MyMedR

Displaying publications 1 - 20 of 39 in total

Abstract:

Sort:

Molecular defense response of oil palm to Ganoderma infection

Ho CL, Tan YC

Phytochemistry, 2015 Jun;114:168-77.
PMID: 25457484 DOI: 10.1016/j.phytochem.2014.10.016

Basal stem rot (BSR) of oil palm roots is due to the invasion of fungal mycelia of Ganoderma species which spreads to the bole of the stem. In addition to root contact, BSR can also spread by airborne basidiospores. These fungi are able to break down cell wall components including lignin. BSR not only decreases oil yield, it also causes the stands to collapse thus causing severe economic loss to the oil palm industry. The transmission and mode of action of Ganoderma, its interactions with oil palm as a hemibiotroph, and the molecular defence responses of oil palm to the infection of Ganoderma boninense in BSR are reviewed, based on the transcript profiles of infected oil palms. The knowledge gaps that need to be filled in oil palm-Ganoderma molecular interactions i.e. the associations of hypersensitive reaction (HR)-induced cell death and reactive oxygen species (ROS) kinetics to the susceptibility of oil palm to Ganoderma spp., the interactions of phytohormones (salicylate, jasmonate and ethylene) at early and late stages of BSR, and cell wall strengthening through increased production of guaiacyl (G)-type lignin, are also discussed.
Expression profiles of defence related cDNAs in oil palm (Elaeis guineensis Jacq.) inoculated with mycorrhizae and Trichoderma harzianum Rifai T32

Tan YC, Wong MY, Ho CL

Plant Physiol Biochem, 2015 Nov;96:296-300.
PMID: 26322853 DOI: 10.1016/j.plaphy.2015.08.014

Basal stem rot is one of the major diseases of oil palm (Elaies guineensis Jacq.) caused by pathogenic Ganoderma species. Trichoderma and mycorrhizae were proposed to be able to reduce the disease severity. However, their roles in improving oil palm defence system by possibly inducing defence-related genes in the host are not well characterized. To better understand that, transcript profiles of eleven putative defence-related cDNAs in the roots of oil palm inoculated with Trichoderma harzianum T32 and mycorrhizae at different time points were studied. Transcripts encoding putative Bowman-Birk protease inhibitor (EgBBI2) and defensin (EgDFS) increased more than 2 fold in mycorrhizae-treated roots at 6 weeks post inoculation (wpi) compared to those in controls. Transcripts encoding putative dehydrin (EgDHN), glycine-rich RNA binding protein (EgGRRBP), isoflavone reductase (EgIFR), type 2 ribosome inactivating protein (EgT2RIP), and EgDFS increased in the oil palm roots treated with T. harzianum at 6 and/or 12 wpi compared to those in the controls. Some of these genes were also expressed in oil palm roots treated with Ganoderma boninense. This study provides an insight of some defence-related genes induced by Trichoderma and mycorrhizae, and their roles as potential agents to boost the plant defence system.
Fulltext A Systematic Stereo Camera Calibration Strategy: Leveraging Latin Hypercube Sampling and 2k Full-Factorial Design of Experiment Methods

Hao Y, Tai VC, Tan YC

Sensors (Basel), 2023 Oct 03;23(19).
PMID: 37837069 DOI: 10.3390/s23198240

This research aimed to optimize the camera calibration process by identifying the optimal distance and angle for capturing checkered board images, with a specific focus on understanding the factors that influence the reprojection error (ϵRP). The objective was to improve calibration efficiency by exploring the impacts of distance and orientation factors and the feasibility of independently manipulating these factors. The study employed Zhang's camera calibration method, along with the 2k full-factorial analysis method and the Latin Hypercube Sampling (LHS) method, to identify the optimal calibration parameters. Three calibration methods were devised: calibration with distance factors (D, H, V), orientation factors (R, P, Y), and the combined two influential factors from both sets of factors. The calibration study was carried out with three different stereo cameras. The results indicate that D is the most influential factor, while H and V are nearly equally influential for method A; P and R are the two most influential orientation factors for method B. Compared to Zhang's method alone, on average, methods A, B, and C reduce ϵRP by 25%, 24%, and 34%, respectively. However, method C requires about 10% more calibration images than methods A and B combined. For applications where lower value of ϵRP is required, method C is recommended. This study provides valuable insights into the factors affecting ϵRP in calibration processes. The proposed methods can be used to improve the calibration accuracy for stereo cameras for the applications in object detection and ranging. The findings expand our understanding of camera calibration, particularly the influence of distance and orientation factors, making significant contributions to camera calibration procedures.
Fulltext Bilateral subtentorial empyema complicated with nosocomial acinectobacter ventriculitis: a case report

