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Neidemire-Colley L, Khanal S, Braunreiter KM, Gao Y, Kumar R, Snyder KJ, Weber MA, Surana S, Toirov O, Karunasiri M, Duszynski ME, Chi M, Malik P, Kalyan S, Chan WK, Naeimi Kararoudi M, Choe HK, Garzon R, Ranganathan P. CRISPR/Cas9 deletion of MIR155HG in human T cells reduces incidence and severity of acute GVHD in a xenogeneic model. Blood Adv 2024; 8:947-958. [PMID: 38181781 PMCID: PMC10877121 DOI: 10.1182/bloodadvances.2023010570] [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] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Revised: 12/19/2023] [Accepted: 12/19/2023] [Indexed: 01/07/2024] Open
Abstract
ABSTRACT Acute graft-versus-host disease (GVHD) is a major complication of allogeneic hematopoietic cell transplantation (allo-HCT). Using preclinical mouse models of disease, previous work in our laboratory has linked microRNA-155 (miR-155) to the development of acute GVHD. Transplantation of donor T cells from miR-155 host gene (MIR155HG) knockout mice prevented acute GVHD in multiple murine models of disease while maintaining critical graft-versus-leukemia (GVL) response, necessary for relapse prevention. In this study, we used clustered, regularly interspaced, short palindromic repeats (CRISPR)/Cas9 genome editing to delete miR-155 in primary T cells (MIR155HGΔexon3) from human donors, resulting in stable and sustained reduction in expression of miR-155. Using the xenogeneic model of acute GVHD, we show that NOD/SCID/IL2rγnull (NSG) mice receiving MIR155HGΔexon3 human T cells provide protection from lethal acute GVHD compared with mice that received human T cells with intact miR-155. MIR155HGΔexon3 human T cells persist in the recipients displaying decreased proliferation potential, reduced pathogenic T helper-1 cell population, and infiltration into GVHD target organs, such as the liver and skin. Importantly, MIR155HGΔexon3 human T cells retain GVL response significantly improving survival in an in vivo model of xeno-GVL. Altogether, we show that CRISPR/Cas9-mediated deletion of MIR155HG in primary human donor T cells is an innovative approach to generate allogeneic donor T cells that provide protection from lethal GVHD while maintaining robust antileukemic response.
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Affiliation(s)
- Lotus Neidemire-Colley
- Division of Hematology, Department of Internal Medicine, The Ohio State University, Columbus, OH
- Biological Sciences Graduate Program, The Ohio State University, Columbus, OH
| | - Shrijan Khanal
- Division of Hematology, Department of Internal Medicine, The Ohio State University, Columbus, OH
- Molecular, Cellular and Developmental Biology Graduate Program, The Ohio State University, Columbus, OH
| | - Kara M. Braunreiter
- Division of Hematology, Department of Internal Medicine, The Ohio State University, Columbus, OH
- Pelotonia Institute for Immuno-Oncology, The Ohio State University Comprehensive Cancer Center, Columbus, OH
| | - Yandi Gao
- Division of Hematology, Department of Internal Medicine, The Ohio State University, Columbus, OH
- Pelotonia Institute for Immuno-Oncology, The Ohio State University Comprehensive Cancer Center, Columbus, OH
| | - Rathan Kumar
- Division of Hematology, Department of Internal Medicine, The Ohio State University, Columbus, OH
- Biological Sciences Graduate Program, The Ohio State University, Columbus, OH
| | - Katiri J. Snyder
- Division of Hematology, Department of Internal Medicine, The Ohio State University, Columbus, OH
- Biological Sciences Graduate Program, The Ohio State University, Columbus, OH
| | - Margot A. Weber
- Division of Hematology, Department of Internal Medicine, The Ohio State University, Columbus, OH
| | - Simran Surana
- Division of Hematology, Department of Internal Medicine, The Ohio State University, Columbus, OH
| | - Olimjon Toirov
- Division of Hematology, Department of Internal Medicine, The Ohio State University, Columbus, OH
| | - Malith Karunasiri
- Division of Hematology, Department of Internal Medicine, The Ohio State University, Columbus, OH
| | - Molly E. Duszynski
- Division of Experimental Hematology and Cancer Biology, Cancer and Blood Disease Institute, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH
| | - Mengna Chi
- Division of Experimental Hematology and Cancer Biology, Cancer and Blood Disease Institute, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH
| | - Punam Malik
- Division of Experimental Hematology and Cancer Biology, Cancer and Blood Disease Institute, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH
| | - Sonu Kalyan
- Department of Pathology, New York University Langone Health, Long Island, NY
| | - Wing K. Chan
- Division of Hematology, Department of Internal Medicine, The Ohio State University, Columbus, OH
| | - Meisam Naeimi Kararoudi
- Center for Childhood Cancer and Blood Diseases, Abigail Wexner Research Institute at Nationwide Children’s Hospital, Columbus, OH
- Department of Pediatrics, The Ohio State University, Columbus, OH
| | - Hannah K. Choe
- Division of Hematology, Department of Internal Medicine, The Ohio State University, Columbus, OH
- Pelotonia Institute for Immuno-Oncology, The Ohio State University Comprehensive Cancer Center, Columbus, OH
| | - Ramiro Garzon
- Division of Hematology and Hematological Malignancies, Huntsman Cancer Institute, The University of Utah, Salt Lake City, UT
| | - Parvathi Ranganathan
- Division of Hematology, Department of Internal Medicine, The Ohio State University, Columbus, OH
- Pelotonia Institute for Immuno-Oncology, The Ohio State University Comprehensive Cancer Center, Columbus, OH
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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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Hanel W, Shindiapina P, Bond DA, Sawalha Y, Epperla N, Voorhees T, Welkie RL, Huang Y, Behbehani GK, Zhang X, McLaughlin E, Chan WK, Brammer JE, Jaglowski S, Reneau JC, Christian BA, William BM, Cohen JB, Baiocchi RA, Maddocks K, Blum KA, Alinari L. A Phase 2 Trial of Ibrutinib and Nivolumab in Patients with Relapsed or Refractory Classical Hodgkin's Lymphoma. Cancers (Basel) 2023; 15:1437. [PMID: 36900230 PMCID: PMC10000669 DOI: 10.3390/cancers15051437] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Revised: 02/15/2023] [Accepted: 02/22/2023] [Indexed: 03/12/2023] Open
Abstract
