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Qi W, Wu HC, Chan SC. MDF-Net: A Multi-Scale Dynamic Fusion Network for Breast Tumor Segmentation of Ultrasound Images. IEEE Trans Image Process 2023; 32:4842-4855. [PMID: 37639409 DOI: 10.1109/tip.2023.3304518] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/31/2023]
Abstract
Breast tumor segmentation of ultrasound images provides valuable information of tumors for early detection and diagnosis. Accurate segmentation is challenging due to low image contrast between areas of interest; speckle noises, and large inter-subject variations in tumor shape and size. This paper proposes a novel Multi-scale Dynamic Fusion Network (MDF-Net) for breast ultrasound tumor segmentation. It employs a two-stage end-to-end architecture with a trunk sub-network for multiscale feature selection and a structurally optimized refinement sub-network for mitigating impairments such as noise and inter-subject variation via better feature exploration and fusion. The trunk network is extended from UNet++ with a simplified skip pathway structure to connect the features between adjacent scales. Moreover, deep supervision at all scales, instead of at the finest scale in UNet++, is proposed to extract more discriminative features and mitigate errors from speckle noise via a hybrid loss function. Unlike previous works, the first stage is linked to a loss function of the second stage so that both the preliminary segmentations and refinement subnetworks can be refined together at training. The refinement sub-network utilizes a structurally optimized MDF mechanism to integrate preliminary segmentation information (capturing general tumor shape and size) at coarse scales and explores inter-subject variation information at finer scales. Experimental results from two public datasets show that the proposed method achieves better Dice and other scores over state-of-the-art methods. Qualitative analysis also indicates that our proposed network is more robust to tumor size/shapes, speckle noise and heavy posterior shadows along tumor boundaries. An optional post-processing step is also proposed to facilitate users in mitigating segmentation artifacts. The efficiency of the proposed network is also illustrated on the "Electron Microscopy neural structures segmentation dataset". It outperforms a state-of-the-art algorithm based on UNet-2022 with simpler settings. This indicates the advantages of our MDF-Nets in other challenging image segmentation tasks with small to medium data sizes.
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Lee LC, Weigelhofer G, Hein T, Chan SC, Liou YS, Liao CS, Shiah FK, Yu YL, Lee TY, Huang JC. Transition of carbon-nitrogen coupling under different anthropogenic disturbances in subtropical small mountainous rivers. Sci Total Environ 2023; 870:162017. [PMID: 36739020 DOI: 10.1016/j.scitotenv.2023.162017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2022] [Revised: 12/31/2022] [Accepted: 01/31/2023] [Indexed: 06/18/2023]
Abstract
The commonly observed inverse relationship between dissolved organic carbon (DOC) and nitrate (NO3-) concentrations in aquatic systems can be explained by stoichiometric and thermodynamic principles regulating microbial assimilation and dissimilation processes. However, the interactive effects of human activities and dissolved oxygen (DO) on the DOC and DIN (dissolved inorganic nitrogen, mainly composed of NO3--N and NH4+-N) relations are not well identified, particularly in subtropical small mountainous rivers (SMRs). Here, we investigated the exports and relations of DOC-DIN in 42 Taiwan SMRs under different anthropogenic disturbances. Results showed that the island-wide mean concentrations of the three solutes in streams are generally low, yet the abundant rainfall and persistent supply contrarily lead to disproportional high DOC and DIN yields. The inverse DOC-NO3--N relation does not appear under well‑oxygenated conditions, regardless of low or high human disturbance. However, a significant inverse relationship between DOC-NO3--N would emerge in highly-disturbed watersheds under low-oxygenated conditions (mean annual DO <6.5 mg L-1), where excess N accumulates as NH4+-N rather than NO3--N. The controlling mechanism of DOC-DIN relations would shift from energetic constraints to redox constraints in low-oxygenated conditions. Although riverine concentrations of DOC, NO3--N, and NH4+-N could be elevated by human activities, the transition of DOC-DIN relation pattern is directly linked to DO availability. Understanding the mechanism that drives CN coupling is critical for assessing the ecosystem function in the delivery and retention of DOC and DIN in aquatic ecosystems.
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Affiliation(s)
- Li-Chin Lee
- Department of Geography, National Taiwan University, Taipei, Taiwan; Department of Water, Atmosphere and Environment, Institute of Hydrobiology and Aquatic Ecosystem Management, University of Natural Resources and Life Sciences, Vienna, Austria
| | - Gabriele Weigelhofer
- Department of Water, Atmosphere and Environment, Institute of Hydrobiology and Aquatic Ecosystem Management, University of Natural Resources and Life Sciences, Vienna, Austria; WasserCluster Lunz, Lunz am See, Austria
| | - Thomas Hein
- Department of Water, Atmosphere and Environment, Institute of Hydrobiology and Aquatic Ecosystem Management, University of Natural Resources and Life Sciences, Vienna, Austria; WasserCluster Lunz, Lunz am See, Austria; Christian Doppler Laboratory for Meta Ecosystem Dynamics in Riverine Landscapes, University of Natural Resources and Life Sciences, Vienna, Austria
| | - Shin-Chien Chan
- Department of Geography, National Changhua University of Education, Changhua, Taiwan
| | - Ying-San Liou
- Department of Natural Resources and Environmental Studies, National Dong Hwa University, Hualien, Taiwan
| | - Chien-Sen Liao
- Department of Biological Science and Technology, I-Shou University, Kaohsiung, Taiwan
| | - Fuh-Kwo Shiah
- Research Center for Environmental Changes, Academia Sinica, Taipei, Taiwan
| | - Yu-Lin Yu
- Department of Geography, National Taiwan University, Taipei, Taiwan
| | - Tsung-Yu Lee
- Department of Geography, National Taiwan Normal University, Taipei, Taiwan
| | - Jr-Chuan Huang
- Department of Geography, National Taiwan University, Taipei, Taiwan.
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Li P, Yu DSF, Yan BPY, Wong CW, Yue SCS, Chan CMC, Chan SC. Shortening pre-hospital time delay in patients with acute myocardial infarction using a modelling-based narrative intervention with a virtual heart attack experience: a randomized controlled trial. Eur Heart J 2021. [DOI: 10.1093/eurheartj/ehab724.1511] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Abstract
Background
Prolonged delay in seeking treatment by patients with acute myocardial infarction (AMI) remains a significant therapeutic gap. Previous mass-media campaigns or brief educational interventions were largely ineffective in shortening pre-hospital patient delay. The brevity and didactic nature of these interventions are inadequate to address complex decision-making encountered by patients with AMI.
Purpose
This randomized controlled trial examined the effects of a theory-driven modelling-based narrative intervention on AMI knowledge, care-seeking intention as indicated by attitudes and beliefs regarding care-seeking for AMI, prehospital delay time and use of ambulance among AMI survivors.
Methods
A total of 285 of patients with history of at least one AMI were randomized 1:1 to modelling-based narrative intervention (n=144) and control with didactic education (n=141). The modelling-based narrative intervention comprised 4 weekly group-based interactive sessions to engage participants in mental rehearsals of the perceptual-cognitive processes in recognizing and responding to AMI symptoms through a virtual heart attack experience, then followed by a booster session one month later The control group received a 4-weekly education on factual information about AMI with traditional didactic education approach. Study endpoints included AMI knowledge, attitudes and belief about care-seeking for AMI to be measured at baseline, (T0), 3 months (T1), 12 months (T2) and 24 months (T3) after the intervention. Prehospital delay time and use of ambulance for an AMI attack were tracked since patients' enrolment until T3 endpoint of the study.
Results
Generalized estimating equation analysis indicated that the participants in the intervention group had significantly greater improvement in attitudes and beliefs about care seeking for AMI symptoms at all endpoints than those in the control group (Table 1). There were no between-group differences in the change of AMI knowledge score over the baseline and 3- or 12-month endpoints, such difference became significant at 24-month endpoint. A total of 78 participants, including 38 (26.4%) in the intervention group and 40 (28.4%) in the control groups, had experienced AMI symptoms and admitted to an emergency department during the follow-up period. The participants in the intervention group showed significant reduction in prehospital delay time than the control group (p=0.031). There was no between-group difference on use of ambulance (p=0.422) for those participants who had symptom attack during the follow-up period.
Conclusion
This study demonstrated favorable effects in shortening prehospital time delay and promoting positive attitudes and beliefs regarding care-seeking for AMI symptoms among AMI survivors. A virtual heart attack experience helped support them through a cognitive-perceptual processes in recognizing and interpreting AMI symptoms.
