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A nationwide survey on the knowledge and attitudes of Malaysian optometry students on patients' visual experiences during cataract surgery

Tan CS, Chen AH, Au Eong KG

Ann Acad Med Singap, 2006 Feb;35(2):72-6.
PMID: 16565757

INTRODUCTION: During cataract surgery under regional (retrobulbar, peribulbar or sub- Tenon's) or topical anaesthesia, many patients experience a variety of visual sensations in their operated eye intraoperatively. Between 3% and 16.2% of patients are frightened by their intraoperative visual experiences, which may increase the risk of intraoperative complications and affect patients' satisfaction with the surgery. This study aims to determine optometry students' beliefs and knowledge of visual sensations experienced by patients during cataract surgery under regional and topical anaesthesia.
MATERIALS AND METHODS: A nationwide survey of all Malaysian optometry students using a standardised, self-administered questionnaire.
RESULTS: All 129 optometry students participated in the survey, giving a 100% response rate. Overall, 26.4% and 29.5% of the students believed that patients undergoing cataract surgery under regional and topical anaesthesia, respectively, may experience no light perception, while 78.3% and 72.9%, respectively, thought that patients would experience light perception. Many respondents also believed that patients might experience a variety of other visual sensations. Of all respondents, 70.5% and 74.4% of students believed that patients undergoing cataract surgery under regional and topical anaesthesia, respectively, may be frightened by their visual experience and 93.0% and 85.3%, respectively, felt that preoperative counselling might help to alleviate this fear.
CONCLUSION: Many optometry students are aware that patients might encounter a variety of visual sensations during cataract surgery under local anaesthesia. A high proportion of students believe that patients may experience fear as a result of the intraoperative visual sensations and felt that preoperative counselling would be helpful.
Singapore Human Mutation/Polymorphism Database: a country-specific database for mutations and polymorphisms in inherited disorders and candidate gene association studies

Tan EC, Loh M, Chuon D, Lim YP

Hum Mutat, 2006 Mar;27(3):232-5.
PMID: 16429432

There is a need for country/population-specific databases because the existence of population-specific mutations for single gene disorders is well documented, and there is also good evidence for ethnic differences in the frequencies of genetic variations involved in complex disorders. Thus the Singapore Human Mutation/Polymorphism Database (SHMPD) was created to provide clinicians and scientists access to a central genetic database for the Singapore population. The data catalogued in the database include mutations identified in Singapore for Mendelian diseases, and frequencies of polymorphisms that have been investigated in either healthy controls or samples associated with specific phenotypes. Data from journal articles identified by searches in PubMed and other online resources, and via personal communications with researchers were compiled and assembled into a single database. Genes are categorized alphabetically and are also searchable by name and disease. The information provided for each variant of the gene includes the protein encoded, phenotype association, gender, size, and ethnic origin of the sample, as well as the reported genotype and allele frequencies, and direct links to the corresponding abstracts on PubMed. Our database will facilitate molecular diagnosis of Mendelian disorders and improve study designs for complex traits. It will be useful not only for researchers in Singapore, but also for those in countries with similar ethnic backgrounds, such as China, Taiwan, Hong Kong, Indonesia, and Malaysia.
HLA variants rs9271366 and rs9275328 are associated with systemic lupus erythematosus susceptibility in Malays and Chinese

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
Fulltext Generalized epilepsy with febrile seizure plus (GEFS+) spectrum: Novel de novo mutation of SCN1A detected in a Malaysian patient

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).
Fulltext Coitus to expedite the onset of labour: a randomised trial

Omar NS, Tan PC, Sabir N, Yusop ES, Omar SZ

BJOG, 2013 Feb;120(3):338-45.
PMID: 23145957 DOI: 10.1111/1471-0528.12054

To evaluate the effect of suggesting coitus as a safe and effective means to expedite labour on pregnancy duration and requirement for labour induction.
Apoptosis in Blastocystis spp. is related to subtype

