Displaying publications 81 - 100 of 171 in total

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  1. The effects of propranolol on skeletal muscle contraction, lipid peroxidation products and antioxidant activity in experimental hyperthyroidism
    Zaiton Z, Merican Z, Khalid BA, Mohamed JB, Baharom S
    Gen. Pharmacol., 1993 Jan;24(1):195-9.
    PMID: 8482496
    1. The mean levels of lipid peroxidation products, namely conjugated diene and malonaldehyde, were increased in the soleus muscles of hyperthyroid cats, while the mean glutathione peroxidase activity was decreased. No corresponding similar changes were noted in the fast extensor digitorum longus muscles and serum. 2. Propranolol administration prevented the increase in conjugated diene level in the soleus muscles of hyperthyroid cat but not the malonaldehyde level. It also prevented the reduction in glutathione peroxidase activity in the slow oxidative soleus muscles of hyperthyroid cats. 3. Maximal twitch tension, subtetanic tension and maximum tetanic tension of soleus and EDL muscles were reduced in hyperthyroid cats. Propranolol administration for 5 weeks to hyperthyroid cats did not prevent the reduction in tension of contractions of these muscles. 4. It is suggested that lipid peroxidation might not be responsible for the myopathy in hyperthyroidism and propranolol administration does not improve skeletal muscle function in hyperthyroid animals.
    Matched MeSH terms: Glutathione Peroxidase/metabolism
  2. Effect of tocotrienol on the activities of cytosolic glutathione-dependent enzymes in rats treated with 2-acetylaminofluorene
    Shamaan NA, Wan Ngah WZ, Ibrahim R, Jarien Z, Top AG, Abdul Kadir K
    Biochem Pharmacol, 1993 Apr 06;45(7):1517-9.
    PMID: 8471073
    The effect of tocotrienol on the activities of glutathione S-transferases (GSTs), glutathione reductase (GR) and glutathione peroxidase (GPx) in rats given 2-acetylaminofluorene (AAF) was investigated over a 20 week period. Liver and kidney GST and liver GR activities were significantly increased after AAF administration. Kidney GPx activities were significantly affected; activity assayed with cumene hydroperoxide (cu-OOH) was increased but activity assayed with H2O2 was reduced. Supplementation of the diet with tocotrienol in the AAF-treated rats reduced the increase in enzyme activities. Tocotrienol on its own had no effect on the enzyme activities.
    Matched MeSH terms: Glutathione Peroxidase/metabolism
  3. Red cell metabolism and severe neonatal jaundice in West Malaysia
    Lie-Injo LE, Virik HK, Lim PW, Lie AK, Ganesan J
    Acta Haematol., 1977;58(3):152-60.
    PMID: 409030 DOI: 10.1159/000207822
    A study was carried out of 332 babies suffering from severe neonatal jaundice who were admitted to the General Hospital, Kuala Lumpar, Malaysia. Of the 332 neonates, 51 were premature and 281 were full-term babies, 178 (110 Chinese, 58 Malay, 9 Indian and 1 European-Pakistani) had bilirubin levels of 20 mg% or higher, requiring exchange blood transfusion. Of the Chinese neonates, 23 (20.9%) had G6PD deficiency, 9 (8.2%) had Hb Bart's and 2 (1.8%) had an abnormal haemoglobin, one Hb Q and one fetal variant. Among the Malay infants, 10 (17.2%) had G6PD deficiency, 7 (12.1%) had Hb Bart's and 10 (17.2%) had abnormal haemoglobins (four had Hb E trait, one had Hb K and Bart's in addition to Hb E, three had Hb CoSp with Hb Bart's, one had Hb Q and one Hb Tak). One of the nine Indian neonates had G6PD deficiency and one had Hb S trait. The one European-Pakistani baby was a carrier of Hb D Punjab. In addition to G6PD deficiency, abnormal haemoglobins seem to have contributed to the high incidence of severe neonatal jaundice in Malaysia. The mean activities of GP, GR and GR after stimulation with FAD were higher, while the mean activity of PK and mean level of reduced glutathione were lower than in normal cord bloods. The percent increase of GR after FAD stimulation was significantly lower; fewer in this group had increases above 20% than in normal cord blood. The possible significance of the findings is discussed.