Funding Acknowledgement
Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Early Career Scheme, Research Grants Council, Hong Kong
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Affiliation(s)
- P Li
- The University of Hong Kong, Hong Kong, Hong Kong
| | - D S F Yu
- The University of Hong Kong, Hong Kong, Hong Kong
| | - B P Y Yan
- The Chinese University of Hong Kong, Department of Medicine and Therapeutics, Hong Kong, China
| | - C W Wong
- Pok Oi Hospital, Department of Medicine & Geriatrics, Hong Kong, Hong Kong
| | - S C S Yue
- United Christian Hospital, Department of Medicine & Geriatrics, Hong Kong, Hong Kong
| | - C M C Chan
- Queen Elizabeth Hopsital, Department of Medicine, Hong Kong, Hong Kong
| | - S C Chan
- Pok Oi Hospital, Department of Medicine & Geriatrics, Hong Kong, Hong Kong
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Lin Z, Qin H, Chan SC. A New Probabilistic Representation of Color Image Pixels and Its Applications. IEEE Trans Image Process 2018; 28:2037-2050. [PMID: 30530362 DOI: 10.1109/tip.2018.2883580] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
This paper proposes a novel probabilistic representation of color image pixels (PRCI) and investigates its applications to similarity construction in motion estimation and image segmentation problems. The PRCI explores the mixture representation of the input image(s) as prior information and describes a given color pixel in terms of its membership in the mixture. Such representation greatly simplifies the estimation of the probability density function from limited observations and allows us to derive a new probabilistic pixel-wise similarity measure based on the continuous domain Bhattacharyya coefficient. This yields a convenient expression of the similarity measure in terms of the pixel memberships. Furthermore, this pixel-wise similarity is extended to measure the similarity between two image regions. The usefulness of the proposed pixel/region-wise similarities is demonstrated by incorporating them respectively in a dense image descriptor-based multi- layered motion estimation problem and an unsupervised image segmentation problem. Experimental results show that i) the integration of the proposed pixel-wise similarity in dense image-descriptor construction yields improved peak signal to noise ratio performance and higher tracking accuracy in the multi-layered motion estimation problem, and ii) the proposed similarity measures give the best performance in terms of all quantitative measurements in the unsupervised superpixel- based image segmentation of the MSRC and BSD300 datasets.
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Wong TCL, Fung JYY, Chok KSH, Cheung TT, Chan ACY, Dai WC, Ng KKC, Chan SC, Lo CM. Hepatitis B Vaccination in Patients Receiving Oral Antiviral Therapy Without Hepatitis B Immunoglobulin After Liver Transplant. Transplant Proc 2018; 50:3681-3688. [PMID: 30577255 DOI: 10.1016/j.transproceed.2018.07.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Revised: 06/22/2018] [Accepted: 07/04/2018] [Indexed: 02/08/2023]
Abstract
Our study aimed to determine if a double-dose pre-S containing hepatitis B virus (HBV) vaccination (Sci-B-Vac) could elicit an adequate and sustainable immune response in HBV patients who developed spontaneous hepatitis B surface antibody (anti-HBs) response after liver transplant. PATIENTS AND METHODS All patients who received transplants for HBV-related disease for >1 year with normal graft function and hepatitis B surface antigen seronegativity were evaluated. They received a 40-μg HBV vaccine if they were responders in our previous vaccine trial, if anti-HBs was positive for >1 year after liver transplant (LT), or if a peak anti-HBs at any time point after LT was >100 mIU/mL. Primary endpoint was the development of anti-HBs ≥ 10 mIU/mL from previous negative value or a 1-log increase from baseline. RESULTS A total of 86 patients were recruited; 5 were responders from a previous trial; 45 patients had detectable anti-HBs >1 year after LT, and 36 patients had an anti-HBs >100 mIU/mL. All (5/5, 100%) previous responders responded to booster vaccination. For the remaining 81 patients, 10 of 81 (12.3%) responded. CONCLUSION All previous responders responded to booster vaccination, implying durability and memory of HBV immune response, which is an important prerequisite for definitive host immunity for HBV. In patients who had spontaneous anti-HBs production after LT, a single vaccination can induce response in 12.3% of patients.
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Affiliation(s)
- T C L Wong
- Department of Surgery, Queen Mary Hospital, The University of Hong Kong, Hong Kong, China
| | - J Y Y Fung
- Department of Medicine, Queen Mary Hospital, The University of Hong Kong, Hong Kong, China
| | - K S H Chok
- Department of Surgery, Queen Mary Hospital, The University of Hong Kong, Hong Kong, China
| | - T T Cheung
- Department of Surgery, Queen Mary Hospital, The University of Hong Kong, Hong Kong, China
| | - A C Y Chan
- Department of Surgery, Queen Mary Hospital, The University of Hong Kong, Hong Kong, China
| | - W C Dai
- Department of Surgery, Queen Mary Hospital, The University of Hong Kong, Hong Kong, China
| | - K K C Ng
- Department of Surgery, Queen Mary Hospital, The University of Hong Kong, Hong Kong, China
| | - S C Chan
- Department of Surgery, Queen Mary Hospital, The University of Hong Kong, Hong Kong, China
| | - C M Lo
- Department of Surgery, Queen Mary Hospital, The University of Hong Kong, Hong Kong, China.
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Ma KW, Chok KS, Chan CK, Dai WC, Sin SL, Lau FL, Chan SC, Lo CM. Liver transplantation: a life-saving procedure following amatoxin mushroom poisoning. Hong Kong Med J 2017; 23:93-6. [PMID: 28184019 DOI: 10.12809/hkmj154616] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Affiliation(s)
- K W Ma
- Department of Surgery, Queen Mary Hospital, Pokfulam, Hong Kong
| | - K Sh Chok
- Department of Surgery, Queen Mary Hospital, Pokfulam, Hong Kong.,Department of Surgery, The University of Hong Kong, Pokfulam, Hong Kong
| | - C K Chan
- Hong Kong Poison Information Centre, United Christian Hospital, Kwun Tong, Hong Kong
| | - W C Dai
- Department of Surgery, Queen Mary Hospital, Pokfulam, Hong Kong.,Department of Surgery, The University of Hong Kong, Pokfulam, Hong Kong
| | - S L Sin
- Department of Surgery, Queen Mary Hospital, Pokfulam, Hong Kong
| | - F L Lau
- Hong Kong Poison Information Centre, United Christian Hospital, Kwun Tong, Hong Kong
| | - S C Chan
- Department of Surgery, The University of Hong Kong, Pokfulam, Hong Kong
| | - C M Lo
- Department of Surgery, Queen Mary Hospital, Pokfulam, Hong Kong.,Department of Surgery, The University of Hong Kong, Pokfulam, Hong Kong
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Siaw MYL, Ko Y, Malone DC, Tsou KYK, Lew YJ, Foo D, Tan E, Chan SC, Chia A, Sinaram SS, Goh KC, Lee JYC. Impact of pharmacist-involved collaborative care on the clinical, humanistic and cost outcomes of high-risk patients with type 2 diabetes (IMPACT): a randomized controlled trial. J Clin Pharm Ther 2017; 42:475-482. [PMID: 28449205 DOI: 10.1111/jcpt.12536] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Accepted: 03/29/2017] [Indexed: 12/14/2022]
Abstract
WHAT IS KNOWN AND OBJECTIVE With the increasing prevalence of diabetes, the physician-centred model is challenged to deliver holistic care in Asia. Diabetes may be managed effectively within a multidisciplinary collaborative care model; however, evidence on its effectiveness in Asian patients is lacking. Therefore, the primary objective was to evaluate the clinical outcomes of multidisciplinary collaborative care vs physician-centred care in diabetes. The secondary objectives were to evaluate humanistic and economic outcomes among the two types of care. METHODS This 6-month prospective, open-label, parallel-arm, randomized, controlled study was conducted at four outpatient healthcare institutions. High-risk patients aged ≥21 years with uncontrolled type 2 diabetes, polypharmacy and comorbidities were included. Patients with type 1 diabetes or those who were unable to communicate independently were excluded. The control arm received usual care with referrals to nurses and dietitians as needed. The intervention arm (multidisciplinary collaborative care) was followed up with pharmacists regularly, in addition to receiving the usual care. The primary outcomes included HbA1c, systolic blood pressure, low-density lipoprotein and triglycerides. The secondary outcomes included scores from the Problem Areas in Diabetes (PAID) and the Diabetes Treatment Satisfaction Questionnaires (DTSQ), and diabetes-related health service utilization rates and costs. RESULTS AND DISCUSSION Of 411 eligible patients, 214 and 197 patients were randomized into the intervention and control arms, respectively. At 6 months, 141 patients in the intervention arm (65.9%) and 189 patients in the control arm (95.9%) completed the study. Mean HbA1c reduced from 8.6%±1.5% at baseline to 8.1%±1.3% at 6 months in the intervention arm (P=.04), with up to mean HbA1c improvement of 0.8% in patients with greater levels of uncontrolled glycemia. Whereas the mean HbA1c in the control arm remained unchanged (8.5%±1.4%) throughout the 6-month period. Improvements in PAID and DTSQ scores, reduction in physician workload and an average cost savings of US$91.01 per patient were observed in the intervention arm over 6 months. WHAT IS NEW AND CONCLUSIONS The positive clinical, humanistic and economic outcomes highlighted the value of multidisciplinary collaborative care for Asian diabetic patients, thereby supporting the effectiveness of this approach in managing chronic diseases.
