Displaying publications 1 - 20 of 27 in total

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  1. 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.
  2. 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.
  3. 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.
  4. 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.
  5. 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.
  6. 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.
  7. 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.
  8. Yadav M, Nambiar S, Khoo SP, Yaacob HB
    Arch Oral Biol, 1997 Aug;42(8):559-67.
    PMID: 9347118
    The prevalence and cellular distribution of human herpesvirus 7 (HHV-7) in archival labial salivary glands was analysed for virus-specific DNA sequences by polymerase chain reaction (PCR) and in situ hybridization signals. In addition, the cellular expression of HHV-7-encoded protein was detected by immunohistochemical staining with a virus-specific monoclonal antibody. Eleven of 20 samples were positive for the HHV-7 DNA sequence by PCR. Eighteen of 20 tissues analysed by in situ hybridization showed signals in ductal, serous and mucous cells. Some nuclei of these cells and also the myoepithelial population were positive. In immunolocalization studies, all 20 salivary glands consistently showed HHV-7-expressed protein in the cytoplasm of ductal cuboidal and columnar cells. The protein was also found in the cytoplasm of mucous and serous acinar cells that were immunopositive for HHV-7. The observations are consistent with the suggestion that the labial salivary gland is a site for virus replication, potential persistence and a source of infective HHV-7 in saliva.
  9. Zain RB, Khoo SP, Yeo JF
    Singapore Dent J, 1995 Jul;20(1):8-10.
    PMID: 9582682
    A clinical analysis of 304 cases of pyogenic granuloma (excluding pregnancy tumour) were obtained from the clinical evaluations submitted by clinicians while sending specimens for biopsy. The average age of the patients with pyogenic granuloma was 28.9 years with a peak age incidence in the second decade. More female patients were affected and the lesions present mainly in the Chinese. The majority of the lesions were ulcerated and pedunculated. The lesions had a mean diameter of 10.8 mm with a mean lesion duration of 6.0 months. The gingiva was the prevalent site for these lesions with a greater number being located in the maxilla. The recurrence rate was found to be 14.1%.
  10. 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.
  11. 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.
  12. 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.
  13. 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.
  14. 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.
  15. 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.
  16. 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.

  17. Khoo SP, Lim WT, Rajasuriar R, Nasir NH, Gravitt P, Woo YL
    Cancer Prev Res (Phila), 2021 01;14(1):105-112.
    PMID: 32917643 DOI: 10.1158/1940-6207.CAPR-20-0280
    Vaginal self-sampling for human papillomavirus (HPV) testing can potentially increase cervical screening coverage. This study aimed to investigate the acceptability of vaginal self-sampling for HPV testing and factors that might influence a woman's preference for this as a cervical screening method. This was a cross-sectional study that recruited 725 women from the urban and suburban areas of Selangor, Malaysia. All study participants were instructed to self-collect vaginal sample using a dry flocked swab before responding to a detailed questionnaire documenting their experience and preference for self-sampling. Most of the study participants (>80%) perceived vaginal self-sampling as easy, convenient, not embarrassing, comfortable, and were confident in performing the test. This suggests high acceptability toward vaginal self-sampling for HPV testing. Of the 725 women, 83% preferred self-sampling HPV testing over healthcare personnel sampling HPV testing and Pap test. Women with higher household income and full-time employment status were more likely to prefer self-sampling. Those who had not undergone Pap test also expressed preference for self-sampling HPV testing. Convenience and women's confidence in performing a vaginal self-sampling for HPV testing were the independent key factors that influenced the preference for self-sampling method. Vaginal self-sampling for HPV testing is highly acceptable among Malaysian women. It is the preferred choice as a primary cervical screening method and serves as an alternative to healthcare-acquired sample for Pap test. PREVENTION RELEVANCE: Organized cervical cancer screening remains unachievable in many countries. Self-sampling HPV testing is an evidence-based method that can remove barriers to cervical screening. This is particularly important for developing countries in order to achieve the WHO global strategy to accelerate cervical cancer elimination.
  18. 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.
  19. 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.

  20. 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.
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