Displaying publications 1 - 20 of 45 in total

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  1. Fulltext Recent advances in Toxoplasma gondii immunotherapeutics
    Lim SS, Othman RY
    Korean J Parasitol, 2014 Dec;52(6):581-93.
    PMID: 25548409 DOI: 10.3347/kjp.2014.52.6.581
    Toxoplasmosis is an opportunistic infection caused by the protozoan parasite Toxoplasma gondii. T. gondii is widespread globally and causes severe diseases in individuals with impaired immune defences as well as congenitally infected infants. The high prevalence rate in some parts of the world such as South America and Africa, coupled with the current drug treatments that trigger hypersensitivity reactions, makes the development of immunotherapeutics intervention a highly important research priority. Immunotherapeutics strategies could either be a vaccine which would confer a pre-emptive immunity to infection, or passive immunization in cases of disease recrudescence or recurrent clinical diseases. As the severity of clinical manifestations is often greater in developing nations, the development of well-tolerated and safe immunotherapeutics becomes not only a scientific pursuit, but a humanitarian enterprise. In the last few years, much progress has been made in vaccine research with new antigens, novel adjuvants, and innovative vaccine delivery such as nanoparticles and antigen encapsulations. A literature search over the past 5 years showed that most experimental studies were focused on DNA vaccination at 52%, followed by protein vaccination which formed 36% of the studies, live attenuated vaccinations at 9%, and heterologous vaccination at 3%; while there were few on passive immunization. Recent progress in studies on vaccination, passive immunization, as well as insights gained from these immunotherapeutics is highlighted in this review.
  2. Comparing topical hydrocortisone cream with Hai's Perianal Support in managing symptomatic hemorrhoids in pregnancy: a preliminary trial
    Lim SS, Yu CW, Aw LD
    J Obstet Gynaecol Res, 2015 Feb;41(2):238-47.
    PMID: 25256125 DOI: 10.1111/jog.12523
    The prevalence of hemorrhoids among pregnant women is high in late pregnancy. This study was to evaluate the efficacy between drug treatment with Procort (topical hydrocortisone cream 1%) and mechanical treatment with a Hai's Perianal Support (HPS) toilet seat device in managing symptomatic hemorrhoids during the third trimester of pregnancy.
  3. Goserelin versus leuprolide before hysterectomy for uterine fibroids
    Lim SS, Sockalingam JK, Tan PC
    Int J Gynaecol Obstet, 2008 May;101(2):178-83.
    PMID: 18164303 DOI: 10.1016/j.ijgo.2007.10.020
    To compare goserelin and leuprolide given before hysterectomy for symptomatic large fibroid uteri.
  4. Large falcine meningioma presented as treatment-resistant depression: A case report
    Sim SK, Khairul Aizad A, Lim SS, Wong A
    Med J Malaysia, 2019 02;74(1):87-89.
    PMID: 30846670
    Large intracranial tumour may present only with psychiatric symptoms without any neurological deficits. Delay in surgical treatment may significantly affect the quality of life in these patients. We report a case of a young engineering student who was diagnosed as treatment-resistant depression without initial neuroimaging study. Further neuroimaging studies revealed he has a large falcine meningioma. His psychiatric symptoms resolved following surgical resection of the tumour. We emphasized the importance of initial neuroimaging study in young patients presenting with psychiatric symptoms.
  5. In vitro evaluation of osteoblast adhesion, proliferation and differentiation on chitosan-TiO2nanotubes scaffolds with Ca2+ions
    Lim SS, Chai CY, Loh HS
    Mater Sci Eng C Mater Biol Appl, 2017 Jul 01;76:144-152.
