Displaying publications 1 - 20 of 139 in total

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  1. Yip CH, Bhoo Pathy N, Teo SH
    Med. J. Malaysia, 2014 Aug;69 Suppl A:8-22.
    PMID: 25417947 MyJurnal
    Four hundred and nineteen articles related to breast cancer were found in a search through a database dedicated to indexing all original data relevant to medicine published in Malaysia between the years 2000-2013. One hundred and fifty four articles were selected and reviewed on the basis of clinical relevance and future research implications. Overall, Malaysian women have poor survival from breast cancer and it is estimated that half of the deaths due to breast cancer could be prevented. Five-year survival in Malaysia was low and varies among different institutions even within the same disease stage, suggesting an inequity of access to optimal treatment or a lack of compliance to optimal treatment. Malaysian women have poor knowledge of the risk factors, symptoms and methods for early detection of breast cancer, leading to late presentation. Moreover, Malaysian women experience cancer fatalism, belief in alternative medicine, and lack of autonomy in decision making resulting in delays in seeking or avoidance of evidence-based medicine. There are ethnic differences in estrogen receptor status, HER2 overexpression and incidence of triple negative breast cancer which warrant further investigation. Malay women present with larger tumours and at later stages, and even after adjustment for these and other prognostic factors (stage, pathology and treatment), Malay women have a poorer survival. Although the factors responsible for these ethnic differences have not been elucidated, it is thought that pharmacogenomics, lifestyle factors (such as weight-gain, diet and exercise), and psychosocial factors (such as acceptance of 2nd or 3rd line chemotherapy) may be responsible for the difference in survival. Notably, survivorship studies show self-management programmes and exercise improve quality of life, highlighting the need to evaluate the psychosocial impact of breast cancer on Malaysian women, and to design culturally-, religiously- and linguistically-appropriate psycho-education programmes to help women cope with the disease and improve their quality of life. Research done in the Caucasian populations may not necessarily apply to local settings and it is important to embark on local studies particularly prevention, screening, diagnostic, prognostic, therapeutic and psychosocial research.
  2. Teo Sh, Teh K, Azura L, Ng Y
    Malays Orthop J, 2011 Nov;5(3):32-4.
    PMID: 25279034 MyJurnal DOI: 10.5704/MOJ.1111.005
    Tuberculosis (TB), once a disease confined to undeveloped or developing nations is currently in resurgence due to pandemic human immunodeficiency virus infection and immigration from endemic areas. TB is also known as the 'great mimicker'. Extra-pulmonary tuberculosis affecting the knee is rare in all forms of TB (0.1-0.3%). Here, we report a case of isolated highly erosive TB knee in a previously fit Burmese migrant worker. He presented with after a history of fall into a drain. The patient also reported pain and swelling over his left knee for the previous three years. He had been treated for a bacterial infection of the knee in another hospital but defaulted due to financial constraints. Arthrotomy of the knee was performed including washout. Diagnosis of TB of the knee was made based on the synovial fluid and tissue culture. Treatment with antituberculosis drugs was then initiated.
  3. Islam A, Teo SH, Rahman MA, Taufiq-Yap YH
    PLoS ONE, 2015;10(12):e0144805.
    PMID: 26700479 DOI: 10.1371/journal.pone.0144805
    A solution-phase route has been considered as the most promising route to synthesize noble nanostructures. A majority of their synthesis approaches of calcium carbonate (CaCO3) are based on either using fungi or the CO2 bubbling methods. Here, we approached the preparation of nano-precipitated calcium carbonate single crystal from salmacis sphaeroides in the presence of zwitterionic or cationic biosurfactants without external source of CO2. The calcium carbonate crystals were rhombohedron structure and regularly shaped with side dimension ranging from 33-41 nm. The high degree of morphological control of CaCO3 nanocrystals suggested that surfactants are capable of strongly interacting with the CaCO3 surface and control the nucleation and growth direction of calcium carbonate nanocrystals. Finally, the mechanism of formation of nanocrystals in light of proposed routes was also discussed.
  4. Hassan N, Ho WK, Mariapun S, Teo SH
    BMC Public Health, 2015;15:548.
    PMID: 26065413 DOI: 10.1186/s12889-015-1892-1
    To date, because of limited budgets and lower incidence of breast cancer, the majority of Asian countries do not have population-based screening programmes, but instead offer opportunistic screening. However, there have been few studies which have assessed the motivators for women attending such programmes and the appropriateness of the programmes in terms of targeting women at risk.
  5. Zulkhernain NS, Teo SH, Patel V, Tan PJ
    Curr Cancer Drug Targets, 2014;14(8):764-73.
    PMID: 25348017 DOI: 10.2174/1568009614666141028121347
    Targeted therapy, the treatment of cancer based on an underlying genetic alteration, is rapidly gaining favor as the preferred therapeutic approach. To date, although natural products represent a rich resource of bio-diverse drug candidates, only a few have been identified to be effective as targeted cancer therapies largely due to the incompatibilities to current high-throughput screening methods. In this article, we review the utility of a zebrafish developmental screen for bioactive natural product-based compounds that target signaling pathways that are intimately shared with those in humans. Any bioactive compound perturbing signaling pathways identified from phenotypic developmental defects in zebrafish embryos provide an opportunity for developing targeted therapies for human cancers. This model provides a promising tool in the search for targeted cancer therapeutics from natural products.
  6. Lee HB, Ho AS, Teo SH
    Cancer Chemother. Pharmacol., 2006 Jul;58(1):91-8.
    PMID: 16211395
    Given that p53 is a tumor suppressor that plays a central role in the cellular response to DNA damage and that more than 50% of all cancers have mutated p53, the wider utility of photodynamic therapy (PDT) in the treatment of cancer will depend on an understanding of whether p53 status modulates response to PDT. In this study, we investigated the photosensitivity of isogenic cell lines that differ only in their p53 status to PDT using hypericin as the photosensitizer.
  7. Lee M, Mariapun S, Rajaram N, Teo SH, Yip CH
    BMC Public Health, 2017 01 28;17(1):127.
    PMID: 28129762 DOI: 10.1186/s12889-017-4015-3
    BACKGROUND: The incidence of breast cancer in Asia is increasing because of urbanization and lifestyle changes. In the developing countries in Asia, women present at late stages, and mortality is high. Mammographic screening is the only evidence-based screening modality that reduces breast cancer mortality. To date, only opportunistic screening is offered in the majority of Asian countries because of the lack of justification and funding. Nevertheless, there have been few reports on the effectiveness of such programmes. In this study, we describe the cancer detection rate and challenges experienced in an opportunistic mammographic screening programme in Malaysia.

