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  1. Fulltext Treatment of landfill leachate using ASBR combined with zeolite adsorption technology
    Lim CK, Seow TW, Neoh CH, Md Nor MH, Ibrahim Z, Ware I, et al.
    3 Biotech, 2016 Dec;6(2):195.
    PMID: 28330267 DOI: 10.1007/s13205-016-0513-8
    Sanitary landfilling is the most common way to dispose solid urban waste; however, improper landfill management may pose serious environmental threats through discharge of high strength polluted wastewater also known as leachate. The treatment of landfill leachate to fully reduce the negative impact on the environment, is nowadays a challenge. In this study, an aerobic sequencing batch reactor (ASBR) was proposed for the treatment of locally obtained real landfill leachate with initial ammoniacal nitrogen and chemical oxygen demand (COD) concentration of 1800 and 3200 mg/L, respectively. ASBR could remove 65 % of ammoniacal nitrogen and 30 % of COD during seven days of treatment time. Thereafter, an effective adsorbent, i.e., zeolite was used as a secondary treatment step for polishing the ammoniacal nitrogen and COD content that is present in leachate. The results obtained are promising where the adsorption of leachate by zeolite further enhanced the removal of ammoniacal nitrogen and COD up to 96 and 43 %, respectively. Furthermore, this combined biological-physical treatment system was able to remove heavy metals, i.e. aluminium, vanadium, chromium, magnesium, cuprum and plumbum significantly. These results demonstrate that combined ASBR and zeolite adsorption is a feasible technique for the treatment of landfill leachate, even considering this effluent's high resistance to treatment.
  2. Total cell pooling in vitro: an effective isolation method for bone marrow-derived multipotent stromal cells
    Wee AS, Lim CK, Merican AM, Ahmad TS, Kamarul T
    In Vitro Cell Dev Biol Anim, 2013 Jun;49(6):424-32.
    PMID: 23708918 DOI: 10.1007/s11626-013-9626-0
    In vitro cellular proliferation and the ability to undergo multilineage differentiation make bone marrow-derived multipotent stromal cells (MSCs) potentially useful for clinical applications. Several methods have been described to isolate a homogenous bone marrow-derived MSCs population; however, none has been proven most effective, mainly due to their effects on proliferation and differentiation capability of the isolated cells. It is hypothesized that our newly established total cell pooling method may provide a better alternative as compared to the standard isolation method (density gradient centrifugation method). For the total cell pooling method, MSCs were isolated from rabbit bone marrow and were subsequently cultured in the growth medium without further separation as in the standard isolation method. The total cell pooling method was 65 min faster than the standard isolation method in completing cell isolation. Nevertheless, both methods did not differ significantly in the number of primary viable cells and population doubling time in the cultures (p > 0.05). The isolated cells from both methods expressed CD29 and CD44 markers, but not CD45 markers. Furthermore, they displayed multilineage differentiation characteristics of chondroblasts, osteoblasts, and adipocytes. In conclusion, both methods provide similar efficiency in the isolation of rabbit bone marrow-derived MSCs; however, the total cell pooling method is technically simpler and more cost effective than the standard isolation method.
  3. The Cytokines CXCL10 and CCL2 and the Kynurenine Metabolite Anthranilic Acid Accurately Predict Patients at Risk of Developing Dengue With Warning Signs
    Jusof FF, Lim CK, Aziz FN, Soe HJ, Raju CS, Sekaran SD, et al.
    J Infect Dis, 2022 Nov 28;226(11):1964-1973.
    PMID: 35767283 DOI: 10.1093/infdis/jiac273
    BACKGROUND: The resolution or aggravation of dengue infection depends on the patient's immune response during the critical phase. Cytokines released by immune cells increase with the worsening severity of dengue infections. Cytokines activate the kynurenine pathway (KP) and the extent of KP activation then influences disease severity.

    METHODS: KP metabolites and cytokines in plasma samples of patients with dengue infection (dengue without warning signs [DWS-], dengue with warning signs [DWS+], or severe dengue) were analyzed. Cytokines (interferon gamma [IFN-ɣ], tumor necrosis factor, interleukin 6, CXCL10/interferon-inducile protein 10 [IP-10], interleukin 18 [IL-18], CCL2/monocyte chemoattractant protein-1 [MCP-1], and CCL4/macrophage inflammatory protein-1beta [MIP-1β] were assessed by a Human Luminex Screening Assay, while KP metabolites (tryptophan, kynurenine, anthranilic acid [AA], picolinic acid, and quinolinic acid) were assessed by ultra-high-performance liquid chromatography and Gas Chromatography Mass Spectrophotometry [GCMS] assays.