BACKGROUND Relapsed or refractory classical Hodgkin lymphoma (cHL) remains a difficult treatment challenge. Although checkpoint inhibitors (CPI) have provided clinical benefit for these patients, responses are generally not durable, and progression eventually occurs. Discovering combination therapies which maximize the immune response of CPI therapy may overcome this limitation. We hypothesized that adding ibrutinib to nivolumab will lead to deeper and more durable responses in cHL by promoting a more favorable immune microenvironment leading to enhanced T-cell-mediated anti-lymphoma responses. METHODS We conducted a single arm, phase II clinical trial testing the efficacy of nivolumab in combination with ibrutinib in patients ≥18 years of age with histologically confirmed cHL who had received at least one prior line of therapy. Prior treatment with CPIs was allowed. Ibrutinib was administered at 560 mg daily until progression in combination with nivolumab 3 mg/kg IV every 3 weeks for up to 16 cycles. The primary objective was complete response rate (CRR) assessed per Lugano criteria. Secondary objectives included overall response rate (ORR), safety, progression free survival (PFS), and duration of response (DoR). RESULTS A total of 17 patients from two academic centers were enrolled. The median age of all patients was 40 (range 20-84). The median number of prior lines of treatment was five (range 1-8), including 10 patients (58.8%) who had progressed on prior nivolumab therapy. Most treatment related events were mild ( CONCLUSIONS Combined nivolumab and ibrutinib led to a CRR of 29.4% in R/R cHL. Although this study did not meet its primary efficacy endpoint of a CRR of 50%, likely due to enrollment of heavily pretreated patients including over half of who had progressed on prior nivolumab treatment, responses that were achieved with combination ibrutinib and nivolumab therapy tended to be durable even in the case of prior progression on nivolumab therapy. Larger studies investigating the efficacy of dual BTK inhibitor/immune checkpoint blockade, particularly in patients who had previously progressed on checkpoint blockade therapy, are warranted.
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Affiliation(s)
- Walter Hanel
- Division of Hematology, Department of Medicine, The Ohio State University, 460 W 10th Ave., Columbus, OH 43210, USA
| | - Polina Shindiapina
- Division of Hematology, Department of Medicine, The Ohio State University, 460 W 10th Ave., Columbus, OH 43210, USA
| | - David A. Bond
- Division of Hematology, Department of Medicine, The Ohio State University, 460 W 10th Ave., Columbus, OH 43210, USA
| | - Yazeed Sawalha
- Division of Hematology, Department of Medicine, The Ohio State University, 460 W 10th Ave., Columbus, OH 43210, USA
| | - Narendranath Epperla
- Division of Hematology, Department of Medicine, The Ohio State University, 460 W 10th Ave., Columbus, OH 43210, USA
| | - Timothy Voorhees
- Division of Hematology, Department of Medicine, The Ohio State University, 460 W 10th Ave., Columbus, OH 43210, USA
| | - Rina Li Welkie
- Division of Hematology, Department of Medicine, The Ohio State University, 460 W 10th Ave., Columbus, OH 43210, USA
| | - Ying Huang
- Division of Hematology, Department of Medicine, The Ohio State University, 460 W 10th Ave., Columbus, OH 43210, USA
| | - Gregory K. Behbehani
- Division of Hematology, Department of Medicine, The Ohio State University, 460 W 10th Ave., Columbus, OH 43210, USA
| | - Xiaoli Zhang
- Center for Biostatistics, Department of Biomedical Informatics, The Ohio State University, Columbus, OH 43210, USA
| | - Eric McLaughlin
- Center for Biostatistics, Department of Biomedical Informatics, The Ohio State University, Columbus, OH 43210, USA
| | - Wing K. Chan
- Division of Hematology, Department of Medicine, The Ohio State University, 460 W 10th Ave., Columbus, OH 43210, USA
| | - Jonathan E. Brammer
- Division of Hematology, Department of Medicine, The Ohio State University, 460 W 10th Ave., Columbus, OH 43210, USA
| | - Samantha Jaglowski
- Division of Hematology, Department of Medicine, The Ohio State University, 460 W 10th Ave., Columbus, OH 43210, USA
| | - John C. Reneau
- Division of Hematology, Department of Medicine, The Ohio State University, 460 W 10th Ave., Columbus, OH 43210, USA
| | - Beth A. Christian
- Division of Hematology, Department of Medicine, The Ohio State University, 460 W 10th Ave., Columbus, OH 43210, USA
| | - Basem M. William
- Blood and Marrow Transplant and Cell Therapy Program, OhioHealth, 500 Thomas Ln #A3, Columbus, OH 43214, USA
| | - Jonathon B. Cohen
- Department of Hematology and Medical Oncology, Winship Cancer Institute, Emory University, 1365 Clifton Road NE, B4013, Atlanta, GA 30322, USA
| | - Robert A. Baiocchi
- Division of Hematology, Department of Medicine, The Ohio State University, 460 W 10th Ave., Columbus, OH 43210, USA
| | - Kami Maddocks
- Division of Hematology, Department of Medicine, The Ohio State University, 460 W 10th Ave., Columbus, OH 43210, USA
| | - Kristie A. Blum
- Department of Hematology and Medical Oncology, Winship Cancer Institute, Emory University, 1365 Clifton Road NE, B4013, Atlanta, GA 30322, USA
| | - Lapo Alinari
- Division of Hematology, Department of Medicine, The Ohio State University, 460 W 10th Ave., Columbus, OH 43210, USA
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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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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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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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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 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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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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11
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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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12
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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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13
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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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15
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Chan WK, Suwannasaen D, Throm RE, Li Y, Eldridge PW, Houston J, Gray JT, Pui CH, Leung W. Chimeric antigen receptor-redirected CD45RA-negative T cells have potent antileukemia and pathogen memory response without graft-versus-host activity. Leukemia 2015; 29:387-95. [PMID: 24888271 PMCID: PMC4275423 DOI: 10.1038/leu.2014.174] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2014] [Accepted: 05/23/2014] [Indexed: 12/27/2022]
