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  1. A Brugia malayi antigen specifically recognized by infected individuals
    Rahmah N, Anuar AK, A'shikin AN, Lim BH, Mehdi R, Abdullah B, et al.
    Biochem Biophys Res Commun, 1998 Sep 29;250(3):586-8.
    PMID: 9784388
    Western blot analyses were performed on 444 serum specimens: 40 sera from microfilaraemic individuals, 10 sera from elephantiasis patients, 24 treated individuals, 50 sera from residents of endemic areas without anti-filarial IgG4 antibodies (endemic normals), 20 sera from amicrofilaraemic individuals with high anti-filarial IgG4 antibodies, 200 sera from healthy city-dwellers (non-endemic samples), and 100 sera from soil-transmitted helminth-infected individuals. Phast electrophoresis system was used to electrophorese Brugia malayi soluble adult worm antigen on 10-15% SDS-PAGE gradient gels followed by electrophoretic transfer onto PVDF membranes. Membrane strips were then successively incubated with blocking solution, human sera, and monoclonal anti-human IgG4 antibody-HRP, with adequate washings done in between each incubation step. Luminol chemiluminescence detection was then used to develop the blots. An antigenic band with the MW of approximately 37 kDa was found to be consistently present in the Western blots of all microfilaraemic sera, all amicrofilaraemic sera with high titres of anti-filarial IgG4 antibodies, some treated patients, and some elephantiasis patients. The antigen did not occur in immunoblots of individuals with other helminthic infections, normal endemic individuals, and city dwellers. Therefore the B. malayi antigen of with the MW of approximately 37 kDa demonstrated specific reactions with sera of B. malayi-infected individuals and thus may be useful for diagnostic application.
  2. 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.
  3. 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.
  4. 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.
  5. 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.
  6. 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.
  7. 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.
  8. 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.
  9. 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.
  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 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.
  14. 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.
  15. 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.
  16. 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.
  17. Fulltext A case study of illicit preparation of antirheumatic analgesic with phenylbutazone as active ingredient
    Chang ET, Lim BH
    Med J Malaysia, 1989 Jun;44(2):160-6.
    PMID: 2626126
    The abuse of phenylbutazone among rheumatoid arthritis patients has recently become a subject of interest. Unscrupulous manufacturers take advantage of the miraculous analgesic property of phenylbutazone and deliberately add this toxic drug in their preparations without declaring its presence on the label. In a recent survey, many such illicit preparations were seized from Chinese medical halls in Johor and sent to the Department of Chemistry, Johor Bahru for analysis. Here a Gas Chromatograph Mass Selective Detector (GC-MSD) method was developed for the determination of phenylbutazone in illicit traditional preparations.
  18. Selection of suitable pedicle screw for degenerated cortical and cancellous bone of human lumbar spine: A finite element study
    Jain P, Sing Ngie DC, Lim SF, Lim BH
    Int J Artif Organs, 2020 Oct 13.
    PMID: 33045876 DOI: 10.1177/0391398820964483
    Pedicular arthrodesis is the traditional procedure in terms of increase in the biomechanical stability with higher fixation rate. The current work aims to identify the effect of three spinal pedicle screws considering cortical and cancellous degeneracy condition. Lumbar section L2-L3 is utilized and various load and moment conditions were applied to depict the various biomechanical parameters for selection of suitable screw. Three dimensional model is considered in finite element analysis to identify the various responses of pedicle screw at bone screw juncture. Computed tomography (CT) images of a healthy male were considered to generate the finite element vertebral model. Generated intact model was further utilized to develop the other implanted models of degenerated cortical and cancellous bone models. The three fused instrumented models with different cortical and cancellous degeneracy conditions were analyzed in finite element analysis. The results were obtained as stress pattern at bone screw boundary and intervertebral disc stress. FE simulated results represents significant changes in the von Mises stress due to various load and moment conditions on degenerated bones during different body movement conditions. Results have shown that among all pedicle screws, the 6.0 mm diameter screw reflects very less stress values at the juncture. Multiple results on biomechanical aspects obtained during the FE study can be considered to design a new stabilization device and may be helpful to plan surgery of critical sections.
