Displaying publications 21 - 40 of 41 in total

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  1. Fulltext Helminthic Infection and Nutritional Studies among Orang Asli Children in Sekolah Kebangsaan Pos Legap, Perak
    Wong WK, Foo PC, Roze MN, Pim CD, Subramaniam P, Lim BH
    Can J Infect Dis Med Microbiol, 2016;2016:1326085.
    PMID: 27366156 DOI: 10.1155/2016/1326085
    Background. Orang Asli (aborigine) children are susceptible to soil-transmitted helminth (STH) infections due to their lifestyle and substandard sanitation system. Objectives. This study aimed to examine the helminthic and nutritional status of Orang Asli school children in Sekolah Kebangsaan Pos Legap, a remote primary school at Kuala Kangsar District in the state of Perak, Malaysia. In addition, the sensitivities of four STH stool examination techniques were also compared. Methods. Demography and anthropometry data were collected by one-to-one interview session. Collected stools were examined with four microscopy techniques, namely, direct wet mount, formalin ether concentration (FEC), Kato-Katz (KK), and Parasep™. Results. Anthropometry analysis showed that 78% (26/33) of children in SK Pos Legap were malnourished and 33% (11/33) of them were stunted. Stool examinations revealed almost all children (97%) were infected by either one of the three commonest STHs. FEC was the most sensitive method in detection of the three helminth species. Conclusion. This study revealed that STH infections and nutritional status still remain a health concern among the Orang Asli children. These communal problems could be effectively controlled by regular monitoring of STH infection loads, administration of effective antihelminthic drug regimen, and also implementation of effective school nutritional programs.
  2. Development of a thermostabilised triplex LAMP assay with dry-reagent four target lateral flow dipstick for detection of Entamoeba histolytica and non-pathogenic Entamoeba spp
    Foo PC, Chan YY, Mohamed M, Wong WK, Nurul Najian AB, Lim BH
    Anal Chim Acta, 2017 May 08;966:71-80.
    PMID: 28372729 DOI: 10.1016/j.aca.2017.02.019
    This study highlighted the development of a four target nitrocellulose-based nucleic acid lateral flow immunoassay biosensor in a dry-reagent strip format for interpretation of double-labelled double-stranded amplicons from thermostabilised triplex loop-mediated isothermal amplification assay. The DNA biosensor contained two test lines which captured biotin and texas red labelled amplicons; a LAMP internal amplification control line that captured digoxigenin labelled amplicon; and a chromatography control line that validated the functionality of the conjugated gold nanoparticles and membrane. The red lines on detection pad were generated when the gold nanoparticles conjugated antibody bound to the fluorescein labelled amplicons, and the capture agents bound to their specific hapten on the other 5' end of the double-stranded amplicon. The applicability of this DNA biosensor was demonstrated using amoebiasis-causing Entamoeba histolytica simultaneously with the non-pathogenic but morphologically identical Entamoeba dispar and Entamoeba moshkovskii. The biosensor detection limit was 10 E. histolytica trophozoites, and revealed 100% specificity when it was evaluated against 3 medically important Entamoeba species and 75 other pathogenic microorganisms. Heat stability test showed that the biosensor was stable for at least 181 days at ambient temperature. This ready-to-use and cold-chain-free biosensor facilitated the post-LAMP analysis based on visualisation of lines on strip instead of observation of amplicon patterns in agarose gel.
  3. Parallel ELISAs using crude soluble antigen and excretory-secretory antigen for improved serodiagnosis of amoebic liver abscess
    Wong WK, Foo PC, Olivos-Garcia A, Noordin R, Mohamed Z, Othman N, et al.
    Acta Trop, 2017 Aug;172:208-212.