    Matched MeSH terms: Glutathione Peroxidase/blood
  4. Fulltext Functional analyses of C.2268dup in thyroid peroxidase gene associated with goitrous congenital hypothyroidism
    Lee CC, Harun F, Jalaludin MY, Lim CY, Ng KL, Mat Junit S
    Biomed Res Int, 2014;2014:370538.
    PMID: 24745015 DOI: 10.1155/2014/370538
    The c.2268dup mutation in thyroid peroxidase (TPO) gene was reported to be a founder mutation in Taiwanese patients with dyshormonogenetic congenital hypothyroidism (CH). The functional impact of the mutation is not well documented. In this study, homozygous c.2268dup mutation was detected in two Malaysian-Chinese sisters with goitrous CH. Normal and alternatively spliced TPO mRNA transcripts were present in thyroid tissues of the two sisters. The abnormal transcript contained 34 nucleotides originating from intron 12. The c.2268dup is predicted to generate a premature termination codon (PTC) at position 757 (p.Glu757X). Instead of restoring the normal reading frame, the alternatively spliced transcript has led to another stop codon at position 740 (p.Asp739ValfsX740). The two PTCs are located at 116 and 201 nucleotides upstream of the exons 13/14 junction fulfilling the requirement for a nonsense-mediated mRNA decay (NMD). Quantitative RT-PCR revealed an abundance of unidentified transcripts believed to be associated with the NMD. TPO enzyme activity was not detected in both patients, even though a faint TPO band of about 80 kD was present. In conclusion, the c.2268dup mutation leads to the formation of normal and alternatively spliced TPO mRNA transcripts with a consequential loss of TPO enzymatic activity in Malaysian-Chinese patients with goitrous CH.
    Matched MeSH terms: Iodide Peroxidase/genetics*
  5. Effect of Tai Chi exercise on DNA damage, antioxidant enzymes, and oxidative stress in middle-age adults
    Goon JA, Aini AH, Musalmah M, Anum MY, Nazaimoon WM, Ngah WZ
    J Phys Act Health, 2009 Jan;6(1):43-54.
    PMID: 19211957
    BACKGROUND: The biochemical mechanisms involving oxidative stress to explain the relationship between exercise and healthy aging are still unclear.

    METHODS: Tai Chi participants and matched sedentary volunteers age 45 and above were enrolled. Glutathione peroxidase (GPx), superoxide dismutase (SOD), and catalase (CAT) activities; levels of DNA damage using the comet assay; and malondialdehyde (MDA) and advanced glycation end products (AGE) were determined at 0, 6, and 12 months.

    RESULTS: Tai Chi subjects had decreased normal and increased mildly damaged DNA with elevated GPx activity after 6 months (n=25). Plasma MDA and AGE concentrations decreased significantly after 12 months (n=15) accompanied by increased SOD activity. This may be attributed to the hormesis effect, whereby mild induction of oxidative stress at the first 6 months of exercise resulted in stimulation of antioxidant defenses. These parameters were unchanged in the sedentary subjects in the first 6 months (n=27) except for elevated SOD activity. After 12 months, the sedentary subjects (n=17) had decreased normal DNA and increased severely damaged DNA with unaltered MDA and AGE levels while SOD and GPx activities were significantly elevated.

    CONCLUSION: Regular Tai Chi exercise stimulated endogenous antioxidant enzymes and reduced oxidative damage markers.

    Matched MeSH terms: Glutathione Peroxidase/blood
  6. Lentinula edodes (Shiitake) mushroom extract protects against hydrogen peroxide induced cytotoxicity in peripheral blood mononuclear cells
    Kuppusamy UR, Chong YL, Mahmood AA, Indran M, Abdullah N, Vikineswary S
    Indian J. Biochem. Biophys., 2009 Apr;46(2):161-5.
