Mutations in Polymerase Genes Enhanced the Virulence of 2009 Pandemic H1N1 Influenza Virus in Mice

Influenza A virus can infect a wide variety of animal species with illness ranging from mild to severe, and is a continual cause for concern. Genetic mutations that occur either naturally or during viral adaptation in a poorly susceptible host are key mechanisms underlying the evolution and virulence of influenza A virus. Here, the variants containing PA-A36T or PB2-H357N observed in the mouse-adapted descendants of 2009 pandemic H1N1 virus (pH1N1), A/Sichuan/1/2009 (SC), were characterized. Both mutations enhanced polymerase activity in mammalian cells. These effects were confirmed using recombinant SC virus containing polymerase genes with wild type (WT) or mutant PA or PB2. The PA-A36T mutant showed enhanced growth property compared to the WT in both human A549 cells and porcine PK15 cells in vitro, without significant effect on viral propagation in murine LA-4 cells and pathogenicity in mice; however, it did enhance the lung virus titer. PB2-H357N variant demonstrated growth ability comparable to the WT in A549 cells, but replicated well in PK15, LA-4 cells and in mice with an enhanced pathogenic phenotype. Despite such mutations are rare in nature, they could be observed in avian H5 and H7 subtype viruses which were currently recognized to pose potential threat to human. Our findings indicated that pH1N1 may adapt well in mammals when acquiring these mutations. Therefore, future molecular epidemiological surveillance should include scrutiny of both markers because of their potential impact on pathogenesis

Evolutionary and transmission dynamics of reassortant H5N1 influenza virus in Indonesia.

H5N1 highly pathogenic avian influenza (HPAI) viruses have seriously affected the Asian poultry industry since their recurrence in 2003. The viruses pose a threat of emergence of a global pandemic influenza through point mutation or reassortment leading to a strain that can effectively transmit among humans. In this study, we present phylogenetic evidences for the interlineage reassortment among H5N1 HPAI viruses isolated from humans, cats, and birds in Indonesia, and identify the potential genetic parents of the reassorted genome segments. Parsimony analyses of viral phylogeography suggest that the reassortant viruses may have originated from greater Jakarta and surroundings, and subsequently spread to other regions in the West Java province. In addition, Bayesian methods were used to elucidate the genetic diversity dynamics of the reassortant strain and one of its genetic parents, which revealed a more rapid initial growth of genetic diversity in the reassortant viruses relative to their genetic parent. These results demonstrate that interlineage exchange of genetic information may play a pivotal role in determining viral genetic diversity in a focal population. Moreover, our study also revealed significantly stronger diversifying selection on the M1 and PB2 genes in the lineages preceding and subsequent to the emergence of the reassortant viruses, respectively. We discuss how the corresponding mutations might drive the adaptation and onward transmission of the newly formed reassortant viruses

An analysis of the antimicrobial activity of ten root canal sealers - A duration based in vitro evaluation

Aim and Design: Sealers with prolonged antimicrobial activity are needed by the fact that microorganisms are commonly recovered from teeth with failed endodontic therapy. The aim of this study was to evaluate the duration of antimicrobial activity of ten root canal sealers (Apexit plus, Tubli Seal Xpress, Endoflas FS, Endomethasone, Endomethasone N, AH Plus, Epiphany, EndoRez, Ketac Endo, Roeko Seal) against Enterococcus faecalis and Candida albicans by the agar diffusion test. The zones of inhibition were examined immediately and after 24, 48, 72 hours, 5 and 7 days. Statistical analysis was done using Kruskal - Wallis test and Mann Whitney U test.Results and conclusions: Against Enterococcus faecalis, Endoflas FS showed the largest inhibitory zones immediately and 24 hours after manipulation, whereas, there was no significant difference between Endoflas FS and Endomethasone after 48 hours. Against Candida albicans, Endoflas FS performed better than the other sealers. All the sealers (except AH Plus, Epiphany and Roeko Seal) demonstrated higher antimicrobial action in the first 24 hours after manipulation The antimicrobial action of all the sealers (except AH Plus and Roeko Seal which showed no antimicrobial activity in any studied time and Epiphany which ceased to show any antimicrobial action after 24 hours) decreased significantly with time.Link_to_subscribed_fulltex

