Search

Tese (doutorado)—Universidade de Brasília, Faculdade de Ciências da Saúde, Programa de Pós-Graduação em Ciências da Saúde, 2017. Introdução: Apesar do schwannoma vestibular (SV) ser um tumor do nervo vestibular, a perda auditiva (PA) é o sintoma mais comum, presente em 95% dos pacientes. Entretanto, a fisiopatologia dessa PA ainda é desconhecida. A compressão do nervo coclear pelo tumor não é capaz de elucidar completamente sua fisiopatologia e levanta a hipótese que a PA provocada pelo SV pode estar relacionada às substâncias secretadas pelo tumor presentes no líquido que banha a cóclea. Objetivo: Este trabalho identifica se as vesículas extracelulares (VE) derivadas do SV são mediadores no dano de células cocleares. Métodos: VEs foram isoladas de cultura de linhagem celular (células HEI-193) e de cultura de células primárias de SV de pacientes com boa audição (BA) e de pacientes com PA. As VEs foram caracterizadas usando o Nanosight e microscopia eletrônica de transmissão. O conteúdo de RNA das VEs foi extraído. O efeito das VEs sobre cultura de neurônios do gânglio espiral e sobre cultura ex-vivo de cócleas de camundongos foi estudado usando um sistema de cultura duplo e pela marcação das VEs com PKH-67. Mudanças provocadas pelas VEs nas células cocleares foram quantificadas utilizando imunohistoquímica e microscopia confocal. Transfecção da linhagem celular de SV com plasmídeo contendo GFP (proteína fluorescente verde) foi confirmada com reação em cadeia da polimerase via transcriptase reversa (RT-PCR). Resultados: Células tumorais humanas de pacientes com PA produzem VEs que podem causar danos em neurônios do gânglio espiral. Em contraste, VEs de células tumorais associados com BA não foram capazes de provocar danos as células cocleares. Conclusão: Este é o primeiro relato de VEs derivadas de SV. Essas VEs quando originadas de SV associados a PA eram capazes de causar danos seletivos nas células cocleares, identificando assim um novo e potencial mecanismo de perda auditiva neurossensorial em pacientes com SV. Introduction: Although vestibular schwannoma (VS) is a tumor of the vestibular nerve, hearing loss (HL) is the most frequent symptom, presenting in 95% of the patients. However, the pathophysiology of HL is not well understood. The compression of coclear nerve by the tumor is not able to explain the cause of hearing loss perfectly and raise the hypothesis that HL may be related to tumor secretome that reach the cochlea. Objective: This research explores the role of VS-secreted extracellular vesicles (EVs) as a major contributing factor in cochlear cells damage. Methods: EVs were isolated from VS cell line HEI-193 and primary cultured human VS cells from patients with good hearing or poor hearing. The EVs were characterized using a Nanosight device and transmission electron microscopy and by extracting their RNA content. The EVs’ effects on cultured murine spiral ganglion cells and organotypic cochlear cultures were studied using a transwell dual-culture system and by direct labeling of EVs with PKH-67 dye. EV-induced changes in cochlear cells were quantified using confocal immunohistochemistry. Transfection of VS cells with a green fluorescent protein–containing plasmid was confirmed with reverse transcription PCR. Results: Human VS cells, from patients with poor hearing, produced EVs that could damage spiral ganglion neurons. In contrast, EVs derived from VS cells from patients with good hearing did not damage the cultured cochlear cells. Conclusion: This is the first report on EVs derived from VSs and on the capacity of EVs from VSs from patients with hearing loss to selectively damage cochlear cells, thereby identifying a potential novel mechanism of VS-associated sensorineural hearing loss.