    PMID: 28506795 DOI: 10.1016/j.actatropica.2017.05.017
    Crude soluble antigen (CSA) produced from Entamoeba histolytica trophozoite is conventionally used for serodiagnosis of invasive amoebiasis. However, high background seropositivities by CSA-assay in endemic areas complicate the interpretation of positive result in clinical settings. Instead, incorporating a second assay which indicates active or recent infection into the routine amoebic serology could possibly complement the limitations of CSA-assay. Hence, the present study aimed to evaluate the diagnostic efficacies of indirect ELISAs using CSA and excretory-secretory antigen (ESA) for serodiagnosis of amoebic liver abscess (ALA). Reference standard for diagnosis of ALA at Hospital Universiti Sains Malaysia is based on clinical presentation, radiological imaging and positive indirect haemagglutination assay (titer ≥256). Five groups of human serum samples collected from the hospital included Group I - ALA diagnosed by the reference standard and pus aspirate analysis using real-time PCR (n=10), Group II - ALA diagnosed by the reference standard only (n=41), Group III - healthy control (n=45), Group IV - other diseases control (n=51) and Group V - other infectious diseases control (n=31). For serodiagnosis of ALA serum samples (Group I and II), CSA-ELISA showed sensitivities of 100% for both groups, while ESA-ELISA showed sensitivities of 100% and 88%, respectively. For serodiagnosis of non-ALA serum samples (Group III, IV and V), CSA-ELISA showed specificities of 91%, 75% and 100%, respectively; while ESA-ELISA showed specificities of 96%, 98% and 100%, respectively. Indirect ELISAs using CSA and ESA have shown distinct strength for serodiagnosis of ALA, in terms of sensitivity and specificity, respectively. In conclusion, parallel analysis by both assays improved the overall efficacies of amoebic serology as compared to either single assay.
  4. Characterization of Chlamydomonas Ribulose-1,5-bisphosphate carboxylase/oxygenase variants mutated at residues that are post-translationally modified
    Rasineni GK, Loh PC, Lim BH
    Biochim Biophys Acta Gen Subj, 2017 Feb;1861(2):79-85.
    PMID: 27816753 DOI: 10.1016/j.bbagen.2016.10.027
    BACKGROUND: Ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) is the chloroplast enzyme that fixes CO2 in photosynthesis, but the enzyme also fixes O2, which leads to the wasteful photorespiratory pathway. If we better understand the structure-function relationship of the enzyme, we might be able to engineer improvements. When the crystal structure of Chlamydomonas Rubisco was solved, four new posttranslational modifications were observed which are not present in other species. The modifications were 4-hydroxylation of the conserved Pro-104 and 151 residues, and S-methylation of the variable Cys-256 and 369 residues, which are Phe-256 and Val-369 in land plants. Because the modifications were only observed in Chlamydomonas Rubisco, they might account for the differences in kinetic properties between the algal and plant enzymes.

    METHODS: Site-directed mutagenesis and chloroplast transformation have been used to test the essentiality of these modifications by replacing each of the residues with alanine (Ala). Biochemical analyses were done to determine the specificity factors and kinetic constants.

    RESULTS: Replacing the modified-residues in Chlamydomonas Rubisco affected the enzyme's catalytic activity. Substituting hydroxy-Pro-104 and methyl-Cys-256 with alanine influenced Rubisco catalysis.

    CONCLUSION: This is the first study on these posttranslationally-modified residues in Rubisco by genetic engineering. As these forms of modifications/regulation are not available in plants, the modified residues could be a means to modulate Rubisco activity.

    GENERAL SIGNIFICANCE: With a better understanding of Rubisco structure-function, we can define targets for improving the enzyme.

  5. Fulltext Comparison and optimization of conventional and ultrasound-assisted solvent extraction for synthetization of lemongrass (Cymbopogon)-infused cooking oil
    Lim SF, Hamdan A, David Chua SN, Lim BH
    Food Sci Nutr, 2021 May;9(5):2722-2732.
