Displaying publications 61 - 80 of 101 in total

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  1. Lee SH, Reed-Newman T, Anant S, Ramasamy TS
    Stem Cell Rev Rep, 2020 12;16(6):1185-1207.
    PMID: 32894403 DOI: 10.1007/s12015-020-10031-8
    Quiescence in cancer cells is considered a therapeutic challenge as it confers dormancy in tumour, hence circumventing inherent anti-neoplastic surveillance system and standard-of-care cancer therapeutics including chemotherapy and radiotherapy. Since majority of the therapeutics target actively proliferating cancer cells, cancer cells eventually develop quiescent nature as mechanism of survival and cancer progression under both niche and therapeutic pressures. Quiescence state in cancer cells, eventually, confers resistant and aggressive nature to conventional cancer therapies, resulting in disease progression and relapse. Therefore, targeting quiescent cancer cells or cancer stem cells is a promising therapeutic approach, however an extensive review of the relevant information is needed in order to device an effective therapy. While the evidence of quiescence regulation in CSCs is rather a complex molecular and cellular network, herein, we aim to provide a comprehensive understanding of both intrinsic and extrinsic regulation in association with the function of CSCs. Findings on induction of quiescent state in CSCs population, its regulation at both cellular and molecular level, key molecular regulators, cellular events and processes including potential targets to develop therapeutics are extensively reviewed. This review also highlights the impact of CSC plasticity on quiescence which capturing the key challenge of targeting the cells in this state. Beyond understanding the mechanisms underlying quiescence nature of cancer cells, this review provides insightful perspective and future direction on insight in targeting these populations, hence collapse the tumour dormancy programme in order to eradicate tumour mass as a whole. Capability of CSCs to establish quiescent state as a mechanism of survival during unfavorable conditions, as well as its impact in cancer progression and subsequent relapse, including the potential therapeutic strategy to eradicate this CSCs sub-population in the tumor mass as an effective cancer therapy.
  2. Lee SH, Lee OS, Teo SH, Lee YS
    Gait Posture, 2017 09;57:57-68.
    PMID: 28577508 DOI: 10.1016/j.gaitpost.2017.05.023
    We conducted a meta-analysis to analyze how high tibial osteotomy (HTO) changes gait and focused on the following questions: (1) How does HTO change basic gait variables? (2) How does HTO change the gait variables in the knee joint? Twelve articles were included in the final analysis. A total of 383 knees was evaluated. There were 237 open wedge (OW) and 143 closed wedge (CW) HTOs. There were 4 level II studies and 8 level III studies. All studies included gait analysis and compared pre- and postoperative values. One study compared CWHTO and unicompartmental knee arthroplasty (UKA), and another study compared CWHTO and OWHTO. Five studies compared gait variables with those of healthy controls. One study compared operated limb gait variables with those in the non-operated limb. Gait speed, stride length, knee adduction moment, and lateral thrust were major variables assessed in 2 or more studies. Walking speed increased and stride length was increased or similar after HTO compared to the preoperative value in basic gait variables. Knee adduction moment and lateral thrust were decreased after HTO compared to the preoperative knee joint gait variables. Change in co-contraction of the medial side muscle after surgery differed depending on the degree of frontal plane alignment. The relationship between change in knee adduction moment and change in mechanical axis angle was controversial. Based on our systematic review and meta-analysis, walking speed and stride length increased after HTO. Knee adduction moment and lateral thrust decreased after HTO compared to the preoperative values of gait variables in the knee joint.
  3. Lee SH, Looi CY, Chong PP, Foo JB, Looi QH, Ng CX, et al.
    Curr Stem Cell Res Ther, 2021;16(5):551-562.