    RESULTS: Patients with DWS+ had increased activation of the KP where kynurenine-tryptophan ratio, anthranilic acid, and picolinic acid were elevated. These patients also had higher levels of the cytokines IFN-ɣ, CXCL10, CCL4, and IL-18 than those with DWS-. Further receiver operating characteristic analysis identified 3 prognostic biomarker candidates, CXCL10, CCL2, and AA, which predicted patients with higher risks of developing DWS+ with an accuracy of 97%.

    CONCLUSIONS: The data suggest a unique biochemical signature in patients with DWS+. CXCL10 and CCL2 together with AA are potential prognostic biomarkers that discern patients with higher risk of developing DWS+ at earlier stages of infection.

  4. TGF-β1 and -β3 for Mesenchymal Stem Cells Chondrogenic Differentiation on Poly (Vinyl Alcohol)-Chitosan-Poly (Ethylene Glycol) Scaffold
    Wee AS, Lim CK, Tan SL, Ahmad TS, Kamarul T
    Tissue Eng Part C Methods, 2022 10;28(10):501-510.
    PMID: 36082992 DOI: 10.1089/ten.TEC.2022.0112
    Transforming growth factor-beta 1 (TGF-β1) has been reported to promote chondrogenic differentiation and proliferation in the multipotent stromal cell (MSCs), and the transforming growth factor-beta 3 (TGF-β3) tends to be exclusively in promoting cell differentiation alone. The objective of this study was to determine the effect of TGF-β1 and -β3 on the MSCs chondrogenic differentiation on the poly (vinyl alcohol)-chitosan-poly (ethylene glycol) (PVA-NOCC-PEG) scaffold, compared with that of monolayer and pellet cultures. In this study, P2 rabbit bone marrow-derived MSCs were seeded either on the untreated six-well plate (for monolayer culture) or onto the PVA-NOCC-PEG scaffold or cultured as a pellet culture. The cultures were maintained in a chemically defined serum-free medium supplemented with 10 ng/mL of either TGF-β1 or TGF-β3. Cell viability assay, biochemical assay, and real-time polymerase chain reaction were performed to determine the net effect of cell proliferation and chondrogenic differentiation of each of the growth factors. The results showed that the PVA-NOCC-PEG scaffold enhanced MSCs cell proliferation from day 12 to 30 (p  0.05). In terms of chondrogenic differentiation, the PVA-NOCC-PEG scaffold augmented the GAGs secretion in MSCs and the mRNA expression levels of Sox9, Col2a1, Acan, and Comp were elevated (p  0.05). In conclusion, TGF-β1 and TGF-β3 enhanced the chondrogenic differentiation of MSCs seeded on the PVA-NOCC-PEG scaffold; however, there was no significant difference between the effect of TGF-β1 and TGF-β3. Impact statement Transforming growth factor-beta (TGF-β) superfamily members is a key requirement for the in vitro chondrogenic differentiation of mesenchymal stem cells (MSCs). In this study, the effects of TGF-β1 and -β3 on MSC chondrogenic differentiation and proliferation on a novel three-dimensional scaffold, the poly(vinyl alcohol)-chitosan-poly(ethylene glycol) (PVA-NOCC-PEG) scaffold, was evaluated. In this study, the results showed both TGF-β1 and TGF-β3 can enhance the chondrogenic differentiation of MSCs seeded on the PVA-NOCC-PEG scaffold.
  5. Synergistic effects of chitosan scaffold and TGFβ1 on the proliferation and osteogenic differentiation of dental pulp stem cells derived from human exfoliated deciduous teeth
    Farea M, Husein A, Halim AS, Abdullah NA, Mokhtar KI, Lim CK, et al.
    Arch Oral Biol, 2014 Dec;59(12):1400-11.
    PMID: 25222336 DOI: 10.1016/j.archoralbio.2014.08.015
    Multipotent stem cells derived from human exfoliated deciduous teeth (SHED) represent a promising cell source for tissue regeneration. In the present study we decided to test the inductive effect of chitosan and transforming growth factor-β1 (TGFβ1) as a scaffold/factor combination on SHED proliferation and osteogenic differentiation.
  6. Supermacroporous poly(vinyl alcohol)-carboxylmethyl chitosan-poly(ethylene glycol) scaffold: an in vitro and in vivo pre-assessments for cartilage tissue engineering
    Lee SY, Wee AS, Lim CK, Abbas AA, Selvaratnam L, Merican AM, et al.
    J Mater Sci Mater Med, 2013 Jun;24(6):1561-70.
    PMID: 23512151 DOI: 10.1007/s10856-013-4907-4
    This study aims to pre-assess the in vitro and in vivo biocompatibility of poly(vinyl alcohol)-carboxylmethyl-chitosan-poly(ethylene glycol) (PCP) scaffold. PCP was lyophilised to create supermacroporous structures. 3-(4, 5-dimethyl-thiazol-2yl)-2, 5-diphenyltetrazolium bromide (MTT) assay and immunohistochemistry (IHC) were used to evaluate the effectiveness of PCP scaffolds for chondrocytes attachment and proliferation. The ultrastructural was assessed using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Extracellular matrix (ECM) formation was evaluated using collagen type-II staining, glycosaminoglycan (GAG) and collagen assays. Histological analysis was conducted on 3-week implanted Sprague-Dawley rats. The MTT, IHC, SEM and TEM analyses confirm that PCP scaffolds promoted cell attachment and proliferation in vitro. The chondrocyte-PCP constructs secreted GAG and collagen type-II, both increased significantly from day-14 to day-28 (P 
  7. Smart Home-based IoT for Real-time and Secure Remote Health Monitoring of Triage and Priority System using Body Sensors: Multi-driven Systematic Review