    METHODS: From October 2011 to June 2015, 1,778 asymptomatic women, aged 40-74 years, underwent subsidised mammographic screening. All patients had a clinical breast examination before mammographic screening, and women with mammographic abnormalities were referred to a surgeon. The cancer detection rate and variables associated with a recommendation for adjunct ultrasonography were determined.

    RESULTS: The mean age for screening was 50.8 years and seven cancers (0.39%) were detected. The detection rate was 0.64% in women aged 50 years and above, and 0.12% in women below 50 years old. Adjunct ultrasonography was recommended in 30.7% of women, and was significantly associated with age, menopausal status, mammographic density and radiologist's experience. The main reasons cited for recommendation of an adjunct ultrasound was dense breasts and mammographic abnormalities.

    DISCUSSION: The cancer detection rate is similar to population-based screening mammography programmes in high-income Asian countries. Unlike population-based screening programmes in Caucasian populations where the adjunct ultrasonography rate is 2-4%, we report that 3 out of 10 women attending screening mammography were recommended for adjunct ultrasonography. This could be because Asian women attending screening are likely premenopausal and hence have denser breasts. Radiologists who reported more than 360 mammograms were more confident in reporting a mammogram as normal without adjunct ultrasonography compared to those who reported less than 180 mammograms.

    CONCLUSION: Our subsidised opportunistic mammographic screening programme is able to provide equivalent cancer detection rates but the high recall for adjunct ultrasonography would make screening less cost-effective.

