Displaying publications 41 - 60 of 292 in total

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  1. Mohd Esa N, Abdul Kadir KK, Amom Z, Azlan A
    Food Chem, 2013 Nov 15;141(2):1306-12.
    PMID: 23790918 DOI: 10.1016/j.foodchem.2013.03.086
    Antioxidant activity of different rice extract and the effect on the levels of antioxidant enzyme activity, superoxide dismutase (SOD) and glutathione peroxidase (GPx), vitamin E, lipid peroxidation and liver enzymes in hyperlipidaemia rabbits were investigated. Germinated brown rice (GBR) has the highest antioxidant activity compared to white rice (WR) and brown rice (BR). All rice grains increased the activity of SOD and GPx. However, vitamin E levels increased only in the groups that received the BR and GBR diets. The reduction of lipid peroxidation levels and activity of hepatic enzymes (alanine transferase, ALT and aspartate transaminase, AST) were only significantly observed in the GBR group. In conclusion, GBR supplementation has the greatest impact on increasing antioxidant enzyme activity and vitamin E level and on reducing lipid peroxidation in hypercholesterolaemia rabbit, thereby preventing the formation of atherosclerotic plaques. Furthermore, GBR diet can also reduce the level of hepatic enzymes.
    Matched MeSH terms: Glutathione Peroxidase/metabolism
  2. Ahmed Atia, Nadia Salem Alrawaiq, Azman Abdullah
    Sains Malaysiana, 2018;47:2799-2809.
    Glutathione S-transferase isoenzymes (GSTs) catalyze the conjugation reaction between glutathione and electrophilic
    compounds. GSTs are involved in the detoxification of toxic and carcinogenic compounds, thus protecting the body from
    toxic injuries. Tocotrienols are part of the vitamin E family and is believed to possess potent antioxidant activity. The
    objective of this study was to determine the effect of increasing doses of tocotrienol rich fraction (TRF) supplementation
    on liver GSTs gene and protein expression. A total of 30 male ICR white mice were divided into five groups (n=6 for each
    group) and given treatment for 14 days through oral supplementation. Groups were divided as follows: - three groups
    administered with TRF at doses of 200, 500 and 1000 mg/kg, respectively, a positive control group administered with 100
    mg/kg butylated hydroxyanisole (BHA) and a control group administered with only the vehicle (corn oil). At day 15, the
    mice were sacrificed and their livers isolated. Total RNA was extracted from the liver and quantitative real-time polymerase
    chain reaction (qPCR) assays were performed to analyze GSTs gene expression. Total liver protein was also extracted
    and the protein expression of GSTs was determined by Western blotting. The results showed that TRF oral supplementation
    caused a significant dose-dependent increase in liver GST isoenzymes gene and protein expression, compared to controls.
    In conclusion, TRF oral supplementation for 14 days resulted in increased gene and protein expression of GST isoenzymes
    in mice liver dose-dependently, with the highest expression seen in mice treated with 1000 mg/kg TRF.
    Matched MeSH terms: Glutathione; Glutathione Transferase
  3. Samie N, Muniandy S, Kanthimathi MS, Haerian BS, Azudin RE
    Sci Rep, 2016 Apr 13;6:24172.
    PMID: 27072064 DOI: 10.1038/srep24172
    The current study evaluates the cytotoxic mechanism of a novel piperazine derivate designated as PCC against human liver cancer cells. In this context, human liver cancer cell lines, SNU-475 and 243, human monocyte/macrophage cell line, CRL-9855, and human B lymphocyte cell line, CCL-156, were used to determine the IC50 of PCC using the standard MTT assay. PCC displayed a strong suppressive effect on SNU-475 and SNU-423 cells with an IC50 value of 6.98 ± 0.11 μg/ml and 7.76 ± 0.45 μg/ml respectively, after 24 h of treatment. Significant dipping in the mitochondrial membrane potential and elevation in the released of cytochrome c from the mitochondria indicated the induction of the intrinsic apoptosis pathway by PCC. Activation of this pathway was further evidenced by significant activation of caspase 3/7 and 9. PCC was also shown to activate the extrinsic pathways of apoptosis via activation of caspase-8 which is linked to the suppression of NF-ƙB translocation to the nucleus. Cell cycle arrest in the G1 phase was confirmed by flow cytometry and up-regulation of glutathione reductase expression was quantified by qPCR. This study suggests that PCC is a simultaneous inducer of intrinsic and extrinsic pathways of apoptosis in liver cancer cell lines.
    Matched MeSH terms: Glutathione Reductase
  4. 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
  5. Azeem E, Gillani SW, Siddiqui A, Mian RI, Poh V, Sulaiman SA, et al.
    Curr Diabetes Rev, 2016;12(3):279-84.
    PMID: 25989845 DOI: 10.2174/1573399811666150520094631
    Background/aim: Diabetes mellitus (DM) is a considerable systemic metabolic disorder to exhibit various metabolic and cardiovascular disorders, mainly hyperglycemia. Our study aims to evaluate oxidative stress markers in DM patients and to determine the clinical correlates affecting the investigational parameters.

