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1.
Clin Radiol ; 72(4): 338.e11-338.e17, 2017 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-28041651

RESUMO

AIM: To review the radiology-led ultrasound (US) surveillance programme for the detection of hepatocellular carcinoma (HCC) in cirrhotic patients in a UK tertiary-referral centre. MATERIALS AND METHODS: The radiology information system was searched for patients who had undergone US for surveillance of cirrhosis from September 2009 to May 2013. Patient demographics and cirrhosis aetiology were documented. Data including numbers of surveillance scans, abnormal findings suspicious for HCC, subsequent radiological investigations, numbers of HCC and survival for HCC patients were recorded. Service performance data, such as rates of attendance and rebooking, were also recorded. RESULTS: Eight hundred and four patients entered surveillance and 2,366 surveillance US examinations were performed; 368 (46%) underwent follow-up (6-monthly US). Abnormalities leading to further radiological investigations were found in 81 patients. Reasons for incomplete surveillance included non-attendance and radiology failure to re-book appointments. HCC was diagnosed in 22 patients. Fourteen had HCC diagnosed on a surveillance scan, eight had HCC diagnosed on a scan performed for other reasons. Patients diagnosed with HCC on a surveillance scan were more likely to be treated with curative intent and had longer survival. CONCLUSION: Even with a radiology-led recall service for HCC surveillance, the proportion of patients receiving scans 6-monthly was low, due in part to the lack of organisational support that is available for other screening programmes. This study gives a realistic representation of the implementation of surveillance in a UK hospital at the current time and of the rates of HCC proceeding to treatment.


Assuntos
Carcinoma Hepatocelular/diagnóstico por imagem , Carcinoma Hepatocelular/epidemiologia , Neoplasias Hepáticas/diagnóstico por imagem , Neoplasias Hepáticas/epidemiologia , Sistemas de Informação em Radiologia , Ultrassonografia , Feminino , Humanos , Fígado/diagnóstico por imagem , Cirrose Hepática/diagnóstico por imagem , Cirrose Hepática/epidemiologia , Neoplasias Hepáticas/complicações , Masculino , Pessoa de Meia-Idade , Vigilância da População , Encaminhamento e Consulta/estatística & dados numéricos , Estudos Retrospectivos , Centros de Atenção Terciária , Reino Unido/epidemiologia
2.
Atherosclerosis ; 220(2): 593-7, 2012 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-22196149

RESUMO

The British Heart Foundation sponsors the Michael Davies Young Investigator Award, and at its presentation in the Spring of 2009 two collaborators of Michael Davies spoke regarding their experiences on the Plaque Vulnerability project with him. This was to provide the winner and other nominees for the award, and colleagues at the meeting, descriptions of collaborating with Michael to sustain more than his name in association with the award. This article is an expansion of the personal reminiscences given at the time as a tribute to him, and to provide an inside story of how collaboration with such a prominent cardiac pathologist worked.


Assuntos
Pesquisa Biomédica/história , Cardiologia/história , Comportamento Cooperativo , Placa Aterosclerótica/história , Distinções e Prêmios , Bibliometria , Progressão da Doença , História do Século XX , Humanos , Placa Aterosclerótica/patologia
3.
J R Soc Interface ; 7(47): 967-88, 2010 Jun 06.
Artigo em Inglês | MEDLINE | ID: mdl-20022896

RESUMO

We investigate the flow dynamics and oscillatory behaviour of wall shear stress (WSS) vectors in intracranial aneurysms using high resolution numerical simulations. We analyse three representative patient-specific internal carotid arteries laden with aneurysms of different characteristics: (i) a wide-necked saccular aneurysm, (ii) a narrower-necked saccular aneurysm, and (iii) a case with two adjacent saccular aneurysms. Our simulations show that the pulsatile flow in aneurysms can be subject to a hydrodynamic instability during the decelerating systolic phase resulting in a high-frequency oscillation in the range of 20-50 Hz, even when the blood flow rate in the parent vessel is as low as 150 and 250 ml min(-1) for cases (iii) and (i), respectively. The flow returns to its original laminar pulsatile state near the end of diastole. When the aneurysmal flow becomes unstable, both the magnitude and the directions of WSS vectors fluctuate at the aforementioned high frequencies. In particular, the WSS vectors around the flow impingement region exhibit significant spatio-temporal changes in direction as well as in magnitude.