Abstract
Chimeric antigen receptor (CAR)-redirected cellular therapy is an attractive modality for cancer treatment. We hypothesized that allogeneic CAR-engineered CD45RA-negative T cells can control cancer and infection without the risk of graft-versus-host disease (GVHD). We used CD19(+) MLL-rearranged leukemia as prototype because it is an aggressive and generally drug-resistant malignancy. CD45RA(-) cells that were transduced with anti-CD19 CAR containing 4-1BB and CD3ζ signaling domains effectively lysed MLL-rearranged leukemia cell lines and primary blasts in vitro. In a disseminated leukemia mouse model, CAR(+)CD45RA(-) cells significantly reduced leukemia burdens and prolonged overall survival without GVHD. CAR(+) cells were sustainable in blood, and all the treated mice remained leukemia-free even after they were re-challenged with leukemia cells. Despite the transduction process, CD45RA(-) cells retained recall activity both in vitro and in vivo against human pathogens commonly found in cancer patients. In comparison with CD45RA(+) cells, CD45RA(-) cells showed less allogeneic activity in mixed leukocyte reactions and in mouse models. Thus, the use of CAR(+)CD45RA(-) cells can separate GVHD from graft-versus-malignancy effect and infection control. These cells should also be useful in nontransplant settings and may be administered as off-the-shelf third-party cells.
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Affiliation(s)
- W K Chan
- Department of Bone Marrow Transplantation and Cellular Therapy, St Jude Children's Research Hospital, Memphis, TN, USA
| | - D Suwannasaen
- Department of Bone Marrow Transplantation and Cellular Therapy, St Jude Children's Research Hospital, Memphis, TN, USA
| | - R E Throm
- Vector Laboratory, Department of Experimental Hematology, St Jude Children's Research Hospital, Memphis, TN, USA
| | - Y Li
- Department of Bone Marrow Transplantation and Cellular Therapy, St Jude Children's Research Hospital, Memphis, TN, USA
| | - P W Eldridge
- Human Application Laboratory, St Jude Children's Research Hospital, Memphis, TN, USA
| | - J Houston
- Department of Bone Marrow Transplantation and Cellular Therapy, St Jude Children's Research Hospital, Memphis, TN, USA
| | - J T Gray
- Vector Laboratory, Department of Experimental Hematology, St Jude Children's Research Hospital, Memphis, TN, USA
| | - C-H Pui
- Department of Oncology, St Jude Children's Research Hospital, Memphis, TN, USA
- Department of Pediatrics, University of Tennessee, Memphis, TN, USA
| | - W Leung
- Department of Bone Marrow Transplantation and Cellular Therapy, St Jude Children's Research Hospital, Memphis, TN, USA
- Department of Pediatrics, University of Tennessee, Memphis, TN, USA
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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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18
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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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19
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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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20
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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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21
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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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23
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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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24
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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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25
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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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26
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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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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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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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Chan WK, Borghols WJH, Mulder FM. Direct observation of space charge induced hydrogen ion insertion in nanoscale anatase TiO2. Chem Commun (Camb) 2008:6342-4. [DOI: 10.1039/b812311j] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [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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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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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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Lau RKL, Kwok ACM, Chan WK, Zhang TY, Wong JTY. Mechanical characterization of cellulosic thecal plates in dinoflagellates by nanoindentation. J Nanosci Nanotechnol 2007; 7:452-7. [PMID: 17450778] [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: 05/15/2023]
Abstract
Dinoflagellates constitute an important group of microorganisms. Symbiotic dinoflagellates are responsible for the primary production of coral reef ecosystems and the phenomenon of their demise is known as "coral bleaching." Blooming of the planktonic dinoflagellates is the major cause of "red tides." Many dinoflagellates have prominent membrane-bound thecal plates at their cell cortices. These thecal plates have high cellulose content and are biologically fabricated into various shapes. However, the mechanical properties of theca have not previously been characterized; understanding these properties, including hardness and elastic modulus, will give insights into the ecological significance and biotechnological potential of bio-fabricated structures. A series of nanoindentation tests were performed on various locations of cellulosic thecal plates isolated from the dinoflagellates Alexandrium catenella and Lingulodinium polyedrum. Despite having transparent properties, thecal plates possess mechanical properties comparable to softwood cell walls, implicating their role as a protective cell covering. Consistent measurements were obtained when indentation was performed at various locations, which contrasts with the high variability of cellulose microfibers from plant sources. The present study demonstrated the novel properties of this potential new source of cellulose.
