Displaying publications 1 - 20 of 45 in total

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  1. Lee HY, Jayalakshmi P, Noori SH
    Med J Malaysia, 1993 Mar;48(1):17-27.
    PMID: 8341168
    A 1 year review of 529 cases of acute appendicitis, treated at the University Hospital in 1990, was performed. Perforation rate was 23.7% and delay in diagnosis was found to be significant. Patients above 50 years of age were particularly at risk. Diagnostic error was 19.3% and it was a problem not only in young women but also in children. Temperature and rectal examinations were not found to be helpful in the diagnosis in contrast to leukocytosis. Waiting time for operation was long (median 7 hours), be it for a perforated or a nonperforated appendicitis.
  2. Lee HY, Subramaniam N, Nordin MM
    Singapore Med J, 1996 Feb;37(1):55-60.
    PMID: 8783915
    To compare the advantages and disadvantages of the New Bird metal cups and silicone cups in terms of maternal and foetal outcome. To study the adverse effects and factors associated with failed vacuum deliveries.
  3. Lee HY
    Singapore Med J, 1997 Jul;38(7):292-4.
    PMID: 9339095
    Dinoprostone, is presently used in our standard protocol for cervical ripening and labour induction. In search for a cheaper alternative, misoprostol has been found to be a good substitute. In view of the potential saving it might offer, we set out to test its efficacy against the standard dinoprostone.
  4. Tan KB, Lee HY, Putti TC
    ANZ J Surg, 2002 Nov;72(11):793-7.
    PMID: 12437689
    Breast ductal carcinoma in-situ (DCIS) is increasingly being diagnosed as a result of screening mammography and better pathological recognition. With this and the rising breast cancer incidence in Singapore, DCIS is poised to become a bigger part of surgical practice. Principles of screening, diagnosis and management of DCIS have also been rapidly evolving. Against this background, a clinicopathological audit of recent cases of DCIS in our centre was performed.
  5. Lee HY, Stephen A, Sushela D, Mala M
    Trop Biomed, 2008 Aug;25(2):134-9.
    PMID: 18948884
    Parasites and bacteria are reported in the faeces of birds in the current study. Fresh faecal samples of the large-billed crow (Corvus spp.) were collected from the study site at Bangsar, an urban setting in Kuala Lumpur, Malaysia. These samples were transported to laboratory and analysed for parasites and bacteria. Pre-prepared XLD agar plates were used for culturing the bacteria in the laboratory. Using the API 20ETM Test Strips, 9 different species of bacteria were identified belonging to the family Enterobacteriacea. They were Citrobacter freundii, Enterobacter cloacae, Proteus mirabilis, Klebsiella pneumoniae, Kluyvera ascorbata, Salmonella arizonae, Salmonella typhi, Shigella flexneri and Shigella sonnei. The protozoan parasites detected include Cryptosporidium spp., Cyclospora spp., Blastocystis spp., and Capillaria hepatica and Ascaris lumbricoidus ova. Environmental air samples collected on agar plates using an air sampler in the area only produced fungal colonies. Some of these pathogens found in the crows are of zoonotic importance, especially Cryptosporidium, Blastocystis, Cyclopsora, Salmonella, Shigella and Kluyvera. The finding of Kluyvera spp. in crows in our current study highlights its zoonotic potential in an urban setting.
  6. Chai LC, Lee HY, Ghazali FM, Abu Bakar F, Malakar PK, Nishibuchi M, et al.
    J Food Prot, 2008 Dec;71(12):2448-52.
    PMID: 19244897
    Campylobacter jejuni was found to occur at high prevalence in the raw salad vegetables examined. Previous reports describe cross-contamination involving meat; here we investigated the occurrence of cross-contamination and decontamination events in the domestic kitchen via C. jejuni-contaminated vegetables during salad preparation. This is the first report concerning quantitative cross-contamination and decontamination involving naturally contaminated produce. The study was designed to simulate the real preparation of salad in a household kitchen, starting with washing the vegetables in tap water, then cutting the vegetables on a cutting board, followed by slicing cucumber and blanching (heating in hot water) the vegetables in 85 degrees C water. Vegetables naturally contaminated with C. jejuni were used throughout