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Affiliation(s)
- M Y L Siaw
- Department of Pharmacy, Faculty of Science, National University of Singapore, Singapore, Singapore
| | - Y Ko
- Department of Pharmacy, College of Pharmacy, Taipei Medical University, Taipei, Taiwan.,Research Center for Pharmacoeconomics, College of Pharmacy, Taipei Medical University, Taipei, Taiwan
| | - D C Malone
- College of Pharmacy, University of Arizona, Tucson, AZ, USA
| | - K Y K Tsou
- National Healthcare Group, Singapore, Singapore
| | - Y-J Lew
- National Healthcare Group, Singapore, Singapore
| | - D Foo
- Tan Tock Seng Hospital, Singapore, Singapore
| | - E Tan
- National Healthcare Group, Singapore, Singapore
| | - S C Chan
- National Healthcare Group Pharmacy, Singapore, Singapore
| | - A Chia
- Tan Tock Seng Hospital, Singapore, Singapore
| | - S S Sinaram
- Agency of Integrated Care, Singapore, Singapore
| | - K C Goh
- National Healthcare Group, Singapore, Singapore
| | - J Y-C Lee
- Department of Pharmacy, Faculty of Science, National University of Singapore, Singapore, Singapore
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Tekari A, May RD, Frauchiger DA, Chan SC, Benneker LM, Gantenbein B. The BMP2 variant L51P restores the osteogenic differentiation of human mesenchymal stromal cells in the presence of intervertebral disc cells. Eur Cell Mater 2017; 33:197-210. [PMID: 28266688 DOI: 10.22203/ecm.v033a15] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Spinal fusion is hampered by the presence of remaining intervertebral disc (IVD) tissue and leads to spinal non-union. While the exact mechanism remains unknown, we hypothesise that factors preventing disc ossification, such as antagonists of the bone morphogenetic proteins (BMP), could be responsible for this process. The objective of this study was to investigate spinal non-union using an in vitro human model with a focus on the BMP signalling components and to identify factors contributing to the incomplete and delayed ossification. Human bone marrow-derived mesenchymal stromal cells (MSC) were cocultured with IVD cells in the presence of L51P, a BMP2 variant with osteoinductive potential. The ossification of MSC was evaluated by quantitative reverse transcription polymerase chain reaction (qPCR), alkaline phosphatase (ALP) activity and alizarin red staining. Endogenous expression of major BMP antagonists, namely Gremlin (GREM1), Noggin (NOG) and Chordin (CHRD) was detected in IVD-derived cells, with abundance in nucleus pulposus cells. Osteogenesis of MSC was hindered by IVD cells as shown by reduced alizarin red staining, ALP activity and qPCR. L51P, added to the cocultures, restored mineralisation, blocking the activity of the BMP antagonists secreted by IVD cells. It is possible that the BMP antagonists secreted by IVD cells are responsible for spinal non-unions. The inhibition of BMP antagonists with L51P may result in an efficient and more physiological osteoinduction rather than delivery of exogenous osteogenic factors. Therefore, L51P might represent an attractive therapeutic candidate for bone healing.
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Affiliation(s)
| | | | | | | | | | - B Gantenbein
- Tissue and Organ Mechanobiology, Institute for Surgical Technology and Biomechanics, Stauffacherstrasse 78, 3014 Bern,
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Chan SC, Mohd Amin S, Lee TW. Implementing standard setting into the Conjoint MAFP/FRACGP Part 1 examination - Process and issues. Malays Fam Physician 2016; 11:2-8. [PMID: 28461851 PMCID: PMC5408869] [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: 06/07/2023]
Abstract
BACKGROUND The College of General Practitioners of Malaysia and the Royal Australian College of General Practitioners held the first Conjoint Member of the College of General Practitioners (MCGP)/Fellow of Royal Australian College of General Practitioners (FRACGP) examination in 1982, later renamed the Conjoint MAFP/FRACGP examinations. The examination assesses competency for safe independent general practice and as family medicine specialists in Malaysia. Therefore, a defensible standard set pass mark is imperative to separate the competent from the incompetent. OBJECTIVE This paper discusses the process and issues encountered in implementing standard setting to the Conjoint Part 1 examination. DISCUSSION Critical to success in standard setting were judges' understanding of the process of the modified Angoff method, defining the borderline candidate's characteristics and the composition of judges. These were overcome by repeated hands-on training, provision of detailed guidelines and careful selection of judges. In December 2013, 16 judges successfully standard set the Part 1 Conjoint examinations, with high inter-rater reliability: Cronbach's alpha coefficient 0.926 (Applied Knowledge Test), 0.921 (Key Feature Problems).
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Affiliation(s)
- S C Chan
- FAFPM, FRACGP, Community Based Department, Faculty of Medicine, Universiti Kuala Lumpur Royal College of Medicine Perak, Ipoh, Perak, Malaysia. E-mail: /
| | - S Mohd Amin
- FAFPM, FRACGP, Academy of Family Physicians of Malaysia, Kuala Lumpur, Malaysia. E-mail:
| | - T W Lee
- FAFPM, FRACGP, Klinik TW Lee, Ipoh, Perak, Malaysia. E-mail:
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Wong TCL, She WH, Cheung TT, Chan SC, Lo CM. Case Report of Relay Liver Transplantation With Graft Infected With Hepatitis B Virus. Transplant Proc 2016; 47:2768-70. [PMID: 26680090 DOI: 10.1016/j.transproceed.2015.09.036] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2015] [Accepted: 09/24/2015] [Indexed: 01/01/2023]
Abstract
Reuse of liver graft for transplantation is extremely uncommon. We report the 1st case of reuse of liver graft from a recipient who had hepatitis B virus (HBV) infection, 11 years after the 1st transplantation. Our relay liver transplantation challenged conventional thinking because of late reuse of graft in the presence of HBV infection. Moreover, both the 1st and the 2nd donors were of advanced age. The key questions were whether the liver graft could be reused safely, especially in the setting of HBV infection, and technical concerns during organ procurement and implantation. The absence of HBV replication was confirmed with negative hepatitis B surface antigen and undetectable serum HBV DNA in the 2nd donor. Based on our experience in managing HBV infection after liver transplantation, we were confident that the adequately suppressed HBV infection in the donor would not jeopardize graft function and that the graft would be able to withstand another ischemia-perfusion injury to continue to function well in our recipient.
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Affiliation(s)
- T C L Wong
- Department of Surgery, Queen Mary Hospital, University of Hong Kong, Hong Kong, People's Republic of China
| | - W H She
- Department of Surgery, Queen Mary Hospital, University of Hong Kong, Hong Kong, People's Republic of China
| | - T T Cheung
- Department of Surgery, Queen Mary Hospital, University of Hong Kong, Hong Kong, People's Republic of China
| | - S C Chan
- Department of Surgery, Queen Mary Hospital, University of Hong Kong, Hong Kong, People's Republic of China
| | - C M Lo
- Department of Surgery, Queen Mary Hospital, University of Hong Kong, Hong Kong, People's Republic of China.
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11
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She WH, Chok KSH, Lo RCL, Chan SC, Lo CM. Rare cause of jaundice in a post liver transplant patient. Transpl Infect Dis 2015; 17:579-82. [PMID: 26073470 DOI: 10.1111/tid.12414] [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] [Received: 01/01/2015] [Revised: 03/08/2015] [Accepted: 06/07/2015] [Indexed: 11/28/2022]
Abstract
A hepatitis B virus carrier suffering from acute flare of chronic hepatitis B infection underwent deceased-donor liver transplantation. He was put on the immunosuppressive agent tacrolimus. On routine follow-up, he was found to have abnormal liver function. Computed tomography scan of the abdomen did not show any dilatation of the biliary system. Liver biopsy showed scattered microabscesses, and a microgranuloma was detected. Endoscopic retrograde cholangiography was performed and a biliary anastomotic stricture (BAS) was noted. In addition, the Chinese liver fluke, Clonorchis sinensis, was discovered. Balloon dilatation and stenting were performed. The patient was given a course of praziquantel. His liver function improved and normalized. We present the case of a liver transplant recipient with cholangitis caused by C. sinensis infestation and infection and biliary obstruction resulting from BAS.
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Affiliation(s)
- W H She
- Division of Liver Transplantation, Department of Surgery, Queen Mary Hospital, The University of Hong Kong, Hong Kong, China
| | - K S H Chok
- Division of Liver Transplantation, Department of Surgery, Queen Mary Hospital, The University of Hong Kong, Hong Kong, China
| | - R C L Lo
- Department of Pathology, Queen Mary Hospital, The University of Hong Kong, Hong Kong, China
| | - S C Chan
- Division of Liver Transplantation, Department of Surgery, Queen Mary Hospital, The University of Hong Kong, Hong Kong, China
| | - C M Lo
- Division of Liver Transplantation, Department of Surgery, Queen Mary Hospital, The University of Hong Kong, Hong Kong, China
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Williams PD, Chan SC. Does diabetic status in the ICU predict haemofiltration requirement? The haemofiltration in the ICU and diabetic status (HIDS) study. Anaesth Intensive Care 2014; 42:449-54. [PMID: 24967758 DOI: 10.1177/0310057x1404200404] [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: 11/15/2022]
Abstract
Diabetes is already a major health burden and prevalence is expected to double by 2025. The impact of diabetes and clinical outcomes in the intensive care unit is an evolving area of research. This study seeks to identify whether diabetic status is an independent risk factor for haemofiltration. This is a retrospective cohort study. All unique patients from a seven-year period from 2004 to 2010 at a major intensive care unit in Melbourne, Australia were analysed using multivariate regression to look for an association between diabetic status and haemofiltration. After exclusion criteria there were 7262 patients, 1674 with a history of diabetes (median age of 69, 66.72% male) and 5588 without a history of diabetes (median age 64, 64.13% male). Diabetic status was an independent risk factor (odds ratio 1.401, 95% confidence interval 1.079 to 1.820, P=0.011) for haemofiltration. Further research may identify intensive care unit-based renoprotective measures specifically for patients with diabetes.
