Pub Date : 2021-11-01DOI: 10.1136/bjsports-2021-ioc.37
Behnam Liaghat, J. Bencke, M. Zebis, H. Sørensen, G. Myklebust, N. Wedderkopp, Martin Lind, M. Møller
{"title":"039 Shoulder rotation strength changes from preseason to midseason: a cohort study of 292 youth elite handball players without shoulder problems","authors":"Behnam Liaghat, J. Bencke, M. Zebis, H. Sørensen, G. Myklebust, N. Wedderkopp, Martin Lind, M. Møller","doi":"10.1136/bjsports-2021-ioc.37","DOIUrl":"https://doi.org/10.1136/bjsports-2021-ioc.37","url":null,"abstract":"","PeriodicalId":12438,"journal":{"name":"Free radical research communications","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85745361","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1993-01-01DOI: 10.3109/10715769309056494
K Nagy, G Pásti, L Bene, I Zs-Nagy
Tumor cells usually contain lower superoxide dismutase (SOD) activity than differentiating cells, suggesting the involvement of oxygen free radicals in cell maturation. The effects of a system known to produce the OH. radicals were tested on HL-60 cells cultured under optimum conditions for 96 hr. Hydroxyl radicals were generated by a Fenton reaction, involving an ADP-Fe2+ (or ATP-Fe2+) complex and H2O2. Changes induced by OH. were compared to the effects of DMSO-induced differentiation of HL-60 cells. Cell numbers, viability, thymidine incorporation, TPA-induced NBT reduction and propidium iodide staining in flow cytometry were determined. The OH. generating system inhibited the growth and thymidine incorporation of leukemic cells in a manner dependent on the dose of added H2O2 (from 0.005 to 0.05 mM). In addition, an increasing proportion of the treated cells displayed signs of cell differentiation. In DMSO-treated cells, SOD and catalase activities increased after 6 days of culturing. The results show that a portion of the OH. free radicals derived from H2O2, produced by the action of SOD, may be a necessary prerequisite for differentiation, whereas an overproduction of OH. causes cell lethality or aging. We suggest that OH. free radicals may have a more complex role in cell physiology than simply causing oxidative damage.
{"title":"Induction of granulocytic maturation in HL-60 human leukemia cells by free radicals: a hypothesis of cell differentiation involving hydroxyl radicals.","authors":"K Nagy, G Pásti, L Bene, I Zs-Nagy","doi":"10.3109/10715769309056494","DOIUrl":"https://doi.org/10.3109/10715769309056494","url":null,"abstract":"<p><p>Tumor cells usually contain lower superoxide dismutase (SOD) activity than differentiating cells, suggesting the involvement of oxygen free radicals in cell maturation. The effects of a system known to produce the OH. radicals were tested on HL-60 cells cultured under optimum conditions for 96 hr. Hydroxyl radicals were generated by a Fenton reaction, involving an ADP-Fe2+ (or ATP-Fe2+) complex and H2O2. Changes induced by OH. were compared to the effects of DMSO-induced differentiation of HL-60 cells. Cell numbers, viability, thymidine incorporation, TPA-induced NBT reduction and propidium iodide staining in flow cytometry were determined. The OH. generating system inhibited the growth and thymidine incorporation of leukemic cells in a manner dependent on the dose of added H2O2 (from 0.005 to 0.05 mM). In addition, an increasing proportion of the treated cells displayed signs of cell differentiation. In DMSO-treated cells, SOD and catalase activities increased after 6 days of culturing. The results show that a portion of the OH. free radicals derived from H2O2, produced by the action of SOD, may be a necessary prerequisite for differentiation, whereas an overproduction of OH. causes cell lethality or aging. We suggest that OH. free radicals may have a more complex role in cell physiology than simply causing oxidative damage.</p>","PeriodicalId":12438,"journal":{"name":"Free radical research communications","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1993-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3109/10715769309056494","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"19214428","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1993-01-01DOI: 10.3109/10715769309056s71
J Taira, T Ikemoto, K Mimura, A Hagi, A Murakami, K Makino
In aqueous media, approximate rate constants for the reactions between hydroxyl radicals (.OH) and biphenyl compounds such as dehydrodieugenol, magnolol, honokiol, dehydrodidihydroeugenol, dehydrodivanillyl alcohol, and dehydrodicreosol were estimated by competition reactions for .OH between these biphenyls and 5,5-dimethyl-1-pyrroline-N-oxide (DMPO). By measuring the decrease in the height of the EPR signals of the .OH spin adduct, rate constants in the order of 10(9) to 10(10) M were measured.
