Displaying publications 1 - 20 of 24 in total

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  1. Chieng TH, Roslan AC, Chuah JA
    Med J Malaysia, 2010 Dec;65(4):286-90.
    PMID: 21901947
    Scoring systems such as POSSUM and P-POSSUM have been developed to help predict mortality and morbidity in patients. The ratio of observed-to-predicted (O/P ratio) mortality and morbidity has been used as a performance indicator to compare different procedures, clinicians or hospitals. The aim of this study was to assess the predictive value of POSSUM compared with P-POSSUM in patients undergoing laparotomy in Queen Elizabeth Hospital, Sabah.
  2. Mah JJ, Chuah JA, Hayati F
    ANZ J Surg, 2021 Nov;91(11):2536-2538.
    PMID: 33713534 DOI: 10.1111/ans.16750
  3. Leong BD, Chuah JA, Kumar VM, Yip CH
    Asian Pac J Cancer Prev, 2007 Oct-Dec;8(4):525-9.
    PMID: 18260722
    INTRODUCTION: Malaysian women have a 1 in 20 chance of developing breast cancer in their lifetime. Sabah, formerly known as North Borneo, is part of East Malaysia with a population of 3.39 million and more than 30 ethnic groups. We conducted a 2 year prospective epidemiological study to provide unreported data of breast cancer from this part of the world and to recognise which particular group of patients are more likely to present with advanced disease.

    METHODS: All newly diagnosed breast cancers seen at the Queen Elizabeth Hospital, Kota Kinabalu, from January 2005 to December 2006 were included in the study. Patient and tumour characteristics, including age, race, education, socioeconomic background, parity, practice of breast feeding, hormonal medication intake, menopausal status, family history, mode of presentation, histology, grade, stage of disease and hormonal receptors status were collected and analysed.

    RESULTS: A total of 186 patients were seen. The commonest age group was 40 to 49 years old (32.3%). Chinese was the commonest race (30.6%) followed by Kadazan-Dusun (24.2%). The commonest histology was invasive ductal carcinoma (88.4%). Stages at presentation were Stage 0- 4.8%, Stage I- 12.9%, Stage II- 30.1%, Stage III- 36.6% and Stage IV- 15.6%. The estrogen and progesterone receptor status was positive in 59.1% and 54.8% of cases, respectively. 73.7% of Chinese patients presented with early cancer compared to 36.4% of the other races. Patients who presented with advanced disease were also poor, non-educated and from rural areas. 20.4% of patients defaulted treatment; most of them opted for traditional alternatives.