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Affiliation(s)
- P D Williams
- Intensive Care Unit, St Vincent's Hospital, Melbourne, Victoria
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13
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Chen CC, Chang MW, Chang CP, Chan SC, Chang WY, Yang CL, Lin MT. A forced running wheel system with a microcontroller that provides high-intensity exercise training in an animal ischemic stroke model. ACTA ACUST UNITED AC 2014; 47:858-68. [PMID: 25140816 PMCID: PMC4181221 DOI: 10.1590/1414-431x20143754] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2013] [Accepted: 05/12/2014] [Indexed: 12/19/2022]
Abstract
We developed a forced non-electric-shock running wheel (FNESRW) system that provides rats with high-intensity exercise training using automatic exercise training patterns that are controlled by a microcontroller. The proposed system successfully makes a breakthrough in the traditional motorized running wheel to allow rats to perform high-intensity training and to enable comparisons with the treadmill at the same exercise intensity without any electric shock. A polyvinyl chloride runway with a rough rubber surface was coated on the periphery of the wheel so as to permit automatic acceleration training, and which allowed the rats to run consistently at high speeds (30 m/min for 1 h). An animal ischemic stroke model was used to validate the proposed system. FNESRW, treadmill, control, and sham groups were studied. The FNESRW and treadmill groups underwent 3 weeks of endurance running training. After 3 weeks, the experiments of middle cerebral artery occlusion, the modified neurological severity score (mNSS), an inclined plane test, and triphenyltetrazolium chloride were performed to evaluate the effectiveness of the proposed platform. The proposed platform showed that enhancement of motor function, mNSS, and infarct volumes was significantly stronger in the FNESRW group than the control group (P<0.05) and similar to the treadmill group. The experimental data demonstrated that the proposed platform can be applied to test the benefit of exercise-preconditioning-induced neuroprotection using the animal stroke model. Additional advantages of the FNESRW system include stand-alone capability, independence of subjective human adjustment, and ease of use.
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Affiliation(s)
- C C Chen
- Department of Electrical Engineering, National Cheng-Kung University, Tainan, Taiwan
| | - M W Chang
- Department of Electrical Engineering, Southern Taiwan University of Science and Technology, Tainan, Taiwan
| | - C P Chang
- Department of Biotechnology, Southern Taiwan University of Science and Technology, Tainan, Taiwan
| | - S C Chan
- Department of Electrical Engineering, National Cheng-Kung University, Tainan, Taiwan
| | - W Y Chang
- Department of Electrical Engineering, National Cheng-Kung University, Tainan, Taiwan
| | - C L Yang
- Department of Electrical Engineering, National Cheng-Kung University, Tainan, Taiwan
| | - M T Lin
- Department of Medical Research, Chi Mei Medical Center, Tainan, Taiwan
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Chan SC, Sharr WW, Chok KS, Chan AC, Lo CM. Media coverage of liver transplant events promotes donations from the deceased. Hong Kong Med J 2013; 19:89-91. [PMID: 23378364] [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: 06/01/2023] Open
Affiliation(s)
- S C Chan
- Department of Surgery, The University of Hong Kong, Pokfulam, Hong Kong.
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Chan GSW, Lam MF, Kwan L, Fung SH, Chan SC, Chan KW. Clinicopathological study of renal biopsies after liver transplantation. Hong Kong Med J 2013; 19:27-32. [PMID: 23378351] [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: 06/01/2023] Open
Abstract
OBJECTIVE To perform a clinicopathological study of patients having renal biopsies after liver transplantation. DESIGN Case series. SETTING; Queen Mary Hospital, Hong Kong. PATIENTS All post-liver transplantation patients who had a renal biopsy in the period from January 2000 to December 2010. RESULTS Eleven renal biopsies were retrieved for review from 10 patients with liver transplantation. The male-to-female ratio was 9:1 (age range, 47-63 years). The median liver transplant-to-renal biopsy interval was 1590 (range, 102-3699) days. The predominant histological changes were interstitial fibrosis and tubular atrophy. Diabetic nephropathy (n=6) and immunoglobulin A nephropathy (n=4) were the commonest glomerulopathies. Only one patient had chronic calcineurin inhibitor nephrotoxicity. With a mean follow-up of 53 months, three patients died 2 to 53 months post-renal biopsy. All surviving patients had chronic renal impairment. Five patients developed end-stage renal failure and four had significant persistent proteinuria. CONCLUSION Renal pathology was variable after liver transplantation; most biopsies showed complex renal lesions, whilst calcineurin inhibitor nephrotoxicity was rare. The recognition of kidney histology attributable to metabolic derangements after liver transplantation is potentially important in the interpretation of renal biopsy specimens and patient management. The renal outlook of this group of patients is guarded.
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Affiliation(s)
- Gavin S W Chan
- Department of Pathology, Queen Mary Hospital, The University of Hong Kong, Hong Kong.
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Chan SC. Views of Malaysian interns and their supervisors on the adequacy of undergraduate clinical skills training. Singapore Med J 2012; 53:196-202. [PMID: 22434295] [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: 05/31/2023]
Abstract
INTRODUCTION This study aimed to determine the views of Malaysian interns and their supervisors on whether undergraduate clinical skills training adequately equipped them for internship and their suggestions for improvement. METHODS Pre-tested questionnaires covering demographic characteristics, the participants' views on clinical skills training (communication, history taking, physical examination, diagnosis, patient management and procedures) and their suggestions for improvement were sent to all interns and their supervisors through the hospital directors. Data compiled was analysed to determine any significant association. RESULTS Out of the 32 hospitals with interns, 22 participated in the study. 521 completed questionnaires (350 interns, 171 supervisors) were analysed. The majority of interns felt that their undergraduate clinical skills training was adequate in all the aspects studied. The majority of supervisors, however, felt that it was grossly inadequate to poor in the areas of communication: breaking bad news (77% supervisors versus 13% interns), dealing with angry patients (75% versus 20%), giving information (59% versus 3%), communicating with patients' families (53% versus 7%); adult resuscitation: intubation (72% versus 23%), defibrillation (77% versus 31%), use of drugs (62% versus 19%); and all aspects of child resuscitation. This was statistically significant (p < 0.05). Suggestions for improvement included more clinical exposure, communication skills workshop and monitoring of logbooks. CONCLUSION This study suggests that there are deficiencies, particularly in communication and resuscitation skills training, in undergraduate clinical skills training. In-depth studies are required to identify ways to improve training.
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Affiliation(s)
- S C Chan
- Primary Care, Universiti Kuala Lumpur - Royal College of Medicine, No. 3, Jalan Greentown, Ipoh 30450, Perak, Malaysia.
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Au WY, Chan SC. Association between glucose 6-phosphate dehydrogenase (G6PD) deficiency and fatal outcome of hepatitis E infection in middle-aged men. Singapore Med J 2012; 53:148-149. [PMID: 22337191] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
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Fan ST, Poon RTP, Yeung C, Lam CM, Lo CM, Yuen WK, Ng KKC, Liu CL, Chan SC. Outcome after partial hepatectomy for hepatocellular cancer within the Milan criteria. Br J Surg 2011; 98:1292-300. [PMID: 21656513 DOI: 10.1002/bjs.7583] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/07/2011] [Indexed: 01/04/2023]
Abstract
BACKGROUND There is a trend to offer liver transplantation to patients with hepatocellular carcinoma (HCC) with tumour status within the Milan criteria but with preserved liver function. This study aimed to evaluate the outcome of such patients following partial hepatectomy as primary treatment. METHODS A retrospective analysis was performed on all adult patients with HCC and tumour status within the Milan criteria undergoing partial hepatectomy at a single centre from 1995 to 2008. Their outcomes were compared with those of similar patients having right-lobe living donor liver transplantation (LDLT) as primary treatment. RESULTS A total of 408 patients with HCC were enrolled. Some 384 patients with a solitary tumour 5 cm or less in diameter had a better 5-year survival rate than 24 patients with oligonodular tumours (2-3 nodules, each 3 cm or less in size) (70·7 versus 46 per cent; P = 0·025). Multivariable analysis identified younger age (65 years or less), lack of postoperative complications, negative resection margin, absent microvascular invasion and non-cirrhotic liver as predictors of favourable overall survival. The 5-year survival rate of 287 younger patients with chronic liver disease and R0 hepatectomy was 72·8 per cent, comparable to that of 81 per cent in 50 similar patients treated by LDLT (P = 0·093). CONCLUSION Partial hepatectomy for patients with HCC and tumour status within the Milan criteria achieved a satisfactory 5-year survival rate, particularly in younger patients with solitary tumours and R0 hepatectomy. Patients with oligonodular tumours have a worse survival and might benefit from liver transplantation.