在水介质中,通过联苯与5,5-二甲基-1-吡啶- n -氧化物(DMPO)之间的竞争反应,估计了羟基自由基(oh)与脱氢二丁香酚、厚朴酚、厚朴酚、脱氢二氢丁香酚、脱氢二苯基醇和脱氢二酚等联苯化合物之间反应的近似速率常数。通过测量。oh自旋加合物的EPR信号高度的下降,得到了10(9)~ 10(10)M量级的速率常数。
{"title":"Effective inhibition of hydroxyl radicals by hydroxylated biphenyl compounds.","authors":"J Taira, T Ikemoto, K Mimura, A Hagi, A Murakami, K Makino","doi":"10.3109/10715769309056s71","DOIUrl":"https://doi.org/10.3109/10715769309056s71","url":null,"abstract":"<p><p>In aqueous media, approximate rate constants for the reactions between hydroxyl radicals (.OH) and biphenyl compounds such as dehydrodieugenol, magnolol, honokiol, dehydrodidihydroeugenol, dehydrodivanillyl alcohol, and dehydrodicreosol were estimated by competition reactions for .OH between these biphenyls and 5,5-dimethyl-1-pyrroline-N-oxide (DMPO). By measuring the decrease in the height of the EPR signals of the .OH spin adduct, rate constants in the order of 10(9) to 10(10) M were measured.</p>","PeriodicalId":12438,"journal":{"name":"Free radical research communications","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1993-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3109/10715769309056s71","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"19270120","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1993-01-01DOI: 10.3109/10715769309056s149
T Shima, T Nakashima, K Kashima, H Nishikawa
We investigated the effect of membrane fluidity on the nitroxide radical decay rate of 5-doxyl stearic acid in spin-labeled rat hepatocytes. The half-time (t1/2) for the EPR signal decay of 5-doxyl stearic acids incorporated into the membranes of isolated rat hepatocytes was 12 min (mean value). When spin-labeled hepatocytes were separated into membrane and cytosol fractions, the t1/2 of the membrane fraction was prolonged by more than 2 hrs. However, when the cytosolic fraction was added to the membrane fraction, the radical decay reaction recovered (t1/2 was 27 min). Incubation of hepatocytes with a stream of 95% O2 at 37 degrees C for 2 hrs prolonged t1/2 by 106% and was associated with a 18% decrease in water-soluble antioxidant content. When the measurement temperature was changed from 24 degrees C to 37 degrees C, t1/2 was shortened with a decrease in the order parameter (S). The t1/2 and S in hepatocytes treated with phosphatidylcholine (PC) were reduced by 14% and 0.008, respectively. Conversely, after treatment with phosphatidylethanolamine (PE), PC+cholesterol and PE+cholesterol, t1/2 and S increased by 14% and 0.014, 20% and 0.018 and 29% and 0.040, respectively. These findings suggest that the nitroxide radical decay of 5-doxyl stearic acids incorporated into hepatocyte membranes is mediated by the antioxidants in the cytosol fraction, and that the nitroxide radical decay rate is affected not only by water-soluble antioxidant content but also by the membrane lipid fluidity of the hepatocytes.
