Institut für Mangostan & natürliche Antioxidantien

Freie Radikale & Oxidativer Stress

Aktuelle wissenschaftliche Studien | 21-40

21: Clin Exp Pharmacol Physiol. 2008 Jan;35(1):64-71.
Related Articles, Links

Hyperoxia confers myocardial protection in mechanically ventilated rats through the generation of free radicals and opening of mitochondrial ATP-sensitive potassium channels.

Colantuono G, Tiravanti EA, Di Venosa N, Cazzato A, Rastaldo R, Cagiano R, D'Agostino D, Federici A, Fiore T.

Department of Emergency and Transplants, Section of Anaesthesia and Critical Care, University of Bari, Bari, Italy.

1. One hour exposure to hyperoxia has been shown previously to limit a subsequent ischaemia-reperfusion injury in spontaneously breathing rats. We tested the cardioprotective effect of a shorter period of hyperoxia during mechanical ventilation and the possible contribution of reactive oxygen species (ROS) and mitochondrial ATP-sensitive potassium (mitoK(ATP)) channels. 2. Mechanically ventilated rats were exposed to normoxia (Fi O2 = 0.3) or hyperoxia (Fi O2 = 1.0) for 30 min and pH, P CO2, PO2, heart rate, airway and blood pressure were measured at baseline and after 30 min mechanical ventilation. Isolated hearts were subsequently subjected to 30 min ischaemia and 120 min reperfusion. Infarct size and left ventricular end-diastolic pressure (LVEDP), developed pressure (LVDP) and coronary flow (CF) were measured. In order to investigate the role of ROS and KATP channels within the mechanism leading to cardioprotection, the free radical scavenger N-acetylcysteine (NAC; 150 mg/kg) was infused in mechanically ventilated rats and the KATP channel blockers glibenclamide (200 mmol/L) or 5-hydroxydecanoate (10 mmol/L) were infused in isolated hearts immediately before ischaemia. 3. No differences were detected in P CO2, pH, heart rate, airway and blood pressure between the groups. However, the PO2 in hyperoxic groups was significantly higher compared with that in normoxic groups (P < 0.01). After 30 min ischaemia, we found that hyperoxic preconditioning significantly improved CF (P < 0.01), LVDP (P < 0.01) and LVEDP (P < 0.01) and reduced the extent of infarct size in the reperfused heart compared with the normoxic group (P < 0.01). When rats were pretreated either with NAC before hyperoxic ventilation or with K(ATP) channel blockers before ischaemia, myocardial protection was abolished. 4. Hyperoxic mechanical ventilation, prior to ischaemia, reduces myocardial reperfusion injury. This is likely to occur through the induction of oxidative stress, which leads to myocyte mitoKATP channel opening.

PMID: 18047630 [PubMed - indexed for MEDLINE]

22: Clin Interv Aging. 2007;2(2):219-36.
Related Articles, Links

Studies on free radicals, antioxidants, and co-factors.

Rahman K.

School of Biomolecular Sciences, Liverpool John Moores University, Liverpool, England, UK.

The interplay between free radicals, antioxidants, and co-factors is important in maintaining health, aging and age-related diseases. Free radicals induce oxidative stress, which is balanced by the body's endogenous antioxidant systems with an input from co-factors, and by the ingestion of exogenous antioxidants. If the generation of free radicals exceeds the protective effects of antioxidants, and some co-factors, this can cause oxidative damage which accumulates during the life cycle, and has been implicated in aging, and age dependent diseases such as cardiovascular disease, cancer, neurodegenerative disorders, and other chronic conditions. The life expectancy of the world population is increasing, and it is estimated that by 2025, 29% of the world population will be aged > or = 60 years, and this will lead to an increase in the number of older people acquiring age-related chronic diseases. This will place greater financial burden on health services and high social cost for individuals and society. In order to acheive healthy aging the older people should be encouraged to acquire healthy life styles which should include diets rich in antioxidants. The aim of this review is to highlight the main themes from studies on free radicals, antioxidants and co-factors, and to propose an evidence-based strategy for healthy aging.

