Estresse Oxidativo como Fator Importante na Fisiopatologia da Doença de Alzheimer

Oxidative stress has been associated to play a crucial role in the pathogenesis of many diseases, including neurodegenerative diseases. Alzheimer's disease is an age-related neurodegenerative disorder, which is recognized as the most common form of dementia. In this article, the aim was to review the involvement of oxidative stress on Alzheimer's disease. Alzheimer's disease is histopathologically characterized by the presence of extracellular amyloid plaques, intracellular neurofibrillary tangles, the presence of oligomers of amyloid-? peptide and loss of synapses. Moreover, the brain and the nervous system are more prone to oxidative stress and oxidative damage influences the neurodegenerative diseases. However, increased oxidative damage, mitochondrial dysfunction, accumulation of oxidized aggregated proteins, inflammation, and defects in proteins constitute complex intertwined pathologies that lead to neuronal cell death. Mitochondrial mutations on deoxyribonucleic acid and oxidative stress contribute to aging, affecting different cell signaling systems, as well as the connectivity and neuronal cell death may lead to the largest risk factor for neurodegenerative diseases such as Alzheimer's Disease.O estresse oxidativo tem sido apontado como um ator importante na patogênese de várias doenças, incluindo doenças neurodegenerativas. A Doença de Alzheimer é uma desordem neurodegenerativa relacionada à idade, que é reconhecida como a forma mais comum de demência. Neste artigo, o objetivo foi revisar a participação de estresse oxidativo na Doença de Alzheimer. A Doença de Alzheimer é caracterizada histopatologicamente pela presença de placas amilóides extracelulares, emaranhados neurofibrilares intracelulares, a presença de oligômeros do peptídeo -amiloide e a perda de sinapse. Além disso, o cérebro e o sistema nervoso são mais propensos ao estresse oxidativo e o dano oxidativo influencia nas doenças neurodegenerativas. Entretanto, o aumento do dano oxidativo, disfunção mitocondrial, acúmulo de agregados de proteínas oxidadas, inflamação e defeitos nas proteínas constituem patologias complexas interligadas que levam à morte celular de neurônios. Mutações no ácido desoxirribonucleico mitocondrial e estresse oxidativo contribuem para o envelhecimento, afetando diferentes sistemas de sinalização da célula, bem como conectividade neuronal, podendo levar à morte celular, sendo o maior fator de risco para doenças neurodegenerativas, como na Doença de Alzheimer

Dengue Infection Increases the Locomotor Activity of Aedes aegypti Females

BACKGROUND: Aedes aegypti is the main vector of the virus causing Dengue fever, a disease that has increased dramatically in importance in recent decades, affecting many tropical and sub-tropical areas of the globe. It is known that viruses and other parasites can potentially alter vector behavior. We investigated whether infection with Dengue virus modifies the behavior of Aedes aegypti females with respect to their activity level. METHODS/PRINCIPAL FINDINGS: We carried out intrathoracic Dengue 2 virus (DENV-2) infections in Aedes aegypti females and recorded their locomotor activity behavior. We observed an increase of up to ∼50% in the activity of infected mosquitoes compared to the uninfected controls. CONCLUSIONS: Dengue infection alters mosquito locomotor activity behavior. We speculate that the higher levels of activity observed in infected Aedes aegypti females might involve the circadian clock. Further studies are needed to assess whether this behavioral change could have implications for the dynamics of Dengue virus transmission

The brief methylprednisolone administration is crucial to mitigate cardiac dysfunction after myocardial infarction