Dhurga DB, Suresh KG, Tan TC, Chandramathi S

Trans R Soc Trop Med Hyg, 2012 Dec;106(12):725-30.
PMID: 23141370 DOI: 10.1016/j.trstmh.2012.08.005

Previous studies have shown that apoptosis-like features are observed in Blastocystis spp., an intestinal protozoan parasite, when exposed to the cytotoxic drug metronidazole (MTZ). This study reports that among the four subtypes of Blastocystis spp. investigated for rate of apoptosis when treated with MTZ, subtype 3 showed the highest significant increase after 72h of in vitro culture when treated with MTZ at 0.1mg/ml (79%; p<0.01) and 0.0001mg/ml (89%; p<0.001). The close correlation between viable cells and apoptotic cells for both dosages implies that the pathogenic potential of these isolates has been enhanced when treated with MTZ. This suggests that there is a mechanism in Blastocystis spp. that actually regulates the apoptotic process to produce higher number of viable cells when treated. Apoptosis may not just be programmed cell death but instead a mechanism to increase the number of viable cells to ensure survival during stressed conditions. The findings of the present study have an important contribution to influence chemotherapeutic approaches when developing drugs against the emerging Blastocystis spp. infections.
Growth arrest and non-apoptotic programmed cell death associated with the up-regulation of c-myc mRNA expression in T-47D breast tumor cells following exposure to Epipremnum pinnatum (L.) Engl. hexane extract

Tan ML, Muhammad TS, Najimudin N, Sulaiman SF

J Ethnopharmacol, 2005 Jan 15;96(3):375-83.
PMID: 15619555

Epipremnum pinnatum (L.) Engl. hexane extract produced a significant growth inhibition against T-47D breast carcinoma cells and analysis of cell death mechanisms indicated that the extract elicited a non-apoptotic programmed cell death. T-47D cells exposed to the extract at EC(50) concentration (72 h) for 24 h failed to demonstrate typical DNA fragmentation associated with apoptosis, as carried out using a modified TUNEL assay. In addition, acute exposure to the extract produced an insignificant regulation of caspase-3 and p53 mRNA expression but increased in the c-myc mRNA expression. Ultrastructural analysis using transmission electron microscope demonstrated distinct vacuolated cells, which strongly indicated a Type II non-apoptotic cell death although the changes in chromatin were also detected. The presence of non-apoptotic programmed cell death was then reconfirmed with annexin-V and propidium iodide staining. These findings suggested that up-regulation of c-myc mRNA expression may have contributed to the growth arrest and Type II non-apoptotic programmed cell death in the Epipremnum pinnatum (L.) Engl. hexane extract-treated T-47D cells.
Higher frequency of p53 gene mutations in diffuse large B-cell lymphoma with MALT component

Tai YC, Tan JA, Peh SC

Pathol. Int., 2004 Nov;54(11):811-8.
PMID: 15533223

p53 gene mutation is not a frequent event in the tumorigenesis of lymphomas and the expression of p53 protein is independent of p53 gene mutations. The present study aimed to investigate mutations in the p53 gene in a series of extranodal B-cell lymphomas, and its association with p53 protein expression. A total of 52 cases were graded histologically into Grade 1, Grade 2 and Grade 3 tumors and p53 protein expression was detected using immunohistochemistry. Mutations in the p53 gene were analyzed using polymerase chain reaction single-strand conformation polymorphism (PCR-SSCP) and mobility shifts were confirmed by direct sequencing. The tumors comprised 26 (50%) Grade 1, 9 (17%) Grade 2 and 15 (29%) Grade 3. A high proportion of Grade 2 (25%) tumors expressed p53 protein (P = 0.051) and carried p53 gene mutation (33%) (P = 0.218). However, p53 protein expression was not associated with p53 gene mutations (P = 0.057). Transversion mutations (88%) were more frequently detected than transition mutations (12%). The present study revealed that p53 gene mutations and p53 protein expression occurred in higher frequencies in Grade 2 tumors, which may be of pathogenetic importance. The high frequency of transversion mutations may reflect the influence of an etiological agent in the tumorigenesis of mucosa-associated lymphoid tissue (MALT lymphoma).
Synthesis of nano-sized hydroxyapatite

