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Buttery SC, Lewis A, Alzetani A, Bolton CE, Curtis KJ, Dodd JW, Habib AM, Hussain A, Havelock T, Jordan S, Kallis C, Kemp SV, Kirk A, Lawson RA, Mahadeva R, Munavvar M, Naidu B, Rathinam S, Shackcloth M, Shah PL, Tenconi S, Hopkinson NS. Survival following lung volume reduction procedures: results from the UK Lung Volume Reduction (UKLVR) registry. BMJ Open Respir Res 2024; 11:e002092. [PMID: 38423954 PMCID: PMC10910650 DOI: 10.1136/bmjresp-2023-002092] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Accepted: 01/26/2024] [Indexed: 03/02/2024] Open
Abstract
INTRODUCTION Lung volume reduction surgery (LVRS) and endobronchial valve (EBV) placement can produce substantial benefits in appropriately selected people with emphysema. The UK Lung Volume Reduction (UKLVR) registry is a national multicentre observational study set up to support quality standards and assess outcomes from LVR procedures at specialist centres across the UK. METHODS Data were analysed for all patients undergoing an LVR procedure (LVRS/EBV) who were recruited into the study at participating centres between January 2017 and June 2022, including; disease severity and risk assessment, compliance with guidelines for selection, procedural complications and survival to February 2023. RESULTS Data on 541 patients from 14 participating centres were analysed. Baseline disease severity was similar in patients who had surgery n=244 (44.9%), or EBV placement n=219 (40.9%), for example, forced expiratory volume in 1 s (FEV1) 32.1 (12.1)% vs 31.2 (11.6)%. 89% of cases had discussion at a multidisciplinary meeting recorded. Median (IQR) length of stay postprocedure for LVRS and EBVs was 12 (13) vs 4 (4) days(p=0.01). Increasing age, male gender and lower FEV1%predicted were associated with mortality risk, but survival did not differ between the two procedures, with 50 (10.8%) deaths during follow-up in the LVRS group vs 45 (9.7%) following EBVs (adjusted HR 1.10 (95% CI 0.72 to 1.67) p=0.661) CONCLUSION: Based on data entered in the UKLVR registry, LVRS and EBV procedures for emphysema are being performed in people with similar disease severity and long-term survival is similar in both groups.
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Affiliation(s)
- S C Buttery
- National Heart and Lung Institute, Imperial College, London, UK
- Royal Brompton and Harefield Hospitals, Guy's and St Thomas' NHS Foundation Trust, London, UK
| | - A Lewis
- Department of Health Sciences, Brunel University London, Uxbridge, UK
| | - A Alzetani
- University Hospital Southampton, Southampton, UK
| | - C E Bolton
- NIHR Nottingham Biomedical Research Centre, University of Nottingham, Nottingham, UK
- Nottingham University Hospitals Trust, City Hospital Campus, Nottingham, UK
| | - K J Curtis
- University Hospitals Bristol and Weston, Bristol, UK
| | - J W Dodd
- Academic Respiratory Unit, University of Bristol, Bristol, UK
- North Bristol Lung Centre, North Bristol NHS Trust, Bristol, UK
| | - A M Habib
- New Cross Hospital, Royal Wolverhampton Hospitals NHS Trust, Wolverhampton, UK
| | - A Hussain
- Royal Brompton and Harefield Hospitals, Guy's and St Thomas' NHS Foundation Trust, London, UK
| | - T Havelock
- University Hospital Southampton, Southampton, UK
| | - S Jordan
- Royal Brompton and Harefield Hospitals, Guy's and St Thomas' NHS Foundation Trust, London, UK
| | - C Kallis
- National Heart and Lung Institute, Imperial College, London, UK
| | - S V Kemp
- National Heart and Lung Institute, Imperial College, London, UK
- Nottingham University Hospitals Trust, City Hospital Campus, Nottingham, UK
| | - A Kirk
- Department of Thoracic Surgery, West of Scotland Regional Heart and Lung Centre, Golden Jubilee National Hospital, West Dunbartonshire, Scotland, UK
| | - R A Lawson
- Northern General Hospital, Sheffield, UK
| | | | - M Munavvar
- Lancashire Teaching Hospitals NHS Trust, Preston, UK
| | - B Naidu
- Heartlands Hospital, Birmingham Teaching Hospitals, Birmingham, UK
| | - S Rathinam
- Thoracic Surgery, Glenfield Hospital, Leicester, UK
| | - M Shackcloth
- Liverpool Heart and Chest Hospital, Liverpool, UK
| | - P L Shah
- National Heart and Lung Institute, Imperial College, London, UK
- Royal Brompton and Harefield Hospitals, Guy's and St Thomas' NHS Foundation Trust, London, UK
| | - S Tenconi
- Northern General Hospital, Sheffield, UK
| | - N S Hopkinson
- National Heart and Lung Institute, Imperial College, London, UK
- Royal Brompton and Harefield Hospitals, Guy's and St Thomas' NHS Foundation Trust, London, UK
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Habib AM. Do business strategies and environmental, social, and governance (ESG) performance mitigate the likelihood of financial distress? A multiple mediation model. Heliyon 2023; 9:e17847. [PMID: 37483754 PMCID: PMC10362085 DOI: 10.1016/j.heliyon.2023.e17847] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 06/26/2023] [Accepted: 06/29/2023] [Indexed: 07/25/2023] Open
Abstract