Assuntos
Artéria Carótida Interna/fisiopatologia , Aneurisma Intracraniano/fisiopatologia , Artéria Carótida Interna/diagnóstico por imagem , Ventilação de Alta Frequência , Humanos , Aneurisma Intracraniano/diagnóstico por imagem , Fenômenos Físicos , Fluxo Pulsátil , Radiografia , Estresse Mecânico , Sístole
4.
J Biomech ; 38(6): 1283-90, 2005 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-15863113

RESUMO

A three-dimensional model with simplified geometry for the branched coronary artery is presented. The bifurcation is defined by an analytical intersection of two cylindrical tubes lying on a sphere that represents an idealized heart surface. The model takes into account the repetitive variation of curvature and motion to which the vessel is subject during each cardiac cycle, and also includes the phase difference between arterial motion and blood flowrate, which may be nonzero for patients with pathologies such as aortic regurgitation. An arbitrary Lagrangian Eulerian (ALE) formulation of the unsteady, incompressible, three-dimensional Navier-Stokes equations is employed to solve for the flow field, and numerical simulations are performed using the spectral/hp element method. The results indicate that the combined effect of pulsatile inflow and dynamic geometry depends strongly on the aforementioned phase difference. Specifically, the main findings of this work show that the time-variation of flowrate ratio between the two branches is minimal (less than 5%) for the simulation with phase difference angle equal to 90 degrees, and maximal (51%) for 270 degrees. In two flow pulsatile simulation cases for fixed geometry and dynamic geometry with phase angle 270 degrees, there is a local minimum of the normalized wall shear rate amplitude in the vicinity of the bifurcation, while in other simulations a local maximum is observed.


Assuntos
Velocidade do Fluxo Sanguíneo/fisiologia , Pressão Sanguínea/fisiologia , Vasos Coronários/anatomia & histologia , Vasos Coronários/fisiologia , Modelos Cardiovasculares , Fluxo Pulsátil/fisiologia , Animais , Simulação por Computador , Humanos , Resistência ao Cisalhamento
5.
Curr Opin Mol Ther ; 3(4): 327-37, 2001 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-11525556

RESUMO

We are now approaching the reality of success in gene therapy as our knowledge of the genetic basis of disease continues to grow, coupled with improved delivery methods for therapeutic nucleic acid molecules. It is apparent that gene therapy can be divided into two specific and very different approaches in which gene replacement, or augmentation, is differentiated from gene repair. In fact, gene augmentation is characterized by the delivery of the coding sequence of the gene of interest in an expression cassette. In contrast, gene repair differs in that the process targets for correction of the mutation responsible for the genetic disorder. The in situ repair of a gene has many advantages over conventional replacement methods. This review will concentrate on the various strategies currently available for gene repair. The potential benefits of correction versus augmentation will be addressed and possible future developments outlined.


Assuntos
Marcação de Genes , Terapia Genética , Células Cultivadas , Humanos , Oligonucleotídeos/uso terapêutico , Recombinação Genética
6.
Am J Gastroenterol ; 96(7): 2255-6, 2001 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-11467663

RESUMO

Cyclosporine is a potent suppresser of cell-mediated immunity that is mainly used in organ transplantation to prevent rejection. It is also being used increasingly outside of transplantation and probably is the only new treatment to have made an impact in acute ulcerative colitis (UC) resistant to steroid therapy. We describe a case of Nocardia asteroides lung abscess in a patient treated with cyclosporine for acute steroid resistant UC that was successfully managed with antibiotics and by discontinuing cyclosporine. With increasing use of cyclosporine for acute UC it is to be anticipated that opportunistic infections such as Nocardia will be more frequently encountered in the future.