    PMID: 32988356 DOI: 10.2174/1574888X15666200928110923
    Mesenchymal Stem Cells (MSCs) are adult stem cells that are gaining worldwide attention for their multi-potential use in tissue engineering-based regenerative medicine. They can be obtained from numerous sources and one of the excellent sources is the dental tissue, such as Stem cells that are extracted from the Human Exfoliated Deciduous teeth (SHED). SHED are considered ideal due to their inherent characteristics, including the capability to proliferate quickly with minimal oncogenesis risk, multipotency capacity and their ability to suppress the immune system. On top of these positive cell traits, SHED are easily accessible with the patient's safety assured, posing less ethical issues and could also provide a sufficient number of cells for prospective clinical uses. This is primarily attributed to their ability to differentiate into multiple cell linages, including osteoblasts, odontoblasts, neuronal cells, adipocytes, as well as endothelial cells. Albeit SHED having a bright future, there still remains an obstacle to develop reliable experimental techniques to retain the long-term regeneration potential of the stem cells for prospective research and clinical applications. Therefore, this review aims to describe the various isolation, expansion and cryopreservation techniques used by researchers in this stem cell field. Optimization of these techniques is crucial to obtain distinct SHED culture with preserved stem cell properties, which enable more reproducible results that will be the key for further stem cell therapy development.
  4. Lee SH, Choi H, Kim KW
    Environ Geochem Health, 2018 Oct;40(5):2119-2129.
    PMID: 29536286 DOI: 10.1007/s10653-018-0087-y
    To develop a novel granular adsorbent to remove arsenic and antimony from water, calcined Mg/Al-layered double-hydroxide (CLDH)-incorporated polyethersulfone (PES) granular adsorbents (PES-LDH) were prepared using a core-shell method having 25% PES in an N,N-dimethylformamide solution. The PES-LDH displayed a spherical hollow shape having a rough surface and the average particle size of 1-2 mm. On the PES-LDH surface, nanosized CLDH (100-150 nm) was successfully immobilized by consolidation between PES and CLDH. The adsorption of Sb(V) by PES-LDH was found to be more favorable than for As(V), with the maximum adsorption capacity of As(V) and Sb(V) being 7.44 and 22.8 mg/g, respectively. The regeneration results indicated that a 0.5 M NaOH and 5 M NaCl mixed solution achieved an 80% regeneration efficiency in As(V) adsorption and desorption. However, the regeneration efficiency of Sb(V) gradually decreased due to its strong binding affinity, even though the PES-LDH showed much higher Sb(V) adsorption efficiency than As(V). This study suggested that PES-LDH could be a promising granular adsorbent for the remediation of As(V) and Sb(V) contained in wastewater.
  5. Lee SH, Jaganath IB, Atiya N, Manikam R, Sekaran SD
    J Food Drug Anal, 2016 10;24(4):855-865.
    PMID: 28911625 DOI: 10.1016/j.jfda.2016.03.010
    Chemotherapies remain far from ideal due to drug resistance; therefore, novel chemotherapeutic agents with higher effectiveness are crucial. The extracts of four Phyllanthus species, namely Phyllanthus niruri, Phyllanthus urinaria, Phyllanthus watsonii, and Phyllanthus amarus, were shown to induce apoptosis and inhibit metastasis of breast carcinoma cells (MCF-7). The main objective of this study was to determine the pathways utilized by these four Phyllanthus species to exert anti-metastatic activities. A cancer 10-pathway reporter was used to investigate the pathways affected by the four Phyllanthus species. Results indicated that these Phyllanthus species suppressed breast carcinoma metastasis and proliferation by suppressing matrix metalloprotein 2 and 9 expression via inhibition of the extracellular signal-related kinase (ERK) pathway. Additionally, inhibition of hypoxia-inducible factor 1-α in the hypoxia pathway caused reduced vascular endothelial growth factor and inducible nitric oxide synthase expression, resulting in anti-angiogenic effects and eventually anti-metastasis. Two-dimensional gel electrophoresis identified numerous proteins suppressed by these Phyllanthus species, including invasion proteins, anti-apoptotic protein, protein-synthesis proteins, angiogenic and mobility proteins, and various glycolytic enzymes. Our results indicated that ERK and hypoxia pathways are the most likely targets of the four Phyllanthus species for the inhibition of MCF-7 metastasis.
