163 results on '"Burnand KG"'
Search Results
2. Nox activator 1: a potential target for modulation of vascular reactive oxygen species in atherosclerotic arteries.
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Niu XL, Madamanchi NR, Vendrov AE, Tchivilev I, Rojas M, Madamanchi C, Brandes RP, Krause KH, Humphries J, Smith A, Burnand KG, Runge MS, Niu, Xi-Lin, Madamanchi, Nageswara R, Vendrov, Aleksandr E, Tchivilev, Igor, Rojas, Mauricio, Madamanchi, Chaitanya, Brandes, Ralph P, and Krause, Karl-Heinz
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- 2010
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3. Successful thrombolysis of a symptomatic neonatal aortic thrombosis associated with hypernatraemic dehydration - case report and literature review.
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Morales JP, Sabharwal T, Tibby SM, and Burnand KG
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- 2008
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4. Mutations in FOXC2 are strongly associated with primary valve failure in veins of the lower limb.
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Mellor RH, Brice G, Stanton AW, French J, Smith A, Jeffery S, Levick JR, Burnand KG, Mortimer PS, Lymphoedema Research Consortium, Mellor, Russell H, Brice, Glen, Stanton, Anthony W B, French, Jane, Smith, Alberto, Jeffery, Steve, Levick, J Rodney, Burnand, Kevin G, and Mortimer, Peter S
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- 2007
5. Endothelial progenitor cells are recruited into resolving venous thrombi.
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Modarai B, Burnand KG, Sawyer B, and Smith A
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- 2005
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6. What can wound fluids tell us about the venous ulcer microenvironment?
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Drinkwater SL, Smith A, and Burnand KG
- Abstract
Research into the healing of venous leg ulcers is increasing as they are a common problem. The wound fluid bathing an ulcer is thought to reflect the wound microenvironment, and the properties of wound fluids have been studied in attempts to find ways to promote healing. After a brief summary of normal wound healing, this article reviews some of the research that has been carried out on venous ulcer wound fluid, with respect to its biochemistry, proteolytic nature, growth factor profile, and effects on cell cultures. Some of the problems and pitfalls inherent in performing and interpreting wound fluid studies are discussed. Finally, a proposal is made for standardizing research on wound fluids that would improve comparisons between different studies. [ABSTRACT FROM AUTHOR]
- Published
- 2002
7. Images in cardiovascular medicine. Complications after endoluminal stent grafting of a thoracic mycotic aneurysm.
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Saha P, Burnand KG, Patel SD, Waltham M, Saha, Prakash, Burnand, Kevin G, Patel, Sanjay D, and Waltham, Matt
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- 2008
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8. Deep-vein thrombosis in long-haul flights
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Burnand, KG, McGuinness, CL, and Smith, A
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- 2001
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9. Hematopoietic progenitor cells and restenosis after carotid endarterectomy.
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Patel SD, Humphries J, Mattock K, Wadoodi A, Modarai B, Ahmad A, Burnand KG, Waltham M, and Smith A
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- AC133 Antigen, Aged, Aged, 80 and over, Antigens, CD blood, Antigens, CD34 blood, Carotid Stenosis pathology, Carotid Stenosis surgery, Endothelium, Vascular injuries, Endothelium, Vascular pathology, Female, Glycoproteins blood, Hematopoietic Stem Cells pathology, Humans, Male, Middle Aged, Peptides blood, Carotid Stenosis blood, Chemokine CXCL12 blood, Endarterectomy, Carotid, Endothelium, Vascular metabolism, Hematopoietic Stem Cells metabolism, Regeneration
- Abstract
Background and Purpose: Hematopoietic progenitor cells (HPCs) may attenuate the response to vascular injury by maintaining endothelial integrity and function. Our aim was to determine whether circulating HPC number and function correlate with restenosis after carotid endarterectomy., Methods: HPC number (CD34(+)/CD133(+) cells), early colony-forming units, migratory capacity, and senescence were analyzed in blood collected preoperatively, 1 day, and 6 weeks postoperatively. Mobilizing cytokine levels were also measured. Stenosis was assessed by duplex scanning., Results: HPC numbers (P<0.001) and early colony-forming unit count (P=0.001) fell rapidly 24 hours postoperatively. Restenosis at 6 months correlated negatively with the magnitude of postoperative falls in HPC numbers (R=-0.38, P=0.013) and early colony-forming unit counts (R=-0.42, P=0.008). The migratory capacity of preoperative HPCs correlated negatively with restenosis (R=-0.48, P=0.007). Preoperative SDF1 levels correlated with falls in HPC number (R=0.42, P=0.044) and early colony-forming unit counts (R=0.56, P=0.004)., Conclusions: HPC function appears to be linked to the development of carotid artery restenosis after endarterectomy. These data support the concept that HPCs have a role in regulating remodeling of the injured arterial wall.
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- 2012
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10. Mutations in FOXC2 in humans (lymphoedema distichiasis syndrome) cause lymphatic dysfunction on dependency.
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Mellor RH, Tate N, Stanton AW, Hubert C, Mäkinen T, Smith A, Burnand KG, Jeffery S, Levick JR, and Mortimer PS
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- Adult, Biopsy, Eyelashes abnormalities, Eyelashes diagnostic imaging, Eyelashes pathology, Female, Foot, Forearm, Germ-Line Mutation, Humans, Lymphedema diagnostic imaging, Lymphography, Male, Middle Aged, Stress, Physiological, Young Adult, Forkhead Transcription Factors genetics, Gravitation, Lymphatic System pathology, Lymphatic System physiology, Lymphedema genetics, Lymphedema pathology
- Abstract
Background: Human lymphoedema distichiasis syndrome (LDS) results from germline mutations in transcription factor FOXC2. In a mouse model, lack of lymphatic and venous valves is observed plus abnormal smooth muscle cell recruitment to initial lymphatics. We investigated the mechanism of lymphoedema in humans with FOXC2 mutations, specifically the effect of gravitational forces on dermal lymphatic function., Methods: We performed (1) quantitative fluorescence microlymphangiography (FML) on the skin of the forearm (non-swollen region) at heart level, and the foot (swollen region) below heart level (dependent) and then at heart level, and (2) immunohistochemical staining of microlymphatics in forearm and foot skin biopsies, using antibodies to podoplanin, LYVE-1 and smooth muscle actin., Results: FML revealed a marked reduction in fluid uptake by initial lymphatics in the LDS foot during dependency, yet normal uptake (similar to controls) in the same foot at heart level and in LDS forearms. In control subjects, dependency did not impair initial lymphatic filling. Immunohistochemical microlymphatic density in forearm and foot did not differ between LDS and controls., Conclusions: FOXC2 mutations cause a functional failure of dermal initial lymphatics during gravitational stress (dependency), but not hypoplasia. The results reveal a pathophysiological mechanism contributing to swelling in LDS., (Copyright © 2011 S. Karger AG, Basel.)
- Published
- 2011
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11. Lymphatic dysfunction, not aplasia, underlies Milroy disease.
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Mellor RH, Hubert CE, Stanton AW, Tate N, Akhras V, Smith A, Burnand KG, Jeffery S, Mäkinen T, Levick JR, and Mortimer PS
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- Adult, Aged, Case-Control Studies, Dextrans, Female, Fluorescein-5-isothiocyanate analogs & derivatives, Fluorescent Dyes, Foot, Forearm, Humans, Immunohistochemistry, Lymphatic System diagnostic imaging, Lymphatic System pathology, Lymphedema genetics, Lymphedema pathology, Lymphedema physiopathology, Lymphography methods, Male, Middle Aged, Mutation, Ultrasonography, Doppler, Color, Vascular Endothelial Growth Factor Receptor-3 genetics, Vesicular Transport Proteins metabolism, Young Adult, Lymphatic System physiopathology, Lymphedema etiology
- Abstract
Objective: Milroy disease is an inherited autosomal dominant lymphoedema caused by mutations in the gene for vascular endothelial growth factor receptor-3 (VEGFR-3, also known as FLT4). The phenotype has to date been ascribed to lymphatic aplasia. We further investigated the structural and functional defects underlying the phenotype in humans., Methods: The skin of the swollen foot and the non-swollen forearm was examined by (i) fluorescence microlymphangiography, to quantify functional initial lymphatic density in vivo; and (ii) podoplanin and LYVE-1 immunohistochemistry of biopsies, to quantify structural lymphatic density. Leg vein function was assessed by colour Doppler duplex ultrasound., Results: Milroy patients exhibited profound (86-91%) functional failure of the initial lymphatics in the foot; the forearm was unimpaired. Dermal lymphatics were present in biopsies but density was reduced by 51-61% (foot) and 26-33% (forearm). Saphenous venous reflux was present in 9/10 individuals with VEGFR3 mutations, including two carriers., Conclusion: We propose that VEGFR3 mutations in humans cause lymphoedema through a failure of tissue protein and fluid absorption. This is due to a profound functional failure of initial lymphatics and is not explained by microlymphatic hypoplasia alone. The superficial venous valve reflux indicates the dual role of VEGFR-3 in lymphatic and venous development.
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- 2010
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12. The role of endothelial cells and their progenitors in intimal hyperplasia.
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Patel SD, Waltham M, Wadoodi A, Burnand KG, and Smith A
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- Animals, Cardiovascular Diseases physiopathology, Coronary Restenosis etiology, Endothelial Cells metabolism, Endothelium, Vascular metabolism, Humans, Hyperplasia complications, Hyperplasia physiopathology, Stem Cells metabolism, Tunica Intima pathology, Coronary Restenosis prevention & control, Hyperplasia prevention & control, Stem Cell Transplantation methods
- Abstract
Intimal hyperplasia leading to restenosis is the major process that limits the success of cardiovascular intervention. The emergence of vascular progenitor cells and, in particular, endothelial progenitor cells has led to great interest in their potential therapeutic value in preventing intimal hyperplasia. We review the mechanism of intimal hyperplasia and highlight the important attenuating role played by a functional endothelium. The role of endothelial progenitor cells in maintaining endothelial function is reviewed and we describe how reduced progenitor cell number and function and reduced endothelial function lead to an increased risk of intimal hyperplasia. We review other potential sources of endothelial cells, including monocytes, mesenchymal stem cells and tissue resident stem cells. Endothelial progenitor cells have been used in clinical trials to reduce the risk of restenosis with varied success. Progenitor cells have huge therapeutic potential to prevent intimal hyperplasia but a more detailed understanding of vascular progenitor cell biology is necessary before further clinical trials are commenced.
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- 2010
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13. Monocyte urokinase-type plasminogen activator up-regulation reduces thrombus size in a model of venous thrombosis.
