Displaying publications 1 - 20 of 69 in total

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  1. Genomics, health, and society
    Chan CK
    New Solut, 2002;12(2):109-19.
    PMID: 17208760
    On June 27, 2001, the World Health Organization conducted hearings in Geneva for a Special Report on Genomics & Health. Initially intended as a document to address the ethical, legal, and social implications of the gathering genomics resolution (ELSI), the terms of reference of the report were significantly modified to give primary emphasis to a scientific and technological assessment of the implications of genomics for human health. The Citizens' Health Initiative, one of two NGOs invited to make submissions at these consultations, suggested that no less important than the scientific and technical assessment was a perspective which gave due attention to the social context and political economy of scientific/technological development and its deployment. The article below touches upon neglected health priorities of poor countries, intellectual property rights and patents, risk management, insurance and discrimination, and predictive (prenatal) testing, reproductive choice, and eugenics.
  2. A Simple Cable Method for Intraoperative Limb Alignment Assessment
    Chan CK, Shanmugam R
    Malays Orthop J, 2016 Mar;10(1):69-70.
    PMID: 28435552
  3. Promoting physical activity with goal-oriented mental imagery: a randomized controlled trial
    Chan CK, Cameron LD
    J Behav Med, 2012 Jun;35(3):347-63.
    PMID: 21695405 DOI: 10.1007/s10865-011-9360-6
    Self-regulation theory and research suggests that different types of mental imagery can promote goal-directed behaviors. The present study was designed to compare the efficacy of approach imagery (attainment of desired goal states) and process imagery (steps for enacting behavior) in promoting physical activity among inactive individuals. A randomized controlled trial was conducted with 182 inactive adults who received one of four interventions for generating mental images related to physical activity over a 4-week period, with Approach Imagery (approach versus neutral) and Process Imagery (process versus no process) as the intervention strategies. Participants received imagery training and practiced daily. Repeated measures ANOVAs revealed that Approach Imagery: (1) increased approach motivations for physical activity at Week 4; (2) induced greater intentions post-session, which subsequently induced more action planning at Week 4; (3) enhanced action planning when combined with process images at post-session and Week 1; and (4) facilitated more physical activity at Week 4 via action planning. These findings suggest that inducing approach orientation via mental imagery may be a convenient and low-cost technique to promote physical activity among inactive individuals.
  4. Fulltext Ipsilateral femoral fracture non-union and delayed union treated by hybrid plate nail fixation and vascularized fibula bone grafting: a case report
    Chan C, Ng W, Merican A
    Malays Orthop J, 2013 Jul;7(2):41-4.
    PMID: 25722826 MyJurnal DOI: 10.5704/MOJ.1307.012
    Non-union is a well recognized complication of femoral neck fractures. The decision whether to attempt fracture fixation or to resort to hip replacement is particularly difficult in patients in the borderline age group in whom complex attempts at gaining union may fail and later present a difficult revision. On the other hand the patient may be young enough that arthroplasty best be avoided . Besides, presence of ipsilateral femoral shaft fracture with delayed union in addition to the femoral neck non-union will pose major problems at operation. We share our experience in treating a femoral neck fracture non-union with ipsilateral femoral shaft delayed union in the shaft and in the distal femur in a fifty years old patient. The fracture was treated with an angle blade plate and supracondylar nail supplemented with a free vascularised fibular bone grafting and autologous cancellous graft. There was radiological union at fourth month. At sixth months, the patient was free of pain and able to walk without support. Thus, we would like to suggest that vascularised fibula bone grafting with supracondylar nailing is a viable option for this pattern of fracture.
  5. Diluted povidone-iodine versus saline for dressing metal-skin interfaces in external fixation
    Chan CK, Saw A, Kwan MK, Karina R
    J Orthop Surg (Hong Kong), 2009 Apr;17(1):19-22.
    PMID: 19398787
    To compare infection rates associated with 2 dressing solutions for metal-skin interfaces.
  6. Fulltext A simple practical protocol for care of metal-skin interface of external fixation
    Saw A, Chan CK, Penafort R, Sengupta S
    Med J Malaysia, 2006 Feb;61 Suppl A:62-5.
