Histological evaluation of latissimus dorsi muscle subjected to tissue expansion after infiltration with botulinum toxin: an experimental study in rats

The authors describe histological changes in the latissimus dorsi muscle submitted to expansion after relaxation with botulinum toxin. The possible practical benefits include increased muscle compliance and better accommodation of a prosthesis. The experimental model involved 10 Wistar rats (Rattus norvegicus) of the same age, with average weight of 300 g. Muscle biopsies before and after expansion were performed in normal muscle, in a control group (with expanders alone), and in a group with expanders and botulinum toxin. Expanders measuring 3 cm3 were positioned below the muscle and expanded with 0.3 ml of saline weekly, for 10 weeks. Histological sections were stained using hematoxylin-eosin for general evaluation and Masson's trichrome for evaluation of connective tissue. The muscle fibers submitted to expansion under the action of botulinum toxin showed less fibrosis and less intense proliferation of blood vessels than in the group without botulinum toxin, and the atrophy and reduction in the number of muscle fibers were less prominent than in the group that did not receive botulinum toxin. The findings suggest that muscle expansion associated with botulinum toxin relaxation preserves skeletal muscle characteristics by providing better accommodation and protection for a prosthesis and facilitating expansion dynamics; this method may also reduce pain

Unraveling Amazon tree community assembly using Maximum Information Entropy: a quantitative analysis of tropical forest ecology

In a time of rapid global change, the question of what determines patterns in species abundance distribution remains a priority for understanding the complex dynamics of ecosystems. The constrained maximization of information entropy provides a framework for the understanding of such complex systems dynamics by a quantitative analysis of important constraints via predictions using least biased probability distributions. We apply it to over two thousand hectares of Amazonian tree inventories across seven forest types and thirteen functional traits, representing major global axes of plant strategies. Results show that constraints formed by regional relative abundances of genera explain eight times more of local relative abundances than constraints based on directional selection for specific functional traits, although the latter does show clear signals of environmental dependency. These results provide a quantitative insight by inference from large-scale data using cross-disciplinary methods, furthering our understanding of ecological dynamics

Rarity of monodominance in hyperdiverse Amazonian forests.

Tropical forests are known for their high diversity. Yet, forest patches do occur in the tropics where a single tree species is dominant. Such "monodominant" forests are known from all of the main tropical regions. For Amazonia, we sampled the occurrence of monodominance in a massive, basin-wide database of forest-inventory plots from the Amazon Tree Diversity Network (ATDN). Utilizing a simple defining metric of at least half of the trees ≥ 10 cm diameter belonging to one species, we found only a few occurrences of monodominance in Amazonia, and the phenomenon was not significantly linked to previously hypothesized life history traits such wood density, seed mass, ectomycorrhizal associations, or Rhizobium nodulation. In our analysis, coppicing (the formation of sprouts at the base of the tree or on roots) was the only trait significantly linked to monodominance. While at specific locales coppicing or ectomycorrhizal associations may confer a considerable advantage to a tree species and lead to its monodominance, very few species have these traits. Mining of the ATDN dataset suggests that monodominance is quite rare in Amazonia, and may be linked primarily to edaphic factors

Unraveling Amazon tree community assembly using Maximum Information Entropy: a quantitative analysis of tropical forest ecology

In a time of rapid global change, the question of what determines patterns in species abundance distribution remains a priority for understanding the complex dynamics of ecosystems. The constrained maximization of information entropy provides a framework for the understanding of such complex systems dynamics by a quantitative analysis of important constraints via predictions using least biased probability distributions. We apply it to over two thousand hectares of Amazonian tree inventories across seven forest types and thirteen functional traits, representing major global axes of plant strategies. Results show that constraints formed by regional relative abundances of genera explain eight times more of local relative abundances than constraints based on directional selection for specific functional traits, although the latter does show clear signals of environmental dependency. These results provide a quantitative insight by inference from large-scale data using cross-disciplinary methods, furthering our understanding of ecological dynamics

