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OBJECTIVE: This double-blind, randomised, placebo-controlled, two-part study assessed the impact of GSK2981710, a medium-chain triglyceride (MCT) that liberates ketone bodies, on cognitive function, safety, and tolerability in healthy older adults. METHODS: Part 1 was a four-period dose-selection study (n = 8 complete). Part 2 was a two-period crossover study (n = 80 complete) assessing the acute (Day 1) and prolonged (Day 15) effects of GSK2981710 on cognition and memory-related neuronal activity. Safety and tolerability of MCT supplementation were monitored in both parts of the study. RESULTS: The most common adverse event was diarrhoea (100% and 75% of participants in Parts 1 and 2, respectively). Most adverse events were mild to moderate, and 11% participants were withdrawn due to one or more adverse events. Although GSK2981710 (30 g/day) resulted in increased peak plasma ß-hydroxybutyrate (BHB) concentrations, no significant improvements in cognitive function or memory-related neuronal activity were observed. CONCLUSION: Over a duration of 14 days, increasing plasma BHB levels with daily administration of GSK2981710 had no effects on neuronal activity or cognitive function. This result indicates that modulating plasma ketone levels with GSK2981710 may be ineffective in improving cognitive function in healthy older adults, or the lack of observed effect could be related to several factors including study population, plasma BHB concentrations, MCT composition, or treatment duration.
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Cognição/efeitos dos fármacos , Triglicerídeos/farmacologia , Ácido 3-Hidroxibutírico/sangue , Idoso , Idoso de 80 Anos ou mais , Estudos Cross-Over , Método Duplo-Cego , Eletroencefalografia/efeitos dos fármacos , Feminino , Voluntários Saudáveis , Humanos , Masculino , Pessoa de Meia-Idade , Neurônios/fisiologia , Testes Neuropsicológicos , Triglicerídeos/efeitos adversosRESUMO
BACKGROUND: The characteristics and natural history of GOLD B COPD patients are not well described. The clinical characteristics and natural history of GOLD B patients over 1 year in a multicentre cohort of COPD patients in the COPDMAP study were assessed. We aimed to identify the subgroup of patients who progressed to GOLD D (unstable GOLD B patients) and identify characteristics associated with progression. METHODS: Three hundred seventy COPD patients were assessed at baseline and 12 months thereafter. Demographics, lung function, health status, 6 min walk tests and levels of systemic inflammation were assessed. Students t tests and Mann Whitney-U tests were used. RESULTS: One hundred seven (28.9%) of patients were categorised as GOLD B at baseline. These GOLD B patients had similar FEV1 to GOLD A patients (66% predicted). More GOLD B patients were current smokers (p = 0.031), had chronic bronchitis (p = 0.0003) and cardiovascular comorbidities (p = 0.019) compared to GOLD A. At 12 months, 25.3% of GOLD B patients progressed to GOLD D. These patients who progressed (unstable patients) had worse health status and symptoms (SGRQ-C Total, 50.0 v 41.1, p = 0.019 and CAT, 21.0 v 14.0, p = 0.006) and lower FEV1 (60% v 69% p = 0.014) at baseline compared to stable patients who remained in GOLD B. CONCLUSIONS: Unstable GOLD B patients who progressed to GOLD D had a higher level of symptoms at baseline. A high symptom burden may predict an increased likelihood of disease progression in GOLD B patients.