Sim SK, Ch'ng CH, Tan YC, Kandasamy R, Abdullah JM

Med J Malaysia, 2014 Apr;69(2):86-8.
PMID: 25241818 MyJurnal

Subtentorial subdural empyema is a rare and life threatening intracranial suppuration. It is usually an intracranial complication of otogenic infections. Early diagnosis and surgical drainage are the most important factors determining prognosis. The high mortality reported in the literature reflects the severity of subtentorial subdural empyema if proper management is delayed. Intracranial infections usually require between 4 to 6 weeks of intravenous antibiotics therapy. However, the prolonged duration of hospitalization as well as requirement for neurosurgically inserted indwelling devices may predispose these patients to new nosocomial infections.
A preliminary study of using active vision guided robotic arm for bone drilling in a developing country

Abdullah MZ, Awang MS, Tan YC, Abdullah JM

J Neurol Surg A Cent Eur Neurosurg, 2014 Mar;75(2):155-7.
PMID: 23636911 DOI: 10.1055/s-0032-1330954

The study assesses the capability and accuracy of a robotic arm to perform burr holes.
Fulltext Brain metastasis of atrial myxoma: Case report

Badrisyah I, Saiful R, Rahmat H, Naik VR, Tan YC

Med J Malaysia, 2012 Dec;67(6):613-5.
PMID: 23770956 MyJurnal

Metastasis of an atrial myxoma to the brain is extremely rare. Thus far there are only 17 cases reported, including our present case. Most of the brain metastases manifest only in 3 to 6 decades, after an average time frame of one to two years after surgical removal of parental tumour. We present a case of brain metastases of atrial myxoma in a teenager of the youngest age among all reported cases, unusually as early as 15 years old. The progress of the metastatic process had been insidious for three years after heart surgery, The imaging demonstrated a rather sizeable tumour by the time when the patient is symptomatic. The location of the metastatic tumour is anyhow superficial to the cortical surface, enabling complete surgical excision of the tumour easily achievable with favourable outcome.
Cerebral venous sinus thrombosis: review of cases in a single centre in Malaysia

Sim SK, Tan YC, Ghani ARI

Med J Malaysia, 2020 01;75(1):38-42.
PMID: 32008018

INTRODUCTION: Cerebral venous sinus thrombosis (CVST) is a potentially fatal neurological condition. However, due to the non-specific clinical and radiological features of CVST, it can sometimes result in a delay in the diagnosis and subsequent management. The aim of this study was to evaluate the demography, risk factors and one-year outcome of CVST patients treated in Hospital Universiti Sains Malaysia.
METHODS: In this retrospective study, we reviewed the cases diagnosed with CVST admitted to our centre from January 2011 until November 2015.
RESULTS: A total of 15 patients were included in this review. The patterns of imaging findings as well as risk factors for CVST is discussed with a review of the literature and current management practices. One year followed-up showed full recovery (Glasgow Outcome Scale (GOS) of 5) in 10 cases (66.7%), whereas 4 cases (26.7%) with GOS of 4 (three cases with neurological deficits, and 1 case with mild symptom. There was one case of mortality in this study secondary to sepsis during hospitalisation. The presenting symptoms were mainly headache, focal neurology deficits, seizure and altered sensorium. Risk factors identified were oral contraceptive pills usage, chronic sinuses or ear infections, and obesity. Initial computed tomography (CT) scan showed various findings and haemorrhagic infarct was one of the common findings. Magnetic resonance imaging (MRI) and magnetic resonance venography (MRV) revealed majority of the patients had occlusion at two or more venous sinus sites. No patients had new or recurrent intracranial haemorrhage following initiation of anticoagulation therapy.
CONCLUSION: Thus it is considerable safe to start anticoagulation therapy in CVST patients including those with intracranial haemorrhage. We propose further neuroimaging to avoid missed diagnosis of CVST in patient presented with recent onset headache and CT evidence of unusual cerebral infarction.
Fulltext Metabolite Profiling of Malaysian Gracilaria edulis Reveals Eplerenone as Novel Antibacterial Compound for Drug Repurposing Against MDR Bacteria