Publication Types:

PMID: 18044138 [PubMed - indexed for MEDLINE]

23: Chem Res Toxicol. 2007 Dec;20(12):1885-94. Epub 2007 Oct 18.
Related Articles, Links
Click here to read
Oxidative metabolism of combretastatin A-1 produces quinone intermediates with the potential to bind to nucleophiles and to enhance oxidative stress via free radicals.

Folkes LK, Christlieb M, Madej E, Stratford MR, Wardman P.

University of Oxford, Gray Cancer Institute, Mount Vernon Hospital, Middlesex, UK.

Combretastatins are stilbene-based, tubulin depolymerization agents with selective activity against the tumor vasculature; two variants (A-1 and A-4) are currently undergoing clinical trials. Combretastatin A-1 (CA1) has a greater antitumor effect than combretastatin A-4 (CA4). We hypothesized that this reflects the enhanced reactivity conferred by the second (ortho) phenolic moiety in CA1. Oxidation of CA1 by peroxidase, tyrosinase, or Fe(III) generates a species with mass characteristics of the corresponding ortho-quinone Q1. After administration of CA1-bis(phosphate) to mice, the hydroquinone-thioether conjugate Q1H2-SG, formed from the nucleophilic addition of GSH to Q1, was detected in liver. In competition, electrocyclic ring closure of Q1, over a few minutes at pH 7.4, leads to a second ortho-quinone product Q2, characterized by exact mass and NMR. This product was also generated by human promyelocytic leukemia (HL-60) cells in vitro, provided that superoxide dismutase was added. Q2 is highly reactive toward glutathione (GSH) and ascorbate, stimulating oxygen consumption in a catalytic manner. Free radical intermediates formed during autoxidation of CA1 were characterized by EPR, and the effects of GSH and ascorbate on the signals were studied. Pulse radiolysis was used to initiate selective one-electron oxidation or reduction and provided further evidence, from the differing absorption spectra of the radicals formed on oxidation of CA1 or reduction of Q2, that two different quinones were formed on oxidation of CA1. The results demonstrate fundamental differences between the pharmacological properties of CA1 and CA4 that provide two possible explanations for their differential activities in vivo: oxidative activation to a quinone intermediate likely to bind to protein thiols and possibly to nucleic acids and stimulation of oxidative stress by enhancing superoxide/hydrogen peroxide production. The observation of the GSH conjugate Q1H2-SG in vivo provides a new marker for oxidative metabolism of relevance to current clinical trials of CA1-bis(phosphate) (OXi4503).

Publication Types:

PMID: 17941699 [PubMed - indexed for MEDLINE]

24: Neurosci Res. 2008 Jan;60(1):10-4. Epub 2007 Sep 12.
Related Articles, Links
Click here to read
Different response between production of free radicals induced by central and peripheral administration of interleukin-1beta in conscious rats.

Ishizuka Y, Abe H, Nakane H, Kannan H, Ishida Y.

Department of Psychiatry, Faculty of Medicine, University of Miyazaki, 5200 Kihara, Miyazaki 889-1692, Japan.

We examined whether central or peripheral administration of interleukin-1beta (IL-1beta) might change levels of nitric oxide (NO) and hydroxyl radical (*OH) in the medial prefrontal cortex (mPFC). Extracellular levels of NO metabolites (NOx(-)) and 2,3-dihydroxybenzoic acid (2,3-DHBA), as a marker of *OH production, were determined with an in vivo microdialysis technique in conscious rats. In the mPFC, central administration of IL-1beta into the mPFC resulted in dose-dependent increases in levels of both NOx(-) and 2,3-DHBA. In contrast, peripheral administration of IL-1beta significantly increased NOx(-) levels but not 2,3-DHBA levels. Perfusion of Mn(III) tetrakis (4-benzoic acid) porphyrin chloride, a superoxide (O(2)(-)) dismutase mimic, into the mPFC reduced the increases in levels of 2,3-DHBA induced by centrally administered IL-1beta, but enhanced the increases in levels of NOx(-) induced by centrally administered IL-1beta. The present results show a different response in free radical productions in the mPFC between central and peripheral administration of IL-1beta. This finding should be useful for our understanding of the response of NO and free radicals such as *OH and O(2)(-) in the mPFC after central and peripheral administration of IL-1beta.