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Humphries J, Gossage JA, Modarai B, Burnand KG, Sisson TH, Murdoch C, and Smith A
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- Adenoviridae genetics, Animals, Cell Movement, Cell Survival, Cells, Cultured, Cytokines metabolism, Disease Models, Animal, Fibrinolysis, Fluorescent Dyes, Genetic Vectors, HLA Antigens analysis, Humans, Inflammation Mediators metabolism, Macrophages enzymology, Macrophages immunology, Mice, Mice, SCID, Organic Chemicals, Plasminogen Activator Inhibitor 1 metabolism, Plasminogen Activator Inhibitor 2 metabolism, Receptors, Urokinase Plasminogen Activator metabolism, Staining and Labeling methods, Time Factors, Transduction, Genetic, Up-Regulation, Urokinase-Type Plasminogen Activator genetics, Venous Thrombosis blood, Venous Thrombosis enzymology, Venous Thrombosis genetics, Genetic Therapy, Macrophages transplantation, Urokinase-Type Plasminogen Activator metabolism, Venous Thrombosis therapy
- Abstract
Background: Our previous studies showed that the direct injection of an adenovirus construct expressing urokinase-type plasminogen activator (uPA) into experimental venous thrombi significantly reduces thrombus weight. The systemic use of adenovirus vectors is limited by inherent hepatic tropism and inflammatory response. As macrophages are recruited into venous thrombi, it is reasonable to speculate that these cells could be used to target the adenovirus uPA (ad-uPA) gene construct to the thrombus. The aims of this study were to determine whether macrophages transduced with ad-uPA have increased fibrinolytic activity and whether systemic injection of transduced cells could be used to target uPA expression to the thrombus and reduce its size., Methods: The effect of up-regulating uPA was examined in an immortalized macrophage cell line (MM6) and macrophages differentiated from human blood monocyte-derived macrophages (HBMMs). Cells were infected with ad-uPA or blank control virus (ad-blank). Fibrinolytic mediator expression, cell viability, and cytokine expression were measured by activity assays and enzyme-linked immunosorbent assays. Monocyte migration was measured using a modified Boyden chamber assay. A model of venous thrombosis was developed and characterized in mice with severe combined immunodeficiency (SCID). This model was used to study whether systemically administered macrophages over-expressing uPA reduced thrombus size. Uptake of HBMMs into the thrombus induced in these mice was confirmed by a combination of PKH2-labeled cell tracking and colocalization with human leukocyte antigen (HLA) by immunohistology., Results: Compared with ad-blank, treated HBMMs transduction with ad-uPA increased uPA production by >1000-fold (P = .003), uPA activity by 150-fold (P = .0001), and soluble uPA receptor (uPAR) by almost twofold (P = .043). Expression of plasminogen activator inhibitor (PAI-1) and PAI-2 was decreased by about twofold (P = .011) and threefold (P = .005), respectively. Up-regulation of uPA had no effect on cell viability or inflammatory cytokine production compared with ad-blank or untreated cells. Ad-uPA transduction increased the migration rate of HBMMs (about 20%, P = .03) and MM6 cells (>twofold, P = .005) compared with ad-blank treated controls. Human macrophage recruitment into the mouse thrombus was confirmed by the colocalization of HLA with the PKH2-marked cells. Systemic injection of uPA-up-regulated HBMMs reduced thrombus weight by approximately 20% compared with ad-blank (P = .038) or sham-treated controls (P = .0028)., Conclusion: Transduction of HBBM with ad-uPA increases their fibrinolytic activity. Systemic administration of uPA up-regulated HBBMs reduced thrombus size in an experimental model of venous thrombosis. Alternative methods of delivering fibrinolytic agents are worth exploring.
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- 2009
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14. Quality of life after surgical reduction for severe primary lymphoedema of the limbs and genitalia.
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Ogunbiyi SO, Modarai B, Smith A, and Burnand KG
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- Adolescent, Adult, Child, Female, Humans, Male, Middle Aged, Prospective Studies, Retrospective Studies, Treatment Outcome, Young Adult, Genital Diseases, Female surgery, Genital Diseases, Male surgery, Lymphedema surgery, Quality of Life
- Abstract
Background: The aim was to assess the quality of life (QoL) of patients who had surgery for primary lymphoedema., Methods: A QoL questionnaire was administered to patients who had surgery between 1981 and 2003 (retrospective group) and between 2003 and 2006 (prospective group)., Results: The response rate was 70.3 per cent (109 of 155 patients): 88 patients had limb reduction (78, retrospective; ten, prospective) and 21 had genital reduction (13, retrospective; eight, prospective). Forty-nine patients (63 per cent) who had limb reduction studied retrospectively reported satisfaction with the procedure and most of these would opt for surgery again. In the prospectively studied group, nine of ten patients reported improved limbs, and seven would opt for surgery again. Nineteen of 21 patients who had genital reduction would choose to have surgery again if needed (11 of the retrospectively assessed group and all of the prospective group). Patients' perception that surgery was worthwhile was greater in both of the prospectively assessed groups (P = 0.013)., Conclusion: Surgery for severe lymphoedema improved QoL at early assessment. This, however, may not be sustained. Genital reduction appeared to provide greater benefit than limb reduction.
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- 2009
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15. Hereditary palmoplantar keratoderma associated with primary (congenital) lymphedema.
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Ogunbiyi SO, Deguara J, Moss C, and Burnand KG
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- Child, Preschool, Female, Humans, Keratoderma, Palmoplantar congenital, Lymphedema congenital, Male, Pedigree, Prognosis, Keratoderma, Palmoplantar complications, Keratoderma, Palmoplantar genetics, Lymphedema complications, Lymphedema genetics
- Abstract
The palmoplantar keratodermas are a heterogenous group of hereditary disorders of keratinization. They are characterized by epidermal thickening and a yellow waxy appearance of the palms and soles. Genetic studies have linked various forms of palmoplantar keratoderma to markers on chromosomes one, twelve, and seventeen, and several genes have been identified. Primary lymphedema is occasionally present at birth (congenital lymphedema or Milroy's disease), but more commonly develops at puberty (lymphedema praecox). Genetic studies have linked various autosomal dominant forms of primary lymphedema (Milroy's disease and lymphedema distichiasis), to genes on chromosomes five and sixteen respectively. We report a case of palmoplantar keratoderma in a child with congenital lymphedema. To our knowledge, this has not been previously described and may represent a new phenotype for future genetic study.
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- 2009
16. The monocyte/macrophage as a therapeutic target in atherosclerosis.
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Saha P, Modarai B, Humphries J, Mattock K, Waltham M, Burnand KG, and Smith A
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- Animals, Anti-Inflammatory Agents therapeutic use, Antioxidants therapeutic use, Atherosclerosis metabolism, Cholesterol metabolism, Clinical Trials as Topic, Drug Delivery Systems, Extracellular Matrix metabolism, Humans, Inflammation metabolism, Macrophages metabolism, Models, Biological, Monocytes metabolism, Oxidative Stress immunology, Atherosclerosis drug therapy, Atherosclerosis immunology, Macrophages immunology, Monocytes immunology
- Abstract
It is now clear that the monocyte/macrophage has a crucial role in the development of atherosclerosis. This cell appears to be involved in all stages of atherosclerotic plaque development and is increasingly seen as a candidate for therapeutic intervention and as a potential biomarker of disease progression and response to therapy. The main mechanisms related to the activity of the monocyte/macrophage that have been targeted for therapy are those that facilitate recruitment, cholesterol metabolism, inflammatory activity and oxidative stress. There is also increasing evidence that there is heterogeneity within the monocyte/macrophage population, which may have important implications for plaque development and regression. A better insight into how specific phenotypes may influence plaque progression should facilitate the development of novel methods of imaging and more refined treatments.
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- 2009
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17. Human tribbles homologue 2 is expressed in unstable regions of carotid plaques and regulates macrophage IL-10 in vitro.
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Deng J, James CH, Patel L, Smith A, Burnand KG, Rahmoune H, Lamb JR, and Davis B
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- Antigens, CD metabolism, Antigens, Differentiation, Myelomonocytic metabolism, Calcium-Calmodulin-Dependent Protein Kinases, Carotid Artery Diseases surgery, Cell Cycle Proteins genetics, Cell Cycle Proteins metabolism, Cells, Cultured, Endarterectomy, Carotid, Gene Expression Regulation drug effects, Humans, Interleukin-10 genetics, Intracellular Signaling Peptides and Proteins genetics, Intracellular Signaling Peptides and Proteins physiology, Lipoproteins, LDL pharmacology, Macrophages drug effects, Protein Serine-Threonine Kinases genetics, Protein Serine-Threonine Kinases metabolism, RNA, Messenger genetics, Repressor Proteins genetics, Repressor Proteins metabolism, Carotid Artery Diseases metabolism, Interleukin-10 biosynthesis, Intracellular Signaling Peptides and Proteins metabolism, Macrophages metabolism
- Abstract
Mammalian orthologues of the Drosophila tribbles protein (Trb1, Trb2 and Trb3) are a recently described family of signalling molecules that regulate gene expression by modulation of protein kinase signalling pathways. In the present study, a screen for mRNA species specifically regulated in vulnerable regions of human atherosclerotic plaque demonstrated the up-regulation of both Trb1 and Trb2, the latter by more than 8-fold. In vitro experiments in primary human monocyte-derived macrophages showed that Trb2 expression was up-regulated by treatment with oxidized LDL (low-density lipoprotein), and that expression of recombinant Trb2 specifically reduced macrophage levels of IL-10 (interleukin-10) mRNA. Our results thus identify Trb2 as a highly regulated gene in vulnerable atherosclerotic lesions, and demonstrate inhibition of macrophage IL-10 biosynthesis as a potential pro-inflammatory consequence of high Trb2 expression, which may contribute to plaque instability.
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- 2009
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18. Adenovirus-mediated VEGF gene therapy enhances venous thrombus recanalization and resolution.
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Modarai B, Humphries J, Burnand KG, Gossage JA, Waltham M, Wadoodi A, Kanaganayagam GS, Afuwape A, Paleolog E, and Smith A
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- Animals, Cell Line, Disease Models, Animal, Genes, Reporter, Green Fluorescent Proteins metabolism, Humans, Macrophages metabolism, Male, Mice, Mice, SCID, Rats, Rats, Wistar, Time Factors, Vascular Endothelial Growth Factor A genetics, Vascular Endothelial Growth Factor Receptor-2 metabolism, Venous Thrombosis genetics, Venous Thrombosis metabolism, Venous Thrombosis pathology, Adenoviridae genetics, Gene Transfer Techniques, Genetic Therapy methods, Genetic Vectors, Macrophages transplantation, Vascular Endothelial Growth Factor A metabolism, Venous Thrombosis therapy
- Abstract
Objective: Rapid thrombus recanalization reduces the incidence of post-thrombotic complications. This study aimed to discover whether adenovirus-mediated transfection of the vascular endothelial growth factor gene (ad.VEGF) enhanced thrombus recanalization and resolution., Methods and Results: In rats, thrombi were directly injected with either ad.VEGF (n=40) or ad.GFP (n=37). Thrombi in SCID mice (n=12) were injected with human macrophages transfected with ad.VEGF or ad.GFP. Thrombi were analyzed at 1 to 14 days. GFP was found mainly in the vein wall and adventitia by 3 days, but was predominantly found in cells within the body of thrombus by day 7. VEGF levels peaked at 4 days (376+/-299 pg/mg protein). Ad.VEGF treatment reduced thrombus size by >50% (47.7+/-5.1 mm(2) to 22.0+/-4.0 mm(2), P=0.0003) and increased recanalization by >3-fold (3.9+/-0.69% to 13.6+/-4.1%, P=0.024) compared with controls. Ad.VEGF treatment increased macrophage recruitment into the thrombus by more than 50% (P=0.002). Ad.VEGF-transfected macrophages reduced thrombus size by 30% compared with controls (12.3+/-0.89 mm(2) to 8.7+/-1.4 mm(2), P=0.04) and enhanced vein lumen recanalization (3.39+/-0.34% to 5.07+/-0.57%, P=0.02)., Conclusions: Treatment with ad.VEGF enhanced thrombus recanalization and resolution, probably as a consequence of an increase in macrophage recruitment.