Assuntos
Colite Ulcerativa/complicações , Ciclosporina/uso terapêutico , Imunossupressores/uso terapêutico , Abscesso Pulmonar/diagnóstico , Nocardiose/diagnóstico , Nocardia asteroides , Infecções Oportunistas/diagnóstico , Doença Aguda , Idoso , Colite Ulcerativa/tratamento farmacológico , Humanos , Abscesso Pulmonar/complicações , Abscesso Pulmonar/diagnóstico por imagem , Masculino , Nocardiose/complicações , Nocardiose/diagnóstico por imagem , Infecções Oportunistas/complicações , Infecções Oportunistas/diagnóstico por imagem , Radiografia
7.
JAMA ; 285(19): 2449-50, 2001 May 16.
Artigo em Inglês | MEDLINE | ID: mdl-11368694
8.
J Hepatol ; 33(3): 371-5, 2000 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-11019991

RESUMO

BACKGROUND/AIM: Azathioprine is standard therapy for maintenance of remission in patients with autoimmune hepatitis. However, approximately 15% of patients are intolerant of therapy and 10% do not respond to it. There is a need for alternative therapies. We describe here the results of mycophenolate mofetil therapy in patients with autoimmune hepatitis. PATIENTS: We studied seven patients with type 1 AIH (six female). Three were intolerant of azathioprine and had elevated transaminases and liver histology showing active disease despite prednisolone therapy. Four had been on a dose of 2 mg per kg of azathioprine without complete normalisation of ALT, and had liver biopsies showing active disease. All were treated with mycophenolate 1 g bd and were followed for a median of 46 months (21-59). End points were improvement in histological inflammation, ALT and prednisolone dose. RESULTS: Five of the seven (71%) patients had normal transaminases after 3 months of treatment. The steroid dose fell from a median of 20 mg per day to 2 mg per day at 9 months (p=0.0001) and the hepatic activity index fell from median 11 to 3 (p=0.001) after 7 months of therapy. One patient required dose reduction because of a fall in white cell count. No other adverse effects were seen. CONCLUSIONS: Mycophenolate mofetil is effective and well tolerated in patients with type 1 AIH who are intolerant of, or do not respond to, azathioprine.


Assuntos
Azatioprina/efeitos adversos , Azatioprina/uso terapêutico , Hepatite Autoimune/tratamento farmacológico , Imunossupressores/uso terapêutico , Ácido Micofenólico/análogos & derivados , Ácido Micofenólico/uso terapêutico , Adolescente , Adulto , Alanina Transaminase/sangue , Anti-Inflamatórios/administração & dosagem , Anti-Inflamatórios/uso terapêutico , Relação Dose-Resposta a Droga , Resistência a Medicamentos , Hepatite Autoimune/patologia , Humanos , Imunossupressores/efeitos adversos , Contagem de Leucócitos , Fígado/patologia , Ácido Micofenólico/efeitos adversos , Prednisona/administração & dosagem , Prednisona/uso terapêutico
9.
Aliment Pharmacol Ther ; 10(4): 547-55, 1996 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-8853758

RESUMO

BACKGROUND: As many as 50% of patients with reflux symptoms have no endoscopic evidence of oesophagitis. This multicentre study was designed to assess symptom relief after omeprazole 20 mg once daily in patients with symptoms typical of gastro-oesophageal reflux disease but without endoscopic evidence of oesophagitis. METHODS: Patients (n = 209) were randomized in a double-blind study to receive either omeprazole 20 mg once daily (n = 98) or placebo (n = 111) for 4 weeks. Symptoms were assessed at clinic visits and using daily diary cards, with patient-completed questionnaires providing additional data on symptoms and on psychological disturbance. RESULTS: On completion, symptom relief favoured omeprazole: 57% of patients on omeprazole were free of heartburn (vs. 19% on placebo), 75% were free of regurgitation (47%) and 43% were completely asymptomatic (14%), each with P < 0.0001. Fewer patients in the omeprazole group required alginate/antacid relief medication (P < 0.05). Symptom relief (time to first heartburn-free day) was more rapid with omeprazole (2 vs. 5 days on placebo; P < 0.01). A greater reduction in anxiety occurred in the omeprazole group (P < 0.05). CONCLUSION: Omeprazole 20 mg once daily is effective in providing relief of the symptoms typical of gastro-oesophageal reflux disease in patients with essentially normal oesophageal mucosa.