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Affiliation(s)
- Ringo K L Lau
- Department of Biology, Hong Kong University of Science and Technology, Clearwater Bay, Kowloon, Hong Kong SAR, People's Republic of China
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Tong WY, Djurisić AB, Xie MH, Ng ACM, Cheung KY, Chan WK, Leung YH, Lin HW, Gwo S. Metal Phthalocyanine Nanoribbons and Nanowires. J Phys Chem B 2006; 110:17406-13. [PMID: 16942077 DOI: 10.1021/jp062951q] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Nanoribbons and nanowires of different metal phthalocyanines (copper, nickel, iron, cobalt, and zinc), as well as copper hexadecafluorophthalocyanine (F(16)CuPc), have been grown by organic vapor-phase deposition. Their properties, as a function of substrate type, source-to-substrate distance, and substrate temperature, were studied by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and absorption measurements. The size and morphology of the nanostructures were found to be mainly determined by the substrate temperature. The crystal structure was dependent on the substrate temperature as well. At substrate temperatures below 200 degrees C, in addition to straight nanoribbons, twisted nanoribbons were found for all investigated materials except F(16)CuPc, which formed helical nanoribbons upon exposure to an electron beam. The formation of different nanostructures (nanoribbons, twisted nanoribbons, and helical nanoribbons) is discussed.
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Affiliation(s)
- W Y Tong
- Department of Physics, University of Hong Kong, Pokfulam Road, Hong Kong
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Tse CW, Leung YH, Tam KH, Chan WK, Djurisić AB. Tailoring and modifications of a ZnO nanostructure surface by the layer-by-layer deposition technique. Nanotechnology 2006; 17:3563-3568. [PMID: 19661605 DOI: 10.1088/0957-4484/17/14/034] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [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
Different ZnO nanostructures have been modified using the layer-by-layer polyelectrolyte deposition process. The polymer multilayers were deposited on free standing ZnO tetrapods, ZnO tetrapods on a substrate and ZnO nanorod arrays. In addition, attachment of metallic (Au) nanoparticles to the ZnO nanostructure surface using layer-by-layer deposition was demonstrated. The properties of the ZnO nanostructures with modified surfaces were investigated by electron microscopy, absorption and photoluminescence measurements. A linear increase in polymer thickness with the number of polymer multilayers was confirmed by absorption and transmission electron microscopy. The technique can be readily extended to different nanoparticles and different morphologies of ZnO.
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Affiliation(s)
- Chui Wan Tse
- Department of Chemistry, The Univeristy of Hong Kong, Pokfulam Road, Hong Kong
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Chan WK, Chung TS, Lau BST, Law HT, Yeung AKM, Wong CHY. Management of hypertension by private doctors in Hong Kong. Hong Kong Med J 2006; 12:115-8. [PMID: 16603778] [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: 05/08/2023] Open
Abstract
OBJECTIVE To investigate the management of hypertension by private doctors in Hong Kong. DESIGN Self-administered questionnaire survey. SETTING Hong Kong. PARTICIPANTS Private doctors from all districts in Hong Kong selected by simple random sampling from the website of "The Hong Kong Doctors Homepage" from March to June 2005. MAIN OUTCOME MEASURES Practice of blood pressure measurement and the treatment prescribed to hypertensive patients. RESULTS A total of 225 (46%) completed questionnaires were analysed. Only 24.4% of the respondents measured blood pressure in all new patients aged above 18 years. A total of 28.0% of doctors reported that hypertensive status was unknown in over 30% of their patients prior to their first clinic visit when it was consequently diagnosed. Calcium channel blockers (31%), angiotensin-converting enzyme inhibitors (28.5%), diuretics (27.5%), and beta-blockers (21.2%) were the most commonly prescribed antihypertensive medication. Drug efficacy was the reason cited by more than half (56.9%) of doctors for selecting a given drug. Public education about hypertension was considered insufficient by 66.2% of doctors and 32% believed that self-medication would have a very significant effect on drug compliance. CONCLUSIONS In private clinics, blood pressure measurement should become a routine procedure. There is a need to raise public awareness of hypertension.
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Affiliation(s)
- W K Chan
- Division of Cardiology, Department of Medicine and Geriatrics, United Christian Hospital, Kwun Tong, Hong Kong.
