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HLA-A, -B, -C, -DRB1 and -DQB1 alleles and haplotypes in 194 Southeast Asia Chinese from Peninsular Malaysia

Too CL, Tan LK, Heselynn H, Nor-Shuhaila S, Eashwary M, Wahinuddin S, et al.

Hum Immunol, 2019 Nov;80(11):906-907.
PMID: 31558331 DOI: 10.1016/j.humimm.2019.09.005

A total of 194 Southeast Asia Chinese from Peninsular Malaysia were genotyped for HLA-A, -B, -C -DRB1, and -DQB1 loci using polymerase chain reaction sequence-specific oligonucleotide probe hybridization methods. In this report, the HLA-B, HLA-DRB1 and HLA-DQB1 were in Hardy-Weinberg proportions (HWEP) (p > 0.05). We observed significant deviation from HWEP in HLA-A (p 
Reliability and validity of the Malay version of Attitudes toward Lesbians and Gay Men (MVATL/MVATG): a study on a group of medical students in Malaysia

Ng CG, Tan LK, Gill JS, Koh OH, Jambunathan S, Pillai SK, et al.

Asia Pac Psychiatry, 2013 Apr;5 Suppl 1:118-22.
PMID: 23857847 DOI: 10.1111/appy.12056

INTRODUCTION: This study aims to examine the validity and reliability of the Malay version of Attitudes toward Lesbians and Gay Men (MVATL/MVATG) among a group of medical students in Malaysia.
METHODS: It is a cross-sectional study of 173 medical students in the Faculty of Medicine, University of Kuala Lumpur, Malaysia. The participants were given the MVATL/MVATG, Index of Attitudes toward Homosexuals (IATH), Homosexuality Attitude Scale (HAS) and the English version of Attitude toward Lesbians and Gay Men. Two weeks later, these students were given the MVATLG again.
RESULTS: Significant correlation was found between the individual scores of MVATL and MVATG with IATH and HAS in the results. The scale was able to differentiate Muslim and Non-Muslim subjects. The internal consistency (Cronbach's alpha) of both the MVATL and MVATG were good, at 0.76 and 0.82, respectively. The parallel form reliability (Pearson's correlation) of MVATL was 0.0.73 and 0.74 for MVATG. The test-retest reliability of MVATL/MVATG was good (Intraclass correlation coefficient, ICC = 0.67 for MVATL and 0.60 for MVATG).
DISCUSSION: The MVATLG demonstrated good psychometric properties in measuring attitudes toward homosexuality among a group of medical students in Malaysia and it could be used as a simple instrument on young educated Malaysian adults.
KEYWORDS: Malaysia; attitude; gay men; homosexuality; lesbians; validation
Fulltext Image file formats

Tan L

Biomed Imaging Interv J, 2006 Jan;2(1):e6.
PMID: 21614221 DOI: 10.2349/biij.2.1.e6
Apical hypertrophic cardiomyopathy

Chia BL, Tan LK

Am J Cardiol, 1984 May 01;53(9):1413.
PMID: 6538741
Monte Carlo-based patient internal dosimetry in fluoroscopy-guided interventional procedures: A review