    PMID: 34026085 DOI: 10.1002/fsn3.2234
    The lemongrass plant, which is widely cultivated in Asia, Australia, and Africa, has been reported to have many significant health benefits such as antimicrobial, insecticide, anticancer, fight fever, and disinfection. Therefore, it is an added benefit to have lemongrass compounds in cooking oil. This study was aimed to compare the conventional (CSE), and ultrasound-assisted solvent extraction (UASE) for citral compounds from lemongrass (Cymbopogon) leaves and to optimize the best extraction method using the response surface methodology (RSM) and ANOVA. RSM design of experiments using three types of cooking oils; palm oil, sunflower oil, and corn oil. The effect of three independent variables, which are temperature (48.2-81.8°C), extraction time (4.8-55.2 min), and solvent to leaves ratio (5.3-18.7), was investigated. The characterization of lemongrass-infused cooking oil was evaluated by Fourier transform infrared spectroscopy (FT-IR), Gas Chromatography-Mass Spectrometry (GC-MS) and Scanning Electron Microscopy (SEM) analysis for confirmation of the citral compound extraction. This extraction process is optimized using Response Surface Methodology (RSM) for producing the lemongrass-infused cooking oil. After optimization, the UASE process gives 1.009 × 106 maximum citral area for palm oil and 1.767 × 106 maximum citral area for sunflower oil. CSE process only can give 2.025 × 105 and 2.179 × 105 citral area in the GC-MS spectrum for palm oil and sunflower oil respectively. For both the UASE and the CSE, the optimum operating conditions are 81.8°C of extraction temperature and 55.2 min of extraction time except for lemongrass-infused palm oil in the CSE process with 45 min extraction time. The optimum solvent to leaves ratio varies from 5.3:1 to 12.9:1. This study found that corn oil cannot be used as a solvent to extract lemongrass-infused cooking oil due to the insignificant changes and no citral peak. The lemongrass (Cymbopogon)-infused palm oil and sunflower oil extracted using the UASE have a higher maximum citral area than the CSE process.
  6. Fulltext Evaluation of competency and job satisfaction by positive human psychology among physical education teachers at the university level: A systematic review
    Yan T, Teo EW, Lim BH, Lin B
    Front Psychol, 2022;13:1084961.
    PMID: 36605263 DOI: 10.3389/fpsyg.2022.1084961
    The study aimed to determine how a teacher's competency at the university level related to professional commitment and job satisfaction. This systematic review intends to determine physical education teachers' competency and job satisfaction. One of the main objectives of physical education programs is to increase various activities of the student, especially physical activities and participation in it. Students who participate in physical activities feel a variety of emotions, and these may enhance their mental and physical well-being. The study concerns the teachers' satisfaction in effectively influencing and teaching the students. Job satisfaction refers to teachers' feelings and positive attitudes toward their work. The five components of job satisfaction are pay, promotion, supervision, co-workers, and work itself. Job satisfaction is broken down into these five components. Work as a teacher is one of the most important components of a teacher's or teacher's success at work and one of the key criteria for the school's achievement. Electronic libraries were explored, including Google Scholar, PubMed, Embase, Bing Academic, and Cochrane. Appropriate keywords were used for searching the literature. By applying certain inclusion and exclusion criteria, the final studies were selected for evaluation. The study's findings showed that physical education instructors had high levels of teaching competence and moderate levels of job satisfaction. The findings demonstrated that job satisfaction and competency rise when degree levels rise, and relatedness, skill, and autonomy self-motivation ensue. Students' motivation for physical education was greatly influenced by the teachers' support, motivation, and mastery climate. The self-determination theory positively enhances physical education from the teacher's perspective on PE, increasing instruction effectiveness.
  7. Fulltext Comparison of Brugia-Elisa and thick blood smear examination in a prevalence study of brugian filariasis in Setiu, Terengganu, Malaysia
    Lim BH, Rahmah N, Afifi SAB, Ramli A, Mehdi R
    Med J Malaysia, 2001 Dec;56(4):491-6.
    PMID: 12014770
    A total of 1,134 finger-pricked blood samples were collected from residents of Setiu, Terengganu. A drop of blood was used to make thick blood smear and about four drops were used for obtaining serum. The smears were stained and examined by the State Vector Control Unit in Kuala Terengganu, while the serum samples were tested for specific IgG4 antibodies to a novel recombinant antigen using Brugia-Elisa. Prevalence of filariasis in these areas were found to be 0.26% (3/1,134) using thick blood smear examination and 2.47% (28/1,134) using Brugia-Elisa, thus demonstrating the greater sensitivity of the latter test. In addtion, Brugia-Elisa showed a high level of specificity (97.8%, 1,106/1,131) when compared to thick blood smear examination.
