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Topic Review
Biological Time and Host-Virus Interaction
Living beings spend their lives and carry out their daily activities interacting with environmental situations that present space-time variations and that involve contact with other life forms, which may behave as commensals or as invaders and/or parasites. The characteristics of the environment, as well as the processes that support the maintenance of life and that characterize the execution of activities of daily life generally present periodic variations, which are mostly synchronized with the light–dark cycle determined by Earth’s rotation on its axis. These rhythms with 24-h periodicity, defined as circadian, influence events linked to the interaction between hosts and hosted microorganisms and can dramatically determine the outcome of this interplay. 
  • 997
  • 10 Nov 2022
Topic Review
Gut Microbiome and Adjuvant Treatment of COVID-19
High expression of the transmembrane protein angiotensin I converting enzyme 2 (ACE2), more than 100-times higher as in the lung, and transmembrane serine protease 2 (TMPRSS2) in the gastrointestinal tract leads to infection with SARS-CoV-2. According to meta-analysis data, 9.8–20% of COVID-19 patients experience gastrointestinal symptoms, where diarrhoea is the most frequent, and about 50% shed viruses with high titre through their faeces, where a first faecal transmission was reported. Furthermore, gut inflammation, intestinal damage, and weakening of the gut mucosal integrity that leads to increased permeability has been shown in different studies for COVID-19 patients. This can lead to increased inflammation and bacteraemia. Low mucosal integrity combined with low intestinal damage is a good predictor for disease progression and submission to the intensive care unit (ICU). Several pilot studies have shown that the gut microbiome of COVID-19 patients is changed, microbial richness and diversity were lower, and opportunistic pathogens that can cause bacteraemia were enriched compared to a healthy control group. In a large proportion of these patients, dysbiosis was not resolved at discharge from the hospital and one study showed dysbiosis is still present after 3 months post COVID-19. Consequently, there might be a link between dysbiosis of the gut microbiome in COVID-19 patients and chronic COVID-19 syndrome (CCS). Various clinical trials are investigating the benefit of probiotics for acute COVID-19 patients, the majority of which have not reported results yet. However, two clinical trials have shown that a certain combination of probiotics is beneficial and safe for acute COVID-19 patients. Mortality was 11% for the probiotic treatment group, and 22% for the control group. Furthermore, for the probiotic group, symptoms cleared faster, and an 8-fold decreased risk of developing a respiratory failure was calculated. In conclusion, evidence is arising that inflammation, increased permeability, and microbiome dysbiosis in the gut occur in COVID-19 patients and thus provide new targets for adjuvant treatments of acute and chronic COVID-19. More research in this area is needed.
  • 993
  • 23 Nov 2021
Topic Review
Prime-Boost COVID-19 Vaccination against SARS-CoV-2
The types of these vaccines include two recombinant adenovirus vaccines (ChAdOx1-S and Ad26.COV2-S), one heterologous recombinant adenovirus vaccine (Gam-COVID-Vac), two mRNA vaccines (BNT162b2 and mRNA-1273), two inactivated virus vaccines (BBIBP-CorV and CoronaVac), and one recombinant protein vaccine (NVX-CoV2373).
  • 993
  • 07 Dec 2021
Topic Review
Oncolytic Adenovirus Therapy
Oncolytic adenovirus therapy is gaining importance as a novel treatment option for the management of various cancers. Different concepts of modification within the adenovirus vector have been identified that define the mode of action against and the interaction with the tumour. Adenoviral vectors allow for genetic manipulations that restrict tumour specificity and also the expression of specific transgenes in order to support the anti-tumour effect. Additionally, replication of the virus and reinfection of neighbouring tumour cells amplify the therapeutic effect. Another important aspect in oncolytic adenovirus therapy is the virus induced cell death which is a process that activates the immune system against the tumour. 
  • 989
  • 11 Nov 2021
Topic Review
Protein Antibodies in Respiratory Syncytial Infection
Respiratory syncytial virus infection (RSVI) is an acute medical and social problem in many countries globally. Infection is most dangerous for infants under one year old and the elderly. Despite its epidemiological relevance, only two drugs are registered for clinical use against RSVI: ribavirin (approved in a limited number of countries due to side effects) and palivizumab (Synagis), which is intended only for the prevention, but not the treatment, of infection. Various research are searching for new drugs against RSV, with three main areas of research: small molecules, polymeric drugs (proteins and peptides), and plant extracts. 
  • 989
  • 10 Jun 2022
Topic Review
Torque Teno Sus Virus
Torque teno sus virus (TTSuV) belongs to the Anelloviridae family. TTSuV is a non-enveloped circular ssDNA virus which frequently infects swine and has been associated with hepatic, respiratory, and autoimmune disorders. TTSuV pathogenic role is still uncertain, and clear data in the literature on virus reservoirs are lacking.