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Mak YMW, Chan WK, Yue CSS. Barriers to participation in a phase II cardiac rehabilitation programme. Hong Kong Med J 2005; 11:472-5. [PMID: 16340024] [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: 05/05/2023] Open
Abstract
OBJECTIVES To identify barriers to participation in a phase II cardiac rehabilitation programme and measures that may enhance participation. DESIGN Prospective study. SETTING Regional hospital, Hong Kong. PATIENTS Cardiac patients recruited for a phase I cardiac rehabilitation programme from July 2002 to January 2003. MAIN OUTCOME MEASURES Reasons for not participating in a phase II cardiac rehabilitation programme. RESULTS Of the 193 patients recruited for a phase I cardiac rehabilitation programme, 152 (79%) patients, with a mean age of 70.3 years (standard deviation, 11.9 years), did not proceed to phase II programme. Eleven (7%) deaths occurred before commencement of phase II and 74 (49%) patients were considered physically unfit. Reasons for the latter included fractures, pain, or degenerative changes in the lower limbs (24%), and co-morbidities such as cerebrovascular accident (19%), chronic renal failure (11%), congestive heart failure (9%), and unstable angina (8%). Phase II rehabilitation was postponed until after completion of scheduled cardiac interventions in 13% of patients. Failure of physicians to arrange the pre-phase II exercise stress test as per protocol was reported in 7% of patients. Other reasons were reported: work or time conflicts (16%), non-compliance with cardiac treatment (5%), financial constraints (4%), self-exercise (3%), fear after exercise stress testing (3%), and patients returning to their original cardiologists for treatment (3%). CONCLUSIONS A significant (79%) proportion of patients did not proceed to a phase II cardiac rehabilitation programme for a variety of reasons. These included physical unfitness, work or time conflicts, and need to attend scheduled cardiac interventions. Further studies are required to determine how to overcome obstacles to cardiac rehabilitation.
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Affiliation(s)
- Y M W Mak
- Division of Cardiology, Department of Medicine and Geriatrics, United Christian Hospital, Kwun Tong, Hong Kong
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Chau TN, Yim KF, Mok NS, Chan WK, Leung VKS, Leung MF, Lai ST. Clopidogrel-induced hepatotoxicity after percutaneous coronary stenting. Hong Kong Med J 2005; 11:414-6. [PMID: 16219965] [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: 05/04/2023] Open
Abstract
Clopidogrel, an adenosine diphosphate receptor blocker, is widely used as an adjunctive antiplatelet therapy in acute coronary syndrome and percutaneous coronary stenting. The occurrence of hepatotoxicity is rare. We describe the occurrence of symptomatic liver disease in a 74-year-old man 5 weeks following commencement of therapy with clopidogrel. The reported cases of clopidogrel-induced hepatotoxicity are reviewed and the clinical significance of this event are discussed.
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Affiliation(s)
- T N Chau
- Department of Medicine and Geriatrics, United Christian Hospital, Kwun Tong, Hong Kong.
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Cheung KMC, Lu WW, Luk KDK, Wong CT, Chan D, Shen JX, Qiu GX, Zheng ZM, Li CH, Liu SL, Chan WK, Leong JCY. Vertebroplasty by use of a strontium-containing bioactive bone cement. Spine (Phila Pa 1976) 2005; 30:S84-91. [PMID: 16138071 DOI: 10.1097/01.brs.0000175183.57733.e5] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN A review of the laboratory and clinical data for a new strontium-containing hydroxyapatite bioactive bone cement. OBJECTIVES To compare the properties of the strontium-containing bioactive bone cement with those of polymethyl methacrylate (PMMA) and hydroxyapatite (HA) bone cements. SUMMARY OF BACKGROUND DATA Vertebroplasty and kyphoplasty using conventional PMMA bone cements have been effectively used to treat osteoporotic spine fractures with good short- and medium-term results. However, PMMA has some undesirable properties, including its high setting temperature, lack of osseointegration, and large stiffness mismatch with osteoporotic bone. These properties are responsible for some postoperative complications. METHODS Strontium-containing hydroxyapatite (Sr-HA) bioactive bone cement consists of a filler blend of strontium-containing hydroxyapatite, fumed silica and benzoyl peroxide; and a resin blend of bisphenol A diglycidylether methacrylate, triethylene glycol dimethacrylate, poly(ethylene glycol) methacrylate, and N, N-dimethyl-p-toluidine. Its properties, including mechanical strength, setting temperature, biocompatibility, and osseoinduction, were compared with other cements in vitro and in vivo. Early clinical results are presented. RESULTS The Sr-HA cement has a setting time of 15 to 18 minutes, a maximum setting temperature of 58 degrees C, a compressive strength of 40.9 MPa, bending strength of 31.3 MPa, and a bending modulus of 1,408 MPa. The bending strength and modulus are closer to human cancellous bone. Sr-HA cement promotes osteoblast attachment and mineralization in vitro and bone growth and osseointegration in vivo. In a pilot study, 23 cases of osteoporotic fractures treated with this cement with a mean follow-up of 18 months suggest that it is as effective as PMMA in relieving pain. DISCUSSIONS Oral strontium has been shown to induce new bone formation and is effective in reducing fracture risk in osteoporosis. Our data suggest that strontium delivered locally has the same effect; thus, the combination of strontium with HA in a cement with a low setting temperature, adequate stiffness, and low viscosity makes this a good bioactive cement for vertebroplasty and kyphoplasty.