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Progressão da Doença , Doença Pulmonar Obstrutiva Crônica/classificação , Doença Pulmonar Obstrutiva Crônica/fisiopatologia , Idoso , Comorbidade , Feminino , Volume Expiratório Forçado , Nível de Saúde , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Índice de Gravidade de Doença , Reino UnidoRESUMO
During Ebola virus (EBOV) infection a significant amount of surface glycoprotein GP is shed from infected cells in a soluble form due to cleavage by cellular metalloprotease TACE. Shed GP and non-structural secreted glycoprotein sGP, both expressed from the same GP gene, have been detected in the blood of human patients and experimentally infected animals. In this study we demonstrate that shed GP could play a particular role during EBOV infection. In effect it binds and activates non-infected dendritic cells and macrophages inducing the secretion of pro- and anti-inflammatory cytokines (TNFα, IL1ß, IL6, IL8, IL12p40, and IL1-RA, IL10). Activation of these cells by shed GP correlates with the increase in surface expression of co-stimulatory molecules CD40, CD80, CD83 and CD86. Contrary to shed GP, secreted sGP activates neither DC nor macrophages while it could bind DCs. In this study, we show that shed GP activity is likely mediated through cellular toll-like receptor 4 (TLR4) and is dependent on GP glycosylation. Treatment of cells with anti-TLR4 antibody completely abolishes shed GP-induced activation of cells. We also demonstrate that shed GP activity is negated upon addition of mannose-binding sera lectin MBL, a molecule known to interact with sugar arrays present on the surface of different microorganisms. Furthermore, we highlight the ability of shed GP to affect endothelial cell function both directly and indirectly, demonstrating the interplay between shed GP, systemic cytokine release and increased vascular permeability. In conclusion, shed GP released from virus-infected cells could activate non-infected DCs and macrophages causing the massive release of pro- and anti-inflammatory cytokines and effect vascular permeability. These activities could be at the heart of the excessive and dysregulated inflammatory host reactions to infection and thus contribute to high virus pathogenicity.
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Células Dendríticas/imunologia , Ebolavirus/imunologia , Doença pelo Vírus Ebola/imunologia , Células Endoteliais da Veia Umbilical Humana/imunologia , Macrófagos/imunologia , Glicoproteínas de Membrana/imunologia , Proteínas Virais/imunologia , Animais , Antígenos CD/imunologia , Citocinas/imunologia , Células Dendríticas/patologia , Células Dendríticas/virologia , Cobaias , Células Endoteliais da Veia Umbilical Humana/patologia , Células Endoteliais da Veia Umbilical Humana/virologia , Humanos , Macrófagos/patologia , Macrófagos/virologia , Receptor 4 Toll-Like/imunologiaRESUMO
Synthesis of Ebola virus (EBOV) surface glycoprotein (GP) is dependent on transcriptional RNA editing. Northern blot analysis of EBOV-infected cells using GP-gene-specific probes reveals that, in addition to full-length GP messenger RNAs (mRNAs), a shorter RNA is also synthesized, representing >40% of the total amount of GP mRNA. Sequence analysis demonstrates that this RNA is a truncated version of the full-length GP mRNA that is polyadenylated at the editing site and thus lacks a stop codon. An absence of detectable levels of protein synthesis in cellulo is consistent with the existence of tight regulation of the translation of such mRNA. However, nonstop GP mRNA was shown to be only slightly less stable than the same mRNA containing a stop codon, against the general belief in nonstop decay mechanisms aimed at detecting and destroying mRNAs lacking a stop codon. In conclusion, we demonstrate that the editing site indeed serves as a cryptic transcription termination/polyadenylation site, which rarely also functions to edit GP mRNA for expression of surface GP. This new data suggest that the downregulation of surface GP expression is even more dramatic than previously thought, reinforcing the importance of the GP gene editing site for EBOV replication and pathogenicity.
