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Search Results: 1 - 10 of 3139 matches for " Adamastor Humberto; "
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Ruptura dos vasa vasorum e hematoma intramural da aorta: um paradigma em mudan?a
Pereira, Adamastor Humberto;
Jornal Vascular Brasileiro , 2010, DOI: 10.1590/S1677-54492010000200008
Abstract: rupture of vasa varorum has been recognized as one cause of intramural hematoma of the aorta for 90 years. this brief revision presents systematically, the physiology of these vessels and its role in the physiopathology of the alterations in the aortic wall secondary to hypertension, arteriosclerosis and in acute aortic syndrome. the hypothesis is that rupture of vasa vasorum is a secondary phenomenon and not one causal factor in the physiopathology of intramural hematoma.
Angioplastia da carótida versus endarterectomia: o velho e o novo Carotid angioplasty versus endarterectomy: the old and the new
Adamastor Humberto Pereira
Jornal Vascular Brasileiro , 2006, DOI: 10.1590/s1677-54492006000300003
Abstract:
Modelos animais de aneurisma de aorta
Argenta, Rodrigo;Pereira, Adamastor Humberto;
Jornal Vascular Brasileiro , 2009, DOI: 10.1590/S1677-54492009000200009
Abstract: experimental animal models have been used in vascular surgery for decades. the development of new interventional techniques in the endovascular treatment of aneurysms requires the creation of good experimental models to test these devices and study their impact on disease progression. the aim of this article was to review arterial aneurysm models currently available. several distinct models have been described but none of them satisfies all the requirements of an ideal aneurysm model. large animal models are appropriate for training, study of alterations in physiological parameters during and after device delivery, and integration of this device in the vessel wall. significant disadvantages include difficulty in handling, high costs, difficult maintenance, and government regulations, hindering the availability of several animal species. small animal models, such as rabbits and mice, despite being inexpensive and easily available, are not appropriate for studies of endovascular techniques because of their small-diameter vessels. to date, none of the models described could mimic all features of human aneurysms. in this review, we describe the available models and discuss their advantages and limitations.
Digital morphometric analysis of the aortic wall in pigs following implantation of dacron-covered stents versus non-covered stents
Dutra, Clandio de Freitas;Pereira, Adamastor Humberto;
Acta Cirurgica Brasileira , 2004, DOI: 10.1590/S0102-86502004000300006
Abstract: purpose: to evaluate, by digital morphometry, the intimal thickening after the placement of two different kinds of stents: polyester covered stainless steel stents (dacron) and non-covered stents implanted in young pigs' infrarenal aortas. methods: the experiment was carried out on two separate groups of pigs. eight polyester-covered stainless steel stents (dacron) and eight stainless steel stents (30-mm long, 8-mm diameter) were deployed through extraperitoneal approach in the normal infrarenal aorta of 16 normolipemic pigs. to allow the passage of the delivery system, a small arteriotomy was performed (phase i). after four weeks, the aorta with the stent was removed en bloc. (phase ii). the values of the hematimetric and lipid analysis did not show any changes that could influence the study. tissue samples of the fixing sites (proximal and distal) of the stents were taken. microscope slices were prepared and submitted to verhoeff's hematoxilin and eosin techniques and sent to morphometric analysis. results: the intima immediately proximal to the device was thicker in the group of covered stents with marginal significance (p=0.054). the distal intimal layer (p=0.185), proximal medial layer of the proximal portion (p=0.141) and distal portion (p=0.375) did not present statistical difference between the two groups. conclusions: patency was 100% in both groups of these normolipemic pigs. after four weeks the intimal layer immediately proximal to the covered stents was ticker when compared to uncovered stents, but this had a borderline significance. the intimal layer distal to covered stents and the media proximal or distal to the devices had similar morphometric features when covered and uncovered stents where compared.