Tan SA, Ahmad Fauzi MN, Luay BH, Radzali O

Med J Malaysia, 2004 May;59 Suppl B:162-3.
PMID: 15468868

In this work, nanometer HA crystals have been synthesized via wet chemical precipitation and characterized. This research studies how key synthesis parameters affect the size and phase purity of the produced HA. Characterization work was carried out using X-ray powder diffraction method and scanning electron microscopy for phase identification and particle sizing, respectively.
Unusual form of superficial spreading microinvasive squamous cell carcinoma of uterine cervix involving the endometrium of uterus

Tan GC, Isa MR, Ng SP, Jamil YM

J Obstet Gynaecol Res, 2004 Oct;30(5):363-7.
PMID: 15327449

Microinvasive squamous cell carcinoma of the uterine cervix is a recognized entity and is defined as carcinoma with invasion of less than 5 mm penetration of the stroma and seldom metastasized. Our patient was a 70-year-old, multiparous woman who had a microinvasive, cervical, squamous cell carcinoma. The tumor had spread superficially into the entire endometrial cavity up to the fundus, totally replacing the columnar epithelium. This is an extremely rare phenomenon, with fewer than 20 cases reported so far in the literature.
Assessment of the ribose-induced Maillard reaction as a means of gelatine powder identification and quality control

Tan TC, AlKarkhi AF, Easa AM

Food Chem, 2012 Oct 15;134(4):2430-6.
PMID: 23442706 DOI: 10.1016/j.foodchem.2012.04.049

The addition of ribose to bovine or porcine gelatine solutions followed by heating at 95 °C yielded brown solutions with different pH, colour (CIE L(*) and b(*)) and absorbance (A(420*) values. These differences were used for gelatine powder identification, differentiation and quality control. Differentiation analysis of the Maillard reaction parameters was conducted using cluster analysis (CA) and confidence intervals (CI). The potential use of the method as a quality control procedure was evaluated by using statistical process control (SPC). CA revealed that the two types of gelatine could be classified into two different groups. CI (95% confidence) revealed that the absorbance and colour values could be used as indicators for differentiation between the two types of gelatine because the intervals between the Maillard reaction parameters of the samples were far apart. The methodology demonstrated good reproducibility because it behaved predictably based on the X¯-S charts generated from the SPC charts.
Fulltext Oil palm phenolics confer neuroprotective effects involving cognitive and motor functions in mice

Leow SS, Sekaran SD, Tan Y, Sundram K, Sambanthamurthi R

Nutr Neurosci, 2013 Sep;16(5):207-17.
PMID: 23433062 DOI: 10.1179/1476830512Y.0000000047

Phenolics are important phytochemicals which have positive effects on chronic diseases, including neurodegenerative ailments. The oil palm (Elaeis guineensis) is a rich source of water-soluble phenolics. This study was carried out to discover the effects of administering oil palm phenolics (OPP) to mice, with the aim of identifying whether these compounds possess significant neuroprotective properties.
Impact of epilepsy on employment in Malaysia

Lim KS, Wo SW, Wong MH, Tan CT

Epilepsy Behav, 2013 Apr;27(1):130-4.
PMID: 23416283 DOI: 10.1016/j.yebeh.2012.12.034

Studies on the impact of epilepsy on employment have been extensively performed in European and some Asian countries but not in Southeast Asia such as Malaysia, a country with a robust economy, low unemployment rate, and minimal social security benefits for the unemployed. This study aims to determine the impact of epilepsy on employment in Malaysia.
Purification of long helical capsid of newcastle disease virus from Escherichia coli using anion exchange chromatography

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.
Microsatellite markers uncover cryptic species of Odontotermes (Termitoidae: Termitidae) from Peninsular Malaysia