the simulation to attain realistic quantitative data. The mean of the percent transfer rates for C. jejuni from vegetable to wash water was 30.1 to 38.2%; from wash water to cucumber, it was 26.3 to 47.2%; from vegetables to cutting board, it was 1.6 to 10.3%; and from cutting board to cucumber, it was 22.6 to 73.3%. The data suggest the wash water and plastic cutting board as potential risk factors in C. jejuni transmission to consumers. Washing of the vegetables with tap water caused a 0.4-log reduction of C. jejuni attached to the vegetables (most probable number/gram), while rapid blanching reduced the number of C. jejuni organisms to an undetectable level.
  7. Chai LC, Ghazali FM, Bakar FA, Lee HY, Suhaimi LR, Talib SA, et al.
    J Microbiol Biotechnol, 2009 Nov;19(11):1415-20.
    PMID: 19996696
    The aim of the present study was to examine the prevalence of thermophilic Campylobacter spp. (Campylobacter jejuni and Campylobacter coli) in soil, poultry manure, irrigation water, and freshly harvested vegetables from vegetable farms in Malaysia. C. jejuni was detected in 30.4% and 2.7% of the soil samples, 57.1% and 0% of the manure samples, and 18.8% and 3% of the vegetable samples from farm A and farm B, respectively, when using the MPNPCR method. Campylobacter spp. was not found in any of the irrigation water samples tested. Therefore, the present results indicate that the aged manure used by farm A was more contaminated than the composted manure used by farm B. Mostly, the leafy and root vegetables were contaminated. C. coli was not detected in any of the samples tested in the current study. Both farms tested in this study were found to be contaminated by campylobacters, thereby posing a potential risk for raw vegetable consumption in Malaysia. The present results also provide baseline data on Campylobacter contamination at the farm level.
  8. Pui CF, Wong WC, Chai LC, Lee HY, Noorlis A, Zainazor TC, et al.
    Trop Med Health, 2011 Mar;39(1):9-15.
    PMID: 22028607 DOI: 10.2149/tmh.2010-20
    Salmonellosis outbreaks involving typhoid fever and human gastroenteritis are important diseases in tropical countries where hygienic conditions are often not maintained. A rapid and sensitive method to detect Salmonella spp., Salmonella Typhi and Salmonella Typhimurium is needed to improve control and surveillance of typhoid fever and Salmonella gastroenteritis. Our objective was the concurrent detection and differentiation of these food-borne pathogens using a multiplex PCR. We therefore designed and optimized a multiplex PCR using three specific PCR primer pairs for the simultaneous detection of these pathogens. The concentration of each of the primer pairs, magnesium chloride concentration, and primer annealing temperature were optimized before verification of the specificity of the primer pairs. The target genes produced amplicons at 429 bp, 300 bp and 620 bp which were shown to be 100% specific to each target bacterium, Salmonella spp., Salmonella Typhi and Salmonella Typhimurium, respectively.
  9. Chan CK, Lee HY, Choi WC, Cho JY, Lee SH
    Eur Spine J, 2011 Jul;20 Suppl 2:S217-21.
    PMID: 20938789 DOI: 10.1007/s00586-010-1585-5
    Sciatica-like leg pain can be the main presenting symptom in patients with cervical cord compression. It is a false localizing presentation, which may lead to missed or delayed diagnosis, resulting in the wrong plan of management, especially in the presence of concurrent lumbar lesions. Medical history, physical findings and the results of imaging studies were reviewed in two cases of cervical cord compressions, which presented with sciatica-like leg pain. There was multi-level cervical spondylosis with cord compression in the first patient and the second patient had two levels of cervical disc herniation with cord compression. In both cases, there were co-existing lumbar lesions, which could be responsible for the presentation of the leg pain. Cervical blocks were diagnostic in identifying the level responsible for the leg pain and it was confirmed so after cervical decompressive surgery in both cases, which brought significant pain relief. Funicular leg pain is a rare presentation of cervical cord compression. It is a referred pain due to the irritation of the ascending spinothalamic tract. Cervical blocks were successful in identifying the cause of funicular pain in our cases and this may pave the way for further studies to establish the role of cervical blocks as a diagnostic tool for funicular pain caused by cord compression.
