Evaluation of the immunoreactivity of nerve growth factor and tropomyosin receptor kinase A in the esophagus of noninfected and infected individuals with Trypanosoma cruzi.

Megaesophagus is one of the major manifestations of the chronic phase of Chagas disease. Its primary symptom is generally dysphagia due to disturbance in the lower esophageal sphincter. Microscopically, the affected organ presents denervation, which has been considered as consequence of an inflammatory process that begins at the acute phase and persists in the chronic phase. Inflammatory infiltrates are composed of lymphocytes, macrophages, natural killer cells, mast cells, and eosinophils. In this study, we evaluated the immunoreactivity of nerve growth factor (NGF), and of its receptor tropomyosin receptor kinase A (TrkA), molecules that are well known for having a relevant role in neuroimmune communication in the gastrointestinal tract. Esophageal samples obtained via autopsy or surgery procedures from six noninfected individuals, six infected individuals without megaesophagus, and six infected individuals with megaesophagus were analyzed. Infected individuals without megaesophagus presented increased numbers of NGF immunoreactive (IR) mast cells and increased areas of TrkA-IR epithelial cells and inner muscle cells. Infected individuals with megaesophagus showed increased numbers of NGF-IR eosinophils and mast cells, TrkA-IR eosinophils and mast cells, increased area of NGF-IR epithelial cells, and increased areas of TrkA-IR epithelials cells and inner muscle cells. The data presented here point to the participation of NGF and its TrkA receptor in the pathology of chagasic megaesophagus.

Future Directions of Training and Fieldwork in Diversity Issues in Applied Behavior Analysis.

This paper examines the perceptions of behavior-analytic professionals holding credentials through the Behavior Analyst Certification Board® (BACB®)-including Board Certified Behavior Analysts-Doctoral™, Board Certified Behavior Analysts®, and Board Certified Assistant Behavior Analysts®-regarding multiculturalism and diversity issues in their graduate training, fieldwork, and supervision. This paper predominantly focuses on future directions for improving graduate training, fieldwork, and supervision requirements in the field of applied behavior analysis (ABA) to produce more culturally competent professionals. Results from a preliminary survey of BACB® certificants (N = 575) are included to provide a context for recommendations on how to move the field of ABA forward to enhance the training and preparation of future credentialed professionals.

Membrane cholesterol regulates lysosome-plasma membrane fusion events and modulates Trypanosoma cruzi invasion of host cells.

BACKGROUND: Trypomastigotes of Trypanosoma cruzi are able to invade several types of non-phagocytic cells through a lysosomal dependent mechanism. It has been shown that, during invasion, parasites trigger host cell lysosome exocytosis, which initially occurs at the parasite-host contact site. Acid sphingomyelinase released from lysosomes then induces endocytosis and parasite internalization. Lysosomes continue to fuse with the newly formed parasitophorous vacuole until the parasite is completely enclosed by lysosomal membrane, a process indispensable for a stable infection. Previous work has shown that host membrane cholesterol is also important for the T. cruzi invasion process in both professional (macrophages) and non-professional (epithelial) phagocytic cells. However, the mechanism by which cholesterol-enriched microdomains participate in this process has remained unclear. METHODOLOGY/PRINCIPAL FINDING: In the present work we show that cardiomyocytes treated with MßCD, a drug able to sequester cholesterol from cell membranes, leads to a 50% reduction in invasion by T. cruzi trypomastigotes, as well as a decrease in the number of recently internalized parasites co-localizing with lysosomal markers. Cholesterol depletion from host membranes was accompanied by a decrease in the labeling of host membrane lipid rafts, as well as excessive lysosome exocytic events during the earlier stages of treatment. Precocious lysosomal exocytosis in MßCD treated cells led to a change in lysosomal distribution, with a reduction in the number of these organelles at the cell periphery, and probably compromises the intracellular pool of lysosomes necessary for T. cruzi invasion. CONCLUSION/SIGNIFICANCE: Based on these results, we propose that cholesterol depletion leads to unregulated exocytic events, reducing lysosome availability at the cell cortex and consequently compromise T. cruzi entry into host cells. The results also suggest that two different pools of lysosomes are available in the cell and that cholesterol depletion may modulate the fusion of pre-docked lysosomes at the cell cortex.

Um Megazord contra a anticiência: a ciência e a divulgação científica no Science Vlogs Brasil

Esta pesquisa analisa o discurso sobre ciência e divulgação científica nos canais de vídeos do Science Vlogs Brasil, que reúne vlogs de divulgação da ciência no YouTube. Utilizamos como aporte teórico a Análise de Discurso (AD) de linha francesa, cujo principal representante é o filósofo Michel Pêcheux, em diálogo com a Teoria Semiolinguística (TS) de Patrick Charaudeau, que foi a base utilizada para a construção do dispositivo de análise. A TS nos permitiu examinar a troca de efeitos de sentidos entre os vlogueiros do Science Vlogs Brasil e seus interlocutores, o contrato de comunicação em que estão empenhados, e a encenação linguageira (mise-en-scène) realizada durante a situação de comunicação. Por meio dessas referências e utilizando ainda estudos das áreas da filosofia e sociologia da ciência e da divulgação científica, tentamos revelar essas imagens da ciência, da divulgação científica e dos interlocutores, construídas e projetadas nos discursos dos locutores dos canais associados ao SVBR, no YouTube. Vimos que imagem da ciência como lugar de verdade e poder, extensiva àqueles que fazem parte da comunidade científica, apesar de anacrônica, e de receber um olhar crítico dos principais autores e filósofos atuais que se dedicam a esse estudo, ainda resiste e é transmitida no discurso de cientistas, divulgadores e jornalistas. O aporte das Novas Tecnologias de Informação e da web 2.0 instauram novas relações do homem com a linguagem, instituindo novas materialidades, como os vlogs do YouTube, espaços de produção e circulação do discurso de divulgação científica, que também sofrem determinações dessa outra linguagem e modo de fazer. As análises mostraram que tanto a memória discursiva dos divulgadores científicos quanto as novas TICs interferem nos efeitos de sentido, estratégias e projeções do sujeito-divulgador científico, que determinado pela ordem da ciência, da web 2.0 e do YouTube, constrói e materializa em seu discurso significados sobre a ciência o papel da divulgação científica e sobre seus interlocutores.