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- 2008
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19. Systemic administration of heparin intraoperatively in patients undergoing open repair of leaking abdominal aortic aneurysm may be beneficial and does not cause problems.
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Chinien G, Waltham M, Abisi S, Smith A, Taylor P, and Burnand KG
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- Age Factors, Aged, Aged, 80 and over, Aortic Aneurysm, Abdominal mortality, Aortic Rupture mortality, Blood Vessel Prosthesis Implantation methods, Drug Administration Schedule, Female, Humans, Intraoperative Complications etiology, Intraoperative Complications mortality, Male, Middle Aged, Multivariate Analysis, Postoperative Complications etiology, Postoperative Complications mortality, Prospective Studies, Treatment Outcome, Anticoagulants administration & dosage, Aortic Aneurysm, Abdominal surgery, Aortic Rupture surgery, Blood Vessel Prosthesis Implantation mortality, Heparin administration & dosage, Thrombectomy mortality
- Abstract
The aim of this study was to investigate whether intravenous heparin administration was associated with a reduction in perioperative mortality and late distal thrombectomy in patients with ruptured abdominal aortic aneurysms (AAAs). One hundred thirty-one patients had repair of ruptured AAA between January 1999 and January 2004. Sixty-three received heparin according to the consultant's preference at the time of the operation. Data were prospectively collected, and multivariate analysis was performed for independent predictive factors. Thirty-day mortality was 29%. Patients receiving heparin had lower perioperative mortality (16% vs 42%; p= .001). Heparin administration was not associated with increased hemorrhage or transfusion. Multivariate analysis confirmed that heparin administration was independently predictive of survival (p= .036). Other factors found to reduce survival were age (p= .023), smoking (p= .042), and systolic blood pressure (<100 mmHg) at presentation (p= .045). Fewer patients had thrombectomy after heparin (8% vs 12%), but this was not statistically significant. Perioperative complications were similar in both groups. The administration of systemic heparin before the clamp is applied to leaking aneurysms does not appear to increase hemorrhage and subsequent mortality and may reduce the need for early thrombectomy.
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- 2008
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20. Electrospray ionization mass spectrometry identifies substrates and products of lipoprotein-associated phospholipase A2 in oxidized human low density lipoprotein.
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Davis B, Koster G, Douet LJ, Scigelova M, Woffendin G, Ward JM, Smith A, Humphries J, Burnand KG, Macphee CH, and Postle AD
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- 1-Alkyl-2-acetylglycerophosphocholine Esterase antagonists & inhibitors, 1-Alkyl-2-acetylglycerophosphocholine Esterase chemistry, Atherosclerosis drug therapy, Biomarkers metabolism, Enzyme Inhibitors therapeutic use, Fatty Acids chemistry, Fatty Acids metabolism, Humans, Inflammation drug therapy, Inflammation enzymology, Lipoproteins, LDL chemistry, Lysophospholipids chemistry, Oxidation-Reduction, Phosphatidylcholines chemistry, 1-Alkyl-2-acetylglycerophosphocholine Esterase metabolism, Atherosclerosis enzymology, Lipoproteins, LDL metabolism, Lysophospholipids metabolism, Phosphatidylcholines metabolism, Spectrometry, Mass, Electrospray Ionization
- Abstract
There is increasing evidence that modified phospholipid products of low density lipoprotein (LDL) oxidation mediate inflammatory processes within vulnerable atherosclerotic lesions. Lipoprotein-associated phospholipase A(2) (Lp-PLA(2)) is present in vulnerable plaque regions where it acts on phospholipid oxidation products to generate the pro-inflammatory lysophsopholipids and oxidized non-esterified fatty acids. This association together with identification of circulating Lp-PLA(2) levels as an independent predictor of cardiovascular disease provides a rationale for development of Lp-PLA(2) inhibitors as therapy for atherosclerosis. Here we report a systematic analysis of the effects of in vitro oxidation in the absence and presence of an Lp-PLA(2) inhibitor on the phosphatidylcholine (PC) composition of human LDL. Mass spectrometry identifies three classes of PC whose concentration is significantly enhanced during LDL oxidation. Of these, a series of molecules, represented by peaks in the m/z range 594-666 and identified as truncated PC oxidation products by accurate mass measurements using an LTQ Orbitrap mass spectrometer, are the predominant substrates for Lp-PLA(2). A second series of oxidation products, represented by peaks in the m/z range 746-830 and identified by LTQ Orbitrap analysis as non-truncated oxidized PCs, are quantitatively more abundant but are less efficient Lp-PLA(2) substrates. The major PC products of Lp-PLA(2), saturated and mono-unsaturated lyso-PC, constitute the third class. Mass spectrometric analysis confirms the presence of many of these PCs within human atherosclerotic lesions, suggesting that they could potentially be used as in vivo markers of atherosclerotic disease progression and response to Lp-PLA(2) inhibitor therapy.
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- 2008
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21. Mobile phones, in combination with a computer locator system, improve the response times of emergency medical services in central London.
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Gossage JA, Frith DP, Carrell TW, Damiani M, Terris J, and Burnand KG
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- Ambulances, Emergency Medical Services, Humans, London, Time Factors, Time and Motion Studies, Cell Phone statistics & numerical data, Emergency Medical Service Communication Systems statistics & numerical data
- Abstract
Introduction: The aim of this study was to determine whether mobile phones and mobile phone locating devices are associated with improved ambulance response times in central London., Patients and Methods: All calls from the London Ambulance Service database since 1999 were analysed. In addition, 100 consecutive patients completed a questionnaire on mobile phone use whilst attending the St Thomas's Hospital Emergency Department in central London., Results: Mobile phone use for emergencies in central London has increased from 4007 (5% of total) calls in January 1999 to 21,585 (29%) in August 2004. Ambulance response times for mobile phone calls were reduced after the introduction of the mobile phone locating system (mean 469 s versus 444 s; P = 0.0195). The proportion of mobile phone calls made from mobile phones for life-threatening emergencies was higher after injury than for medical emergencies (41% versus 16%, P = 0.0063). Of patients transported to the accident and emergency department by ambulance, 44% contacted the ambulance service by mobile phone. Three-quarters of calls made from outside the home or work-place were by mobile phone and 72% of patients indicated that it would have taken longer to contact the emergency services if they had not used a mobile., Conclusions: Since the introduction of the mobile phone locating system, there has been an improvement in ambulance response times. Mobile locating systems in urban areas across the UK may lead to faster response times and, potentially, improved patient outcomes.
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- 2008
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22. Effect of collagen turnover and matrix metalloproteinase activity on healing of venous leg ulcers.
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Meyer FJ, Burnand KG, Abisi S, Tekoppele JM, van Els B, and Smith A
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- Aged, Female, Humans, Male, Peptide Fragments metabolism, Procollagen metabolism, Collagen metabolism, Matrix Metalloproteinases metabolism, Skin metabolism, Varicose Ulcer enzymology, Wound Healing physiology
- Abstract
Background: The presence of fibrous tissue in poorly healing venous leg ulcers suggests abnormal collagen metabolism. The aim was to determine whether there were differences in collagen turnover and matrix metalloproteinase (MMP) activity between ulcers that healed, those that did not heal and normal skin., Methods: Biopsies were taken from the ulcers of 12 patients whose venous ulcers went on to heal and 15 patients whose ulcers failed to heal despite 12 months of compression bandaging. Biopsies were taken from 15 normal controls. Collagen turnover (collagen III N-terminal propeptide (PIIINP) and degraded collagen), and total MMP, MMP-1 and MMP-3 activities were measured., Results: PIIINP and degraded collagen levels were higher in ulcers that healed compared with lesions that failed to heal (P = 0.005 and P < 0.001 respectively) and normal skin (P = 0.003 and P < 0.001). MMP-1 activity was also higher in healing ulcers than resistant ulcers (P < 0.001) and normal skin (P < 0.001). Significantly more total MMP activity was present in all ulcers than in normal skin (P < 0.001), but there was no difference in total MMP (and MMP-3 activity) between ulcers that healed and those that did not., Conclusion: Rapidly healing venous leg ulcers had increased collagen turnover and MMP-1 activity, which appeared to differentiate them from those that failed to heal within 12 months., (2007 British Journal of Surgery Society Ltd. Published by John Wiley & Sons, Ltd.)
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- 2008
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23. Galectin-3 is an amplifier of inflammation in atherosclerotic plaque progression through macrophage activation and monocyte chemoattraction.
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Papaspyridonos M, McNeill E, de Bono JP, Smith A, Burnand KG, Channon KM, and Greaves DR
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- Animals, Biomarkers metabolism, Blotting, Western, Carotid Arteries metabolism, Carotid Arteries pathology, Cells, Cultured, Disease Models, Animal, Disease Progression, Humans, Immunohistochemistry, Macrophage Activation, Macrophages cytology, Mice, Mice, Inbred C57BL, Monocytes cytology, RNA analysis, Random Allocation, Sensitivity and Specificity, Up-Regulation, Carotid Stenosis metabolism, Chemotaxis physiology, Galectin 3 metabolism, Inflammation metabolism, Macrophages metabolism, Monocytes metabolism
- Abstract
Objective: Galectin-3 (Gal-3) is a 26-kDa lectin known to regulate many aspects of inflammatory cell behavior. We assessed the hypothesis that increased levels of Gal-3 contribute to atherosclerotic plaque progression by enhancing monocyte chemoattraction through macrophage activation., Methods and Results: Gal-3 was found to be upregulated in unstable plaque regions of carotid endarterectomy (CEA) specimens compared with stable regions from the same patient (3.2-fold, P<0.05) at the mRNA (n=12) and (2.3-fold, P<0.01) at the protein level (n=9). Analysis of aortic tissue from ApoE-/- mice on a high fat diet (n=14) and wild-type controls (n=9) showed that Gal-3 mRNA and protein levels are elevated by 16.3-fold (P<0.001) and 12.2-fold (P<0.01) and that Gal-3 staining colocalizes with macrophages. In vitro, conditioned media from Gal-3-treated human macrophages induced an up to 6-fold increase in human monocyte chemotaxis (P<0.01, ANOVA), an effect that was reduced by 66 and 60% by Pertussis Toxin (PTX) and the Vaccinia virus protein 35K, respectively. Microarray analysis of human macrophages and subsequent qPCR validation confirmed the upregulation of CC chemokines in response to Gal-3 treatment., Conclusions: Our data suggest that Gal-3 is both a marker of atherosclerotic plaque progression and a central contributor to the pathology by amplification of key proinflammatory molecules.
