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Morgan T, Wiles J, Morgan K, Williams L, Black S, Koh A, Fanueli E, Moeke-Maxwell T, Xu J, Goodwin H, Gott M. Older people's views on loneliness during COVID-19 lockdowns. Aging Ment Health 2024; 28:142-150. [PMID: 37178140 DOI: 10.1080/13607863.2023.2211549] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Accepted: 04/29/2023] [Indexed: 05/15/2023]
Abstract
BACKGROUND AND OBJECTIVES There have been growing concerns that social distancing and stay-at-home mandates have exacerbated loneliness for older people. Empirical evidence about older people's experiences of loneliness and COVID-19 have quantified this phenomena without considering how older people themselves define and understand loneliness. This paper explores how older New Zealanders conceptualized and experienced loneliness under 'lockdown' stay-at-home measures. METHODS This multi-methods qualitative study combines data from letters (n = 870) and interviews (n = 44) collected from 914 people aged over 60 and living in Aotearoa, New Zealand during the COVID-19 pandemic. We conducted a reflexive thematic analysis to conceptualise this data. FINDINGS We identify three interconnected ways in which older people conceptualised and experienced loneliness: (1) feeling disconnected relating to lack of emotional closeness to another often resulting from being physically separated from others and not being able to touch; (2) feeling imprisoned relating to separation from preferred identities and activities and was frequently associated with boredom and frustration; and (3) feeling neglected which often related to feeling let down by generalised and idealised forms of support, such as one's neighbourhood and health care system. DISCUSSION Older New Zealanders experienced lockdown loneliness in three interconnected ways rather than as a stable and homogenous experience. Māori, Pacific, Asian and New Zealand European older people often discussed loneliness in different ways; attesting to loneliness being a culturally-mediated concept shaped by expectations around desirable social interaction. We conclude the paper with implications for research and policy.
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Affiliation(s)
- Tessa Morgan
- Department of Public Health and Primary Care, University of Cambridge, Cambridge, United Kingdom
| | - Janine Wiles
- School of Population Health, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
| | - Kathryn Morgan
- School of Nursing, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
| | - Lisa Williams
- School of Nursing, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
| | - Stella Black
- School of Nursing, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
| | - Anne Koh
- School of Nursing, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
| | - Elizabeth Fanueli
- School of Population Health, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
| | - Tess Moeke-Maxwell
- School of Nursing, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
| | - Jing Xu
- School of Nursing, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
| | - Hetty Goodwin
- School of Nursing, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
| | - Merryn Gott
- School of Nursing, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
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Koh A, Parks RM, Courtney A, Leff DR. Mastitis And Mammary abscess Management Audit (MAMMA). Br J Surg 2021; 108:e286-e287. [PMID: 34370817 PMCID: PMC10364893 DOI: 10.1093/bjs/znab155] [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] [Received: 03/14/2021] [Accepted: 04/11/2021] [Indexed: 11/12/2022]
Affiliation(s)
- A Koh
- Department of Colorectal Surgery, Nottingham University Hospitals NHS Trust, Nottingham, UK.,Nottingham Breast Cancer Research Centre, University of Nottingham, Nottingham, UK
| | - R M Parks
- Nottingham Breast Cancer Research Centre, University of Nottingham, Nottingham, UK
| | - A Courtney
- Department of Surgery and Cancer, Imperial College London, London, UK
| | - D R Leff
- Department of Surgery and Cancer, Imperial College London, London, UK
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Koh A, Adiamah A, Sanyal S. 842 Safety and Efficacy of Tranexamic Acid to Minimise Perioperative Bleeding in Extrahepatic Abdominal Surgery: A Systematic Review. Br J Surg 2021. [DOI: 10.1093/bjs/znab134.584] [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] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Abstract
Introduction
Perioperative bleeding is a major risk during and after surgery, which can result in increased mortality and morbidity. Tranexamic acid (TXA), in the setting of trauma, minimises perioperative bleeding and its associated risks. However, there is a lack of evidence of its use in elective abdominal surgery. This meta-analysis of randomised controlled trials (RCTs) evaluated the effectiveness and safety of TXA in elective extrahepatic abdominal surgery.
Method
A comprehensive search of PubMed, Embase, and Clinicaltrial.gov databases was undertaken to identify RCTs from January 1947 to May 2020. The primary outcomes of intraoperative blood loss, and the secondary outcomes of need for perioperative blood transfusion, thromboembolic events, and mortality were extracted from included studies. Quantitative pooling of data was based on the random effects model.
Results
Nineteen studies reporting on 2205 patients were included. TXA reduced intraoperative blood loss (weighted mean difference (WMD) -188.35mL; 95% CI -254.65 to -121.72) and the need for perioperative blood transfusion (odds ratio (OR) 0.43; 95% CI 0.28 to 0.65). Importantly, TXA had no impact on the incidence of thromboembolic events (OR 0.49; 95% CI 0.18 to 1.35). There were no reported deaths in any of the studies.
Conclusions
TXA reduces intra-operative blood loss without an increase in complications.
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Affiliation(s)
- A Koh
- Nottingham University Hospitals NHS Trust, Nottingham, United Kingdom
| | - A Adiamah
- Nottingham University Hospitals NHS Trust, Nottingham, United Kingdom
| | - S Sanyal
- Nottingham University Hospitals NHS Trust, Nottingham, United Kingdom
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Koh A, Adiamah A, Gomez D, Sanyal S. Safety and efficacy of tranexamic acid in minimizing perioperative bleeding in extrahepatic abdominal surgery: meta-analysis. BJS Open 2021; 5:6220258. [PMID: 33839754 PMCID: PMC8038263 DOI: 10.1093/bjsopen/zrab004] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Accepted: 01/06/2021] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Perioperative bleeding is associated with increased morbidity and mortality in patients undergoing elective abdominal surgery. The antifibrinolytic agent tranexamic acid (TXA) has been shown to reduce perioperative bleeding and mortality risk in patients with traumatic injuries, but there is a lack of evidence for its use in elective abdominal and pelvic surgery. This meta-analysis of RCTs evaluated the effectiveness and safety of TXA in elective extrahepatic abdominopelvic surgery. METHODS PubMed, Embase, and ClinicalTrial.gov databases were searched to identify relevant RCTs from January 1947 to May 2020. The primary outcome, intraoperative blood loss, and secondary outcomes, need for perioperative blood transfusion, units of blood transfused, thromboembolic events, and mortality, were extracted from included studies. Quantitative pooling of data was based on a random-effects model. RESULTS Some 19 studies reporting on 2205 patients who underwent abdominal, pelvic, gynaecological or urological surgery were included. TXA reduced intraoperative blood loss (mean difference -188.35 (95 per cent c.i. -254.98 to -121.72) ml) and the need for perioperative blood transfusion (odds ratio (OR) 0.43, 95 per cent c.i. 0.28 to 0.65). TXA had no impact on the incidence of thromboembolic events (OR 0.49, 0.18 to 1.35). No adverse drug reactions or in-hospital deaths were reported. CONCLUSION TXA reduces intraoperative blood loss during elective extrahepatic abdominal and pelvic surgery without an increase in complications.