Acute myocardial infarction (AMI) is one of the major causes of heart failure and mortality. Glucocorticoids administration post-infarction has long been proposed, but it has shown conflicting results so far. This controversy may be associated with the glucocorticoid type and the period when it is administered. To elucidate these, the present aims to evaluate if the brief methylprednisolone acetate administration is determinant for heart adaptation after AMI. Male Wistar rats were divided into 3 groups: sham-operated (SHAM); infarcted (AMI); infarcted treated with methylprednisolone acetate (AMI+M). Immediately after surgery, the AMI+M group received a single dose of methylprednisolone acetate (40 mg/kg i.m.). After 56 days, the cardiac function was assessed and lungs, liver and heart were collected to determine rates of hypertrophy and congestion. Heart was used for oxidative stress and metalloproteinase activity analyses. Methylprednisolone acetate attenuated matrix metalloproteinase-2 activity, cardiac dilatation, and prevented the onset of pulmonary congestion, as well as avoided cardiac hypertrophy. Our data indicate that administration of methylprednisolone acetate shortly after AMI may be a therapeutic alternative for attenuation of detrimental ventricular remodeling

Decreased PGC1-α levels and increased apoptotic protein signaling are associated with the maladaptive cardiac hypertrophy in hyperthyroidism

Hyperthyroidism can lead to the activation of proteins which are associated with inflammation, apoptosis, hypertrophy, and heart failure. This study aimed to explore the inflammatory and apoptotic proteins involved in the hyperthyroidism-induced cardiac hypertrophy establishment. Male Wistar rats were divided into control and hyperthyroid (12 mg/L L-thyroxine, in drinking water for 28 days) groups. The expression of inflammatory and apoptotic signaling proteins was quantified in the left ventricle by Western blot. Hyperthyroidism was confirmed by evaluation of T3 and T4 levels, as well as cardiac hypertrophy development. There was no change in the expression of HSP70, HIF1-a, TNF-a, MyD88, p-NFjB, NFjB, p-p38, and p38. Reduced expression of p53 and PGC1-a was associated with increased TLR4 and decreased IL-10 expression. Decreased Bcl-2 expression and increased Bax/Bcl-2 ratio were also observed. The results suggest that reduced PGC1-a and IL-10, and elevated TLR4 proteins expression could be involved with the diminished mitochondrial biogenesis and anti-inflammatory response, as well as cell death signaling, in the establishment of hyperthyroidism-induced maladaptive cardiac hypertrophy

Pterostilbene reduces experimental myocardial infarction-induced oxidative stress in lung and right ventricle

Fundamento: O pterostilbeno (PS), um composto polifenólico natural e antioxidante, surge como uma intervenção promissora para minimizar danos do infarto agudo do miocárdio (IAM). Objetivo: Este estudo teve como objetivo avaliar o desempenho do PS na promoção da homeostase redox nos pulmões e no ventrículo direito (VD) de animais infartados. Métodos: Ratos Wistar machos (60 dias de idade) foram randomizados em três grupos: SHAM, IAM (infarto) e IAM+PS (IAM + pterostilbeno). Sete dias após o procedimento de IAM, os ratos foram tratados com PS (100 mg/kg/dia) por gavagem por oito dias. Os animais foram depois sacrificados e os pulmões e VD foram coletados para análise do balanço redox (diferenças foram consideradas significativas quando p<0,05). Resultados: Nossos resultados mostram que o IAM desencadeia a interrupção redox no VD e nos pulmões, o que pode contribuir para danos induzido pelo IAM nesses órgãos. Consistentemente, o PS mitigou o estresse oxidativo e restaurou as defesas antioxidantes (Glutationa – GSH nos pulmões: SHAM = 0,79 ± 0,07; IAM = 0,67 ± 0,05; IAM + PS = 0,86 ± 0,14; p<0,05), indicando seu papel protetor neste cenário. Conclusão: Nosso trabalho evidencia o potencial do uso de PS como abordagem terapêutica adjuvante após IAM para proteção dos tecidos pulmonares e cardíacos direitos.Background: Pterostilbene (PS), a natural and antioxidant polyphenolic compound emerges as a promising intervention in improving the myocardial infarction (MI) damages. Objetives: This study aimed to evaluate PS actions in promoting redox homeostasis in lungs and right ventricle (RV) of infarcted animals. Methods: Male Wistar rats (60 day-old) were randomized into three groups: SHAM, MI (infarcted), and MI+PS (MI+pterostilbene). Seven days after MI procedure, rats were treated with PS (100 mg/kg/day) via gavage for eight days. Animals were euthanized and the lungs and RV were harvested for analyses of redox balance (Differences were considered significant when p<0.05). Results: Our results show that MI triggers a redox disruption scenario in RV and lungs, which can contribute to MI-induced damage on these organs. Consistently, PS mitigated oxidative stress and restored antioxidant defenses (GSH in lungs: SHAM= 0.79±0.07; MI=0.67±0.05; MI+PS=0.86±0.14; p<0.05), indicating its protective role in this scenario. Conclusions: Our work evidences the PS potential use as an adjuvant therapeutic approach after MI focusing on protecting pulmonary and right-sided heart tissues