    PMID: 19517993
    Lentinula edodes (Berk) Pegler, commonly known as Shiitake mushroom has been used as medicinal food in Asian countries, especially in China and Japan and is believed to possess strong immunomodulatory property. In the present study, the methanolic extract of the fruit bodies of L. edodes was investigated for cytoprotective effect against H2O2-induced cytotoxicity in human peripheral blood mononuclear cells (PBMCs) by measuring the activities of xanthine oxidase (XO) and glutathione peroxidase (GPx) . H2O2 at a concentration of 5 microM caused 50% inhibition of PBMCs viability. The extract improved the PBMC viability and exerted a dose-dependent protection against H2O2-induced cytotoxicity. At 100 microg/ml of extract concentration, the cell viability increased by 60% compared with the PBMCs incubated with H2O2 alone. The extract also inhibited XO activity in PBMC, while showing moderate stimulatory effect on GPx. However, in the presence of H2O2 alone, both the enzyme activities were increased significantly. The GPx activity increased, possibly in response to the increased availability of H2O2 in the cell. When the cells were pretreated with the extract and washed (to remove the extract) prior to the addition of H2O2, the GPx and XO activities as well as the cell viability were comparable to those when incubated with the extract alone. Thus, it is suggested that one of the possible mechanisms via which L. edodes methanolic extract confers protection against H2O2-induced oxidative stress in PBMC is by inhibiting the superoxide-producing XO and increasing GPx activity which could rapidly inactivate H2O2.
    Matched MeSH terms: Glutathione Peroxidase/metabolism
  7. Fulltext Comparison of antioxidant effects of honey, glibenclamide, metformin, and their combinations in the kidneys of streptozotocin-induced diabetic rats
    Erejuwa OO, Sulaiman SA, Wahab MS, Salam SK, Salleh MS, Gurtu S
    Int J Mol Sci, 2011;12(1):829-43.
    PMID: 21340016 DOI: 10.3390/ijms12010829
    Hyperglycemia-induced increase in oxidative stress is implicated in diabetic complications. This study investigated the effect of metformin and/or glibenclamide in combination with honey on antioxidant enzymes and oxidative stress markers in the kidneys of streptozotocin (60 mg/kg; intraperitoneal)-induced diabetic rats. Diabetic rats were randomized into eight groups of five to seven rats and received distilled water (0.5 mL); honey (1.0 g/kg); metformin (100 mg/kg); metformin (100 mg/kg) and honey (1.0 g/kg); glibenclamide (0.6 mg/kg); glibenclamide (0.6 mg/kg) and honey (1.0 g/kg); metformin (100 mg/kg) and glibenclamide (0.6 mg/kg); or metformin (100 mg/kg), glibenclamide (0.6 mg/kg) and honey (1.0 g/kg) orally once daily for four weeks. Malondialdehyde (MDA) levels, glutathione peroxidase (GPx) and superoxide dismutase (SOD) activities were significantly elevated while catalase (CAT) activity, total antioxidant status (TAS), reduced glutathione (GSH), and GSH:oxidized glutathione (GSSG) ratio was significantly reduced in the diabetic kidneys. CAT, glutathione reductase (GR), TAS, and GSH remained significantly reduced in the diabetic rats treated with metformin and/or glibenclamide. In contrast, metformin or glibenclamide combined with honey significantly increased CAT, GR, TAS, and GSH. These results suggest that combination of honey with metformin or glibenclamide might offer additional antioxidant effect to these drugs. This might reduce oxidative stress-mediated damage in diabetic kidneys.
    Matched MeSH terms: Glutathione Peroxidase/metabolism
  8. Comparison of oxidative damage in Malaysian end-stage renal disease patients with or without non-insulin-dependent diabetes mellitus
    Kuppusamy UR, Indran M, Ahmad T, Wong SW, Tan SY, Mahmood AA
    Clin Chim Acta, 2005 Jan;351(1-2):197-201.
    PMID: 15563890 DOI: 10.1016/j.cccn.2004.09.014
    BACKGROUND: Comparisons of oxidative indices and total antioxidant status between end-stage renal disease (ESRD) patients with or without diabetes is scant, especially in the Asian population.
    METHOD: The assays were carried out according to known established protocols.
    RESULT: The present study showed that ESRD patients with or without non-insulin-dependent diabetes mellitus (NIDDM) did not have any significant differences in antioxidant enzyme activities, advanced glycated end products (AGE), advanced oxidized protein products (AOPP) and ferric reducing ability of plasma (FRAP), indicating that hyperglycemia does not exacerbate oxidative damage in ESRD. The regulation of catalase and glutathione peroxidase is also altered in ESRD. Elevated FRAP was observed in both ESRD groups (with and without NIDDM). The dialysis process did not alter the antioxidant enzyme activities but decreased AGEs and FRAP and increased AOPP levels.