This study explores the connection between business strategies, ESG performance, and the probability of bankruptcy. Using a sample comprising 1970 U.S. firm-year observations from 2016 to 2020, this study adopts several techniques to achieve its goals, including the partial least squares structural equation modeling (PLS-SEM) algorithm and additional analyses. The results demonstrate that a firm with a better cost leadership strategy has higher ESG performance. A sound cost leadership strategy and ESG performance negatively influence a firm's likelihood of financial distress. Using a mediating analysis model, we also find that financial and ESG performance mediate and mitigate the probability of experiencing financial distress through a cost leadership strategy, indicating that these are essential factors that cannot be ignored when mitigating bankruptcy probability. Financial performance also mediates and mitigates the probability of experiencing financial distress through the ESG path. This study adds to the existing body of knowledge by revealing the role of sound business strategies and ESG performance in mitigating the likelihood of financial distress, an under-explored topic. It also analyzes the mediation roles of financial and ESG performance to provide significant insights to companies' decision-makers in order to support them in their endeavors toward performance improvement and achieving best practices.
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Habib AM, Dalwai T. Does the Efficiency of a Firm’s Intellectual Capital and Working Capital Management Affect Its Performance? J Knowl Econ 2023. [PMCID: PMC10028330 DOI: 10.1007/s13132-023-01138-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Accepted: 02/21/2023] [Indexed: 07/25/2023]
Abstract
This study explores the efficiency of intellectual capital (ICE) and working capital management (WCME) in the GCC industrial sector and its potential impact on firm performance. The data were gathered from Standard & Poor’s database from 2015 to 2019. This study uses data envelopment analysis (DEA), regression analysis, and robustness tests to accomplish its aims. The results indicate that most firms do not employ their intellectual and working capital investments well and need improvement actions to achieve the best practices. The regression model results reveal that ICE and WCME significantly and positively influence firms’ performance. The results of this study support the resource-based, trade-off, and pecking order theories. The study findings have important implications for many stakeholders; for example, they would be helpful for firm decision-makers in managing their investments in intellectual and working capital to achieve the best practices and improve a firm's performance. In addition, the findings would be helpful for financiers, because high-performance firms are likely to have more reasonable valuations that facilitate debt financing. Moreover, the findings have noteworthy implications for trading procedures as investors aspire to attractive economic returns for their investments in corporations that pasture ICE and WCME issues. Additionally, these findings have important implications for employee job satisfaction and retention by improving IC management.
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Affiliation(s)
- Ahmed Mohamed Habib
- Independent Accounting and Finance Researcher, Independent Research, Zagazig, Egypt
| | - Tamanna Dalwai
- Department of Business and Accounting, Muscat College, Muscat, Oman
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Habib AM, Mourad N. The Influence of Environmental, Social, and Governance (ESG) Practices on US Firms’ Performance: Evidence from the Coronavirus Crisis. J Knowl Econ 2023. [PMCID: PMC10023311 DOI: 10.1007/s13132-023-01278-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Accepted: 02/24/2023] [Indexed: 07/25/2023]
Abstract
This study explores the influence of total and individual ESG practices and the coronavirus crisis on US firm performance (FP). A large and recent sample of 406 US firms that adopted ESG issues during 2016–2020 was used. This study uses the generalized least-squares (GLS) regression estimator, the dynamic analysis technique, and robustness tests. The results indicate that firms with heightened ESG practices have better performance measures. In most cases, the results suggest that firms with heightened environmental, social, and governance performances have better performance measures. The results suggest that the coronavirus crisis negatively affected FP measures. In addition, the analyses of the differences suggest significant distinctions in FP due to the coronavirus crisis. This study’s findings have important implications for stakeholders. Managers could benefit from the results of this examination by recognizing the status of ESG practices and FP before and during the coronavirus crisis and identifying the linkage between the fulfillment of ESG responsibilities and FP. This study provides noteworthy practical implications that could enable managers to develop strategies and policies for adopting and enhancing ESG practices to achieve the best performance. Furthermore, the results could influence trading processes as investors and financiers pursue attractive financial returns from investments in businesses concerned with ESG issues.