    PMID: 17042233
    Patients treated with external fixation for limb reconsturciton or fracture stabilization equire regular and prolongedperiod of pin-tract care involving frequent visits to clinic and dressing traditionally carried out by trained nurses or medical assistants. A simple method of do-it-yourself dressing was introduced in our institution and this study was undertaken to evaluate the effectiveness of the protocol. Sixty patients (40 trauma-related problems and 20 congenital or developmental disorders) were enrolled into the study. Following application of external fixation, the patients and/or their caretakers were taught on how to do pin-site dressing using normal saline or drinking water as cleansing solution on daily basis. Patients were discharged on the second or third post-operative day and were followed-up every two weeks for an average 182 days (range 66 to 379 days) with special attention on identifying pin-tract infection. A simple grading system for pin-tract infections was proposed. Of 40 patients with trauma-related problems. 65% were post-traumatic infections. There were 788 metal-skin interfaces (239 half-pin fixations and 549 tensioned wire fixations. A total 143 metal-skin interface infections (18.1%) involving half-pin sites (41.3%) and tensioned wire sites (58.7%) was noted. Majority were grade I infections (79.7%), 18.8% grade II and only 1.4% grade III. Most infections (81%)were caused by Staphylococcus aureus. Grade I infections were successfully treated with frequent dressing, grade II by adjunctive oral antibiotic but grade III infections required removal of fixator. All eventually healed. Do yourself non-sterile dressing of metal-skin interfaces is a cost-effective method of pin-site care with a low infection rate. The infections were sucessfully treated using guidelines according to the proposed classification of pin-tract infections.
  7. Fulltext Penang cancer cases reported to the National Cancer Registry of Malaysia, 1987-1990: an epidemiological analysis
    Chan CK, Singh J, Rasid BK, Devaraj T
    Med J Malaysia, 1994 Jun;49(2):122-31.
    PMID: 8090090
    2,124 cases of cancer diagnosed and/or treated in Penang between 1987-1990 were reported to the National Cancer Registry of Malaysia by hospitals in Penang. 1,762 met the criteria for Penang incident cases first diagnosed between 1987-1990, and were the subjects on which all subsequent analyses were based. 85 per cent of case notifications were from Mount Miriam Hospital. Among males, all-site cancer incidence rates (age-standardised) were highest among Chinese, and lowest among Malays. Among females, the Indian female incidence rate was highest, higher than that of any other ethnic-gender sub-group. Site-specific cancer rates varied according to ethnicity and gender, but overall the four most frequent cancers reported from Penang were breast, lung, cervix and nasopharynx cancers. It needs to be emphasised that all these results are highly tentative since they are based on notified cancer occurrences and hence are very uncertain proxies for true cancer incidence. Based on incidence rates from the Singapore Cancer Registry (1978-1982), the expected number of incident cases in 1989 for Penang (Malays, Chinese and Indians combined) was 1,561. The number notified to the National Cancer Registry was 496. This underlines the tentative nature of this analysis of the returns for 1987-1990 from Penang.
  8. Web-based interventions for the management of type 2 diabetes mellitus: a systematic review of recent evidence
    Ramadas A, Quek KF, Chan CK, Oldenburg B
    Int J Med Inform, 2011 Jun;80(6):389-405.
    PMID: 21481632 DOI: 10.1016/j.ijmedinf.2011.02.002
    Introduction: The Internet has emerged as a potentially effective medium for information exchange. The Internet's potential has been recognised and web-based education programmes have been steadily adopted in recent years in preventing and managing chronic diseases such as diabetes mellitus. This review provides a descriptive discussion of web-based behavioural interventions for the management of type 2 diabetes mellitus.
    Method: Systematic literature searches were performed using MEDLINE, EMBASE, PUBMED, PsycINFO, Web of Science and Cochrane Library to retrieve articles published between 2000 and June 2010 which fulfilled all inclusion criteria. Methodological quality assessment and data synthesis were then performed.
