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  1. Chai HC, Phipps ME, Othman I, Tan LP, Chua KH
    Lupus, 2013 Feb;22(2):198-204.
    PMID: 23257407 DOI: 10.1177/0961203312470183
    BACKGROUND: Human leukocyte antigen (HLA) antigens and genes have long been reported associated with systemic lupus erythematosus (SLE) susceptibility in many populations. With the advance in technologies such as genome-wide association studies, many newly discovered SLE-associated single-nucleotide polymorphisms (SNPs) have been reported in recent years. These include HLA-DRB1/HLA-DQA1 rs9271366 and HLA-DQB1/HLA-DQA2 rs9275328. Our aim was to investigate these SNPs in a Malaysian SLE cohort.
    MATERIALS AND METHODS: SNPs rs9271366 and rs9275328 were screened across 790 Malaysian citizens from three ethnic groups (360 patients and 430 healthy volunteers) by Taqman SNP genotyping assays. Allele and genotyping frequencies, Hardy-Weinberg equilibrium, Fisher's exact test and odds ratio were calculated for each SNP and ethnic group. Linkage disequilibrium and interaction between the two SNPs were also evaluated.
    RESULTS: The minor allele G and its homozygous genotype GG of HLA-DRB1/HLA-DQA1 rs9271366 significantly increased the SLE susceptibility in Malaysian patients, including those of Malay and Chinese ethnicity (odds ratio (OR) > 1, p 
  2. Tan EH, Yusoff AA, Abdullah JM, Razak SA
    J Pediatr Neurosci, 2012 May;7(2):123-5.
    PMID: 23248692 DOI: 10.4103/1817-1745.102575
    In this report, we describe a 15-year-old Malaysian male patient with a de novo SCN1A mutation who experienced prolonged febrile seizures after his first seizure at 6 months of age. This boy had generalized tonic clonic seizure (GTCS) which occurred with and without fever. Sequencing analysis of voltage-gated sodium channel a1-subunit gene, SCN1A, confirmed a homozygous A to G change at nucleotide 5197 (c.5197A > G) in exon 26 resulting in amino acid substitution of asparagines to aspartate at codon 1733 of sodium channel. The mutation identified in this patient is located in the pore-forming loop of SCN1A and this case report suggests missense mutation in pore-forming loop causes generalized epilepsy with febrile seizure plus (GEFS+) with clinically more severe neurologic phenotype including intellectual disabilities (mental retardation and autism features) and neuropsychiatric disease (anxiety disorder).
  3. Ong HT, Ong LM, Tan TE, Chean KY
    Med J Malaysia, 2013 Apr;68(2):189-94.
    PMID: 23629578 MyJurnal
    The clycoxygenase (COX) enzyme forms locally active prostaglandins responsible for producing inflammation and pain. Classical non-steroidal anti-inflammatory drugs (NSAID) inhibit the COX-2 enzyme that produces inflammatory prostaglandins as well as the COX-1 enzyme that produces gastric mucosa protecting prostaglandins. By specifically inhibiting only the COX-2 enzyme, coxibs thus reduce pain but do not damage the gastric mucosa. However, COX-2 at the vascular endothelium produces antithrombotic prostaglandins, and so by inhibiting COX-2 enzyme, the coxibs promote thrombosis. Rofecoxib and valdecoxib have been withdrawn because of the adverse cardiovascular events they induce. Amongst presently available coxibs cardiovascular risk is highest with enterocoxib and lowest with celecoxib. NSAIDS also increase cardiovascular events, the risk is highest with diclofenac and lowest with naproxen. Paracetamol and corticosteroids induce hypertension, while steroids also adversely affect the heart from metabolic change as well as fluid retention. Aspirin is an anti-thrombotic agent because of its ability to inhibit the COX-1 enzyme that produces the pro-aggregatory thromboxane. However, it increases gastrointestinal bleeding, can promote fluid retention and is nephrotoxic, all of which may lead to adverse cardiovascular outcomes. Patients at especially high risk of cardiovascular events from analgesic use include the elderly, and those with heart failure, hypertension, rheumatoid arthritis, chronic renal disease, chronic obstructive airway disease and previous myocardial infarction, cerebrovascular disease or peripheral vascular disease. Adverse cardiovascular events can occur within a week of initiation of analgesic treatment.
  4. Sahathevan R, Wan Yahya WNN, Tan HJ, Mohd Ibrahim N
    Med J Malaysia, 2013 Apr;68(2):187-8.
    PMID: 23629577
  5. Tan XE, Neoh HM, Hussin S, Zin NM
    Asian Pac J Trop Biomed, 2013 Mar;3(3):224-8.
    PMID: 23620843 DOI: 10.1016/S2221-1691(13)60055-6
    OBJECTIVE: To genotypically characterize methicillin-resistant Staphylococcus aureus (MRSA) strains isolated from medical and surgical wards in Universiti Kebangsaan Malaysia Medical Centre (UKMMC) in 2009.

