Displaying publications 1 - 20 of 47 in total

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  1. Tajunisah I, Wong P, Tan L, Rokiah P, Reddy S
    Int J Ophthalmol, 2011;4(5):519-24.
    PMID: 22553714 DOI: 10.3980/j.issn.2222-3959.2011.05.12
    AIM: To assess the awareness of eye complications and the prevalence of retinopathy, in the first visit to eye clinic, among type 2 diabetic patients attending a tertiary medical centre in Kuala Lumpur, Malaysia.
    METHODS: An investigator-administered questionnaire was given to 137 patients with diabetes undergoing first time eye screening in the eye clinic. This was followed by a detailed fundus examination by a senior ophthalmologist to assess for presence of retinopathy.
    RESULTS: Almost 86% of respondents were aware of diabetic eye complications, especially in patients who had achieved tertiary educational level (96.3%). The majority of the patients (78.8%) were referred by their physicians and only 20.4% came on their own initiative. Many of the patients (43.8%) did not know how frequent they should go for an eye check-up and 72.3% did not know what treatments were available. Lack of understanding on diabetic eye diseases (68.6%) was the main barrier for most patients for not coming for eye screening earlier. Despite a high level of awareness, only 21.9% had recorded HbA1c level of <6.5% while 31.4% were under the erroneous assumption of having a good blood sugar control. A total of 29.2% had diabetic retinopathy in their first visit eye testing.
    CONCLUSION: In the present study, 29.2% of type 2 diabetic patients had retinopathy in their first time eye testing. Although the awareness of diabetic eye complications was high among first time eye screening patients, the appropriate eye care-seeking behavior was comparatively less and should be rectified to prevent the rise of this sight threatening eye disease.
    KEYWORDS: awa-reness; diabetic retinopathy; eye complications; eye screening
    Study site: Eye clinic, University Malaya Medical Centre (UMMC), Kuala Lumpur, Malaysia
  2. Tan KH, Tan LT, Nishida R
    J Chem Ecol, 2006 Nov;32(11):2429-41.
    PMID: 17082990 DOI: 10.1007/s10886-006-9154-4
    It is widely believed that most orchid flowers attract insects by using deception or chemical rewards in the form of nectar. Flowers of Bulbophyllum vinaceum produce a large array of phenylpropanoids that lure tephritid fruit fly males and also act as floral reward, which the flies subsequently convert to pheromone components. The major floral volatile components identified are methyl eugenol (ME), trans-coniferyl alcohol (CF), 2-allyl-4,5-dimethoxphenol (DMP), and trans-3,4-dimethoxycinnamyl acetate, whereas the minor components are eugenol, euasarone, trans-3,4-dimethoxy cinnamyl alcohol, and cis-coniferyl alcohol. Among the various floral parts, the lip (which is held in a closed position up against the sexual organs) has the highest concentration of the major compounds. An attracted male fly normally lands on one of the petals before climbing up onto and forcing the "spring loaded" floral lip into the open position, hence exposing the floral sexual organs. The architecture and location of chemical attractants of the lip compel the fly to align itself along the lip's longitudinal axis in a precise manner. As the fly laps up the compounds and moves towards the base of the lip, it passes the point of imbalance causing the lip to spring back to its normal closed position. The fly is catapulted headfirst into the column cavity, and its dorsum strikes the protruding sticky base of the hamulus and adheres to it. The momentum of the fly and the structural morphology of the long stiff hamulus act to pry out the pollinia from its anther cover. Hence, the pollinarium (pollinia + hamulus) is detached from the flower and adhered to the fly's dorsum. In this unique mutualistic association, both species receive direct reproductive benefits--the flower's pollinarium is transported for cross pollination, and the fly is offered a bouquet of phenylpropanoids (synomone) that it consumes, converts, and/or sequesters as sex pheromonal components, thus enhancing sexual attraction and mating success.
  3. Tan LT, Chan KG, Lee LH, Goh BH
    Front Microbiol, 2016;7:79.