    CONCLUSION: Oxidative stress is present in ESRD but this is not significantly exacerbated by hyperglycemia. The contribution of components in the pathology of renal failure towards oxidative stress exceeds that of hyperglycemia.
    Matched MeSH terms: Glutathione Peroxidase/metabolism
  9. Antioxidant enzyme activities of human peripheral blood mononuclear cells exposed to trace elements
    Kuppusamy UR, Dharmani M, Kanthimathi MS, Indran M
    Biol Trace Elem Res, 2005 Jul;106(1):29-40.
    PMID: 16037608
    The trace elements copper, zinc, and selenium are important immune modulators and essential cofactors of the antioxidant enzymes. In the present study, the proliferative effect of human peripheral mononuclear cells (PBMCs) that have been exposed to copper, zinc, and selenium and the corresponding activities of antioxidant enzymes, namely superoxide dismutase (SOD), glutathione peroxidase (GPx), and catalase, were determined. Zinc and copper stimulated the PBMC proliferation in a dose-dependent manner within the dose range 25-200 micromol/L. SOD and GPx activities in PBMCs exposed to zinc were inhibited, whereas catalase activity was unaffected. All the three antioxidant enzymes in the cells exposed to copper were inhibited. Selenium exerted more potent inhibition of the cell proliferation while causing stimulation of the antioxidant enzymes at the lowest dose (25 micromol/L) than at the highest dose (200 micromol/L) tested. A significant negative correlation was observed between proliferation and antioxidant enzyme (SOD and GPx) activities in trace-element-exposed PBMC. The present findings substantiate the importance of trace elements as immune modulators and the involvement of enzymatic antioxidant system in the immune cell regulation.
    Matched MeSH terms: Glutathione Peroxidase/metabolism
  10. Baccaurea angulata fruit inhibits lipid peroxidation and induces the increase in antioxidant enzyme activities
    Mikail MA, Ahmed IA, Ibrahim M, Hazali N, Abdul Rasad MS, Abdul Ghani R, et al.
    Eur J Nutr, 2016 Jun;55(4):1435-44.
    PMID: 26091909 DOI: 10.1007/s00394-015-0961-7
    PURPOSE: The consequence of the increased demand due to the population expansion has put tremendous pressure on the natural supply of fruits. Hence, there is an unprecedented growing interest in the exploration of the potentials of underutilized fruits as alternatives to the commercially available fruits. Baccaurea angulata is an underutilized fruit widely distributed in Borneo Island of Malaysia. The present study was conducted to investigate the effects of B. angulata whole fruit (WF), skin (SK) and pulp (PL) juices on malondialdehyde (MDA) levels and antioxidant enzymes in rabbits fed high-cholesterol diet.

    METHODS: Thirty-six male rabbits of New Zealand strain were randomly assigned to six groups. Rabbits were fed either a standard pellet (group NC) or a high-cholesterol diet (groups HC, PC, WF, SK and PL). Groups WF, SK and PL were also given 1 ml/kg/day B. angulata WF, SK and PL juices, respectively.

    RESULTS: Baccaurea angulata had high antioxidant activities. The administration of the various juices significantly reduced (p 

    Matched MeSH terms: Glutathione Peroxidase/blood
  11. Pharmacokinetics of the Sri Lankan hump-nosed pit viper (Hypnale hypnale) venom following intravenous and intramuscular injections of the venom into rabbits
    Tan CH, Sim SM, Gnanathasan CA, Fung SY, Tan NH
    Toxicon, 2014 Mar;79:37-44.
