Displaying publications 21 - 40 of 90 in total

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  1. Tan L, Kamarulzaman A
    Biomed Imaging Interv J, 2006 Jan;2(1):e3.
    PMID: 21614220 MyJurnal DOI: 10.2349/biij.2.1.e3
    Tuberculosis (TB) is a well recognised occupational hazard for healthcare workers (HCWs). Concerns on the safety of healthcare settings in Malaysia was raised following a report of 25 HCWs working in 11 general hospitals in Malaysia who were infected with TB in 2004 being publicised in the media recently. As the disease burden in general is high in Malaysia, due attention should be given to this disease in our healthcare facilities including the radiology department, an often neglected area in TB infection control programmes. This article focuses on the key control measures that can be implemented in radiology departments in a developing country with limited resources.
  2. Chong YB, Tan LP, Robinson S, Lim SK, Ng KP, Keng TC, et al.
    Trop Biomed, 2012 Jun;29(2):270-6.
    PMID: 22735849 MyJurnal
    Penicilliosis is a rare occurrence among non human immunodeficiency virus (HIV) infected patients. We report here two cases of Penicillium marneffei infection in patients with systemic lupus erythematosus (SLE). Both patients had a recent flare of lupus and were on immunosuppressive drugs when they presented with prolonged fever without an obvious foci of infection, unresponsive to broad-spectrum antibiotics. They were leucopaenic upon admission, with rapid deterioration during the course of the illness. Diagnosis of penicilliosis via fungal isolation from blood culture was delayed resulting in the late initiation of antifungal agents. While both patients ultimately recovered, the delay in diagnosis led to a prolonged hospital stay with increased morbidity. Clinicians should be aware of this uncommon but emerging fungal pathogen in SLE patients and maintain a high index of suspicion in diagnosing this potentially fatal but treatable disease.
  3. Tan L, Ng SH, Omar A, Karupaiah T
    Child Obes, 2018 07;14(5):280-290.
    PMID: 29985649 DOI: 10.1089/chi.2018.0037
    BACKGROUND: Unhealthy food marketing to children is a key risk factor for childhood obesity. Online video platforms have surpassed television as the primary choice for screen viewing among children but the extent of food marketing through such media is relatively unknown. We aimed to examine food and beverage advertisements (ads) encountered in YouTube videos targeting children in Malaysia.

    METHODS: The social media analytics site SocialBlade.com was used to identify the most popular YouTube videos (n = 250) targeting children. Ads encountered while viewing these videos were recorded and analyzed for type of product promoted and ad format (video vs. overlay). Food and beverage ads were further coded based on food category and persuasive marketing techniques used.

    RESULTS: In total 187 ads were encountered in sampled videos. Food and beverage ads were the most common at 38% (n=71), among which 56.3% (n = 40) promoted noncore foods. Ads for noncore foods were more commonly delivered as video rather than overlay ads. Among ads promoting noncore foods, the most commonly employed persuasive marketing techniques found were taste appeal (42.3%), uniqueness/novelty (32.4%), the use of animation (22.5%), fun appeal (22.5%), use of promotional characters (15.5%), price (12.7%), and health and nutrition benefits (8.5%).

    CONCLUSIONS: Similar to television, unhealthy food ads predominate in content aimed toward children on YouTube. Policies regulating food marketing to children need to be extended to cover online content in line with a rapidly-evolving digital media environment. Service providers of social media can play a part in limiting unhealthy food advertising to children.

  4. Muhammad Iqbal AH, Lim SK, Ng KP, Tan LP, Chong YB, Keng TC
    Transpl Infect Dis, 2012 Aug;14(4):E23-6.
    PMID: 22551151 DOI: 10.1111/j.1399-3062.2012.00738.x
    Pneumocystis jirovecii (formerly Pneumocystis carinii) pneumonia (PCP) is a rare but serious infection that usually occurs within a year after solid organ transplantation. PCP may occur after 1 year post transplantation, but the rate is reported to be very low. Studies have shown an association between cytomegalovirus (CMV) infection in solid organ transplant patients and an increased risk of opportunistic infection. This increased risk is thought to be a result of the immunomodulatory effects of the CMV infection. We present a case of PCP infection occurring 13 years after a renal transplantation. This occurred following a recurrent CMV infection while the patient was on low-dose immunosuppressants.
  5. Tan LN, Gardener GJ, R Jeganathan JR, Naidu A, Hassan G, Ahmad Zainuddin R, et al.
    Med J Malaysia, 2023 Jan;78(1):68-73.
    PMID: 36715194
    INTRODUCTION: The authors aim to review the early outcomes of fetostopic laser ablation (FLA) to improve outcomes for twin-to-twin transfusion syndrome (TTTS) in an emerging national centre in Malaysia.