Assuntos
Ebolavirus/genética , Glicoproteínas/genética , Poliadenilação/genética , Edição de RNA/genética , Proteínas Virais/genética , Animais , Linhagem Celular , Chlorocebus aethiops , Códon de Terminação/genética , Regulação para Baixo/genética , Células HEK293 , Humanos , RNA Mensageiro/genética , Células VeroRESUMO
The surface glycoprotein (GP) is responsible for Ebola virus (EBOV) attachment and membrane fusion during virus entry. Surface expression of highly glycosylated GP causes marked cytotoxicity via masking of a wide range of cellular surface molecules, including integrins. Considerable amounts of surface GP are shed from virus-infected cells in a soluble truncated form by tumor necrosis factor α-converting enzyme. In this study, the role of GP shedding was investigated using a reverse genetics approach by comparing recombinant viruses possessing amino acid substitutions at the GP shedding site. Virus with an L635V substitution showed a substantial decrease in shedding, whereas a D637V substitution resulted in a striking increase in the release of shed GP. Variations in shedding efficacy correlated with observed differences in the amounts of shed GP in the medium, GP present in virus-infected cells, and GP present on virions. An increase in shedding appeared to be associated with a reduction in viral cytotoxicity, and, vice versa, the virus that shed less was more cytotoxic. An increase in shedding also resulted in a reduction in viral infectivity, whereas a decrease in shedding efficacy enhanced viral growth characteristics in vitro. Differences in shedding efficacy and, as a result, differences in the amount of mature GP available for incorporation into budding virions did not equate to differences in overall release of viral particles. Likewise, data suggest that the resulting differences in the amount of mature GP on the cell surface led to variations in the GP content of released particles and, as a consequence, in infectivity. In conclusion, fine-tuning of the levels of EBOV GP expressed at the surface of virus-infected cells via GP shedding plays an important role in EBOV replication by orchestrating the balance between optimal virion GP content and cytotoxicity caused by GP.
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Ebolavirus/metabolismo , Ebolavirus/patogenicidade , Doença pelo Vírus Ebola/virologia , Glicoproteínas de Membrana/metabolismo , Substituição de Aminoácidos/genética , Animais , Linhagem Celular , Chlorocebus aethiops , Ebolavirus/genética , Glicoproteínas de Membrana/genética , Células Vero , Proteínas Virais/genética , Proteínas Virais/metabolismo , Vírion/genética , Vírion/metabolismo , Vírion/patogenicidade , Virulência/genética , Internalização do Vírus , Replicação Viral/genéticaRESUMO
The brain-derived neurotropic factor (BDNF) Val66Met polymorphism has been associated with abnormalities of synaptic plasticity in animal models, and abnormalities in motor cortical plasticity have also been described in humans using transcranial direct current stimulation. No study has yet been done on plasticity in non-motor regions, and the effect of two Met alleles (i.e. 'Met dose') is not well understood. We studied the effect of the BDNF Val66Met polymorphism on the after-effects of transcranial direct current stimulation and tetanic auditory stimulation in 65 subjects (23; Val66Val, 22; Val66Met and 20; Met66Met genotypes). In the first session, motor evoked potentials (MEP) were recorded under stereotaxic guidance for 90 min after 9 min of anodal transcranial direct current stimulation (TDCS). In the second session, auditory-evoked potentials (AEP) were recorded before and after 2 min of auditory 13 Hz tetanic stimulation. There was a difference in MEP facilitation post-TDCS comparing Met carriers with non-Met carriers, with Met carriers having a modest late facilitation at 30-90 min. There was no difference in responses between Val66Met genotype and Met66Met genotype subjects. Tetanic auditory stimulation also produced late facilitation of N1-P2 AEP at 25 min, but there was no apparent effect of genetic status. This study indicates that Met66Met carriers behave like Val66Met carriers for TDCS-induced plasticity, and produce a late facilitation of MEPs. Auditory cortical plasticity was not affected by the BDNF Val66Met polymorphism. This study sheds light on the differences between auditory and motor cortical plasticity and the role of the BDNF Val66Met polymorphism.