    Methodology: To evaluate oxidative stress, the following parameters were included: tri-glycerides(TG), total cholesterol, low density lipoprotein cholesterol(LDL), oxidized LDL cholesterol(Ox LDL), superoxide dismutase(SOD), glutathione peroxidase(GSH-Px) and plasminogen activator inhibitor(PAI) which were measured at single observation point. Patient clinical and demographic data were taken from registered medication profiles from the Outpatient Department.

    Results: The diabetic subjects have significantly high measured values of endocrine(p<0.01), metabolic(p<0.01) and antioxidant parameters(p<0.05), and have significant higher values of TG(3.69±1.27 vs 1.79±0.84 mmol/L, p< 0.01), Ox LDL(85.37±19.1 vs 77.11±26.64 mmol/L, p<0.05) and SOD enzyme activity(918.78 ± 145.39 vs 880.08±149.52 U/g Hb, p<0.05) compared to the controls. A significant negative correlation was found between Ox LDL and HbA1c(r = -0.6782, p < 0.001) among diabetic subjects.

    Conclusion: Elevated Ox-LDL, SOD and GSH-Px are associated with the diabetic patients. However, oxidative stress threshold values also showed high oxidative activity markers among controls. Clinical variables showed predictive information on oxidative activity among diabetes patients.
    Matched MeSH terms: Glutathione Peroxidase
  6. Lie-Injo LE, Ng T, Balakrishnan S
    Clin Chim Acta, 1974 Jan 19;50(1):77-83.
    PMID: 4856203 DOI: 10.1016/0009-8981(74)90079-5
    Matched MeSH terms: Glutathione; Glutathione Reductase/blood
  7. Nagamma T, Bhutia RD, Pokharel DR, Yadav S, Baxi J
    Asian Pac J Cancer Prev, 2012;13(7):3513-7.
    PMID: 22994787
    AIM: The present study assess the effect of consumption of alcohol on oxidative stress and antioxidant status in patients suffering from different types of cancer.

    METHODS: This hospital based case control study conducted in the Western part of Nepal covered a total of 93 cancer patients with or without alcohol intake and smoking habits, along with 94 age, sex and habit-matched individuals serving as controls. Plasma thiobarbituric acid reacting substances (TBARS), total antioxidant activity (TAA), vitamin C, α-tocopherol and erythrocyte reduced glutathione (GSH) were estimated and compared.

    RESULTS: The TBARS level was found to be significantly higher (p≤0.001) in all types of cancer patients when compared to controls, being aggravated in alcoholics with a smoking habit. No statistical significance (p≥0.05) was observed in the level of vitamin C and α-tocopherol. GSH and TAA level were significantly decreased (p≤0.001) in all the groups except those who consumed both branded as well as homemade alcohol and non-alcoholics without smoking habit.

    CONCLUSION: Alcohol, irrespective of its commercial brand, increases oxidative stress in all types of cancer patients. This is even higher when alcohol intake is combined with a smoking habit. Decreased TAA and GSH are major risk factors for cancer development.

