Displaying publications 1 - 20 of 25 in total

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  1. Heng SP, Low SH, Sivamany K
    Indian J Cancer, 2015 Oct-Dec;52(4):639-44.
    PMID: 26960504 DOI: 10.4103/0019-509X.178386
    The purpose of this study is to determine the influence of bladder and bowel preparation protocols on the dose-volume histograms (DVHs) of these organs using the cone beam computed tomography (CBCT)-based intensity modulated radiotherapy (IMRT) treatment planning for prostate cancer patients. The pelvic DVHs of 12 prostate cancer patients were studied using CBCT images obtained immediately before each treatment. Six patients had bladder and bowel preparation protocol whilst the other six patients were the control group. Contoured bladder and rectal volumes on CBCT images were compared with planning computed tomography. All patients were treated with IMRT with 7800 cGy in 39 fractions over 8 weeks. Compared with the patient with bladder preparation protocol, patients without bladder preparation instruction had higher bladder volume and dose variation. The maximum variation in bladder volume was as high as 98% in the control group. Without bowel preparation protocol, the rectal volumes were more variability. Owing to changes in rectal filling on the day of treatment, the maximum variation in rectal volume was as high as + 96%. With bowel preparation protocol, the maximum rectum volume variations were less than 25%. The changes in prostate target dose compared with planning dose were minimal as would be expected from positioning with daily image guidance and gold seed implanted.
  2. Shin Low S, Nong Lim C, Yew M, Siong Chai W, Low LE, Manickam S, et al.
    Ultrason Sonochem, 2021 Dec;80:105805.
    PMID: 34706321 DOI: 10.1016/j.ultsonch.2021.105805
    Recent advances in ultrasound (US) have shown its great potential in biomedical applications as diagnostic and therapeutic tools. The coupling of US-assisted drug delivery systems with nanobiomaterials possessing tailor-made functions has been shown to remove the limitations of conventional drug delivery systems. The low-frequency US has significantly enhanced the targeted drug delivery effect and efficacy, reducing limitations posed by conventional treatments such as a limited therapeutic window. The acoustic cavitation effect induced by the US-mediated microbubbles (MBs) has been reported to replace drugs in certain acute diseases such as ischemic stroke. This review briefly discusses the US principles, with particular attention to the recent advancements in drug delivery applications. Furthermore, US-assisted drug delivery coupled with nanobiomaterials to treat different diseases (cancer, neurodegenerative disease, diabetes, thrombosis, and COVID-19) are discussed in detail. Finally, this review covers the future perspectives and challenges on the applications of US-mediated nanobiomaterials.
  3. Saw KY, Hussin P, Loke SC, Azam M, Chen HC, Tay YG, et al.
    Arthroscopy, 2009 Dec;25(12):1391-400.
    PMID: 19962065 DOI: 10.1016/j.arthro.2009.07.011
    PURPOSE: The purpose of the study was to determine whether postoperative intra-articular injections of autologous marrow aspirate (MA) and hyaluronic acid (HA) after subchondral drilling resulted in better cartilage repair as assessed histologically by Gill scoring.
    METHODS: In a goat model we created a 4-mm full-thickness articular cartilage defect in the stifle joint (equivalent to 1.6 cm in the human knee) and conducted subchondral drilling. The animals were divided into 3 groups: group A (control), no injections; group B (HA), weekly injection of 1 mL of sodium hyaluronate for 3 weeks; and group C (HA + MA), similar to group B but with 2 mL of autologous MA in addition to HA. MA was obtained by bone marrow aspiration, centrifuged, and divided into aliquots for cryopreservation. Fifteen animals were equally divided between the groups and sacrificed 24 weeks after surgery, when the joint was harvested, examined macroscopically and histologically.
    RESULTS: Of the 15 animals, 2 from group A had died of non-surgery-related complications and 1 from group C was excluded because of a joint infection. In group A the repair constituted mainly scar tissue, whereas in group B there was less scar tissue, with small amounts of proteoglycan and type II collagen at the osteochondral junction. In contrast, repair cartilage from group C animals showed almost complete coverage of the defect with evidence of hyaline cartilage regeneration. Histology assessed by Gill scoring was significantly better in group C with 1-way analysis of variance yielding an F statistic of 10.611 with a P value of .004, which was highly significant.
