Displaying publications 1 - 20 of 33 in total

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  1. Fulltext The Global, Regional, and National Burden of Adult Lip, Oral, and Pharyngeal Cancer in 204 Countries and Territories: A Systematic Analysis for the Global Burden of Disease Study 2019
    GBD 2019 Lip, Oral, and Pharyngeal Cancer Collaborators, Cunha ARD, Compton K, Xu R, Mishra R, Drangsholt MT, et al.
    JAMA Oncol, 2023 Oct 01;9(10):1401-1416.
    PMID: 37676656 DOI: 10.1001/jamaoncol.2023.2960
    IMPORTANCE: Lip, oral, and pharyngeal cancers are important contributors to cancer burden worldwide, and a comprehensive evaluation of their burden globally, regionally, and nationally is crucial for effective policy planning.

    OBJECTIVE: To analyze the total and risk-attributable burden of lip and oral cavity cancer (LOC) and other pharyngeal cancer (OPC) for 204 countries and territories and by Socio-demographic Index (SDI) using 2019 Global Burden of Diseases, Injuries, and Risk Factors (GBD) Study estimates.

    EVIDENCE REVIEW: The incidence, mortality, and disability-adjusted life years (DALYs) due to LOC and OPC from 1990 to 2019 were estimated using GBD 2019 methods. The GBD 2019 comparative risk assessment framework was used to estimate the proportion of deaths and DALYs for LOC and OPC attributable to smoking, tobacco, and alcohol consumption in 2019.

    FINDINGS: In 2019, 370 000 (95% uncertainty interval [UI], 338 000-401 000) cases and 199 000 (95% UI, 181 000-217 000) deaths for LOC and 167 000 (95% UI, 153 000-180 000) cases and 114 000 (95% UI, 103 000-126 000) deaths for OPC were estimated to occur globally, contributing 5.5 million (95% UI, 5.0-6.0 million) and 3.2 million (95% UI, 2.9-3.6 million) DALYs, respectively. From 1990 to 2019, low-middle and low SDI regions consistently showed the highest age-standardized mortality rates due to LOC and OPC, while the high SDI strata exhibited age-standardized incidence rates decreasing for LOC and increasing for OPC. Globally in 2019, smoking had the greatest contribution to risk-attributable OPC deaths for both sexes (55.8% [95% UI, 49.2%-62.0%] of all OPC deaths in male individuals and 17.4% [95% UI, 13.8%-21.2%] of all OPC deaths in female individuals). Smoking and alcohol both contributed to substantial LOC deaths globally among male individuals (42.3% [95% UI, 35.2%-48.6%] and 40.2% [95% UI, 33.3%-46.8%] of all risk-attributable cancer deaths, respectively), while chewing tobacco contributed to the greatest attributable LOC deaths among female individuals (27.6% [95% UI, 21.5%-33.8%]), driven by high risk-attributable burden in South and Southeast Asia.

    CONCLUSIONS AND RELEVANCE: In this systematic analysis, disparities in LOC and OPC burden existed across the SDI spectrum, and a considerable percentage of burden was attributable to tobacco and alcohol use. These estimates can contribute to an understanding of the distribution and disparities in LOC and OPC burden globally and support cancer control planning efforts.