  8. Pelvic tuberculosis: an uncommon gynaecological problem in Malaysia
    Sivanesaratnam V, Lim BH, Sivanesan S, Menon A
    J Trop Med Hyg, 1986 Aug;89(4):167-9.
    PMID: 3783810
    Tuberculosis of the genital tract was diagnosed in only 12 patients during the 17 year period from March 1968 to February 1985 at the University Hospital, Kuala Lumpur, which serves as a major referral centre in Malaysia. The incidence was 0.31 per 1000 gynaecological admissions and the peak age incidence was in the age group 26 to 35 years. The surgical management was mainly conservative as infertility was the most frequent mode of presentation (50%). Evidence of previous pulmonary tuberculosis was present in only five cases. Adnexal adhesions were the commonest pelvic finding; the fallopian tubes and endometrium were affected with equal frequency. Positive cultures for Mycobacterium tuberculosis were obtained in only five of the 12 patients. All patients received combination anti-tuberculosis drugs with satisfactory response.
  9. Fulltext Thyrotoxicosis in pregnancy--a six year review
    Lim BH, Raman S, Sivanesaratnam V, Ngan A
    Singapore Med J, 1989 Dec;30(6):539-41.
    PMID: 2635396
    Twenty eight patients with hyperthyroidism complicating their pregnancies were seen at the Obstetrics and Gynaecology Department, University Hospital, Kuala Lumpur, Malaysia in a six-year period. All patients were treated with antithyroid drugs, carbimazole being the mainstay of treatment. The incidence of the disease was 0.9 per 1000 births and was similar with other series. No cases of fetal goitre were noted. The mean birth weight was 2952 g; there was no significant difference in the birth weight of term live births in patients treated with carbimazole alone or carbimazole combined with propranolol.
  10. Entamoeba histolytica antigenic protein detected in pus aspirates from patients with amoebic liver abscess
    Othman N, Mohamed Z, Yahya MM, Leow VM, Lim BH, Noordin R
    Exp Parasitol, 2013 Aug;134(4):504-10.
    PMID: 23680184 DOI: 10.1016/j.exppara.2013.05.001
    Entamoeba histolytica is a causative agent of amoebic liver abscess (ALA) and is endemic in many underdeveloped countries. We investigated antigenic E. histolytica proteins in liver abscess aspirates using proteomics approach. Pus samples were first tested by real-time PCR to confirm the presence of E. histolytica DNA and the corresponding serum samples tested for E. histolytica-specific IgG by a commercial ELISA. Proteins were extracted from three and one pool(s) of pus samples from ALA and PLA (pyogenic liver abscess) patients respectively, followed by analysis using isoelectric focussing, SDS-PAGE and Western blot. Unpurified pooled serum samples from infected hamsters and pooled human amoebic-specific IgG were used as primary antibodies. The antigenic protein band was excised from the gel, digested and analysed by MALDI-TOF/TOF and LC-MS/MS. The results using both primary antibodies showed an antigenic protein band of ∼14kDa. Based on the mass spectrum analysis, putative tyrosine kinase is the most probable identification of the antigenic band.
  11. Comparison of protein-free defined media, and effect of L-cysteine and ascorbic acid supplementation on viability of axenic Entamoeba histolytica
    Wong WK, Tan ZN, Lim BH, Mohamed Z, Olivos-Garcia A, Noordin R
    Parasitol Res, 2011 Feb;108(2):425-30.
