Displaying publications 21 - 39 of 39 in total

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  1. Loh LC, Chan SK, Ch'ng KI, Tan LZ, Vijayasingham P, Thayaparan T
    Med J Malaysia, 2005 Oct;60(4):426-31.
    PMID: 16570703
    In the Malaysian setting of multi-ethnicity and high BCG coverage, interpretation of Tuberculin Skin Testing (TST) may be difficult. Between January 2001 and December 2003, a retrospective study on all adult patients with documented TST results treated for tuberculosis (TB) in chest clinics of two government hospitals was conducted to determine the reliability of TST and factors affecting its interpretation. One hundred and three patients [mean age (SD): 43 (17); male: 67%] were eligible for data collection: 72% and 57% of patients had positive TST results based on cut-off points of 10mm and 15mm respectively. The only significant univariate association with TST results was the severity of co-morbidity. A patient with co-morbidity score of 3 defined as those with any cancer, end-stage renal or liver disease, or HIV disease, was more likely to have a negative TST results [10mm cut-off point: Odd Ratio (95% CI) 6.6 (1.82 to 24.35), p = 0.003; 15mm cut-off point: 4.8 (1.21 to 18.95), p = 0.012]. A TST reading of 10mm had a higher sensitivity than 15mm as the cut-off point in diagnosing TB infection. Considering all possible confounding factors like ethnicity, prior BCG vaccination and TB burden in the population, severity of co-morbidity remains strongly predictive of a negative TST. Caution should be exercised in interpreting TST in these patients.
    Study site: Chest clinic, Hospital Seremban, Hospital Kuala Pilah, Negeri Sembilan, Malaysia
  2. Kho SS, Tie ST, Chan SK, Yong MC, Chai SL, Voon PJ
    Respirol Case Rep, 2017 May;5(3):e00221.
    PMID: 28250931 DOI: 10.1002/rcr2.221
    Chylothorax is defined as the presence of chyle in the pleural cavity. Central vein thrombosis is an under-recognized cause of chylothorax in the adult population and is commonly related to central venous catheterization. Case 1 illustrates a patient with AIDS and disseminated tuberculosis with left chylothorax and central vein thrombosis after a month of antituberculosis therapy. Case 2 was a patient with advanced seminoma who presented with left chylothorax and central vein thrombosis while on chemotherapy. Chylothorax resolved with anticoagulation for both cases. Case 3 was a lymphoma patient with central vein thrombosis who developed chylothorax during chemotherapy. Chylothorax resolved with the continuation of anticoagulation and did not recur despite his progressive underlying lymphoma. There was no central venous catheterization in any of these three cases. These cases illustrate the unique association of central vein thrombosis and chylothorax and the importance of anticoagulation in its management.
  3. Kho SS, Yong MC, Chan SK, Tie ST, Voon PJ
    Med J Malaysia, 2018 12;73(6):403-404.
    PMID: 30647213
    Malignant central airway obstruction (CAO) with ball valve effect (BVE) in the lung is rare. We discuss a case of metastatic colon cancer who presented with asthma like symptoms which thoracic computed tomography and bronchoscopy revealed an intraluminal tumour obstructing the left main bronchus in a ball valve manner. Airway patency was restored urgently with immediate alleviation of symptoms. This illustrates the importance of recognizing subtle features of central airway obstruction to allow expedition of appropriate investigations and therapy.
  4. Kho SS, Nyanti LE, Chai CS, Chan SK, Tie ST
    Clin Respir J, 2021 Jun;15(6):595-603.
    PMID: 33113256 DOI: 10.1111/crj.13297
    BACKGROUND: Although radial endobronchial ultrasound (rEBUS) is an important verification tool in guided bronchoscopy, a navigational route was not provided. Manual airway mapping allows the bronchoscopist to translate the bronchial branching in computed tomography (CT) into a comparable bronchoscopic road map. We aimed to explore the feasibility of this technique in navigating conventional rEBUS bronchoscopy in the localisation of peripheral pulmonary lesion by determining navigation success and diagnostic yield.