    PMID: 26903962 DOI: 10.3389/fmicb.2016.00079
    In response to the increased seafood demand from the ever-going human population, aquaculture has become the fastest growing animal food-producing sector. However, the indiscriminate use of antibiotics as a biological control agents for fish pathogens has led to the emergence of antibiotic resistance bacteria. Probiotics are defined as living microbial supplement that exert beneficial effects on hosts as well as improvement of environmental parameters. Probiotics have been proven to be effective in improving the growth, survival and health status of the aquatic livestock. This review aims to highlight the genus Streptomyces can be a good candidate for probiotics in aquaculture. Studies showed that the feed supplemented with Streptomyces could protect fish and shrimp from pathogens as well as increase the growth of the aquatic organisms. Furthermore, the limitations of Streptomyces as probiotics in aquaculture is also highlighted and solutions are discussed to these limitations.
  4. Letchumanan V, Pusparajah P, Tan LT, Yin WF, Lee LH, Chan KG
    Front Microbiol, 2015;6:1417.
    PMID: 26697003 DOI: 10.3389/fmicb.2015.01417
    High consumer demand for shellfish has led to the need for large-scale, reliable shellfish supply through aquaculture or shellfish farming. However, bacterial infections which can spread rapidly among shellfish poses a major threat to this industry. Shellfish farmers therefore often resort to extensive use of antibiotics, both prophylactically and therapeutically, in order to protect their stocks. The extensive use of antibiotics in aquaculture has been postulated to represent a major contributing factor in the rising incidence of antimicrobial resistant pathogenic bacteria in shellfish. This study aimed to investigate the incidence of pathogenic Vibrio parahaemolyticus and determine the antibiotic resistance profile as well as to perform plasmid curing in order to determine the antibiotic resistance mediation. Based on colony morphology, all 450 samples tested were positive for Vibrio sp; however, tox-R assay showed that only 44.4% (200/450) of these were V. parahaemolyticus. Out of these 200 samples, 6.5% (13/200) were trh-positive while none were tdh-positive. Antibiotic resistance was determined for all V. parahaemolyticus identified against 14 commonly used antibiotics and the multiple antibiotic resistance index (MAR) was calculated. The isolates demonstrated high resistance to several antibiotics tested- including second and third-line antibiotics- with 88% resistant to ampicillin, 81% to amikacin,70.5% to kanamycin, 73% to cefotaxime, and 51.5% to ceftazidime. The MAR index ranged from 0.00 to 0.79 with the majority of samples having an index of 0.36 (resistant to five antibiotics). Among the 13 trh-positive strains, almost 70% (9/13) demonstrated resistance to 4 or more antibiotics. Plasmid profiling for all V. parahaemolyticus isolates revealed that 86.5% (173/200) contained plasmids - ranging from 1 to 7 plasmids with DNA band sizes ranging from 1.2 kb to greater than 10 kb. 6/13 of the pathogenic V. pathogenic strains contained plasmid. After plasmid curing, the plasmid containing pathogenic strains isolated in our study have chromosomally mediated ampicillin resistance while the remaining resistance phenotypes are plasmid mediated. Overall, our results indicate that while the incidence of pathogenic V. parahaemolyticus in shellfish in Selangor still appears to be at relatively reassuring levels, antibiotic resistance is a real concern and warrants ongoing surveillance.
  5. Tan LT, Ser HL, Yin WF, Chan KG, Lee LH, Goh BH
    Front Microbiol, 2015;6:1316.
    PMID: 26635777 DOI: 10.3389/fmicb.2015.01316
    A Streptomyces strain, MUM256 was isolated from Tanjung Lumpur mangrove soil in Malaysia. Characterization of the strain showed that it has properties consistent with those of the members of the genus Streptomyces. In order to explore the potential bioactivities, extract of the fermented broth culture of MUM256 was prepared with organic solvent extraction method. DPPH and SOD activity were utilized to examine the antioxidant capacity and the results have revealed the potency of MUM256 in superoxide anion scavenging activity in dose-dependent manner. The cytotoxicity of MUM256 extract was determined using cell viability assay against 8 different panels of human cancer cell lines. Among all the tested cancer cells, HCT116 was the most sensitive toward the extract treatment. At the highest concentration of tested extract, the result showed 2.3-, 2.0-, and 1.8-folds higher inhibitory effect against HCT116, HT29, and Caco-2 respectively when compared to normal cell line. This result has demonstrated that MUM256 extract was selectively cytotoxic toward colon cancer cell lines. In order to determine the constituents responsible for its bioactivities, the extract was then subjected to chemical analysis using GC-MS. The analysis resulted in the identification of chemical constituents including phenolic and pyrrolopyrazine compounds which may responsible for antioxidant and anticancer activities observed. Based on the findings of this study, the presence of bioactive constituents in MUM256 extract could be a potential source for the development of antioxidative and chemopreventive agents.