Digital morphometric analysis of the aortic wall in pigs following implantation of dacron-covered stents versus non-covered stents
Dutra Clandio de Freitas,Pereira Adamastor Humberto
Acta Cirurgica Brasileira , 2004,
Abstract: PURPOSE: To evaluate, by digital morphometry, the intimal thickening after the placement of two different kinds of stents: polyester covered stainless steel stents (Dacron) and non-covered stents implanted in young pigs' infrarenal aortas. METHODS: The experiment was carried out on two separate groups of pigs. Eight polyester-covered stainless steel stents (Dacron) and eight stainless steel stents (30-mm long, 8-mm diameter) were deployed through extraperitoneal approach in the normal infrarenal aorta of 16 normolipemic pigs. To allow the passage of the delivery system, a small arteriotomy was performed (phase I). After four weeks, the aorta with the stent was removed en bloc. (phase II). The values of the hematimetric and lipid analysis did not show any changes that could influence the study. Tissue samples of the fixing sites (proximal and distal) of the stents were taken. Microscope slices were prepared and submitted to Verhoeff's hematoxilin and eosin techniques and sent to morphometric analysis. RESULTS: The intima immediately proximal to the device was thicker in the group of covered stents with marginal significance (p=0.054). The distal intimal layer (p=0.185), proximal medial layer of the proximal portion (p=0.141) and distal portion (p=0.375) did not present statistical difference between the two groups. CONCLUSIONS: Patency was 100% in both groups of these normolipemic pigs. After four weeks the intimal layer immediately proximal to the covered stents was ticker when compared to uncovered stents, but this had a borderline significance. The intimal layer distal to covered stents and the media proximal or distal to the devices had similar morphometric features when covered and uncovered stents where compared.
Atualiza??o sobre endopróteses vasculares (stents): dos estudos experimentais à prática clínica
Fran?a, Luís Henrique Gil;Pereira, Adamastor Humberto;
Jornal Vascular Brasileiro , 2008, DOI: 10.1590/S1677-54492008000400010
Abstract: the treatment of peripheral vascular diseases is one of the most rapidly expanding fields of medicine today. the number of peripheral interventions increased and innovative endovascular techniques are close to the results of traditional vascular surgeries. although balloon angioplasty alone offers good immediate results, implantation of stents has been proposed to improve the procedural success and extend its application to more patients with peripheral vascular disease. however, stenting is controversial. use of stents has good results in aortoiliac vessels, but its use in femoropopliteal vessels is still in dispute. moreover, the rapid development of endovascular stents for peripheral applications and their choice have been a complicated task for endovascular surgeons. many factors influence choice of stent, therefore, knowledge of available stents is mandatory. appropriate selection depends on adequate preprocedural evaluation of the lesion, choice of primary vs. selective stent placement, and location and characteristics of the lesion. in this article the history of stent development is reviewed, from studies with experimental models to clinical practice, and its application in the treatment of peripheral vascular diseases is discussed.
Morphometric analysis of intimal thickening secondary to stent placement in pig carotid arteries
Pasa, Márcio Bastiani;Pereira, Adamastor Humberto;Castro Júnior, Cyro;
Acta Cirurgica Brasileira , 2008, DOI: 10.1590/S0102-86502008000200009
Abstract: objective: to evaluate intimal thickening secondary to stent placement or to insertion of the delivery system without stent placement in pig carotid arteries. methods: stents were placed in the right common carotid arteries of 7 pigs, and 7 other control pigs underwent only insertion of the delivery system without stent placement. uninjured contralateral common carotid arteries of the two groups were also used as controls. samples of arterial tissue, obtained from the area adjacent to the distal segment of the stent four weeks after placement, underwent morphometric analysis. morphometric data were compared with findings for arterial samples from injured arteries of the control group and uninjured contralateral arteries of the two groups. the unpaired mann-whitney u test and the wilcoxon t test for nonparametric samples were used for statistical analysis. results: greater intimal thickening was found in the group in which stents were placed (p=0.008). changes in luminal area and media layer were not significantly different between the two groups. the comparison of contralateral carotid arteries of the two groups revealed significant changes in intimal and luminal areas. no statistically significant changes were found in medial layer area. conclusions: all arteries that underwent stent placement showed intimal thickening without changes in the tunica media at four weeks. dissection and insertion of the delivery system without stent placement was associated with a lesser degree of intimal thickening.