    Talal M, Zaidan AA, Zaidan BB, Albahri AS, Alamoodi AH, Albahri OS, et al.
    J Med Syst, 2019 Jan 15;43(3):42.
    PMID: 30648217 DOI: 10.1007/s10916-019-1158-z
    The Internet of Things (IoT) has been identified in various applications across different domains, such as in the healthcare sector. IoT has also been recognised for its revolution in reshaping modern healthcare with aspiring wide range prospects, including economical, technological and social. This study aims to establish IoT-based smart home security solutions for real-time health monitoring technologies in telemedicine architecture. A multilayer taxonomy is driven and conducted in this study. In the first layer, a comprehensive analysis on telemedicine, which focuses on the client and server sides, shows that other studies associated with IoT-based smart home applications have several limitations that remain unaddressed. Particularly, remote patient monitoring in healthcare applications presents various facilities and benefits by adopting IoT-based smart home technologies without compromising the security requirements and potentially large number of risks. An extensive search is conducted to identify articles that handle these issues, related applications are comprehensively reviewed and a coherent taxonomy for these articles is established. A total number of (n = 3064) are gathered between 2007 and 2017 for most reliable databases, such as ScienceDirect, Web of Science and Institute of Electrical and Electronic Engineer Xplore databases. Then, the articles based on IoT studies that are associated with telemedicine applications are filtered. Nine articles are selected and classified into two categories. The first category, which accounts for 22.22% (n = 2/9), includes surveys on telemedicine articles and their applications. The second category, which accounts for 77.78% (n = 7/9), includes articles on the client and server sides of telemedicine architecture. The collected studies reveal the essential requirement in constructing another taxonomy layer and review IoT-based smart home security studies. Therefore, IoT-based smart home security features are introduced and analysed in the second layer. The security of smart home design based on IoT applications is an aspect that represents a crucial matter for general occupants of smart homes, in which studies are required to provide a better solution with patient security, privacy protection and security of users' entities from being stolen or compromised. Innovative technologies have dispersed limitations related to this matter. The existing gaps and trends in this area should be investigated to provide valuable visions for technical environments and researchers. Thus, 67 articles are obtained in the second layer of our taxonomy and are classified into six categories. In the first category, 25.37% (n = 17/67) of the articles focus on architecture design. In the second category, 17.91% (n = 12/67) includes security analysis articles that investigate the research status in the security area of IoT-based smart home applications. In the third category, 10.44% (n = 7/67) includes articles about security schemes. In the fourth category, 17.91% (n = 12/67) comprises security examination. In the fifth category, 13.43% (n = 9/67) analyses security protocols. In the final category, 14.92% (n = 10/67) analyses the security framework. Then, the identified basic characteristics of this emerging field are presented and provided in the following aspects. Open challenges experienced on the development of IoT-based smart home security are addressed to be adopted fully in telemedicine applications. Then, the requirements are provided to increase researcher's interest in this study area. On this basis, a number of recommendations for different parties are described to provide insights on the next steps that should be considered to enhance the security of smart homes based on IoT. A map matching for both taxonomies is developed in this study to determine the novel risks and benefits of IoT-based smart home security for real-time remote health monitoring within client and server sides in telemedicine applications.
  8. Report: Cytotoxic activity of phytochemicals from the stem bark of Calophyllum castaneum
    Lim CK, Gan SY, Yi V, Jong M, Leong CO, Mai CW, et al.
    Pak J Pharm Sci, 2019 Sep;32(5):2183-2187.
    PMID: 31813886
    Phytochemical investigation on the dichloromethane stem bark extract of Calophyllum castaneum resulted in the isolation of five compounds, namely isoblancoic acid (1), blancoic acid (2), euxanthone (3), friedelin (4) and friedelinol (5). All these compounds were isolated for the first time from this plant. Their chemical structures were elucidated based on the spectroscopic analyses. The cytotoxicity of compounds 1-5 was assessed on a panel of cancer cell lines including bone (Saos-2, mg63), colorectal (HT29, Caco-2, HCC2998, SW48, HCT116, KM12), liver (HepG2), lung (H1299, Calu-3), and brain (C6), using 5-fluorouracil as positive control. Pronounced antiproliferative activities were observed for compound 1 which exhibited a comparable activity with the positive control, against brain (C6) and colorectal (SW48, KM12, HCT116) cancer cell lines showing IC50 values in the range of 14 to 65μM. Meanwhile, compound 5 displayed a greater cytotoxic effect showing at least 2-fold more strongly than the positive control, against C6 brain cancer cells. The assay findings have unveiled the therapeutic value of phytochemicals from Calophyllum castaneum as anti-cancer agents.
