1,720,954 research outputs found
Esteroides anabólicos androgênicos: uma revisão cronológica
Get PDFA crescente utilização de esteroides anabólicos androgênicos tem se tornado uma preocupação social de progressão considerável na atualidade. Embasando-se nas propriedades hormonais, nos prováveis efeitos deletérios e nos esteroides anabólicos androgênicos mais usuais, o presente estudo científico, através do método de revisão de literatura narrativa, possibilita historiar as atribuições e propriedades dos esteroides anabólicos androgênicos de modo abrangente. As primeiras revelações da pesquisa contribuem para transmitir os interesses para as primeiras pesquisas e experimentações, cientificas ou não, até a idealização dos esteroides anabólicos androgênicos. Conta-se, então, através da datação de fatos, o progresso gradual dos esteroides anabólicos androgênicos: descoberta, isolamento, síntese, propalação, distribuição, comercialização até a indiscriminação de seu uso. Isto posto, é possível o esclarecimento das motivações do uso de esteroides anabólicos androgênicos no meio desportivo, bem como o conhecimento das propriedades fisiológicas que suscitam a alta procura destes sintéticos. A pesquisa ainda disponibiliza evidências sobre os índices de utilização de usuários recreacionais e competitivos, sendo esta última classe regularizada e fiscalizada por órgãos de influência mundial no combate ao uso de substâncias exógenas, independente do propósito (melhora física, melhora no desempenho ou performance) valendo-se de medidas corretivas aos atletas que fogem à regra. Quando, por fim, os efeitos imediatos dos esteroides anabólicos androgênicos colocados à prova por um grupo de pesquisadores que contestam a eficácia de um dos experimentos mais importantes da história da humanidade. Pretende-se, desta maneira, alcançar todas as classes populacionais, proporcionando-as conhecimento acerca dos esteroides anabólicos androgênicos, a partir de uma análise ampla proporcionada pelo histórico cronológico e descritivo sobre essas drogas, para alertá-las quanto as adversidades ocasionadas devido sua ministração através de campanhas sociais e educacionais
Estudo da atividade antileishmanial de um novo sal orgânico derivado de triazol em leishmania amazonensis
No full textLeishmaniasis is an infectious disease that is difficult to control and presents itself in
three clinical forms: cutaneous, mucocutaneous and visceral leishmaniasis, caused
by more than 20 species of parasites of the genus Leishmania spp., transmitted by
the insect vector, the sand fly. Current chemotherapy for leishmaniasis faces
significant limitations due to high toxicity, prolonged treatment regimens and
increased parasite resistance, highlighting the urgent need for new treatment
strategies. This study aimed to evaluate the in vitro activity of triazole derivatives
against promastigotes and amastigotes of L. amazonensis, as well as its cytotoxicity
in murine macrophages. In addition to investigate the mechanism of parasite killing.
antipromastigote activity and cytotoxicity in peritoneal macrophages were determined
by the colorimetric MTT method after 72 hours of treatment. The anti-amastigote
effect was evaluated in macrophages infected with L. amazonensis after 72 hours of
incubation, stained with Giemsa and counted by optical microscopy. The tests for
analysis of the mechanism of action were performed using different biochemical and
cellular indicators of cell death parameters, by fluorimetry and flow cytometry.
Additionally, the ultrastructure and morphology of promastigotes treated with TZDS
were analyzed by electron microscopy. The results found highlighted the importance
of triazole salts, since the neutral form did not show inhibition of parasite growth.
However, the triazole-derived salt demonstrated a promising selective index (SI =
34.28) and antileishmanial activity (IC50 = 0.13 μM and IC50 = 2.06 μM against
promastigote and amastigote forms, respectively), proving to be more active than
miltefosine, the standard drug. Regarding the TZDS mode of action, this compound
induced significant mitochondrial alterations in the parasite, characterized by an
increase in mitochondrial membrane potential (ΔΨm), elevated levels of total and
mitochondrial Reactive Oxygen Species (ROS), and accumulation of lipid bodies in
the cytoplasm. Treatment with triazole salt also produced several ultrastructural,
biochemical, and cellular alterations in the promastigotes, consistent with apoptosislike cell death, including cell shrinkage and reduction in length, as well as exposure
of phosphatidylserine in the outer leaflet of the plasma membrane and marked cell
cycle arrest, in addition to DNA fragmentation. Despite the positive MDC
(monodansylcadaverine) and the presence of membrane-bound vacuoles resembling
autophagosomal structures observed by TEM analysis, autophagy is not a
predominant process, with severe mitochondrial damage emerging as the primary
event leading to parasite death. These findings demonstrate the promising
antileishmanial potential of the triazole-derived salt, with its effect on multiple targets
in L. amazonensis cells. Furthermore, the association of the active compound with
miltefosine showed an additive effect in the treatment of macrophages infected by L.
