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Porto Alegre, Brazil

Foroni L.,University of Bologna | Dirani G.,Clinical Pathology Division | Gualandi C.,University of Bologna | Focarete M.L.,University of Bologna | Pasquinelli G.,Clinical Pathology Division
Tissue Engineering - Part C: Methods | Year: 2010

Morphological and immunophenotypic characterization of cells grown on poly(l-lactic acid) (PLLA) electrospun scaffolds is usually performed using immunofluorescence and cryosections. However, these methods present practical limits; histological processing, on the other hand, is believed to lead to artifactual changes in the scaffold structure. Here the formalin-fixed paraffin-embedding (FFPE) procedure was tailored to process PLLA electrospun scaffolds grown with human umbilical vein endothelial cells. After 1 to 7 days of culture, the scaffolds were processed with the FFPE procedure. Using this protocol, not only cross sections but also "en face" sections were obtained. This made possible to perform the effective light microscopy analysis of cell morphology and to assess cell adhesion and penetration without considerable scaffold damage. The method was also suitable for immunohistochemical assays, such as proliferation (Ki67), extracellular matrix production (type IV collagen), survival (cleaved caspase-3), and immunophenotyping (KDR, CD44, vimentin, CD45); results were compared with those obtained using complementary techniques (scanning electron microscopy, Alamar Blue assay, and cryosections). The FFPE protocol can be safely applied to PLLA scaffolds and provides information that are essential to study the mechanisms of interaction between cells and PLLA fibers before their potential implantation in vivo. © 2010 Mary Ann Liebert, Inc. Source


Cavagnolli G.,Federal University of Rio Grande do Sul | Comerlato J.,Clinical Pathology Division | Comerlato C.,Clinical Pathology Division | Renz P.B.,Clinical Pathology Division | And 2 more authors.
Diabetic Medicine | Year: 2011

Aim To analyse the performance of HbA1c in diagnosing Type 2 diabetes based on fasting plasma glucose and/or 2-h plasma glucose measurements after a 75-g oral glucose tolerance test.Methods This is a study of diagnostic test accuracy in individuals referred to the Clinical Pathology Department for oral glucose tolerance testing. After fasting overnight, HbA1c, fasting plasma glucose and 2-h plasma glucose were measured. The receiver operating characteristic curve was used to evaluate the diagnostic performance of HbA1c.Results Four hundred and ninety-eight subjects (195 male, mean age 56 years) were enrolled and 115 (23.1%) were diagnosed with diabetes according to glucose-based methods and only 56 (11.2%) individuals were identified by HbA1c≥ 6.5% (48 mmol/mol) (sensitivity 20.9%, specificity 95.3%). There is poor agreement between the newly recommended criterion and the current glucose-based diagnostic criteria (κ = 0.217; P < 0.001), probably because the diagnostic methods identify different populations of patients. Adding a glucose-based method into an algorithm, as proposed by the UK Department of Health, improved HbA1c performance.Conclusions HbA1c≥ 6.5% (48 mmol/mol) showed limited sensitivity to diabetes diagnosis, although with high specificity. The results suggest that this cut-off point would not be enough to diagnose diabetes. Its use as the sole diabetes diagnostic test should be interpreted with caution to assure the correct classification of diabetic individuals. © 2010 The Authors. Diabetic Medicine © 2010 Diabetes UK. Source

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