Displaying publications 1 - 20 of 85 in total

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  1. Teoh SL, Amarjeet K
    Med J Malaysia, 1993 Dec;48(4):410-5.
    PMID: 8183164
    A retrospective study of 95 patients with retinal vein occlusion was carried out to determine the clinical presentation and pattern of distribution in the local Malaysian population. There was no significant difference found in its distribution with regards to sex. In comparing branch retinal vein occlusion with central retinal vein occlusion, no significant differences were found in its racial distribution. Branch retinal vein occlusion occurred more commonly among the older patients whereas the converse is true for central retinal vein occlusion. Reduced vision represents the commonest mode of presentation. Hypertension, diabetes mellitus, hyperlipidaemia and haematological disorders are important associated systemic conditions.
  2. Teoh SL, Das S
    Curr Drug Targets, 2017 Nov 30;18(16):1880-1892.
    PMID: 27628948 DOI: 10.2174/1389450117666160907153338
    BACKGROUND: The incidence of lung cancers has increased globally. Increased exposure to tobacco, passive smoking, less consumption of vegetables and fruits and occupational exposure to asbestos, arsenic and chromium are the main risk factors. The pathophysiology of lung cancer is complex and not well understood. Various microRNAs, genes and pathways are associated with lung cancers. The genes involved in lung cancers produce proteins involved in cell growth, differentiation, different cell cycles, apoptosis, immune modulation, tumor spread and progression. The Hippo pathway (also known as the Salvador-Warts-Hippo pathway) is the latest emerging concept in cancers. The Hippo pathway plays an important role in controlling the size of the tissue and organ by virtue of its action on cell proliferation and apoptosis.

    OBJECTIVE: In the present review, we highlight the mammalian Hippo pathway, role of its core members, its upstream regulators, downstream effectors and the resistance cases in lung cancers.

    RESULTS: Specific interaction of Mer with cell surface hyaluronan receptor CD44 is vital in cell contact inhibition, thereby activating Hippo pathway. Both transcription co-activators YAP and TAZ (also known as WWTR1, being homologs of Drosophila Yki) are important regulators of proliferation and apoptosis, and serve as major downstream effectors of the Hippo pathway. Mutation of NF2, the upstream regulator of Hippo pathway is linked to the cancers.

    CONCLUSION: Targeting YAP and TAZ may be important for future drug delivery and treatment.

  3. Teoh SL, Das S
    Tumour Biol., 2016 Nov;37(11):14363-14380.
    PMID: 27623943
    Obesity continues to be a major global problem. Various cancers are related to obesity and proper understanding of their aetiology, especially their molecular tumour biology is important for early diagnosis and better treatment. Genes play an important role in the development of obesity. Few genes such as leptin, leptin receptor encoded by the db (diabetes), pro-opiomelanocortin, AgRP and NPY and melanocortin-4 receptors and insulin-induced gene 2 were linked to obesity. MicroRNAs control gene expression via mRNA degradation and protein translation inhibition and influence cell differentiation, cell growth and cell death. Overexpression of miR-143 inhibits tumour growth by suppressing B cell lymphoma 2, extracellular signal-regulated kinase-5 activities and KRAS oncogene. Cancers of the breast, uterus, renal, thyroid and liver are also related to obesity. Any disturbance in the production of sex hormones and insulin, leads to distortion in the balance between cell proliferation, differentiation and apoptosis. The possible mechanism linking obesity to cancer involves alteration in the level of adipokines and sex hormones. These mediators act as biomarkers for cancer progression and act as targets for cancer therapy and prevention. Interestingly, many anti-cancerous drugs are also beneficial in treating obesity and vice versa. We also reviewed the possible link in the mechanism of few drugs which act both on cancer and obesity. The present review may be important for molecular biologists, oncologists and clinicians treating cancers and also pave the way for better therapeutic options.
  4. Teoh SL, Das S
    Curr Pharm Des, 2017;23(12):1845-1859.
    PMID: 28231756 DOI: 10.2174/1381612822666161027120043
    The incidence and mortality due to breast cancer is increasing worldwide. There is a constant quest to know the underlying molecular biology of breast cancer in order to arrive at diagnosis and plan better treatment options. MicroRNAs (miRNAs) are small non-coding and single stranded RNAs which influence the gene expression and physiological condition in any tumor. The miRNAs may act on different pathways in various cancers. Recently, there are research reports on various miRNAs being linked to breast cancers. The important miRNAs associated with breast cancers include miR-21, miR-155, miR-27a, miR-205, miR-145 and miR-320a. In the present review we discuss the role of miRNAs in breast cancer, its importance as diagnostic markers, prognosis and metastasis markers. We also highlight the role of miRNAs with regard to resistance to few anticancerous drugs such as Tamoxifen and Trastuzumab. The role of miRNA in resistance to treatment is one of the core issues discussed in the present review. Much information on the miRNA roles is available particularly in the neoadjuvant chemotherapy setting, because this protocol allows the rapid association of miRNA expression with the treatment response. This review opens the door for designing better therapeutic options in drug resistance cases in breast cancer.
  5. Teoh SL, Das S
    Curr Drug Targets, 2018;19(2):128-143.
    PMID: 28294046 DOI: 10.2174/1389450118666170309143419
    BACKGROUND: The Notch pathway is an evolutionarily conserved, intercellular signalling system which is present in all multicellular organisms and mammals. The Notch pathway plays an important role in the embryonic development as it controls cell proliferation, cell differentiation and binary cell fate decisions.