  8. Thirthagiri E, Cheong LS, Yip CH, Teo SH
    Fam. Cancer, 2009;8(4):355-8.
    PMID: 19399639 DOI: 10.1007/s10689-009-9244-x
    A truncating mutation (1100delC) in the cell cycle checkpoint kinase-2 gene, CHEK2, has been identified as a risk factor for familial and sporadic breast cancer in some Northern and Western European populations. However, the prevalence of CHEK2*1100delC in breast cancer appears to be population dependent. We analysed the prevalence of CHEK2*1100delC in 668 breast cancer cases, of which 542 were invasive breast cancers, from a hospital-based cohort of breast cancer patients from Kuala Lumpur, Malaysia. The variant was not found in any patients in this cohort, suggesting that CHEK2*1100delC is rare in our population, and unlikely to contribute significantly to risk to breast cancer among the Malay, Chinese and Indian ethnic groups in Malaysia. This suggests that screening for this allele should not be routinely conducted in Malaysia.
  9. Lee SH, Lee OS, Teo SH, Lee YS
    Gait Posture, 2017 09;57:57-68.
    PMID: 28577508 DOI: 10.1016/j.gaitpost.2017.05.023
    We conducted a meta-analysis to analyze how high tibial osteotomy (HTO) changes gait and focused on the following questions: (1) How does HTO change basic gait variables? (2) How does HTO change the gait variables in the knee joint? Twelve articles were included in the final analysis. A total of 383 knees was evaluated. There were 237 open wedge (OW) and 143 closed wedge (CW) HTOs. There were 4 level II studies and 8 level III studies. All studies included gait analysis and compared pre- and postoperative values. One study compared CWHTO and unicompartmental knee arthroplasty (UKA), and another study compared CWHTO and OWHTO. Five studies compared gait variables with those of healthy controls. One study compared operated limb gait variables with those in the non-operated limb. Gait speed, stride length, knee adduction moment, and lateral thrust were major variables assessed in 2 or more studies. Walking speed increased and stride length was increased or similar after HTO compared to the preoperative value in basic gait variables. Knee adduction moment and lateral thrust were decreased after HTO compared to the preoperative knee joint gait variables. Change in co-contraction of the medial side muscle after surgery differed depending on the degree of frontal plane alignment. The relationship between change in knee adduction moment and change in mechanical axis angle was controversial. Based on our systematic review and meta-analysis, walking speed and stride length increased after HTO. Knee adduction moment and lateral thrust decreased after HTO compared to the preoperative values of gait variables in the knee joint.
  10. Song CV, Teo SH, Taib NA, Yip CH
    Ecancermedicalscience, 2018;12:863.
    PMID: 30174725 DOI: 10.3332/ecancer.2018.863
    Introduction: The presence of a deleterious mutation, most commonly a BRCA mutation, has a tremendous impact on the management of breast cancer. We review the surgical management of BRCA mutation carriers, and two other potentially high-risk mutations, TP53 and PALB2.

    Methodology: A search was done on PubMed, limited to reviews and the English language only. The search terms used were 'BRCA' or 'PALB2' or 'TP53' and 'surgery'. Fifteen articles were identified by searching and one article was obtained from other sources.

    Results: Breast-conserving surgery has equivalent survival, but may have an increased risk of local recurrence, compared to mastectomy among BRCA mutation carriers. Contralateral prophylactic mastectomy may not improve overall survival, despite reducing the risk of developing contralateral breast cancer. The use of preoperative genetic testing allows patients to have combined curative and prophylactic surgery. However, preoperative genetic testing may influence patients to make rash decisions. In healthy BRCA mutation carriers, bilateral prophylactic mastectomy is done to prevent breast cancer from occurring. Bilateral prophylactic mastectomy is highly effective in reducing the risk of breast cancer in healthy BRCA mutation-positive women and may have a survival benefit. Prophylactic oophorectomy reduces the risk of ovarian cancer, but may not have an effect on the risk of breast cancer. There is a lack of studies on surgery for non-BRCA mutations. TP53 and PALB2 are potentially high-risk mutations for breast cancer, which may justify the use of prophylactic surgery. Advice should be given on a case-by-case basis.

    Conclusion: A comprehensive approach is needed to provide optimum treatment for breast cancer patients with deleterious mutations.

