Publications by authors named "Barth O"

An unprecedented global outbreak caused by the monkeypox virus (MPXV) prompted the World Health Organization to declare a public health emergency of international concern on July 23, 2022. Therapeutics and vaccines for MPXV are not widely available, necessitating further studies, particularly in drug repurposing area. To this end, the standardization of in vitro infection systems is essential.

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In 2015-2016, the Zika virus (ZIKV) caused a major epidemic in the Americas, increasing cases of microcephaly and Guillain-Barré syndrome. During this period, the discovery of ZIKV sexual transmission intensified studies on the impact of this virus on the reproductive organs. For this study, 2-month-old male BALB/c mice were infected with 1.

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Michigan's CHRONICLE, the Chronic Disease Registry Linking Electronic Health Record Data, is a near-real-time disease monitoring system designed to harness electronic health record (EHR) data and existing health information exchange (HIE) infrastructure for transformative public health surveillance. Strong evidence indicates that using EHR data in chronic disease monitoring will provide rapid insight over time on health care use, outcomes, and public health interventions. We examined the potential of EHR data for chronic disease surveillance through close collaboration with our statewide HIE network and 2 participating health systems.

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This study compares the effects of virus-cell interactions among SARS-CoV-2 variants of concern (VOCs) isolated in Brazil in 2021, hypothesizing a correlation between cellular alterations and mortality and between viral load and transmissibility. For this purpose, reference isolates of Alpha, Gamma, Zeta, and Delta variants were inoculated into monolayers of Vero-E6 cells. Viral RNA was quantified in cell supernatants by RT‒PCR, and infected cells were analyzed by Transmission Electron Microscopy (TEM) for qualitative and quantitative evaluation of cellular changes 24, 48, and 72 hours postinfection (hpi).

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Monogalactosyldiacylglycerol (MGDG) is the main lipid constituent of thylakoids and a structural component of photosystems and photosynthesis-related proteo-lipid complexes in green tissues. Previously reported changes in MGDG abundance upon stress treatments are hypothesized to reflect mobilization of MGDG-based polyunsaturated lipid intermediates to maintain extraplastidial membrane integrity. While exchange of lipid intermediates between compartmental membranes is well documented, physiological consequences of mobilizing an essential thylakoid lipid, such as MGDG, for an alternative purpose are not well understood.

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Background: According to the last 2023 Monkeypox (Mpox) Outbreak Global Map from the Centres for Disease Control and Prevention (CDC), more than 100 countries with no Mpox infection report cases. Brazil stands out in this group and is the second country with the highest number of cases in the last outbreak.

Objective: To contribute to knowledge of the virus infection effects in a cellular model, which is important for diagnosis infections not yet included in a provider´s differential diagnosis and for developing viral inhibition strategies.

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Article Synopsis
  • Dengue is caused by four serotypes of the dengue virus (DENV-1 to -4), with DENV-4 being the least understood and often leading to complications like acute kidney injury in severe cases.
  • This study aimed to explore how experimental infection with DENV-4 affects kidney tissue in adult BALB/c mice, using intravenous infection and subsequent analysis of the kidneys.
  • Findings showed viral presence and significant kidney damage, including inflammation, glomerular enlargement, and necrosis of tubular cells, suggesting that while the kidney may not be a primary target for the virus, it still suffers damage from the infection.
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The heavy metal associated isoprenylated plant proteins (HIPPs) are characterized by at least one heavy metal associated (HMA) domain and a C-terminal isoprenylation motif. farnesylated protein 1 (HvFP1), a barley HIPP, is upregulated during drought stress, in response to abscisic acid (ABA) and during leaf senescence. To investigate the role of HvFP1, two independent gain-of-function lines were generated.

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The pandemic caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has impacted public health and the world economy and fueled a worldwide race to approve therapeutic and prophylactic agents, but so far there are no specific antiviral drugs. Understanding the biology of the virus is the first step in structuring strategies to combat it, and in this context several studies have been conducted with the aim of understanding the replication mechanism of SARS-CoV-2 in vitro systems. In this work, studies using transmission and scanning electron microscopy and 3D electron microscopy modeling were performed with the goal of characterizing the morphogenesis of SARS-CoV-2 in Vero-E6 cells.

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Dengue virus (DENV) infection by one of the four serotypes (DENV-1 to 4) may result in a wide spectrum of clinical manifestations, with unpredictable evolution and organ involvement. Due to its association with severe epidemics and clinical manifestations, DENV-2 has been substantially investigated. In fact, the first emergence of a new lineage of the DENV-2 Asian/American genotype in Brazil (Lineage II) in 2008 was associated with severe cases and increased mortality related to organ involvement.

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Despite the advancement of molecular biology techniques, morphological studies using transmission electron microscopy (TEM) are still being of great importance to elucidate some aspects of viral structures, morphogenesis, and pathogenesis. In relation to dengue viruses (DENV), several studies report the use of TEM to obtain a clearer definition of viral morphology, the events involved in its morphogenesis, aspects of pathogenesis, and cell tropism. In this chapter, the main technical protocols and their respective reagents for studies of DENV infection by TEM are described, both in cell culture and in biological tissue samples.