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Affiliation(s)
- A Koh
- Gastrointestinal Surgery, Nottingham Digestive Diseases Centre and National Institute for Health Research Biomedical Research Centre, Nottingham University Hospitals NHS Trust and University of Nottingham, Queen's Medical Centre, Nottingham, UK
| | - A Adiamah
- Gastrointestinal Surgery, Nottingham Digestive Diseases Centre and National Institute for Health Research Biomedical Research Centre, Nottingham University Hospitals NHS Trust and University of Nottingham, Queen's Medical Centre, Nottingham, UK
| | - D Gomez
- Gastrointestinal Surgery, Nottingham Digestive Diseases Centre and National Institute for Health Research Biomedical Research Centre, Nottingham University Hospitals NHS Trust and University of Nottingham, Queen's Medical Centre, Nottingham, UK
| | - S Sanyal
- Gastrointestinal Surgery, Nottingham Digestive Diseases Centre and National Institute for Health Research Biomedical Research Centre, Nottingham University Hospitals NHS Trust and University of Nottingham, Queen's Medical Centre, Nottingham, UK
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Ho J, Kovalik J, Gao F, Zhao X, Shuang L, Teo L, Tan R, Ewe S, Wee H, Ching J, Koh W, Zhong L, Koh A. Adverse cardiovascular ageing among older women and cardiometabolic ageing. Eur Heart J Cardiovasc Imaging 2021. [DOI: 10.1093/ehjci/jeaa356.421] [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: 11/12/2022] Open
Abstract
Abstract
Funding Acknowledgements
Type of funding sources: Public hospital(s). Main funding source(s): National Medical Research Council (NMRC)
Background
Despite longer life expectancies, women may experience reduced ‘health-span’ (period of life spent in good health) due to accumulation of risks over their longer life spans. Metabolic factors present in diet and lifestyle may provide modifiable solutions to tackle burdens of cardiovascular (CV) ageing in women.
Objective
We aim to study gender differences in CV structure and function among community older adults without clinical CV disease, as well as metabolic perturbations in their study samples.
Methods
We examined a prospective cohort study of older adults, obtaining their medical history, serum sampling, echocardiography and cardiac magnetic resonance (CMR) imaging on a single day visit. Echo E/A ratio was computed as a ratio of peak velocity flow in early diastole E (m/s) to peak velocity flow in late diastole by atrial contraction A (m/s) mitral inflow velocities. Longitudinal strain (ε) at any time point (t) in the cardiac cycle from end-diastole (time 0) was calculated as: ε(t)=(L(t)-L0)/L0, obtaining left atrial (LA) reservoir strain (εs), conduit strain (εe) and booster strain (εa) by CMR. Metabolomics profiling was performed by standard mass spectrometry techniques.
Results
Among n = 492 (49.6%, n = 244 women, mean age 73 ± 4 years) participants, women had lower prevalence of hypertension (52% vs 58%, p < 0.0001), smoking (4% vs 35%, p < 0.0001), but higher prevalence of dyslipidemia (52% vs 50%, p = 0.001) compared to men. Women had lower left ventricular mass index (69 vs 71 g/m2, p < 0.0001) compared to men. However, women had more adverse CV function, such as lower E/A ratio (0.78 vs 0.85, p < 0.0001), lower LA booster (εa) (16.5 vs 17.8, p = 0.027) and lower LA reservoir (εs) strain rate (1.5 vs 1.6, p = 0.012), compared to men. Amino acids such as alanine, arginine, aspartate, citrulline, glycine, phenylalanine and valine were similar between gender. However, women had higher levels of tyrosine (76 vs 68 μM, p = 0.015). On multivariate adjustment, apart from age, tyrosine was independently associated with E/A ratio (β=0.002, 95%CI 0.00-0.004, p = 0.044) and εs (β=0.004, 95%CI 0.00-0.009, p = 0.048) among women.
Conclusion
Utilizing conventional and sensitive CV imaging, women appeared to have more adverse CV functions with ageing. As a branched chain amino acid linked to future risk of CV disease, tyrosine may be linked to adverse CV function. Factors that contribute to these cardiometabolic profiles, such as menopause, diet or lifestyle warrant further research.
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Affiliation(s)
- J Ho
- National Heart Centre Singapore, Singapore, Singapore
| | - J Kovalik
- Singapore General Hospital, Singapore, Singapore
| | - F Gao
- National Heart Centre Singapore, Singapore, Singapore
| | - X Zhao
- National Heart Centre Singapore, Singapore, Singapore
| | - L Shuang
- National Heart Centre Singapore, Singapore, Singapore
| | - L Teo
- National Heart Centre Singapore, Singapore, Singapore
| | - R Tan
- National Heart Centre Singapore, Singapore, Singapore
| | - S Ewe
- National Heart Centre Singapore, Singapore, Singapore
| | - H Wee
- Duke-NUS Graduate Medical School Singapore, Singapore, Singapore
| | - J Ching
- Duke-NUS Graduate Medical School Singapore, Singapore, Singapore
| | - W Koh
- Duke-NUS Graduate Medical School Singapore, Singapore, Singapore
| | - L Zhong
- Duke-NUS Graduate Medical School Singapore, Singapore, Singapore
| | - A Koh
- National Heart Centre Singapore, Singapore, Singapore
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Koh A, Gao G, Chow V, Chew H, Ewe E, Teo L, Keng B, Tan R, Leng L, Zhao X, Zhong L, Tan H, Kovalik J, Koh W. Repurposing glycated hemoglobin as a possible marker of myocardial ageing in asymptomatic older adults. Eur Heart J 2020. [DOI: 10.1093/ehjci/ehaa946.3228] [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
The adverse consequences of diabetes mellitus on cardiovascular health is well-established. However, few studies have studied the impact of diabetes on ageing. In our previous investigations, we identified distinct patterns of myocardial ageing among older adults otherwise asymptomatic for clinical cardiovascular disease. In this analysis, we hypothesize that glycated hemoglobin (HbA1c) may be differentially associated with these distinct signatures of myocardial ageing, thereby providing greater precision towards future preventative trials.
Methods
We performed extensive cardiovascular examinations on a cohort of asymptomatic aged community adults. Transthoracic echocardiography measured left ventricular structure and function. LV filling pressure was measured as the ratio between early mitral inflow velocity and mitral annular early diastolic velocity. Longitudinal left atrial (LA) strain comprising reservoir strain (ɛs), conduit strain (ɛe) and booster strain (ɛa) and their corresponding peak strain rates (SRs, SRe, SRa) were measured using cardiac magnetic resonance (CMR) feature tracking technique. Blood sampling for biomarkers were performed simultaneously with cardiovascular examinations.