    PMID: 20922423 DOI: 10.1007/s00436-010-2083-8
    Entamoeba histolytica is the etiologic agent for amoebiasis. The excretory-secretory (ES) products of the trophozoites contain virulence factors and antigens useful for diagnostic applications. Contaminants from serum supplements and dead trophozoites impede analysis of ES. Therefore, a protein-free medium that can sustain maximum viability of E. histolytica trophozoites for the longest time duration will enable collection of contaminant-free and higher yield of ES products. In the present study, we compared the efficacy of four types of media in maintaining ≥ 95% trophozoite viability namely Roswell Memorial Park Institute (RPMI-1640), Dulbecco's Modified Eagle Medium (DMEM), phosphate-buffered saline for amoeba (PBS-A), and Hank's balanced salt solution (HBSS). Concurrently, the effect of adding L: -cysteine and ascorbic acid (C&A) to each medium on the parasite viability was also compared. DMEM and RPMI 1640 showed higher viabilities as compared to PBS-A and HBSS. Only RPMI 1640 showed no statistical difference with the control medium for the first 4 h, however the ≥ 95% viability was only maintained for the first 2 h. The other protein-free media showed differences from the serum- and vitamin-free TYI-S-33 control media even after 1 h of incubation. When supplemented with C&A, all media were found to sustain higher trophozoite viabilities than those without the supplements. HBSS-C&A, DMEM-C&A, and RPMI 1640-C&A demonstrated no difference (P>0.05) in parasite viabilities when compared with the control medium throughout the 8-h incubation period. DMEM-C&A showed an eightfold increment in time duration of sustaining ≥ 95% parasite viability, i.e. 8 h, as compared to DMEM alone. Both RPMI 1640-C&A and HBSS-C&A revealed fourfold and threefold increments (i.e., 8 and 6 h, respectively), whereas PBS-A-C&A showed only one fold improvement (i.e., 2 h) as compared to the respective media without C&A. Thus, C&A-supplemented DMEM or RPMI are recommended for collection of ES products.
  12. Fulltext Analysis of Entamoeba histolytica excretory-secretory antigen and identification of a new potential diagnostic marker
    Wong WK, Tan ZN, Othman N, Lim BH, Mohamed Z, Olivos Garcia A, et al.
    Clin Vaccine Immunol, 2011 Nov;18(11):1913-7.
    PMID: 21918120 DOI: 10.1128/CVI.05356-11
    Serodiagnosis of amoebiasis remains the preferred method for diagnosis of amoebic liver abscess (ALA). However, the commercially available kits are problematic in areas of endemicity due to the persistently high background antibody titers. Human serum samples (n = 38) from patients with ALA who live in areas of endemicity were collected from Hospital Universiti Sains Malaysia during the period of 2008 to 2010. Western blots using excretory-secretory antigen (ESA) collected from axenically grown Entamoeba histolytica were probed with the above serum samples. Seven antigenic proteins of ESA with various reactivities were identified, i.e., 152 kDa, 131 kDa, 123 kDa, 110 kDa, 100 kDa, 82 kDa, and 76 kDa. However, only the 152-kDa and 110-kDa proteins showed sensitivities above 80% in the Western blot analysis. All the antigenic proteins showed undetectable cross-reactivity when probed with healthy human serum samples (n = 30) and serum samples from other infections (n = 33). From the matrix-assisted laser desorption ionization-two-stage time of flight (MALDI-TOF/TOF) analysis, the proteins were identified as heavy subunits of E. histolytica lectin and E. histolytica pyruvate phosphate dikinase, respectively. Use of the E. histolytica lectin for diagnosis of ALA has been well reported by researchers and is being used in commercialized kits. However, this is the first report on the potential use of pyruvate phosphate dikinase for diagnosis of ALA; thus, this molecule merits further evaluation on its diagnostic value using a larger panel of serum samples.
  13. Fulltext Effects of Eurycoma longifolia Jack supplementation on eccentric leg press exercise-induced muscle damage in rugby players
    Zakaria AZ, Washif JA, Lim BH, Nosaka K
    Biol Sport, 2023 Jul;40(3):691-697.
