Displaying all 17 publications

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  1. Muniandy J, Chan KK, Bakin S
    J Gastrointest Surg, 2021 Oct;25(10):2715-2717.
    PMID: 33834378 DOI: 10.1007/s11605-021-05002-4
  2. Nadarajah VD, Chai SH, Mohammed SM, Chan KK, Kanakeswary K
    PMID: 16771215
    The objective of this study is to determine the role of carbohydrates on the toxic effect of parasporal inclusion proteins isolated from Malaysian mosquitocidal Bacillus thuringiensis (Bt) strains on erythrocytes (human and rat). Dose response analyses on the effect of these parasporal inclusions on human and rat erythrocytes suggest that toxin action is selective depending on bacterial strains and source of erythrocytes. Results from this study suggest Bt toxin is a lectin which recognizes specific plasma membrane glycoconjugate receptor(s) with a terminal residue of either D-mannose (Man), N-acetyl-D-galactosamine (GalNAc), N-acetyl-D-glucosamine (GlcNAc) or even a combination of these monosaccharides.
  3. Tan HCL, Tan JH, Nur Dzainuddin NA, Chan KK
    Ann Coloproctol, 2020 Apr;36(2):94-101.
    PMID: 32178501 DOI: 10.3393/ac.2019.05.10
    PURPOSE: The purpose of this study was to demonstrate the feasibility and safety of laparoscopic-assisted anterior resection (LAAR) for colorectal cancer in a local Asian population.

    METHODS: This is a retrospective review of all patients with colorectal cancer operated from November 2017 to October 2018. Main variables of interest were demography, type and surgery, length of stay (LOS), and the involvement of proximal and distal doughnut. Postoperative complications were analysed using chi-square or Fisher exact and Mann-Whitney tests.

    RESULTS: There were 23 patients with a mean age of 62.5 ± 12.2 years. The mean time from diagnosis to surgery was 97.1 ± 154.84 days. There were 12 patients in the LAAR group and 11 in the open anterior resection (OAR) group. Duration of surgery was shorter in OAR (129.58 ± 51.38 minutes) compared to LAAR (147.91 ± 39.37 minutes). Mean LOS was shorter in the LAAR group with 5±1.5 days compared to the OAR group of 7.42 ± 4.25 days. However, there was no significant P-value for both duration of surgery (P = 0.322) or LOS (P = 0.87). A total of 3 complications were recorded after OAR and 2 after LAAR. Both groups had clear proximal and distal margins with 16 (12-18.5) harvested lymph nodes in LAAR and 18 (16-22) in OAR, which were equal (P = 0.155).

    CONCLUSION: This study reports a shorter LOS in the minimally invasive group of 2 days with similar oncologic resection outcomes. This shows that LAAR is feasible in Malaysia and has potential outcome benefits.

  4. Raja Ram NK, Chan KK, Md Nor SF, Sagap I
    Colorectal Dis, 2020 12;22(12):2199-2203.
    PMID: 32780561 DOI: 10.1111/codi.15305
    AIM: Fistula-in-ano (FIA) is an anomalous passage between perianal skin and the anal canal or the rectum that presents many management difficulties. Ligation of intersphincteric fistula tract (LIFT) was introduced as a cost-effective sphincter-saving procedure with a reported success rate of 94.4%. Unfortunately, this procedure is technically challenging, and recently submucosal ligation of fistula tract (SLOFT), a simplification of LIFT, was proposed. Our aim was to assess the SLOFT technique over a longer follow-up period to determine its effectiveness.

    METHOD: A prospective observational study was performed in 47 patients with FIA treated by SLOFT from September 2017 to February 2019.

    RESULTS: There were 47 patients, of whom 33(70.2%) were men. The median age was 39 years (range 30-50 years). All the patients had primary FIA of cryptoglandular origin. The patients were followed up for 1 year and were postoperatively assessed at 2, 4, 12 and 24 weeks and 1 year. The median body mass index was 27.3 kg/m2 (range 24.3-29.4 kg/m2 ) and the median duration of surgery was 15 min (range 13-20 min). Most (83.0%) of the fistulas were trans-sphincteric. The success rates at the end of 24 weeks and 1 year were 87.2% and 80.9%, respectively. No postoperative incontinence was recorded.

    CONCLUSION: In our series the success rate of SLOFT was 80.9%. There were no sphincter-related complications. Repeat SLOFT was feasible for cases of recurrence. Therefore, SLOFT should be considered an alternative sphincter-saving procedure to LIFT for the management of FIA.

