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Chan WK, Sun JH, Liou MJ, Hsu CJ, Lu YL, Chou WY, Li YR, Liu FH. Novel and Advanced Ultrasound Techniques for Thyroid Thermal Ablation. Endocrinol Metab (Seoul) 2024; 39:40-46. [PMID: 38347707 PMCID: PMC10901668 DOI: 10.3803/enm.2024.1917] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/29/2023] [Accepted: 01/15/2024] [Indexed: 03/01/2024] Open
Abstract
Thyroid radiofrequency ablation and microwave ablation are widely adopted minimally invasive treatments for diverse thyroid conditions worldwide. Fundamental skills such as the trans-isthmic approach and the moving shot technique are crucial for performing thyroid ablation, and advanced techniques, including hydrodissection and vascular ablation, improve safety and efficacy and reduce complications. Given the learning curve associated with ultrasound-guided therapeutic procedures, operators need training and experience. While training models exist, limited attention has been given to ultrasound maneuvers in ablation needle manipulation. This article introduces two essential maneuvers, the zigzag moving technique and the alienate maneuver, while also reviewing the latest ultrasound techniques in thyroid ablation, contributing valuable insights into this evolving field.
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Affiliation(s)
- Wai-Kin Chan
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Chang Gung Memorial Hospital, Taoyuan, Taiwan
| | - Jui-Hung Sun
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Chang Gung Memorial Hospital, Taoyuan, Taiwan
| | - Miaw-Jene Liou
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Chang Gung Memorial Hospital, Taoyuan, Taiwan
- Chang Gung University, College of Medicine, Taoyuan, Taiwan
| | - Chia-Jung Hsu
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Chang Gung Memorial Hospital, Taoyuan, Taiwan
| | - Yu-Ling Lu
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Chang Gung Memorial Hospital, Taoyuan, Taiwan
| | - Wei-Yu Chou
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Chang Gung Memorial Hospital, Taoyuan, Taiwan
| | - Yan-Rong Li
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Chang Gung Memorial Hospital, Taoyuan, Taiwan
- Chang Gung University, College of Medicine, Taoyuan, Taiwan
| | - Feng-Hsuan Liu
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Chang Gung Memorial Hospital, Taoyuan, Taiwan
- Chang Gung University, College of Medicine, Taoyuan, Taiwan
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Cheng L, Chan WK, Peng Y, Qin H. Towards data-driven tele-medicine intelligence: community-based mental healthcare paradigm shift for smart aging amid COVID-19 pandemic. Health Inf Sci Syst 2023; 11:14. [PMID: 36923686 PMCID: PMC10011761 DOI: 10.1007/s13755-022-00198-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Accepted: 10/06/2022] [Indexed: 03/18/2023] Open
Abstract
Purpose Telemedicine are experiencing an unprecedented boom globally since the beginning of the COVID-19 pandemic. As the most vulnerable groups amid COVID-19, the digital delivery of healthcare poses great challenges to the elderly population, caregiver, health service providers, and health policy makers. To bridge the service delivery gaps between the telemedicine demand side and supply side, explore evidence-based approach for integrated care, address challenges for aging policy, and build foundation for the development of data-driven and community-based telemedicine, our R&D team applied translational research to design and develop telemedicine "SMART" for enhancing elderly mental health wellbeing amid COVID-19. Our aim is to investigate the preparedness mechanisms of mental health disease including response, intervention, and connection these three healthcare delivery pipelines with the collection, consolidation, and synergy of heath parameters and social determinants, using data analytics approach to achieve Evidence-Based Medicine (EBM). Methods A mix of quantitative and qualitative research design for scientifically rigorous consultation and analysis was conducted from Jan 2020 to June 2021 in Hong Kong. An exploratory and descriptive qualitative design was used in this study. The data were collected through focus group discussions conducted from elderly and their caregivers living in 10 main districts of Hong Kong. Our research pilot tested "SMART" targeting for elderly with mental health improvement needs. Baseline questionnaire with 110 tele-medicine product users includes questions on demographic information, self-rated mental health digital adoption. The follow-up five focus group discussions with 57 users (elderly and their caregivers) further explore the social determinants of telemedicine transformation and help propose the integrated telemedicine paradigm shift framework establishment, development, and enhancement. Results Grounded on the baseline needs assessment and feedbacks collected, it is evident that multi-dimensional health information from the four various streams (community, clinic, home, remote) and customized digital health solutions are playing a key role in addressing elderly mental health digital service needs and bridging digital divide. The designed tele-medicine product lines up health service provider (supplier side) and elderly specific needs (demand side) with our three-level design, enables elderly and their families to follow and control their own health management and connect with the service provider, community of practice (CoP), and health policy makers. Conclusion It's beneficial to involve elderly and gerontechnology stakeholders as part of Community-Based Participatory Research (CBPR) before and throughout the developing and delivery phases an integrated and age-friendly digital intervention. The challenges in applying and disseminating telemedicine reflected by the elderly and caregivers can be used as important input for further development and indicators for the sustainable and integrated elderly primary care framework. Supplementary Information The online version contains supplementary material available at 10.1007/s13755-022-00198-4.
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Affiliation(s)
- Lan Cheng
- Big Data Bio-Intelligence Lab, Big Data Institute, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong
| | - WK Chan
- Department of Computer Science and Engineering, Chinese University of Hong Kong, Sha Tin, Hong Kong
| | - Yi Peng
- School of Government, Nanjing University, Nanjing, China
| | - Harry Qin
- Faculty of Health and Social Sciences, The Hong Kong Polytechnic University, Kowloon, Hong Kong
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Van Trimpont M, Schalk AM, De Visser Y, Nguyen HA, Reunes L, Vandemeulebroecke K, Peeters E, Su Y, Lee H, Lorenzi PL, Chan WK, Mondelaers V, De Moerloose B, Lammens T, Goossens S, Van Vlierberghe P, Lavie A. In vivo stabilization of a less toxic asparaginase variant leads to a durable antitumor response in acute leukemia. Haematologica 2022; 108:409-419. [PMID: 35979719 PMCID: PMC9890011 DOI: 10.3324/haematol.2022.281390] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2002] [Indexed: 02/03/2023] Open
Abstract
Asparagine is a non-essential amino acid since it can either be taken up via the diet or synthesized by asparagine synthetase. Acute lymphoblastic leukemia (ALL) cells do not express asparagine synthetase or express it only minimally, which makes them completely dependent on extracellular asparagine for their growth and survival. This dependency makes ALL cells vulnerable to treatment with L-asparaginase, an enzyme that hydrolyzes asparagine. To date, all clinically approved L-asparaginases have significant L-glutaminase co-activity, associated with non-immune related toxic side effects observed during therapy. Therefore, reduction of L-glutaminase co-activity with concomitant maintenance of its anticancer L-asparaginase effect may effectively improve the tolerability of this unique drug. Previously, we designed a new alternative variant of Erwinia chrysanthemi (ErA; Erwinaze) with decreased L-glutaminase co-activity, while maintaining its L-asparaginase activity, by the introduction of three key mutations around the active site (ErA-TM). However, Erwinaze and our ErA-TM variant have very short half-lives in vivo. Here, we show that the fusion of ErA-TM with an albumin binding domain (ABD)-tag significantly increases its in vivo persistence. In addition, we evaluated the in vivo therapeutic efficacy of ABD-ErA-TM in a B-ALL xenograft model of SUP-B15. Our results show a comparable long-lasting durable antileukemic effect between the standard-of-care pegylated-asparaginase and ABD-ErA-TM L-asparaginase, but with fewer co-glutaminase-related acute side effects. Since the toxic side effects of current L-asparaginases often result in treatment discontinuation in ALL patients, this novel ErA-TM variant with ultra-low L-glutaminase co-activity and long in vivo persistence may have great clinical potential.
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Affiliation(s)
- Maaike Van Trimpont
- Cancer Research Institute Ghent (CRIG), Ghent, Belgium,Department of Biomolecular Medicine, Ghent University, Ghent, Belgium,Department of Diagnostic Sciences, Ghent University, Ghent, Belgium
| | - Amanda M. Schalk
- Department of Biochemistry and Molecular Genetics, University of Illinois at Chicago, Chicago, IL, USA
| | - Yanti De Visser
- Cancer Research Institute Ghent (CRIG), Ghent, Belgium,Department of Biomolecular Medicine, Ghent University, Ghent, Belgium,Department of Imaging and Pathology, KU Leuven, Leuven, Belgium
| | - Hien Anh Nguyen
- Department of Biochemistry and Molecular Genetics, University of Illinois at Chicago, Chicago, IL, USA
| | - Lindy Reunes
- Cancer Research Institute Ghent (CRIG), Ghent, Belgium,Department of Biomolecular Medicine, Ghent University, Ghent, Belgium
| | - Katrien Vandemeulebroecke
- Cancer Research Institute Ghent (CRIG), Ghent, Belgium,Department of Pediatric Hemato-Oncology and Stem Cell Transplantation, Ghent University Hospital, Ghent, Belgium,Department of Internal Medicine and Pediatrics, Ghent University, Ghent, Belgium
| | - Evelien Peeters
- Cancer Research Institute Ghent (CRIG), Ghent, Belgium,Department of Diagnostic Sciences, Ghent University, Ghent, Belgium
| | - Ying Su
- Department of Biochemistry and Molecular Genetics, University of Illinois at Chicago, Chicago, IL, USA
| | - Hyun Lee
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Illinois at Chicago (UIC), Chicago, IL, USA,Biophysics Core at Research Resources Center, University of Illinois at Chicago (UIC), Chicago, IL, USA
| | - Philip L. Lorenzi
- Metabolomics Core Facility, Department of Bioinformatics and Computational Biology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Wai-Kin Chan
- Metabolomics Core Facility, Department of Bioinformatics and Computational Biology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Veerle Mondelaers
- Cancer Research Institute Ghent (CRIG), Ghent, Belgium,Department of Pediatric Hemato-Oncology and Stem Cell Transplantation, Ghent University Hospital, Ghent, Belgium
| | - Barbara De Moerloose
- Cancer Research Institute Ghent (CRIG), Ghent, Belgium,Department of Pediatric Hemato-Oncology and Stem Cell Transplantation, Ghent University Hospital, Ghent, Belgium,Department of Internal Medicine and Pediatrics, Ghent University, Ghent, Belgium
| | - Tim Lammens
- Cancer Research Institute Ghent (CRIG), Ghent, Belgium,Department of Pediatric Hemato-Oncology and Stem Cell Transplantation, Ghent University Hospital, Ghent, Belgium,Department of Internal Medicine and Pediatrics, Ghent University, Ghent, Belgium
| | - Steven Goossens
- Cancer Research Institute Ghent (CRIG), Ghent, Belgium,Department of Diagnostic Sciences, Ghent University, Ghent, Belgium
| | - Pieter Van Vlierberghe
- Cancer Research Institute Ghent (CRIG), Ghent, Belgium,Department of Biomolecular Medicine, Ghent University, Ghent, Belgium,#PVV and AL contributed equally as co-senior authors
| | - Arnon Lavie
- Department of Biochemistry and Molecular Genetics, University of Illinois at Chicago, Chicago, USA; The Jesse Brown VA Medical Center, Chicago, IL.
