Displaying publications 81 - 100 of 232 in total

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  1. Fulltext A reference genome and methylome for the Plasmodium knowlesi A1-H.1 line
    Benavente ED, de Sessions PF, Moon RW, Grainger M, Holder AA, Blackman MJ, et al.
    Int J Parasitol, 2018 03;48(3-4):191-196.
    PMID: 29258833 DOI: 10.1016/j.ijpara.2017.09.008
    Plasmodium knowlesi, a common parasite of macaques, is recognised as a significant cause of human malaria in Malaysia. The P. knowlesi A1H1 line has been adapted to continuous culture in human erythrocytes, successfully providing an in vitro model to study the parasite. We have assembled a reference genome for the PkA1-H.1 line using PacBio long read combined with Illumina short read sequence data. Compared with the H-strain reference, the new reference has improved genome coverage and a novel description of methylation sites. The PkA1-H.1 reference will enhance the capabilities of the in vitro model to improve the understanding of P. knowlesi infection in humans.
    Matched MeSH terms: Erythrocytes/parasitology
  2. Effect of Artocarpus integer lectin on functional activity of guinea-pig complement
    Hashim OH, Gendeh GS, Cheong CN, Jaafar MI
    Immunol Invest, 1994 Mar;23(2):153-60.
    PMID: 8194855
    The effect of Artocarpus integer lectin (lectin C) on the functional activity of guinea-pig complement was investigated. Purified and crude extract of lectin C from six cultivars of Artocarpus integer seeds were found to consume complement and thus decreased the complement-induced haemolytic activity of sensitized sheep erythrocytes. The change in the complement-mediated haemolytic activity was significantly decreased when incubation of the lectins was performed in the presence of melibiose. The reversal effect of the carbohydrate, which is a potent inhibitor of the lectin's binding to O-linked oligosaccharides of glycoprotein, demonstrate involvement of the lectins interaction with O-glycans of glycoproteins in the consumption of guinea-pig complement.
    Matched MeSH terms: Erythrocytes/drug effects
  3. In vivo anxiolytic and in vitro anti-inflammatory activities of water-soluble extract (WSE) of Nigella sativa (L.) seeds
    Babar ZM, Jaswir I, Tareq AM, Ali Reza ASM, Azizi WM, Hafidz M, et al.
    Nat Prod Res, 2021 Aug;35(16):2793-2798.
    PMID: 31578877 DOI: 10.1080/14786419.2019.1667348
    The WSE is a highly polar, gummy and mucilaginous bioactive content of the Nigella sativa (L.) seeds. This study reports the anxiolytic and anti-inflammatory effects of WSE investigated using Elevated Plus Maze (EPM) and Hole-Board Test (HBT) in adult mice and human RBCs haemolysis inhibition and protein denaturation respectively. The oral WSE treatment (100 & 200 mg/kg b.w/day) for 72 hours has exhibited slightly better anxiolytic effect (p 
    Matched MeSH terms: Erythrocytes/drug effects
  4. Red cell glyoxalase I and placental soluble aconitase polymorphisms in the three major ethnic groups of Malaysia
    Teng YS, Tan SG, Ng T, Lopez CG
    Jinrui Idengaku Zasshi, 1978 Sep;23(3):211-5.
    PMID: 732016
    Matched MeSH terms: Erythrocytes/enzymology*
  5. Human red cell adenylate kinase polymorphism in West Malaysian populations
    Chan KL
    Hum. Hered., 1971;21(2):173-9.
    PMID: 5127408
    Matched MeSH terms: Erythrocytes/enzymology*
  6. Adenylate kinase and malate dehydrogenase in four Malaysian racial groups
    Welch QB, Luan Eng LI, Bolton JM
    Humangenetik, 1971;14(1):61-3.
    PMID: 5144903
    Matched MeSH terms: Erythrocytes/enzymology
  7. Erythrocyte G-6-PD deficiency among Chinese and Malays of Singapore
    Saha N, Banerjee B
    Trop Geogr Med, 1971 Jun;23(2):141-4.
    PMID: 5568538
    Matched MeSH terms: Erythrocytes/enzymology*
  8. Fulltext In vitro invasion inhibition assay using antibodies against Plasmodium knowlesi Duffy binding protein alpha and apical membrane antigen protein 1 in human erythrocyte-adapted P. knowlesi A1-H.1 strain
    Muh F, Lee SK, Hoque MR, Han JH, Park JH, Firdaus ER, et al.
