Displaying publications 1 - 20 of 26 in total

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  1. Khoo SP, High AS, Awang MN
    Singapore Dent J, 1995 Jul;20(1):21-3.
    PMID: 9582685
    A case of unicystic ameloblastoma which recurred after 15 years showing unusual histological features is reported. The prominent pseudo-glandular features present are described. This case highlights the importance of extensive histological examination for more characteristic features of ameloblastoma to reach a correct diagnosis.
  2. Khoo SP, Yap AU, Chan YH, Bulgiba AM
    J Orofac Pain, 2008;22(2):131-8.
    PMID: 18548842
    To develop a Malay-language version of the Axis II Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) through a formal translation/back-translation process and to summarize available data about the psychometric properties of the translated scales.
  3. Bapat RA, Mak KK, Pichika MR, Pang JC, Lin SL, Khoo SP, et al.
    BMC Oral Health, 2024 Mar 25;24(1):382.
    PMID: 38528501 DOI: 10.1186/s12903-024-04069-0
    AIMS AND OBJECTIVES: To analyze anti-MMP mode of action of Quaternary Ammonium Silane (QAS, codenamed as k21) by binding onto specific MMP site using computational molecular simulation and Anti-Sortase A (SrtA) mode of action by binding onto specific site using computational molecular simulation.

    MATERIALS AND METHODS: In silico Molecular Dynamics (MD) was used to determine the interactions of K21 inside the pocket of the targeted protein (crystal structure of fibroblast collagenase-1 complexed to a diphenyl-ether sulphone based hydroxamic acid; PDB ID: 966C; Crystal structure of MMP-2 active site mutant in complex with APP-derived decapeptide inhibitor. MD simulations were accomplished with the Desmond package in Schrödinger Drug Discovery Suite. Blood samples (~ 0.5 mL) collected into K2EDTA were immediately transferred for further processing using the Litron MicroFlow® PLUS micronucleus analysis kit for mouse blood according to the manufacturer's instructions. Bacterial Reverse Mutation Test of K21 Molecule was performed to evaluate K21 and any possible metabolites for their potential to induce point mutations in amino acid-requiring strains of Escherichia coli (E. coli) (WP2 uvrA (tryptophan-deficient)).

    RESULTS: Molecular Simulation depicted that K21 has a specific pocket binding on various MMPs and SrtA surfaces producing a classical clouting effect. K21 did not induce micronuclei, which are the result of chromosomal damage or damage to the mitotic apparatus, in the peripheral blood reticulocytes of male and female CD-1 mice when administered by oral gavage up to the maximum recommended dose of 2000 mg/kg. The test item, K21, was not mutagenic to Salmonella typhimurium (S. typhimurium) strains TA98, TA100, TA1535 and TA1537 and E. coli strain WP2 uvrA in the absence and presence of metabolic activation when tested up to the limit of cytotoxicity or solubility under the conditions of the test.

    CONCLUSION: K21 could serve as a potent protease inhibitor maintaining the physical and biochemical properties of dental structures.