amazonensis. Overall, these results highlight the therapeutic potential of the
evaluated salt and support further studies to evaluate its in vivo efficacy in a murine
model of cutaneous leishmaniasis.As leishmanioses são doenças infecciosas de difícil controle e se apresentam em
três formas clínicas: leishmaniose cutânea, mucocutânea e visceral, causadas por
mais de 20 espécies de parasitos do gênero Leishmania spp., sendo transmitidos
pelo inseto vetor, flebotomíneo. A quimioterapia atual para leishmaniose enfrenta
limitações significativas devido à alta toxicidade, regimes de tratamento prolongados
e aumento da resistência do parasita, destacando a necessidade urgente de novas
estratégias de tratamentos. Este estudo teve como objetivo avaliar a atividade in
vitro do sal de derivados de triazol contra promastigotas e amastigotas de L.
amazonensis, bem como sua citotoxicidade em macrófagos murinos. Além disso,
investigar o mecanismo de morte do parasito. A atividade antipromastigota e a
citotoxicidade em macrófagos peritoneais foram determinadas pelo método
colorimétrico do MTT após 72 horas de tratamento. O efeito antiamastigota foi
avaliado em macrófagos infectados com L. amazonensis após 72 horas de
incubação, corados com Giemsa e contados em microscopia óptica. Os testes para
análises do mecanismo de ação foram feitos por meio de diferentes indicadores
bioquímicos e celulares de parâmetros de morte celular, por fluorimetria e citometria
de fluxo. Adicionalmente, foram analisados a ultraestrutura e a morfologia das
promastigotas tratadas com TZDS, em microscopia eletrônica. Os resultados
encontrados ressaltaram a importância dos sais de triazóis, pois a forma neutra não
mostrou inibição do crescimento do parasita. Porém, o sal derivado de triazol
demonstrou índice seletivo promissor (SI = 34,28) e atividade antileishmania (IC50=
0,13 μM e IC50= 2,06 μM contra formas promastigotas e amastigotas,
respectivamente), provando ser mais ativo do que a miltefosina, o medicamento
padrão. Em relação ao modo de ação TZDS, este composto induziu alterações
mitocondriais significativas no parasita, caracterizadas por um aumento no potencial
de membrana mitocondrial (ΔΨm), níveis elevados de Espécies Reativas de
Oxigênio (ROS) totais e mitocondriais e acúmulo de corpos lipídicos no citoplasma.
O tratamento com sal derivado de triazol também produziu várias alterações
ultraestruturais, bioquímicas e celulares nas formas promastigotas, compatíveis com
morte celular por apoptose-like, incluindo encolhimento celular e redução no
comprimento, bem como exposição de fosfatidilserina no folheto externo da
membrana plasmática e interrupção acentuada do ciclo celular, além de
fragmentação de DNA. Apesar do MDC (monodansilcadaverina) positivo e da
presença de vacúolos ligados à membrana que se assemelham a estruturas
autofagossômicas observadas pela análise TEM, a autofagia não é um processo
predominante, com danos mitocondriais graves emergindo como o evento primário
que leva à morte do parasito. Esses achados demonstram o potencial antileishmania
promissor do sal derivado de triazol, com seu efeito em múltiplos alvos em células de
L amazonensis. Além disso, a associação do composto ativo com miltefosina
mostrou um efeito aditivo no tratamento de macrófagos infectados por L.
amazonensis. No geral, esses resultados destacam o potencial terapêutico do sal
avaliado e dão suporte a estudos adicionais para avaliar sua eficácia in vivo em um
modelo murino de leishmaniose cutânea
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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