Displaying publications 1 - 20 of 21 in total

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  1. Kamalden TA, Lingam G, Sundar G
    Ocul Oncol Pathol, 2014 Oct;1(1):13-8.
    PMID: 27175357 DOI: 10.1159/000363454
    Choroidal osteoma is a benign ossifying tumor of the choroid, consisting of mature bone tissue. It has been described to enlarge and evolve at varying rates over time. Here, we report and quantify the progression of a unilateral choroidal osteoma in a 7-year-old boy by fundus photography, and document tumor remodeling by spectral domain optical coherence tomography images.
  2. Kamalden TA, Choo MM, Kadir K, Khaliddin N
    Neuroradiol J, 2009 Jan 20;21(6):861-4.
    PMID: 24257059
    Orbital arteriovenous malformation is a rare condition which poses a management problem in view of the complexity of the vessels involved, and the potentially blinding and life-threatening complications from the modes of treatment. Treatment requires obliteration of the abnormal vascular communication. Vision may be adversely affected by the condition itself, as well as a result of invasive treatment modalities. This case reports such a situation where the visual outcome was severely affected following embolization of the feeding vessels.
  3. Hoskin AK, Watson S, Kamalden TA
    Inj Prev, 2023 Apr;29(2):116-120.
    PMID: 36564168 DOI: 10.1136/ip-2022-044564
    OBJECTIVES: To report the nature of badminton-related eye injuries in the published literature.

    METHODS: A review of the literature with key word and MeSH terms: 'Eye injury', 'Ocular trauma', 'Badminton' 'Shuttlecock' using CENTRAL, MEDLINE, EMBASE and Informit Health Collection databases. Papers were reviewed to assess the circumstances of the injury, patient demographics and clinical data.

    RESULTS: 19 studies from 1974 to 2020 from 12 countries reported 378 monocular badminton-related eye injuries from 378 patients with a male-to-female ratio of 2.5:1. A closed globe injury was sustained in 97% of eyes and a shuttlecock responsible for 85% of injuries. Doubles play, the shuttlecock and a lack of eye protection were associated with eye injury.

    CONCLUSION: Vision impairment was associated with the majority of badminton-related eye injuries, and doubles play, the shuttlecock and a lack of eye protection were risk factors.

  4. Addenan M, May CM, Hooi TK, Ismail F, Kamalden TA
    Oman J Ophthalmol, 2018 12 7;11(3):284-287.
    PMID: 30505126 DOI: 10.4103/ojo.OJO_149_2017
    Langerhans cell histiocytosis (LCH) is rarely encountered in ophthalmology practice. It is a spectrum of disorder characterized by accumulation of histiocytes in various tissues. Diagnosis is challenging as it may simulate periorbital hematoma, rhabdomyosarcoma, and neuroblastoma. We report a case of unifocal LCH with orbital extension. Diagnosis was obtained from incisional biopsy, and histopathological examination showed numerous histiocytes with eosinophilic infiltrations. The presence of Langerhans cells was confirmed by the presence of protein S-100, CD1a, and/or Langerin (CD207). Treatment depends on the degree of organ involvement. She responded well to cytotoxic drugs and steroids. This emphasized that prompt tissue diagnosis is crucial for early management.
  5. Chong KL, Samsudin A, Keng TC, Kamalden TA, Ramli N
    J Glaucoma, 2017 Feb;26(2):e37-e40.
    PMID: 27599172 DOI: 10.1097/IJG.0000000000000542
    PURPOSE: To evaluate the effect of nocturnal intermittent peritoneal dialysis (NIPD) on intraocular pressure (IOP) and anterior segment optical coherence tomography (ASOCT) parameters. Systemic changes associated with NIPD were also analyzed.

    METHODS: Observational study. Nonglaucomatous patients on NIPD underwent systemic and ocular assessment including mean arterial pressure (MAP), body weight, serum osmolarity, visual acuity, IOP measurement, and ASOCT within 2 hours both before and after NIPD. The Zhongshan Angle Assessment Program (ZAAP) was used to measure ASOCT parameters including anterior chamber depth, anterior chamber width, anterior chamber area, anterior chamber volume, lens vault, angle opening distance, trabecular-iris space area, and angle recess area. T tests and Pearson correlation tests were performed with P<0.05 considered statistically significant.