Incipient parallel evolution of SARS-CoV-2 Deltacron variant in South Brazil

With the coexistence of multiple lineages and increased international travel, recombination and gene flow are likely to become increasingly important in the adaptive evolution of SARS-CoV-2. These processes could result in genetic introgression and the incipient parallel evolution of multiple recombinant lineages. However, identifying recombinant lineages is challenging, and the true extent of recombinant evolution in SARS-CoV-2 may be underestimated. This study describes the first SARS-CoV-2 Deltacron recombinant case identified in Brazil. We demonstrate that the recombination breakpoint is at the beginning of the Spike gene. The 5′ genome portion (circa 22 kb) resembles the AY.101 (Delta), and the 3′ genome portion (circa 8 kb nucleotides) is most similar to the BA.1.1 (Omicron). Furthermore, evolutionary genomic analyses indicate that the new strain emerged after a single recombination event between lineages of diverse geographical locations in December 2021 in South Brazil. This Deltacron, AYBA-RS, is one of the dozens of recombinants described in 2022. The submission of only four sequences in the GISAID database suggests that this lineage had a minor epidemiological impact. However, the recent emergence of this and other Deltacron recombinant lineages (XD, XF, and XS) suggests that gene flow and recombination may play an increasingly important role in the COVID-19 pandemic. We explain the evolutionary and population genetic theory that supports this assertion, concluding that this stresses the need for continued genomic surveillance. This monitoring is vital for countries where multiple variants are present, as well as for countries that receive significant inbound international travel

estudos artísticos

A proposta da Revista Gama associa-se ao projeto do Congresso CSO — Criadores Sobre outras Obras — mas com uma opção editorial específica, de valorizar as obras merecedoras de uma revisão ao seu tempo, à sua génese, ao seu contexto. O estudo destes contextos permite um olhar integrador sobre a cultura. A mudança é profunda. Hoje, se já não se trata de mudar o mundo, restará ocupar os espaços desgovernados: é este o perigo na “Sociedade sem relato” (Canclini). Talvez a pesquisa que se impõe seja aquela que consegue estabelecer novas relações entre os referentes e agentes culturais, sem ambicionar revelar tramas ocultas, mas propondo linhas condutoras que permitam uma leitura do mundo no desordenamento cultural. É desde esse ponto que “a arte pode continuar a nos dar, nesta desencantada mudança de século, o mínimo de utopia sem a qual o progresso material perde o sentido da emancipação e se transforma na pior das perversões” (Martín-Barbero). Alguns dos 15 artigos apresentados neste número 8 da revista Gama devolvem-nos conhecimentos sobre propostas artísticas menos conhecidas no decorrer das décadas. Artistas retêm na sua memória a obra de alguns dos seus companheiros de trabalho: o seu olhar é privilegiado para conhecer o fazer artístico pelo lado de dentro, testemunhar o entretecer das tramas onde se elaboram os discursos, intervenções, que constroem a cultura. Lança-se o olhar, procura-se entre os iguais estudam-se as falas. As coisas precisam de voltar a ser pensadas.info:eu-repo/semantics/publishedVersio