Assuntos
Esofagite Péptica/tratamento farmacológico , Antagonistas dos Receptores H2 da Histamina/uso terapêutico , Omeprazol/uso terapêutico , Adulto , Método Duplo-Cego , Feminino , Humanos , Masculino , Pessoa de Meia-Idade
10.
Aliment Pharmacol Ther ; 10(4): 637-44, 1996 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-8853770

RESUMO

AIM: To determine the effect of Helicobacter pylori eradication with omeprazole and amoxycillin, with or without metronidazole, on the 12-month course of duodenal ulcer disease. METHODS: In a randomized; double-blind study, conducted in 19 hospitals, 105 H. pylori positive duodenal ulcer patients were healed and symptom-free following either omeprazole dual therapy (omeprazole 40 mg o.m.+amoxycillin 500 mg t.d.s., OA, eradication rate 46%, n = 52) or omeprazole triple therapy (omeprazole 40 mg o.m.+amoxycillin 500 mg t.d.s.+metronidazole 400 mg t.d.s., OAM, eradication rate 92%, n = 53) for 2 weeks, followed by 2 weeks of omeprazole 20 mg o.m. and a 12-month untreated follow-up period, after which time all patients were endoscoped. Endoscopic and symptomatic relapse rates, and effect on H. pylori status measured using 13C-urea breath test, were determined. RESULTS: During the 12-month untreated follow-up period, the life-table endoscopic relapse rates were 12% (95% CI: 2-22%) and 2% (95% CI: 0-6%) for OA and OAM patients, respectively. By 12 months, life-table symptomatic relapse rates were 22% (95% CI: 13-37%) and 19% (95% CI: 8-30%) for OA and OAM, respectively. In the 12 months untreated follow-up period, 2/69 (3%, 95% CI: 0-7%) patients rendered H. pylori negative had an endoscopic relapse at the end of the 12-month follow-up period, compared with 5/31 (16%, 95% CI: 3-29%) patients remaining H. pylori positive (P = 0.03 between H. pylori positive and negative groups). Twelve of 69 (17%, 95% CI: 8-26%) patients rendered H. pylori negative relapsed symptomatically, compared with 9/31 (29%, 95% CI: 13-45%) patients remaining H. pylori positive (P = N.S. between groups). There was a significant improvement in epigastric pain (P = 0.0001), nausea and vomiting (P < 0.05) between entry to the study and 1, 6 and 12 months post-treatment for both treatment groups. CONCLUSIONS: OAM eradicates H. pylori in significantly more patients than OA, but successful H. pylori eradication with either OAM or OA predisposes to low endoscopic and symptomatic relapse rates for duodenal ulcer patients when followed up for 12 months.


Assuntos
Amoxicilina/uso terapêutico , Antiulcerosos/uso terapêutico , Úlcera Duodenal/tratamento farmacológico , Infecções por Helicobacter/tratamento farmacológico , Helicobacter pylori/efeitos dos fármacos , Metronidazol/uso terapêutico , Omeprazol/uso terapêutico , Penicilinas/uso terapêutico , Adulto , Quimioterapia Combinada , Úlcera Duodenal/patologia , Gastroscopia , Humanos , Recidiva
12.
Gut ; 36(4): 492-8, 1995 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-7737552