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Affiliation(s)
- Ahmed Mohamed Habib
- Independent Accounting and Finance Researcher, Independent Research, Zagazig, Egypt
| | - Nahia Mourad
- Faculty of Engineering and IT, British University in Dubai, Dubai, UAE
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Habib AM, Kayani UN. Evaluating the Super-Efficiency of Working Capital Management Using Data Envelopment Analysis: Does COVID-19 Matter? Oper. Res. Forum 2023; 4:40. [PMCID: PMC10147997 DOI: 10.1007/s43069-023-00217-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Accepted: 03/15/2023] [Indexed: 07/25/2023]
Abstract
This study evaluates the working capital management (WCM) super-efficiency in UAE firms and determines how the COVID-19 crisis may affect WCM super-efficiency from a statistical perspective. Data envelopment analysis (DEA), difference tests, and Tobit regression techniques are used. Integration of DEA with Tobit regression is required to recognize the potential statistical consequence of COVID-19 on the super-efficiency of WCM. The results show that WCM super-efficiency is moderate and requires decision-makers' corrective measures to attain best practices. The study results show no significant difference in WCM super-efficiency, and COVID-19 does not significantly influence WCM super-efficiency. The results would rouse decision-makers' interests, who would look into the firm's efficiency and weak spots. They would then take major steps to improve efficiency and achieve the best practices. Stakeholders such as managers, financiers, and investors may need these results to monitor how firms manage their assets and liabilities. We contribute to the literature by investigating and evaluating firms' WCM super-efficiency pre and post the COVID-19 pandemic employing a unique technique based on DEA super-efficiency and examining whether COVID-19 has affected WCM super-efficiency to extend the scope of knowledge and stressing the importance of sound WCM, especially in periods of economic distress.
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Affiliation(s)
- Ahmed Mohamed Habib
- Independent Accounting and Finance Researcher, Independent Research, Zagazig, Egypt
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Mourad N, Habib AM, Tharwat A. Appraising healthcare systems’ efficiency in facing COVID-19 through data envelopment analysis. 10 5267/j dsl 2021. [DOI: 10.5267/j.dsl.2021.2.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The healthcare system is a vital element for any community, as it extremely affects the socio-economic development of any country. The current study aims to assess the performance of the healthcare systems of the countries above fifty million citizens in facing the spread of the COVID-19 pandemic since late December 2019. For this purpose, seven scenarios were adopted via the DEA methodology with six variables, which are the number of medical practitioners (doctors and nurses), hospital beds, Conducted Covid-19 tests, affected cases, recovered cases, and death cases. To shed light on the relative efficiency of drivers, the Tobit analysis was used. Besides, the study carried out various statistical tests for the DEA models' findings to validate the choice of the variables and the obtained scores. The DEA results reveal that less than half of the considered countries are relatively efficient. Moreover, the Tobit regression analysis showed that the main impact on the efficiency scores was due to the number of affected and recovered cases. Finally, the results of the tests of Spearman, Mann-Whitney U, and Kruskal-Wallis H indicate the internal validity and robustness of the chosen DEA models. The current study findings raise important implications, which can be helpful for decision makers regarding continuous improvement of performance, in which the findings assert the importance of achieving the best practices regarding relative efficiency through the linkage between the healthcare systems’ resources, and the needed outputs.