    Results: Twenty articles representing 13 different studies were reviewed. None of the studies were ranked as low in the methodological quality. Goal-setting, personalised coaching, interactive feedback and online peer support groups were some of the successful approaches which were applied in e-interventions to manage type 2 diabetes mellitus. Strong theoretical background, use of other technologies and longer duration of intervention were proven to be successful strategies as well.
    Conclusion: The web-based interventions have demonstrated some level of favourable outcomes, provided they are further enhanced with proper e-research strategies.
  9. Fulltext The brief introduction to organizational citizenship behaviors and counterproductive work behaviors: a literature review
    Fan Q, Wider W, Chan CK
    Front Psychol, 2023;14:1181930.
    PMID: 37780163 DOI: 10.3389/fpsyg.2023.1181930
    This paper presents a literature review on the topic of organizational performance. The study conceptualizes the overall performance of the organization as comprising of organizational citizenship behaviors (OCB) and counterproductive work behaviors (CWB). While there are numerous research studies on OCB, not many have focused on how OCB and CWB affect organizational performance simultaneously. The paper provides an explanation of the OCB and CWB concepts, followed by the primary research and focus of the study. The article presents a comprehensive framework for understanding the meanings of OCB and CWB, along with an internal hierarchy. This framework will serve as a beneficial resource for working managers, academics, and researchers, who seek to optimize economic productivity through improved understanding and management of OCB and CWB.
  10. Swietenia macrophylla King induces mitochondrial-mediated apoptosis through p53 upregulation in HCT116 colorectal carcinoma cells
    Goh BH, Chan CK, Kamarudin MN, Abdul Kadir H
    J Ethnopharmacol, 2014 Apr 28;153(2):375-85.
    PMID: 24613274 DOI: 10.1016/j.jep.2014.02.036
    Swietenia macrophylla King is a traditional herb used to treat various diseases including hypertension, diabetes and cancer. Previous study demonstrated its anti-tumor effect but the potential mechanisms have not been clearly defined. The current study was to further investigate the underlying mechanism of ethyl acetate fraction of Swietenia macrophylla (SMEAF)-induced anti-proliferative effect and apoptosis in HCT116 colorectal carcinoma cell.
  11. Fulltext Femoral Shaft Cortical Pathology associated with longterm Alendronate Therapy: A New Classification
    Kwan M, Chan C, Ng W, Merican A, Chung W, Chan S
    Malays Orthop J, 2013 Jul;7(2):12-7.
    PMID: 25722819 MyJurnal DOI: 10.5704/MOJ.1307.008
    There are reported cases of cortical reaction over the tension side of the normal femoral shafts in patients on long term treatment with alendronate, leading to subsequent femoral shaft fractures. We performed a retrospective review of patients with low-energy femoral shaft fracture on alendronate, admitted to our institution during the period 2004 to May 2009. The presence of radiological changes of cortical hypertrophy with or without Looser's zone over the tension side of the femoral bone (normal limb) was determined and correlated with clinical symptoms. Thirteen patients were identified. Average duration of alendronate use was 6.5 ± 3.3 years (ranges, two to 10 years). These radiological changes were noted in four patients. Average duration of alendronate usage in these four patients was 6.5 ± 2.4 years (ranges, 5 to10 years). Prodromal thigh pain was present in a patient, who had cortical hypertrophy with the presence of a Looser's zone traversing the cortex on the femoral shaft. One patient had Looser's zone limited at the lateral hypertrophied cortex without prodromal pain. The interobserver kappa coefficient was 0.96. A femoral radiograph should be performed in all patients who are on long-term alendronate therapy who present with thigh pain. We propose a new grading system based on our observation of the radiological features in these four cases. This new grading of the radiological spectrum of femoral shaft cortical pathology has the potential to stratify the risk of low energy femoral fracture for patients treated with long-term alendronate therapy.
  12. Religiosity, dietary habit, intake of fruit and vegetable, and vegetarian status among Seventh-Day Adventists in West Malaysia
    Tan MM, Chan CK, Reidpath DD
    J Behav Med, 2016 08;39(4):675-86.
