Displaying publications 1 - 20 of 116 in total

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  1. van de Merwe JP, Hodge M, Olszowy HA, Whittier JM, Ibrahim K, Lee SY
    Environ Health Perspect, 2009 Sep;117(9):1397-401.
    PMID: 19750104 DOI: 10.1289/ehp.0900813
    Persistent organic pollutants (POPs)-such as organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), and polybrominated diphenyl ethers (PBDEs)-and heavy metals have been reported in sea turtles at various stages of their life cycle. These chemicals can disrupt development and function of wildlife. Furthermore, in areas such as Peninsular Malaysia, where the human consumption of sea turtle eggs is prevalent, egg contamination may also have public health implications.
  2. Yu CY, Ang GY, Chua AL, Tan EH, Lee SY, Falero-Diaz G, et al.
    J Microbiol Methods, 2011 Sep;86(3):277-82.
    PMID: 21571011 DOI: 10.1016/j.mimet.2011.04.020
    Cholera is a communicable disease caused by consumption of contaminated food and water. This potentially fatal intestinal infection is characterised by profuse secretion of rice watery stool that can rapidly lead to severe dehydration and shock, thus requiring treatment to be given immediately. Epidemic and pandemic cholera are exclusively associated with Vibrio cholerae serogroups O1 and O139. In light of the need for rapid diagnosis of cholera and to prevent spread of outbreaks, we have developed and evaluated a direct one-step lateral flow biosensor for the simultaneous detection of both V. cholerae O1 and O139 serogroups using alkaline peptone water culture. Serogroup specific monoclonal antibodies raised against lipopolysaccharides (LPS) were used to functionalize the colloidal gold nanoparticles for dual detection in the biosensor. The assay is based on immunochromatographic principle where antigen-antibody reaction would result in the accumulation of gold nanoparticles and thus, the appearance of a red line on the strip. The dry-reagent dipstick format of the biosensor ensure user-friendly application, rapid result that can be read with the naked eyes and cold-chain free storage that is well-suited to be performed at resource-limited settings.
  3. Yeo JG, Wasser M, Kumar P, Pan L, Poh SL, Ally F, et al.
    Nat Biotechnol, 2020 06;38(6):757.
    PMID: 32467644 DOI: 10.1038/s41587-020-0574-4
    An amendment to this paper has been published and can be accessed via a link at the top of the paper.
  4. Yeap CSY, Chaibun T, Lee SY, Zhao B, Jan Y, La-O-Vorakiat C, et al.
    Chem Commun (Camb), 2021 Nov 16;57(91):12155-12158.
    PMID: 34726213 DOI: 10.1039/d1cc05181d
    We report a highly sensitive and selective multiplex assay by empowering an electrochemical DNA sensor with isothermal rolling circle amplification. The assay could simultaneously detect and discriminate three common entero-pathogens in a single reaction, with femtomolar sensitivity. It is useful for field- or resource-limited settings.
  5. Xu G, Zhang C, Lee SY, Chen Z, Zeng X
    Mitochondrial DNA B Resour, 2023;8(1):181-185.
    PMID: 36713297 DOI: 10.1080/23802359.2023.2168114
    Christella dentata (Forssk.) Brownsey & Jermy (Thelypteridaceae) is endemic to the tropical and subtropical regions of Africa, Asia, and Asia Pacific. In this study, the complete chloroplast genome sequence of C. dentata was assembled using next-generation sequencing data. The complete chloroplast genome was 151,662 bp in length and had a typical quadripartite structure, which consisted of a small single-copy region (21,776 bp) and a large single-copy region (82,624 bp) that were separated by a pair of inverted repeats (23,631 bp each). A total of 131 genes were predicted, including 89 protein coding (CDS), 34 tRNA, and eight rRNA genes. The overall GC content of the chloroplast genome was 42.48%. Based on the concatenated shared unique CDS sequence dataset, phylogenetic analysis using both the maximum-likelihood and the Bayesian inference methods revealed that C. dentata is placed within Thelypteridaceae and is closely related to Christella appendiculata. Such genetic information would be useful for studies on the evolution pattern in ferns. The availability of chloroplast genome sequence for the species also paves the way to resolving the complicated relationship among members of Christella.