{"title":"Membrane lipid fluidity affects the nitroxide radical decay of 5-doxyl stearic acids in isolated rat hepatocytes.","authors":"T Shima, T Nakashima, K Kashima, H Nishikawa","doi":"10.3109/10715769309056s149","DOIUrl":"https://doi.org/10.3109/10715769309056s149","url":null,"abstract":"<p><p>We investigated the effect of membrane fluidity on the nitroxide radical decay rate of 5-doxyl stearic acid in spin-labeled rat hepatocytes. The half-time (t1/2) for the EPR signal decay of 5-doxyl stearic acids incorporated into the membranes of isolated rat hepatocytes was 12 min (mean value). When spin-labeled hepatocytes were separated into membrane and cytosol fractions, the t1/2 of the membrane fraction was prolonged by more than 2 hrs. However, when the cytosolic fraction was added to the membrane fraction, the radical decay reaction recovered (t1/2 was 27 min). Incubation of hepatocytes with a stream of 95% O2 at 37 degrees C for 2 hrs prolonged t1/2 by 106% and was associated with a 18% decrease in water-soluble antioxidant content. When the measurement temperature was changed from 24 degrees C to 37 degrees C, t1/2 was shortened with a decrease in the order parameter (S). The t1/2 and S in hepatocytes treated with phosphatidylcholine (PC) were reduced by 14% and 0.008, respectively. Conversely, after treatment with phosphatidylethanolamine (PE), PC+cholesterol and PE+cholesterol, t1/2 and S increased by 14% and 0.014, 20% and 0.018 and 29% and 0.040, respectively. These findings suggest that the nitroxide radical decay of 5-doxyl stearic acids incorporated into hepatocyte membranes is mediated by the antioxidants in the cytosol fraction, and that the nitroxide radical decay rate is affected not only by water-soluble antioxidant content but also by the membrane lipid fluidity of the hepatocytes.</p>","PeriodicalId":12438,"journal":{"name":"Free radical research communications","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1993-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3109/10715769309056s149","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"19271055","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1993-01-01DOI: 10.3109/10715769309056s163
K Tsuda, I Nishio, Y Masuyama
The purpose of the present study was to examine alterations in membrane fluidity of erythrocytes in essential hypertension by means of an electron paramagnetic resonance (EPR) and a spin labeling method. In addition, we investigated the effects of ouabain on the fluidity of erythrocytes, and elucidated a possible role of Na+, K(+)-ATPase in the regulation of membrane fluidity in hypertension. Erythrocytes obtained from patients with essential hypertension were examined compared with those from age-matched normotensive subjects. The EPR spectra for 5-nitroxide stearate incorporated into erythrocyte membranes were studied. The values of the outer hyperfine splitting and order parameter (S) of the EPR spectra were significantly higher in patients with essential hypertension than in normotensive subjects. This finding shows that the membrane fluidity of erythrocytes might be lower in essential hypertension. Ouabain-loading of erythrocytes decreased the membrane fluidity (S value was increased). The ouabain-induced changes were significantly greater in essential hypertension than in normotensive subjects. These results demonstrate that the membrane fluidity of erythrocytes might be lower in essential hypertension than in normotensive subjects. Furthermore, the membrane fluidity might be highly dependent on the Na+, K(+)-ATPase activity in essential hypertension, which would suggest an abnormality in Na(+)-related cellular functions in hypertension.