    METHODS: Retrospective review of consecutive rEBUS bronchoscopy performed with a 6.2 mm conventional bronchoscope navigated via manual bronchial branch reading technique over 18 months.

    RESULTS: Ninety-eight target lesions were included. Median lesion size was 2.67 cm (IQR 2.22-3.38) with 96.9% demonstrating positive CT bronchus sign. Majority (86.7%) of lesions were situated in between the third and fifth airway generations. Procedure was performed with endotracheal intubation in 43.9% and fluoroscopy in 72.4%. 98.9% of lesions were successfully navigated and verified by rEBUS following the pre-planned airway road map. Bidirectional guiding device was employed in 29.6% of cases. Clinical diagnosis was secured in 88.8% of cases, majority of which were malignant disease. The discrepancy between navigation success and diagnostic yield was 10.1%. Target PPL located within five airway generations was associated with better diagnostic yield (95.1% vs. 58.8%, P 

  5. Lim CC, Chan SK, Lim YY, Ishikawa Y, Choong YS, Nagaoka Y, et al.
    Mol Immunol, 2021 07;135:191-203.
    PMID: 33930714 DOI: 10.1016/j.molimm.2021.04.016
    The murine double minute 2 (MDM2) protein is a major negative regulator of the tumour suppressor protein p53. Under normal conditions, MDM2 constantly binds to p53 transactivation domain and/or ubiquinates p53 via its role as E3 ubiquitin ligase to promote p53 degradation as well as nuclear export to maintain p53 levels in cells. Meanwhile, amplification of MDM2 and appearance of MDM2 spliced variants occur in many tumours and normal tissues making it a prognostic indicator for human cancers. The mutation or deletion of p53 protein in half of human cancers inactivates its tumour suppressor activity. However, cancers with wild type p53 have its function effectively inhibited through direct interaction with MDM2 oncoprotein. Here, we described the construction of a MDM2 spliced variant (rMDM215kDa) consisting of SWIB/MDM2 domain and its central region for antibody generation. Biopanning with a human naïve scFv library generated four scFv clones specific to rMDM215kDa. Additionally, the selected scFv clones were able to bind to the recombinant full length MDM2 (rMDM2-FL). Computational prediction showed that the selected scFv clones potentially bind to exon 7-8 of MDM2 while leaving the MDM2/SWIB domain free for p53 interaction. The developed antibodies exhibit good specificity can be further investigated for downstream biomedical and research applications.
  6. Kho SS, Chan SK, Yong MC, Cheah HM, Lee YG, Tie ST
    Respir Investig, 2020 Sep;58(5):367-375.
    PMID: 32107195 DOI: 10.1016/j.resinv.2020.01.004
    BACKGROUND: Tuberculous pleural effusions (TBEs) and parapneumonic pleural effusion (PPEs) have similar clinical presentations and fluid biochemistry. A pleural biopsy is usually required to diagnose TBE but complete fluid evacuation may not be necessary, contrasting with complicated PPE (CPPE). A point-of-care test that distinguishes between TBE and CPPE enables the appropriate procedures to be performed during the initial diagnostic thoracentesis. Lactate is a metabolic product measurable by a blood-gas analyzer. This study measured pleural fluid (Pf) lactate levels in TBE and compared them with those in PPE/CPPE. We hypothesized that Pf lactate would be significantly higher in PPE because of active metabolic activities than in TBE which is driven by delayed hypersensitivity.

    METHODS: All patients undergoing an initial diagnostic thoracentesis over 18 months with Pf lactate measured using a calibrated point-of-care blood gas analyzer were assessed.