    PMID: 27010212 DOI: 10.1007/s10865-016-9736-8
    Religion has been shown to be salutary on health, and a possible link between religion and positive health outcomes is diet. Research has shown that religiosity is associated with better diet but most studies were conducted in a multi-denominational context, which might be confounded with theological differences. This study examined the relationship between religiosity and diet within a homogenous group of believers. Data from survey of 574 Seventh-Day Adventists residing in West Malaysia, aged 18-80, were analyzed using multiple regressions. While none of the religious variables were significantly associated with fruit and vegetable intake, a higher level of religiosity was associated with a better dietary habit and vegetarian status. The mixed relationship between religiosity and diet suggest that further research is needed to explore how religion might influence the diet of adherents.
  13. Fulltext Deoxyelephantopin from Elephantopus scaber Inhibits HCT116 Human Colorectal Carcinoma Cell Growth through Apoptosis and Cell Cycle Arrest
    Chan CK, Chan G, Awang K, Abdul Kadir H
    Molecules, 2016 Mar 21;21(3):385.
    PMID: 27007366 DOI: 10.3390/molecules21030385
    Deoxyelephantopin (DET), one of the major sesquiterpene lactones derived from Elephantopus scaber was reported to possess numerous pharmacological functions. This study aimed to assess the apoptosis inducing effects and cell cycle arrest by DET followed by elucidation of the mechanisms underlying cell death in HCT116 cells. The anticancer activity of DET was evaluated by a MTT assay. Morphological and biochemical changes were detected by Hoescht 33342/PI and Annexin V/PI staining. The results revealed that DET and isodeoxyelephantopin (isoDET) could be isolated from the ethyl acetate fraction of E. scaber leaves via a bioassay-guided approach. DET induced significant dose- and time-dependent growth inhibition of HCT116 cells. Characteristics of apoptosis including nuclear morphological changes and externalization of phosphatidylserine were observed. DET also significantly resulted in the activation of caspase-3 and PARP cleavage. Additionally, DET induced cell cycle arrest at the S phase along with dose-dependent upregulation of p21 and phosphorylated p53 protein expression. DET dose-dependently downregulated cyclin D1, A2, B1, E2, CDK4 and CDK2 protein expression. In conclusion, our data showed that DET induced apoptosis and cell cycle arrest in HCT116 colorectal carcinoma, suggesting that DET has potential as an anticancer agent for colorectal carcinoma.
  14. Elephantopus scaber induces apoptosis through ROS-dependent mitochondrial signaling pathway in HCT116 human colorectal carcinoma cells
    Chan CK, Supriady H, Goh BH, Kadir HA
    J Ethnopharmacol, 2015 Jun 20;168:291-304.
    PMID: 25861953 DOI: 10.1016/j.jep.2015.03.072
    Elephantopus scaber also known as Elephant's foot (Asteraceae family) has a plethora of traditional applications including dysuria, diarrhea, dysentery, leukemia and cancer. This study aimed to investigate the apoptosis inducing effects of E. scaber and the underlying mechanisms in HCT116 colorectal cell line.
  15. Fulltext Femoral Neck Non-Union - A Biomechanical Solution with Valgus Sliding Subtrochanteric Osteotomy: A Case Report
    Teh KH, Ruben JK, Chan CK, Abbas AA
    Malays Orthop J, 2020 Jul;14(2):134-137.
    PMID: 32983389 DOI: 10.5704/MOJ.2007.022
    Avascular necrosis and non-union are two most dreaded complications of femoral neck fracture fixations. Hip replacement seems to be a simple solution for this complex problem. However, the long-term efficacy of prosthetic replacement in the young population with higher functional demand is still questionable. Femoral head preserving valgus subtrochanteric osteotomies in properly selected cases have strong support from literature. The conventional technique of valgus subtrochanteric osteotomy involves lateral based wedge resection. Alternatively, a simpler sliding oblique subtrochanteric osteotomy without any wedge removal can also be performed. We hereby describe a successful case of sliding subtrochanteric osteotomy with 135° dynamic hip screw (DHS) plate fixation in treating non-union neck of femur fracture in a young gentleman.
