Displaying all 12 publications

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  1. Leow SN, Bastion ML
    BMJ Case Rep, 2013;2013.
    PMID: 23645703 DOI: 10.1136/bcr-2013-009664
    To describe a case of familial exudative vitreoretinopathy presenting with unilateral rhegmatogenous retinal detachment in a Malay teenager.
  2. Leow SN, Tang WS
    Malays Fam Physician, 2019;14(3):65-67.
    PMID: 32175043
    Anaphylaxis is a life-threatening emergency, and adrenaline is the mainstay treatment for this condition. However, there have been a few reported cases of patients experiencing cardiovascular complications, such as myocardial infarction and coronary vasospasm, after its use. We highlight such a case in a young, healthy patient and the important differentials to consider.
  3. Zuhaimy H, Leow SN, Vasudevan SK
    BMJ Case Rep, 2017 Aug 09;2017.
    PMID: 28794092 DOI: 10.1136/bcr-2017-221170
    We discuss the diagnostic challenge in an adult patient presented with purely ocular symptoms diagnosed with tuberculous meningitis (TBM). A 38-year-old woman presented with bilateral painless blurring of vision. There were bilateral sixth cranial nerve palsy and bilateral optic disc swelling. Optic nerve function tests were normal. Patient was lucid with no signs of meningism. Brain imaging were normal. She had a positive Mantoux test, high erythrocyte sedimentation rate but no clinical evidence of active pulmonary tuberculosis infection. Her Quantiferon-TB Gold in-tube test was negative. Cerebrospinal fluid analysis revealed a high opening pressure but no biochemical parameters to suggest TBM, hence she was treated as idiopathic intracranial hypertension. A diagnosis of TBM was finally made following a positive PCR for Mycobacterium tuberculosis Her vision improved with reduction in optic disc swelling following antituberculous treatment.
  4. Leow SN, Tang WS, Pararajasingam RP, Ee WS
    Malays Fam Physician, 2020;15(3):35-42.
    PMID: 33329861
    Introduction: Pre-pregnancy care (PPC) is an important part of diabetic care among females in the reproductive age group, as it improves feto-maternal outcomes.

    Objective: We aimed to assess female diabetic patients' perception of PPC and family planning prior to PPC care.

    Methods: This was an observational, cross-sectional survey performed from June 2019 to September 2019, using universal sampling of registered female diabetic patients who fit the inclusion criteria prior to integrated PPC care. A self-administered questionnaire was used to assess patients' perception of PPC.

    Results: A total of 67 patients were recruited for the study. Only 39.4% (n=26) of the patients had heard of PPC. In our study, Code 1 contraception included those methods with a Pearl index of ≤9. Code 2 & 3 contraception included those methods with a Pearl index of >9. Only one-third of patients, 29.9% (n=20), were using Code 1 contraception, although the majority, 79.1% (n=53), felt that they had completed their family. 45 patients (68.2%) felt that they were at risk of developing complications if they were to become pregnant, and 46 patients (69.7%) felt that their health condition was not suitable for another pregnancy. However, only 31.1% (n=14) and 34.8% (n=16) of these patients were using Code 1 contraception, respectively. There were 30 patients (65.2%) who perceived that their health was not suitable for another pregnancy but were only using Code 2 or 3 contraception.

    Conclusion: The patients' perception of PPC was poor. Patients had an inadequate knowledge of the effectiveness of their current contraceptive practice in relation to their intentions for further pregnancy and their self-perceived risk in case of future conception. We suggest that integration of PPC into routine follow-ups for other high-risk medical diseases, such as hypertension, heart disease, and epilepsy, be considered in future practice.
  5. New SH, Leow SN, Vasudevan SK, Idris IB, Tang SF, Din NM
    PLoS One, 2021;16(2):e0246830.
    PMID: 33630879 DOI: 10.1371/journal.pone.0246830
    OBJECTIVE: To evaluate the retinal nerve fiber layer (RNFL) and macular thicknesses and identify systemic risk factors for thinning of these layers in patients with metabolic syndrome (MetS).