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Grima-Reyes M, Vandenberghe A, Nemazanyy I, Meola P, Paul R, Reverso-Meinietti J, Martinez-Turtos A, Nottet N, Chan WK, Lorenzi PL, Marchetti S, Ricci JE, Chiche J. Tumoral microenvironment prevents de novo asparagine biosynthesis in B cell lymphoma, regardless of ASNS expression. Sci Adv 2022; 8:eabn6491. [PMID: 35857457 PMCID: PMC9258813 DOI: 10.1126/sciadv.abn6491] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Accepted: 05/17/2022] [Indexed: 06/15/2023]
Abstract
Depletion of circulating asparagine with l-asparaginase (ASNase) is a mainstay of leukemia treatment and is under investigation in many cancers. Expression levels of asparagine synthetase (ASNS), which catalyzes asparagine synthesis, were considered predictive of cancer cell sensitivity to ASNase treatment, a notion recently challenged. Using [U-13C5]-l-glutamine in vitro and in vivo in a mouse model of B cell lymphomas (BCLs), we demonstrated that supraphysiological or physiological concentrations of asparagine prevent de novo asparagine biosynthesis, regardless of ASNS expression levels. Overexpressing ASNS in ASNase-sensitive BCL was insufficient to confer resistance to ASNase treatment in vivo. Moreover, we showed that ASNase's glutaminase activity enables its maximal anticancer effect. Together, our results indicate that baseline ASNS expression (low or high) cannot dictate BCL dependence on de novo asparagine biosynthesis and predict BCL sensitivity to dual ASNase activity. Thus, except for ASNS-deficient cancer cells, ASNase's glutaminase activity should be considered in the clinic.
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Affiliation(s)
- Manuel Grima-Reyes
- Université Côte d’Azur, Inserm, C3M, Nice, France
- Equipe labellisée Ligue Contre le Cancer, Nice, France
| | - Ashaina Vandenberghe
- Université Côte d’Azur, Inserm, C3M, Nice, France
- Equipe labellisée Ligue Contre le Cancer, Nice, France
| | - Ivan Nemazanyy
- Plateforme d’étude du métabolisme SFR-Necker, Inserm US 24–CNRS UAR, 3633 Paris, France
| | - Pauline Meola
- Université Côte d’Azur, Inserm, C3M, Nice, France
- Equipe labellisée Ligue Contre le Cancer, Nice, France
| | - Rachel Paul
- Université Côte d’Azur, Inserm, C3M, Nice, France
- Equipe labellisée Ligue Contre le Cancer, Nice, France
| | - Julie Reverso-Meinietti
- Université Côte d’Azur, Inserm, C3M, Nice, France
- Equipe labellisée Ligue Contre le Cancer, Nice, France
| | - Adriana Martinez-Turtos
- Université Côte d’Azur, Inserm, C3M, Nice, France
- Equipe labellisée Ligue Contre le Cancer, Nice, France
| | | | - Wai-Kin Chan
- Department of Bioinformatics and Computational Biology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Philip L. Lorenzi
- Department of Bioinformatics and Computational Biology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Sandrine Marchetti
- Université Côte d’Azur, Inserm, C3M, Nice, France
- Equipe labellisée Ligue Contre le Cancer, Nice, France
| | - Jean-Ehrland Ricci
- Université Côte d’Azur, Inserm, C3M, Nice, France
- Equipe labellisée Ligue Contre le Cancer, Nice, France
| | - Johanna Chiche
- Université Côte d’Azur, Inserm, C3M, Nice, France
- Equipe labellisée Ligue Contre le Cancer, Nice, France
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Fung CK, Chow C, Chan WK, Choi EWK, To KF, Chan JKC, Cheuk W. Spindle cell/sclerosing rhabdomyosarcoma with DCTN1::ALK fusion: broadening the molecular spectrum with potential therapeutic implications. Virchows Arch 2022; 480:927-932. [PMID: 35229187 DOI: 10.1007/s00428-022-03305-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Revised: 02/17/2022] [Accepted: 02/20/2022] [Indexed: 12/20/2022]
Abstract
Spindle cell/sclerosing rbabdomyosarcoma (RMS) is a recently characterized variant of RMS with several distinct molecular subtypes. We describe an example occurring in the tongue of a 10-year-old boy with a novel DCTN1::ALK fusion. The tumor exhibited infiltrative growth and was comprised of fascicles and focally whorls of spindle cells with eosinophilic cytoplasm, in a collagenous or myxoid stroma. Moderate cytologic atypia, mitotic activity (2/10 HPFs), and perineural invasion were identified. The tumor cells expressed actin, desmin, MyoD1, myogenin, and ALK. An in-frame fusion between DCTN1 exon 26 and ALK exon 20 was detected by RNA sequencing, which was confirmed by split reads and supported by FISH studies. The tumor showed an indolent behavior with local recurrence 3 years after excision. This study broadens the molecular spectrum of spindle cell/sclerosing RMS and this molecular aberration may represent a potential therapeutic target for unresectable or disseminated disease.
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Affiliation(s)
- C K Fung
- Department of Pathology, United Christian Hospital, Kwun Tong, Hong Kong
| | - Chit Chow
- Department of Cellular and Anatomical Pathology, Chinese University of Hong Kong, Shatin, Hong Kong
| | - W K Chan
- Department of Pathology, Hong Kong Sanatorium and Hospital, Happy Valley, Hong Kong
| | - Eric W K Choi
- Department of Pathology, Hong Kong Sanatorium and Hospital, Happy Valley, Hong Kong
| | - K F To
- Department of Cellular and Anatomical Pathology, Chinese University of Hong Kong, Shatin, Hong Kong
| | - John K C Chan
- Department of Pathology, Queen Elizabeth Hospital, Hong Kong, SAR, China
| | - Wah Cheuk
- Department of Pathology, Queen Elizabeth Hospital, Hong Kong, SAR, China.
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Li YR, Chou WY, Chan WK, Cheng KL, Sun JH, Liu FH, Chen ST, Liou MJ. Successful Applications of Food-Assisted and -Simulated Training Model of Thyroid Radiofrequency Ablation. Front Endocrinol (Lausanne) 2022; 13:809835. [PMID: 35432189 PMCID: PMC9009177 DOI: 10.3389/fendo.2022.809835] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Accepted: 03/07/2022] [Indexed: 11/16/2022] Open
Abstract
BACKGROUND Radiofrequency ablation (RFA) for benign thyroid nodules is one kind of scarless treatment for symptomatic or cosmetic benign thyroid nodules. However, how to train RFA-naive physicians to become qualified operators for thyroid RFA is an important issue. Our study aimed to introduce a successful training model of thyroid RFA. MATERIALS AND METHODS We used a food-assisted and -simulated training model of thyroid RFA. Chicken hearts were simulated into thyroid nodules, three-layer pork meats were simulated into peri-thyroid structure, and gel bottles were simulated into trachea, respectively. Successful training ablations were defined as chicken hearts that were fully cooked. After repeating training ablations of chicken hearts at least 100 times with the nearly 100% success rates for three young trainees, they served as the first assistant for the real procedures of thyroid RFA and then were qualified to perform thyroid RFA on real patients under the supervision of one experienced interventional radiologist. RESULTS 23 real patients who received RFA and follow-up at least 6 months after treatment were included in Linkou Chang Gung Memorial Hospital from January 1, 2020 to October 1, 2021. Three young endocrinologists performed thyroid RFA independently. The outcomes were volume reduction rate (VRR), major complications and minor complications. The median VRR at 12 months was 82.00%, two major complications were transient hoarseness, and three minor complications were wound pain. All complications were completely recovered within three days. CONCLUSIONS For young and RFA-native physicians without any basic skills of echo-guided intervention, this food-assisted and -simulated training model of thyroid RFA was useful for medical training and education.
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Affiliation(s)
- Yan-Rong Li
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Linkou Chang Gung Memorial Hospital, Taoyuan, Taiwan
- College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Wei-Yu Chou
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Linkou Chang Gung Memorial Hospital, Taoyuan, Taiwan
| | - Wai-Kin Chan
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Linkou Chang Gung Memorial Hospital, Taoyuan, Taiwan
| | - Kai-Lun Cheng
- Department of Medical Imaging, Chung Shan Medical University Hospital, Taichung, Taiwan
- School of Medical Imaging and Radiological Sciences, Chung Shan Medical University, Taichung, Taiwan
| | - Jui-Hung Sun
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Linkou Chang Gung Memorial Hospital, Taoyuan, Taiwan
| | - Feng-Hsuan Liu
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Linkou Chang Gung Memorial Hospital, Taoyuan, Taiwan
- College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Szu-Tah Chen
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Linkou Chang Gung Memorial Hospital, Taoyuan, Taiwan
- College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Miaw-Jene Liou
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Linkou Chang Gung Memorial Hospital, Taoyuan, Taiwan
- College of Medicine, Chang Gung University, Taoyuan, Taiwan
- *Correspondence: Miaw-Jene Liou,
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7
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Karuthan SR, Koh PS, Chinna K, Chan WK. Barcelona Clinic Liver Cancer and Hong Kong Liver Cancer staging systems for prediction of survival among Hepatocellular Carcinoma patients. Med J Malaysia 2021; 76:199-204. [PMID: 33742628] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
INTRODUCTION We aimed to compare the Barcelona Clinic Liver Cancer (BCLC) and Hong Kong Liver Cancer (HKLC) staging systems. MATERIALS AND METHODS This is a retrospective study on patients with newly diagnosed hepatocellular carcinoma (HCC) at the University Malaya Medical Centre between 2011 and 2014. Survival times were analysed using the Kaplan- Meier procedure and comparison between groups was done using the log rank test. RESULTS The data of 190 patients was analysed. Chronic hepatitis B was the most common aetiology for HCC (43.7%), but a large proportion was cryptogenic or non-alcoholic steatohepatitis-related (41.6%). Only 11.1% were diagnosed early (BCLC Stage 0-A) while majority were diagnosed at an intermediate stage (BCLC Stage B, 53.7%). The median survival rate was significantly different between the different groups when either of the staging systems was used (p<0.05 for all comparisons). However, the two staging systems lacked agreement (weighted kappa 0.519, 95%CI: 0.449, 0.589) with significant difference in median survival rates between BCLC Stage A and HKLC Stage 2, and between BCLC Stage C and HKLC Stage 4. CONCLUSION Both staging systems were able to stratify patients according to survival, but they only had moderate agreement with significant differences observed in two groups of the staging systems.
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Affiliation(s)
- S R Karuthan
- University Malaya, Faculty of Medicine, Department of Medicine, Kuala Lumpur, Malaysia
| | - P S Koh
- University Malaya, Faculty of Surgery, Department of Medicine, Kuala Lumpur, Malaysia
| | - K Chinna
- Taylor's University, Faculty of Health and Medical Sciences, School of Medicine, Kuala Lumpur, Malaysia
| | - W K Chan
- University Malaya, Faculty of Medicine, Department of Medicine, Department of Medicine, Kuala Lumpur, Malaysia.
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Yuan Y, Lo KC, Szeto L, Chan WK. Synthesis of Pyrazinopyrazine-Fused Azaacenes through Direct Condensation Reactions between Quinoxalinediamine and Diketones. J Org Chem 2020; 85:6372-6379. [PMID: 32312048 DOI: 10.1021/acs.joc.9b03504] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We report the synthesis of a new type of pyrazinopyrazine-fused azaacene molecules by a simple and versatile procedure. 6,9-Dihexyldithieno[3,2-f:2',3'-h]quinoxaline-2,3-diamine was synthesized through the condensation between 2,7-dihexylbenzo[1,2-b:6,5-b']dithiophene-4,5-diamine and bis(2,2,2-trifluoroethyl) oximidate. A series of derivatized molecules with extended two-dimensional aromatic fused-ring structures could be obtained by simple condensation reactions between the quinoxalinediamine intermediate and various diketones. The reaction was proved to be effective for the construction of tetrazaacene derivatives with extended heterocyclic aromatic ring systems. The molecules obtained exhibit low-lying LUMO levels that can be fine-tuned by modifying the molecular structure. Crystallographic results showed that in a solid state, the molecules form "brick wall" structures with a close π-π stacking mode. The stacking between the π-ring systems in the molecules could be further enhanced by expanding the large 2D planar-conjugated structure.