  9. Fulltext Predicting Arsenic (As) Exposure on Human Health for Better Management of Drinking Water Sources
    Ahmed MF, Lim CK, Mokhtar MB, Khirotdin RPK
    Int J Environ Res Public Health, 2021 07 28;18(15).
    PMID: 34360286 DOI: 10.3390/ijerph18157997
    Chemical pollution in the transboundary Langat River in Malaysia is common both from point and non-point sources. Therefore, the water treatment plants (WTPS) at the Langat River Basin have experienced frequent shutdown incidents. However, the Langat River is one of the main sources of drinking water to almost one-third of the population in Selangor state. Meanwhile, several studies have reported a high concentration of Arsenic (As) in the Langat River that is toxic if ingested via drinking water. However, this is a pioneer study that predicts the As concentration in the Langat River based on time-series data from 2005-2014 to estimate the health risk associated with As ingestion via drinking water at the Langat River Basin. Several time-series prediction models were tested and Gradient Boosted Tree (GBT) gained the best result. This GBT model also fits better to predict the As concentration until December 2024. The mean concentration of As in the Langat River for both 2014 and 2024, as well as the carcinogenic and non-carcinogenic health risks of As ingestion via drinking water, were within the drinking water quality standards proposed by the World Health Organization and Ministry of Health Malaysia. However, the ingestion of trace amounts of As over a long period might be detrimental to human health because of its non-biodegradable characteristics. Therefore, it is important to manage the drinking water sources to minimise As exposure risks to human health.
  10. Postprandial increases in nitrogenous excretion and urea synthesis in the giant mudskipper Periophthalmodon schlosseri
    Ip YK, Lim CK, Lee SL, Wong WP, Chew SF
    J Exp Biol, 2004 Aug;207(Pt 17):3015-23.
    PMID: 15277556
    The objective of this study was to determine the effects of feeding on the excretory nitrogen (N) metabolism of the giant mudskipper, Periophthalmodon schlosseri, with special emphasis on the role of urea synthesis in ammonia detoxification. The ammonia and urea excretion rates of P. schlosseri increased 1.70- and 1.92-fold, respectively, within the first 3 h after feeding on guppies. Simultaneously, there were significant decreases in ammonia levels in the plasma and the brain, and in urea contents in the muscle and liver, of P. schlosseri at 3 h post-feeding. Thus, it can be concluded that P. schlosseri was capable of unloading ammonia originally present in some of its tissues in anticipation of ammonia released from the catabolism of excess amino acids after feeding. Subsequently, there were significant increases in urea content in the muscle, liver and plasma (1.39-, 2.17- and 1.62-fold, respectively) at 6 h post-feeding, and the rate of urea synthesis apparently increased 5.8-fold between 3 h and 6 h. Increased urea synthesis might have occurred in the liver of P. schlosseri because the greatest increase in urea content was observed therein. The excess urea accumulated in the body at 6 h was completely excreted between 6 and 12 h, and the percentage of waste-N excreted as urea-N increased significantly to 26% during this period, but never exceeded 50%, the criterion for ureotely, meaning that P. schlosseri remained ammonotelic after feeding. By 24 h, 62.7% of the N ingested by P. schlosseri was excreted, out of which 22.6% was excreted as urea-N. This is the first report on the involvement of increased urea synthesis and excretion in defense against ammonia toxicity in the giant mudskipper, and our results suggest that an ample supply of energy resources, e.g. after feeding, is a prerequisite for the induction of urea synthesis. Together, increases in nitrogenous excretion and urea synthesis after feeding effectively prevented a postprandial surge of ammonia in the plasma of P. schlosseri as reported previously for other fish species. Consequently, contrary to previous reports, there were significant decreases in the ammonia content of the brain of P. schlosseri throughout the 24 h period post-feeding, accompanied by a significant decrease in brain glutamine content between 12 h and 24 h.
  11. Polypharmacy and potentially inappropriate medications among hospitalized older adults with COVID-19 in Malaysian tertiary hospitals
    Chang CT, Mohd Shariff SM, Abu Bakar NS, Ramzuzzaman NS, Lim CK, Lim EYJ, et al.
    J Pharm Policy Pract, 2023 Jan 12;16(1):2.
    PMID: 36635766 DOI: 10.1186/s40545-022-00504-1
    INTRODUCTION: Older adults are among the most vulnerable groups during the COVID-19 epidemic, contributing to a large proportion of COVID-19-related death. Medication review and reconciliation by pharmacist can help reduce the number of potentially inappropriate medications but these services were halted during COVID-19.

