120 resultados para Corneal diseases


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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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The objective of this study was to examine the endothelial surface morphology and to perform morphometric analysis of the corneal endothelial cells of Yacare caiman (Caiman yacare) using scanning electron microscopy. Morphometric analysis with regard to polygonality, mean cell area, cell density and coefficient of variation of mean cell area was performed. Cell areas were measured using image analysis software. The normal corneal endothelium of Yacare caiman consisted of polygonal cells of uniform size and shape with interdigitations of the cell borders. Microvilli appeared as protrusions on the cellular surface. The average cell area was 270 +/- 24 mum(2) and the endothelial cell density was 3704 +/- 324 cells/mm(2). The coefficient of variation of cell area was 0.22. This study demonstrates that the Yacare caiman corneal endothelium is similar to those described in other vertebrates.

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Parasitic diseases in humans, transmitted by insects, affect about 500 million people living mainly in countries of low economic power, the control of these diseases is difficult to carry out, mainly die to social and political problems, enhanced bg the capacity of these organisms to develop resistance to insecticides used to for their destruction.Some recent advances in the area of insect immunology have open the possibility for abetter epidemiological control of these diseases.The immune system of these insects, as well as that of other organisms, have the ability to recognize the infecting parasites and liberate a series of reactions which stop the infection. These reactions involve the circulating cells (hemocytes) against the parasite. These cells have the ability of phagocytize and liberate the production of various humoral factors, neutralizing the infection.Some promising results, obtained by the study of the immune system of malaria-transmitting insects, the sleeping disease, and dengue, are an example of this new sanitary strategy.

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Previous studies have shown that long-term alcohol treatment has negative effects on prostatic stromal-epithelial interaction. Thus, the aim of the present study was to analyze the histochemical, immunohistochemical and ultrastructural alterations that occur in the prostatic stroma and epithelium of rats submitted to chronic alcohol ingestion and alcohol abstinence, as well as to establish the relationship between these changes and prostatic diseases. Thirty male rats (10 Wistar and 20 UChB rats) were divided into three experimental groups: the control group received tap water, the alcoholic group received ethanol diluted to 10 degrees G.L. for 150 days, and the abstinent group received the same liquid diet as the alcoholic group up to 120 days of treatment and only tap water for 30 days thereafter. At the end of treatment, all animals were sacrificed and the ventral lobe of the prostate was removed and processed for histochemical, immunohistochemical and ultrastructural analyses. In addition, plasma testosterone levels were measured. The results showed, prostatic intraepithelial neoplasia, infolding of the epithelium towards the stroma, stromal hypertrophy and the presence of inflammatory cells in alcoholic animals. In the abstinent group, alterations were noted mainly in the stromal area. In conclusion, ethanol triggers alterations in prostatic epithelial and stromal compartments, affecting the stromal microenvironment and predisposing the organ to pathological processes. (C) 2006 International Federation for Cell Biology. Published by Elsevier Ltd. All rights reserved.

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Background: Detection of systemic inflammation, which is important for proper diagnosis and prompt treatment, can be challenging.Hypothesis: Measurement of plasma iron concentration is a sensitive method for detecting systemic inflammation in horses compared with measurements of plasma Fibrinogen concentration, a traditional marker for inflammation in the horse.Animals: Ninety-seven horses hospitalized with diseases causing systemic inflammation, 22 horses with localized inflammation, and 12 clinically normal horses were included in this study.Methods: A retrospective study was made on hospitalized horses that had both plasma iron and fibrinogen concentrations measured on hospital admission.Results: Plasma iron concentration was lower in horses with systemic inflammation (64 +/- 45 mu g/dL) than the reference interval minimum (105 mu g/dL) and were significantly lower (P = .001) than the value in a group of horses with local inflammation (123 +/- 45 mu g/dL) and in healthy transported horses (143 +/- 29 mu g/dL). Low plasma iron and high fibrinogen concentrations were both sensitive indicators of systemic inflammation in horses with sensitivity of 90 and 82%, respectively. There was a similar correlation between either continued decreases in iron concentration (R-sp of 0.239) or increases in fibrinogen concentration (R-sp of 0.280) during hospitalization and a worse prognosis.Conclusions and Clinical Importance: Measurement of plasma iron concentration better reflected acute inflammation than did fibrinogen concentration.