  6. Lee SH, Cheah DS, Krishnan MM
    Singapore Med J, 1990 Jun;31(3):217-20.
    PMID: 2392698
    Locally advanced or recurrent carcinoma of the breast poses difficult management problems. These fungating and discharging tumours severely impair the quality of life in these unfortunate patients. We report two cases successfully treated with omental transposition flaps and split skin grafts. The operation is described in detail and the results discussed. This technique was found to be safe, effective and rewarding.
  7. Lee SH, Moorthy R, Nagala S
    Br J Surg, 2022 May 16;109(6):497-502.
    PMID: 35576381 DOI: 10.1093/bjs/znac072
    BACKGROUND: The IDEAL Framework is a scheme for safe implementation and assessment of surgical innovation. The transoral endoscopic thyroidectomy vestibular approach (TOETVA) is a new innovation in thyroid surgery that eliminates the need for a cervical incision. Despite considerable interest and adoption worldwide, significant scepticism remains regarding the outcomes and cost-effectiveness for healthcare systems. The aim of this narrative review was to appraise the available literature and examine whether TOETVA has progressed in line with the IDEAL Framework.

    METHODS: A literature review of PubMed with a focus on historical and landmark studies was undertaken to classify the evidence according to the different stages of the IDEAL Framework.

    RESULTS: Several different transoral approaches were developed by a small of number of surgeon-innovators on animals and cadavers, and subsequently in first-in-human studies. The trivestibular approach emerged as the safest technique, with further refinements of this technique culminating in TOETVA. The basic steps and indications for this technique have been standardized and it is now being replicated by early adopters in many centres worldwide. The development of TOETVA has closely aligned with the IDEAL Framework, and is currently at stage 2B (Exploration).

    CONCLUSION: There is need for multi-institutional collaborations and international registry studies to plan high-quality randomized trials comparing TOETVA with other remote-access approaches and collect long-term follow-up data. In countries where TOETVA has yet to be adopted, the IDEAL Framework will be a useful roadmap for government regulators and professional societies to evaluate, regulate, and provide best practice recommendations for the adoption of this technique.

  8. Lee SH, Yeoh ZX, Sachlin IS, Gazali N, Soelar SA, Foo CY, et al.
    Sci Rep, 2022 02 08;12(1):2111.
    PMID: 35136124 DOI: 10.1038/s41598-022-06029-6
    Alterations in the three chemosensory modalities-smell, taste, and chemesthesis-have been implicated in Coronavirus Disease 2019 (COVID-19), yet emerging data suggest a wide geographic and ethnic variation in the prevalence of these symptoms. Studies on chemosensory disorders in COVID-19 have predominantly focused on Caucasian populations whereas Asians remain understudied. We conducted a nationwide, multicentre cross-sectional study using an online questionnaire on a cohort of RT-PCR-confirmed adult COVID-19 patients in Malaysia between 6 June and 30 November 2020. The aim of our study was to investigate their presenting symptoms and assess their chemosensory function using self-ratings of perceived smell, taste, chemesthesis, and nasal blockage. In this cohort of 498 patients, 41.4% reported smell and/or taste loss when diagnosed with COVID-19, which was the commonest symptom. Blocked nose, loss of appetite, and gastrointestinal disturbances were independent predictors of smell and/or taste loss on multivariate analysis. Self-ratings of chemosensory function revealed a reduction in smell, taste, and chemesthesis across the entire cohort of patients that was more profound among those reporting smell and/or taste loss as their presenting symptom. Perceived nasal obstruction accounted for only a small proportion of changes in smell and taste, but not for chemesthesis, supporting viral disruption of sensorineural mechanisms as the dominant aetiology of chemosensory dysfunction. Our study suggests that chemosensory dysfunction in COVID-19 is more widespread than previously reported among Asians and may be related to the infectivity of viral strains.Study Registration: NMRR-20-934-54803 and NCT04390165.
  9. Lee SH, Ng CX, Wong SR, Chong PP
    Curr Drug Targets, 2023;24(6):484-508.