  2. Case of human rabies despite post-exposure prophylaxis (PEP) and complete recovery after intrathecal rabies immunoglobulin (RIG)
    Ing SK, Ng Han Sim B, Lee YH, Ling TY
    BMJ Case Rep, 2023 Sep 04;16(9).
    PMID: 37666566 DOI: 10.1136/bcr-2023-256408
    Rabies, a fatal viral zoonotic disease, has become a public health concern in Sarawak, Malaysia. Despite pre-exposure and post-exposure prophylaxis being available, there has been limited progress in developing treatments for rabies, emphasising the pressing need for productive solutions. We present a laboratory-confirmed human rabies case in which the patient survived without neurological sequelae after receiving intrathecal rabies immunoglobulin.
  3. Fulltext Secondary hemophagocytic lymphohistiocytosis: an unusual complication in disseminated Mycobacterium tuberculosis
    Ing SK, Lee GWC, Leong TS, Lee YH, Lau GYL, Yusof NN, et al.
    Clin Med (Lond), 2023 Jul;23(4):414-416.
    PMID: 37524430 DOI: 10.7861/clinmed.2023-0171
    Tuberculosis-associated hemophagocytic lymphohistiocytosis (TB-HLH) is a rare and life-threatening complication of tuberculosis infection. Early recognition and treatment of TB-HLH is crucial for improving outcomes. Treatment typically involves a combination of antituberculosis therapy and immunosuppressive therapy to control the immune system's overreaction. In this report, we present the case of a 53-year-old ambulance driver who was diagnosed with TB-HLH. His CT scan revealed splenic abscesses, hepatomegaly and bilateral lung consolidation. He subsequently developed multiorgan failure, including acute respiratory distress syndrome (ARDS), transaminitis and bone marrow dysfunction. The clinical course and simultaneous increase in serum ferritin raised the suspicion of HLH. His Hscore was 254, indicating a high probability of hemophagocytic syndrome. TB diagnosis was confirmed by positive endotracheal TB GeneXpert and bone marrow aspiration (BMA) which detected acid-fast bacilli organisms. The patient was promptly started on anti-TB, dexamethasone and IVIG. The patient responded well to treatment and made a full recovery without any lasting complications. This case highlights the importance of promptly recognising HLH and identifying the underlying cause. In critically ill patients, it is crucial not to delay HLH-specific treatment while working up for differential diagnosis.
  4. Fulltext Should I buy or not? Revisiting the concept and measurement of panic buying
    Cham TH, Cheng BL, Lee YH, Cheah JH
    Curr Psychol, 2022 Apr 13.
    PMID: 35431524 DOI: 10.1007/s12144-022-03089-9
    Following various precautionary measures as executed by the government to curb the transmission of COVID-19, erratic changes in the form of temporary lockdowns and movement restrictions have created an emergency phenomenon-panic buying. While such consequence has emerged as a timely and relevant topic, reviewed literature indicate an apparent oversight for portraying panic buying through the perspectives of impulsive and compulsive consumptions. Given the gap in the association between panic buying and consumers' emotional aspects within the context of the COVID-19 pandemic, this study aspires to develop a contemporary measurement that accurately defines panic buying as a research variable. A combined methodology was hereby adopted, with the employment of qualitative inquiries towards the scale development of panic buying. Following this, quantitative data as collected from a total sample of 600 respondents through an online survey was analysed via both SPSS and AMOS statistical software towards scale assessment and hypothesis testing. Obtained findings uncovered the direct significance of both personal (fear, perceived risk, and perceived scarcity) and social (word-of-mouth and social media) factors on panic buying during the pandemic, whilst having indirect significance on the ensuing post-purchase regret. Impulsivity was further confirmed to exert a substantial moderating impact on the correlation between panic consumption and post-purchase emotional distress. Implications of the study are ultimately discussed.
  5. Fulltext Cancer Incidence, Mortality, Years of Life Lost, Years Lived With Disability, and Disability-Adjusted Life Years for 29 Cancer Groups From 2010 to 2019: A Systematic Analysis for the Global Burden of Disease Study 2019
    Global Burden of Disease 2019 Cancer Collaboration, Kocarnik JM, Compton K, Dean FE, Fu W, Gaw BL, et al.
    JAMA Oncol, 2022 Mar 01;8(3):420-444.
    PMID: 34967848 DOI: 10.1001/jamaoncol.2021.6987
    IMPORTANCE: The Global Burden of Diseases, Injuries, and Risk Factors Study 2019 (GBD 2019) provided systematic estimates of incidence, morbidity, and mortality to inform local and international efforts toward reducing cancer burden.

    OBJECTIVE: To estimate cancer burden and trends globally for 204 countries and territories and by Sociodemographic Index (SDI) quintiles from 2010 to 2019.

    EVIDENCE REVIEW: The GBD 2019 estimation methods were used to describe cancer incidence, mortality, years lived with disability, years of life lost, and disability-adjusted life years (DALYs) in 2019 and over the past decade. Estimates are also provided by quintiles of the SDI, a composite measure of educational attainment, income per capita, and total fertility rate for those younger than 25 years. Estimates include 95% uncertainty intervals (UIs).

    FINDINGS: In 2019, there were an estimated 23.6 million (95% UI, 22.2-24.9 million) new cancer cases (17.2 million when excluding nonmelanoma skin cancer) and 10.0 million (95% UI, 9.36-10.6 million) cancer deaths globally, with an estimated 250 million (235-264 million) DALYs due to cancer. Since 2010, these represented a 26.3% (95% UI, 20.3%-32.3%) increase in new cases, a 20.9% (95% UI, 14.2%-27.6%) increase in deaths, and a 16.0% (95% UI, 9.3%-22.8%) increase in DALYs. Among 22 groups of diseases and injuries in the GBD 2019 study, cancer was second only to cardiovascular diseases for the number of deaths, years of life lost, and DALYs globally in 2019. Cancer burden differed across SDI quintiles. The proportion of years lived with disability that contributed to DALYs increased with SDI, ranging from 1.4% (1.1%-1.8%) in the low SDI quintile to 5.7% (4.2%-7.1%) in the high SDI quintile. While the high SDI quintile had the highest number of new cases in 2019, the middle SDI quintile had the highest number of cancer deaths and DALYs. From 2010 to 2019, the largest percentage increase in the numbers of cases and deaths occurred in the low and low-middle SDI quintiles.