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Affiliation(s)
- S T Fan
- Department of Surgery, The University of Hong Kong, Queen Mary Hospital, Pokfulam, 102 Pok Fu Lam Road, Hong Kong, China.
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Zhang ZG, Hung YS, Chan SC. Local Polynomial Modeling of Time-Varying Autoregressive Models With Application to Time–Frequency Analysis of Event-Related EEG. IEEE Trans Biomed Eng 2011; 58:557-66. [DOI: 10.1109/tbme.2010.2089686] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Chan SC, Lo CM, Ng KKC, Fan ST. Alleviating the burden of small-for-size graft in right liver living donor liver transplantation through accumulation of experience. Am J Transplant 2010; 10:859-867. [PMID: 20148811 DOI: 10.1111/j.1600-6143.2010.03017.x] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The issue of small-for-size graft (SFSG) containing the middle hepatic vein in right liver living donor liver transplantation from 1996 to 2008 (n = 320) was studied. Characteristics of donors, grafts and recipients were comparable between Era I (first 50 cases) and Era II (next 270 cases) except that the median model for end-stage liver disease (MELD) score was higher in Era I (29 vs. 24; p = 0.024). The median graft to standard liver volume ratio (G/SLV) in Era I was 49.0% (range, 32.8-86.2%), versus 49.3% (range, 28.4-89.4%) in Era II (p = 0.498). Hospital mortality rate, the study endpoint, dropped from 16.0% (8/50) in Era I to 2.2% (6/270) in Era II (p = 0.000). Univariate analysis showed that MELD score (p = 0.002), pretransplant hepatorenal syndrome (p = 0.000) and Era I (p = 0.000) were significant in hospital mortality. Logistic regression analysis showed that only Era I (relative risk 9.758; 95% confidence interval, 2.885-33.002; p = 0.000) was significant. In Era I, G/SLV<40% had a relative risk of 7.8 (95% confidence interval, 1.225-49.677; p = 0.030). The hospital mortality rates for G/SLV<40% were 50% (3/6) and 1.9% (1/52) in Era I and II respectively. In conclusion, through accumulation of experience, SFSG became less important as a factor in hospital mortality.
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Affiliation(s)
- S C Chan
- Department of Surgery, The University of Hong Kong, Queen Mary Hospital, China
| | - C M Lo
- Department of Surgery, The University of Hong Kong, Queen Mary Hospital, China
| | - K K C Ng
- Department of Surgery, The University of Hong Kong, Queen Mary Hospital, China
| | - S T Fan
- Department of Surgery, The University of Hong Kong, Queen Mary Hospital, China
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Chao YK, Chan SC, Chang HK, Liu YH, Wu YC, Hsieh MJ, Tseng CK, Liu HP. Salvage surgery after failed chemoradiotherapy in squamous cell carcinoma of the esophagus. Eur J Surg Oncol 2008; 35:289-94. [PMID: 18396384 DOI: 10.1016/j.ejso.2008.02.014] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2007] [Accepted: 02/27/2008] [Indexed: 10/22/2022] Open
Abstract
AIMS To investigate the survival benefit and preoperative risk factors for hospital mortality of salvage surgery in esophageal cancer patients who had locoregional residual/recurrent tumor after definitive chemoradiotherapy. METHODS We retrospectively reviewed the esophageal cancer patients who presented at our hospital from 1997 to 2004. Forty-seven patients who had squamous cell cancer and developed locoregional recurrent/persistent disease after primary definitive chemoradiotherapy were elected. Twenty-seven of them received salvage esophagectomy (group 1) and the other 20 underwent non-operative treatment only (group 2). In order to assess the surgery-related mobility and mortality in group 1, 191 patients who received neoadjuvant chemoradiotherapy followed by operation during the same time period were also enrolled (group 3). RESULTS The 5-year overall survival of group 1 patients was 25.4%. In contrast, all of the patients in the group 2 died within 16.7 months. The difference was statistically significant (p=0.0029). In comparison with group 3, group 1 patients had significantly more surgery-related complications and hospital mortality. In univariate analysis for preoperative risk factors, a low albumin or hemoglobulin level was associated with high hospital mortality in group 1 (p=0.004 and 0.003, respectively). After multivariate analysis, only the low albumin level remained borderline significance. As for disease specific survival after salvage surgery, R0 resection was the only independent prognosticator (p=0.049). CONCLUSION Salvage surgery provides survival benefit in esophageal cancer patients with locoregional persistent or recurrent disease after primary definitive chemoradiotherapy. Preoperative albumin and hemoglobulin levels are associated with hospital mortality and may aid in selecting suitable patient for salvage surgery.
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Affiliation(s)
- Y K Chao
- Department of Surgery, Chang Gung Memorial Hospital, Chang Gung University, Taoyuan, Taiwan
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Chan SC, Lee TW, Teoh LC, Abdullah ZC, Xavier G, Sim CK, Ng AC, Ong ICH, Begum R, Leong CC. Audit on cardiovascular disease preventive care in general practice. Singapore Med J 2008; 49:311-315. [PMID: 18418523] [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: 05/26/2023]
Abstract
INTRODUCTION Cardiovascular disease is a major cause of morbidity and mortality. Primary care doctors as general practitioners (GPs) play a central role in prevention, as they are in contact with a large number of patients in the community through provision of first contact, comprehensive and continuing care. This study aims to assess the adequacy of cardiovascular disease preventive care in general practice through a medical audit. METHODS Nine GPs in Malaysia did a retrospective audit on the records of patients, aged 45 years and above, who attended the clinics in June 2005. The adequacy of cardiovascular disease preventive care was assessed using agreed criteria and standards. RESULTS Standards achieved included blood pressure recording (92.4 percent), blood sugar screening (72.7 percent) and attaining the latest blood pressure of equal or less than 140/90 mmHg in hypertensive patients (71.3 percent). Achieved standards ranged from 11.1 percent to 66.7 percent in the maintenance of hypertension and diabetic registries, recording of smoking status, height and weight, screening of lipid profile and attaining target blood sugar levels in diabetics. CONCLUSIONS In the nine general practice clinics audited, targets were achieved in three out of ten indicators of cardiovascular preventive care. There were vast differences among individual clinics.
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Affiliation(s)
- S C Chan
- Department of Primary Care, Universiti Kuala Lumpur Royal College of Medicine Perak, 3 Jalan Greentown, Ipoh 30450, Malaysia.
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Zaid ZA, Chan SC, Ho JJ. Emotional disorders among medical students in a Malaysian private medical school. Singapore Med J 2007; 48:895-9. [PMID: 17909672] [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: 05/17/2023]
Abstract
INTRODUCTION A study was done between December 2005 and January 2006 to determine the prevalence of emotional disorders among medical students in a private medical school in Ipoh, Perak, Malaysia and to determine the demographical characteristics, contributing factors and the key person consulted for emotional problems. METHODS Medical students in the private medical school completed the 12-item English version of the General Health Questionnaire (GHQ-12) and a demographical questionnaire. A cut-off point of 3/4 for the GHQ was used to determine negative and positive scores for emotional disorders. RESULTS Out of 292 medical students, 86.6 percent completed the questionnaires. A total of 117 students (46.2 percent) were found to have emotional disorders. There was no significant association of ethnicity, gender, age group, number of examinations sat, examination performances, past medical conditions and relationships with parents, siblings, course-mates and lecturers with positive GHQ scores. A significant association, however, was found between positive GHQ scores for emotional disorders and the year of study, pressure faced due to examinations, and not having a love relationship. 39 percent of the students stated friends as their main preference for consultation of any emotional problem. CONCLUSION The prevalence of emotional disorders among medical students was high. Further studies and diagnostic measures are recommended, including a more systematic screening and counselling programme by the medical school for early diagnosis and treatment to prevent complications.
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Affiliation(s)
- Z A Zaid
- Universiti Kuala Lumpur, Royal College of Medicine Perak, 3 Jalan Greentown, Ipoh 30450, Perak, Malaysia
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Lo CM, Fan ST, Liu CL, Chan SC, Ng IOL, Wong J. Living donor versus deceased donor liver transplantation for early irresectable hepatocellular carcinoma. Br J Surg 2007; 94:78-86. [PMID: 17016793 DOI: 10.1002/bjs.5528] [Citation(s) in RCA: 185] [Impact Index Per Article: 10.9] [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: 12/11/2022]
Abstract
BACKGROUND Hypothetical studies that favour living donor liver transplantation (LDLT) for early hepatocellular carcinoma (HCC) assumed a comparable outcome after LDLT and deceased donor liver transplantation (DDLT). The aim of this study was to compare the outcome after LDLT with that after DDLT, and to identify factors that might account for any differences. METHODS The study included 60 patients who met the radiological Milan or University of California at San Francisco (UCSF) criteria and underwent LDLT (43 patients) or DDLT (17). RESULTS The LDLT group had fewer incidental tumours and a lower rate of pretransplant transarterial chemoembolization but a higher rate of salvage transplantation. Waiting time was shorter and graft weight to standard liver weight (GW : SLW) ratio was lower in this group. The perioperative course, and histopathological tumour size, number, grade and stage were comparable. Median follow-up was 33 (range 4-120) months. The cumulative 5-year recurrence rate was 29 per cent in the LDLT group and 0 per cent in the DDLT group (P = 0.029). A GW : SLW ratio of 0.6 or less, salvage transplantation, three or more tumour nodules, microscopic vascular invasion, and pathological stage beyond the Milan or UCSF criteria were significant confounding risk factors. Multivariable analysis identified salvage transplantation (relative risk 5.16 (95 per cent confidence interval (c.i.) 1.48 to 18.02); P = 0.010) and pathological stage beyond the UCSF criteria (relative risk 4.10 (95 per cent c.i. 1.02 to 16.48); P = 0.047) as independent predictors of recurrence. CONCLUSION Despite standard radiological selection criteria based on number and size, patients who underwent LDLT for HCC had more recurrence because of selection bias for other clinical characteristics.