    Matched MeSH terms: Glutathione/blood
  8. Sujitha V, Murugan K, Dinesh D, Pandiyan A, Aruliah R, Hwang JS, et al.
    Aquat Toxicol, 2017 Jul;188:100-108.
    PMID: 28482328 DOI: 10.1016/j.aquatox.2017.04.015
    Currently, nano-formulated mosquito larvicides have been widely proposed to control young instars of malaria vector populations. However, the fate of nanoparticles in the aquatic environment is scarcely known, with special reference to the impact of nanoparticles on enzymatic activity of non-target aquatic invertebrates. In this study, we synthesized CdS nanoparticles using a green protocol relying on the cheap extract of Valoniopsis pachynema algae. CdS nanoparticles showed high toxicity on young instars of the malaria vectors Anopheles stephensi and A. sundaicus. The antimalarial activity of the nano-synthesized product against chloroquine-resistant (CQ-r) Plasmodium falciparum parasites was investigated. From a non-target perspective, we focused on the impact of this novel nano-pesticide on antioxidant enzymes acetylcholinesterase (AChE) and glutathione S-transferase (GST) activities of the mud crab Scylla serrata. The characterization of nanomaterials was carried out by UV-vis and FTIR spectroscopy, as well as SEM and XRD analyses. In mosquitocidal assays, LC50 of V. pachynema-synthesized CdS nanoparticles on A. stephensi ranged from 16.856 (larva I), to 30.301μg/ml (pupa), while for An. sundaicus they ranged from 13.584 to 22.496μg/ml. The antiplasmodial activity of V. pachynema extract and CdS nanoparticles was evaluated against CQ-r and CQ-sensitive (CQ-s) strains of Plasmodium falciparum. IC50 of V. pachynema extract was 58.1μg/ml (CQ-s) and 71.46μg/ml (CQ-r), while nano-CdS IC50 was 76.14μg/ml (CQ-s) and 89.21μg/ml (CQ-r). In enzymatic assays, S. serrata crabs were exposed to sub-lethal concentrations, i.e. 4, 6 and 8μg/ml of CdS nanoparticles, assessing changes in GST and AChE activity after 16days. We observed significantly higher activity of GST, if compared to the control, during the whole experiment period. In addition, a single treatment with CdS nanoparticles led to a significant decrease in AChE activity over time. The toxicity of CdS nanoparticles and Cd ions in aqueous solution was also assessed in mud crabs, showing higher toxicity of aqueous Cd ions if compared to nano-CdS. Overall, our results underlined the efficacy of green-synthesized CdS nanoparticles in malaria vector control, outlining also significant impacts on the enzymatic activity of non-target aquatic organisms, with special reference to mud crabs.
    Matched MeSH terms: Glutathione Transferase/metabolism
  9. Abd Rashid N, Hussan F, Hamid A, Adib Ridzuan NR, Halim SASA, Abdul Jalil NA, et al.
    EXCLI J, 2020;19:1246-1265.
    PMID: 33122975 DOI: 10.17179/excli2020-2355
    Oxidative stress, inflammation and apoptosis are thought as primary mediators of cisplatin-induced hepatotoxicity. The objective of this study was to determine the protective effect of Polygonum minus essential oil in cisplatin-induced hepatotoxicity. A total of forty-two male rats were randomly divided into seven groups: control, cisplatin, β-caryophyllene 150 mg/kg (BCP), PmEO 100 mg/kg + cisplatin (PmEO100CP), PmEO 200 mg/kg + cisplatin (PmEO200CP), PmEO 400 mg/kg + cisplatin (PmEO400CP) and PmEO 400 mg/kg (PmEO400). Rats in the BCP, PmEO100CP, PmEO200CP, PmEO400CP and PmEO400 group received respective treatment orally for 14 consecutive days prior to cisplatin injection. All animals except for those in the control group and PmEO400 were administered with a single dose of cisplatin (10 mg/kg) intraperitoneally on day 15 and all animals were sacrificed on day 18. PmEO100CP pretreatment protected against cisplatin-induced hepatotoxicity by decreasing CYP2E1 and indicators of oxidative stress including malondialdehyde, 8-OHdG and protein carbonyl which was accompanied by increased antioxidant status (glutathione, glutathione peroxidase, superoxide dismutase and catalase) as compared to cisplatin group. PmEO100CP pretreatment also modulated changes in liver inflammatory markers (TNF-α, IL-1α, IL-1β, IL-6 and IL-10). PmEO100CP administration also notably reduced cisplatin-induced apoptosis significantly as compared to cisplatin group. In conclusion, our results suggested that P. minus essential oil at a dose of 100 mg/kg may protect against cisplatin-induced hepatotoxicity possibly via inhibition of oxidative stress, inflammation and apoptosis.
    Matched MeSH terms: Glutathione; Glutathione Peroxidase
  10. Latif A, Hussain K, Shehzadi N, Islam M, Khan MT, Anwar R, et al.
    Pharm Biol, 2017 Dec;55(1):547-553.
    PMID: 27951746
    CONTEXT: Kanji, a liquid preparation of roots of Daucus carota L. ssp. sativus (Hoffm.) Arcang. var. vavilovii Mazk. (Apiaceae), may inhibit glutathione sulfotransferase (GST) activity due to ferulic acid content.