  4. Verusingam ND, Yeap SK, Ky H, Paterson IC, Khoo SP, Cheong SK, et al.
    PeerJ, 2017;5:e3174.
    PMID: 28417059 DOI: 10.7717/peerj.3174
    Although numbers of cancer cell lines have been shown to be successfully reprogrammed into induced pluripotent stem cells (iPSCs), reprogramming Oral Squamous Cell Carcinoma (OSCC) to pluripotency in relation to its cancer cell type and the expression pattern of pluripotent genes under later passage remain unexplored. In our study, we reprogrammed and characterised H103 and H376 oral squamous carcinoma cells using retroviral OSKM mediated method. Reprogrammed cells were characterized for their embryonic stem cells (ESCs) like morphology, pluripotent gene expression via quantitative real-time polymerase chain reaction (RT-qPCR), immunofluorescence staining, embryoid bodies (EB) formation and directed differentiation capacity. Reprogrammed H103 (Rep-H103) exhibited similar ESCs morphologies with flatten cells and clear borders on feeder layer. Reprogrammed H376 (Rep-H376) did not show ESCs morphologies but grow with a disorganized morphology. Critical pluripotency genes Oct4, Sox2 and Nanog were expressed higher in Rep-H103 against the parental counterpart from passage 5 to passage 10. As for Rep-H376, Nanog expression against its parental counterpart showed a significant decrease at passage 5 and although increased in passage 10, the level of expression was similar to the parental cells. Rep-H103 exhibited pluripotent signals (Oct4, Sox2, Nanog and Tra-1-60) and could form EB with the presence of three germ layers markers. Rep-H103 displayed differentiation capacity into adipocytes and osteocytes. The OSCC cell line H103 which was able to be reprogrammed into an iPSC like state showed high expression of Oct4, Sox2 and Nanog at late passage and may provide a potential iPSC model to study multi-stage oncogenesis in OSCC.
  5. Zwiri A, Al-Hatamleh MAI, W Ahmad WMA, Ahmed Asif J, Khoo SP, Husein A, et al.
    Diagnostics (Basel), 2020 May 15;10(5).
    PMID: 32429070 DOI: 10.3390/diagnostics10050303
    Numerous studies have been conducted in the previous years with an objective to determine the ideal biomarker or set of biomarkers in temporomandibular disorders (TMDs). It was recorded that tumour necrosis factor (TNF), interleukin 8 (IL-8), IL-6, and IL-1 were the most common biomarkers of TMDs. As of recently, although the research on TMDs biomarkers still aims to find more diagnostic agents, no recent study employs the biomarker as a targeting point of pharmacotherapy to suppress the inflammatory responses. This article represents an explicit review on the biomarkers of TMDs that have been discovered so far and provides possible future directions towards further research on these biomarkers. The potential implementation of the interactions of TNF with its receptor 2 (TNFR2) in the inflammatory process has been interpreted, and thus, this review presents a new hypothesis towards suppression of the inflammatory response using TNFR2-agonist. Subsequently, this hypothesis could be explored as a potential pain elimination approach in patients with TMDs.
  6. Tan SC, Matzen P, Khoo SP
    Value Health, 2014 Nov;17(7):A743.
    PMID: 27202681 DOI: 10.1016/j.jval.2014.08.153
    Objectives
    Economic evaluations of BIAsp have been published in the context of different countries. This study aimed to evaluate the financial impact from a perspective of patients treated by public providers of different adoption rates of Biphasic Insulin Aspart (BIAsp; NovoMix 30 FlexPen®) versus Biphasic Human Insulin (BHI; Mixtard Penfill®) in treating T2DM.
    Methods
    An Excel based 5-year budget impact model was built to estimate insulin treated patients by public providers using the local prevalence data. The published demographic, efficacy and adverse event data for ASEAN subgroup analyses of A1chieve study was applied. Both insulin acquisition costs and medical costs for major hypoglycaemia and other complications were applied with a 3% discount rate to the estimated corresponding incidence rates derived from the UKPDS equations. The projected adoption rates were based on the 2013 utilisation volume data. Other local specific considerations e.g. subsidized selling prices and co-payments were included in the analyses for an assumed size of eligible patients. Sensitivity analyses were conducted.
    Results