    Malar J, 2018 Jul 27;17(1):272.
    PMID: 30049277 DOI: 10.1186/s12936-018-2420-4
    BACKGROUND: The rapid process of malaria erythrocyte invasion involves ligand-receptor interactions. Inducing antibodies against specific ligands or receptors that abrogate the invasion process is a key challenge for blood stage vaccine development. However, few candidates were reported and remain to be validated for the discovery of new vaccine candidates in Plasmodium knowlesi.

    METHODS: In order to investigate the efficacy of pre-clinical vaccine candidates in P. knowlesi-infected human cases, this study describes an in vitro invasion inhibition assay, using a P. knowlesi strain adapted to in vitro growth in human erythrocytes, PkA1-H.1. Recombinant proteins of P. knowlesi Duffy binding protein alpha (PkDBPα) and apical membrane antigen 1 (PkAMA1) were produced in Escherichia coli system and rabbit antibodies were generated from immune animals.

    RESULTS: PkDBPα and PkAMA1 recombinant proteins were expressed as insoluble and produced as a functional refolded form for this study. Antibodies against PkDBPα and PkAMA1 specifically recognized recombinant proteins and native parasite proteins in schizont-stage parasites on the merozoite organelles. Single and combination of anti-PkDBPα and anti-PkAMA1 antibodies elicited strong growth inhibitory effects on the parasite in concentration-dependent manner. Meanwhile, IgG prevalence of PkDBPα and PkAMA1 were observed in 13.0 and 46.7% in human clinical patients, respectively.

    CONCLUSION: These data provide support for the validation of in vitro growth inhibition assay using antibodies of DBPα and AMA1 in human-adapted P. knowlesi parasite PkA1-H.1 strain.

    Matched MeSH terms: Erythrocytes/parasitology*
  9. In vitro evaluation of Cuscuta reflexa Roxb. for thrombolytic, antioxidant, membrane stabilizing and antimicrobial activities
    Azad AK, Laboni FR, Rashid H, Ferdous S, Rashid SS, Kamal N, et al.
    Nat Prod Res, 2020 Aug;34(16):2394-2397.
    PMID: 30475649 DOI: 10.1080/14786419.2018.1538216
    The key purpose of this experiment was to evaluate the thrombolytic, antioxidant, membrane stabilizing and antimicrobial potentials of crude ethanol extracts (CEE) of whole plant, organic and aqueous soluble fractions (OF & AQSF). CEE showed the highest (44.63%) clot lysis activity compared to streptokinase (64.35%). In DPPH study, petroleum ether soluble fraction (PSF) has exhibited IC50 of 18.83 μg/mL while the standard ascorbic acid was 2.48 µg/mL. AQSF profoundly inhibited the lysis of erythrocytes (66.20%) which was insignificantly different (p > 0.05) to acetylsalicylic acid (71.98%), the reference. However, AQSF showed a significantly stronger level of protection against heat-induced hemolysis (64.80%) as compared with the acetylsalicylic acid (78.90%). CEE, OF and AQSF have displayed reasonable growth of inhibition of tested bacteria compared to negative control and standard drug (77.50 mg of GAE/g).
    Matched MeSH terms: Erythrocytes/drug effects
  10. Molecular Detection of Glycophorins A and B Variant Phenotypes and their Clinical Relevance
    Hassan SN, Thirumulu Ponnuraj K, Mohamad S, Hassan R, Wan Ab Rahman WS
    Transfus Med Rev, 2019 04;33(2):118-124.
    PMID: 30910255 DOI: 10.1016/j.tmrv.2019.02.003
    Crossover or conversion between the homologous regions of glycophorin A (GYPA) and glycophorin B (GYPB) gives rise to several different hybrid glycophorin genes encoding a number of different glycophorin variant phenotypes which bear low prevalence antigens in the MNS blood group system. GP.Mur is the main glycophorin variant phenotype which causes hemolytic transfusion reaction (HTR) and hemolytic disease of the fetus and newborn (HDFN) in East and Southeast Asians. The detection of glycophorin variant phenotypes using serological methods is limited to phenotyping reagents that are not commercially available. Moreover, the red blood cells used for antibody identification are usually of the GP.Mur phenotype. The current Polymerase Chain Reaction (PCR)-based methods and loop-mediated isothermal amplification (LAMP) are available alternatives to phenotyping that allow for the specific detection of glycophorin variant phenotypes. This review highlights the molecular detection method for glycophorins A and B variant phenotypes and their clinical relevance.
