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Traumatic social experiences redefine socially motivated behaviors to enhance safety and survival. Although many brain regions have been implicated in signaling a social threat, the mechanisms by which global neural networks regulate such motivated behaviors remain unclear. To address this issue, we first combined traditional and modern behavioral tracking techniques in mice to assess both approach and avoidance, as well as sub-second behavioral changes, during a social threat learning task. We were able to identify previously undescribed body and tail movements during social threat learning and recognition that demonstrate unique alterations into the behavioral structure of social motivation. We then utilized inter-regional correlation analysis of brain activity after a mouse recognizes a social threat to explore functional communication amongst brain regions implicated in social motivation. Broad brain activity changes were observed within the nucleus accumbens, the paraventricular thalamus, the ventromedial hypothalamus, and the nucleus of reuniens. Inter-regional correlation analysis revealed a reshaping of the functional connectivity across the brain when mice recognize a social threat. Altogether, these findings suggest that reshaping of functional brain connectivity may be necessary to alter the behavioral structure of social motivation when a social threat is encountered.
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Mangroves forests may be important sinks of carbon in coastal areas but upon their death, these forests may become net sources of carbon dioxide (CO2) and methane (CH4) to the atmosphere. Here we assessed the spatial and temporal variability in soil CO2 and CH4 fluxes from dead mangrove forests and paired intact sites in SE-Brazil. Our findings demonstrated that during warmer and drier conditions, CO2 soil flux was 183 % higher in live mangrove forests when compared to the dead mangrove forests. Soil CH4 emissions in live forests were > 1.4-fold higher than the global mangrove average. During the wet season, soil GHG emissions dropped significantly at all sites. During warmer conditions, mangroves were net sources of GHG, with a potential warming effect (GWP100) of 32.9 ± 10.2 (±SE) Mg CO2e ha-1 y-1. Overall, we found that dead mangroves did not release great amounts of GHG after three years of forest loss.
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Dióxido de Carbono , Monitoramento Ambiental , Gases de Efeito Estufa , Metano , Solo , Áreas Alagadas , Brasil , Gases de Efeito Estufa/análise , Solo/química , Dióxido de Carbono/análise , Metano/análise , FlorestasRESUMO
BACKGROUND: Alzheimer's disease (AD) is a neurodegenerative disorder characterized by progressive cognitive impairment and memory loss. One of the hallmarks in AD is amyloid-ß peptide (Aß) accumulation, where the soluble oligomers of Aß (AßOs) are the most toxic species, deteriorating the synaptic function, membrane integrity, and neuronal structures, which ultimately lead to apoptosis. Currently, there are no drugs to arrest AD progression, and current scientific efforts are focused on searching for novel leads to control this disease. Lignans are compounds extracted from conifers and have several medicinal properties. Eudesmin (Eu) is an extractable lignan from the wood of Araucaria araucana, a native tree from Chile. This metabolite has shown a range of biological properties, including the ability to control inflammation and antibacterial effects. OBJECTIVE: In this study, the neuroprotective abilities of Eu on synaptic failure induced by AßOs were analyzed. METHODS: Using neuronal models, PC12 cells, and in silico simulations we evaluated the neuroprotective effect of Eu (30 nM) against the toxicity induced by AßOs. RESULTS: In primary cultures from mouse hippocampus, Eu preserved the synaptic structure against AßOs toxicity, maintaining stable levels of the presynaptic protein SV2 at the same concentration. Eu also averted synapsis failure from the AßOs toxicity by sustaining the frequencies of cytosolic Ca2+ transients. Finally, we found that Eu (30 nM) interacts with the Aß aggregation process inducing a decrease in AßOs toxicity, suggesting an alternative mechanism to explain the neuroprotective activity of Eu. CONCLUSION: We believe that Eu represents a novel lead that reduces the Aß toxicity, opening new research venues for lignans as neuroprotective agents.