    RESULTS: A total of 46 eyes from 46 patients were included in the analysis. There were statistically significant reductions in IOP (-1.8±0.6 mm Hg, P=0.003), MAP (-11.9±3.1 mm Hg, P<0.001), body weight (-0.7±2.8 kg, P<0.001), and serum osmolarity (-3.4±2.0 mOsm/L, P=0.002) after NIPD. All the ASOCT parameters did not have any statistically significant changes after NIPD. There were no statistically significant correlations between the changes in IOP, MAP, body weight, and serum osmolarity (all P>0.05).

    CONCLUSIONS: NIPD results in reductions in IOP, MAP, body weight, and serum osmolarity in nonglaucomatous patients.

  6. Teh D, Mohamad NF, Lim E, Zulkiflee AB, Narayanan P, Kamalden TA
    Comput Assist Surg (Abingdon), 2016 Dec;21(1):25-28.
    PMID: 27973957
    Foreign bodies lodged in the intraconal space of the orbit pose a surgical challenge due to its deep location behind the globe. Image-guided endoscopic transnasal surgery facilitates the localization of the metallic foreign bodies and enables its safe removal with minimal surrounding tissue damage and optic nerve injury.
  7. Beshay N, Keay L, Dunn H, Kamalden TA, Hoskin AK, Watson SL
    Injury, 2017 Jul;48(7):1348-1354.
    PMID: 28438416 DOI: 10.1016/j.injury.2017.04.035
    BACKGROUND: Open globe injuries (OGIs) account for 44% of the cost of ocular trauma within Australia. It is estimated that 90% of ocular trauma is preventable. However, there have been few epidemiological studies within Australia that have identified groups at risk of OGIs specifically. The aim of our study was to review the epidemiology of OGIs presenting to a tertiary referral eye hospital in Australia.

    METHODS: The Birmingham Eye Trauma Terminology (BETT) system was used to classify injuries as globe ruptures, penetrating eye injuries (PEIs), intraocular foreign bodies (IOFBs) or perforating injuries. Demographic data, past ocular history, mechanism of trauma, ocular injuries, and best-corrected visual acuity (BCVA) before and after treatment were recorded.

    RESULTS: The 205 OGIs included 80 globe ruptures, 71 PEIs, 48 IOFBs and six perforating injuries. Falls predominated in older age groups compared to the other mechanisms of injury (p<0.0001). A fall was responsible for 33 globe ruptures and 82% of these had a history of previous intraocular surgery. Globe rupture and perforating injuries had poorer visual outcomes (p<0.05), consistent with previous studies. Alcohol was implicated in 20 cases of OGI, with 11 of these due to assault. PEIs and IOFBs commonly occurred while working with metal. BCVA was significantly worse following removal of an intraocular foreign body. We found presenting BCVA to be a good predictor of BCVA at the time of discharge.

    CONCLUSIONS: The causes of OGI varied in association with age, with older people mostly incurring their OGI through falls and younger adults through assault and working with metal. Globe ruptures occurring after a fall often had a history of intraocular surgery. The initial BCVA is useful for non-ophthalmologists who are unfamiliar with the ocular trauma score to help predict the BCVA following treatment.