    PMID: 28482510 DOI: 10.1016/j.msec.2017.03.075
    Hydrothermally synthesized TiO2nanotubes (TNTs) were first used as a filler for chitosan scaffold for reinforcement purpose. Chitosan-TNTs (CTNTs) scaffolds prepared via direct blending and freeze drying retained cylindrical structure and showed enhanced compressive modulus and reduced degradation rate compared to chitosan membrane which experienced severe shrinkage after rehydration with ethanol. Macroporous interconnectivity with pore size of 70-230μm and porosity of 88% were found in CTNTs scaffolds. Subsequently, the functionalization of CTNTs scaffolds with CaCl2solutions (0.5mM-40.5mM) was conducted at physiological pH. The adsorption isotherm of Ca2+ions onto CTNTs scaffolds fitted well with Freundlich isotherm. CTNTs scaffolds with Ca2+ions showed high biocompatibility by promoting adhesion, proliferation and early differentiation of MG63 in a non-dose dependent manner. CTNTs scaffolds with Ca2+ions can be an alternative for bone regeneration.
  6. Fulltext VIPoma syndrome: challenges in management
    Adam N, Lim SS, Ananda V, Chan SP
    Singapore Med J, 2010 Jul;51(7):e129-32.
    PMID: 20730389
    Vasoactive intestinal peptide-producing tumour (VIPoma) or Verner-Morrison syndrome is a very rare neuroendocrine tumour. It occurs in less than ten percent of all pancreatic islet cell tumours, and about 70 percent to 80 percent of these tumours originate from the pancreas. Diagnosis is characteristically delayed. The first-line treatment is surgical. It may be curative in forty percent of patients with benign and non-metastatic disease. Palliative surgery is indicated in extensive disease, followed by conventional somatostatin analogue (octreotide) therapy. Somatostatin analogues improve hormone-mediated symptoms, reduce tumour bulk and prevent local and systemic effects. We present a female patient with VIPoma syndrome, which had metastasised to the liver at diagnosis. The patient underwent palliative Whipple procedure and subsequent cytoreductive radiofrequency ablations to her liver metastases. Unfortunately, after symptomatic improvement for three years, her disease progressed. Currently, she is on daily octreotide, achieving partial control of her symptoms.
  7. Prevalence and sociodemographic factors of malnutrition among children in Malaysia
    Khambalia AZ, Lim SS, Gill T, Bulgiba AM
    Food Nutr Bull, 2012 Mar;33(1):31-42.
    PMID: 22624296
    For many developing countries undergoing rapid economic growth and urbanization, trends in nutritional status indicate a decrease in malnutrition with an associated rise in the prevalence of obesity. An understanding of the situation among children in Malaysia is lacking.
  8. Fulltext Fabrication and characterization of graphene hydrogel via hydrothermal approach as a scaffold for preliminary study of cell growth
    Lim HN, Huang NM, Lim SS, Harrison I, Chia CH
    Int J Nanomedicine, 2011;6:1817-23.
    PMID: 21931479 DOI: 10.2147/IJN.S23392
    Three-dimensional assembly of graphene hydrogel is rapidly attracting the interest of researchers because of its wide range of applications in energy storage, electronics, electrochemistry, and waste water treatment. Information on the use of graphene hydrogel for biological purposes is lacking, so we conducted a preliminary study to determine the suitability of graphene hydrogel as a substrate for cell growth, which could potentially be used as building blocks for biomolecules and tissue engineering applications.
  9. Oral celecoxib versus oral diclofenac for post-perineal repair analgesia after spontaneous vaginal birth: a randomised trial
    Lim SS, Tan PC, Sockalingam JK, Omar SZ
    Aust N Z J Obstet Gynaecol, 2008 Feb;48(1):71-7.
    PMID: 18275575 DOI: 10.1111/j.1479-828X.2007.00808.x
    To compare oral celecoxib with oral diclofenac as pain reliever after perineal repair following normal vaginal birth.
  10. A dot enzyme immunoassay for dengue 3 virus: comparison with the haemagglutination inhibition test
    Cardosa MJ, Noor Sham S, Tio PH, Lim SS
    Southeast Asian J. Trop. Med. Public Health, 1988 Dec;19(4):591-4.