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- 2008
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24. Effect of statins on proteolytic activity in the wall of abdominal aortic aneurysms.
- Author
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Abisi S, Burnand KG, Humphries J, Waltham M, Taylor P, and Smith A
- Subjects
- Aged, Cathepsins metabolism, Cystatin C, Cystatins metabolism, Female, Humans, Hydroxymethylglutaryl-CoA Reductase Inhibitors therapeutic use, Male, Aorta, Abdominal enzymology, Aortic Aneurysm, Abdominal enzymology, Hydroxymethylglutaryl-CoA Reductase Inhibitors pharmacology, Matrix Metalloproteinase 3 metabolism, Matrix Metalloproteinase 9 metabolism
- Abstract
Background: The aim of this study was to examine the effect of statin treatment on the activity of proteases in the wall of abdominal aortic aneurysms (AAAs)., Methods: The activities of matrix metalloproteinases (MMPs) 9 and 3, cathepsins B, H, K, L and S, and the cystatin C level were measured in extracts of AAA wall taken from 82 patients undergoing AAA repair; 21 patients were receiving statin treatment before surgery. All values were standardized against soluble protein (SP) concentration in the extract, and reported as median (interquartile range) or mean(s.e.m.)., Results: The two groups had similar demographics. Reduced activity of MMP-9 (43 (34-56) versus 80 (62-110) pg per mg SP; P < 0.001), cathepsin H (183 (117-366) versus 321 (172-644) nmol 4-methylcoumarin-7-amide released per mg SP; P = 0.016) and cathepsin L (102 (51-372) versus 287 (112-816) micromol 7-amino-4-trifluoromethylcoumarin released per mg SP; P = 0.020) was found in the statin-treated aortas compared with AAAs from patients not taking a statin. The statin-treated group had lower MMP-3 activity, but this did not reach statistical significance (P = 0.053). Cystatin C levels were higher in statin-treated aortas than in controls (41.3(3.1) versus 28.9(2.1) ng per mg SP; P = 0.003)., Conclusion: Statins decreased the activity of proteases that have been implicated in aneurysm disease., (2007 British Journal of Surgery Society Ltd. Published by John Wiley & Sons, Ltd.)
- Published
- 2008
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25. Imaging of deep vein thrombosis.
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Orbell JH, Smith A, Burnand KG, and Waltham M
- Subjects
- Humans, Magnetic Resonance Angiography methods, Phlebography methods, Recurrence, Tomography, X-Ray Computed methods, Diagnostic Imaging methods, Venous Thrombosis diagnosis
- Abstract
Background: Deep vein thrombosis of the leg affects 1-2 per cent of the population with an annual incidence of 0.5-1 per 1000. It presents with non-specific symptoms and signs making clinical diagnosis difficult. Techniques to image and diagnose this condition are advancing rapidly., Methods and Results: A literature review from 1980 to 2007 was undertaken using PubMed, The Cochrane Library, Medline and Embase. The most frequently used diagnostic test is duplex ultrasonography which is accurate above the knee and has a low cost, but is limited by inaccuracy when assessing the pelvic and distal veins and in diagnosing a new thrombosis in the post-thrombotic limb. Magnetic resonance imaging (MRI) and sonographic elasticity imaging are more recent techniques that have shown promise in overcoming these limitations. However, their availability is currently restricted because they are expensive. Computed tomography (CT) is sensitive, specific and provides good imaging of the pelvis. It has the advantage that it can be performed at the same time as CT pulmonary angiography., Conclusion: MRI has some specific advantages over duplex ultrasonography, but requires refinement before it can be used clinically. Venography or CT venography should be considered when duplex scanning is inadequate., (2008 British Journal of Surgery Society Ltd. Published by John Wiley & Sons, Ltd.)
- Published
- 2008
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26. An increased frequency of the 5A allele in the promoter region of the MMP3 gene is associated with abdominal aortic aneurysms.
- Author
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Deguara J, Burnand KG, Berg J, Green P, Lewis CM, Chinien G, Waltham M, Taylor P, Stern RF, Solomon E, and Smith A
- Subjects
- Aorta diagnostic imaging, Aortic Aneurysm, Abdominal diagnostic imaging, Arterial Occlusive Diseases diagnostic imaging, Arterial Occlusive Diseases genetics, Cohort Studies, Female, Heterozygote, Homozygote, Humans, Male, Ultrasonography, Aortic Aneurysm, Abdominal genetics, Gene Frequency, Genetic Linkage, Matrix Metalloproteinase 3 genetics, Polymorphism, Single Nucleotide, Promoter Regions, Genetic
- Abstract
Matrix metalloproteinase 3 (MMP3), is over expressed in the wall of abdominal aortic aneurysms (AAA), while inactivation of the gene expressing this enzyme is associated with reduced aneurysm formation in an experimental model. The 5A allele of the 5A/6A polymorphism in the promoter region of the MMP3 gene is associated with enhanced MMP3 expression. This study aimed to determine whether the presence of the 5A allele in the MMP3 promoter is a risk factor for AAA, and if this allele is associated with an increased expression of MMP3 in the aneurysm wall. We compared the frequencies of the 5A and 6A alleles in AAA (n = 405), aortic occlusive disease (AOD) (n = 123) and controls (n = 405). The 5A allele frequency was higher in AAA compared with controls (odds ratio - OR 1.32, P = 0.005) and AOD (OR 1.684, P = 0.0004), but was similar in AOD compared to controls (OR 0.78, P = 0.1). The ORs of the 5A/6A and the 5A/5A genotypes were 1.35 and 1.79, compared with 6A homozygotes. Although wall from 5A homozygotes contained 17% more MMP3 mRNA than homozygotes (P = 0.049) the significance of this was lost when adjusted for age and sex (P = 0.069), and size (P = 0.30). Wall from 5A homozygotes did however contain over 45% more MMP3 protein than heterozygotes (P = 0.009 when corrected for age and sex and P = 0.043 when corrected for aneurysm size). It appears that an abnormality in the MMP3 gene is part of the genetic profile that predisposes to aneurysmal disease.
- Published
- 2007
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27. Cysteine protease activity in the wall of abdominal aortic aneurysms.
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Abisi S, Burnand KG, Waltham M, Humphries J, Taylor PR, and Smith A
- Subjects
- Aged, Cathepsins metabolism, Down-Regulation, Female, Humans, Male, Matrix Metalloproteinase 9 metabolism, Middle Aged, Up-Regulation, Aorta enzymology, Aortic Aneurysm, Abdominal enzymology, Aortic Diseases enzymology, Arterial Occlusive Diseases enzymology, Cathepsins analysis, Cystatins analysis, Matrix Metalloproteinase 9 analysis
- Abstract
Background: Cysteine proteases are potent elastolytic enzymes and together with their inhibitor, cystatin C, have been linked with the growth of abdominal aortic aneurysms (AAAs). These enzymes and their inhibitors have previously been studied in AAAs, but comparisons have always been made with wall from normal aorta. Atherosclerosis is a feature of aneurysmal disease and may therefore confound comparisons with normal wall. This study compared the expression and activity of cysteine proteases and their inhibitors in aneurysm wall with their expression in the aortic wall of patients with aortic occlusive disease (AOD)., Methods: Aortic wall was obtained from 82 patients with AAA and 13 with AOD. Protein expression and activity of cathepsin B, H, K, L and S, and cystatins A, B, and C were measured by enzyme-linked immunosorbent assay and specific fluorogenic substrate assays. Matrix metalloproteinase 9 (MMP-9) activity was measured by quantitative bioimmunoassay in the same extracts., Results: AAA wall had 330% more cathepsin H protein (P = .007) and >30% less cystatin C (P = .03) than the aortic wall from patients with AOD. The activity of cathepsins B, H, L, and S was significantly greater in AAA than AOD (376%, [P < .0001], 191%, [P = 0.019], 223%, P = 0.002, and approximately 20% [P = 0.045] respectively). MMP-9 activity was also increased in AAA compared with AOD (P<0.0001) and levels in the wall of AAA correlated positively with cathepsin L activity (r = 0.42, P<.0001) and negatively with cystatin C (r = -0.75, P<.0001)., Conclusions: The activity of four cathepsins B, H, L, and S was higher in the aneurysm wall than in aortic wall of patients with occlusive disease. This was associated with a reduced level of cystatin C in the aneurysmal wall. Cathepsin H was the only protein in which there was a correlation between protein level and activity, which suggests that post-translational modifications were responsible for activation of the other cathepsins. Increased cathepsin activity may influence the activity of MMP-9, which is thought to have an important role in aneurysm development.
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- 2007
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28. Tissue and urinary haemosiderin in chronic leg ulcers.
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Tan J, Smith A, Abisi S, Eastham D, and Burnand KG
- Subjects
- Anemia, Sickle Cell complications, Anemia, Sickle Cell metabolism, Anemia, Sickle Cell urine, Arthritis, Rheumatoid complications, Arthritis, Rheumatoid metabolism, Arthritis, Rheumatoid urine, Biomarkers metabolism, Biomarkers urine, Biopsy, Chronic Disease, Diagnosis, Differential, Hemosiderin urine, Humans, Ischemia complications, Ischemia metabolism, Ischemia urine, Leg Ulcer metabolism, Leg Ulcer pathology, Leg Ulcer urine, Lymphedema complications, Lymphedema metabolism, Lymphedema urine, Predictive Value of Tests, Reproducibility of Results, Skin pathology, Venous Insufficiency complications, Venous Insufficiency metabolism, Venous Insufficiency urine, Anemia, Sickle Cell diagnosis, Arthritis, Rheumatoid diagnosis, Hemosiderin metabolism, Ischemia diagnosis, Leg Ulcer etiology, Lymphedema diagnosis, Skin metabolism, Venous Insufficiency diagnosis
- Abstract
Objective: The aim of this study was to assess the relationship between urinary and tissue haemosiderin in chronic leg ulcers, and its value as a diagnostic test for venous ulceration., Methods: 45 patients with chronic leg ulcers were recruited to the study (24 venous, 6 ischaemic, 6 lymphoedematous, 5 rheumatoid and 4 sickle cell). Punch biopsy of the ulcer edge was taken and early morning urine samples were collected. Positive Prussian-blue urinary haemosiderin granules were measured with a haemocytometer following Perls' staining. The percentage area of histological section staining positively with Perls' was measured using image analysis., Results: 84 urine samples and 46 ulcer biopsies were collected. Urinary haemosiderin was present in 92% of venous ulcer patients, but was absent in the ischaemic ulcer patients (p<0.0001). Significantly more urinary haemosiderin granules were detected in venous ulcer patients compared with patients who had lymphoedema (p<0.05). Tissue haemosiderin was detected in all ulcer types investigated. No correlation was found between the amounts of haemosiderin deposited in the tissue and the amount found in urine (r(2)=0.06)., Conclusions: Haemosiderin is present in the urine of most patients with venous ulcers but not in ischaemia ulcers.