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Córtex Auditivo/fisiologia , Percepção Auditiva , Fator Neurotrófico Derivado do Encéfalo/genética , Córtex Motor/fisiologia , Plasticidade Neuronal , Polimorfismo de Nucleotídeo Único , Estimulação Acústica , Adulto , Alelos , Percepção Auditiva/genética , Estimulação Elétrica , Potenciais Evocados Auditivos/genética , Potencial Evocado Motor/genética , Feminino , Técnicas de Genotipagem , Humanos , Masculino , Pessoa de Meia-Idade , Plasticidade Neuronal/genética , Estimulação Magnética Transcraniana , Adulto JovemRESUMO
Tyrosinases (TYRs; EC 1.14.18.1) catalyze two sequential oxidative reactions of the melanin biosynthesis pathway and play an important role in mammalian pigmentation and enzymatic browning of fruit and vegetables. Inhibition of TYR activity is therefore an attractive target for new drugs and/or food ingredients. In addition, increasing evidence suggests that TYR regulation could be a novel target for treatments of cancer and Parkinson's disease. Biomasses, notably industrial byproducts and biowaste, are good sustainable sources of phytochemicals that may be valorized into bioactive compounds including TYR inhibitors. This review presents potential applications of biomass-derived polyphenols targeting TYR inhibition. Insights into structure-activity relationships of several polyphenols and their glycosides are highlighted. Finally, some remarks and perspectives on research into new TYR inhibitors from biomass waste are provided.
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Monofenol Mono-Oxigenase , Polifenóis , Animais , Biomassa , Polifenóis/farmacologia , Extratos Vegetais , Compostos Fitoquímicos , Mamíferos/metabolismoRESUMO
Lignocellulosic biomass has a promising role in a circular bioeconomy and may be used to produce valuable molecules for green chemistry. Lignocellulosic biomass, such as food waste, agricultural waste, wood, paper or cardboard, corresponded to 15.7% of all waste produced in Europe in 2020, and has a high potential as a secondary raw material for industrial processes. This review first presents industrial lignocellulosic waste sources, in terms of their composition, quantities and types of lignocellulosic residues. Secondly, the possible high added-value chemicals obtained from transformation of lignocellulosic waste are detailed, as well as their potential for applications in the food industry, biomedical, energy or chemistry sectors, including as sources of polyphenols, enzymes, bioplastic precursors or biofuels. In a third part, various available transformation treatments, such as physical treatments with ultrasound or heat, chemical treatments with acids or bases, and biological treatments with enzymes or microorganisms, are presented. The last part discusses the perspectives of the use of lignocellulosic waste and the fact that decreasing the cost of transformation is one of the major issues for improving the use of lignocellulosic biomass in a circular economy and green chemistry approach, since it is currently often more expensive than petroleum-based counterparts.
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Biomassa , Resíduos Industriais , Lignina , Lignina/química , Resíduos Industriais/análise , Gerenciamento de Resíduos/métodos , Biocombustíveis/análise , Eliminação de Resíduos/métodosRESUMO
Episodic memory deficits are a core feature of neurodegenerative disorders. Muscarinic M(1) receptors play a critical role in modulating learning and memory and are highly expressed in the hippocampus. We examined the effect of GSK1034702, a potent M(1) receptor allosteric agonist, on cognitive function, and in particular episodic memory, in healthy smokers using the nicotine abstinence model of cognitive dysfunction. The study utilized a randomized, double-blind, placebo-controlled, cross-over design in which 20 male nicotine abstained smokers were tested following single doses of placebo, 4 and 8 mg GSK1034702. Compared to the baseline (nicotine on-state), nicotine abstinence showed statistical significance in reducing immediate (p=0.019) and delayed (p=0.02) recall. GSK1034702 (8 mg) significantly attenuated (i.e. improved) immediate recall (p=0.014) but not delayed recall. None of the other cognitive domains was modulated by either nicotine abstinence or GSK1034702. These findings suggest that stimulating M(1) receptor mediated neurotransmission in humans with GSK1034702 improves memory encoding potentially by modulating hippocampal function. Hence, selective M(1) receptor allosteric agonists may have therapeutic benefits in disorders of impaired learning including Alzheimer's disease.
