Displaying publications 1 - 20 of 67 in total

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  1. Chen WS, Tan JH, Mohamad Y, Imran R
    Injury, 2019 May;50(5):1118-1124.
    PMID: 30591225 DOI: 10.1016/j.injury.2018.12.031
    BACKGROUND: The establishment of an accurate prognostic model in major trauma patients is important mainly because this group of patients will benefit the most. Clinical prediction models must be validated internally and externally on a regular basis to ensure the prediction is accurate and current. This study aims to externally validate two prediction models, the Trauma and Injury Severity Score model developed using the Major Trauma Outcome Study in North America (MTOS-TRISS model), and the NTrD-TRISS model, which is a refined MTOS-TRISS model with coefficients derived from the Malaysian National Trauma Database (NTrD), by regarding mortality as the outcome measurement.

    METHOD: This retrospective study included patients with major trauma injuries reported to a trauma centre of Hospital Sultanah Aminah over a 6-year period from 2011 and 2017. Model validation was examined using the measures of discrimination and calibration. Discrimination was assessed using the area under the receiver operating characteristic curve (AUC) and 95% confidence interval (CI). The Hosmer-Lemeshow (H-L) goodness-of-fit test was used to examine calibration capabilities. The predictive validity of both MTOS-TRISS and NTrD-TRISS models were further evaluated by incorporating parameters such as the New Injury Severity Scale and the Injury Severity Score.

    RESULTS: Total patients of 3788 (3434 blunt and 354 penetrating injuries) with average age of 37 years (standard deviation of 16 years) were included in this study. All MTOS-TRISS and NTrD-TRISS models examined in this study showed adequate discriminative ability with AUCs ranged from 0.86 to 0.89 for patients with blunt trauma mechanism and 0.89 to 0.99 for patients with penetrating trauma mechanism. The H-L goodness-of-fit test indicated the NTrD-TRISS model calibrated as good as the MTOS-TRISS model for patients with blunt trauma mechanism.

    CONCLUSION: For patients with blunt trauma mechanism, both the MTOS-TRISS and NTrD-TRISS models showed good discrimination and calibration performances. Discrimination performance for the NTrD-TRISS model was revealed to be as good as the MTOS-TRISS model specifically for patients with penetrating trauma mechanism. Overall, this validation study has ascertained the discrimination and calibration performances of the NTrD-TRISS model to be as good as the MTOS-TRISS model particularly for patients with blunt trauma mechanism.