    OBJECTIVE: In the present review, we highlight the Notch signalling pathway components i.e. Notch receptors, ligands, effector, and their regulators. We also discuss the tumor biology of the Notch pathway involved in various cancers.

    RESULTS: Interestingly, the Notch signalling pathway is dysregulated in many cancers. Notch may serve as oncogene or tumor suppressor and plays an important role in cancers of the liver, pancreas, endometrium of uterus, ovary, prostate, bladder and colon. The activation of Notch pathway plays a vital role in the progression of some cancer. In addition, Notch pathway activation was also shown to drive chemoresistance in cancer, as well. Chemotherapeutically, combined NOTCH1 inhibitor synergistically attenuated chemotherapy-enriched cancer stem cell population both in vitro and in vivo. This may prove to be beneficial in the treatment of cancer.

    CONCLUSION: The Notch inhibitors possess anti-proliferative effects on cancer, thereby serving as a new treatment for cancer.

  6. Laitiff AA, Teoh SL, Das S
    Clin Ter, 2010;161(4):359-64.
    PMID: 20931161
    The healing of wound is a complex process which requires the interactions of different cells and extracellular molecules. The normal wound healing process can be divided into four overlapping phases i.e. haemostasis, inflammation, proliferation and remodeling. In diseased condition like diabetes mellitus, the wound healing process is grossly impaired, resulting in chronic wounds which fail to heal. In the past decades, several researchers have tested various traditional medicines obtained from the plants for their wound healing properties. Such traditional plants are Aloe vera, Calotropis procera, Portulaca oleracea, Acalypha langiana, Plagiochasma appendiculatum and Momordica charantia. Perhaps one of the most popular and easily available plant is Momordica charantia (bitter gourd). The present article presents an extensive review on the impaired wound healing process in diabetes mellitus and highlights the use of traditional medicines in diabetic wounds.
  7. Teoh SL, Latiff AA, Das S
    Clin Exp Dermatol, 2009 Oct;34(7):815-22.
    PMID: 19508570 DOI: 10.1111/j.1365-2230.2008.03117.x
    Momordica charantia (MC; bitter gourd) is a traditional herb commonly used for its antidiabetic, antioxidant, contraceptive and antibacterial properties. It is also used for the rapid healing of wounds.
  8. Teoh SL, Ogawa S, Parhar IS
    J. Chem. Neuroanat., 2015 Dec;70:20-32.
    PMID: 26571427 DOI: 10.1016/j.jchemneu.2015.10.004
    Metallothionein (MT) is a small cysteine-rich heavy metal-binding protein involved in metal homeostasis, detoxification and free radical-scavenging. MT is ubiquitously expressed in several tissues, but its role in the central nervous system is not well understood. In this study, we identified two MT homologous genes (mt2 and smtb) in the zebrafish. Digoxigenin-in situ hybridization showed the expression of mt2 and smtb genes in the ventricular layers in the telencephalon, diencephalon, mesencephalon and rhombencephalon, most of which are cell proliferating regions in the brain of zebrafish. Cellular characteristics of MT genes expressing cells were examined by double-labelling with markers for neurons (HuC/D) and astrocytes (glial fibrillary acidic protein, GFAP and S100 protein) and cell proliferation marker (PCNA). mt2 and smtb mRNAs are expressed in neurons and not in astrocytes, and they were co-localized with PCNA. These results suggest that mt2 and smtb may play an important role in neurogenesis and neuroprotection.
  9. Chakraborty C, Teoh SL, Das S
    Curr Drug Targets, 2017;18(14):1653-1663.
    PMID: 27231109 DOI: 10.2174/1389450117666160527142321
    BACKGROUND: The present era is fast experiencing rapid innovation in the genome-editing technology. CRISPR Cas9-mediated targeted genetic manipulation is an easy, cost-effective and scalable method. As a result, it can be used for a broad range of targeted genome engineering.