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Habib AM, Shahwan TM. Measuring the operational and financial efficiency using a Malmquist data envelopment analysis: a case of Egyptian hospitals. BIJ 2020. [DOI: 10.1108/bij-01-2020-0041] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
PurposeThe efficient use of organizational resources is integral to the existence of prime firms. This study, using Malmquist data envelopment analysis (DEA), aims to assess in the level of operational and financial efficiency and its determinants for ensuring and sustaining excellent performance in 33 Egyptian private hospitals.Design/methodology/approachThis study adopted a Malmquist DEA approach to assess the changes in operational and financial efficiency in Egyptian hospitals. Tobit regression was also used to identify the significant variables affecting their efficiency. In addition, a sensitivity analysis is carried out for model validations.FindingsOut of 33 hospitals, 17 were found inefficient due to the decline in their technical efficiency. Moreover, the total value of the software programs and operational expenses and the total number of employees are common factors affecting both operational and financial efficiency. In addition, the number of physicians significantly affects the hospital's financial efficiency.Practical implicationsThe study sheds light on the value of using DEA to assess efficiency. DEA in the context of emerging economy such as Egypt's can be a useful tool for decision-makers and practitioners in identifying and addressing performance weaknesses and thus supports continuous improvement in performance.Originality/valueSeveral studies have adopted the DEA approach to assess the overall efficiency of hospitals in Europe and the United States. However, in the MENA region, these studies are uncommon. This study is thought to be one of the earliest attempts to assess hospitals' efficiency in Egypt.
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El-Sheikh MY, Habib AM, Gemeay AH, Zaki AB, Bargon J. Catalytic decomposition of hydrogen peroxide in presence of Ni(II)-ethanolamine complex ions sorbed on Dowex 50W resin. ACTA ACUST UNITED AC 2017. [DOI: 10.1051/jcp/1992892057] [Citation(s) in RCA: 9] [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: 11/14/2022]
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Rogers GJ, Tolhurst G, Ramzan A, Habib AM, Parker HE, Gribble FM, Reimann F. Electrical activity-triggered glucagon-like peptide-1 secretion from primary murine L-cells. J Physiol 2011; 589:1081-93. [PMID: 21224236 PMCID: PMC3060588 DOI: 10.1113/jphysiol.2010.198069] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2010] [Accepted: 12/31/2010] [Indexed: 01/21/2023] Open
Abstract
Glucagon like peptide 1 (GLP-1) based therapies are now widely used for the treatment of type 2 diabetes. Developing our understanding of intestinal GLP-1 release may facilitate the development of new therapeutics aimed at targeting the GLP-1 producing L-cells. This study was undertaken to characterise the electrical activity of primary L-cells and the importance of voltage gated sodium and calcium channels for GLP-1 secretion. Primary murine L-cells were identified and purified using transgenic mice expressing a fluorescent protein driven by the proglucagon promoter. Fluorescent L-cells were identified within primary colonic cultures for patch clamp recordings. GLP-1 secretion was measured from primary colonic cultures. L-cells purified by flow cytometry were used to measure gene expression by microarray and quantitative RT-PCR. Electrical activity in L-cells was due to large voltage gated sodium currents, inhibition of which by tetrodotoxin reduced both basal and glutamine-stimulated GLP-1 secretion. Voltage gated calcium channels were predominantly of the L-type, Q-type and T-type, by expression analysis, consistent with the finding that GLP-1 release was blocked both by nifedipine and ω-conotoxin MVIIC. We observed large voltage-dependent potassium currents, but only a small chromanol sensitive current that might be attributable to KCNQ1. GLP-1 release from primary L-cells is linked to electrical activity and activation of L-type and Q-type calcium currents. The concept of an electrically excitable L-cell provides a basis for understanding how GLP-1 release may be modulated by nutrient, hormonal and pharmaceutical stimuli.
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Affiliation(s)
- G J Rogers
- Cambridge Institute for Medical Research, Wellcome Trust/MRC Building, Addenbrooke's Hospital, Box 139, Hills Road, Cambridge CB2 0XY, UK
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Biswas PK, Christensen JP, Ahmed SSU, Barua H, Das A, Rahman MH, Giasuddin M, Hannan ASMA, Habib AM, Debnath NC. Risk factors for infection with highly pathogenic influenza A virus (H5N1) in commercial chickens in Bangladesh. Vet Rec 2009; 164:743-6. [PMID: 19525522 DOI: 10.1136/vr.164.24.743] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
A matched case-control study was carried out to identify risk factors for highly pathogenic avian influenza A virus (subtype H5N1) infection in commercial chickens in Bangladesh. A total of 33 commercial farms diagnosed with H5N1 before September 9, 2007, were enrolled as cases, and 99 geographically matched unaffected farms were enrolled as control farms. Farm data were collected using a pretested questionnaire, and analysed by matched-pair analysis and multivariate conditional logistic regression. Two factors independently and positively associated with H5N1 infection remained in the final model. They were 'farm accessible to feral and wild animals' (odds ratio [OR] 5.71, 95 per cent confidence interval [CI] 1.81 to 18.0, P=0.003) and 'footbath at entry to farm/shed' (OR 4.93, 95 per cent CI 1.61 to 15.1, P=0.005). The use of a designated vehicle for sending eggs to a vendor or market appeared to be a protective factor (OR 0.14, 95 per cent CI 0.02 to 0.88, P=0.036).