    CONCLUSIONS AND RELEVANCE: The results of this systematic analysis suggest that the global burden of cancer is substantial and growing, with burden differing by SDI. These results provide comprehensive and comparable estimates that can potentially inform efforts toward equitable cancer control around the world.

  6. Fulltext Palm Oil Fuel Ash-Based Eco-Friendly Concrete Composite: A Critical Review of the Long-Term Properties
    Amran M, Lee YH, Fediuk R, Murali G, Mosaberpanah MA, Ozbakkaloglu T, et al.
    Materials (Basel), 2021 Nov 22;14(22).
    PMID: 34832474 DOI: 10.3390/ma14227074
    Rapid global infrastructural developments and advanced material science, amongst other factors, have escalated the demand for concrete. Cement, which is an integral part of concrete, binds the various individual solid materials to form a cohesive mass. Its production to a large extent emits many tons of greenhouse gases, with nearly 10% of global carbon (IV) oxide (CO2) emanating from cement production. This, coupled with an increase in the advocacy for environmental sustainability, has led to the development of various innovative solutions and supplementary cementitious materials. These aims to substantially reduce the overall volume of cement required in concrete and to meet the consistently increasing demand for concrete, which is projected to increase as a result of rapid construction and infrastructural development trends. Palm oil fuel ash (POFA), an industrial byproduct that is a result of the incineration of palm oil wastes due to electrical generation in power plants has unique properties, as it is a very reactive materials with robust pozzolanic tendencies, and which exhibits adequate micro-filling capabilities. In this study, a review on the material sources, affecting factors, and durability characteristics of POFA are carefully appraised. Moreover, in this study, a review of correlated literature with a broad spectrum of insights into the likely utilization of POFA-based eco-friendly concrete composites as a green material for the present construction of modern buildings is presented.
  7. Fulltext Phylogenomic Analysis of a 55.1-kb 19-Gene Dataset Resolves a Monophyletic Fusarium that Includes the Fusarium solani Species Complex
    Geiser DM, Al-Hatmi AMS, Aoki T, Arie T, Balmas V, Barnes I, et al.
    Phytopathology, 2021 Jul;111(7):1064-1079.
    PMID: 33200960 DOI: 10.1094/PHYTO-08-20-0330-LE
    Scientific communication is facilitated by a data-driven, scientifically sound taxonomy that considers the end-user's needs and established successful practice. In 2013, the Fusarium community voiced near unanimous support for a concept of Fusarium that represented a clade comprising all agriculturally and clinically important Fusarium species, including the F. solani species complex (FSSC). Subsequently, this concept was challenged in 2015 by one research group who proposed dividing the genus Fusarium into seven genera, including the FSSC described as members of the genus Neocosmospora, with subsequent justification in 2018 based on claims that the 2013 concept of Fusarium is polyphyletic. Here, we test this claim and provide a phylogeny based on exonic nucleotide sequences of 19 orthologous protein-coding genes that strongly support the monophyly of Fusarium including the FSSC. We reassert the practical and scientific argument in support of a genus Fusarium that includes the FSSC and several other basal lineages, consistent with the longstanding use of this name among plant pathologists, medical mycologists, quarantine officials, regulatory agencies, students, and researchers with a stake in its taxonomy. In recognition of this monophyly, 40 species described as genus Neocosmospora were recombined in genus Fusarium, and nine others were renamed Fusarium. Here the global Fusarium community voices strong support for the inclusion of the FSSC in Fusarium, as it remains the best scientific, nomenclatural, and practical taxonomic option available.
  8. Localisation of citrullinated and carbamylated proteins in inflamed gingival tissues from rheumatoid arthritis patients
    Lee YH, Baharuddin NA, Chan SW, Rahman MT, Bartold PM, Sockalingam S, et al.
    Clin Oral Investig, 2021 Mar;25(3):1441-1450.
    PMID: 32656595 DOI: 10.1007/s00784-020-03452-9
    OBJECTIVES: It has been proposed that citrullination and carbamylation occur in the inflamed periodontium and could be the plausible mechanisms for the generation of antigens involved in the development and progression of RA. The purpose of this study was to determine the presence and location of citrullinated and carbamylated proteins in the gingival tissues and compare their abundance in periodontitis (PD) patients with or without RA.