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Doença de Alzheimer , Lignanas , Fármacos Neuroprotetores , Ratos , Camundongos , Animais , Peptídeos beta-Amiloides/metabolismo , Doença de Alzheimer/metabolismo , Lignanas/farmacologia , Células PC12 , Fármacos Neuroprotetores/farmacologiaRESUMO
Resumo: Introdução: A empatia, tida como uma das características mais marcantes dos grandes profissionais médicos, é o elemento central da relação médico-paciente e do cuidado centrado na pessoa. Objetivo: Este estudo teve como objetivo investigar como se manifestam os níveis de empatia em estudantes de Medicina ao longo da graduação. Método: Trata-se de um estudo de natureza quantitativa, analítica, observacional e transversal, realizado numa instituição privada de ensino superior, situada no Nordeste do Brasil. A pesquisa se deu por meio da aplicação da Escala Jefferson de Empatia Médica - versão para estudantes (JSPE-vs) e da correlação dos dados obtidos na escala com o período da graduação e o perfil sociodemográfico dos estudantes, a fim de verificar quais correlações se mostram significativas para a expressão dos níveis de empatia dos estudantes, bem como se há erosão dela durante a formação. A coleta de dados ocorreu entre os meses de outubro e novembro de 2020. Contou com 193 participantes entre ingressantes, intermediários e concluintes do curso de Medicina. A amostragem utilizada foi por acessibilidade e conveniência. Resultados: A pontuação média global do nível de empatia no conjunto de todos os participantes do estudo (n = 193) foi de 123,56 ± 11,73. Quanto ao período, obteve-se o seguinte resultado: ingressantes = 124,78 ± 9,85, intermediários = 124,00 ± 11,87 e concluintes = 120,63 ± 13,57. Não se verificou diferença estatística entre os escores global ou por fator na comparação entre os três grupos estudados. E na correlação da JSPE-vs com o perfil sociodemográfico, as variáveis sexo feminino e motivo de escolha do curso por vocação foram preditoras de escores maiores de empatia. Conclusão: Não se evidenciou erosão dos níveis de empatia nos estudantes de Medicina ao longo da graduação, e os discentes do sexo feminino e aqueles que escolheram o curso por se sentirem vocacionados para tal mostraram níveis de empatia significativamente maiores. Mais estudos sobre esse tema são fundamentais, tendo em vista a importância de uma postura técnico-científico-humanística equilibrada para o exercício de uma medicina de excelência.
Abstract: Introduction: Empathy, considered one of the most remarkable characteristics of great medical professionals, is the central element of the doctor-patient relationship and of person-centered care. Objective: To investigate how levels of empathy are manifested in medical students throughout their undergraduate course. Method: This is a quantitative, analytical, observational and cross-sectional study, carried out in a private higher education institution, located in the northeast of Brazil. The research was carried out by applying the Jefferson Scale of Empathy-Student version (JSE-S) and the correlation of the data obtained in the scale with the undergraduate school period and sociodemographic profile of the students, aiming to verify which correlations were significant for the expression of students' empathy levels, as well as whether there is an erosion during training. Data collection took place between the months of October and November 2020. The study assessed 193 participants, including students attending the first year, an intermediate year and last year of the medical course. The sampling method used was by accessibility and convenience. Results: The global average score of the level of empathy in the group of all study participants (n = 193) was 123.56 ± 11.73. Whereas, by period, it was 124.78 ± 9.85 for first-year students, 124.00 ± 11.87 for intermediate-year students and 120.63 ± 13.57 for last-year students. There was no statistical difference between global scores or by psychometric factor when comparing the three studied groups. As for the correlation of JSE-S with the sociodemographic profile, the variables female gender and reason for choosing the course due to vocation were predictors of higher empathy scores. Conclusion: There was no evidence of empathy erosion regarding the levels of empathy among medical students throughout their undergraduate course, and female students and those who chose the course because they felt they had a vocation for Medicine showed significantly higher levels of empathy. More studies on this topic are essential, considering the importance of a balanced technical-scientific-humanistic posture to enable a medical practice of excellence.