Asghar A, Tan YC, Shahid M, Yow YY, Lahiri C

Front Microbiol, 2021;12:653562.
PMID: 34276590 DOI: 10.3389/fmicb.2021.653562

With a continuous threat of antimicrobial resistance on human health worldwide, efforts for new alternatives are ongoing for the management of bacterial infectious diseases. Natural products of land and sea, being conceived to be having fewer side effects, pose themselves as a welcome relief. In this respect, we have taken a scaffolded approach to unearthing the almost unexplored chemical constituents of Malaysian red seaweed, Gracilaria edulis. Essentially, a preliminary evaluation of the ethyl acetate and acetone solvent extracts, among a series of six such, revealed potential antibacterial activity against six MDR species namely, Klebsiella pneumoniae, Pseudomonas aeruginosa, Salmonella enterica, methicillin-resistant Staphylococcus aureus (MRSA), Streptococcus pyogenes, and Bacillus subtilis. Detailed analyses of the inlying chemical constituents, through LC-MS and GC-MS chromatographic separation, revealed a library of metabolic compounds. These were led for further virtual screening against selected key role playing proteins in the virulence of the aforesaid bacteria. To this end, detailed predictive pharmacological analyses added up to reinforce Eplerenone as a natural alternative from the plethora of plausible bioactives. Our work adds the ongoing effort to re-discover and repurpose biochemical compounds to combat the antimicrobial resistance offered by the Gram-positive and the -negative bacterial species.
Oil Palm Defensin: A Thermal Stable Peptide that Restricts the Mycelial Growth of Ganoderma boninense

Tan YC, Ang CL, Wong MY, Ho CL

Protein Pept Lett, 2016;23(11):994-1002.
PMID: 27719656

Plant defensins are plant defence peptides that have many different biological activities, including antifungal, antimicrobial, and insecticidal activities. A cDNA (EgDFS) encoding defensin was isolated from Elaeis guineensis. The open reading frame of EgDFS contained 231 nucleotides encoding a 71-amino acid protein with a predicted molecular weight at 8.69 kDa, and a potential signal peptide. The eight highly conserved cysteine sites in plant defensins were also conserved in EgDFS. The EgDFS sequence lacking 30 amino acid residues at its N-terminus (EgDFSm) was cloned into Escherichia coli BL21 (DE3) pLysS and successfully expressed as a soluble recombinant protein. The recombinant EgDFSm was found to be a thermal stable peptide which demonstrated inhibitory activity against the growth of G. boninense possibly by inhibiting starch assimilation. The role of EgDFSm in oil palm defence system against the infection of pathogen G. boninense was discussed.
Fulltext ClicO FS: an interactive web-based service of Circos

Cheong WH, Tan YC, Yap SJ, Ng KP

Bioinformatics, 2015 Nov 15;31(22):3685-7.
PMID: 26227146 DOI: 10.1093/bioinformatics/btv433

: We present ClicO Free Service, an online web-service based on Circos, which provides a user-friendly, interactive web-based interface with configurable features to generate Circos circular plots.
Expression profiles of putative defence-related proteins in oil palm (Elaeis guineensis) colonized by Ganoderma boninense

Tan YC, Yeoh KA, Wong MY, Ho CL

J Plant Physiol, 2013 Nov 01;170(16):1455-60.
PMID: 23769496 DOI: 10.1016/j.jplph.2013.05.009

Basal stem rot (BSR) is a major disease of oil palm caused by a pathogenic fungus, Ganoderma boninense. However, the interaction between the host plant and its pathogen is not well characterized. To better understand the response of oil palm to G. boninense, transcript profiles of eleven putative defence-related genes from oil palm were measured by quantitative reverse-transcription (qRT)-PCR in the roots of oil palms treated with G. boninense from 3 to 12 weeks post infection (wpi). These transcripts encode putative Bowman-Birk serine protease inhibitors (EgBBI1 and 2), defensin (EgDFS), dehydrin (EgDHN), early methionine-labeled polypeptides (EgEMLP1 and 2), glycine-rich RNA binding protein (EgGRRBP), isoflavone reductase (EgIFR), metallothionein-like protein (EgMT), pathogenesis-related-1 protein (EgPRP), and type 2 ribosome-inactivating protein (EgT2RIP). The transcript abundance of EgBBI2 increased in G. boninense-treated roots at 3 and 6wpi compared to those of controls; while the transcript abundance of EgBBI1, EgDFS, EgEMLP1, EgMT, and EgT2RIP increased in G. boninense-treated roots at 6 or 12wpi. Meanwhile, the gene expression of EgDHN was up-regulated at all three time points in G. boninense-treated roots. The expression profiles of the eleven transcripts were also studied in leaf samples upon inoculation of G. boninense and Trichoderma harzianum to identify potential biomarkers for early detection of BSR. Two candidate genes (EgEMLP1 and EgMT) that have different profiles in G. boninense-treated leaves compared to those infected by T. harzianum may have the potential to be developed as biomarkers for early detection of G. boninense infection.
Fulltext Craniotomy Improves Traumatic Optic Neuropathy