    CONCLUSIONS: Postoperative intra-articular injections of autologous MA in combination with HA after subchondral drilling resulted in better cartilage repair as assessed histologically by Gill scoring in a goat model.
    CLINICAL RELEVANCE: After arthroscopic subchondral drilling, this novel technique may result in better articular cartilage regeneration.
  4. Tan CY, Thanawongnuwech R, Arshad SS, Hassan L, Lee CY, Low SE, et al.
    Trop Biomed, 2023 Sep 01;40(3):301-306.
    PMID: 37897162 DOI: 10.47665/tb.40.3.005
    Porcine circovirus type 4 (PCV4) is the newest member in the porcine circovirus family, first reported in 2020. To date, the presence of PCV4 has only been reported in China, South Korea and most recently in Thailand. Detection of PCV4 have been reported in various production stages of pigs from piglets, finishers to sows; associated with a myriad of clinical manifestations including porcine dermatitis and nephropathy syndrome (PDNS), postweaning multisystemic wasting syndrome (PMWS), respiratory, enteric and neurological diseases. While successful virus isolation and culture has yet to be reported, pathogenicity of PCV4 has been demonstrated through infectious clone studies. The objective of this study is to investigate the presence of PCV4 in Malaysian porcine population to update the epidemiology of porcine circoviruses in Malaysia. A total of 49 samples from commercial intensive pig farms, abattoir and wild boar population were subjected to conventional polymerase chain reaction assay to detect PCV4 capsid (cap) genome. Resulting cap nucleotide sequences were analyzed for maximum likelihood phylogeny relationship. Results revealed that PCV4 is present in Peninsular Malaysia at a molecular prevalence of 4.08% (2 / 49 samples). Both PCV4 positive samples originated from clinically healthy finishers. Malaysian PCV4 strains were classified as genotype PCV4b, and were found to be phylogenetically distinct from the China, South Korea and Thailand strains. With this latest update of the novel PCV4 in Malaysia, it is clear that more attention needs to be given to the investigation of novel porcine circoviruses (PCV) and management of PCV diseases.
  5. Tan YK, Khoo KL, Low JA, Wong ZW, Theng CT, Ong TH, et al.
    Ann Acad Med Singap, 1999 Mar;28(2):214-6.
    PMID: 10497669
    We studied the relationship between different ethnic groups, obstructive sleep apnoea (OSA) and ischaemic heart disease. Four hundred and thirty-two inpatients from the medical wards were interviewed. Limited overnight sleep studies were done in 129 of those who had habitual snoring, daytime sleepiness based on an Epworth sleepiness scale of 8 or more, or a large neck size of 40 cm or more. There were 315 Chinese (72.9%), 67 Malays (15.5%), 43 Indians (10%) and 3 from other races (1.4%). The prevalence of OSA was 19.7%, 30% and 12% among the Chinese, Malays and Indians, respectively. The prevalence ratio for OSA was 1.52 in Malays using Chinese patients as the baseline (P = 0.07). The median neck circumference was 37 cm in both racial groups. The median body mass index was 22.7 kg/m2 in Chinese compared to 23.6 kg/m2 in Malays. The median apnoea-hypopnoea index was 22.7, 19.0 and 26.9 events/hour among the Chinese, Malays and Indians, respectively. OSA was independently associated with the prevalence of IHD (adjusted prevalence ratio 1.68; 95% CI: 1.15, 2.46; P = 0.009). The prevalence of ischaemic heart disease (IHD) was 31%, 24% and 28% in Chinese, Malays and Indians, respectively. The prevalence ratio for IHD in Malays compared to Chinese was 0.77. After adjusting for OSA, there was an even greater reduction in the risk of IHD (adjusted prevalence ratio 0.70). This suggests that OSA is a confounder in the relationship between race and ischaemic heart disease.
  6. Radhika S, Lee YL, Low SF, Fazalina MF, Sharifah Majedah IA, Suraya A, et al.
    Med J Malaysia, 2015 Jun;70(3):158-61.