    CONCLUSIONS: Sabahan women with breast cancer present late. Great efforts are needed to improve public awareness of breast cancer, especially among those who have higher risk of presenting with advanced disease.
  4. Leong BD, Ramu P, Kumar VM, Chuah JA
    Med J Malaysia, 2008 Jun;63(2):148-9.
    PMID: 18942304 MyJurnal
    Synchronous cancers are defined as malignant tumours that occur simultaneously, each of which must be distinct with no possibility of one being the metastasis of the other. A 65 year old gentleman presented to us with two month history of epigastric pain associated with anaemia, loss of appetite and weight. He has no history of malignancy in his family. Colonoscopy revealed tumours at transverse colon and caecum. Intra-operatively, tumours were sited at caecum, transverse colon and jejunum. Tumours were diagnosed as synchronous adenocarcinoma histopathologically with loss of expression of MLH1 and MSH2. From literature search, this is the first reported triple synchronous tumours of the caecum, transverse colon and jejunum. We believe that this gentleman developed triple synchronous tumour through the sporadic MSI pathway.
  5. Leong BDK, Ariffin AZ, Chuah JA, Voo SY
    Med J Malaysia, 2013;68(1):10-2.
    PMID: 23466759 MyJurnal
    INTRODUCTION: Peripheral arterial disease(PAD) and abdominal aortic aneurysm(AAA) are two important underdiagnosed vascular pathologies. As they share common risk factors with coronary arterial disease, we conducted a study to look at their prevalence among patients with acute coronary syndrome(ACS).
    MATERIALS AND METHODS: Patients with ACS admitted to Queen Elizabeth Hospital, Malaysia, from February 2009 till August 2009 were screened prospectively for PVD and AAA. Patients' data and clinical findings were gathered and analyzed. Measurements of ankle brachial index (ABI) and abdominal aortic diameter were performed by a single assessor. PAD was defined as ABI ≤ 0.9 or diabetic patients with signs and symptoms of PAD and absence of pedal pulses. AAA was defined as abdominal aortic diameter ≥ 3cm.
    RESULTS: 102 patients were recruited with mean age of 59.5 years old. Male: female ratio was 6:1. 40.2% of patients had NSTEMI; 45.1%, STEMI and 14.7%, unstable angina. Risk factors profile is as follows: hypertension- 68.6%, smoking- 56.9%, hypercholesterolemia- 52.9%, diabetes mellitus- 35.3% and history of stroke- 5.9%. Median ABI was 1.1 with lowest reading of 0.4. Mean abdominal aortic size was 2.0cm with largest diameter of 3.3cm. PAD was present in 24.5% of patients and AAA in 2.0%. 68.0% of patients with PAD were asymptomatic. Smoking and age more than 60 years were independent predictors for PAD among ACS patients.
    CONCLUSIONS: PAD is strongly correlated with CAD with old age and smoker as independent predictors. However, association between AAA and ACS could not be established.
    Study site: Queen Elizabeth Hospital, Kota Kinabalu, Sabah, Malaysia
  6. Wong YM, Masunaga H, Chuah JA, Sudesh K, Numata K
    Biomacromolecules, 2016 Oct 10;17(10):3375-3385.
    PMID: 27642764
    Amyloid fibers are classified as a new generation of tunable bionanomaterials that exhibit new functions related to their distinctive characteristics, such as their universality, tunability, and stiffness. Here, we introduce the catalytic residues of serine protease into a peptide catalyst (PC) via an enzyme-mimic approach. The rational design of a repeating pattern of polar and nonpolar amino acids favors the conversion of the peptides into amyloid-like fibrils via self-assembly. Distinct fibrous morphologies have been observed at different pH values and temperatures, which indicates that different fibril packing schemes can be designed; hence, fibrillar peptides can be used to generate efficient artificial catalysts for amidolytic activities at mild pH values. The results of atomic force microscopy, Raman spectroscopy, and wide-angle X-ray scattering analyses are used to discuss and compare the fibril structure of a fibrillar PC with its amidolytic activity. The pH of the fibrillation reaction crucially affects the pKa of the side chains of the catalytic triads and is important for stable fibril formation. Temperature is another important parameter that controls the self-assembly of peptides into highly stacked and laminated morphologies. The morphology and stability of fibrils are crucial and represent important factors for demonstrating the capability of the peptides to exert amidolytic activity. The observed amidolytic activity of PC4, one of the PCs, was validated using an inhibition assay, which revealed that PC4 can perform enzyme-like amidolytic catalysis. These results provide insights into the potential use of designed peptides in the generation of efficient artificial enzymes.