    PMID: 3238470
    A dot enzyme immunoassay (DEIA) was used to determine the levels of antibody to dengue 3 virus in the acute and convalescent sera of febrile patients with a clinical diagnosis of dengue fever or dengue haemorrhagic fever. The antibody titres were compared with titres determined by the haemagglutination inhibition (HI) test. The results of the study showed that, besides being more simple to perform, the DEIA is in order of magnitude more sensitive than the HI test. Furthermore, the data suggest that it is possible to use a single dilution as a cutoff point to predict with reasonable accuracy, if a patient has had a recent dengue infection. The DEIA test for antibodies to dengue virus is an appropriate technology highly suitable for rapid diagnosis and surveillance in developing countries.
  11. Pushing microbial desalination cells towards field application: Prevailing challenges, potential mitigation strategies, and future prospects
    Salehmin MNI, Lim SS, Satar I, Daud WRW
    Sci Total Environ, 2021 Mar 10;759:143485.
    PMID: 33279184 DOI: 10.1016/j.scitotenv.2020.143485
    Microbial desalination cells (MDCs) have been experimentally proven as a versatile bioelectrochemical system (BES). They have the potential to alleviate environmental pollution, reduce water scarcity and save energy and operational costs. However, MDCs alone are inadequate to realise a complete wastewater and desalination treatment at a high-efficiency performance. The assembly of identical MDC units that hydraulically and electrically connected can improve the performance better than standalone MDCs. In the same manner, the coupling of MDCs with other BES or conventional water reclamation technology has also exhibits a promising performance. However, the scaling-up effort has been slowly progressing, leading to a lack of knowledge for guiding MDC technology into practicality. Many challenges remain unsolved and should be mitigated before MDCs can be fully implemented in real applications. Here, we aim to provide a comprehensive chronological-based review that covers technological limitations and mitigation strategies, which have been developed for standalone MDCs. We extend our discussion on how assembled, coupled and scaled-up MDCs have improved in comparison with standalone and lab-scale MDC systems. This review also outlines the prevailing challenges and potential mitigation strategies for scaling-up based on large-scale specifications and evaluates the prospects of selected MDC systems to be integrated with conventional anaerobic digestion (AD) and reverse osmosis (RO). This review offers several recommendations to promote up-scaling studies guided by the pilot scale BES and existing water reclamation technologies.
  12. Curcumin and a hemi-analogue with improved blood-brain barrier permeability protect against amyloid-beta toxicity in Caenorhabditis elegans via SKN-1/Nrf activation
    Lee EH, Lim SS, Yuen KH, Lee CY
    J Pharm Pharmacol, 2019 May;71(5):860-868.
    PMID: 30515807 DOI: 10.1111/jphp.13052
    OBJECTIVES: This study aims to investigate the blood-brain barrier (BBB) permeability of curcumin analogues with shortened linkers and their ability to protect against amyloid-beta toxicity in a whole organism model.

    METHOD: Four curcumin analogues were synthesized. These analogues and curcumin were evaluated for their BBB permeability in the parallel artificial membrane permeability assay. The transgenic Caenorhabditis elegansGMC101 that expresses human Aβ1-42 was treated with the compounds to evaluate their ability to delay Aβ-induced paralysis. Expression of skn-1mRNA was examined on nematodes treated with selected efficacious compounds. In vitro Aβ aggregation in the presence of the compounds was performed.

    KEY FINDINGS: The four analogues showed improved BBB permeability vs curcumin in the PAMPA with the hemi-analogue C4 having the highest permeability coefficient. At 100 μm, analogues C1 and C4 as well as curcumin significantly prolonged the survival of the nematodes protecting against Aβ toxicity. However, only curcumin and C4 showed protection at lower concentrations. skn-1mRNA was significantly elevated in nematodes treated with curcumin and C4 indicating SKN-1/Nrf activation as a possible mode of action.

    CONCLUSIONS: Analogue C4 provides a new lead for the development of a curcumin-based compound for protection against Aβ toxicity with an improved BBB permeability.

  13. Fulltext Ultrasonic liquid exfoliation for producing graphene materials from rice stem: Investigating cellular components and functionalities
    Wu X, Sivakumar M, Lim SS, Wu T, Heng PC
    Ultrason Sonochem, 2024 Feb;103:106782.