    METHODS: MRSA strains were collected and molecularly typed by pulsed-field gel electrophoresis (PFGE).

    RESULTS: PFGE typing on 180 MRSA isolated in UKMMC identified 5 pulsotypes (A-E) and 6 singletons, where pulsotypes B and C were suspected to be divergent clones originating from a single ancestor. This study also showed that most MRSA strains were isolated from swab (119 isolates), followed by blood (22 isolates), tracheal aspirate (11 isolates) and sputum (10 isolates). On the other hand, urine and bone isolates were less, which were 4 and 1 isolates, respectively. The distribution of different pulsotypes of MRSA among wards suggested that MRSA was communicated in surgical and medical wards in UKMMC, with pulsotype B MRSA as the dominant strain. Besides, it was found that most deceased patients were infected by pulsotype B MRSA, however, no particular pulsotype could be associated with patient age, underlying disease, or ward of admittance.

    CONCLUSIONS: Five pulsotypes of MRSA and 6 singletons were identified, with pulsotype B MRSA as the endemic strains circulating in these wards, which is useful in establishment of preventive measures against MRSA transmission.

  6. Yap CF, Tan WS, Sieo CC, Tey BT
    Biotechnol Prog, 2013 Mar-Apr;29(2):564-7.
    PMID: 23364925 DOI: 10.1002/btpr.1697
    NP(Δc375) is a truncated version of the nucleocapsid protein of Newcastle disease virus (NDV) which self-assembles into a long helical structure. A packed bed anion exchange chromatography (PB-AEC), SepFastTM Supor Q pre-packed column, was used to purify NP(Δc375) from clarified feedstock. This PB-AEC column adsorbed 76.2% of NP(Δc375) from the clarified feedstock. About 67.5% of the adsorbed NP(Δc375) was successfully eluted from the column by applying 50 mM Tris-HCl elution buffer supplemented with 0.5 M NaCl at pH 7. Thus, a recovery yield of 51.4% with a purity of 76.7% which corresponds to a purification factor of 6.5 was achieved in this PB-AEC operation. Electron microscopic analysis revealed that the helical structure of the NP(Δc375) purified by SepFast(TM) Supor Q pre-packed column was as long as 490 nm and 22-24 nm in diameter. The antigenicity of the purified NP(Δc375) was confirmed by enzyme-linked immunosorbent assay.
  7. Chan KW, Tan GH, Wong RC
    Sci Justice, 2013 Mar;53(1):73-80.
    PMID: 23380066 DOI: 10.1016/j.scijus.2012.08.004
    Sixteen trace elements found in 309 street heroin samples, piped water and contaminated water were determined using inductively coupled plasma-mass spectrometry. All the street heroin samples were found to contain high levels of sodium, a reflection of the use of sodium bicarbonate during heroin synthesis. Additionally, this element was also found to be one of the potential contaminants acquired from the piped water. Calcium could be derived from lime while iron, aluminum and zinc could have come from the metallic container used in the processing/cutting stage. The levels of these elements remained low in the heroin and it could be due to the dilution effects from the addition of adulterants. Statistical validation was performed with six links of related heroin samples using principal component analysis to find the best pretreatment for sample classification. It was obtained that normalization followed by fourth root showed promising results with 8% errors in the sample clustering. The technique was then applied to the case samples. Finally, the result suggested that the case samples could have originated from at least two major groups respectively showing unique elemental profiles at the street level.
  8. Cheng S, Lee CT, Wan MN, Tan SG
    Gene, 2013 Apr 15;518(2):412-8.
    PMID: 23328646 DOI: 10.1016/j.gene.2012.12.084
    Termites from the genus Odontotermes are known to contain numerous species complexes that are difficult to tell apart morphologically or with mitochondrial DNA sequences. We developed markers for one such cryptic species complex, that is, Odontotermes srinakarinensis sp. nov. from Maxwell Hill Forest Reserve (Perak, Malaysia), and characterised them using a sample of 41 termite workers from three voucher samples from the same area. We then genotyped 150 termite individuals from 23 voucher samples/colonies of this species complex from several sites in Peninsular Malaysia. We analysed their population by constructing dendograms from the proportion of shared-alleles between individuals and genetic distances between colonies; additionally, we examined the Bayesian clustering pattern of their genotype data. All methods of analysis indicated that there were two distinct clusters within our data set. After the morphologies of specimens from each cluster were reexamined, we were able to separate the two species morphologically and found that a single diagnostic character found on the mandibles of its soldiers could be used to separate the two species quite accurately. The additional species in the clade was identified as Odontotermes denticulatus after it was matched to type specimens at the NHM London and Cambridge Museum of Zoology.
  9. Tan BB, Chan CY, Saw LB, Kwan MK
    Indian J Orthop, 2012 Nov;46(6):710-3.
    PMID: 23325978 DOI: 10.4103/0019-5413.104235
    Unstable spine fractures commonly occur in the setting of a polytraumatized patient. The aim of management is to balance the need for early operative stabilization and prevent additional trauma due to the surgery. Recent published literature has demonstrated the benefits of early stabilization of an unstable spine fracture particularly in patients with higher injury severity score (ISS). We report two cases of polytrauma with unstable spine fractures stabilized with a minimally invasive percutaneous pedicle screw instrumentation system as a form of damage control surgery. The patients had good recovery from the polytrauma injuries. These two cases illustrate the role of minimally invasive stabilization, its limitations and technical pitfalls in the management of unstable spine fractures in the polytrauma setting as a form of damage control surgery.
  10. Tan PC, Soe MZ, Sulaiman S, Omar SZ
    Obstet Gynecol, 2013 Feb;121(2 Pt 1):253-259.
    PMID: 23344273 DOI: 10.1097/AOG.0b013e31827e7fd9
    OBJECTIVE: To compare immediate with delayed (4 hours) oxytocin infusion after amniotomy on vaginal delivery within 12 hours and patient satisfaction with the birth process.