  10. Lee HY, Chai LC, Pui CF, Wong WC, Mustafa S, Cheah YK, et al.
    J Microbiol Biotechnol, 2011 Sep;21(9):954-9.
    PMID: 21952372
    There have been a number of studies conducted in order to compare the efficiencies of recovery rates, utilizing different protocols, for the isolation of L. monocytogenes. However, the severity of multiple cell injury has not been included in these studies. In the current study, L. monocytogenes ATCC 19112 was injured by exposure to extreme temperatures (60°C and -20°C) for a one-step injury, and for a two-step injury the cells were transferred directly from a heat treatment to frozen state to induce a severe cell injury (up to 100% injury). The injured cells were then subjected to the US Food and Drug Administration (FDA), the ISO-11290, and the modified United States Department of Agriculture (mUSDA) protocols, and plated on TSAyeast (0.6% yeast), PALCAM agar, and CHROMAgar Listeria for 24 h or 48 h. The evaluation of the total recovery of injured cells was also calculated based on the costs involved in the preparation of media for each protocol. Results indicate that the mUSDA method is best able to aid the recovery of heat-injured, freeze-injured, and heat-freeze-injured cells and was shown to be the most cost effective for heat-freeze-injured cells.
  11. Lee HY, Chai LC, Pui CF, Mustafa S, Cheah YK, Nishibuchi M, et al.
    Braz J Microbiol, 2013;44(1):51-5.
    PMID: 24159283 DOI: 10.1590/S1517-83822013005000004
    Biofilm formation can lead to various consequences in the food processing line such as contamination and equipment breakdowns. Since formation of biofilm can occur in various conditions; this study was carried out using L. monocytogenes ATCC 19112 and its biofilm formation ability tested under various concentrations of sodium chloride and temperatures. Cultures of L. monocytogenes ATCC 19112 were placed in 96-well microtitre plate containing concentration of sodium chloride from 1-10% (w/v) and incubated at different temperature of 4 °C, 30 °C and 45 °C for up to 60 h. Absorbance reading of crystal violet staining showed the density of biofilm formed in the 96-well microtitre plates was significantly higher when incubated in 4 °C. The formation of biofilm also occurs at a faster rate at 4 °C and higher optical density (OD 570 nm) was observed at 45 °C. This shows that storage under formation of biofilm that may lead to a higher contamination along the processing line in the food industry. Formation of biofilm was found to be more dependent on temperature compared to sodium chloride stress.
  12. Ismail R, Lee HY, Mahyudin NA, Abu Bakar F
    J Food Drug Anal, 2014 Dec;22(4):407-412.
    PMID: 28911453 DOI: 10.1016/j.jfda.2014.01.026
    In this study, linear relationships between response and concentration were used to estimate the detection limit (DL) and quantification limit (QL) for five avermectins: emamectin, abamectin, doramectin, moxidectin, and ivermectin. Estimation of DL and QL was based on the standard deviation of residual and y-intercept of the regression line at low concentrations of avermectins, using the dispersive solid-phase extraction procedure. Avermectin extracts were analyzed using liquid chromatography tandem mass spectrometry. Based on the regression slope, DL and QL were higher at concentrations of 0.3-0.4 μg/kg and 1 μg/kg, respectively, for all avermectin compounds. Linearity assessment was performed by linear regression, which incorporated a regression model, outlier rejection, and evaluation of the assumption with a significant test. For all avermectins, there is a significant correlation between response and concentration in the range 1-15 μg/kg, and the y-intercept passes through origin (zero).
  13. Lee HY, Nyon MP, Strych U
    Curr Trop Med Rep, 2016;3(3):80-86.
    PMID: 32226714 DOI: 10.1007/s40475-016-0084-0