An analysis of the dietary content of haematophagous insects can provide important information about the transmission networks of certain zoonoses. The present study evaluated the potential of polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis of the mitochondrial cytochrome B (cytb)gene to differentiate between vertebrate species that were identified as possible sources of sandfly meals. The complete cytb gene sequences of 11 vertebrate species available in the National Center for Biotechnology Information database were digested with Aci I, Alu I, Hae III and Rsa I restriction enzymes in silico using Restriction Mapper software. The cytb gene fragment (358 bp) was amplified from tissue samples of vertebrate species and the dietary contents of sandflies and digested with restriction enzymes. Vertebrate species presented a restriction fragment profile that differed from that of other species, with the exception of Canis familiaris and Cerdocyon thous. The 358 bp fragment was identified in 76 sandflies. Of these, 10 were evaluated using the restriction enzymes and the food sources were predicted for four: Homo sapiens (1), Bos taurus (1) and Equus caballus (2). Thus, the PCR-RFLP technique could be a potential method for identifying the food sources of arthropods. However, some points must be clarified regarding the applicability of the method, such as the extent of DNA degradation through intestinal digestion, the potential for multiple sources of blood meals and the need for greater knowledge regarding intraspecific variations in mtDNA.

Imaging of the cochlea and internal auditory canals are increasingly important nowadays because of the growing number of cochlear implants being performed throughout the world. We report a case of a 4-year-old boy who was born deaf and was being evaluated in our service for possible cochlear implantation. Audiometry disclosed profound bilateral deafness. The magnetic resonance imaging revealed only two nerves in each inner auditory canal: one in the anterior superior quadrant, identified as the facial nerve, and one on the posterior quadrants, representing both the superior and inferior vestibular nerves. The semicircular canals were not seen and the vestibule had dysplastic morphology. The diagnosis was bilateral agenesis of the cochlear nerves and semicircular canals.

Knowledge of the population in regards to stroke has clinical and epidemiological importance. Prompt identification of the symptoms means efficient medical attendance within the window of therapeutic opportunities reducing significantly the morbi-mortality. Our aim was to evaluate the level of knowledge of the population of Teresina (PI) concerning factors of risk, symptoms and treatment of stroke. The door-to-door study was carried out by means of a standardized application of questionnaire on risk factors, symptoms and attitude when faced with a stroke victim. 991 forms were selected. Factors of risk more cited were hypertension identified by 416 [42.0%] and hyperlipidemia 284 [28.7%]. The most remembered symptoms were headache 277 [28.0%] and hemiplegia 219 [22.1%]. 375 (37.8%) respondents were unable to identify any risk factors and and 410 (41.4%) any symptom. The lack of knowledge of the population of Teresina in relation to stroke reflects the need for intervention through public and professional educational campaigns.

Knowledge of the population in regards to stroke has clinical and epidemiological importance. Prompt identification of the symptoms means efficient medical attendance within the window of therapeutic opportunities reducing significantly the morbi-mortality. Our aim was to evaluate the level of knowledge of the population of Teresina (PI) concerning factors of risk, symptoms and treatment of stroke. The door-to-door study was carried out by means of a standardized application of questionnaire on risk factors, symptoms and attitude when faced with a stroke victim. 991 forms were selected. Factors of risk more cited were hypertension identified by 416 [42.0%] and hyperlipidemia 284 [28.7%]. The most remembered symptoms were headache 277 [28.0%] and hemiplegia 219 [22.1%]. 375 (37.8%) respondents were unable to identify any risk factors and and 410 (41.4%) any symptom. The lack of knowledge of the population of Teresina in relation to stroke reflects the need for intervention through public and professional educational campaigns. O conhecimento da população sobre doenças cerebrovasculares (DCV) possui importância clínica e epidemiológica. A rápida identificação dos sintomas significará atendimento médico eficiente dentro das janelas de oportunidades terapêuticas reduzindo significativamente a morbimortalidade. Objetivou-se avaliar o nível de conhecimento da população de Teresina (PI) acerca dos fatores de risco, sintomas e tratamento das DCV. O estudo populacional, porta-a-porta, foi conduzido mediante aplicação padronizada de um questionário sobre fatores de risco, sintomas e atitude diante de um caso de DCV. Foram eleitos 991 formulários preenchidos. Os fatores de risco mais citados foram hipertensão arterial identificada por 416 [42,0%] e hiperlipidemia 284 [28,7%]. Os sintomas mais lembrados foram cefaléia 277 [28,0%] e hemiplegia 219 [22,1%]. Não identificaram nenhum fator de risco 375 (37,8%) respondedores e 410 (41,4%), nenhum sintoma. O reduzido conhecimento da população de Teresina com relação às DCV reflete a necessidade de intervenção com campanhas educativas públicas e profissionais nesta população.