  2. Tan JH, Lip H, Ong W, Omar S
    Malays Fam Physician, 2019;14(2):29-31.
    PMID: 31827733
    An Intrauterine contraceptive devices (IUCD) is commonly inserted by the primary health care physician. It can migrate into pelvic or abdominal organs. When a pregnancy occurs following an insertion of an IUCD, there should be a high suspicion of uterine perforation or possible migration. A radiograph can be done in the primary health care clinic to search for a missing IUCD. Early referral to the urology service is warranted when a patient presents with recurrent urinary tract infections. Removal of an intravesical IUCD can be managed with cystoscopy, laparoscopy or open surgery. Herein, we report a case of IUCD migration into the bladder. This case will highlight the importance of proper technique, careful insertion and the role of ultrasound.
  3. Ng ZQ, Tan JH, Tan H
    Malays Fam Physician, 2019;14(2):32-35.
    PMID: 31827734
    Caecal volvulus has been reported to be associated with various abdominal and pelvic pathologies. Its signs and symptoms are usually non-specific and maybe overlooked in favour of benign causes, such as constipation. A high degree of suspicion is required for prompt diagnosis. Herein, we report on an unusual case of caecal volvulus after a dental procedure that was managed initially as constipation.
  4. Ng ZQ, Tan HCL, Tan JH
    J Gastrointest Surg, 2023 Apr;27(4):836-837.
    PMID: 36658386 DOI: 10.1007/s11605-023-05597-w
  5. Tan JH, Liew KJ, Goh KM
    Data Brief, 2024 Oct;56:110829.
    PMID: 39252782 DOI: 10.1016/j.dib.2024.110829
    This data report presents prokaryotic metagenome-assembled genomes (MAGs) from a hot spring stream with temperatures between 64 and 100°C. The stream water was filtered and the extracted total DNA was sequenced using the Illumina HiSeq 2500 platform. Approximately 80 Gb of raw data were generated, which were subsequently assembled using MEGAHIT v1.2.9. The MAGs were generated using MetaWRAP with binning approaches of MetaBAT2, CONCOCT and MaxBin2. We constructed 25 medium-quality and 24 high-quality archaeal MAGs, and 152 medium-quality and 112 high-quality bacterial MAGs. The fasta files of these MAGs are available in the NCBI database as well as Mendeley Data. Major phyla identified include Bacteroidota, Chloroflexota, Desulfobacterota, Firmicutes, Patescibacteria, Proteobacteria, Spirochaetota, Verrucomicrobiota, Armatimonadota, Nitrospirota, Acidobacteriota, Elusimicrobiota, Planctomycetota, Candidate division WOR-3, Aquificota, Thermoproteota, and Micrarchaeota. This dataset is valuable for studies on thermophilic genomes, reconstruction of biochemical pathways and gene discovery.
  6. Perera J, Tan JH, Jeevathayaparan S, Chakravarthi S, Haleagrahara N
    Cell Biosci, 2011;1(1):12.
    PMID: 21711768 DOI: 10.1186/2045-3701-1-12
    Haloperidol is an antipsychotic drug that exerts its' antipsychotic effects by inhibiting dopaminergic neurons. Although the exact pathophysiology of haloperidol extrapyramidal symptoms are not known, the role of reactive oxygen species in inducing oxidative stress has been proposed as one of the mechanisms of prolonged haloperidol-induced neurotoxicity. In the present study, we evaluate the protective effect of alpha lipoic acid against haloperidol-induced oxidative stress in the rat brain. Sprague Dawley rats were divided into control, alpha lipoic acid alone (100 mg/kg p.o for 21 days), haloperidol alone (2 mg/kg i.p for 21 days), and haloperidol with alpha lipoic acid groups (for 21 days). Haloperidol treatment significantly decreased levels of the brain antioxidant enzymes super oxide dismutase and glutathione peroxidase and concurrent treatment with alpha lipoic acid significantly reversed the oxidative effects of haloperidol. Histopathological changes revealed significant haloperidol-induced damage in the cerebral cortex, internal capsule, and substantia nigra. Alpha lipoic acid significantly reduced this damage and there were very little neuronal atrophy. Areas of angiogenesis were also seen in the alpha lipoic acid-treated group. In conclusion, the study proves that alpha lipoic acid treatment significantly reduces haloperidol-induced neuronal damage.
  7. Tan JH, Tan HC, Loke SC, Arulanantham SA
    Nephrology (Carlton), 2017 Apr;22(4):308-315.
    PMID: 26952689 DOI: 10.1111/nep.12761
    AIM: Calcium infusion is used after parathyroid surgery for renal hyperparathyroidism to treat postoperative hypocalcaemia. We compared a new infusion regimen to one commonly used in Malaysia based on 2003 K/DOQI guidelines.

    METHODS: Retrospective data on serum calcium and infusion rates was collected from 2011-2015. The relationship between peak calcium efflux (PER) and time was determined using a scatterplot and linear regression. A comparison between regimens was made based on treatment efficacy (hypocalcaemia duration, total infusion amount and time) and calcium excursions (outside target range, peak and trough calcium) using bar charts and an unpaired t-test.