    PMID: 24412778 DOI: 10.1016/j.toxicon.2013.12.011
    The knowledge of venom pharmacokinetics is essential to improve the understanding of envenomation pathophysiology. Using a double-sandwich ELISA, this study investigated the pharmacokinetics of the venom of hump-nosed pit viper (Hypnale hypnale) following intravenous and intramuscular injections into rabbits. The pharmacokinetics of the venom injected intravenously fitted a three-compartment model. There is a rapid (t1/2π = 0.4 h) and a slow (t1/2α = 0.8 h) distribution phase, followed by a long elimination phase (t1/2β = 19.3 h) with a systemic clearance of 6.8 mL h(-1) kg(-1), consistent with the prolonged abnormal hemostasis reported in H. hypnale envenomation. On intramuscular route, multiple peak concentrations observed in the beginning implied a more complex venom absorption and/or distribution pattern. The terminal half-life, volume of distribution by area and systemic clearance of the venom injected intramuscularly were nevertheless not significantly different (p > 0.05) from that of the venom injected intravenously. The intramuscular bioavailability was exceptionally low (Fi.m. = 4%), accountable for the highly varied median lethal doses between intravenous and intramuscular envenomations in animals. The findings indicate that the intramuscular route of administration does not significantly alter the pharmacokinetics of H. hypnale venom although it significantly reduces the systemic bioavailability of the venom.
    Matched MeSH terms: Horseradish Peroxidase/blood
  12. Fulltext Manuka honey protects middle-aged rats from oxidative damage
    Jubri Z, Rahim NB, Aan GJ
    Clinics (Sao Paulo), 2013 Nov;68(11):1446-54.
    PMID: 24270958 DOI: 10.6061/clinics/2013(11)11
    This study aimed to determine the effect of manuka honey on the oxidative status of middle-aged rats.
    Matched MeSH terms: Glutathione Peroxidase/analysis
  13. Effect of melatonin supplementation and cross-fostering on renal glutathione system and development of hypertension in spontaneously hypertensive rats
    Siew-Keah L, Sundaram A, Sirajudeen KN, Zakaria R, Singh HJ
    J Physiol Biochem, 2014 Mar;70(1):73-9.
    PMID: 23975651 DOI: 10.1007/s13105-013-0282-3
    Antenatal and postnatal environments are hypothesised to influence the development of hypertension. This study investigates the synergistic effect of cross-fostering and melatonin supplementation on the development of hypertension and renal glutathione system in spontaneously hypertensive rats (SHR). In one experiment, 1-day-old male SHR pups were fostered to either SHR (shr-SHR) or Wistar-Kyoto rats, (shr-WKY). In a concurrent experiment, SHR dams were given melatonin in drinking water (10 mg/kg body weight) from day 1 of pregnancy. Immediately following delivery, 1-day-old male pups were fostered either to SHR (Mel-shr-SHR) or WKY (Mel-shr-WKY) dams receiving melatonin supplementation until weaning on day 21. Upon weaning, melatonin supplementation was continued to these pups until the age of 16 weeks. Systolic blood pressures (SBP) were recorded at the age of 4, 6, 8, 12 and 16 weeks. Renal antioxidant activities were measured. Mean SBP of shr-WKY, Mel-shr-SHR and Mel-shr-WKY was significantly lower than that in shr-SHR until the age of 8 weeks. At 12 and 16 weeks of age, mean SBP of Mel-shr-WKY was lower than those in non-treated shr-SHR and shr-WKY pups but was not significantly different from that in Mel-shr-SHR. Renal glutathione peroxidase (GPx) and glutathione S-transferase (GST) activities were significantly higher in Mel-shr-SHR and Mel-shr-WKY at 16 weeks of age. It appears that combination of cross-fostering and melatonin supplementation exerts no synergistic effect on delaying the rise in blood pressure in SHR. The elevated GPx and GST activities are likely to be due to the effect of melatonin supplementation.
    Matched MeSH terms: Glutathione Peroxidase/metabolism
  14. Fulltext Comparative effect of Piper betle, Chlorella vulgaris and tocotrienol-rich fraction on antioxidant enzymes activity in cellular ageing of human diploid fibroblasts
    Makpol S, Yeoh TW, Ruslam FA, Arifin KT, Yusof YA
    BMC Complement Altern Med, 2013;13:210.
    PMID: 23948056 DOI: 10.1186/1472-6882-13-210
    Human diploid fibroblasts (HDFs) undergo a limited number of cellular divisions in culture and progressively reach a state of irreversible growth arrest, a process termed cellular ageing. Even though beneficial effects of Piper betle, Chlorella vulgaris and tocotrienol-rich fraction (TRF) have been reported, ongoing studies in relation to ageing is of interest to determine possible protective effects that may reverse the effect of ageing. The aim of this study was to evaluate the effect of P. betle, C. vulgaris and TRF in preventing cellular ageing of HDFs by determining the activity of antioxidant enzymes viz.; catalase, superoxide dismutase (SOD) and glutathione peroxidase.