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.
Fulltext Specific and straightforward molecular investigation of β-thalassemia mutations in the Malaysian Malays and Chinese using direct TaqMan genotyping assays

Kho SL, Chua KH, George E, Tan JA

Genet. Mol. Res., 2013;12(3):2409-15.
PMID: 23479149 DOI: 10.4238/2013.February.28.4

Beta-thalassemia is a life-threatening inherited blood disorder. Rapid characterization of β-globin gene mutations is necessary because of the high frequency of Malaysian β-thalassemia carriers. A combination real-time polymerase chain reaction genotyping assay using TaqMan probes was developed to confirm β-globin gene mutations. In this study, primers and probes were designed to specifically identify 8 common β-thalassemia mutations in the Malaysian Malay and Chinese ethnic groups using the Primer Express software. "Blind tests" using DNA samples from healthy individuals and β-thalassemia patients with different genotypes were performed to determine the specificity and sensitivity of this newly designed assay. Our results showed 100% sensitivity and specificity for this novel assay. In conclusion, the TaqMan genotyping assay is a straightforward assay that allows detection of β-globin gene mutations in less than 40 min. The simplicity and reproducibility of the TaqMan genotyping assay permit its use in laboratories as a rapid and cost-effective diagnostic tool for confirmation of common β-thalassemia mutations in Malaysia.
Fulltext Segregation and genetic linkage analyses of river catfish, Mystus nemurus, based on microsatellite markers

Hoh BP, Siraj SS, Tan SG, Yusoff K

Genet. Mol. Res., 2013;12(3):2578-93.
PMID: 23479146 DOI: 10.4238/2013.February.28.1

The river catfish Mystus nemurus is an important fresh water species for aquaculture in Malaysia. We report the first genetic linkage map of M. nemurus based on segregation analysis and a linkage map using newly developed microsatellite markers of M. nemurus. A total of 70 of the newly developed polymorphic DNA microsatellite markers were analyzed on pedigrees generated using a pseudo-testcross strategy from 2 mapping families. In the first mapping family, 100 offspring were produced from randomly selected dams of the same populations; dams of the second family were selected from 2 different populations, and this family had 50 offspring. Thirty-one of the 70 markers segregated according to the Mendelian segregation ratio. Linkage analysis revealed that 17 microsatellite markers belonging to 7 linkage groups were obtained at a logarithm of the odds score of 1.2 spanning 584 cM by the Kosambi mapping function, whereas the other 14 remained unlinked. The results from this study will act as primer to a more extensive genetic mapping study aimed towards identifying genetic loci involved in determining economically important traits.
Paraoxonase 1 status in keratoconus: a preliminary study of activity and polymorphism

Poh R, Tan JA, Deva JP, Poo D, Yong Y, Arjunan S

West Indian Med J, 2012 Sep;61(6):569-73.
PMID: 23441349

To determine the activity of paraoxonase 1 (PON1) in keratoconus in a Malaysian population in comparison with non-keratoconic subjects.
Fulltext High throughput molecular confirmation of β-thalassemia mutations using novel TaqMan probes

Kho SL, Chua KH, George E, Tan JA

Sensors (Basel), 2013;13(2):2506-14.
PMID: 23429513 DOI: 10.3390/s130202506

β-Thalassemia is a public health problem where 4.5% of Malaysians are β-thalassemia carriers. The genetic disorder is caused by defects in the β-globin gene complex which lead to reduced or complete absence of β-globin chain synthesis. Five TaqMan genotyping assays were designed and developed to detect the common β-thalassemia mutations in Malaysian Malays. The assays were evaluated with 219 "blinded" DNA samples and the results showed 100% sensitivity and specificity. The in-house designed TaqMan genotyping assays were found to be cost- and time-effective for characterization of β-thalassemia mutations in the Malaysian population.
Periodic lateralized epileptiform discharges (PLEDs) in cerebral lupus correlated with white-matter lesions in brain MRI and reduced cerebral blood flow in SPECT

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.

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