  6. Chan WK, Tan LT, Chan KG, Lee LH, Goh BH
    Molecules, 2016 Apr 28;21(5).
    PMID: 27136520 DOI: 10.3390/molecules21050529
    Nerolidol (3,7,11-trimethyl-1,6,10-dodecatrien-3-ol) is a naturally occurring sesquiterpene alcohol that is present in various plants with a floral odor. It is synthesized as an intermediate in the production of (3E)-4,8-dimethy-1,3,7-nonatriene (DMNT), a herbivore-induced volatile that protects plants from herbivore damage. Chemically, nerolidol exists in two geometric isomers, a trans and a cis form. The usage of nerolidol is widespread across different industries. It has been widely used in cosmetics (e.g., shampoos and perfumes) and in non-cosmetic products (e.g., detergents and cleansers). In fact, U.S. Food and Drug Administration (FDA) has also permitted the use of nerolidol as a food flavoring agent. The fact that nerolidol is a common ingredient in many products has attracted researchers to explore more medicinal properties of nerolidol that may exert beneficial effect on human health. Therefore, the aim of this review is to compile and consolidate the data on the various pharmacological and biological activities displayed by nerolidol. Furthermore, this review also includes pharmacokinetic and toxicological studies of nerolidol. In summary, the various pharmacological and biological activities demonstrated in this review highlight the prospects of nerolidol as a promising chemical or drug candidate in the field of agriculture and medicine.
  7. Tan LT, Davagnanam I, Isa H, Rose GE, Verity DH, Pusey CD, et al.
    Ophthalmology, 2015 Oct;122(10):2125-9.
    PMID: 26233627 DOI: 10.1016/j.ophtha.2015.06.026
    Lacrimal gland involvement in granulomatosis with polyangiitis (GPA) commonly accompanies orbital disease, but occasionally may be the sole presentation preceding any other organ manifestation or systemic disease. Diagnosis of orbital GPA, especially in patients with lacrimal involvement as the initial presentation, can be difficult because of nonspecific clinical features and lack of diagnostic specificity on histologic and antineutrophilic cytoplasmic antibody (ANCA) testing. Orbital GPA can be associated with a high morbidity from potential visual loss or rapid progression of latent systemic disease, making early diagnosis important. The purpose of this study was to describe the clinical and imaging features of patients with lacrimal gland involvement secondary to GPA and to compare them with those of other orbital inflammatory conditions in the lacrimal gland fossa.
  8. Low LE, Tan LT, Goh BH, Tey BT, Ong BH, Tang SY
    Int J Biol Macromol, 2019 Apr 15;127:76-84.
    PMID: 30639596 DOI: 10.1016/j.ijbiomac.2019.01.037
    Stimuli-responsive drug release and controlled delivery play crucial roles in enhancing the therapeutic efficacy and lowering over-dosage induced side effects. In this paper, we report magnetically-triggered drug release and in-vitro anti-colon cancer efficacy of Fe3O4@cellulose nanocrystal (MCNC)-stabilized Pickering emulsions containing curcumin (CUR). The loading efficiency of CUR in the micron-sized (≈7 μm) MCNC-stabilized Pickering emulsions (MCNC-PE) template was found to be 99.35%. The drug release profiles showed that the exposure of MCNC-PE to external magnetic field (EMF) (0.7 T) stimulated the release of bioactive from MCNC-PE achieving 53.30 ± 5.08% of the initial loading over a 4-day period. The MTT assay demonstrated that the CUR-loaded MCNC-PE can effectively inhibits the human colon cancer cells growth down to 18% in the presence of EMF. The formulation also resulted in 2-fold reduction on the volume of the 3-D multicellular spheroids of HCT116 as compared to the control sample. The MCNC particle was found to be non-toxic to brine shrimp up to a concentration of 100 μg/mL. Our findings suggested that the palm-based MCNC-PE could be a promising yet effective colloidal drug delivery system for magnetic-triggered release of bioactive and therapeutics.