    OBJECTIVE: The main objective of the present review is to highlight the structural signature, classification, its mechanism and application from basic science to medicine and future challenges for this genome editing tool kit.

    RESULTS: The present review provides a brief description of the recent development of CRISPR-Cas9 genome editing technology. We discuss the paradigms shift for this next generation genome editing technology, CRISPR. The CRISPR structural significance, classification and its different applications are also being discussed. We portray the future challenges for this extraordinary genome in vivo editing tool. We also highlight the role of CRISPR genome editing in curing many diseases.

    CONCLUSION: Scientists and researchers are constantly looking one genome editing tool that is competent, simple and low-cost assembly of nucleases. It can target any particular site without any off-target mutations in the genome. The CRISPR-Cas9 has all of the above characteristics. The genome engineering technology may be a strong and inspiring technology meant for the next generation of drug development.

  10. Teoh SL, Letchumanan V, Lee LH
    Front Psychol, 2021;12:633319.
    PMID: 33716901 DOI: 10.3389/fpsyg.2021.633319
    Objective: Mindfulness-based intervention (MBI) has been proposed to alleviate loneliness and improve social connectedness. Several randomized controlled trials (RCTs) have been conducted to evaluate the effectiveness of MBI. This study aimed to critically evaluate and determine the effectiveness and safety of MBI in alleviating the feeling of loneliness. Methods: We searched Medline, Embase, PsycInfo, Cochrane CENTRAL, and AMED for publications from inception to May 2020. We included RCTs with human subjects who were enrolled in MBI with loneliness as an outcome. The quality of evidence was assessed using Cochrane's Risk of Bias (ROB) tool and Grading of Recommendations Assessment, Development, and Evaluation (GRADE). A random-effects model was used for meta-analysis. Results: Out of 92 articles identified, eight studies involving 815 participants were included in this study. Most (7/8) trials conducted a minimum of 8 weeks of MBI. Most of the trials (5/8) used UCLA-Loneliness Scale. A pooled analysis combining three trials and compared with wait-list showed significant improvement in loneliness score reduction using the UCLA-R scale with MD of -6.33 [95% confidence interval (CI): -9.39, -3.26]. Subgroup analysis with only two Cognitively-Based Compassion Training (CBCT) trials also showed similar MD of -6.05 (95% CI: -9.53, 2.58). The overall quality of evidence (GRADE) was low. Conclusions: Mindfulness intervention with an average length of 8-week duration significantly improved the population's loneliness level with no mental health issue. However, this evidence had a low GRADE level.
  11. Hor SL, Teoh SL, Lim WL
    Curr Drug Targets, 2020;21(5):458-476.
    PMID: 31625473 DOI: 10.2174/1389450120666191017120505
    Parkinson's disease (PD) is the second most prevalent progressive neurodegenerative disorder characterized by the degeneration of dopaminergic neurons in the human midbrain. Various ongoing research studies are competing to understand the pathology of PD and elucidate the mechanisms underlying neurodegeneration. Current pharmacological treatments primarily focused on improving dopamine metabolism in PD patients, despite the side effects of long-term usage. In recent years, it is recognized that oxidative stress-mediated pathways lead to neurodegeneration in the brain, which is associated with the pathophysiology of PD. The importance of oxidative stress is often less emphasized when developing potential therapeutic approaches. Natural plant antioxidants have been shown to mediate