    PMID: 38309050 DOI: 10.1016/j.ultsonch.2024.106782
    This study investigates a prospective and straightforward method for producing graphene material derived from biomass, examining the influence of plant cell composition and functions. The experimental outcomes highlight ultrasound's crucial role in synthesizing graphene material sourced from biomass. Ultrasound, a pivotal element in the experiment, significantly affects graphene production from biomass by working synergistically with the liquid components in the solvent system. Notably, the ethanol content reduces the solution's surface tension, facilitating the effective dispersion of biochar and graphene oxide sheets throughout the process. Simultaneously, the water content maintains the solution's polarity, enhancing the cavitation effect induced by ultrasound. Biomass-derived graphene is exfoliated utilizing an ultrasonic bath system (134.4 W, 40 kHz, 0.5 W/cm2) from biochar. The as-synthesized graphene oxide exhibits a structure comprising a few layers while remaining intact, featuring abundant functional groups. Interestingly, the resulting product displays nanopores with an approximate diameter of 100 nm. These nanopores are attributed to preserving specific cell structures, particularly those with specialized cell wall structures or secondary metabolite deposits from biomass resources. The study's findings shed light on the impact of cellular structure on synthesizing graphene material sourced from biomass, emphasizing the potential application of ultrasound as a promising approach in graphene production.
  14. Insights into the equilibrium, kinetic and thermodynamics of nickel removal by environmental friendly Lansium domesticum peel biosorbent
    Lam YF, Lee LY, Chua SJ, Lim SS, Gan S
    Ecotoxicol Environ Saf, 2016 May;127:61-70.
    PMID: 26802563 DOI: 10.1016/j.ecoenv.2016.01.003
    Lansium domesticum peel (LDP), a waste material generated from the fruit consumption, was evaluated as a biosorbent for nickel removal from aqueous media. The effects of dosage, contact time, initial pH, initial concentration and temperature on the biosorption process were investigated in batch experiments. Equilibrium data were fitted by the Langmuir, Freundlich, Temkin and Dubinin-Radushkevich models using nonlinear regression method with the best-fit model evaluated based on coefficient of determination (R(2)) and Chi-square (χ(2)). The best-fit isotherm was found to be the Langmuir model exhibiting R(2) very close to unity (0.997-0.999), smallest χ(2) (0.0138-0.0562) and largest biosorption capacity (10.1mg/g) at 30°C. Kinetic studies showed that the initial nickel removal was rapid with the equilibrium state established within 30min. Pseudo-second-order model was the best-fit kinetic model indicating the chemisorption nature of the biosorption process. Further data analysis by the intraparticle diffusion model revealed the involvement of several rate-controlling steps such as boundary layer and intraparticle diffusion. Thermodynamically, the process was exothermic, spontaneous and feasible. Regeneration studies indicated that LDP biosorbent could be regenerated using hydrochloric acid solution with up to 85% efficiency. The present investigation proved that LDP having no economic value can be used as an alternative eco-friendly biosorbent for remediation of nickel contaminated water.
  15. The biocathode of microbial electrochemical systems and microbially-influenced corrosion
    Kim BH, Lim SS, Daud WR, Gadd GM, Chang IS
    Bioresour Technol, 2015 Aug;190:395-401.
    PMID: 25976915 DOI: 10.1016/j.biortech.2015.04.084
    The cathode reaction is one of the most important limiting factors in bioelectrochemical systems even with precious metal catalysts. Since aerobic bacteria have a much higher affinity for oxygen than any known abiotic cathode catalysts, the performance of a microbial fuel cell can be improved through the use of electrochemically-active oxygen-reducing bacteria acting as the cathode catalyst. These consume electrons available from the electrode to reduce the electron acceptors present, probably conserving energy for growth. Anaerobic bacteria reduce protons to hydrogen in microbial electrolysis cells (MECs). These aerobic and anaerobic bacterial activities resemble those catalyzing microbially-influenced corrosion (MIC). Sulfate-reducing bacteria and homoacetogens have been identified in MEC biocathodes. For sustainable operation, microbes in a biocathode should conserve energy during such electron-consuming reactions probably by similar mechanisms as those occurring in MIC. A novel hypothesis is proposed here which explains how energy can be conserved by microbes in MEC biocathodes.