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Affiliation(s)
- Yuping Yuan
- Department of Chemistry, the University of Hong Kong, Pokfulam Road, Hong Kong SAR 999077, China
| | - Kin-Cheung Lo
- Department of Chemistry, the University of Hong Kong, Pokfulam Road, Hong Kong SAR 999077, China
| | - Lap Szeto
- Department of Chemistry, the University of Hong Kong, Pokfulam Road, Hong Kong SAR 999077, China
| | - Wai-Kin Chan
- Department of Chemistry, the University of Hong Kong, Pokfulam Road, Hong Kong SAR 999077, China
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Lubkowski J, Vanegas J, Chan WK, Lorenzi PL, Weinstein JN, Sukharev S, Fushman D, Rempe S, Anishkin A, Wlodawer A. Mechanism of Catalysis by l-Asparaginase. Biochemistry 2020; 59:1927-1945. [PMID: 32364696 DOI: 10.1021/acs.biochem.0c00116] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Two bacterial type II l-asparaginases, from Escherichia coli and Dickeya chrysanthemi, have played a critical role for more than 40 years as therapeutic agents against juvenile leukemias and lymphomas. Despite a long history of successful pharmacological applications and the apparent simplicity of the catalytic reaction, controversies still exist regarding major steps of the mechanism. In this report, we provide a detailed description of the reaction catalyzed by E. coli type II l-asparaginase (EcAII). Our model was developed on the basis of new structural and biochemical experiments combined with previously published data. The proposed mechanism is supported by quantum chemistry calculations based on density functional theory. We provide strong evidence that EcAII catalyzes the reaction according to the double-displacement (ping-pong) mechanism, with formation of a covalent intermediate. Several steps of catalysis by EcAII are unique when compared to reactions catalyzed by other known hydrolytic enzymes. Here, the reaction is initiated by a weak nucleophile, threonine, without direct assistance of a general base, although a distant general base is identified. Furthermore, tetrahedral intermediates formed during the catalytic process are stabilized by a never previously described motif. Although the scheme of the catalytic mechanism was developed only on the basis of data obtained from EcAII and its variants, this novel mechanism of enzymatic hydrolysis could potentially apply to most (and possibly all) l-asparaginases.
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Affiliation(s)
- Jacek Lubkowski
- Macromolecular Crystallography Laboratory, Center for Cancer Research, National Cancer Institute, Frederick, Maryland 21702, United States
| | - Juan Vanegas
- Department of Physics, The University of Vermont, Burlington, Vermont 05408, United States
| | - Wai-Kin Chan
- Department of Bioinformatics and Computational Biology, The University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030, United States
| | - Philip L Lorenzi
- Department of Bioinformatics and Computational Biology, The University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030, United States
| | - John N Weinstein
- Department of Bioinformatics and Computational Biology, The University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030, United States
| | - Sergei Sukharev
- Department of Biology, University of Maryland, College Park, Maryland 20742, United States
| | - David Fushman
- Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742, United States
| | - Susan Rempe
- Center for Biological and Engineering Sciences, Sandia National Laboratories, Albuquerque, New Mexico 87185, United States
| | - Andriy Anishkin
- Department of Biology, University of Maryland, College Park, Maryland 20742, United States
| | - Alexander Wlodawer
- Macromolecular Crystallography Laboratory, Center for Cancer Research, National Cancer Institute, Frederick, Maryland 21702, United States
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Lo C, Chan WK, Lo G. Atypical Langerhans Cell Histiocytosis: A Case Report. Hong Kong Journal of Radiology 2020. [DOI: 10.12809/hkjr2016914] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Affiliation(s)
- C Lo
- Department of Radiology, Queen Mary Hospital, Pokfulam, Hong Kong
| | - WK Chan
- Department of Pathology, Hong Kong Sanatorium & Hospital, Happy Valley, Hong Kong
| | - G Lo
- Department of Radiology, Hong Kong Sanatorium & Hospital, Happy Valley, Hong Kong
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11
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Kuan PX, Chan WK, Chua PF, Yeo J, Sapri FE, Bujang MA, Said A. Lifestyle factors associated with cardiovascular risk among healthcare workers from the tertiary hospitals in Sarawak. Malays Fam Physician 2020; 15:15-22. [PMID: 32284800 PMCID: PMC7136671] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
INTRODUCTION A cross-sectional study is used to evaluate the lifestyle factors associated with cardiovascular disease (CVD) risk among healthcare workers in tertiary hospitals in Sarawak, Malaysia. METHODS A questionnaire-based survey using the Simple Lifestyle Indicator Questionnaire (SLIQ) was administered to, and anthropometric measurements were collected from, 494 healthcare workers. RESULTS The mean age of the subjects was 32.4±8.4, with a range of 19 to 59 years. The subjects were from the allied health (45.5%), management and professional (25.1%) and executive (29.4%) fields. Overall, 47.4% of the subjects were of normal weight, 30.2% were overweight, 17.2% were obese and 5.2% were underweight. The mean number of working hours per week for the subjects was 47.6±14.0 with the highest working hours found among the management and professional group, followed by the executive and allied health groups. Overall, 39.7% of the healthcare workers worked office hours, 36.6% worked within the shift system, 20.9% worked office hours and were on-call and the remaining 2.8% worked a mixture of office hours and shifts. Based on the SLIQ score, 58.1% were classified as at intermediate risk for CVD, 38.5% were in the healthy category and 3.4% were in the unhealthy category. Factors associated with a healthier lifestyle were being female (Odds Ratio [OR]= 12.1; CI=3.2-46.4), professional (mean score= 6.70), in the allied health group (mean score=7.33) and in the normal BMI group (OR= 9.3, CI= 1.8-47.0). CONCLUSION In our study, healthcare workers had an intermediate risk of developing CVD in the future. Thus, there is a need to intervene in the lifestyle factors contributing to CVD.
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Affiliation(s)
- P X Kuan
- Clinical Research Centre (CRC) Sungai Buloh Hospital, Jalan Hospital 47000 Selangor, Malaysia
| | - W K Chan
- Department of Anaesthesiology and Intensive Care, Sarawak General Hospital, Jalan Hospital, 93586 Kuching, Sarawak, Malaysia
| | - P F Chua
- Department of Paraclinical Science Faculty of Medicine and Health Sciences, Universiti Malaysia Sarawak, Malaysia
| | - Jjp Yeo
- Department of Cardiology, Sarawak General Hospital Heart Centre, Jalan Lingkaran Luar Kuching, 94300 Kota Samarahan, Sarawak, Malaysia
| | - F E Sapri
- Clinical Research Centre, Sarawak General Hospital, Jalan Hospital 93586 Kuching, Sarawak, Malaysia
| | - M A Bujang
- Clinical Research Centre, Sarawak General Hospital, Jalan Hospital, 93586 Kuching, Sarawak, Malaysia
| | - A Said
- Faculty of Medicine and Health Sciences, Universiti Malaysia Sarawak, 94300 Kota Samarahan Sarawak, Malaysia
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Chan WK, Horvath TD, Tan L, Link T, Harutyunyan KG, Pontikos MA, Anishkin A, Du D, Martin LA, Yin E, Rempe SB, Sukharev S, Konopleva M, Weinstein JN, Lorenzi PL. Glutaminase Activity of L-Asparaginase Contributes to Durable Preclinical Activity against Acute Lymphoblastic Leukemia. Mol Cancer Ther 2019; 18:1587-1592. [PMID: 31209181 DOI: 10.1158/1535-7163.mct-18-1329] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2018] [Revised: 03/25/2019] [Accepted: 06/11/2019] [Indexed: 11/16/2022]
Abstract
We and others have reported that the anticancer activity of L-asparaginase (ASNase) against asparagine synthetase (ASNS)-positive cell types requires ASNase glutaminase activity, whereas anticancer activity against ASNS-negative cell types does not. Here, we attempted to disentangle the relationship between asparagine metabolism, glutamine metabolism, and downstream pathways that modulate cell viability by testing the hypothesis that ASNase anticancer activity is based on asparagine depletion rather than glutamine depletion per se. We tested ASNase wild-type (ASNaseWT) and its glutaminase-deficient Q59L mutant (ASNaseQ59L) and found that ASNase glutaminase activity contributed to durable anticancer activity against xenografts of the ASNS-negative Sup-B15 leukemia cell line in NOD/SCID gamma mice, whereas asparaginase activity alone yielded a mere growth delay. Our findings suggest that ASNase glutaminase activity is necessary for durable, single-agent anticancer activity in vivo, even against ASNS-negative cancer types.
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Affiliation(s)
- Wai-Kin Chan
- Department of Bioinformatics and Computational Biology, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Thomas D Horvath
- Department of Bioinformatics and Computational Biology, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Lin Tan
- Department of Bioinformatics and Computational Biology, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Todd Link
- Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Karine G Harutyunyan
- Department of Leukemia, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Michael A Pontikos
- Department of Bioinformatics and Computational Biology, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Andriy Anishkin
- Department of Biology, University of Maryland, College Park, Maryland
| | - Di Du
- Department of Bioinformatics and Computational Biology, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Leona A Martin
- Department of Bioinformatics and Computational Biology, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Eric Yin
- Department of Bioinformatics and Computational Biology, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Susan B Rempe
- Center for Biological and Engineering Sciences, Sandia National Laboratories, Albuquerque, New Mexico
| | - Sergei Sukharev
- Department of Biology, University of Maryland, College Park, Maryland
| | - Marina Konopleva
- Department of Leukemia, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - John N Weinstein
- Department of Bioinformatics and Computational Biology, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Philip L Lorenzi
- Department of Bioinformatics and Computational Biology, The University of Texas MD Anderson Cancer Center, Houston, Texas.
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Chan CK, Wong KH, Lee MP, Chan KC, Leung CC, Leung EC, Chan WK, Mak IK. Risk factors associated with 1-year mortality among patients with HIV-associated tuberculosis in areas with intermediate tuberculosis burden and low HIV prevalence. Hong Kong Med J 2019; 24:473-483. [PMID: 30262675 DOI: 10.12809/hkmj187303] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
INTRODUCTION Data are limited regarding risk factors for mortality among patients with human immunodeficiency virus (HIV)-associated tuberculosis (TB) in areas with low HIV prevalence and intermediate TB burden, such as the Western Pacific region. This study aimed to assess such risk factors in Hong Kong, which has an intermediate TB burden and low HIV prevalence. METHODS We conducted a retrospective cohort analysis of adult patients reported to the Hong Kong TB-HIV Registry between 2006 and 2015. Baseline characteristics were compared with Kaplan-Meier estimates. Cox proportional hazards regression modelling was used to identify factors associated with mortality. RESULTS Of 299 patients studied, 21 (7.0%) died within 12 months of anti-TB treatment (median [interquartile range], 7.5 [3.8-10] months). The median age of death was 54 (interquartile range, 40.5-75.0) years. The cause of death was TB in five and unrelated to TB in the remaining 16. Cox proportional hazards regression showed that older age (adjusted hazard ratio=4.5; 95% confidence interval [CI]=1.4-14.9), history of drug addiction (4.6; 95% CI=1.6-13.0), and low baseline CD4 cell count of <50/μL (2.9; 95% CI=1.1-7.7) were independent risk factors for death within 12 months. CONCLUSION This study complements previous studies by providing information regarding risk factors associated with mortality among patients with HIV-associated TB in areas with intermediate TB burden and low HIV prevalence. The results from our study may guide targeted measures to improve survival in other areas with intermediate TB burden and low HIV prevalence, such as the Western Pacific region.