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Resumo Objetivo Elaborar e validar tecnologias educativas para o cuidado domiciliar de pessoas com hemofilia em infusão endovenosa do fator de coagulação. Método Estudo metodológico, desenvolvido em três etapas: elaboração de tecnologias educativas, avaliação de conteúdo e aparência por juízes e apreciação por pessoas com hemofilia. As tecnologias educativas − cartilha e infográfico − foram elaboradas mediante revisão de literatura. Na etapa de avaliação com juízes, foi utilizada a técnica Delphi em duas rodadas, por meio do Índice de Validade de Conteúdo, concordância superior a 0,80 em relação a clareza de linguagem, pertinência prática e relevância teórica. Na avaliação com o público-alvo, foi considerado o nível de concordância de respostas positivas maior ou igual a 80% nos itens de organização, o estilo de escrita, a aparência e a motivação para a leitura. Resultados A cartilha apresentou índice de validade de conteúdo global de 0,88 na primeira rodada e 0,98 na segunda; e o infográfico, 0,88 na primeira rodada e 0,97 na segunda. Na apreciação das tecnologias educativas pelo público-alvo, o nível de concordância das respostas positivas foi superior a 80%. Conclusão Este estudo elaborou tecnologias educativas, cartilha e infográfico, que poderão contribuir com a adesão ao tratamento e promoção do cuidado, por meio de padronização das orientações às pessoas com hemofilia em infusão endovenosa domiciliar.
Resumen Objetivo Elaborar y validar tecnologías educativas para el cuidado domiciliario de personas con hemofilia sobre la infusión intravenosa domiciliaria del factor de coagulación. Métodos Estudio metodológico desarrollado en tres etapas: elaboración de tecnologías educativas, evaluación de contenido y apariencia por jueces y valoración por parte de personas con hemofilia. Las tecnologías educativas (cartilla e infográfico) fueron elaboradas mediate revisión de literatura. En la etapa de evaluación con jueces, se utilizó el método Delphi en dos rondas, por medio del Índice de Validez de Contenido, concordancia superior a 0,80 con relación a la claridad del lenguaje, pertinencia práctica y relevancia teórica. En la evaluación con el público destinatario, se consideró el nivel de concordancia de respuestas positivas mayor o igual a 80 % en los ítems organización, estilo de escritura, apariencia y motivación para lectura. Resultados La cartilla presentó un Índice de Validez de Contenido global de 0,88 en la primera ronda y 0,98 en la segunda. El infográfico presentó 0,88 en la primaria ronda y 0,97 en la segunda. En la valoración de las tecnologías educativas por el público destinatario, el nivel de concordancia de las respuestas positivas fue superior al 80 %. Conclusión En este estudio se elaboraron tecnologías educativas, cartilla e infográfico, que podrán contribuir con la adherencia al tratamiento y promoción del cuidado, mediante la estandarización de las instrucciones a personas con hemofilia sobre infusión intravenosa domiciliaria.
Abstract Objective To develop and validate educational technologies for home care of people with hemophilia on intravenous infusion of clotting factor. Method This is a methodological study, developed in three stages: development of educational technologies, content and appearance assessment by judges, and appraisal by people with hemophilia. The educational technologies - a booklet and an infographic - were developed through a literature review. In the assessment stage with judges, the Delphi technique was used in two rounds, through Content Validity Index, agreement greater than 0.80 in regarding clarity of language, practical relevance, and theoretical relevance. In the assessment with the target audience, the level of agreement of positive responses greater than or equal to 80% in the items of organization, writing style, appearance and motivation for reading was considered. Results The booklet presented a global content validity index of 0.88 in the first round and 0.98 in the second; and the infographic, 0.88 in the first round and 0.97 in the second. In the assessment of educational technologies by the target audience, the level of agreement of positive responses was higher than 80%. Conclusion This study developed educational technologies, a booklet and an infographic, which could contribute to adherence to treatment and promotion of care, by standardizing the guidelines for people with hemophilia in intravenous infusion at home.