  16. Fulltext Midterm Results of Conversion from Failed Bipolar Hemiarthroplasty to Total Hip Arthroplasty
    Park KS, Chan CK, Lee DH, Yoon TR
    Indian J Orthop, 2018 8 7;52(4):369-373.
    PMID: 30078894 DOI: 10.4103/ortho.IJOrtho_494_16
    Background: Conversion from failed bipolar hemiarthroplasty (HA) to total hip arthroplasty (THA) presents a great challenge to orthopedic surgeons for bipolar head removal and cup placement with or without change of femoral stem. Conversion THA after failed bipolar arthroplasty is known to offer both symptomatic and functional improvement. This study evaluates the midterm functional outcome and complications, especially dislocation associated with femoral head diameter, after conversion THA.

    Materials and Methods: Forty eight hips with the conversion of bipolar HA to THA were followed up for an average 6.2 years (range 2.0-11.5 years). Twenty one hips had conversion surgery to THA using metal-on-metal articulation (28 or 32 mm head). Nine hips used ceramic-on-ceramic (28-40 mm) and eighteen hips used large head metal-on-metal bearing (>40 mm). Outcome was evaluated using Harris Hip Score (HHS) and Western Ontario McMaster Universities Osteoarthritis Index (WOMAC) score. The radiographs were analyzed for evidence of osteolysis and/or loosening. The complications were evaluated, especially dislocation with different femoral head diameter.

    Results: Average HHS significantly improved from 42 preoperatively to 86 postoperatively and the average WOMAC score also significantly improved from 47 to 22 postoperatively. Radiological evaluation showed all the femoral components were stable. There was one acetabular component loosening, which required revision 9 years after conversion to THA. One dislocation and one recurrent dislocation were recorded in isolated acetabular revision hip; whereas one dislocation, one recurrent dislocation, and one trochanteric nonunion occurred in the hips with revision of both components. All dislocations occurred in hips with a femoral head size of 28 mm (P = 0.052). The cup and femoral head interval length was the most significant factor contributing to dislocation (P = 0.013).

    Conclusions: Conversion THA after failed bipolar HA offers a reliable pain relief and functional improvement. To prevent dislocation, it is highly recommended to use a larger diameter femoral head, especially where the cup size is big.

  17. Fulltext Multicentric Disappearing Bone Disease treated with Arthroplasty
    Chan CK, Mohamed RM, Azlina AA, Azhar MM
    Malays Orthop J, 2016 Nov;10(3):42-45.
    PMID: 28553448 MyJurnal DOI: 10.5704/MOJ.1611.004
    Multicentric disappearing bone disease, or Gorham disease, is a rare entity. A middle age woman, presented to us with left sided antalgic gait and severe bony deformity of her left knee. Radiograph revealed massive bone defect of the medial condyle of the left tibia with subluxation of the knee joint. She was scheduled for knee replacement in six months. However, she developed another lesion over the right hip that typically mimicked the disease progression of disappearing bone disease. The right femoral head vanished progressively within three months without significant history of infection or trauma. Subsequent bone biopsy of the right femoral head and left tibia condyle confirmed the diagnosis. Total knee replacement was carried out for her left knee. She remained pain free on her left knee. A year later, after confirming by sequential radiographs that the osteolysis had stopped, total right hip replacement was performed. Five years later, she remained pain free and both the arthroplasties were stable.
  18. Persistent noise after ceramic-on-ceramic total hip replacement due to bearing coupling size mismatch: A case report
    Chan CK, Lee DH, Yoon TR, Park KS
    J Orthop Sci, 2019 09;24(5):936-938.
    PMID: 28390755 DOI: 10.1016/j.jos.2017.03.010
  19. Dioscorea bulbifera induced apoptosis through inhibition of ERK 1/2 and activation of JNK signaling pathways in HCT116 human colorectal carcinoma cells
    Ahmad Hidayat AF, Chan CK, Mohamad J, Abdul Kadir H
    Biomed Pharmacother, 2018 Aug;104:806-816.
