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  1. Nathan SA, Qvist R, Puthucheary SD
    FEMS Immunol. Med. Microbiol., 2005 Feb 1;43(2):177-83.
    PMID: 15681148
    The oxidative response of Burkholderia pseudomallei and Escherichia coli infected macrophages from normal and melioidosis subjects was determined by measuring the production of nitric oxide which is one of the reactive nitrogen intermediates, and the activation state of these macrophages was determined by measuring the generation of 8-iso-PGF(2alpha), a bioactive product of free radical induced lipid peroxidation. Macrophages obtained from the melioidosis patients generated significantly lower levels of nitric oxide and 8-iso-PGF(2alpha) compared to macrophages obtained from the normal subjects (P<0.001). The reduced efficiency of the oxygen dependent microbicidal mechanism in macrophages of melioidosis patients may be one of the survival strategies developed by B. pseudomallei to remain viable intracellularly.
  2. Muniandy S, Qvist R, Zaini A, Chinna K, Ismail IS
    PMID: 16295560
    The concentration of plasma sialic acid was estimated using the modified chemical method and the more sensitive enzymatic method in 20 subjects with impaired glucose tolerance and 20 control subjects. The mean sialic acid concentration values of the control subjects and subjects with impaired glucose tolerance using the enzymatic method were 1.747 +/- 0.047 and 2.583 +/- 0.070 mmole/l and 1.753 +/- 0.067 and 2.591 +/- 1.02 mmole/l for the chemical method. The intra-assay coefficient of variation for the control subjects and for the subjects with impaired glucose tolerance were 1.963% and 1.583%, respectively, for the enzymatic assay and 2.728% and 2.431%, respectively, for the chemical assay. The inter-assay coefficient of variation for the control subjects and for the subjects with impaired glucose tolerance were 2.686% and 2.723% for the enzymatic assay, and 3.819% and 3.95% for the chemical assay. Since the values do not differ significantly, the chemical assay is a cost effective method that can be used in large epidemiological studies.
  3. Safi SZ, Qvist R, Yan GO, Ismail IS
    BMC Med Genomics, 2014;7:29.
    PMID: 24885710 DOI: 10.1186/1755-8794-7-29
    Aberrant epigenetic profiles are concomitant with a spectrum of developmental defects and diseases. Role of methylation is an increasingly accepted factor in the pathophysiology of diabetes and its associated complications. This study aims to examine the correlation between oxidative stress and methylation of β1, β2 and β3-adrenergic receptors and to analyze the differential variability in the expression of these genes under hyperglycemic conditions.
  4. Yelumalai S, Muniandy S, Zawiah Omar S, Qvist R
    J Clin Biochem Nutr, 2010 Nov;47(3):191-7.
    PMID: 21103027 DOI: 10.3164/jcbn.10-27
    Preeclampsia (PE) is a major contributor to maternal and fetal mortality. The cause of preeclampsia remains unclear, but oxidative stress on the endothelium leading to endothelial dysfunction is said to be the root cause of the disease. The aim of this study was to measure and determine the plasma levels of key angiogenic factors in pregnancy as an indicator for the early onset of preeclampsia in pregnancy. Plasma levels of circulating a soluble fms like tyrosine kinase-1 (sFlt-1), an anti-angiogenic factor, vascular endothelial growth factor (VEGF) and placental growth factor (PIGF), both pro-angiogenic factors were analyzed in normal pregnant Malaysian women (control group, n = 34), women with pregnant induced hypertension (PIH, n = 34) and women with preeclampsia (PE, n = 34) all at three gestational ages, 24-28 weeks (early pregnancy: EP), 32-36 weeks (late pregnancy: LP) and 6 weeks after delivery (postpartum: PN). The plasma levels of angiogenic factors were determined by ELISA. sFlt-1 levels were elevated in PIH and PE patients as compared to controls. PIGF and VEGF were significantly decreased in PIH and PE as compared to the controls. These results suggest that elevated concentration of sFlt-1 and suppressed levels of PIGF and VEGF may contribute to the development of hypertension in pregnancy which precedes preeclampsia.
  5. Kaviarasan S, Muniandy S, Qvist R, Ismail IS
    J Clin Biochem Nutr, 2009 Jul;45(1):1-8.
    PMID: 19590700 DOI: 10.3164/jcbn.08-266
    Oxidative stress (OS) has been implicated as one of the major underlying mechanisms behind many acute and chronic diseases. However, the measurement of free radicals or their end products is complicated. Isoprostanes, derived from the non-enzymatic peroxidation of arachidonic acid are now considered to be reliable biomarkers of oxidant stress in the human body. Isoprostanes are involved in many of the human diseases such as type 2 diabetes. In type 2 diabetes elevated levels of F(2)-Isoprostanes (F(2)-IsoPs) have been observed. The measurement of bioactive F(2)-IsoPs levels offers a unique noninvasive analytical tool to study the role of free radicals in physiology, oxidative stress-related diseases, and acute or chronic inflammatory conditions. Measurement of oxidative stress by various other methods lacks specificity and sensitivity. This review aims to shed light on the implemention of F(2)-IsoPs measurement as a gold-standard biomarker of oxidative stress in type 2 diabetics.