  5. Raja Ram NK, Chan KK, Fareeda S, Sagap I
    Colorectal Dis, 2020 12;22(12):2334-2335.
    PMID: 32946673 DOI: 10.1111/codi.15370
  6. Chan KK, Dassanayake B, Deen R, Wickramarachchi RE, Kumarage SK, Samita S, et al.
    World J Surg Oncol, 2010;8:82.
    PMID: 20840793 DOI: 10.1186/1477-7819-8-82
    This study compares clinico-pathological features in young (<40 years) and older patients (>50 years) with colorectal cancer, survival in the young and the influence of pre-operative clinical and histological factors on survival.
  7. Chan KK, Wong RS, Mohamed SM, Ibrahim TA, Abdullah M, Nadarajah VD
    PMID: 22591286
    Bacillus thuringiensis (Bt) parasporal proteins with selective anticancer activity have recently garnered interest. This study determines the efficacy and mode of cell death of Bt 18 parasporal proteins against 3 leukemic cell lines (CEM-SS, CCRF-SB and CCRF-HSB-2).Cell-based biochemical analysis aimed to determine cell viability and the percentage of apoptotic cell death in treated cell lines; ultrastructural analysis to study apoptotic changes and Western blot to identify the parasporal proteins' binding site were performed. Bt 18 parasporal proteins moderately decreased viability of leukemic cells but not that of normal human T lymphocytes. Further purification of the proteins showed changes in inhibition selectivity. Phosphatidylserine externalization, active caspase-3, cell cycle, and ultrastructural analysis confirmed apoptotic activity and S-phase cell-cycle arrest. Western blot analysis demonstrated glyceraldehyde 3-phosphate dehydrogenase as a binding protein. We suggest that Bt 18 parasporal proteins inhibit leukemic cell viability by cell-cycle arrest and apoptosis and that glyceraldehyde 3-phosphate dehydrogenase binding initiates apoptosis.
  8. Chan KK, Sundaram V, Tan J, Ho YK, Ramanan RN, Ooi CW
    J Biomol Struct Dyn, 2023 Oct 03.
    PMID: 37787564 DOI: 10.1080/07391102.2023.2262590
    As a class of ionic liquids with higher biocompatibility, cholinium aminoates ([Cho][AA]) hold potential as solvation media for enzymatic bioprocessing. Herein, solvation effect of [Cho][AA] on structural stability and enzymatic activity of Candida antarctica lipase B (CALB) was evaluated using experimental and computational approaches. Influence of [Cho][AA] on CALB stability was investigated using amino acid anions ([AA]-) with varying hydrophobicity levels. Choline phenylalaninate ([Cho][Phe]) resulted in 109.1% and 110.4% of relative CALB activity to buffer medium at 25 °C and 50 °C, respectively. Simulation results revealed the improvement of CALB's enzymatic activities by [AA]- with a strong hydrophobic character. Shielding of CALB from water molecules by [AA]- was observed. The level of CALB activity was governed by accumulation level of [AA]- at CALB's first hydration layer. The stronger interaction between His224 and Asp187 was postulated to be driven by [Cho][AA], resulting in the activity enhancement of CALB. The slight improvement of CALB activity in 0.05 M [Cho][Phe] at 50 °C could be due to the larger size of entrance to the catalytic site and the stronger interaction between the catalytic residues. The promising effect of [Cho][Phe] on CALB activation may stimulate research efforts in designing a 'fully green' bioreaction for various industrial applications.Communicated by Ramaswamy H. Sarma.
  9. Chuah JS, Tan JH, Bujang MA, Chan KK, Kosai NR
    Surg Endosc, 2024 Jun;38(6):3279-3287.
    PMID: 38658388 DOI: 10.1007/s00464-024-10841-8
    BACKGROUND: Oesophagogastroduodenoscopy (OGDS) is the most common diagnostic procedure for upper gastrointestinal diseases. It often causes discomfort and anxiety, which are only mitigated by systemic sedation. However, sedation poses additional risks of adverse cardiopulmonary events, increased medical costs, and prolonged recovery. Transcutaneous electrical nerve stimulation of acupuncture points (Acu-TENS) is a non-invasive and innovative approach that induces analgesic effect during endoscopy. This trial is the first to be reported in English that explores the potential of Acu-TENS to increase patient tolerance during non-sedated elective diagnostic OGDS.