    MATERIALS AND METHODS: Gingival tissue samples of healthy (n = 5), PD with RA (n = 5) and PD without RA (n = 5) were collected. Specimens were formalin fixed, paraffin embedded and sectioned at 4 μm. The tissue sections were analysed for the presence of citrullinated and carbamylated proteins by immunohistochemistry. Semi-quantitative analysis was performed to quantify and compare the protein abundance between groups.

    RESULTS: The number of cells containing citrullinated and carbamylated proteins with higher intensity was markedly increased in gingival tissues from PD with or without RA in comparison with healthy controls.

    CONCLUSION: Inflamed gingival tissue is a potential source of citrullinated and carbamylated proteins other than synovial tissues. The extent to which the local accumulation of these proteins contributes to the pathogenesis of RA needs further elucidation.

    CLINICAL RELEVANCE: If PD is a potential source of post-translationally modified proteins, untreated PD should not be taken lightly in the context of RA. Hence, addressing gingival inflammation should be viewed as an important preventive measure in the general population not only for the progression of periodontal disease but also reducing the risk of developing extra-oral comorbidities.

  9. Fulltext Guidelines for the use and interpretation of assays for monitoring autophagy (4th edition)1
    Klionsky DJ, Abdel-Aziz AK, Abdelfatah S, Abdellatif M, Abdoli A, Abel S, et al.
    Autophagy, 2021 Jan;17(1):1-382.
    PMID: 33634751 DOI: 10.1080/15548627.2020.1797280
    In 2008, we published the first set of guidelines for standardizing research in autophagy. Since then, this topic has received increasing attention, and many scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Thus, it is important to formulate on a regular basis updated guidelines for monitoring autophagy in different organisms. Despite numerous reviews, there continues to be confusion regarding acceptable methods to evaluate autophagy, especially in multicellular eukaryotes. Here, we present a set of guidelines for investigators to select and interpret methods to examine autophagy and related processes, and for reviewers to provide realistic and reasonable critiques of reports that are focused on these processes. These guidelines are not meant to be a dogmatic set of rules, because the appropriateness of any assay largely depends on the question being asked and the system being used. Moreover, no individual assay is perfect for every situation, calling for the use of multiple techniques to properly monitor autophagy in each experimental setting. Finally, several core components of the autophagy machinery have been implicated in distinct autophagic processes (canonical and noncanonical autophagy), implying that genetic approaches to block autophagy should rely on targeting two or more autophagy-related genes that ideally participate in distinct steps of the pathway. Along similar lines, because multiple proteins involved in autophagy also regulate other cellular pathways including apoptosis, not all of them can be used as a specific marker for bona fide autophagic responses. Here, we critically discuss current methods of assessing autophagy and the information they can, or cannot, provide. Our ultimate goal is to encourage intellectual and technical innovation in the field.
  10. Fulltext Fibre-Reinforced Foamed Concretes: A Review
    Amran M, Fediuk R, Vatin N, Lee YH, Murali G, Ozbakkaloglu T, et al.
    Materials (Basel), 2020 Sep 28;13(19).
    PMID: 32998362 DOI: 10.3390/ma13194323
    Foamed concrete (FC) is a high-quality building material with densities from 300 to 1850 kg/m3, which can have potential use in civil engineering, both as insulation from heat and sound, and for load-bearing structures. However, due to the nature of the cement material and its high porosity, FC is very weak in withstanding tensile loads; therefore, it often cracks in a plastic state, during shrinkage while drying, and also in a solid state. This paper is the first comprehensive review of the use of man-made and natural fibres to produce fibre-reinforced foamed concrete (FRFC). For this purpose, various foaming agents, fibres and other components that can serve as a basis for FRFC are reviewed and discussed in detail. Several factors have been found to affect the mechanical properties of FRFC, namely: fresh and hardened densities, particle size distribution, percentage of pozzolanic material used and volume of chemical foam agent. It was found that the rheological properties of the FRFC mix are influenced by the properties of both fibres and foam; therefore, it is necessary to apply an additional dosage of a foam agent to enhance the adhesion and cohesion between the foam agent and the cementitious filler in comparison with materials without fibres. Various types of fibres allow the reduction of by autogenous shrinkage a factor of 1.2-1.8 and drying shrinkage by a factor of 1.3-1.8. Incorporation of fibres leads to only a slight increase in the compressive strength of foamed concrete; however, it can significantly improve the flexural strength (up to 4 times), tensile strength (up to 3 times) and impact strength (up to 6 times). At the same time, the addition of fibres leads to practically no change in the heat and sound insulation characteristics of foamed concrete and this is basically depended on the type of fibres used such as Nylon and aramid fibres. Thus, FRFC having the presented set of properties has applications in various areas of construction, both in the construction of load-bearing and enclosing structures.
  11. Fulltext Consensus survey on pre-procedural safety practices in radiological examinations: a multicenter study in seven Asian regions
    Lee YH, Quek ST, Khong PL, Lee CS, Wu JS, Zhang L, et al.
    Br J Radiol, 2020 Sep;93(1113):20200082.
    PMID: 32584595 DOI: 10.1259/bjr.20200082
    OBJECTIVE: To understand the status of pre-procedural safety practices in radiological examinations at radiology residency training institutions in various Asian regions.

