1
|
Mok KH. Impact of COVID-19 on Higher Education: Critical Reflections. High Educ Policy 2022; 35:563-567. [PMID: 35971428 PMCID: PMC9365678 DOI: 10.1057/s41307-022-00285-x] [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] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
This Special Issue has chosen the major focus to examine how the COVID-19 pandemic has affected higher education development and governance. The collection of articles in this Special Issue is organized with three key sub-themes, namely, student mobility, teaching and student learning, and university governance. Papers selected in this Issue were presented at different international conferences examining how the outbreak of the COVID-19 pandemic in late 2019 has affected higher education development from international and comparative perspectives. During the international research events, authors contributing their papers to this Special Issue indeed benefitted from the exchanges and dialogues from international peers. Drawing insights from the papers collected in this Special Issue, this introductory article concludes by drawing the implications for future development of international education.
Collapse
Affiliation(s)
- Ka Ho Mok
- Lingnan University, Tuen Mun, Hong Kong, China
| |
Collapse
|
2
|
Mok KH, Xiong W, Ke G. Reimagining Higher Education in the Post-COVID-19 Era: Chinese Students' Desires for Overseas Learning and Implications for University Governance. High Educ Policy 2022; 35:591-609. [PMID: 35634194 PMCID: PMC9127035 DOI: 10.1057/s41307-022-00273-1] [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] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Neither world leaders nor leading medical professionals would have anticipated the adverse impacts of the global health crisis resulting from the outbreak of the COVID-19 pandemic on multifaceted aspects of contemporary society. Set against the broader political economy context, this Special Issue focuses on examining the impacts of the present global health crisis on higher education development. Addressing the major objective of the Special Issue, this article chooses the theme of reimagining higher education in the post-COVID-19 era, critically examining Chinese students' desires and motivations for overseas learning. Based upon a few waves of surveys conducted since 2020, after the outbreak of the pandemic, this article assesses the impacts of the unprecedented global health crisis on Chinese students' future overseas study plans. Having experienced various forms of disruption during the COVID-19 period, this article also critically reimagines higher education development in the post-COVID-19 era.
Collapse
Affiliation(s)
- Ka Ho Mok
- Institute of Policy Studies, Lingnan University, Hong Kong SAR, China
| | - Weiyan Xiong
- Institute of Policy Studies, Lingnan University, Hong Kong SAR, China
| | - Guoguo Ke
- Institute of Policy Studies, Lingnan University, Hong Kong SAR, China
| |
Collapse
|
3
|
Lin K, Mumtaz A, Rahaman MA, Mok KH. Corrigendum: Social Quarantine and Its Four Modes: Conceptional Exploration and the Theoretical Construction of the Policies Against COVID-19. Front Public Health 2021; 9:793721. [PMID: 34900926 PMCID: PMC8656969 DOI: 10.3389/fpubh.2021.793721] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Accepted: 11/03/2021] [Indexed: 12/03/2022] Open
Affiliation(s)
- Ka Lin
- College of Public Administration, Zhejiang University, Hangzhou, China.,Institute of Policy Studies, Lingnan University, Hong Kong SAR, China
| | - Ayesha Mumtaz
- College of Public Administration, Zhejiang University, Hangzhou, China
| | | | - Ka Ho Mok
- Institute of Policy Studies, Lingnan University, Hong Kong SAR, China
| |
Collapse
|
4
|
Ho JCS, Ambite I, Mok KH, Babjuk M, Svanborg C. A scientific journey from discovery to validation of efficacy in cancer patients: HAMLET and alpha1-oleate. Mol Cell Oncol 2021; 8:1974278. [PMID: 34859140 PMCID: PMC8632289 DOI: 10.1080/23723556.2021.1974278] [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] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The protein-lipid complex alpha1-oleate, derived from HAMLET (Human Alpha-lactalbumin Made LEthal to Tumor cells), is identified as a molecular entity with significant therapeutic potential. Structural characterization of the complex and results of a successful placebo-controlled clinical trial are presented.
Collapse
Affiliation(s)
- James C S Ho
- Division of Microbiology, Immunology and Glycobiology, Department of Laboratory Medicine, Faculty of Medicine, Lund University, Lund, Sweden.,Singapore Centre for Environmental Life Sciences Engineering (SCELSE), Nanyang Technological University, Singapore, Singapore
| | - Ines Ambite
- Division of Microbiology, Immunology and Glycobiology, Department of Laboratory Medicine, Faculty of Medicine, Lund University, Lund, Sweden
| | - K H Mok
- Trinity College Dublin, Trinity Biomedical Sciences Institute (TBSI), School of Biochemistry & Immunology, Dublin, Ireland
| | - Marek Babjuk
- Department of Urology, Motol University Hospital, Prague, Czech Republic.,2nd Faculty of Medicine, Charles University Praha, Prague, Czech Republic
| | - Catharina Svanborg
- Division of Microbiology, Immunology and Glycobiology, Department of Laboratory Medicine, Faculty of Medicine, Lund University, Lund, Sweden
| |
Collapse
|
5
|
Lin K, Mumtaz A, Rahaman MA, Mok KH. Social Quarantine and Its Four Modes: Conceptional Exploration and the Theoretical Construction of the Polices Against COVID-19. Front Public Health 2021; 9:614476. [PMID: 34631635 PMCID: PMC8495238 DOI: 10.3389/fpubh.2021.614476] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Accepted: 08/20/2021] [Indexed: 01/04/2023] Open
Abstract
Building on the studies of health quarantine from a social perspective, this article explores the complex contexts of social quarantine as a mode of public health, a mode of community action and a behavioural and psychological mode of social distancing. To establish a conceptual investigation of the "social quarantine" issue, this study investigates four approaches to quarantine: public health, social administration, behavioural norms, and psychological effects. The study identifies the features of these modes and discusses their relationships. In addition, this study constructs a preventive framework for quarantine that embraces social and health policies to enrich the understanding of policy measures for social distancing and lockdown measures. On this basis, the study evaluates the strategies of policy development in response to the COVID-19 pandemic. The study concludes that these modes can reconstruct social relations and provide some basis for theoretical analysis about the features of social quarantine, which is vital for policymakers when considering national and global prevention strategies for public health.
