Displaying publications 41 - 60 of 60 in total

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  1. Pua KC, Khoo AS, Yap YY, Subramaniam SK, Ong CA, Gopala Krishnan G, et al.
    Med J Malaysia, 2008 Sep;63 Suppl C:59-62.
    PMID: 19230249
    Nasopharyngeal carcinoma (NPC) is a cancer which is common in Asia. We report the establishment and early results of a multi-institutional prospective study of nasopharyngeal carcinoma, which seeks to systematically collect data as well as blood and tumour tissue samples from patients diagnosed with nasopharyngeal cancer at six centres in Malaysia. A total of 484 confirmed NPC cases were reported from the six participating centres between 1st July 2007 and 29th February 2008. Of these, 225 were newly diagnosed cases, 53 were recurrent cases and 206 were in remission at the time of reporting. Amongst the newly diagnosed cases, the most common presenting symptom was the presence of neck lumps (42%). Ophthalmo-neurologic symptoms were the presenting symptoms of 11% of the new cases. The majority of cases (75%) presented at stage III/IV.
  2. Ong CK, Lim SL, Tan WC, Ong EE, Goh AS
    Med J Malaysia, 2008 Jun;63(2):109-12.
    PMID: 18942294 MyJurnal
    Frequent blood transfusions can lead to iron overload which may result in several endocrine complications especially in the absence of adequate chelation therapy. The objectives of this study are to determine the prevalence of endocrine complications in transfusion dependent thalassaemia patients and the correlation of endocrine complications with the degree of iron chelation. This retrospective study looked at cases of adult patients with transfusion dependent thalassaemia treated in the Haematology Unit, Penang Hospital. Of the 25 transfusion dependent thalassaemia patients, there were 10 male and 15 female patients respectively with almost equal number of Malay and Chinese patients (13 and 12 patients respectively). Short stature was seen in 36.0% of our patients. In our cohort, 12 patients had delayed puberty (male 70.0% and female 33.3%). Prevalence of osteoporosis was 36.0%. Hypogonadism was noted in 40.0% of males and 46.7% of females. 53.4% of the female population had menstrual abnormalities with prevalence of primary and secondary amenorrhoea at 26.7% each. The prevalence of other endocrinopathies was much lower: 8.0% had diabetes mellitus and only one patient had hypocortisolism. Iron chelation appeared insufficient in our study population. The high frequency of endocrine complications noted in our study supports the rationale for regular follow-up of transfusion dependent thalassaemic patients to ensure early detection and timely treatment of associated complications.
  3. Ong CW, Chan BT, Lim E, Abu Osman NA, Abed AA, Dokos S, et al.
    PMID: 23367368 DOI: 10.1109/EMBC.2012.6347433
    For patient's receiving mechanical circulatory support, malfunction of the left ventricular assist device (LVADs) as well as mal-positioning of the cannula imposes serious threats to their life. It is therefore important to characterize the flow pattern and pressure distribution within the ventricle in the presence of an LVAD. In this paper, we present a 2D axisymmetric fluid structure interaction model of the passive left ventricle (LV) incorporating an LVAD cannula to simulate the effect of the LVAD cannula placement on the vortex dynamics. Results showed that larger recirculation area was formed at the cannula tip with increasing cannula insertion depth, and this is believed to reduce the risk of thrombus formation. Furthermore, we also simulated suction events (collapse of the LV) by closing the inlet. Vortex patterns were significantly altered under this condition, and the greatest LV wall displacement was observed at the part of the myocardium closest to the cannula tip.
  4. Chan BT, Ong CW, Lim E, Abu Osman NA, Al Abed A, Lovell NH, et al.
    PMID: 23367367 DOI: 10.1109/EMBC.2012.6347432
    Dilated cardiomyopathy (DCM) is a common cardiac disease which leads to the deterioration in cardiac performance. A computational fluid dynamics (CFD) approach can be used to enhance our understanding of the disease, by providing us with a detailed map of the intraventricular flow and pressure distributions. In the present work, effect of ventricular size on the intraventricular flow dynamics and intraventricular pressure gradients (IVPGs) was studied using two different implementation methods, i.e. the geometry-prescribed and the fluid structure interaction (FSI) methods. Results showed that vortex strength and IVPGs are significantly reduced in a dilated heart, leading to an increased risk of thrombus formation and impaired ventricular filling. We suggest FSI method as the ultimate method in studying ventricular dysfunction as it provides additional cardiac disease prognostic factors and more realistic model implementation.
  5. Marmey P, Bothner B, Jacquot E, de Kochko A, Ong CA, Yot P, et al.
    Virology, 1999 Jan 20;253(2):319-26.
    PMID: 9918890
    Rice tungro bacilliform virus (RTBV) is a plant pararetrovirus and a member of the Caulimoviridae family and closely related to viruses in the Badnavirus genus. The coat protein of RTBV is part of the large polyprotein encoded by open reading frame 3 (ORF3). ORF3 of an RTBV isolate from Malaysia was sequenced (accession no. AF076470) and compared with published sequences for the region that encodes the coat protein or proteins. Molecular mass of virion proteins was determined by mass spectrometry (matrix-assisted laser desorption/ionization-TOF) performed on purified virus particles from three RTBV isolates from Malaysia. The N- and C-terminal amino acid sequences of the coat protein were deduced from the mass spectral analysis, leading to the conclusion that purified virions contain a single coat protein of 37 kDa. The location of the coat protein domain in ORF3 was reinforced as a result of immunodetection reactions using antibodies raised against six different segments of ORF3 using Western immunoblots after SDS-PAGE and isoelectrofocusing of proteins purified from RTBV particles. These studies demonstrate that RTBV coat protein is released from the polyprotein as a single coat protein of 37 kDa.
  6. Shahedah KK, How SH, Jamalludin AR, Mohd Faiz MT, Kuan YC, Ong CK
    Tuberc Respir Dis (Seoul), 2019 Jul;82(3):217-226.
    PMID: 30841021 DOI: 10.4046/trd.2018.0048
    BACKGROUND: Depression is a recognized complication of lung cancer underreported in developing countries such as Malaysia. Treating and identifying depression in cancer patients increases survival and quality of life. Our objectives are to study prevalence of depressive symptoms in newly diagnosed lung carcinoma, and examine the relationship of depressive symptoms with other influencing risk factors.