    OBJECTIVES: GST inhibition activity and characterization of Kanji and methanol extract of D. carota roots, and oral absorption pattern of ferulic acid from Kanji in rats.

    MATERIALS AND METHODS: GST inhibition activity of Kanji and methanol extract of D. carota roots in concentration range 0.001-100.00 mg/mL was determined using Sprague Dawley rat liver cytosolic fraction. Methanol extract upon column chromatography gave ferulic acid, which was used to characterize Kanji and determine its oral absorption pattern in Wistar rats.

    RESULTS: The GST inhibition activity of Kanji (100.00 μg/mL), methanol extract of D. carota roots (100.00 μg/mL) and tannic acid (10.00 μg/mL, positive control) was found to be 0.162 ± 0.016, 0.106 ± 0.013 and 0.073 ± 0.004 μM/min/mg, respectively. Different Kanji samples and methanol extract contained ferulic acid (0.222-0.316 mg/g) and 0.77 mg/g, respectively. Ferulic acid did not appear in plasma after oral administration of Kanji.

    DISCUSSION: Kanji having solid contents 80.0 μg/mL, equivalent to 0.0025 μg/mL ferulic acid, does not inhibit the activity of GST. The oral administration of Kanji, in human equivalent dose (528 mg/kg, 16.67 μg ferulic acid), to rats indicated poor absorption of ferulic acid.

    CONCLUSION: Kanji having solid contents 14-36 mg/mL does not inhibit GST activity, hence may not interfere with drugs that are the substrates of GST, if taken concomitantly.