Collapse
Affiliation(s)
- Ka Lin
- College of Public Administration, Zhejiang University, Hangzhou, China
- Institute of Policy Studies, Lingnan University, Hong Kong SAR, China
| | - Ayesha Mumtaz
- College of Public Administration, Zhejiang University, Hangzhou, China
| | | | - Ka Ho Mok
- Institute of Policy Studies, Lingnan University, Hong Kong SAR, China
| |
Collapse
|
6
|
Ghanim M, Relitti N, McManus G, Butini S, Cappelli A, Campiani G, Mok KH, Kelly VP. A non-toxic, reversibly released imaging probe for oral cancer that is derived from natural compounds. Sci Rep 2021; 11:14069. [PMID: 34234213 PMCID: PMC8263592 DOI: 10.1038/s41598-021-93408-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Accepted: 06/24/2021] [Indexed: 02/06/2023] Open
Abstract
CD44 is emerging as an important receptor biomarker for various cancers. Amongst these is oral cancer, where surgical resection remains an essential mode of treatment. Unfortunately, surgery is frequently associated with permanent disfigurement, malnutrition, and functional comorbidities due to the difficultly of tumour removal. Optical imaging agents that can guide tumour tissue identification represent an attractive approach to minimising the impact of surgery. Here, we report the synthesis of a water-soluble fluorescent probe, namely HA-FA-HEG-OE (compound 1), that comprises components originating from natural sources: oleic acid, ferulic acid and hyaluronic acid. Compound 1 was found to be non-toxic, displayed aggregation induced emission and accumulated intracellularly in vesicles in SCC-9 oral squamous cells. The uptake of 1 was fully reversible over time. Internalization of compound 1 occurs through receptor mediated endocytosis; uniquely mediated through the CD44 receptor. Uptake is related to tumorigenic potential, with non-tumorigenic, dysplastic DOK cells and poorly tumorigenic MCF-7 cells showing only low intracellular levels and highlighting the critical role of endocytosis in cancer progression and metastasis. Together, the recognised importance of CD44 as a cancer stem cell marker in oral cancer, and the reversible, non-toxic nature of 1, makes it a promising agent for real time intraoperative imaging.
Collapse
Affiliation(s)
- Magda Ghanim
- School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin 2, Ireland
| | - Nicola Relitti
- Department of Biotechnology, Chemistry and Pharmacy, Department of Excellence 2018-2022, University of Siena, 53100, Siena, Italy
| | - Gavin McManus
- School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin 2, Ireland
| | - Stefania Butini
- Department of Biotechnology, Chemistry and Pharmacy, Department of Excellence 2018-2022, University of Siena, 53100, Siena, Italy.
| | - Andrea Cappelli
- Department of Biotechnology, Chemistry and Pharmacy, Department of Excellence 2018-2022, University of Siena, 53100, Siena, Italy
| | - Giuseppe Campiani
- Department of Biotechnology, Chemistry and Pharmacy, Department of Excellence 2018-2022, University of Siena, 53100, Siena, Italy
| | - K H Mok
- School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin 2, Ireland
| | - Vincent P Kelly
- School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin 2, Ireland.
| |
Collapse
|
7
|
Mok KH, Montgomery C. Remaking higher education for the post‐COVID‐19 era: Critical reflections on marketization, internationalization and graduate employment. Higher Education Quarterly 2021; 75:373-380. [PMCID: PMC8239816 DOI: 10.1111/hequ.12330] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Accepted: 04/06/2021] [Indexed: 06/18/2023]
Abstract
This Special Issue was conceived and developed following a series of international conferences held in Asia, with a particular focus on critically reflecting upon higher education development in the region from broader social and political economy perspectives. Some of the papers in this Special Issue were selected from presentations in the East Asia Social Policy (EASP) Research Network Conference successfully held in Taiwan in 2018, while others were chosen from international events held at Lingnan University in Hong Kong presenting critical reviews and reflections on internationalization, marketization and graduate employment of higher education in Asia. This introductory article puts the discussions of the selected papers in this issue in context, with critical reflections on the key issues being examined in these papers. The Special Issue is published when the world is still confronting the unprecedented global health crisis resulted from the outbreak of the COVID‐19 pandemic. This article discusses the higher education development trends in Asia through the massification, diversification and internationalisation processes in transforming the higher education system and examines how these development trends are affected by the COVID‐19 crisis.