the oxidative stress-induced effects in PD, which has gained considerable attention in both in vitro and in vivo studies. Yet, clinical trials on natural polyphenol compounds are limited, restricting the potential use of these compounds as an alternative treatment for PD. Therefore, this review provides an understanding of the oxidative stress-induced effects in PD by elucidating the underlying events contributing to oxidative stress and explore the potential use of polyphenols in improving the oxidative status in PD. Preclinical findings have supported the potential of polyphenols in providing neuroprotection against oxidative stress-induced toxicity in PD. However, limiting factors, such as safety and bioavailability of polyphenols, warrant further investigations so as to make them the potential target for clinical applications in the treatment and management of PD.
  12. Soliman AM, Das S, Teoh SL
    Int J Mol Sci, 2021 Jul 13;22(14).
    PMID: 34299097 DOI: 10.3390/ijms22147470
    Multiple myeloma (MM) is considered to be the second most common blood malignancy and it is characterized by abnormal proliferation and an accumulation of malignant plasma cells in the bone marrow. Although the currently utilized markers in the diagnosis and assessment of MM are showing promising results, the incidence and mortality rate of the disease are still high. Therefore, exploring and developing better diagnostic or prognostic biomarkers have drawn global interest. In the present review, we highlight some of the recently reported and investigated novel biomarkers that have great potentials as diagnostic and/or prognostic tools in MM. These biomarkers include angiogenic markers, miRNAs as well as proteomic and immunological biomarkers. Moreover, we present some of the advanced methodologies that could be utilized in the early and competent diagnosis of MM. The present review also focuses on understanding the molecular concepts and pathways involved in these biomarkers in order to validate and efficiently utilize them. The present review may also help in identifying areas of improvement for better diagnosis and superior outcomes of MM.
  13. Omar NA, Kumar J, Teoh SL
    Neuropeptides, 2022 Jan 07;92:102226.
    PMID: 35030377 DOI: 10.1016/j.npep.2022.102226
    Neurotrophin is a growth factor that regulates the development and repair of the nervous system. From all factors, two pioneer groups, the nerve growth factor (NGF) and brain derived neurotrophic factor (BDNF), have been widely explored for their role in disease pathogenesis and potential use as therapeutic agents. Nonetheless, neurotrophin-3 (NT3) and neurotrophin-4 (NT4) also have promising potential, albeit less popular than their counterparts. This review focuses on the latter two factors and their roles in the pathogenesis of brain disorders and potential therapies. An extensive literature search of NT3 and NT4 with their receptors, the TrkB and TrkC on the nervous system were extracted and analyzed. We found that NT3 and NT4 are not only involved in the pathogenesis of some neurodegenerative diseases, but also have promising therapeutic potential on injury- and vascular-related nervous system disease, neuropsychiatry, neurodegeneration and peripheral nerve diseases. In conclusion, the role of NT3 and NT4 should be further emphasized, and more studies could be explored on the potential use of these neurotrophins in the human study.
  14. Teoh SL, Latiff AA, Das S
    Clin Ter, 2009;160(4):283-6.
    PMID: 19795081
    Aim: Diabetic liver is associated with biochemical, physiological and pathological changes. The aim of the present study was to evaluate the histological changes following administration of Momordica charantia (MC) in the streptozotocin (STZ) induced diabetic rats.