PMID: 17920716 [PubMed - indexed for MEDLINE]

25: J Appl Physiol. 2007 Dec;103(6):1917-8. Epub 2007 Oct 4.
Related Articles, Links
Click here to read
Comment on:

Physiological role of free radicals in skeletal muscles.

Lecarpentier Y.

Publication Types:

PMID: 17916668 [PubMed - indexed for MEDLINE]

26: Mol Biotechnol. 2007 Sep;37(1):62-5.
Related Articles, Links

Role of ascorbic acid in scavenging free radicals and lead toxicity from biosystems.

Tariq SA.

Free radicals are reactive species that are responsible for damaging normal cells and creating diseases in humans. Antioxidants from natural resources or as supplements can scavenge these radicals. A MedLine search indicates that vitamin C is the most investigated antioxidant responsible for the elimination of free radicals. Its chelating property for the removal of neurotoxic lead, which creates oxidative stress in the human biosystem, was investigated and results indicate its great potential as a lead-detoxifying agent.

Publication Types:

PMID: 17914166 [PubMed - indexed for MEDLINE]

27: Mol Biotechnol. 2007 Sep;37(1):2-4.
Related Articles, Links

Signaling functions of free radicals superoxide & nitric oxide under physiological & pathological conditions.

Afanas'ev IB.

Vitamin Research Institute, Moscow, Russia.

Superoxide and nitric oxide are ubiquitous physiological free radicals that are responsible for many pathological disorders. Both radicals by themselves are relatively harmless but are the precursors of many toxic species such as peroxy and hydroxyl radicals, hydrogen peroxide, and peroxynitrite. However, it has been shown now that both superoxide and nitric oxide are also able to perform important signaling functions in physiological and pathophysiological processes. Wrongly named "superoxide," the radical anion of dioxygen is not a super-oxidant but the strong super-nucleophile, an efficient catalyst of heterogenic nucleophilic reaction. Due to this, superoxide plays an important role in many enzymatic processes such as the phosphorylation and activation of numerous protein kinases. On the other hand, superoxide inhibits the activation of phosphatases, the enzymes catalyzed by dephosphorylation of protein kinases. We suggest that superoxide catalyzes these enzymatic processes as a result of its nucleophilic properties. Another important physiological function of superoxide and nitric oxide is their competition for the interaction with mitochondrial cytochrome c oxidase. Disturbance of superoxide/nitric oxide balance leads to the dysfunction of mitochondria and the enhancement of apoptosis and oxidative stress, which are primary causes of various pathological disorders and aging. In conclusion, interplay between superoxide and nitric oxide, one of major factors of aging development, is considered.

Publication Types:

PMID: 17914156 [PubMed - indexed for MEDLINE]

28: Eur J Pharmacol. 2007 Dec 22;577(1-3):183-91. Epub 2007 Sep 11.
Related Articles, Links
Click here to read
Curcumin prevents streptozotocin-induced islet damage by scavenging free radicals: a prophylactic and protective role.

Meghana K, Sanjeev G, Ramesh B.

National Centre for Cell Science, Pune, India.

Pancreatic islet cell death is the cause of deficient insulin production in diabetes mellitus. Approaches towards prevention of cell death are of prophylactic importance in control and management of hyperglycemia. Generation of oxidative stress is implicated in streptozotocin, a beta cell specific toxin-induced islet cell death. In this context, antioxidants raise an interest for therapeutic purposes. Curcumin, a common dietary spice is a well known antioxidant and hence we investigated its effect on streptozotocin-induced islet damage in vitro. Isolated islets from C57/BL6J mice were incubated with curcumin for 24 h and later exposed to streptozotocin for 8 h. The effect of streptozotocin exposure to islets was determined with respect to islet viability and functionality, cellular reactive oxygen species concentrations and levels of activated poly (ADP-ribose) polymerase-1. Cellular antioxidant potential (Cu/Zn superoxide dismutase) and advanced glycation end-product related damage was assessed to determine the metabolic status of treated and untreated islets. Islet viability and secreted insulin in curcumin pretreated islets were significantly higher than islets exposed to streptozotocin alone. Curcumin retarded generation of islet reactive oxygen species along with inhibition of Poly ADP-ribose polymerase-1 activation. Although curcumin did not cause overexpression of Cu/Zn superoxide dismutase, it prevented reduction in levels of cellular free radical scavenging enzymes. Our data shows that curcumin protects islets against streptozotocin-induced oxidative stress by scavenging free radicals. We show here for the first time, that prophylactic use of curcumin may effectively rescue islets from damage without affecting the normal function of these cellular structures.