  6. Xu G, Li Z, Chen Z, Lee SY, Kong X
    Mitochondrial DNA B Resour, 2023;8(10):1137-1140.
    PMID: 37928400 DOI: 10.1080/23802359.2023.2270207
    Oreocharis argyreia var. angustifolia of Gesneriaceae is widely distributed in South China, including Guangdong, Guangxi, Hunan, and Jiangxi provinces. However, genetic information of this species is limited, further contributing to the taxonomic complications surrounding this species. Thus, in this study, we assembled and characterized the complete chloroplast genome of O. argyreia var. angustifolia as a genomic resource for future studies. The complete plastid genome was 154,675 bp in size, with a pair of inverted repeat regions of 25,329 bp each, separating the 85,977-bp large and 18,040-bp small single copy regions. A total of 131 genes were predicted, consisting of 86 protein-coding, 37 tRNA, and eight rRNA genes. The overall GC content was 37.6%. Phylogenetic analysis based on 79 shared unique CDS resulted in a fully resolved phylogenetic tree using both the maximum likelihood and Bayesian inference methods. Based on current circumscription, both methods indicated that Oreocharis is monophyletic; O. argyreia var. angustifolia diverged after O. chienii, which then followed by the divergence of the other three species included namely, O. continifolia, O. esquirolii, and O. mileensis. The genomic data obtained will be useful for future studies on the phylogenetics and evolution of Gesneriaceae.
  7. Wu Y, Han Y, Tao Y, Li D, Xie G, Show PL, et al.
    Food Res Int, 2020 06;132:109098.
    PMID: 32331662 DOI: 10.1016/j.foodres.2020.109098
    In this study, four different selected wall materials (namely gelatin, soy protein isolate, maltodextrin and Arabic gum) were applied for blueberry anthocyanin extract encapsulation. The effect of these wall material types on the release and degradation of anthocyanin and the modulation of gut microbiota during in vitro simulated gastrointestinal digestion and colonic fermentation were investigated. It was found that the encapsulation of anthocyanin extract using appropriate wall material could significantly enhance the colonic accessibility of anthocyanins. Soy protein isolate and gelatin delayed the release of anthocyanins, whereas the other two wall materials displayed no significant effect on the release time of anthocyanins. Gut microbiota mainly metabolized some phenolic compounds such as 4-hydroxycinnamic acid and chlorogenic acid. Meanwhile, different fermented anthocyanin extract microcapsule broth could significantly decrease the composition and abundance of Firmicutes and increase that of Bacteroidetes. Furthermore, the presence of anthocyanin extract microcapsules, especially those encapsulated with soy protein isolate, promoted the biosynthesis of short-chain fatty acids by gut microbiota. It is concluded that, amongst the wall materials studied, soy protein isolate appeared to be a functional and suitable candidate to delay anthocyanin release and prevent disease through the promotion of gut health.
  8. Wong YM, Wu TY, Ling TC, Show PL, Lee SY, Chang JS, et al.
    J Biosci Bioeng, 2018 May;125(5):590-598.
    PMID: 29352712 DOI: 10.1016/j.jbiosc.2017.12.012
    Three newly discovered H2 producing bacteria namely Clostridium perfringens strain JJC, Clostridium bifermentans strain WYM and Clostridium sp. strain Ade.TY originated from landfill leachate sludge have demonstrated highly efficient H2 production. The maximum H2 production attained from these isolates are in the descending order of strain C. perfringens strain JJC > C. bifermentans strain WYM > Clostridium sp. strain Ade.TY with yield of 4.68 ± 0.12, 3.29 ± 0.11, and 2.87 ± 0.10 mol H2/mol glucose, respectively. The result has broken the conventional theoretical yield of 4 mol H2/mol glucose. These isolates were thermodynamically favourable with Gibbs free energy between -33 and -35 kJ/mol (under process conditions: pH 6, 37 °C and 5 g/L glucose). All three isolates favour butyrate pathway for H2 production with the ratio of acetate and butyrate of 0.77, 0.65 and 0.80 for strain JJC, WYM and Ade.TY, respectively. This study reported provides a new insight on the potential of unique bacteria in H2 production.