    METHODS: A questionnaire based on the Joint Commission International Accreditation Standards was electronically sent to 3 institutions each in 10 geographical regions across 9 Asian countries. Questions addressing 45 practices were divided into 3 categories. A five-tier scale with numerical scores was used to evaluate safety practices in each institution. Responses obtained from three institutions in the United States were used to validate the execution rate of each surveyed safety practice.

    RESULTS: The institutional response rate was 70.0% (7 Asian regions, 21 institutions). 44 practices (all those surveyed except for the application of wrist tags for identifying patients with fall risks) were validated using the US participants. Overall, the Asian participants reached a consensus on 89% of the safety practices. Comparatively, most Asian participants did not routinely perform three pre-procedural practices in the examination appropriateness topic.

    CONCLUSION: Based on the responses from 21 participating Asian institutions, most routinely perform standard practices during radiological examinations except when it comes to examination appropriateness. This study can provide direction for safety policymakers scrutinizing and improving regional standards of care.

    ADVANCES IN KNOWLEDGE: This is the first multicenter survey study to elucidate pre-procedural safety practices in radiological examinations in seven Asian regions.

  12. Tricistronic expression of MOAP-1, Bax and RASSF1A in cancer cells enhances chemo-sensitization that requires BH3L domain of MOAP-1
    Lee YH, Pang SW, Revai Lechtich E, Shah K, Simon SE, Ponnusamy S, et al.
    J Cancer Res Clin Oncol, 2020 Jul;146(7):1751-1764.
    PMID: 32377840 DOI: 10.1007/s00432-020-03231-9
    PURPOSE: Although important for apoptosis, the signaling pathway involving MOAP-1(Modulator of Apoptosis 1), RASSF1A (RAS association domain family 1A), and Bax (Bcl-2 associated X protein) is likely to be dysfunctional in many types of human cancers due to mechanisms associated with gene mutation and DNA hyper-methylation. The purpose of the present study was to assess the potential impact of generating physiologically relevant signaling pathway mediated by MOAP-1, Bax, and RASSF1A (MBR) in cancer cells and chemo-drug resistant cancer cells.

    METHODS: The tricistronic expression construct that encodes MOAP-1, Bax, and RASSF1A (MBR) or its mutant, MOAP-1∆BH3L, Bax and RASSF1A (MBRX) was expressed from an IRES (Internal Ribosome Entry Site)-based tricistronic expression vector in human breast cancer cells, including MCF-7, MCF-7-CR (cisplatin resistant) and triple negative breast cancer cells, BMET05, for functional characterization through in vitro and in vivo models.

    RESULTS: Transient expression of MBR potently promoted dose-dependent apoptotic signaling and chemo-sensitization in the cancer cells, as evidenced by loss of cell viability, nuclei condensation and Annexin-V positive staining while stable expression of MBR in MCF-7 cells significantly reduced the number of MBR stable clone by 86% and the stable clone exhibited robust chemo-drug sensitivity. In contrast, MBRX stable clone exhibited chemo-drug resistance while transiently over-expressed MOAP-1ΔBH3L inhibited the apoptotic activity of MBR. Moreover, the spheroids derived from the MBR stable clone displayed enhanced chemo-sensitivity and apoptotic activity. In mouse xenograft model, the tumors derived from MBR stable clone showed relatively high level of tumor growth retardation associated with the increase in apoptotic activity, leading to the decreases in both tumor weight and volume.