    Materials and methods: Eighteen Sprague-Dawley rats (n=18) were taken for this study. The animals were divided into 3 groups:- non-diabetic (n=6), untreated diabetic (n=6) and diabetic treated with MC extract (n=6). Diabetes was induced in the experimental rats via intravenous injection of streptozotocin (45 mg/kg body weight). MC extract (50 mg/kg body weight) was administered orally to the treated diabetic rats 10 days following induction. The liver tissues were collected on the 10th day following treatment and the histological study was performed using different staining methods which included hematoxylin and eosin (H&E), Verhoeff's van Gieson (VvG) and periodic acid Schiff (PAS).

    Results: The liver of the diabetic rats showed involvement of the hepatocytes with features of inflammation. The portal triad in the diabetic liver showed extensive involvement in terms of accumulation of mucopolysaccharide deposits. Liver damage in the diabetic animals showed features of healing with administration of the MC extract.

    Conclusions: The MC extract due to its antioxidant role may be helpful in reversing the changes in the liver in diabetes mellitus.
  15. Teoh SL, Abd Latiff A, Das S
    Rom J Morphol Embryol, 2010;51(1):91-5.
    PMID: 20191126
    Momordica charantia (MC) or bitter gourd is widely known for its antidiabetic properties. The aim of the present study was to observe the protective effect of MC extract on the kidneys of streptozotocin-induced diabetic rats. Eighteen male Sprague-Dawley rats (n=18) weighing 200+/-50 g were taken for the study. The study comprised of three groups i.e. a non-diabetic, diabetic untreated and diabetic treated with MC extract, with each group comprising of six (n=6) rats. Diabetes was induced in the overnight fasted rats by intramuscular injection of streptozotocin (50 mg/kg body weight). The MC extract (50 mg/kg body weight) was administered via oral gavage. Both the kidneys were collected on the tenth day following treatment. Histological study using Verhoeff's van Gieson (VvG) and Periodic Acid-Schiff (PAS) stains were performed. The kidneys of the diabetic rats showed thickening of the basement membrane of the Bowman's capsule, edema and hypercellurarity of the proximal tubules, necrosis and hyaline deposits. These features were found to be reversed when the MC extract was administered to the experimental animals. The MC extract acted as an antioxidant thereby preventing the oxidative damage involved in the diabetic kidney. The administration of MC extract prevents oxidative damage in diabetic nephropathy.
  16. Soliman AM, Teoh SL, Das S
    Curr Pharm Des, 2022 Jan 28.
    PMID: 35088658 DOI: 10.2174/1381612828666220128103725
    Gelatin is obtained via partial denaturation of collagen and is extensively used in various industries. The majority of gelatin utilized globally is derived from a mammalian source. Several health and religious concerns associated with porcine/bovine gelatin were reported. Therefore, gelatin from a marine source is widely being investigated for its efficiency and utilization in a variety of applications as a potential substitute for porcine/bovine gelatin. Although fish gelatin is less durable and possesses lower melting and gelling temperatures compared to mammal-derived gelatin, various modifications are being reported to promote its rheological and functional properties to be efficiently employed. The present review describes in detail the current innovative applications of fish gelatin involving the food industry, drug delivery and possible therapeutic applications. Gelatin bioactive molecules may be utilized as carriers for drug delivery. Due to its versatility, gelatin can be used in different carrier systems, such as microparticles, nanoparticles, fibers and hydrogels. The present review also provides a perspective on the other potential pharmaceutical applications of fish gelatin, such as tissue regeneration, antioxidant supplementation, antihypertensive and anticancer treatments.
  17. Putteeraj M, Fairuz YM, Teoh SL
    CNS Neurol Disord Drug Targets, 2017;16(9):1000-1009.
    PMID: 28782488 DOI: 10.2174/1871527316666170807142311
    BACKGROUND AND OBJECTIVE: Alzheimer's disease (AD) is arguably the largest healthcare issue of our time. AD is thought to be principally the result of an inter-play between the β-amyloid peptide and Tau, and it is driven by several genetic and environmental risk factors. Recent studies have shown that small non-protein-coding microRNA (miRNA) and the associated post-transcriptional gene regulation are important regulators of many neurodegenerative diseases, including AD. We reviewed recent studies identifying various miRNA dysregulated in AD. These miRNAs could play a significant role in the pathophysiology of AD, in both β-amyloid peptide and Tau toxicity.