    PMID: 37398958 DOI: 10.5114/biolsport.2023.119290
    Eurycoma longifolia Jack (ELJ) is a herbal plant that has androgenic and antioxidant effects. We investigated the short-term effect of ELJ supplementation on muscle damage induced by eccentric exercise. Eighteen young (19-25 years), well-trained rugby 7s players were assigned to an ELJ or a placebo (PLA) group (n = 9/group). Each participant took four 100-mg capsules a day for seven days prior to performing a leg press eccentric exercise to failure in a double-blind fashion. Peak force, peak power and jump height in countermovement jump (CMJ), drop jump reactive strength index (RSI), muscle soreness assessed by a 100-mm visual analogue scale, plasma creatine kinase (CK) activity, and salivary hormones were measured at 24 h before and 0.5, 24, 48, 72, and 96 h after the exercise. Changes in the variables over time were compared between the groups by two-factor mixed-design ANOVA. The number of eccentric contractions performed was similar (P = 0.984) between the ELJ (21 ± 5) and PLA groups (21 ± 5). Salivary testosterone and cortisol concentrations did not change (P > 0.05) after the supplementation for both groups. CMJ peak power (-9.4 ± 5.6%) and height (-10.6 ± 4.9%), and RSI (-15.2 ± 16.2%) decreased at 24 h after exercise (P < 0.05), and muscle soreness (peak: 89 ±10 mm) and plasma CK activity (peak: 739 ± 420 IU/L) increased after exercise (P < 0.05) without significant differences between groups. These results showed that 7-day ELJ supplementation prior to the leg press eccentric exercise had no significant effects on hormones, performance and muscle damage markers for the athletes.
  14. Analysis of Entamoeba histolytica Membrane Proteome Using Three Extraction Methods
    Ujang J, Sani AAA, Lim BH, Noordin R, Othman N
    Proteomics, 2018 12;18(23):e1700397.
    PMID: 30284757 DOI: 10.1002/pmic.201700397
    Entamoeba histolytica membrane proteins are important players toward the pathogenesis of amoebiasis, but the roles of most of the proteins are not fully understood. Since efficient protein extraction method is crucial for a successful MS analysis, three extractions methods are evaluated for the use in studying the membrane proteome of E. histolytica: Two commercial kits (ProteoExtract from Calbiochem and ProteoPrep from Sigma), and a conventional laboratory method. The results show that ProteoExtract and the conventional method gave higher protein yields compared to ProteoPrep. LC-ESI-MS/MS identifies 456, 482, and 551 membrane fraction proteins extracted using ProteoExtract, ProteoPrep, and a conventional method, respectively. In silico analysis predicts 108 (21%), 235 (45%), and 177 (34%) membrane proteins from the extracts of ProteoExtract, ProteoPrep, and the conventional method, respectively. Furthermore, analysis of the cytosolic and membrane fractions shows the highest selectivity of the membrane proteins using the ProteoPrep extraction kit. Overall, this study reports 828 E. histolytica membrane fraction proteins that include 249 predicted membrane proteins. The data are available via ProteomeXchange with identifier PXD010171.
  15. Specificity and sensitivity of a rapid dipstick test (Brugia Rapid) in the detection of Brugia malayi infection
    Rahmah N, Taniawati S, Shenoy RK, Lim BH, Kumaraswami V, Anuar AK, et al.
    Trans R Soc Trop Med Hyg, 2002 1 31;95(6):601-4.
    PMID: 11816429
    A total of 753 serum samples from 6 institutions in 3 countries (Malaysia, Indonesia and India) were used to evaluate an immunochromatographic rapid dipstick test, Brugia Rapid, for diagnosis of Brugia malayi infection. The samples comprised sera from 207 microfilaria-positive individuals and 546 individuals from filaria non-endemic areas. The latter consisted of 70 individuals with soil-transmitted helminth infections, 68 with other helminth infections, 238 with protozoan infections, 12 with bacterial and viral infections and 158 healthy individuals. The dipstick is prepared with a goat anti-mouse antibody control line and a B. malayi recombinant-antigen test line. First, the dipstick is dipped into a well containing diluted patient serum, thus allowing specific anti-filarial antibody in the serum to react with the recombinant antigen. Then the dipstick is placed into an adjacent well containing reconstituted anti-human IgG4-gold. After 10 min, development of 2 red-purplish lines denotes a positive result and one line indicates a negative reaction. The overall results of the evaluation showed 97% sensitivity, 99% specificity, 97% positive predictive value and 99% negative predictive value. Brugia Rapid is thus a promising diagnostic tool for detection of B. malayi infection, and would be especially useful for the brugian filariasis elimination programme.
  16. A recombinant antigen-based IgG4 ELISA for the specific and sensitive detection of Brugia malayi infection
    Rahmah N, Lim BH, Khairul Anuar A, Shenoy RK, Kumaraswami V, Lokman Hakim S, et al.