    Matched MeSH terms: Glutathione Transferase/antagonists & inhibitors*; Glutathione Transferase/metabolism
  11. Haleagrahara N, Julian V, Chakravarthi S
    Cardiovasc Toxicol, 2011 Dec;11(4):373-81.
    PMID: 21796404 DOI: 10.1007/s12012-011-9132-0
    This study investigated the cardioprotective effect of N-acetylcysteine (NAC) on isoproterenol (ISO)-induced cardiotoxicity in rats. Male Sprague-Dawley rats were divided into control, NAC alone (100 mg/kg BW orally for 14 days), ISO-control (85 mg/kg BW), and ISO with NAC (for 14 days). Serum creatine kinase-MB and Lactate dehydrogenase were measured. From the heart homogenate lipid hydroperoxides (LPO), superoxide dismutase (SOD), total glutathione (GSH), and 8-isoprostane (IP) were measured. Histopathological examination of the heart was also carried out. There was a significant increase (P 
    Matched MeSH terms: Glutathione/metabolism
  12. Haleagrahara N, Varkkey J, Chakravarthi S
    Int J Mol Sci, 2011;12(10):7100-13.
    PMID: 22072938 DOI: 10.3390/ijms12107100
    The aim of the present study was to look into the possible protective effects of glycyrrhizic acid (GA) against isoproterenol-induced acute myocardial infarction in Sprague-Dawley rats. The effect of three doses of glycyrrhizic acid in response to isoproterenol (ISO)-induced changes in 8-isoprostane, lipid hydroperoxides, super oxide dismutase and total glutathione were evaluated. Male Sprague-Dawley rats were divided into control, ISO-control, glycyrrhizic acid alone (in three doses-5, 10 and 20 mg/kg BW) and ISO with glycyrrhizic acid (in three doses) groups. ISO was administered at 85 mg/kg BW at two consecutive days and glycyrrhizic acid was administered intraperitoneally for 14 days. There was a significant increase in 8-isoprostane (IP) and lipid hydroperoxide (LPO) level in ISO-control group. A significant decrease in total superoxide dismutase (SOD) and total glutathione (GSH) was seen with ISO-induced acute myocardial infarction. Treatment with GA significantly increased SOD and GSH levels and decreased myocardial LPO and IP levels. Histopathologically, severe myocardial necrosis and nuclear pyknosis and hypertrophy were seen in ISO-control group, which was significantly reduced with GA treatment. Gycyrrhizic acid treatment proved to be effective against isoproterenol-induced acute myocardial infarction in rats and GA acts as a powerful antioxidant and reduces the myocardial lipid hydroperoxide and 8-isoprostane level.
    Matched MeSH terms: Glutathione/metabolism
  13. 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
  14. Alfarisi, H. A. H., Ibrahim, M.,, Mohamed, Z. B. H., Hamdan, A. H., Che Mohamad, C. A.
    MyJurnal
    Oxidative stress and reactive oxygen species (ROS) constitute a major pathogenic mechanism
    for the development of atherosclerosis. In the present work, the antioxidant potential of
    Trihoney was investigated in hypercholesterolaemic rabbits. Thirty-six male New Zealand
    white (NZW) rabbits were grouped into: normal diet (C), normal diet with 0.6 g/kg/day of
    Trihoney (C+H), 1% cholesterol diet (HCD), 1% cholesterol diet with 0.3 g/kg/day of
    Trihoney (HCD+H1
    ), 1% cholesterol diet with 0.6 g/kg/day of Trihoney (HCD+H2
    ), and 1%
    cholesterol diet with 2 mg/kg/day of atorvastatin (HCD+At.). Animals were sacrificed following 12 weeks of treatment, and their serum was analysed for oxidised-low density lipoprotein
    (Ox-LDL). Serum and aortic tissue homogenate were assayed for superoxide dismutase
    (SOD), glutathione peroxidase (GPx), and malondialdehyde (MDA). Hypercholesterolemia
    caused a significant (p < 0.05) elevation in serum Ox-LDL and a significant (p < 0.05) reduction of antioxidant enzyme activities in serum of the HCD group. Trihoney induced a significant (p < 0.05) increase in antioxidant enzyme activities in serum as compared to the HCD
    group. The high cholesterol diet suppressed both antioxidant enzymes in aortic homogenate.
    Trihoney significantly (p < 0.05) enhanced both antioxidant enzymes in aortic homogenate.
    Hypercholesterolemia induced a significant (p < 0.05) elevation of serum lipid peroxidation in
    the HCD group. Trihoney caused a significant (p < 0.05) reduction of lipid peroxidation in
    aortic homogenate. These results demonstrated that Trihoney has the potential to ameliorate
    oxidative stress systemically, as well as locally in the atherosclerotic aorta.
    Matched MeSH terms: Glutathione Peroxidase
  15. Sowndhararajan K, Hong S, Jhoo JW, Kim S, Chin NL
    Saudi J Biol Sci, 2015 Nov;22(6):685-91.
    PMID: 26586994 DOI: 10.1016/j.sjbs.2015.03.010
    Acacia species are multipurpose trees, widely used in the traditional systems of medicine to treat various ailments. The major objective of the present study was to determine the gene expression of enzymatic antioxidants by acetone extract from the stem bark of three Acacia species (Acacia dealbata, Acacia ferruginea and Acacia leucophloea) in hydrogen peroxide (H2O2)-induced human hepatoma (HepG2) cells. The expression of antioxidant enzymes such as superoxide dismutase containing copper-zinc (CuZnSOD)/manganese (MnSOD), catalase (CAT) and glutathione peroxidase (GPx) in HepG2 cells was evaluated by real-time PCR. The results of antioxidant enzyme expression in real-time PCR study revealed that the H2O2 (200 μM) challenged HepG2 cells reduced the expression of enzymes such as SOD, GPx and CAT. However, the cells pre-treated with acetone extracts of all the three Acacia species significantly (P > 0.05) up-regulated the expression of antioxidant enzymes in a concentration dependent manner (25, 50 and 75 μg/mL). In conclusion, the findings of our study demonstrated that the acetone extract of Acacia species effectively inhibited H2O2 mediated oxidative stress and may be useful as a therapeutic agent in preventing oxidative stress mediated diseases.
