Displaying publications 1 - 20 of 21 in total

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  1. Application of smartphone electrocardiogram
    Wong KC
    Med J Malaysia, 2021 07;76(4):565.
    PMID: 34305119
    No abstract provided.
  2. Fulltext Are doctors in the university-based primary care clinic more evidence-based?
    Khoo EM, Teng CL, Wong KC
    Med J Malaysia, 2004 Mar;59(1):129.
    PMID: 15535352
  3. Fulltext Benign persistent pneumoperitoneum in systemic sclerosis
    Wang CL, Wang F, Wong KC, Jeyamalar R
    Singapore Med J, 1993 Dec;34(6):563-4.
    PMID: 8153727
    We describe a 50-year-old Chinese woman who had severe gastrointestinal manifestations from systemic sclerosis complicated by spontaneous pneumoperitoneum in the absence of either visceral perforation or pneumatosis cystoides intestinalis. This is a rare complication of systemic sclerosis; only four other cases have been reported. Recognition of this condition is important so as to avoid unnecessary surgery.
  4. New cholinesterase inhibitors from Garcinia atroviridis
    Tan WN, Khairuddean M, Wong KC, Khaw KY, Vikneswaran M
    Fitoterapia, 2014 Sep;97:261-7.
    PMID: 24924287 DOI: 10.1016/j.fitote.2014.06.003
    A triflavanone, Garcineflavanone A (1) and a biflavonol, Garcineflavonol A (2) have been isolated from the stem bark of Garcinia atroviridis (Clusiaceae), collected in Peninsular Malaysia. Their structures were established using one and two-dimensional NMR, UV, IR and mass spectrometry and evaluated in vitro for their acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) enzymes inhibitory activity. Molecular docking studies of the isolated compounds were performed using docking procedure of AutoDock to disclose the binding interaction and orientation of these molecules into the active site gorge.
  5. Chemical constituents and antibacterial activity of Melastoma malabathricum L
    Wong KC, Hag Ali DM, Boey PL
    Nat Prod Res, 2012;26(7):609-18.
    PMID: 21834640 DOI: 10.1080/14786419.2010.538395
    The aqueous methanolic extracts of Melastoma malabathricum L. exhibited antibacterial activity when assayed against seven microorganisms by the agar diffusion method. Solvent fractionation afforded active chloroform and ethyl acetate fractions from the leaves and the flowers, respectively. A phytochemical study resulted in the identification of ursolic acid (1), 2α-hydroxyursolic acid (2), asiatic acid (3), β-sitosterol 3-O-β-D-glucopyranoside (4) and the glycolipid glycerol 1,2-dilinolenyl-3-O-β-D-galactopyanoside (5) from the chloroform fraction. Kaempferol (6), kaempferol 3-O-α-L-rhamnopyranoside (7), kaempferol 3-O-β-D-glucopyranoside (8), kaempferol 3-O-β-D-galactopyranoside (9), kaempferol 3-O-(2″,6″-di-O-E-p-coumaryl)-β-D-galactopyranoside (10), quercetin (11) and ellagic acid (12) were found in the ethyl acetate fraction. The structures of these compounds were determined by chemical and spectral analyses. Compounds 1-4, the flavonols (6 and 11) and ellagic acid (12) were found to be active against some of the tested microorganisms, while the kaempferol 3-O-glycosides (7-9) did not show any activity, indicating the role of the free 3-OH for antibacterial activity. Addition of p-coumaryl groups results in mild activity for 10 against Staphylococcus aureus and Bacillus cereus. Compounds 2-5, 7 and 9-12 are reported for the first time from M. malabathricum. Compound 10 is rare, being reported only once before from a plant, without assignment of the double bond geometry in the p-coumaryl moiety.
  6. Flavonoids from Blumea balsamifera
    Ali DM, Wong KC, Lim PK
    Fitoterapia, 2005 Jan;76(1):128-30.