    PMID: 26248778 MyJurnal
    AIM: This study was conducted to measure the cross sectional area (CSA) of the ulnar nerve (UN) in the cubital tunnel and to evaluate the role of high-resolution ultrasonography in the diagnosis of ulnar nerve neuropathy (UNN).

    MATERIALS AND METHODS: This was a cross sectional study with 64 arms from 32 patients (34 neuropathic, 30 nonneuropathic). Diagnosis was confirmed by nerve conduction study and electromyography. The ulnar nerves were evaluated with 15MHz small footprint linear array transducer. The ulnar nerve CSA was measured at three levels with arm extended: at medial epicondyle (ME), 5cm proximal and 5cm distal to ME. Results from the neuropathic and nonneuropathic arms were compared. Independent T-tests and Pearson correlation tests were used. P value of less than 0.05 was considered significant.

    RESULTS: Mean CSA values for the UN at levels 5cm proximal to ME, ME and 5cm distal to ME were 0.055, 0.109, 0.045 cm(2) respectively in the neuropathic group and 0.049, 0.075, 0.042 cm2 respectively in the non-neuropathic group. The CSA of the UN at the ME level was significantly larger in the neuropathic group, with p value of 0.005. However, there was no statistical difference between the groups at 5cm proximal and distal to the ME, with p values of 0.10 and 0.35 respectively.

    CONCLUSION: There is significant difference in CSA values of the UN at ME between the neuropathic and non-neuropathic groups with mean CSA value above the predetermined 0.10cm(2) cut-off point. High-resolution ultrasonography is therefore useful to diagnose and follow up cases of elbow UNN.

  7. Low SC, Ahmad AL, Ideris N, Ng QH
    Bioresour Technol, 2012 Jun;113:219-24.
    PMID: 22153291 DOI: 10.1016/j.biortech.2011.11.048
    The aim of this study was to explore the utilization of polymeric membrane for bio-sensing application in most efficient and rapid way. Customization of membrane formulation via phase separation study to modify its morphologies and properties enable the detection of different pathogens in a specific manner. Experimental findings (FESEM, through-pore distribution, porosity, capillary flow test and protein binding test) verified the predictions of faster capillary flow time and higher membrane's protein binding by the addition of cellulose acetate and nitrocellulose to the membrane casting dope, respectively. Throughout the phase separation study, the potential phase behavior was investigated, which was correlating various membrane structures to its performances for potential pathogens detection in water.
  8. Noh LM, Ismail Z, Zainudin BM, Low SM, Azizi BH, Noah RM, et al.
    Acta Paediatr Jpn, 1995 Jun;37(3):331-5.
    PMID: 7645382
    X linked agammaglobulinemia (XLA) is rarely reported from developing countries especially from South East Asia. It appears that X linked agammaglobulinemia is less common in certain ethnic groups. It is very uncommon in black people in USA and South Africa. In multiracial Malaysia we have documented five XLA in Malays and Indians but not in the Chinese that constitute about 31% of the population. First degree relatives afflicted with XLA or other primary immunodeficiencies occurred more often in our study. All showed lung involvement although the etiologic organisms involved were atypical, being Gram negative.
  9. Ngiu CS, Said MS, Periyasamy P, Low SF
    BMJ Case Rep, 2010;2010.
    PMID: 22778377 DOI: 10.1136/bcr.11.2009.2421
    Rituximab is a B-cell-depleting monoclonal anti-CD20 antibody. It is widely used in haematology and rheumatology. However, usage of rituximab in immunosupressed patient has been associated with various opportunistic infections. The authors reported a case of refractory rheumatoid arthritis treated with rituximab, which later presented with non-resolving pneumonia with pulmonary nodule. Percutaneous computer tomogram guided lung biopsy was arranged to confirm the suspicion of tuberculosis, but did not yield conclusive results. Later, she presented left-chest abscess and underwent incision and drainage. The pus culture and sensitivity confirmed pulmonary nocardiosis with chest wall dissemination. She was treated with 2-week course of trimethoprim sulfamethoxazole and responded. The authors also reviewed published cases of nocardiosis post-rituximab.
  10. Saw KY, Jee C, Ramlan A, Dawam A, Saw YC, Low SF
    Malays Orthop J, 2022 Nov;16(3):128-131.