    METHODS: A double-blinded randomized controlled trial involving 348 subjects was conducted at a tertiary hospital to evaluate the success rate of OGDS with Acu-TENS. Subjects aged 18-75 years scheduled for their first elective diagnostic OGDS were randomized into the intervention (Acu-TENS) and placebo arms. OGDS success was assessed based on subjects' satisfaction ratings on a Likert scale and procedure's technical adequacy. Secondary measures included subjects' willingness to undergo future OGDS under similar conditions, procedure duration, and the endoscopist's perceived ease of the procedure.

    RESULTS: OGDS success rates were significantly higher with Acu-TENS (77.8%) than with the placebo (68.0%; odds ratio [OR] 1.64, 95% confidence interval [CI] 1.01-2.66, p = 0.043). Subjects who received Acu-TENS expressed higher willingness for future OGDS (78.9%) than those who received the placebo (68.6%; OR 1.71, 95% CI 1.04-2.79, p = 0.031). Procedure duration were significantly shorter in the intervention arm (6.0 min) than in the placebo arm (10.0 min; p = 0.002). No adverse effects were reported, and endoscopists perceived similar procedure ease in both arms.

    CONCLUSIONS: Acu-TENS improved OGDS success and enhanced patients' experiences during non-sedated OGDS. It demonstrated safety with no side effects and reduced the procedure completion time. It could be used as an adjunct in non-sedated diagnostic OGDS.

  10. Chan KK, Pereira AF, Valente AI, Tavares APM, Coutinho JAP, Ooi CW
    Int J Biol Macromol, 2024 Oct;277(Pt 4):134443.
    PMID: 39217672 DOI: 10.1016/j.ijbiomac.2024.134443
    Laccases hold great potential for biotechnological applications, particularly in environmental pollutant remediation. Laccase activity is governed by the solvent environment, and ionic liquids (ILs) emerge as a versatile solvent for activation or stabilization of enzymes. Herein, effects of cholinium-based ILs formulated with carboxylic acids, inorganic acid, and amino acids as anionic species, on the catalytic activity of laccase from Trametes versicolor were investigated by experimental and computational approaches. Experimental results showed that laccase activity was enhanced by 21.39 % in 0.5 M cholinium dihydrogen citrate ([Cho][DHC]), in relation to the laccase activity in phosphate buffer medium. However, cholinium aminoate ILs negatively affected laccase activity, as evidenced by the partial deactivation of laccase in both cholinium glycinate and cholinium phenylalaninate, at concentrations of 0.1 M and 0.5 M, respectively. Molecular dynamics studies revealed that the enhancement of laccase activity in [Cho][DHC] might be attributed to the highly stabilized and compact structure of laccase, facilitating a better internal electron transfer during the laccase-substrate interactions. Enhanced catalytic performance of laccase in [Cho][DHC] was postulated to be driven by the high accumulation level of dihydrogen citrate anions around laccase's surface. [Cho][DHC] holds great promise as a cosolvent in laccase-catalyzed biochemical reactions.
  11. Joan Gan CY, Chan KK, Tan JH, Tan Chor Lip H, Louis Ling LL, Mohd Azman ZA
    ANZ J Surg, 2021 06;91(6):E375-E381.
    PMID: 33876547 DOI: 10.1111/ans.16870
    BACKGROUND: Smartphone-controlled patch electro-acupuncture (SCEA) is a novel device which gives the same analgesic effect as with conventional acupuncture. There are no published articles in the English literature on the use of this device as a primary mode of pain relief during colonoscopy. Primary aims of this study were to investigate the efficacy of SCEA as a substitute for pain relief during colonoscopy.

    METHODS: Thirty-seven patients were randomized to receive SCEA (n = 19) or placebo (n = 18) during colonoscopy. Additional rescue sedation was administered to patients if they had pain or discomfort during the procedure. Visual analogue scale was used to quantify the intensity of pain from the beginning to end of the procedure. Other variables analysed were the amount of sedation used, duration from start to caecal intubation, length of time for completion of colonoscopy and recovery time to home discharge.

    RESULTS: Patients who received SCEA had a lower median pain score of 4.6 (interquartile range 5.7) compared to the placebo group of 6.0 (interquartile range 3.2). Statistical analysis comparing the groups revealed a non-significant P-value of 0.12, although more than 90% of the patients indicated willingness for SCEA as the primary analgesia if they were to repeat the procedure. Throughout the study, there were no adverse complications that occurred during the use of SCEA.

    CONCLUSIONS: Even though this study did not demonstrate, a significance in pain reduction, SCEA remains a safe modality which, more than 90% of patients favoured as a substitute for pain relief during colonoscopy.