  • 988
  • 09 Feb 2022
Topic Review
Ranaviral and Frog Virus 3
Ranaviruses (Iridoviridae), including Frog Virus 3 (FV3), are large dsDNA viruses that cause devastating infections globally in amphibians, fish, and reptiles, and contribute to catastrophic amphibian declines. Our findings imply that Ranaviruses like FV3 have acquired previously unknown molecular mimics, interfering with host IFN signaling during evolution.
  • 987
  • 11 Nov 2021
Topic Review
Hepatitis-B-Virus-Induced Hepatocellular Carcinoma
Hepatocellular carcinoma (HCC) remains a global health challenge, causing 600,000 deaths each year. Infectious factors, including hepatitis B virus (HBV), hepatitis C virus (HCV) and hepatitis D virus (HDV), have long been considered the major risk factors for the development and progression of HCC. These pathogens induce hepatocyte transformation through a variety of mechanisms, including insertional mutations caused by viral gene integration, epigenetic changes, and the induction of long-term immune dysfunction.
  • 982
  • 17 May 2023
Topic Review
Placenta in SARS-CoV-2 Infection
A pandemic of acute respiratory infections, due to a new type of coronavirus, can cause Severe Acute Respiratory Syndrome 2 (SARS-CoV-2) and has created the need for a better understanding of the clinical, epidemiological, and pathological features of COVID-19, especially in high-risk groups, such as pregnant women. Viral infections in pregnant women may have a much more severe course, and result in an increase in the rate of complications, including spontaneous abortion, stillbirth, and premature birth—which may cause long-term consequences in the offspring. In this review, we focus on the mother-fetal-placenta interface and its role in the potential transmission of SARS-CoV-2, including expression of viral receptors and proteases, placental pathology, and the presence of the virus in neonatal tissues and fluids. 
  • 980
  • 15 Jun 2021
Topic Review
Influence on Habitat on Neotropical Rodents Viral Diversity
Ecosystem disturbances and resulting decreases of host species richness have been associated with the emergence of zoonotic diseases. Among vertebrates, rodents are important reservoirs of numerous viruses, including some with significant impacts on public health. Exploring the viral diversity in Neotropical rodents, we provide significant insights into zoonotic viruses in Amazonia, and emphasize that habitats and host’s dietary ecology drive viral diversity. Linking richness and abundance of viruses to the ecology and responses to habitat disturbance of their hosts should be starting points for a better understanding of viral emergence, prediction of at-risk situation, and implementation of early control and mitigation measures.
  • 980
  • 01 Nov 2021
Topic Review
Rheumatology Drugs for COVID-19
While waiting for the development of specific antiviral therapies and vaccines to effectively neutralize the SARS-CoV2, a relevant therapeutic strategy is to counteract the hyperinflammatory status, characterized by an increase mainly of interleukin (IL)-1β, IL-2, IL-6, IL-7, IL-8, and tumor necrosis factor (TNF)-α, which hallmarks the most severe clinical cases. ‘Repurposing’ immunomodulatory drugs and applying clinical management approved for rheumatic diseases represents a game-changer option.
  • 976
  • 02 Mar 2021
Topic Review
Major Factors That Affect cccDNA Half-Life
Eradication of covalently closed circular DNA (cccDNA) is an ideal goal of chronic hepatitis B (CHB) therapy. Understanding the changes in the cccDNA pool during therapy provides a basis for developing CHB treatment strategies. Central to the description of cccDNA dynamics is a parameter called cccDNA half-life. CccDNA half-life is not an intrinsic property of cccDNA molecules, but a description of an observed phenomenon characterized by cccDNA pool decline. Since cccDNA has to be in the nuclei of host cells to function, the half-life of cccDNA is determined by the state and destiny of the host cells.
  • 974
  • 08 Mar 2023
Topic Review
Role of Lithium in SARS-CoV-2
Lithium possesses the ability to depolarize the resting membrane potential of the cell. It has been proposed that lithium treats bipolar patients by membrane depo-larization of neuronal cells that is triggered by quantum tunneling of lithium ions through sodium channels when lithium reaches its therapeutic concentration.
  • 970
  • 12 Mar 2021
Topic Review
Molecular Biology of Hepatitis B Virus
Chronic infection with the hepatitis B virus (HBV) affects an estimated 257 million people worldwide and can lead to liver diseases such as cirrhosis and liver cancer. Viral replication is generally considered not to be cytopathic. Nevertheless, some HBV proteins have direct carcinogenic effects, and chronic inflammation resulting from disrupted antiviral responses and aberrant innate immune reactions lead to HBV infection-related disease and mortality in up to 25% of cases. HBV is an enveloped virus. The enveloped core particle contains the viral polymerase and the partially double stranded HBV DNA genome. The DNA is generated from an RNA template and thus the virus should be classified as a retrovirus. The virus has one accessory protein, the X protein (HBx), which is the main viral oncogene. HBx expression is essential to initiate and maintain viral RNA transcription. 