Assuntos
Comportamento Aditivo/psicologia , Benzimidazóis/uso terapêutico , Transtornos Cognitivos/psicologia , Memória Episódica , Receptor Muscarínico M1/agonistas , Abandono do Hábito de Fumar/psicologia , Adulto , Regulação Alostérica/efeitos dos fármacos , Regulação Alostérica/fisiologia , Comportamento Aditivo/tratamento farmacológico , Benzimidazóis/farmacologia , Transtornos Cognitivos/tratamento farmacológico , Estudos Cross-Over , Método Duplo-Cego , Humanos , Masculino , Pessoa de Meia-Idade , Nicotina , Receptor Muscarínico M1/fisiologia , Fumar/psicologia , Adulto JovemRESUMO
About 0.8 million people die because of hepatitis B virus (HBV) infection each year. In around 5% of infected adults, the immune system is ineffective in countering HBV infection, leading to chronic hepatitis B (CHB). CHB is associated with hepatocellular carcinoma, which can lead to patient death. Unfortunately, although current treatments against CHB allow control of HBV infection, they are unable to achieve complete eradication of the virus. Cytokines of the IFN family represent part of the innate immune system and are key players in virus elimination. IFN secretion induces the expression of interferon stimulated genes, producing proteins that have antiviral properties and that are essential to cell-autonomous immunity. IFN-α is commonly used as a therapeutic approach for CHB. In addition, IFN-γ has been identified as the main IFN family member responsible for HBV eradication during acute infection. In this review, we summarize the key evidence gained from cellular or animal models of HBV replication or infection concerning the potential anti-HBV roles of IFN-γ with a particular focus on some IFN-γ-inducible genes.
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Emerging infectious diseases of zoonotic origin are an ever-increasing public health risk and economic burden. The factors that determine if and when an animal virus is able to spill over into the human population with sufficient success to achieve ongoing transmission in humans are complex and dynamic. We are currently unable to fully predict which pathogens may appear in humans, where and with what impact. In this review, we highlight current knowledge of the key host-pathogen interactions known to influence zoonotic spillover potential and transmission in humans, with a particular focus on two important human viruses of zoonotic origin, the Nipah virus and the Ebola virus. Namely, key factors determining spillover potential include cellular and tissue tropism, as well as the virulence and pathogenic characteristics of the pathogen and the capacity of the pathogen to adapt and evolve within a novel host environment. We also detail our emerging understanding of the importance of steric hindrance of host cell factors by viral proteins using a "flytrap"-type mechanism of protein amyloidogenesis that could be crucial in developing future antiviral therapies against emerging pathogens. Finally, we discuss strategies to prepare for and to reduce the frequency of zoonotic spillover occurrences in order to minimize the risk of new outbreaks.
Assuntos
Doenças Transmissíveis Emergentes , Vírus , Animais , Humanos , Zoonoses , Interações Hospedeiro-Patógeno , Doenças Transmissíveis Emergentes/epidemiologia , Saúde PúblicaRESUMO
Correlates of protection (CoP) are biological parameters that predict a certain level of protection against an infectious disease. Well-established correlates of protection facilitate the development and licensing of vaccines by assessing protective efficacy without the need to expose clinical trial participants to the infectious agent against which the vaccine aims to protect. Despite the fact that viruses have many features in common, correlates of protection can vary considerably amongst the same virus family and even amongst a same virus depending on the infection phase that is under consideration. Moreover, the complex interplay between the various immune cell populations that interact during infection and the high degree of genetic variation of certain pathogens, renders the identification of immune correlates of protection difficult. Some emerging and re-emerging viruses of high consequence for public health such as SARS-CoV-2, Nipah virus (NiV) and Ebola virus (EBOV) are especially challenging with regards to the identification of CoP since these pathogens have been shown to dysregulate the immune response during infection. Whereas, virus neutralising antibodies and polyfunctional T-cell responses have been shown to correlate with certain levels of protection against SARS-CoV-2, EBOV and NiV, other effector mechanisms of immunity play important roles in shaping the immune response against these pathogens, which in turn might serve as alternative correlates of protection. This review describes the different components of the adaptive and innate immune system that are activated during SARS-CoV-2, EBOV and NiV infections and that may contribute to protection and virus clearance. Overall, we highlight the immune signatures that are associated with protection against these pathogens in humans and could be used as CoP.