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Affiliation(s)
- C K Chan
- Tuberculosis and Chest Service, Centre for Health Protection, Department of Health, Hong Kong
| | - K H Wong
- Head Office, Centre for Health Protection, Department of Health, Hong Kong
| | - M P Lee
- Department of Medicine, Queen Elizabeth Hospital, Hospital Authority, Hong Kong
| | - K Cw Chan
- Integrated Treatment Centre, Special Preventive Programme, Centre for Health Protection, Department of Health, Hong Kong
| | - C C Leung
- Tuberculosis and Chest Service, Centre for Health Protection, Department of Health, Hong Kong
| | - E Cc Leung
- Tuberculosis and Chest Service, Centre for Health Protection, Department of Health, Hong Kong
| | - W K Chan
- Integrated Treatment Centre, Special Preventive Programme, Centre for Health Protection, Department of Health, Hong Kong
| | - I Ky Mak
- Tuberculosis and Chest Service, Centre for Health Protection, Department of Health, Hong Kong
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Chan WK, Yeoh KY, Lim CY, Lai SM, Lee JL, Leow AHR, Goh KL. Hepatitis B virus infection among children of hepatitis B surface antigen positive mothers in a Malaysian hospital. Med J Malaysia 2018; 73:137-140. [PMID: 29962496] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
INTRODUCTION There have been no published data on the transmission of hepatitis B virus (HBV) infection among children of hepatitis B surface antigen (HBsAg) positive mothers in Malaysia. METHODS This is a cross-sectional study of all the children of HBsAg-positive mothers who delivered at the University of Malaya Medical Centre between 1993 and 2000. RESULTS A total of 60 HBsAg-positive mothers and their 154 children participated in the study. HBsAg was detected in four children (2.6%) while IgG antibody to the hepatitis B core antigen (anti-HBc IgG) was detected in seventeen children (11.0%). The mother's age at childbirth was significantly lower in the children with detectable HBsAg (22.5±6.1 years vs. 29.7±4.5 years, p=0.043) and anti-HBc IgG (26.6±6.1 years vs. 30.0±4.3 years, p=0.004). Children born in the 1980s were significantly more likely to have detectable HBsAg (18.8% vs. 0.7%, p=0.004) and anti-HBc IgG (37.5% vs. 8.0%, p=0.000) compared with those born later. All children with detectable HBsAg were born via spontaneous vaginal delivery, and hepatitis B immunoglobulin was either not given or the administration status was unknown. The majority of mothers with chronic HBV infection (70.4%) were not under any regular follow-up for their chronic HBV infection and the main reason was the lack of awareness of the need to do so (47.4%). CONCLUSION Transmission of HBV infection among children of HBsAg-positive mothers in Malaysia is low. However, attention needs to be given to the high rate of HBsAgpositive mothers who are not on any regular follow-up.
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Affiliation(s)
- W K Chan
- University of Malaya, Faculty of Medicine, Department of Medicine, Gastroenterology and Hepatology Unit, Kuala Lumpur, Malaysia.
| | - K Y Yeoh
- University of Malaya, Faculty of Medicine, Department of Medicine, Gastroenterology and Hepatology Unit, Kuala Lumpur, Malaysia
| | - C Y Lim
- University of Malaya, Faculty of Medicine, Department of Medicine, Gastroenterology and Hepatology Unit, Kuala Lumpur, Malaysia
| | - S M Lai
- University of Malaya, Faculty of Medicine, Department of Medicine, Gastroenterology and Hepatology Unit, Kuala Lumpur, Malaysia
| | - J L Lee
- University of Malaya, Faculty of Medicine, Department of Medicine, Gastroenterology and Hepatology Unit, Kuala Lumpur, Malaysia
| | - A H R Leow
- University of Malaya, Faculty of Medicine, Department of Medicine, Gastroenterology and Hepatology Unit, Kuala Lumpur, Malaysia
| | - K L Goh
- University of Malaya, Faculty of Medicine, Department of Medicine, Gastroenterology and Hepatology Unit, Kuala Lumpur, Malaysia
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15
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Kam CS, Leung TL, Liu F, Djurišić AB, Xie MH, Chan WK, Zhou Y, Shih K. Lead removal from water – dependence on the form of carbon and surface functionalization. RSC Adv 2018; 8:18355-18362. [PMID: 35541110 PMCID: PMC9080567 DOI: 10.1039/c8ra02264j] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Accepted: 05/13/2018] [Indexed: 12/11/2022] Open
Abstract
Functionalization with same functional group results in varied lead adsorption performance for different nanostructured carbon materials.
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Affiliation(s)
- Chun Sing Kam
- Department of Physics
- The University of Hong Kong
- Hong Kong
| | - Tik Lun Leung
- Department of Physics
- The University of Hong Kong
- Hong Kong
| | - Fangzhou Liu
- Department of Physics
- The University of Hong Kong
- Hong Kong
| | | | - Mao Hai Xie
- Department of Physics
- The University of Hong Kong
- Hong Kong
| | - Wai-Kin Chan
- Department of Chemistry
- The University of Hong Kong
- Hong Kong
| | - Ying Zhou
- Department of Civil Engineering
- The University of Hong Kong
- Hong Kong
| | - Kaimin Shih
- Department of Civil Engineering
- The University of Hong Kong
- Hong Kong
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Abstract
A healthy 28-year-old man presented with multiple brief episodes of convulsion. He was found to have ventricular fibrillation which required defibrillation in the emergency department. After exclusion of organic heart diseases, Brugada syndrome was diagnosed and required implantable cardioverter defibrillator (ICD) implantation. The case emphasized the recognition of malignant cardiac dysrrhythmias as a cause for seizures. The management in the emergency department was discussed.
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17
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Koh KC, Islam M, Chan WK, Lee WY, Ho YW, Alsagoff SAH, Yusof RA. Missed opportunities for earlier HIV-testing in patients with HIV infection referred to a tertiary hospital, a cross-sectional study. Med J Malaysia 2017; 72:209-214. [PMID: 28889131] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
INTRODUCTION In Malaysia, the prevalence of missed opportunities for HIV-testing is unknown. Missed opportunities have been linked to late diagnosis of HIV and poorer outcome for patients. We describe missed opportunities for earlier HIV-testing in newly-HIV-diagnosed patients. METHODS Cross sectional study. Adult patients diagnosed with HIV infection and had at least one medical encounter in a primary healthcare setting during three years prior to diagnosis were included. We collected data on sociodemographic characteristics, patient characteristics at diagnosis, HIV-related conditions and whether they were subjected to risk assessment and offered HIV testing during the three years prior to HIV diagnosis. RESULTS 65 newly HIV-diagnosed patients (male: 92.3%; Malays: 52.4%; single: 66.7%; heterosexual: 41%; homosexual 24.6%; CD4 <350 at diagnosis: 63%). 93.8% were unaware of their HIV status at diagnosis. Up to 56.9% had presented with HIV-related conditions at a primary healthcare facility during the three years prior to diagnosis. Slightly more than half were had risk assessment done and only 33.8% were offered HIV-testing. CONCLUSIONS Missed opportunities for HIV-testing was unacceptably high with insufficient risk assessment and offering of HIV-testing. Risk assessment must be promoted and primary care physicians must be trained to recognize HIV-related conditions that will prompt them to offer HIVtesting.
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Affiliation(s)
- K C Koh
- International Medical University, Department of Medicine, Seremban, Negeri Sembilan, Malaysia.
| | - M Islam
- International Medical University, Department of Medicine, Seremban, Negeri Sembilan, Malaysia
| | - W K Chan
- International Medical University, Department of Medicine, Seremban, Negeri Sembilan, Malaysia
| | - W Y Lee
- International Medical University, Department of Medicine, Seremban, Negeri Sembilan, Malaysia
| | - Y W Ho
- International Medical University, Department of Medicine, Seremban, Negeri Sembilan, Malaysia
| | - S A H Alsagoff
- International Medical University, Department of Medicine, Seremban, Negeri Sembilan, Malaysia
| | - R A Yusof
- Hospital Tuanku Ja'afar, Department of Medicine, Seremban, Negeri Sembilan, Malaysia
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Abstract
This paper presents a comparison of manufacturing techniques used in the development of an axial blood pump impeller. In this development process the impeller was designed and its performance was evaluated with the aid of computational fluid dynamics (CFD). Prototypes of those designs where the CFD results show promise were needed in sufficient quantities at a low cost for experimental validation of the CFD results. As the impeller is less than 16 mm in diameter with a maximum blade thickness of about 1.5 mm, innovative manufacturing techniques are explored in this paper to determine the best process for quick fabrication of prototypes that are dimensionally accurate, structurally robust and low in cost. Four rapid prototyping techniques were explored. The completed parts were compared on the basis of manufacturing time, quality and strength of parts obtained, manufacturing cost and also in vitro performances. Based on these studies, it was concluded that selective laser sintering (SLS) is the most appropriate method for the quick production of prototype parts for evaluation of pump performance.
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Affiliation(s)
- W K Chan
- School of Mechanical and Production Engineering, Thermal and Fluids Engineering Division, Nanyang Technological University, Singapore, Singapore
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19
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Shum EY, Jones SH, Shao A, Chousal JN, Krause MD, Chan WK, Lou CH, Espinoza JL, Song HW, Phan MH, Ramaiah M, Huang L, McCarrey JR, Peterson KJ, De Rooij DG, Cook-Andersen H, Wilkinson MF. The Antagonistic Gene Paralogs Upf3a and Upf3b Govern Nonsense-Mediated RNA Decay. Cell 2016; 165:382-95. [PMID: 27040500 PMCID: PMC4826573 DOI: 10.1016/j.cell.2016.02.046] [Citation(s) in RCA: 109] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Revised: 02/02/2016] [Accepted: 02/20/2016] [Indexed: 01/11/2023]
Abstract
Gene duplication is a major evolutionary force driving adaptation and speciation, as it allows for the acquisition of new functions and can augment or diversify existing functions. Here, we report a gene duplication event that yielded another outcome--the generation of antagonistic functions. One product of this duplication event--UPF3B--is critical for the nonsense-mediated RNA decay (NMD) pathway, while its autosomal counterpart--UPF3A--encodes an enigmatic protein previously shown to have trace NMD activity. Using loss-of-function approaches in vitro and in vivo, we discovered that UPF3A acts primarily as a potent NMD inhibitor that stabilizes hundreds of transcripts. Evidence suggests that UPF3A acquired repressor activity through simple impairment of a critical domain, a rapid mechanism that may have been widely used in evolution. Mice conditionally lacking UPF3A exhibit "hyper" NMD and display defects in embryogenesis and gametogenesis. Our results support a model in which UPF3A serves as a molecular rheostat that directs developmental events.
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Affiliation(s)
- Eleen Y. Shum
- Department of Reproductive Medicine, School of Medicine, University
of California, San Diego, La Jolla, California, USA
| | - Samantha H. Jones
- Department of Reproductive Medicine, School of Medicine, University
of California, San Diego, La Jolla, California, USA
| | - Ada Shao
- Department of Reproductive Medicine, School of Medicine, University
of California, San Diego, La Jolla, California, USA
| | - Jennifer N. Chousal
- Department of Reproductive Medicine, School of Medicine, University
of California, San Diego, La Jolla, California, USA
| | - Matthew D. Krause
- Department of Reproductive Medicine, School of Medicine, University
of California, San Diego, La Jolla, California, USA
| | - Wai-Kin Chan
- Department of Bioinformatics and Computational Biology, University
of Texas M.D. Anderson Cancer Center, Houston, Texas, USA
| | - Chih-Hong Lou
- Department of Reproductive Medicine, School of Medicine, University
of California, San Diego, La Jolla, California, USA
| | - Josh L. Espinoza
- Department of Reproductive Medicine, School of Medicine, University
of California, San Diego, La Jolla, California, USA
| | - Hye-Won Song
- Department of Reproductive Medicine, School of Medicine, University
of California, San Diego, La Jolla, California, USA
| | - Mimi H. Phan
- Department of Reproductive Medicine, School of Medicine, University
of California, San Diego, La Jolla, California, USA
| | - Madhuvanthi Ramaiah
- Department of Reproductive Medicine, School of Medicine, University
of California, San Diego, La Jolla, California, USA
| | - Lulu Huang
- Department of Reproductive Medicine, School of Medicine, University
of California, San Diego, La Jolla, California, USA
| | - John R. McCarrey
- Department of Biology, University of Texas at San Antonio, San
Antonio, Texas, USA
| | - Kevin J. Peterson
- Department of Biology, Dartmouth College, Hanover, New Hampshire,
USA
| | - Dirk G. De Rooij
- Reproductive Biology Group, Division of Developmental Biology,
Department of Biology, Faculty of Science, Utrecht University, Utrecht, The
Netherlands
| | - Heidi Cook-Andersen
- Department of Reproductive Medicine, School of Medicine, University
of California, San Diego, La Jolla, California, USA
| | - Miles F. Wilkinson
- Department of Reproductive Medicine, School of Medicine, University
of California, San Diego, La Jolla, California, USA,Institute of Genomic Medicine, University of California, San Diego,
La Jolla, California, USA
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Liong CC, Ravindran S, Gnana Kumar G, Chin EF, Koh PS, Chan WK. Enteropathy-associated T-cell lymphoma: An extremely rare cause of chronic diarrhoea. Med J Malaysia 2016; 71:88-90. [PMID: 27326953] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Chronic diarrhoea in tropical countries may be due to a myriad of causes from infective to non-infective. This case report illustrates the challenges faced in the investigation of a middle-age Chinese gentleman who presented with chronic diarrhoea and weight loss. The diagnosis of type II enteropathy-associated T-cell lymphoma (EATL) was finally made. The diagnosis of EATL was least suspected as the condition is almost unheard of in this part of the world. The epidemiology, presentation, diagnosis, management and prognosis of this rare condition are discussed.