    PMID: 15664477
    3,4',5-Trihydroxy-3',7-dimethoxyflavanone was isolated from the ligroin extract of the leaves of Blumea balsamifera, while the acetone extract yielded 3',4',5-trihydroxy-7-methoxyflavanone and a new biflavonoid identifed as 3-O-7''-biluteolin (1). The isolation of 1 is significant since a biflavonoid with a C-O-C linkage of the type [I-3-O-II-7] has not been previously reported from a plant.
  7. Factors relating to adolescent suicidal behavior: a cross-sectional Malaysian school survey
    Chen PC, Lee LK, Wong KC, Kaur J
    J Adolesc Health, 2005 Oct;37(4):337.
    PMID: 16182146
    This study was undertaken to examine factors relating to adolescent suicide behavior.
  8. New compounds with antimicrobial activities from Elaeodendron buchananii stem bark
    Odak JA, Manguro LOA, Wong KC
    J Asian Nat Prod Res, 2018 Jun;20(6):510-524.
    PMID: 29338355 DOI: 10.1080/10286020.2017.1420648
    The plant species Elaeodendron buchananii Loes is widely used in folklore medicine to manage microbial infections in Kenya. Previous studies on the plant fruits and root bark revealed the presence of steroids and terpenoids. The present phytochemical analysis of the plant stem bark has led to the isolation of four new triterpenes characterized as methyl 3β-acetoxy-11α, 19α, 28-trihydroxyurs-12-en-23-oic acid (1), 3β, 11α, 19α-trihydroxyurs-12-en-23, 28-dioic acid (2), 3β-acetoxy-19α, 23, 28-trihydroxyurs-12-ene (3) and 3-oxo-19α, 28-dihydroxyurs-12-en-24-oic acid (4), together with ten known ones (5-14), whose structures were elucidated using spectroscopic techniques. The isolate canophyllol (8) showed promising antibacterial activity against N. meningitides with MIC value of 31.25 μg/ml.
  9. Fulltext Popliteus Tendon Injury: A Rare Cause of Acute Locked Knee
    Wong KC, Mohamad N, Md Yusoff BAH
    Cureus, 2023 May;15(5):e38655.
    PMID: 37288232 DOI: 10.7759/cureus.38655
    The acute locked knee is a common presentation of meniscal tears or other intra-articular injuries. However, a popliteus tendon tear, an uncommon cause of acute locked knee, is often overlooked as a possible diagnosis. Here, we present the case of a 29-year-old male who experienced an acute locked knee following a sports injury. An arthroscopic examination revealed an intrasubstance tear in the popliteus tendon and a complete anterior cruciate ligament tear, while the menisci remained intact. Due to the extension lag caused by the popliteus tendon tear, the anterior cruciate ligament reconstruction was postponed. The patient then underwent a course of physiotherapy before the anterior cruciate ligament reconstruction and eventually achieved full knee extension after six weeks. Further surgical intervention was then performed to address the ligament injury. Our case highlights the importance of considering a popliteus tendon tear as a possible cause of an acute locked knee. Proper diagnosis and management are crucial for achieving optimal outcomes for patients with an acute locked knee and concomitant ligamentous injury.
  10. A new sesquiterpenoid from the rhizomes of Homalomena sagittifolia
    Wong KC, Hamid A, Eldeen IM, Asmawi MZ, Baharuddin S, Abdillahi HS, et al.
    Nat Prod Res, 2012;26(9):850-8.
    PMID: 21999629 DOI: 10.1080/14786419.2010.551770
    A new sesquiterpenoid, 1α,4β,7β-eudesmanetriol (1), was isolated together with the known compounds 1β,4β,7β-eudesmanetriol (2) and oplopanone (3) from the rhizomes of Homalomena sagittifolia. The structures of these compounds were determined by extensive spectral analyses. The compounds 1 and 2 inhibited growth of Pseudomonas stutzeri with a MIC value of 117 µM when evaluated for antibacterial activity using the minimum concentration assay. Both these compounds showed remarkable activities against acetylcholinesterase enzyme with IC(50) values ranging between 25 and 26 µM. The isolation of these sesquiterpenoids and their biological activities observed in this study support the reported traditional uses of H. sagittifolia for the treatment of microbial related diseases and central nervous system disorders.