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Affiliation(s)
- Kenneth M C Cheung
- Department of Orthopaedics and Traumatology, University of Hong Kong, Hong Kong, China.
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Lo TK, Lo IFM, Chan WK, Tong TMF, Lam STS. Chromosomal abnormalities and FMR1 gene premutation in Chinese women with premature menopause. Hong Kong Med J 2005; 11:243-50. [PMID: 16085940] [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: 05/03/2023] Open
Abstract
OBJECTIVE To study the prevalence of chromosomal abnormalities and FMR1 gene premutation in Chinese women with premature menopause in Hong Kong. DESIGN Retrospective study. SETTING Clinical Genetic Service, Hong Kong. PARTICIPANTS Chinese women with premature menopause referred for cytogenetic study from January 1983 to November 2003. MAIN OUTCOME MEASURES Chromosomal abnormalities, FMR1 gene premutation. RESULTS Chromosomal abnormalities were present in 15.6% of Chinese women who suffered premature menopause. X-chromosome abnormality was involved in over 80% of cases. FMR1 gene premutation was present in 0.86% of 116 cases screened for this abnormality. The predominance of X-chromosome abnormality accounted for the shorter stature, younger menopausal age, and higher prevalence of dysmorphic features among the cytogenetically abnormal patients. However, on logistic regression, no clinical feature was significantly correlated with cytogenetic abnormality. CONCLUSIONS The prevalence of chromosomal abnormalities among Hong Kong Chinese women who suffer premature menopause was comparable with that of Caucasian and Chinese populations elsewhere. Because clinical features are poor predictors of cytogenetic abnormality, a pragmatic approach to screening is advocated. The carrier rate of fragile X premutation in these women appeared lower than that of Caucasians. Nevertheless, a search for FMR1 gene premutation, in addition to conventional chromosomal study, has important implication for prenatal diagnosis and fertility management for the extended family.
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Affiliation(s)
- T K Lo
- Department of Obstetrics and Gynaecology, Kwong Wah Hospital, 25 Waterloo Road, Hong Kong.
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Wong CT, Lu WW, Chan WK, Cheung KMC, Luk KDK, Lu DS, Rabie ABM, Deng LF, Leong JCY. In vivo cancellous bone remodeling on a strontium-containing hydroxyapatite (sr-HA) bioactive cement. J Biomed Mater Res A 2004; 68:513-21. [PMID: 14762931 DOI: 10.1002/jbm.a.20089] [Citation(s) in RCA: 120] [Impact Index Per Article: 6.0] [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: 11/12/2022]
Abstract
The purpose of this study was to investigate the in vivo bone response to the strontium-containing hydroxyapatite (Sr-HA) bioactive bone cement injected into the cancellous bone. Sr-HA cement was injected into the iliac crest of rabbits for 1, 3, and 6 months. Active bone formation and remodeling were observed after 1 month. Newly formed bone was observed to grow onto the bone cement after 3 months. Thick osteoid layer with osteoblasts formed along the bone and guided over the bone cement surface reflected the stimulating effect of Sr-HA. From scanning electron microscopy (SEM) and energy-dispersive X-ray (EDX) analysis, high calcium and phosphorus levels were detected at the interface with a thick layer of 70 microm in width, and fusion of Sr-HA with the bone was observed. Blood vessels were found developing in remodeling sites. The affinity of bone on Sr-HA cement was increased from 73.55 +/- 3.50% after 3 months up to 85.15 +/- 2.74% after 6 months (p < 0.01). In contrast to Sr-HA cement, poly(methyl methacrylate) (PMMA) bone cement was neither osteoconductive nor bioresorbable. Results show that the Sr-HA cement is biocompatible and osteoconductive, which is suitable for use in treating osteoporotic vertebral fractures.
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Affiliation(s)
- C T Wong
- Department of Orthopaedic Surgery, Faculty of Medicine, The University of Hong Kong, Hong Kong SAR
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Ho SSY, Su LL, Chan WK, Chua SE, Lim RPY, Biswas A, Choolani M. Ultrarapid prenatal detection of Down syndrome using real-time multiplex polymerase chain reaction (PCR) in amniotic fluid. Ann Acad Med Singap 2004; 33:S91-2. [PMID: 15651231] [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] [Subscribe] [Scholar Register] [Indexed: 05/01/2023]
Affiliation(s)
- S S Y Ho
- Department of Obstetrics and Gynaecology, National University Hospital, Singapore.
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Mok NS, Priori SG, Napolitano C, Chan KK, Bloise R, Chan HW, Fung WH, Chan YS, Chan WK, Lam C, Chan NY, Tsang HH. Clinical profile and genetic basis of Brugada syndrome in the Chinese population. Hong Kong Med J 2004; 10:32-7. [PMID: 14967853] [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: 04/28/2023] Open
Abstract
OBJECTIVE To study the clinical profile and genetic basis of Brugada syndrome in Chinese patients. DESIGN Prospective observational study. SETTING Seven regional public hospitals, Hong Kong. MAIN OUTCOME MEASURES The clinical and follow-up data of 50 patients (47 men, 3 women; mean age, 53 years) were collected, and genetic data of 36 probands and eight family members of three genotyped probands were analysed. RESULTS Eight patients survived sudden cardiac death (group A), 12 had syncope of unknown origin but no sudden death (group B), and 30 were asymptomatic before recognition of Brugada syndrome (group C). Programmed electrical stimulation induced sustained ventricular arrhythmias in 88% (7/8), 82% (9/11), and 27% (3/11) of patients in group A, group B, and group C, respectively. New arrhythmic events occurred in 50% (4/8) of patients in group A and 17% (2/12) of patients in group B after a mean follow-up period of 30 (standard deviation, 13) months and 25 (7) months, respectively. All group C patients remained asymptomatic during a mean follow-up period of 25 (standard deviation, 11) months. Five of 36 probands and three of eight family members who underwent genetic testing were found to have a mutation in their SCN5A gene. CONCLUSIONS Chinese patients with Brugada syndrome who are symptomatic have a high likelihood of arrhythmia recurrence, whereas asymptomatic patients enjoy a good short-term prognosis. The prevalence of SCN5A mutation among probands is 14%. Thus, Chinese patients with Brugada syndrome share with their western counterparts similar clinical and genetic heterogeneity.