    PMID: 29860114 DOI: 10.1016/j.biopha.2018.05.073
    Dioscorea bulbifera, also known as air potato, has been cultivated as food crop mainly in tropical countries in Asia and Australia. The tubers are edible and have often been used in Traditional Chinese Medicine (TCM) and Ayurvedic medicine to treat cancer, diabetes, thyroid disease, and inflammation. This study aimed to investigate the effects of D. bulbifera on HCT116 human colorectal carcinoma cells and to unravel the plausible mechanisms underlying its apoptotic effects. The ethanol crude and fractions (hexane, ethyl acetate and water) of D. bulbifera were subjected to cell viability MTT assay against various cancer cell lines. The lowest IC50 of the extract and fractions on selected cancer cells were selected for further apoptosis assay and western blot analysis. HCT116 cancer cells were treated with D. bulbifera and stained with Annexin/PI or Hoechst 33342/PI for preliminary confirmation of apoptosis. The dissipation of mitochondria membrane potential (MMP) was determined by flow cytometry. The protein expressions of apoptosis-related proteins such as Bcl-2 family, caspases, Fas, PARP, ERK1/2 and JNK were detected by western blot analysis. Moreover, the HCT116 cells were treated with UO126 and SP600125 inhibitors to verify the involvement of ERK1/2 and JNK protein expressions in inducing apoptotic cell death. Based on the result, D. bulbifera ethyl acetate fraction (DBEAF) exhibited the most compelling cytotoxicity on HCT116 cells with an IC50 of 37.91 ± 1.30 µg/mL. The induction of apoptosis was confirmed by phosphatidylserine externalization and chromatin condensation. Depolarization of MMP further conferred the induction of apoptosis was through the regulation of Bcl-2 family proteins. Activation of caspase cascades (caspase-3, -9, -8 and -10) was elicited followed by the observation of cleaved PARP accumulation in DBEAF-treated cells. Furthermore, death receptor, Fas was activated upon exposure to DBEAF. Collective apoptotic evidences suggested the involvement of intrinsic and extrinsic pathways by DBEAF in HCT116 cells. Interestingly, the attenuation of ERK1/2 phosphorylation accompanied by the activation of JNK was detected in DBEAF-treated cells. In conclusion, the findings revealed that DBEAF induced apoptosis through intrinsic and extrinsic pathways involving ERK1/2 and JNK.
  20. Leptospermum flavescens Sm. protect pancreatic β cell function from streptozotocin involving apoptosis and autophagy signaling pathway in in vitro and in vivo case study
    Hidayat AFA, Chan CK, Mohamad J, Kadir HA
    J Ethnopharmacol, 2018 Nov 15;226:120-131.
    PMID: 30118836 DOI: 10.1016/j.jep.2018.08.020
    ETHNOPHARMACOLOGICAL IMPORTANCE: Leptospermum flavescens has been used traditionally in Malaysia to treat various ailments such as constipation, hypertension, diabetes and cancer.

    AIM OF STUDY: To investigate the potential protective effects of L. flavescens in pancreatic β cells through inhibition of apoptosis and autophagy cell death mechanisms in in vitro and in vivo models.

    MATERIALS AND METHODS: L. flavescens leaves were extracted using solvent in increasing polarities: hexane, ethyl acetate, methanol and water. All extracts were tested for INS-1 β cells viability stimulated by streptozotocin (STZ). The extract which promotes the highest cell protective activity was further evaluated for insulin secretion, apoptosis and autophagy signaling pathways. Then, the acute toxicity of extract was carried out in SD rats according to OECD 423 guideline. The active extract was tested in diabetic rats where the pancreatic β islets were evaluated for insulin, apoptosis and autophagy protein.

    RESULTS: The methanolic extract of L. flavescens (MELF) was found to increase INS-1 β cells viability and insulin secretion against STZ. In addition, MELF has been shown to inhibit INS-1 β cells apoptosis and autophagy activity. Notably, there was no toxicity observed in SD rats when administered with MELF. Furthermore, MELF exhibited anti-hyperglycemic activity in diabetic rats where apoptosis and autophagy protein expression was found to be suppressed in pancreatic β islets.

    CONCLUSION: MELF was found to protect pancreatic β cells function from STZ-induced apoptosis and autophagy in in vitro and in vivo.

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