  11. Antioxidant compounds from the stem bark of Garcinia atroviridis
    Tan WN, Khairuddean M, Wong KC, Tong WY, Ibrahim D
    J Asian Nat Prod Res, 2016 Aug;18(8):804-11.
    PMID: 26999039 DOI: 10.1080/10286020.2016.1160071
    A new xanthone, namely garcinexanthone G (1), along with eight known compounds, stigmasta-5,22-dien-3β-ol (2), stigmasta-5,22-dien-3-O-β-glucopyranoside (3), 3β-acetoxy-11α,12α-epoxyoleanan-28,13β-olide (4), 2,6-dimethoxy-p-benzoquinone (5), 1,3,5-trihydroxy-2-methoxyxanthone (6), 1,3,7-trihydroxyxanthone (7), kaempferol (8) and quercetin (9), were isolated from the stem bark of Garcinia atroviridis. Their structures were elucidated based on spectroscopic methods including nuclear magnetic resonance (NMR-1D and 2D), UV, IR, and mass spectrometry. All the isolated compounds were evaluated for their antioxidant properties based on the DPPH radical scavenging activities. Results showed that 1,3,7-trihydroxyxanthone and quercetin showed significant antioxidant activities with EC50 values of 16.20 and 12.68 μg/ml, respectively, as compared to the control, ascorbic acid (7.4 μg/ml).
  12. Melatonin improves cognitive behavior, oxidative stress, and metabolism in tumor-prone lethal giant larvae mutant of Drosophila melanogaster
    Wong KC, Sankaran S, Jayapalan JJ, Subramanian P, Abdul-Rahman PS
    Arch Insect Biochem Physiol, 2021 May;107(1):e21785.
    PMID: 33818826 DOI: 10.1002/arch.21785
    Mutant lethal giant larvae (lgl) flies (Drosophila melanogaster) are known to develop epithelial tumors with invasive characteristics. The present study has been conducted to investigate the influence of melatonin (0.025 mM) on behavioral responses of lgl mutant flies as well as on biochemical indices (redox homeostasis, carbohydrate and lipid metabolism, transaminases, and minerals) in hemolymph, and head and intestinal tissues. Behavioral abnormalities were quantitatively observed in lgl flies but were found normalized among melatonin-treated lgl flies. Significantly decreased levels of lipid peroxidation products and antioxidants involved in redox homeostasis were observed in hemolymph and tissues of lgl flies, but had restored close to normalcy in melatonin-treated flies. Carbohydrates including glucose, trehalose, and glycogen were decreased and increased in the hemolymph and tissues of lgl and melatonin-treated lgl flies, respectively. Key enzymes of carbohydrate metabolism showed a significant increment in their levels in lgl mutants but had restored close to wild-type baseline levels in melatonin-treated flies. Variables of lipid metabolism showed significantly inverse levels in hemolymph and tissues of lgl flies, while normalization of most of these variables was observed in melatonin-treated mutants. Lipase, chitinase, transaminases, and alkaline phosphatase showed an increment in their activities and minerals exhibited decrement in lgl flies; reversal of changes was observed under melatonin treatment. The impairment of cognition, disturbance of redox homeostasis and metabolic reprogramming in lgl flies, and restoration of normalcy in all these cellular and behavioral processes indicate that melatonin could act as oncostatic and cytoprotective agents in Drosophila.
  13. Experimental Study on Plasmodium knowlesi Normocyte Binding Protein Xa Region II (PkNBPXaII) for Erythrocyte Binding
    Wong KC, Lai MY, De Silva JR, Cheong FW, Fong MY, Lau YL
    Trop Biomed, 2021 Jun 01;38(2):143-148.