    PMID: 36999414 DOI: 10.2174/1389450124666230329123409
    MicroRNAs have a plethora of roles in various biological processes in the cells and most human cancers have been shown to be associated with dysregulation of the expression of miRNA genes. MiRNA biogenesis involves two alternative pathways, the canonical pathway which requires the successful cooperation of various proteins forming the miRNA-inducing silencing complex (miRISC), and the non-canonical pathway, such as the mirtrons, simtrons, or agotrons pathway, which bypasses and deviates from specific steps in the canonical pathway. Mature miRNAs are secreted from cells and circulated in the body bound to argonaute 2 (AGO2) and miRISC or transported in vesicles. These miRNAs may regulate their downstream target genes via positive or negative regulation through different molecular mechanisms. This review focuses on the role and mechanisms of miRNAs in different stages of breast cancer progression, including breast cancer stem cell formation, breast cancer initiation, invasion, and metastasis as well as angiogenesis. The design, chemical modifications, and therapeutic applications of synthetic anti-sense miRNA oligonucleotides and RNA mimics are also discussed in detail. The strategies for systemic delivery and local targeted delivery of the antisense miRNAs encompass the use of polymeric and liposomal nanoparticles, inorganic nanoparticles, extracellular vesicles, as well as viral vectors and viruslike particles (VLPs). Although several miRNAs have been identified as good candidates for the design of antisense and other synthetic modified oligonucleotides in targeting breast cancer, further efforts are still needed to study the most optimal delivery method in order to drive the research beyond preclinical studies.
  10. Lee SH, Golinska M, Griffiths JR
    Cells, 2021 Sep 09;10(9).
    PMID: 34572020 DOI: 10.3390/cells10092371
    In solid tumours, cancer cells exist within hypoxic microenvironments, and their metabolic adaptation to this hypoxia is driven by HIF-1 transcription factor, which is overexpressed in a broad range of human cancers. HIF inhibitors are under pre-clinical investigation and clinical trials, but there is evidence that hypoxic cancer cells can adapt metabolically to HIF-1 inhibition, which would provide a potential route for drug resistance. Here, we review accumulating evidence of such adaptions in carbohydrate and creatine metabolism and other HIF-1-independent mechanisms that might allow cancers to survive hypoxia despite anti-HIF-1 therapy. These include pathways in glucose, glutamine, and lipid metabolism; epigenetic mechanisms; post-translational protein modifications; spatial reorganization of enzymes; signalling pathways such as Myc, PI3K-Akt, 2-hyxdroxyglutarate and AMP-activated protein kinase (AMPK); and activation of the HIF-2 pathway. All of these should be investigated in future work on hypoxia bypass mechanisms in anti-HIF-1 cancer therapy. In principle, agents targeted toward HIF-1β rather than HIF-1α might be advantageous, as both HIF-1 and HIF-2 require HIF-1β for activation. However, HIF-1β is also the aryl hydrocarbon nuclear transporter (ARNT), which has functions in many tissues, so off-target effects should be expected. In general, cancer therapy by HIF inhibition will need careful attention to potential resistance mechanisms.
  11. Lee SH, H'ng PS, Peng TL, Lum WC
    Pak J Biol Sci, 2013 Nov 01;16(21):1415-8.
    PMID: 24511759
    The objective of this study is to investigate the feasibility of formaldehyde catcher as termites repellent. Single-layered UF-bonded particleboard was post-treated with formaldehyde catcher and heat respectively. Besides that, some boards were also produced with the formaldehyde catcher was added into the resin during the blending process, called add-in method. Particleboard post-treated with formaldehyde catcher reported the most severe attack. Heat-treated particleboard showed slightly better durability than the control blocks while the add-in catcher showed the best durability among three methods. A valid test was obtained as the termites survived the first week of the test. However, all the termites were found dead at the end of the test.
  12. Lee SH, Brianna
    Pathol Res Pract, 2024 Feb;254:155073.