{"title":"Membrane fluidity of erythrocytes and its modulation by ouabain in essential hypertension--an electron paramagnetic resonance study.","authors":"K Tsuda, I Nishio, Y Masuyama","doi":"10.3109/10715769309056s163","DOIUrl":"https://doi.org/10.3109/10715769309056s163","url":null,"abstract":"<p><p>The purpose of the present study was to examine alterations in membrane fluidity of erythrocytes in essential hypertension by means of an electron paramagnetic resonance (EPR) and a spin labeling method. In addition, we investigated the effects of ouabain on the fluidity of erythrocytes, and elucidated a possible role of Na+, K(+)-ATPase in the regulation of membrane fluidity in hypertension. Erythrocytes obtained from patients with essential hypertension were examined compared with those from age-matched normotensive subjects. The EPR spectra for 5-nitroxide stearate incorporated into erythrocyte membranes were studied. The values of the outer hyperfine splitting and order parameter (S) of the EPR spectra were significantly higher in patients with essential hypertension than in normotensive subjects. This finding shows that the membrane fluidity of erythrocytes might be lower in essential hypertension. Ouabain-loading of erythrocytes decreased the membrane fluidity (S value was increased). The ouabain-induced changes were significantly greater in essential hypertension than in normotensive subjects. These results demonstrate that the membrane fluidity of erythrocytes might be lower in essential hypertension than in normotensive subjects. Furthermore, the membrane fluidity might be highly dependent on the Na+, K(+)-ATPase activity in essential hypertension, which would suggest an abnormality in Na(+)-related cellular functions in hypertension.</p>","PeriodicalId":12438,"journal":{"name":"Free radical research communications","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1993-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3109/10715769309056s163","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"19271057","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1993-01-01DOI: 10.3109/10715769309056513
S Sen, J W Phillis
Alpha-phenyl-tert-butyl-nitrone (PBN) a spin adduct forming agent is believed to have a protective action in ischemia-reperfusion injury of brain by forming adducts of oxygen free radicals including .OH radical. Electron paramagnetic resonance (EPR) has been used to both detect and monitor the time course of oxygen free radical formation in the in vivo rat cerebral cortex. Cortical cups were placed over both cerebral hemispheres of methoxyflurane anesthetized rats prepared for four vessel occlusion-evoked cerebral ischemia. Prior to the onset of sample collection, both cups were perfused with artificial cerebrospinal fluid (aCSF) containing the spin trap agent alpha-(4-pyridyl-1-oxide)-N-tert butylnitrone (POBN 100 mM) for 20 min. In addition 50 mg/kg BW of POBN was administered intraperitoneally (IP) 20 min prior to ischemia in order to improve our ability to detect free radical adducts. Cup fluid was subsequently replaced every 15 min during ischemia and every 10 min during reperfusion with fresh POBN containing CSF and the collected cortical superfusates were analyzed for radical adducts by EPR spectroscopy. After a basal 10 min collection, cerebral ischemia was induced for 15 or 30 min (confirmed by EEG flattening) followed by a 90 min reperfusion. .OH radical adducts (characterized by six line EPR spectra) were detected during ischemia and 90 min reperfusion. No adduct was detected in the basal sample or after 90 min of reperfusion. Similar results were obtained when diethylenetriaminepenta-acetic acid (100 microM; DETAPAC) a chelating agent was included in the artificial CSF. Systemic administration of PBN (100 mg/kg BW) produced a significant attenuation of radical adduct during reperfusion. A combination of systemic and topical PBN (100 mM) was required to suppress .OH radical adduct formation during ischemia as well as reperfusion. PBN free radical adducts were detected in EPR spectra of the lipid extracts of PBN treated rat brains subjected to ischemia/reperfusion. Thus this study suggests that PBN's protective action in cerebral ischemia/reperfusion injury is related to its ability to prevent a cascade of free radical generation by forming spin adducts.