  9. Lee JK, Hern Tan LT, Ramadas A, Ab Mutalib NS, Lee LH
    PMID: 32977611 DOI: 10.3390/ijerph17196963
    The mortality rate of very preterm infants with birth weight <1500 g is as high as 15%. The survivors till discharge have a high incidence of significant morbidity, which includes necrotising enterocolitis (NEC), early-onset neonatal sepsis (EONS) and late-onset neonatal sepsis (LONS). More than 25% of preterm births are associated with microbial invasion of amniotic cavity. The preterm gut microbiome subsequently undergoes an early disruption before achieving bacterial maturation. It is postulated that bacterial gut colonisation at birth and postnatal intestinal dysbacteriosis precede the development of NEC and LONS in very preterm infants. In fact, bacterial colonization patterns in preterm infants greatly differ from term infants due to maternal chorioamnionitis, gestational age, delivery method, feeding type, antibiotic exposure and the environment factor in neonatal intensive care unit (NICU). In this regard, this review provides an overview on the gut bacteria in preterm neonates' meconium and stool. More than 50% of preterm meconium contains bacteria and the proportion increases with lower gestational age. Researchers revealed that the gut bacterial diversity is reduced in preterm infants at risk for LONS and NEC. Nevertheless, the association between gut dysbacteriosis and NEC is inconclusive with regards to relative bacteria abundance and between-sample beta diversity indices. With most studies show a disruption of the Proteobacteria and Firmicutes preceding the NEC. Hence, this review sheds light on whether gut bacteria at birth either alone or in combination with postnatal gut dysbacteriosis are associated with mortality and the morbidity of LONS and NEC in very preterm infants.
  10. Wang S, Liu F, Tan KS, Ser HL, Tan LT, Lee LH, et al.
    J Cell Mol Med, 2020 01;24(1):722-736.
    PMID: 31680470 DOI: 10.1111/jcmm.14780
    Evidence demonstrates that M1 macrophage polarization promotes inflammatory disease. Here, we discovered that (R)-salbutamol, a β2 receptor agonist, inhibits and reprograms the cellular metabolism of RAW264.7 macrophages. (R)-salbutamol significantly inhibited LPS-induced M1 macrophage polarization and downregulated expressions of typical M1 macrophage cytokines, including monocyte chemotactic protein-1 (MCP-1), interleukin-1β (IL-1β) and tumour necrosis factor α (TNF-α). Also, (R)-salbutamol significantly decreased the production of inducible nitric oxide synthase (iNOS), nitric oxide (NO) and reactive oxygen species (ROS), while increasing the reduced glutathione (GSH)/oxidized glutathione (GSSG) ratio. In contrast, (S)-salbutamol increased the production of NO and ROS. Bioenergetic profiles showed that (R)-salbutamol significantly reduced aerobic glycolysis and enhanced mitochondrial respiration. Untargeted metabolomics analysis demonstrated that (R)-salbutamol modulated metabolic pathways, of which three metabolic pathways, namely, (a) phenylalanine metabolism, (b) the pentose phosphate pathway and (c) glycerophospholipid metabolism were the most noticeably impacted pathways. The effects of (R)-salbutamol on M1 polarization were inhibited by a specific β2 receptor antagonist, ICI-118551. These findings demonstrated that (R)-salbutamol inhibits the M1 phenotype by downregulating aerobic glycolysis and glycerophospholipid metabolism, which may propose (R)-salbutamol as the major pharmacologically active component of racemic salbutamol for the treatment of inflammatory diseases and highlight the medicinal value of (R)-salbutamol.
  11. Sumitro K, Yong CS, Tan LT, Choo S, Lim CY, Shariman H, et al.
    Malays Fam Physician, 2020;15(2):50-52.
    PMID: 32843946
    The djenkol bean (Archidendron pauciflorum) is a native delicacy in Southeast Asia, though consumption can sometimes lead to djenkolism. Clinical features of djenkolism include acute abdominal pain, hematuria, urinary retention, and acute kidney injury (AKI). The pain can be severe, which often leads to a misdiagnosis of acute abdomen. In this paper, we report the case of an Indonesian migrant with djenkolism. Due to the short history and severity of the abdominal pain, medical professionals suspected acute abdomen and proceeded with a negative exploratory laparotomy. However, djenkolism was suspected once relatives informed the professionals that the patient had consumed djenkol beans hours earlier. The patient recovered through aggressive hydration and urine alkalinization with bicarbonate infusion. We highlight the importance of being aware of this rare cause of AKI, especially in Southeast Asia, in order to provide early diagnoses and prompt treatments.