  8. Kassim M, Mansor M, Kamalden TA, Shariffuddin II, Hasan MS, Ong G, et al.
    Shock, 2014 Aug;42(2):154-60.
    PMID: 24667629 DOI: 10.1097/SHK.0000000000000179
    Excessive free radical production by immune cells has been linked to cell death and tissue injury during sepsis. Peroxynitrite is a short-lived oxidant and a potent inducer of cell death that has been identified in several pathological conditions. Caffeic acid phenethyl ester (CAPE) is an active component of honeybee products and exhibits antioxidant, anti-inflammatory, and immunomodulatory activities. The present study examined the ability of CAPE to scavenge peroxynitrite in RAW 264.7 murine macrophages stimulated with lipopolysaccharide/interferon-γ that was used as an in vitro model. Conversion of 123-dihydrorhodamine to its oxidation product 123-rhodamine was used to measure peroxynitrite production. Two mouse models of sepsis (endotoxemia and cecal ligation and puncture) were used as in vivo models. The level of serum 3-nitrotyrosine was used as an in vivo marker of peroxynitrite. The results demonstrated that CAPE significantly improved the viability of lipopolysaccharide/interferon-γ-treated RAW 264.7 cells and significantly inhibited nitric oxide production, with effects similar to those observed with an inhibitor of inducible nitric oxide synthase (1400W). In addition, CAPE exclusively inhibited the synthesis of peroxynitrite from the artificial substrate SIN-1 and directly prevented the peroxynitrite-mediated conversion of dihydrorhodamine-123 to its fluorescent oxidation product rhodamine-123. In both sepsis models, CAPE inhibited cellular peroxynitrite synthesis, as evidenced by the absence of serum 3-nitrotyrosine, an in vivo marker of peroxynitrite. Thus, CAPE attenuates the inflammatory responses that lead to cell damage and, potentially, cell death through suppression of the production of cytotoxic molecules such as nitric oxide and peroxynitrite. These observations provide evidence of the therapeutic potential of CAPE treatment for a wide range of inflammatory disorders.
  9. Choo MM, Yeong CM, Grigg JR, Khaliddin N, Kadir AJ, Barnes EH, et al.
    Medicine (Baltimore), 2018 Nov;97(48):e13357.
    PMID: 30508927 DOI: 10.1097/MD.0000000000013357
    To report observations of horizontal corneal diameter (HCD) and central corneal thickness (CCT) changes in premature infants with stable optic disc cupping and intraocular pressures (IOPs). The HCD and CCT at term serve as a baseline for premature infants.Sixty-three premature infants were enrolled in a prospective case series. HCD, CCT, and IOP were measured. RetCam images of the optic discs were used to evaluate the cup-disc ratio (CDR) and read by an independent masked observer. Data were collected at between preterm (32-36 weeks) and again at term (37-41 weeks) postconceptual age. Left eye measurements were used for statistical analysis. Left eye findings were combined to construct predictive models for HCD and CCT.The mean HCD was 9.1 mm (standard deviation [SD] = 0.7 mm) at preterm and 10.0 mm (SD = 0.52 mm) at term. The mean CCT preterm was 618.8 (SD = 72.9) μm and at term 563.9 (SD = 50.7) μm, respectively. The average preterm CDR was 0.31 and at maturity was 0.33. Average IOP of preterm and term was 13.1 and 14.11 mm Hg, respectively. There was significant linear correlation between HCD with the postmenstrual age (r = 0.40, P 
  10. Sharif U, Mahmud NM, Kay P, Yang YC, Harding SP, Grierson I, et al.
    J Cell Mol Med, 2019 01;23(1):405-416.
    PMID: 30338926 DOI: 10.1111/jcmm.13944
    The retinal pigment epithelium (RPE) plays a central role in neuroretinal homoeostasis throughout life. Altered proteolysis and inflammatory processes involving RPE contribute to the pathophysiology of age-related macular degeneration (AMD), but the link between these remains elusive. We report for the first time the effect of advanced glycation end products (AGE)-known to accumulate on the ageing RPE's underlying Bruch's membrane in situ-on both key lysosomal cathepsins and NF-κB signalling in RPE. Cathepsin L activity and NF-κB effector levels decreased significantly following 2-week AGE exposure. Chemical cathepsin L inhibition also decreased total p65 protein levels, indicating that AGE-related change of NF-κB effectors in RPE cells may be modulated by cathepsin L. However, upon TNFα stimulation, AGE-exposed cells had significantly higher ratio of phospho-p65(Ser536)/total p65 compared to non-AGEd controls, with an even higher fold increase than in the presence of cathepsin L inhibition alone. Increased proportion of active p65 indicates an AGE-related activation of NF-κB signalling in a higher proportion of cells and/or an enhanced response to TNFα. Thus, NF-κB signalling modulation in the AGEd environment, partially regulated via cathepsin L, is employed by RPE cells as a protective (para-inflammatory) mechanism but renders them more responsive to pro-inflammatory stimuli.
  11. Choo MM, Grigg J, Barnes EH, Khaliddin N, Kamalden TA, Ahmad Kamar A, et al.
    BMJ Open Ophthalmol, 2021;6(1):e000626.
    PMID: 33768163 DOI: 10.1136/bmjophth-2020-000626
    Objective: An ongoing third epidemic of retinopathy of prematurity (ROP) is contributed largely by developing nations. We describe a cohort of infants in a single neonatal unit where two limits of oxygen saturation were administered, to show real-world outcomes from trend in neonatology for higher oxygen to improve survival.