    METHODS: A 2-year, cross sectional study February 2015-February 2017, was conducted at Hospital Tengku Ampuan Afzan, and Penang General Hospital. One hundred and three patients with newly diagnosed, biopsy confirmed primary lung carcinoma were recruited. Self-rated patient's identification sheet, validated Center for Epidemiologic Studies Depression (CES-D), and Dukes University Religion Index score from three different main languages were used.

    RESULTS: Prevalence of current depressive symptoms (CES-D total score ≥16) is 37.9%. The result suggests prevalence of those at high risk of moderate to major depression, may need treatment. Multivariate analysis reveals those with good Eastern Cooperation Oncology Group factor (η2=0.24, p<0.001) married (η=0.14, p<0.001) with intrinsic religiosity (IR) (η=0.07, p<0.02) are more resistant to depression.

    CONCLUSION: One in three of lung carcinoma patients, are at increased risk for depression. Clinicians should be aware that risk is highest in those with poor performance status, single, and with poor IR. We suggest routine screening of depression symptoms as it is feasible, to be performed during a regular clinic visit with immediate referral to psychiatrist when indicated.

  7. Ong C, Tan RKJ, Le D, Tan A, Tyler A, Tan C, et al.
    BMC Public Health, 2021 05 22;21(1):971.
    PMID: 34022843 DOI: 10.1186/s12889-021-10992-6
    BACKGROUND: Gay, bisexual and queer (GBQ) men are frequently subjected to minority stressors that have negative impacts on their health. Milestones that include the acceptance and disclosure of sexual identity amongst GBQ men are hence key instruments in understanding the prevalence of internalised homophobia and predicting health outcomes. As such, this work takes a novel approach to deduce the correlates of delayed acceptance of sexual orientation in young GBQ men as a measure of internalised homophobia through retrospective self-reporting and age-based analysis.