    RESULTS: The diagnoses of the enrolled patients (n = 170) included TBE (n = 49), PPE (n = 47), malignancy (n = 63), and transudate (n = 11). Pf lactate level in TBE, median 3.70 (inter-quartile range 2.65-4.90) mmol/l, was significantly lower than in PPE and CPPE. In the subgroup of TBE and CPPE patients whose initial Pf pH and glucose could suggest either condition, Pf lactate was significantly higher in those with CPPE. Pf lactate (cutoff ≥7.25 mmol/l) had a sensitivity of 79.3%, specificity 100%, positive predictive value 100%, and negative predictive value 89.1% for discriminating CPPE from TBE (area under the curve 0.947, p 

  7. Ngu NH, Chai CS, Chan SK, Kho SS, Yong MC, Tie ST
    Med J Malaysia, 2022 Nov;77(6):650-654.
    PMID: 36448380
    INTRODUCTION: Corticosteroids, particularly methylprednisolone, are part of the treatment for severe COVID-19 with acute respiratory distress syndrome (ARDS). In this study, we aimed to compare the mortalities of patients treated with higher versus lower doses of methylprednisolone. Secondary outcomes included oxygenation, need for mechanical ventilation, length of stay in intensive care unit (ICU), secondary infection, improvement of PaO2/FiO2 (PF) ratio, and inflammatory response as expressed by C-reactive protein (CRP).

    MATERIALS AND METHODS: A retrospective cohort study conducted at Sarawak General Hospital from 1st June to 30th September 2021. Patients who received intravenous methylprednisolone for severe COVID-19 in the ICU were identified and divided into two groups: higher dose (cumulative dose more than 10 mg per kg) and lower dose (cumulative dose less than 10 mg per kg).

    RESULTS: Out of a total of 165 patients, 40 (24.2%) patients received higher dose methylprednisolone. There was no significant difference in socio-demographic characteristics (age, gender, body mass index), COVID-19 vaccination status, laboratory parameters (lymphocyte count, CRP, lactate dehydrogenase, D-dimer), or usage of immunomodulator therapy between the groups. Overall mortality was 23.6%. Mortality in the higher dose group was twice as high compared to lower dose group (37.5% versus 19.2%) (OR 3.79, 95% CI 1.24-11.59, p<0.05). In addition, the higher dose cohort developed more secondary infections (87.5%) and had longer stays in ICU (median 11 days, IQR 8- 15). No significant difference was found between both cohorts in terms of CRP reduction, improvement of PF ratio, or the need for mechanical ventilation post methylprednisolone.

    CONCLUSION: In this study, the use of higher dose methylprednisolone in COVID-19 with ARDS was not associated with better clinical outcomes. A lower dose of methylprednisolone might be sufficient in treating severe COVID-19 with ARDS.

  8. Ida J, Chan SK, Glökler J, Lim YY, Choong YS, Lim TS
    Molecules, 2019 Mar 19;24(6).
    PMID: 30893817 DOI: 10.3390/molecules24061079
    G-quadruplexes are made up of guanine-rich RNA and DNA sequences capable of forming noncanonical nucleic acid secondary structures. The base-specific sterical configuration of G-quadruplexes allows the stacked G-tetrads to bind certain planar molecules like hemin (iron (III)-protoporphyrin IX) to regulate enzymatic-like functions such as peroxidase-mimicking activity, hence the use of the term DNAzyme/RNAzyme. This ability has been widely touted as a suitable substitute to conventional enzymatic reporter systems in diagnostics. This review will provide a brief overview of the G-quadruplex architecture as well as the many forms of reporter systems ranging from absorbance to luminescence readouts in various platforms. Furthermore, some challenges and improvements that have been introduced to improve the application of G-quadruplex in diagnostics will be highlighted. As the field of diagnostics has evolved to apply different detection systems, the need for alternative reporter systems such as G-quadruplexes is also paramount.
  9. Chai CS, Chan SK, Kho SS, Ahmad A, Tie ST
    J Bronchology Interv Pulmonol, 2023 Jul 01;30(3):285-288.
    PMID: 37101325 DOI: 10.1097/LBR.0000000000000922
  10. Kho SS, Chai CS, Ho RL, Yong MC, Chan SK, Tie ST
    J Bronchology Interv Pulmonol, 2024 Jan 01;31(1):90-92.
    PMID: 37735753 DOI: 10.1097/LBR.0000000000000946
  11. Chai CS, Chan SK, Kho SS, Yong MC, Tie ST
    Respirol Case Rep, 2020 Jul;8(5):e00562.
    PMID: 32313656 DOI: 10.1002/rcr2.562
    Bronchopleural fistula (BPF) can complicate necrotizing pneumonia. Surgery would be indicated in patients who fail conservative management, yet this group is often of poor pulmonary function and general condition. Bronchial occlusion with endobronchial Watanabe spigots (EWS) can be a potential alternative treatment when the culprit bronchi can be isolated. In this case report, we describe a middle-aged gentleman who presented with necrotizing pneumonia complicated with pyopneumothorax with right upper lobe BPF, and who had failed to respond to chest drainage and antibiotics. EWS bronchial occlusion finally led to cessation of air leak, allowing removal of chest tube. EWS were removed uneventfully six months later. This case highlights the role of EWS in the management of BPF in patients with high surgical risk.
  12. Oh AL, Makmor-Bakry M, Islahudin F, Ting CY, Chan SK, Tie ST
    Trop Med Int Health, 2024 May;29(5):434-445.
    PMID: 38470004 DOI: 10.1111/tmi.13987
    OBJECTIVES: Treatment interruption is associated with poor tuberculosis (TB) treatment outcomes and increased drug resistance. To address the issue, we aimed to investigate the characteristics, predictors and consequences of treatment interruption.