    Matched MeSH terms: Erythrocytes/immunology
  11. Sub-lethal concentrations of artemisinin alter pH of the digestive vacuole of the malaria parasite, Plasmodium falciparum
    Ibrahim N, Roslee A, Azlan M, Abu-Bakar N
    Trop Biomed, 2020 Mar 01;37(1):1-14.
    PMID: 33612713
    An appropriate pH maintenance within a membrane-enclosed organelle is vital for the occurrence of biological processes. Artemisinin (ART), a potent antimalarial drug has been reported to target the digestive vacuole (DV) of Plasmodium falciparum, which might alter the pH of the organelle, thereby impairing the hemoglobin degradation and subsequent heme detoxification. Hence, a flow cytometry-based technique using fluorescein isothiocyanate-dextran (FITC-dextran) as a ratiometric pH probe was employed to measure the pH of the DV of the malaria parasite treated with ART. Based on the pH calibration curve generated, the steady-state pH of the acidic DV of the non-treated parasites was 5.42 ± 0.11, indicating that FITC-dextran is suitable for detection of physiological pH of the organelle. The alteration of the DV pH occurred when the parasites were treated with ART even at the sub-lethal concentrations (15 and 30 nM) used. The similar effect was shown by the parasites treated with a standard proton pump inhibitor, concanamycin A. This suggests that ART might have altered the DV pH at lower levels than the level needed to kill the parasite. This study has important implications in designing new ART treatment strategies and in generating new endoperoxide-based antimalarial drugs pertaining to the interruption of the pH regulation of the malaria parasite's DV.
    Matched MeSH terms: Erythrocytes/parasitology
  12. Purification of Plasmodium and Babesia- infected erythrocytes using a non-woven fabric filter
    Tao ZY, Liu WP, Dong J, Feng XX, Yao DW, Lv QL, et al.
    Trop Biomed, 2020 Dec 01;37(4):911-918.
    PMID: 33612745 DOI: 10.47665/tb.37.4.911
    The purification of parasite-infected erythrocytes from whole blood containing leucocytes is crucial for many downstream genetic and molecular assays in parasitology. Current methodologies to achieve this are often costly and time consuming. Here, we demonstrate the successful application of a cheap and simple Non-Woven Fabric (NWF) filter for the purification of parasitized red blood cells from whole blood. NWF filtration was applied to the malaria-parasitized blood of three strains of mice, and one strain of rat, and to Babesia gibsoni parasitized dog blood. Before and after filtration, the white blood cell (WBC) removal rates and red blood cell (RBC) recovery rates were measured. After NWF filter treatment of rodent malaria-infected blood, the WBC removal rates and RBC recovery rates were, for Kunming mice: 99.51%±0.30% and 86.12%±8.37%; for BALB/C mice: 99.61%±0.15% and 80.74%±7.11%; for C57 mice: 99.71%±0.12% and 84.87%±3.83%; for Sprague-Dawley rats: 99.93%±0.03% and 83.30%±2.96%. Microscopy showed WBCs were efficiently removed from infected dog blood samples, and there was no obvious morphological change of B. gibsoni parasites. NWF filters efficiently remove leukocytes from malaria parasite-infected mouse and rat blood, and are also suitable for filtration of B. gibsoni-infected dog blood.
    Matched MeSH terms: Erythrocytes/parasitology*
  13. Fulltext A Basis for Rapid Clearance of Circulating Ring-Stage Malaria Parasites by the Spiroindolone KAE609
    Zhang R, Suwanarusk R, Malleret B, Cooke BM, Nosten F, Lau YL, et al.
    J Infect Dis, 2016 Jan 1;213(1):100-4.
    PMID: 26136472 DOI: 10.1093/infdis/jiv358
    Recent clinical trials revealed a surprisingly rapid clearance of red blood cells (RBCs) infected with malaria parasites by the spiroindolone KAE609. Here, we show that ring-stage parasite-infected RBCs exposed to KAE609 become spherical and rigid, probably through osmotic dysregulation consequent to the disruption of the parasite's sodium efflux pump (adenosine triphosphate 4). We also show that this peculiar drug effect is likely to cause accelerated splenic clearance of the rheologically impaired Plasmodium vivax- and Plasmodium falciparum-infected RBCs.