Results
Among n=515 community adults in sinus rhythm and without cardiovascular disease [mean age 73±4 years, 255 (50%) females], 116 (23%) had diabetes. Age (73 vs 73 years) and heart rate (72 vs 75 beats per minute) were similar between diabetic and non-diabetic older adults. Diabetic older adults are mostly male (59% vs 48%, p=0.046), had larger body mass indices (24 vs 23 kg/m2, p=0.027), and greater burdens of hypertension (81% vs 41%, p<0.0001) and dyslipidemia (79% vs 43%, p<0.0001), compared to non-diabetic older adults. Diabetics had worse LV myocardial relaxation [(ratio of peak velocity flow in early diastole E (m/s) to peak velocity flow in late diastole by atrial contraction A (m/s), 0.8±0.2 vs 0.9±0.3, p=0.031), worse LV filling pressures (10.9±3.1 vs 10.1±3.3, p=0.022), reductions in LA global strain (−33±17 vs −28±9.7, p=0.016), LA conduit strain ɛe (12±4.3 vs 14±4.1, p=0.045), increases in SRe (−1.2±0.4 vs −1.3±0.5, p=0.042) and reductions in SRe: SRa ratio (0.5±0.2 vs 0.7±0.3, p=0.0059) compared to non-diabetics. Based on multivariate analysis, HbA1c was independently associated with LV myocardial relaxation (β=−0.08 (−0.1, −0.03), p=0.002), LA conduit strain (β=−0.9, (−1.6, −0.1), p=0.025), LA conduit strain rate (β=0.1, (0.04, 0.2), p=0.005), strongly associated with LA global strain (β=3.0, (0.9, 5.1), p=0.006), but not associated with LV filling pressure (β=0.5 (−0.04, 1.0), p=NS).
Conclusion
Our detailed examinations revealed distinct associations between glycated hemoglobin and myocardial functions that additionally varied in magnitude. As a contemporary biomarker, glycated hemoglobin may be useful for stratifying risks associated with myocardial ageing, particularly in ageing-related left atrial myopathies.
Funding Acknowledgement
Type of funding source: Public Institution(s). Main funding source(s): National Medical Research Council of Singapore; Singhealth Foundation
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Affiliation(s)
- A Koh
- National Heart Centre Singapore; Duke-NUS Medical School, Singapore, Singapore
| | - G.F Gao
- National Heart Centre Singapore; Duke-NUS Medical School, Singapore, Singapore
| | - V.C Chow
- NATIONAL HEART CENTRE, Singapore, Singapore
| | - H.C Chew
- NATIONAL HEART CENTRE, Singapore, Singapore
| | - E.S.H Ewe
- National Heart Centre Singapore; Duke-NUS Medical School, Singapore, Singapore
| | - L.T Teo
- National Heart Centre Singapore; Duke-NUS Medical School, Singapore, Singapore
| | - B.M.H Keng
- NATIONAL HEART CENTRE, Singapore, Singapore
| | - R.S Tan
- National Heart Centre Singapore; Duke-NUS Medical School, Singapore, Singapore
| | - L.S Leng
- NATIONAL HEART CENTRE, Singapore, Singapore
| | - X.D Zhao
- NATIONAL HEART CENTRE, Singapore, Singapore
| | - L Zhong
- National Heart Centre Singapore; Duke-NUS Medical School, Singapore, Singapore
| | - H.C Tan
- Singapore General Hospital, Singapore, Singapore
| | - J.P Kovalik
- Duke-NUS Graduate Medical School Singapore, Singapore, Singapore
| | - W.P Koh
- Duke-NUS Graduate Medical School Singapore, Saw Swee Hock School of Public Health, NUS, Singapore, Singapore
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De S, White J, Brusuelas T, Patton C, Koh A, Huang Q. Electrochemical behavior of protons and cupric ions in water in salt electrolytes with alkaline metal chloride. Electrochim Acta 2020. [DOI: 10.1016/j.electacta.2020.135852] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Koh A, Chowdhury A, Adiamah A. Therapeutic role of water-soluble contrast media in adhesive small bowel obstruction: A systematic review. Int J Surg 2018. [DOI: 10.1016/j.ijsu.2018.05.194] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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9
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Koh A, Thomas P, Adiamah A. Early definitive treatment for gallstone pancreatitis: Compliance with guidelines and readmission data. Int J Surg 2018. [DOI: 10.1016/j.ijsu.2018.05.296] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Koh A, Guerado E, Giannoudis PV. Atypical femoral fractures related to bisphosphonate treatment: issues and controversies related to their surgical management. Bone Joint J 2017; 99-B:295-302. [PMID: 28249967 DOI: 10.1302/0301-620x.99b3.bjj-2016-0276.r2] [Citation(s) in RCA: 81] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Accepted: 11/21/2016] [Indexed: 12/12/2022]
Abstract
AIMS Treatment guidelines for atypical femoral fractures associated with bisphosphonates have not been established. We conducted a systematic review of the treatment of atypical femoral fractures first, to evaluate the outcomes of surgical fixation of complete atypical fractures and secondly, to assess whether prophylactic surgery is necessary for incomplete atypical fractures. MATERIALS AND METHODS Case reports and series were identified from the PubMed database and were included if they described the treatment of atypical femoral fractures. In total, 77 publications met our inclusion criteria and 733 patients with 834 atypical complete or incomplete femoral fractures were identified. RESULTS For complete fractures, internal fixation was predominantly achieved by intramedullary nailing. The mean time to healing post-operatively was 7.3 months (2 to 31). Revision surgery for nonunion or implant failure was needed in 77 fractures (12.6%). A greater percentage of fractures treated with plate fixation (31.3%) required revision surgery than those treated with intramedullary nailing (12.9%) (p < 0.01). Non-operative treatment of incomplete fractures failed and surgery was eventually needed in nearly half of the patients (47%), whereas prophylactic surgery was successful and achieved a 97% rate of healing. CONCLUSION Intramedullary nailing is the first-line treatment for a complete fracture, although the risk of delayed healing and revision surgery seems to be higher than with a typical femoral fracture. Non-operative treatment does not appear to be a reliable way of treating an incomplete fracture: prophylactic intramedullary nailing should be considered if the patient is in intractable pain. Radiographs of the opposite side should be obtained routinely looking for an asymptomatic fracture. Bisphosphonates must be discontinued but ongoing metabolic management in the form of calcium and/or vitamin D supplements is advisable. Teriparatide therapy can be considered as an alternative treatment. Cite this article: Bone Joint J 2017;99-B:295-302.