{"title":"alpha-Phenyl-tert-butyl-nitrone (PBN) attenuates hydroxyl radical production during ischemia-reperfusion injury of rat brain: an EPR study.","authors":"S Sen, J W Phillis","doi":"10.3109/10715769309056513","DOIUrl":"https://doi.org/10.3109/10715769309056513","url":null,"abstract":"<p><p>Alpha-phenyl-tert-butyl-nitrone (PBN) a spin adduct forming agent is believed to have a protective action in ischemia-reperfusion injury of brain by forming adducts of oxygen free radicals including .OH radical. Electron paramagnetic resonance (EPR) has been used to both detect and monitor the time course of oxygen free radical formation in the in vivo rat cerebral cortex. Cortical cups were placed over both cerebral hemispheres of methoxyflurane anesthetized rats prepared for four vessel occlusion-evoked cerebral ischemia. Prior to the onset of sample collection, both cups were perfused with artificial cerebrospinal fluid (aCSF) containing the spin trap agent alpha-(4-pyridyl-1-oxide)-N-tert butylnitrone (POBN 100 mM) for 20 min. In addition 50 mg/kg BW of POBN was administered intraperitoneally (IP) 20 min prior to ischemia in order to improve our ability to detect free radical adducts. Cup fluid was subsequently replaced every 15 min during ischemia and every 10 min during reperfusion with fresh POBN containing CSF and the collected cortical superfusates were analyzed for radical adducts by EPR spectroscopy. After a basal 10 min collection, cerebral ischemia was induced for 15 or 30 min (confirmed by EEG flattening) followed by a 90 min reperfusion. .OH radical adducts (characterized by six line EPR spectra) were detected during ischemia and 90 min reperfusion. No adduct was detected in the basal sample or after 90 min of reperfusion. Similar results were obtained when diethylenetriaminepenta-acetic acid (100 microM; DETAPAC) a chelating agent was included in the artificial CSF. Systemic administration of PBN (100 mg/kg BW) produced a significant attenuation of radical adduct during reperfusion. A combination of systemic and topical PBN (100 mM) was required to suppress .OH radical adduct formation during ischemia as well as reperfusion. PBN free radical adducts were detected in EPR spectra of the lipid extracts of PBN treated rat brains subjected to ischemia/reperfusion. Thus this study suggests that PBN's protective action in cerebral ischemia/reperfusion injury is related to its ability to prevent a cascade of free radical generation by forming spin adducts.</p>","PeriodicalId":12438,"journal":{"name":"Free radical research communications","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1993-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3109/10715769309056513","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"19282288","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1993-01-01DOI: 10.3109/10715769309056514
J Regnström, K Ström, P Moldeus, J Nilsson
The susceptibility of low density lipoprotein (LDL) to oxidative modification can be determined by analyzing the lag phase for initiation of diene formation in isolated LDL exposed to Cu2+. However, the applicability of this assay for clinical studies is limited by the requirement of a preparative ultracentrifugation of LDL and that the influence of water soluble antioxidants and other lipoproteins is not accounted for. The present paper describes a modification of this assay allowing determination of lag phase for lipoprotein diene formation in serum. The formation of dienes in serum exposed to Cu2+ begins following the consumption of serum alpha-tocopherol, correlates to the formation of thiobarbituric acid reactive substances (r = 0.987, n = 8), is inhibited by the addition of ascorbic acid and is absent in lipoprotein-deficient serum. It is also accompanied by an increased mobility of serum lipoproteins on agarose gel electrophoresis and with an ability of serum to displace isolated copper-oxidized LDL from binding sites mediating degradation in mouse peritoneal macrophages. The coefficient of variance of the analysis is below 3%. It is concluded that this technique allows analysis of lipoprotein oxidation susceptibility in serum samples and may prove to be useful in clinical analysis of the lipoprotein oxidation susceptibility.
低密度脂蛋白(LDL)对氧化修饰的易感性可以通过分析暴露于Cu2+的低密度脂蛋白启动二烯形成的滞后期来确定。然而,这种检测方法在临床研究中的适用性受到低密度脂蛋白制备超离心要求的限制,而且水溶性抗氧化剂和其他脂蛋白的影响也没有考虑在内。本文描述了一种改进的方法,允许测定血清中脂蛋白二烯形成的滞后期。暴露于Cu2+的血清中,二烯的形成始于血清α -生育酚的消耗,与硫代巴比妥酸反应物质的形成相关(r = 0.987, n = 8),被添加抗坏血酸抑制,在脂蛋白缺乏的血清中不存在。它还伴随着琼脂糖凝胶电泳上血清脂蛋白流动性的增加,以及血清从小鼠腹膜巨噬细胞中介导降解的结合位点取代分离的铜氧化LDL的能力。分析的方差系数在3%以下。结果表明,该技术可用于血清样品中脂蛋白氧化敏感性的分析,并可用于脂蛋白氧化敏感性的临床分析。