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Affiliation(s)
- C M Lo
- Department of Surgery, The University of Hong Kong, Queen Mary Hospital, 102 Pokfulam Road, Hong Kong, China.
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Mokhtar N, Chan SC. Use of complementary medicine amongst asthmatic patients in primary care. Med J Malaysia 2006; 61:125-7. [PMID: 16708752] [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: 05/09/2023]
Abstract
Complementary Medicine (CM) usage amongst asthmatic patients was studied. Eighty-eight patients, selected by systematic random sampling in two public polyclinics in April/May 2004, were interviewed. They completed a structured pre-tested questionnaire. Forty-one percent were using CM, majority (64%) together with conventional therapy. Eighty-one percent did not inform their physicians of their CM usage. More Malays were using CM which included nutritional supplements, herbs, yoga, homoeopathy, reflexology and massage.
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Affiliation(s)
- N Mokhtar
- Department of Primary Care & Public Health, Royal College of Medicine Perak, 3 Jalan Greentown, 30450 Ipoh, Perak
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Chan SC, Chandramani T, Chen TY, Chong KN, Harbaksh S, Lee TW, Lin HG, Sheikh A, Tan CW, Teoh LC. Audit of hypertension in general practice. Med J Malaysia 2005; 60:475-82. [PMID: 16570710] [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: 05/08/2023]
Abstract
An audit of hypertension management was done in October 2004 in nine general practice (GP) clinics. Two structure, ten process and two outcome indicators were assessed. Results showed that targets were achieved in only four indicators, i.e., weight recording (89%), BP monitoring (85.8%), follow-up interval not exceeding 6 months (87.9%) and mean diastolic BP (73.9%). The other indicators (hypertension registry, reminder mechanisms for defaulters, recording of smoking, height, fundoscopy, monitoring of lipid profile, blood sugar, ECG, renal function and achievement of target mean systolic pressure) showed adequacy percentages varying from 22.1 to 68.7. Out of the 1260 patients assessed, 743 (59%) achieved a mean BP < or = 140/90 (or < or = 130/80 mmHg with diabetes mellitus / renal insufficiency) in the last 3 recorded readings. There was a vast difference between individual clinics. Reasons for not achieving targets were discussed and remedial measures for implementation were recommended.
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Affiliation(s)
- S C Chan
- Department of Primary Care and Public Health, Royal College of Medicine Perak, Ipoh
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Mahfudz AS, Chan SC. Use of complementary medicine amongst hypertensive patients in a public primary care clinic in Ipoh. Med J Malaysia 2005; 60:454-9. [PMID: 16570707] [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: 05/08/2023]
Abstract
The use and reasons for use of Complementary Medicine (CM) amongst hypertensive patients attending the Hypertension/ Diabetes/ Asthma Clinic in Greentown Health Clinic, Ipoh was assessed. One hundred and twenty patients were selected by systematic random sampling (1:5) over a 2-week period commencing 26/04/04. Data was obtained from interviews, questionnaires and medical records. Twenty seven percent were on CM. Most commonly used CM was herbal medicine. Majority of those using CM for BP control were Malays. The Chinese and Indians were using CM mainly for other health problems. Ninety six percent were using both CM and conventional therapy concurrently. Therefore doctors should enquire about CM usage during patient assessment to prevent possible drug interactions.
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Affiliation(s)
- A S Mahfudz
- Department of Primary Care & Public Health, Royal College of Medicine Perak, 3 Jalan Greentown, 30450 Ipoh, Perak
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Abstract
Hepatic lymphangioma is an extremely rare benign neoplasm that is usually associated with lymphangiomas of other viscera. We report a patient with huge, solitary hepatic lymphangioma involving only the liver. The clinical features and computed tomography findings of this case are described.
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Affiliation(s)
- S C Chan
- Department of Diagnostic Radiology, Chang Gung Memorial Hospital at Keelung, Taiwan
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Chan SC. Primary care--directions we should be taking. Med J Malaysia 2005; 60:127-9. [PMID: 16114150] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
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Huang PC, Cheung YC, Chan SC, Wong HF, Wan YL. The clinical significance of gas-containing liver abscesses converting from total gas content to gas and fluid content: a case report. Int J Clin Pract 2005:37-9. [PMID: 15875617 DOI: 10.1111/j.1368-504x.2005.00335.x] [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] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
The first case of gas-containing liver abscesses converting from total gas content to gas and fluid content is reported, and the clinical significance of such a conversion is emphasised. A 58-year-old diabetic woman suffered from fever and chill due to totally gas-containing liver abscesses shown by computerised tomography (CT). The patient did not recover despite ultrasound-guided aspiration of the abscess. CT carried out 2 weeks later revealed that the initial totally gas-containing liver abscesses converted to ones with gas and fluid content. The patient recovered after CT-guided drainage of the abscesses.
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Affiliation(s)
- P C Huang
- First Department of Diagnostic Radiology, Chang Gung Memorial Hospital at Linkou, School of Medicine and Medical Technology, Chang Gung University, Taoyuan, Taiwan
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Chan SC. Audits in general practice by medical students. Med J Malaysia 2004; 59:609-16. [PMID: 15889563] [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: 05/02/2023]
Abstract
This paper reports the implementation, findings and feedback of the audit project of the general practice (GP) module carried out in the fifth year of the MBChB (Sheffield) twinning programme with the Perak College of Medicine. After training, each student with his/her GP tutor planned and conducted the audit. All 28 students (year 2002) satisfactorily completed their audit projects. Fifty percent did an audit of hypertension, 36% on diabetes, 7% on asthma and one each (3.5%) on upper respiratory tract infection and client satisfaction. It was the GP tutors first experience at audit in their clinics. The majority of indicators of care audited did not meet the set target standards.
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Affiliation(s)
- S C Chan
- Department of Primary Care and Public Health, Perak College of Medicine, 3 Jalan Greentown, 30450 Ipoh, Perak
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Abstract
Combined hepatocellular-cholangiocarcinoma (HCC-CC) is a rare primary liver tumour. We report a carrier of both HBV and HCV presenting with intermittent abdominal pain, fever, chillness and elevated á-fetoprotein (AFP) of 1197 ng/ml. Computed tomography showed an irregular hypodense mass in the left lateral segment of the liver with vague contrast enhancement and multiple regional lymphadenopathy. Hepatic angiogram showed that the mass was hypovascular and the left portal vein was occluded with a tapered end. Percutaneous ultrasound-guided core needle biopsy of the liver yielded HCC-CC. We suggest that HCC-CC should be considered in hypovascular liver tumours with striking elevation of serum AFP and multiple regional lymphadenopathy.
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Affiliation(s)
- C H Toh
- Department of Diagnostic Radiology, Chang Gung Memorial Hospital, Keelung, Taiwan, ROC
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Abstract
Oral prednisone (1)might be a convenient, inexpensive alternative to IV methylprednisolone (IVMP) if the bioequivalent dose was known. We compared the total amount of steroid absorbed after 1250 mg oral prednisone vs 1 gram IVMP in 16 patients with multiple sclerosis (MS). At 24 hours, the mean area under the concentration-time curve (AUC), the main component of bioavailability, did not differ between groups (p = 0.122). This suggests that the amount of absorbed corticosteroid is similar after either steroid at these doses.
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Affiliation(s)
- S A Morrow
- Department of Clinical Neurosciences, University of Western Ontario, London, Ontario, Canada
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Lee TW, Chan SC, Chua WT, Harbinder K, Khoo YL, Ow Yeang YL, Sethuraman K, Teoh LC. Audit of diabetes mellitus in general practice. Med J Malaysia 2004; 59:317-22. [PMID: 15727376] [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: 05/01/2023]
Abstract
An audit on diabetic management was done in seven Perak general practice (GP) clinics in December 2001. The results showed inadequacies in nine out of eleven criteria assessed. Remedial measures were implemented. A second audit in March 2003, at the completion of the audit cycle, showed improvements in all the criteria used. All clinics established a diabetic register compared to 28.6% in the first audit and 57.1% of the clinics set up a reminder mechanism compared to 0% in the first audit. In the process of care, recording of weight, height, blood pressure; feet examination, fundoscopy, blood sugar monitoring and urine for albumin improved at the end of the audit cycle. In the only outcome criteria, the blood sugar control improved from 21.8% to 31.3%.