  7. Ang SL, Shaharuddin B, Chuah JA, Sudesh K
    Int J Biol Macromol, 2020 Feb 15;145:173-188.
    PMID: 31866541 DOI: 10.1016/j.ijbiomac.2019.12.149
    Polyhydroxyalkanoates (PHAs) are biodegradable polyesters produced by microorganisms, under unbalanced growth conditions, as a carbon storage compound. PHAs are composed of various monomers such as 3-hydroxybutyrate (3HB) and 3-hydroxyhexanoate (3HHx). Silk fibroin (SF) derived from Bombyx mori cocoons, is a widely studied protein polymer commonly used for biomaterial applications. In this study, non-woven electrospun films comprising a copolymer of 3HB and 3HHx [P(3HB-co-3HHx)], SF and their blends were prepared by electrospinning technique. The growth and osteogenic differentiation of human umbilical cord-derived mesenchymal stem cells (hUC-MSCs) were studied using different types of fabricated electrospun films. The differentiation study revealed that electrospun P(3HB-co-3HHx)/SF film supports the differentiation of hUC-MSCs into the osteogenic lineage, confirmed by histological analysis using Alizarin Red staining, energy dispersive X-ray (EDX) and quantitative real-time PCR analysis (qPCR). Electrospun P(3HB-co-3HHx)/SF film up-regulated the expression of osteogenic marker genes, alkaline phosphatase (ALP) and osteocalcin (OCN), by 1.6-fold and 2.8-fold respectively, after 21 days of osteogenic induction. In conclusion, proliferation and osteogenic differentiation of hUC-MSCs were enhanced through the blending of P(3HB-co-3HHx) and SF. The results from this study suggest that electrospun P(3HB-co-3HHx)/SF film is a promising biomaterial for bone tissue engineering.
  8. Pulingam T, Foroozandeh P, Chuah JA, Sudesh K
    Nanomaterials (Basel), 2022 Feb 08;12(3).
    PMID: 35159921 DOI: 10.3390/nano12030576
    Nanoparticles (NPs) have remarkable properties for delivering therapeutic drugs to the body's targeted cells. NPs have shown to be significantly more efficient as drug delivery carriers than micron-sized particles, which are quickly eliminated by the immune system. Biopolymer-based polymeric nanoparticles (PNPs) are colloidal systems composed of either natural or synthetic polymers and can be synthesized by the direct polymerization of monomers (e.g., emulsion polymerization, surfactant-free emulsion polymerization, mini-emulsion polymerization, micro-emulsion polymerization, and microbial polymerization) or by the dispersion of preformed polymers (e.g., nanoprecipitation, emulsification solvent evaporation, emulsification solvent diffusion, and salting-out). The desired characteristics of NPs and their target applications are determining factors in the choice of method used for their production. This review article aims to shed light on the different methods employed for the production of PNPs and to discuss the effect of experimental parameters on the physicochemical properties of PNPs. Thus, this review highlights specific properties of PNPs that can be tailored to be employed as drug carriers, especially in hospitals for point-of-care diagnostics for targeted therapies.
  9. Goh LP, Chong ET, Chua KH, Chuah JA, Lee PC
    Asian Pac J Cancer Prev, 2014;15(17):7377-81.
    PMID: 25227845
    CYP2E1 PstI polymorphism G-1259C (rs3813867) genotype distributions vary significantly among different populations and are associated with both diseases, like cancer, and adverse drug effects. To date, there have been limited genotype distributions and allele frequencies of this polymorphism reported in the three major indigenous ethnic groups (KadazanDusun, Bajau, and Rungus) in Sabah, also known as North Borneo. The aim of this study was to investigate the genotype distributions and allele frequencies of the CYP2E1 PstI polymorphism G-1259C in these three major indigenous peoples in Sabah. A total of 640 healthy individuals from the three dominant indigenous groups were recruited for this study. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) at G-1259C polymorphic site of CYP2E1 gene was performed using the Pst I restriction enzyme. Fragments were analyzed using agarose gel electrophoresis and confirmed by direct sequencing. Overall, the allele frequencies were 90.3% for c1 allele and 9.7% for c2 allele. The genotype frequencies for c1/c1, c1/c2 and c2/c2 were observed as 80.9%, 18.8%, and 0.3%, respectively. A highly statistical significant difference (p<0.001) was observed in the genotype distributions between indigenous groups in Sabah with all Asian and non-Asian populations. However, among these three indigenous groups, there was no statistical significant difference (p>0.001) in their genotype distributions. The three major indigenous ethnic groups in Sabah show unique genotype distributions when compared with other populations. This finding indicates the importance of establishing the genotype distributions of CYP2E1 PstI polymorphism in the indigenous populations.
  10. Chong ET, Lee CC, Chua KH, Chuah JA, Lee PC
    BMJ Open, 2014;4(1):e004109.
    PMID: 24394801 DOI: 10.1136/bmjopen-2013-004109
    Our study aimed to investigate the association of CYP2E1 C-1019T RsaI and T7678A DraI polymorphisms and factors such as age, gender and ethnicity to the risk of gastrointestinal cancer (GIC) in Malaysians.
  11. Yee LN, Chuah JA, Chong ML, Phang LY, Raha AR, Sudesh K, et al.
    Microbiol Res, 2012 Oct 12;167(9):550-7.
    PMID: 22281521 DOI: 10.1016/j.micres.2011.12.006
    In this study, PHA biosynthesis operon of Comamonas sp. EB172, an acid-tolerant strain, consisting of three genes encoding acetyl-CoA acetyltransferase (phaA(Co) gene, 1182 bp), acetoacetyl-CoA reductase (phaB(Co) gene, 738 bp) and PHA synthase, class I (phaC(Co) gene, 1694 bp) were identified. Sequence analysis of the phaA(Co), phaB(Co) and phaC(Co) genes revealed that they shared more than 85%, 89% and 69% identity, respectively, with orthologues from Delftia acidovorans SPH-1 and Acidovorax ebreus TPSY. The PHA biosynthesis genes (phaC(Co) and phaAB(Co)) were successfully cloned in a heterologous host, Escherichia coli JM109. E. coli JM109 transformants harbouring pGEM'-phaC(Co)AB(Re) and pGEM'-phaC(Re)AB(Co) were shown to be functionally active synthesising 33 wt.% and 17 wt.% of poly(3-hydroxybutyrate) [P(3HB)]. E. coli JM109 transformant harbouring the three genes from the acid-tolerant Comamonas sp. EB172 (phaCAB(Co)) under the control of native promoter from Cupriavidus necator, in vivo polymerised P(3HB) when fed with glucose and volatile mixed organic acids (acetic acid:propionic acid:n-butyric acid) in ration of 3:1:1, respectively. The E. coli JM109 transformant harbouring phaCAB(Co) could accumulate P(3HB) at 2g/L of propionic acid. P(3HB) contents of 40.9% and 43.6% were achieved by using 1% of glucose and mixed organic acids, respectively.
  12. Leong BD, Chan KW, Ramu P, Kumar VM, Chuah JA
    Med J Malaysia, 2011 Jun;66(2):146-7.
    PMID: 22106698 MyJurnal
    Gallbladder tuberculosis (GT) is an extremely rare condition. This is thought to be due to the protective property of bile against the infection. Clinical and radiological diagnosis of GT is difficult. We describe a case of GT who initially presented to us with jaundice, a right hypochondrial mass and computed tomographic findings suggestive of gallbladder empyema. Diagnosis was made from histopathological examination of the resected gallbladder which revealed epitheloid granulomas with caseating necrosis and presence of Langhan's giant cells. From a literature search and to the best of our knowledge, this is the first GT to be reported in South East Asia.
  13. Chong ET, Goh LP, See EU, Chuah JA, Chua KH, Lee PC
    Asian Pac J Cancer Prev, 2016;17(2):647-53.
    PMID: 26925658
    BACKGROUND: Breast cancer is the most common type of cancer affecting Malaysian women. Recent statistics revealed that the cumulative probability of breast cancer and related deaths in Malaysia is higher than in most of the countries of Southeast Asia. Single nucleotide polymorphisms (SNPs) in CYP2E1 (rs6413432 and rs3813867), STK15 (rs2273535 and rs1047972) and XRCC1 (rs1799782 and rs25487) have been associated with breast cancer risk in a meta-analysis but any link in Southeast Asia, including Malaysia, remained to be determined. Hence, we investigated the relationship between these SNPs and breast cancer risk among Malaysian women in the present case-control study.