  11. Mariapun S, Ho WK, Kang PC, Li J, Lindström S, Yip CH, et al.
    Cancer Epidemiol. Biomarkers Prev., 2016 Feb;25(2):327-33.
    PMID: 26677210 DOI: 10.1158/1055-9965.EPI-15-0746
    Mammographic density is an established risk factor for breast cancer and has a strong heritable component. Genome-wide association studies (GWAS) for mammographic density conducted in women of European descent have identified several genetic associations, but none of the studies have been tested in Asians. We sought to investigate whether these genetic loci, and loci associated with breast cancer risk and breast size, are associated with mammographic density in an Asian cohort.
  12. Mariapun S, Li J, Yip CH, Taib NA, Teo SH
    PLoS ONE, 2015;10(2):e0117568.
    PMID: 25659139 DOI: 10.1371/journal.pone.0117568
    BACKGROUND: Mammographic density is a strong risk factor for breast cancer and is highly variable, but, to date, few studies have examined density in Asian women, particularly those in low and middle-income Asian countries where genetic and lifestyle determinants may be significantly different.
    METHODS: A total of 1,240 women who attended an opportunistic mammogram screening programme were eligible for analysis. Mammographic density was estimated using a fully-automated thresholding method and differences across ethnic groups were examined using linear regression in 205 randomly selected Chinese women, 138 Malay and 199 Indian women.
    RESULTS: Percent density was significantly higher in Chinese women (28.5%; 95% CI 27.0%, 30.0%) compared to Malay (24.2%; 95% CI 22.5%, 26.0%) and Indian (24.3%; 95% CI 22.8%, 25.7%) women (p<0.001), after adjustment for age, BMI, menopausal status, parity and age at first full term pregnancy. Correspondingly, adjusted nondense area was significantly lower in Chinese (72.2cm2; 95% CI 67.9cm2, 76.5cm2) women compared to Malay (92.1cm2; 95% CI 86.9cm2, 97.2cm2) and Indian (97.7cm2; 95% CI 93.4cm2, 101.9cm2) women (p<0.001), but dense area did not differ across the three ethnic groups.
    CONCLUSIONS: Our study shows that higher percent density and lower nondense area reflect the higher incidence of breast cancer in Chinese compared to Malay and Indian women in Malaysia. Known lifestyle determinants of mammographic density do not fully account for the ethnic variations observed in mammographic density in this Asian cohort.
  13. Lim KP, Hamid S, Lau SH, Teo SH, Cheong SC
    Oncol. Rep., 2007 Jun;17(6):1321-6.
    PMID: 17487385 DOI: 10.3892/or.17.6.1321
    Inactivation of the retinoblastoma (pRB) pathway is a common event in oral squamous cell carcinoma particularly through the aberrant expression of the components within this pathway. This study examines the alterations of molecules within the pRB pathway by looking at the presence of homozygous deletions in p16(INK4A) and the expression patterns of pRB, cyclin D1 and CDK4, as well as the presence of human papillomavirus (HPV) in our samples. In our study, 5/20 samples demonstrated deletions of p16(INK4A) exon 1alpha. pRB overexpression was found in 20/20 samples, the expression was mainly observed in all layers of the epithelia, particularly in the basal layer where cells are actively dividing and aberrant pRB expression was found in 12/20 samples. Cyclin D1 and CDK4 overexpression was detected in 6/20 and 2/20 samples respectively in comparison to hyperplasias where both proteins were either not expressed or expressed at minimal levels (<10%). Strikingly, HPV was found to be present in all of our samples, suggesting that HPV plays a significant role in driving oral carcinogenesis. Notably, 17/20 of our samples showed more than one alteration in the pRB pathway, however, we did not find any significant relationship between the presence of HPV, homozygous deletion of p16(INK4A) and overexpression of pRB, cyclin D1 and CDK4. Collectively, this data demonstrates that alterations in the pRB pathway are a common event and involve the aberration of more than one molecule within the pathway. Furthermore, the involvement of HPV in all our samples suggests that HPV infection may play an important role in oral carcinogenesis.
  14. Lim KP, Sharifah H, Lau SH, Teo SH, Cheong SC
    Oncol. Rep., 2005 Oct;14(4):963-8.
    PMID: 16142358 DOI: 10.3892/or.14.4.963
    The majority of global incidences of oral cancer occur in Asia, and the aetiology of oral cancer is different in Asia as it is in the West. However, whereas there is a growing understanding of the molecular mechanisms of oral cancer progression in the West, there is little progress in this understanding in Asia. In particular, the role of the p53 pathway in modulating cancer progression in Asian oral cancer remains unclear. In this study, we micro-dissected and analysed 20 well-differentiated oral squamous cell carcinoma specimens for alterations in the p53 pathway. We found that 6/20 samples contained mutations in the p53 gene which occurred in three hotspots, at codon 203, 218 and 296. Furthermore, 6/20 samples had a homozygous deletion of p14ARF, but notably p14ARF deletion and p53 mutation events were often independent and mutually exclusive. Strikingly, MDM2 was upregulated in 20/20 samples, but not in 3/3 normal tissue specimens. Taken together, these data suggest that inactivation of the p53 pathway is a frequent event in oral squamous cell carcinoma, which occurs by an aberration in one of a number of players in the p53 pathway.