    METHODS: Parous women with favorable cervixes after amniotomy for labor induction were randomized to immediate titrated oxytocin or placebo intravenous infusion in a double-blind noninferiority trial. After 4 hours, study infusions were stopped, the women were assessed, and open-label oxytocin was started if required. Maternal satisfaction with the birth process was assessed with a 10-point visual numerical rating scale (lower score, greater satisfaction).

    RESULTS: Vaginal delivery rates at 12 hours were 91 of 96 (94.8%) compared with 91 of 94 (96.8%) (relative risk 0.98, 95% confidence interval [CI] 0.92-1.04, P=.72), and maternal satisfaction on a visual numerical rating scale (median [interquartile range]) was 3 [3-4] compared with 3 [3-5], P=.36 for immediate compared with delayed arm, respectively). Cesarean delivery, maternal fever, postpartum hemorrhage, uterine hyperactivity, and adverse neonatal outcome rates were similar between arms. The immediate oxytocin arm had a shorter amniotomy-to-delivery interval of 5.3±3.1 compared with 6.9±2.9 hours (P

  11. Aye SM, Lim KS, Ramli NM, Tan CT
    Lupus, 2013 Apr;22(5):510-4.
    PMID: 23358870 DOI: 10.1177/0961203312474705
    This is a case report on an uncommon correlation between periodic lateralized epileptiform discharges (PLEDs) and white-matter lesions in cerebral lupus, and with a reduced cerebral blood flow (CBF) in single-photon emission computed tomography (SPECT). A 47-year-old woman with a long-term history of systemic lupus erythematosus (SLE) presented with a seizure followed by frontal lobe dysfunction clinically. An electroencephalogram (EEG) showed bilateral independent PLEDs in the frontal region. A magnetic resonance image of the brain showed white-matter changes in the frontal periventricular region. Cerebral angiogram did not reveal any evidence of vasculitis. A cerebral SPECT with tracer injected during the EEG showing PLEDs showed a reduction in CBF in the frontal regions. Clinical recovery was observed with intravenous immunoglobulin. This case shows that PLEDs can be seen with white-matter changes in SLE.
  12. Tan SJ, Lim KH, Subramaniam G, Kam TS
    Phytochemistry, 2013 Jan;85:194-202.
    PMID: 22995929 DOI: 10.1016/j.phytochem.2012.08.016
    Nine bisindole alkaloids, comprising four belonging to the macroline-sarpagine group, and five belonging to the macroline-pleiocarpamine group, were isolated from the stem-bark extracts of Alstonia angustifolia (Apocynacea). Their structures were established using NMR and MS analyses.
  13. Chan KW, Tan GH, Wong RC
    J Forensic Sci, 2013 Jan;58 Suppl 1:S199-207.
    PMID: 23013257 DOI: 10.1111/j.1556-4029.2012.02285.x
    Statistical validation is crucial for the clustering of unknown samples. This study aims to demonstrate how statistical techniques can be optimized using simulated heroin samples containing a range of analyte concentrations that are similar to those of the case samples. Eight simulated heroin distribution links consisting of 64 postcut samples were prepared by mixing one of two mixtures of paracetamol-caffeine-dextromethorphan at different proportions with eight precut samples. Analyte contents and compositional variation of the prepared samples were investigated. A number of data pretreatments were evaluated by associating the postcut samples with the corresponding precut samples using principal component analysis and discriminant analysis. Subsequently, combinations of seven linkage methods and five distance measures were explored using hierarchical cluster analysis. In this study, Ward-Manhattan showed better distinctions between unrelated links and was able to cluster all related samples in very close distance under the known links on a dendogram. A similar discriminative outcome was also achieved by 90 unknown case samples when clustered via Ward-Manhattan.
  14. Aziz HA, Peh KK, Tan YT
    J Sex Med, 2009 Mar;6(3):682-95.
    PMID: 19143913 DOI: 10.1111/j.1743-6109.2008.01157.x