    Trans R Soc Trop Med Hyg, 2001 8 9;95(3):280-4.
    PMID: 11490997
    An IgG4 ELISA based on a novel recombinant antigen was evaluated for detection of Brugia malayi infection, using 2487 sera from various institutions: 2031 samples from Universiti Sains Malaysia, 276 blinded sera from 2 other institutions in Malaysia, 140 blinded sera from India and 40 blinded sera from Thailand. These sera were from various groups of individuals, i.e., microfilaraemics, chronic patients, endemic normals, non-endemic normals and individuals with other parasitic and bacterial infections. Based on a cut-off optical density reading of 0.300, the IgG4 ELISA demonstrated specificity rates of 95.6-100%, sensitivity rates of 96-100%, positive predictive values of 75-100% and negative predictive values of 98.9-100%. These evaluation studies demonstrated the high specificity and sensitivity of this test for the detection of active B. malayi infection. Thus, the IgG4 ELISA would be very useful as a tool in diagnosis and in elimination programmes for brugian filariasis.
  17. Fulltext Intrinsic and extrinsic motivation among adolescent ten-pin bowlers in kuala lumpur, malaysia
    Teo EW, Khoo S, Wong R, Wee EH, Lim BH, Rengasamy SS
    J Hum Kinet, 2015 Mar 29;45:241-51.
    PMID: 25964827 DOI: 10.1515/hukin-2015-0025
    Motivation has long been associated with sports engagement. However, to date no research has been performed to understand the domain of motivation among ten-pin bowlers. The purpose of this study was to investigate different types of motivation (i.e., intrinsic vs. extrinsic) based on self-determination theory from the perspective of gender and the bowler type (competitive vs. casual). A total of 240 bowlers (104 male, 136 female; 152 competitive, 88 casual) with a mean age of 16.61 ± 0.78 years were recruited in Kuala Lumpur. The Sport Motivation Scale, a 28-item self-report questionnaire measuring seven subscales (i.e., intrinsic motivation to know, intrinsic motivation to accomplish, intrinsic motivation to experience stimulation, extrinsic motivation to identify regulation, extrinsic motivation for introjection regulation, extrinsic motivation to external regulation, and amotivation) was administered. Results showed significant differences (t=10.43, df=239, p=0.01) between total scores of intrinsic and extrinsic motivation among ten-pin bowlers. There were significant gender differences with respect to intrinsic motivation to know, intrinsic motivation to accomplish, intrinsic motivation to experience stimulation, and extrinsic motivation to identify regulation. However, no significant bowler type differences were found for either the intrinsic (t=-1.15, df=238, p=0.25) or extrinsic (t=-0.51, df=238, p=0.61) motivation dimensions. In conclusion, our study demonstrated substantial intrinsic motivation for gender effects, but no bowler type effects among adolescent ten-pin bowlers.
  18. Short communication: use of a recombinant antigen-based ELISA to determine prevalence of brugian filariasis among Malaysian schoolchildren near Pasir Mas, Kelantan-Thailand border
    Rahmah N, Lim BH, Azian H, Ramelah TS, Rohana AR
    Trop Med Int Health, 2003 Feb;8(2):158-63.
    PMID: 12581442
    Brugian filariasis infects 13 million people in Asia. The routine prevalence survey method using night thick blood smear is not sensitive enough to reflect the actual infection prevalence. In 1997-2001, only three microfilaraemic cases (of 5601 individuals screened; 0.05%) were reported in Pasir Mas, a district in Kelantan (Malaysia), which shares a border with Thailand. We therefore investigated the infection prevalence in this district by employing a sensitive and specific serological assay (Brugia-Elisa). This test is based on detection of specific IgG4 antibody against a Brugia malayi recombinant antigen. A total of 5138 children, aged 7-12 years, from 16 primary schools, were tested. Eighteen pupils in eight schools, located in five subdistricts, tested positive, giving an overall prevalence rate of 0.35%. Infection in these children is significant as they represent more recent cases. These subdistricts should be included in the national filariasis elimination programme.