Fum WKS, Wong JHD, Tan LK

Phys Med, 2021 Apr;84:228-240.
PMID: 33849785 DOI: 10.1016/j.ejmp.2021.03.004

PURPOSE: This systematic review aims to understand the dose estimation approaches and their major challenges. Specifically, we focused on state-of-the-art Monte Carlo (MC) methods in fluoroscopy-guided interventional procedures.
METHODS: All relevant studies were identified through keyword searches in electronic databases from inception until September 2020. The searched publications were reviewed, categorised and analysed based on their respective methodology.
RESULTS: Hundred and one publications were identified which utilised existing MC-based applications/programs or customised MC simulations. Two outstanding challenges were identified that contribute to uncertainties in the virtual simulation reconstruction. The first challenge involves the use of anatomical models to represent individuals. Currently, phantom libraries best balance the needs of clinical practicality with those of specificity. However, mismatches of anatomical variations including body size and organ shape can create significant discrepancies in dose estimations. The second challenge is that the exact positioning of the patient relative to the beam is generally unknown. Most dose prediction models assume the patient is located centrally on the examination couch, which can lead to significant errors.
CONCLUSION: The continuing rise of computing power suggests a near future where MC methods become practical for routine clinical dosimetry. Dynamic, deformable phantoms help to improve patient specificity, but at present are only limited to adjustment of gross body volume. Dynamic internal organ displacement or reshaping is likely the next logical frontier. Image-based alignment is probably the most promising solution to enable this, but it must be automated to be clinically practical.
Glaucoma severity affects diffusion tensor imaging (DTI) parameters of the optic nerve and optic radiation

Sidek S, Ramli N, Rahmat K, Ramli NM, Abdulrahman F, Tan LK

Eur J Radiol, 2014 Aug;83(8):1437-41.
PMID: 24908588 DOI: 10.1016/j.ejrad.2014.05.014

To evaluate whether MR diffusion tensor imaging (DTI) of the optic nerve and optic radiation in glaucoma patients provides parameters to discriminate between mild and severe glaucoma and to determine whether DTI derived indices correlate with retinal nerve fibre layer (RNFL) thickness.
Generation of fluoroscopy-alike radiographs as alternative datasets for deep learning in interventional radiology

Fum WKS, Md Shah MN, Raja Aman RRA, Abd Kadir KA, Wen DW, Leong S, et al.

Phys Eng Sci Med, 2023 Dec;46(4):1535-1552.
PMID: 37695509 DOI: 10.1007/s13246-023-01317-5

In fluoroscopy-guided interventions (FGIs), obtaining large quantities of labelled data for deep learning (DL) can be difficult. Synthetic labelled data can serve as an alternative, generated via pseudo 2D projections of CT volumetric data. However, contrasted vessels have low visibility in simple 2D projections of contrasted CT data. To overcome this, we propose an alternative method to generate fluoroscopy-like radiographs from contrasted head CT Angiography (CTA) volumetric data. The technique involves segmentation of brain tissue, bone, and contrasted vessels from CTA volumetric data, followed by an algorithm to adjust HU values, and finally, a standard ray-based projection is applied to generate the 2D image. The resulting synthetic images were compared to clinical fluoroscopy images for perceptual similarity and subject contrast measurements. Good perceptual similarity was demonstrated on vessel-enhanced synthetic images as compared to the clinical fluoroscopic images. Statistical tests of equivalence show that enhanced synthetic and clinical images have statistically equivalent mean subject contrast within 25% bounds. Furthermore, validation experiments confirmed that the proposed method for generating synthetic images improved the performance of DL models in certain regression tasks, such as localizing anatomical landmarks in clinical fluoroscopy images. Through enhanced pseudo 2D projection of CTA volume data, synthetic images with similar features to real clinical fluoroscopic images can be generated. The use of synthetic images as an alternative source for DL datasets represents a potential solution to the application of DL in FGIs procedures.
Fulltext Evaluation of a modified Cefsulodin-Irgasan-Novobiocin agar for isolation of Yersinia spp