    The adoption rates of BIAsp were assumed to increase from 23.6% in 2013 to 30% or 36.5% in 2018 for base case and upside scenario, respectively. In comparison to base case scenario, increases in adoption rate of BIAsp were associated with a cumulative increase up to slightly greater than S$ 2.02M in insulin acquisition cost but a potential cumulative net saving up to approximately S$0.92M in overall total costs over 5 years, attributing to subsidized selling price of BIAsp assuming it is included standard drug list and its significantly lower major hypoglycaemia risk, respectively. Cost savings were predicted for other complications.
    Conclusions
    The wider adoption of BIAsp was predicted to result in net cost savings from patient perspective in Singapore. More cost saving would be estimated in analyses with reduced productivity loss from a societal perspective.
  7. Loh HS, Ling SY, Shanmuhasuntharam P, Zain R, Yeo JF, Khoo SP
    Aust Dent J, 1998 Jun;43(3):188-91.
    PMID: 9707784
    This survey was undertaken to study the clinical features of trigeminal neuralgia in an Asian population. Demographic data of 44 patients treated at the Dental Faculty of the National University of Singapore and at the University of Malaya were reviewed. The results of the survey were analysed and comparisons made with those of Caucasian patients as reported in other studies where there was a general similarity in the clinical findings. Trigeminal neuralgia presented predominantly in females. Right-sided involvement occurred at a greater frequency, and the peak age at onset was between the sixth and seventh decades of life. The only significant variant in the present sample was the greater involvement of the mandibular branch of the trigeminal nerve rather than the maxillary division. In addition, there was a much greater representation from Chinese patients over Malays as compared with their ratios in the general population.
  8. Yusof WZ, Khoo SP
    Singapore Dent J, 1988 Dec;13(1):39-40.
    PMID: 3155002
    Mucosal sensitivity to chlorhexidine mouthwash is a rare occurrence and very few cases have been reported in the literature. The authors report 2 cases of oral sensitivity to chlorhexidine and discuss the side-effects, possible causes of sensitivity and the management of the cases.
  9. Khoo SP
    Family Physician, 1994;6:2-5.
    Temporomandibular disorders are the commonest orofacila pain. Many of them present themselves to the primary care physician. A fundamental familiarity with this disorder is essential for proper diagnosis and management.
  10. Kong DC, Chew KY, Tan EL, Khoo SP
    Cancer Cell Int, 2014;14:65.
    PMID: 25866477 DOI: 10.1186/1475-2867-14-65
    Epiregulin (EPR) is a novel member of the epidermal growth factor (EGF) family. It has been shown to promote wound healing in oral epithelium, enhance proliferation of other epithelial tissues, and is involved in several epithelial-related malignancies such as colorectal, lung, and bladder carcinoma. More recently, EPR transcripts were found to be high in a study on archival oral squamous cell carcinoma (OSCC) specimens. This implies that EPR may be responsible for the progression of OSCC. The aim of this was to elucidate the effects of EPR on (i) cell morphological changes, (ii) cell proliferation and (iii) receptor expression of the H-series OSCC cell lines.
  11. Keong JY, Low LW, Chong JM, Ong YY, Pulikkotil SJ, Singh G, et al.
    Saudi Dent J, 2020 Mar;32(3):148-154.
    PMID: 32180672 DOI: 10.1016/j.sdentj.2019.08.001
    PURPOSE: Periodontal ligament stem cells (PDLSCs) have considerable potential for use as a means of achieving periodontal regeneration due to their noteworthy proliferative properties and secretory functions. In particular, PDLSCs secrete vascular endothelial growth factor (VEGF) which enhances angiogenesis and osteogenesis. The resulting repair and development of blood vessels and hard tissues which would occur in the presence of these cells could be central to an effective periodontal regeneration procedure.The bacterial biofilm of tooth surface related to the periodontium might provide either an inhibition or a stimulus to different factors involved in a regenerative process. Cell culture experiments have been investigated in vitro by adding lipopolysaccharide (LPS) to the culture medium but the effect of various concentration of LPS in these circumstances has not been investigated. Therefore, this study aimed to investigate the effect of LPS concentrations on proliferation of PDLSCs in vitro and on their secretion of VEGF.