  19. Unusual metal ion cofactor requirement of Entamoeba histolytica choline and ethanolamine kinase isoforms
    Chang CH, Few LL, Lim BH, Yvonne-Tee GB, Chew AL, See Too WC
    Parasitol Res, 2023 Jul;122(7):1651-1661.
    PMID: 37202563 DOI: 10.1007/s00436-023-07869-5
    The de novo biosynthesis of phosphatidylcholine and phosphatidylethanolamine in Entamoeba histolytica is largely dependent on the CDP-choline and CDP-ethanolamine pathways. Although the first enzymes of these pathways, EhCK1 and EhCK2, have been previously characterized, their enzymatic activity was found to be low and undetectable, respectively. This study aimed to identify the unusual characteristics of these enzymes in this deadly parasite. The discovery that EhCKs prefer Mn2+ over the typical Mg2+ as a metal ion cofactor is intriguing for CK/EK family of enzymes. In the presence of Mn2+, the activity of EhCK1 increased by approximately 108-fold compared to that in Mg2+. Specifically, in Mg2+, EhCK1 exhibited a Vmax and K0.5 of 3.5 ± 0.1 U/mg and 13.9 ± 0.2 mM, respectively. However, in Mn2+, it displayed a Vmax of 149.1 ± 2.5 U/mg and a K0.5 of 9.5 ± 0.1 mM. Moreover, when Mg2+ was present at a constant concentration of 12 mM, the K0.5 value for Mn2+ was ~ 2.4-fold lower than that in Mn2+ alone, without affecting its Vmax. Although the enzyme efficiency of EhCK1 was significantly improved by about 25-fold in Mn2+, it is worth noting that its Km for choline and ATP were higher than in equimolar of Mg2+ in a previous study. In contrast, EhCK2 showed specific activity towards ethanolamine in Mn2+, exhibiting Michaelis-Menten kinetic with ethanolamine (Km = 312 ± 27 µM) and cooperativity with ATP (K0.5 = 2.1 ± 0.2 mM). Additionally, we investigated the effect of metal ions on the substrate recognition of human choline and ethanolamine kinase isoforms. Human choline kinase α2 was found to absolutely require Mg2+, while choline kinase β differentially recognized choline and ethanolamine in Mg2+ and Mn2+, respectively. Finally, mutagenesis studies revealed that EhCK1 Tyr129 was critical for Mn2+ binding, while Lys233 was essential for substrate catalysis but not metal ion binding. Overall, these findings provide insight into the unique characteristics of the EhCKs and highlight the potential for new approaches to treating amoebiasis. Amoebiasis is a challenging disease for clinicians to diagnose and treat, as many patients are asymptomatic. However, by studying the enzymes involved in the CDP-choline and CDP-ethanolamine pathways, which are crucial for de novo biosynthesis of phosphatidylcholine and phosphatidylethanolamine in Entamoeba histolytica, there is great potential to discover new therapeutic approaches to combat this disease.
  20. Brugia malayi infection in Meriones unguiculatus: antibody response to recombinant BmR1
    Lim BH, Noordin R, Nor ZM, Rahman RA, Abdullah KA, Sinnadurai S
    Exp Parasitol, 2004 Sep-Oct;108(1-2):1-6.
    PMID: 15491542
    BmR1 recombinant antigen has previously been shown to demonstrate high sensitivity and specificity in the serological diagnosis of brugian filariasis in humans. In this study, the pattern of recognition of antibody to BmR1 during Brugia malayi infection was investigated by employing Meriones unguiculatus as the experimental model. Thirty two gerbils were infected subcutaneously with 120 L(3); and two control groups each comprising 25 animals were employed. ELISA using BmR1 was used to detect filaria-specific IgG antibodies elicited by the gerbils; using sera collected from the day 1 until day 150 post-inoculation (p.i.). The results showed that BmR1 detected B. malayi infection in gerbils harboring adult worms irrespective of the presence of circulating microfilaria, and was exemplified by positive ELISA results in nine a microfilaraemic animals that harbored live adult worms. The initial time of the antibody recognition was at day 8 p.i. and the antibody titre showed some correlation with adult worm burden.
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