    RESULTS: Fifty-one and 34 patients on the original and new regimens respectively were included. Mean PER was lower (2.16 vs 2.56 mmol/h; P = 0.03) and occurred earlier (17.6 vs 23.2 h; P = 0.13) for the new regimen. Both scatterplot and regression showed a large correlation between PER and time (R-square 0.64, SE 1.53, P 

  8. Loong BJ, Tan JH, Lim KH, Mbaki Y, Ting KN
    Naunyn Schmiedebergs Arch Pharmacol, 2015 Oct;388(10):1061-7.
    PMID: 26051407 DOI: 10.1007/s00210-015-1140-3
    The functional responses of different overnight-stored in vitro tissues are not clearly described in any animal model. The influence of overnight storage in an animal model may vary between tissue types. We employed Sprague-Dawley rat as our animal model and investigated the functional changes of rat aorta, trachea, bronchus and bladder that were used (i) immediately after surgical removal (denoted as fresh) and (ii) after storage in aerated (95% O2, 5% CO2) Krebs-Ringer bicarbonate solution at 4 °C for 24 h (denoted as stored). The aorta ring was pre-contracted with phenylephrine, and the functional response of the tissue was investigated using isoprenaline, forskolin and carbachol. Carbachol was also used to increase the tone in trachea, bronchus rings and bladder strips. A clear reduced function of endothelium, with a minor if any effect in the smooth muscle function in rat aorta was observed after overnight storage. The contractile response of overnight-stored rat airway (trachea and bronchus) and bladder smooth muscles remained unchanged. Among all tested tissues, only bronchus showed a reduced response rate (only 40% responded) after storage. In vitro rat tissues that are stored in Krebs solution at 4 °C for 24 h can still be used to investigate smooth muscle responses, however, not endothelium-mediated responses for aorta. The influence of overnight storage on different tissues from an animal model (Sprague-Dawley rat in our study) also provides an insight in maximising the use of sacrificed animals.
  9. Ng ZQ, Tan JH, Tan HCL, Theophilus M
    World J Gastrointest Endosc, 2021 Mar 16;13(3):82-89.
    PMID: 33763188 DOI: 10.4253/wjge.v13.i3.82
    BACKGROUND: Post-colonoscopy diverticulitis is increasingly recognized as a potential complication. However, the evidence is sparse in the literature.

    AIM: To systematically review all available evidence to describe the incidence, clinical course with management and propose a definition.

    METHODS: The databases PubMed, EMBASE and Cochrane databases were searched using with the keywords up to June 2020. Additional manual search was performed and cross-checked for additional references. Data collected included demographics, reason for colonoscopy, time to diagnosis, method of diagnosis (clinical vs imaging) and management outcomes.

    RESULTS: A total of nine studies were included in the final systematic review with a total of 339 cases. The time to diagnosis post-colonoscopy ranged from 2 h to 30 d. Clinical presentation for these patients were non-specific including abdominal pain, nausea/vomiting, per rectal bleeding and chills/fever. Majority of the cases were diagnosed based on computed tomography scan. The management for these patients were similar to the usual patients presenting with diverticulitis where most resolve with non-operative intervention (i.e., antibiotics and bowel rest).

    CONCLUSION: The entity of post-colonoscopy diverticulitis remains contentious where there is a wide duration post-procedure included. Regardless of whether this is a true complication post-colonoscopy or a de novo event, early diagnosis is vital to guide appropriate treatment. Further prospective studies especially registries should include this as a complication to try to capture the true incidence.

  10. 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.