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Affiliation(s)
- C C Liong
- University of Malaya, Faculty of Medicine, Department of Medicine, Gastroenterology and Hepatology Unit, Kuala Lumpur, Malaysia.
| | - S Ravindran
- University of Malaya, Faculty of Medicine, Department of Pathology, Kuala Lumpur, Malaysia
| | - G Gnana Kumar
- University of Malaya, Faculty of Medicine, Department of Biomedical Imaging, Kuala Lumpur, Malaysia
| | - E F Chin
- University of Malaya, Faculty of Medicine, Department of Medicine, Hematology Unit, Kuala Lumpur, Malaysia
| | - P S Koh
- University of Malaya, Faculty of Medicine, Department of Surgery, Kuala Lumpur, Malaysia
| | - W K Chan
- University of Malaya, Faculty of Medicine, Department of Medicine, Gastroenterology and Hepatology Unit, Kuala Lumpur, Malaysia
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Triplett BM, Shook DR, Eldridge P, Li Y, Kang G, Dallas M, Hartford C, Srinivasan A, Chan WK, Suwannasaen D, Inaba H, Merchant TE, Pui CH, Leung W. Erratum: Rapid memory T-cell reconstitution recapitulating CD45RA-depleted haploidentical transplant graft content in patients with hematologic malignancies. Bone Marrow Transplant 2015; 50:1012. [DOI: 10.1038/bmt.2015.139] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Abstract
OBJECTIVE To understand legislation combating counterfeit drugs in Hong Kong. DESIGN This study consisted of two parts. In part I, counterfeit drugs–related ordinances and court cases were reviewed. In part II, indepth interviews of the stakeholders were described. SETTING Hong Kong. PARTICIPANTS All Hong Kong ordinances were screened manually to identify those combating counterfeit drugs. Court cases were searched for each of the identified cases. Then, the relevant judgement justifications were analysed to identify sentencing issues. Indepth interviews with the stakeholders were conducted to understand their perceptions about such legislation. RESULTS Trade Marks Ordinance, Patents Ordinance, Trade Descriptions Ordinance, and Pharmacy and Poisons Ordinance were current legislative items combating counterfeit drugs. Sentencing criteria depended on: intention to deceive, quantity of seized drugs, presence of expected therapeutic effect or toxic ingredients, previous criminal records, cooperativeness with Customs officers, honest confessions, pleas of guilty, types of drugs, and precautionary measures to prevent sale of counterfeit drugs. Stakeholders’ perceptions were explored with respect to legislation regarding the scale and significance of the counterfeit drug problem, penalties and deterrents, drug-specific legislation and authority, and inspections and enforcement. CONCLUSIONS To plug the loopholes, a specific law with heavy penalties should be adopted. This could be supplemented by non-legal measures like education of judges, lawyers, and the public; publishing the names of offending pharmacies; and emphasising the role of pharmacists to the public.
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Affiliation(s)
- C W Lai
- The Jockey Club School of Public Health and Primary Care, Faculty of Medicine, Prince of Wales Hospital, The Chinese University of Hong Kong, Shatin, Hong Kong
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Abstract
The title complexes were doped into polycarbonate matrices together with triphenylamine, a hole-transport compound, in order to study their photosensitizing properties. Complexes based on 1 exhibited strong absorption in the visible spectrum due to the presence of a metal-ligand charge-transfer transition and were able to enhance the sensitivity in this region; the best enhancement was found when Ar is a p-flurophenyl group.
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Affiliation(s)
- L S Lam
- Department of Chemistry, University of Hong Kong, Pokfulam Road, Hong Kong
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Lin AWC, Chan KCW, Chan WK, Wong KH. Authors' reply. Hong Kong Med J 2013; 19:561. [PMID: 24310668] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/02/2023] Open
Affiliation(s)
- Ada W C Lin
- Special Preventive Programme, Centre for Health Protection, Department of Health, Kowloon Bay Health Centre, 9 Kai Yan Road, Kowloon Bay, Kowloon, Hong Kong
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Luk JKH, Chan WK, Ng WC, Chiu PKC, Ho C, Chan TC, Chan FHW. Mortality and health services utilisation among older people with advanced cognitive impairment living in residential care homes. Hong Kong Med J 2013; 19:518-24. [PMID: 24096360 DOI: 10.12809/hkmj133951] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
OBJECTIVES To study the demography, clinical characteristics, service utilisation, mortality, and predictors of mortality in older residential care home residents with advanced cognitive impairment. DESIGN Cohort longitudinal study. SETTING Residential care homes for the elderly in Hong Kong West. PARTICIPANTS Residents of such homes aged 65 years or more with advanced cognitive impairment. RESULTS In all, 312 such residential care home residents (71 men and 241 women) were studied. Their mean age was 88 (standard deviation, 8) years and their mean Barthel Index 20 score was 1.5 (standard deviation, 2.0). In all, 164 (53%) were receiving enteral feeding. Nearly all of them had urinary and bowel incontinence. Apart from Community Geriatric Assessment Team clinics, 119 (38%) of the residents attended other clinics outside their residential care homes. In all, 107 (34%) died within 1 year; those who died within 1 year used significantly more emergency and hospital services (P<0.001), and utilised more services from community care nurses for wound care (P=0.001), enteral feeding tube care (P=0.018), and urinary catheter care (P<0.001). Independent risk factors for 1-year mortality were active pressure sores (P=0.0037), enteral feeding (P=0.008), having a urinary catheter (P=0.0036), and suffering from chronic obstructive pulmonary disease (P=0.011). A history of pneumococcal vaccination was protective with respect to 1-year mortality (P=0.004). CONCLUSION Residents of residential care homes for the elderly with advanced cognitive impairment were frail, exhibited multiple co-morbidities and high mortality. They were frequent users of out-patient, emergency, and in-patient services. The development of end-of-life care services in residential care homes for the elderly is an important need for this group of elderly.
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Affiliation(s)
- James K H Luk
- Department of Medicine and Geriatrics, Fung Yiu King Hospital, 9 Sandy Bay Road, Pokfulam, Hong Kong
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Chan CK, Wong KH, Leung CC, Tam CM, Chan KCW, Pang KW, Chan WK, Mak IKY. Treatment outcomes after early initiation of antiretroviral therapy for human immunodeficiency virus-associated tuberculosis. Hong Kong Med J 2013; 19:474-83. [PMID: 23926173 DOI: 10.12809/hkmj133937] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
OBJECTIVE To evaluate the optimal timing for initiating antiretroviral therapy in patients with human immunodeficiency virus (HIV)-associated tuberculosis in Hong Kong. DESIGN Historical cohort. SETTING. Tuberculosis and Chest Service and Special Preventive Programme, Public Health Service Branch, Centre for Health Protection, Department of Health, Hong Kong. PATIENTS Consecutive patients with HIV-associated tuberculosis in a territory-wide TB-HIV registry encountered from 1996 to 2009. RESULTS Of the 260 antiretroviral therapy-naïve patients with HIV-associated tuberculosis, 32 (12%) had antiretroviral therapy initiated within 2 months after starting anti-tuberculosis treatment (early antiretroviral therapy). Early antiretroviral therapy was associated with a more favourable outcome (cure or treatment completion without relapse) at 24 months (91% vs 67%; P=0.007) than those with antiretroviral therapy started later or not initiated, and remained an independent predictor of a favourable outcome after adjustment for potential confounders. Adverse effects from anti-tuberculosis drugs tended to occur more frequently in patients with early antiretroviral therapy (13/32 or 41%) compared with the remainder (59/228 or 26%; P=0.08). A significantly higher proportion of patients in the former group experienced immune reconstitution inflammatory syndrome than in the latter group (7/32 or 22% vs 9/228 or 4%; P<0.001). There was no death attributable to immune reconstitution inflammatory syndrome. CONCLUSIONS Early initiation of antiretroviral therapy is associated with more favourable tuberculosis treatment outcomes in patients with HIV-associated tuberculosis with a low CD4 count (<200/µL). Drug co-toxicity and immune reconstitution inflammatory syndrome that may be increased by earlier initiation of antiretroviral therapy does not undermine tuberculosis treatment outcomes to a significant extent.
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Affiliation(s)
- C K Chan
- Tuberculosis and Chest Service, Public Health Service Branch, Centre for Health Protection, Department of Health, Hong Kong
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Lin AWC, Chan KCW, Chan WK, Wong KH. Tuberculin sensitivity testing and treatment of latent tuberculosis remains effective for tuberculosis control in human immunodeficiency virus-infected patients in Hong Kong. Hong Kong Med J 2013; 19:386-92. [PMID: 23926172 DOI: 10.12809/hkmj133892] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
OBJECTIVE To evaluate whether a policy to treat latent tuberculosis identified by annual tuberculin sensitivity testing is effective for tuberculosis control in human immunodeficiency virus-infected patients in Hong Kong. DESIGN Historical cohort study. SETTING Integrated Treatment Centre, Department of Health, Hong Kong. PATIENTS Patients infected with human immunodeficiency virus without a history of tuberculosis were offered annual tuberculin sensitivity testing, coupled with treatment of latent tuberculosis if they tested positive. All such patients were followed for new tuberculosis. RESULTS In all, 1154 patients on antiretroviral therapy, contributing to 5587 patient-years of observation, were analysed; 1032 patients (89%) received annual tuberculin sensitivity testing. Their baseline characteristics, including CD4 counts and other risk factors for tuberculosis, did not differ significantly from those who declined testing. The overall incidence rate of tuberculosis was 0.59 case per 100 patient-years. It was lower in those who received annual tuberculin sensitivity testing than those who did not (0.41 vs 3.85 per 100 patient-years; P<0.0001). Only a low baseline CD4 count and a history of tuberculin sensitivity testing were shown to be significant indicators of incident tuberculosis using multivariate analysis. The hazard ratio was 0.36 (95% confidence interval, 0.16-0.85; P=0.02) for those with a baseline CD4 count of 100/mm3 or above, and 0.26 (95% confidence interval, 0.08-0.77; P=0.016) for those who received annual tuberculin sensitivity testing. The incidence of tuberculosis was highest within 90 days of antiretroviral therapy initiation. CONCLUSION The established policy continues to be effective. The high risk of tuberculosis during the early period of antiretroviral therapy supports early use of tuberculin sensitivity testing. Alternatively, the strategy of universal isoniazid preventive therapy at antiretroviral therapy initiation could be studied for those with very low baseline CD4 counts.