  12. Wong C, Tan LT, Mujahid A, Lihan S, Wee JLS, Ting LF, et al.
    Lett Appl Microbiol, 2018 Oct;67(4):384-391.
    PMID: 29998586 DOI: 10.1111/lam.13049
    Copper (Cu) tolerance was observed by endophytic fungi isolated from the carnivorous plant Nepenthes ampullaria (collected at an anthropogenically affected site, Kuching city; and a pristine site; Heart of Borneo). The fungal isolates, capable of tolerating Cu up to 1000 ppm (11 isolates in total), were identified through molecular method [internal transcribed spacer 4+5 (ITS4+5); ITS1+NL4; β-tubulin region using Bt2a + Bt2b], and all of them grouped with Diaporthe, Nigrospora, and Xylaria. A Cu biosorption study was then carried out using live and dead biomass of the 11 fungal isolates. The highest biosorption capacity of using live biomass was achieved by fungal isolates Xylaria sp. NA40 (73·26 ± 1·61 mg Cu per g biomass) and Diaporthe sp. NA41 (72·65 ± 2·23 mg Cu per g biomass), NA27 (59·81 ± 1·15 mg Cu per g biomass) and NA28 (56·85 ± 4·23 mg Cu per g biomass). The fungal isolate Diaporthe sp. NA41 also achieved the highest biosorption capacity of 59·33 ± 0·15 mg g-1 using dead biomass. The living biomass possessed a better biosorption capacity than the dead biomass (P 
  13. Tan LT, Chan KG, Pusparajah P, Yin WF, Khan TM, Lee LH, et al.
    BMC Microbiol, 2019 02 13;19(1):38.
    PMID: 30760201 DOI: 10.1186/s12866-019-1409-7
    BACKGROUND: Colon cancer is the third most commonly diagnosed cancer worldwide, with a commensurately high mortality rate. The search for novel antioxidants and specific anticancer agents which may inhibit, delay or reverse the development of colon cancer is thus an area of great interest; Streptomyces bacteria have been demonstrated to be a source of such agents.

    RESULTS: The extract from Streptomyces sp. MUM265- a strain which was isolated and identified from Kuala Selangor mangrove forest, Selangor, Malaysia- was analyzed and found to exhibit antioxidant properties as demonstrated via metal-chelating ability as well as superoxide anion, DPPH and ABTS radical scavenging activities. This study also showed that MUM265 extract demonstrated cytotoxicity against colon cancer cells as evidenced by the reduced cell viability of Caco-2 cell line. Treatment with MUM265 extract induced depolarization of mitochondrial membrane potential and accumulation of subG1 cells in cell cycle analysis, suggesting that MUM265 exerted apoptosis-inducing effects on Caco-2 cells.

    CONCLUSION: These findings indicate that mangrove derived Streptomyces sp. MUM265 represents a valuable bioresource of bioactive compounds for the future development of chemopreventive agents, with particular promise suggested for treatment of colon cancer.

  14. Tan LT, Chan KG, Chan CK, Khan TM, Lee LH, Goh BH
    Biomed Res Int, 2018;2018:4823126.
    PMID: 29805975 DOI: 10.1155/2018/4823126
    Mangrove derived microorganisms constitute a rich bioresource for bioprospecting of bioactive natural products. This study explored the antioxidant potentials of Streptomyces bacteria derived from mangrove soil. Based on 16S rRNA phylogenetic analysis, strain MUM292 was identified as the genus Streptomyces. Strain MUM292 showed the highest 16S rRNA gene sequence similarity of 99.54% with S. griseoruber NBRC12873T. Furthermore, strain MUM292 was also characterized and showed phenotypic characteristics consistent with Streptomyces bacteria. Fermentation and extraction were performed to obtain the MUM292 extract containing the secondary metabolites of strain MUM292. The extract displayed promising antioxidant activities, including DPPH, ABTS, and superoxide radical scavenging and also metal-chelating activities. The process of lipid peroxidation in lipid-rich product was also retarded by MUM292 extract and resulted in reduced MDA production. The potential bioactive constituents of MUM292 extract were investigated using GC-MS and preliminary detection showed the presence of pyrazine, pyrrole, cyclic dipeptides, and phenolic compound in MUM292 extract. This work demonstrates that Streptomyces MUM292 can be a potential antioxidant resource for food and pharmaceutical industries.