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COVID-19 , Ebolavirus , Doença pelo Vírus Ebola , Infecções por Henipavirus , Humanos , Infecções por Henipavirus/prevenção & controle , SARS-CoV-2RESUMO
Over the last decade, the emergence of several zoonotic viruses has demonstrated that previously unknown or neglected pathogens have the potential to cause epidemics and therefore to pose a threat to global public health. Even more concerning are the estimated 1.7 million still-undiscovered viruses present in the natural environment or 'global virome', with many of these as-yet uncharacterized viruses predicted to be pathogenic for humans. Thus, in order to mitigate disease emergence and prevent future pandemics, it is crucial to identify the global extent of viral threats to which humans may become exposed. This requires cataloguing the viruses that exist in the environment within their various and diverse host species, and also understanding the viral, host, and environmental factors that dictate the circumstances that result in viral spillover into humans. We also address here which strategies can be implemented as countermeasure initiatives to reduce the risk of emergence of new diseases.
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Pandemias , Vírus , Humanos , Viroma , Vírus/genética , Meio Ambiente , Especificidade de HospedeiroRESUMO
In Mali, hepatocellular carcinoma (HCC) is the third and sixth most common cancer in men and women, respectively. Mali comprises several distinct climato-ecological zones. Most studies to date have been conducted in the sub-Sahelian zone of southern Mali, including the capital city Bamako. In this part of the country, the main risk factors for HCC are chronic hepatitis B virus (HBV) carriage and dietary exposure to aflatoxins, a well-known hepatocarcinogen. Data are scarce for other ecological zones, but our preliminary data from 721 blood donors in the area of Timbuktu, presented in this study, suggest that chronic HBV carriage is also endemic in the northern Saharan zone of Mali. For further study, 29 healthy HBV chronic carrier volunteers were recruited from the blood transfusion center in Timbuktu. Successful viral genotyping in 20 volunteers revealed HBV genotype E in 13 cases and D in 7 cases, suggesting that this geographical and anthropological transition zone may also represent a transition zone between HBV genotypes that dominate sub-Saharan and northern Africa, respectively. Sequencing of circulating cell-free plasma DNA (cfDNA) from donors did not reveal the presence of the TP53 R249S mutation in these donors, a marker of dietary exposure to aflatoxins in sub-Saharan Africa. These results suggest that the geo-epidemiological distribution of the risk factors for HCC is not uniform across Mali, but is dependent upon climatic, socioeconomic and anthropological factors that might have an impact on patterns of chronic liver disease and cancer.
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Nipah henipavirus (NiV) and Hendra henipavirus (HeV) are zoonotic emerging paramyxoviruses causing severe disease outbreaks in humans and livestock, mostly in Australia, India, Malaysia, Singapore and Bangladesh. Both are bat-borne viruses and in humans, their mortality rates can reach 60% in the case of HeV and 92% for NiV, thus being two of the deadliest viruses known for humans. Several factors, including a large cellular tropism and a wide zoonotic potential, con-tribute to their high pathogenicity. This review provides an overview of HeV and NiV pathogenicity mechanisms and provides a summary of their interactions with the immune systems of their different host species, including their natural hosts bats, spillover-hosts pigs, horses, and humans, as well as in experimental animal models. A better understanding of the interactions between henipaviruses and their hosts could facilitate the development of new therapeutic strategies and vaccine measures against these re-emerging viruses.