  15. Ee GC, Teo SH, Rahmani M, Lim CK, Lim YM, Go R
    Nat. Prod. Res., 2011 Jun;25(10):995-1003.
    PMID: 21644180 DOI: 10.1080/14786419.2010.534471
    A new furanodihydrobenzoxanthone, artomandin (1), together with three other flavonoid derivatives, artoindonesianin C, artonol B, and artochamin A, as well as β-sitosterol were isolated from the stem bark of Artocarpus kemando. The structures of these compounds were determined on the basis of spectral evidence. All of these compounds displayed inhibition effects to a very susceptible degree in cancer cell line tests. Compound 1 also exhibited significant antioxidant capacity in the free radical 1,1-diphenyl-2-picrylhydrazyl tests.
  16. Kamarulzaman FA, Shaari K, Ho AS, Lajis NH, Teo SH, Lee HB
    Chem. Biodivers., 2011 Mar;8(3):494-502.
    PMID: 21404433 DOI: 10.1002/cbdv.201000341
    In our screening program for new photosensitizers from Malaysian biodiversity for photodynamic therapy (PDT) of cancer, MeOH extracts of ten terrestrial plants from Cameron Highlands in Pahang, Peninsular Malaysia, were tested. In a short-term 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay, 20 μg/ml each of these extracts were incubated in a pro-myelocytic leukemia cell-line, HL60, with or without irradiation with 9.6 J/cm(2) of a broad spectrum light. Three samples, Labisia longistyla, Dichroa febrifuga, and Piper penangense, were photocytotoxic by having at least twofold lower cell viability when irradiated compared to the unirradiated assay. The extract of the leaves of Piper penangense, a shrub belonging to the family Piperaceae and widely distributed in the tropical and subtropical regions in the world, was subsequently subjected to bioassay-guided fractionation using standard chromatography methods. Eight derivatives of pheophorbide-a and -b were identified from the fractions that exhibited strong photocytotoxicity. By spectroscopic analysis, these compounds were identified as pheophorbide-a methyl ester (1), (R,S)-13(2) -hydroxypheophorbide-a methyl ester (2 and 3), pheophorbide-b methyl ester (4), 13(2) -hydroxypheophorbide-b methyl ester (5), 15(2) -hydroxylactone pheophorbide-a methyl ester (6), 15(2) -methoxylactone pheophorbide-a methyl ester (7), 15(2) -methoxylactone pheophorbide-b methyl ester (8).
  17. Yoon SY, Thong MK, Taib NA, Yip CH, Teo SH
    Fam. Cancer, 2011 Jun;10(2):199-205.
    PMID: 21318382 DOI: 10.1007/s10689-011-9420-7
    Genetic counseling (GC) and genetic testing are vital risk management strategies in hereditary breast and ovarian cancer (HBOC) syndromes. Hitherto, cancer genetic testing amongst Asians has been described only in developed and high-income Asian countries. We studied the uptake and acceptance of GC and genetic testing services to Asian BRCA carriers in a middle-income country. A total of 363 patients were tested by full sequencing and large rearrangement analysis of both BRCA1 and BRCA2 genes in the Malaysian Breast Cancer (MyBrCa) Genetic Study. Of these, 49 index patients (13.5%) were found to carry deleterious mutations. GC pre- and post- result disclosures were provided and these groups of patients and their families were studied. GC and genetic testing were accepted by 82% of Malaysian patients at high risk for HBOC syndromes. However, risk assessment was limited by large, geographically dispersed, often polygamous or polyandrous families, and the lack of complete cancer registry. Cultural taboos about cancer diagnoses, social marginalization and lack of regulatory control of genetic discrimination were significant concerns. Only 78% of index patients informed their families of their risks and 11% of relatives came forward when offered free counseling and testing. Even when GC and genetic testing are provided at no cost, there remain significant societal and regulatory barriers to effective cancer genetic services in this underserved Asian population. Families believe there is a need for regulatory protection against genetic discrimination. Further studies are needed in the area of increasing awareness about the potential benefits of GC and genetic testing in Asians.
  18. Iranpour F, Merican AM, Teo SH, Cobb JP, Amis AA
    Knee, 2017 Jun;24(3):555-563.
    PMID: 28330756 DOI: 10.1016/j.knee.2017.01.011
    BACKGROUND: Patellofemoral instability is a major cause of anterior knee pain. The aim of this study was to examine how the medial and lateral stability of the patellofemoral joint in the normal knee changes with knee flexion and measure its relationship to differences in femoral trochlear geometry.