{"title":"Analysis of lipoprotein diene formation in human serum exposed to copper.","authors":"J Regnström, K Ström, P Moldeus, J Nilsson","doi":"10.3109/10715769309056514","DOIUrl":"https://doi.org/10.3109/10715769309056514","url":null,"abstract":"<p><p>The susceptibility of low density lipoprotein (LDL) to oxidative modification can be determined by analyzing the lag phase for initiation of diene formation in isolated LDL exposed to Cu2+. However, the applicability of this assay for clinical studies is limited by the requirement of a preparative ultracentrifugation of LDL and that the influence of water soluble antioxidants and other lipoproteins is not accounted for. The present paper describes a modification of this assay allowing determination of lag phase for lipoprotein diene formation in serum. The formation of dienes in serum exposed to Cu2+ begins following the consumption of serum alpha-tocopherol, correlates to the formation of thiobarbituric acid reactive substances (r = 0.987, n = 8), is inhibited by the addition of ascorbic acid and is absent in lipoprotein-deficient serum. It is also accompanied by an increased mobility of serum lipoproteins on agarose gel electrophoresis and with an ability of serum to displace isolated copper-oxidized LDL from binding sites mediating degradation in mouse peritoneal macrophages. The coefficient of variance of the analysis is below 3%. It is concluded that this technique allows analysis of lipoprotein oxidation susceptibility in serum samples and may prove to be useful in clinical analysis of the lipoprotein oxidation susceptibility.</p>","PeriodicalId":12438,"journal":{"name":"Free radical research communications","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1993-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3109/10715769309056514","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"19282289","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1993-01-01DOI: 10.3109/10715769309147501
M Hicks, L S Wong, R O Day
The aim of the present study was to separate and characterise products formed by oxidation of uric acid by hydroxyl radicals with a view to probing for these products in vivo in clinical contexts. Aerated solutions of 200 microM uric acid, or its oxidation products, allantoin or parabanic acid, were exposed to gamma radiolysis, (52.0 Gy/min), as a source of HO. radicals, at pH 3.4 and 7.4. Aliquots were taken every 5 minutes for 20 minutes and oxidation products were separated by HPLC and analysed with a diode array detector. Identities of oxidation products were confirmed on the basis of similarity of retention times and absorbance spectra and peak purity parameters of known standards. Hydroperoxides were measured by tri-iodide formation in the 20 minute sample. Exposure of uric acid to such HO.fluxes produced a net loss of the parent compound with formation of a complex mixture of products with allantoin and parabanic acid being the predominant products at pH 3.4. The rate of uric acid degradation at physiological pH was slower and the distribution of oxidation products was different. A small but significant amount of uric acid hydroperoxide was detected at both pHs. A mechanism for uric acid oxidation under these conditions is presented.
{"title":"Identification of products from oxidation of uric acid induced by hydroxyl radicals.","authors":"M Hicks, L S Wong, R O Day","doi":"10.3109/10715769309147501","DOIUrl":"https://doi.org/10.3109/10715769309147501","url":null,"abstract":"<p><p>The aim of the present study was to separate and characterise products formed by oxidation of uric acid by hydroxyl radicals with a view to probing for these products in vivo in clinical contexts. Aerated solutions of 200 microM uric acid, or its oxidation products, allantoin or parabanic acid, were exposed to gamma radiolysis, (52.0 Gy/min), as a source of HO. radicals, at pH 3.4 and 7.4. Aliquots were taken every 5 minutes for 20 minutes and oxidation products were separated by HPLC and analysed with a diode array detector. Identities of oxidation products were confirmed on the basis of similarity of retention times and absorbance spectra and peak purity parameters of known standards. Hydroperoxides were measured by tri-iodide formation in the 20 minute sample. Exposure of uric acid to such HO.fluxes produced a net loss of the parent compound with formation of a complex mixture of products with allantoin and parabanic acid being the predominant products at pH 3.4. The rate of uric acid degradation at physiological pH was slower and the distribution of oxidation products was different. A small but significant amount of uric acid hydroperoxide was detected at both pHs. A mechanism for uric acid oxidation under these conditions is presented.