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Affiliation(s)
- A Koh
- Kobe Rosai Hospital, 4-1-23 Kagoike-dori, Chuo-ku, Kobe, 651-0053, Japan
| | - E Guerado
- University of Malaga, Autovia A-7 K, 187 29603, Marbella, Malaga, Spain
| | - P V Giannoudis
- NIHR Leeds Biomedical Research Unit, Chapel Allerton Hospital, LS7 4SA Leeds, West Yorkshire, Leeds, UK
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Senior PA, Koh A, Yau J, Imes S, Dinyari P, Malcolm AJ, Light P, Shapiro AMJ. Sitagliptin plus pantoprazole can restore but not maintain insulin independence after clinical islet transplantation: results of a pilot study. Diabet Med 2017; 34:204-212. [PMID: 27087519 DOI: 10.1111/dme.13131] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [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] [Accepted: 04/11/2016] [Indexed: 01/13/2023]
Abstract
AIMS Resuming insulin use due to waning function is common after islet transplantation. Animal studies suggest that gastrointestinal hormones, including gastrin and incretins may increase β-cell mass. We tested the hypothesis that pantoprazole plus sitagliptin, would restore insulin independence in islet transplant recipients with early graft insufficiency and determined whether this would persist after a 3-month washout. METHODS Single-centre, uncontrolled, open label study of sitagliptin 100 mg daily plus pantoprazole 40 mg twice daily for 6 months. RESULTS After 6 months of treatment, two of eight participants (25%) achieved the primary endpoint, defined as HbA1C < 42 mmol/mol (6%), fasting plasma glucose < 7.0 mmol, C-peptide > 0.5 nmol and no insulin use. There was a significant reduction in mean insulin dose, but no change in HbA1C or weight. There were no changes in the acute insulin response to arginine, the mixed meal tolerance test or blinded continuous glucose monitoring. After the washout, no participants met the primary endpoint and HbA1C increased from 45 ± 8 mmol/mol (6.3 ± 0.7%) to 51 ± 6 mmol/mol (6.8 ± 0.6%) (P < 0.05). Two participants had mild-moderate transient gastrointestinal side effects. There were no episodes of hypoglycaemia. CONCLUSIONS Sitagliptin plus pantoprazole is well tolerated and safe and may restore insulin independence in some islet transplant recipients with early graft insufficiency, but this was not sustained when treatment was withdrawn. A larger, controlled trial is required to confirm the effectiveness of this combination to achieve insulin independence and to confidently exclude any persistent benefit for graft function. (Clinical Trials Registry No.: NCT00768651).
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Affiliation(s)
- P A Senior
- Clinical Islet Transplant Program, Edmonton, Canada
- Alberta Diabetes Institute, University of Alberta, Edmonton, Canada
| | - A Koh
- Clinical Islet Transplant Program, Edmonton, Canada
| | - J Yau
- Clinical Islet Transplant Program, Edmonton, Canada
| | - S Imes
- Clinical Islet Transplant Program, Edmonton, Canada
| | - P Dinyari
- Clinical Islet Transplant Program, Edmonton, Canada
| | - A J Malcolm
- Clinical Islet Transplant Program, Edmonton, Canada
| | - P Light
- Alberta Diabetes Institute, University of Alberta, Edmonton, Canada
| | - A M J Shapiro
- Clinical Islet Transplant Program, Edmonton, Canada
- Alberta Diabetes Institute, University of Alberta, Edmonton, Canada
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Lee W, Choi J, Bae J, Koh A, Jung U, Ko J. Laparoscopic Restaging Surgery in Patients With Unexpected Uterine Cancer. J Minim Invasive Gynecol 2016; 22:S152. [PMID: 27678861 DOI: 10.1016/j.jmig.2015.08.560] [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: 10/22/2022]
Affiliation(s)
- W Lee
- Division of Gynecologic Oncology and Gynecologic Minimally Invasive Surgery, Department of Obstetrics and Gynecology, Hanyang University College of Medicine, Seoul, Republic of Korea
| | - J Choi
- Division of Gynecologic Oncology and Gynecologic Minimally Invasive Surgery, Department of Obstetrics and Gynecology, Hanyang University College of Medicine, Seoul, Republic of Korea
| | - J Bae
- Division of Gynecologic Oncology and Gynecologic Minimally Invasive Surgery, Department of Obstetrics and Gynecology, Hanyang University College of Medicine, Seoul, Republic of Korea
| | - A Koh
- Division of Gynecologic Oncology and Gynecologic Minimally Invasive Surgery, Department of Obstetrics and Gynecology, Hanyang University College of Medicine, Seoul, Republic of Korea
| | - U Jung
- Department of Obstetrics and Gynecology, Hallym University Hangang Sacred Heart Hospital, Seoul, Republic of Korea
| | - J Ko
- Department of Obstetrics and Gynecology, Kangwon National University Hospital, Chuncheon, Kangwon-do, Republic of Korea
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Takizawa T, Shibata M, Kayama Y, Shimizu T, Toriumi H, Ebine T, Koh A, Suzuki N. EHMTI-0324. Expression of high-mobility group box 1 in the cerebral cortex after cortical spreading depression. J Headache Pain 2014. [PMCID: PMC4181997 DOI: 10.1186/1129-2377-15-s1-f26] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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14
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DeMasi J, Cox J, Koh A, Aquino V. Safety and Efficacy of Intravenous Pentamidine in Children and Adolescents Undergoing Hematopoietic Stem Cell Transplantation. Biol Blood Marrow Transplant 2012. [DOI: 10.1016/j.bbmt.2011.12.300] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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Bailey J, Pavlock T, Germann J, Koh A, Aquino V. Evaluating Fatigue and Hope in Pediatric Hematopoietic Stem Cell Transplantation Recipients. Biol Blood Marrow Transplant 2012. [DOI: 10.1016/j.bbmt.2011.12.488] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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16
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Gala-Lopez BL, Senior PA, Koh A, Kashkoush SM, Kawahara T, Kin T, Humar A, Shapiro AMJ. Late cytomegalovirus transmission and impact of T-depletion in clinical islet transplantation. Am J Transplant 2011; 11:2708-14. [PMID: 21906252 DOI: 10.1111/j.1600-6143.2011.03724.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [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: 02/05/2023]
Abstract
The epidemiology of cytomegalovirus infection (CMV) in islet transplantation (IT) is not well defined. This study defines incidence, transmission and clinical sequelae of CMV reactivation or disease in 121 patients receiving 266 islet infusions at a single institution. The donor (D)/recipient (R) serostatus was D+/R- 31.2%, D+/R+ 26.3%, D-/R+ 13.2% and D-/R- 29.3%. CMV prophylaxis with oral ganciclovir/valganciclovir was given in 68%. CMV infection occurred in 14/121 patients (11.6%); six had asymptomatic seroconversion and eight others had positive viremia (six asymptomatic and two with CMV febrile symptoms). Median peak viral loads were 1755 copies/mL (range 625-9 100 000). Risk factors for viremia included lymphocyte depletion (thymoglobulin or alemtuzumab, p < 0.001). Viremia was more common in D+/R+ versus D+/R- (p = 0.12), occurring mostly late after transplant (median 306 days). Presumed transmission from IT occurred in 8/83 of D+/R- procedures (9.6%). Of the two cases of CMV disease, one resulted from islet transmission from a CMV positive donor (D+/R-); the other was due to de novo exogenous infection (D-/R-). Therefore, CMV transmission presents rarely after IT and with low incidence compared to solid organ transplantation, but occurs late posttransplant. The use of lymphocyte depleting therapies is a primary risk factor.