  6. Qvist R, Ismail IS, Chinna K, Muniandy S
    Indian J Clin Biochem, 2008 Jul;23(3):246-9.
    PMID: 23105763 DOI: 10.1007/s12291-008-0055-x
    Although HbA(1C) is widely accepted as a useful index of mean blood glucose in type 2 diabetic patients its usefulness as screening test for diabetes has been controversial. The present study was undertaken to determine whether the level of HbA(1C) predicted diabetes in a prediabetic group of subjects. Plasma lipids, oral glucose tolerance, HbA(1C) was determined in 90 normal control subjects, 57 offspring of one type 2 diabetes mellitus parent and 11 diagnosed type 2 diabetes mellitus individuals. The mean age of participants was 44.5 yrs (not significantly different amongst the three groups) and the mean body mass index was 26.8 (not significantly different amongst the three groups). Two hours after a 75 g glucose challenge, the offspring had a significantly higher plasma glucose level (mean = 7.1 mmol/L, p value = 0.002) than the normals. Similarly the HbA(1C) values were higher in the offspring than in the normals (mean = 5.78%, p value = 0.016). Besides the significantly higher values for oral glucose tolerance test and HbA(1C), the diabetics also were significantly higher for triglycerides (mean = 2.25mmol/L), total cholesterol (mean = 6.24mmol/L) and systolic blood pressure (mean = 138.45mm Hg) than the offspring (P value = 0.031, 0.006, 0.010) and the normals (P value = 0.026, 0.018, 0.002) respectively. The mean values of diastolic blood pressure, LDL cholesterol and HDL cholesterol were not significantly different amongst the three groups.
    Study site: Diabetic clinic, University of Malaya Medical centre (UMMC), Kuala Lumpur, Malaysia
  7. Omar SZ, Qvist R, Khaing SL, Muniandy S, Bhalla S
    J Obstet Gynaecol Res, 2008 Apr;34(2):174-8.
    PMID: 18412778 DOI: 10.1111/j.1447-0756.2008.00755.x
    The aim of the present study was to determine the existence or prevalence of thrombophilic markers such as Factor V Leiden, prothrombin G20210A, protein S, protein C, activated protein C and anti-thrombin in pre-eclampsia and pregnancy-induced hypertensive patients.
  8. Safi SZ, Qvist R, Kumar S, Batumalaie K, Ismail IS
    Biomed Res Int, 2014;2014:801269.
    PMID: 25105142 DOI: 10.1155/2014/801269
    The growing number of people with diabetes worldwide suggests that diabetic retinopathy (DR) and diabetic macular edema (DME) will continue to be sight threatening factors. The pathogenesis of diabetic retinopathy is a widespread cause of visual impairment in the world and a range of hyperglycemia-linked pathways have been implicated in the initiation and progression of this condition. Despite understanding the polyol pathway flux, activation of protein kinase C (KPC) isoforms, increased hexosamine pathway flux, and increased advanced glycation end-product (AGE) formation, pathogenic mechanisms underlying diabetes induced vision loss are not fully understood. The purpose of this paper is to review molecular mechanisms that regulate cell survival and apoptosis of retinal cells and discuss new and exciting therapeutic targets with comparison to the old and inefficient preventive strategies. This review highlights the recent advancements in understanding hyperglycemia-induced biochemical and molecular alterations, systemic metabolic factors, and aberrant activation of signaling cascades that ultimately lead to activation of a number of transcription factors causing functional and structural damage to retinal cells. It also reviews the established interventions and emerging molecular targets to avert diabetic retinopathy and its associated risk factors.
  9. Muniandy S, Qvist R, Yan GO, Bee CJ, Chu YK, Rayappan AV
    J. Med. Invest., 2009 Feb;56(1-2):6-10.
    PMID: 19262007
    Hyperglycemia and insulin resistance are common in many critically ill patients. Hyperglycemia increases the production of reactive oxygen species in cells, stimulates the production of the potent proinflammatory cytokines IL-8 and TNF-alpha, and enhances the expression of haem oxygenase-1, an inducible stress protein. It has been shown that administration of insulin and the semi-essential amino acid glutamine have been beneficial to the septic patient. The aim of our study is to test whether these two molecules, glutamine and insulin used in combination attenuate the proinflammatory responses in endothelial cells which have been triggered by hyperglycaemia. Our results demonstrate that a combination of insulin and glutamine are significantly more effective in reducing the expression of IL-8, TNF-alpha and HO-1 than insulin or glutamine alone.
  10. Safi SZ, Shah H, Qvist R, Bindal P, Mansor M, Yan GOS, et al.
    Cell Physiol Biochem, 2018;51(3):1429-1436.
    PMID: 30485834 DOI: 10.1159/000495591
    BACKGROUND/AIMS: NF-κB induces transcription of a number of genes, associated with inflammation and apoptosis. In this study, we have investigated the effect of β-adrenergic receptor stimulation on NF-κB and IκBα in HUVECs.