    Methods and analysis: This retrospective, comparative study of prospectively collected data in an ROP screening programme included infants indicated by gestational age ≤32 weeks, birth weight <1501 g, ventilation for 7 days or requiring oxygen >1 month, who underwent dilated fundoscopic examination from age 4 weeks, every 2 weeks until full retinal vascularisation. Infants with ROP were examined weekly and treated where indicated. Data were divided into two epochs. Epoch 1 oxygen saturation targets were [88-92%], epoch 2 targets [90-95% (99%)] with allowance of increase to 20% for several hours after procedures. Outcome measures included development of ROP, treatment, mortality, sepsis and intraventricular haemorrhage.

    Results: A total of 651 infants underwent examination between 2003 and 2016. The incidence of ROP in epoch 1 was 29.1% and epoch 2 was 29.3% (p=0.24). ROP progression doubled in epoch 2 (5 vs 11%, p=0.006), proportion of cases treated halved (14% vs 6%, p=0.0005), sepsis was halved (78.5% vs 41.2%, p<0.0001) and intraventricular haemorrhage doubled (20.2% vs 43.8%, p=0.0001) in epoch 2. Mortality was 4% and 0% in epochs 1 and 2, respectively.

    Conclusion: Incidence of ROP did not differ, although ROP cases that worsened doubled with higher oxygen targets. ROP cases requiring treatment decreased, as did sepsis and mortality. Intraventricular haemorrhage cases doubled.

  12. Paraoan L, Sharif U, Carlsson E, Supharattanasitthi W, Mahmud NM, Kamalden TA, et al.
    Prog Retin Eye Res, 2020 11;79:100859.
    PMID: 32278708 DOI: 10.1016/j.preteyeres.2020.100859
    Secretory proteostasis integrates protein synthesis, processing, folding and trafficking pathways that are essential for efficient cellular secretion. For the retinal pigment epithelium (RPE), secretory proteostasis is of vital importance for the maintenance of the structural and functional integrity of apical (photoreceptors) and basal (Bruch's membrane/choroidal blood supply) sides of the environment it resides in. This integrity is achieved through functions governed by RPE secreted proteins, which include extracellular matrix modelling/remodelling, angiogenesis and immune response modulation. Impaired RPE secretory proteostasis affects not only the extracellular environment, but leads to intracellular protein aggregation and ER-stress with subsequent cell death. Ample recent evidence implicates dysregulated proteostasis as a key factor in the development of age-related macular degeneration (AMD), the leading cause of blindness in the developed world, and research aiming to characterise the roles of various proteins implicated in AMD-associated dysregulated proteostasis unveiled unexpected facets of the mechanisms involved in degenerative pathogenesis. This review analyses cellular processes unveiled by the study of the top 200 transcripts most abundantly expressed by the RPE/choroid in the light of the specialised secretory nature of the RPE. Functional roles of these proteins and the mechanisms of their impaired secretion, due to age and genetic-related causes, are analysed in relation to AMD development. Understanding the importance of RPE secretory proteostasis in relation to maintaining retinal health and how it becomes impaired in disease is of paramount importance for the development and assessment of future therapeutic advancements involving gene and cell therapies.
  13. Wong KH, Nam HY, Lew SY, Naidu M, David P, Kamalden TA, et al.
    Pharmaceuticals (Basel), 2022 Jan 14;15(1).
    PMID: 35056157 DOI: 10.3390/ph15010101
    Age-related macular degeneration (AMD) is a multifactorial disease associated with anatomical changes in the inner retina. Despite tremendous advances in clinical care, there is currently no cure for AMD. This review aims to evaluate the published literature on the therapeutic roles of natural antioxidants in AMD. A literature search of PubMed, Web of Science and Google Scholar for peer-reviewed articles published between 1 January 2011 and 31 October 2021 was undertaken. A total of 82 preclinical and 18 clinical studies were eligible for inclusion in this review. We identified active compounds, carotenoids, extracts and polysaccharides, flavonoids, formulations, vitamins and whole foods with potential therapeutic roles in AMD. We evaluated the integral cellular signaling pathways including the activation of antioxidant pathways and angiogenesis pathways orchestrating their mode of action. In conclusion, we examined the therapeutic roles of natural antioxidants in AMD which warrant further study for application in clinical practice. Our current understanding is that natural antioxidants have the potential to improve or halt the progression of AMD, and tailoring therapeutics to the specific disease stages may be the key to preventing irreversible vision loss.
  14. Kamalden TA, Macgregor-Das AM, Kannan SM, Dunkerly-Eyring B, Khaliddin N, Xu Z, et al.
    Antioxid Redox Signal, 2017 Nov 01;27(13):913-930.
    PMID: 28173719 DOI: 10.1089/ars.2016.6844
    AIMS: MicroRNAs (miRNAs), one type of noncoding RNA, modulate post-transcriptional gene expression in various pathogenic pathways in type 2 diabetes (T2D). Currently, little is known about how miRNAs influence disease pathogenesis by targeting cells at a distance. The purpose of this study was to investigate the role of exosomal miRNAs during T2D.