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Affiliation(s)
- B L Gala-Lopez
- Clinical Islet Transplant Program, University of Alberta, Edmonton, Alberta, Canada
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Senior PA, Koh A, Shapiro AMJ. Remission of alopecia universalis following successful clinical islet transplantation. Am J Transplant 2011; 11:2536-7. [PMID: 21951462 DOI: 10.1111/j.1600-6143.2011.03758.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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Wong J, Chan YH, Ho CY, Koh A, Goh CY, Lee HH, Kwa W, Yeo D. Quality of life in Southeast Asian patients with chronic heart failure in Singapore. Heart 2011. [DOI: 10.1136/heartjnl-2011-300867.264] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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Koh A, Lim TH, Au Eong KG, Chee C, Ong SG, Tan N, Yeo I, Wong D. Optimising the management of choroidal neovascularisation in Asian patients: consensus on treatment recommendations for anti-VEGF therapy. Singapore Med J 2011; 52:232-240. [PMID: 21552782] [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: 05/30/2023]
Abstract
In Asian countries, age-related macular degeneration (AMD), specifically wet AMD or choroidal neovascularisation (CNV), is an important cause of blindness and visual handicap. Vascular endothelial growth factors (VEGF) play an integral role in the development of CNV and thus provide an important therapeutic target. Current treatment paradigms for neovascular AMD recognise the place of photodynamic therapy (PDT) in the management of this condition. However, combination therapy targeting different pathways to produce a synergistic effect may result in improved visual outcomes and reduced duration of treatment. Anti-VEGF therapy has greatly improved treatment outcomes in patients with CNV, and a growing body of evidence supports the role of these agents as monotherapy or in combination with PDT. In particular, anti-VEGF may be a first-line treatment option in certain types of subfoveal myopic CNV as well as for classic and occult juxtafoveal and subfoveal CNV. The implementation of evidence-based medicine into current clinical practice is paramount to improving patient care. The authors, who are also members of the Singapore Medical Retina Advisory Board, outline the consensus points and recommended treatment algorithms based on currently available knowledge to provide a structured management approach to the treatment of Asian patients with CNV.
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Affiliation(s)
- A Koh
- Eye and Retina Surgeons, Camden Medical Centre, 1 Orchard Boulevard, Singapore 248649.
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Jermendy A, Toschi E, Aye T, Koh A, Aguayo-Mazzucato C, Sharma A, Weir GC, Sgroi D, Bonner-Weir S. Rat neonatal beta cells lack the specialised metabolic phenotype of mature beta cells. Diabetologia 2011; 54:594-604. [PMID: 21240476 PMCID: PMC3045081 DOI: 10.1007/s00125-010-2036-x] [Citation(s) in RCA: 83] [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: 08/31/2010] [Accepted: 11/25/2010] [Indexed: 01/01/2023]
Abstract
AIMS/HYPOTHESIS Fetal and neonatal beta cells have poor glucose-induced insulin secretion and only gain robust glucose responsiveness several weeks after birth. We hypothesise that this unresponsiveness is due to a generalised immaturity of the metabolic pathways normally found in beta cells rather than to a specific defect. METHODS Using laser-capture microdissection we excised beta cell-enriched cores of pancreatic islets from day 1 (P1) neonatal and young adult Sprague-Dawley rats in order to compare their gene-expression profiles using Affymetrix U34A microarrays (neonatal, n = 4; adult, n = 3). RESULTS Using dChip software for analysis, 217 probe sets for genes/38 expressed sequence tags (ESTs) were significantly higher and 345 probe sets for genes/33 ESTs significantly lower in beta cell-enriched cores of neonatal islets compared with those of adult islets. Among the genes lower in the neonatal beta cells were key metabolic genes including mitochondrial shuttles (malate dehydrogenase, glycerol-3-phosphate dehydrogenase and glutamate oxalacetate transaminase), pyruvate carboxylase and carnitine palmitoyl transferase 2. Differential expression of these enzyme genes was confirmed by quantitative PCR on RNA from isolated neonatal (P2 until P28) and adult islets and with immunostaining of pancreas. Even by 28 days of age some of these genes were still expressed at lower levels than in adults. CONCLUSIONS/INTERPRETATION The lack of glucose responsiveness in neonatal islets is likely to be due to a generalised immaturity of the metabolic specialisation of pancreatic beta cells.
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Affiliation(s)
- A. Jermendy
- Section on Islet Cell and Regenerative Biology, Research Division, Joslin Diabetes Center, Department of Medicine, Harvard Medical School, One Joslin Place, Boston, MA 02215, USA; 1st Department of Pediatrics, Semmelweis University, Budapest, Hungary
| | - E. Toschi
- Section on Islet Cell and Regenerative Biology, Research Division, Joslin Diabetes Center, Department of Medicine, Harvard Medical School, One Joslin Place, Boston, MA 02215, USA
| | - T. Aye
- Section on Islet Cell and Regenerative Biology, Research Division, Joslin Diabetes Center, Department of Medicine, Harvard Medical School, One Joslin Place, Boston, MA 02215, USA
| | - A. Koh
- Section on Islet Cell and Regenerative Biology, Research Division, Joslin Diabetes Center, Department of Medicine, Harvard Medical School, One Joslin Place, Boston, MA 02215, USA
| | - C. Aguayo-Mazzucato
- Section on Islet Cell and Regenerative Biology, Research Division, Joslin Diabetes Center, Department of Medicine, Harvard Medical School, One Joslin Place, Boston, MA 02215, USA
| | - A. Sharma
- Section on Islet Cell and Regenerative Biology, Research Division, Joslin Diabetes Center, Department of Medicine, Harvard Medical School, One Joslin Place, Boston, MA 02215, USA
| | - G. C. Weir
- Section on Islet Cell and Regenerative Biology, Research Division, Joslin Diabetes Center, Department of Medicine, Harvard Medical School, One Joslin Place, Boston, MA 02215, USA
| | - D. Sgroi
- Molecular Pathology Unit, Massachusetts General Hospital, Department of Pathology, Harvard Medical School, Boston, MA, USA
| | - S. Bonner-Weir
- Section on Islet Cell and Regenerative Biology, Research Division, Joslin Diabetes Center, Department of Medicine, Harvard Medical School, One Joslin Place, Boston, MA 02215, USA
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Aguayo-Mazzucato C, Koh A, El Khattabi I, Li WC, Toschi E, Jermendy A, Juhl K, Mao K, Weir GC, Sharma A, Bonner-Weir S. Mafa expression enhances glucose-responsive insulin secretion in neonatal rat beta cells. Diabetologia 2011; 54:583-93. [PMID: 21190012 PMCID: PMC3047400 DOI: 10.1007/s00125-010-2026-z] [Citation(s) in RCA: 122] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/16/2010] [Accepted: 11/25/2010] [Indexed: 12/21/2022]
Abstract
AIM/HYPOTHESIS Neonatal beta cells lack glucose-stimulated insulin secretion and are thus functionally immature. We hypothesised that this lack of glucose responsiveness results from a generalised low expression of genes characteristic of mature functional beta cells. Important glucose-responsive transcription factors, Mafa and Pdx1, regulate genes involved in insulin synthesis and secretion, and have been implicated in late beta cell development. The aim of this study was to assess whether Mafa and/or Pdx1 regulates the postnatal functional maturation of beta cells. METHODS By quantitative PCR we evaluated expression of these and other beta cell genes over the first month compared with adult. After infection with adenovirus expressing MAFA, Pdx1 or green fluorescent protein (Gfp), P2 rat islets were evaluated by RT-PCR and insulin secretion with static incubation and reverse haemolytic plaque assay (RHPA). RESULTS At P2 most beta cell genes were expressed at about 10% of adult, but by P7 Pdx1 and Neurod1 no longer differ from adult; by contrast, Mafa expression remained significantly lower than adult through P21. Overexpression of Pdx1 increased Mafa, Neurod1, glucokinase (Gck) mRNA and insulin content but failed to enhance glucose responsiveness. Similar overexpression of MAFA resulted in increased Neurod1, Nkx6-1, Gck and Glp1r mRNAs and no change in insulin content but, importantly, acquisition of glucose-responsive insulin secretion. Both the percentage of secreting beta cells and the amount of insulin secreted per beta cell increased, approaching that of adult beta cells. CONCLUSIONS/INTERPRETATION In the process of functional maturation acquiring glucose-responsive insulin secretion, neonatal beta cells undergo a coordinated gene expression programme in which Mafa plays a crucial role.