  16. Fulltext Preliminary In Vitro Evaluation of Chitosan-Graphene Oxide Scaffolds on Osteoblastic Adhesion, Proliferation, and Early Differentiation
    Wong SHM, Lim SS, Tiong TJ, Show PL, Zaid HFM, Loh HS
    Int J Mol Sci, 2020 Jul 22;21(15).
    PMID: 32708043 DOI: 10.3390/ijms21155202
    An ideal scaffold should be biocompatible, having appropriate microstructure, excellent mechanical strength yet degrades. Chitosan exhibits most of these exceptional properties, but it is always associated with sub-optimal cytocompatibility. This study aimed to incorporate graphene oxide at wt % of 0, 2, 4, and 6 into chitosan matrix via direct blending of chitosan solution and graphene oxide, freezing, and freeze drying. Cell fixation, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide, alkaline phosphatase colorimetric assays were conducted to assess cell adhesion, proliferation, and early differentiation of MG63 on chitosan-graphene oxide scaffolds respectively. The presence of alkaline phosphatase, an early osteoblast differentiation marker, was further detected in chitosan-graphene oxide scaffolds using western blot. These results strongly supported that chitosan scaffolds loaded with graphene oxide at 2 wt % mediated cell adhesion, proliferation, and early differentiation due to the presence of oxygen-containing functional groups of graphene oxide. Therefore, chitosan scaffolds loaded with graphene oxide at 2 wt % showed the potential to be developed into functional bone scaffolds.
  17. Accelerated wound closure - Systematic evaluation of cellulose acetate effects on biologically active molecules release from amniotic fluid stem cells (AFSCs)
    Nuge T, Liu X, Tshai KY, Lim SS, Nordin N, Hoque ME, et al.
    Biotechnol Appl Biochem, 2021 Apr 07.
    PMID: 33826152 DOI: 10.1002/bab.2162
    Despite a lot of intensive research on cells-scaffolds interaction, focused are mainly on the capacity of construct scaffolds to regulate cell mobility, migration and cytotoxicity. The effect of the scaffold's topographical and material properties on the expression of biologically active compounds from stem cells is not well understood. In this study, the influence of cellulose acetate (CA) on the electrospinnability of gelatin and the roles of gelatin-cellulose acetate (Ge-CA) on modulating the release of biologically active compounds from amniotic fluid stem cells (AFSCs) is emphasized. It was found that the presence of a small amount of CA could provide a better microenvironment that mimics AFSCs' niche. However, a large amount of CA exhibited no significant effect on AFSCs migration and infiltration. Further study on the effect of surface topography and mechanical properties on AFSCs showed that the tailored microenvironment provided by the Ge-CA scaffolds had transduced physical cues to biomolecules released into the culture media. It was found that the AFSCs seeded on electrospun scaffolds with less CA proportions has profound effects on the secretion of metabolic compounds compared to those with higher CA contained and gelatin coating. The enhanced secretion of biologically active molecules by the AFSCs on the electrospun scaffolds was proven by the accelerated wound closure on the injured human dermal fibroblast (HDF) model. The rapid HDF cell migration could be anticipated due to a higher level of paracrine factors in AFSCs media. Our study demonstrates that the fibrous topography and mechanical properties of the scaffold is a key material property that modulates the high expression of biologically active compounds from the AFSCs. The discovery elucidates a new aspect of material functions and scaffolds material-AFSCs interaction for regulating biomolecules release to promote tissue regeneration/repair. To the best of our knowledge, this is the first report describing the scaffolds material-AFSCs interaction and the efficacy of scratch assays on quantifying the cell migration in response to the AFSCs metabolic products. This article is protected by copyright. All rights reserved.
  18. Algae utilization and its role in the development of green cities
    Chew KW, Khoo KS, Foo HT, Chia SR, Walvekar R, Lim SS
    Chemosphere, 2020 Dec 15;268:129322.