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Affiliation(s)
- A W C Lin
- Integrated Treatment Centre, Special Preventive Programme, Centre for Health Protection, Department of Health, Hong Kong
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Lin AWC, Wong KH, Chan K, Chan WK. Accelerating prevention of mother-to-child transmission of HIV: ten-year experience of universal antenatal HIV testing programme in a low HIV prevalence setting in Hong Kong. AIDS Care 2013; 26:169-75. [PMID: 23869699 DOI: 10.1080/09540121.2013.819402] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Hong Kong has a low prevalence of HIV infection at less than 0.01%. Universal Antenatal HIV Testing Programme (UATP) was launched in all public antenatal units in September 2001. In 2008, voluntary rapid HIV testing was introduced in all public labour units to fill up the gap for pregnant women without HIV testing during the antenatal period. This study evaluated the performance of UATP and rapid HIV testing with indicators. From September 2001 to December 2011, process and outcome indicators for monitoring and evaluation were collected from the service providers in the form of monthly return of workload statistics and case-based statistics of each identified HIV-positive pregnancy via reporting forms. A total of 479,160 antenatal HIV tests and 2,675 rapid tests were performed in the study period. The acceptance rate for UATP and rapid HIV testing was 98% and 80.4% respectively. With the implementation of rapid HIV testing in January 2008, the proportion of pregnant women with HIV status discerned before delivery increased from 84.9% in 2006 to over 99.5% since 2008. The HIV prevalence in UATP and rapid HIV testing was 0.02% and 0.1% respectively. Fifty-three (68%) out of 78 HIV-infected pregnant women identified from the programme have delivered locally. Forty-three (81%) of them delivered by caesarean section and 50 (94%) of them were given antiretrovirals for intervention. Only three children born before the implementation of rapid HIV testing were HIV-infected. In conclusion, UATP and its rapid HIV testing component have been highly accepted and effective in the prevention of perinatal HIV transmission in Hong Kong.
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Affiliation(s)
- Ada W C Lin
- a Special Preventive Programme, Department of Health , Centre for Health Protection , Hong Kong , China
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Leung YH, Chan CMN, Ng AMC, Chan HT, Chiang MWL, Djurišić AB, Ng YH, Jim WY, Guo MY, Leung FCC, Chan WK, Au DTW. Antibacterial activity of ZnO nanoparticles with a modified surface under ambient illumination. Nanotechnology 2012; 23:475703. [PMID: 23103840 DOI: 10.1088/0957-4484/23/47/475703] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
In various practical applications, nanomaterials typically have functionalized surfaces. Yet, the studies of toxicity and antibacterial activity of functionalized nanoparticles are scarce. We investigated the effect of surface modifications on antibacterial activity of ZnO under ambient illumination, and we found that nanoparticles coated with different surface modifying reagents could exhibit higher or lower toxicity compared to bare ZnO, depending on the surface modifying reagent used. Different surface modifying reagent molecules resulted in differences in the release of Zn(2+) ions and the production of reactive oxygen species (ROS). However, the antibacterial activity did not correlate with the ROS levels or the Zn(2+) ion release. One of the surface-modified ZnO samples exhibited significantly lower Zn(2+) ion release while at the same time exhibiting improved antibacterial activity. In all cases, damage of the cell wall membranes and/or changes in the membrane permeability have been observed, together with the changes in ATR-FTIR spectra indicating differences in protein conformation. Mechanisms of antibacterial activity are discussed.
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Affiliation(s)
- Y H Leung
- Department of Physics, The University of Hong Kong, Hong Kong
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Nguyen LS, Jolly L, Shoubridge C, Chan WK, Huang L, Laumonnier F, Raynaud M, Hackett A, Field M, Rodriguez J, Srivastava AK, Lee Y, Long R, Addington AM, Rapoport JL, Suren S, Hahn CN, Gamble J, Wilkinson MF, Corbett MA, Gecz J. Transcriptome profiling of UPF3B/NMD-deficient lymphoblastoid cells from patients with various forms of intellectual disability. Mol Psychiatry 2012; 17:1103-15. [PMID: 22182939 PMCID: PMC4281019 DOI: 10.1038/mp.2011.163] [Citation(s) in RCA: 77] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2011] [Revised: 09/27/2011] [Accepted: 10/24/2011] [Indexed: 11/09/2022]
Abstract
The nonsense-mediated mRNA decay (NMD) pathway was originally discovered by virtue of its ability to rapidly degrade aberrant mRNAs with premature termination codons. More recently, it was shown that NMD also directly regulates subsets of normal transcripts, suggesting that NMD has roles in normal biological processes. Indeed, several NMD factors have been shown to regulate neurological events (for example, neurogenesis and synaptic plasticity) in numerous vertebrate species. In man, mutations in the NMD factor gene UPF3B, which disrupts a branch of the NMD pathway, cause various forms of intellectual disability (ID). Using Epstein Barr virus-immortalized B cells, also known as lymphoblastoid cell lines (LCLs), from ID patients that have loss-of-function mutations in UPF3B, we investigated the genome-wide consequences of compromised NMD and the role of NMD in neuronal development and function. We found that ~5% of the human transcriptome is impacted in UPF3B patients. The UPF3B paralog, UPF3A, is stabilized in all UPF3B patients, and partially compensates for the loss of UPF3B function. Interestingly, UPF3A protein, but not mRNA, was stabilised in a quantitative manner that inversely correlated with the severity of patients' phenotype. This suggested that the ability to stabilize the UPF3A protein is a crucial modifier of the neurological symptoms due to loss of UPF3B. We also identified ARHGAP24, which encodes a GTPase-activating protein, as a canonical target of NMD, and we provide evidence that deregulation of this gene inhibits axon and dendrite outgrowth and branching. Our results demonstrate that the UPF3B-dependent NMD pathway is a major regulator of the transcriptome and that its targets have important roles in neuronal cells.
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Affiliation(s)
- LS Nguyen
- Department of Paediatrics, University of Adelaide, Adelaide, SA, Australia
- Department of Genetic Medicine, SA Pathology, Adelaide, SA, Australia
| | - L Jolly
- Department of Genetic Medicine, SA Pathology, Adelaide, SA, Australia
| | - C Shoubridge
- Department of Paediatrics, University of Adelaide, Adelaide, SA, Australia
- Department of Genetic Medicine, SA Pathology, Adelaide, SA, Australia
| | - WK Chan
- Department of Bioinformatics and Computational Biology, University of Texas M.D. Anderson Cancer Center, Houston, TX, USA
| | - L Huang
- Department of Reproductive Medicine, University of California, San Diego, CA, USA
| | - F Laumonnier
- INSERM, U930, Tours, France
- CNRS, ERL3106, Tours, France
- University Francois-Rabelais, UMR ‘Imaging and Brain’, Tours, France
| | - M Raynaud
- INSERM, U930, Tours, France
- University Francois-Rabelais, UMR ‘Imaging and Brain’, Tours, France
- CHRU de Tours, Service de Genetique, Tours, France
| | - A Hackett
- GOLD Service, Hunter Genetics, Newcastle, Australia
| | - M Field
- GOLD Service, Hunter Genetics, Newcastle, Australia
| | - J Rodriguez
- J.C. Self Research Institute, Greenwood Genetic Centre, Greenwood, SC, USA
| | - AK Srivastava
- J.C. Self Research Institute, Greenwood Genetic Centre, Greenwood, SC, USA
| | - Y Lee
- Child Psychiatry Branch, National Institute of Mental Health, Bethesda, MD, USA
| | - R Long
- Child Psychiatry Branch, National Institute of Mental Health, Bethesda, MD, USA
| | - AM Addington
- Child Psychiatry Branch, National Institute of Mental Health, Bethesda, MD, USA
| | - JL Rapoport
- Child Psychiatry Branch, National Institute of Mental Health, Bethesda, MD, USA
| | - S Suren
- Human Developmental Biology Resource, Neural Development Unit, UCL Institute of Child Health, London, UK
| | - CN Hahn
- Department of Molecular Pathology, Centre for Cancer Biology, SA Pathology, Adelaide, SA, Australia
| | - J Gamble
- Centenary Institute of Cancer Medicine & Cell Biology, University of Sydney, NSW, Australia
| | - MF Wilkinson
- Department of Reproductive Medicine, University of California, San Diego, CA, USA
| | - MA Corbett
- Department of Genetic Medicine, SA Pathology, Adelaide, SA, Australia
| | - J Gecz
- Department of Paediatrics, University of Adelaide, Adelaide, SA, Australia
- Department of Genetic Medicine, SA Pathology, Adelaide, SA, Australia
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Ng A, Ho CL, Fung MK, Sun YC, Shao SY, Fu YY, Ng AMC, Li CH, Cheung WK, Leung YH, Djurišić AB, Wang Q, He Z, Wang X, Chan WK, Xie ZY, Zapien JA, To CH, Wong WY. Metal-Free and Metallated Polymers: Properties and Photovoltaic Performance. MACROMOL CHEM PHYS 2012. [DOI: 10.1002/macp.201100686] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Lieu CF, Chan WK, Ooi KT. Experimental investigation of the reciprocating ball pump (RBP). Med Eng Phys 2011; 34:1101-8. [PMID: 22205041 DOI: 10.1016/j.medengphy.2011.11.016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2011] [Revised: 11/05/2011] [Accepted: 11/17/2011] [Indexed: 10/14/2022]
Abstract
This paper presents experimental investigations of a novel miniature reciprocating ball pump (RBP) as a potential infusion pump or drug delivery system. The objectives of this study are to validate the RBP's operational principle and to evaluate its performance. In the tests, the basic functionality of the pump has been established at different pumping frequencies ranging from 1.667 Hz (100 rpm) to 4.167 Hz (250 rpm) against different pressure heads ranging from 0 mmH(2)O and 100 mmH(2)O. In addition, experimental results show that the RBP can deliver a higher flow rate with a volumetric efficiency of 120% as compared to a conventional single acting reciprocating pump running under the same operating conditions.
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Affiliation(s)
- C F Lieu
- School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore.
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Zhan H, Wong WY, Ng A, Djurišić AB, Chan WK. Synthesis, characterization and photovoltaic properties of platinum-containing poly(aryleneethynylene) polymers with phenanthrenyl-imidazole moiety. J Organomet Chem 2011. [DOI: 10.1016/j.jorganchem.2011.07.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Zhan H, Lamare S, Ng A, Kenny T, Guernon H, Chan WK, Djurišić AB, Harvey PD, Wong WY. Synthesis and Photovoltaic Properties of New Metalloporphyrin-Containing Polyplatinyne Polymers. Macromolecules 2011. [DOI: 10.1021/ma2006206] [Citation(s) in RCA: 116] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Hongmei Zhan
- Institute of Molecular Functional Materials (Areas of Excellence Scheme, University Grants Committee, Hong Kong) and Department of Chemistry and Centre for Advanced Luminescence Materials, Hong Kong Baptist University, Kowloon Tong, Kowloon, Hong Kong, P.R. China
| | - Simon Lamare
- Département de Chimie, Université de Sherbrooke, 2550 Boul. Université, Sherbrooke, PQ, J1K 2R1 Canada
| | - Annie Ng
- Department of Physics, The University of Hong Kong, Pokfulam Road, Hong Kong, P.R. China
| | - Tommy Kenny
- Département de Chimie, Université de Sherbrooke, 2550 Boul. Université, Sherbrooke, PQ, J1K 2R1 Canada
| | - Hannah Guernon
- Département de Chimie, Université de Sherbrooke, 2550 Boul. Université, Sherbrooke, PQ, J1K 2R1 Canada
| | - Wai-Kin Chan
- Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong, P.R. China
| | - Aleksandra B. Djurišić
- Department of Physics, The University of Hong Kong, Pokfulam Road, Hong Kong, P.R. China
| | - Pierre D. Harvey
- Département de Chimie, Université de Sherbrooke, 2550 Boul. Université, Sherbrooke, PQ, J1K 2R1 Canada
| | - Wai-Yeung Wong
- Institute of Molecular Functional Materials (Areas of Excellence Scheme, University Grants Committee, Hong Kong) and Department of Chemistry and Centre for Advanced Luminescence Materials, Hong Kong Baptist University, Kowloon Tong, Kowloon, Hong Kong, P.R. China
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Affiliation(s)
- C-L Ho
- Department of Nuclear Medicine & PET, Hong Kong Sanatorium & Hospital, Hong Kong, China
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Chan CK, Alvarez Bognar F, Wong KH, Leung CC, Tam CM, Chan KCW, Ho CF, Chan WK, Mak IKY. The epidemiology and clinical manifestations of human immunodeficiency virus-associated tuberculosis in Hong Kong. Hong Kong Med J 2010; 16:192-198. [PMID: 20519755] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/29/2023] Open
Abstract
OBJECTIVE To evaluate the epidemiology and clinical manifestations of human immunodeficiency virus-associated tuberculosis in Hong Kong. DESIGN Retrospective study. SETTING Tuberculosis and Chest Service and Special Preventive Programme, Public Health Services Branch, Centre for Health Protection, Department of Health, Hong Kong Special Administrative Region. PATIENTS Cases reported to the TB/HIV Registry jointly kept by the Tuberculosis and Chest Service and Special Preventive Programme from 1996 to 2006 were reviewed. The Registry includes cases of human immunodeficiency virus-associated tuberculosis diagnosed in the two services, and cases referred from regional hospitals under the Hong Kong Hospital Authority and the private sector. RESULTS Tuberculosis has become an increasingly important acquired immunodeficiency syndrome-defining illness in Hong Kong, and overtook Pneumocystis jiroveci pneumonia for the first time as the most common primary acquired immunodeficiency syndrome-defining illness in 2005 (accounting for 39% and 31% of all such illnesses, respectively in that year). The presentation of human immunodeficiency virus-associated tuberculosis is often atypical. In these patients moreover, there was a slightly higher rate of multidrug-resistant tuberculosis (2%) than in the general population (range, 0.7-1.5%). CONCLUSIONS Programmes for the provider-initiated human immunodeficiency virus testing policy to reduce diagnostic delays should continue and be enhanced. Continual surveillance of both conditions is imperative, especially in view of a possible link between human immunodeficiency virus and multidrug-resistant tuberculosis.