  • 969
  • 06 Jan 2023
Topic Review
Mosquito-Associated Viruses in West Africa
A cumulative number of MAVs are being discovered in hematophagous arthropods all over the world. There is a potential impact on the fitness and competence of the vector. Therefore, more research is needed to expand the knowledge about their prevalence, distribution, and diversity. The trend of MAVs reported in the literature enlightens how researches about MAVs are on the increase. The past decades have shown a dramatic surge in the literature recounting novel MSVs and classical arboviruses. The increase in research interest has provided new understanding about viral diversity and evolution. Finally, the new viruses discovered have created curiosity in their use as potential biological control agents. 
  • 967
  • 11 Jun 2021
Topic Review
HPV Oncoproteins and Innate Immunity
The growth of human papillomavirus (HPV)-transformed cells depends on the ability of the viral oncoproteins E6 and E7, especially those from high-risk HPV16/18, to manipulate the signaling pathways involved in cell proliferation, cell death, and innate immunity. Emerging evidence indicates that E6/E7 inhibition reactivates the host innate immune response, reversing what until then was an unresponsive cellular state suitable for viral persistence and tumorigenesis. Given that the disruption of distinct mechanisms of immune evasion is an attractive strategy for cancer therapy, the race is on to gain a better understanding of E6/E7-induced immune escape and cancer progression. Here, we review recent literature on the interplay between E6/E7 and the innate immune signaling pathways cGAS/STING/TBK1, RIG-I/MAVS/TBK1, and Toll-like receptors (TLRs). The overall emerging picture is that E6 and E7 have evolved broad-spectrum mechanisms allowing for the simultaneous depletion of multiple rather than single innate immunity effectors. The cGAS/STING/TBK1 pathway appears to be the most heavily impacted, whereas the RIG-I/MAVS/TBK1, still partially functional in HPV-transformed cells, can be activated by the powerful RIG-I agonist M8, triggering the massive production of type I and III interferons (IFNs), which potentiates chemotherapy-mediated cell killing. Overall, the identification of novel therapeutic targets to restore the innate immune response in HPV-transformed cells could transform the way HPV-associated cancers are treated.
  • 966
  • 10 Mar 2021
Topic Review
Bird-Related Rhabdoviruses Circulating in Africa
Rhabdoviridae is the most diverse family of the negative, single-stranded RNA viruses, which includes 40 ecologically different genera that infect plants, insects, reptiles, fishes, and mammals, including humans, and birds. To date, only a few bird-related rhabdoviruses among the genera Sunrhavirus, Hapavirus, and Tupavirus have been described and analyzed at the molecular level.
  • 965
  • 16 Nov 2021
Topic Review
Gamma-Delta T Cells
Recent advances in γδ T cell biology have focused on the unique attributes of these cells and their role in regulating innate and adaptive immunity, promoting tissue homeostasis, and providing resistance to various disorders. Numerous bacterial and viral pathogens, including human immunodeficiency virus-1 (HIV), greatly alter the composition of γδ T cells in vivo. Despite the effectiveness of antiretroviral therapy (ART) in controlling HIV and restoring health in those affected, γδ T cells are dramatically impacted during HIV infection and fail to reconstitute to normal levels in HIV-infected individuals during ART for reasons that are not clearly understood. Importantly, their role in controlling HIV infection, and the implications of their failure to rebound during ART are also largely unknown and understudied.
  • 964
  • 13 Jan 2021
Topic Review
Universal Influenza Vaccine Human Trials
On average, there are 3–5 million severe cases of influenza virus infections globally each year. Seasonal influenza vaccines provide limited protection against divergent influenza strains. Therefore, the development of a universal influenza vaccine is a top priority for the NIH. Here, we report a comprehensive summary of all universal influenza vaccines that were tested in clinical trials during the 2010–2019 decade. Of the 1597 studies found, 69 eligible clinical trials, which investigated 27 vaccines, were included in this review. Information from each trial was compiled for vaccine target, vaccine platform, adjuvant inclusion, clinical trial phase, and results. As we look forward, there are currently three vaccines in phase III clinical trials which could provide significant improvement over seasonal influenza vaccines. This systematic review of universal influenza vaccine clinical trials during the 2010–2019 decade provides an update on the progress towards an improved influenza vaccine.
  • 964
  • 12 May 2021
Topic Review
SARS-CoV-2 Dysregulates Neutrophil Degranulation and Reduces Lymphocyte Counts
SARS-CoV-2, the virus that causes COVID-19, has given rise to one of the largest pandemics, affecting millions worldwide. High neutrophil-to-lymphocyte ratios have been identified as an important correlate to poor recovery rates in severe COVID-19 patients. However, the mechanisms underlying this clinical outcome and the reasons for its correlation to poor prognosis are unclear. Furthermore, the mechanisms involved in healthy neutrophils acquiring a SARS-CoV-2-mediated detrimental role are yet to be fully understood. 
  • 964
  • 14 Mar 2022
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