Avaliação da radiopacidade de diferentes sistemas cerâmicos livres de metal

The aim of this study to evaluate the radiopacity of metal-free ceramic restorations in an objective, subjective and by SEM and EDS. Ceramics were used: Noritake EX-3 (Noritake), VM13 (Vita), IPS Empress II (Ivoclar Vivadent), IPS e.max ZirPress (Ivoclar Vivadent) and PM9 (Vita). For the objective evaluation were prepared five specimens with thickness of 1, 2, 3 and 4 mm, which were radiographed with a aluminum step and a dental section, using direct digital system. The radiographic images were submitted to the reading of optical density. For subjective evaluation were fabricated phantoms, simulating the back of the dental arches, in which two teeth of each phantom received an inlay preparation, were restored with the studied ceramics, and were x-rayed by the interproximal technique. These radiographs were evaluated by three groups of examiners, dentists, radiologists, and prosthetists. To analyze the chemical elements that provide radiopacity characteristics of the materials, evaluation was performed by SEM and EDS. The results of objective evaluation indicated significant differences between the radiopacity of the studied ceramics. For 1 and 2 mm in thickness and the ceramics were all higher radiopacity dentin and enamel below. Ceramics Noritake EX3 showed higher radiopacity in all thicknesses. There was evident on the evaluations simulating clinical conditions, the differences observed in the radiopacity of objective evaluation. The group of dentists had a lower diagnostic accuracy when compared to groups of specialists, and radiologists had the highest diagnostic accuracy for ceramics (0.57). Independent group of evaluators was not possible to distinguish between X-ray and metal-free ceramic composites. The result of evaluation of materials by SEM and EDS indicated as possible elements radiopacifiers barium to ceramic Noritake EX-3 (2.19%), VM13 (1.04%), PM9 (0.70%) and IPS Empress II (0.70%) and zinc (4.50%) and cerium (1.45%) for the ceramic IPS E.max ZirPress.No presente estudo avaliou-se a radiopacidade de restaurações cerâmicas livres de metal de forma objetiva, subjetiva e por meio de MEV/EDS. Foram utilizadas as cerâmicas: Noritake EX-3 (Noritake), VM13 (Vita), IPS Empress II (Ivoclar Vivadent), IPS E.max ZirPress (Ivoclar Vivadent) e PM9 (Vita). Para a avaliação objetiva foram confeccionados cinco corpos de prova nas espessuras de 1, 2, 3 e 4 mm, que foram radiografados juntamente com uma escala de densidade e uma secção dental, utilizando-se sistema digital direto. As imagens radiográficas foram submetidas à leitura de densidade óptica. Para a avaliação subjetiva foram confeccionados phantoms, simulando a parte posterior das arcadas dentárias, no qual dois dentes de cada phantom foram submetidos a preparos inlay, restaurados com as cerâmicas estudadas, e radiografados pela técnica interproximal. Essas radiografias foram avaliadas por três grupos de examinadores: cirurgiões-dentistas, radiologistas e protesistas. Para a análise dos elementos químicos que dão características de radiopacidade aos materiais, foi realizada avaliação pelo MEV/EDS. Os resultados da avaliação objetiva indicaram diferenças significativas entre as radiopacidades das cerâmicas estudadas. Para 1 e 2 mm de espessuras todas as cerâmicas apresentaram radiopacidade superior a da dentina e inferior a do esmalte. A cerâmica Noritake EX3 apresentou maior radiopacidade em todas as espessuras. Não se puderam constatar, nas avaliações simulando condições clínicas, as diferenças de radiopacidades observadas na avaliação objetiva. O grupo dos cirurgiões-dentistas apresentou a menor acurácia diagnóstica quando comparados aos grupos de especialistas, sendo que os radiologistas apresentaram a maior acurácia diagnóstica para cerâmica (0,57). Independente do grupo de avaliadores, não foi possível a distinção radiográfica entre cerâmicas livre de metal e compósitos. O resultado da avaliação dos materiais pelo MEV/EDS indicou como possíveis elementos radiopacificadores: bário para as cerâmicas Noritake EX-3 (2,19%), VM13 (1,04%), PM9 (0,70%) e IPS Empress II (0,70%); e zinco (4,50%) e cério (1,45%) para a cerâmica IPS E.max ZirPress

[RETRACTED ARTICLE] Gastric and jejunal histopathological changes in patients undergoing bariatric surgery

ABSTRACT BACKGROUND Morbid obesity is a multifactorial disease that is increasingly treated by surgery. OBJECTIVE To evaluate gastric histopathological changes in obese, and to compare with patients who underwent gastrojejunal bypass and the jejunal mucosa after the surgery. METHODS This is an observational study performed at a tertiary public hospital, evaluating endoscopic biopsies from 36 preoperative patients and 35 postoperative. RESULTS In the preoperative group, 80.6% had chronic gastritis, which was active in 38.9% (77.1% and 20.1%, respectively, in the postoperative). The postoperative group had a significant reduction in Helicobacter pylori infection (P=0.0001). A longer length of the gastric stump and a time since surgery of more than two years were associated with Helicobacter pylori infection. The jejunal mucosa was normal in 91.4% and showed slight nonspecific chronic inflammation in 8.6%. CONCLUSION There was a reduction in the incidence of Helicobacter pylori infection in the postoperative group. A longer length of the gastric stump and longer time elapsed since surgery were associated with Helicobacter pylori infection. The jejunal mucosa was considered normal in an absolute majority of patients

GASTRIC AND JEJUNAL HISTOPATHOLOGICAL CHANGES IN PATIENTS UNDERGOING BARIATRIC SURGERY

ABSTRACT Background: Morbid obesity is a multifactorial disease that increasingly is being treated by surgery. Aim: To evaluate gastric histopathological changes in obese, and to compare with patients who underwent gastrojejunal bypass and the jejunal mucosa after the surgery. Methods: This is an observational study performed at a tertiary public hospital, evaluating endoscopic biopsies from 36 preoperative patients and 35 postoperative. Results: In the preoperative group, 80.6% had chronic gastritis, which was active in 38.9% (77.1% and 20.1%, respectively, in the postoperative). The postoperative group had a significant reduction in H. pylori infection (p=0.0001). A longer length of the gastric stump and a time since surgery of more than two years were associated with Helicobacter pylori infection. The jejunal mucosa was normal in 91.4% and showed slight nonspecific chronic inflammation in 8.6%. Conclusion: There was a reduction in the incidence of Helicobacter pylori infection in the postoperative group. A longer length of the gastric stump and longer time elapsed since surgery were associated with Helicobacter pylori infection. The jejunal mucosa was considered normal in an absolute majority of patients