Simple mucin-type carbohydrate antigens (T, sialosyl T, Tn and sialosyl-Tn) in breast carcinogenesis

Immunohistochemical analysis of the expression of simple mucin-type carbohydrate antigens (Tn, sialyl-Tn and T) was performed in a series of 43 cases of intraductal hyperplasia without atypia, 9 cases of intraductal hyperplasia with atypia, 54 cases of ductal carcinoma in situ (DCIS) and 26 cases of invasive breast carcinoma. We also studied 36 cases of isolated breast normal epithelium, 20 cases of 'normal' breast epithelium adjacent to neoplasms and 14 cases of apocrine metaplasia. All antigens were detected in different frequencies in normal, hyperplastic, metaplastic and neoplastic breast epithelium. Tn and sialyl-Tn are expressed more frequently in malignant than in benign breast epithelium; while Tn expression increases from normal to invasive carcinomas, sialyl-Tn increases until DCIS and drops in invasive carcinomas, suggesting that either there is a failure of a proportion of DCIS to progress to invasive carcinoma or loss of expression of sialyl-Tn when some carcinomas become invasive. The high frequency of Tn and sialyl-Tn expression in breast intraductal proliferations probably reflects incomplete glycosylation in these lesions, which is a well-known tumour-associated phenomenon and supports the assumption that such lesions are putative precursors of breast cancer. T antigen was expressed in all groups studied, but its prevalence differed significantly between normal and neoplastic epithelium. The expression of these antigens in epithelium adjacent to carcinomas is similar to that found in isolated normal breast epithelium, whereas apocrine metaplasia has a pattern of simple mucin-type glycosylation that is specific and distinct from that of the normal breast epithelium, with a high frequency of marked expression of Tn and sialyl-Tn. The similarity of the pattern of expression of simple mucin-type antigens in metaplasia and malignant neoplasia reduces the usefulness of these markers from a diagnostic standpoint.

Obtenção de mutantes de Bacillus thuringiensis por inserção do transposon Tn-5 e avaliação da toxicidade frente a larvas de Spodoptera frugiperda

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

Obtenção da liga Ti-35Nb por metalurgia do pó para utilização em próteses ortopédicas

Pós-graduação em Engenharia Mecânica - FEG

Comparação dos efeitos de compressão isostática e compressão uniaxial na obtenção da liga NiTi por metalurgia do pó

Several alloys present the shape memory effect and among them, the equiatomic NiTi alloy, nitinol, is the most important one. It is usually used in several engineering applications and also in biomedical devices, in the fabrication of orthodontic wire, stents and Judet staples. Although a considerable amount of these biomedical devices is utilized in Brazil and a fraction of it is already made here, all nitinol used is bought abroad. Thus, it is important to develop the necessary know-how to fabricate NiTi wire and sheet. It would mean less importation with job creation and wealth generation for the country. In this work nitinol was obtained powder metallurgy from elemental powders of Ti and Ni using uniaxial compression and uniaxial compression followed by isostatic compression. The final densities achieved were determined by the Archimedes method. The precipitation of intermetallic secondary phases was studied and the samples were characterized by metallographic analysis, optical microscopy and X-ray diffraction. Results indicated that 50 hours sintering route showed a low amount of intermetallics, and no trace of unreacted powder. XRD and metallography at room temperature indicated B19’ as the predominant phase, which corresponds to martensite. Although density results showed little dispersion, the most dense sample was compacted under uniaxial compression and presented 4.8 g/cm3, corresponding to 20.84% porosity. Density variation was considered normal to the measurement process and independent of the compaction mode

Estudo de tempos e temperaturas de sinterização na obtenção da liga NiTi por metalurgia do pó

The nickel-titanium alloys are very attractive and so it is widely used in industry, engineering applications in general and also in biomedical and dental applications. Besides showing the shape of memory effect, biocompatibility and superelastic, the alloy commercially known as Nitinol, has excellent mechanical properties. Most devices used in Brazil have been produced nationally, but using imported material is also necessary, which shows the need of produce the alloy nationally. In this study we have investigated the influence of sintering temperatures and times to obtain nickel-titanium alloys by powder metallurgy alloys and the characterization of the precipitated intermetallic phases by using the post-mix of elemental nickel and titanium in proportion of 49.5% Ti - 50.5% Ni. The samples were sintered at 930ºC for periods of 30, 40 and 50 hours and were characterized by optical microscopy using metallography and x-ray diffraction. The results of the study show that the 50 hours sintering time was the most suitable time for obtaining the alloy, observing a low volume of precipitated intermetallic phases and absence of Ni and Ti residuals