    PMID: 38218039 DOI: 10.1016/j.prp.2023.155073
    Breast cancer has become the most diagnosed cancer worldwide in 2020 with high morbidity and mortality rates. The alarming increase in breast cancer incidence has sprung many researchers to focus on developing novel screening tests to identify early breast cancer which will allow clinicians to provide timely and effective treatments. With much evidence supporting the notion that the deregulation of miRNAs (a class of non-coding RNA) greatly contributes to cancer initiation and progression, the promising role of miRNAs as cancer biomarkers is gaining traction in the research world. Among the upregulated miRNAs identified in breast carcinogenesis, miR-21 was shown to be significantly expressed in breast cancer tissues and bodily fluids of breast cancer patients. Therein, this review paper aims to provide an overview of breast cancer, the role and significance of miR-21 in breast cancer pathogenesis, and its potential as a breast cancer biomarker. The paper also discusses the current types of tumor biomarkers and their limitations, the presence of miR-21 in extracellular vesicles and plasma, screening methods available for miRNA detection along with some challenges faced in developing diagnostic miR-21 testing for breast cancer to provide readers with a comprehensive outlook based on using miR-21 in clinical settings.
  13. Lee SH, Wong RR, Chin CY, Lim TY, Eng SA, Kong C, et al.
    Proc Natl Acad Sci U S A, 2013 Sep 10;110(37):15067-72.
    PMID: 23980181 DOI: 10.1073/pnas.1311725110
    Burkholderia pseudomallei is a Gram-negative soil bacterium that infects both humans and animals. Although cell culture studies have revealed significant insights into factors contributing to virulence and host defense, the interactions between this pathogen and its intact host remain to be elucidated. To gain insights into the host defense responses to B. pseudomallei infection within an intact host, we analyzed the genome-wide transcriptome of infected Caenorhabditis elegans and identified ∼6% of the nematode genes that were significantly altered over a 12-h course of infection. An unexpected feature of the transcriptional response to B. pseudomallei was a progressive increase in the proportion of down-regulated genes, of which ELT-2 transcriptional targets were significantly enriched. ELT-2 is an intestinal GATA transcription factor with a conserved role in immune responses. We demonstrate that B. pseudomallei down-regulation of ELT-2 targets is associated with degradation of ELT-2 protein by the host ubiquitin-proteasome system. Degradation of ELT-2 requires the B. pseudomallei type III secretion system. Together, our studies using an intact host provide evidence for pathogen-mediated host immune suppression through the destruction of a host transcription factor.
  14. Lee J, Kwak YS, Kim YJ, Kim EJ, Park EJ, Shin Y, et al.
    Psychiatry Investig, 2018 Apr;15(4):336-343.
    PMID: 29669407 DOI: 10.30773/pi.2017.11.08.2
    "Comfort women" refers to young women and girls who were forced into sexual slavery by the Imperial Japanese military during World War II. They were abducted from their homes in countries under Imperial Japanese rule, mostly from Korea, and the rest from China, Philippines, Malaysia, Taiwan, Indonesia, the Netherlands, etc. "Comfort women" endured extreme trauma involving rape, sexual torture, physical abuse, starvation, threats of death, and witnessed many others being tortured and killed. This article reviews all the studies that have investigated the psychiatric or psychosocial sequelae of the survivors of the Japanese military sexual slavery. Most importantly, a recent study which conducted a psychiatric evaluation on the former "comfort women" currently alive in South Korea is introduced. The participants' unmarried rate was relatively high and their total fertility rate was relatively low. Majority of the participants reported having no education and being the low economic status. They showed high current and lifetime prevalence of posttraumatic disorder, major depressive disorder, somatic symptom disorder, social anxiety disorder, panic disorder, and alcohol use disorder. Participants showed high suicidality and majority of the participants still reported being ashamed of being former "comfort women" after all these years. This article high-lights the fact that the trauma has affected the mental health and social functioning of former "comfort women" throughout their lives, and even to the present day.
  15. Lee CH, Khalina A, Lee SH
    Polymers (Basel), 2021 Jan 29;13(3).