    AIM: To assess the prevalence and factors associated with inappropriate medicine use among older populations with COVID-19.

    METHODS: This was a cross-sectional, retrospective analysis of medications among hospitalized older adults with COVID-19. Potentially inappropriate medication use was categorized using the Beer's and STOPP criteria.

    RESULTS: Combining both criteria, 181 (32.7%) of the 553 patients were identified to have used at least one or more potentially inappropriate medication. A marginally higher number of inappropriate medications was documented using the Beers 2019 criteria (151 PIM in 124 patients) compared to STOPP criteria (133 PIMS in 104 patients). The long-term use of proton pump inhibitors (n = 68; 12.3%) and drugs which increases the risk of postural hypotension were the most commonly reported PIM (n = 41; 7.4%). Potentially inappropriate medication use was associated with previous history of hospital admission in the past 12 months (Odds ratio [OR]: 2.27; 95% CI 1.29-3.99) and higher number of discharge medications.

    CONCLUSIONS: Nearly, one in three older adults with COVID-19 had been prescribed a PIM, and the proportion of older adults with polypharmacy increased after discharge. This highlights the importance of having clinical pharmacist conducting medication reviews to identify PIMs and ensure medication appropriateness.

  12. Physical properties and biocompatibility of oligochitosan membrane film as wound dressing
    Ujang Z, Abdul Rashid AH, Suboh SK, Halim AS, Lim CK
    J Appl Biomater Funct Mater, 2014 Dec 30;12(3):155-62.
    PMID: 24700269 DOI: 10.5301/jabfm.5000190
    BACKGROUND: The physical and biological characteristics of oligochitosan (O-C) film, including its barrier and mechanical properties, in vitro cytotoxicity and in vivo biocompatibility, were studied to assess its potential use as a wound dressing.

    METHODS: Membrane films were prepared from water-soluble O-C solution blended with various concentrations of glycerol to modify the physical properties of the films. In vitro and in vivo biocompatibility evaluations were performed using primary human skin fibroblast cultures and subcutaneous implantation in a rat model, respectively.