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- 2007
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29. Excision of metatarsal bone and metatarsophalangeal (MTP) joint in neuropathic diabetic foot ulcer.
- Author
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Chan YC, Morales JP, and Burnand KG
- Subjects
- Humans, Diabetic Foot surgery, Metatarsal Bones surgery, Metatarsophalangeal Joint surgery
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- 2007
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30. Excision and meshed skin grafting for leg ulcers resistant to compression therapy.
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Abisi S, Tan J, and Burnand KG
- Subjects
- Adult, Aged, Aged, 80 and over, Chronic Disease, Cohort Studies, Female, Follow-Up Studies, Humans, Leg Ulcer etiology, Length of Stay, Male, Middle Aged, Recurrence, Stockings, Compression, Treatment Outcome, Leg Ulcer surgery, Skin Transplantation methods, Surgical Mesh
- Abstract
Background: The aim of this study was to determine the success of excision and meshed skin grafting for chronic leg ulcers. The effects of different ulcer aetiology and ulcer size on outcome were also assessed., Methods: All patients who had excision and mesh grafting for chronic leg ulceration between January 1996 and December 2004 at St Thomas' Hospital were reviewed. Recurrence was classified as any breakdown of the ulcer during follow-up., Results: Sixty-two patients with 100 chronic leg ulcers underwent operation. Seventy-two of the ulcers were venous and the median ulcer size was 36 (range 1.5-192) cm2. Only three patients left the hospital with their ulcers unhealed, but ulcers had recurred in 28 (28 per cent) by 2 months. A further 17 ulcers recurred later, with just over half (55 per cent) remaining healed by 5 years. There was no difference between the recurrence rates of venous ulcers and ulcers of other aetiologies (P=0.980), or large (more than 10 cm2) and small ulcers (P=0.686)., Conclusion: Wide local excision and meshed skin grafting benefitted over half of these patients with refractory leg ulcers. Recurrence was most likely to occur in the first 2 months and, provided that ulcers were healed at this time, there was a low rate of further breakdown., (Copyright (c) 2006 British Journal of Surgery Society Ltd.)
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- 2007
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31. A painless method of ultrasonically assisted debridement of chronic leg ulcers: a pilot study.
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Tan J, Abisi S, Smith A, and Burnand KG
- Subjects
- Adolescent, Adult, Aged, Aged, 80 and over, Chronic Disease, Female, Humans, Leg Ulcer diagnostic imaging, Male, Middle Aged, Pain Measurement, Pilot Projects, Treatment Outcome, Ultrasonography, Debridement methods, Leg Ulcer surgery, Ultrasonic Therapy
- Abstract
Objectives: Devitalized tissue in a recalcitrant leg ulcer is common and may impede healing. The aim of this study was to evaluate the use of a non-invasive low frequency ultrasound device to debride chronic leg ulcers as an adjunct to compression bandages therapy., Methods: 19 patients with leg ulceration of at least 6 months were recruited. Low frequency ultrasound at 25kHz was delivered by a portable Sonaca--180 via a handheld probe, using normal saline as the irrigation/coupling medium. The ultrasound was applied for 10-20 seconds per probe head area onto the ulcer. Each leg underwent treatment at an interval of 2-3 weeks with compression bandages reapplied at the end of the treatment. Serial colour photographs were taken to evaluate the response at each visit., Results: Each patient received on average 5.7 treatments each ranged from 5-20 minutes depending on the ulcer size. Symptomatic relief (pain and odour reduction) was achieved in 6 patients. 7 patients achieved complete ulcer healing (mean ulcer size=4.72+/-SD 1.872cm(2)) but no response was observed in 8 patients. There were no major complications of the treatment which was relatively painless., Conclusions: The application of low frequency ultrasound debridement may heal some recalcitrant ulcers when standard compression regimens have failed. It is cheap and does not require admission. The role of simple wound cleansing requires further investigation.
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- 2007
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32. Adenoviral urokinase-type plasminogen activator (uPA) gene transfer enhances venous thrombus resolution.
- Author
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Gossage JA, Humphries J, Modarai B, Burnand KG, and Smith A
- Subjects
- Animals, Disease Models, Animal, Enzyme-Linked Immunosorbent Assay, Matrix Metalloproteinase 2 metabolism, Matrix Metalloproteinase 9 metabolism, Mice, Treatment Outcome, Up-Regulation, Urokinase-Type Plasminogen Activator genetics, Urokinase-Type Plasminogen Activator metabolism, Vascular Endothelial Growth Factor A metabolism, Vena Cava, Inferior, Venous Thrombosis metabolism, Venous Thrombosis pathology, Adenoviridae genetics, Gene Transfer Techniques, Urokinase-Type Plasminogen Activator therapeutic use, Venous Thrombosis therapy
- Abstract
Introduction: There is an increase in the natural level of urokinase-type plasminogen activator (uPA) activity within the thrombus during venous thrombus resolution. The use of uPA as a thrombolytic agent in the treatment of acute iliofemoral deep vein thrombosis is not suitable for all patients. This study aimed to determine whether thrombus resolution could be enhanced by upregulating uPA expression using adenoviral gene transfer as an alternative method of delivery., Methods: The production of functional uPA by an adenoviral gene construct (ad.uPA) was confirmed by a colorimetric substrate assay and fibrin plate lysis. Thrombus was formed in the inferior vena cava of wild-type mice and injected, 48-hours after induction, with either a control virus at 10(8) plaque-forming units (pfu) or ad.uPA at 10(7) or 10(8) pfu. Thrombi were removed and weighed 7 days after treatment. Activity of metalloproteinase (MMP) 2 and 9 was measured by zymography and the release of vascular endothelial growth factor (VEGF) and D-dimer levels by enzyme-linked immunoabsorbent assay. The results were expressed as a mean +/- SEM. Values were standardized for wet weight or for soluble protein content (mg/sol protein)., Results: Treatment with ad.uPA reduced thrombus weight by twofold compared with thrombi treated by control virus (15.1 +/- 1.1 mg vs 7.4 +/- 1.3 mg, P = .004). Urokinase activity (17 +/- 3 pg/mg wet weight) was detected in all treated thrombi, but there was no dose-dependent effect. D-dimer activity was increased twofold after treatment with ad.uPA (1.7 +/- 0.15 ng/mg of sol protein vs 0.8 +/- 0.1 ng/mg of sol protein, P = .0015) and was associated with a reduction in thrombus size (P = .03). Urokinase overexpression did not affect the activity of MMP2, MMP9, or VEGF in the thrombus., Conclusion: Increasing urokinase activity within the thrombus significantly enhanced natural thrombus resolution by a fibrinolytic action. Therapeutic delivery of ad.uPA in patients may provide a novel method of treating deep vein thrombosis., Clinical Relevance: The use of urokinase as a thrombolytic agent in the treatment of acute iliofemoral deep vein thrombosis is not suitable for all patients. This study aimed to determine whether thrombus resolution could be enhanced by upregulating urokinase expression using adenoviral gene transfer as an alternative method of therapeutic delivery. The study shows that by increasing urokinase activity within the thrombus, natural thrombus resolution can be significantly enhanced. The delivery of ad.uPA in patients may provide a novel method of treating deep vein thrombosis.
- Published
- 2006
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33. Cerebrospinal fluid drainage in the treatment of spontaneous spinal cord ischemia: a case report.
- Author
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Abisi S, Sayer GL, Tan J, and Burnand KG
- Subjects
- Aged, Angiography, Digital Subtraction, Aorta, Abdominal diagnostic imaging, Humans, Male, Spinal Cord Ischemia cerebrospinal fluid, Spinal Cord Ischemia etiology, Treatment Outcome, Aortic Diseases complications, Arterial Occlusive Diseases complications, Cerebrospinal Fluid, Drainage, Spinal Cord Ischemia therapy
- Abstract
A patient with spontaneous acute spinal cord ischemia successfully treated with cerebrospinal fluid drainage is reported. There are no consensus guidelines on the management of spinal cord ischemia. Various preventive and rehabilitative measures have been suggested, but the best treatment remains unknown.
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- 2006
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34. Development of simultaneous anastomotic false aneurysms at both ends of an autologous vein graft caused by methicillin-resistent Staphylococcus aureus (MRSA).
- Author
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Chan YC, Morales J, and Burnand KG
- Subjects
- Aged, 80 and over, Humans, Male, Postoperative Complications, Transplantation, Autologous, Aneurysm, False etiology, Methicillin Resistance, Popliteal Artery surgery, Saphenous Vein transplantation, Staphylococcal Infections complications, Staphylococcus aureus drug effects, Tibial Arteries surgery
- Abstract
Methicillin-resistant Staphylococcus aureus (MRSA) infection is a well recognised problem, especially in vascular surgical patients with synthetic bypass grafts. This is to our knowledge the first report in the literature of the development of anastomotic false aneurysms at both ends of an autologous vein graft, as a result of MRSA infection within the vascular wall.
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- 2006
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35. Peripheral arterial embolism: prevalence, outcome, and the role of echocardiography in management.
- Author
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Gossage JA, Ali T, Chambers J, and Burnand KG
- Subjects
- Aged, 80 and over, Anticoagulants therapeutic use, Embolectomy, Embolism epidemiology, Embolism etiology, Embolism therapy, Female, Heart Diseases complications, Heart Diseases therapy, Humans, Male, Peripheral Vascular Diseases epidemiology, Peripheral Vascular Diseases etiology, Peripheral Vascular Diseases therapy, Prevalence, Treatment Outcome, Echocardiography, Transesophageal, Embolism diagnostic imaging, Heart Diseases diagnostic imaging, Peripheral Vascular Diseases diagnostic imaging
- Abstract
The aims of this study were to review the prevalence and outcome of all surgically treated upper and lower limb emboli presenting to one vascular unit in the last 3 years and to compare transthoracic with transesophageal echocardiography for defining the source of the embolus. All patients who underwent surgical embolectomy for acute limb ischemia from January 2001 to June 2004 were reviewed. Transthoracic and transesophageal echocardiography were carried out on a subset of consecutive unselected patients. Forty-two patients, with a mean age of 80 years, underwent surgical embolectomy from January 2001 to June 2004 (M/F 1:1.8): 27 for lower limb ischemia and 15 for upper limb ischemia. Two thirds of these patients were found to be in atrial fibrillation at presentation (n = 28), of whom less than a third were receiving anticoagulants or antiplatelet agents (n = 8). The mean hospital stay was 15 days with 36 patients (86%) being fully anticoagulated before discharge from hospital. The 30-day mortality rate was 11% (n = 3/27) with 5 patients requiring fasciotomies (12%) and 3 patients requiring an amputation of the lower limb (11%). Postoperatively, 34 patients (81%) had transthoracic echocardiography (TTE), which demonstrated a source or potential source for thrombus in 19 (56%). Fifteen patients (36%) had transesophageal echocardiography (TEE), which changed the subsequent management in 3 patients. All patients in whom TEE altered clinical management would have required this investigation if standard clinical guidelines were followed. TEE did not identify any additional patients with cardiac embolic sources that were not detected by TTE. Arterial limb emboli are still prevalent, but limb salvage and mortality rates appear to be improving. Despite clear guidelines on anticoagulation for patients in atrial fibrillation, many are not receiving appropriate treatment. Transthoracic echocardiography is a good screening tool for detecting a potential cardiac source for peripheral embolism, with transesophageal echocardiography being reserved for specific indications.