</p>","PeriodicalId":12438,"journal":{"name":"Free radical research communications","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1993-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3109/10715769309147501","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"19382629","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1993-01-01DOI: 10.3109/10715769309056504
T Tanigawa, Y Kotake, L A Reinke
Dahinden et al. reported that N-formylmethionyl-leucyl-phenylalanine (fMLP)-induced superoxide release from polymorphonuclear leukocytes (PMNs) lasted more than 60 min when the cells were allowed to attach to a petri dish before induction. In contrast, it lasted only for 2.5 min when cells were in suspension (J. Clin. Invest. 72: 113-121, 1983). In spite of this report, the effect of cell adhesion has been ignored in most spin trapping studies of superoxide release from PMNs. This study shows that most PMNs in a quartz flat electron paramagnetic resonance (EPR) cuvette which was placed horizontally adhered to the wall within 3 min. In contrast, if the cuvette was placed vertically, only 20-30% of the cells became adherent in 30 min. We performed spin trapping studies using 5,5-dimethylpyrroline-N-oxide (DMPO) as a spin trap, and monitored the effect of cell adhesion on superoxide generation. When spin trapping was conducted on PMNs in suspension, the EPR signal of superoxide adduct (DMPO-OOH) was undetectable after stimulation with fMLP. However, PMNs which were allowed to adhere to the cuvette after stimulation generated superoxide for hours. Moreover, when PMNs were allowed to adhere prior to the stimulation, the magnitude of superoxide release was augmented three-to fourfold. Unlike fMLP, phorbol myristate acetate (PMA), which has been most commonly used in spin trapping studies, induced superoxide release which was not influenced by cell adhesion. We emphasize the importance of specifying the cell-adhesion-state in spin trapping studies.
Dahinden等人报道,n -甲酰基蛋氨酸-亮氨酸-苯丙氨酸(fMLP)诱导的多形核白细胞(PMNs)的超氧化物释放持续超过60分钟,在诱导前将细胞附着在培养皿上。相比之下,当细胞处于悬浮状态时,其持续时间仅为2.5 min (J. Clin;投资。72:113-121,1983)。尽管有这样的报道,但在大多数关于PMNs释放超氧化物的自旋捕获研究中,细胞粘附的影响被忽略了。本研究表明,在石英平面电子顺磁共振(EPR)试管中,水平放置的大多数pmn在3分钟内粘附在壁上。相反,如果垂直放置试管,只有20-30%的细胞在30分钟内粘附在壁上。我们使用5,5-二甲基吡咯啉- n -氧化物(DMPO)作为自旋阱进行了自旋捕获研究,并监测细胞粘附对超氧化物产生的影响。在悬浮PMNs上进行自旋捕获时,fMLP刺激后,超氧化物加合物(DMPO-OOH)的EPR信号无法检测到。然而,刺激后让PMNs粘附在小皿上数小时产生超氧化物。此外,当刺激前允许pmn粘附时,超氧化物释放的幅度增加了三到四倍。与fMLP不同,在自旋捕获研究中最常用的肉豆蔻酸酯phorbol acetate (PMA)诱导超氧化物释放,而超氧化物释放不受细胞粘附的影响。我们强调了在自旋捕获研究中明确细胞粘附状态的重要性。
{"title":"Spin trapping of superoxide from glass adherent polymorphonuclear leukocytes induced by N-formylmethionyl-leucyl-phenylalanine.","authors":"T Tanigawa, Y Kotake, L A Reinke","doi":"10.3109/10715769309056504","DOIUrl":"https://doi.org/10.3109/10715769309056504","url":null,"abstract":"<p><p>Dahinden et al. reported that N-formylmethionyl-leucyl-phenylalanine (fMLP)-induced superoxide release from polymorphonuclear leukocytes (PMNs) lasted more than 60 min when the cells were allowed to attach to a petri dish before induction. In contrast, it lasted only for 2.5 min when cells were in suspension (J. Clin. Invest. 72: 113-121, 1983). In spite of this report, the effect of cell adhesion has been ignored in most spin trapping studies of superoxide release from PMNs. This study shows that most PMNs in a quartz flat electron paramagnetic resonance (EPR) cuvette which was placed horizontally adhered to the wall within 3 min. In contrast, if the cuvette was placed vertically, only 20-30% of the cells became adherent in 30 min. We performed spin trapping studies using 5,5-dimethylpyrroline-N-oxide (DMPO) as a spin trap, and monitored the effect of cell adhesion on superoxide generation. When spin trapping was conducted on PMNs in suspension, the EPR signal of superoxide adduct (DMPO-OOH) was undetectable after stimulation with fMLP. However, PMNs which were allowed to adhere to the cuvette after stimulation generated superoxide for hours. Moreover, when PMNs were allowed to adhere prior to the stimulation, the magnitude of superoxide release was augmented three-to fourfold. Unlike fMLP, phorbol myristate acetate (PMA), which has been most commonly used in spin trapping studies, induced superoxide release which was not influenced by cell adhesion. We emphasize the importance of specifying the cell-adhesion-state in spin trapping studies.</p>","PeriodicalId":12438,"journal":{"name":"Free radical research communications","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1993-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3109/10715769309056504","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"19214315","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1993-01-01DOI: 10.3109/10715769309056526