    MATERIALS AND METHODS: Genomic DNA was isolated from peripheral blood of 71 breast cancer patients and 260 healthy controls and subjected to polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis.

    RESULTS: Our study showed that the c1/c2 genotype or subjects with at least one c2 allele in CYP2E1 rs3813867 SNP had significantly increased almost 1.8-fold higher breast cancer risk in Malaysian women overall. In addition, the variant Phe allele in STK15 rs2273535 SNP appeared to protect against breast cancer in Malaysian Chinese. No significance association was found between XRCC1 SNPs and breast cancer risk in the population.

    CONCLUSIONS: This study provides additional knowledge on CYP2E1, STK15 and XRCC1 SNP impact of risk of breast cancer, particularly in the Malaysian population. From our findings, we also recommend Malaysian women to perform breast cancer screening before 50 years of age.

  14. Sudesh K, Bhubalan K, Chuah JA, Kek YK, Kamilah H, Sridewi N, et al.
    Appl Microbiol Biotechnol, 2011 Mar;89(5):1373-86.
    PMID: 21279347 DOI: 10.1007/s00253-011-3098-5
    Polyhydroxyalkanoate (PHA) is a potential substitute for some petrochemical-based plastics. This biodegradable plastic is derived from microbial fermentation using various carbon substrates. Since carbon source has been identified as one of the major cost-absorbing factors in PHA production, cheap and renewable substrates are currently being investigated as substitutes for existing sugar-based feedstock. Plant oils have been found to result in high-yield PHA production. Malaysia, being the world's second largest producer of palm oil, is able to ensure continuous supply of palm oil products for sustainable PHA production. The biosynthesis and characterization of various types of PHA using palm oil products have been described in detail in this review. Besides, by-products and waste stream from palm oil industry have also demonstrated promising results as carbon sources for PHA biosynthesis. Some new applications in cosmetic and wastewater treatment show the diversity of PHA usage. With proper management practices and efficient milling processes, it may be possible to supply enough palm oil-based raw materials for human consumption and other biotechnological applications such as production of PHA in a sustainable manner.
  15. Subramaniam S, Johan S, Hayati F, Ng CY, Azizan N, Chuah JA, et al.
    BMC Surg, 2020 Jun 11;20(1):130.
    PMID: 32527309 DOI: 10.1186/s12893-020-00787-8
    BACKGROUND: Sialolipoma is a rare tumour which may arise from both major and minor salivary glands and has recently been described as a variant of salivary gland lipomatous lesions.

    CASE PRESENTATION: We report a 54-year-old male who presented with a 7-year history of large right anterior neck swelling. He was clinically euthyroid and had no compressive or infiltrative symptoms. He sought medical attention due to the discomfort exerted by the weight of the mass and was keen for excision. The swelling appeared like a goitre but physical examination proved otherwise. Imaging was suggestive of a benign tumour arising from the right parapharyngeal fossa. The mass was surgically excised and was noted to be adherent to part of the submandibular gland. Histopathological examination revealed a new variant of benign adipocytic tumour of salivary gland or sialolipoma arising from the submandibular gland. Besides being the largest sialolipoma to be reported, there are also no reports of giant submandibular sialolipomas masquerading as a huge goitre in appearance.

    CONCLUSION: Submandibular sialolipomas can present in really large sizes and appear as a giant goitre. It is important to differentiate between benign lipomas from liposarcomas and tailor the management accordingly. Surgical enucleation is the preferred choice of treatment for these benign tumours with low recurrence rates.

  16. Valan A, Najid F, Chandran P, Abd Rahim AB, Chuah JA, Roslani AC
    Asian Pac J Cancer Prev, 2021 Mar 01;22(3):749-755.
    PMID: 33773538 DOI: 10.31557/APJCP.2021.22.3.749
    BACKGROUND: Malaysia is an ethnically diverse nation, comprising Malay, Chinese, Indian and indigenous groups. However, epidemiological studies on colorectal cancer have mainly focused on the three main ethnic groups. There is evidence that the clinico-pathological characteristics of some cancers may differ in indigenous populations, namely that they occur earlier and behave more aggressively. We aimed to determine if there were similar differences in colorectal cancer, focusing on the indigenous populations of Sabah.

    METHODS: Histopathological reports of all patients diagnosed with colorectal carcinoma from January 2012 to December 2016 from public hospitals in Sabah were retrieved from the central computerized database of the Pathology Department of Queen Elizabeth Hospital in Kota Kinabalu, Sabah. Supplementary data was obtained from patients' case files from each hospital. Clinico-pathological data were analysed using the IBM SPSS Statistical Software Version 23 for Windows for descriptive statistics (mean, median, ASR, AR, relative risk) and inferential statistics (Chi square test).