Collapse
Affiliation(s)
- Ka Ho Mok
- Institute of Policy StudiesLingnan UniversityHong KongChina
| | | |
Collapse
|
8
|
Mok KH, Xiong W, Ke G, Cheung JOW. Impact of COVID-19 pandemic on international higher education and student mobility: Student perspectives from mainland China and Hong Kong. Int J Educ Res 2021; 105:101718. [PMID: 35719275 PMCID: PMC9188844 DOI: 10.1016/j.ijer.2020.101718] [Citation(s) in RCA: 62] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Revised: 10/26/2020] [Accepted: 11/21/2020] [Indexed: 05/06/2023]
Abstract
The study critically examines how students in Mainland China and Hong Kong conceive overseas studies plans against the COVID-19 crisis. Amongst the 2739 respondents, 84 % showed no interest to study abroad after the pandemic. For those respondents who will continue to pursue further degrees abroad, Asian regions and countries, specifically Hong Kong, Japan and Taiwan, are listed in the top five, apart from the US and the UK. The pandemic has not only significantly decreased international student mobility but is also shifting the mobility flow of international students. This article also discusses the policy implications, particularly reflecting on how the current global health crisis would intensify social and economic inequalities across different higher education systems.
Collapse
Affiliation(s)
- Ka Ho Mok
- Institute of Policy Studies, Lingnan University, Hong Kong, China
| | - Weiyan Xiong
- Institute of Policy Studies, Lingnan University, Hong Kong, China
| | - Guoguo Ke
- Institute of Policy Studies, Lingnan University, Hong Kong, China
| | | |
Collapse
|
9
|
Abstract
Diffusion-ordered spectroscopy (DOSY) is a widely used NMR technique for the identification of different chemical moieties/compounds contained in mixtures and has been successfully employed for the separation of small molecules based on hydrodynamic radii. Herein we show that DOSY can also be applied for the size determination of larger biomolecules such as proteins and protein oligomers/aggregates. Proof-of-principle is first shown with a cross-linked oligomeric protein mixture where the hydrodynamic volumes of each component are estimated and subsequently verified with size-exclusion HPLC and SDS polyacrylamide gel electrophoresis. We then determine the sizes of protein oligomers contained in a protein solution subjected under amyloid fibrillogenesis conditions. These studies aim to provide insight into the kinetics behind protein aggregation involved in amyloidosis as well as to determine the hydrodynamic radii of proteins within the mixture.
Collapse
Affiliation(s)
- Pancham S Kandiyal
- Trinity Biomedical Sciences Institute (TBSI), School of Biochemistry & Immunology, Trinity College Dublin, Dublin, Ireland
| | - Ji Yoon Kim
- Trinity Biomedical Sciences Institute (TBSI), School of Biochemistry & Immunology, Trinity College Dublin, Dublin, Ireland
| | - Daniel L Fortunati
- Trinity Biomedical Sciences Institute (TBSI), School of Biochemistry & Immunology, Trinity College Dublin, Dublin, Ireland
| | - K H Mok
- Trinity Biomedical Sciences Institute (TBSI), School of Biochemistry & Immunology, Trinity College Dublin, Dublin, Ireland.
| |
Collapse
|
10
|
Mok KH, Wickramarachchi U, Watson T, Ho HH, Eccleshall S, Ong PJL. Avoid stent insertion in drug-coated balloon angioplasty. Herz 2017; 42:698. [PMID: 28168429 DOI: 10.1007/s00059-017-4543-8] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- K H Mok
- Department of Cardiology, Tan Tock Seng, Hospital, , 11 Jalan Tan Tock Seng, 308433, Singapore, Singapore
| | - U Wickramarachchi
- Department of Cardiology, Norwich and Norfolk University Hospital, Norwich, UK
| | - T Watson
- Department of Cardiology, Tan Tock Seng, Hospital, , 11 Jalan Tan Tock Seng, 308433, Singapore, Singapore.
- Faculty of Medicine and Health Science, University of Auckland, Auckland, New Zealand.