Publication Types:

PMID: 17900558 [PubMed - indexed for MEDLINE]

29: Food Chem Toxicol. 2008 Jan;46(1):359-67. Epub 2007 Aug 19.
Related Articles, Links
Click here to read
Phenoxyherbicides induce production of free radicals in human erythrocytes: oxidation of dichlorodihydrofluorescine and dihydrorhodamine 123 by 2,4-D-Na and MCPA-Na.

Bukowska B, Rychlik B, Krokosz A, Michałowicz J.

Department of Biophysics of Environmental Pollution, University of Łódź, Banacha 12/16, 90-237 Łódź, Poland.

Although it is known that phenoxyacetic herbicides significantly affect the oxidative status of human erythrocytes, there is no direct evidence of their ability to induce free radical production. To demonstrate this phenomenon we investigated the effect of two commonly used phenoxyherbicides-sodium salt of 2,4-dichlorophenoxyacetic acid (2,4-D-Na) and sodium salt of 4-chloro-2-methylphenoxyacetic acid (MCPA-Na) on oxidation of dihydrorhodamine 123 and H(2)DCFDA as well as on carbonyl group content in cellular proteins. Moreover, haemoglobin denaturation was also measured. The rate of fluorescent probe oxidation was significantly higher for 2,4-D-Na, while both compounds exerted similar effects on protein carbonyl group (an increase in their content) and on denaturation of haemoglobin (no changes were observed). These results and the previous data led us to a conclusion that pro-oxidative action of phenoxyherbicides is strongly dependent on the localization of the substituent in the phenol ring. We also proposed a metabolic reaction chain that explains the mechanism of action of 2,4-D-Na in vivo.

Publication Types:

PMID: 17889420 [PubMed - indexed for MEDLINE]

30: Br J Pharmacol. 2007 Dec;152(7):1033-41. Epub 2007 Sep 3.
Related Articles, Links
Click here to read
Oxygen-derived free radicals mediate endothelium-dependent contractions in femoral arteries of rats with streptozotocin-induced diabetes.

Shi Y, So KF, Man RY, Vanhoutte PM.

Department of Pharmacology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, SAR, China.

BACKGROUND AND PURPOSE:The present experiments were designed to study the contribution of oxygen-derived free radicals to endothelium-dependent contractions in femoral arteries of rats with streptozotocin-induced diabetes. EXPERIMENTAL APPROACH: Rings with and without endothelium were suspended in organ chambers for isometric tension recording. The production of oxygen-derived free radicals in the endothelium was measured with 2',7'-dichlorodihydrofluorescein diacetate using confocal microscopy. The presence of protein was measured by western blotting. KEY RESULTS: In the presence of L-NAME, the calcium ionophore A23187 induced larger endothelium-dependent contractions in femoral arteries from diabetic rats. Tiron, catalase, deferoxamine and MnTMPyP, but not superoxide dismutase reduced the response, suggesting that oxygen-derived free radicals are involved in the endothelium-dependent contraction. In the presence of L-NAME, A23187 increased the fluorescence signal in femoral arteries from streptozotocin-treated, but not in those from control rats, confirming that the production of oxygen-derived free radicals contributes to the enhanced endothelium-dependent contractions in diabetes. Exogenous H2O2 caused contractions in femoral arterial rings without endothelium which were reduced by deferoxamine, indicating that hydroxyl radicals contract vascular smooth muscle and thus could be an endothelium-derived contracting factor in diabetes. The reduced presence of Mn-SOD and the decreased activity of catalase in femoral arteries from streptozotocin-treated rats demonstrated the presence of a redox abnormality in arteries from rats with diabetes. CONCLUSIONS AND IMPLICATIONS: These findings suggest that the redox abnormality resulting from diabetes increases oxidative stress which facilitates and/or causes endothelium-dependent contractions.