    RESULTS: We show that miR-15a is increased in the plasma of diabetic patients, correlating with disease severity. miR-15 plays an important role in insulin production in pancreatic β-cells. By culturing rat pancreatic β-cells (INS-1) cells in high-glucose media, we identified a source of increased miR-15a in the blood as exosomes secreted by pancreatic β-cells. We postulate that miR-15a, produced in pancreatic β-cells, can enter the bloodstream and contribute to retinal injury. miR-15a overexpression in Müller cells can be induced by exposing Müller cells to exosomes derived from INS-1 cells under high-glucose conditions and results in oxidative stress by targeting Akt3, which leads to apoptotic cell death. The in vivo relevance of these findings is supported by results from high-fat diet and pancreatic β-cell-specific miR-15a-/- mice.

    INNOVATION: This study highlights an important and underappreciated mechanism of remote cell-cell communication (exosomal transfer of miRNA) and its influence on the development of T2D complications.

    CONCLUSION: Our findings suggest that circulating miR-15a contributes to the pathogenesis of diabetes and supports the concept that miRNAs released by one cell type can travel through the circulation and play a role in disease progression via their transfer to different cell types, inducing oxidative stress and cell injury. Antioxid. Redox Signal. 27, 913-930.

  15. Azanan MS, Chandrasekaran S, Rosli ES, Chua LL, Oh L, Chin TF, et al.
    J Pediatr Hematol Oncol, 2020 08;42(6):e394-e400.
    PMID: 32118813 DOI: 10.1097/MPH.0000000000001766
    BACKGROUND: Microvascular endothelial dysfunction is central to the pathogenesis of cardiovascular disease (CVD). The eye offers direct access for endothelial health assessment via the retinal microvasculature. The aim of the study was to investigate whether image-based retinal vessel analysis is a feasible method of assessing endothelial health in survivors of childhood acute lymphoblastic leukemia (cALL).

    MATERIALS AND METHODS: Cardiovascular risk factors (CRFs) were estimated using the 30-year Framingham Risk Score in 73 childhood leukemia survivors (median age: 25; median years from diagnosis: 19) and 78 healthy controls (median age: 23). Radial arterial stiffness was measured using pulse wave analyzer, while endothelial activation markers were measured by soluble intercellular adhesion molecule 1 (sICAM-1) and soluble vascular cell adhesion molecule 1 (sVCAM-1). Retinal fundus images were analyzed for central retinal artery/vein equivalents (CRAE/CRVE) and arteriolar-venular ratio (AVR).