    PMID: 34172703 DOI: 10.47665/tb.38.2.051
    Normocyte binding protein Xa (NBPXa) has been implied to play a significant role in parasite invasion of human erythrocytes. Previous phylogenetic studies have reported the existence of three types of NBPXa for Plasmodium knowlesi (PkNBPXa). PkNBPXa region II (PkNBPXaII) of type 1, type 2 and type 3 were expressed on mammalian cell surface and interacted with human and macaque (Macaca fascicularis) erythrocytes. The binding activities of PkNBPXaII towards human and macaque erythrocytes were evaluated using erythrocyte-binding assay (EBA). Three parameters were evaluated to achieve the optimal protein expression of PkNBPXaII and erythrocyte binding activity in EBA: types of mammalian cells, post transfection time and erythrocyte incubation time. COS-7, HEK-293, and CHO-K1 cells showed successful expression of PkNBPXaII, despite the protein expression is weak compared to the positive control. COS-7 was used in EBA. All three types of PkNBPXaII showed rosette formation with macaque erythrocytes but not with human erythrocytes. Future studies to enhance the PkNBPXaII expression on surface of mammalian cells is indeed needed in order to elucidate the specific role of PkNBPXaII in erythrocytes invasion.
  14. Label-free quantitative mass spectrometry analysis of the circadian proteome of Drosophila melanogaster lethal giant larvae mutants reveals potential therapeutic effects of melatonin
    Wong KC, Jayapalan JJ, Subramanian P, Ismail MN, Abdul-Rahman PS
    Arch Insect Biochem Physiol, 2023 Mar 13.
    PMID: 36915983 DOI: 10.1002/arch.22008
    Mutation in the Drosophila melanogaster lethal giant larvae (lgl), a tumor suppressor gene with a well-established role in cellular polarity, is known to results in massive cellular proliferation and neoplastic outgrowths. Although the tumorigenic properties of lgl mutant have been previously studied, however, little is known about its consequences on the proteome. In this study, mass spectrometry-based label-free quantitative proteomics was employed to investigate the changes in the head and intestinal tissues proteins of Drosophila melanogaster, due to lgl mutation and following treatment with melatonin. Additionally, to uncover the time-influenced variations in the proteome during tumorigenesis and melatonin treatment, the rhythmic expression of proteins was also investigated at 6-h intervals within 24-h clock. Together, the present study has identified 434 proteins of altered expressions (p 
  15. Fulltext Concomitant Ulnar Styloid Fractures in Distal Radius Osteosynthesis Does Not Impact Radiographic Outcomes, Ulnar Sided Symptoms and Patient Outcomes
    Wong KC, Wu M, Zai Q, Wong MK, Howe TS, Koh S, et al.
    Malays Orthop J, 2023 Mar;17(1):142-148.
    PMID: 37064641 DOI: 10.5704/MOJ.2303.017
    INTRODUCTION: Current literature reports varied significance of ulnar styloid fractures (USF) associated with distal radius fractures. Our study assesses the role of ulnar styloid fractures and fragment size in surgically managed distal radius fractures.

    MATERIALS AND METHODS: We reviewed patients who underwent surgical fixation of distal radius fractures between January 2004 to June 2006. Patients were divided into those with (Group 1) and without (Group 0) USFs. Post-operative radiographic parameters, clinical outcomes and overall wrist function were analysed. Outcomes included ulnar-sided wrist pain, extensor carpi ulnaris (ECU) tendinitis, triangular fibrocartilage complex (TFCC) grind test, distal radioulnar joint (DRUJ) instability and pain. Overall wrist function was assessed with range of motion and Disabilities of the Arm, Shoulder and Hand (DASH) score.

    RESULTS: Our study cohort included 31 males and 23 females, and 38.9% of these patients had concomitant USFs. There was no difference in terms of demographic data and fracture configuration between groups. Radiographic parameters were similar, except for palmar tilt, which was significantly higher in Group 1 (4.6º vs 9.4º, p=0.047). At 24 months, there were no differences in clinical outcomes and overall wrist function. A sub-group analysis showed that mean USF fragment size was larger in patients with a positive TFCC grind test (3.9mm vs 7.3mm, p=0.033).

    CONCLUSION: The presence of USFs in surgically managed distal radius fractures does not compromise clinical and functional outcome. Similarly, the size of USFs does not impact clinical and functional outcome but is associated with the presence of a positive TFCC grind test.