    PMID: 36589370 DOI: 10.5704/MOJ.2211.019
    Osteochondral lesions of the talus (OLTs) may progress to ankle arthritis needing ankle arthroplasty or arthrodesis. We report five cases of OLTs treated along the principles developed for chondrogenesis of the knee joint with autologous peripheral blood stem cells (PBSCs), resulting in repair and regeneration of the bone and cartilage components. Improvement in Ankle Osteoarthritis Scale (AOS) scores with minimum two years follow-up showed statistical significance (p < 0.05).
  11. George E, Lai MI, Teh LK, Ramasamy R, Goh EH, Asokan K, et al.
    Med J Malaysia, 2011 Dec;66(5):429-34.
    PMID: 22390095 MyJurnal
    Detection and quantification of Hb subtypes of human blood is integral to presumptive identification of thalassaemias. It has been used in neonatal screening of thalassaemia and Hb variants. The use of discarded red blood cells following processing of the cord blood for stem cells provides readily available diagnostic material for thalassaemia screening. In this study, we determined the range of Hb subtypes in 195 consecutive cord blood samples collected for cord blood banking. The 'cord blood samples' analysed were those of the remaining red blood cells after the cord blood was processed for stem cell storage. Quantification of Hb subtypes by high performance liquid chromatography (HPLC) was done on BioRad Variant II Hb testing system. Only 73 (36.5%) of the samples could be analyzed neat without dilution. With a 1:300 dilution with wash solution the acceptable area as recommended by the manufacturer for reading of a C-gram within the 1 to 3 million ranges were achieved in all. Eighteen (9%) 12 showed classical Hb Barts (y4) prerun peaks were confirmed by Sebia Hydrasys automated Hb gel electrophoresis and quantified by Sebia Capillarys 2 capillary electrophoresis. Only 1 (0.5%) was presumptively identified with HbH disease. Due to the limited number of samples no beta-thalassaemia major, Hb E beta-thalassaemia and Hb Barts hydrops fetalis were found. The HPLC assay was possible at a cost US$ 5 per sample and a turnover time of 10 samples per hour without technical difficulties. This study reports an effective and valuable protocol for thalassaemia screening in red blood cells which would otherwise be discarded during cord blood processing. Cord blood with severe and intermediate forms of thalassaemia can be preselected and not stored.
  12. Zhang X, Liu JJ, Sum CF, Ying YL, Tavintharan S, Ng XW, et al.
    Atherosclerosis, 2015 Sep;242(1):22-8.
    PMID: 26162317 DOI: 10.1016/j.atherosclerosis.2015.06.019
    OBJECTIVE: We previously reported ethnic disparity in adverse outcomes among Asians with type 2 diabetes (T2DM) in Singapore. Central arterial stiffness can aggravate systemic vasculopathy by propagating elevated systolic and pulse pressures forward, thereby accentuating global vascular injury. We aim to study ethnic disparity in central arterial stiffness and its determinants in a multi-ethnic T2DM Asian cohort.
    METHODS: Arterial stiffness was estimated by carotid-femoral pulse wave velocity (PWV) and augmentation index (AI) using applanation tonometry method in Chinese (N = 1045), Malays (N = 458) and Indians (N = 468). Linear regression model was used to evaluate predictors of PWV and AI.
    RESULTS: PWV was higher in Malays (10.1 ± 3.0 m/s) than Chinese (9.7 ± 2.8 m/s) and Indians (9.6 ± 3.1 m/s) (P = 0.018). AI was higher in Indians (28.1 ± 10.8%) than Malays (25.9 ± 10.1%) and Chinese (26.1 ± 10.7%) (P < 0.001). Malays remain associated with higher PWV (β = 0.299, P = 0.048) post-adjustment for age, gender, duration of diabetes, hemoglobin A1c, body mass index (BMI), systolic blood pressure (SBP), diastolic blood pressure (DBP), soluble receptor for advanced glycation end-products, urinary albumin-to-creatinine ratio, and insulin usage, which were all independent predictors of PWV. Indians remain associated with higher AI (β = 2.776, P < 0.001) post-adjustment for age, gender, BMI, SBP, DBP, and height, which were independent predictors of AI. These variables explained 27.7% and 33.4% of the variance in PWV and AI respectively.
