977 resultados para template-assisted selective growth
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Abnormalities in any component of the cell cycle regulatory machine may result in oral. cancer, and markers of cell proliferation have been used to determine the prognosis of tumor progression. The aim of this study was to determine whether silver-stained nucleolar organizer region (AgNOR) and Ki-67 measurements could improve the assessment of growth rates in oral lesions. Eighty-three oral biopsies were studied, 20 of which were classified as fibrous inflammatory hyperplasia (FIH), 40 as leukoplakia (LKP) and 23 as oral. squamous cell carcinoma (OSCC). Within the LKP group, 22 out of 29 biopsies were diagnosed as non-dysplastic leukoplakia (LK) and 18 as dysplastic teukoptakia (DLK), presenting discrete, moderate and severe dysplasia. Ki-67 immunotabeting of the lesions increased steadily in the following order: FIH, DLK, LK and OSCC, indicating that Ki-67 is a good marker for predicting the protiferative fraction among benign, premalignant and malignant oral lesions. The median values of AgNOR parameters indicate that the morphometric index gives better results regarding the proliferative rate than the numerical one. A series of linear regressions between AgNOR parameters and Ki-67 showed positive associations. We conclude that a combination of Ki-67 and morphometric AgNOR analyses could be used as an aid in the determination of the protiferative status of oral epithelial. cells in oral cancer. (C) 2007 Elsevier GmbH. All rights reserved.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Nanocomposites created with polycarboxylic acid alone as a stabilization agent for prenucleation clusters-derived amorphous calcium phosphate exhibit nonperiodic apatite deposition. In the present study, we report the use of inorganic polyphosphate as a biomimetic analog of matrix phosphoprotein for directing poly(acrylic acid)-stabilized amorphous nano-precursor phases to assemble into periodic apatite-collagen nanocomposites. The sorption and desorption characteristics of sodium tripolyphosphate to type I collagen were examined. Periodic nanocomposite assembly with collagen as a template was demonstrated with TEM and SEM using a Portland cement-based resin composite and a phosphate-containing simulated body fluid. Apatite was detected within the collagen at 24 h and became more distinct at 48 h, with prenucleation clusters attaching to the collagen fibril surface during the initial infiltration stage. Apatite-collagen nanocomposites at 72 h were heavily mineralized with periodically arranged intrafibrillar apatite platelets. Defect-containing nanocomposites caused by desorption of TPP from collagen fibrils were observed in regions lacking the inorganic phase.
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Tin oxide (SnO) powders were obtained by the microwave-assisted hydrothermal synthesis technique using SnCl2 center dot 2H(2)O as a precursor. By changing the hydrothermal processing time, temperature, the type of mineralizing agent (NaOH, KOH or NH4 OH) and its concentration, SnO crystals having different sizes and morphologies could be achieved. The powders were characterized by X-ray diffraction (X-ray), Field Emission Scanning Electron Microscopy (FE-SEM), High Resolution Transmission Electron Microscopy (HR-TEM) and Selected Area Electron Diffraction (SAED). The results showed that plate-like form is the characteristic morphology of growth and the TEM analyses indicate the growth direction as (200). (c) 2007 Elsevier B.V. All rights reserved.
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The knowledge of cell-cycle control has shown that the capacity of malignant growth is acquired by the stepwise accumulation of defects in specific genes regulating cell growth. Histologic diagnosis might be improved by a quantitative evaluation of more specific diagnosis biomarkers, which could help to precisely identify pre-malignant and malignant oral lesions. The aim of the present study is to evaluate whether computer-based quantitative assessment of p53, PCNA and Ki-67 immunohistochemical expression, could be used clinically to foresee the risk of oral malignant transformation. This retrospective study was carried out in ninety-five oral biopsies, 27 were classified as fibrous inflammatory hyperplasia, 40 as leukoplakia and 28 as oral squamous cell carcinoma. Sixteen out of the 40 leukoplakia were diagnosed as non-dysplastic leukoplakia, the other 24 being dysplastic leukoplakia, of which 50.0% were classified as moderate to severe dysplasia. Comparison of the four groups of oral tissues showed significant rises in p53 and Ki-67 positivity index, which increased steadily in the order benign, pre-malignant, and malignant. In contrast, it was not possible to relate higher PCNA levels with pre-malignant and malignant oral lesions. We therefore conclude that PCNA immunohistochemistry expression is probably an inappropriate marker to identify oral carcinogenesis, whereas joint quantitative evaluation of p53 and Ki-67, appears to be useful as a tumor marker, providing a pre-diagnostic estimate of the potential for cell-cycle deregulation of the oral proliferate status.