  16. Tuberculosis screening in a novel substance abuse treatment center in Malaysia: implications for a comprehensive approach for integrated care
    Al-Darraji HA, Wong KC, Yeow DG, Fu JJ, Loeliger K, Paiji C, et al.
    J Subst Abuse Treat, 2014 Feb;46(2):144-9.
    PMID: 24074846 DOI: 10.1016/j.jsat.2013.08.023
    People who use drugs (PWUD) represent a key high risk group for tuberculosis (TB). The prevalence of both latent TB infection (LTBI) and active disease in drug treatment centers in Malaysia is unknown. A cross-sectional convenience survey was conducted to assess the prevalence and correlates of LTBI among attendees at a recently created voluntary drug treatment center using a standardized questionnaire and tuberculin skin testing (TST). Participants (N=196) were mostly men (95%), under 40 (median age=36 years) and reported heroin use immediately before treatment entry (75%). Positive TST prevalence was 86.7%. Nine (4.6%) participants were HIV-infected. Previous arrest/incarcerations (AOR=1.1 for every entry, p<0.05) and not being HIV-infected (AOR=6.04, p=0.03) were significantly associated with TST positivity. There is an urgent need to establish TB screening and treatment programs in substance abuse treatment centers and to tailor service delivery to the complex treatment needs of patients with multiple medical and psychiatric co-morbidities.
  17. Tailoring the CO2-selectivity of interfacial polymerized thin film nanocomposite membrane via the barrier effect of functionalized boron nitride
    Wong KC, Goh PS, Suzaimi ND, Ng ZC, Ismail AF, Jiang X, et al.
    J Colloid Interface Sci, 2021 Dec;603:810-821.
    PMID: 34237599 DOI: 10.1016/j.jcis.2021.06.156
    Membrane-based separation is an appealing solution to mitigate CO2 emission sustainably due to its energy efficiency and environmental friendliness. Attributed to its excellent separation endowed by nanomaterial incorporation, nanocomposite membrane is rigorously developed. This study explored the feasibility of boron nitride (BN) embedment and changes to formation mechanism of ultrathin selective layer of thin film nanocomposite (TFN) are investigated. The effects of amine-functionalization on nanosheet-polymer interaction and CO2 separation performance are also identified. Participation of nanosheets during interfacial polymerization reduced the crosslinking of selective layer, hence, improved TFN permeance while the formation of contorted diffusion paths by the nanosheets favors transport of small gases. Amine-functionalization enhanced the nanosheet-polymer interaction and elevated the membrane affinity towards CO2 which led to enhanced CO2 selectivity. The best TFN prepared in this study exhibited 37% and 20% increment in permeability and selectivity, respectively with respect to neat thin film composite (TFC). It is found that the CO2 separation performance of BN incorporated TFN is on par with many non-porous nanosheet-incorporated TFNs reported in literatures. The transport and barrier effects of BN and functionalized BN are discussed in detail to provide further insights into the development of commercially attractive CO2 selective TFN membranes.
  18. Fulltext Development of Ultrahigh Permeance Hollow Fiber Membranes via Simple Surface Coating for CO2/CH4 Separation
    Said N, Wong KC, Lau WJ, Khoo YS, Yeong YF, Othman NH, et al.
    Molecules, 2022 Dec 01;27(23).
    PMID: 36500475 DOI: 10.3390/molecules27238381
    Most researchers focused on developing highly selective membranes for CO2/CH4 separation, but their developed membranes often suffered from low permeance. In this present work, we aimed to develop an ultrahigh permeance membrane using a simple coating technique to overcome the trade-off between membrane permeance and selectivity. A commercial silicone membrane with superior permeance but low CO2/CH4 selectivity (in the range of 2-3) was selected as the host for surface modification. Our results revealed that out of the three silane agents tested, only tetraethyl orthosilicate (TEOS) improved the control membrane's permeance and selectivity. This can be due to its short structural chain and better compatibility with the silicone substrate. Further investigation revealed that higher CO2 permeance and selectivity could be attained by coating the membrane with two layers of TEOS. The surface integrity of the TEOS-coated membrane was further improved when an additional polyether block amide (Pebax) layer was established atop the TEOS layer. This additional layer sealed the pin holes of the TEOS layer and enhanced the resultant membrane's performance, achieving CO2/CH4 selectivity of ~19 at CO2 permeance of ~2.3 × 105 barrer. This performance placed our developed membrane to surpass the 2008 Robeson Upper Boundary.