    CONCLUSIONS: Malays and Indians with T2DM have higher central arterial stiffness, which may explain their higher risk for adverse outcomes. Modifying traditional major vascular risk factors may partially alleviate their excess cardiovascular risk through modulating arterial stiffness.
    KEYWORDS: Arterial stiffness; Augmentation index; Pulse wave velocity; Type 2 diabetes
  13. Ng WM, Katiyar A, Mathivanan V, Teng XJ, Leong S, Low S, et al.
    Langmuir, 2020 May 19;36(19):5085-5095.
    PMID: 32338911 DOI: 10.1021/acs.langmuir.0c00135
    A detailed study of the sedimentation kinetics of iron oxide nanoparticle (IONP) clusters composed of nanospheres and nanorods is presented. Measurements were performed to determine the absorbance of an IONP suspension undergoing sedimentation over time by using a UV-vis spectrophotometer with simultaneous monitoring of the hydrodynamic diameter of the clusters formed with dynamic light scattering (DLS). Mathematical analysis based on Happel's spherical and cylindrical models was conducted to reveal the relationship between the settling velocity of the IONP clusters and their packing density. For the case of IONP clusters composed of rodlike particles, two distinctive phases of sedimentation were recorded, with the occurrence of rapid sedimentation at the beginning of the process (phase I) followed by a slower settling rate (phase II). In sedimentation phase II, even though the nanorod clusters had a hydrodynamic size of >500 nm, which was much larger than that of the nanosphere clusters (∼200 nm), their settling velocity of 0.0038 mm/min was still slower than that of the nanosphere clusters. Such observations were mainly a result of the packing density differences between the formed clusters; due to the end-to-end particle interactions of nanorods, the nanorod clusters were less tightly packed and more permeable. In addition to the mathematical analysis, quartz crystal microbalance with dissipation (QCM-D) was employed to measure the "softness" of the IONP clusters formed, and this physical property can be further related to their packing density. This study illustrated that for a rapidly aggregating system, such as magnetic IONPs, not only do the particle shape and size uniformity contribute to the physical properties of the particle clusters formed but also the nature of the aggregation, either end-to-end and/or side-to-side, should be carefully considered when designing a colloidally stable IONP suspension.
  14. Wong GW, Lim KH, Wan WK, Low SC, Kong SC
    Med J Malaysia, 2015 08;70(4):232-7.
    PMID: 26358020
    BACKGROUND: Eosinophilic gastroenteritis (EG) can mimic symptoms of common gastrointestinal (GI) disorders but responds well to appropriate treatment. Accurate diagnosis is central to effective management. Data on EG in Southeast Asia is lacking. We aim to describe the clinical profiles and treatment outcomes of adult patients with EG in a Singapore Tertiary Hospital.

    MATERIALS AND METHODS: This retrospective study involved archival search of patients with GI biopsies that showed eosinophilic infiltration from January 2004 to December 2012. Patients' clinical data from computerised hospital records and clinical notes was reviewed. Diagnostic criteria for EG included presence of GI symptoms with more than 30 eosinophils/high power field on GI biopsies. Patients with secondary causes for eosinophilia were excluded.

    RESULTS: Eighteen patients with EG were identified (mean age 52 years; male/female: 11/7). Fifteen patients (83%) had peripheral blood eosinophilia. Seven patients (39%) had atopic conditions. Most common symptoms were diarrhoea and abdominal pain. Small intestine was the most common site involved. Endoscopic finding was non-specific. Ten patients were treated with corticosteroids (nine prednisolone, one budesonide): eight patients (89%) responded clinically to prednisolone but four patients (50%) relapsed following tapering-off of prednisolone and required maintenance dose. One patient each responded to diet elimination and montelukast respectively. Half of the remaining six patients who were treated with proton-pump inhibitors, antispasmodic or antidiarrheal agents still remained symptomatic.

    CONCLUSION: Prednisolone is an effective treatment though relapses are common. Small intestine is most commonly involved. EG should be considered in the evaluation of unexplained chronic recurrent GI symptoms.