    MATERIALS AND METHODS: This is a retrospective cohort study of 17 monochorionic diamniotic (MCDA) twin pregnancies with severe TTTS treated by FLA over 15 months in a single centre by a single operator after performing simulations.

    RESULT: The overall survival rate at day 28 after birth for at least one twin was 76% while the dual-twin survival was 64%. The survival rates at day 28 after birth for at least one twin for stages II, III and IV were 90% vs 40% vs 100% (p=0.054) while dual survival rates were 80% vs 0% vs 100% (p=0.05), respectively. The rate of miscarriage was higher with anterior placentation compared to posterior placentation (33% vs 18%, p=0.660). There was one case of recurrent TTTS and no twin anaemia-polycythaemia sequence post-FLA. The fetal medicine unit in Ipoh is the national centre in Malaysia which covers the whole country, including the western coast of the Borneo Island (Sabah, Sarawak and Labuan) accessible only by air travel. All three cases from Borneo Island had resolved TTTS after FLA and dual neonatal survival at day 28 after birth.

    CONCLUSION: This data from an emerging new fetoscopic laser centre in Malaysia indicates results consistent with the published international learning curve and within the limits of good clinical governance.

  6. Zhang Y, Yu J, Tan L, Wang X, Li R, Kim DY
    J Microbiol, 2021 Nov;59(11):1044-1055.
    PMID: 34570337 DOI: 10.1007/s12275-021-1361-8
    Getah virus (GETV), which was first isolated in Malaysia in 1955, and Sagiyama virus (SAGV), isolated in Japan in 1956, are members of the genus Alphavirus in the family Togaviridae. It is a consensus view that SAGV is a variant of GETV. In the present study, we determined the complete sequences of the prototype GETV MM2021 and SAGV M6-Mag132 genomic RNA extracted from plaque-purified viruses. The MM2021 genome was 11,692 nucleotides (nt) in length in the absence of 3' poly(A) tail, and the length of M6-Mag132 genome was 11,698 nt. Through sequence alignment of MM2021 and M6-Mag132, we located all the amino acid differences between these two strains, which were scattered in all the encoded proteins. Subsequently, we validated the close evolutionary relationship between GETV and SAGV by constructing phylogenetic trees based on either complete genomes or structural genomes. We eventually analyzed the growth kinetics of GETV and SAGV as well as other representative alphaviruses in various mammalian and insect cell lines. It was shown that human-oriented cell lines such as HEK-293T and Hela cells were relatively resistant to GETV and SAGV infection due to absence of proviral factors or species-specific barrier. On the other hand, both GETV and SAGV replicated efficiently in non-human cell lines. Our results provide essential genetic information for future epidemiological surveillance on Alphaviruses and lay the foundation for developing effective interventions against GETV and SAGV.
  7. Tan LJ, Othman MS, Hiu J, Wong KT, Lai SK
    Malays J Pathol, 2021 Apr;43(1):81-85.
    PMID: 33903310
    BACKGROUND: Small bowel volvulus is defined as the torsion of the small intestine, potentially leading to bowel obstruction, gangrene and perforation. It is a rare condition, especially in adults.