    METHODS: Human umbilical vein endothelial cells (HUVECs) were cultured in high and low glucose concentrations. All HUVECs were treated with different concentrations of isoproterenol and propranolol for different time periods. The analytical procedures consisted of Western Blot, ELISA, DCFH-DA and TUNEL assays.

    RESULTS: Isoproterenol (agonist of a beta-adrenergic receptor) significantly reduced phosphorylation at Ser-536 of NF-κB; and Ser-32 and Ser-36 of IκBα in hyperglycemic HUVECs. Isoproterenol also significantly reduced apoptosis and ROS generation. No effect of IκBα was observed on Tyr-42 phosphorylation. The effect of isoproterenol was reversed by the antagonist propranolol. We also checked if NF-κB inhibitor MG132 causes any change at the level of apoptosis. However, we observed an almost similar effect.

    CONCLUSION: Given data demonstrates that beta-adrenergic receptors stimulation has a protective effect on HUVECs that might be occuring via NF-κβ and IκBα pathway.

  11. Batumalaie K, Qvist R, Yusof KM, Ismail IS, Sekaran SD
    Clin Exp Med, 2014 May;14(2):185-95.
    PMID: 23584372 DOI: 10.1007/s10238-013-0236-7
    Type 2 diabetes consists of progressive hyperglycemia, insulin resistance, and pancreatic β-cell failure which could result from glucose toxicity, inflammatory cytokines, and oxidative stress. In the present study, we investigate the effect of pretreatment with Gelam honey (Melaleuca spp.) and the individual flavonoid components chrysin, luteolin, and quercetin, on the production of reactive oxygen species (ROS), cell viability, lipid peroxidation, and insulin content in hamster pancreatic cells (HIT-T15 cells), cultured under normal and hyperglycemic conditions. Phenolic extracts from a local Malaysian species of Gelam honey (Melaleuca spp.) were prepared using the standard extraction methods. HIT-T15 cells were cultured in 5 % CO2 and then preincubated with Gelam honey extracts (20, 40, 60, and 80 μg/ml) as well as some of its flavonoid components chrysin, luteolin, and quercetin (20, 40, 60, and 80 μM), prior to stimulation by 20 and 50 mM of glucose. The antioxidative effects were measured in these cultured cells at different concentrations and time point by DCFH-DA assay. Pretreatment of cells with Gelam honey extract or the flavonoid components prior to culturing in 20 or 50 mM glucose showed a significant decrease in the production of ROS, glucose-induced lipid peroxidation, and a significant increase in insulin content and the viability of cells cultured under hyperglycemic condition. Our results show the in vitro antioxidative property of the Gelam honey and the flavonoids on the β-cells from hamsters and its cytoprotective effect against hyperglycemia.
  12. Batumalaie K, Zaman Safi S, Mohd Yusof K, Shah Ismail I, Devi Sekaran S, Qvist R
    Int J Endocrinol, 2013;2013:367312.
    PMID: 24324490 DOI: 10.1155/2013/367312