  12. Phipps ME, Chan KK, Naidu R, Mohamad NW, Hoh BP, Quek KF, et al.
    BMC Public Health, 2015 Jan 31;15:47.
    PMID: 25636170 DOI: 10.1186/s12889-015-1384-3
    BACKGROUND: South East Asia (SEA) is home to over 30 tribes of indigenous population groups who are currently facing rapid socio-economic change. Epidemiological transition and increased prevalence of non-communicable diseases (NCD) has occured. In Peninsular Malaysia, the Orang Asli (OA) indigenous people comprise 0 · 6% (150,000) of the population and live in various settlements. OA comprise three distinct large tribes with smaller sub-tribes. The three large tribes include Proto-Malay (sub-tribes: Orang Seletar and Jakun), Senoi (sub-tribes: Mahmeri and Semai), and Negrito (sub-tribes: Jehai, Mendriq and Batek).

    METHODS: We studied the health of 636 OA from seven sub-tribes in the Peninsular. Parameters that were assessed included height, weight, BMI and waist circumference whilst blood pressure, cholesterols, fasting blood glucose and HbA1c levels were recorded. We then analysed cardio-metabolic risk factor prevalences and performed multiple pair-wise comparisons among different sub-tribes and socio-economic clusters.

    RESULTS: Cardio-metabolic risk factors were recorded in the seven sub-tribes.. Prevalence for general and abdominal obesity were highest in the urbanized Orang Seletar (31 · 6 ± 5 · 7%; 66 · 1 ± 5 · 9%). Notably, hunter gatherer Jehai and Batek tribes displayed the highest prevalence for hypertension (43 · 8 ± 9 · 29% and 51 · 2 ± 15 · 3%) despite being the leanest and most remote, while the Mendriq sub-tribe, living in the same jungle area with access to similar resources as the Batek were less hypertensive (16.3 ± 11.0%), but displayed higher prevalence of abdominal obesity (27.30 ± 13.16%).

    CONCLUSIONS: We describe the cardio-metabolic risk factors of seven indigenous communities in Malaysia. We report variable prevalence of obesity, cholesterol, hypertension and diabetes in the OA in contrast to the larger ethnic majorities such as Malays, Chinese and Indians in Malaysia These differences are likely to be due to socio-economic effects and lifestyle changes. In some sub-tribes, other factors including genetic predisposition may also play a role. It is expected that the cardio-metabolic risk factors may worsen with further urbanization, increase the health burden of these communities and strain the government's resources.

  13. Wilailak S, Chan KK, Chen CA, Nam JH, Ochiai K, Aw TC, et al.
    J Gynecol Oncol, 2015 Jan;26(1):46-53.
    PMID: 25310857 DOI: 10.3802/jgo.2015.26.1.46
    The purpose of this study was to develop a risk prediction score for distinguishing benign ovarian mass from malignant tumors using CA-125, human epididymis protein 4 (HE4), ultrasound findings, and menopausal status. The risk prediction score was compared to the risk of malignancy index and risk of ovarian malignancy algorithm (ROMA).
  14. Lim KL, Johari NA, Wong ST, Khaw LT, Tan BK, Chan KK, et al.
    PLoS One, 2020;15(8):e0238417.
    PMID: 32857823 DOI: 10.1371/journal.pone.0238417
    The rapid global spread of the coronavirus disease (COVID-19) has inflicted significant health and socioeconomic burden on affected countries. As positive cases continued to rise in Malaysia, public health laboratories experienced an overwhelming demand for COVID-19 screening. The confirmation of positive cases of COVID-19 has solely been based on the detection of the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) using real-time reverse transcription polymerase chain reaction (qRT-PCR). In efforts to increase the cost-effectiveness and efficiency of COVID-19 screening, we evaluated the feasibility of pooling clinical Nasopharyngeal/Oropharyngeal (NP/OP) swab specimens during nucleic acid extraction without a reduction in sensitivity of qRT-PCR. Pools of 10 specimens were extracted and subsequently tested by qRT-PCR according to the WHO-Charité protocol. We demonstrated that the sample pooling method showed no loss of sensitivity. The effectiveness of the pooled testing strategy was evaluated on both retrospective and prospective samples, and the results showed a similar detection sensitivity compared to testing individual sample alone. This study demonstrates the feasibility of using a pooled testing strategy to increase testing capacity and conserve resources, especially when there is a high demand for disease testing.
  15. Chen YH, Leong WS, Lin MS, Huang CC, Hung CS, Li HY, et al.
    JACC Cardiovasc Interv, 2016 09 12;9(17):1825-32.
    PMID: 27609258 DOI: 10.1016/j.jcin.2016.06.015
    OBJECTIVES: This study sought to determine predictors for successful endovascular treatment in patients with chronic carotid artery occlusion (CAO).