    RESULTS: Addition of glycerol significantly influenced the barrier and mechanical properties of the films. Water absorption capacity was in the range of 80%-160%, whereas water vapor transmission rate varied from 1,180 to 1,618 g/m2 per day. Both properties increased with increasing glycerol concentration. Tensile strength decreased while elongation at break increased with the addition of glycerol. O-C films were found to be noncytotoxic to human fibroblast cultures and histological examination proved that films are biocompatible.

    CONCLUSION: These results indicate that the membrane film from O-C has potential application as a wound-dressing material.

  13. Molecular characterization of glycation-associated skin ageing: an alternative skin model to study in vitro antiglycation activity of topical cosmeceutical and pharmaceutical formulations
    Lee KH, Ng YP, Cheah PS, Lim CK, Toh MS
    Br J Dermatol, 2017 Jan;176(1):159-167.
    PMID: 27363533 DOI: 10.1111/bjd.14832
    BACKGROUND: Glycation is a nonenzymatic reaction that cross-links a sugar molecule and protein macromolecule to form advanced glycation products (AGEs) that are associated with various age-related disorders; thus glycation plays an important role in skin chronological ageing.

    OBJECTIVES: To develop a novel in vitro skin glycation model as a screening tool for topical formulations with antiglycation properties and to further characterize, at the molecular level, the glycation stress-driven skin ageing mechanism.

    METHODS: The glycation model was developed using human reconstituted full-thickness skin; the presence of N(ε) -(carboxymethyl) lysine (CML) was used as evidence of the degree of glycation. Topical application of emulsion containing a well-known antiglycation compound (aminoguanidine) was used to verify the sensitivity and robustness of the model. Cytokine immunoassay, quantitative real-time polymerase chain reaction and histological analysis were further implemented to characterize the molecular mechanisms of skin ageing in the skin glycation model.

    RESULTS: Transcriptomic and cytokine profiling analyses in the skin glycation model demonstrated multiple biological changes, including extracellular matrix catabolism, skin barrier function impairment, oxidative stress and subsequently the inflammatory response. Darkness and yellowness of skin tone observed in the in vitro skin glycation model correlated well with the degree of glycation stress.

    CONCLUSIONS: The newly developed skin glycation model in this study has provided a new technological dimension in screening antiglycation properties of topical pharmaceutical or cosmeceutical formulations. This study concomitantly provides insights into skin ageing mechanisms driven by glycation stress, which could be useful in formulating skin antiageing therapy in future studies.

  14. Fulltext Metabolic Profile of Scytalidium parasiticum-Ganoderma boninense Co-Cultures Revealed the Alkaloids, Flavonoids and Fatty Acids that Contribute to Anti-Ganoderma Activity
    Ahmad R, Lim CK, Marzuki NF, Goh YK, Azizan KA, Goh YK, et al.
    Molecules, 2020 Dec 16;25(24).
    PMID: 33339375 DOI: 10.3390/molecules25245965
    In solving the issue of basal stem rot diseases caused by Ganoderma, an investigation of Scytalidium parasiticum as a biological control agent that suppresses Ganoderma infection has gained our interest, as it is more environmentally friendly. Recently, the fungal co-cultivation has emerged as a promising method to discover novel antimicrobial metabolites. In this study, an established technique of co-culturing Scytalidium parasiticum and Ganoderma boninense was applied to produce and induce metabolites that have antifungal activity against G. boninense. The crude extract from the co-culture media was applied to a High Performance Liquid Chromatography (HPLC) preparative column to isolate the bioactive compounds, which were tested against G. boninense. The fractions that showed inhibition against G. boninense were sent for a Liquid Chromatography-Time of Flight-Mass Spectrometry (LC-TOF-MS) analysis to further identify the compounds that were responsible for the microbicidal activity. Interestingly, we found that eudistomin I, naringenin 7-O-beta-D-glucoside and penipanoid A, which were present in different abundances in all the active fractions, except in the control, could be the antimicrobial metabolites. In addition, the abundance of fatty acids, such as oleic acid and stearamide in the active fraction, also enhanced the antimicrobial activity. This comprehensive metabolomics study could be used as the basis for isolating biocontrol compounds to be applied in oil palm fields to combat a Ganoderma infection.
  15. Fulltext Limitations of Existing Dialysis Diet Apps in Promoting User Engagement and Patient Self-Management: Quantitative Content Analysis Study
    Lim JH, Lim CK, Ibrahim I, Syahrul J, Mohamed Zabil MH, Zakaria NF, et al.
    JMIR Mhealth Uhealth, 2020 06 01;8(6):e13808.
    PMID: 32478665 DOI: 10.2196/13808
    BACKGROUND: With the unprecedented growth of mobile technology, a plethora of dialysis diet apps have been developed to promote patient dietary self-management. Nevertheless, the utility of such apps remains questionable.