- Published
- 2006
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36. Novel candidate genes in unstable areas of human atherosclerotic plaques.
- Author
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Papaspyridonos M, Smith A, Burnand KG, Taylor P, Padayachee S, Suckling KE, James CH, Greaves DR, and Patel L
- Subjects
- Biomarkers metabolism, Cathepsin B metabolism, Cysteine Endopeptidases genetics, Endothelium, Vascular metabolism, Gene Expression Profiling, Humans, Macrophages metabolism, Macrophages pathology, Matrix Metalloproteinase 9 metabolism, Myocytes, Smooth Muscle metabolism, Myocytes, Smooth Muscle pathology, Oligonucleotide Array Sequence Analysis, RNA, Messenger metabolism, T-Lymphocytes metabolism, Atherosclerosis genetics, Atherosclerosis pathology, Gene Expression
- Abstract
Objective: Comparison of gene expression in stable versus unstable atherosclerotic plaque may be confounded by interpatient variability. The aim of this study was to identify differences in gene expression between stable and unstable segments of plaque obtained from the same patient., Methods and Results: Human carotid endarterectomy specimens were segmented and macroscopically classified using a morphological classification system. Two analytical methods, an intraplaque and an interplaque analysis, revealed 170 and 1916 differentially expressed genes, respectively using Affymetrix gene chip analysis. A total of 115 genes were identified from both analyses. The differential expression of 27 genes was also confirmed using quantitative-polymerase chain reaction on a larger panel of samples. Eighteen of these genes have not been associated previously with plaque instability, including the metalloproteinase, ADAMDEC1 (approximately 37-fold), retinoic acid receptor responder-1 (approximately 5-fold), and cysteine protease legumain (approximately 3-fold). Matrix metalloproteinase-9 (MMP-9), cathepsin B, and a novel gene, legumain, a potential activator of MMPs and cathepsins, were also confirmed at the protein level., Conclusions: The differential expression of 18 genes not previously associated with plaque rupture has been confirmed in stable and unstable regions of the same atherosclerotic plaque. These genes may represent novel targets for the treatment of unstable plaque or useful diagnostic markers of plaque instability.
- Published
- 2006
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37. Management of septic groin complications and infected femoral false aneurysms in intravenous drug abusers.
- Author
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Chan YC and Burnand KG
- Subjects
- Aneurysm, False microbiology, Aneurysm, Infected microbiology, Femoral Artery microbiology, Humans, Inguinal Canal, Treatment Outcome, Aneurysm, False surgery, Aneurysm, Infected surgery, Anti-Bacterial Agents therapeutic use, Femoral Artery surgery, Sepsis drug therapy, Substance Abuse, Intravenous microbiology
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- 2006
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38. Intraluminal thrombus enhances proteolysis in abdominal aortic aneurysms.
- Author
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Carrell TW, Burnand KG, Booth NA, Humphries J, and Smith A
- Subjects
- Aged, Aged, 80 and over, Aortic Aneurysm, Abdominal metabolism, Aortic Aneurysm, Abdominal pathology, Enzyme Activation, Female, Fibrinolysin analysis, Fibrinolysis, Humans, Male, Middle Aged, Plasminogen Activator Inhibitor 1 analysis, Thrombosis enzymology, Thrombosis metabolism, Tissue Plasminogen Activator analysis, Urokinase-Type Plasminogen Activator analysis, alpha-2-Antiplasmin analysis, Aortic Aneurysm, Abdominal complications, Peptide Hydrolases metabolism, Thrombosis complications
- Abstract
This study examined whether intraluminal thrombus in abdominal aortic aneurysms (AAAs) is a source of fibrinolytic activity and proteolysis that could weaken the aneurysm wall. Plasmin, tissue plasminogen activator (tPA), and urokinase plasminogen activator (uPA) activity, plasminogen activator inhibitor 1 (PAI-1), and alpha2-antiplasmin (alpha2AP) antigen were measured in the AAA wall and juxtamural and luminal aspects of intraluminal thrombus in 18 patients. The aneurysm wall contained 100-fold higher tPA activity (1.06 +/- 0.34 [standard error of measurement] U/mg soluble protein) compared with juxtamural thrombus (JMT) (0.011 +/- 0.001 ) and luminal thrombus (LT) (0.01 +/- 0.001) (p < .00001) and over 6-fold higher uPA activity (29.3 +/- 3.4 IU/mg compared with the JMT (4.3 +/- 2.4, p = .00024) and LT (7.9 +/- 1.76, p = .0005). The LT had significantly lower levels of PAI-1 (1.26 +/- 0.34 ng/mg) than the AAA wall (2.08 +/- 0.51, p = .04) and the JMT (3.94 +/- 0.85, p = .007). The levels of alpha2AP in the wall (19.4 +/- 3.1 ng/mg) were lower than in the JMT or LT (43.0 +/- 7.9 ng/mg, p = .013, and 47.6 +/- 6.0 ng/mg, p = .002, respectively). There was no significant difference, however, in plasmin activity among the AAA wall, JMT, and LT. There were significant amounts of latent gelatinase B (matrix metalloproteinase [MMP]-9) in the AAA, JMT, and LT. Mean levels of activated MMP-9 activity were similar in the AAA, JMT, and LT. Plasmin activation of MMPs at the interface between intraluminal thrombus and the aneurysm wall may enhance proteolysis and accelerate aneurysm expansion.
- Published
- 2006
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39. Matrix metalloproteinases in the aneurysm wall of patients treated with low-dose doxycycline.
- Author
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Ding R, McGuinness CL, Burnand KG, Sullivan E, and Smith A
- Subjects
- Administration, Oral, Aged, Aorta, Abdominal enzymology, Double-Blind Method, Enzyme Precursors analysis, Female, Humans, Male, Matrix Metalloproteinase 2 analysis, Matrix Metalloproteinase 3 analysis, Matrix Metalloproteinase 9 analysis, RNA, Messenger analysis, Tissue Inhibitor of Metalloproteinase-2 analysis, Anti-Bacterial Agents pharmacology, Aorta, Abdominal drug effects, Aortic Aneurysm, Abdominal enzymology, Doxycycline pharmacology, Matrix Metalloproteinases analysis
- Abstract
The purpose of this study was to determine the effect of low-dose doxycycline on matrix metalloproteinase (MMP) and tissue inhibitor of metalloproteinase (TIMP)-1 expression in the wall of abdominal aortic aneurysms. A double-blind, randomized study was conducted of patients treated with doxycycline (100 mg/d orally) or placebo for 1 month prior to surgery. MMP-2, -3, and -9 (zymogen and activity); MMP-1, -2, -3, -7, -9, -11, -12, and -14; and TIMP-1 (messenger ribonucleic acid [mRNA]) were measured in the aneurysm wall. No differences were found between the treatment and placebo groups in zymogen levels of MMP-2, -3, or -9 or in the free or total activities of MMP-2 and -9. Treatment with doxycycline also had no effect on the concentration of any mRNA measured. No relationship was found between the number of tablets taken and MMP or TIMP protein, mRNA, or activity levels in the aneurysm wall. Low-dose doxycycline treatment does not alter the expression or activity of metalloproteinases or their inhibitor, TIMP-1, in the aneurysm wall.
- Published
- 2005
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40. The modernisation of the surgical house officer.
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Gossage JA, Modarai B, McGuinness CL, and Burnand KG
- Subjects
- Attitude of Health Personnel, Emergency Service, Hospital, Hospitals, Teaching, Humans, London, Medical Staff, Hospital trends, Night Care, Surveys and Questionnaires, General Surgery education, Medical Staff, Hospital education
- Abstract
Introduction: There have been considerable changes in the junior doctors' hours and working patterns over the last 4 years. The aim of this study was to assess the effect of these changes on the house officers' surgical experience and to obtain their opinions on the 'Hospital at Night' system, which has recently been introduced at our large teaching hospital., Methods: A questionnaire was filled out by surgical house officers at the end of their surgical posts in 2001. The same questionnaire was then repeated for house officers completing the same posts in 2005., Results: Pre-registration house officers now see less acute surgical admissions (mean 5 patients in 3 months in 2005 compared with 35 in 2001; P < 0.0001) and spend less time attending theatre than four years ago (mean 12 sessions in 3 months in 2001 compared with 6 in 2005). Despite the reduction in hours, they are still managing to attend educational sessions. Nine out of ten house officers felt that the 'Hospital at Night' system was unsatisfactory. They were unable to see and clerk acute surgical admissions or go to theatre because they were providing cross cover for other specialties., Conclusions: The full shift system and the introduction of the 'Hospital at Night' team have led to a reduction in acute surgical experience for surgical house officers. The General Medical Council recommendations for reducing non-educational tasks have not been fulfilled despite the evolving role of nurse practitioners.
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- 2005
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41. The role of neovascularisation in the resolution of venous thrombus.
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Modarai B, Burnand KG, Humphries J, Waltham M, and Smith A
- Subjects
- Animals, Anticoagulants pharmacology, Antigens, CD biosynthesis, Antigens, Differentiation, Myelomonocytic biosynthesis, Blood Coagulation, Bone Marrow Cells cytology, Cytokines metabolism, Genetic Therapy methods, Humans, Inflammation, Models, Anatomic, Models, Biological, Stem Cells cytology, Veins pathology, Neovascularization, Physiologic, Thrombosis therapy, Venous Thrombosis therapy
- Abstract
Deep vein thrombosis (DVT) can give rise to chronic debilitating complications, which are expensive to treat. Anticoagulation, the standard therapy for DVT, prevents propagation, but does not remove the existing thrombus, which undergoes slow natural resolution. Alternative forms of treatment that accelerate resolution may arise from a better understanding of the cellular and molecular pathways that regulate the natural resolution of thrombi. This review will outline our current understanding of the mechanisms of thrombus resolution and the role of neovascularisation in this process. Novel experimental treatments that may one day find clinical use are also discussed. The process of thrombus resolution resembles wound healing. The mainly monocytic inflammatory infiltrate, which develops, is associated with the appearance of vascular channels. These cells may drive resolution by encouraging angiogenesis, which contributes to restoration of the vein lumen. Significant numbers of bone marrow-derived progenitor cells have also been found in naturally resolving thrombi, but their precise phenotype and their role in thrombus recanalisation is unclear. Enhanced thrombus neovascularisation and rapid vein recanalisation have been achieved in experimental models with proangiogenic agents. Recent reports of the role of bone marrow-derived progenitor cells in the revascularisation of ischaemic tissues suggest that it may be possible to obtain the same effect by delivering pluripotent or lineage specific stem cells into thrombus. These cells could contribute to thrombus recanalisation by expressing a variety of proangiogenic cytokines or by lining the new vessels that appear within the thrombus.
