1,720,975 research outputs found
Role of HER2 in esophageal and gastric carcinogenesis and reliability of its evaluation in endoscopic biopsies
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One protocol to rule them all: a pilot study to identify the best fixation and decalcification approach for bone marrow biopsy immunohistochemistry
No full textObjective. Standardization of the pre-analytical phases of bone marrow trephine biopsy (BM) has yet to be achieved. In particular, several fixative and decalcifying reagents with specific benefits and drawbacks are described, but only a few direct comparisons are available. This study aims to test the most used fixation and decalcification protocols and evaluate their effect on tissue antigenicity via immunohistochemistry (IHC). Methods. To avoid damaging and exhausting diagnostic BMs, we used “surrogate” BMs obtained from dedicated grossing of a non-pathologic spleen. Eleven fixation and decalcification protocols were tested, and their performances were evaluated via IHC protein expression of 25 biomarkers. Results. The IHC yield varied based on the fixative and decalcifying reagents, but the overall quality is mainly related to the fixative rather than the decalcifying phases. The protocol with the lowest number of inadequate IHC stains (5 out of 25) combined commercially available B5-based fixative and EDTA-based decalcifying reagents. The worst metrics (8 inadequate IHC stains out of 25) were obtained with a protocol based on “in-house” B5-based and EDTA-based reagents. Conclusions. We compared different protocols and found the best combination of fixative and decalcifying reagents for accurate IHC staining. These findings can improve bone marrow sample handling and standardization in pathology laboratories
Factors affecting immunoreactivity in long-term storage of formalin-fixed paraffin-embedded tissue sections
No full textAntigen decay in archival formalin-fixed paraffin-embedded (FFPE) tissue sections for immunohistochemistry is a well-known phenomenon which may have repercussions on translational and research studies and length of storage time appears fundamental. The aim of this study was to evaluate all possible factors which may lead to antigen decay on a prospective standardized collection of human tissues with a panel of 14 routinely used antibodies. Serial slide sections from FFPE control tissues were stored using different methods (routine storage at room temperature, Parafilm(®) protected, paraffin coated and cold stored at 4 °C) and for different time periods: 1, 6, 9, 12, 24 and 36 months. Immunohistochemistry was performed at each time cutoff simultaneously on stored sections and on freshly cut sections using a panel of 14 antibodies. Immunoreactivity was compared with immunoreactions performed at time zero. Reduction in immunostaining was observed for a subset of antibodies (CD3, CD 31, CD117, estrogen and progesterone receptors, Ki67, p53, TTF-1, vimentin) while for others (smooth muscle actin, keratins 7, 20, AE1/AE3, 34βE12), no antigen decay was observed. Loss of antigenicity was proportional to tissue section age and was dependent on mode of storage with cold storage slides being the least affected. All antigens with reductions in immunosignal were nuclear or membranous, and they all required heat pre-treatment for antigen retrieval. In contrast to results from other studies, when pre-analytical factors are strictly controlled and standardized, antigen decay seems to be restricted to nuclear or membrane antigens which require heat antigen retrieval
Be bold, start cold! cold formalin fixation of colorectal cancer specimens granted superior DNA and RNA quality for downstream molecular analysis
No full textThe use of cold formalin fixation (CFF; i.e., fixating tissue samples with 4 °C precooled formalin) recently attracted further attention owing to its putative improved ability to preserve nucleic acid compared with standard room temperature formalin (SFF). In this study, we aimed to assess the effect of four formalin-based fixation protocols (SFF, CFF, delayed formalin fixation-DFF, and cold formalin hyperfixation; CFH) on both DNA and RNA quality. We collected 97 colorectal cancer (CRC) and analyzed 23 metrics of nucleic acid quantity and quality yield using a multiplatform approach by combining spectrophotometric, fluorimetric, electrophoretic, and polymerase chain reaction (PCR) assays. Following confirmation of fixation-protocol-related different effects via clustering analysis, CFF presented best metrics compared with all protocols, specifically positive coefficients of DV1000-60000, DV2/DV1, DNA λ ratio 260/230, and ABL gene expression absolute copies, and negative coefficient of DV150-1000. The SFF subgroup presented a positive coefficient of DV150-1000 and negative coefficients for DV1000-60000, DV2/DV1, RNA λ ratio 260/230, RNA QuBit concentration, DV100/200, RNA electrophoresis concentration and absolute quantity, and ABL copies. Overall, we confirmed the superior yield performances of CFF preservation for both DNA and RNA compared with the other protocols in our series of CRC samples. Pending further validations and clarification of the specific mechanisms behind these findings, our study supports the implementation of CFF in the pathology unit routine specimen management for tumor tissue molecular profiling
Twenty years of gastroenteropancreatic neuroendocrine tumors: is reclassification worthwhile and feasible?
No full textGastroenteropancreatic (GEP) neuroendocrine tumors (NETs) are rare neoplasms with heterogeneous clinical behavior and potential long-term survival. In 2006/2007, the European Neuroendocrine Tumors Society introduced an important parameter, grade (based on mitoses and Ki-67 proliferation rate), which became part of the latest 2010-WHO classification. Since this is an important tool in the choice of therapeutic algorithm of patients with NETs, our aim was to audit whether retrospective reclassification is possible and feasible and correlate pathological findings with survival. From the histopathology archive, 338 GEP-NETs (1994-2014) were identified, of which 250 were diagnosed pre-2010 and 80 of these have needed, up till now, classification (morphology and grade-mitotic count/Ki-67). Morphology was well differentiated (WD) in 74 cases while only 6 cases were poorly differentiated (PD). Grade was reclassified: G1-45 cases (56 %); G2-28 cases (35 %); G3-7 cases (9 %). Overall survival (OS) in WD NETs was strikingly better compared to PD neoplasms. Differences in OS between grade were statistically significant (p < 0.0001) and, in particular, grade identified a subgroup of patients with WD lesions but with less favorable clinical behavior (OS at 5 years: G1-89 %; G2-48 %; G3-0 %; G1 vs G2 p = 0.03). Feasibility analysis quantified time for reclassification to be between 45 and 64 min/case. Our series confirms the importance of grade in prognostic stratification and underlines that reclassification is feasible, and may prove worthwhile in patient management, especially in view of the potential long survival of patients with NETs and risk of use of inappropriate therapies
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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