    Matched MeSH terms: Glutathione Peroxidase
  16. Lee CY, Hemingway J, Yap HH, Chong NL
    Med Vet Entomol, 2000 Mar;14(1):11-8.
    PMID: 10759307
    The possible insecticide resistance mechanisms of four Malaysian field-collected strains of the German cockroach, Blattella germanica (Linnaeus) (Dictyoptera: Blattellidae), were characterized with biochemical assays and native polyacrylamide gel electrophoresis (PAGE). Elevated esterase activity (at low to moderate frequency) and altered acetylcholinesterase (low frequency) were detected in all field strains, while elevated glutathione S-transferase levels were present in only two strains. Seven esterase bands were separated by native PAGE; a greater intensity occurred in three bands in the resistant strains compared to the susceptible strain. Inhibition studies using specific inhibitors on polyacrylamide gels suggested that the slowest of these three esterases is a cholinesterase, while the other two are carboxylesterases with a preference for beta- over alpha-naphthyl acetate.
    Matched MeSH terms: Glutathione Transferase/metabolism
  17. Lee HL, Chong WL
    PMID: 8525405
    Comparative DDT-susceptibility status and glutathion s-transferase (GST) activity of Malaysian Anopheles maculatus, Culex quinquefasciatus and Aedes aegypti was investigated to ascertain the role of this enzyme in DDT resistance. The standardised WHO dose-mortality bioassay tests were used to determine DDT susceptibility in these mosquitos, whilst GST microassay (Brogdon and Barber, 1990) was conducted to measure the activity of this enzyme in mosquito homogenate. It appeared that DDT susceptibility status of Malaysian mosquitos was not correlated with GST activity.
    Matched MeSH terms: Glutathione Transferase/metabolism*
  18. Rajah T, Chow SC
    Toxicol Appl Pharmacol, 2014 Jul 15;278(2):100-6.
    PMID: 24768707 DOI: 10.1016/j.taap.2014.04.014
    The caspase inhibitor benzyloxycarbony (Cbz)-l-Val-Ala-Asp (OMe)-fluoromethylketone (z-VAD-FMK) has recently been shown to inhibit T cell proliferation without blocking caspase-8 and caspase-3 activation in primary T cells. We showed in this study that z-VAD-FMK treatment leads to a decrease in intracellular glutathione (GSH) with a concomitant increase in reactive oxygen species (ROS) levels in activated T cells. The inhibition of anti-CD3-mediated T cell proliferation induced by z-VAD-FMK was abolished by the presence of low molecular weight thiols such as GSH, N-acetylcysteine (NAC) and l-cysteine, whereas d-cysteine which cannot be metabolised to GSH has no effect. These results suggest that the depletion of intracellular GSH is the underlying cause of z-VAD-FMK-mediated inhibition of T cell activation and proliferation. The presence of exogenous GSH also attenuated the inhibition of anti-CD3-induced CD25 and CD69 expression mediated by z-VAD-FMK. However, none of the low molecular weight thiols were able to restore the caspase-inhibitory properties of z-VAD-FMK in activated T cells where caspase-8 and caspase-3 remain activated and processed into their respective subunits in the presence of the caspase inhibitor. This suggests that the inhibition of T cell proliferation can be uncoupled from the caspase-inhibitory properties of z-VAD-FMK. Taken together, the immunosuppressive effects in primary T cells mediated by z-VAD-FMK are due to oxidative stress via the depletion of GSH.
    Matched MeSH terms: Glutathione/metabolism
  19. Yeo EH, Goh WL, Chow SC
    Toxicol. Mech. Methods, 2018 Mar;28(3):157-166.
    PMID: 28849708 DOI: 10.1080/15376516.2017.1373882
    The leucine aminopeptidase inhibitor, benzyloxycarbonyl-leucine-chloromethylketone (z-L-CMK), was found to be toxic and readily induce cell death in Jurkat T cells. Dose-response studies show that lower concentration of z-L-CMK induced apoptosis in Jurkat T cells whereas higher concentration causes necrosis. In z-L-CMK-induced apoptosis, both the initiator caspases (-8 and -9) and effector caspases (-3 and -6) were processed to their respective subunits. However, the caspases remained intact in z-L-CMK-induced necrosis. The caspase inhibitor, z-VAD-FMK inhibited z-L-CMK-mediated apoptosis and caspase processing but has no effect on z-L-CMK-induced necrosis in Jurkat T cells. The high mobility group protein B1 (HMGB1) protein was found to be released into the culture medium by the necrotic cells and not the apoptotic cells. These results indicate that the necrotic cell death mediated by z-L-CMK at high concentrations is via classical necrosis rather than secondary necrosis. We also demonstrated that cell death mediated by z-L-CMK was associated with oxidative stress via the depletion of intracellular glutathione (GSH) and increase in reactive oxygen species (ROS), which was blocked by N-acetyl cysteine. Taken together, the results demonstrated that z-L-CMK is toxic to Jurkat T cells and induces apoptosis at low concentrations, while at higher concentrations the cells die of necrosis. The toxic side effects in Jurkat T cells mediated by z-L-CMK are associated with oxidative stress via the depletion of GSH and accumulation of ROS.
    Matched MeSH terms: Glutathione/antagonists & inhibitors; Glutathione/metabolism
  20. 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
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