    CONCLUSION: The identification of dysregulated miRNAs pattern can serve as specific AD biomarkers which may provide the basis for new and effective diagnostic approach. In addition, these miRNAs may represent new targets for pharmaceutical development.

  18. Kumar J, Das S, Teoh SL
    Front Nutr, 2018;5:14.
    PMID: 29541638 DOI: 10.3389/fnut.2018.00014
    Acrylamide (AA) is a water soluble white crystalline solid commonly used in industries. It was listed as an industrial chemical with potential carcinogenic properties. However to date, AA was used to produce polyacrylamide polymer, which was widely used as a coagulant in water treatment; additives during papermaking; grouting material for dams, tunnels, and other underground building constructions. AA in food could be formed during high-temperature cookingviaseveral mechanisms, i.e., formationviaacrylic acid which may be derived from the degradation of lipid, carbohydrates, or free amino acids; formationviathe dehydration/decarboxylation of organic acids (malic acid, lactic acid, and citric acid); and direct formation from amino acids. The big debate is whether this compound is toxic to human beings or not. In the present review, we discuss the formation of AA in food products, its consumption, and possible link to the development of any cancers. We discuss the body enzymatic influence on AA and mechanism of action of AA on hormone, calcium signaling pathways, and cytoskeletal filaments. We also highlight the deleterious effects of AA on nervous system, reproductive system, immune system, and the liver. The present and future mitigation strategies are also discussed. The present review on AA may be beneficial for researchers, food industry, and also medical personnel.
  19. Omar NA, Kumar J, Teoh SL
    Front Neurosci, 2023;17:1236049.
    PMID: 37694115 DOI: 10.3389/fnins.2023.1236049
    INTRODUCTION: Parkinson's disease (PD) is the second most common neurodegenerative disease that severely affects the quality of life of patients and their family members. Exposure to 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) has been shown to reflect behavioral, molecular, and proteomic features of PD. This study aimed to assess the protocol for inducing PD following MPTP injection in adult zebrafish.

    METHODS: Fish were injected with 100 μg/g of MPTP intraperitoneally once or twice and then assessed on days 1 to 30 post-injection.

    RESULTS: Between one-time and two-time injections, there was no significant difference in most locomotor parameters, expressions of tyrosine hydroxylase-2 (th2) and dopamine transporter (dat) genes, and dopaminergic neurons (tyrosine hydroxylase positive, TH+ cells) counts. However, caspase-3 levels significantly differed between one- and two-time injections on the day 1 assessment.

    DISCUSSION: Over a 30-day period, the parameters showed significant differences in swimming speed, total distance traveled, tyrosine hydroxylase-1 (th1) and dat gene expressions, caspase-3 and glutathione protein levels, and TH+ cell counts. Days 3 and 5 showed the most changes compared to the control. In conclusion, a one-time injection of MPTP with delayed assessment on days 3 to 5 is a good PD model for animal studies.

  20. Yap RS, Kumar J, Teoh SL
    PMID: 38279761 DOI: 10.2174/0118715273289222231219094225
    Traumatic brain injury (TBI) is a major global health issue that affects millions of people every year. It is caused by any form of external force, resulting in temporary or permanent impairments in the brain. The pathophysiological process following TBI usually involves excitotoxicity, mitochondrial dysfunction, oxidative stress, inflammation, ischemia, and apoptotic cell death. It is challenging to find treatment for TBI due to its heterogeneous nature, and no therapeutic interventions have been approved thus far. Neurotrophins may represent an alternative approach for TBI treatment because they influence various functional activities in the brain. The present review highlights recent studies on neurotrophins shown to possess neuroprotective roles in TBI. Neurotrophins, specifically brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF) have demonstrated reduced neuronal death, alleviated neuroinflammatory responses and improved neurological functions following TBI via their immunomodulatory, anti-inflammatory and antioxidant properties. Further studies are required to ensure the efficacy and safety of neurotrophins to be used as TBI treatment in clinical settings.
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