    CASE PRESENTATION: A 30-year-old man was retrieved from the jungle with severe weight loss and abdominal symptoms. He succumbed to death despite 22 days of intensive medical treatment. An autopsy revealed a ruptured gangrenous ileal volvulus with peritonitis and subdiaphragmatic abscess. Further laboratory analysis detected systemic Candida tropicalis and intestinal gramnegative bacterial sepsis, systemic Zika virus viremia, leptospirosis complicating rhabdomyolysis and disseminated intravascular coagulopathy, Type I Herpes Simplex virus infection of the tongue and upper gastrointestinal tract. The cause of death was the ruptured ileal volvulus, complicated with upper gastrointestinal bleeding due to Herpes simplex virus esophagitis in a malnourished patient with resolving leptospirosis and underlying Zika virus co-infection.

    CONCLUSION: Rare clinical scenarios of adult-onset intestinal volvulus with concomitant multiple infections precludes clinical diagnosis and early treatment, leading to devastating consequences of clinical outcome. The positive clinical and postmortem correlation is a good learning lesson in many disciplines of medicine and science.

  8. Fong MY, Wong KT, Rohela M, Tan LH, Adeeba K, Lee YY, et al.
    Trop Biomed, 2010 Dec;27(3):447-50.
    PMID: 21399585 MyJurnal
    We report a case of unusual cutaneous toxoplasmosis manifestation in a HIV-positive patient. He presented with hard and painful nodular lesions on the arms, hands and chest. Serology tests for anti-Toxoplasma antibody were negative. However, histopathologic examination of the lesion revealed foci of macrophages containing crescent-shaped organisms resembling the zoites of the protozoan parasite Toxoplasma gondii. Ultrastructure examination under electron microscopy and PCR confirmed the organism as T. gondii.
  9. Fong SL, Lim KS, Tan L, Aris T, Khalid RA, Ali RA, et al.
    Epilepsy Behav, 2019 08;97:206-211.
    PMID: 31252280 DOI: 10.1016/j.yebeh.2019.05.033
    INTRODUCTION: Prevalence studies of epilepsy in Asia revealed a prevalence ranging from 1.5 to 14.0 per 1000 among Asian populations. However, the prevalence of epilepsy in Malaysia is not available for comparison with other countries. This study aimed to translate and validate a Malay brief screening instruments for ascertainment of epilepsy.

    METHOD: We translated into Malay a brief screening instrument for ascertainment of epilepsy designed and validated by Ottman et al., using the three-stage cross-cultural adaptation process developed by the International Quality of Life Assessment (IQOLA) project. We then administered the translated questionnaire via online survey to 162 cases (patients with epilepsy under follow-up care at the neurology clinic in University of Malaya Medical Centre, Kuala Lumpur) and 146 controls with no known history of epilepsy for validation.

    RESULTS: Applying the most liberal definition for a positive screen, we obtained a sensitivity of 96.3% (95% confidence interval [CI]: 91.8-98.5%), with a specificity of 66.4% (95% CI: 58.1-73.0%) and positive predictive value (PPV) of 2.0%. The most stringent definition for a positive screen (only epilepsy) resulted in a sensitivity of 97.4% (95% CI: 62.0-72.6%), specificity of 98.6% (95% CI: 94.6-99.7%), and PPV of 26.6%. Narrowing the definition of a positive screen decreased sensitivity but improved PPVs. When compared to the original English questionnaire, the sensitivities were similar for all four definitions of a positive screen.

    CONCLUSION: This is the first validated epilepsy screening questionnaire in the Malay language and represents a useful tool for the ascertainment of epilepsy in population-based studies.