  15. Low SC, Shaimi R, Thandaithabany Y, Lim JK, Ahmad AL, Ismail A
    Colloids Surf B Biointerfaces, 2013 Oct 1;110:248-53.
    PMID: 23732801 DOI: 10.1016/j.colsurfb.2013.05.001
    Protein adsorption onto membrane surfaces is important in fields related to separation science and biomedical research. This study explored the molecular interactions between protein, bovine serum albumin (BSA), and nitrocellulose films (NC) using electrokinetic phenomena and the effects of these interactions on the streaming potential measurements for different membrane pore morphologies and pH conditions. The data were used to calculate the streaming ratios of membranes-to-proteins and to compare these values to the electrostatic or hydrophobic attachment of the protein molecules onto the NC membranes. The results showed that different pH and membrane pore morphologies contributes to different protein adsorption mechanisms. The protein adsorption was significantly reduced under conditions where the membrane and protein have like-charges due to electrostatic repulsion. At the isoelectric point (IEP) of the protein, the repulsion between the BSA and the NC membrane was at the lowest; thus, the BSA could be easily attached onto the membrane/solution interface. In this case, the protein was considered to be in a compact layer without intermolecular protein repulsions.
  16. Ahmad AL, Low SC, Shukor SR, Ismail A
    J Immunoassay Immunochem, 2012 Jan;33(1):48-58.
    PMID: 22181820 DOI: 10.1080/15321819.2011.591479
    This study was aimed at gaining a quantitative understanding of the effect of protein quantity and membrane pore structure on protein immobilization. The concentration of immobilized protein was measured by staining with Ponceau S and measuring its color intensity. In this study, both membrane morphology and the quantity of deposited protein significantly influenced the quantity of protein immobilization on the membrane surface. The sharpness and intensity of the red protein spots varied depending on the membrane pore structure, indicating a dependence of protein immobilization on this factor. Membranes with smaller pores resulted in a higher color density, corresponding to enhanced protein immobilization and an increased assay sensitivity level. An increased of immobilized volume has a significant jagged outline on the protein spot but, conversely, no difference in binding capacity.
  17. Ahmad AL, Ideris N, Ooi BS, Low SC, Ismail A
    J Immunoassay Immunochem, 2016;37(4):421-37.
    PMID: 27088961 DOI: 10.1080/15321819.2016.1157489
    Statistical experimental design was employed to optimize the preparation conditions of polyvinylidenefluoride (PVDF) membranes. Three variables considered were polymer concentration, dissolving temperature, and casting thickness, whereby the response variable was membrane-protein binding. The optimum preparation for the PVDF membrane was a polymer concentration of 16.55 wt%, a dissolving temperature of 27.5°C, and a casting thickness of 450 µm. The statistical model exhibits a deviation between the predicted and actual responses of less than 5%. Further characterization of the formed PVDF membrane showed that the morphology of the membrane was in line with the membrane-protein binding performance.
  18. Elhusseiny KM, Abd-Elhay FA, Kamel MG, Abd El Hamid Hassan HH, Muhammad El Tanany HH, Hong HT, et al.
    Ann Oncol, 2018 Nov;29 Suppl 9:ix104.
    PMID: 32177708 DOI: 10.1093/annonc/mdy438.035
  19. Low SL, Wong SY, Ooi IH, Hesse M, Städler Y, Schönenberger J, et al.
    Plant Biol (Stuttg), 2016 Jan;18(1):84-97.
    PMID: 25688576 DOI: 10.1111/plb.12320
    Homoplastic evolution of 'unique' morphological characteristics in the Schismatoglottideae - many previously used to define genera - prompted this study to compare morphology and function in connection with pollination biology for Aridarum nicolsonii, Phymatarum borneense and Schottarum sarikeense. Aridarum nicolsonii and P. borneense extrude pollen through a pair of horned thecae while S. sarikeense sheds pollen through a pair of pores on the thecae. Floral traits of spathe constriction, presence and movement of sterile structures on the spadix, the comparable role of horned thecae and thecae pores, the presence of stamen-associated calcium oxalate packages, and the timing of odour emission are discussed in the context of their roles in pollinator management. Pollinators for all investigated species were determined to be species of Colocasiomyia (Diptera: Drosophilidae).
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