of Balb/c mice. At 12, 24, 48, and 96 h after the inoculation, a spin probe, either carbamoylor carboxy-PROXYL, was intravenously injected, and then the ESR spectra of each footpad were separately obtained under a one-dimensional magnetic-field gradient. The change in the ESR signal intensity of the spin probe was closely related to the tumor volume in the footpads, but no significant difference was observed between carbamoyl- and carboxy-PROXYL. The in vivo ESR signal decay of carbamoyl-PROXYL, which is related to the conversion of the nitroxyl radical to hydroxylamine, was enhanced in the inoculated footpads but not in the reference one. The ESR signal decay was not influenced by coadministration of radical scavengers, SOD, catalase, mannitol, or dimethylthiourea, suggesting that the redox status but not reactive oxygen species generation played a role in the enhanced signal decay.
Generation of hydroxyl radicals, one of the major active species in ozonation of water was directly observed with a spin-trapping/electron spin resonance (ESR) technique using 5,5-dimethyl-1-pyrrolineN-oxide (DMPO) as a spin-trapping reagent. Hydroxyl radical were trapped with DMPO as a stable radical, DMPO-OH. Eighty μM of ozone produced 1.08 X 10-6M of DMPO-OH, indicating that 1.4% of •OH is trapped with DMPO. Generation rate of DMPO-OH was determined by ESR/stopped-flow measurement. Phenol derivatives increased the amount and generation rate of DMPO-OH, indicating that phenol derivatives enhance •OH generation during ozonation of water. Ozonation of 2,3-, 2,5-, 2,6-dichlorophenol gave an ESR spectra of triplet lines whose peak height ratio were 1:2:1. ESR parameters of the triplet lines agreed with those of the corresponding dichloro-psemiquinone radical. Ozonation of 2,4,5- and 2,4,6-trichlorophenol gave the same spectra as those of 2,5- and 2,6-dichlorophenol, respectively, indicating that a chlorine group in p-position is substituted with a hydroxy group during ozonation. Amounts of the radical increased in an ozone-concentration dependent manner and were inhibited by addition of hydroxyl radical scavengers. These results suggest that p-semiquinone radicals are generated from the chlorophenols by hydroxyl radicals during ozonation. The p-semiquinone radicals were at least partly responsible for enhancements of DMPO-OH generation.
The interaction between Triton X-100 and phosphatidylcholine liposomes was studied by the spin labeling technique and turbidity measurement. The order parameter (S) of spin labeled stearic acid and the turbidity both decreased upon addition of Triton X-100. The effect of Triton X-100 depended on the species of phosphatidylcholine. In egg phosphatidylcholine liposomes, the effect of Triton X-100 was biphasic. In the range of low Triton/phospholipid molar ratios (below 0.4) there was a gradual decrease in the S value without any appreciable decrease in the turbidity. This suggests that Triton X-100 fluidizes the membrane without forming small fragments. Above a molar ratio of 0.4 there was a drastic decline in the turbidity, indicating that the membrane was solubilized. In dimyristoylphosphatidylcholine liposomes, biphasic behavior was not observed. The S value and the turbidity decreased noticeably upon addition of a little Triton X-100. The sensitivity of dimyristoylphosphatidylcholine liposomes to Triton X-100 was much greater than that of egg phosphatidylcholine liposomes. Phase separation between phosphatidylcholine-rich regions and Triton-rich regions may occur in view of the S values reached upon the addition of Triton X-100 to both phosphatidylcholine liposomes. This was also indicated by the spectral change of spin labeled phosphatidylcholine liposomes caused by Triton X-100.
To determine the genotoxicity of river water towards mammalian cells, we applied Micronucleus in vitro test using mammalian cells to the samples taken from river Tamagawa located between Tokyo and Kanagawa prefecture. Water samples were condensed by Sep-pak cartridges and extracted by dichloromethane and methanol. Positive genotoxicity was observed in methanol extracts from sampling stations of Hinobashi and Marukobashi, while no dichloromethane extracts showed genotoxicity, suggesting that polar genotoxic micropollutants may be contained in the water of Tamagawa, at least in its down-stream. Significantly high mutagenicity also detected from Hinobashi and Marukobashi by Ames mutagenicity test using Salmonella Typhimurium, and some difference was obtained in sensitivity between the two methods. This may arise from the difference in species used, that is, mammalian cells in micronucleus test and bacteria in Ames mutagenicity test.
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTInteraction of spin-labeled lysophosphatidylcholine with rabbit erythrocytesHideo Utsumi, Keizo Inoue, Shoshichi Nojima, and Takao KwanCite this: Biochemistry 1978, 17, 10, 1990–1996Publication Date (Print):May 16, 1978Publication History Published online1 May 2002Published inissue 16 May 1978https://pubs.acs.org/doi/10.1021/bi00603a030https://doi.org/10.1021/bi00603a030research-articleACS PublicationsRequest reuse permissionsArticle Views56Altmetric-Citations18LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts
Twelve high schools in Japan (of which six are in Fukushima Prefecture), four in France, eight in Poland and two in Belarus cooperated in the measurement and comparison of individual external doses in 2014. In total 216 high-school students and teachers participated in the study. Each participant wore an electronic personal dosimeter "D-shuttle" for two weeks, and kept a journal of his/her whereabouts and activities. The distributions of annual external doses estimated for each region overlap with each other, demonstrating that the personal external individual doses in locations where residence is currently allowed in Fukushima Prefecture and in Belarus are well within the range of estimated annual doses due to the background radiation level of other regions/countries.
Redox metabolism plays a central role in maintaining homeostasis in living organisms. The electron transfer system in mitochondria produces ATP via endogenous redox molecules such as flavin mononucleotide (FMN), flavin adenine dinucleotide (FAD), and coenzyme Q10 (CoQ10), which have flavin or quinone moieties. One-electron transfer reactions convert FMN, FAD, and CoQ10 to the free radical intermediates FMNH and FADH, and CoQ10H, respectively. Dynamic nuclear polarization-magnetic resonance imaging (DNP-MRI) allows us to visualize free radicals in vitro and in vivo. We present a spectroscopic imaging technology with DNP-MRI, which enables the imaging of multiple free radical intermediates such as FADH and CoQH. DNP-MRI can also identify various endogenous free radical intermediates derived from redox transformations.
Reactive Oxygen Species (ROS) may regulate signaling, ion channels, transcription factors, and biosynthetic processes. ROS-related diseases can be due to either a shortage or an excess of ROS.Since the biological activity of ROS depends on not only concentration but also spatiotemporal distribution, real-time imaging of ROS, possibly in vivo, has become a need for scientists, with potential for clinical translation. New imaging techniques as well as new contrast agents in clinically established modalities were developed in the previous decade.An ideal imaging technique should determine ROS changes with high spatio-temporal resolution, detect physiologically relevant variations in ROS concentration, and provide specificity toward different redox couples. Furthermore, for in vivo applications, bioavailability of sensors, tissue penetration, and a high signal-to-noise ratio are additional requirements to be satisfied.None of the presented techniques fulfill all requirements for clinical translation. The obvious way forward is to incorporate anatomical and functional imaging into a common hybrid-imaging platform. Antioxid. Redox Signal. 24, 939-958.
Amyloid nitroxyl radical (nitroxide) ligands were used to detect amyloid-β fibrils, the main constituents of senile plaques in Alzheimer's disease, using anisotropic ESR spectra, and were found to affect the aggregation process due to the radical functionality. These compounds have great potential as novel and multifunctional probes, combining spin labels, spin probes, and fluorescence probes.