    RESULTS: cALL survivors had higher CRF (P<0.0001), arterial stiffness (P=0.001), and sVCAM-1 (P=0.007) compared with controls. Survivors also had significantly higher CRVE (P=0.021) while AVR was significantly lower (P=0.026) in survivors compared with controls, compatible with endothelial dysfunction. In cALL survivors with intermediate risk for CVD, CRAE, and AVR are significantly lower, while sVCAM-1 and sICAM-1 are significantly higher when compared with survivors with low CVD risk after adjusting with covariates (age, sex, and smoking status).

    CONCLUSIONS: cALL survivors have an increased risk of CVD compared with age-matched peers. The survivors demonstrated microvasculopathy, as measured by retinal vascular analysis, in addition to physical and biochemical evidence of endothelial dysfunction. These changes predate other measures of CVD. Retinal vessel analysis may be utilized as a robust screening tool for identifying survivors at increased risk for developing CVD.

  16. Chandrasekaran S, Ramli N, Ahmad MJ, Effendi I, Amir NN, Chow RC, et al.
    J Adolesc Young Adult Oncol, 2021 08;10(4):425-431.
    PMID: 32996803 DOI: 10.1089/jayao.2020.0064
    Purpose: Childhood cancer survivors (CCS) demonstrate features of premature aging in a multitude of organ systems. The aim of this pilot study is to determine the presence of premature ocular aging features in CCS, specifically childhood acute lymphoblastic leukemia (ALL) survivors. Methods: This prospective case-control study was conducted over a period of 21 months, starting July 2015 till March 2017. A total of 59 childhood ALL survivors who attended the Paediatric Oncology Clinic of University Malaya Medical Centre (UMMC) and 48 age, race, and gender-matched controls went through a series of ocular examinations and tests. Inclusion criteria used to recruit survivors were age above 16 years, history of ALL in childhood, completion of treatment for ALL, and a remission period of at least 5 years. Patients with ocular disease and those who received hematopoietic stem cell transplantation were excluded. The parameters measured were visual acuity, amplitude of accommodation, pupil cycle time (PCT), and tear break-up time (TBUT). Results: Survivors of childhood ALL demonstrated significant differences in amplitude of accommodation, PCT, and TBUT compared to age-matched controls. Survivors had a lower median (interquartile range [IQR]) amplitude of accommodation compared to controls (11.0 D [9.0-13.0] vs. 12.0 D [10.5-15]; p = 0.045). Survivors also showed a longer median (IQR) PCT in comparison to controls (931.00 mseconds (857.00-1063.00) vs. 875.50 mseconds (825.75-966.00); p = 0.024). In addition, median (IQR) TBUT was worse in survivors in comparison to the control group (9 seconds [6-13] vs. 11 seconds [10-15]; p = 0.001). Conclusion: Survivors of childhood ALL demonstrate premature ocular aging features compared to age-matched controls. Thus, survivors may benefit from having ocular examinations as part of their routine late-effects screening to detect age-related ocular morbidities early in its course.
  17. Hoskin AK, Low R, Sen P, Mishra C, Kamalden TA, Woreta F, et al.
    PMID: 34173879 DOI: 10.1007/s00417-021-05266-1
    PURPOSE: To detail the methodology for a novel ocular trauma registry and utilize the registry to determine the demographics, nature of injury, and associations of severe visual loss for open globe injuries (OGI).

    METHODS: Thirteen hospitals in 7 countries used International Globe and Adnexal Trauma Epidemiology Study (IGATES) platform. Patients presenting between April 2009 and 2020 with OGI (with or without) adnexal involvement or intraocular foreign body (IOFB) were included.

    RESULTS: Analyses of presenting and final VA, using "severe vision loss" (VA ≤ 6/60) and "no severe loss" (VA > 6/60), were performed. Four hundred fifty-four (64%) patients had VA 

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