    Matched MeSH terms: Erythrocytes/parasitology
  14. Fulltext The Duffy binding protein (PkDBPαII) of Plasmodium knowlesi from Peninsular Malaysia and Malaysian Borneo show different binding activity level to human erythrocytes
    Lim KL, Amir A, Lau YL, Fong MY
    Malar J, 2017 08 11;16(1):331.
    PMID: 28800732 DOI: 10.1186/s12936-017-1984-8
    BACKGROUND: The zoonotic Plasmodium knowlesi is a major cause of human malaria in Malaysia. This parasite uses the Duffy binding protein (PkDBPαII) to interact with the Duffy antigen receptor for chemokines (DARC) receptor on human and macaque erythrocytes to initiate invasion. Previous studies on P. knowlesi have reported distinct Peninsular Malaysia and Malaysian Borneo PkDBPαII haplotypes. In the present study, the differential binding activity of these haplotypes with human and macaque (Macaca fascicularis) erythrocytes was investigated.

    METHODS: The PkDBPαII of Peninsular Malaysia and Malaysian Borneo were expressed on the surface of COS-7 cells and tested with human and monkey erythrocytes, with and without anti-Fy6 (anti-Duffy) monoclonal antibody treatment. Binding activity level was determined by counting the number of rosettes formed between the transfected COS-7 cells and the erythrocytes.

    RESULTS: Anti-Fy6 treatment was shown to completely block the binding of human erythrocytes with the transfected COS-7 cells, thus verifying the specific binding of human DARC with PkDBPαII. Interestingly, the PkDBPαII of Peninsular Malaysia displayed a higher binding activity with human erythrocytes when compared with the Malaysian Borneo PkDBPαII haplotype (mean number of rosettes formed = 156.89 ± 6.62 and 46.00 ± 3.57, respectively; P 

    Matched MeSH terms: Erythrocytes/parasitology*
  15. Laser-induced changes of in vitro erythrocyte sedimentation rate
    Al Musawi MS, Jaafar MS, Al-Gailani B, Ahmed NM, Suhaimi FM
    Lasers Med Sci, 2017 Dec;32(9):2089-2095.
    PMID: 28967036 DOI: 10.1007/s10103-017-2340-5
    The study of the effects of low-level laser (LLL) radiation on blood is important for elucidating the mechanisms behind the interaction of LLL radiation and biologic tissues. Different therapy methods that involve blood irradiation have been developed and used for clinical purposes with beneficial effects. The aim of this study was to compare the effects of different irradiation protocols using a diode-pumped solid-state LLL (λ = 405 nm) on samples of human blood by measuring the erythrocyte sedimentation rate (ESR). Human blood samples were obtained through venipuncture into tubes containing EDTA as an anticoagulant. Every sample was divided into two equal aliquots to be used as an irradiated sample and a non-irradiated control sample. The irradiated aliquot was subjected to a laser beam with a wavelength of 405 nm and an energy density of 72 J/cm2. The radiation source had a fixed irradiance of 30 mW/cm2. The ESR change was observed for three different experimental protocols: irradiated whole blood, irradiated red blood cells (RBCs) samples re-suspended in non-irradiated blood plasma, and non-irradiated RBCs re-suspended in irradiated blood plasma. The ESR values were measured after laser irradiation and compared with the non-irradiated control samples. Irradiated blood plasma in which non-radiated RBCs were re-suspended was found to result in the largest ESR decrease for healthy human RBCs, 51%, when compared with RBCs re-suspended in non-irradiated blood plasma. The decrease in ESR induced by LLL irradiation of the plasma alone was likely related to changes in the plasma composition and an increase in the erythrocyte zeta potential upon re-suspension of the RBCs in the irradiated blood plasma.
    Matched MeSH terms: Erythrocytes/radiation effects*
  16. Altered antibacterial activity of Curcumin in the presence of serum albumin, plasma and whole blood
    Teow SY, Ali SA
    Pak J Pharm Sci, 2017 Mar;30(2):449-457.