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- 2005
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42. Sequential cohort study of Dacron patch closure following carotid endarterectomy.
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Ali T, Sabharwal T, Dourado RA, Padayachee TS, Hunt T, and Burnand KG
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- Adult, Aged, Aged, 80 and over, Cohort Studies, Female, Humans, Male, Middle Aged, Secondary Prevention, Surgical Mesh, Treatment Outcome, Carotid Stenosis surgery, Endarterectomy, Carotid methods, Ischemic Attack, Transient prevention & control, Polyethylene Terephthalates therapeutic use, Stroke prevention & control
- Abstract
Background: Carotid endarterectomy reduces the risk of stroke and death in patients with severe carotid artery stenosis. This study examined whether the technique used to close the arteriotomy influenced the rate of perioperative transient ischaemic attack (TIA), stroke or death., Methods: A cohort of 236 patients undergoing carotid endarterectomy at a single centre was studied; 117 patients had primary closure of the arteriotomy and 119 patients in a sequential series had closure with a Dacron patch. A standard endarterectomy with completion intraoperative duplex imaging and digital subtraction angiography was used throughout., Results: Patch closure was associated with a significant reduction in the 30-day combined death, stroke and TIA rate: 10.3 per cent for primary closure versus 2.5 per cent for patch closure (P = 0.017). The risk of any cerebral event (stroke or TIA) was also significantly reduced (7.7 versus 1.7 per cent; P = 0.033). Residual stenosis on completion angiography was more common after primary closure (24.6 versus 7.4 per cent; P = 0.003)., Conclusion: Dacron patch closure had a higher technical success rate on completion imaging and was associated with a significant reduction in the risk of perioperative stroke, TIA and death., (Copyright (c) 2005 British Journal of Surgery Society Ltd.)
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- 2005
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43. Upper limb ischemia: 20 years experience from a single center.
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Deguara J, Ali T, Modarai B, and Burnand KG
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- Adult, Aged, Arteriosclerosis complications, Arteriosclerosis surgery, Embolectomy, Female, Humans, Ischemia etiology, Male, Middle Aged, Prospective Studies, Thoracic Outlet Syndrome surgery, Thrombectomy, Treatment Outcome, Arm blood supply, Arm Injuries surgery, Ischemia surgery
- Abstract
The objective of this study was to review a single center's experience of upper limb revascularization over 20 years. All patients undergoing operative or endovascular upper limb revascularization between June 1983 and July 2003 were identified. One hundred eighty-four upper limb revascularization procedures were carried out on 172 patients. Sixty-one patients had a thromboembolic event (35%), 53 patients presented with a traumatic vascular injury (31%), and 29 patients had symptoms of chronic atherosclerotic upper limb ischemia (17%). Fifteen patients had subclavian steal syndrome, eight patients had thoracic outlet compression, and six patients had iatrogenic injuries of the upper limb arteries. Fifty-five thromboembolectomies were performed, 37 under locoregional anesthesia. Ten patients (18.2%) died from cardiopulmonary causes following embolectomy. Fifteen reversed saphenous vein bypass grafts were performed for traumatic damage. Twenty-seven patients had a primary repair, and five required a vein patch. One patient subsequently had an arm amputation, and two patients died. Twelve patients presenting with chronic arm ischemia had a subclavian angioplasty, 12 patients had a proximal bypass, and in 5 patients, stenoses were stented. The mortality in this group was 6.9% (2 of 29). The mortality for upper limb revascularization was 8.7%. Almost all deaths occurred after upper limb embolectomy, and the mortality of this procedure was similar to that of lower limb embolectomy. Deaths were the result of cardiac comorbidity, and this should be actively sought and treated if outcomes are to improve.
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- 2005
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44. Comparison of extra-anatomic bypass grafting with angioplasty for atherosclerotic disease of the supra-aortic trunks.
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Modarai B, Ali T, Dourado R, Reidy JF, Taylor PR, and Burnand KG
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- Adult, Aged, Aged, 80 and over, Angioplasty methods, Female, Follow-Up Studies, Humans, Male, Middle Aged, Prospective Studies, Stents, Aortic Diseases surgery, Arm blood supply, Arteriosclerosis surgery, Blood Vessel Prosthesis Implantation methods, Ischemia etiology, Subclavian Steal Syndrome surgery
- Abstract
Background: Symptomatic stenosis of the supra-aortic trunks (subclavian, innominate and common carotid arteries) can be treated by angioplasty/stenting or surgical bypass. The aim of this study was to compare the initial success and outcome of these two types of treatment., Methods: A prospective database was used to collect information on the presentation, initial success, complications and outcome in 76 patients treated in a single centre between 1983 and 2003., Results: Thirty-five surgical extra-anatomic bypasses were performed, 13 carotid to carotid, 14 carotid to subclavian, two carotid to axillary, three axillary to axillary, one subclavian to axillary and two subclavian to subclavian. One graft occluded after 19 years. No limbs were amputated and no patient had a stroke. The secondary patency rate was 97 per cent at a mean follow-up of 5 years. Forty-one angioplasties were attempted, 34 of the left subclavian, six of the right subclavian and one of the innominate artery. Angioplasty for six subclavian occlusions was unsuccessful. Twenty-seven of 33 arteries remained patent at a mean follow-up of 4 years after a successful endovascular procedure., Conclusion: Extra-anatomic bypass for supra-aortic trunk disease has a better patency than angioplasty, with a comparable complication rate., (Copyright (c) 2004 British Journal of Surgery Society Ltd)
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- 2004
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45. Minimum internal diameter of the greater saphenous vein is an important determinant of successful femorodistal bypass grafting that is independent of the quality of the runoff.
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Ishii Y, Gossage JA, Dourado R, Sabharwal T, and Burnand KG
- Subjects
- Adult, Aged, Aged, 80 and over, Anastomosis, Surgical methods, Female, Humans, Ischemia physiopathology, Leg blood supply, Limb Salvage methods, Male, Middle Aged, Peripheral Vascular Diseases physiopathology, Peripheral Vascular Diseases surgery, Popliteal Artery surgery, Radiography, Saphenous Vein diagnostic imaging, Saphenous Vein surgery, Treatment Outcome, Vascular Surgical Procedures methods, Femoral Artery surgery, Ischemia surgery, Saphenous Vein anatomy & histology, Vascular Patency physiology
- Abstract
The greater saphenous vein is assessed as part of the workup for femorodistal bypass surgery in our unit. The aim of this study was to determine whether the minimum internal diameter (MID) of the vein predicted graft patency and limb salvage in femorodistal bypass surgery, independently of the quality of the runoff. A consecutive series of 67 infrainguinal vein bypass grafts were performed on 62 patients with critical lower limb ischemia. All were followed for at least 1 year. The MID of the greater saphenous vein was calculated from preoperative saphenograms, and all of the arteriograms were scored for their runoff using an ad hoc method approved by the Society for Vascular Surgery. The cumulative patency of all vein grafts at 3 years was 59 +/- 7% (SE), and the limb salvage was 85 +/- 5%. All femoropopliteal bypass grafts were patent at 3 years if the MID of the vein was greater than 3.0 mm. The crural bypass patency was 66 +/- 12% for an MID greater than 3.0 mm and only 27 +/- 12% for an MID less than 3.0 mm. Every extra point on the runoff score increased the hazard of bypass failure by 16% (95% CI 1.0-34; p < .05). Vein diameter and runoff score were independent of one another (r2 = -.106). The MID of the greater saphenous vein is a major determinant of outcome in infrainguinal vein bypass surgery independent of the arterial runoff.
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- 2004
- Full Text
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46. Complications of reperfusion in acute aortic artery occlusion following saddle embolization originating from an atrial myxoma.
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Ali T, Castro J, Young CR, and Burnand KG
- Subjects
- Acute Disease, Acute Kidney Injury etiology, Aortic Diseases etiology, Arterial Occlusive Diseases etiology, Heart Atria, Humans, Male, Middle Aged, Reperfusion Injury etiology, Thromboembolism complications, Treatment Outcome, Aortic Diseases surgery, Arterial Occlusive Diseases surgery, Heart Neoplasms complications, Myxoma complications, Reperfusion adverse effects
- Abstract
A 58-year-old man presented to the hospital with an 8-hour history of acute-onset bilateral lower limb ischemia. A large saddle embolus had occluded the aorta and could not be removed by balloon endarterectomy through the femoral arteries. Successful open aortic and femoral thromboembolectomy followed by extensive fasciotomies was accompanied by severe reperfusion injury. Life-threatening hyperkalemia was associated with three episodes of intraoperative ventricular fibrillation and ventricular tachycardia requiring cardiac massage and defibrillation. A dextrose-insulin-bicarbonate infusion was required to correct the hyperkalemia. Rhabdomyolysis developed at 24 hours, causing marked myoglobinuria and acute renal failure, which required hemofiltration. Histology of the recovered embolus confirmed an atrial myxoma, and when the patient had fully recovered, open cardiac surgery was carried out to resect the tiny stump of residual myxoma. Rhabdomyolysis associated with a myxomatous saddle embolus has not been previously reported. This case highlights the need for pre- and perioperative measures to be taken to overcome hyperkalemia and acute renal failure when revascularizing acute, massive, prolonged ischemia of the lower body.
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- 2004
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47. The effect of anticoagulation with subcutaneously delivered polyethylene glycol conjugated hirudin and recombinant tissue plasminogen activator on recurrent stenosis in the rabbit double-balloon injury model.