  9. Wen WX, Allen J, Lai KN, Mariapun S, Hasan SN, Ng PS, et al.
    J Med Genet, 2018 02;55(2):97-103.
    PMID: 28993434 DOI: 10.1136/jmedgenet-2017-104947
    BACKGROUND: Genetic testing for BRCA1 and BRCA2 is offered typically to selected women based on age of onset and family history of cancer. However, current internationally accepted genetic testing referral guidelines are built mostly on data from cancer genetics clinics in women of European descent. To evaluate the appropriateness of such guidelines in Asians, we have determined the prevalence of germ line variants in an unselected cohort of Asian patients with breast cancer and healthy controls.

    METHODS: Germ line DNA from a hospital-based study of 2575 unselected patients with breast cancer and 2809 healthy controls were subjected to amplicon-based targeted sequencing of exonic and proximal splice site junction regions of BRCA1 and BRCA2 using the Fluidigm Access Array system, with sequencing conducted on a Illumina HiSeq2500 platform. Variant calling was performed with GATK UnifiedGenotyper and were validated by Sanger sequencing.

    RESULTS: Fifty-five (2.1%) BRCA1 and 66 (2.6%) BRCA2 deleterious mutations were identified among patients with breast cancer and five (0.18%) BRCA1 and six (0.21%) BRCA2 mutations among controls. One thousand one hundred and eighty-six (46%) patients and 97 (80%) carriers fulfilled the National Comprehensive Cancer Network guidelines for genetic testing.

    CONCLUSION: Five per cent of unselected Asian patients with breast cancer carry deleterious variants in BRCA1 or BRCA2. While current referral guidelines identified the majority of carriers, one in two patients would be referred for genetic services. Given that such services are largely unavailable in majority of low-resource settings in Asia, our study highlights the need for more efficient guidelines to identify at-risk individuals in Asia.

  10. Wen WX, Lee SY, Siang R, Koh RY
    Adv Ther, 2017 06;34(6):1245-1269.
    PMID: 28484954 DOI: 10.1007/s12325-017-0547-2
    Fibrosis is a potentially debilitating disease with high morbidity rates. It is estimated that half of all deaths that occur in the USA are attributed to fibrotic disorders. Fibrotic disorders are characterized primarily by disruption in the extracellular matrix deposition and breakdown equilibrium, leading to the accumulation of excessive amounts of extracellular matrix. Given the potentially high prevalence of fibrosis and the paucity of agents currently available for the treatment of this disease, there is an urgent need for the identification of drugs that can be utilized to treat the disease. Pentoxifylline is a methylxanthine derivative that is currently approved for the treatment of vascular diseases, in particular, claudication. Pentoxifylline has three main properties: improving the rheological properties of blood, anti-inflammatory, and antioxidative. Recently, the effectiveness of pentoxifylline in the treatment of fibrosis via attenuating and reversing fibrotic lesions has been demonstrated in several clinical trials and animal studies. As a result of the limited availability of antifibrotic agents in the long-term treatment of fibrosis that can attenuate and even reverse fibrotic lesions effectively, it would be of particular importance to consider the potential clinical utility of pentoxifylline in the treatment of fibrosis. Thus, this paper discusses the evolving roles of pentoxifylline in the treatment of different types of fibrosis.
  11. Wang ZF, Yu EP, Zeng QS, Deng HG, Cao HL, Li ZA, et al.
    Mitochondrial DNA B Resour, 2021;6(12):3327-3328.