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Dengue virus type 2 (DENV-2) is, traditionally, the most studied serotype due to its association with explosive outbreaks and severe cases. In Brazil, almost 20 years after the first introduction in the 1990s, a new lineage (Lineage II) of the DENV-2 Asian/American genotype emerged and caused an epidemic with severe cases and hospitalizations. Severe dengue includes multiple organ failure, and renal involvement can be potentially related to increased mortality.

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Dengue (DEN) is the most prevalent arbovirus among humans, and four billion people live at risk of infection. The clinical manifestations of DEN are variable, and the disease may present subclinically or asymptomatically. A quarter of patients develop classical dengue (CD) or severe dengue (SD), which is potentially lethal and involves vascular permeability changes, severe hemorrhage and organ damage.

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Article Synopsis
  • Coronaviruses, particularly SARS-CoV, MERS-CoV, and the newly identified SARS-CoV-2, have caused significant respiratory diseases and global pandemic concerns since late 2019, leading to urgent calls for research and development of treatments and vaccines.
  • * This study focuses on examining the biology of SARS-CoV-2 in Vero-E6 cells using transmission electron microscopy and RT-PCR to understand how the virus infects these cells.
  • * Results indicated that SARS-CoV-2 infects Vero-E6 cells through endocytic pathways or membrane fusion, causing visible cellular damage and indicating viral maturation occurs via budding from the rough endoplasmic reticulum.
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Background: The impact of arbovirus cocirculation in Brazil is unknown. Dengue virus (DENV) reinfection may result in more intense viraemia or immunopathology, leading to more severe disease. The Zika virus (ZIKV) epidemic in the Americas provided pathogenicity evidence that had not been previously observed in flavivirus infections.

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Dengue, considered the most important arthropod-borne viral disease affecting humans, is transmitted by the bite of mosquitoes of the genus Aedes and caused by one of the four distinct serotypes of dengue virus (DENV-1, -2, -3 and -4). Infection with one of the four serotypes provides lifelong homotypic immunity. However, immunity against the heterologous serotypes is transient.

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Platelets play a role in hemostasis, coagulation, angiogenesis, inflammation and immune response is one of the most affected cells in dengue. Here we describe some aspects of platelets by observing their specific circulating mediators, the ability to interact with the virus and morphological consequences of this interaction, activation markers and intraplatelet protein contents in dengue. We conducted this study using dengue-patients as well as healthy donors.

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After publication of the original article [1] it was noted that the name of author, D. Luke Fisher, was erroneously typeset in both the PDF and online formats of the manuscript as Luke D. Fisher.

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Background: Converging evidence suggests a role for microglia-mediated neuroinflammation in Parkinson's disease (PD). Animal models of PD can serve as a platform to investigate the role of neuroinflammation in degeneration in PD. However, due to features of the previously available PD models, interpretations of the role of neuroinflammation as a contributor to or a consequence of neurodegeneration have remained elusive.

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Article Synopsis
  • The absence of an effective animal model for dengue research hinders vaccine and drug development, making this study significant.
  • Prior research showed that BALB/c mice are susceptible to dengue viruses 1 and 2, and this study extends the investigation to DENV-4 by infecting these mice and analyzing their saliva.
  • The study successfully detected DENV-4 RNA in the saliva of infected mice, highlighting a correlation to human infection, even though saliva testing is not traditionally used for dengue diagnosis.
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  • Mammarenaviruses are typically associated with specific rodent host species, but recent findings indicate that multiple host species may harbor these viruses, challenging previous assumptions about their co-evolution.
  • A study in Brazil identified a new rodent reservoir species (Calomys callidus) linked to the Latino mammarenavirus (LATV), with genetic analysis revealing a well-supported group of LATV strains.
  • The research suggests that our understanding of mammarenavirus dynamics in South America is evolving, indicating that further studies in non-endemic areas may uncover additional animal hosts for these viruses.
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Zika virus (ZIKV) is a member of the flavivirus genus, and its genome is approximately 10.8 kilobases of positive-strand RNA enclosed in a capsid and surrounded by a membrane. Studies on the replication dynamics of ZIKV are scarce, which limits the development of antiviral agents and vaccines directed against ZIKV.

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Zika virus (ZIKV) has infected thousands of Brazilian people and spread to other American countries since 2015. The introduction of ZIKV brought a strong impact to public health in Brazil. It is of utmost importance to identify a susceptible cell line that will enable the isolation and identification of the virus from patient samples, viral mass production, and testing of drug and vaccine candidates.

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In cell culture, cell structures suffer strong impact due to centrifugation during processing for electron microscope observation. In order to minimise this effect, a new protocol was successfully developed. Using conventional reagents and equipments, it took over one week, but cell compression was reduced to none or the lowest deformation possible.

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Pollen is used in the human diet as a food supplement because of its high nutritional value; however, this product is prone to fungal contamination that could potentially generate toxins that are harmful to human health. This study aimed to verify the floral diversity of commercial brands of bee pollen and their mycotoxicological safety for human consumption. A total of 27 bee pollen samples were analyzed; these samples represented commercial brands, either showing an inspection seal or not, marketed in the State of Rio de Janeiro.

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