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Affiliation(s)
- P K Biswas
- Department of Microbiology, Veterinary and Animal Sciences University, Chittagong, Bangladesh.
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Parker HE, Habib AM, Rogers GJ, Gribble FM, Reimann F. Nutrient-dependent secretion of glucose-dependent insulinotropic polypeptide from primary murine K cells. Diabetologia 2009; 52:289-298. [PMID: 19082577 PMCID: PMC4308617 DOI: 10.1007/s00125-008-1202-x] [Citation(s) in RCA: 246] [Impact Index Per Article: 16.4] [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: 08/29/2008] [Accepted: 10/16/2008] [Indexed: 12/21/2022]
Abstract
AIMS/HYPOTHESIS Glucose-dependent insulinotropic polypeptide (GIP) is an incretin hormone with anti-apoptotic effects on the pancreatic beta cell. The aim of this study was to generate transgenic mice with fluorescently labelled GIP-secreting K cells and to use these to investigate pathways by which K cells detect nutrients. METHODS Transgenic mice were generated in which the GIP promoter drives the expression of the yellow fluorescent protein Venus. Fluorescent cells were purified by flow cytometry and analysed by quantitative RT-PCR. GIP secretion was assayed in primary cultures of small intestine. RESULTS Expression of Venus in transgenic mice was restricted to K cells, as assessed by immunofluorescence and measurements of the Gip mRNA and GIP protein contents of purified cells. K cells expressed high levels of mRNA for Kir6.2 (also known as Kcnj11), Sur1 (also known as Abcc8), Sglt1 (also known as Slc5a1), and of the G-protein-coupled lipid receptors Gpr40 (also known as Ffar1), Gpr119 and Gpr120. In primary cultures, GIP release was stimulated by glucose, glutamine and linoleic acid, and potentiated by forskolin plus 3-isobutyl-1-methylxanthine (IBMX), but was unaffected by the artificial sweetener sucralose. Secretion was half-maximal at 0.6 mmol/l glucose and partially mimicked by alpha-methylglucopyranoside, suggesting the involvement of SGLT1. Tolbutamide triggered secretion under basal conditions, whereas diazoxide suppressed responses in forskolin/IBMX. CONCLUSIONS/INTERPRETATION These transgenic mice and primary culture techniques provide novel opportunities to interrogate the mechanisms of GIP secretion. Glucose-triggered GIP secretion was SGLT1-dependent and modulated by K(ATP) channel activity but not determined by sweet taste receptors. Synergistic stimulation by elevated cAMP and glucose suggests that targeting appropriate G-protein-coupled receptors may provide opportunities to modulate GIP release in vivo.
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Affiliation(s)
- H E Parker
- Cambridge Institute for Medical Research, Wellcome Trust/MRC Building, Addenbrooke's Hospital, Hills Road, Cambridge CB2 0XY, UK
| | - A M Habib
- Cambridge Institute for Medical Research, Wellcome Trust/MRC Building, Addenbrooke's Hospital, Hills Road, Cambridge CB2 0XY, UK
| | - G J Rogers
- Cambridge Institute for Medical Research, Wellcome Trust/MRC Building, Addenbrooke's Hospital, Hills Road, Cambridge CB2 0XY, UK
| | - F M Gribble
- Cambridge Institute for Medical Research, Wellcome Trust/MRC Building, Addenbrooke's Hospital, Hills Road, Cambridge CB2 0XY, UK
| | - F Reimann
- Cambridge Institute for Medical Research, Wellcome Trust/MRC Building, Addenbrooke's Hospital, Hills Road, Cambridge CB2 0XY, UK
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Vincent JL, Habib AM, Verdant C, Bruhn A. Sepsis diagnosis and management: work in progress. Minerva Anestesiol 2006; 72:87-96. [PMID: 16493385] [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: 05/06/2023]
Abstract
Severe sepsis is a common disease process in the critically ill and is associated with substantial morbidity and mortality. Continuing research has provided considerable insight into the pathophysiology of sepsis over recent years, enabling various aspects of the sepsis response to be targeted. Discoveries related to the link between coagulation and inflammation have been particularly exciting, leading to the development of recombinant activated protein C. This review will discuss current definitions of sepsis, describe new approaches to classification and diagnosis of patients with sepsis, present recommendations for management, and briefly highlight areas of ongoing and future research.