    Background. Oxidative stress induced by reactive oxygen and nitrogen species is critically involved in the impairment of β -cell function during the development of diabetes. Methods. HIT-T15 cells were cultured in 5% CO2 and then preincubated with Gelam honey extracts (20, 40, 60, and 80 µg/mL) as well as quercetin (20, 40, 60, and 80 µM), prior to stimulation by 20 and 50 mM of glucose. Cell lysate was collected to determine the effect of honey extracts and quercetin on the stress activated NF- κ B, MAPK pathways, and the Akt (ser473) activated insulin signaling pathway. Results. HIT-T15 cells cultured under hyperglycemic conditions demonstrated insulin resistance with a significant increase in the levels of MAPK, NF- κ B, and IRS-1 serine phosphorylation (ser307); however, Akt expression and insulin contents are significantly decreased. Pretreatment with quercetin and Gelam honey extract improved insulin resistance and insulin content by reducing the expression of MAPK, NF- κ B, and IRS-1 serine phosphorylation (ser307) and increasing the expression of Akt significantly. Conclusion. Gelam honey-induced differential expression of MAPK, NF- κ B, IRS-1 (ser307), and Akt in HIT-T15 cells shows that Gelam honey exerts protective effects against diabetes- and hyperglycemia-induced oxidative stress by improving insulin content and insulin resistance.
  13. Safi SZ, Batumalaie K, Qvist R, Mohd Yusof K, Ismail IS
    PMID: 27034691 DOI: 10.1155/2016/5843615
    Purpose. Type 2 diabetes consists of progressive hyperglycemia and insulin resistance, which could result from glucose toxicity, inflammatory cytokines, and oxidative stress. In the present study we investigated the effect of Gelam honey and quercetin on the oxidative stress-induced inflammatory pathways and the proinflammatory cytokines. Methods. HIT-T15 cells were cultured and preincubated with the extract of Gelam honey (20, 40, 60, and 80 μg/mL), as well as quercetin (20, 40, 60, and 80 μM), prior to stimulation by 20 and 50 mM glucose. Results. HIT-T15 cells cultured under hyperglycemic condition showed a significant increase in the inflammatory pathways by phosphorylating JNK, IKK-β, and IRS-1 at Ser307 (p < 0.05). There was a significant decrease in the phosphorylation of Akt at Ser473 (p < 0.05). Pretreatment with Gelam honey and quercetin reduced the expression of phosphorylated JNK, IKK-β, and IRS-1, thereby significantly reducing the expression of proinflammatory cytokines like TNF-α, IL-6, and IL-1β (p < 0.05). At the same time there was a significant increase in the phosphorylated Akt showing the protective effects against inflammation and insulin resistance (p < 0.05). In conclusion, our data suggest the potential use of the extract from Gelam honey and quercetin in modulating the inflammation induced insulin signaling pathways.
  14. Safi SZ, Qvist R, Ong G, Karimian H, Imran M, Shah I
    Arch Med Sci, 2017 Mar 01;13(2):470-480.
    PMID: 28261303 DOI: 10.5114/aoms.2016.64131
    INTRODUCTION: It is a widely held view that a progressive reduction of beta-cell mass occurs in the progression of diabetes. RAF-1 kinase and pancreas duodenal homeobox 1 (PDX-1) are major factors that promote survival of cells and maintain normal insulin functions. In this study we investigated the effect of a β-adrenergic receptor agonist and antagonist on RAF-1 and PDX-1, and their respective effects on apoptosis and insulin release in RIN-m5F cells.