Tan LK, Ooi PT, Carniel E, Thong KL

PLoS One, 2014;9(8):e106329.
PMID: 25170941 DOI: 10.1371/journal.pone.0106329

Y. enterocolitica and Y. pseudotuberculosis are important food borne pathogens. However, the presence of competitive microbiota makes the isolation of Y. enterocolitica and Y. pseudotuberculosis from naturally contaminated foods difficult. We attempted to evaluate the performance of a modified Cefsulodin-Irgasan-Novobiocin (CIN) agar in the differentiation of Y. enterocolitica from non-Yersinia species, particularly the natural intestinal microbiota. The modified CIN enabled the growth of Y. enterocolitica colonies with the same efficiency as CIN and Luria-Bertani agar. The detection limits of the modified CIN for Y. enterocolitica in culture medium (10 cfu/ml) and in artificially contaminated pork (10(4) cfu/ml) were also comparable to those of CIN. However, the modified CIN provided a better discrimination of Yersinia colonies from other bacteria exhibiting Yersinia-like colonies on CIN (H2S-producing Citrobacter freundii, C. braakii, Enterobacter cloacae, Aeromonas hydrophila, Providencia rettgeri, and Morganella morganii). The modified CIN exhibited a higher recovery rate of Y. enterocolitica from artificially prepared bacterial cultures and naturally contaminated samples compared with CIN. Our results thus demonstrated that the use of modified CIN may be a valuable means to increase the recovery rate of food borne Yersinia from natural samples, which are usually contaminated by multiple types of bacteria.
Fulltext Prevalence and characterization of verotoxigenic-Escherichia coli isolates from pigs in Malaysia

Ho WS, Tan LK, Ooi PT, Yeo CC, Thong KL

BMC Vet Res, 2013;9:109.
PMID: 23731465 DOI: 10.1186/1746-6148-9-109

Postweaning diarrhea caused by pathogenic Escherichia coli, in particular verotoxigenic E. coli (VTEC), has caused significant economic losses in the pig farming industry worldwide. However, there is limited information on VTEC in Malaysia. The objective of this study was to characterize pathogenic E. coli isolated from post-weaning piglets and growers with respect to their antibiograms, carriage of extended-spectrum beta-lactamases, pathotypes, production of hemolysins and fimbrial adhesins, serotypes, and genotypes.
Prevalence and characterization of multidrug-resistant and extended-spectrum beta-lactamase-producing Escherichia coli from pediatric wards of a Malaysian hospital

Ho WS, Balan G, Puthucheary S, Kong BH, Lim KT, Tan LK, et al.

Microb Drug Resist, 2012 Aug;18(4):408-16.
PMID: 22394084 DOI: 10.1089/mdr.2011.0222

The emergence of Escherichia coli resistant to extended-spectrum cephalosporins (ESCs) is of concern as ESC is often used to treat infections by Gram-negative bacteria. One-hundred and ten E. coli strains isolated in 2009-2010 from children warded in a Malaysian tertiary hospital were analyzed for their antibiograms, carriage of extended-spectrum beta-lactamase (ESBL) and AmpC genes, possible inclusion of the beta-lactamase genes on an integron platform, and their genetic relatedness. All E. coli strains were sensitive to carbapenems. About 46% of strains were multidrug resistant (MDR; i.e., resistant to ≥3 antibiotic classes) and almost half (45%) were nonsusceptible to ESCs. Among the MDR strains, high resistance rates were observed for ampicillin (98%), tetracycline (75%), and trimethoprim/sulfamethoxazole (73%). Out of 110 strains, bla(TEM-1) (49.1%), bla(CTX-M) (11.8%), and bla(CMY-2) (6.4%) were detected. Twenty-one strains were ESBL producers. CTX-M-15 was the predominant CTX-M variant found and this is the first report of a CTX-M-27-producing E. coli strain from Malaysia. Majority (3.1%) of the strains harbored class 1 integron-encoded integrases with a predominance of aadA and dfr genes within the integron variable region. No gene cassette encoding ESBL genes was found and integrons were not significantly associated with ESBL or non-ESBL producers. Possible clonal expansion was observed for few CTX-M-15-positive strains but the O25-ST131 E. coli clone known to harbor CTX-M-15 was not detected while CMY-2-positive strains were genetically diverse.
HLA-A, -B, -C, -DRB1 and -DQB1 alleles and haplotypes in 951 Southeast Asia Malays from Peninsular Malaysia

Tan LK, Mohd-Farid B, Salsabil S, Heselynn H, Wahinuddin S, Lau IS, et al.