Publication Types:

PMID: 17767168 [PubMed - indexed for MEDLINE]
PMCID: PMC2095103 [Available on 12/01/08]

31: FEBS Lett. 2007 Sep 4;581(22):4349-54. Epub 2007 Aug 14.
Related Articles, Links
Click here to read
Cholesterol is more susceptible to oxidation than linoleates in cultured cells under oxidative stress induced by selenium deficiency and free radicals.

Saito Y, Yoshida Y, Niki E.

Human Stress Signal Research Center, National Institute of Advanced Industrial Science and Technology (AIST), Ikeda, Osaka 563-8577, Japan.

Polyunsaturated fatty acids and their esters are known to be susceptible to free-radical mediated oxidation, while cholesterol is more resistant to oxidation. The present study focused on the relative susceptibilities of linoleates and cholesterol in Jurkat cells under oxidative stress induced by selenium deficiency and free radical insult, as assessed by total hydroxyoctadecadienoic acids (tHODE) and total 7-hydroxycholesterol (t7-OHCh) measured after reduction and saponification. It was observed that the levels of tHODE and t7-OHCh significantly increased by both oxidative insults. The increased amounts of t7-OHCh were higher than those of tHODE in both selenium-deficient and free radical-treated cells. These results suggest that, in contrast to plasma oxidation where cholesterol is much more resistant to oxidation than linoleates, cellular cholesterol is more susceptible to oxidation than cellular linoleates.

Publication Types:

PMID: 17716664 [PubMed - indexed for MEDLINE]

32: Gen Physiol Biophys. 2007 Jun;26(2):71-4.
Related Articles, Links
Click here to read
Cogitation about free radicals and oxidative stress--an old concept with many new limitations.

Ziegelhöffer A.

Institute for Heart Research, Centre of Excellence for Cardiovascular Research of Slovak Academy of Sciences, Dúbravská cesta 9, 840 05 Bratislava 45, Slovakia.

Since its creation, the concept of OS became very popular. Manifestations of the OS were investigated, verified, proved and disproved in thousands of studies. However, the enormous amount of knowledge about OS that accumulated in the last decades had dual influence: it extended the original concept of OS considerably, often even in an undesirable way, but it also pointed to its vulnerability. The present treatise is a cogitation about some main limitations that can make the original concept of OS outdated. No matter whether outdated or only less exact, it would be better to think it over three times prior using the term OS.

Publication Types:

PMID: 17660579 [PubMed - indexed for MEDLINE]

33: Anal Chem. 2007 Aug 15;79(16):6236-48. Epub 2007 Jul 19.
Related Articles, Links
Click here to readClick here to read
Top-down and bottom-up mass spectrometric characterization of human myoglobin-centered free radicals induced by oxidative damage.

Deterding LJ, Bhattacharjee S, Ramirez DC, Mason RP, Tomer KB.

Laboratory of Structural Biology, National Institute of Environmental Health Sciences, National Institutes of Health, P.O. Box 12233, MD F0-03, Research Triangle Park, North Carolina 27709, USA.