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Affiliation(s)
- N S Mok
- Department of Medicine and Geriatrics, Princess Margaret Hospital, Laichikok, Hong Kong.
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Wong CT, Chen QZ, Lu WW, Leong JCY, Chan WK, Cheung KMC, Luk KDK. Ultrastructural study of mineralization of a strontium-containing hydroxyapatite (Sr-HA) cementin vivo. ACTA ACUST UNITED AC 2004; 70:428-35. [PMID: 15293316 DOI: 10.1002/jbm.a.30097] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.5] [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: 11/09/2022]
Abstract
The purpose of this study was to investigate the mineralization leading to osseointegration of strontium-containing hydroxyapatite (Sr-HA) bioactive bone cement injected into cancellous bone in vivo. Sr-HA cement was injected into the ilium of rabbits for 1, 3, and 6 months. The bone mineralization area was found to be largest at 3 months, then at 1 month, and smallest at 6 months (p < 0.01) measured with tetracycline labeling. Osseointegration of Sr-HA cement was achieved at 3 months as observed by scanning electron microscopy. A high calcium and phosphorus area was observed at the interface of bone-Sr-HA cement determined by energy-dispersive X-ray analysis. Transmission electron microscopy gave evidence of the mechanism of bone formation. Dissolution of Sr-HA into debris by the bone remodeling process was thought to increase the concentration of calcium and phosphorus at the interface of bone-Sr-HA cement and stimulate bone formation. Crystalline Sr-HA formed an amorphous layer and dissolved into the surrounding solution, then apatite crystallites were precipitated and formed new bone at 3 months. This young bone then becomes mature bone, which bonds tightly to the Sr-HA cement with collagen fibers inserted perpendicularly after 6 months.
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Affiliation(s)
- C T Wong
- Department of Orthopaedic Surgery, Faculty of Medicine, The University of Hong Kong, Hong Kong SAR
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Abstract
Fluid dynamic forces in centrifugal blood pump impellers are of key importance in destruction of red blood cells (RBCs) because high rotational speed leads to strong interaction between the impeller and the RBCs. In this paper, three-dimensional models of five different blade geometries are investigated numerically using the commercial software CFX-TASCflow, and the streaklines of RBCs are obtained using the Lagrangian particle tracking method. In reality, RBCs pass through the pump along complicated paths resulting in a highly irregular loading condition for each RBC. In order to enable the prediction of blood damage under the action of these complex-loading conditions, a cumulative damage model for RBCs was adopted in this paper. The numerically simulated percent hemoglobin (%HB) released as RBCs traversed the impeller and volute was examined. It was observed that the residence time of particles in the blade passage is a critical factor in determining hemolytic effects. This, in turn, is a function of the blade geometry. In addition, it was observed that the volute profile is an important influence on the computed HB% released.
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Affiliation(s)
- W K Chan
- School of Mechanical and Production Engineering, Nanyang Technological University, Singapore, Republic of Singapore
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47
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Abstract
This article presents computational studies on the effects of inlet guide vanes (IGVs) on the flow pattern and shear stress in a centrifugal blood pump. The effect of IGVs is to introduce a pre-swirl to fluid particles entering the impeller with the intention that the fluid particles will travel along the blade profile. Currently, most commercial centrifugal blood pumps employ straight radial impeller blades that are not hydrodynamically ideal for a good flow pattern within the blade passage. Flow separation and formation of vortices within the blade passage are believed to increase the degree of hemolysis and thrombosis. These are causes for blood clotting that will lead to malfunctioning of ventricular assist devices. Four IGVs of different geometrical profiles have been numerically investigated using a commercial software program CFX-Tascflow. The pump is operated at 2,000 rpm, and the results revealed that the relative flow patterns in the blade passage have been dramatically altered. The size of the vortices was reduced, and the pressure contours indicated a gradual rise from the impeller leading edge to the trailing edge. However, inclusion of IGV causes a drop in the pressure head generated. Higher frictional losses are incurred as fluid particles passed through the IGV. In addition, the IGV modifies the inlet velocity triangles, and this also contributes to a drop in the pressure head generated that is consistent with Euler's pump theory. The change in the flow patterns and the gradual variation of the pressure contours have led to lower shear stress within the blade passages as compared to the case without IGVs.