  11. Pang WS, Tan JH, Tan HCL, Tan JKG
    Malays Fam Physician, 2021 Jul 22;16(2):78-82.
    PMID: 34386169 DOI: 10.51866/cr1087
    Retained rectal foreign body, with its associated social stigma, is a medical condition that is infrequently reported in Malaysia. We report the surgical management of five cases of retained foreign objects in the rectum seen over a one-year period. There were three young and two elderly male patients. One of the elderly patients presented with altered bowel habits and an abdominal mass that mimicked a symptomatic colonic tumor. All patients had an abdominal radiograph which clinched the diagnosis of a retained foreign rectal body. Successfully retrieved objects included two bottles, one bidet device, and two sex toys. Open surgery for retrieval of the impacted rectal foreign body was required in one patient. All underwent successful retrievals without any adverse postoperative complications. In our case series, retained rectal foreign bodies were observed only in the male gender. The age presentation was bimodal, with age groups in the twenties and sixties. The treatment options used for the retrieval of these impacted foreign bodies included transanal extraction or explorative laparotomy. Proximal migration and delayed presentation are possible indications for the latter approach.
  12. Pang YL, Tan JH, Lim S, Chong WC
    Polymers (Basel), 2021 Sep 06;13(17).
    PMID: 34503049 DOI: 10.3390/polym13173009
    Chitosan is a second-most abundant biopolymer on earth after cellulose. Its unique properties have recently received particular attention from researchers to be used as a potential biosorbent for the removal of organic dyes. However, pure chitosan has some limitations that exhibit lower biosorption capacity, surface area and thermal stability than chitosan composites. The reinforcement materials used for the synthesis of chitosan composites were carbon-based materials, metal oxides and other biopolymers. This paper reviews the effects of several factors such as pH, biosorbent dosage, initial dye concentration, contact time and temperature when utilizing chitosan-based materials as biosorbent for removing of organic dyes from contaminated water. The behaviour of the biosorption process for various chitosan composites was compared and analysed through the kinetic models, isotherm models and thermodynamic parameters. The findings revealed that pseudo-second-order (PSO) and Langmuir isotherm models were best suited for describing most of the biosorption processes or organic dyes. This indicated that monolayer chemisorption of organic dyes occurred on the surface of chitosan composites. Most of the biosorption processes were endothermic, feasible and spontaneous at the low temperature range between 288 K and 320 K. Therefore, chitosan composites were proven to be a promising biosorbent for the removal of organic dyes.
  13. Tan JH, Ng ZQ, Tan HCL, Vendargon S
    BMJ Case Rep, 2018 Jun 27;2018.
    PMID: 29950501 DOI: 10.1136/bcr-2018-224741
    A 72-year-old Chinese man presented with mild symptoms of heart failure. Transthoracic echocardiography showed signs of cardiac tamponade though clinically he was relatively well. The option of pericardiocentesis was not carried out due to a narrow window for aspiration with only a thin layer of effusion seen surrounding the apex and right ventricle on subcostal view.Pericardial window was done via a left anterolateral thoracotomy. Intraoperatively, 500 cm3 of purulent fluid was drained. Microbiology screens were all negative. We present the atypical clinical course of this elderly man presenting with a large pyopericardium.
  14. Tan JH, Ding HX, Fong MY, Lau YL
    Infect Genet Evol, 2023 Oct;114:105490.
    PMID: 37595939 DOI: 10.1016/j.meegid.2023.105490
    Plasmodium knowlesi is the leading cause of malaria in Malaysia. Serine Repeat Antigens (SERAs) have an essential role in the parasite life cycle. However, genetic characterization on P. knowlesi SERA3 Ag2 (PkSERA3 Ag2) is lacking. In the present study, nucleotide diversity, natural selection, and haplotypes of PkSERA3 Ag2 in clinical samples from Peninsular Malaysia and Malaysian Borneo were investigated. A total of 50 P. knowlesi clinical samples were collected from Peninsular Malaysia and Malaysian Borneo. The PkSERA3 Ag2 gene was amplified using PCR, and subsequently cloned and sequenced. Genetic diversity, haplotype, natural selection as well as genetic structure and differentiation of PkSERA3 Ag2 were analysed. In addition, in silico analyses were performed to identify repeat motifs, B-cell epitopes, and antigenicity indices of the protein. Analysis of 114 PkSERA3 Ag2 sequences revealed high nucleotide diversity of the gene in Malaysia. A codon-based Z-test indicated that the gene underwent purifying selection. Haplotype and population structure analyses identified two distinct PkSERA3 Ag2 clusters (K = 2, ΔK = 721.14) but no clear genetic distinction between PkSERA3 Ag2 from Peninsular Malaysia and Malaysian Borneo. FST index indicated moderate differentiation of the gene. In silico analyses revealed unique repeat motifs among PkSERA3 Ag2 isolates. Moreover, the amino acid sequence of PkSERA3 Ag2 exhibited potential B-cell epitopes and possessed high antigenicity indices. These findings enhance the understanding of PkSERA3 Ag2 gene as well as its antigenic properties. Further validation is necessary to ascertain the utility of PkSERA3 Ag2 as a serological marker for P. knowlesi infection.
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