    MATERIAL AND METHODS: RIN-m5F cells were cultured in normal (5 mM) and high (25 mM) glucose to mimic diabetic conditions, followed by treatment with 5 µM, 10 µM and 20 µM of isoproterenol and isoproterenol + propranolol for 6, 12 and 24 h. Western blotting and reverse transcription analysis were performed to examine the expression of RAF-1 and PDX-1. Annexin-V-FITC and terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) assays were used to investigate apoptosis. ELISA was used to measure insulin levels. Reverse transcription polymerase chain reaction was conducted to investigate the expression of genes.

    RESULTS: Stimulation of β-adrenergic receptors with isoproterenol significantly induced RAF-1 and PDX-1 genes in a concentration-dependent and time-independent manner. Changes were significant both at protein and mRNA levels. Up-regulation of RAF-1 and PDX-1 was accompanied by improved insulin levels and reduced apoptosis. Concentrations of 10 µM and 20 µM for 12 and 24 h were more effective in achieving significant differences in the experimental and control groups. Propranolol reversed the effect of isoproterenol mostly at maximum concentrations and time periods.

    CONCLUSIONS: A positive effect of a β-adrenergic agonist on RAF-1 and PDX-1, reduction in β-cell apoptosis and improved insulin contents can help to understand the pathogenesis of diabetes and to develop novel approaches for the β-cell dysfunction in diabetes.

  15. Akter R, Vythilingam I, Khaw LT, Qvist R, Lim YA, Sitam FT, et al.
    Malar J, 2015 Oct 05;14:386.
    PMID: 26437652 DOI: 10.1186/s12936-015-0856-3
    BACKGROUND: Malaria is a vector-borne parasitic disease which is prevalent in many developing countries. Recently, it has been found that Plasmodium knowlesi, a simian malaria parasite can be life-threatening to humans. Long-tailed macaques, which are widely distributed in Malaysia, are the natural hosts for simian malaria, including P. knowlesi. The aim of the present study was to determine the prevalence of simian malaria parasites in long-tailed macaques in the district of Hulu Selangor, Selangor, Malaysia.

    METHODS: A total of 70 blood samples were collected from Macaca fascicularis dwelling in the forest of Hulu Selangor by the Department of Wildlife and National Parks Peninsular Malaysia, Kuala Lumpur, Malaysia. DNA was extracted using PureLink™ Genomic DNA Kits. Conventional and nested PCR were used to detect the genus and species of Plasmodium parasites respectively. In addition, phylogenetic analysis was carried out to confirm the species of Plasmodium parasites.

    RESULTS: Thirty-five (50 %) of the 70 samples were positive for Plasmodium using genus-specific primers. These positive samples were then subjected to nested PCR targeting the 18S ribosomal RNA genes to detect all five simian malaria parasites: namely, P. knowlesi, Plasmodium inui, Plasmodium cynomolgi, Plasmodium fieldi, and Plasmodium coatneyi. All five species of simian malaria parasites were detected. Of these, P. inui was the predominant (65.7 %), followed by P. knowlesi (60 %), P. cynomolgi (51.4 %) P. coatneyi (45.7 %) and P. fieldi (2.9 %). A total of nine macaques had mono-infection with P. knowlesi (four), P. cynomolgi (two), P. coatneyi (two) and P. fieldi (one). Eleven of the macaques had dual infections while 12 had triple infections. Three macaques were infected with four species of Plasmodium. Molecular and phylogenetic analysis confirmed the five species of Plasmodium parasites.

    CONCLUSION: This study has provided evidence to elucidate the presence of transmission of malaria parasites among the local macaques in Hulu Selangor. Since malaria is a zoonosis, it is important to determine the new control strategies for the control of malaria.

  16. Safi SZ, Batumalaie K, Mansor M, Chinna K, Mohan S, Karimian H, et al.
    Clinics (Sao Paulo), 2015 Aug;70(8):569-76.
    PMID: 26247670 DOI: 10.6061/clinics/2015(08)07
    The aim of this study was to determine the in vitro effect of glutamine and insulin on apoptosis, mitochondrial membrane potential, cell permeability, and inflammatory cytokines in hyperglycemic umbilical vein endothelial cells.
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