    OBJECTIVE: This study aimed to evaluate the content, features, and quality of commercial dialysis diet apps for adult dialysis patients.

    METHODS: This study consisted of a quantitative content analysis of commercial dialysis diet apps downloaded from Google Play and the Apple App Store available in the Asian marketplace, searched for using the following keywords in English: dialysis diet and diet for kidney disease. Free and paid apps available in English that provide nutrition information for adult dialysis patients were included. Apps that were not relevant to the dialysis diet, not meant for patient self-management, or redundant were excluded. Apps were evaluated for language medium (subscore=1), credibility (subscore=1), food database (subscore=1), valuable features (subscore=12), health-behavior theory constructs (subscore=60), and technical quality (subscore=25). The relationships among the variables of interest were determined by Pearson correlation. Stepwise multiple linear regression analysis was performed to identify the features that contribute to greater technical quality of dialysis diet apps. Statistical significance was defined as P

  16. Keloid pathogenesis via Drosophila similar to mothers against decapentaplegic (SMAD) signaling in a primary epithelial-mesenchymal in vitro model treated with biomedical-grade chitosan porous skin regenerating template
    Lim CK, Halim AS, Yaacob NS, Zainol I, Noorsal K
    J Biosci Bioeng, 2013 Apr;115(4):453-8.
    PMID: 23177217 DOI: 10.1016/j.jbiosc.2012.10.010
    The effects of locally produced chitosan (CPSRT-NC-bicarbonate) in the intervention of keloid pathogenesis were investigated in vitro. A human keratinocyte-fibroblast co-culture model was established to investigate the protein levels of human collagen type-I, III and V in a western blotting analysis, the secreted transforming growth factor-β1 (TGF-β1) in an enzyme-linked immunosorbent assay (ELISA) and the mRNA levels of TGF-β1's intracellular signaling molecules (SMAD2, 3, 4 and 7) in a real-time PCR analysis. Keratinocyte-fibroblast co-cultures were maintained in DKSFM:DMEM:F12 (2:2:1) medium. Collagen type-I was found to be the dominant form in primary normal human dermal fibroblast (pNHDF) co-cultures, whereas collagen type-III was more abundant in primary keloid-derived human dermal fibroblast (pKHDF) co-cultures. Collagen type-V was present as a minor component in the skin. TGF-β1, SMAD2 and SMAD4 were expressed more in the pKHDF than the pNHDF co-cultures. Co-cultures with normal keratinocytes suppressed collagen type-III, SMAD2, SMAD4 and TGF-β1 expressions and CPSRT-NC-bicarbonate enhanced this effect. In conclusion, the CPSRT-NC-bicarbonate in association with normal-derived keratinocytes demonstrated an ability to reduce TGF-β1, SMAD2 and SMAD4 expressions in keloid-derived fibroblast cultures, which may be useful in keloid intervention.
  17. Fulltext Isolation and enhancement of a homogenous in vitro human Hertwig's epithelial root sheath cell population
    Farea M, Halim AS, Abdullah NA, Lim CK, Mokhtar KI, Berahim Z, et al.
    Int J Mol Sci, 2013;14(6):11157-70.
    PMID: 23712356 DOI: 10.3390/ijms140611157
    Hertwig's epithelial root sheath (HERS) cells play a pivotal role during root formation of the tooth and are able to form cementum-like tissue. The aim of the present study was to establish a HERS cell line for molecular and biochemical studies using a selective digestion method. Selective digestion was performed by the application of trypsin-EDTA for 2 min, which led to the detachment of fibroblast-like-cells, with the rounded cells attached to the culture plate. The HERS cells displayed a typical cuboidal/squamous-shaped appearance. Characterization of the HERS cells using immunofluorescence staining and flow cytometry analysis showed that these cells expressed pan-cytokeratin, E-cadherin, and p63 as epithelial markers. Moreover, RT-PCR confirmed that these cells expressed epithelial-related genes, such as cytokeratin 14, E-cadherin, and ΔNp63. Additionally, HERS cells showed low expression of CD44 and CD105 with absence of CD34 and amelogenin expressions. In conclusion, HERS cells have been successfully isolated using a selective digestion method, thus enabling future studies on the roles of these cells in the formation of cementum-like tissue in vitro.
