RESUMO
Titanium powder production by the hydride-dehydride method has been developed as a non-expensive process. In this work, commercially pure grade two Ti specimens were hydrogenated. The hydrided material was milled in a planetary mill. The hydrided titanium powder was dehydrided and then sieved to obtain a particle size between 37 and 125 microm in order to compare it with a commercial powder produced by chemical reduction with a particle size lower than 150 microm. Cylindrical green compacts were obtained by uniaxial pressing of the powders at 343 MPa and sintering in vacuum. The powders and the density of sintered compacts were characterized, the oxygen content was measured and in vivo tests were performed in the tibia bones of Wistar rats in order to evaluate their biocompatibility. No differences were observed between the materials which were produced either with powders obtained by the hydride-dehydride method or with commercial powders produced by chemical reduction regarding modifications in compactation, sintering and biological behaviour.
Assuntos
Materiais Biocompatíveis/química , Materiais Biocompatíveis/farmacologia , Tíbia/citologia , Tíbia/efeitos dos fármacos , Titânio/química , Titânio/farmacologia , Animais , Cristalização/métodos , Masculino , Teste de Materiais , Tamanho da Partícula , Pós , Ratos , Ratos Wistar , Propriedades de SuperfícieRESUMO
We examined antioxidant actions in 73 patients undergoing coronary artery surgery by assessing mitochondrial damage and oxidative stress in ventricular biopsies obtained at preischemia and postreperfusion. Those patients who received antioxidant therapy benefited by less oxidative stress and mitochondrial damage.
Assuntos
Antioxidantes/uso terapêutico , Ponte de Artéria Coronária/efeitos adversos , Mitocôndrias/patologia , Estresse Oxidativo , Complicações Pós-Operatórias/prevenção & controle , Humanos , Pessoa de Meia-Idade , Complicações Pós-Operatórias/patologiaRESUMO
Atherosclerosis is the most frequent cause of death in industrialized countries. Lesions are characterized by lipid deposits, focal thickening of the arterial wall with proliferation of smooth muscle cells (SMC), mononuclear infiltrates and neoformed vessels. In this paper, we studied the proliferative characteristics and cytogenetic alterations of SMC. These cells, expressing specific muscular actin, were diploid with an increased proliferative index for PCNA. A high percentage of SMC showed intense expression of p53. There were signs of chromosomal instability, being the most frequent findings chromosome 7 trisomy and chromosome 11 monosomy. Additionally, the gene for FGF-3 showed a marked amplification. These findings strongly suggest that SMC proliferation is active, and is related to the accumulation or mutation of the p53 oncoprotein. It also presents specific chromosomal alterations in close relation with growth factors. According to these findings SMC hyperplasia in the atherosclerosis plaque may be considered as a cellular clonal expansion.
Assuntos
Arteriosclerose/genética , Cromossomos Humanos 6-12 e X/genética , Músculo Liso , Proteínas Nucleares/genética , Arteriosclerose/patologia , Cromossomos Humanos Par 11/metabolismo , Cromossomos Humanos Par 7/genética , Fator 3 de Crescimento de Fibroblastos , Fatores de Crescimento de Fibroblastos/genética , Humanos , Hibridização in Situ Fluorescente , Músculo Liso/patologia , Proteínas Proto-Oncogênicas/genética , Trissomia , Proteína Supressora de Tumor p53/genéticaRESUMO
Atherosclerosis is the most frequent cause of death in industrialized countries. Lesions are characterized by lipid deposits, focal thickening of the arterial wall with proliferation of smooth muscle cells (SMC), mononuclear infiltrates and neoformed vessels. In this paper, we studied the proliferative characteristics and cytogenetic alterations of SMC. These cells, expressing specific muscular actin, were diploid with an increased proliferative index for PCNA. A high percentage of SMC showed intense expression of p53. There were signs of chromosomal instability, being the most frequent findings chromosome 7 trisomy and chromosome 11 monosomy. Additionally, the gene for FGF-3 showed a marked amplification. These findings strongly suggest that SMC proliferation is active, and is related to the accumulation or mutation of the p53 oncoprotein. It also presents specific chromosomal alterations in close relation with growth factors. According to these findings SMC hyperplasia in the atherosclerosis plaque may be considered as a cellular clonal expansion.
RESUMO
This review deals with tobacco-associated cardiovascular effects and diseases. The importance of tabaccoism in primary care, its effects on cardiovascular, and immunology system and hemostasia, as well as, the role of smoking in atherosclerosis, coronary heart disease, acute myocardial infarct, diabetes, and other alterations are discussed. Finally we summarize the general tobacco control policies and the methods to achieve smoking cessation. Although it is well established the causal relationship between smoking and disease, and the general public is aware of this, the cardiologist's involvement and commitment is of utmost importance.
Assuntos
Doenças Cardiovasculares/induzido quimicamente , Fumar/efeitos adversos , Argentina/epidemiologia , Cardiologia , Doenças Cardiovasculares/epidemiologia , Doenças Cardiovasculares/mortalidade , Humanos , Morbidade , Papel do MédicoRESUMO
PURPOSE: To evaluate electrocardiographic data of Cebus apella monkeys with Chagas' disease. MATERIAL AND METHODS: 53 Cebus apella monkeys (juvenile and adult of both sexes) were used: 35 as a control group and 18 inoculated four-five years ago with 3 different Trypanosoma cruzi strains (CA1, n = 10; Colombian, n = 4; Tulahuen, n = 4). RESULTS: The normal electrocardiogram (ECG) showed differences with that of man, a) high cardiac rate; b) presence of "pulmonary p" wave without pulmonary pathology. The ECT alterations found between 11 and 58 months after last inoculation were: right bundle branch block; intermittent right bundle branch block; left ventricle overload; repolarization disturbances; left anterior hemiblock; extra systole. These alterations resemble those found in humans, as well as clinical parasitological and immunological alterations. Their incidence and the time at which they appeared, seem to vary according to the route, strain, inoculum and frequency of the inoculation. Three of the monkeys died spontaneously 46, 48 and 52 months after the infections due to the natural evolution of the disease, and six were sacrificed during the follow-up. In both cases histopathological lesions were found, and their intensity was directly related to the time and resembled the human disease. CONCLUSION: The Cebus apella, as it reproduces human electrocardiographic and histopathological alterations, a short time after experimental infection, is a suitable model for the study of the different aspects of the physiopathology, immunopathology and therapeutics of the indeterminate and chronic phases of Chagas' disease.