In an effort to determine the utility of top-down mass spectrometric methodologies for the characterization of protein radical adducts, top-down approaches were investigated and compared to the traditional bottom-up approaches. Specifically, the nature of the radicals on human myoglobin induced by the addition of hydrogen peroxide and captured by the spin trap 5,5-dimethyl-1-pyrroline N-oxide (DMPO) was investigated. The most abundant ion observed in the electrospray mass spectrum of this reaction mixture corresponds in mass to the human myoglobin plus one DMPO molecule. In addition, a second ion of lower abundance is observed, which corresponds to a second DMPO molecule being trapped on myoglobin. Top-down analyses using Fourier transform ion cyclotron resonance mass spectrometry can be used to characterize proteins and, thus, were performed on several different charge-state ions of both the native and the mono-DMPO nitrone adduct of human myoglobin. Data produced from the top-down analyses are very complex yet information rich. In the case of DMPO-modified human myoglobin, the top-down data localized the DMPO spin trap to residues 97-110 of the myoglobin. The observation of the y43+5 fragment ion arising from C-terminal cleavage to the cysteine-110 residue in the MS/MS spectrum of DMPO-modified myoglobin and not in the unmodified myoglobin implicates a change to this residue, specifically, DMPO adduction. On the other hand, using the traditional bottom-up approach of peptide mapping and MS sequencing methodologies, two DMPO radical adducts on human myoglobin were identified, Cys-110 and Tyr-103. The bottom-up approach is more proven and robust than the top-down methodologies. Nonetheless, the bottom-up and top-down approaches to protein characterization are complementary rather than competitive approaches with each having its own utility.

Publication Types:

PMID: 17637042 [PubMed - indexed for MEDLINE]
PMCID: PMC2376835

34: Ceska Slov Farm. 2007 Apr;56(2):73-6.
Related Articles, Links

[Antioxidants, free radicals, mechanism of action and application in the therapy of the sulfur mustard caused injury]

[Article in Czech]

Koleckár V, Brojerová E, Opletal L, Jun D, Kuca K.

Univerzita Karlova v Praze, Farmaceutická fakulta v Hradci Králové, Katedra farmaceutické botaniky a ekologie.

Antioxidants perform an important role in the maintenance of the integrity of the living organisms. Recently, great attention has been given to antioxidants by a reason of their medical use. It is due to the association of many human diseases with oxidative stress. The present study briefly surveys the types of antioxidants, reactive oxygen and nitrogen species and describes the basic mechanisms of their activity. The application of antioxidants in the therapy of the injury caused by sulfur mustard, a vesicant type chemical warfare agent introduced in World War I, is also given.

Publication Types:

PMID: 17619303 [PubMed - indexed for MEDLINE]

35: Cell Mol Biol (Noisy-le-grand). 2007 May 30;53(5):19-28.
Related Articles, Links

Pesticides and metals induced Parkinson's disease: involvement of free radicals and oxidative stress.

Singh C, Ahmad I, Kumar A.

Industrial Toxicology Research Centre, Mahatma Gandhi Marg, Lucknow, UP, India.

Environmental factors play a critical role in the etiology of Parkinson's disease in genetically susceptible aged individuals. Epidemiological findings have suggested the role of pesticides and metals in the onset and progression of Parkinson's disease. Environmental chemicals such as pesticides and metals induced PD animal models are established and evidences obtained from biochemical; molecular and behavioral studies indicated significant contribution of oxidative stress in PD. In this article, an update on the role of free radicals and antioxidants in the onset and progression of pesticides and metals induced PD has been discussed.

Publication Types:

PMID: 17543230 [PubMed - indexed for MEDLINE]

36: Cell Mol Biol (Noisy-le-grand). 2007 Apr 15;53(1):1-2.
Related Articles, Links

Role of free radicals and antioxidants in health and disease.

Flora SJ.

Division of Pharmacology and Toxicology- Defence Research and Development Establishment Jhansi Road, Gwalior 474 002, India.

Publication Types:

PMID: 17535753 [PubMed - indexed for MEDLINE]

37: Nippon Rinsho. 2006 Oct 28;64 Suppl 7:151-5.
Related Articles, Links

[Reactive oxygen species and free radicals are involved in pathophysiology of brain ischemia]

[Article in Japanese]

Naito Y, Yoshikawa T.

Medical Proteomics, Kyoto Prefectural University of Medicine.

Publication Types:

PMID: 17461142 [PubMed - indexed for MEDLINE]

38: J Am Coll Cardiol. 2007 Apr 24;49(16):1722-32. Epub 2007 Apr 5.
Related Articles, Links
Click here to read
Scavenging free radicals by low-dose carvedilol prevents redox-dependent Ca2+ leak via stabilization of ryanodine receptor in heart failure.

Mochizuki M, Yano M, Oda T, Tateishi H, Kobayashi S, Yamamoto T, Ikeda Y, Ohkusa T, Ikemoto N, Matsuzaki M.