    Matched MeSH terms: Glutathione Peroxidase/metabolism
  15. Association of oxidative stress and memory performance in postmenopausal women receiving estrogen-progestin therapy
    Shafin N, Zakaria R, Hussain NH, Othman Z
    Menopause, 2013 Jun;20(6):661-6.
    PMID: 23715378 DOI: 10.1097/GME.0b013e31827758c6
    The aim of this study was to examine the association between changes in blood oxidative stress level/activity and changes in memory performance among postmenopausal women.
    Matched MeSH terms: Glutathione Peroxidase/blood
  16. Fulltext A plasmid-encoded peptide from Staphylococcus aureus induces anti-myeloperoxidase nephritogenic autoimmunity
    Ooi JD, Jiang JH, Eggenhuizen PJ, Chua LL, van Timmeren M, Loh KL, et al.
    Nat Commun, 2019 07 29;10(1):3392.
    PMID: 31358739 DOI: 10.1038/s41467-019-11255-0
    Autoreactivity to myeloperoxidase (MPO) causes anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV), with rapidly progressive glomerulonephritis. Here, we show that a Staphylococcus aureus peptide, homologous to an immunodominant MPO T-cell epitope (MPO409-428), can induce anti-MPO autoimmunity. The peptide (6PGD391-410) is part of a plasmid-encoded 6-phosphogluconate dehydrogenase found in some S. aureus strains. It induces anti-MPO T-cell autoimmunity and MPO-ANCA in mice, whereas related sequences do not. Mice immunized with 6PGD391-410, or with S. aureus containing a plasmid expressing 6PGD391-410, develop glomerulonephritis when MPO is deposited in glomeruli. The peptide induces anti-MPO autoreactivity in the context of three MHC class II allomorphs. Furthermore, we show that 6PGD391-410 is immunogenic in humans, as healthy human and AAV patient sera contain anti-6PGD and anti-6PGD391-410 antibodies. Therefore, our results support the idea that bacterial plasmids might have a function in autoimmune disease.
    Matched MeSH terms: Peroxidase/immunology*; Peroxidase/metabolism
  17. The effect of zinc supplementation on antioxidant and lipid peroxidation status during Brachiaria decumbens intoxication in sheep
    Zhang SS, Noordin MM, Rahman SO, Haron MJ
    Vet Hum Toxicol, 2001 Apr;43(2):83-7.
    PMID: 11308125
    An attempt was made to clarify the association between zinc (Zn) and antioxidants due to Zn supplementation on lipid peroxidation occurring during Brachiaria decumbens intoxication. The concentration of Zn, copper, malondialdehyde (MDA), superoxide dismutase (SOD), and gluthathione peroxidase (GSH-Px) were determined in tissues. There was a gradual increment in the concentration of Zn and MDA in serum and hepatocytic SOD in groups given Zn + B decumbens. A decline in erythrocytic GSH-Px and SOD, and lower concentration of reduced glutathione in hepatocyte cytosols were also detected in these sheep. It is highly suggestive that Zn supplementation may depress antioxidant status and enhance lipid peroxidation during B decumbens intoxication.
    Matched MeSH terms: Glutathione Peroxidase/blood; Glutathione Peroxidase/drug effects
  18. Receptor for advanced glycation end-product (RAGE) gene polymorphism 2245G/A is associated with pro-inflammatory, oxidative-glycation markers and sRAGE in diabetic retinopathy
    Ng ZX, Kuppusamy UR, Iqbal T, Chua KH
    Gene, 2013 Jun 1;521(2):227-33.
    PMID: 23545311 DOI: 10.1016/j.gene.2013.03.062
    Receptor for advanced glycation end-product (RAGE) gene polymorphism 2245G/A is associated with diabetic retinopathy (DR). However, the mechanism on how it affects the disease development is still unclear.