Ejyj J, Ang WJ, Wh WH, Tan YC

Cureus, 2018 Jun 19;10(6):e2835.
PMID: 30131928 DOI: 10.7759/cureus.2835

Traumatic optic neuropathy (TON) is a rare devastating complication of traumatic head injury and is an ophthalmic emergency. Herein, we report a rare case of a 46-year-old gentleman who experienced severe blurring of vision, binocular diplopia, and pain over his left eye following a fall from a tree about three meters in height. Examinations revealed the visual acuity was 6/60 with a marked relative afferent pupillary defect and generalized ophthalmoplegia over his left eye. Emergency computed tomography (CT) brain and orbit showed a left frontotemporoparietal extradural hemorrhage, comminuted frontotemporoparietal and greater wing of sphenoid fracture with a bony spur impinging the lateral rectus and indirectly on the optic nerve. A diagnosis of left frontotemporoparietal bone fracture with traumatic optic neuropathy was made. An emergency left craniotomy, elevation of depressed skull fracture, and evacuation of clot was done. Postoperatively, his visual acuity showed marked improvement with visual acuity of 6/6 and all optic nerve functions were normal.
Fulltext A case report of atypical teratoid/rhabdoid tumour in a 9-year-old girl

Chan KH, Mohammed Haspani MS, Tan YC, Kassim F

Malays J Med Sci, 2011 Jul;18(3):82-6.
PMID: 22135607 MyJurnal

Primary central nervous system atypical rhabdoid/teratoid tumour (ATRT) is a rare and highly malignant tumour that tends to occur in infancy and early childhood. The majority of tumours (approximately two-third) arise in the posterior fossa. The optimal treatment for ATRT remains unclear. Options of treatment include surgery, radiotherapy, and chemotherapy. Each of their role is still not clearly defined until now. The prognosis of the disease is generally unfavourable. This is a case report of ATRT in an atypical site in a 9-year-old girl.
Transfrontal Transaqueductal, Transtrigonal, and Suboccipital Infratentorial Supracerebellar Endoscopic Fenestration of Posterior Fossa Arachnoid Cysts: Three Surgical Cases

Idris Z, Tan YC, Kandasamy R, Ghani RI, Abdullah JM

J Neurol Surg A Cent Eur Neurosurg, 2017 Mar;78(2):210-215.
PMID: 26968147 DOI: 10.1055/s-0035-1571161

Symptomatic intracranial arachnoid cysts are commonly treated using neuroendoscopy. Cysts located within the posterior fossa may present a greater surgical challenge to the neurosurgeon due to the numerous vital neurovascular structures located within this confined space. Adding neuronavigation during endoscopy helps a neurosurgeon to visualize and utilize both anterior and posterior corridors safely to access and manage these lesions. We present three symptomatic posterior fossa arachnoid cysts that were treated successfully using minimally invasive neuronavigation-guided endoscopic neurosurgery utilizing the anterior transfrontal transaqueductal, anterior transfrontal transtrigonal, and posterior suboccipital infratentorial supracerebellar approaches.
Fulltext De novo transcriptome analyses of host-fungal interactions in oil palm (Elaeis guineensis Jacq.)

Ho CL, Tan YC, Yeoh KA, Ghazali AK, Yee WY, Hoh CC

BMC Genomics, 2016;17:66.
PMID: 26781612 DOI: 10.1186/s12864-016-2368-0

Basal stem rot (BSR) is a fungal disease in oil palm (Elaeis guineensis Jacq.) which is caused by hemibiotrophic white rot fungi belonging to the Ganoderma genus. Molecular responses of oil palm to these pathogens are not well known although this information is crucial to strategize effective measures to eradicate BSR. In order to elucidate the molecular interactions between oil palm and G. boninense and its biocontrol fungus Trichoderma harzianum, we compared the root transcriptomes of untreated oil palm seedlings with those inoculated with G. boninense and T. harzianum, respectively.
Fulltext Paclitaxel Inhibits Expression of Neuronal Nitric Oxide Synthase and Prevents Mitochondrial Dysfunction in Spinal Ventral Horn in Rats After C7 Spinal Root Avulsion

Sim SK, Tan YC, Tee JH, Yusoff AA, Abdullah JM

Turk Neurosurg, 2015;25(4):617-24.
PMID: 26242340 DOI: 10.5137/1019-5149.JTN.14035-15.1

This study evaluated the neuroprotective effect of intrathecally infused paclitaxel in the prevention of motoneuron death and mitochondrial dysfunction following brachial plexus avulsion injury.
Fulltext Candidate Essential Genes in Burkholderia cenocepacia J2315 Identified by Genome-Wide TraDIS

Wong YC, Abd El Ghany M, Naeem R, Lee KW, Tan YC, Pain A, et al.