    Khat (Catha edulis) is an evergreen tree/shrub that is thought to affect sexual motivation or libido. Its positive effect on sexual desire is more frequently observed in females than in males and occurs when khat is chewed. Thus, khat's effects on sexual behavior may depend on the release mode of its active constituent.
  15. Goh BS, Tan SP, Husain S, Rose IM, Saim L
    J Laryngol Otol, 2009 Oct;123(10):1184-7.
    PMID: 19192318 DOI: 10.1017/S0022215109004642
    We report an extremely rare case of metachronous inflammatory myofibroblastic tumour in the temporal bone.
  16. Ranganathan S, Hsu WL, Yang UC, Tan TW
    BMC Bioinformatics, 2008 Dec 12;9 Suppl 12(Suppl 12):S1.
    PMID: 19091008 DOI: 10.1186/1471-2105-9-S12-S1
    The 2008 annual conference of the Asia Pacific Bioinformatics Network (APBioNet), Asia's oldest bioinformatics organisation set up in 1998, was organized as the 7th International Conference on Bioinformatics (InCoB), jointly with the Bioinformatics and Systems Biology in Taiwan (BIT 2008) Conference, Oct. 20-23, 2008 at Taipei, Taiwan. Besides bringing together scientists from the field of bioinformatics in this region, InCoB is actively involving researchers from the area of systems biology, to facilitate greater synergy between these two groups. Marking the 10th Anniversary of APBioNet, this InCoB 2008 meeting followed on from a series of successful annual events in Bangkok (Thailand), Penang (Malaysia), Auckland (New Zealand), Busan (South Korea), New Delhi (India) and Hong Kong. Additionally, tutorials and the Workshop on Education in Bioinformatics and Computational Biology (WEBCB) immediately prior to the 20th Federation of Asian and Oceanian Biochemists and Molecular Biologists (FAOBMB) Taipei Conference provided ample opportunity for inducting mainstream biochemists and molecular biologists from the region into a greater level of awareness of the importance of bioinformatics in their craft. In this editorial, we provide a brief overview of the peer-reviewed manuscripts accepted for publication herein, grouped into thematic areas. As the regional research expertise in bioinformatics matures, the papers fall into thematic areas, illustrating the specific contributions made by APBioNet to global bioinformatics efforts.
  17. Shiran MS, Tan GC, Kenali MS, Sabariah AR, Pathmanathan R
    Malays J Pathol, 2008 Jun;30(1):63-5.
    PMID: 19108414 MyJurnal
    Rosai-Dorfman disease (RDD), also known as sinus histiocytosis with massive lymphadenopathy (SHML), is a systemic disease involving nodal and extranodal tissues. We report a 48-year-old female with recurrent nasal obstruction due to polypoidal masses involving the nasal sinuses, turbinates and septum bilaterally, and lumps in the right infra-orbital region and region of the right lacrimal sac. A 4 cm right upper neck mass was also noted, which was initially diagnosed as histiocytic lymphoma. Histopathology of the nasal and infraorbital lesions revealed fibro-inflammatory masses containing histiocytic cells with large vesicular nuclei and abundant foamy cytoplasm exhibiting emperipolesis and lymphophagocytosis, admixed with scattered plasma cells and lymphocytes. These histiocytes revealed immunohistochemical positivity for S-100 protein and CD68, but were negative for CDla. The findings supported a diagnosis of RDD. This report serves to remind pathologists and clinicians of the extranodal manifestations of RDD and its potential confusion with lymphomas.
  18. Hashim SE, Tan HK, Wan-Hazabbah WH, Ibrahim M
    Ann Acad Med Singap, 2008 Nov;37(11):940-6.
    PMID: 19082201
    INTRODUCTION: Refractive error remains one of the primary causes of visual impairment in children worldwide, and the prevalence of refractive error varies widely. The objective of this study was to determine the prevalence of refractive error and study the possible associated factors inducing refractive error among primary school children of Malay ethnicity in the suburban area of Kota Bharu, Kelantan, Malaysia.