Restoring function and esthetics in a pair of twins with amelogenesis imperfecta

Background: Rehabilitation of complicated cases poses difficulty in clinical practice, both with respect to restoring function as well as esthetics. One such condition where the clinical practitioner has to give importance to proper planning of the treatment and execution of the plan is amelogenesis imperfecta, wherein both esthetics and function are compromised. A review of literature showed that there are no reports of management of amelogenesis imperfecta (AI) in twins. Case Description: This report discusses the esthetic and functional rehabilitation of a pair of fraternal twins with amelogenesis imperfecta. Both patients presented with esthetic disharmonies and sensitivity of teeth. The treatment plan was custom made for both the patients and executed successfully. Clinical Implications: Cosmetic rehabilitation of patients with AI has been open to a variety of treatment options. There is no set rule in planning the treatment for such cases. The aim is to properly diagnose the case and provide durable functional and esthetic management of these patients, where the unaesthetic appearance has a definite negative psychological impact.Link_to_subscribed_fulltex

Persistence of platelet thrombus formation in arterioles of mice lacking both von Willebrand factor and fibrinogen

We used intravital microscopy to observe the formation of platelet plugs in ferric chloride-injured arterioles of live mice. With this model, we evaluated thrombus growth in mice lacking von Willebrand factor (vWF) and fibrinogen (Fg), the two key ligands known to mediate platelet adhesion and aggregation. In vWF(-/-) mice, despite the presence of arterial shear, delayed platelet adhesion occurred and stable thrombi formed. In many mice, a persisting high-shear channel never occluded. Abundant thrombi formed in Fg(-/-) mice, but they detached from the subendothelium, which ultimately caused downstream occlusion in all cases. Surprisingly, mice deficient in both vWF and Fg successfully formed thrombi with properties characteristic of both mutations, leading to vessel occlusion in the majority of vessels. Platelets of these doubly deficient mice specifically accumulated fibronectin in their alpha-granules, suggesting that fibronectin could be the ligand supporting the platelet aggregation.Platelet adhesion molecules in thrombosis and hemostasisHeart and Stroke Foundation of CanadaPost doctoral fellowshi

Integrated immune networks in SARS-CoV-2 infected pregnant women reveal differential NK cell and unconventional T cell activation

Although pregnancy poses a greater risk for severe COVID-19, the underlying immunological changes associated with SARS-CoV-2 infection during pregnancy are poorly understood. We defined immune responses to SARS-CoV-2 in pregnant and non-pregnant women during acute and convalescent COVID-19 up to 258 days post symptom onset, quantifying 217 immunological parameters. Additionally, matched maternal and cord blood were collected from COVID-19 convalescent pregnancies. Although serological responses to SARS-CoV-2 were similar in pregnant and non-pregnant women, cellular immune analyses revealed marked differences in key NK cell and unconventional T cell responses during COVID-19 in pregnant women. While NK, γδ T cells and MAIT cells displayed pre-activated phenotypes in healthy pregnant women when compared to non-pregnant age-matched women, activation profiles of these pre-activated NK and unconventional T cells remained unchanged at acute and convalescent COVID-19 in pregnancy. Conversely, activation dynamics of NK and unconventional T cells were prototypical in non-pregnant women in COVID-19. In contrast, activation of αβ CD4 + and CD8 + T cells, T follicular helper cells and antibody-secreting cells was similar in pregnant and non-pregnant women with COVID-19. Elevated levels of IL-1β, IFN-γ, IL-8, IL-18 and IL-33 were also found in pregnant women in their healthy state, and these cytokine levels remained elevated during acute and convalescent COVID-19. Collectively, our study provides the first comprehensive map of longitudinal immunological responses to SARS-CoV-2 infection in pregnant women, providing insights into patient management and education during COVID-19 pregnancy