    Various types of vaccines are under pre-clinical and clinical development to address the recent appearance of Middle East respiratory syndrome or MERS, an emerging infectious disease that has already caused over 600 deaths and remains a threat to world health. The causative agent for this respiratory disease is a member of the betacoronavirus genus, phylogenetically closely related to the SARS coronavirus that caused an international health emergency in 2002. With lessons learned from the outbreak of severe acute respiratory syndrome, and with undeniable technological advances, vaccine development against MERS was initially fast-paced and has produced several DNA and protein vaccine candidates with promising results during early pre-clinical testing. At least one vaccine candidate has even entered first-in-humans clinical trials now. With the number of MERS cases declining though and other infectious diseases attracting increased attention, the question remains, whether, similar to the situation after the SARS pandemic, vaccine development is halted or remains the priority it rightfully should.
  14. Khor CS, Mohd-Rahim NF, Hassan H, Chandren JR, Nore SS, Johari J, et al.
    Vector Borne Zoonotic Dis, 2018 03;18(3):131-137.
    PMID: 29336685 DOI: 10.1089/vbz.2017.2153
    Q fever is a disease caused by Coxiella burnetii. It is a disease of public health concern in many parts of the world. In this study, we described the seroprevalence of Q fever among selected populations of Orang Asli (OA), indigenous people, many of whom live within the forest fringe areas of Peninsular Malaysia. Serum samples were obtained from 887 OA participants from selected villages. Samples were analyzed for the presence of IgG antibodies reactive against C. burnetii by enzyme-linked immunosorbent assay. Statistical methods were used to identify possible associations between seropositivity for C. burnetii and a number of demographic variables obtained from the questionnaires. In total, 9.6% (n = 85/887) of the serum samples were reactive to C. burnetii. Statistical results suggest that elderly male OA residing in OA village, Bukit Payung, were most likely to be tested seropositive for C. burnetii. This study suggests that OA are at a significant risk of contracting C. burnetii infection, and both demographic and geographic factors are important contributors to this risk. Further prospective studies are needed to establish the true burden of C. burnetii infection within the indigenous population as well as within Peninsular Malaysia as a whole.
  15. Wang YH, Chen CB, Tassaneeyakul W, Saito Y, Aihara M, Choon SE, et al.
    Clin. Pharmacol. Ther., 2019 01;105(1):112-120.
    PMID: 29569740 DOI: 10.1002/cpt.1071
    Specific ethnic genetic backgrounds are associated with the risk of Stevens-Johnson syndrome / toxic epidermal necrolysis (SJS/TEN) especially in Asians. However, there have been no large cohort, multiple-country epidemiological studies of medication risk related to SJS/TEN in Asian populations. Thus, we analyzed the registration databases from multiple Asian countries who were treated during 1998-2017. A total 1,028 SJS/TEN cases were identified with the algorithm of drug causality for epidermal necrolysis. Furthermore, those medications labeled by the US Food and Drug Administration (FDA) as carrying a risk of SJS/TEN were also compared with the common causes of SJS/TEN in Asian countries. Oxcarbazepine, sulfasalazine, COX-II inhibitors, and strontium ranelate were identified as new potential causes. In addition to sulfa drugs and beta-lactam antibiotics, quinolones were also a common cause. Only one acetaminophen-induced SJS was identified, while several medications (e.g., oseltamivir, terbinafine, isotretinoin, and sorafenib) labeled as carrying a risk of SJS/TEN by the FDA were not found to have caused any of the cases in the Asian countries investigated in this study.
  16. Khor CS, Hassan H, Mohd-Rahim NF, Chandren JR, Nore SS, Johari J, et al.
    J Infect Dev Ctries, 2019 05 31;13(5):449-454.
    PMID: 32053515 DOI: 10.3855/jidc.11001
    INTRODUCTION: Lyme disease has been well-described in the North America and European countries. However, information is still very limited in the developing countries including Malaysia. The Orang Asli (OA), the indigenous people of Peninsular Malaysia reside mostly in the forest and forest fringe areas abundant with the vector for Lyme disease. Here, we described the seroprevalence of Borellia burgdorferi (B. burgdorferi) among the OA and demographic variables that could be associated with seroprevalence.