    METHODS: Participants were recruited as part of a cohort study exploring the syndemic risks associated with HIV acquisition among young GBQ men in Singapore. We examined their levels of internalised, perceived, experienced homophobia, as well as their health behaviours and suicidal tendencies. Two separate variables were also self-reported by the participants - the age of questioning of sexual orientation and the age of acceptance of sexual orientation. We subsequently recoded a new variable, delayed acceptance of sexual orientation, by taking the difference between these two variables, regressing it as an independent and dependent variable to deduce its psychosocial correlates, as well as its association with other measured instruments of health.

    RESULTS: As a dependent variable, delayed acceptance of sexual orientation is positively associated with an increase of age and internalised homophobia, while being negatively associated with reporting as being gay, compared to being bisexual or queer. As an independent variable, delayed acceptance of sexual orientation was associated with a delayed age of coming out to siblings and parents, suicide ideation, historical use of substances including smoking tobacco cigarettes and consuming marijuana, as well as reporting higher levels of experienced, internalised and perceived homophobia.

    CONCLUSION: Greater levels of early intervention and efforts are required to reduce the heightened experience of minority stress resulting from communal and institutional hostilities. Areas of improvement may include community-based counselling and psychological support for GBQ men, while not forsaking greater education of the social and healthcare sectors. Most importantly, disrupting the stigma narrative of a GBQ 'lifestyle' is paramount in establishing an accepting social environment that reduces the health disparity faced by GBQ men.

