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A rare case of paediatric meningioma masquerading as intra-axial lesion

Tan LY, Tan AP

Med J Malaysia, 2018 12;73(6):439-440.
PMID: 30647227

Meningiomas are neoplasm arising from meningoepithelial cells, most commonly in the fifth to sixth decade of life. Meningiomas are rare in paediatric population, accounting for 0.4-4.1% of all paediatric tumours and less than 3% of paediatric brain tumours. However, meningiomas represent the most common dural based tumours in children. We describe a rare case of paediatric fibroblastic meningioma within the left middle cranial fossa masquerading as an intra-axial mass lesion. Our discussion will be centred on atypical features of paediatric meningiomas and differential diagnosis of extra-axial mass lesion in the paediatric population.
Fulltext Piper nigrum, Piper betle and Gnetum gnemon--natural food sources with anti-quorum sensing properties

Tan LY, Yin WF, Chan KG

Sensors (Basel), 2013;13(3):3975-85.
PMID: 23519352 DOI: 10.3390/s130303975

Various parts of Piper nigrum, Piper betle and Gnetum gnemon are used as food sources by Malaysians. The purpose of this study is to examine the anti-quorum sensing (anti-QS) properties of P. nigrum, P. betle and G. gnemon extracts. The hexane, chloroform and methanol extracts of these plants were assessed in bioassays involving Pseudomonas aeruginosa PA01, Escherichia coli [pSB401], E. coli [pSB1075] and Chromobacterium violaceum CV026. It was found that the extracts of these three plants have anti-QS ability. Interestingly, the hexane, chloroform and methanol extracts from P. betle showed the most potent anti-QS activity as judged by the bioassays. Since there is a variety of plants that serve as food sources in Malaysia that have yet to be tested for anti-QS activity, future work should focus on identification of these plants and isolation of the anti-QS compounds.
Fulltext Silencing quorum sensing through extracts of Melicope lunu-ankenda

Tan LY, Yin WF, Chan KG

Sensors (Basel), 2012;12(4):4339-51.
PMID: 22666033 DOI: 10.3390/s120404339

Quorum sensing regulates bacterial virulence determinants, therefore making it an interesting target to attenuate pathogens. In this work, we screened edible, endemic plants in Malaysia for anti-quorum sensing properties. Extracts from Melicope lunu-ankenda (Gaertn.) T. G. Hartley, a Malay garden salad, inhibited response of Chromobacterium violaceum CV026 to N-hexanoylhomoserine lactone, thus interfering with violacein production; reduced bioluminescence expression of E. coli [pSB401], disrupted pyocyanin synthesis, swarming motility and expression of lecA::lux of Pseudomonas aeruginosa PAO1. Although the chemical nature of the anti-QS compounds from M. lunu-ankenda is currently unknown, this study proves that endemic Malaysian plants could serve as leads in the search for anti-quorum sensing compounds.
Fulltext Hyperinflammatory Immune Response and COVID-19: A Double Edged Sword

Tan LY, Komarasamy TV, Rmt Balasubramaniam V

Front Immunol, 2021;12:742941.
PMID: 34659238 DOI: 10.3389/fimmu.2021.742941

The coronavirus disease-19 (COVID-19) elicited by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused devastating health, economic and social impact worldwide. Its clinical spectrum ranges from asymptomatic to respiratory failure and multi-organ failure or death. The pathogenesis of SARS-CoV-2 infection is attributed to a complex interplay between virus and host immune response. It involves activation of multiple inflammatory pathways leading to hyperinflammation and cytokine storm, resulting in tissue damage, acute respiratory distress syndrome (ARDS) and multi-organ failure. Accumulating evidence has raised concern over the long-term health effects of COVID-19. Importantly, the neuroinvasive potential of SARS-CoV-2 may have devastating consequences in the brain. This review provides a conceptual framework on how the virus tricks the host immune system to induce infection and cause severe disease. We also explore the key differences between mild and severe COVID-19 and its short- and long-term effects, particularly on the human brain.
Fulltext Factors related to successful return to work following multidisciplinary rehabilitation