    METHODOLOGY: A cross-sectional observational study was performed on patients diagnosed with MetS and compared to normal controls. All patients underwent ophthalmic and anthropometric examination, serological and biochemical blood investigations; and ocular imaging using spectral-domain optical coherence tomography. Patients with ocular pathology were excluded. Unpaired t-test was used to compare mean thickness between the two groups. One-way ANOVA with Bonferroni correction for multiple comparisons was used to compare mean thickness between different tertiles of MetS parameters, and a generalized estimating equation was used to correct for inter-eye correlation and to assess association between mean thickness and covariates.

    RESULTS: Two hundred and forty-eight eyes from 124 participants (1:1 ratio of MetS patients to controls) were included. Age ranged between 30 to 50 years old, and mean age was 40 ± 6.6 years. RNFL thickness was lower globally (93.6 ± 9.9 μm vs 99.0 ± 9.3, p<0.001) and in the inferior (124.5 ± 17.5 μm vs 131.0 ± 16.4 μm, p = 0.002), superior (117.2 ± 16.0 μm vs 126.3 ± 14.4 μm, p<0.001) and temporal (65.5 ± 10.2 μm vs 69.5 ± 9.8, p = 0.002) sectors in MetS patients compared to controls. Only the central (237.0 ± 14.0 μm vs 243.6 ± 18.0 μm, p = 0.002) and inferior parafoveal (307.8 ± 20.9 vs 314.6 ± 14.6, p = 0.004) area of the macula was significantly thinner. The inferior RNFL sector had the most difference (mean difference = 9.1 μm). The Generalized Estimating Equation found that, after adjusting for age, diastolic blood pressure, BMI, HDL and obesity; the number of MetS components and elevated triglyceride levels were independent risk factors for reduced thickness in global RNFL (β = -4.4, 95% CI = -7.29 to -1.5, p = 0.003) and inferior parafovea (β = -6.85, 95% CI = -11.58 to -2.13, p = 0.004) thickness respectively.

    CONCLUSION: RNFL thinning was seen more than macula thinning in MetS patients, suggesting RNFL susceptibility to neurodegeneration than the macula. A higher number of metabolic components and elevated triglyceride levels were independent risk factors for retinal thinning in this group of patients.

  6. Leow SN, Tay CL, Ng WW, Mior Mohammad Jafri MN
    Malays Fam Physician, 2022 Nov 30;17(3):89-96.
    PMID: 36606163 DOI: 10.51866/oa.107
    INTRODUCTION: Obesity is associated with an increased risk for non-communicable diseases. Local studies have shown that 33.1% of healthcare providers (HCPs) are overweight, while 21.1% are obese. Interventions that consist of diet, physical exercise and cognitive behavioural training have been shown to be successful in reducing weight.

    METHOD: We designed a weight loss programme for our HCPs named the 'Fit and Trimmed Staff programme, which consisted of 3 months of group education on obesity-related health problems led by a doctor, a pharmacist, a nutritionist and an occupational therapist among HCPs. Monthly individual dietary counselling by a nutritionist was also provided for 6 months. We measured the body weight, body mass index, percentage of body fat, visceral fat and percentage of skeletal muscle of the HCPs before and after the intervention.

    RESULTS: Forty-five (56.25%) HCPs at Simpang Health Clinic were either overweight or obese; the majority of them were drivers and administrative clerks (100%), followed by health attendants (69.2%) and medical assistants (63.6%). At 6 months post-intervention, there was a trend towards a non-significant reduction in the fat percentage (median=-0.8%, P=0.423). Approximately 42% (n=19) of the HCPs lost weight, while 58% gained weight. Weight loss was observed more commonly in the male HCPs (>50%) than in the female HCPs.

    CONCLUSION: A weight loss programme solely consisting of health discussion and nutritional advice is inadequate to induce weight reductions. A multimodal approach may be considered in managing weight among HCPs.