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Affiliation(s)
- W K Chan
- School of Mechanical and Production Engineering, Nanyang Technological University, Republic of Singapore
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48
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Abstract
This paper reports the synthesis and opto-electronic properties of different conjugated polymers that contain the diimine complexes of ruthenium or rhenium. Conjugated poly(phenylene vinylene)s that contain aromatic 1,3,4-oxadiazole and 2,2'-bipyridine units on the main chain were synthesized by the palladium catalyzed olefinic coupling reaction. Other types of polymers based on 1,10-phenanthroline bis(2,2-bipyridyl) ruthenium(II) or chlorotricarbonyl rhenium(I) complexes were also synthesized by the same reaction. In general, these polymers exhibit two absorption bands due to the pi - pi transition of the conjugated main chain and the d-pi* metal-to-ligand charge-transfer transition of the metal complex. As a result, the photosensitivity of the polymers beyond 500 nm was enhanced. Charge-carrier mobility measurements showed that the presence of metal complexes could facilitate the charge-transport process, and the enhancement in carrier mobility was dependent on the metal content in the polymer. In addition, we have also demonstrated that the ruthenium complex could act as both photosensitizer and light emitter. Photovoltaic cells were constructed, and they were subjected to irradiation with a xenon arc lamp. Under illumination, the short circuit current and the open circuit voltage were measured to be 0.05 mAcm(-2) and 0.35 V, respectively. The polymers were fabricated into single-layer emitting devices, and light emission was observed when the device was subjected to forward bias. The maximum luminance was determined to be 300 cdm(-2), and the external quantum efficiency was approximately 0.05 to 0.2%. Although the efficiency was relatively low when compared with other devices based on organic materials, we have demonstrated the first examples of using transition metal complexes for both photovoltaic and light-emitting applications.
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Affiliation(s)
- P K Ng
- Department of Chemistry, University of Hong Kong, Hong Kong
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49
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Lim L, Tan DT, Chan WK. Therapeutic use of Bausch & Lomb PureVision contact lenses. CLAO J 2001; 27:179-85. [PMID: 11725978] [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: 02/22/2023]
Abstract
PURPOSE To evaluate the Bausch & Lomb PureVision contact lens as a continuous wear contact lens for therapeutic indications in a prospective open-ended non-randomized clinical trial. METHODS Patients with a variety of corneal and ocular surface disease conditions presenting at the Singapore National Eye Centre who required therapeutic continuous contact lens wear were enrolled. Therapeutic indications included pain relief, corneal protection, and enhancement of corneal wound healing. Success or failure of specific treatment indications was assessed in all cases, with evaluation of lens performance and fit characteristics, and the presence of ocular complications or lens-related complications was noted. RESULTS There were 54 patients (54 eyes), and the mean duration of continuous contact lens wear was 1.1 months. Conditions treated included post-surgical indications (n = 36) (post-keratoplasty or ocular surface transplantation, post-LASIK or PRK surgery) bullous keratopathy (n = 7), chemical burns (n = 3), epithelial abrasions or recurrent corneal erosion syndromes (n = 3), corneal perforations (n = 3), neurotrophic ulcer (n = 1), and corneal laceration (n = 1). For the indication of corneal healing (40 eyes), improved healing was noted in 38 eyes (96%), with full healing occurring in 33 eyes (83%). For pain relief (28 eyes), 27 patients (96%) had considerable or complete pain relief, and the remaining patient reported partial pain relief. For corneal protection (21 eyes), lens wear was fully protective in all cases. The lens performance and fitting characteristics surpassed any previous therapeutic lenses used by the investigators. Complications related to contact lens wear were limited to one case of a culture-negative corneal infiltrate requiring cessation of therapeutic lens wear and one case of a loosely fit lens. CONCLUSIONS Our results show that the PureVision contact lens exhibits good safety and efficacy when utilized as a continuous wear therapeutic lens. With the theoretical advantage of increased oxygen transmissibility reducing the risk of hypoxia-related complications, this new lens may be one step closer to the ideal therapeutic contact lens. The PureVision contact lens is now our primary bandage lens of choice in our corneal, external disease, and refractive surgery services.
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Affiliation(s)
- L Lim
- Singapore National Eye Centre, Singapore.
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Ma P, Sivaloganathan B, Reddy PK, Chan WK, Lam TJ. Ontogeny of alpha-amylase gene expression in sea bass larvae (Lates calcarifer). Mar Biotechnol (NY) 2001; 3:463-469. [PMID: 14961339 DOI: 10.1007/s10126-001-0018-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The enzymatic activities of alpha-amylase and its corresponding messenger RNA levels in developing sea bass (Lates calcarifer) larvae were studied from hatching until 27 days post hatching (dph). An increasing activity of amylase enzyme was measured until 5 dph, and the activity gradually decreased thereafter and reached a constant level by 12 dph. To achieve a better understanding of the molecular mechanisms underlying amylase expression, we have cloned and sequenced a 318-bp fragment of alpha-amylase complementary DNA. Based on this sequence, a real-time reverse transcriptase polymerase chain reaction technique to monitor the changes in the mRNA levels in the larvae was developed. A correlation between enzymatic activity and mRNA level of alpha-amylase could be demonstrated during the early development of sea bass larvae. This suggests that the changes in alpha-amylase are controlled at least at the transcriptional level during early larval development of sea bass.
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Affiliation(s)
- P Ma
- Department of Biological Sciences, National University of Singapore, 10 Kent Ridge Crescent, Singapore 119260
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