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Humanos , Masculino , Feminino , Adulto , Pessoa de Meia-Idade , Infusões Intravenosas , Fatores de Coagulação Sanguínea , Terapia por Infusões no Domicílio , Tecnologia Educacional , Materiais Educativos e de Divulgação , Hemofilia A/terapia , Assistência DomiciliarRESUMO
α-Synuclein (αSyn) species can be detected in synaptic boutons, where they play a crucial role in the pathogenesis of Parkinson's Disease (PD). However, the effects of intracellular αSyn species on synaptic transmission have not been thoroughly studied. Here, using patch-clamp recordings in hippocampal neurons, we report that αSyn oligomers (αSynO), intracellularly delivered through the patch electrode, produced a fast and potent effect on synaptic transmission, causing a substantial increase in the frequency, amplitude and transferred charge of spontaneous synaptic currents. We also found an increase in the frequency of miniature synaptic currents, suggesting an effect located at the presynaptic site of the synapsis. Furthermore, our in silico approximation using docking analysis and molecular dynamics simulations showed an interaction between a previously described small anti-amyloid beta (Aß) molecule, termed M30 (2-octahydroisoquinolin-2(1H)-ylethanamine), with a central hydrophobic region of αSyn. In line with this finding, our empirical data aimed to obtain oligomerization states with thioflavin T (ThT) and Western blot (WB) indicated that M30 interfered with αSyn aggregation and decreased the formation of higher-molecular-weight species. Furthermore, the effect of αSynO on synaptic physiology was also antagonized by M30, resulting in a decrease in the frequency, amplitude, and charge transferred of synaptic currents. Overall, the present results show an excitatory effect of intracellular αSyn low molecular-weight species, not previously described, that are able to affect synaptic transmission, and the potential of a small neuroactive molecule to interfere with the aggregation process and the synaptic effect of αSyn, suggesting that M30 could be a potential therapeutic strategy for synucleinopathies.
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Isoquinolinas/farmacologia , Neurônios/citologia , alfa-Sinucleína/química , alfa-Sinucleína/metabolismo , Animais , Benzotiazóis/farmacologia , Células Cultivadas , Humanos , Interações Hidrofóbicas e Hidrofílicas , Camundongos , Simulação de Acoplamento Molecular , Simulação de Dinâmica Molecular , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Ligação Proteica , Domínios Proteicos , Ratos , Transmissão SinápticaRESUMO
Campylobacter spp. is an emerging pathogen that causes gastroenteritis in humans and the consumption of dairy food can characterize sources of infection. We aimed to verify the viability and a presence of transcripts associated with characteristics of virulence and adaptation of C. jejuni isolated from Minas Frescal cheeses, produced with contaminated milk and stored under refrigeration for up to ten days. The samples were analyzed for bioindicators, Campylobacter spp., pH, acidity, moisture and sodium chloride. Campylobacter spp. recovered were evaluated for the production of transcripts of: ciaB, dnaJ, p19 and sodB. The results were correlated with the viability of C. jejuni and changes in their transcriptome. Storage at lowtemperatures reduced C. jejuni from the first to the fourth day. The variations in humidity, pH and acidity influenced the decreasing of C. jejuni. There was a reduction in transcripts' production of the four genes, more pronounced on the fourth day, indicating the inability of the microorganism to perform its metabolic activities, due to the conditions of injury. Despite the presence of mechanisms of virulence and adaptation, C. jejuni could not remain viable four days after production. However, consumption of fresh cheese contaminated with Campylobacter jejuni can be a source of infection when consumed up to four days after production.