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Goh KP, Chew K, Koh A, Guan M, Wong YS, Sum CF. The relationship between ACE gene ID polymorphism and aerobic capacity in Asian rugby players. Singapore Med J 2009; 50:997-1003. [PMID: 19907891] [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: 05/28/2023]
Abstract
INTRODUCTION The aim of this study was to analyse the association between the ACE ID polymorphism and aerobic capacity in a homogeneous cohort of national Asian rugby players. METHODS 17 subjects recruited during active training had their maximal oxygen uptake (V0 2 max) and ventilatory threshold (VT) measured during maximal exercise testing. ACE genotyping was performed for all players. RESULTS The likelihood of having a V0 2 max above the 80th percentile of a gender-specific reference range for a normal population was 14.3-fold greater among subjects with the II genotype as compared to the ID genotype (p-value is 0.030). Similarly, subjects with the II genotype were 29.4 times more likely to have a VT above the gender-specific median value compared to the ID genotype (p-value is 0.019). The results suggest that the I allele confers an advantage in aerobic capacity as measured by the V0 2 max and VT. CONCLUSION It is likely that the same physiological mechanisms mediated by the ACE gene are responsible for aerobic capacity in both Asians and Caucasians.
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Affiliation(s)
- K P Goh
- Department of Medicine, Alexandra Hospital, 378 Alexandra Road, Singapore.
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Suzuki T, Amano K, Kagawa K, Tsujikawa A, Ogata K, Uchida T, Koh A, Otaki M, Kato H, Seita I, Tamura A, Fujita S, Takahashi Y, Tanaka A, Koshihara K, Nishida Y, Yamamoto Y, Fukutake K. CONTINUOUS INFUSION OF VON WILLEBRAND FACTOR/FACTOR VIII CONCENTRATE IN PATIENTS WITH CONGENITAL VON WILLEBRAND DISEASE. J Thromb Haemost 2007. [DOI: 10.1111/j.1538-7836.2007.tb02732.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Lim SC, Goh SK, Lai YR, Tee WW, Koh A, Xu XH, Wu YS, Yap E, Subramaniam T, Sum CF. Relationship between common functional polymorphisms of the p22phox gene (-930A > G and +242C > T) and nephropathy as a result of Type 2 diabetes in a Chinese population. Diabet Med 2006; 23:1037-41. [PMID: 16922713 DOI: 10.1111/j.1464-5491.2006.01916.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [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: 11/30/2022]
Abstract
OBJECTIVE Genetic determinants are important in diabetic nephropathy (DN). Oxidative stress has also emerged as an important pathogenic factor in DN and vascular NADH oxidase is a major source of reactive oxygen species (ROS). Previous small studies reported a strong but contradictory association between functional genetic variation of p22(phox), an important subcomponent of NADH oxidase, and DN. We investigated the association between two common functional single nucleotide polymorphisms (SNPs) (-930 A > G and +242 C > T) and DN in a much larger group of Chinese patients with Type 2 diabetes mellitus (T2DM). RESEARCH DESIGN AND METHODS Case-control study of Chinese subjects with long-standing T2DM (> 10 years). Cases (n = 306) were subjects with a spot urinary albumin : creatinine ratio (ACR) of > 113 mg/mmol or elevated serum creatinine. Control subjects (n = 306) had ACR < 3.3 mg/mmol and normal serum creatinine. Genotyping was carried out by standard PCR and restriction fragment length polymorphism analysis. RESULTS Gender distribution, age, duration of diabetes and HbA(1c) were similar in cases and control subjects. Distribution of genotypes in the control subjects for both SNPs was consistent with the Hardy-Weinberg equilibrium. Distribution of genotypes did not differ significantly between cases and control subjects for both polymorphisms-+2424C > T: cases CC 84.6%, CT 15.0%, TT 0.4% and control subjects CC 87.6%, CT 11.8%, TT 0.6% (P = 0.45); -930 A > G: cases AA 40.5%, AG 41.8%, GG 17.7% and control subjects AA 38.2%, AG 49.0%, GG 12.8% (P = 0.12). Distribution of alleles was also similar-+2424 C > T: cases C 92.2%, T 7.8% and control subjects C 93.5%, T 6.5% (P = 0.66); -930 A > G cases A 61.4%, G 38.6% and control subjects A 62.7%, G 37.3% (P = 0.38). We estimated that our study has approximately 80% power to detect a relative risk of 1.65 (for +242 C > T) and 1.35 (for -930 A > G) conferred by the minor allele, respectively. CONCLUSIONS In contrast with previous small studies, our data suggest that these SNPs do not confer significantly increased susceptibility to DN secondary to T2DM in Chinese subjects.
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Affiliation(s)
- S C Lim
- Department of Medicine, Alexandra Hospital, Singapore.
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Teoh SCB, Lim J, Koh A, Lim T, Fu E. Abnormalities on the multifocal electroretinogram may precede clinical signs of hydroxychloroquine retino-toxicity. Eye (Lond) 2006; 20:129-32. [PMID: 15731769 DOI: 10.1038/sj.eye.6701818] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
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Butterfield LH, Meng WS, Koh A, Vollmer CM, Ribas A, Dissette VB, Faull K, Glaspy JA, McBride WH, Economou JS. T cell responses to HLA-A*0201-restricted peptides derived from human alpha fetoprotein. J Immunol 2001; 166:5300-8. [PMID: 11290817 DOI: 10.4049/jimmunol.166.8.5300] [Citation(s) in RCA: 106] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
alpha fetoprotein (AFP)-derived peptide epitopes can be recognized by human T cells in the context of MHC class I. We determined the identity of AFP-derived peptides, presented in the context of HLA-A*0201, that could be recognized by the human (h) T cell repertoire. We screened 74 peptides and identified 3 new AFP epitopes, hAFP(137-145), hAFP(158-166), and hAFP(325-334), in addition to the previously reported hAFP(542-550.) Each possesses two anchor residues and stabilized HLA-A*0201 on T2 cells in a concentration-dependent class I binding assay. The peptides were stable for 2-4 h in an off-kinetics assay. Each peptide induced peptide-specific T cells in vitro from several normal HLA-A*0201 donors. Importantly, these hAFP peptide-specific T cells also were capable of recognizing HLA-A*0201(+)/AFP(+) tumor cells in both cytotoxicity assays and IFN-gamma enzyme-linked immunospot assays. The immunogenicity of each peptide was tested in vivo with HLA-A*0201/K(b)-transgenic mice. After immunization with each peptide emulsified in CFA, draining lymph node cells produced IFN-gamma on recognition of cells stably transfected with hAFP. Furthermore, AFP peptide-specific T cells could be identified in the spleens of mice immunized with dendritic cells transduced with an AFP-expressing adenovirus (AdVhAFP). Three of four AFP peptides could be identified by mass spectrometric analysis of surface peptides from an HLA-A*0201 human hepatocellular carcinoma (HCC) cell line. Thus, compelling immunological and physiochemical evidence is presented that at least four hAFP-derived epitopes are naturally processed and presented in the context of class I, are immunogenic, and represent potential targets for hepatocellular carcinoma immunotherapy.
