Evolutionary Changes in the Complexity of the Tectum of Nontetrapods: A Cladistic Approach

Background: The tectum is a structure localized in the roof of the midbrain in vertebrates, and is taken to be highly conserved in evolution. The present article assessed three hypotheses concerning the evolution of lamination and citoarchitecture of the tectum of nontetrapod animals: 1) There is a significant degree of phylogenetic inertia in both traits studied (number of cellular layers and number of cell classes in tectum); 2) Both traits are positively correlated accross evolution after correction for phylogeny; and 3) Different developmental pathways should generate different patterns of lamination and cytoarchitecture. Methodology/Principal Findings: The hypotheses were tested using analytical-computational tools for phylogenetic hypothesis testing. Both traits presented a considerably large phylogenetic signal and were positively associated. However, no difference was found between two clades classified as per the general developmental pathways of their brains. Conclusions/Significance: The evidence amassed points to more variation in the tectum than would be expected by phylogeny in three species from the taxa analysed; this variation is not better explained by differences in the main course of development, as would be predicted by the developmental clade hypothesis. Those findings shed new light on th

Histological study on sinus lift grafting by Fisiograft and Bio-Oss

The work aims to provide a histological investigation of Fisiograft(R) a PLA/PGA copolymer, used as filler for bone defects in humans. The study was performed on biopsies of sinus lifts where Bio-Oss(R) and Fisiograft(R) gel were applied as graft material. Bone regeneration was satisfactory in all sinus lifts, even when Fisiograft(R) was applied alone. Due to remarkable osteoclast activity, Bio-Oss(R) granules were cleared from the majority of biopsy cores. At histology, Fisiograft(R) gel appeared as globes enveloped by fibroblasts, displaying an epithelial-like cell appearance. Due to its solubility in solvents, undegraded Fisiograft(R) (recorded for 7 months or more) did not stain whereas degraded Fisiograft(R) stained positive. The loose connective tissue, that surrounded Fisiograft(R), and bone contained isolated mastocytes. Bone grew inside the loose connective and often reached the surface of Fisiograft(R) by intervening cells. The results seem to indicate that Fisiograft(R) may be considered both a polymer useful for fastening bone substitutes inside a defect and in addition a material capable of prompting bone regeneration, with or without the use of a bone substitute. In addition to space-former and space-maintainer functions, Fisiograft(R) shows potential bone stimulation function, which may be labelled as osteopromotive capability

Viability of autogenous bone grafts obtained by using bone collectors: histological and microbiological study Viabilidade dos enxertos autógenos obtidos com a utilização de coletores para osso: estudo histológico e microbiológico

The use of autogenous bone grafts is considered to be the best choice for reconstructive surgery. In the periodontal literature, the utilization of osseous coagulum was suggested by the end of the sixties. The purpose of this study is to consider the use of bone collectors (bone traps) as an alternative method for obtaining material to fill small bone imperfections, such as fenestrations and dehiscences. Thirty samples were obtained from bone drilling during fixture installation in patients (13 men and 17 women, with an average age of 54 years) requiring treatment at the Department of Periodontology and Implant Dentistry, University of Santo Amaro. These samples were fixed in 10% neutral formaldehyde for 24 hours and subjected to histological preparation, in order to evaluate the presence of viable osteoblasts. In addition, the material was placed in a fluid thioglycolate medium and incubated for 24 hours at 36 ± 1°C in aerobiosis and anaerobiosis. Bacterial growth evaluation was made by using six different culture media (MacConkey agar, blood agar base, mannitol salt agar, Anaerokit LTD medium, Anaerokit LTD - bile medium, Anaerinsol). The results show that, if proper care is taken to prevent saliva contamination during the surgical procedure, this method of collecting autogenous bone may be useful in situations where small amounts of bone are required.<br>A utilização de enxertos autógenos é considerada a melhor opção nos tratamentos cirúrgicos de reconstrução óssea. Na literatura periodontal, a utilização de coágulo ósseo foi sugerida no final da década de 60. O objetivo deste estudo é considerar a utilização de coletores para osso como um método alternativo de se obter osso autógeno para preenchimento de defeitos ósseos como fenestrações e deiscências. Trinta amostras foram obtidas no processo de perfuração do tecido ósseo, durante a instalação de implantes em pacientes (13 homens e 17 mulheres, com média etária de 54 anos) que foram submetidos a tratamento na Disciplina de Periodontia e Implantodontia da Universidade de Santo Amaro. Essas amostras foram fixadas em solução de formol neutro a 10% por 24 horas para serem analisadas histologicamente com o intuito de avaliar a presença de osteoblastos viáveis. Além das amostras fixadas, também foram obtidos espécimens que foram incubados em aerobiose e em anaerobiose, em meio de tioglicolato por 24 h a 36 ± 1°C. A avaliação do crescimento bacteriano foi feita através de seis meios seletivos de cultura (ágar MacConkey, ágar-sangue, ágar manitol, meio Anaerokit LTD, meio Anaerokit LTD - bile e Anaerinsol). Os resultados mostraram que, se forem tomados certos cuidados para prevenir a contaminação com saliva durante o procedimento cirúrgico, este método de coletar osso autógeno pode ser útil em situações em que pequenas quantidades de osso são necessárias