| | - H H Ho
- Department of Cardiology, Tan Tock Seng, Hospital, , 11 Jalan Tan Tock Seng, 308433, Singapore, Singapore
| | - S Eccleshall
- Department of Cardiology, Norwich and Norfolk University Hospital, Norwich, UK
| | - P J L Ong
- Department of Cardiology, Tan Tock Seng, Hospital, , 11 Jalan Tan Tock Seng, 308433, Singapore, Singapore
| |
Collapse
|
11
|
Ho JCS, Storm P, Rydström A, Bowen B, Alsin F, Sullivan L, Ambite I, Mok KH, Northen T, Svanborg C. Lipids as tumoricidal components of human α-lactalbumin made lethal to tumor cells (HAMLET): unique and shared effects on signaling and death. J Biol Chem 2013; 288:17460-71. [PMID: 23629662 DOI: 10.1074/jbc.m113.468405] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [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: 12/21/2022] Open
Abstract
Long-chain fatty acids are internalized by receptor-mediated mechanisms or receptor-independent diffusion across cytoplasmic membranes and are utilized as nutrients, building blocks, and signaling intermediates. Here we describe how the association of long-chain fatty acids to a partially unfolded, extracellular protein can alter the presentation to target cells and cellular effects. HAMLET (human α-lactalbumin made lethal to tumor cells) is a tumoricidal complex of partially unfolded α-lactalbumin and oleic acid (OA). As OA lacks independent tumoricidal activity at concentrations equimolar to HAMLET, the contribution of the lipid has been debated. We show by natural abundance (13)C NMR that the lipid in HAMLET is deprotonated and by chromatography that oleate rather than oleic acid is the relevant HAMLET constituent. Compared with HAMLET, oleate (175 μm) showed weak effects on ion fluxes and gene expression. Unlike HAMLET, which causes metabolic paralysis, fatty acid metabolites were less strongly altered. The functional overlap increased with higher oleate concentrations (500 μm). Cellular responses to OA were weak or absent, suggesting that deprotonation favors cellular interactions of fatty acids. Fatty acids may thus exert some of their essential effects on host cells when in the deprotonated state and when presented in the context of a partially unfolded protein.
Collapse
Affiliation(s)
- James C S Ho
- Department of Microbiology, Immunology, and Glycobiology (MIG), Institute of Laboratory Medicine, Lund University, Sölvegatan 23, S-223 62 Lund, Sweden
| | | | | | | | | | | | | | | | | | | |
Collapse
|
12
|
Rehman S, Ikram M, Baker RJ, Zubair M, Azad E, Min S, Riaz K, Mok KH, Rehman SU. Synthesis, characterization, in vitro antimicrobial, and U2OS tumoricidal activities of different coumarin derivatives. Chem Cent J 2013; 7:68. [PMID: 23587363 PMCID: PMC3668295 DOI: 10.1186/1752-153x-7-68] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2013] [Accepted: 03/19/2013] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Coumarin and its derivatives are biologically very active. It was found that the enhanced activities are dependent on the coumarin nucleus. Biological significance of these compounds include anti-bacterial, anti-thrombotic and vasodilatory, anti-mutagenic, lipoxygenase and cyclooxygenase inhibition, scavenging of reactive oxygen species, and anti-tumourigenic. Our interest in medicinal chemistry of dicoumarol compounds have been developed by keeping in view the importance of coumarins along with its derivatives in medicinal chemistry. All the synthesized compounds were fully characterized by spectroscopic and analytical techniques and were screened for antimicrobial and U2OS bone cancer activities. RESULTS 4-hydroxycoumarin was derivatized by condensing with different aldehydes yielding the dicoumarol and translactonized products. Elemental analyses, ESI(+,-) MS, 1H and 13C{1H}-NMR, infrared spectroscopy and conductance studies were used to characterize the synthesized compounds which revealed the dicoumarol and dichromone structures for the compounds. The compounds were screened against U2OS cancerous cells and pathogenic micro organisms. The compounds with intermolecular H-bonding were found more active revealing a possible relationship among hydrogen bonding, cytotoxicity and antimicrobial activities. CONCLUSION Coumarin based drugs can be designed for the possible treatment of U2OS leukemia.
Collapse
Affiliation(s)
- Sadia Rehman
- Institute of Chemical Sciences, University of Peshawar 25120, Peshawar, Pakistan
- Department of Chemistry, Sarhad University of Science and Information Technology, Peshawar, Pakistan
| | - Muhammad Ikram
- Department of Chemistry, Sarhad University of Science and Information Technology, Peshawar, Pakistan
| | - Robert J Baker
- School of Chemistry, University of Dublin, Trinity College Dublin 2, Dublin, Ireland
| | - Muhammad Zubair
- School of Chemistry, University of Dublin, Trinity College Dublin 2, Dublin, Ireland
| | - Effat Azad
- Trinity Biomedical Sciences Institute (TBSI), School of Biochemistry and Immunology, Trinity College Dublin, Dublin 2, Ireland
| | - Soyoung Min
- Trinity Biomedical Sciences Institute (TBSI), School of Biochemistry and Immunology, Trinity College Dublin, Dublin 2, Ireland
| | - Kashif Riaz
- Department of Plant Pathology, University of Agriculture Faisalabad-Pakistan, Faisalabad, Pakistan
| | - KH Mok
- Trinity Biomedical Sciences Institute (TBSI), School of Biochemistry and Immunology, Trinity College Dublin, Dublin 2, Ireland
| | - Saeed-Ur Rehman
- Institute of Chemical Sciences, University of Peshawar 25120, Peshawar, Pakistan
| |
Collapse
|
13
|
Abstract
OBJECTIVE The major objective of this article is to critically examine changes in social stratification and social mobility of the peasant workers in the post-Mao period, with particular reference to examine whether and how the selected peasant workers in Dongguan city in South China have asserted themselves in protecting their labour rights. METHODS The present studies is based upon intensive policy and documentary analysis, in-depth interviews, focus group discussions and survey in getting first-hand data from conducting fieldwork in China. PARTICIPANTS Migrant workers in Dongguan city in South China. RESULTS Although peasant workers are becoming more concerned with their economic and social rights, they have not attempted to organize themselves as organized social organizations in protecting their own interests. Despite the fact that peasant workers may have a greater awareness of the interests as a social group, such a consciousness has not been developed into a distinct class identity. CONCLUSIONS Without a distinct class identity, coupled with a lack of organized social forces in asserting their class interests, peasant workers have not formed themselves into an organized social class right now, especially as many of them still consider themselves having a peasant status instead of obtaining a new citizenship associated with working in urban China.