    PMID: 34746403 DOI: 10.1080/23802359.2021.1994901
    Ormosia purpureiflora is endemic to China. It is named after its purple flowers. It is a small tree only up to 3 m. It has leathery leaves, racemose inflorescences. The seeds are elliptic and red in coat. It is only confined to Luofushan Provincial Nature Reserve in Huizhou of Guangdong Province. Herein, we first reported on its complete chloroplast genome sequence as genomic resource for conservation purposes. The chloroplast genome of O. purpureiflora was 173,364 bp in length, with a large single-copy region of 73,465 bp, a small single-copy region of 18,751 bp, and a pair of inverted repeat regions that were 40,574 bp each. A total of 90 protein-coding genes, 38 transfer RNA genes, and eight ribosomal RNA genes were predicted, while 106 simple sequence repeats were recorded throughout the genome. Phylogenetic analysis revealed that O. purpureiflora was sister to O. emarginata.
  12. Toh GT, Kang P, Lee SS, Lee DS, Lee SY, Selamat S, et al.
    PLoS One, 2008;3(4):e2024.
    PMID: 18431501 DOI: 10.1371/journal.pone.0002024
    BACKGROUND: In Asia, breast cancer is characterised by an early age of onset: In Malaysia, approximately 50% of cases occur in women under the age of 50 years. A proportion of these cases may be attributable, at least in part, to genetic components, but to date, the contribution of genetic components to breast cancer in many of Malaysia's ethnic groups has not been well-characterised.
    METHODOLOGY: Given that hereditary breast carcinoma is primarily due to germline mutations in one of two breast cancer susceptibility genes, BRCA1 and BRCA2, we have characterised the spectrum of BRCA mutations in a cohort of 37 individuals with early-onset disease (
  13. Thirthagiri E, Lee SY, Kang P, Lee DS, Toh GT, Selamat S, et al.
    Breast Cancer Res, 2008;10(4):R59.
    PMID: 18627636 DOI: 10.1186/bcr2118
    The cost of genetic testing and the limited knowledge about the BRCA1 and BRCA2 genes in different ethnic groups has limited its availability in medium- and low-resource countries, including Malaysia. In addition, the applicability of many risk-assessment tools, such as the Manchester Scoring System and BOADICEA (Breast and Ovarian Analysis of Disease Incidence and Carrier Estimation Algorithm) which were developed based on mutation rates observed primarily in Caucasian populations using data from multiplex families, and in populations where the rate of breast cancer is higher, has not been widely tested in Asia or in Asians living elsewhere. Here, we report the results of genetic testing for mutations in the BRCA1 or BRCA2 genes in a series of families with breast cancer in the multi-ethnic population (Malay, Chinese and Indian) of Malaysia.
  14. Teoh CS, Lee SY, Chiang SK, Chew TK, Goh AS
    Asian Pac J Cancer Prev, 2018 May 26;19(5):1229-1236.
    PMID: 29801406
    Background: Diffuse large B-cell lymphoma (DLBCL) with double expression of c-MYC and BCL2 protein is
    associated with dismal outcome after treatment with R-CHOP. Local data on disease burden and survival outcome in
    DLBCL is limited. We investigated the prognostic values of c-MYC/BCL2 protein co-expression and cell of origin
    subtypes using immunohistochemistry (IHC) and to determine their associations with multiethnic groups under
    resource limited setting. Methods: This was a retrospective study which recruited 104 patients in between June 2012
    and December 2015 for IHC review and analysis. Result: We demonstrated that patients with high International
    Prognostic Index (IPI) (score 3-5) and co-expression of c-MYC/BCL2 protein had significant inferior overall survival
    (OS) and event free survival (EFS) respectively (P<0.05). c-MYC/BCL2 protein co-expression was more common in
    non-germinal center B-cell (non-GCB) (P=0.048) and contributed to adverse prognosis in this group of patients (OS,
    P=0.004; EFS, P=0.005). In multivariate analysis, double-protein co-expression was a significant independent predictor
    of inferior outcome after adjusted for IPI and cell of origin subtypes (OS hazard ratio [HR], 2.11; 95% CI, 1.01 to 4.04;
    P=0.048; EFS HR, 2.31; 95% CI, 1.05 to 5.04; P=0.036). In addition, non-GCB subtype was more common than GCB
    in Malays (60% vs 40%, P=0.106) and Chinese (81.2% vs 18.8%, P=0.042). Indians had more DLBCL without c-MYC/
    BCL2 protein co-expression compared to double-protein positive cases (66.7% vs 33.3%, P=0.414). Otherwise, the
    prognostic impact of ethnicity on survival outcome was insignificant (P=0.961). Conclusion: c-MYC/BCL2 protein
    co-expression in non-GCB subtype constituted a unique group with extremely inferior outcome regardless of ethnicity.