Front Microbiol, 2016;7:1288.
PMID: 27597847 DOI: 10.3389/fmicb.2016.01288

Burkholderia cenocepacia infection often leads to fatal cepacia syndrome in cystic fibrosis patients. However, antibiotic therapy rarely results in complete eradication of the pathogen due to its intrinsic resistance to many clinically available antibiotics. Recent attention has turned to the identification of essential genes as the proteins encoded by these genes may serve as potential targets for development of novel antimicrobials. In this study, we utilized TraDIS (Transposon Directed Insertion-site Sequencing) as a genome-wide screening tool to facilitate the identification of B. cenocepacia genes essential for its growth and viability. A transposon mutant pool consisting of approximately 500,000 mutants was successfully constructed, with more than 400,000 unique transposon insertion sites identified by computational analysis of TraDIS datasets. The saturated library allowed for the identification of 383 genes that were predicted to be essential in B. cenocepacia. We extended the application of TraDIS to identify conditionally essential genes required for in vitro growth and revealed an additional repertoire of 439 genes to be crucial for B. cenocepacia growth under nutrient-depleted conditions. The library of B. cenocepacia mutants can subsequently be subjected to various biologically related conditions to facilitate the discovery of genes involved in niche adaptation as well as pathogenicity and virulence.
Fulltext A scaffolded approach to unearth potential antibacterial components from epicarp of Malaysian Nephelium lappaceum L

Asghar A, Tan YC, Zahoor M, Zainal Abidin SA, Yow YY, Khan E, et al.

Sci Rep, 2021 Jul 05;11(1):13859.
PMID: 34226594 DOI: 10.1038/s41598-021-92622-0

The emergence and spread of antimicrobial resistance have been of serious concern to human health and the management of bacterial infectious diseases. Effective treatment of these diseases requires the development of novel therapeutics, preferably free of side effects. In this regard, natural products are frequently conceived to be potential alternative sources for novel antibacterial compounds. Herein, we have evaluated the antibacterial activity of the epicarp extracts of the Malaysian cultivar of yellow rambutan fruit (Nephelium lappaceum L.) against six pathogens namely, Bacillus subtilis, methicillin-resistant Staphylococcus aureus (MRSA), Streptococcus pyogenes, Pseudomonas aeruginosa, Klebsiella pneumoniae and Salmonella enterica. Among a series of solvent extracts, fractions of ethyl acetate and acetone have revealed significant activity towards all tested strains. Chemical profiling of these fractions, via HPLC, LC-MS and GC-MS, has generated a library of potentially bioactive compounds. Downstream virtual screening, pharmacological prediction, and receptor-ligand molecular dynamics simulation have eventually unveiled novel potential antibacterial compounds, which can be extracted for medicinal use. We report compounds like catechin, eplerenone and oritin-4-beta-ol to be computationally inhibiting the ATP-binding domain of the chaperone, DnaK of P. aeruginosa and MRSA. Thus, our work follows the objective to propose new antimicrobials capable of perforating the barrier of resistance posed by both the gram positives and the negatives.
Fulltext Risk Factors and Phenytoin Prophylaxis for Early Post-Traumatic Seizures among Patients with Traumatic Brain Injury

Chan KH, Tharakan J, Pal HK, Khan N, Tan YC

Malays J Med Sci, 2010 Oct;17(4):36-43.
PMID: 22135559

Post-traumatic seizure is a well-known and serious complication of traumatic brain injury (TBI). The incidence and risk factors vary among study populations. Very little data have been published concerning this in the Malaysian population. The aim of this study was to ascertain the risk factors for the development of early post-traumatic seizures among patients with TBI.
Fulltext Draft Genome Sequence of Ochroconis constricta UM 578, Isolated from Human Skin Scraping

Chan CL, Yew SM, Na SL, Tan YC, Lee KW, Yee WY, et al.

Genome Announc, 2014;2(2).
PMID: 24744321 DOI: 10.1128/genomeA.00074-14

Ochroconis constricta is a soilborne dematiaceous fungus that has never been reported to be associated with human infection. Here we report the first draft genome sequence of strain UM 578, isolated from human skin scraping. The genomic information revealed will contribute to a better understanding of this species.

Filters

Please provide feedback to Administrator (afdal@afpm.org.my)

External Links