Department of Medicine and Clinical Science, Division of Cardiology, Yamaguchi University Graduate School of Medicine, Ube, Japan.

OBJECTIVES: We investigated whether defective intracellular Ca2+ handling is corrected by carvedilol in heart failure. BACKGROUND: In heart failure, the interaction between the N-terminal and central domains of the ryanodine receptor (RyR), the domains where many mutations have been found in patients with catecholaminergic polymorphic ventricular tachycardia (CPVT), is defective, as shown in our recent report. METHODS: Sarcoplasmic reticulum vesicles were isolated from canine left ventricular muscle (normal or 4-weeks rapid ventricular pacing). The RyR was labeled with the fluorescent conformational probe methylcoumarin acetate (MCA) with DPc10 (a synthetic peptide corresponding to Gly2460-Pro2495 of RyR, one of the mutable domains in CPVT) as a site-direction carrier. RESULTS: Normal cardiac function was well preserved in carvedilol-treated/paced dogs (CV+) but not in the untreated/paced dogs (CV-). In CV-, the interdomain interaction within RyR was defective (i.e., in an unzipped state), as determined by the fluorescence quenching technique. However, in CV+, the domain interaction remained normal (i.e., in a zipped state). In CV-, oxidative stress of RyR (reduction in the number of free thiols) was severe, but it was negligible in CV+. In (CV-) failing cardiomyocytes, incubation with low-dose CV (30 nmol/l), which eliminated intracellular reactive oxygen species with no acute effect on cell shortening, markedly improved the contractile function and Ca2+ transient. However, after domain unzipping by DPc10, CV was without effect. CONCLUSIONS: Carvedilol, at a concentration that is sufficient to produce antioxidant effect, improves the intracellular Ca2+ handling and contractile dysfunction by correcting defective interdomain interaction within the RyR in the failing heart.

Publication Types:

PMID: 17448375 [PubMed - indexed for MEDLINE]

39: Ying Yong Sheng Tai Xue Bao. 2007 Jan;18(1):129-32.
Related Articles, Links

[Free radicals in Carassius auratus liver: their generation and oxidative stress induced by 2,4,6-trichlorophenol]

[Article in Chinese]

Ji LL, Li FY, Luo Y, Ma XP, Chen ZL.

School of Resources and Environment, Liaoning University, Shenyang 110036, China.

With electron paramagnetic resonance (EPR) technique, this paper studied the free radicals generation and oxidative stress in Carassius auratus liver after 4, 8, 12, 24 and 72 hours of 2, 4,6-trichlorophenol (2,4,6-TCP) intraperitoneal injection. The results showed that 2,4,6-TCP significantly promoted the generation of free radicals in C. auratus liver. The superoxide dismutase (SOD) and glutathione-S-transferase (GST) activities were induced significantly, while catalase (CAT) activity was inhibited, and glutathione (GSH) content had little difference with the control. A significant increase was observed in the contents of oxidized glutathione (GSSG) and malondialdehyde (MDA).

Publication Types:

PMID: 17396512 [PubMed - indexed for MEDLINE]

40: Biometals. 2007 Oct;20(5):793-6. Epub 2007 Mar 28.
Related Articles, Links
Click here to read
Iron-citrate complexes and free radicals generation: is citric acid an innocent additive in foods and drinks?

Gautier-Luneau I, Bertet P, Jeunet A, Serratrice G, Pierre JL.

Laboratoire de Chimie Biomimétique, LEDSS, UMR CNRS 5616, Université Joseph Fourier, BP 53, 38041, Grenoble Cedex 9, France.

The generation of free radicals (Fenton chemistry) from various iron citrate complexes has been studied. Spin trapping methods have been used. The results can question concerning the innocence of added citric acid in foods and cold drinks. We concluded that in absence of pathological situation citric acid is probably not dangerous but it may become dangerous in situation of oxidative stress and/or iron overload.

PMID: 17390216 [PubMed - indexed for MEDLINE]


nach oben nach oben

Weiter zu Studie: 1-20 | 21-40 | 41-60 | 61-80 | 81-99