    RESULTS: A total of 696 patients met the inclusion criteria. The median age for colorectal cancer in Sabah was 62 years (95% CI 60.3 to 62.3), with an age specific incidence rate of 21.4 per 100 000 population. The age specific incidence rate in the indigenous populations was 26.6 per 100 000, much lower than the Chinese, at 65.0 per 100 000. The risk of colorectal cancer occurring before the age of 50 was three times higher in the indigenous population compared to the Chinese. The tumours were mainly left-sided (56.5%), adenocarcinoma in histology (98.4%) and moderately differentiated (88.7%). Approximately 79.2% of patients received curative treatment.

    CONCLUSION: Indigenous populations in Sabah develop colorectal cancer at an earlier age, and present at more advanced stages. This has implications for screening and therapeutic strategic planning. 
    .

  17. Lim H, Chuah JA, Chek MF, Tan HT, Hakoshima T, Sudesh K
    Int J Biol Macromol, 2021 Sep 01;186:414-423.
    PMID: 34246679 DOI: 10.1016/j.ijbiomac.2021.07.041
    Polyhydroxyalkanoates (PHAs) are biopolyesters synthesized by microorganisms as intracellular energy reservoirs under stressful environmental conditions. PHA synthase (PhaC) is the key enzyme responsible for PHA biosynthesis, but the importance of its N- and C-terminal ends still remains elusive. Six plasmid constructs expressing truncation variants of Aquitalea sp. USM4 PhaC (PhaC1As) were generated and heterologously expressed in Cupriavidus necator PHB-4. Removal of the first six residues at the N-terminus enabled the modulation of PHA composition without altering the PHA content in cells. Meanwhile, deletion of 13 amino acids from the C-terminus greatly affected the catalytic activity of PhaC1As, retaining only 1.1-7.4% of the total activity. Truncation(s) at the N- and/or C-terminus of PhaC1As gradually diminished the incorporation of comonomer units, and revealed that the N-terminal region is essential for PhaC1As dimerization whereas the C-terminal region is required for stabilization. Notably, transmission electron microscopy analysis showed that PhaC modification affected the morphology of intracellular PHA granules, which until now is only known to be regulated by phasins. This study provided substantial evidence and highlighted the significance of both the N- and C-termini of PhaC1As in regulating intracellular granule morphology, activity, substrate specificity, dimerization and stability of the synthase.
  18. Leong BD, Chuah JA, Kumar VM, Rohamini S, Siti ZS, Yip CH
    Singapore Med J, 2009 Aug;50(8):772-6.
    PMID: 19710974
    Sabah, formerly known as North Borneo, is part of East Malaysia. 52.2 percent of patients with breast cancer in Sabah presented at advanced stages and up to 20.4 percent of patients defaulted proper treatment, opting for traditional therapy. We performed a two-year prospective study looking at the treatment trends of breast cancer in Sabah.
  19. Leong BD, Chuah JA, Kumar VM, Mazri MY, Zainal AA
    Singapore Med J, 2008 Nov;49(11):e300-2.
    PMID: 19037533
    True and pseudoaneurysms of the visceral arteries are uncommon. They represent 0.1-0.2 percent of all vascular aneurysms. Visceral artery aneurysms (VAAs) should be treated due to their propensity to rupture and associated high mortality. We describe a 58-year-old man with pseudoaneurysm of the inferior pancreaticoduodenal artery and who presented with post-motor vehicle accident abdominal pain and a pulsatile epigastic mass. Computed tomography (CT) showed a pseudoaneurysm of the visceral artery, and selective mesenteric angiography showed the aneurysm to be arising from the inferior pancreaticoduodenal artery. The aneurysm was successfully treated with endovascular coil embolisation. CT angiogram at one month post-procedure revealed persistent occlusion of the aneurysm. To the best of our knowledge, this is the first reported pseudoaneurysm of inferior pancreaticoduodenal artery secondary to blunt abdominal trauma from a motor vehicle accident and also the first reported VAA from Malaysia.
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