Collapse
Affiliation(s)
- Ka Ho Mok
- Faculty of Arts and Sciences, The Hong Kong Institute of Education, Hong Kong, China.
| | | |
Collapse
|
14
|
Gattin Z, Riniker S, Hore PJ, Mok KH, van Gunsteren WF. Temperature and urea induced denaturation of the TRP-cage mini protein TC5b: A simulation study consistent with experimental observations. Protein Sci 2009; 18:2090-9. [PMID: 19693803 PMCID: PMC2786973 DOI: 10.1002/pro.223] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2009] [Revised: 06/27/2009] [Accepted: 07/29/2009] [Indexed: 11/09/2022]
Abstract
The effects of temperature and urea denaturation (6M urea) on the dominant structures of the 20-residue Trp-cage mini-protein TC5b are investigated by molecular dynamics simulations of the protein at different temperatures in aqueous and in 6M urea solution using explicit solvent degrees of freedom and the GROMOS force-field parameter set 45A3. In aqueous solution at 278 K, TC5b is stable throughout the 20 ns of MD simulation and the trajectory structures largely agree with the NMR-NOE atom-atom distance data available. Raising the temperature to 360 K and to 400 K, the protein denatures within 22 ns and 3 ns, showing that the denaturation temperature is well below 360 K using the GROMOS force field. This is 40-90 K lower than the denaturation temperatures observed in simulations using other much used protein force fields. As the experimental denaturation temperature is about 315 K, the GROMOS force field appears not to overstabilize TC5b, as other force fields and the use of continuum solvation models seem to do. This feature may directly stem from the GROMOS force-field parameter calibration protocol, which primarily involves reproduction of condensed phase thermodynamic quantities such as energies, densities, and solvation free energies of small compounds representative for protein fragments. By adding 6M urea to the solution, the onset of denaturation is observed in the simulation, but is too slow to observe a particular side-chain side-chain contact (Trp6-Ile4) that was experimentally observed to be characteristic for the denatured state. Interestingly, using temperature denaturation, the process is accelerated and the experimental data are reproduced.
Collapse
Affiliation(s)
- Z Gattin
- Laboratory of Physical Chemistry, Swiss Federal Institute of TechnologyETH, Zürich 8093, Switzerland
| | - S Riniker
- Laboratory of Physical Chemistry, Swiss Federal Institute of TechnologyETH, Zürich 8093, Switzerland
| | - P J Hore
- Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of OxfordOxford OX1 3QZ, United Kingdom
| | - K H Mok
- School of Biochemistry and Immunology, Trinity College Dublin, College GreenDublin 2, Ireland
| | - W F van Gunsteren
- Laboratory of Physical Chemistry, Swiss Federal Institute of TechnologyETH, Zürich 8093, Switzerland
| |
Collapse
|
15
|
|
16
|
Abstract
PurposeThe article aims to offer an introduction to the special issue on changing education governance in Asia.Design/methodology/approachA brief overview of the issue is provided.FindingsThe article notes that one of the prominent issues running through the issue is the dilemma between the assertion of academic freedom and the deepening governance/management reforms in schools and universities.Originality/valueThe article highlights that the issue offers a distinct comparative perspective in analyzing recent changes in education governance and management in selected Asian societies.
Collapse
|
17
|
|
18
|
Abstract
PURPOSE To test the relationship between the results of short-wavelength automatic perimetry (SWAP) and retinal nerve fiber layer (RNFL) measurements with scanning laser polarimetry (Nerve Fiber Analyzer, NFA) in age-matched normal subjects, glaucoma suspects, and early glaucoma patients. DESIGN Case-control study. PARTICIPANTS AND METHODS Thirty-eight normal subjects, 32 glaucoma suspects, and 14 early glaucoma patients were recruited. All subjects underwent RNFL assessment by NFA, achromatic visual field testing (24-2 threshold), and repeated SWAP (24-2 threshold blue-on-yellow). MAIN OUTCOME MEASURES Mean deviation (MD) of visual field testing and RNFL values were obtained. RESULTS Glaucoma suspects were divided into two groups according to their SWAP results: high risk (with SWAP abnormalities) and low risk (with normal SWAP result). No statistically significant difference in SWAP MD and RNFL values were observed between normal and low-risk groups (P > 0.05), but these values were found to be significantly lower in high-risk and early glaucoma groups (P < 0.01). CONCLUSIONS This study suggests that RNFL examination by NFA may be a useful test for the early detection of glaucomatous damage of glaucoma suspects. It appears to provide agreement with SWAP abnormalities and is more sensitive than conventional standard automated perimetry.