    MATERIALS AND METHODS: PDLSCs were treated with 0, 5, 10 and 20 µg/mL of Escherichia coli LPS. At 48 and 96 h, total cell numbers of control and LPS treated PDLSCs were counted by haemocytometer under a microscope. The VEGF concentration in the conditioned media of the PDLSCs was measured by ELISA.

    RESULTS: Rate of cell proliferation of PDLSCs decreased significantly in all LPS treated groups at both 48 h and 96 h except for the group treated with 5 µg/mL of LPS at 48 h. At both 48 and 96 h, VEGF secretion from PDLSCs was reduced significantly at all three LPS concentrations. There was no statistically significant difference in cell proliferation and the amount of VEGF secretion of PDLSCs among the groups treated with different LPS concentrations. No statistically significant change was found in cell proliferation of LPS treated PDLSCs over time, whereas VEGF secretion of PDLSCs was found to have increased significantly with time despite the LPS treatment.

    CONCLUSIONS: LPS reduced cell proliferation and VEGF secretion of PDLSCs, suggesting that periodontal pathogens might reduce the capability of PDLSCs in periodontal regeneration. Yet, LPS treated PDLSCs remained viable and VEGF secretion increased significantly over time. Further research is needed to study the potential use of PDLSCs in periodontal regeneration and the relationship of biofilm LPS accumulations.

  12. Menke JM, Ahsan MS, Khoo SP
    Biomark Cancer, 2017;9:1179299X17732007.
    PMID: 29085239 DOI: 10.1177/1179299X17732007
    Signal detection and Bayesian inferential tools were applied to salivary biomarkers to improve screening accuracy and efficiency in detecting oral squamous cell carcinoma (OSCC). Potential cancer biomarkers are identified by significant differences in assay concentrations, receiver operating characteristic areas under the curve (AUCs), sensitivity, and specificity. However, the end goal is to report to individual patients their risk of having disease given positive or negative test results. Likelihood ratios (LRs) and Bayes factors (BFs) estimate evidential support and compile biomarker information to optimize screening accuracy. In total, 26 of 77 biomarkers were mentioned as having been tested at least twice in 137 studies and published in 16 summary papers through 2014. Studies represented 10 212 OSCC and 25 645 healthy patients. The measure of biomarker and panel information value was number of biomarkers needed to approximate 100% positive predictive value (PPV). As few as 5 biomarkers could achieve nearly 100% PPV for a disease prevalence of 0.2% when biomarkers were ordered from highest to lowest LR. When sequentially interpreting biomarker tests, high specificity was more important than test sensitivity in achieving rapid convergence toward a high PPV. Biomarkers ranked from highest to lowest LR were more informative and easier to interpret than AUC or Youden index. The proposed method should be applied to more recently published biomarker data to test its screening value.
  13. Maharajan MK, Rajiah K, Khoo SP, Chellappan DK, De Alwis R, Chui HC, et al.
    PLoS One, 2017;12(1):e0168863.
    PMID: 28060838 DOI: 10.1371/journal.pone.0168863
    OBJECTIVES: To evaluate the attitudes and readiness of students of healthcare professions towards interprofessional learning.

    METHODOLOGY: A cross-sectional study design was used. Two different scales were used to measure the readiness for and perception of interprofessional learning; these were the 'Readiness for Interprofessional Learning Scale' and the 'Interdisciplinary Education Perception Scale'. A convenience sampling method was employed. The sample was drawn from undergraduate students enrolled in years 1 to 5 of medical, dental, pharmacy and health sciences programme. Descriptive and inferential statistics were used to analyse the data.

    RESULTS: The overall response rate was 83%. The students mentioned that shared learning with other healthcare professional students will increase their ability to understand clinical problems. The students also mentioned that such shared learning will help them to communicate better with patients and other professionals. The students preferred to work with individuals from their own profession. Participants from medical, dental, pharmacy, and health sciences had a difference in opinion about 'negative professional identity', a domain of the Readiness for Interprofessional Learning Scale. Based on the different year of study of the students, 'team work and collaboration', 'negative professional identity' and 'roles and responsibility' were the Interdisciplinary Education Perception Scale domains where students had a difference in opinion.