  15. Chan CK, Tan LT, Andy SN, Kamarudin MNA, Goh BH, Kadir HA
    Front Pharmacol, 2017;8:397.
    PMID: 28680404 DOI: 10.3389/fphar.2017.00397
    Elephantopus scaber L. (family: Asteraceae) has been traditionally utilized as a folkloric medicine and scientifically shown to exhibit anti-inflammatory activities in various in vivo inflammatory models. Given the lack of study on the effect of E. scaber in neuroinflammation, this study aimed to investigate the anti-neuroinflammatory effect and the underlying mechanisms of ethyl acetate fraction from the leaves of E. scaber (ESEAF) on the release of pro-inflammatory mediators in lipopolysaccharide (LPS)-induced microglia cells (BV-2). Present findings showed that ESEAF markedly attenuated the translocation of NF-κB to nucleus concomitantly with the significant mitigation on the LPS-induced production of NO, iNOS, COX-2, PGE2, IL-1β, and TNF-α. These inflammatory responses were reduced via the inhibition of p38. Besides, ESEAF was shown to possess antioxidant activities evident by the DPPH and SOD scavenging activities. The intracellular catalase enzyme activity was enhanced by ESEAF in the LPS-stimulated BV-2 cells. Furthermore, the formation of ROS induced by LPS in BV-2 cells was reduced upon the exposure to ESEAF. Intriguingly, the reduction of ROS was found in concerted with the activation of Nrf2 and HO-1. It is conceivable that the activation promotes the scavenging power of antioxidant enzymes as well as to ameliorate the inflammatory response in LPS-stimulated BV-2 cells. Finally, the safety profile analysis through oral administration of ESEAF at 2000 mg/kg did not result in any mortalities, adverse effects nor histopathologic abnormalities of organs in mice. Taken altogether, the cumulative findings suggested that ESEAF holds the potential to develop as nutraceutical for the intervention of neuroinflammatory disorders.
  16. Kemung HM, Tan LT, Khan TM, Chan KG, Pusparajah P, Goh BH, et al.
    Front Microbiol, 2018;9:2221.
    PMID: 30319563 DOI: 10.3389/fmicb.2018.02221
    Methicillin-resistant Staphylococcus aureus (MRSA) pose a significant health threat as they tend to cause severe infections in vulnerable populations and are difficult to treat due to a limited range of effective antibiotics and also their ability to form biofilm. These organisms were once limited to hospital acquired infections but are now widely present in the community and even in animals. Furthermore, these organisms are constantly evolving to develop resistance to more antibiotics. This results in a need for new clinically useful antibiotics and one potential source are the Streptomyces which have already been the source of several anti-MRSA drugs including vancomycin. There remain large numbers of Streptomyces potentially undiscovered in underexplored regions such as mangrove, deserts, marine, and freshwater environments as well as endophytes. Organisms from these regions also face significant challenges to survival which often result in the production of novel bioactive compounds, several of which have already shown promise in drug development. We review the various mechanisms of antibiotic resistance in MRSA and all the known compounds isolated from Streptomyces with anti-MRSA activity with a focus on those from underexplored regions. The isolation of the full array of compounds Streptomyces are potentially capable of producing in the laboratory has proven a challenge, we also review techniques that have been used to overcome this obstacle including genetic cluster analysis. Additionally, we review the in vivo work done thus far with promising compounds of Streptomyces origin as well as the animal models that could be used for this work.
  17. Goh JXH, Tan LT, Goh JK, Chan KG, Pusparajah P, Lee LH, et al.
    Cancers (Basel), 2019 Jun 21;11(6).