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Affiliation(s)
- T W Lee
- Department of Primary Care and Public Health, Perak College of Medicine, No. 3, Jalan Greentown, 30450 Ipoh, Perak
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Chan SC, Ko SF, Ng SH, Cheung YC, Chang JTC, Liao CT, Wang HM, Lui KW. Fluoroscopically guided percutaneous gastrostomy with modified gastropexy and a large-bore balloon-retained catheter in patients with head and neck tumors. Acta Radiol 2004; 45:130-5. [PMID: 15191094 DOI: 10.1080/02841850410003707] [Citation(s) in RCA: 7] [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] [Indexed: 12/24/2022]
Abstract
PURPOSE To report on fluoroscopically guided percutaneous gastrostomy (FPG) using a modified gastropexy technique with the insertion of a large-bore balloon-retained gastrostomy catheter in patients with head and neck tumors. MATERIAL AND METHODS Thirty-four patients with head and neck tumors underwent a modified gastropexy with two T-fasteners followed by the insertion of a 14-F ballooon-retained catheter through a peel-away introducer. The success rate and the complications of the procedures were evaluated at 14 days, 30 days, and 60 days. The complications were classified as: major complications that necessitated intensive and/or surgical treatment; minor complications that could be treated conservatively; and tube-related complications manageable by tube exchange. RESULTS FPG was technically successful in all cases. There were no major complications, two minor complications where superficial stoma infection was controlled by antibiotics, three minor tube-related complications, all three easily managed by catheter replacement via the original tract. CONCLUSION FPG with insertion of a large-bore balloon-retained catheter using a modified gastropexy technique is a safe and effective method that creates a feeding access for patients with head and neck tumors and esophageal obstruction. Minor complications can be managed conservatively. FPG may be a good alternative to surgical or percutaneous endoscopic gastrostomy.
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Affiliation(s)
- S C Chan
- Department of Diagnostic Radiology, Chang Gung Memorial Hospital, Lin-Kou Medical Center and Keelung Hospital, Taiwan.
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Ismail IA, Chan SC. Knowledge and practice of complementary medicine amongst public primary care clinic doctors in Kinta district, Perak. Med J Malaysia 2004; 59:4-10. [PMID: 15535328] [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: 05/01/2023]
Abstract
The knowledge and practice of doctors (n=40) towards complementary medicine (CM) in 16 health clinics in the Kinta District were assessed by questionnaire. Thirty-four (85%) responded. More than half felt that acupuncture (73.50), homeopathy (59%) and herbal medicine (59%) were occasionally harmful. Forty-four percent felt manipulative therapy was frequently harmful. Relaxation technique (79%) and nutritional therapy (44%) were considered most frequently useful. 59% used some form of CM. There were no significant differences found in usage rates by gender, age group and exposure to CM during undergraduate training. Sixty-seven percent had encouraged patients to seek CM. Seventy-three percent perceived an increasing demand for CM. Eighty-eight percent were in favour of a hospital based CM referral center. Only 6% were trained in CM.
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Abstract
Myomas are uncommon in adolescence and very rarely occur outside the uterus. Torsion of a paraovarian myoma in an 18-year-old woman was managed laparoscopically. Awareness of the condition and high index of suspicion are keys to early diagnosis and prompt intervention.
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Affiliation(s)
- S C Chan
- Department of Obstetrics and Gynaecology, Prince of Wales Hospital, Chinese University of Hong Kong, Hong Kong
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Lin CY, Lee SC, Lin CC, Chan SC, Lee CT. Isolated fatal renal mucormycosis in a patient with chronic obstructive pulmonary disease and tuberculosis. Int J Clin Pract 2003; 57:916-8. [PMID: 14712898] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 04/05/2023] Open
Abstract
Renal mucormyosis is a rare entity and normally diagnosed at postmortem. Isolated cases diagnosed antemortem are even rarer and only a few cases have been reported. The disease is associated with a high mortality rate, especially in patients with underlying disease. Clinical presentation is non-specific and includes flank pain, fever and pyuria with or without haematuria. Identifying fungal hyphae microscopically is essential for diagnosis. We present a rare isolated fatal case of renal mucormycosis in a 77-year-old man with chronic obstructive pulmonary disease (COPD) and old tuberculosis (TB) who had been diagnosed after a right nephrectomy. We believe early diagnosis and appropriate treatment for fungal infection, together with the predisposing underlying disease, is crucial for survival.
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Affiliation(s)
- C Y Lin
- Department of Pathology, Chang Gung Memorial Hospital, Keelung, Taiwan, Republic of China
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Remli R, Chan SC. Use of complementary medicine amongst diabetic patients in a public primary care clinic in Ipoh. Med J Malaysia 2003; 58:688-93. [PMID: 15190655] [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: 04/29/2023]
Abstract
The use of Complementary Medicine (CM) amongst diabetic patients attending the Diabetes/Hypertension, Clinic. Out Patient Department, Ipoh Hospital was studied: Forty-three patients were selected by systematic random sampling (1:5) over a one-week period starting 5/12/01. Data were collected by patient interview, from medical records and through a questionnaire. 56% were using CM together with conventional therapy. Most commonly used were herbal therapy, homeopathy and reflexology. The majority took CM daily with a mean duration of 7 years. Over half had subjective relief of pain with increased energy. Patients on CM or conventional therapy both showed poorly controlled FBS levels. There is a need to assess the effect of these therapies on diabetic outcome.
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Chan SC, Ng SH, Lee KF, Hao SP, Cheung YC, Wan YL. Submandibular Castleman's disease. Int J Clin Pract 2002; 56:314-5. [PMID: 12074219] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/25/2023] Open
Abstract
Castleman's disease is a rare benign lymphoid tumour of unknown aetiology, which usually appears as a solitary mediastinal mass. We report an unusual case of Castleman's disease, an asymptomatic submandibular mass in the lower jaw, and we discuss the computed tomography appearance.
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Affiliation(s)
- S C Chan
- Department of Diagnostic Radiology, Chang Gung Memorial Hospital, Keelung, Taiwan
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Chan SC, Chan SK, Kwok IC, Yu HC. The speech and language rehabilitation program for pediatric cochlear implantees in Hong Kong. Adv Otorhinolaryngol 2002; 57:247-9. [PMID: 11892159 DOI: 10.1159/000059151] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/24/2023]
Affiliation(s)
- S C Chan
- Department of ENT, Queen Elizabeth Hospital, Hong Kong.
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Fong WC, Chan SC, Nallanathan A, Ho KL. Integer lapped transforms and their applications to image coding. IEEE Trans Image Process 2002; 11:1152-1159. [PMID: 18249687 DOI: 10.1109/tip.2002.804266] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
This paper proposes new integer approximations of the lapped transforms, called the integer lapped transforms (ILT), and studies their applications to image coding. The ILT are derived from a set of orthogonal sinusoidal transforms having short integer coefficients, which can be implemented with simple integer arithmetic. By employing the same scaling constants in these integer sinusoidal transforms, integer versions of the lapped orthogonal transform (LOT), the lapped biorthogonal transform (LBT), and the hierarchical lapped biorthogonal transform (HLBT) are developed. The ILTs with 5-b integer coefficients are found to have similar coding gain (within 0.06 dB) and image coding performances as their real-valued counterparts. Furthermore, by representing these integer coefficients as sum of powers-of-two coefficients (SOPOT), multiplier-less lapped transforms with very low implementation complexity are obtained. In particular, the implementation of the eight-channel multiplier-less integer LOT (ILOT), LBT (ILBT), and HLBT (IHLBT) require 90 additions and 44 shifts, 98 additions and 59 shifts, and 70 additions and 38 shifts, respectively.
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Affiliation(s)
- W C Fong
- Dept. of Electr. and Electron. Eng., Hong Kong Univ., Hong Kong
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Tzeng BC, Chan SC, Chan MC, Che CM, Cheung KK, Peng SM. Palladium(II) and platinum(II) analogues of luminescent diimine Triangulo complexes supported by triply bridging sulfide ligands: structural and spectroscopic comparisons. Inorg Chem 2001; 40:6699-704. [PMID: 11735481 DOI: 10.1021/ic010891r] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.7] [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
Reaction of [M(L-L)Cl(2)] [M = Pd, Pt; L-L = 4,4'-di-tert-butyl-2,2'-bipyridine ((t)Bu(2)bpy), 4,4'-dimethylcarboxylate-2,2'-bipyridine ((CO(2)Me)(2)bpy), bis(diphenylphosphino)methane (dppm)] with Na(2)S in refluxing methanol afforded [M(3)((t)Bu(2)bpy)(3)(mu(3)-S)(2)](2+) [M = Pd (1a), Pt (2a)], [M(3)((CO(2)Me)(2)bpy)(3)(mu(3)-S)(2)](2+) [M = Pd (1b), Pt (2b)], and [Pt(3)(dppm)(3)(mu(3)-S)(2)](2+) (3) as perchlorate salts. X-ray crystal analysis revealed that 1a, 1b, 2a, and 3 have triangular M(3)S(2) core structures. The three metal atoms in 1a, 2a, and 3 form virtual equilateral triangles with intramolecular Pd-Pd and Pt-Pt separations of 3.027(1)-3.065(1) and 3.104(1)-3.154(1) A, respectively. An isosceles triangle of Pd(3) atoms is observed in the molecular structure of 1b. The (1)MLCT absorption of 2a and 2b appears at 415 and 448 nm, respectively, in dichloromethane and is significantly red-shifted from the lowest energy absorption band of the Pd(3) analogues. Complex 1a exhibits weak photoluminescence in the solid state at 77 and 298 K (uncorrected lambda(max) 760 and 730 nm, respectively) while the 77 K solid-state emission of 1b (uncorrected lambda(max) 760 nm) is also weak. At 77 K, complexes 2a, 2b, and 3 display broad unstructured emissions at lambda(max) 616-630 nm in the solid state. Ligand-field excited states are tentatively assigned for these emissions.