    CONCLUSIONS: Attitudes and readiness towards interprofessional learning showed significant differences among students of various healthcare professions; these differences also depended on the students' year of study. Interprofessional learning should be incorporated in the curriculum of all healthcare professional programs, which may foster students to become competent healthcare providers and understand each profession's role.

  14. Khoo SP, Lee, K.W.
    Ann Dent, 1995;2(1):-.
    MyJurnal
    A study was carried out to investigate whether smoking had any effect on the Langerhans cells in the oral mucosa, which might throw light onto the mechanism of malignant transformation of some keratotic lesions in the oral cavity. Thirty-two cases of keratotic lesions from biopsy specimens of smokers and non-smokers were studied. Langerhans cells were identified by immuno cytochemical staining for 5100 proteins and their densities quantified. Smokers were associated with a significant reduction in the Langerhans cell population compared to non-smokers. The mean values of Langellans cell density in light smokers and heavy smokers were 2 2 2 28.64/mm and 33.421mm respectively compared to 66.51/mm in non- smokers. There was a dose-response relation between the number of cigarettes smoked daily and the effect on cell counts. These findings of a local immunological effect of smoking on oral epithelium may explain the means by which cigarette smoking contributes to the development of oral cancer.
  15. Khoo SP, Lian CB
    Ann Dent, 1995 Summer;54(1-2):53-5.
    PMID: 8572549
    Spindle-cell lipoma (SCL) of the oral cavity is very rare. There are only four such reported cases in the literature. A concise literature review of SCL and a case report of a SCL affecting the cheek and lip of a 23-year-old man is presented.
  16. Khoo SP, Shanmuhasuntharam P, Mahadzir WM, Tay KK, Latif A, Nair S
    Asia Pac J Public Health, 1998;10(1):49-51.
    PMID: 10050209 DOI: 10.1177/101053959801000111
    The delay in the diagnosis of oral cancer has been variously reported as being contributed by the clinicians, patients or both. The purpose of this study was to evaluate the referral pattern of 65 patients eventually diagnosed as having oral squamous cell carcinoma. The results showed that 50% of the patients delayed seeking professional help for more than 3 months after being aware of the lesion. The majority of the patients consulted medical practitioners as the first source of help. The mean clinicians' and patients' delay were 10.3 weeks and 28.9 weeks respectively. Dental practitioners showed a tendency to refer more advanced lesions compared to the medical practitioners. The findings raise the concern that lack of patients' awareness, misdiagnosis by clinicians and late detection by dental practitioners prevail thus calling for urgent measures towards early detection of the disease.
  17. Khoo SP, Ong ST
    Ann Dent, 1998;5(1):49-52.
    MyJurnal
    Odontogenic carcinomas of the jaws are subclassified into malignant ameloblastoma, ameloblastic carcinoma and primary intraosseous carcinoma arising from within the bone. These may arise from residual islands of epithelium derived from dental lamina or epithelial lining of dental cysts. Ameloblastic carcinoma is extremely rare. An aggressive case of ameloblastic carcinoma occumng in a 59-year-old Malay man is presented. Wide excision of the primary lesion with radical neck dissection was carried out. He developed lung metastasis 4 months post-operatively. Despite chemotherapy upon discovery of lung metastasis, he expired 7 months following the initial diagnosis.
  18. Khoo SP, Primasari A, Saub R
    J Oral Sci, 2001 Sep;43(3):151-7.
    PMID: 11732734
    There is presently no line of distinction between oral lichen planus and other oral lichenoid lesions. The aim of this study is to determine using histomorphometry, the differences between these lesions. Paraffin sections from 7 normal buccal epithelium, 19 oral lichen planus (LP), 14 oral lichenoid lesions (LL) and 7 discoid lupus erythematosus-like lesions (DLE-ll) were selected. The nuclear volume (V(N)) and cellular-volume (V(CELL)) of the epithelium were assessed using an image analyser. The V(N) and V(CELL), derived for both basal and spinal strata in LP and DLE-ll were 2.3 times more than that of normal tissues. There was a significant difference between LP and LL (P < 0.005) and between LL and DLE-ll (P < 0.001), but not between LP and DLE-ll. In conclusion, there appears to be a difference between LP, LL and DLE-ll and V(N) and V(CELL) may serve as potential discriminators between these groups of lesions.
  19. Woo YL, Khoo SP, Gravitt P, Hawkes D, Rajasuriar R, Saville M
    Curr Oncol, 2022 Oct 02;29(10):7379-7387.
    PMID: 36290856 DOI: 10.3390/curroncol29100579
    Program ROSE (removing obstacles to cervical screening) is a primary HPV-based cervical screening program that incorporates self-sampling and digital technology, ensuring that women are linked to care. It was developed based on the principles of design thinking in the context of Malaysia. The program illustrates the importance of collaborative partnerships and addressing the multi-faceted barriers from policy changes, and infrastructure readiness to the implementation of a radically new cervical screening program in communities. The paradigm shift in cervical cancer requires a monumental and concerted effort in educating both the healthcare providers and the general public. In this short review, we highlight how Pilot Project ROSE incorporated evidence-based tools that rapidly scaled up to Program ROSE. These ideas and solutions can be adapted and adopted by other countries. Notwithstanding the impact of COVID-19, it is incumbent on countries to pave the road towards the elimination of cervical cancer with pre-existing footpaths.
  20. Banavar SR, Rawal SY, Paterson IC, Singh G, Davamani F, Khoo SP, et al.
    Saudi Dent J, 2021 Nov;33(7):693-701.
    PMID: 34803321 DOI: 10.1016/j.sdentj.2020.04.007
    Mesenchymal stem cells (MSCs) are extensively used in tissue regenerative procedures. One source of MSCs is the periodontal ligament (PDL) of teeth. Isolation of MSCs from extracted teeth is reasonably simple, being less invasive and presenting fewer ethical concerns than does the harvesting of MSC's from other sites. The objectives of this study were to isolate and characterize the PDL stem cells (PDLSC) from healthy adults' extracted teeth and then to characterize them by comparing them with bone-marrow derived MSCs (BMMSC).