  7. Shirley Ding SL, Leow SN, Munisvaradass R, Koh EH, Bastion ML, Then KY, et al.
    Eye (Lond), 2016 Oct;30(10):1293-1309.
    PMID: 27285322 DOI: 10.1038/eye.2016.94
    Erythropoietin (EPO) is a glycoprotein hormone conventionally thought to be responsible only in producing red blood cells in our body. However, with the discovery of the presence of EPO and EPO receptors in the retinal layers, the EPO seems to have physiological roles in the eye. In this review, we revisit the role of EPO in the eye. We look into the biological role of EPO in the development of the eye and the physiologic roles that it has. Apart from that, we seek to understand the mechanisms and pathways of EPO that contributes to the therapeutic and pathological conditions of the various ocular disorders such as diabetic retinopathy, retinopathy of prematurity, glaucoma, age-related macular degeneration, optic neuritis, and retinal detachment. With these understandings, we discuss the clinical applications of EPO for treatment of ocular disorders, modes of administration, EPO formulations, current clinical trials, and its future directions.
  8. Leow SN, Luu CD, Hairul Nizam MH, Mok PL, Ruhaslizan R, Wong HS, et al.
    PLoS One, 2015;10(6):e0128973.
    PMID: 26107378 DOI: 10.1371/journal.pone.0128973
    To investigate the safety and efficacy of subretinal injection of human Wharton's Jelly-derived mesenchymal stem cells (hWJ-MSCs) on retinal structure and function in Royal College of Surgeons (RCS) rats.
  9. Looi SY, Bastion MC, Leow SN, Luu CD, Hairul NMH, Ruhaslizan R, et al.
    Indian J Ophthalmol, 2022 Jan;70(1):201-209.
    PMID: 34937239 DOI: 10.4103/ijo.IJO_473_21
    Purpose: There are no effective treatments currently available for optic nerve transection injuries. Stem cell therapy represents a feasible future treatment option. This study investigated the therapeutic potential of human umbilical cord-derived mesenchymal stem cell (hUC-MSC) transplantation in rats with optic nerve injury.

    Methods: Sprague-Dawley (SD) rats were divided into three groups: a no-treatment control group (n = 6), balanced salt solution (BSS) treatment group (n = 6), and hUC-MSCs treatment group (n = 6). Visual functions were assessed by flash visual evoked potential (fVEP) at baseline, Week 3, and Week 6 after optic nerve crush injury. Right eyes were enucleated after 6 weeks for histology.

    Results: The fVEP showed shortened latency delay and increased amplitude in the hUC-MSCs treated group compared with control and BSS groups. Higher cellular density was detected in the hUC-MSC treated group compared with the BSS and control groups. Co-localized expression of STEM 121 and anti-S100B antibody was observed in areas of higher nuclear density, both in the central and peripheral regions.

    Conclusion: Peribulbar transplantation of hUC-MSCs demonstrated cellular integration that can potentially preserve the optic nerve function with a significant shorter latency delay in fVEP and higher nuclear density on histology, and immunohistochemical studies observed cell migration particularly to the peripheral regions of the optic nerve.