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Quirópteros , Vírus Hendra , Infecções por Henipavirus , Vírus Nipah , Animais , Infecções por Henipavirus/epidemiologia , Cavalos , Evasão da Resposta Imune , Modelos Animais , SuínosRESUMO
Nipah virus (NiV) is a zoonotic paramyxovirus with a fatality rate of up to 92% in humans. While several pathogenic mechanisms used by NiV to counteract host immune defense responses have been described, all of the processes that take place in cells during infection are not fully characterized. Here, we describe the formation of ordered intracellular structures during NiV infection. We observed that these structures are formed specifically during NiV infection, but not with other viruses from the same Mononegavirales order (namely Ebola virus) or from other orders such as Bunyavirales (Junín virus). We also determined the kinetics of the appearance of these structures and their cellular localization at the cellular periphery. Finally, we confirmed the presence of these NiV-specific ordered structures using structured illumination microscopy (SIM), as well as their localization by transmission electron microscopy (TEM), scanning electron microscopy (SEM), and correlative light and electron microscopy (CLEM). Herein, we describe a cytopathogenic mechanism that provides a new insight into NiV biology. These newly described ordered structures could provide a target for novel antiviral approaches.
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Ebolavirus , Infecções por Henipavirus , Vírus Nipah , Paramyxovirinae , Antivirais , Humanos , Vírus Nipah/fisiologiaRESUMO
Nipah virus (NiV) is an emerging zoonotic paramyxovirus that causes severe disease in humans and livestock. Due to its high pathogenicity in humans and the lack of available vaccines and therapeutics, NiV needs to be handled in biosafety level 4 (BSL-4) laboratories. Safe inactivation of samples containing NiV is thus necessary to allow further processing in lower containment areas. To date, there is only limited information available on NiV inactivation methods validated by BSL-4 facilities that can be used as a reference. Here, we compare some of the most common inactivation methods in order to evaluate their efficacy at inactivating NiV in infected cells, supernatants and organs. Thus, several physical and chemical inactivation methods, and combinations thereof, were assessed. Viral replication was monitored for 3 weeks and NiV presence was assessed by RT-qPCR, plaque assay and indirect immunofluorescence. A total of nineteen methods were shown to reduce NiV infectious particles in cells, supernatants and organs to undetectable levels. Therefore, we provide a list of methods for the safe and efficient inactivation of NiV.
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Infecções por Henipavirus , Vírus Nipah , Humanos , Vírus Nipah/fisiologia , Replicação ViralRESUMO
Noxious stimuli in the esophagus cause pain that is referred to the anterior chest wall because of convergence of visceral and somatic afferents within the spinal cord. We sought to characterize the neurophysiological responses of these convergent spinal pain pathways in humans by studying 12 healthy subjects over three visits (V1, V2, and V3). Esophageal pain thresholds (Eso-PT) were assessed by electrical stimulation and anterior chest wall pain thresholds (ACW-PT) by use of a contact heat thermode. Esophageal evoked potentials (EEP) were recorded from the vertex following 200 electrical stimuli, and anterior chest wall evoked potentials (ACWEP) were recorded following 40 heat pulses. The fear of pain questionnaire (FPQ) was administered on V1. Statistical data are shown as point estimates of difference +/- 95% confidence interval. Pain thresholds increased between V1 and V3 [Eso-PT: V1-V3 = -17.9 mA (-27.9, -7.9) P < 0.001; ACW-PT: V1-V3 = -3.38 degrees C (-5.33, -1.42) P = 0.001]. The morphology of cortical responses from both sites was consistent and equivalent [P1, N1, P2, N2 complex, where P1 and P2 are is the first and second positive (downward) components of the CEP waveform, respectively, and N1 and N2 are the first and second negative (upward) components, respectively], indicating activation of similar cortical networks. For EEP, N1 and P2 latencies decreased between V1 and V3 [N1: V1-V3 = 13.7 (1.8, 25.4) P = 0.02; P2: V1-V3 = 32.5 (11.7, 53.2) P = 0.003], whereas amplitudes did not differ. For ACWEP, P2 latency increased between V1 and V3 [-35.9 (-60, -11.8) P = 0.005] and amplitudes decreased [P1-N1: V1-V3 = 5.4 (2.4, 8.4) P = 0.01; P2-N2: 6.8 (3.4, 10.3) P < 0.001]. The mean P1 latency of EEP over three visits was 126.6 ms and that of ACWEP was 101.6 ms, reflecting afferent transmission via Adelta fibers. There was a significant negative correlation between FPQ scores and Eso-PT on V1 (r = -0.57, P = 0.05). These data provide the first neurophysiological evidence of convergent esophageal and somatic pain pathways in humans.