    Gene expression profile (GEP) may possibly provide insights into the cause of discrepancies in DLBCL subtypes and
    protein expression among the multiethnic groups.
  15. Teo SY, Yew MY, Lee SY, Rathbone MJ, Gan SN, Coombes AGA
    J Pharm Sci, 2017 01;106(1):377-384.
    PMID: 27522920 DOI: 10.1016/j.xphs.2016.06.028
    Phenytoin-loaded alkyd nanoemulsions were prepared spontaneously using the phase inversion method from a mixture of novel biosourced alkyds and Tween 80 surfactant. Exposure of human adult keratinocytes (HaCaT cells) for 48 h to alkyd nanoemulsions producing phenytoin concentrations of 3.125-200 μg/mL resulted in relative cell viability readings using tetrazolium dye 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide of 100% confirming nontoxicity and suggesting cell proliferation activity. Phenytoin-loaded alkyd nanoemulsions generally resulted in higher mean cell viability compared with equivalent concentration of phenytoin solutions, suggesting that the nanoemulsions provided a controlled-release property that maintained the optimum phenytoin level for keratinocyte growth. HaCaT cell proliferation, measured by 5-bromo-2-deoxyuridine uptake, was found to increase following exposure to increasing phenytoin concentration from 25 to 50 μg/mL in solution or encapsulated in nanoemulsions but declined at a drug concentration of 100 μg/mL. An in vitro cell monolayer wound scratch assay revealed that phenytoin solution or nanoemulsions producing 50 μg/mL phenytoin concentration resulted in 75%-82% "scratch closure" after 36 h, similar to medium containing 10% fetal bovine serum as a cell growth promoter. These findings indicate that phenytoin-loaded alkyd nanoemulsions show potential for promoting topical wound healing through enhanced proliferation of epidermal cells.
  16. Tan MM, Ho WK, Yoon SY, Mariapun S, Hasan SN, Lee DS, et al.
    PLoS One, 2018;13(9):e0203469.
    PMID: 30216346 DOI: 10.1371/journal.pone.0203469
    BACKGROUND: Breast cancer risk factors have been examined extensively in Western setting and more developed Asian cities/countries. However, there are limited data on developing Asian countries. The purpose of this study was to examine breast cancer risk factors and the change of selected risk factors across birth cohorts in Malaysian women.

    METHODS: An unmatched hospital based case-control study was conducted from October 2002 to December 2016 in Selangor, Malaysia. A total of 3,683 cases and 3,980 controls were included in this study. Unconditional logistic regressions, adjusted for potential confounding factors, were conducted. The breast cancer risk factors were compared across four birth cohorts by ethnicity.

    RESULTS: Ever breastfed, longer breastfeeding duration, a higher soymilk and soy product intake, and a higher level of physical activity were associated with lower risk of breast cancer. Chinese had the lowest breastfeeding rate, shortest breastfeeding duration, lowest parity and highest age of first full term pregnancy.

    CONCLUSIONS: Our study shows that breastfeeding, soy intake and physical activity are modifiable risk factors for breast cancer. With the increasing incidence of breast cancer there is an urgent need to educate the women about lifestyle intervention they can take to reduce their breast cancer risk.