Hum Immunol, 2016 Oct;77(10):818-819.
PMID: 27370684 DOI: 10.1016/j.humimm.2016.06.022

A total of 951 Southeast Asia Malays from Peninsular Malaysia were genotyped for HLA-A, -B, -C -DRB1, and -DQB1 loci using polymerase chain reaction sequence-specific oligonucleotide probe hybridization methods. In this report, there were significant deviation from Hardy-Weinberg proportions for the HLA-A (p<0.0001), -B (p<0.0001), -DRB1 (p<0.0001) and -DQB1 (p<0.01) loci. Minor deviations from HWEP were detected for HLA-C (p=0.01). This genotype data was available in Allele Frequencies Network Database (AFND) Gonzalez-Galarza et al. (2015).
HLA-A, -B, -C, -DRB1 and -DQB1 alleles and haplotypes in 271 Southeast Asia Indians from Peninsular Malaysia

Nurul-Aain AF, Tan LK, Heselynn H, Nor-Shuhaila S, Eashwary M, Wahinuddin S, et al.

Hum Immunol, 2020 Jun;81(6):263-264.
PMID: 32312605 DOI: 10.1016/j.humimm.2020.04.004

A total of 271 Southeast Asia Indians from Peninsular Malaysia were genotyped for HLA-A, -B, -C, -DRB1, and -DQB1 loci using polymerase chain reaction sequence-specific oligonucleotide probe hybridization methods. In this report, HLA-B and HLA-DQB1 was in Hardy-Weinberg proportions (HWEP) (p > 0.05). We observed significant deviation from the HWEP for HLA-A (p
Comparison of commercial atlas-based automatic segmentation software for prostate radiotherapy treatment planning

Hizam DA, Tan LK, Saad M, Muaadz A, Ung NM

Phys Eng Sci Med, 2024 Apr 22.
PMID: 38647633 DOI: 10.1007/s13246-024-01411-2

This study aims to assess the accuracy of automatic atlas-based contours for various key anatomical structures in prostate radiotherapy treatment planning. The evaluated structures include the bladder, rectum, prostate, seminal vesicles, femoral heads and penile bulb. CT images from 20 patients who underwent intensity-modulated radiotherapy were randomly chosen to create an atlas library. Atlas contours of the seven anatomical structures were generated using four software packages: ABAS, Eclipse, MIM, and RayStation. These contours were then compared to manual delineations performed by oncologists, which served as the ground truth. Evaluation metrics such as dice similarity coefficient (DSC), mean distance to agreement (MDA), and volume ratio (VR) were calculated to assess the accuracy of the contours. Additionally, the time taken by each software to generate the atlas contour was recorded. The mean DSC values for the bladder exhibited strong agreement (>0.8) with manual delineations for all software except for Eclipse and RayStation. Similarly, the femoral heads showed significant similarity between the atlas contours and ground truth across all software, with mean DSC values exceeding 0.9 and MDA values close to zero. On the other hand, the penile bulb displayed only moderate agreement with the ground truth, with mean DSC values ranging from 0.5 to 0.7 for all software. A similar trend was observed in the prostate atlas contours, except for MIM, which achieved a mean DSC of over 0.8. For the rectum, both ABAS and MIM atlases demonstrated strong agreement with the ground truth, resulting in mean DSC values of more than 0.8. Overall, MIM and ABAS outperformed Eclipse and RayStation in both DSC and MDA. These results indicate that the atlas-based segmentation employed in this study produces acceptable contours for the anatomical structures of interest in prostate radiotherapy treatment planning.
Improved diagnostic accuracy in differentiating malignant and benign lesions using single-voxel proton MRS of the breast at 3 T MRI

Suppiah S, Rahmat K, Mohd-Shah MN, Azlan CA, Tan LK, Aziz YF, et al.

Clin Radiol, 2013 Sep;68(9):e502-10.
PMID: 23706826 DOI: 10.1016/j.crad.2013.04.002

To investigate the diagnostic accuracy of single-voxel proton magnetic resonance spectroscopy (SV (1)H MRS) by quantifying total choline-containing compounds (tCho) in differentiating malignant from benign lesions, and subsequently, to analyse the relationship of tCho levels in malignant breast lesions with their histopathological subtypes.