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Esôfago/inervação , Potenciais Somatossensoriais Evocados/fisiologia , Dor Referida/fisiopatologia , Medula Espinal/fisiologia , Parede Torácica/inervação , Fibras Aferentes Viscerais/fisiologia , Adulto , Esôfago/fisiologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Condução Nervosa/fisiologia , Nociceptores/fisiologia , Medição da Dor , Limiar da Dor/fisiologia , Tempo de Reação/fisiologia , Parede Torácica/fisiologiaRESUMO
Background: Lung clearance index (LCI), derived from multiple-breath washout (MBW), is a well-established assessment of ventilation inhomogeneity in cystic fibrosis but has not been widely applied in other conditions characterized by heterogeneous airways disease, such as COPD. The aim of this study was to evaluate the sensitivity, repeatability, and practicality of LCI in patients with COPD. Methods: Fifty-four COPD patients completed MBW using nitrogen as the washout tracer gas (MBWN2, measured using an Exhalyzer™ device), spirometry, and plethysmography. Twenty patients repeated MBWN2, MBWSF6 (using a separate Innocor™ gas analyzer to measure washout of the exogenous trace sulphur hexafluoride), and spirometry at a second visit ≥24 hours later. Results: Mean (SD) COPD LCI measured by nitrogen washout (LCIN2) was 12.1 (2.2); mean (SD) LCI Z-score 5.8 (2.0). LCIN2 increased across Global Initiative for Obstructive Lung Disease stages 1 to 3 and was abnormal (Z-score >1.65) in all COPD patients, including those with forced expiratory volume in 1 second (FEV1) ≥80% predicted. LCI was repeatable (median intra-test coefficient of variation 4.1%) and reproducible (limits of agreement -1.8 to 1.6) after mean of 16 days. Functional residual capacity (FRC) measurements were significantly greater using nitrogen than SF6 or plethysmography: mean FRC measured by nitrogen washout (FRCN2) 139% predicted versus FRC measured by plethysmography 125% predicted, p<0.0001. Conclusion: LCI is most suitable as a measure of early airways disease in COPD in those with well-preserved FEV1, with similar repeatability and limitations to that observed in cystic fibrosis. Using the Exhalyzer system to perform MBWN2, however, appeared to substantially over-read FRC. This discrepancy needs addressing before FRCN2 measurements made using this device can be reliably deployed.
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Testes Respiratórios/métodos , Doença Pulmonar Obstrutiva Crônica/fisiopatologia , Adulto , Idoso , Estudos de Viabilidade , Feminino , Volume Expiratório Forçado , Capacidade Residual Funcional , Humanos , Masculino , Pessoa de Meia-Idade , Nitrogênio/análise , Reprodutibilidade dos Testes , Testes de Função Respiratória , Sensibilidade e EspecificidadeRESUMO
Ever since the first recognised outbreak of Ebolavirus in 1976, retrospective epidemiological analyses and extensive studies with animal models have given us insight into the nature of the pathology and transmission mechanisms of this virus. In this review focusing on Ebolavirus, we present an outline of our current understanding of filovirus human-to-human transmission and of our knowledge concerning the molecular basis of viral transmission and potential for adaptation, with particular focus on what we have learnt from the 2014 outbreak in West Africa. We identify knowledge gaps relating to transmission and pathogenicity mechanisms, molecular adaptation and filovirus ecology.