RESUMO
The lack of information on structural basis where proteins are involved, as well as the biomineralization processes of different systems such as bones, diatom frustules, and eggshells, have intrigued scientists from different fields for decades. This scientific curiosity has led to the use of methodologies that help understand the mechanism involved in the formation of these complex structures. Therefore, this work focuses on the use of eggshell membranes from different species of ratites (emu and ostrich) and reptiles (two species of crocodiles) as a model to differentiate biocalcification and biosilicification by introducing calcium phosphate or silica inside the membrane fiber mantles. We performed this to obtain information about the process of eggshell formation as well as the changes that occur in the membrane during crystal formation. In order to identify and understand the early processes leading to the formation of the microstructures present in the eggshell, we decided to carry out the synthesis of silica-carbonate of calcium, barium, and strontium called biomorph in the presence of intramineral proteins. This was carried out to evaluate the influence of these proteins on the formation of specific structures. We found that the proteins on untreated membranes, present a structural growth similar to those observed in the inner part of the eggshell, while in treated membranes, the structures formed present a high similarity with those observed in the outer and intermediate part of the eggshell. Finally, a topographic and molecular analysis of the biomorphs and membranes was performed by scanning electron microscopy (SEM), Raman and Fourier-transform Infrared (FTIR) spectroscopies.
RESUMO
BACKGROUND: Epidemiological studies suggest an association between periodontal disease and coronary heart disease. It is possible that periodontal disease may contribute to plaque destabilization in patients with acute coronary syndrome. AIM: To assess the association between severity of periodontal disease, the number of acute plaques and extension of coronary artery disease in patients with acute coronary syndrome. PATIENTS AND METHODS: The severity of periodontal disease was assessed by skilled independent observers in patients with acute coronary syndrome subjected to coronary angiography. The periodental disease was classified as mild or severe. Acute plaques were defined on angiography as those with thrombi, ulcers or flow alterations. The extension of coronary disease was analyzed using the Sullivan score. RESULTS: Forty three patients (35 males) aged 41 to 83 years, were studied. Mild and severe periodontal disease was present in 18 (42%) and 25 (58%) patients respectively. Seventy six percent of those with severe disease had two or more acute plaques, compared with 17% of those with mild disease (p<0.001). Median Sullivan score was 80.6 and 57.2 in patients with severe or mild periodontal disease respectively (p=0.001). CONCLUSIONS: Severe periodontal disease was associated with a higher number of acute coronary plasques and a higher extension of coronary artery disease, in patients with acute coronary syndromes.