Collapse
Affiliation(s)
- K H Mok
- Eye Centre, Hong Kong Adventist Hospital, Hong Kong, People's Republic of China
| | | |
Collapse
|
19
|
Lee H, Mok KH, Muhandiram R, Park KH, Suk JE, Kim DH, Chang J, Sung YC, Choi KY, Han KH. Local structural elements in the mostly unstructured transcriptional activation domain of human p53. J Biol Chem 2000; 275:29426-32. [PMID: 10884388 DOI: 10.1074/jbc.m003107200] [Citation(s) in RCA: 274] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
DNA transcription is initiated by a small regulatory region of transactivators known as the transactivation domain. In contrast to the rapid progress made on the functional aspect of this promiscuous domain, its structural feature is still poorly characterized. Here, our multidimensional NMR study reveals that an unbound full-length p53 transactivation domain, although similar to the recently discovered group of loosely folded proteins in that it does not have tertiary structure, is nevertheless populated by an amphipathic helix and two nascent turns. The helix is formed by residues Thr(18)-Leu(26) (Thr-Phe-Ser-Asp-Leu-Trp-Lys-Leu-Leu), whereas the two turns are formed by residues Met(40)-Met(44) and Asp(48)-Trp(53), respectively. It is remarkable that these local secondary structures are selectively formed by functionally critical and positionally conserved hydrophobic residues present in several acidic transactivation domains. This observation suggests that such local structures are general features of acidic transactivation domains and may represent "specificity determinants" (Ptashne, M., and Gann, A. A. F. (1997), Nature 386, 569-577) that are important for transcriptional activity.
Collapse
Affiliation(s)
- H Lee
- Protein Engineering Laboratory, Korea Research Institute of Bioscience and Biotechnology, Yusong, P. O. Box 115, Taejon 305-600, South Korea
| | | | | | | | | | | | | | | | | | | |
Collapse
|
20
|
Abstract
PURPOSE To obtain normal retinal nerve fibre layer (RNFL) measurements by scanning laser polarimetry in a local Hong Kong Chinese population and to identify the correlation of the measurements with age. METHODS One hundred and fifty-nine normal Hong Kong Chinese volunteers of different ages were recruited for this study. RNFL values were measured using a Nerve Fibre Analyzer GDx (Laser Diagnostic Technologies, CA). RESULTS Mean peripapillary RNFL measurements at the superior, inferior, temporal and nasal regions were 95.0 +/- 15.6, 97.0 +/- 16.3, 47.0 +/- 9.0 and 43.9 +/- 15.1 microns respectively (mean +/- SD). There was a highly significant negative correlation in average RNFL values with increasing age (approximately 1.9 microns per decade, p = 0.001). A significant negative correlation with increasing age was also identified in the RNFL values in all four regions and they decreased by similar amounts (p < 0.05). No correlation with age was observed for relative ratio parameters such as superior/nasal ratio, inferior/nasal ratio and max. modulation (p > 0.05). CONCLUSION RNFL values of the Hong Kong Chinese population appeared to decrease over time cross-sectionally. Since they decreased by similar amounts at four regions, use of relative ratio parameters for analysis has an advantage over absolute values, as they were not affected by age.
Collapse
Affiliation(s)
- V W Lee
- Hong Kong Adventist Hospital, Department of Anatomy, Hong Kong University, Hong Kong.
| | | |
Collapse
|
21
|
Mok KH. Tono-Pen tonometer and corneal thickness. Eye (Lond) 2000; 14 ( Pt 3A):410. [PMID: 11027020 DOI: 10.1038/eye.2000.108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
|
22
|
Abstract
PURPOSE To compare the intraocular pressure (IOP) measurements taken at the central cornea with those taken at the mid-peripheral cornea using the Tono-Pen tonometer. METHODS Forty-eight normal human subjects had their IOP measurements taken (i) with the Goldmann tonometer, (ii) with the Tono-Pen at the central cornea and (iii) with the Tono-Pen at the mid-peripheral cornea. The central and mid-peripheral corneal thickness at the site of IOP measurements were then determined by ultrasonic pachymetry. RESULTS The mean IOP with the Goldmann tonometer was 15.7 +/- 3.1 mmHg. The mean Tono-Pen IOPs at the central and midperipheral cornea were 15.2 +/- 3.2 mmHg and 15.7 +/- 3.3 mmHg respectively. The mean midperipheral corneal thickness (578 microns) was significantly higher than the mean central thickness (538 microns) (p < 0.001). CONCLUSION There was no significant difference between the IOP taken with the Tono-Pen and with the Goldmann tonometer. In addition, no clinically significant difference was observed between the IOP readings of central and mid-peripheral cornea measured by the Tono-Pen.