    PMID: 28649069
    Antibacterial effect is one of the major therapeutic activities of plant-derived Curcumin. This work evaluated the effect of serum albumin, human plasma, and whole blood on the in vitro activity of Curcumin against eight clinical bacterial isolates by standard broth microdilution and plate-counting methods. Toxicological effects of Curcumin towards human red blood cells (RBCs) and peripheral blood mononuclear cells (PBMCs) were also investigated. Curcumin exhibited weak activity against gram-negative bacteria, except Escherichia coli and Shigella flexneri were susceptible and was most active against gram-positive bacteria: Staphylococcus aureus, Streptococcus pyogenes and Enterococcus faecalis. The antibacterial activity was impaired in the presence of bovine serum albumin (BSA), human plasma and whole blood. Curcumin was not toxic to PBMCs and RBCs at 200μg/mL. Furthermore, Curcumin showed synergistic activity in combination with antibiotics: Ciprofloxacin, Gentamicin, Vancomycin and Amikacin against Staphylococcus aureus. This study demonstrated that the interaction of Curcumin with plasma proteins diminishes its in vitro antibacterial activity. Curcumin derivatives with reduced affinity for plasma protein may improve the bioavailability and antibacterial activities.
    Matched MeSH terms: Erythrocytes/drug effects
  17. Fulltext Red cell autoantibodies among thalassaemia patients in Hospital Universiti Sains Malaysia
    Noor Haslina MN, Ariffin N, Illuni Hayati I, Rosline H
    Singapore Med J, 2007 Oct;48(10):922-5.
    PMID: 17909677
    Thalassaemia is one of the major public health problems in Malaysia. Regular monthly blood transfusion remains the main treatment for severe thalassaemia patients. One of the complications of blood transfusion is the formation by the recipients of alloantibodies and autoantibodies against red blood cell (RBC) antigen. The purpose of this study was to determine the prevalence of RBC autoantibodies among multiple-transfused thalassaemic patients in our institution and factors that contribute to its development.
    Matched MeSH terms: Erythrocytes/immunology*
  18. Fulltext The distribution of blood genetic markers in the Malay populations of the Malay Peninsula
    Hawkins BR
    Singapore Med J, 1974 Jun;15(2):118-27.
    PMID: 4416165
    Matched MeSH terms: Erythrocytes/enzymology
  19. Influence of alignment of the pyramid on its beneficial effects
    Bhat S, Rao G, Murthy KD, Bhat PG
    Indian J Exp Biol, 2007 May;45(5):455-8.
    PMID: 17569288
    The present study was aimed to find out whether a change in the alignment of the pyramid from the north-south axis causes any variation in the effects produced by it on plasma cortisol levels and markers of oxidative stress in erythrocytes of adult-female Wistar rats. Plasma cortisol and erythrocyte TBARS levels were significantly lower whereas erythrocyte GSH was significantly higher in rats kept in pyramid that was aligned on the four cardinal points--north, east, south and west, as compared to normal control rats. Although there was a significant difference in the plasma cortisol level between normal control group and the group of rats kept in randomly aligned pyramid, there was no significant difference between these two groups for the other parameters. Erythrocyte TBARS levels in the group of rats kept in the randomly aligned pyramid was significantly higher than that in the group kept in the magnetically aligned pyramid. The results suggest that the north-south alignment of the pyramid is crucial for its expected effects.
    Matched MeSH terms: Erythrocytes/chemistry
  20. Fulltext Normocyte-binding protein required for human erythrocyte invasion by the zoonotic malaria parasite Plasmodium knowlesi
    Moon RW, Sharaf H, Hastings CH, Ho YS, Nair MB, Rchiad Z, et al.
    Proc Natl Acad Sci U S A, 2016 Jun 28;113(26):7231-6.
    PMID: 27303038 DOI: 10.1073/pnas.1522469113
    The dominant cause of malaria in Malaysia is now Plasmodium knowlesi, a zoonotic parasite of cynomolgus macaque monkeys found throughout South East Asia. Comparative genomic analysis of parasites adapted to in vitro growth in either cynomolgus or human RBCs identified a genomic deletion that includes the gene encoding normocyte-binding protein Xa (NBPXa) in parasites growing in cynomolgus RBCs but not in human RBCs. Experimental deletion of the NBPXa gene in parasites adapted to growth in human RBCs (which retain the ability to grow in cynomolgus RBCs) restricted them to cynomolgus RBCs, demonstrating that this gene is selectively required for parasite multiplication and growth in human RBCs. NBPXa-null parasites could bind to human RBCs, but invasion of these cells was severely impaired. Therefore, NBPXa is identified as a key mediator of P. knowlesi human infection and may be a target for vaccine development against this emerging pathogen.
    Matched MeSH terms: Erythrocytes/parasitology*
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