46 research outputs found

    Local and systemic immunomodulatory mechanisms triggered by Human Papillomavirus transformed cells: a potential role for G-CSF and neutrophils

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    Cervical cancer is the last stage of a series of molecular and cellular alterations initiated with Human Papillomavirus (HPV) infection. The process involves immune responses and evasion mechanisms, which culminates with tolerance toward tumor antigens. Our objective was to understand local and systemic changes in the interactions between HPV associated cervical lesions and the immune system as lesions progress to cancer. Locally, we observed higher cervical leukocyte infiltrate, reflected by the increase in the frequency of T lymphocytes, neutrophils and M2 macrophages, in cancer patients. We observed a strong negative correlation between the frequency of neutrophils and T cells in precursor and cancer samples, but not cervicitis. In 3D tumor cell cultures, neutrophils inhibited T cell activity, displayed longer viability and longer CD16 expression half-life than neat neutrophil cultures. Systemically, we observed higher plasma G-CSF concentration, higher frequency of immature low density neutrophils, and tolerogenic monocyte derived dendritic cells, MoDCs, also in cancer patients. Interestingly, there was a negative correlation between T cell activation by MoDCs and G-CSF concentration in the plasma. Our results indicate that neutrophils and G-CSF may be part of the immune escape mechanisms triggered by cervical cancer cells, locally and systemically, respectively.Tis study was supported by Sao Paulo Research foundation: grants 2008/57889-1, 2010/20010-4, 2014/19326-6, by the Brazilian National Counsel of Technological and Scientifc Development: grant 573799/2008-3. KLFA and RAMR had PhD fellowships by Sao Paulo Research Foundation, CRSF has a Coordination for the Improvement of Higher Education Personnel PhD fellowship. We thank the Pathology Department of the School of Medicine, coordinated by Prof. VenĂąncio Avancini Ferreira Alves, Universidade de SĂŁo Paulo for the slides containing histological samples from the biopsies used in this study. We thank Sandra Alexandre Alves for her technical support.info:eu-repo/semantics/publishedVersio

    Quantitative-spatial assessment of soil contamination in S. Francisco de Assis due to mining activity of the Panasqueira mine (Portugal)

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    Through the years, mining and beneficiation processes produces large amounts of As-rich mine wastes laid up in huge tailings and open-air impoundments (Barroca Grande and Rio tailings) that are the main source of pollution in the surrounding area once they are exposed to the weathering conditions leading to the formation of AMD and consequently to the contamination of the surrounding environments, in particularly soils. In order to investigate the environmental contamination impact on S. Francisco de Assis (village located between the two major impoundments and tailings) agricultural soils, a geochemical survey was undertaken to assess toxic metals associations, related levels and their spatial distribution, and to identify the possible contamination sources. According to the calculated contamination factor, As and Zn have a very high contamination factor giving rise to 65.4 % of samples with a moderate to high pollution degree; 34.6 % have been classified as nil to very low pollution degree. The contamination factor spatial distribution put in evidence the fact that As, Cd, Cu, Pb, and Zn soils contents, downstream Barroca Grande tailing, are increased when compared with the local Bk soils. The mechanical dispersion, due to erosion, is the main contamination source. The chemical extraction demonstrates that the trace metals distribution and accumulation in S. Francisco de Assis soils is related to sulfides, but also to amorphous or poorly crystalline iron oxide phases. The partitioning study allowed understanding the local chemical elements mobility and precipitation processes, giving rise to the contamination dispersion model of the study area. The wind and hydrological factors are responsible for the chemical elements transport mechanisms, the water being the main transporter medium and soils as one of the possible retention media

    Spider species richness and sampling effort at CracraftŽS Belém Area of Endemism

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    Feeding behaviour of broiler chickens: a review on the biomechanical characteristics

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    Students’ Views on Difficulties in Learning Histology

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    The aim of this study was to provide a better understanding of the main difficulties hindering undergraduate biology students in learning histology. The study utilized a self‐administered questionnaire which included three closed‐ended and two open‐ended questions: (1) if students had difficulty in learning about each tissue type; (2) what might be the problem in learning about the tissue at hand; (3) which topics were the most difficult; (4) what were the possible reasons that made image identification of tissue types difficult; and (5) how to improve the course curriculum from a student perspective. The survey was administered to 139 undergraduate biology students enrolled in a histology course, of which 101 surveys were completed and analyzed both qualitatively and quantitatively. The topics that students experienced the most difficulties with were: nervous tissue, plant tissues, bone tissues, and glandular epithelial tissue. The main reasons students experienced difficulties with these tissue types, according to the students themselves, were the nature of the topic, grasping the terminology used, and insufficient teaching time. Students suggested the adoption of strategies such as: teaching based on practical tasks; reducing the content of the histology curriculum; adding anatomy subjects; and making histology education more interesting.This research was supported by the Teaching Program Networks from the Institute of Education Sciences at University of Alicante; Analysis of the difficulties in the learning of Histology Network (4146)
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