Collapse
Affiliation(s)
- K H Mok
- Queen Mary Hospital Unit, Department of Ophthalmology and Visual Sciences, Chinese University of Hong Kong, China.
| | | | | |
Collapse
|
23
|
Cho JH, Mok KH, Olivera BM, McIntosh JM, Park KH, Han KH. Nuclear magnetic resonance solution conformation of alpha-conotoxin AuIB, an alpha(3)beta(4) subtype-selective neuronal nicotinic acetylcholine receptor antagonist. J Biol Chem 2000; 275:8680-5. [PMID: 10722709 DOI: 10.1074/jbc.275.12.8680] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The neuronal nicotinic acetylcholine receptors constitute a highly diverse group, with subtypes consisting of pentameric combinations of alpha and beta subunits. alpha-Conotoxins are a homologous series of small peptides that antagonize these receptors. We present the three-dimensional solution structure of alpha-conotoxin AuIB, the first 15-residue alpha-conotoxin known to selectively block the alpha(3)beta(4) nicotinic acetylcholine receptor subtype. The pairwise backbone and heavy-atom root mean square deviation for an ensemble of 20 structures are 0.269 and 0.720 A, respectively. The overall fold of alpha-conotoxin AuIB closely resembles that of the alpha4/7 subfamily alpha-conotoxins. However, the absence of Tyr(15), normally present in other alpha4/7 members, results in tight bending of the backbone at the C terminus and effectively renders Asp(14) to assume the spatial location of Tyr(15) present in other neuronal alpha4/7 alpha-conotoxins. Structural comparison of alpha-conotoxin AuIB with the alpha(3)beta(2) subtype-specific alpha-conotoxin MII shows different electrostatic surface charge distributions, which may be important in differential receptor subtype recognition.
Collapse
Affiliation(s)
- J H Cho
- Protein Engineering Laboratory, Korea Research Institute of Bioscience and Biotechnology, Yusong, Taejon 305-600, Republic of Korea
| | | | | | | | | | | |
Collapse
|
24
|
Mok KH, Han KH. NMR solution conformation of an antitoxic analogue of alpha-conotoxin GI: identification of a common nicotinic acetylcholine receptor alpha 1-subunit binding surface for small ligands and alpha-conotoxins. Biochemistry 1999; 38:11895-904. [PMID: 10508392 DOI: 10.1021/bi990558n] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The three-dimensional solution conformation of an 11-residue antitoxic analogue of alpha-conotoxin GI, des-Glu1-[Cys3Ala]-des-Cys13-conotoxin GI (CANPACGRHYS-NH(2), designated "GI-15" henceforth), has been determined using two-dimensional (1)H NMR spectroscopy. The disulfide loop region (1C-6C) and the C-terminal tail (8R-11S) are connected by a flexible hinge formed near 7G, and the pairwise backbone rmsds for the former and the latter are 0.58 and 0.65 A, respectively. Superpositioning GI-15 with the structure of alpha-conotoxin GI shows that the two share an essentially identical fold in the common first disulfide loop region (1C-6C). However, the absence of the second disulfide loop in GI-15 results in segmental motion of the C-terminal half, causing the key receptor subtype selectivity residue 8R (Arg9 in alpha-conotoxin GI) to lose its native spatial orientation. The combined features of structural equivalence in the disulfide loop and a mobile C-terminal tail appear to be responsible for the activity of GI-15 as a competitive antagonist against native toxin. Electrostatic surface potential comparisons of the first disulfide region of GI-15 with other alpha-conotoxins or receptor-bound states of acetylcholine and d-tubocurarine show a common protruding surface that may serve as the minimal binding determinant for the neuromuscular acetylcholine receptor alpha 1-subunit. On the basis of the original "Conus toxin macrosite model" [Olivera, B. M., Rivier, J., Scott, J. K., Hillyard, D. R., and Cruz, L. J. (1991) J. Biol. Chem. 266, 1923-1936], we propose a revised binding model which incorporates these results.
Collapse
Affiliation(s)
- K H Mok
- Biomolecular Structure Research Unit, Korea Research Institute of Bioscience and Biotechnology, Taejon, Republic of Korea
| | | |
Collapse
|
25
|
Abstract
OBJECTIVE To identify the pattern of retinal nerve fiber layer (RNFL) loss in glaucoma using the Nerve Fiber Analyzer (NFA). DESIGN Case-control study. PARTICIPANTS A total of 80 normal and 75 age- and race-matched chronic open-angle glaucoma subjects were recruited. INTERVENTION The RNFL thickness was assessed with a scanning laser polarimeter (Nerve Fiber Analyzer GDX, Laser Diagnostic Technologies Inc., San Diego, CA). Analysis of variance was used to compare the corresponding RNFL measurement indices of the different groups. MAIN OUTCOME MEASURES Superior/nasal (S/N) and inferior/nasal (I/N) ratios of NFA are sensitive parameters to differentiate between glaucoma and nonglaucoma subjects. RESULTS Peripapillary RNFL measurements at the superior and inferior regions were significantly lower in the glaucoma group (P<0.001) but were similar in temporal and nasal regions (P>0.05). Using nasal value as reference, S/N and I/N ratios were significantly lower in the glaucoma groups (P<0.001) and also decreased with increasing severity of glaucoma. CONCLUSIONS In glaucoma, RNFL was more susceptible to loss in the superior and inferior regions than in the nasal and temporal regions. The S/N and I/N ratio parameters provided by the NFA appeared to give further discriminating ability in early glaucoma.