  8. Suwinski P, Ong C, Ling MHT, Poh YM, Khan AM, Ong HS
    Front Genet, 2019;10:49.
    PMID: 30809243 DOI: 10.3389/fgene.2019.00049
    There is a growing attention toward personalized medicine. This is led by a fundamental shift from the 'one size fits all' paradigm for treatment of patients with conditions or predisposition to diseases, to one that embraces novel approaches, such as tailored target therapies, to achieve the best possible outcomes. Driven by these, several national and international genome projects have been initiated to reap the benefits of personalized medicine. Exome and targeted sequencing provide a balance between cost and benefit, in contrast to whole genome sequencing (WGS). Whole exome sequencing (WES) targets approximately 3% of the whole genome, which is the basis for protein-coding genes. Nonetheless, it has the characteristics of big data in large deployment. Herein, the application of WES and its relevance in advancing personalized medicine is reviewed. WES is mapped to Big Data "10 Vs" and the resulting challenges discussed. Application of existing biological databases and bioinformatics tools to address the bottleneck in data processing and analysis are presented, including the need for new generation big data analytics for the multi-omics challenges of personalized medicine. This includes the incorporation of artificial intelligence (AI) in the clinical utility landscape of genomic information, and future consideration to create a new frontier toward advancing the field of personalized medicine.
  9. Muthiah YD, Lee WL, Teh LK, Ong CE, Salleh MZ, Ismail R
    Clin Chim Acta, 2004 Nov;349(1-2):191-8.
    PMID: 15469873 DOI: 10.1016/j.cccn.2004.06.024
    BACKGROUND: Cytochrome P450 (CYP) 2C8 is a principle enzyme responsible for the metabolism of many clinically important drugs as well as endogenous compounds such as arachidonic acid. The enzyme is genetically polymorphic but a simple method is not available to study its genetic polymorphism. We developed and optimized a variant-specific PCR techniques to detect CYP2C8*2, CYP2C8*3 and CYP2C8*4.
    METHOD: Genomic DNA was extracted from blood using standard extraction methods. A two-step PCR method was developed to detect simultaneously three CYP2C8 variants. In the first PCR (PCR1), specific regions from exons 3, 5 and 8 of the CYP2C8 gene were amplified. The products were used as templates in parallel alleles-specific PCR (PCR2). This method was tested against DNA samples obtained from 57 healthy Malaysian volunteers.
    RESULT: The bands of interest were successfully amplified. This method showed specific and reproducible results when tested on healthy volunteers. DNA sequencing further confirmed genotype results obtained from current method.
    CONCLUSION: We have successfully developed and optimized a multiplex PCR method suitable for use in population studies of CYP2C8 polymorphism.
  10. Nalliah S, Chan SL, Ong CL, Suthan TH, Tan KC, She VN, et al.
    Singapore Med J, 2010 Apr;51(4):332-8.
    PMID: 20505913
    Internet search has been the main source for information and data mining in medical research. Its use by medical students has immensely contributed to learning activities. The main aim of the study was to determine the effectiveness of internet use by medical students during their initial years of clinical instruction in order to establish a diagnosis after being provided with the history and physical findings of a clinical problem.
  11. Ong C, Dokos S, Chan B, Lim E, Al Abed A, Bin Abu Osman NA, et al.
    PMID: 23680359 DOI: 10.1186/1742-4682-10-35
    Despite the rapid advancement of left ventricular assist devices (LVADs), adverse events leading to deaths have been frequently reported in patients implanted with LVADs, including bleeding, infection, thromboembolism, neurological dysfunction and hemolysis. Cannulation forms an important component with regards to thrombus formation in assisted patients by varying the intraventricular flow distribution in the left ventricle (LV). To investigate the correlation between LVAD cannula placement and potential for thrombus formation, detailed analysis of the intraventricular flow field was carried out in the present study using a two way fluid structure interaction (FSI), axisymmetric model of a passive LV incorporating an inflow cannula. Three different cannula placements were simulated, with device insertion near the LV apex, penetrating one-fourth and mid-way into the LV long axis. The risk of thrombus formation is assessed by analyzing the intraventricular vorticity distribution and its associated vortex intensity, amount of stagnation flow in the ventricle as well as the level of wall shear stress. Our results show that the one-fourth placement of the cannula into the LV achieves the best performance in reducing the risk of thrombus formation. Compared to cannula placement near the apex, higher vortex intensity is achieved at the one-fourth placement, thus increasing wash out of platelets at the ventricular wall. One-fourth LV penetration produced negligible stagnation flow region near the apical wall region, helping to reduce platelet deposition on the surface of the cannula and the ventricular wall.
  12. Ong CN, Phoon WO, Tan TC, Jeyaratnam J, Cho SC, Suma'mur PK, et al.
    Ann Acad Med Singap, 1984 Apr;13(2 Suppl):429-34.
    PMID: 6497348
    This study is based on a survey conducted in Hong Kong, Indonesia, Korea, Malaysia, the Philippines, Singapore, Sri Lanka and Thailand on occupational injuries during the years 1975-1980. The number of work accidents have risen rapidly during this period in all of the 8 countries studied. In the case of Thailand, the total number of work injuries increased four fold from 1975-1978, whereas, in Singapore it has almost doubled in 6 years. The number of permanent disablement nearly trebled in Korea, and the Philippines for the year 1967-1980. The largest percentage of accidents are lost-time injuries in all of the 8 countries. Thailand had a three fold increase in lost-time injuries whilst in Hong Kong the figure doubled. Six out of the 8 countries indicated that the building construction industry had the largest number of fatal accidents, followed by the manufacturing industry.
  13. Lee WS, Karthik SV, Ng RT, Ong SY, Ong C, Chiou FK, et al.
    Pediatr Neonatol, 2019 08;60(4):396-404.
    PMID: 31409456 DOI: 10.1016/j.pedneo.2018.09.007
    BACKGROUND: Current knowledge on the clinical features and natural history of childhood primary sclerosing cholangitis - inflammatory bowel disease in Asia is limited. We described the presenting features and natural history of primary sclerosing cholangitis-inflammatory bowel disease seen in a cohort of Southeast Asian children.

    METHODS: We conducted a retrospective review of childhood primary sclerosing cholangitis-inflammatory bowel disease from three tertiary centers in Singapore and Malaysia.

    RESULTS: Of 24 patients (boys, 58%; median age at diagnosis: 6.3 years) with primary sclerosing cholangitis-inflammatory bowel disease (ulcerative colitis, n = 21; Crohn's disease, n = 1; undifferentiated, n = 2), 63% (n = 15) were diagnosed during follow-up for colitis, and 21% (n = 5) presented with acute or chronic hepatitis, 17% (n = 4) presented simultaneously. Disease phenotype of liver involvement showed 79% had sclerosing cholangitis-autoimmune hepatitis overlap, 54% large duct disease, and 46% small duct disease. All patients received immunosuppression therapy. At final review after a median [±S.D.] duration follow-up of 4.7 [±3.8] years, 12.5% patients had normal liver enzymes, 75% persistent disease, and 12.5% liver failure. The proportion of patients with liver cirrhosis increased from 13% at diagnosis to 29%; 21% had portal hypertension, and 17% had liver dysfunction. One patient required liver transplant. Transplant-free survival was 95%. For colitis, 95% had pancolitis, 27% rectal sparing, and 11% backwash ileitis at initial presentation. At final review, 67% patients had quiescent bowel disease with immunosuppression. One patient who had UC with pancolitis which was diagnosed at 3 years old developed colorectal cancer at 22 years of age. All patients survived.