    METHODOLOGY: A total of 16 OA villages distributed across 8 states in Peninsular Malaysia participated in this study. Sera obtained from 904 OA volunteers were screened for anti-B. burgdorferi IgG antibodies. ELISA results obtained and demographic information collected were analysed to identify possible variables associated with seroprevalence.

    RESULTS: A total of 73 (8.1%) OA tested positive for anti-B. burgdorferi IgG antibodies. Among all the variables examined, village of residence (p = 0.045) was the only significant predictor for seropositivity. High (> 10.0%) prevalence was associated with three OA villages. Those living in one particular village were 1.65 times more likely to be seropositive as compared to other OA villages. Age, gender, marital status, household size, level of education, monthly household income and occupation were not significant predictors for seropositivity.

    CONCLUSION: Results of the present study support earlier findings that B. burgdorferi infection among Malaysians is currently under-recognized. Further studies will be needed at these locations to confirm the presence of Lyme disease among these populations.

  17. Nor FM, Lim JY, Tamin MN, Lee HY, Kurniawan D
    Polymers (Basel), 2020 Apr 14;12(4).
    PMID: 32295111 DOI: 10.3390/polym12040904
    The mechanics of damage and fracture process in unidirectional carbon fiber reinforced polymer (CFRP) composites subjected to shear loading (Mode II) were examined using the experimental method of the three-point end-notch flexure (3ENF) test. The CFRP composite consists of [0o]16 with an insert film in the middle plane for a starter defect. A 3ENF test sample with a span of 50 mm and interface delamination crack length of 12.5 mm was tested to yield the load vs. deformation response. A sudden load drop observed at maximum force value indicates the onset of delamination crack propagation. The results are used to extract the energy release rate, GIIC, of the laminates with an insert film starter defect. The effect of the starter defect on the magnitude of GIIC was examined using the CFRP composite sample with a Mode II delamination pre-crack. The higher magnitude of GIIC for the sample with insert film starter defect was attributed to the initial straight geometry of the notch/interface crack and the toughness of the resin at the notch front of the fabricated film insert. The fractured sample was examined using a micro-computerized tomography scanner to establish the shape of the internal delamination crack front. Results revealed that the interface delamination propagated in a non-uniform manner, leaving a curved-shaped crack profile.
  18. Khor CS, Mohd-Rahim NF, Hassan H, Tan KK, Zainal N, Teoh BT, et al.
    J Med Virol, 2020 08;92(8):956-962.
    PMID: 31814135 DOI: 10.1002/jmv.25649
    Dengue virus (DENV), Japanese encephalitis virus (JEV), and Zika virus (ZIKV) are mosquito-borne flavivirus of medical importance in tropical countries such as Malaysia. However, much remains unknown regarding their prevalence among the underserved indigenous people (Orang Asli) living in communities in the forest fringe areas of Peninsular Malaysia. Information on the prevalence of diseases is necessary to elevate the effectiveness of disease control and preventive measures. This study aimed to determine the seroprevalence of the three major flaviviruses among the Orang Asli and investigate the association between demographic factors and seropositivities. Sampling activities were conducted in the Orang Asli villages to obtain serum samples and demographic data from consenting volunteers. The presence of DENV, JEV, and ZIKV immunoglobulin G (IgG) antibodies in the sera were examined using commercial enzyme-linked immunosorbent assay kits. A focus reduction neutralization assay was performed to measure virus-specific neutralizing antibodies. A total of 872 serum samples were obtained from the Orang Asli volunteers. Serological assay results revealed that DENV IgG, JEV IgG, and ZIKV IgG seropositivities among the Orang Asli were at 4.9%, 48.4%, and 13.2%, respectively. Neutralizing antibodies (FRNT50 ≥ 1:40) against JEV and ZIKV were found in 86.7% and 100.0%, respectively, out of the samples tested. Positive serology to all three viruses corresponded significantly to the age of the volunteers with increasing seropositivity in older volunteers. Findings from the study suggest that Orang Asli are at significant risk of contracting JEV and ZIKV infections despite the lack of active transmission of the viruses in the country.
  19. Wong LP, Alias H, Wong PF, Lee HY, AbuBakar S
    Hum Vaccin Immunother, 2020 09 01;16(9):2204-2214.
    PMID: 32730103 DOI: 10.1080/21645515.2020.1790279
    BACKGROUND: The development of a vaccine against SARS-CoV-2 infection is on the way. To prepare for public availability, the acceptability of a hypothetical COVID-19 vaccine and willingness to pay (WTP) were assessed to provide insights into future demand forecasts and pricing considerations.

    METHODS: A cross-sectional survey was conducted from 3 to 12 April 2020. The health belief model (HBM) was used to assess predictors of the intent to receive the vaccine and the WTP.

    RESULTS: A total of 1,159 complete responses was received. The majority reported a definite intent to receive the vaccine (48.2%), followed by a probable intent (29.8%) and a possible intent (16.3%). Both items under the perceived benefits construct in the HBM, namely believe the vaccination decreases the chance of infection (OR = 2.51, 95% CI 1.19-5.26) and the vaccination makes them feel less worry (OR = 2.19, 95% CI 1.03-4.65), were found to have the highest significant odds of a definite intention to take the vaccine. The mean ± standard deviation (SD) for the amount that participants were willing to pay for a dose of COVID-19 vaccine was MYR$134.0 (SD±79.2) [US$30.66 ± 18.12]. Most of the participants were willing to pay an amount of MYR$100 [US$23] (28.9%) and MYR$50 [US$11.5] (27.2%) for the vaccine. The higher marginal WTP for the vaccine was influenced by no affordability barriers as well as by socio-economic factors, such as higher education levels, professional and managerial occupations and higher incomes.

    CONCLUSIONS: The findings demonstrate the utility of HBM constructs in understanding COVID-19 vaccination intention and WTP.

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