Federal University of São Paulo

About: Federal University of São Paulo is a education organization based out in São Paulo, Brazil. It is known for research contribution in the topics: Population & Medicine. The organization has 27971 authors who have published 49365 publications receiving 935536 citations. The organization is also known as: Universidade Federal de São Paulo & Universidade Federal de Sao Paulo.

Subretinal implantation of retinal pigment epithelial cells derived from human embryonic stem cells: improved survival when implanted as a monolayer.

Abstract: PURPOSE To evaluate cell survival and tumorigenicity of human embryonic stem cell-derived retinal pigment epithelium (hESC-RPE) transplantation in immunocompromised nude rats. Cells were transplanted as a cell suspension (CS) or as a polarized monolayer plated on a parylene membrane (PM). METHODS Sixty-nine rats (38 male, 31 female) were surgically implanted with CS (n = 33) or PM (n = 36). Cohort subsets were killed at 1, 6, and 12 months after surgery. Both ocular tissues and systemic organs (brain, liver, kidneys, spleen, heart, and lungs) were fixed in 4% paraformaldehyde, embedded in paraffin, and sectioned. Every fifth section was stained with hematoxylin and eosin and analyzed histologically. Adjacent sections were processed for immunohistochemical analysis (as needed) using the following antibodies: anti-RPE65 (RPE-specific marker), anti-TRA-1-85 (human cell marker), anti-Ki67 (proliferation marker), anti-CD68 (macrophage), and anti-cytokeratin (epithelial marker). RESULTS The implanted cells were immunopositive for the RPE65 and TRA-1-85. Cell survival (P = 0.006) and the presence of a monolayer (P < 0.001) of hESC-RPE were significantly higher in eyes that received the PM. Gross morphological and histological analysis of the eye and the systemic organs after the surgery revealed no evidence of tumor or ectopic tissue formation in either group. CONCLUSIONS hESC-RPE can survive for at least 12 months in an immunocompromised animal model. Polarized monolayers of hESC-RPE show improved survival compared to cell suspensions. The lack of teratoma or any ectopic tissue formation in the implanted rats bodes well for similar results with respect to safety in human subjects.

Association of the length polymorphism in the human Per3 gene with the delayed sleep-phase syndrome: does latitude have an influence upon it?

Abstract: Study objectives The objective of this study is to analyze the influence of a previously reported hPer3 gene-length polymorphism in the delayed sleep-phase syndrome and in morningness-eveningness tendencies at low latitudes in the southern hemisphere. Design We have genotyped a length polymorphism in the hPer3 gene characterized by a short repeat allele (4-repeat) and a long repeat allele (5-repeat). Participants Seventeen patients with delayed sleep-phase syndrome; 156 volunteers chosen according to Horne-Ostberg questionnaire to have morning, intermediate, or evening preference; and 110 volunteers with no Horne-Ostberg score as a sample of the general population. Results We have found a higher frequency of 5-repeat allele in the delayed sleep-phase syndrome group and an association of this polymorphism with diurnal preference. Conclusion Our results suggest that latitude has a role in the influence of hPer3 gene polymorphism on delayed sleep-phase syndrome and confirm previous data showing its association with morningness-eveningness tendencies.

Proteomic Analysis of Trypanosoma cruzi Secretome: Characterization of Two Populations of Extracellular Vesicles and Soluble Proteins

Abstract: Microorganisms use specialized systems to export virulence factors into host cells. Secretion of effector proteins into the extracellular environment has been described in Trypanosoma cruzi; however, a comprehensive proteomic analysis of the secretome and the secretion mechanisms involved remain elusive. Here, we present evidence that T. cruzi releases proteins associated with vesicles that are formed by at least two different mechanisms. Transmission electron microscopy showed larger vesicles budding from the plasma membrane of noninfective epimastigotes and infective metacyclic trypomastigotes, as well as smaller vesicles within the flagellar pocket of both forms. Parasite conditioned culture supernatant was fractionated and characterized by morphological, immunochemical, and proteomic analyses. Three fractions were obtained by differential ultracentrifugation: the first enriched in larger vesicles resembling ectosomes, the second enriched in smaller vesicles resembling exosomes, and a third fraction en...

Heparan sulfate and heparin interactions with proteins

Abstract: Heparan sulfate (HS) polysaccharides are ubiquitous components of the cell surface and extracellular matrix of all multicellular animals, whereas heparin is present within mast cells and can be vie...