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Affiliation(s)
- L H Butterfield
- Division of Surgical Oncology, Department of Chemistry and Biochemistry, University of California Los Angeles Medical Center, Los Angeles, CA 90095, USA
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Abstract
A cucurbit protoplast isolation protocol was established for the study of plant virus replication in vivo. This protocol is applicable to both cucumber and squash leaf tissue with significant increases in yields of viable protoplasts suitable for electroporation, compared to other published methods. A combination of Cellulase RS, Macerozyme R10 and mannitol was used as digestion enzymes and osmoticum. An average of 1.7x10(7) protoplasts per gram of fresh leaf tissue were obtained from cucumber cultivar Bet-alpha. Both cucumber cultivar Shimson and squash cultivar First Taste produced an average yield of 6.0x10(6) protoplasts per g of fresh leaf tissue. Electroporation of 10 microg of Zucchini yellow mosaic potyvirus (ZYMV-S) RNA into the protoplasts resulted in virus replication and synthesis of coat protein (CP). SDS-PAGE and immunoblotting were used to detect the CP 48 h post-electroporation. This protocol is highly reproducible and will assist researchers who require cucurbit protoplasts to study virus replication.
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Affiliation(s)
- K C Lee
- Department of Biological Sciences, National University of Singapore, Lower Kent Ridge Road, 117543, Singapore, Singapore
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Abstract
The stability of poly(dimethylsiloxane) (PDMS) oil-in-water emulsions has been investigated in the presence of added NaCl as well as in the presence of added surfactant. The emulsions were prepared using a combination of nonionic (C(x)E(y), x and y represent the number of methylene (C) and ethylene oxide (E) groups, respectively) and cationic (quarternary alkylammonium) surfactants. The droplets were observed to exhibit weak flocculation in the presence of high NaCl concentration (1 M). Phase separation and optical microscopic observations revealed that the principal mechanism for emulsion destabilization at high salt concentration was coalescence, which was accelerated at elevated temperature (50 degrees C). The effective coalescence rate for diluted emulsions was investigated using photon correlation spectroscopy. The small effective Hamaker constant for PDMS is the primary reason for the slow rate of coalescence observed for the emulsions at neutral pH in the presence of NaCl. The stability of PDMS emulsions to flocculation is qualitatively similar to that reported for low Hamaker constant dispersions (e.g., microgel particles). Addition of cationic surfactants (cetyltrimethylammonium chloride and dodecyl dimethylbenzylammonium chloride) to the negatively charged droplets after preparation was shown to decrease the emulsion stability once the surfactant concentration exceeded the CMC. Electrophoretic mobility measurements showed that added cationic surfactant changed the sign of the droplet charge from negative to positive at concentrations well below the CMC. Charged micelles of the same sign as the droplets are electrostatically excluded from close approach to the droplet surface within a distance (varepsilon) which results in depletion flocculation. Copyright 2000 Academic Press.
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Affiliation(s)
- A Koh
- Colloid and Polymer Chemistry Research Group, Department of Chemistry, University of Adelaide, North Terrace, Adelaide, South Australia, 5005, Australia
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Affiliation(s)
- A Koh
- St Bartholomew's Hospital, London
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Ribas A, Butterfield LH, Hu B, Dissette VB, Meng WS, Koh A, Andrews KJ, Lee M, Amar SN, Glaspy JA, McBride WH, Economou JS. Immune deviation and Fas-mediated deletion limit antitumor activity after multiple dendritic cell vaccinations in mice. Cancer Res 2000; 60:2218-24. [PMID: 10786687] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
Genetic immunization with a single injection of dendritic cells (DCs) expressing a model melanoma antigen generates antigen-specific, MHC-restricted, protective immune responses. After initiating the immune response, additional vaccinations may increase the protection or conversely downregulate the immune response. Groups of mice were vaccinated several times with DCs transduced with the MART-1 gene, and the anti-tumor protection was compared with that of mice receiving a single vaccination. C3H mice had poorer protection from a syngeneic MART-1-expressing tumor challenge with multiple vaccinations. This was accompanied by lower levels of splenic CTL effectors and a shift from a type 1 to a type 2 cytokine profile. On the contrary, multiple vaccinations in C57BL/6 mice generated greater in vivo antitumor protection with no decrease in splenic CTLs and no cytokine shift. Antiadenoviral humoral or cellular immune responses did not seem to contribute to these effects. When studies were performed in Fas receptor-negative C3H.(lpr) mice, the adverse effect of multiple vaccinations disappeared, and there was no cytokine shift pattern. In conclusion, C3H mice but not C57BL/6 mice receiving multiple vaccinations with DCs expressing the MART-1 tumor antigen show decreased protection associated with deviation from a type 1 to a type 2 cytokine response attributable to a Fas-receptor mediated clearance of antigen-specific IFN-gamma-producing cells.
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Affiliation(s)
- A Ribas
- Division of Surgical Oncology, University of California at Los Angeles, 90095, USA
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Affiliation(s)
- A Koh
- St Bartholomew's Hospital, London
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Affiliation(s)
- A Koh
- St Bartholomew's Hospital, London
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Abstract
PURPOSE This study examined whether safe and effective mydriasis can be achieved in premature infants with heavily pigmented irides using combination cyclopentolate 0.2% and phenylephrine 1% eyedrops. METHODS A prospective, randomized double-blind study was performed to compare combination cyclopentolate 0.2% and phenylephrine 1% eye-drops with triple instillation of tropicamide 0.5% and phenylephrine 2.5%. Twenty-eight consecutive babies with dark irides and birthweight <1600 g referred for screening for retinopathy of prematurity comprised the study population. Infants' eyes were randomly dilated twice with both regimens within a 2-week period. Blood pressure, heart rate, and pupil size were measured. RESULTS Good mydriasis was achieved in both groups with no significant differences in pupil size or blood pressure (systolic, diastolic, or mean arterial pressures) over starting baseline values. Pulse rates decelerated below the baseline values in both groups, but these differences were not large. CONCLUSION The single combination eyedrop of cyclopentolate 0.2% and phenylephrine 1% is as effective and safe a mydriatic for infants with dark irides as both tropicamide 0.5% and phenylephrine 2.5%.