    BACKGROUND: Endovascular recanalization in patients with chronic CAO has been reported to be feasible, but technically challenging.

    METHODS: Endovascular attempts in 138 consecutive chronic CAO patients with impaired ipsilateral hemisphere perfusion were reviewed. We analyzed potential variables including epidemiology, symptomatology, angiographic morphology, and interventional techniques in relation to the technical success.

    RESULTS: The technical success rate was 61.6%. Multivariate analysis showed absence of prior neurologic event (odds ratio [OR]: 0.27; 95% confidence interval [CI]: 0.10 to 0.76), nontapered stump (OR: 0.18; 95% CI: 0.05 to 0.67), distal internal carotid artery (ICA) reconstitution via contralateral injection (OR: 0.19; 95% CI: 0.05 to 0.75), and distal ICA reconstitution at communicating or ophthalmic segments (OR:0.12; 95% CI: 0.04 to 0.36) to be independent factors associated with lower technical success. Point scores were assigned proportional to model coefficients, and technical success rates were >80% and <40% in patients with scores of ≤1 and ≥4, respectively. The c-indexes for this score system in predicting technical success was 0.820 (95% CI: 0.748 to 0.892; p < 0.001) with a sensitivity of 84.7% and a specificity of 67.9%.

    CONCLUSIONS: Absence of prior neurologic event, nontapered stump, distal ICA reconstitution via contralateral injection, and distal ICA reconstitution at communicating or ophthalmic segments were identified as independent negative predictors for technical success in endovascular recanalization for CAO.

  16. Voon K, Johari NA, Lim KL, Wong ST, Khaw LT, Wong SF, et al.
    Bio Protoc, 2021 May 05;11(9):e4005.
    PMID: 34124305 DOI: 10.21769/BioProtoc.4005
    The COVID-19 pandemic requires mass screening to identify those infected for isolation and quarantine. Individually screening large populations for the novel pathogen, Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), is costly and requires a lot of resources. Sample pooling methods improve the efficiency of mass screening and consume less reagents by increasing the capacity of testing and reducing the number of experiments performed, and are therefore especially suitable for under-developed countries with limited resources. Here, we propose a simple, reliable pooling strategy for COVID-19 testing using clinical nasopharyngeal (NP) and/or oropharyngeal (OP) swabs. The strategy includes the pooling of 10 NP/OP swabs for extraction and subsequent testing via quantitative real-time reverse transcription polymerase chain reaction (RT-qPCR), and may also be applied to the screening of other pathogens.
  17. Nalairndran G, Hassan Abdul Razack A, Mai CW, Fei-Lei Chung F, Chan KK, Hii LW, et al.
    J Cell Mol Med, 2020 Oct;24(20):12188-12198.
    PMID: 32926495 DOI: 10.1111/jcmm.15876
    Prostate cancer (PCa) is the most common malignancy and is the second leading cause of cancer among men globally. Using a kinome-wide lentiviral small-hairpin RNA (shRNA) library screen, we identified phosphoinositide-dependent kinase-1 (PDPK1) as a potential mediator of cell survival in PCa cells. We showed that knock-down of endogenous human PDPK1 induced significant tumour-specific cell death in PCa cells (DU145 and PC3) but not in the normal prostate epithelial cells (RWPE-1). Further analyses revealed that PDPK1 mediates cancer cell survival predominantly via activation of serum/glucocorticoid-regulated kinase 3 (SGK3). Knock-down of endogenous PDPK1 in DU145 and PC3 cells significantly reduced SGK3 phosphorylation while ectopic expression of a constitutively active SGK3 completely abrogated the apoptosis induced by PDPK1. In contrast, no such effect was observed in SGK1 and AKT phosphorylation following PDPK1 knock-down. Importantly, PDPK1 inhibitors (GSK2334470 and BX-795) significantly reduced tumour-specific cell growth and synergized docetaxel sensitivity in PCa cells. In summary, our results demonstrated that PDPK1 mediates PCa cells' survival through SGK3 signalling and suggest that inactivation of this PDPK1-SGK3 axis may potentially serve as a novel therapeutic intervention for future treatment of PCa.
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