    CONCLUSIONS: Expression of MBR in cancer cells induces apoptotic cell death with enhanced chemo-sensitization requiring the BH3L domain of MOAP-1. In animal model, the expression of MBR significantly reduces the growth of tumors, suggesting that MBR is a potent apoptotic sensitizer with potential therapeutic benefits for cancer treatment.

  13. Fulltext Correlates of sugar-sweetened beverage consumption of Malaysian preschoolers aged 3 to 6 years
    Foo LH, Lee YH, Suhaida CY, Hills AP
    BMC Public Health, 2020 Apr 25;20(1):552.
    PMID: 32334561 DOI: 10.1186/s12889-020-08461-7
    BACKGROUND: There is little information about the diet, lifestyle and parental characteristics associated with habitual sugar-sweetened beverage (SSB) consumption in Asian children. The aim of the present study was to assess cross-sectional associations between habitual SSB consumption and preschoolers' diet, physical activity, sedentary behaviour as well as parental and child characteristics in Malaysian preschoolers aged 3 to 6 y.

    METHODS: A total of 590 preschoolers, comprising 317 boys and 273 girls were included. Pre-pilot parental questionnaires were used to assess diet, physical activity (PA) and sedentary behaviour practices and anthropometry was assessed in preschoolers and their parents.

    RESULTS: Multiple logistic regression analyses showed that preschoolers with more frequent weekly intake of snacks [OR 2.7; 95% CI, 1.6-4.4; p 