- Author
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Alexander B, Burnand KG, Lattimer CL, Humphries J, Gaffney PJ, Eastham D, and Smith A
- Subjects
- Animals, Anticoagulants therapeutic use, Carotid Arteries drug effects, Carotid Arteries pathology, Carotid Artery Diseases drug therapy, Carotid Artery Diseases pathology, Constriction, Pathologic etiology, Disease Models, Animal, Hirudins blood, Hirudins pharmacology, Rabbits, Recombinant Proteins, Recurrence, Tissue Plasminogen Activator pharmacology, Catheterization adverse effects, Constriction, Pathologic drug therapy, Hirudins administration & dosage, Hirudins analogs & derivatives, Tissue Plasminogen Activator administration & dosage
- Abstract
Myointimal hyperplasia is the condition usually responsible for recurrent stenosis (restenosis) after endarterectomy, bypass grafting and angioplasty. Its cause is still not known. The present study examined whether inhibition of thrombin by tissue plasminogen activator (r-TPA) or polyethylene glycol recombinant hirudin (PEG-hirudin) could reduce restenosis in an animal model. Restenosis was induced in 20 cholesterol-fed rabbits. The right carotid artery underwent a double-balloon injury while left carotid artery acted as a control. Recombinant tissue plasminogen activator (1 mg kg(-1) s.c.) and PEG-hirudin (0.7 mg kg(-1) s.c.) were given subcutaneously with normal saline acting as a control. Blood levels of PEG-hirudin were measured by both ELISA and an Ecarin (activity) assay. Vessel dimensions were measured in histological sections, obtained from perfusion-fixed tissue, using computerised planimetry. The model reproduced many of the histological changes found in human restenosis, such as intramural thrombus, rupture of the elastic lamina, macrophage infiltration and smooth muscle migration. Reinjury caused an almost three-fold reduction in the area of the lumen (median 0.25 mm(2)) compared with uninjured vessels (median 0.72 mm(2)). The mean plasma levels of PEG-hirudin and r-tPA achieved were 291 ng/ml (S.E.M. 28 ng/ml) and 34 IU/ml (S.E.M. 12 IU/ml), respectively. PEG-hirudin significantly inhibited the effect of balloon injury on luminal area compared with saline-treated controls (0.21 versus 0.44 mm(2), respectively, P<0.05). Recombinant tPA also had a similar inhibitory affect, but this did not reach statistical significance (0.16 versus 0.44 mm(2), respectively, P>0.05). The magnitude of luminal narrowing was significantly reduced by subcutaneous injection of PEG-hirudin. Further studies are required to determine whether this effect can be enhanced by other antithrombins or improved methods of delivery.
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- 2004
- Full Text
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48. Increased but ineffectual angiogenic drive in nonhealing venous leg ulcers.
- Author
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Drinkwater SL, Burnand KG, Ding R, and Smith A
- Subjects
- Angiogenesis Inducing Agents analysis, Angiogenesis Inducing Agents immunology, Angiopoietins analysis, Angiopoietins immunology, Humans, RNA, Messenger, Varicose Ulcer physiopathology, Vascular Endothelial Growth Factors analysis, Wound Healing physiology, Neovascularization, Physiologic physiology, Varicose Ulcer immunology, Vascular Endothelial Growth Factors immunology, Wound Healing immunology
- Abstract
Objective: Our previous work demonstrated that angiogenesis is inhibited in nonhealing venous ulcers. The object of this study was to determine whether local expression of vascular endothelial growth factor (VEGF) and other major regulators of vessel growth are related to healing of venous ulcers., Subjects and Methods: The study included 35 patients with venous ulcers (CEAP 6) and 9 patients whose ulcers had healed (CEAP 5). Control subjects were 18 patients undergoing routine operations (8 with closed suction drains, 10 standard skin biopsies). Healing ulcers were defined as having healed in less than a year from entry to the study; nonhealing ulcers failed to heal in this period. A 1-cm square biopsy specimen was taken from the edge of the ulcer or from a site of lipodermatosclerosis around a healed ulcer. Wound fluids were aspirated from beneath transparent occlusive dressings. Concentrations of VEGF(165) and VEGF-R1 were measured in tissue homogenates with enzyme-linked immunosorbent assay, and results are expressed as mean +/- SEM per milligram of soluble protein (SP). Expression of mRNA transcripts for the VEGF splice variants VEGF(121), VEGF(189), and VEGF(165); the receptors VEGF-R1 and VEGF-R2; the angiopoietins Ang-1 and Ang-2; and their receptor, Tie-2, were measured in biopsy samples with multiplex polymerase chain reaction. Expression of each transcript was normalized to that of the housekeeping gene, GAPDH. Results were analyzed with analysis of variance, t test, and chi(2) test., Results: There was no difference in VEGF(165) protein concentration between biopsy specimens from healing ulcers (2.12 +/- 0.34 ng/mg SP; n = 18) and nonhealing ulcers (2.36 +/- 0.39 ng/mg SP; n = 12), but concentration was higher in all ulcer samples compared with healthy skin (0.57 +/- 0.20 ng/mg SP; n = 10; P <.01)) and healed ulcers (0.33 +/- 0.06 ng/mg SP; n = 9; P <.01). Concentration of VEGF(165) protein in wound fluid was significantly higher in nonhealing venous ulcers (67.17 +/- 13.87 ng/mg SP; n = 13) compared with healing venous ulcers (32.19 +/- 7.90 ng/mg SP; n = 19; P <.05) or acute wounds (12.26 +/- 4.50; n = 8; P <.01). Concentration of VEGF-R1 was similar in wound fluid obtained from healing ulcers (7.18 +/- 1.34 ng/mg SP; n = 13) and nonhealing ulcers (7.02 +/- 1.21 ng/mg SP; n = 19), and acute wounds (7.12 +/- 2.35 ng/mg SP; n = 8). There was a weak but significant correlation between VEGF(165) protein concentration in the ulcer biopsy specimen and wound fluid from the same ulcer (R(2) = 0.2; P =.019; n = 27). Expression of mRNA for VEGF receptors and Tie-2 was poor. VEGF(121) was expressed in all samples, and VEGF(165) in 43 of 48 samples. mRNA expression of VEGF(189) (P =.001), Ang-1 (P =.002), and Ang-2 (P =.026) was found in more samples from unhealed ulcers than from other sites. Healed ulcers had reduced mRNA expression of VEGF(165) (0.181 +/- 0.003) than did healing ulcers (0.307 +/- 0.016; P =.007) or nonhealing ulcers (0.375 +/- 0.033; P =.001). Relative expression of VEGF(165) to Ang-2 was much lower in healed ulcers (0.4236 +/- 0.060) than in healing ulcers (1.382 +/- 0.235; P =.010) and nonhealing ulcers (1.887 +/- 0.280; P =.003)., Conclusion: In nonhealing venous ulcers there is a consistently high level of expression of VEGF, at both the gene transcript and protein level. As our previous data demonstrated that angiogenesis is depressed in these poorly healing ulcers, an increase in VEGF production may indicate an increased but ineffectual angiogenic drive. It is also possible that undiscovered inhibitors are released in the ulcer environment.
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- 2003
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49. Randomized clinical trial of three-layer paste and four-layer bandages for venous leg ulcers.
- Author
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Meyer FJ, McGuinness CL, Lagattolla NR, Eastham D, and Burnand KG
- Subjects
- Aged, Cohort Studies, Female, Humans, Male, Middle Aged, Ointments, Prospective Studies, Treatment Outcome, Treatment Refusal, Wound Healing, Bandages, Leg Ulcer therapy
- Abstract
Background: Both four-layer and three-layer paste bandages are widely used in the treatment of venous leg ulcers. The aim of this study was to compare the efficacy of these two bandaging regimens., Methods: The study was a prospective, randomized, open comparison of a consecutive cohort of 133 patients with venous ulcers. Participants were stratified by ulcer size into one of three groups and were randomized within each group to receive either three-layer paste or four-layer bandages. All patients were followed for 1 year. The time taken to complete ulcer healing was the primary endpoint. The time taken to apply the bandages, comfort, tolerability and cost were also assessed. Analysis was performed on the basis of intention to treat., Results: Ulcers healed completely in 51 (80 per cent) of 64 patients treated with three-layer paste bandages compared with 45 (65 per cent) of 69 patients treated with the four-layer regimen (P = 0.031). This difference developed only after 20 weeks of treatment. The median times to complete healing were 12 weeks for three-layer and 16 weeks for four-layer treatment (P = 0.040). Results of venous function tests, including half-refilling times, were similar in the two groups., Conclusion: Three-layer paste bandages were significantly more effective at healing venous ulcers than the four-layer regimen in this study., (Copyright 2003 British Journal of Surgery Society Ltd. Published by John Wiley & Sons, Ltd.)
- Published
- 2003
- Full Text
- View/download PDF
50. The BEST study--a prospective study to compare business class versus economy class air travel as a cause of thrombosis.
- Author
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Jacobson BF, Münster M, Smith A, Burnand KG, Carter A, Abdool-Carrim AT, Marcos E, Becker PJ, Rogers T, le Roux D, Calvert-Evers JL, Nel MJ, Brackin R, and Veller M
- Subjects
- Adult, Case-Control Studies, Female, Fibrin Fibrinogen Degradation Products analysis, Humans, Incidence, Leg blood supply, Male, Middle Aged, Phlebotomy, Prospective Studies, Regression Analysis, Specimen Handling, Ultrasonography, Venous Thrombosis diagnosis, Venous Thrombosis diagnostic imaging, Aircraft, Travel, Venous Thrombosis etiology
- Abstract
Background: As many as 10% of airline passengers travelling without prophylaxis for long distances may develop a venous thrombosis. There is, however, no evidence that economy class travellers are at increased risk of thrombosis., Objectives: A suitably powered prospective study, based on the incidence of deep-vein thrombosis (DVT) reported in previous studies on long-haul flights, was designed to determine the incidence of positive venous duplex scans and D-dimer elevations in low and intermediate-risk passengers, comparing passengers travelling in business and economy class., Patients/methods: Eight hundred and ninety-nine passengers were recruited (180 travelling business class and 719 travelling economy). D-dimers were measured before and after the flight. A value greater than 500 ng/ml was accepted as abnormal. A thrombophilia screen was conducted which included the factor V Leiden mutation, the prothombin 20210A mutation, protein C and S levels, antithrombin levels, and anticardiolipin antibodies immunoglobulin G (IgG) and immunoglobulin M (IgM). On arrival, lower limb compression ultrasonography of the deep veins was performed. Logistical regression analysis was used to determine the risk factors related to abnormally high D-dimer levels., Results: Only 434 subjects had a full venous duplex scan performed. None had ultrasonic evidence of venous thrombosis. Nine passengers tested at departure had elevated D-dimer levels and these volunteers were excluded from further study. Seventy-four of the 899 passengers had raised D-dimers on arrival. Twenty-two of 180 business class passengers (12%) developed elevated D-dimers compared with 52 of 719 economy class passengers (7%). There was no significant association between elevation of D-dimers and the class flown (odds ratio (OR) 0.61, p = 0.109). The factor V Leiden mutation, factor VIII levels and the use of aspirin were, however, associated with raised D-dimers (OR 3.36, p = 0.024; OR 1.01, p = 0.014; and OR 2.04, p = 0.038, respectively). Five hundred and five passengers were contacted within 6 months and none reported any symptoms of a clinical thrombosis or pulmonary embolus., Conclusion: The incidence of ultrasonically proven DVT is much lower than previously reported. However, more than 10% of all passengers developed raised D-dimers, which were unrelated to the class flown. A rise in D-dimers is associated with an inherent risk of thrombosis and/or thrombophilia, demonstrates activation of both the coagulation and fibrinolytic systems during long-haul flights, and may indicate the development of small thrombi.
- Published
- 2003
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