  19. Parasitic infections in Malaysian aborigines with pulmonary tuberculosis: a comparative cross-sectional study
    Wong WK, Mohd-Nor N, Noordin R, Foo PC, Mohamed Z, Haq JA, et al.
    Parasitol Res, 2019 Sep;118(9):2635-2642.
    PMID: 31363922 DOI: 10.1007/s00436-019-06406-7
    The geographical distribution of tuberculosis (TB) overlaps with various parasitic infections. Uncovering the characteristics of coinfecting parasites that potentially affect the host susceptibility to TB is pertinent as it may provide input to current TB therapeutic and prophylactic measures. The present study was aimed at examining the types of parasitic infections in TB patients and healthy TB contacts (HC) in Orang Asli, Malaysian aborigines, who dwelled in the co-endemic areas. Stool and serum samples were collected from Orang Asli who fulfilled the selection criteria and provided written informed consents. Selected parasitic infections in the two study groups were determined by stool examination and commercial serum antibody immunoassays. The prevalence of parasitic infections in TB and HC participants were 100% (n = 82) and 94.6% (n = 55) respectively. The parasitic infections comprised toxocariasis, trichuriasis, amoebiasis, toxoplasmosis, hookworm infection, ascariasis, strongyloidiasis, and brugian filariasis, in decreasing order of prevalence. Overall, helminth or protozoa infection did not show any significant association with the study groups. However, when the species of the parasite was considered, individuals exposed to trichuriasis and toxoplasmosis showed significant odds reduction (odds ratio (OR) 0.338; 95% confidence interval (CI) 0.166, 0.688) and odds increment (OR 2.193; 95% CI 1.051, 4.576) to have active pulmonary TB, respectively. In conclusion, trichuriasis and toxoplasmosis may have distinct negative and positive associations respectively with the increase of host susceptibility to TB.
  20. Fulltext Loop-mediated isothermal amplification (LAMP) reaction as viable PCR substitute for diagnostic applications: a comparative analysis study of LAMP, conventional PCR, nested PCR (nPCR) and real-time PCR (qPCR) based on Entamoeba histolytica DNA derived from faecal sample
    Foo PC, Nurul Najian AB, Muhamad NA, Ahamad M, Mohamed M, Yean Yean C, et al.
    BMC Biotechnol, 2020 Jun 22;20(1):34.
    PMID: 32571286 DOI: 10.1186/s12896-020-00629-8
    BACKGROUND: This study reports the analytical sensitivity and specificity of a Loop-mediated isothermal amplification (LAMP) and compares its amplification performance with conventional PCR, nested PCR (nPCR) and real-time PCR (qPCR). All the assays demonstrated in this study were developed based on Serine-rich Entamoeba histolytica protein (SREHP) gene as study model.

    RESULTS: A set of SREHP gene specific LAMP primers were designed for the specific detection of Entamoeba histolytica. This set of primers recorded 100% specificity when it was evaluated against 3 medically important Entamoeba species and 75 other pathogenic microorganisms. These primers were later modified for conventional PCR, nPCR and qPCR applications. Besides, 3 different post-LAMP analyses including agarose gel electrophoresis, nucleic acid lateral flow immunoassay and calcein-manganese dye techniques were used to compare their limit of detection (LoD). One E. histolytica trophozoite was recorded as the LoD for all the 3 post-LAMP analysis methods when tested with E. histolytica DNA extracted from spiked stool samples. In contrast, none of the PCR method outperformed LAMP as both qPCR and nPCR recorded LoD of 100 trophozoites while the LoD of conventional PCR was 1000 trophozoites.

    CONCLUSIONS: The analytical sensitivity comparison among the conventional PCR, nPCR, qPCR and LAMP reveals that the LAMP outperformed the others in terms of LoD and amplification time. Hence, LAMP is a relevant alternative DNA-based amplification platform for sensitive and specific detection of pathogens.

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