    PMID: 33359993 DOI: 10.1016/j.chemosphere.2020.129322
    With the rapid urbanisation happening around the world followed by the massive demand for clean energy resources, green cities play a pivotal role in building a sustainable future for the people. The continuing depletion of natural resources has led to the development of renewable energy with algae as the promising source. The high growth rate of microalgae and their strong bio-fixation ability to convert CO2 into O2 have been gaining attention globally and intensive research has been conducted regarding the microalgae benefits. The focus on potential of microalgae in contributing to the development of green cities is rising. The advantage of microalgae is their ability to gather energy from sunlight and carbon dioxide, followed by transforming the nutrients into biomass and oxygen. This leads to the creation of green cities through algae cultivation as waste and renewable materials can be put to good use. The challenges that arise when using algae and the future prospect in terms of SDGs and economy will also be covered in this review. The future of green cities can be enhanced with the adaptation of algae as the source of renewable plants to create a better outlook of an algae green city.
  19. Enhanced bio-production from CO2 by microbial electrosynthesis (MES) with continuous operational mode
    Izadi P, Fontmorin JM, Lim SS, Head IM, Yu EH
    Faraday Discuss, 2021 07 16;230(0):344-359.
    PMID: 34259692 DOI: 10.1039/d0fd00132e
    Technologies able to convert CO2 to various feedstocks for fuels and chemicals are emerging due to the urge of reducing greenhouse gas emissions and de-fossilizing chemical production. Microbial electrosynthesis (MES) has been shown a promising technique to synthesize organic products particularly acetate using microorganisms and electrons. However, the efficiency of the system is low. In this study, we demonstrated the simple yet efficient strategy in enhancing the efficiency of MES by applying continuous feeding regime. Compared to the fed-batch system, continuous operational mode provided better control of pH and constant medium refreshment, resulting in higher acetate production rate and more diverse bio-products, when the cathodic potential of -1.0 V Ag/AgCl and dissolved CO2 were provided. It was observed that hydraulic retention time (HRT) had a direct effect on the pattern of production, acetate production rate and coulombic efficiency. At HRT of 3 days, pH was around 5.2 and acetate was the dominant product with the highest production rate of 651.8 ± 214.2 ppm per day and a significant coulombic efficiency of 90%. However at the HRT of 7 days, pH was lower at around 4.5, and lower but stable acetate production rate of 280 ppm per day and a maximum coulombic efficiency of 80% was obtained. In addition, more diverse and longer chain products, such as butyrate, isovalerate and caproate, were detected with low concentrations only at the HRT of 7 days. Although microbial community analysis showed the change in the planktonic cells communities after switching the fed-batch mode to continuous feeding regime, Acetobacterium still remained as the responsible bacteria for CO2 reduction to acetate, dominating the cathodic biofilm.
  20. The conundrum of waste cooking oil: Transforming hazard into energy
    Foo WH, Chia WY, Tang DYY, Koay SSN, Lim SS, Chew KW
    J Hazard Mater, 2021 Sep 05;417:126129.
    PMID: 34229396 DOI: 10.1016/j.jhazmat.2021.126129
    Waste cooking oil (WCO) is considered as one of the hazardous wastes because improper disposal of WCO can cause significant environmental problems such as blockages of drains and sewers as well as water or soil pollution. In this review, the physical and chemical properties of WCO are evaluated along with its regulations and policies in different countries to promote WCO refined biofuels. Blended WCO can be an auxiliary fuel for municipal solid waste incinerators while the heat produced is able to form superheated steam and subsequently generate electricity via combined heat and power system. Also, WCO contains high ratio of hydrogen atoms compared to carbon and oxygen atoms, making it able to be catalytically cracked, synthesizing hydrogen gas. WCO-based biodiesel has been traditionally produced by transesterification in order to substitute petroleum-based diesel which has non-degradability as well as non-renewable features. Hence, the potentials of hazardous WCO as a green alternative energy source for electricity generation, hydrogen gas as well as biofuels production (e.g. biodiesel, biogas, biojet fuel) are critically discussed due to its attractive psychochemical properties as well as its economic feasibility. Challenges of the WCO utilization as a source of energy are also reported while highlighting its future prospects.
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