  10. Mok PL, Leow SN, Koh AE, Mohd Nizam HH, Ding SL, Luu C, et al.
    Int J Mol Sci, 2017 Feb 08;18(2).
    PMID: 28208719 DOI: 10.3390/ijms18020345
    Mesenchymal stem cells are widely used in many pre-clinical and clinical settings. Despite advances in molecular technology; the migration and homing activities of these cells in in vivo systems are not well understood. Labelling mesenchymal stem cells with gold nanoparticles has no cytotoxic effect and may offer suitable indications for stem cell tracking. Here, we report a simple protocol to label mesenchymal stem cells using 80 nm gold nanoparticles. Once the cells and particles were incubated together for 24 h, the labelled products were injected into the rat subretinal layer. Micro-computed tomography was then conducted on the 15th and 30th day post-injection to track the movement of these cells, as visualized by an area of hyperdensity from the coronal section images of the rat head. In addition, we confirmed the cellular uptake of the gold nanoparticles by the mesenchymal stem cells using transmission electron microscopy. As opposed to other methods, the current protocol provides a simple, less labour-intensive and more efficient labelling mechanism for real-time cell tracking. Finally, we discuss the potential manipulations of gold nanoparticles in stem cells for cell replacement and cancer therapy in ocular disorders or diseases.
  11. Koh AE, Alsaeedi HA, Rashid MBA, Lam C, Harun MHN, Saleh MFBM, et al.
    J. Photochem. Photobiol. B, Biol., 2019 Jul;196:111514.
    PMID: 31154277 DOI: 10.1016/j.jphotobiol.2019.111514
    Retinal disorders account for a large proportion of ocular disorders that can lead to visual impairment or blindness, and yet our limited knowledge in the pathogenesis and choice of appropriate animal models for new treatment modalities may contribute to ineffective therapies. Although genetic in vivo models are favored, the variable expressivity and penetrance of these heterogeneous disorders can cause difficulties in assessing potential treatments against retinal degeneration. Hence, an attractive alternative is to develop a chemically-induced model that is both cost-friendly and standardizable. Sodium iodate is an oxidative chemical that is used to simulate late stage retinitis pigmentosa and age-related macular degeneration. In this study, retinal degeneration was induced through systemic administration of sodium iodate (NaIO3) at varying doses up to 80 mg/kg in Sprague-Dawley rats. An analysis on the visual response of the rats by electroretinography (ERG) showed a decrease in photoreceptor function with NaIO3 administration at a dose of 40 mg/kg or greater. The results correlated with the TUNEL assay, which revealed signs of DNA damage throughout the retina. Histomorphological analysis also revealed extensive structural lesions throughout the outer retina and parts of the inner retina. Our results provided a detailed view of NaIO3-induced retinal degeneration, and showed that the administration of 40 mg/kg NaIO3 was sufficient to generate disturbances in retinal function. The pathological findings in this model reveal a degenerating retina, and can be further utilized to develop effective therapies for RPE, photoreceptor, and bipolar cell regeneration.
  12. Alsaeedi HA, Koh AE, Lam C, Rashid MBA, Harun MHN, Saleh MFBM, et al.
    J. Photochem. Photobiol. B, Biol., 2019 Sep;198:111561.
    PMID: 31352000 DOI: 10.1016/j.jphotobiol.2019.111561
    Blindness and vision loss contribute to irreversible retinal degeneration, and cellular therapy for retinal cell replacement has the potential to treat individuals who have lost light sensitive photoreceptors in the retina. Retinal cells are well characterized in function, and are a subject of interest in cellular replacement therapy of photoreceptors and the retinal pigment epithelium. However, retinal cell transplantation is limited by various factors, including the choice of potential stem cell source that can show variability in plasticity as well as host tissue integration. Dental pulp is one such source that contains an abundance of stem cells. In this study we used dental pulp-derived mesenchymal stem cells (DPSCs) to mitigate sodium iodate (NaIO3) insult in a rat model of retinal degeneration. Sprague-Dawley rats were first given an intravitreal injection of 3 × 105 DPSCs as well as a single systemic administration of NaIO3 (40 mg/kg). Electroretinography (ERG) was performed for the next two months and was followed-up by histological analysis. The ERG recordings showed protection of DPSC-treated retinas within 4 weeks, which was statistically significant (* P ≤ .05) compared to the control. Retinal thickness of the control was also found to be thinner (*** P ≤ .001). The DPSCs were found integrated in the photoreceptor layer through immunohistochemical staining. Our findings showed that DPSCs have the potential to moderate retinal degeneration. In conclusion, DPSCs are a potential source of stem cells in the field of eye stem cell therapy due to its protective effects against retinal degeneration.
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