    METHODS: We conducted a retrospective cohort study by retrieving 4 years (2018-2021) of TB patients' records at 10 public health clinics in Sarawak, Malaysia. Adult patients (≥18 years) with drug-susceptible TB were selected. Treatment interruption was defined as ≥2 weeks of cumulative interruption during treatment. The Chi-square test, Mann-Whitney U test, Kaplan-Meier and Cox proportional hazards regression were used to analyse the data, with p 

  13. Chai CS, Kho SS, Chan SK, Tee TT, Tie ST
    Clin Med (Lond), 2021 Jan;21(1):e114-e115.
    PMID: 33479093 DOI: 10.7861/clinmed.2020-0913
    Percutaneous vertebroplasty (PV) involves injection of polymethylmethacrylate bone cement into vertebral body for relief of pain and strengthening of bone in symptomatic vertebral compression fractures.Passage of bone cement into vertebral venous plexus and then into the lungs is a rare and serious complication of PV. The reported incidence up to 26%.We present an incidental finding of pulmonary cement embolism (PCE) after PV. A 68-year-old woman with history of PV 3 years previously for T11 osteoporotic fracture presented to us with cough for 3 weeks following choking on a fish bone.Chest X-ray showed left lower zone consolidation and a high-density opacity in a tubular branching pattern, corresponding to pulmonary arterial distribution. Contrasted computed tomography of the thorax showed segmental pulmonary cement embolism of both lungs and left lower lobe consolidation.She underwent bronchoscopy with findings of a purulent secretion from the left lower lobe. Her symptoms resolved after 2 weeks of antibiotics. She was managed conservatively for the PCE as she remained asymptomatic.This case highlights the need for a standard post-PV chest X-ray, as patients with cement embolisms can be completely asymptomatic. Measures to minimise the risk of pulmonary cement embolisms during PV need to be taken.
  14. Chevillotte T, Chan SK, Grobost P, Laouissat F, Darnis A, Silvestre C, et al.
    Global Spine J, 2024 May;14(4):1110-1115.
    PMID: 36207768 DOI: 10.1177/21925682221133748
    STUDY DESIGN: Data collection of radiological parameters in non-pathological adult spines.

    OBJECTIVES: Establishing a baseline database for measurements of the spinal lordosis ratio between upper and lower arcs of the lumbar spine unique to each type of spine described by Roussouly's classification. Illustrating the importance of correct rationing of the upper and lower arcs.

    METHODS: Standardised standing true lateral plain radiographs of the spine (including base of skull and proximal femurs) from 373 adult volunteers were obtained. Exclusion criteria : any history of disease involving the spine, pelvis, hips or lower limbs. Incidental detection of any spinal deformity on radiography also excluded further participation in this study. Sacro-pelvic parameters data collected : Pelvic Incidence (PI), Pelvic Tilt (PT), Sacral Slope (SS), location of Inflection Point, number of vertebras in the spinal lordosis and type of Roussouly's spine. Values of upper arc, lower arc and spinal lordosis ratio (SLR) was determined.