    METHODS: Twelve fresh-frozen cadaveric knees were used. Five components of the quadriceps and the iliotibial band were loaded physiologically with 175N and 30N, respectively. The force required to displace the patella 10mm laterally and medially at 0°, 20°, 30°, 60° and 90° knee flexion was measured. Patellofemoral contact points at these knee flexion angles were marked. The trochlea cartilage geometry at these flexion angles was visualized by Computed Tomography imaging of the femora in air with no overlying tissue. The sulcus, medial and lateral facet angles were measured. The facet angles were measured relative to the posterior condylar datum.

    RESULTS: The lateral facet slope decreased progressively with flexion from 23°±3° (mean±S.D.) at 0° to 17±5° at 90°. While the medial facet angle increased progressively from 8°±8° to 36°±9° between 0° and 90°. Patellar lateral stability varied from 96±22N at 0°, to 77±23N at 20°, then to 101±27N at 90° knee flexion. Medial stability varied from 74±20N at 0° to 170±21N at 90°. There were significant correlations between the sulcus angle and the medial facet angle with medial stability (r=0.78, p<0.0001).

    CONCLUSIONS: These results provide objective evidence relating the changes of femoral profile geometry with knee flexion to patellofemoral stability.

  19. Lee OS, Ahn S, Ahn JH, Teo SH, Lee YS
    Arch Orthop Trauma Surg, 2018 Feb;138(2):227-236.
    PMID: 29143167 DOI: 10.1007/s00402-017-2826-4
    INTRODUCTION: The purpose of this systematic review and meta-analysis was to evaluate the efficacy of concurrent cartilage procedures during high tibial osteotomy (HTO) for medial compartment osteoarthritis (OA) by comparing the outcomes of studies that directly compared the use of HTO plus concurrent cartilage procedures versus HTO alone.

    MATERIALS AND METHODS: Results that are possible to be compared in more than two articles were presented as forest plots. A 95% confidence interval was calculated for each effect size, and we calculated the I 2 statistic, which presents the percentage of total variation attributable to the heterogeneity among studies. The random effects model was used to calculate the effect size.

    RESULTS: Seven articles were included to the final analysis. Case groups were composed of HTO without concurrent procedures and control groups were composed of HTO with concurrent procedures such as marrow stimulation procedure, mesenchymal stem cell transplantation, and injection. The case group showed a higher hospital for special surgery score and mean difference was 4.10 [I 2 80.8%, 95% confidence interval (CI) - 9.02 to 4.82]. Mean difference of the mechanical femorotibial angle in five studies was 0.08° (I 2 0%, 95% CI - 0.26 to 0.43). However, improved arthroscopic, histologic, and MRI results were reported in the control group.

    CONCLUSION: Our analysis support that concurrent procedures during HTO for medial compartment OA have little beneficial effect regarding clinical and radiological outcomes. However, they might have some beneficial effects in terms of arthroscopic, histologic, and MRI findings even though the quality of healed cartilage is not good as that of original cartilage. Therefore, until now, concurrent procedures for medial compartment OA have been considered optional. Nevertheless, no conclusions can be drawn for younger patients with focal cartilage defects and concomitant varus deformity. This question needs to be addressed separately.

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