    MATERIALS AND METHODS: A school-based cross-sectional study was performed from January to July 2006 by random selection on Standard 1 to Standard 6 students of 10 primary schools in the Kota Bharu district. Visual acuity assessment was measured using logMAR ETDRS chart. Positive predictive value of uncorrected visual acuity equal or worse than 20/40, was used as a cut-off point for further evaluation by automated refraction and retinoscopic refraction.

    RESULTS: A total of 840 students were enumerated but only 705 were examined. The prevalence of uncorrected visual impairment was seen in 54 (7.7%) children. The main cause of the uncorrected visual impairment was refractive error which contributed to 90.7% of the total, and with 7.0% prevalence for the studied population. Myopia is the most common type of refractive error among children aged 6 to 12 years with prevalence of 5.4%, followed by hyperopia at 1.0% and astigmatism at 0.6%. A significant positive correlation was noted between myopia development with increasing age (P <0.005), more hours spent on reading books (P <0.005) and background history of siblings with glasses (P <0.005) and whose parents are of higher educational level (P <0.005). Malays in suburban Kelantan (5.4%) have the lowest prevalence of myopia compared with Malays in the metropolitan cities of Kuala Lumpur (9.2%) and Singapore (22.1%).

    CONCLUSION: The ethnicity-specific prevalence rate of myopia was the lowest among Malays in Kota Bharu, followed by Kuala Lumpur, and is the highest among Singaporean Malays. Better socio-economic factors could have contributed to higher myopia rates in the cities, since the genetic background of these ethnic Malays are similar.

  19. Kam TS, Tan SJ, Ng SW, Komiyama K
    Org. Lett., 2008 Sep 4;10(17):3749-52.
    PMID: 18683934 DOI: 10.1021/ol801354s
    A cytotoxic bisindole alkaloid possessing an unprecedented structure in which two indole moieties are bridged by an aromatic spacer unit has been isolated from Alstonia angustifolia. The structure was established by analysis of the spectroscopic data and confirmed by X-ray diffraction analysis. A possible biogenetic pathway from pyrocatechuic acid and pleiocarpamine is presented.
  20. Aasim WR, Gan SH, Tan SC
    Biomed Chromatogr, 2008 Sep;22(9):1035-42.
    PMID: 18655218 DOI: 10.1002/bmc.1073
    A stereospecific gas chromatography-mass spectrometry analysis method for amphetamine-type stimulants in human urine was recently developed. For maximum efficiency, liquid-liquid extraction and chiral derivatization of the analytes using (R)-(-)-alpha-methoxy-alpha-(trifluoromethyl)phenylacetyl chloride were performed simultaneously. The effects of (1) use of saturated sodium chloride in 2.0 M sodium hydroxide, (2) extraction solvent volume, (3) percentage of triethylamine, (4) derivatization reagent volume, (5) sample mixing time, (6) incubation temperature and (7) incubation time on method sensitivity and variability were assessed using a two-level, eight-run Plackett-Burman design followed by a fold-over design. The use of saturated sodium chloride solution and the derivatization reagent volume were significant factors (ANOVA, p<0.01). The saturated sodium chloride solution decreased sensitivity whereas an increased volume of derivatization reagent increased sensitivity. Calibration curves for all analytes were linear between 5 and 500 microg/L, with correlation coefficients of >0.99. Detection limits were
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