  14. Fulltext Renal Denervation in Asia: Consensus Statement of the Asia Renal Denervation Consortium
    Kario K, Kim BK, Aoki J, Wong AY, Lee YH, Wongpraparut N, et al.
    Hypertension, 2020 Mar;75(3):590-602.
    PMID: 32008432 DOI: 10.1161/HYPERTENSIONAHA.119.13671
    The Asia Renal Denervation Consortium consensus conference of Asian physicians actively performing renal denervation (RDN) was recently convened to share up-to-date information and regional perspectives, with the goal of consensus on RDN in Asia. First- and second-generation trials of RDN have demonstrated the efficacy and safety of this treatment modality for lowering blood pressure in patients with resistant hypertension. Considering the ethnic differences of the hypertension profile and demographics of cardiovascular disease demonstrated in the SYMPLICITY HTN (Renal Denervation in Patients With Uncontrolled Hypertension)-Japan study and Global SYMPLICITY registry data from Korea and Taiwan, RDN might be an effective hypertension management strategy in Asia. Patient preference for device-based therapy should be considered as part of a shared patient-physician decision process. A practical population for RDN treatment could consist of Asian patients with uncontrolled essential hypertension, including resistant hypertension. Opportunities to refine the procedure, expand the therapy to other sympathetically mediated diseases, and explore the specific effects on nocturnal and morning hypertension offer a promising future for RDN. Based on available evidence, RDN should not be considered a therapy of last resort but as an initial therapy option that may be applied alone or as a complementary therapy to antihypertensive medication.
  15. Zinc(II) salphen complex-based fluorescence optical sensor for biogenic amine detection
    Sahudin MA, Su'ait MS, Tan LL, Lee YH, Abd Karim NH
    Anal Bioanal Chem, 2019 Sep;411(24):6449-6461.
    PMID: 31392436 DOI: 10.1007/s00216-019-02025-4
    Biogenic amines have attracted interest among researchers because of their importance as biomarkers in determining the quality of food freshness in the food industry. A rapid and simple technique that is able to detect biogenic amines is needed. In this work, a new optical sensing material for one of the biogenic amines, histamine, based on a new zinc(II) salphen complex was developed. The binding of zinc(II) complexes without an electron-withdrawing group (complex 1) and with electron-withdrawing groups (F, complex 2; Cl, complex 3) to histamine resulted in enhancement of fluorescence. All complexes exhibited high affinity for histamine [binding constant of (7.14 ± 0.80) × 104, (3.33 ± 0.03) × 105, and (2.35 ± 0.14) × 105 M-1, respectively]. Complex 2 was chosen as the sensing material for further development of an optical sensor for biogenic amines in the following step since it displayed enhanced optical properties in comparison with complexes 1 and 3. The optical sensor for biogenic amines used silica microparticles as the immobilisation support and histamine as the analyte. The optical sensor had a limit of detection for histamine of 4.4 × 10-12 M, with a linear working range between 1.0 × 10-11 and 1.0 × 10-6 M (R2 = 0.9844). The sensor showed good reproducibility, with a low relative standard deviation (5.5 %). In addition, the sensor exhibited good selectivity towards histamine and cadaverine over other amines, such as 1,2-phenylenediamine, triethylamine, and trimethylamine. Recovery and real sample studies suggested that complex 2 could be a promising biogenic amine optical sensing material that can be applied in the food industry, especially in controlling the safety of food for it to remain fresh and healthy for consumption.
  16. Purification of lysozyme from chicken egg white using nanofiber membrane immobilized with Reactive Orange 4 dye
    Ng IS, Song CP, Ooi CW, Tey BT, Lee YH, Chang YK
    Int J Biol Macromol, 2019 Aug 01;134:458-468.
    PMID: 31078593 DOI: 10.1016/j.ijbiomac.2019.05.054
    Nanofiber membrane chromatography integrates liquid membrane chromatography and nanofiber filtration into a single-step purification process. Nanofiber membrane can be functionalised with affinity ligands for promoting binding specificity of membrane. Dye molecules are a good affinity ligand for nanofiber membrane due to their low cost and high binding affinity. In this study, a dye-affinity nanofiber membrane (P-Chitosan-Dye membrane) was prepared by using polyacrylonitrile nanofiber membrane modified with chitosan molecules and immobilized with dye molecules. Reactive Orange 4, commercially known as Procion Orange MX2R, was found to be the best dye ligand for membrane chromatography. The binding capacity of P-Chitosan-Dye membrane for lysozyme was investigated under different operating conditions in batch mode. Furthermore, desorption of lysozyme using the P-Chitosan-Dye membrane was evaluated systematically. The recovery percentage of lysozyme was found to be ~100%. The optimal conditions obtained from batch-mode study were adopted to develop a purification process to separate lysozyme from chicken egg white. The process was operated continuously using the membrane chromatography and the characteristic of the breakthrough curve was evaluated. At a lower flow rate (i.e., 0.1 mL/min), the total recovery of lysozyme and purification factor of lysozyme were 98.59% and 56.89 folds, respectively.
  17. Potential mechanisms linking periodontitis to rheumatoid arthritis
    Lee YH, Lew PH, Cheah CW, Rahman MT, Baharuddin NA, Vaithilingam RD
    J Int Acad Periodontol, 2019 07 01;21(3):99-110.
    PMID: 31473702
    Periodontitis (PD), a chronic inflammatory disease which results in irreversible attachment loss, bone destruction and tooth loss, is a major oral health problem. Rheumatoid arthritis (RA), with a global prevalence of 1%, is an autoimmune disease characterized as a chronic inflammatory disorder leading to synovial inflammation and destruction of cartilage and bone. Studies have reported an association between PD and RA whereby PD is reportedly more severe in patients with established RA. Justification for the plausible link between both conditions is based on shared characteristics and pathogenic similarities with regard to risk factors, immunogenetics and tissue destruction pathways. The search for the possible mechanism linking PD to RA continues as it can play an important role in enabling early intervention in the form of prevention and treatment of infection. This will ultimately improve patients' oral health related quality of life and reduce societal burden related to increased patient discomfort and treatment costs. The current review provides an update on the cellular and molecular events that have thus far explained the link.