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Affiliation(s)
- B C Tzeng
- Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong SAR, China
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Leung KW, Liaw YC, Chan SC, Lo HY, Musayev FN, Chen JZ, Fang HJ, Chen HM. Significance of local electrostatic interactions in staphylococcal nuclease studied by site-directed mutagenesis. J Biol Chem 2001; 276:46039-45. [PMID: 11598114 DOI: 10.1074/jbc.m106620200] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In this paper, we show that amino acids Glu(73) and Asp(77) of staphylococcal nuclease cooperate unequally with Glu(75) to stabilize its structure located between the C-terminal helix and beta-barrel of the protein. Amino acid substitutions E73G and D77G cause losses of the catalytic efficiency of 24 and 16% and cause thermal stability losses of 22 and 26%, respectively, in comparison with the wild type (WT) protein. However, these changes do not significantly change global and local secondary structures, based on measurements of fluorescence and CD(222 nm). Furthermore, x-ray diffraction analysis of the E75G protein shows that the overall structure of mutant and WT proteins is similar. However, this mutation does cause a loss of essential hydrogen bonding and charge interactions between Glu(75) and Lys(9), Tyr(93), and His(121). In experiments using double point mutations, E73G/D77G, E73G/E75G, and E75G/D77G, significant changes are seen in all mutants in comparison with WT protein as measured by fluorescence and CD spectroscopy. The losses of thermal stability are 47, 59, and 58%, for E73G/D77G, E73G/E75G, and E75G/D77G, respectively. The triple mutant, E73G/E75G/D77G, results in fluorescence intensity and CD(222 nm) close to those of the denatured state and in a thermal stability loss of 65% relative to the WT protein. Based on these results, we propose a model in which significant electrostatic interactions result in the formation of a locally stable structure in staphylococcal nuclease.
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Affiliation(s)
- K W Leung
- Department of Biochemistry, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong
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Abstract
Acute tonsillectomy has been advocated for severe infectious mononucleosis (IM) pharyngotonsillitis with upper airway obstruction (UAO) and not responding to corticosteroids. This paper reviews and rationalizes our management. A five-year chart review was carried out with a follow-up telephone survey. There were 36 admissions. Nine had UAO of whom 89 per cent (eight of nine patients) had a tonsillectomy. The diagnosis of UAO was not standardized. Twenty-seven patients did not have UAO and only a small proportion of these patients, 16 per cent (four of 25) went on to have an elective tonsillectomy. Corticosteroids made no significant difference to the tonsillectomy rate. UAO appears to identify patients with more severe disease who are likely to suffer recurrent tonsillitis. Acute tonsillectomy is an appropriate treatment option for this subgroup. The diagnosis of significant IM UAO is not defined and a schema is proposed. Recurrent tonsillitis is an uncommon sequela of severe IM pharyngotonsillitis without UAO.
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Affiliation(s)
- S C Chan
- Department of Otolaryngology-Head and Neck Surgery, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand
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Kwok PC, Wong KM, Ngan RK, Chan SC, Wong WK, Wong KY, Wong AK, Chau KF, Li CS. Prevention of recurrent central venous stenosis using endovascular irradiation following stent placement in hemodialysis patients. Cardiovasc Intervent Radiol 2001; 24:400-6. [PMID: 11907747 DOI: 10.1007/s00270-001-0034-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [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: 10/28/2022]
Abstract
This study was done to evaluate the outcome after brachytherapy (BT) given to prevent restenosis after stent insertion for central venous stenosis in patients with ipsilateral hemodialysis arteriovenous fistulas (AVF). Angioplasty and stenting were performed on 9 primary central venous stenoses in 8 patients with AVF followed by BT, delivering Iridium-192 radiation using an afterloading technique. BT was also administered to three patients with five recurrent stenoses at the stent margins. There was no residual stenosis after angioplasty and stenting. Venographic follow-up (77-644 days, mean 272 days) showed no restenosis in seven primary stenoses. New strictures (45%-100%) developed at the stent margin in six veins (five patients). Angioplasty or stenting was performed for five margin stenoses in three patients, followed by a second BT. Residual stenosis before BT was 0-30%. In our venographic follow-up (140-329 days, mean 215 days), three restenoses occurred (35%-100%). All progressed to complete occlusion on later venographic follow-up irrespective of whether BT was given to the stent margin or not. The mean primary and assisted primary patency of the central veins were 359 days and 639 days, respectively. Endovascular irradiation with a noncentering source does not prolong the patency after angioplasty and stenting of central venous stenosis in hemodialysis patients.
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Affiliation(s)
- P C Kwok
- Department of Radiology and Imaging, Queen Elizabeth Hospital, Kowloon, Hong Kong
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Chan SC, Chan MC, Wang Y, Che CM, Cheung KK, Zhu N. Organic light-emitting materials based on bis(arylacetylide)platinum(II) complexes bearing substituted bipyridine and phenanthroline ligands: photo- and electroluminescence from 3MLCT excited states. Chemistry 2001; 7:4180-90. [PMID: 11686597 DOI: 10.1002/1521-3765(20011001)7:19<4180::aid-chem4180>3.0.co;2-9] [Citation(s) in RCA: 325] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
We present the synthesis and photophysical and electroluminescent properties for a series of platinum(II) alpha-diimine bis(arylacetylide) complexes. The molecular structures of five derivatives have been elucidated by X-ray crystallography. Intermolecular pi-pi interactions (between aromatic diimine and phenylacetylide moieties) are apparent in the crystal lattices of two of these. All bis(phenylacetylide) derivatives exhibit intense triplet metal-to-ligand charge transfer (MLCT) photoluminescence in the solid state and in fluid solutions at room temperature. The impact of different solvents, substituents on the diimine ligands, and complex concentrations upon their emissive behavior have been examined and demonstrates that their emission energies can be systematically modified. Application of the 3MLCT excited state of the [Pt(alpha-diimine) (C(triple bond)CPh)2] materials in single- and double-layer organic light-emitting devices are described. The bis(butadiynyl) complex [Pt(4,4'-dtbpy)(C(triple bond)C-C(triple bond)CPh)2] (dtbpy = 4,4'-di-tert-butyl-2,2'-bipyridine) displays strong solid-state and solution phosphorescence at 77 and 298 K; the associated excited state is proposed to arise from both acetylenic 3pi pi*(C(triple bond)C-C(triple bond)CPh) and 3MLCT [Pt --> pi*(diimine)] transitions.
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Affiliation(s)
- S C Chan
- Department of Chemistry, The University of Hong Kong, Hong Kong SAR, China
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Yung WH, Leung PS, Ng SS, Zhang J, Chan SC, Chow BK. Secretin facilitates GABA transmission in the cerebellum. J Neurosci 2001; 21:7063-8. [PMID: 11549716 PMCID: PMC6763004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/21/2023] Open
Abstract
Secretin was the first hormone discovered in human history, and yet, its function as a neuropeptide has been overlooked in the past. The recent discovery of the potential use of secretin in treating autistic patients, together with the conflicting reports on its effectiveness, urges an in-depth investigation of this issue. We show here that in the rat cerebellar cortex, mRNAs encoding secretin are localized in the Purkinje cells, whereas those of its receptor are found in both Purkinje cells and GABAergic interneurons. Immunoreactivity for secretin is localized in the soma and dendrites of Purkinje cells. In addition, secretin facilitates evoked, spontaneous, and miniature IPSCs recorded from Purkinje cells. We propose that secretin is released from the somatodendritic region of Purkinje cells and serves as a retrograde messenger modulating GABAergic afferent activity.
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Affiliation(s)
- W H Yung
- Department of Physiology, The Chinese University of Hong Kong, Shatin, Hong Kong
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Kwok PC, Chung TK, Chong LC, Chan SC, Wong WK, Chan MK, Chu WS. Neurologic injury after endovascular stent-graft and bilateral internal iliac artery embolization for infrarenal abdominal aortic aneurysm. J Vasc Interv Radiol 2001; 12:761-3. [PMID: 11389230 DOI: 10.1016/s1051-0443(07)61450-x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The authors report a rare neurologic complication after the implantation of a bifurcated stent-graft for abdominal aortic aneurysm. The stent-graft was extended to both external iliac arteries after embolization of both internal iliac arteries. The patient subsequently had weakness and numbness of both lower limbs with bowel and bladder incontinence. He probably had ischemic injury to the nerve roots or the lumbosacral plexus, which was related to extensive occlusion of their supplying arteries. The mechanism of spinal cord and neurologic ischemia after aortic stent-graft implantation is discussed.
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Affiliation(s)
- P C Kwok
- Department of Radiology and Imaging, Queen Elizabeth Hospital, 30 Gascoigne Road, Kowloon, Hong Kong.
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