  10. Hu W, Yu XG, Wu S, Tan LP, Song MR, Abdulahi AY, et al.
    J Helminthol, 2016 Jul;90(4):392-7.
    PMID: 26123649 DOI: 10.1017/S0022149X15000413
    Ancylostoma ceylanicum is a common zoonotic nematode. Cats act as natural reservoirs of the hookworm and are involved in transmitting infection to humans, thus posing a potential risk to public health. The prevalence of feline A. ceylanicum in Guangzhou (South China) was surveyed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). In total, 112 faecal samples were examined; 34.8% (39/112) and 43.8% (49/112) samples were positive with hookworms by microscopy and PCR method, respectively. Among them, 40.8% of samples harboured A. ceylanicum. Twelve positive A. ceylanicum samples were selected randomly and used for cox 1 sequence analysis. Sequencing results revealed that they had 97-99% similarity with A. ceylanicum cox 1 gene sequences deposited in GenBank. A phylogenetic tree showed that A. ceylanicum isolates were divided into two groups: one comprising four isolates from Guangzhou (South China), and the other comprising those from Malaysia, Cambodia and Guangzhou. In the latter group, all A. ceylanicum isolates from Guangzhou were clustered into a minor group again. The results indicate that the high prevalence of A. ceylanicum in stray cats in South China poses a potential risk of hookworm transmission from pet cats to humans, and that A. ceylanicum may be a species complex worldwide.
  11. Liew YM, McLaughlin RA, Chan BT, Abdul Aziz YF, Chee KH, Ung NM, et al.
    Phys Med Biol, 2015 Apr 7;60(7):2715-33.
    PMID: 25768708 DOI: 10.1088/0031-9155/60/7/2715
    Cine MRI is a clinical reference standard for the quantitative assessment of cardiac function, but reproducibility is confounded by motion artefacts. We explore the feasibility of a motion corrected 3D left ventricle (LV) quantification method, incorporating multislice image registration into the 3D model reconstruction, to improve reproducibility of 3D LV functional quantification. Multi-breath-hold short-axis and radial long-axis images were acquired from 10 patients and 10 healthy subjects. The proposed framework reduced misalignment between slices to subpixel accuracy (2.88 to 1.21 mm), and improved interstudy reproducibility for 5 important clinical functional measures, i.e. end-diastolic volume, end-systolic volume, ejection fraction, myocardial mass and 3D-sphericity index, as reflected in a reduction in the sample size required to detect statistically significant cardiac changes: a reduction of 21-66%. Our investigation on the optimum registration parameters, including both cardiac time frames and number of long-axis (LA) slices, suggested that a single time frame is adequate for motion correction whereas integrating more LA slices can improve registration and model reconstruction accuracy for improved functional quantification especially on datasets with severe motion artefacts.
  12. Diyana Jamaluddin N, Ibrahim N, Yuziana Mohd Yusof N, Ta Goh C, Ling Tan L
    Opt Laser Technol, 2023 Jan;157:108763.
    PMID: 36212170 DOI: 10.1016/j.optlastec.2022.108763
    The coronavirus disease (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) emerged as a major public health outbreak in late 2019 and was proclaimed a global pandemic in March 2020. A reflectometric-based RNA biosensor was developed by using cysteamine-stabilized gold nanoparticles (cysAuNPs) as the colorimetric probe for bioassay of COVID-19 RNA (SARS-CoV-2 RNA) sequence. The cysAuNPs aggregated in the presence of DNA probes via cationic and anionic electrostatic attraction between the positively charged cysteamine ligands and the negatively charged sugar-phosphate backbone of DNA, whilst in the presence of target RNAs, the specific recognition between DNA probes and targets depleted the electrostatic interaction between the DNA probes and cysAuNPs signal probe, leading to dispersed particles. This has rendered a remarkable shifting in the surface plasmon resonance (SPR) on the basis of visual color change of the RNA biosensor from red to purplish hue at the wavelength of 765 nm. Optical evaluation of SARS-CoV-2 RNA by means on reflectance transduction of the RNA biosensor based on cysAuNPs optical sensing probes demonstrated rapid response time of 30 min with high sensitivity, good linearity and high reproducibility across a COVID-19 RNA concentration range of 25 nM to 200 nM, and limit of detection (LOD) at 0.12 nM. qPCR amplification of SARS-CoV-2 viral RNA showed good agreement with the proposed RNA biosensor by using spiked RNA samples of the oropharyngeal swab from COVID-19 patients. Therefore, this assay is useful for rapid and early diagnosis of COVID-19 disease including asymptomatic carriers with low viral load even in the presence of co-infection with other viruses that manifest similar respiratory symptoms.