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Affiliation(s)
- B K Khoo
- Department of Neonatology I, Kandang Kerbau Hospital, Singapore
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Ribas A, Butterfield LH, Hu B, Dissette VB, Chen AY, Koh A, Amarnani SN, Glaspy JA, McBride WH, Economou JS. Generation of T-cell immunity to a murine melanoma using MART-1-engineered dendritic cells. J Immunother 2000; 23:59-66. [PMID: 10687138 DOI: 10.1097/00002371-200001000-00008] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.0] [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] [Indexed: 11/25/2022]
Abstract
The murine melanoma B16 expresses the murine counterpart of the human MART-1/Melan-A (MART-1) antigen, sharing a 68.6% amino acid sequence identity. In this study, mice were vaccinated with bone marrow-derived murine dendritic cells genetically modified with a replication-incompetent adenoviral vector to express the human MART-1 gene (AdVMART1). This treatment generated a protective response to a lethal tumor challenge of unmodified murine B16 melanoma cells. The response was mediated by major histocompatibility complex class I-restricted cytotoxic T lymphocytes specific for MART-1 antigen, which produced high levels of interferon-gamma when reexposed to MART-1 in vitro and lysed targets in a calcium-dependent mechanism suggestive of perforin/granzyme B lysis. MART-1 was presented by the dendritic cells used for vaccination and not by epitopes cross-presented by host antigen-presenting cells. In conclusion, dendritic cells genetically modified to express the human MART-1 antigen generate potent murine MART-1-specific protective responses to B16 melanoma.
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Affiliation(s)
- A Ribas
- Division of Surgical Oncology, University of California, Los Angeles, USA
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Ribas A, Butterfield LH, McBride WH, Dissette VB, Koh A, Vollmer CM, Hu B, Chen AY, Glaspy JA, Economou JS. Characterization of antitumor immunization to a defined melanoma antigen using genetically engineered murine dendritic cells. Cancer Gene Ther 1999; 6:523-36. [PMID: 10608349 DOI: 10.1038/sj.cgt.7700076] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
A murine model of dendritic cell (DC)-based genetic immunization to a defined human melanoma antigen (Ag), MART-1/Melan-A (MART-1), was developed. The MART-1 gene was stably transfected into the nonimmunogenic mouse fibrosarcoma cell line NFSA that is syngeneic in C3Hf/Sem/Kam (C3H, H-2k) mice to generate the NFSA(MART1) cell line. In vivo protection from a lethal NFSA(MART1) tumor challenge could be generated by DCs transduced with a recombinant adenovirus (AdV) vector expressing MART-1 (AdVMART1). This model has the following characteristics: (a) immunological specificity and memory, (b) comparable protection for varying transduction multiplicities of infection, cell doses, and sites of DC inoculation but, interestingly, worse protection with increasing numbers of vaccinations, (c) the ability to treat small established tumors, (d) an absolute requirement for CD8 and CD4 T cells, (e) generation of MART-1-specific splenic cytotoxic T lymphocytes, and (f) up-regulation of both T helper type 1 and T helper type 2 cytokines. Genetically engineered DCs presenting defined tumor Ags represent an attractive method to generate effective immune responses.
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Affiliation(s)
- A Ribas
- Division of Surgical Oncology, University of California, Los Angeles 90095, USA
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Affiliation(s)
- A Koh
- St Bartholomew's School of Nursing and Midwifery, London
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Koh A, Jones S, Chaffer D, Kirby C. Funding the future. Nurs Stand 1999; 13:52-5. [PMID: 10661210 DOI: 10.7748/ns.13.50.52.s51] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/14/2023]
Affiliation(s)
- A Koh
- St Bartholomew's Hospital, London
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Butterfield LH, Koh A, Meng W, Vollmer CM, Ribas A, Dissette V, Lee E, Glaspy JA, McBride WH, Economou JS. Generation of human T-cell responses to an HLA-A2.1-restricted peptide epitope derived from alpha-fetoprotein. Cancer Res 1999. [PMID: 10397256 DOI: 10.1016/j.jval.2015.09.564] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Alpha-fetoprotein (AFP) is often derepressed in human hepatocellular carcinoma. Peptide fragments of AFP presented in the context of major histocompatibility molecules could serve as potential recognition targets by CD8 T cells, provided these lymphocytes were not clonally deleted in ontogeny. We therefore wished to determine whether the human T-cell repertoire could recognize AFP-derived peptide epitopes in the context of a common class I allele, HLA-A2.1. Dendritic cells genetically engineered to express AFP were capable of generating AFP-specific T-cell responses in autologous human lymphocyte cultures and in HLA-A2.1/Kb transgenic mice. These T cells recognize a 9-mer peptide derived from the AFP protein hAFP(542-550) (GVALQTMKQ). Identified as a potential A2.1-restricted peptide epitope from a computer analysis of the AFP sequence, hAFP(542-550) proved to have low binding affinity to A2.1, but slow off-kinetics. AFP-specific CTL- and IFN-gamma-producing cells recognize hAFP(542-550)-pulsed targets. Conversely, hAFP(542-550) peptide-generated T cells from both human lymphocyte cultures and A2.1/Kb transgenic mice recognized AFP-transfected targets in both cytotoxicity assays and cytokine release assays. These lines of evidence clearly demonstrate that AFP-reactive clones have not been deleted from the human T-cell repertoire and identify one immunodominant A2.1-restricted epitope. These findings also clearly establish AFP as a potential target for T-cell-based immunotherapy.
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Affiliation(s)
- L H Butterfield
- Division of Surgical Oncology, University of California Los Angeles Medical Center, University of California Los Angeles, 90095-1782, USA
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Vollmer CM, Eilber FC, Butterfield LH, Ribas A, Dissette VB, Koh A, Montejo LD, Lee MC, Andrews KJ, McBride WH, Glaspy JA, Economou JS. Alpha-fetoprotein-specific genetic immunotherapy for hepatocellular carcinoma. Cancer Res 1999; 59:3064-7. [PMID: 10397245] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/13/2023]
Abstract
The majority of human hepatocellular carcinomas overexpress alpha-fetoprotein (AFP). Two genetic immunization strategies were used to determine whether AFP could serve as a target for T-cell immune responses. Dendritic cells engineered to express AFP produced potent T-cell responses in mice, as evidenced by the generation of AFP-specific CTLs, cytokine-producing T cells, and protective immunity. AFP plasmid-based immunization generated less potent responses. These novel observations demonstrate that this oncofetal antigen can serve as an effective tumor rejection antigen. This provides a rational, gene therapy-based strategy for this disease, which is responsible for the largest number of cancer-related deaths worldwide.
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Affiliation(s)
- C M Vollmer
- Division of Surgical Oncology, University of California Los Angeles, 90095-1782, USA
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Abstract
In this article, Andrew Koh argues that non-judgemental care is a professional obligation with clear ethical and legal implications for nurses.
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Affiliation(s)
- A Koh
- St Bartholomew School of Nursing and Midwifery, City University, London
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Koh A. Racism: time to turn words into action. Nurs Times 1999; 95:30-1. [PMID: 10358599] [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: 04/13/2023]
Affiliation(s)
- A Koh
- St Bartholomew's Hospital, London
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