Awang H, Tan LY, Mansor N, Tongkumchum P, Eso M

J Rehabil Med, 2017 Jun 28;49(6):520.
PMID: 28617522 DOI: 10.2340/16501977-2233

OBJECTIVE: To examine factors associated with successful return to work among participants in a Social Security Organisation Return To Work programme.
METHODS: Secondary data for 9,850 participants were obtained from the Social Security Organisation Return To Work database. The dependent variable was the Return To Work programme outcome, successful return to employment (same employer or different employer) or unsuccessful return. Logistic regression analysis with weighted sum contrasts was performed to assess the odds ratios with 95% confidence interval (95% CI) for successful return to employment across the various subgroups of participants.
RESULTS: Overall, 65.5% of participants successfully returned to employment, either with their former employers or with new employers. Successful return to employment was found to be significantly higher than the overall proportion among those participants who had had commuting accidents, followed by those who had had workplace accidents. Successful return to employment was also associated with injuries of the upper and lower limbs, employers who were interested in hiring disabled workers, motivation to participate in the programme, an intervention period of 3 months or less, age 29 years or younger, and male participants.
CONCLUSION: A structured multidisciplinary intervention programme provides a positive outcome in terms of returning to work. Related factors have various impacts on successful return to work.
Fulltext A one-pot, multicomponent reaction for the synthesis of novel 2-alkyl substituted 4-aminoimidazo[1,2-a][1,3,5]triazines

Lim FPL, Tan LY, Tiekink ERT, Dolzhenko AV

RSC Adv, 2018 Jun 08;8(38):21495-21504.
PMID: 35539915 DOI: 10.1039/c8ra03703e

A highly selective, one-pot, three-component synthesis of novel 2-alkyl-substituted 4-aminoimidazo[1,2-a][1,3,5]triazines has been developed. The scope of the method was explored in two dimensions, varying the structures of trialkyl orthoesters and 2-aminoimidazoles in their reactions with cyanamide. Conveniently performed under microwave irradiation, this method was also proved to be efficient under conventional heating. A library of 24 novel compounds was prepared in high purity using this multicomponent approach. Molecular and crystal structures of representative molecules were studied using X-ray crystallography.
DIFFERENTIALS IN SEXUAL AND REPRODUCTIVE HEALTH KNOWLEDGE AMONG EAST MALAYSIAN ADOLESCENTS

Awang H, Low WY, Tong WT, Tan LY, Cheah WL, Benedict Lasimbang H, et al.

J Biosoc Sci, 2019 03;51(2):282-291.
PMID: 29978769 DOI: 10.1017/S0021932018000214

The aim of this study was to assess the knowledge of East Malaysian adolescents on sexual and reproductive health issues. Data were collected in March-July 2015 from 2858 adolescents aged 13-18 years from selected East Malaysian secondary schools using a self-administered questionnaire. Twelve items relating to sexual and reproductive health were used to measure respondents' knowledge based on their responses 'True', 'False' or 'Don't know', with the proportion of correct answers being the variable of interest. Cronbach's alpha for the twelve items was 0.761 and the mean knowledge score was 6.8. While the majority of the respondents knew that a woman can get pregnant if she has sex with a man and that HIV and AIDS can be transmitted through sexual intercourse, knowledge about Malaysia's abortion laws, that a woman can get pregnant if she has sex only once and that people with sexually transmitted infections may look healthy was poor. Older respondents and those from urban schools reported significantly higher knowledge than younger respondents and those from rural schools, respectively. More emphasis should be given in schools to the specific topics for which low levels of sexual and reproductive health knowledge were found, with greater attention being given to younger adolescents and those in rural areas.
Fulltext Non-antibiotic quorum sensing inhibitors acting against N-acyl homoserine lactone synthase as druggable target

Chang CY, Krishnan T, Wang H, Chen Y, Yin WF, Chong YM, et al.

Sci Rep, 2014;4:7245.
PMID: 25430794 DOI: 10.1038/srep07245

N-acylhomoserine lactone (AHL)-based quorum sensing (QS) is important for the regulation of proteobacterial virulence determinants. Thus, the inhibition of AHL synthases offers non-antibiotics-based therapeutic potentials against QS-mediated bacterial infections. In this work, functional AHL synthases of Pseudomonas aeruginosa LasI and RhlI were heterologously expressed in an AHL-negative Escherichia coli followed by assessments on their AHLs production using AHL biosensors and high resolution liquid chromatography-mass spectrometry (LCMS). These AHL-producing E. coli served as tools for screening AHL synthase inhibitors. Based on a campaign of screening synthetic molecules and natural products using our approach, three strongest inhibitors namely are salicylic acid, tannic acid and trans-cinnamaldehyde have been identified. LCMS analysis further confirmed tannic acid and trans-cinnemaldehyde efficiently inhibited AHL production by RhlI. We further demonstrated the application of trans-cinnemaldehyde inhibiting Rhl QS system regulated pyocyanin production in P. aeruginosa up to 42.06%. Molecular docking analysis suggested that trans-cinnemaldehyde binds to the LasI and EsaI with known structures mainly interacting with their substrate binding sites. Our data suggested a new class of QS-inhibiting agents from natural products targeting AHL synthase and provided a potential approach for facilitating the discovery of anti-QS signal synthesis as basis of novel anti-infective approach.