  13. Vijayan R, Tay KH, Tan LB, Loganathan
    Singapore Med J, 1994 Oct;35(5):502-4.
    PMID: 7701371
    One hundred and eighty-three patients undergoing surgery were interviewed twenty-four hours following surgery to assess the quality of pain relief they received in the immediate postoperative period. Interviews were conducted using a standard questionnaire for all patients. They were asked to (1) rate the quality of pain relief they obtained on a Visual Pain Analogue Scale (VPAS-0 being no pain and 10 being the worst imaginable pain); (2) state whether they were happy and satisfied with the pain relief they received; (3) if dissatisfied, they were asked to give their reasons. 37.7% (69 patients) had moderate to severe pain--pain score greater than 6 on the VPAS. Most of these patients had undergone abdominal or major orthopaedic surgery. 32.7% (60 patients) were unhappy with their postoperative pain control. The main reasons for complaint from the patients were that analgesic injections were either not given promptly or were not given at all. The survey also highlighted the inadequate under-administration of narcotic injections in the postoperative period despite orders being written up. It showed there is an urgent need for setting up an Acute Pain Service for better postoperative pain control. An anaesthesiology based Acute Pain Service was started in October 1992.
  14. Tan L, Wang M, Li X, Li H, Zhao J, Qu Y, et al.
    Bioresour Technol, 2016 Jan;200:572-8.
    PMID: 26539970 DOI: 10.1016/j.biortech.2015.10.079
    In this work, fractionation of empty fruit bunch (EFB) by bisulfite pretreatment was studied for the production of bioethanol and high value products to achieve biorefinery of EFB. EFB was fractionated to solid and liquor components by bisulfite process. The solid components were used for bioethanol production by quasi-simultaneous saccharification and fermentation. The liquor components were then converted to furfural by hydrolysis with sulfuric acid. Preliminary results showed that the concentration of furfural was highest at 18.8g/L with 0.75% sulfuric acid and reaction time of 25min. The conversion of xylose to furfural was 82.5%. Furthermore, we attempted to fractionate the liquor into hemicellulose sugars and lignin by different methods for producing potential chemicals, such as xylose, xylooligosaccharide, and lignosulfonate. Our research showed that the combination of bisulfite pretreatment and resin separation could effectively fractionate EFB components to produce bioethanol and other high value chemicals.
  15. Tan L, Sun W, Li X, Zhao J, Qu Y, Choo YM, et al.
    Biotechnol J, 2015 Jun;10(6):915-25.
    PMID: 25866127 DOI: 10.1002/biot.201400733
    Bisulfite pretreatment is a proven effective method for improving the enzymatic hydrolysis of empty fruit bunch (EFB) from oil palm for bioethanol production. In this study, we set out to determine the changes that occur in the structure and properties of EFB materials and fractions of hemicellulose and lignin during the bisulfite pretreatment process. The results showed that the crystallinity of cellulose in EFB increased after bisulfite pretreatment, whereas the EFB surface was damaged to various degrees. The orderly structure of EFB, which was maintained by hydrogen bonds, was destroyed by bisulfite pretreatment. Bisulfite pretreatment also hydrolyzed the glycosidic bonds of the xylan backbone of hemicellulose, thereby decreasing the molecular weight and shortening the xylan chains. The lignin fractions obtained from EFB and pretreated EFB were typically G-S lignin, and with low content of H units. Meanwhile, de-etherification occurred at the β-O-4 linkage, which was accompanied by polymerization and demethoxylation as a result of bisulfite pretreatment. The adsorption ability of cellulase differed for the various lignin fractions, and the water-soluble lignin fractions had higher adsorption capacity on cellulase than the milled wood lignin. In general, the changes in the structure and properties of EFB provided insight into the benefits of bisulfite pretreatment.
  16. Dahlia H, Tan LJ, Zarrahimah Z, Maria J
    Trop Biomed, 2009 Dec;26(3):341-5.
    PMID: 20237449 MyJurnal