X R Jiang, M Yang, C J Morris, A C Newland, D P Naughton, D R Blake, Z Zhang, M C Grootveld
High field proton (1H) nuclear magnetic resonance (NMR) spectroscopy has for the first time been employed to investigate and compare the metabolic profiles of vinblastine-sensitive and -resistant T-lymphoid leukaemic cell lines (CCRF-CEM and CEM/VLB100 respectively) and evidence is presented for a significantly lower taurine content in the CEM/VLB100 resistant subline when expressed relative to that of its drug-sensitive parental counterpart. These data suggest differences in the nature and relative involvements of taurine biosynthetic pathways between the two cell lines, a phenomenon that may be related to their differing sensitivities towards chemotherapeutic agents such as adriamycin which promote the generation of cytotoxic reactive oxygen species (ROS) in vivo. However, the 1H NMR data obtained provided no evidence for an increased metabolic consumption of hypotaurine (a metabolic precursor of taurine with powerful .OH radical scavenging properties) in CCRF-CEM cells since differences observed in the hypotaurine: taurine concentration ratio between the drug-sensitive and -resistant cell lines were not statistically significant. Furthermore, hypotaurine is unlikely to compete with alternative endogenous .OH radical scavengers present such as lactate since its level in either of the two cell lines investigated (ca. 6.0 x 10(-8) mol./10(8) cells) is insufficient for it to act as an antioxidant in this context. The biochemical and therapeutic significance of these results are discussed.
{"title":"High field proton NMR investigations of the metabolic profiles of multidrug-sensitive and -resistant leukaemic cell lines: evidence for diminished taurine levels in multidrug-resistant cells.","authors":"X R Jiang, M Yang, C J Morris, A C Newland, D P Naughton, D R Blake, Z Zhang, M C Grootveld","doi":"10.3109/10715769309056526","DOIUrl":"https://doi.org/10.3109/10715769309056526","url":null,"abstract":"<p><p>High field proton (1H) nuclear magnetic resonance (NMR) spectroscopy has for the first time been employed to investigate and compare the metabolic profiles of vinblastine-sensitive and -resistant T-lymphoid leukaemic cell lines (CCRF-CEM and CEM/VLB100 respectively) and evidence is presented for a significantly lower taurine content in the CEM/VLB100 resistant subline when expressed relative to that of its drug-sensitive parental counterpart. These data suggest differences in the nature and relative involvements of taurine biosynthetic pathways between the two cell lines, a phenomenon that may be related to their differing sensitivities towards chemotherapeutic agents such as adriamycin which promote the generation of cytotoxic reactive oxygen species (ROS) in vivo. However, the 1H NMR data obtained provided no evidence for an increased metabolic consumption of hypotaurine (a metabolic precursor of taurine with powerful .OH radical scavenging properties) in CCRF-CEM cells since differences observed in the hypotaurine: taurine concentration ratio between the drug-sensitive and -resistant cell lines were not statistically significant. Furthermore, hypotaurine is unlikely to compete with alternative endogenous .OH radical scavengers present such as lactate since its level in either of the two cell lines investigated (ca. 6.0 x 10(-8) mol./10(8) cells) is insufficient for it to act as an antioxidant in this context. The biochemical and therapeutic significance of these results are discussed.</p>","PeriodicalId":12438,"journal":{"name":"Free radical research communications","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1993-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3109/10715769309056526","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"19158985","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}