    RESULTS: Bivariate analysis revealed statistically significant (P < .0001) correlation between the types of sagittal spinal alignments based on Roussouly's classification and the SLR. Type 1: SLR .76 ± .17, Type 2: SLR .60 ± .18, Type 3 with anteverted pelvis: SLR .53 ± .11, Type 3: SLR .49 ± .12, Type4: SLR .41 ± .11.

    CONCLUSION: With this data we are able to quantify the ratio of lumbar lordosis unique to each type of Roussouly's spine. It functions as a guide when planning lumbar spine surgeries in order to restore the SLR correctly and thus prevent post-op complications such as proximal junction kyphosis.

  15. Oh AL, Makmor-Bakry M, Islahudin F, Ting CY, Chan SK, Tie ST
    Res Social Adm Pharm, 2024 Dec;20(12 Pt A):1102-1109.
    PMID: 39218734 DOI: 10.1016/j.sapharm.2024.08.091
    BACKGROUND: Tuberculosis (TB) treatment interruption poses risks of antimicrobial resistance, potentially leading to treatment failure and mortality. Addressing the risk of early treatment interruption is crucial in tuberculosis care and management to improve treatment outcomes and curb disease transmission.

    OBJECTIVES: This study aimed to identify risk factors of TB treatment interruption and construct a predictive scoring model that enables objective risk stratification for better prediction of treatment interruption.

    METHODS: A multicentre retrospective cohort study was conducted at public health clinics in Sarawak, Malaysia over 11 months from March 2022 to January 2023, involving adult patients aged ≥18 years with drug-susceptible TB diagnosed between 2018 and 2021. Cumulative missed doses or discontinuation of TB medications for ≥2 weeks, either consecutive or non-consecutive, was considered as treatment interruption. The model was developed and internally validated using the split-sample method. Multiple logistic regression analysed 18 pre-defined variables to identify the predictors of TB treatment interruption. The Hosmer-Lemeshow test and area under the receiver operating characteristic curve (AUC) were employed to evaluate model performance.

    RESULTS: Of 2953 cases, two-thirds (1969) were assigned to the derivation cohort, and one-third (984) formed the validation cohort. Positive predictors included smoking, previously treated cases, and adverse drug reactions, while concurrent diabetes was protective. Based on the validation dataset, the model demonstrated good calibration (P = 0.143) with acceptable discriminative ability (AUC = 0.775). A cutoff score of 2.5 out of 11 achieved a sensitivity of 81 % and a specificity of 64.4 %. Risk stratification into low (0-2), medium (3-5), and high-risk (≥6) categories showed ascending interruption rates of 5.3 %, 18.1 %, and 41.3 %, respectively (P 