    The isolation of Mycoplasma hyosynoviae from a piglet with severe pneumonia is described. This is the first report of M. hyosynoviae isolation in the country. The lung sample where the isolation was made was severely consolidated, suppurative and pleurisy. The pathogenicity of the M. hyosynoviae isolated has yet to be determined.
  17. Leong KH, Tan LL, Mustafa AM
    Chemosphere, 2007 Jan;66(6):1153-9.
    PMID: 17027062
    In Malaysia, rivers are the main source of public water supplies. This study was conducted from 2002 to 2003 to determine the levels of selected organochlorine and organophosphate pesticides in the Selangor River in Malaysia. Surface water samples have been collected seasonally from nine sites along the river. A liquid-liquid extraction followed by gas chromatography-mass spectrometry technique was used to determine the trace levels of these pesticide residues. The organochlorine pesticides detected were lindane, heptachlor, endosulfan, dieldrin, endosulfan sulfate, o,p'-DDT, p,p'-DDT, o,p'-DDE and p,p'-DDE whereas for organophosphate pesticides, they were chlorpyrifos and diazinon. At the river upstream where a dam is located for public water supply, incidents of pesticide levels exceeding the European Economic Community Directive of water quality standards have occurred. Furthermore, the wetland ecosystems located at the downstream of the river which houses the fireflies community is being threatened by occasional pesticide levels above EPA limits for freshwater aquatic organisms. The occurrence of these residual pesticides in the Selangor River can be attributed to the intense agriculture and urban activity.
  18. Wong C, Tan LT, Mujahid A, Lihan S, Wee JLS, Ting LF, et al.
    Lett Appl Microbiol, 2018 Oct;67(4):384-391.
    PMID: 29998586 DOI: 10.1111/lam.13049
    Copper (Cu) tolerance was observed by endophytic fungi isolated from the carnivorous plant Nepenthes ampullaria (collected at an anthropogenically affected site, Kuching city; and a pristine site; Heart of Borneo). The fungal isolates, capable of tolerating Cu up to 1000 ppm (11 isolates in total), were identified through molecular method [internal transcribed spacer 4+5 (ITS4+5); ITS1+NL4; β-tubulin region using Bt2a + Bt2b], and all of them grouped with Diaporthe, Nigrospora, and Xylaria. A Cu biosorption study was then carried out using live and dead biomass of the 11 fungal isolates. The highest biosorption capacity of using live biomass was achieved by fungal isolates Xylaria sp. NA40 (73·26 ± 1·61 mg Cu per g biomass) and Diaporthe sp. NA41 (72·65 ± 2·23 mg Cu per g biomass), NA27 (59·81 ± 1·15 mg Cu per g biomass) and NA28 (56·85 ± 4·23 mg Cu per g biomass). The fungal isolate Diaporthe sp. NA41 also achieved the highest biosorption capacity of 59·33 ± 0·15 mg g-1 using dead biomass. The living biomass possessed a better biosorption capacity than the dead biomass (P 
  19. Yusop Z, Tan LW, Ujang Z, Mohamed M, Nasir KA
    Water Sci Technol, 2005;52(9):125-32.
    PMID: 16445181
    Runoff quality draining from 17.14 km2 urban catchment in Johor Bahru, Malaysia, was analysed. The land-use consists of residential (30.3%), agricultural (27.3%), open space (27.9%), industrial (8.1%) and commercial (6.4%) areas. Three storm events were sampled in detail. These storms produced stormflow between 0.84 mm and 27.82 mm, and peakflow from 2.19 m3/s to 42.36 m3/s. Water quality showed marked variation during storms especially for TSS, BOD and COD with maximum concentrations of 778 mg/l, 135 mg/l and 358 mg/l, respectively. Concentrations of TOC, DOC, NH3-N, Fe and level of colour were also high. In general, the river quality is badly polluted and falls in Class V based on the Malaysian Interim National Water Quality Standards. Event Mean Concentrations (EMC) for various parameters varied considerably between storms. The largest storm produced higher EMC for TSS, NO3-N and SS whereas the smaller storms tend to register higher EMC for BOD, COD, NH3-N, TOC, Ca, K, Mg, Fe and Zn. Such variations could be explained in terms of pollutant availability and the effects of flushing and dilution. Based on a three-month average recurrence interval (ARI) of rainfall, the estimated event loadings (ton/ha) of TSS, BOD, COD, TOC, NH3-N and NO3-N were 0.055, 0.016, 0.012, 0.039, 0.010, 0.0007 and 0.0002, respectively. Heavy metals present in trace quantities. Storms with 3 months ARI could capture about 70% of the total annual loads of major pollutants.
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