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Affiliation(s)
- J L Vincent
- Deparment of Intensive Care, Erasme Hospital, Free University of Brussels, Brussels, Belgium.
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Gameiro A, Reimann F, Habib AM, O'Malley D, Williams L, Simpson AK, Gribble FM. The neurotransmitters glycine and GABA stimulate glucagon-like peptide-1 release from the GLUTag cell line. J Physiol 2005; 569:761-72. [PMID: 16223757 PMCID: PMC1464262 DOI: 10.1113/jphysiol.2005.098962] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.1] [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: 12/19/2022] Open
Abstract
The incretin hormone, glucagon-like peptide-1 (GLP-1) is released from intestinal L-cells following food ingestion. Its secretion is triggered by a range of nutrients, including fats, carbohydrates and proteins. We reported previously that Na(+)-dependent glutamine uptake triggered electrical activity and GLP-1 release from the L-cell model line GLUTag. However, whereas alanine also triggered membrane depolarization and GLP-1 secretion, the response was Na+ independent. A range of alanine analogues, including d-alanine, beta-alanine, glycine and l-serine, but not d-serine, triggered similar depolarizing currents and elevation of intracellular [Ca2+], a sensitivity profile suggesting the involvement of glycine receptors. In support of this idea, glycine-induced currents and GLP-1 release were blocked by strychnine, and currents showed a 58.5 mV shift in reversal potential per 10-fold change in [Cl-], consistent with the activation of a Cl(-)-selective current. GABA, an agonist of related Cl- channels, also triggered Cl- currents and secretion, which were sensitive to picrotoxin. GABA-triggered [Ca2+]i increments were abolished by bicuculline and partially impaired by (1,2,5,6-tetrahydropyridine-4-yl)methylphosphinic acid (TPMPA), suggesting the involvement of both GABA(A) and GABA(C) receptors. Expression of GABA(A), GABA(C) and glycine receptor subunits was confirmed by RT-PCR. Glycine-triggered GLP-1 secretion was impaired by bumetanide but not bendrofluazide, suggesting that a high intracellular [Cl-] maintained by Na(+)-K(+)-2Cl- cotransporters is necessary for the depolarizing response to glycine receptor ligands. Our results suggest that GABA and glycine stimulate electrical activity and GLP-1 release from GLUTag cells by ligand-gated ion channel activation, a mechanism that might be important in responses to endogenous ligands from the enteric nervous system or dietary sources.
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MESH Headings
- Action Potentials/drug effects
- Animals
- Calcium/metabolism
- Cell Line, Tumor
- Chlorides/metabolism
- Dose-Response Relationship, Drug
- GABA Antagonists/pharmacology
- Glucagon-Like Peptide 1/metabolism
- Glycine/pharmacology
- Ion Channel Gating/drug effects
- Mice
- Neurotransmitter Agents/pharmacology
- RNA, Messenger/metabolism
- Receptors, GABA/drug effects
- Receptors, GABA/genetics
- Receptors, GABA/metabolism
- Receptors, GABA-A/drug effects
- Receptors, GABA-A/genetics
- Receptors, GABA-A/metabolism
- Receptors, Glycine/drug effects
- Receptors, Glycine/genetics
- Receptors, Glycine/metabolism
- Sodium Potassium Chloride Symporter Inhibitors/pharmacology
- Sodium-Potassium-Chloride Symporters/drug effects
- Sodium-Potassium-Chloride Symporters/metabolism
- Strychnine/pharmacology
- gamma-Aminobutyric Acid/pharmacology
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Affiliation(s)
- A Gameiro
- Wellcome Trust/MRC Building, Addenbrooke's Hospital, Hills Road, Cambridge CB2 2XY, UK
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Reimann F, Maziarz M, Flock G, Habib AM, Drucker DJ, Gribble FM. Characterization and functional role of voltage gated cation conductances in the glucagon-like peptide-1 secreting GLUTag cell line. J Physiol 2004; 563:161-75. [PMID: 15611035 PMCID: PMC1665554 DOI: 10.1113/jphysiol.2004.076414] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [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: 01/14/2023] Open
Abstract