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Affiliation(s)
- C K Chan
- Tuberculosis and Chest Service, Public Health Services Branch, Centre for Health Protection, Department of Health, Hong Kong.
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Wang XZ, Wang Q, Yan L, Wong WY, Cheung KY, Ng A, Djurišić AB, Chan WK. Very-Low-Bandgap Metallopolyynes of Platinum with a Cyclopentadithiophenone Ring for Organic Solar Cells Absorbing Down to the Near-Infrared Spectral Region. Macromol Rapid Commun 2010; 31:861-7. [DOI: 10.1002/marc.200900885] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2009] [Indexed: 11/10/2022]
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Abstract
The T-cell receptor (TCR) and immunoglobulin (Ig) genes are unique among vertebrate genes in that they undergo programmed rearrangement, a process that allows them to generate an enormous array of receptors with different antigen specificities. While crucial for immune function, this rearrangement mechanism is highly error prone, often generating frameshift or nonsense mutations that render the rearranged TCR and Ig genes defective. Such frame-disrupting mutations have been reported to increase the level of TCRbeta and Igmicro pre-mRNA, suggesting the hypothesis that RNA processing is blocked when frame disruption is sensed. Using a chimeric gene that contains TCRbeta sequences conferring this upregulatory response, we provide evidence that pre-mRNA upregulation is neither frame- nor translation-dependent; instead, several lines of evidence suggested that it is the result of disrupted cis elements necessary for efficient RNA splicing. In particular, we identify the rearranging VDJ(beta) exon as being uniquely densely packed with exonic-splicing enhancers (ESEs), rendering this exon hypersensitive to mutational disruption. As the chimeric gene that we developed for these studies generates unusually stable nuclear pre-mRNAs that accumulate when challenged with ESE mutations, we suggest it can be used as a sensitive in vivo system to identify and characterize ESEs.
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Affiliation(s)
- J Saadi Imam
- Department of Biochemistry and Molecular Biology, The University of Texas M.D. Anderson Cancer Center, 1515 Holcombe Blvd., Houston, TX 77030-4009, USA
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Ng AMC, Xi YY, Hsu YF, Djurisić AB, Chan WK, Gwo S, Tam HL, Cheah KW, Fong PWK, Lui HF, Surya C. GaN/ZnO nanorod light emitting diodes with different emission spectra. Nanotechnology 2009; 20:445201. [PMID: 19801783 DOI: 10.1088/0957-4484/20/44/445201] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Light emitting diodes (LEDs) consisting of p-GaN epitaxial films and n-ZnO nanorods have been fabricated and characterized. The rectifying behavior and emission spectra were strongly dependent on the electronic properties of both GaN film and ZnO nanorods. Light emission under both forward and reverse bias was obtained in all cases, and emission spectra could be changed by annealing the ZnO nanorods. The emission spectra could be further tuned by using a GaN LED epiwafer as a substrate. Both forward and backward diode behavior has been observed and the emission spectra were significantly affected by both the properties of the GaN substrate and the annealing conditions for the ZnO nanorods.
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Affiliation(s)
- A M C Ng
- Department of Physics, The University of Hong Kong, Pokfulam Road, Hong Kong, People's Republic of China
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Chan WK, Bhalla AD, Le Hir H, Nguyen LS, Huang L, Gécz J, Wilkinson MF. A UPF3-mediated regulatory switch that maintains RNA surveillance. Nat Struct Mol Biol 2009; 16:747-53. [PMID: 19503078 DOI: 10.1038/nsmb.1612] [Citation(s) in RCA: 93] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2008] [Accepted: 04/24/2009] [Indexed: 02/05/2023]
Abstract
Nonsense-mediated decay (NMD) is an RNA decay pathway that downregulates aberrant mRNAs and a subset of normal mRNAs. The regulation of NMD is poorly understood. Here we identify a regulatory mechanism acting on two related UPF (up-frameshift) factors crucial for NMD: UPF3A and UPF3B. This regulatory mechanism, which reduces the level of UPF3A in response to the presence of UPF3B, is relieved in individuals harboring UPF3B mutations, leading to strongly increased steady-state levels of UPF3A. UPF3A compensates for the loss of UPF3B by regulating several NMD target transcripts, but it can also impair NMD, as it competes with the stronger NMD activator UPF3B for binding to the essential NMD factor UPF2. This deleterious effect of UPF3A protein is prevented by its destabilization using a conserved UPF3B-dependent mechanism. Together, our results suggest that UPF3A levels are tightly regulated by a post-transcriptional switch to maintain appropriate levels of NMD substrates in cells containing different levels of UPF3B.
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Affiliation(s)
- Wai-Kin Chan
- Department of Biochemistry and Molecular Biology, The University of Texas M.D. Anderson Cancer Center, Houston, Texas, USA
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Abstract
T-cell receptor-beta (TCRbeta) genes naturally acquire premature termination codons (PTCs) as a result of programmed gene rearrangements. PTC-bearing TCRbeta transcripts are dramatically down-regulated to protect T-cells from the deleterious effects of the truncated proteins that would otherwise be produced. Here we provide evidence that two responses collaborate to elicit this dramatic down-regulation. One is rapid mRNA decay triggered by the nonsense-mediated decay (NMD) RNA surveillance pathway. We demonstrate that this occurs in highly purified nuclei lacking detectable levels of three different cytoplasmic markers, but containing an outer nuclear membrane marker, suggesting that decay occurs either in the nucleoplasm or at the outer nuclear membrane. The second response is a dramatic partitioning shift in the nuclear fraction-to-cytoplasmic fraction mRNA ratio that results in few TCRbeta transcripts escaping to the cytoplasmic fraction of cells. Analysis of TCRbeta mRNA kinetics after either transcriptional repression or induction suggested that this nonsense codon-induced partitioning shift (NIPS) response is not the result of cytoplasmic NMD but instead reflects retention of PTC(+) TCRbeta mRNA in the nuclear fraction of cells. We identified TCRbeta sequences crucial for NIPS but found that NIPS is not exclusively a property of TCRbeta transcripts, and we identified non-TCRbeta sequences that elicit NIPS. RNA interference experiments indicated that NIPS depends on the NMD factors UPF1 and eIF4AIII but not the NMD factor UPF3B. We propose that NIPS collaborates with NMD to retain and degrade a subset of PTC(+) transcripts at the outer nuclear membrane and/or within the nucleoplasm.
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Affiliation(s)
- Angela D Bhalla
- Department of Biochemistry and Molecular Biology, University of Texas M.D. Anderson Cancer Center, Houston, Texas 77030-4009, USA
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Zhou L, Chan WK, Xu N, Xiao K, Luo H, Luo KQ, Chang DC. Tanshinone IIA, an isolated compound from Salvia miltiorrhiza Bunge, induces apoptosis in HeLa cells through mitotic arrest. Life Sci 2008; 83:394-403. [PMID: 18721815 DOI: 10.1016/j.lfs.2008.07.011] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2007] [Revised: 06/27/2008] [Accepted: 07/04/2008] [Indexed: 10/21/2022]
Abstract
AIMS Tanshinone IIA (Tan IIA) is a compound isolated from Salvia miltiorrhiza Bunge (Danshen). The aim of this study is to investigate the mechanisms of its anti-cancer effect. MAIN METHODS To clearly delineate the cell cycle-dependent effects of Tan IIA, we used either synchronized cells or single living cell analysis to conduct our studies. Subcellular fractionation, Western blot analysis, immuno-fluorescence staining and FACS analysis were also employed in our study. KEY FINDINGS We found that Tan IIA could arrest cancer cells in mitosis by disrupting the mitotic spindle and subsequently triggered cells to enter apoptosis through the mitochondria-dependent apoptotic pathway. Thus, Tan IIA could selectively kill mitotic cells over interphase cells. In comparison with other existing anti-cancer drugs that cause mitotic arrest by interfering with the microtubule structure (such as vincristine or taxol), Tan IIA destroyed only the mitotic spindle during the M phase but not the microtubule structure in interphase cells. Furthermore, Tan IIA could trigger the mitotic arrested cells to enter apoptosis faster than vincristine or taxol. SIGNIFICANCE Since Tan IIA can selectively induce cancer cells to enter apoptosis through mitotic arrest, it has the potential to be developed into an anti-cancer drug.