RESUMO

This study determined the optimal maintenance dose of omeprazole in reflux oesophagitis. One hundred and ninety three patients rendered asymptomatic and healed after four or eight weeks omeprazole were randomised double blind to 10 mg omeprazole once daily (n = 60 evaluable), 20 mg omeprazole once daily (n = 68), or placebo (n = 62) for one year or until symptomatic relapse. Each omeprazole regimen was superior to placebo in preventing both symptomatic relapse (life table analysis, p < 0.001) and endoscopically verified relapse (p < 0.001). At 12 months, the life table endoscopic remission rates (proportions of patients without grade > or = 2 oesophagitis) were: 50% (95% confidence intervals 34 to 66%) with 10 mg omeprazole once daily, 74% (62 to 86%) with 20 mg omeprazole once daily, and 14% (2 to 26%) with placebo. At 12 months, the life table symptomatic remission rates (proportions of patients asymptomatic or with mild symptoms) were: 77% (64 to 89%) with 10 mg omeprazole once daily, 83% (73 to 93%) with 20 mg omeprazole once daily, and 34% (16 to 52%) with placebo. Both 10 mg and 20 mg omeprazole once daily were effective in prolonging the remission of reflux oesophagitis: 10 mg may be appropriate to start longterm treatment, though the existence of a dose response relation means that 20 mg once daily may be effective in patients for whom 10 mg once daily is suboptimal.


Assuntos
Esofagite Péptica/prevenção & controle , Omeprazol/administração & dosagem , Adulto , Idoso , Idoso de 80 Anos ou mais , Relação Dose-Resposta a Droga , Método Duplo-Cego , Esquema de Medicação , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Omeprazol/efeitos adversos , Recidiva , Fatores de Tempo , Resultado do Tratamento
13.
Artif Organs ; 18(11): 793-6, 1994 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-7864725

RESUMO

The dominant problem in the design of an intracorporeal oxygenator is achieving gas transfer rates sufficient for physiological needs in the space available with acceptably low flow resistance to blood. Design problems still to be solved, when configurations with sufficient gas transfer effectiveness are well identified, are biological tolerance (including adequate blood compatibility), ease of manufacture, and prolonged function.


Assuntos
Oxigenadores , Animais , Órgãos Artificiais , Desenho de Equipamento , Hemorreologia , Humanos , Pulmão , Próteses e Implantes
14.
Artif Organs ; 18(11): 797-800, 1994 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-7864726

RESUMO

The woven tubes membrane oxygenator is a suitable configuration for the intracorporeal membrane oxygenator because of a high gas exchange performance and a compact packing of tubing. In this study the oxygen transfer performance of woven tubes was evaluated by an in vitro experiment with an external perfusion mode; the blood flow is outside of the tubes in order to reveal the feasibility of designing the intravascular oxygenator (IVOX) by the woven tubes. The oxygen transfer efficiency of the external perfusion mode is superior to that with the internal perfusion mode because of the larger convective mixing effect on the external surface of the tubes. Thus the use of the external perfusion mode results in the shorter necessary tube length for the rated condition, which enables making the oxygenator unit more compact. All of these features encourage the adoption of the woven tubes for use in the intravascular oxygenator.


Assuntos
Intubação/instrumentação , Oxigênio/sangue , Oxigenadores de Membrana , Animais , Velocidade do Fluxo Sanguíneo/fisiologia , Gasometria , Bovinos , Desenho de Equipamento , Estudos de Viabilidade , Hemorreologia , Metilmetacrilato , Metilmetacrilatos , Modelos Anatômicos , Politetrafluoretileno , Próteses e Implantes , Fluxo Sanguíneo Regional/fisiologia , Propriedades de Superfície , Veias Cavas/fisiologia
15.
Respir Med ; 88(4): 293-9, 1994 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-8036292

RESUMO

In a double-blind, randomized, parallel-group clinical trial, 340 asthmatic patients aged 12-70 years received budesonide 400 micrograms once daily in the morning, budesonide 400 micrograms once daily in the evening, budesonide 200 micrograms twice daily or placebo, for 12 weeks in addition to inhaled short-acting beta 2-agonists used as required (p.r.n.). Budesonide was given as Pulmicort Turbohaler. Peak expiratory flow rate (PEFR) increased by 20 to 30 1 min-1 in each of the active treatment groups, significantly more than in the placebo group (P < 0.01). There were no significant differences between the active treatment groups. Symptom improvement and decreased beta 2-agonist use reflected the PEFR data. Incidences of adverse events in the active treatment groups were similar to those observed in the placebo group. Budesonide 400 micrograms given once daily morning or evening is equieffective with the same total daily dose given twice daily in the treatment of mild to moderate stable asthmatics.