Campylobacter spp. é um patógeno emergente que causa gastroenterite em seres humanos e o consumo de produtos lácteos pode caracterizar fontes de infecção. O objetivo deste estudo foi verificar a viabilidade e a presença de transcritos associadas a características de virulência e adaptação de C. jejuniisoladas de queijos frescos, produzidos com leite contaminado e mantidos refrigeradas por dez dias. Foram analisados bioindicadores, Campylobacter spp., pH, acidez, umidade e cloreto de sódio. Campylobacter spp. recuperados foram avaliados quanto à produção dos transcritos: ciaB, dnaJ, p19 e sodB. Os resultados foram correlacionados com a viabilidade de C. jejuni e alterações no transcriptoma. O armazenamento em baixas temperaturas reduziu C. jejuni do primeiro ao quarto dia. As variações na umidade, pH e acidez influenciaram a queda de C. jejuni. Houve uma redução na produção de transcritos dos quatro genes, mais pronunciada no quarto dia, indicando a incapacidade do micro-organismo em realizar suas atividades metabólicas, devido às condições de injúria. Apesar da presença de mecanismos de virulência e adaptação, C. jejuni não permaneceu viável quatro dias após a produção. Porém, o consumo de queijo fresco contaminado com Campylobacter jejunipode ser uma fonte de infecção quando consumido até quatro dias após a produção.
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Infecções por Campylobacter , Queijo , Campylobacter jejuni , Virulência , Laticínios , Gastroenterite , Infecções , NoxasRESUMO
This study simulated the contamination of two varieties of infant milk formulas (homemade and commercial) with 103 and 104 CFU/mLof Campylobacter jejuni, that were kept under refrigeration (4-7ºC) for up to 48 hours. The aim of this study was to verify the maintenance of the viability and ability of Campylobacter jejuni to produce transcripts of virulence and resistance to stress conditions during periods of 0 (after preparation), 24 and 48 hours. C. jejuni remained viable during all analyzed stages and thepresence of coliforms was not detected. In general, the counts reduced 1 log cycle after 48 hours for all samples, except the 104 CFU/mL inoculum of commercial formula, which reduced 2 log cycles, indicating greater injury of C. jejuni in this food matrix. C. jejuni showed to be more adapted to homemade matrix, due to high transcription of the gene related to cell invasion, ciaB, and more susceptible in the commercial matrix, due to the high transcription of genes related to conditions of stress tolerance (dnaJ, p19, sodB). The low infective dose of C. jejuni coupled with greater vulnerability of children less than five years indicate the need for care in the preparation and maintenance of infant formulas, to prevent the use of contaminated raw material and cross-contamination, especially in homemade formulations
Este estudo simulou a contaminação de duas variedades de fórmulas de leite infantil com Campylobacter jejuni (caseiras e comerciais), que foram mantidas sob refrigeração (4-7ºC) por até 48 horas. O objetivo do estudo foi verificar a manutenção da viabilidade e capacidade de produzir transcritos de virulência e resistência a condições de estresse durante os períodos de 0 (após preparação), 24 e 48 horas. C. jejunipermaneceu viável durante todas as etapas analisadas e a presença de coliformes não foi detectada. Em geral, as contagens reduziram 1 ciclo log após 48 horas para todas as amostras, exceto o inóculo de 104 CFU/mL na fórmula comercial, que reduziu 2 ciclos logarítmicos, indicando maior lesão de C. jejuni nesta matriz alimentar. C. jejuni mostrou-se mais adaptado à matriz popular, devido à alta transcrição do gene relacionado à invasão celular, ciaB, e mais suscetível na matriz comercial, devido à alta transcrição de genes relacionados a tolerância a condições de estresse (dnaJ, p19, sodB). A baixa dose infectante de C. jejuni, juntamente com maior vulnerabilidade de crianças menores de cinco anos, indicam a necessidade de cuidados na preparação e manutenção de fórmulas infantis, para prevenir o uso de matéria-prima contaminada e contaminação cruzada, especialmente em formulações caseiras.