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The eukaryotic translation initiation factor 5A (eIF5A) undergoes a specific post-translational modification called hypusination. This modification is required for the functionality of this protein. The compound N1-guanyl-1,7-diaminoheptane (GC7) is a potent and selective inhibitor of deoxyhypusine synthase, which catalyses the first step of eIF5A hypusination process. In the present study, the effects of GC7 on cell death were investigated using two cell lines: melan-a murine melanocytes and Tm5 marine melanoma. In vitro treatment with GC7 increased by 3-fold the number of cells presenting DNA fragmentation in Tm5 cells. Exposure to GC7 also decreased viability to both cell lines. This study also describes, for the first time, the in vivo antitumour effect of GC7, as indicated by impaired melanoma growth in C57BL/6 mice. Copyright © 2006 John Wiley & Sons, Ltd.
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The oil flotation isolation technique has been successfully applied to recover chaetothyrialean black yeasts and relatives from the environment. The selective mechanisms playing a role in isolation are unknown. The fungi concerned are supposed to occupy specialized microniches in nature, taking advantage of (1) oligotrophism. Mineral oil as a main selective agent may be based on (2) hydrophobicity or on (3) assimilation. All three hypotheses are tested in this paper. Results show that cell wall hydrophobicity is unlikely to be a selective factor. Incubation under poor nutrient conditions provides competitive advantage for black yeasts, especially for Exophiala strains, which are subsequently enriched by mineral oil which enhances growth in this group of fungi. Incubation under mineral media and mineral oil can be used as selective factor.
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Includes bibliography
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Aiming at improving the efficiency control of Phakopsora pachyrhizi, this research evaluated different application techniques, using spray deposits and yield parameters of soybean crop. Two experiments were carried out in the experimental area of FCA/UNESP - Botucatu, SP, Brazil, in the soybean crop, Conquista variety, in the 2006/2007 season. The first experiment was arranged in random blocks with eight treatments and four replications. The treatments were conducted in factorial arrangement 4×2 (four air levels 0, 9, 11 and 29 km/h combined at two nozzle angles 0 and 30°) using AXI 110015 nozzles. Ten plants on each plot were selected for sampling spray deposits. Artificial targets were fixed on plants, two in the top and another two in the bottom part of plants (abaxial and adaxial leaf surface each one). For deposit evaluations, a cupric tracer was used and the amount of deposits was determined by a spectrophotometer. The second experiment was carried out in the same place and the treatments were of the same arrangement as the previous experiment, including control treatment (untreated plants). The spraying with triazole fungicide was realized in R2 and R5.2 growth stages of soybean with 142 l/ha spray volume. The nozzle angled of 30° combined with maximum air speed promoted the highest spray deposits on the soybean crop and influenced positively the control of the soybean Asian rust as well in the productivity of this crop.
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Includes bibliography
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The aim of this study is to report the case of a quick growing brown tumour in the jaw after a parathyroidectomy due to the presence of a rare fifth parathyroid gland. The patient had chronic renal disease and the diagnosis was tertiary hyperparathyroidism. Thirty days after the parathyroidectomy, the patient returned with a significant increase in the tumour size. The suspicion of a supernumerary gland was confirmed by parathyroid scintigraphy. The treatment of brown tumour is dependent on the treatment of the hyperparathyroidism. However, curettage should be considered if a large lesion is disturbing mastication. In conclusion, this case should attract the attention of general practitioner dentists, since they may be the first professionals who have contact with the patient with a brown tumour in the jaws. Likewise, this case emphasises the importance of knowing the type of hyperparathyroidism involved to allow for effective treatment planning. © 2011 European Association for Cranio-Maxillo-Facial Surgery.
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Includes bibliography
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Includes bibliography
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Cystalline ceria (CeO2) nanoparticles have been synthesized by a simple and fast microwave-assisted hydrothermal (MAH) under NaOH, KOH, and NH4OH mineralizers added to a cerium ammonium nitrate aqueous solution. The products were characterized by X-ray powder diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), Fourier transformed-IR and Raman spectroscopies. Rietveld refinement reveals a cubic structure with a space group Fm3m while infrared data showed few traces of nitrates. Field emission scanning microcopy (FEG-SEM) revealed a homogeneous size distribution of nanometric CeO2 nanoparticles. The MAH process in KOH and NaOH showed most effective to dehydrate the adsorbed water and decrease the hydrogen bonding effect leaving a weakly agglomerated powder of hydrated ceria. TEM micrographs of CeO2 synthesized under MAH conditions reveal particles well-dispersed and homogeneously distributed. The MAH enabled cerium oxide to be synthesized at 100 °C for 8 min. © 2012 Elsevier B.V. All rights reserved.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)