Morphometric analysis of the intimal reaction after stent implantation in iliac arteries submitted to angioplasty in pigs
Castro Júnior, Cyro;Pereira, Adamastor Humberto;Pasa, Márcio Bastiani;
Acta Cirurgica Brasileira , 2006, DOI: 10.1590/S0102-86502006000300004
Abstract: purpose: to compare through digital morphometry, the intimal thickening of the common ilíac arteries (cia) in pigs, submitted to angioplasty and angioplasty followed by stent implantation. methods: angioplasty was performed in 10 pigs in both cia, followed by a stent implantation in the left cia. after four weeks, the aorto-iliac segment was dissected. histologic slices where divided in three groups: left cia in the area of the proximal (group 1) and distal (group 2) implantation site of the stent and the region of angioplasty in the right cia (group 3). the histological slices were digitalized to be analyzed by morphometry with calculation of the luminal, intimal and media layers areas. descriptive statistics analysis was performed through average and standard deviation of areas on each group, using anova, with lsd post-hoc test (p<0.05). results: a significant statistic difference was observed when the median area of intimal layer of the groups 1 and 2 where compared with group 3 and in the media layer area of the groups 1 and 2 when compared with group 3. no difference was observed in luminal areas among the three groups. conclusion: angioplasty followed by stent insertion produces an intimal thickening larger than that observed after simple angioplasty. however, the area of the media layer is smaller in the "angioplasty plus stent" group and there is no significant change in the luminal area among the three groups.
Self-expandable nitinol stent placement in homocysteinemic porcine aorta
Fran?a, Luís Henrique Gil;Pereira, Adamastor Humberto;Perini, Sílvio César;
Clinics , 2008, DOI: 10.1590/S1807-59322008000200012
Abstract: purpose: to compare aortic intimal thickening of normal and hyperhomocysteinemic pigs (induced with a methionine-rich diet) following placement of a self-expanding nitinol stent. methods: eighteen macau pigs were used. they were older than eight weeks in age and had an average weight of 30 kg. pigs were randomly divided into two groups. the first, group c (control), was fed a regular diet, and the second group, group m, was fed a methionine-rich diet for 30 days to induce hyperhomocysteinemia. the self-expandable nitinol stents were 25mm in length and 8 mm in diameter after expansion. blood samples were collected to measure total cholesterol, triglycerides, hdl and homocysteine concentrations. all animals were subjected to angiography. thirty days after the procedure, the animals were sacrificed, and the abdominal aorta was removed for histological and digital morphometry analysis. results: under microscopic evaluation, the intima was significantly thicker in group c than in group m. when groups were compared by digital morphometric analysis, intimal thickening of the vessel wall was higher in group c than in group m. there was no significant change in total cholesterol, triglycerides or hdl concentrations in either group. in group c the levels of plasma homocysteine ranged from 14,40 to 16,73μmol/l; in group m, plasma homocysteine levels ranged from 17.47 to 59.80 μmol/l after 30 days of a methionine-rich diet. conclusion: compared to normal pigs, less intimal hyperplasia was observed in the abdominal aortas of hyperhomocysteinemic pigs thirty days after the insertion of a self-expandable nitinol stent.
Momento ideal para a endarterectomia de carótida após um AVC recente
Oderich, Gustavo S. C.;Francisconi, Alessandra Bastian;Francisconi, Clovis Roberto M.;Pereira, Adamastor Humberto;
Revista do Colégio Brasileiro de Cirurgi?es , 2001, DOI: 10.1590/S0100-69912001000400009
Abstract: recent randomized clinical trials have confirmed the role of carotid endarterectomy in the prevention of a second stroke in patients with a recent stroke and severe carotid stenoses. however, the timing of the operation is still controvertial. early surgery has been associated with cerebral hemorrhage and infarct extension. delayed endarterectomy exposes the patient to recurrent stroke and carotid occlusion. the clinical studies addressing this problem are retrospective and nonrandomized. in the absence of a prospective randomized trial comparing early and late surgery, one approach to interpreting the surgical studies is to compare them with the natural history of stroke. the authors describe the rationale for early surgery, the natural history of ischemic strokes and the risk factors associated with perioperative strokes in patients undergoing endarterectomy.
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