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Background: Thyroperoxidase is the major antigen of the thyroid microsomal antibodies (TMA) detected in autoimmune thyroid diseases. Its amino acid sequence has 44% homology with myeloperoxidase (MPO), an enzyme present in the primary granules of neutrophils and one of the major antineutrophil cytoplasmic antibodies (ANCA) antigens. The objective of the present study was to investigate the presence of cross-reactivity to MPO of TMA. Methods: We studied sera from 51 patients with autoimmune thyroid diseases, all of them TMA-positive. The presence of ANCA was investigated by indirect immunofluorescence and by capture enzyme-linked immunosorbent assay. Results: ANCA were positive in 3.9% of the TMA-positive sera and none of them reacted with MPO. In contrast, the ANCA-positive sera revealed antielastase activity. None of the ANCA-positive cases presented clinical signs of vasculitis. However, these 2 patients had been on prolonged treatment with propylthiouracil. Conclusions: We conclude that there is no cross-reactivity to MPO of TMA in patients with autoimmune thyroid diseases, possibly because of difference in the spatial configuration of the immunodominant region. The presence of ANCA in patients with autoimmune thyroid diseases without evidence of vasculitis might result from propylthiouracil-induced polyclonal activation.

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Purine nucleoside phosphorylase (PNP) catalyzes the reversible phosphorolysis of nucleosides and deoxynucleosides, generating ribose 1-phosphate and the purine base, which is an important step of purine catabolism pathway. The lack of such an activity in humans, owing to a genetic disorder, causes T-cell impairment, and thus drugs that inhibit human PNP activity have the potential of being utilized as modulators of the immunological system to treat leukemia, autoimmune diseases, and rejection in organ transplantation. Besides, the purine salvage pathway is the only possible way for apicomplexan parasites to obtain the building blocks for RNA and DNA synthesis, which makes PNP from these parasites an attractive target for drug development against diseases such as malaria. Hence, a number of research groups have made efforts to elucidate the mechanism of action of PNP based on structural and kinetic studies. It is conceivable that the mechanism may be different for PNPs from diverse sources, and influenced by the oligomeric state of the enzyme in solution. Furthermore, distinct transition state structures can make possible the rational design of specific inhibitors for human and apicomplexan enzymes. Here, we review the current status of these research efforts to elucidate the mechanism of PNP-catalyzed chemical reaction, focusing on the mammalian and Plamodium falciparum enzymes, targets for drug development against, respectively, T-Cell and Apicomplexan parasites-mediated diseases.

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The purpose of this study was to determine whether intracameral commercial lidocaine 2% induces alterations on the rabbit corneal endothelium. Forty white rabbits received different substances inside the anterior chamber: group (G)1, no substance; G2 and G3 received lidocaine 2% with preservative in aqueous solution; G4 and G5, lidocaine 2% with preservative in gel solution; G6 and G7, the anesthetic preservative (metilparahydroxybenzoate 0.1%); and G8 and G9, lidocaine 2% without preservative in aqueous solution. The animals from G2, 4, 6 and 8 were sacrificed after 1 h, and from G3, 5, 7 and 9 after 24 h after injection of the substance inside the anterior chamber. The corneas were clinically evaluated and assessed by transmission and scanning electron microscopy. G1, 2, 6, 7, 8 and 9 animals had very similar characteristics in clinical, ultrastructural and morphometric evaluations; the G3 and G4 animals showed discrete edema and one animal in G5 had intense corneal edema. We conclude that lidocaine 2% with preservative induces few ultrastructural alterations in the corneal endothelial cells.

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Endothelial cell function is essential to maintain corneal transparency, but unfortunately the regenerative capacity of the endothelium is limited. There are only a few reports describing the effect of age on morphologic appearance of corneal endothelial cells of dogs. Studies of normal corneal endothelial cells in humans and dogs have shown a decrease in endothelial cell density (ECD) and an increase in pleomorphism and polymegethism with advancing age. The purpose of this study was to investigate the effect of age on ECD and endothelial cell morphology in dogs. A total of 30 dogs were divided into three groups (10 dogs/group) based on age: group 1 (2-12 months old), group 2 (24-72 months old), and group 3 (84 months or older). Corneas were processed for light and scanning electron microscopy. Results showed only difference in cell density between group 1 and groups 2 and 3, showing an initial decrease in cell density as the animal matured. Whereas there was significantly greater variation in cell size within the dogs in group 3 than there was within the other two groups, suggesting that there was increased polymegethism and pleomorphism with advancing age.