  17. Tan JS, Lee SY, Chew KW, Lam MK, Lim JW, Ho SH, et al.
    Bioengineered, 2020 12;11(1):116-129.
    PMID: 31909681 DOI: 10.1080/21655979.2020.1711626
    The richness of high-value bio-compounds derived from microalgae has made microalgae a promising and sustainable source of useful product. The present work starts with a review on the usage of open pond and photobioreactor in culturing various microalgae strains, followed by an in-depth evaluation on the common harvesting techniques used to collect microalgae from culture medium. The harvesting methods discussed include filtration, centrifugation, flocculation, and flotation. Additionally, the advanced extraction technologies using ionic liquids as extractive solvents applied to extract high-value bio-compounds such as lipids, carbohydrates, proteins, and other bioactive compounds from microalgae biomass are summarized and discussed. However, more work needs to be done to fully utilize the potential of microalgae biomass for the application in large-scale production of biofuels, food additives, and nutritive supplements.
  18. Syazwan SA, Lee SY, Sajap AS, Lau WH, Omar D, Mohamed R
    Biology (Basel), 2021 Mar 25;10(4).
    PMID: 33806225 DOI: 10.3390/biology10040263
    Metarhizium anisopliae (Metchnikoff) Sorokin, a pathogenic fungus to insects, infects the subterranean termite, Coptotermes curvignathus Holmgren, a devastating pest of plantation trees in the tropics. Electron microscopy and proteomics were used to investigate the infection and developmental process of M. anisopliae in C. curvignathus. Fungal infection was initiated by germ tube penetration through the host's cuticle as observed at 6 h post-inoculation (PI), after which it elongated into the host's integumental tissue. The colonization process continued as seen from dissemination of blastospores in the hemocoel at 96 h PI. At this time point, the emergent mycelia had mummified the host and forty-eight hours later, new conidia were dispersed on the termites' body surface. Meanwhile, hyphal bodies were observed in abundance in the intercellular space in the host's body. The proteomes of the pathogen and host were isolated separately using inoculated termite samples withdrawn at each PI-time point and analyzed in two-dimensional electrophoresis (2-DE) gels. Proteins expressed in termites showed evidence of being related to cell regulation and the immune response, while those expressed in M. anisopliae, to transportation and fungal virulence. This study provides new information on the interaction between termites and its entomopathogen, with potential utilization for developing future biopesticide to control the termite population.
  19. Sudmoon R, Kaewdaungdee S, Tanee T, Siripiyasing P, Ameamsri U, Syazwan SA, et al.
    Sci Rep, 2022 Nov 05;12(1):18810.
    PMID: 36335203 DOI: 10.1038/s41598-022-23639-2
    To expand the genomic information of Hypericaceae, particularly on Cratoxylum, we characterized seven novel complete plastid genomes (plastomes) of five Cratoxylum and two of its allied taxa, including C. arborescens, C. formosum subsp. formosum, C. formosum subsp. pruniflorum, C. maingayi, C. sumatranum, Hypericum hookerianum, and Triadenum breviflorum. For Cratoxylum, the plastomes ranged from 156,962 to 157,792 bp in length. Genomic structure and gene contents were observed in the five plastomes, and were comprised of 128-129 genes, which includes 83-84 protein-coding (CDS), 37 tRNA, and eight rRNA genes. The plastomes of H. hookerianum and T. breviflorum were 138,260 bp and 167,693 bp, respectively. A total of 110 and 127 genes included 72 and 82 CDS, 34 and 37 tRNA, as well as four and eight rRNA genes. The reconstruction of the phylogenetic trees using maximum likelihood (ML) and Bayesian inference (BI) trees based on the concatenated CDS and internal transcribed spacer (ITS) sequences that were analyzed separately have revealed the same topology structure at genus level; Cratoxylum is monophyletic. However, C. formosum subsp. pruniflorum was not clustered together with its origin, raising doubt that it should be treated as a distinct species, C. pruniflorum based on molecular evidence that was supported by morphological descriptions.
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