Assuntos
Asma/prevenção & controle , Glucocorticoides/administração & dosagem , Nebulizadores e Vaporizadores , Pregnenodionas/administração & dosagem , Adolescente , Adulto , Idoso , Asma/fisiopatologia , Budesonida , Método Duplo-Cego , Esquema de Medicação , Feminino , Humanos , Pulmão/fisiopatologia , Masculino , Pessoa de Meia-Idade , Pico do Fluxo Expiratório/efeitos dos fármacos
16.
Basic Res Cardiol ; 89 Suppl 1: 33-9, 1994.
Artigo em Inglês | MEDLINE | ID: mdl-7945174

RESUMO

Unstable plaques are undergoing thrombosis which, in most instances, is due to fissuring and rupture of the plaque cap. This process (deep intimal injury) is a complication of plaques with a lipid-rich core. The cap tear allows blood to enter the core from the lumen, leading initially to intraplaque thrombosis and, subsequently, in some cases intraluminal thrombosis. Cap tears reflect the interplay between the force exerted on the tissue and its inherent mechanical strength. Factors which elevate and concentrate circumferential wall stress on the cap during systole include an increasing proportion of the total plaque volume occupied by the lipid core, thinning of the cap and a loss of internal collagen struts within the core. Factors which lead to an inherent reduction in the mechanical strength of cap tissue include a reduction in collagen and glycosaminoglycan concentrations, an increase in the number and density of macrophages, and a concomitant reduction in smooth muscle cells in the cap tissue. It is therefore possible to define a vulnerable plaque as one in which the lipid core is disproportionately large, the cap thin, and in which monocytes preponderate over smooth muscle cells.


Assuntos
Arteriosclerose/fisiopatologia , Lipídeos/análise , Túnica Íntima/patologia , Contagem de Células , Humanos , Macrófagos/metabolismo , Macrófagos/patologia , Músculo Liso Vascular/metabolismo , Músculo Liso Vascular/patologia , Trombose/fisiopatologia , Túnica Íntima/metabolismo
17.
Aliment Pharmacol Ther ; 7(5): 501-7, 1993 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-8280818

RESUMO

This study was designed to establish whether 40 mg omeprazole once daily exhibits sufficient additional efficacy over that of 20 mg omeprazole once daily in patients with symptomatic reflux oesophagitis requiring more than an initial 4-week course of 20 mg omeprazole once daily (o.m.) to warrant routine use of the higher dose. Three hundred and thirteen patients were randomized to receive either 20 mg omeprazole (4 weeks) then 20 mg (second 4 weeks if not both healed and symptom-free after 4 weeks), or 20 mg omeprazole (4 weeks) then 40 mg omeprazole o.m. (second 4 weeks). One hundred and twenty-seven patients were healed and symptom-free after 4 weeks and left the study at that point. Taking the second treatment period in isolation, the healing rate (64% vs. 45%, P < 0.02) and relief of heartburn (72% vs. 60%, P < 0.002) were greater among patients receiving 40 mg omeprazole o.m., demonstrating the existence of a dose-response relationship for omeprazole. However, on completion, there were no significant differences between the patients randomized to the 20/20 mg (healed 65%, asymptomatic 69%) or the 20/40 mg (healed 74%, asymptomatic 74%: both not significant differences compared with 20/20 mg) regimens. The magnitude of the difference in efficacy between 20 and 40 mg omeprazole in symptomatic reflux oesophagitis is insufficient to warrant the routine use of 40 mg in patients requiring more than 4 weeks' treatment with 20 mg omeprazole o.m.; continued treatment with 20 mg omeprazole for 4-8 weeks is the preferred option.