  16. Oh AL, Makmor-Bakry M, Islahudin F, Ting CY, Chan SK, Tie ST
    Health Promot Int, 2024 Dec 01;39(6).
    PMID: 39584467 DOI: 10.1093/heapro/daae176
    Tuberculosis (TB) treatment interruption undermines the effectiveness of TB medications and jeopardizes treatment outcomes. This study aimed to explore barriers, challenges, coping strategies and facilitators of TB treatment interruption to understand the treatment pathway in achieving successful outcomes. In-depth interviews were conducted at public health clinics in Sarawak, Malaysia, utilizing a phenomenological approach. Thirty patients who experienced TB treatment interruption with eventual successful treatment were purposively selected based on various reasons for treatment interruption to obtain diverse viewpoints. The audio-recorded transcriptions underwent thematic and content analysis. Five major themes emerged under barriers and challenges: socioeconomic, patient, therapy, healthcare and condition-related factors. Notably, financial burdens led individuals to prioritize work over health. Adverse drug reactions resulted in inappropriate self-medication and healthcare dissatisfaction. Medication error with suboptimal dosing was another facet leading to treatment forfeiture. Lack of knowledge about treatment duration and medication adherence, along with negative personal factors such as laziness, dishonesty and forgetfulness were reported. Participants employed coping strategies to confront barriers and challenges, including acceptance and commitment to disease and treatment, self-adaptation in mental, physical and social aspects, and self-management of minor adverse events. Fear of disease worsening, previous experiences, social and financial supports, along with intrinsic motivators, were essential facilitators that prevented interruptions. Interconnectivity across the explored dimensions contextualized the understanding of TB treatment interruption and offered valuable information for designing patient-centered intervention strategies. Improving patient education coupled with tailored interventions addressing psychosocial and economic barriers is crucial for ensuring TB treatment completion.
  17. Chin KL, Suing EJ, Andong R, Foo CH, Chan SK, Jani J, et al.
    Data Brief, 2024 Jun;54:110476.
    PMID: 38725551 DOI: 10.1016/j.dib.2024.110476
    Spinal tuberculosis, also referred to as Pott's disease, presents a significant risk of severe paralysis if not promptly detected and treated, owing to complications such as spinal cord compression and deformity. This article presents the genetic analysis of a Mycobacterium tuberculosis STB-T1A strain, isolated from the spine of a 29-year-old female diagnosed with spinal tuberculosis. Genomic DNA was extracted from pure culture and subjected to sequencing using the Illumina NovaSeq 6000 sequencing system. The genome of the M. tuberculosis STB-T1A strain spans 4,367,616 base pairs with a G+C content of 65.56 % and 4174 protein-coding genes. Comparative genomic analysis, conducted via single nucleotide polymorphism (SNP)-based phylogenetic analysis using the Maximum Likelihood method, revealed that the strain falls within the Indo-Oceanic lineage (Lineage 1). It clusters with the M. tuberculosis 43-16836 strain, which was isolated from the cerebrospinal fluid of a patient with tuberculous meningitis in Thailand. The complete genome sequence has been deposited at the National Center for Biotechnology Information (NCBI) GenBank database with the accession number JBBMVZ000000000.
  18. Ban AY, Vengadasalam P, Taher SW, Mohd Zim MA, Sirol Aflah SS, Daut UN, et al.
    PMID: 37292227 DOI: 10.51866/oa.258
    INTRODUCTION: SABINA III assessed short-acting β2-agonist (SABA) prescription patterns and their association with asthma-related outcomes globally. Herein, we examined SABA prescription and clinical outcomes in the Malaysian cohort of SABINA III.

    METHOD: In this observational, cross-sectional study, patients (≥12 years) were recruited between July and December 2019 from 15 primary and specialty care centres in Malaysia. Prescribed asthma treatments and severe exacerbation history within 12 months prior and asthma symptom control during the study visit were evaluated. Associations of SABA prescription with asthma control and severe exacerbation were analysed using multivariable regression models.

    RESULTS: Seven hundred thirty-one patients (primary care, n=265 [36.3%]; specialty care, n=466 [63.7%]) were evaluated. The prevalence of SABA over-prescription (≥3 SABA prescriptions/year) was 47.4% (primary care, 47.1%; specialty care, 47.6%), 51.8% and 44.5% among all patients and patients with mild and moderate-to-severe asthma, respectively. Altogether 9.0% (n=66) purchased SABA without a prescription; among them, 43.9% (n=29) purchased ≥3 inhalers. The mean (standard deviation) number of severe asthma exacerbations was 1.38 (2.76), and 19.7% (n=144) and 25.7% (n=188) had uncontrolled and partly controlled symptoms, respectively. Prescriptions of ≥3 SABA inhalers (vs 1-2) were associated with lower odds of at least partly controlled asthma (odds ratio=0.42; 95% confidence interval [CI]=0.27-0.67) and higher odds of having severe exacerbation(s) (odds ratio=2.04; 95% CI=1.44-2.89).

    CONCLUSION: The prevalence of SABA over-prescription in Malaysia is high, regardless of the prescriber type, emphasising the need for healthcare providers and policymakers to adopt latest evidence-based recommendations to address this public health concern.

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