    PMID: 31234411 DOI: 10.3390/cancers11060867
    The search for effective methods of cancer treatment and prevention has been a continuous effort since the disease was discovered. Recently, there has been increasing interest in exploring plants and fruits for molecules that may have potential as either adjuvants or as chemopreventive agents against cancer. One of the promising compounds under extensive research is nobiletin (NOB), a polymethoxyflavone (PMF) extracted exclusively from citrus peel. Not only does nobiletin itself exhibit anti-cancer properties, but its derivatives are also promising chemopreventive agents; examples of derivatives with anti-cancer activity include 3'-demethylnobiletin (3'-DMN), 4'-demethylnobiletin (4'-DMN), 3',4'-didemethylnobiletin (3',4'-DMN) and 5-demethylnobiletin (5-DMN). In vitro studies have demonstrated differential efficacies and mechanisms of NOB and its derivatives in inhibiting and killing of colon cancer cells. The chemopreventive potential of NOB has also been well demonstrated in several in vivo colon carcinogenesis animal models. NOB and its derivatives target multiple pathways in cancer progression and inhibit several of the hallmark features of colorectal cancer (CRC) pathophysiology, including arresting the cell cycle, inhibiting cell proliferation, inducing apoptosis, preventing tumour formation, reducing inflammatory effects and limiting angiogenesis. However, these substances have low oral bioavailability that limits their clinical utility, hence there have been numerous efforts exploring better drug delivery strategies for NOB and these are part of this review. We also reviewed data related to patents involving NOB to illustrate the extensiveness of each research area and its direction of commercialisation. Furthermore, this review also provides suggested directions for future research to advance NOB as the next promising candidate in CRC chemoprevention.
  18. Lin B, Ser HL, Wang L, Li J, Chan KG, Lee LH, et al.
    Int J Mol Sci, 2023 Feb 28;24(5).
    PMID: 36902078 DOI: 10.3390/ijms24054648
    Matrix metalloproteinase-12 (MMP12), or macrophage metalloelastase, plays important roles in extracellular matrix (ECM) component degradation. Recent reports show MMP12 has been implicated in the pathogenesis of periodontal diseases. To date, this review represents the latest comprehensive overview of MMP12 in various oral diseases, such as periodontitis, temporomandibular joint dysfunction (TMD), orthodontic tooth movement (OTM), and oral squamous cell carcinoma (OSCC). Furthermore, the current knowledge regarding the distribution of MMP12 in different tissues is also illustrated in this review. Studies have implicated the association of MMP12 expression with the pathogenesis of several representative oral diseases, including periodontitis, TMD, OSCC, OTM, and bone remodelling. Although there may be a potential role of MMP12 in oral diseases, the exact pathophysiological role of MMP12 remains to be elucidated. Understanding the cellular and molecular biology of MMP12 is essential, as MMP12 could be a potential target for developing therapeutic strategies targeting inflammatory and immunologically related oral diseases.
  19. Tan CS, Bandak DB, Habeebur-Rahman SP, Tan LT, Lim LLA
    Virol J, 2023 Aug 07;20(1):176.
    PMID: 37550752 DOI: 10.1186/s12985-023-02133-9
    SARS-CoV-2 is a zoonotic betacoronavirus that was first reported at the dawn of 2019 in Wuhan, China and has since spread globally, causing an ongoing pandemic. Anthroponotic transmission was reported early, with confirmed infections reported in 26 species to date, including dogs and cats. However, there is a paucity of reports on the transmission of SARS-CoV-2 to companion animals, and thus, we aimed to estimate the seroprevalence of SARS-CoV-2 in dogs and cats in Sarawak, Malaysia. From August 2022 to 2023, we screened plasma samples of 172 companion animals in Sarawak, Malaysia, using a species-independent surrogate virus neutralization test. Our findings revealed the presence of neutralizing antibodies of SARS-CoV-2 in 24.5% (27/110) of dogs and 24.2% (15/62) of cats. To the best of our knowledge, this is the first report of the seroprevalence of SARS-CoV-2 in companion animals in Malaysia. Our findings emphasize the need for pet owners to distance themselves from their pets when unwell, and a strategy must be in place to monitor SARS-CoV-2 in companion animals to assess the potential impact of the virus on companion animals.
  20. Tan LT, Davagnanam I, Isa H, Taylor SR, Rose GE, Verity DH, et al.
    Ophthalmology, 2014 Jun;121(6):1304-9.
    PMID: 24560566 DOI: 10.1016/j.ophtha.2013.12.003
    Granulomatosis with polyangiitis (GPA), previously Wegener's granulomatosis, requires prompt diagnosis and systemic review to exclude life-threatening disease. However, early diagnosis of orbital GPA may be difficult because anti-neutrophil cytoplasmic antibody (ANCA) and anti-PR3 antibody screening can be negative at presentation and orbital biopsies taken for diagnosis may not show the classic features of GPA. This study was designed to compare GPA with other causes of orbital inflammation and to identify the presenting clinical and imaging features most likely to predict GPA and its systemic spread.
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