Glucagon-like peptide-1 (GLP-1) is released from intestinal L-cells in response to nutrient ingestion. It is currently under therapeutic evaluation because it enhances insulin secretion in type 2 diabetes. Previous studies using the GLP-1 secreting cell line GLUTag have shown that the cells are electrically active, and that the action potential frequency is regulated by nutrients. In this study we characterize voltage gated currents underlying this electrical activity and correlate the electrophysiological findings with gene expression determined by microarrays. Whole cell voltage clamp experiments designed to separate different ionic components revealed rapidly inactivating sodium currents sensitive to tetrodotoxin, calcium currents sensitive to nifedipine and omega-conotoxin GVIA, and sustained as well as rapidly inactivating potassium currents, which were sensitive to TEA and 4-AP, respectively. In perforated patch experiments we also observed hyperpolarization-activated currents which were inhibited by ZD7288. The amplitude of the sodium current was approximately 10 times that of the other depolarizing currents and tetrodotoxin abolished action potential firing. In secretion experiments, however, nifedipine, but not tetrodotoxin, omega-conotoxin GVIA or ZD7288, inhibited glucose-induced GLP-1 release. Consistent with this finding, the intracellular Ca2+ response to glucose was impaired by nifedipine but not by tetrodotoxin. Thus, in GLUTag cells, GLP-1 release is not dependent on the firing of Na+-carrying action potentials but requires membrane depolarization and Ca2+ entry through L-type Ca2+ channels. Understanding the characteristics of the currents and the molecular identification of the underlying channels in GLP-1 secreting cells might facilitate the development of agents to enhance GLP-1 secretion in vivo.
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Affiliation(s)
- F Reimann
- Cambridge Institute for Medical Research, University of Cambridge, Department of Clinical Biochemistry, Wellcome Trust/MRC Building, Addenbrooke's Hospital, Hills Road, Cambridge CB2 2XY, UK.
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Nagi HK, Habib AM, Omar SH, Zakaria AY. Effect of noninvasive ventilation on pulmonary gas exchange in chronic obstructive pulmonary disease. Crit Care 2002. [PMCID: PMC3333705 DOI: 10.1186/cc1746] [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] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Affiliation(s)
- HK Nagi
- Critical Care Medicine Department, Cairo University, Egypt
| | - AM Habib
- Critical Care Medicine Department, Cairo University, Egypt
| | - SH Omar
- Critical Care Medicine Department, Cairo University, Egypt
| | - AY Zakaria
- Critical Care Medicine Department, Cairo University, Egypt
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Mahmood T, Saridogan E, Smutna S, Habib AM, Djahanbakhch O. The effect of ovarian steroids on epithelial ciliary beat frequency in the human Fallopian tube. Hum Reprod 1998; 13:2991-4. [PMID: 9853843 DOI: 10.1093/humrep/13.11.2991] [Citation(s) in RCA: 103] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Using a method that detects variations in light intensity we have studied the effect of ovarian steroids on human Fallopian tube epithelial ciliary beat frequency in vitro. We have found that baseline ciliary beat frequency averages between 5-6 Hz. Cilia from ampullary segments of the Fallopian tube beat significantly faster (5.4 Hz+/-0.2) than those from fimbrial segments (4.8 Hz+/-0.2). There was no significant difference in baseline ciliary beat frequency at any other anatomical site in the Fallopian tube. Incubation with progesterone (10 micromol/l) suppresses human Fallopian tube epithelial ciliary beat frequency by 40-50%. This inhibition was observed at similar magnitudes in all Fallopian tubes studied irrespective of anatomical site. Progesterone-induced reductions in ciliary beat frequency were concentration dependent and prevented by the progesterone receptor antagonist mifepristone (RU486). Oestradiol alone (10 micromol/l) had no effect on ciliary beat frequency at any anatomical site in the Fallopian tube but did prevent the reduction in ciliary beat frequency seen with progesterone when tissues were incubated with these two steroids together.
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Affiliation(s)
- T Mahmood
- Academic Department of Obstetrics, Gynaecology and Reproductive Physiology, St Bartholomew's and the Royal London School of Medicine, The Royal London Hospital, Whitechapel, UK
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