    CONCLUSIONS: Liver disease in primary sclerosing cholangitis-inflammatory bowel disease in Asian children has variable severity. With immunosuppression, two-thirds of patients have quiescent bowel disease but the majority have persistent cholangitis and progressive liver disease.

  14. Fazly ZA, Nurulaini R, Shafarin MS, Fariza NJ, Zawida Z, Muhamad HY, et al.
    Trop Biomed, 2013 Sep;30(3):535-42.
    PMID: 24189683 MyJurnal
    Four zoonotic parasites, Sarcocystis spp., Toxoplasma gondii, Trichinella spp. and Taenia spp were screened in exotic meats. A total of forty-six (n=46) meat samples from various species of exotic animals were received from all the 14 states in Malaysia from January 2012 to April 2012. All exotic meat samples were examined macroscopically and histologically for the four zoonotic parasites. Results by histological examination of exotic meats showed the presence of Sarcocystis and Toxoplasma cysts at 8.7% (n=4) and 4.3% (n=2) respectively. No Trichinella spp. and Taenia spp. were found.
  15. Lim WH, Ng CH, Tan DJH, Xiao J, Fu CE, Ong C, et al.
    Transplantation, 2024 Feb 01;108(2):473-482.
    PMID: 37439778 DOI: 10.1097/TP.0000000000004718
    BACKGROUND: Liver transplantation (LT) offers patients with decompensated cirrhosis the best chance at long-term survival. With the rising prevalence of diabetes, further clarity is needed on the impact of receiving a liver allograft from a donor with diabetes on post-LT outcomes. This study aims to evaluate the impact of donor diabetes on clinical outcomes after LT.

    METHODS: This is a retrospective analysis of the United Network for Organ Sharing registry data of LT recipients from January 1, 2000, to December 31, 2021. Outcomes analysis was performed using Cox proportional model for all-cause mortality and graft failure. Confounding was reduced by coarsened exact matching causal inference analysis.

    RESULTS: Of 66 960 donors identified, 7178 (10.7%) had diabetes. Trend analysis revealed a longitudinal increase in the prevalence of donor diabetes ( P  

  16. Lim WH, Tay P, Ng CH, Tan DJH, Ong C, Koh JH, et al.
    Aliment Pharmacol Ther, 2024 Mar;59(6):730-741.
    PMID: 38303565 DOI: 10.1111/apt.17888
    BACKGROUND: Although alcohol abstinence may be an effective intervention for alcohol-associated cirrhosis, its association with prognosis has not been systematically assessed or quantified.

    AIMS: To determine the prevalence of alcohol abstinence, factors associated with alcohol abstinence and the impact of abstinence on morbidity and overall survival in people with alcohol-associated cirrhosis.

    METHODS: We searched Medline and Embase from inception to 15 April 2023 for prospective and retrospective cohort studies describing alcohol abstinence in people with known alcohol-associated cirrhosis. Meta-analysis of proportions for pooled estimates was performed. The method of inverse variance, employing a random-effects model, was used to pool the hazard ratio (HR) comparing outcomes of abstinent against non-abstinent individuals with alcohol-associated cirrhosis.

    RESULTS: We included 19 studies involving 18,833 people with alcohol-associated cirrhosis. The prevalence of alcohol abstinence was 53.8% (CI: 44.6%-62.7%). Over a mean follow-up duration of 48.6 months, individuals who continued to consume alcohol had significantly lower overall survival compared to those who were abstinent (HR: 0.611, 95% CI: 0.506-0.738). These findings remained consistent in sensitivity/subgroup analysis for the presence of decompensation, study design and studies that assessed abstinence throughout follow-up. Alcohol abstinence was associated with a significantly lower risk of hepatic decompensation (HR: 0.612, 95% CI: 0.473-0.792).