  19. Fulltext Strategies in Forward Osmosis Membrane Substrate Fabrication and Modification: A Review
    Suzaimi ND, Goh PS, Ismail AF, Mamah SC, Malek NANN, Lim JW, et al.
    Membranes (Basel), 2020 Nov 07;10(11).
    PMID: 33171847 DOI: 10.3390/membranes10110332
    Forward osmosis (FO) has been recognized as the preferred alternative membrane-based separation technology for conventional water treatment technologies due to its high energy efficiency and promising separation performances. FO has been widely explored in the fields of wastewater treatment, desalination, food industry and bio-products, and energy generation. The substrate of the typically used FO thin film composite membranes serves as a support for selective layer formation and can significantly affect the structural and physicochemical properties of the resultant selective layer. This signifies the importance of substrate exploration to fine-tune proper fabrication and modification in obtaining optimized substrate structure with regards to thickness, tortuosity, and porosity on the two sides. The ultimate goal of substrate modification is to obtain a thin and highly selective membrane with enhanced hydrophilicity, antifouling propensity, as well as long duration stability. This review focuses on the various strategies used for FO membrane substrate fabrication and modification. An overview of FO membranes is first presented. The extant strategies applied in FO membrane substrate fabrications and modifications in addition to efforts made to mitigate membrane fouling are extensively reviewed. Lastly, the future perspective regarding the strategies on different FO substrate layers in water treatment are highlighted.
  20. Phyto-fabricated ZnO nanoparticles for anticancer, photo-antimicrobial effect on carbapenem-resistant/sensitive Pseudomonas aeruginosa and removal of tetracycline
    Venkatraman G, Mohan PS, Mashghan MM, Wong KC, Abdul-Rahman PS, Vellasamy KM, et al.
    Bioprocess Biosyst Eng, 2024 Mar 16.
    PMID: 38491194 DOI: 10.1007/s00449-024-02984-8
    Alternanthera sessilis (AS) leaf extract was used to synthesize zinc oxide nanoparticles (ZnO NPs). Bioanalytical characterization techniques such as X-ray diffraction (XRD) and field emission scanning electron microscope (FESEM) confirmed the formation of crystalline ZnO NPs with average sizes of 40 nm. The AS-ZnO NPs antimicrobial activity was analyzed under dark (D) and white light (WL) conditions. The improved antimicrobial activity was observed against Escherichia coli, Staphylococcus aureus and Bacillus subtilis at the minimal inhibitory concentration (MIC) of 125 and 62.5 µg/mL under WL than the D at 125 and 250 µg/mL for E. coli, B. subtilis, and Pseudomonas aeruginosa, respectively. In contrast, the growth of P. aeruginosa and S. aureus was not completely inhibited until 1 mg/mL AS-ZnO NPs under WL and D. Similarly, AS-ZnO NPs displayed a weaker inhibitory effect against carbapenem-sensitive P. aeruginosa (CSPA) and carbapenem-resistant P. aeruginosa (CRPA) strains of PAC023, PAC041 and PAC032, PAC045 under D. Interestingly, the distinct inhibitory effect was recorded against CSPA PAC041 and CRPA PAC032 in which the bacteria growth was inhibited 99.9% at 250, 500 µg/mL under WL. The cytotoxicity results suggested AS-ZnO NPs demonstrated higher toxicity to MCF-7 breast cancer cells than the RAW264.7 macrophage cells. Further, AS-ZnO NPs exhibited higher catalytic potential against tetracycline hydrochloride (TC-H) degradation at 65.6% and 60.8% under WL than the dark at 59.35% and 48.6% within 120 min. Therefore, AS-ZnO NPs can be used to design a photo-improved antimicrobial formulation and environmental catalyst for removing TC-H from wastewater.
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