  18. Inophyllin A, a new pyranoxanthone from Calophyllum inophyllum (Guttiferae)
    Ee GC, Kua AS, Lim CK, Jong V, Lee HL
    Nat Prod Res, 2006 May 10;20(5):485-91.
    PMID: 16644547
    In the authors' continuing search for new natural products, their recent studies on the roots of Calophyllum inophyllum (Guttiferae) have yielded a new prenylated pyranoxanthone, Inophyllin A together with the common triterpenes friedelin and stigmasterol. Structural elucidations of these compounds were achieved through (1)H, (13)C, DEPT, COSY, HSQC and HMBC experiments. The molecular mass was determined using MS techniques. The authors report here the isolation of and structural elucidation for Inophyllin A as well as its toxicity test result. The discovery of this new natural product from the unexploited Malaysian forest will certainly contribute to the search for potential natural larvicides.
  19. In vitro cytotoxicology model of oligo-chitosan and n, o-carboxymethyl chitosan using primary normal human epidermal keratinocyte cultures
    Lim CK, Halim AS, Lau HY, Ujang Z, Hazri A
    J Appl Biomater Biomech, 2007 May-Aug;5(2):82-7.
    PMID: 20799177
    Chitosan (beta-1, 4-D-glucosamine) is a deacetylated form of chitin with excellent biological properties in wound management. The natural properties of chitosan have the physical and chemical limitations to be widely used in biomedical fields. The improvement of the physical and chemical properties of chitosan with some additional chemicals will alter its biocompatibility. Therefore, the biological attribute of the modified chitosan must be evaluated. In this study, the cytotoxicity of oligo-chitosan (OC) and N, O- carboxymethyl-chitosan (NO-CMC) derivatives (O-C 1%, O-C 5%, NO-CMC 1% and NO-CMC 5%) was evaluated using primary normal human epidermal keratinocyte (pNHEK) cultures as an in vitro toxicology model at standardized cell passages (fourth passages). 3-[4, 5-dimethyl-2-thiazolyl]-2, 5-diphenyl tetrazolium bromide (MTT) was used as a cell viability assay. The O-C 1% is one of the most compatible chitosan derivatives because it steadily sustained >70% of viable cells until 72 hr post-treatment. This was followed by O-C 5%, NO-CMC 5% and NO-CMC 1%. Therefore, oligo-chitosan had the ideal properties of a biocompatible material compared to N, O- carboxymethyl-chitosan in this study.
  20. Fulltext In vitro characterization of a chitosan skin regenerating template as a scaffold for cells cultivation
    Hilmi AB, Halim AS, Hassan A, Lim CK, Noorsal K, Zainol I
    Springerplus, 2013 Dec;2(1):79.
    PMID: 23503998 DOI: 10.1186/2193-1801-2-79
    Chitosan is a marine-derived product that has been widely used in clinical applications, especially in skin reconstruction. The mammalian scaffolds derived from bovine and porcine material have many limitations, for example, prion transmission and religious concerns. Therefore, we created a chitosan skin regenerating template (SRT) and investigated the behavior of fibroblast cell-scaffold constructs. Primary human dermal fibroblasts (HDF) were isolated and then characterized using vimentin and versican. HDF were seeded into chitosan SRT at a density of 3×10(6) cells/cm(2) for fourteen days. Histological analysis and live cells imaging revealed that the cell-chitosan constructs within interconnected porous chitosan showed significant interaction between the cells as well as between the cells and the chitosan. Scanning electron microscopy (SEM) analysis revealed cells spreading and covering the pores. As the pore sizes of the chitosan SRT range between 40-140 μm, an average porosity is about 93 ± 12.57% and water uptake ratio of chitosan SRT is 536.02 ± 14.29%, it is a supportive template for fibroblast attachment and has potential in applications as a dermal substitute.
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