Collapse
Affiliation(s)
- V W Lee
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong
| | | |
Collapse
|
26
|
Abstract
The introduction of the DigiGraph Workstation permits the use of sonic digitization to measure lateral cephalometric values, mesiodistal tooth size and arch perimeter discrepancy as a one-stop diagnostic record taking set-up. This study compared the reproducibility of mesiodistal total tooth widths and arch perimeter values, on plaster casts, given by the DigiGraph Workstation and by digital calipers. Forty-seven sets of plaster casts of Southern Chinese children (mean age 12.5 years) comprised the sample. Arch perimeter was measured using calipers in six segments from the distal of the first permanent molar to its antimere in each arch. The total mesiodistal widths of all teeth, excluding second and third molars, were also measured. The difference between the available arch perimeter and the total tooth widths was taken as the arch perimeter discrepancy. Sonic digitization of the study casts was completed according to instructions of the DigiGraph software. Paired t-tests and F-tests were used to compare the two methods. Compared with manual measurement, there was an over-estimation of the total tooth widths by 1 mm in the mandible and 0.5 mm in the maxilla, and an arch perimeter discrepancy of 1.6 mm in the mandible and 0.4 mm in the maxilla when using the sonic method. The sonic digitization was not as reproducible as the digital caliper and its clinical usefulness in evaluating the space problem of an individual malocclusion should be interpreted with caution.
Collapse
Affiliation(s)
- K H Mok
- University of Hong Kong, Hong Kong
| | | |
Collapse
|
27
|
To CH, Mok KH, Tse SK, Siu WT, Millodot M, Lee KL, Hodson S. In vitro bovine ciliary body/epithelium in a small continuously perfused Ussing type chamber. Cell Struct Funct 1998; 23:247-54. [PMID: 9872565 DOI: 10.1247/csf.23.247] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Our goal is to assess the viability of an in vitro preparation of bovine ciliary body/epithelium (CBE) in a small volume Ussing-type chamber. A new small volume Ussing-type chamber with continuous perfusion was developed for bovine CBE. The trans-CBE electrical parameters were monitored and the electrical responses of the CBE to ouabain (1 and 0.01 mM) were recorded. The trans-CBE fluxes of [14C]-L-ascorbate and [3H]-L-glucose were also studied. The bovine CBE preparation was stable inside the chamber in terms of its potential difference (PD), short circuit current (SCC) and trans-CBE resistance. They were -0.51+/-0.05 mV (aqueous side negative), -5.43+/-0.04 microAcm-2 and 94+/-2 Q.cm2 (mean s.e.m., n=35), respectively. The preparation hyperpolarised when 0.01 mM ouabain was administered to the aqueous side, depolarised when ouabain was applied to the stromal side. [3H]-L-glucose diffusion was about 74 nEq h(-1)cm(-2) in either direction (n=12). Taking the area magnification factor of the CBE into consideration, the diffusional L-glucose flux across the bovine CBE was comparable to other tight epithelia. A significant net ascorbate flux (0.26+/-0.05 nEq h(-1)cm(-2), n=4, p<0.01) was found in the stroma to aqueous direction. We have developed a viable in vitro bovine CBE preparation which was (1) electrically stable, (2) responsive to ouabain, (3) tight to L-glucose diffusion, and (4) capable of actively secreting ascorbate. A net trans-CBE chloride transport (0.81+/-0.30 microEq h(-1)cm(-2), n=12, p=0.01) from stromal to aqueous side was found in the present in vitro model under short-circuited conditions.
Collapse
Affiliation(s)
- C H To
- The Department of Optometry and Radiography, The Hong Kong Polytechnic University, Hung Hom.
| | | | | | | | | | | | | |
Collapse
|
28
|
Abstract
PURPOSE To study the chloride and sodium ion transports across the bovine ciliary body/epithelium (CBE) by a modified Ussing-Zerahn type chamber. METHODS Isolated bovine CBE preparations were mounted in a modified Ussing-type chamber and the transepithelial electrical parameters were monitored. The inward (stroma to aqueous) and outward (aqueous to stroma) fluxes of 36[Cl] chloride and 22[Na] sodium ions across the CBE were measured under short-circuited conditions. The effect of 0.1 mM of furosemide and bumetanide on the chloride transport were studied. RESULTS The potential difference (PD), the resistance and the short-circuit current (SCC) across the isolated bovine ciliary body were found to be -0.20+/-0.01 mV (aqueous negative), 75+/-1 omegacm2 and -2.70+/-0.17 microAcm(-2) (mean+/-SEM, n=50) respectively. A statistically significant net inward chloride ion flux of 1.12+/-0.41 microEq h(-1)cm(-2) (p < 0.01) was found (n=15). The net chloride transport was abolished when 0.1 mM furosemide (82% inhibition) and 0.1 mM bumetanide (100% inhibition) were applied bilateral. No significant net sodium ion flux was detected. CONCLUSIONS Electrolyte and fluid transport across the bovine CBE may be via a bumetanide and furosemide-sensitive chloride transport mechanism. The Na-K-2Cl cotransporter plays a significant role in the trans-CBE chloride transport. The net chloride flux/current was about 12 times higher than the measured SCC, suggesting that the chloride ion transport may be coupled to other ion species.
Collapse
Affiliation(s)
- C H To
- Department of Optometry and Radiography, The Hong Kong Polytechnic University, China
| | | | | | | | | |
Collapse
|