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Biomedical subjects

A López Bravo

Publications and source records attributed to A López Bravo.

9 recordsLinked to original sources
PubMed1999

Radiopaque acrylic cements prepared with a new acrylic derivative of iodo-quinoline.

A novel iodine-containing methacrylate, 2,5-diiodo-8-quinolyl methacrylate, has been synthesized and used in the preparation of acrylic radiopaque cements. The effect of incorporation of this monomer to the self-curing resins, on the curing parameters, swelling behaviour and mechanical properties was studied. The incorporation of the radiopaque compound 2,5-diiodo-8-hydroxyquinoline to the solid phase was also carried out for comparative experiments. A decrease in the peak temperature and an increase in the setting time was observed with the addition of the radiopaque monomer, however, the curing parameters did not appreciably change with the addition of the radiopaque compound to the solid phase. Swelling of the modified cements was in the same range as that of the radiolucent cement; however, the diffusion coefficients calculated according to the Fick's law were higher for the iodine-containing materials. The addition of 5 wt% of the iodine-containing methacrylate provided a significant increase in the tensile properties with respect to either control radiolucent formulations or BaSO4-containing formulations. Biocompatibility of the modified cements was studied by implantation of rods of the cements into rats and histological analysis of the surrounding tissue.

Animals↗
PubMed1991

Experimental thioacetamide-induced cirrhosis of the liver.

Hepatic cirrhosis is a complex disease in which several biological, biochemical and chemical alterations are combined, none of these alone being sufficient for diagnosis. The morphological characteristics of the final stages of cirrhosis are well known, but the initial lesions and intermediate stages still have not been fully clarified. An experimental model of hepatic cirrhosis by chronic administration over 30 weeks of thioacetamide (50 mg/kg twice weekly) to female Wistar rats has been produced. In a macroscopic, microscopic and ultrastructural study. The different lesions that appeared were evaluated according to the dose of the toxic agent administered up, until hepatic cirrhosis was finally installed; this was after 60 doses of the toxic agent (30 weeks). Discussion is made of the different types of administration and the doses employed to obtain a suitable survival rate for these cases; in our experiments this was 95%. It has been demonstrated in both human and experimental pathology that once the disease itself has been installed, currently there is no rational or useful treatment for it. A beneficial effect has been demonstrated for certain substances, improving the initial and intermediate lesions, so we conclude by stating that it is necessary to further study the hepatic lesions preceeding cirrhosis. Knowledge of these lesions could form the basis for establishing a useful and rational therapy for such cases.

Animals↗
PubMed1989

[Effect of (+) cyanidanol-3 on experimental liver cirrhosis induced by carbon tetrachloride].

Liver cirrhosis is a very common illnesses and currently its treatment remains unpromising. In a research line devoted to studying the hepatotoxicity of certain substances we have evaluated the lesions that appear prior to the occurrence of cirrhosis and hepatocarcinoma in order to test, in different assays liver-protecting substances such as cyanidanol-3 that have been seen to lead to an improvement in morphological alterations in the liver and even to reverse such lesions. The mechanisms of action of this compound are discussed. The authors believe that considerable work remains to be carried out but that some day some liver-protecting substances that yield good experimental results may be applied to clinical situations.

Animals↗
PubMedDate not supplied

[Acquired stenosis of the nasopharynx].

A case of scarring stenosis of the nasopharynx occurring in the fifth decade without previous medical history is presented. Transpalatal resection with a prolonged stent, produced patent nasal cavities, but the different studies performed did not establish the etiological diagnosis. A final stage of rhinoscleroma was suspected.

Female↗
PubMedDate not supplied

[The effects of a benzopyrone derivative in experimental brain edema due to cold in the rabbit].

On this study, parenchymal changes during a cerebral edema caused by thermic injury (cool) on the rabbit, are analyzed. The work was based on the ultrastructural findings obtained by transmission electronic microscopy and on the effects produced by a benzopironic derived (F-117 Hydrosmina). The injury was produced with solid CO2, previous a craniectomy, on the dura mater of the left hemisphere. Forty rabbits were included into the study, the animals were distributed into five groups (n = 8): a control group and 4 treatment groups. One of the groups received treatment without previous cerebral injury. The group of rabbits with doses of 50 mg/Kg of weight showed focal and diffuse areas of edema alternating with less damaged areas, the edema was evident on the white substance. This group also showed a dissociation of the myelinic fibers and an intracytoplasmatic tumefaction into the glial cells. These findings contrast with the histopathological findings obtained from the rabbits (V), the extracellular edema was poor, the myelinic fiber disorganization was minimal with no vacuolar degeneration and no structural mitochondrial changes had been showed. The discontinuance of the hematoencephalic barrier caused by the cool could be a possible mechanism that causes the opening of the endothelial unions from the capillary vessels, changing their membranes and resulting in a free penetration of the molecule into the cerebral parenchyma.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