    Methods: The PDL tissue was scraped from the roots of freshly extracted teeth to enzymatically digest using collagenase. The cells were sub-cultured. Flow-cytometric analysis for the MSC surface-markers CD105, CD73, CD166, CD90, CD34, CD45 and HLA-DR was performed. To confirm the phenotype, total RNA was extracted to synthesize cDNA and which was then subjected to RT-PCR. The gene-expression for Oct4A, Sox2, NANOG and GAPDH was determined by gel-electrophoresis. To assess their multilineage potential, cells were cultured with osteogenic, chondrogenic and adipogenic medium and then stained by Alizarin-red, Alcian-blue and Oil-Red-O respectively. MSCs from the bone-marrow were processed similarly to serve as controls.

    Results: The cells isolated from extracted teeth expanded successfully. On flow-cytometric analysis, the cells were positive for CD73, CD90, CD105, CD166 and negative for CD34, CD45 and HLA-DR. The PDLSCs expressed Oct4A, Sox2, and NANOG mRNA with GAPDH expression. Cells cultured in the osteogenic, chondrogenic and adipogenic media stained positive for Alizarin-red, Alcian-blue and Oil- Red-O respectively. The surface marker expression and the trilineage differentiation characteristics were comparable to those of the BMMSCs.

    Conclusions: The periodontal ligament tissue of extracted teeth is a potential source of therapeutically useful MSCs. Harvesting them is not invasive and are a promising source of MSC as the PDLSCs showed characteristics similar to those of the highly regarded MSC's derived from bone-marrow.

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