    PMID: 33573036 DOI: 10.3390/polym13030438
    Plant fibers have become a highly sought-after material in the recent days as a result of raising environmental awareness and the realization of harmful effects imposed by synthetic fibers. Natural plant fibers have been widely used as fillers in fabricating plant-fibers-reinforced polymer composites. However, owing to the completely opposite nature of the plant fibers and polymer matrix, treatment is often required to enhance the compatibility between these two materials. Interfacial adhesion mechanisms are among the most influential yet seldom discussed factors that affect the physical, mechanical, and thermal properties of the plant-fibers-reinforced polymer composites. Therefore, this review paper expounds the importance of interfacial adhesion condition on the properties of plant-fiber-reinforced polymer composites. The advantages and disadvantages of natural plant fibers are discussed. Four important interface mechanism, namely interdiffusion, electrostatic adhesion, chemical adhesion, and mechanical interlocking are highlighted. In addition, quantifying and analysis techniques of interfacial adhesion condition is demonstrated. Lastly, the importance of interfacial adhesion condition on the performances of the plant fiber polymer composites performances is discussed. It can be seen that the physical and thermal properties as well as flexural strength of the composites are highly dependent on the interfacial adhesion condition.
  16. Lee CH, Padzil FNBM, Lee SH, Ainun ZMA, Abdullah LC
    Polymers (Basel), 2021 Apr 27;13(9).
    PMID: 33925266 DOI: 10.3390/polym13091407
    In this review, the potential of natural fiber and kenaf fiber (KF) reinforced PLA composite filament for fused deposition modeling (FDM) 3D-printing technology is highlighted. Additive manufacturing is a material-processing method in which the addition of materials layer by layer creates a three-dimensional object. Unfortunately, it still cannot compete with conventional manufacturing processes, and instead serves as an economically effective tool for small-batch or high-variety product production. Being preformed of composite filaments makes it easiest to print using an FDM 3D printer without or with minimum alteration to the hardware parts. On the other hand, natural fiber-reinforced polymer composite filaments have gained great attention in the market. However, uneven printing, clogging, and the inhomogeneous distribution of the fiber-matrix remain the main challenges. At the same time, kenaf fibers are one of the most popular reinforcements in polymer composites. Although they have a good record on strength reinforcement, with low cost and light weight, kenaf fiber reinforcement PLA filament is still seldom seen in previous studies. Therefore, this review serves to promote kenaf fiber in PLA composite filaments for FDM 3D printing. To promote the use of natural fiber-reinforced polymer composite in AM, eight challenges must be solved and carried out. Moreover, some concerns arise to achieve long-term sustainability and market acceptability of KF/PLA composite filaments.
  17. Koo BK, Lee JM, Hwang D, Park S, Shiono Y, Yonetsu T, et al.
    JACC Asia, 2023 Oct;3(5):689-706.
    PMID: 38095005 DOI: 10.1016/j.jacasi.2023.07.003
    Coronary physiologic assessment is performed to measure coronary pressure, flow, and resistance or their surrogates to enable the selection of appropriate management strategy and its optimization for patients with coronary artery disease. The value of physiologic assessment is supported by a large body of evidence that has led to major recommendations in clinical practice guidelines. This expert consensus document aims to convey practical and balanced recommendations and future perspectives for coronary physiologic assessment for physicians and patients in the Asia-Pacific region based on updated information in the field that including both wire- and image-based physiologic assessment. This is Part 1 of the whole consensus document, which describes the general concept of coronary physiology, as well as practical information on the clinical application of physiologic indices and novel image-based physiologic assessment.
  18. Koh KB, Lam HS, Lee SH
    Br J Urol, 1993 May;71(5):609-11.
    PMID: 8518872
    Four cases of emphysematous pyelonephritis are reported and the pathogenesis, surgical implications and preferred mode of management are discussed. We have not found percutaneous drainage to be useful, but feel there is an important place for surgical drainage alone because of the potential for renal recovery and the risks of emergency nephrectomy.
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