Assuntos
Esofagite Péptica/tratamento farmacológico , Omeprazol/administração & dosagem , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Relação Dose-Resposta a Droga , Esquema de Medicação , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Omeprazol/efeitos adversos , Omeprazol/uso terapêutico
18.
Br Heart J ; 69(5): 377-81, 1993 May.
Artigo em Inglês | MEDLINE | ID: mdl-8518056

RESUMO

OBJECTIVE: To assess the size of the lipid pool and the number of smooth muscle cells and monocyte/macrophages in human aortic plaques that were intact and to compare the results with those in aortic plaques undergoing ulceration and thrombosis. DESIGN: The lipid pool was measured as a percentage of the total cross sectional area of the plaque. Immunohistochemistry was used to identify cell types (monocytes/macrophages (M phi) by EBM11 and HAM56, smooth muscle cells by alpha actin). The area of the tissue occupied by each cell type was measured by quantitative microscopy in the peripheral (shoulder) area of the plaque and the plaque cap. Absolute counts of each cell type were expressed as the ratio of SMC:M phi. MATERIAL: Aortas were obtained at necropsy from men aged less than 69 years who died suddenly (within 6 hours of the onset of symptoms) of ischaemic heart disease. 155 plaques from 13 aortas were studied. Four aortas showed intact plaques only (group A, n = 31). Nine aortas showed both intact plaques (group B, n = 79) and plaques that were undergoing thrombosis (group C, n = 45). RESULTS: In 41 (91.1%) of the 45 plaques undergoing thrombosis (group C) lipid pools occupied more than 40% of the cross sectional area of the plaque. Only 12 (10.9%) of the 110 intact plaques (groups A + B) had lipid pools of this size. The mean size of the lipid pool in plaques of groups A, B, and C was 12.7%, 27.3% and 56.7% respectively. Compared with intact plaques those undergoing thrombosis contained a smaller volume of smooth muscle cells (2.8% v 11.8%) and a larger volume of monocyte/macrophages (13.7% v 2.9%) in the plaque cap. The ratio of the number of smooth muscle cells to monocytes/macrophages was 7.8 in group A plaques, 4.1 in group B plaques, and 1.0 in group C plaques. This gradient was the result of an absolute increase in monocyte/macrophages and an absolute decrease in smooth muscle cells. CONCLUSIONS: In the aorta ulceration and thrombosis were characteristic of plaques with a high proportion of their volume occupied by extracellular lipid, and in which there was a shift toward a preponderance of monocyte/macrophages compared with smooth muscle cells in the cap.


Assuntos
Arteriosclerose/complicações , Trombose/etiologia , Idoso , Aorta/química , Aorta/patologia , Arteriosclerose/patologia , Contagem de Células , Humanos , Imuno-Histoquímica , Lipídeos/análise , Macrófagos/patologia , Masculino , Músculo Liso Vascular/patologia , Fatores de Risco
19.
J Biomed Eng ; 15(1): 27-33, 1993 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-8419677

RESUMO

The tearing of the cap of atheromatous plaques is the commonest cause of thrombosis in human coronary arteries. It has been proposed that tearing arises because of structural weakening of the cap's connective tissue around the tear. To test this hypothesis we compared the mechanical properties of the intact edges of torn plaque caps and unbroken caps. Owing to limitations in plaque size, a purpose-built tensometer was developed to study stress-strain relationships of the small connective tissue specimens. The design of the tensometer is reported and was shown to detect accurately, minor differences in connective tissues and to generate complete stress-curves with computer-assisted image analysis.


Assuntos
Arteriosclerose/fisiopatologia , Tecido Conjuntivo/fisiopatologia , Modelos Cardiovasculares , Estresse Fisiológico/fisiopatologia , Animais , Aorta Abdominal/efeitos dos fármacos , Aorta Abdominal/fisiologia , Fenômenos Biomecânicos , Catequina/farmacologia , Colágeno/fisiologia , Feminino , Humanos , Processamento de Imagem Assistida por Computador , Microcomputadores , Ratos , Fenômenos Fisiológicos da Pele , Resistência à Tração/efeitos dos fármacos
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