    CONCLUSIONS: Alcohol abstinence is associated with substantial improvement in overall survival in alcohol-associated cirrhosis. However, only half of the individuals with known alcohol-associated cirrhosis are abstinent.

  17. Gwee KA, Lee WW, Ling KL, Ooi CJ, Quak SH, Dan YY, et al.
    J Gastroenterol Hepatol, 2018 Oct;33(10):1707-1716.
    PMID: 29697855 DOI: 10.1111/jgh.14268
    The concept of consuming microorganisms in the treatment of a medical condition and in health maintenance has gained much attraction, giving rise to an abundance of medical claims and of health supplements. This study identified relevant clinical questions on the therapeutic use of probiotics and reviewed the literature in irritable bowel syndrome, inflammatory bowel disease, impaired intestinal immunity, liver disease, intestinal infections, and common childhood digestive disorders. Statements were developed to address these clinical questions. A panel of experienced clinicians was tasked to critically evaluate and debate the available data. Both consensus and contentious statements are presented to provide to clinicians a perspective on the potential of probiotics and importantly their limitations.
  18. Kim WJ, Gupta V, Nishimura M, Makita H, Idolor L, Roa C, et al.
    Int J Tuberc Lung Dis, 2018 07 01;22(7):820-826.
    PMID: 29914609 DOI: 10.5588/ijtld.17.0524
    BACKGROUND: Chronic obstructive pulmonary disease (COPD) is a heterogeneous condition that can differ in its clinical manifestation, structural changes and response to treatment.

    OBJECTIVE: To identify subgroups of COPD with distinct phenotypes, evaluate the distribution of phenotypes in four related regions and calculate the 1-year change in lung function and quality of life according to subgroup.

    METHODS: Using clinical characteristics, we performed factor analysis and hierarchical cluster analysis in a cohort of 1676 COPD patients from 13 Asian cities. We compared the 1-year change in forced expiratory volume in one second (FEV1), modified Medical Research Council dyspnoea scale score, St George's Respiratory Questionnaire (SGRQ) score and exacerbations according to subgroup derived from cluster analysis.

    RESULTS: Factor analysis revealed that body mass index, Charlson comorbidity index, SGRQ total score and FEV1 were principal factors. Using these four factors, cluster analysis identified three distinct subgroups with differing disease severity and symptoms. Among the three subgroups, patients in subgroup 2 (severe disease and more symptoms) had the most frequent exacerbations, most rapid FEV1 decline and greatest decline in SGRQ total score.

    CONCLUSION: Three subgroups with differing severities and symptoms were identified in Asian COPD subjects.

  19. Nairismägi ML, Tan J, Lim JQ, Nagarajan S, Ng CC, Rajasegaran V, et al.
    Leukemia, 2016 06;30(6):1311-9.
    PMID: 26854024 DOI: 10.1038/leu.2016.13
    Epitheliotropic intestinal T-cell lymphoma (EITL, also known as type II enteropathy-associated T-cell lymphoma) is an aggressive intestinal disease with poor prognosis and its molecular alterations have not been comprehensively characterized. We aimed to identify actionable easy-to-screen alterations that would allow better diagnostics and/or treatment of this deadly disease. By performing whole-exome sequencing of four EITL tumor-normal pairs, followed by amplicon deep sequencing of 42 tumor samples, frequent alterations of the JAK-STAT and G-protein-coupled receptor (GPCR) signaling pathways were discovered in a large portion of samples. Specifically, STAT5B was mutated in a remarkable 63% of cases, JAK3 in 35% and GNAI2 in 24%, with the majority occurring at known activating hotspots in key functional domains. Moreover, STAT5B locus carried copy-neutral loss of heterozygosity resulting in the duplication of the mutant copy, suggesting the importance of mutant STAT5B dosage for the development of EITL. Dysregulation of the JAK-STAT and GPCR pathways was also supported by gene expression profiling and further verified in patient tumor samples. In vitro overexpression of GNAI2 mutants led to the upregulation of pERK1/2, a member of MEK-ERK pathway. Notably, inhibitors of both JAK-STAT and MEK-ERK pathways effectively reduced viability of patient-derived primary EITL cells, indicating potential therapeutic strategies for this neoplasm with no effective treatment currently available.
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