    Matched MeSH terms: Glutathione Peroxidase/genetics; Glutathione Peroxidase/metabolism
  19. Oxidative damage and antioxidant status in patients with cervical intraepithelial neoplasia and carcinoma of the cervix
    Looi ML, Mohd Dali AZ, Md Ali SA, Wan Ngah WZ, Mohd Yusof YA
    Eur J Cancer Prev, 2008 Nov;17(6):555-60.
    PMID: 18941377 DOI: 10.1097/CEJ.0b013e328305a10b
    Free radicals that induced lipid peroxidation and DNA damage have been implicated in many diseases including cancer. Cellular antioxidant defense plays an important role in neoplastic disease to counteract oxidative damage. This study aims to investigate the status of oxidative damage by measuring plasma malondialdehyde (MDA) level and urinary 8-hydroxydeoxyguanosine (8-OHdG), and the level of antioxidant enzymes superoxide dismutase, glutathione peroxidase, and catalase in patients with cervical intraepithelial neoplasia (CIN) and squamous cell carcinoma (SCC) of the cervix. Urinary 8-OHdG was measured by an enzyme-linked immunosorbent assay kit. MDA and antioxidant enzyme activities were determined by high-performance liquid chromatography and spectrophotometry, respectively. Eighty patients with CIN and SCC of the cervix were recruited and compared with normal controls. Urinary 8-OHdG/creatinine ratio did not show any significant changes in any disease status studied as compared with controls (P=0.803). Plasma MDA was found to be increased in CIN and SCC patients when compared with controls (P=0.002). Glutathione peroxidase activity was increased (P=0.0001) whereas superoxide dismutase and catalase activity was decreased (P=0.019 and 0.0001, respectively) in both CIN and SCC patients when compared with controls. Urinary 8-OHdG may not be a good marker for enhanced oxidative stress in cervical cancer. Oxidative damage as demonstrated by the level of MDA is markedly increased in CIN and SCC patients with changes of enzymatic antioxidants observed.
    Matched MeSH terms: Glutathione Peroxidase/blood; Glutathione Peroxidase/metabolism
  20. Nigella sativa thymoquinone-rich fraction greatly improves plasma antioxidant capacity and expression of antioxidant genes in hypercholesterolemic rats
    Ismail M, Al-Naqeep G, Chan KW
    Free Radic Biol Med, 2010 Mar 01;48(5):664-72.
    PMID: 20005291 DOI: 10.1016/j.freeradbiomed.2009.12.002
    The antioxidant activities of the thymoquinone-rich fraction (TQRF) extracted from Nigella sativa and its bioactive compound, thymoquinone (TQ), in rats with induced hypercholesterolemia were investigated. Rats were fed a semipurified diet supplemented with 1% (w/w) cholesterol and were treated with TQRF and TQ at dosages ranging from 0.5 to 1.5 g/kg and 20 to 100 mg/kg body wt, respectively, for 8 weeks. The hydroxyl radical (OH(.))-scavenging activity of plasma samples collected from experimental rats was measured by electron spin resonance. The GenomeLab Genetic Analysis System was used to study the molecular mechanism that mediates the antioxidative properties of TQRF and TQ. Plasma total cholesterol and low-density-lipoprotein cholesterol levels were significantly decreased in the TQRF- and TQ-treated rats compared to untreated rats. Feeding rats a 1% cholesterol diet for 8 weeks resulted in a significant decrease in plasma antioxidant capacity, as measured by the capacity to scavenge hydroxyl radicals. However, rats treated with TQRF and TQ at various doses showed significant inhibitory activity toward the formation of OH(.) compared to untreated rats. Upon examination of liver RNA expression levels, treatment with TQRF and TQ caused the up-regulation of the superoxide dismutase 1 (SOD1), catalase, and glutathione peroxidase 2 (GPX) genes compared to untreated rats (P<0.05). In support of this, liver antioxidant enzyme levels, including SOD1 and GPX, were also apparently increased in the TQRF- and TQ-treated rats compared to untreated rats (P<0.05). In conclusion, TQRF and TQ effectively improved the plasma and liver antioxidant capacity and enhanced the expression of liver antioxidant genes of hypercholesterolemic rats.
    Matched MeSH terms: Glutathione Peroxidase/biosynthesis; Glutathione Peroxidase/genetics
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