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Campylobacter jejuni , Leite , Gastroenterite , LactenteRESUMO
RESUMO O estresse corresponde a uma resposta física, psíquica e hormonal que ocorre quando o organismo necessita se adaptar frente a uma situação desafiadora. É uma das respostas mais recorrentes no meio acadêmico devido à rotina exaustiva e conteúdo denso que exigem responsabilidade e competitividade dos estudantes. Na graduação médica, somam-se a estes fatores a preocupação do estudante em aprender o conteúdo discutido em aulas e a pressão exercida pelos próprios acadêmicos, além da cobrança da sociedade. Diante da relevância do tema, este estudo teve como objetivo avaliar a ocorrência do estresse durante a graduação médica em acadêmicos de uma universidade privada da região do Alto Tietê, no Estado de São Paulo. Foram aplicados dois instrumentos de pesquisa, o Inventário de Sintomas de Estresse para Adultos de Lipp (ISSL) e a Escala de Estresse Percebido (PSS), em 420 estudantes (67,14% do sexo feminino) matriculados entre os ciclos básico (primeiro e segundo ano) e profissionalizante (terceiro ao sexto ano). Todos os participantes da pesquisa eram voluntários. De acordo com o PSS, foram verificados maiores níveis de estresse entre os alunos do primeiro ao terceiro ano quando comparados aos discentes do quarto ao sexto ano. O ISSL demonstrou a ocorrência de estresse em 65% dos estudantes. Entre estes, 9,04% se encontravam em fase de "quase exaustão" e 0,95% na fase de "exaustão", as fases mais elevadas dos níveis de estresse, sendo que a ocorrência de sintomas teve prevalência no sexo feminino. Em todas as turmas analisadas, os alunos do primeiro ao terceiro ano apresentaram maior índice de estresse em relação aos demais, o que pode estar associado à distribuição dos conteúdos curriculares com predomínio de disciplinas conceituais, assim como ao processo de transição de conteúdos teóricos para atividades práticas. Estes resultados podem estar vinculados à adaptação dos alunos à rotina das universidades, às disciplinas cursadas e às obrigações que o ensino superior exige.
ABSTRACT Stress corresponds to physical, psychological and hormonal responses that occur when the body needs to adapt to a challenging situation. It is one of the most recurrent responses in the academic world due to the exhaustive routine and dense content that demand responsibility and competitiveness from the students. In medical undergraduate schools, we add to these factors the student's concern to learn the content that was discussed in class and the pressure exerted by the students themselves, in addition to the demands of society. Given the relevance of the topic, this study aimed to evaluate the occurrence of stress during medical undergraduate school in students from a private university in the Alto Tietê region, in the state of São Paulo. Two research instruments, the Lipp Adult Stress Symptom Inventory (ISSL) and the Perceived Stress Scale (PSS), were applied to n= 420 undergraduate students (67.14% females) attending the basic (first and second years) and vocational cycles (third to sixth years), and all participants were volunteers. According to the PSS, higher levels of stress were observed in students from the first to the third years, when compared to students from the fourth to the sixth years of medical school. The ISSL demonstrated the occurrence of stress in 65% of the students, of which 9.04% were in the "near exhaustion" phase and 0.95% in the "exhaustion" phase, which represent the highest levels of stress, with the occurrence of symptoms being more prevalent in female students. Among all the analyzed groups, students attending the first to the third years showed a higher stress index than the others, which may be associated to the distribution of curricular contents with the predominance of conceptual disciplines, as well as the process of transition from theoretical contents to practical activities. These results may be related to the students' adaptation to the university routine, to the courses taken and to the obligations that higher education demands.