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Affiliation(s)
- Lingli Zhou
- Department of Biology, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
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Wang XZ, Wong WY, Cheung KY, Fung MK, Djurišić AB, Chan WK. Polymer solar cells based on very narrow-bandgap polyplatinynes with photocurrents extended into the near-infrared region. Dalton Trans 2008:5484-94. [DOI: 10.1039/b803467b] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Wong WY, Wang XZ, He Z, Chan KK, Djurišić AB, Cheung KY, Yip CT, Ng AMC, Xi YY, Mak CSK, Chan WK. Tuning the Absorption, Charge Transport Properties, and Solar Cell Efficiency with the Number of Thienyl Rings in Platinum-Containing Poly(aryleneethynylene)s. J Am Chem Soc 2007; 129:14372-80. [DOI: 10.1021/ja074959z] [Citation(s) in RCA: 228] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Wai-Yeung Wong
- Contribution from the Department of Chemistry and Centre for Advanced Luminescence Materials, Hong Kong Baptist University, Waterloo Road, Kowloon Tong, Hong Kong, P. R. China, Key Laboratory of Environmentally Friendly Chemistry and Applications of Ministry of Education, College of Chemistry, Xiangtan University, Xiangtan 411105, Hunan Province, P. R. China, and Departments of Chemistry and Physics, The University of Hong Kong, Pokfulam Road, Hong Kong, P. R. China
| | - Xing-Zhu Wang
- Contribution from the Department of Chemistry and Centre for Advanced Luminescence Materials, Hong Kong Baptist University, Waterloo Road, Kowloon Tong, Hong Kong, P. R. China, Key Laboratory of Environmentally Friendly Chemistry and Applications of Ministry of Education, College of Chemistry, Xiangtan University, Xiangtan 411105, Hunan Province, P. R. China, and Departments of Chemistry and Physics, The University of Hong Kong, Pokfulam Road, Hong Kong, P. R. China
| | - Ze He
- Contribution from the Department of Chemistry and Centre for Advanced Luminescence Materials, Hong Kong Baptist University, Waterloo Road, Kowloon Tong, Hong Kong, P. R. China, Key Laboratory of Environmentally Friendly Chemistry and Applications of Ministry of Education, College of Chemistry, Xiangtan University, Xiangtan 411105, Hunan Province, P. R. China, and Departments of Chemistry and Physics, The University of Hong Kong, Pokfulam Road, Hong Kong, P. R. China
| | - Kwok-Kwan Chan
- Contribution from the Department of Chemistry and Centre for Advanced Luminescence Materials, Hong Kong Baptist University, Waterloo Road, Kowloon Tong, Hong Kong, P. R. China, Key Laboratory of Environmentally Friendly Chemistry and Applications of Ministry of Education, College of Chemistry, Xiangtan University, Xiangtan 411105, Hunan Province, P. R. China, and Departments of Chemistry and Physics, The University of Hong Kong, Pokfulam Road, Hong Kong, P. R. China
| | - Aleksandra B. Djurišić
- Contribution from the Department of Chemistry and Centre for Advanced Luminescence Materials, Hong Kong Baptist University, Waterloo Road, Kowloon Tong, Hong Kong, P. R. China, Key Laboratory of Environmentally Friendly Chemistry and Applications of Ministry of Education, College of Chemistry, Xiangtan University, Xiangtan 411105, Hunan Province, P. R. China, and Departments of Chemistry and Physics, The University of Hong Kong, Pokfulam Road, Hong Kong, P. R. China
| | - Kai-Yin Cheung
- Contribution from the Department of Chemistry and Centre for Advanced Luminescence Materials, Hong Kong Baptist University, Waterloo Road, Kowloon Tong, Hong Kong, P. R. China, Key Laboratory of Environmentally Friendly Chemistry and Applications of Ministry of Education, College of Chemistry, Xiangtan University, Xiangtan 411105, Hunan Province, P. R. China, and Departments of Chemistry and Physics, The University of Hong Kong, Pokfulam Road, Hong Kong, P. R. China
| | - Cho-Tung Yip
- Contribution from the Department of Chemistry and Centre for Advanced Luminescence Materials, Hong Kong Baptist University, Waterloo Road, Kowloon Tong, Hong Kong, P. R. China, Key Laboratory of Environmentally Friendly Chemistry and Applications of Ministry of Education, College of Chemistry, Xiangtan University, Xiangtan 411105, Hunan Province, P. R. China, and Departments of Chemistry and Physics, The University of Hong Kong, Pokfulam Road, Hong Kong, P. R. China
| | - Alan Man-Ching Ng
- Contribution from the Department of Chemistry and Centre for Advanced Luminescence Materials, Hong Kong Baptist University, Waterloo Road, Kowloon Tong, Hong Kong, P. R. China, Key Laboratory of Environmentally Friendly Chemistry and Applications of Ministry of Education, College of Chemistry, Xiangtan University, Xiangtan 411105, Hunan Province, P. R. China, and Departments of Chemistry and Physics, The University of Hong Kong, Pokfulam Road, Hong Kong, P. R. China
| | - Yan Yan Xi
- Contribution from the Department of Chemistry and Centre for Advanced Luminescence Materials, Hong Kong Baptist University, Waterloo Road, Kowloon Tong, Hong Kong, P. R. China, Key Laboratory of Environmentally Friendly Chemistry and Applications of Ministry of Education, College of Chemistry, Xiangtan University, Xiangtan 411105, Hunan Province, P. R. China, and Departments of Chemistry and Physics, The University of Hong Kong, Pokfulam Road, Hong Kong, P. R. China
| | - Chris S. K. Mak
- Contribution from the Department of Chemistry and Centre for Advanced Luminescence Materials, Hong Kong Baptist University, Waterloo Road, Kowloon Tong, Hong Kong, P. R. China, Key Laboratory of Environmentally Friendly Chemistry and Applications of Ministry of Education, College of Chemistry, Xiangtan University, Xiangtan 411105, Hunan Province, P. R. China, and Departments of Chemistry and Physics, The University of Hong Kong, Pokfulam Road, Hong Kong, P. R. China
| | - Wai-Kin Chan
- Contribution from the Department of Chemistry and Centre for Advanced Luminescence Materials, Hong Kong Baptist University, Waterloo Road, Kowloon Tong, Hong Kong, P. R. China, Key Laboratory of Environmentally Friendly Chemistry and Applications of Ministry of Education, College of Chemistry, Xiangtan University, Xiangtan 411105, Hunan Province, P. R. China, and Departments of Chemistry and Physics, The University of Hong Kong, Pokfulam Road, Hong Kong, P. R. China
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Chang YF, Chan WK, Imam JS, Wilkinson MF. Alternatively Spliced T-cell Receptor Transcripts Are Up-regulated in Response to Disruption of Either Splicing Elements or Reading Frame. J Biol Chem 2007; 282:29738-47. [PMID: 17693403 DOI: 10.1074/jbc.m704372200] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Nonsense mutations create premature termination codons (PTCs), leading to the generation of truncated proteins, some of which have deleterious gain-of-function or dominant-negative activity. Protecting cells from such aberrant proteins is non-sense-mediated decay (NMD), an RNA surveillance pathway that degrades transcripts harboring PTCs. A second response to nonsense mutations is the up-regulation of alternatively spliced transcripts that skip the PTC. This nonsense-associated altered splicing (NAS) response has the potential to rescue protein function, but the mechanism by which it is triggered has been controversial. Some studies suggest that, like NMD, NAS is triggered as a result of nonsense mutations disrupting reading frame, whereas other studies suggest that NAS is triggered when nonsense mutations disrupt exonic splicing enhancers (ESEs). Using T-cell receptor-beta (TCRbeta), which naturally acquires PTCs at high frequency, we provide evidence that both mechanisms act on a single type of mRNA. Mutations that disrupt consensus ESE sites up-regulated an alternatively spliced TCRbeta transcript that skipped the mutations independently of reading frame disruption and the NMD factor UPF1. In contrast, reading frame-disrupting mutations that did not disrupt consensus ESE sites elicited UPF1-dependent up-regulation of the alternatively spliced TCRbeta transcript. Restoration of reading frame prevented this up-regulation. Our results suggest that the response of an mRNA to a nonsense mutation depends on its context.
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Affiliation(s)
- Yao-Fu Chang
- Department of Biochemistry and Molecular Biology, The University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030, USA
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Tam KH, Cheung CK, Leung YH, Djurisić AB, Ling CC, Beling CD, Fung S, Kwok WM, Chan WK, Phillips DL, Ding L, Ge WK. Defects in ZnO nanorods prepared by a hydrothermal method. J Phys Chem B 2007; 110:20865-71. [PMID: 17048900 DOI: 10.1021/jp063239w] [Citation(s) in RCA: 201] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
ZnO nanorod arrays were fabricated using a hydrothermal method. The nanorods were studied by scanning electron microscopy, photoluminescence (PL), time-resolved PL, X-ray photoelectron spectroscopy, and positron annihilation spectroscopy before and after annealing in different environments and at different temperatures. Annealing atmosphere and temperature had significant effects on the PL spectrum, while in all cases the positron diffusion length and PL decay times were increased. We found that, while the defect emission can be significantly reduced by annealing at 200 degrees C, the rods still have large defect concentrations as confirmed by their low positron diffusion length and short PL decay time constants.
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Affiliation(s)
- K H Tam
- Department of Physics, The University of Hong Kong, Pokfulam Road, Hong Kong
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Wong WY, Wang XZ, He Z, Djurisić AB, Yip CT, Cheung KY, Wang H, Mak CSK, Chan WK. Metallated conjugated polymers as a new avenue towards high-efficiency polymer solar cells. Nat Mater 2007; 6:521-7. [PMID: 17496897 DOI: 10.1038/nmat1909] [Citation(s) in RCA: 321] [Impact Index Per Article: 18.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2007] [Accepted: 04/11/2007] [Indexed: 05/15/2023]
Abstract
Bulk heterojunction solar cells have been extensively studied owing to their great potential for cost-effective photovoltaic devices. Although recent advances resulted in the fabrication of poly(3-hexylthiophene) (P3HT)/fullerene derivative based solar cells with efficiencies in the range 4.4-5.0%, theoretical calculations predict that the development of novel donor materials with a lower bandgap is required to exceed the power-conversion efficiency of 10%. However, all of the lower bandgap polymers developed so far have failed to reach the efficiency of P3HT-based cells. To address this issue, we synthesized a soluble, intensely coloured platinum metallopolyyne with a low bandgap of 1.85 eV. The solar cells, containing metallopolyyne/fullerene derivative blends as the photoactive material, showed a power-conversion efficiency with an average of 4.1%, without annealing or the use of spacer layers needed to achieve comparable efficiency with P3HT. This clearly demonstrates the potential of metallated conjugated polymers for efficient photovoltaic devices.
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Affiliation(s)
- Wai-Yeung Wong
- Department of Chemistry, Hong Kong Baptist University, Waterloo Road, Kowloon Tong, Hong Kong, PR China.
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Yau T, Leong CH, Chan WK, Chan JK, Liang RHS, Epstein RJ. A case of mixed adult Wilms' tumour and angiosarcoma responsive to carboplatin, etoposide and vincristine (CEO). Cancer Chemother Pharmacol 2007; 61:717-20. [PMID: 17571263 DOI: 10.1007/s00280-007-0529-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2007] [Accepted: 05/14/2007] [Indexed: 12/31/2022]
Abstract
Here we report an unusual case of mixed Wilms' tumour and angiosarcoma in a 38-year-old female patient who presented with haematuria and right lower back pain. A computed tomographic (CT) scan confirmed a massive renal tumour associated with extensive retroperitoneal lymph node involvement, bony metastases and a right hip fracture. She was initially managed with palliative nephrectomy, which was followed by rapid postoperative deterioration. Histopathology revealed differentiated adult Wilms' tumour with renal angiosarcoma, whereas the pathology of the para-aortic lymph node and bone metastasis revealed angiosarcoma only. In view of her cachexia and cytopaenia, emergency chemotherapy was initiated using a modified regimen of carboplatin, etoposide and vincristine (CEO) in preference to the more traditional but less well-tolerated VAC (vincristine, actinomycin D, cyclophosphamide). Four cycles of this protocol yielded a dramatic response on re-staging CT scan. This case suggests that highly angiogenic tumours such as angiosarcoma may be effectively palliated using agents usually reserved for refractory Wilms' tumour, and supports the view that adult Wilms' tumour is more sensitive to such agents.
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Affiliation(s)
- Thomas Yau
- Division of Haematology/Oncology, University Department of Medicine, Room 405, Professorial Block, Queen Mary Hospital, Pokfulam Rd, Pokfulam, Hong Kong.
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Abstract
Patients newly attending the government HIV clinic in Hong Kong were studied for the prevalence and characteristics of recent HIV infection, which was defined as having a negative HIV antibody test and/or seroconversion illness within one year of a first positive antibody result. Fifty-nine (12.0%) of 492 HIV-positive patients first seen from 2001 to 2004 were determined to be recently infected. This likely represented the lower bound of the real situation. Compared with non-recent infections on univariate analysis, recent cases were more likely to be men who have sex with men (OR 2.23; 95%CI, 1.23-4.05), never married (OR 1.96; 95%CI, 1.03-3.89), had tertiary or above education (OR 3.93; 95%CI, 1.65-10.09) and with a baseline CD4>=500 cells/ul (OR 3.65; 95%CI, 1.87-6.93). Upon multivariate analysis, tertiary or above education (adjusted OR 4.23; 95%CI, 1.76-10.16) and CD4>=500 cells/ul at diagnosis (adjusted OR 3.58; 95%CI, 1.88-6.84) remained independent variables. HIV clinics are feasible settings for collecting epidemiological information of on-going infection. Differences in the profile between recent and non-recent cases may shed light on targeting efforts to prevent new HIV infections.
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Affiliation(s)
- W K Chan
- Integrated Treatment Centre, Special Preventive Programme, Centre for Health Protection, Department of Health, Hong Kong
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