  18. Fulltext A New Sensor for Methyl Paraben Using an Electrode Made of a Cellulose Nanocrystal-Reduced Graphene Oxide Nanocomposite
    Wan Khalid WEF, Mat Arip MN, Jasmani L, Lee YH
    Sensors (Basel), 2019 Jun 18;19(12).
    PMID: 31216625 DOI: 10.3390/s19122726
    A new cellulose nanocrystal-reduced graphene oxide (CNC-rGO) nanocomposite was successfully used for mediatorless electrochemical sensing of methyl paraben (MP). Fourier-transform infrared spectroscopy (FTIR) and field-emission scanning electron microscopy (FESEM) studies confirmed the formation of the CNC-rGO nanocomposite. Cyclic voltammetry (CV) studies of the nanocomposite showed quasi-reversible redox behavior. Differential pulse voltammetry (DPV) was employed for the sensor optimization. Under optimized conditions, the sensor demonstrated a linear calibration curve in the range of 2 × 10-4-9 × 10-4 M with a limit of detection (LOD) of 1 × 10-4 M. The MP sensor showed good reproducibility with a relative standard deviation (RSD) of about 8.20%. The sensor also exhibited good stability and repeatability toward MP determinations. Analysis of MP in cream samples showed recovery percentages between 83% and 106%. Advantages of this sensor are the possibility for the determination of higher concentrations of MP when compared with most other reported sensors for MP. The CNC-rGO nanocomposite-based sensor also depicted good reproducibility and reusability compared to the rGO-based sensor. Furthermore, the CNC-rGO nanocomposite sensor showed good selectivity toward MP with little interference from easily oxidizable species such as ascorbic acid.
  19. Fulltext Median nerve stimulation induces analgesia via orexin-initiated endocannabinoid disinhibition in the periaqueductal gray
    Chen YH, Lee HJ, Lee MT, Wu YT, Lee YH, Hwang LL, et al.
    Proc Natl Acad Sci U S A, 2018 11 06;115(45):E10720-E10729.
    PMID: 30348772 DOI: 10.1073/pnas.1807991115
    Adequate pain management remains an unmet medical need. We previously revealed an opioid-independent analgesic mechanism mediated by orexin 1 receptor (OX1R)-initiated 2-arachidonoylglycerol (2-AG) signaling in the ventrolateral periaqueductal gray (vlPAG). Here, we found that low-frequency median nerve stimulation (MNS) through acupuncture needles at the PC6 (Neiguan) acupoint (MNS-PC6) induced an antinociceptive effect that engaged this mechanism. In mice, MNS-PC6 reduced acute thermal nociceptive responses and neuropathy-induced mechanical allodynia, increased the number of c-Fos-immunoreactive hypothalamic orexin neurons, and led to higher orexin A and lower GABA levels in the vlPAG. Such responses were not seen in mice with PC6 needle insertion only or electrical stimulation of the lateral deltoid, a nonmedian nerve-innervated location. Directly stimulating the surgically exposed median nerve also increased vlPAG orexin A levels. MNS-PC6-induced antinociception (MNS-PC6-IA) was prevented by proximal block of the median nerve with lidocaine as well as by systemic or intravlPAG injection of an antagonist of OX1Rs or cannabinoid 1 receptors (CB1Rs) but not by opioid receptor antagonists. Systemic blockade of OX1Rs or CB1Rs also restored vlPAG GABA levels after MNS-PC6. A cannabinoid (2-AG)-dependent mechanism was also implicated by the observations that MNS-PC6-IA was prevented by intravlPAG inhibition of 2-AG synthesis and was attenuated in Cnr1-/- mice. These findings suggest that PC6-targeting low-frequency MNS activates hypothalamic orexin neurons, releasing orexins to induce analgesia through a CB1R-dependent cascade mediated by OX1R-initiated 2-AG retrograde disinhibition in the vlPAG. The opioid-independent characteristic of MNS-PC6-induced analgesia may provide a strategy for pain management in opioid-tolerant patients.
  20. An ultrasensitive hollow-silica-based biosensor for pathogenic Escherichia coli DNA detection
    Ariffin EY, Lee YH, Futra D, Tan LL, Karim NHA, Ibrahim NNN, et al.
    Anal Bioanal Chem, 2018 Mar;410(9):2363-2375.
    PMID: 29504083 DOI: 10.1007/s00216-018-0893-1
    A novel electrochemical DNA biosensor for ultrasensitive and selective quantitation of Escherichia coli DNA based on aminated hollow silica spheres (HSiSs) has been successfully developed. The HSiSs were synthesized with facile sonication and heating techniques. The HSiSs have an inner and an outer surface for DNA immobilization sites after they have been functionalized with 3-aminopropyltriethoxysilane. From field emission scanning electron microscopy images, the presence of pores was confirmed in the functionalized HSiSs. Furthermore, Brunauer-Emmett-Teller (BET) analysis indicated that the HSiSs have four times more surface area than silica spheres that have no pores. These aminated HSiSs were deposited onto a screen-printed carbon paste electrode containing a layer of gold nanoparticles (AuNPs) to form a AuNP/HSiS hybrid sensor membrane matrix. Aminated DNA probes were grafted onto the AuNP/HSiS-modified screen-printed electrode via imine covalent bonds with use of glutaraldehyde cross-linker. The DNA hybridization reaction was studied by differential pulse voltammetry using an anthraquinone redox intercalator as the electroactive DNA hybridization label. The DNA biosensor demonstrated a linear response over a wide target sequence concentration range of 1.0×10-12-1.0×10-2 μM, with a low detection limit of 8.17×10-14 μM (R2 = 0.99). The improved performance of the DNA biosensor appeared to be due to the hollow structure and rough surface morphology of the hollow silica particles, which greatly increased the total binding surface area for high DNA loading capacity. The HSiSs also facilitated molecule diffusion through the silica hollow structure, and substantially improved the overall DNA hybridization assay. Graphical abstract Step-by-step DNA biosensor fabrication based on aminated hollow silica spheres.
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