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Alpha-synuclein is a presynaptic protein expressed throughout the central nervous system, and it is the main component of Lewy bodies, one of the histopathological features of Parkinson's disease (PD) which is a progressive and irreversible neurodegenerative disorder. The conformational flexibility of α-synuclein allows it to adopt different conformations, i.e., bound to membranes or form aggregates, the oligomers are believed to be the more toxic species. In this review, we will focus on two major features of α-synuclein, transmission and toxicity, that could help to understand the pathological characteristics of PD. One important feature of α-synuclein is its ability to be transmitted from neuron to neuron using mechanisms such as endocytosis, plasma membrane penetration or through exosomes, thus propagating the Lewy body pathology to different brain regions thereby contributing to the progressiveness of PD. The second feature of α-synuclein is that it confers cytotoxicity to recipient cells, principally when it is in an oligomeric state. This form causes mitochondrial dysfunction, endoplasmic reticulum stress, oxidative stress, proteasome impairment, disruption of plasma membrane and pore formation that lead to apoptosis pathway activation and consequent cell death. The complexity of α-synuclein oligomerization and formation of toxic species could be a major factor for the irreversibility of PD and could also explain the lack of successful therapies to halt the disease.
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It has been postulated that the accumulation of extracellular α-synuclein (α-syn) might alter the neuronal membrane by formation of 'pore-like structures' that will lead to alterations in ionic homeostasis. However, this has never been demonstrated to occur in brain neuronal plasma membranes. In this study, we show that α-syn oligomers rapidly associate with hippocampal membranes in a punctate fashion, resulting in increased membrane conductance (5 fold over control) and the influx of both calcium and a fluorescent glucose analogue. The enhancement in intracellular calcium (1.7 fold over control) caused a large increase in the frequency of synaptic transmission (2.5 fold over control), calcium transients (3 fold over control), and synaptic vesicle release. Both primary hippocampal and dissociated nigral neurons showed rapid increases in membrane conductance by α-syn oligomers. In addition, we show here that α-syn caused synaptotoxic failure associated with a decrease in SV2, a membrane protein of synaptic vesicles associated with neurotransmitter release. In conclusion, extracellular α-syn oligomers facilitate the perforation of the neuronal plasma membrane, thus explaining, in part, the synaptotoxicity observed in neurodegenerative diseases characterized by its extracellular accumulation. We propose that α-synuclein (α-syn) oligomers form pore-like structures in the plasma membrane of neurons from central nervous system (CNS). We believe that extracellular α-syn oligomers facilitate the formation of α-syn membrane pore-like structures, thus explaining, in part, the synaptotoxicity observed in neurodegenerative diseases characterized by its extracellular accumulation. We think that alterations in ionic homeostasis and synaptic vesicular depletion are key steps that lead to synaptotoxicity promoted by α -syn membrane pore-like structures.
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Membrana Celular/metabolismo , Líquido Extracelular/metabolismo , Hipocampo/metabolismo , Neurônios/metabolismo , Transmissão Sináptica/fisiologia , alfa-Sinucleína/metabolismo , Animais , Encéfalo/citologia , Encéfalo/metabolismo , Células Cultivadas , Feminino , Hipocampo/citologia , Técnicas de Cultura de Órgãos , Gravidez , Ratos Sprague-DawleyRESUMO
The objective of this study was to analyze the behavior of activated carbons with different chemical and textural natures in the adsorption of three tetracyclines (TCs) (tetracycline, oxytetracycline, and chlortetracycline). We also assessed the influence of the solution pH and ionic strength on the adsorption of these compounds and studied their removal by the combined use of microorganisms and activated carbon (bioadsorption). Sludge-derived materials were also used to remove TC from water. The capacity of these materials to adsorb TC was very high and was much greater than that of commercial activated carbon. This elevated adsorption capacity (512.1-672.0 mg/g) is explained by the high tendency of TC to form complex ions with some of the metal ions present in these materials. The medium pH and presence of electrolytes considerably affected TCs adsorption on commercial activated carbon. These results indicate that electrostatic adsorbent-adsorbate interactions play an important role in TC adsorption processes when conducted at pH values that produce TC deprotonation. The presence of bacteria during the TCs adsorption process decreases their adsorption/bioadsorption on the commercial activated carbon, weakening interactions between the adsorbate and the microfilm formed on the carbon surface. The adsorptive capacity was considerably lower in dynamic versus static regime, attributable to problems of TC diffusion into carbon pores and the shorter contact time between adsorbate and adsorbent.