Oropharyngeal Group A Streptococcal Colonization Disrupts Latent Epstein-Barr Virus Infection

Epstein-Barr virus (EBV) infects >90% of the human population within the first 2 decades of life and establishes reversible latent infection in B cells. The stimuli that lead to switching from latent to lytic EBV infection in vivo are still elusive. Group A streptococci (GAS) are a common cause of bacterial pharyngotonsillitis in children and adolescents and colonize the tonsils and pharynx of up to 20% of healthy children. Thus, concomitant presence of EBV and GAS in the same individual is frequent. Here, we show that EBV carriers who are colonized with GAS shed EBV particles in higher numbers in their saliva, compared with EBV carriers not colonized with GAS. Messenger RNA levels of the master lytic regulatory EBV gene BZLF1 were more frequently detected in tonsils from EBV carriers colonized with GAS than from EBV carriers not colonized. Heat-killed GAS, potentially mimicking GAS colonization, elicited lytic EBV in latently infected lymphoblastoid cell lines (LCLs) partially via Toll-like receptor 2 triggering, as did purified GAS peptidoglycan. Thus, colonization by GAS might benefit EBV by increasing the EBV load in saliva and thereby enhancing the likelihood of EBV spread to other host

Contrasting ring-opening propensities in UV-excited α-pyrone and coumarin

Ring-opening quantum yields following UV-photoexcitation of coumarin and α-pyrone are influenced by the dynamics through, rather than just the geometries of, conical intersections.</p

Cochlear implantation in patients with bilateral deafness caused by otitis media with ANCA-associated vasculitis (OMAAV): A report of four cases

Objective: Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) without systemic symptoms but with initial symptoms related to the ear, such as hearing loss, otalgia, and dizziness, has recently been reported. We have categorized this condition as otitis media with AAV (OMAAV), and have recently proposed its diagnostic criteria. Methods: To determine the effectiveness of cochlear implantation (CI) in patients with profound hearing loss due to OMAAV. We examined the language understanding ability of four patients with bilateral profound or total deafness due to OMAAV, who underwent CI. Results: In three of the four patients, the language understanding ability with CI was poor. These three patients with poor performance had characteristic features, including a short interval from the onset of ear symptoms to total deafness and clear enhancement of the cochlea on magnetic resonance imaging (MRI). Conclusion: The poor results observed in patients with a rapidly progressive history of hearing loss were attributed to possible severe and profuse intracochlear bleeding and/or destruction of structures, including the spiral ganglion. All the three patients showed contrast enhancement in the inner ear on MRI. We believe that preoperative evaluation of the history of hearing loss as well as the findings of contrast-enhanced MRI is important for predicting the prognosis after CI

Risk factors for otitis media in children with special emphasis on the role of colonization with bacterial airway pathogens: the Generation R study

Acute otitis media is the most frequent diagnosis in children visiting physicians’ offices. Risk factors for otitis media have been widely studied. Yet, the correlation between bacterial carriage and the development of otitis media is not entirely clear. Our aim was to study in a population-based prospective cohort the risk factors for otitis media in the second year of life with special emphasis on the role of colonization with Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis. The study was embedded in the Generation R Study. Data on risk factors and doctor-diagnosed otitis media were obtained by midwives, hospital registries and postal questionnaires in the whole cohort (n = 7,295). Nasopharyngeal swabs were obtained at the age of 1.5, 6 and 14 months in the focus cohort (n = 1,079). Of these children, 2,515 (47.2%) suffered at least one period of otitis media in their second year of life. The occurrence of otitis media during the follow-up period in the first 6 months of life and between 6 and 12 months of age was associated with the risk of otitis media in the second year of life (aOR, 1.83 95% CI 1.24–2.71 and aOR 2.72, 95% CI 2.18–3.38, respectively). Having siblings was associated with an increased risk for otitis media in the second year of life (aOR 1.42, 95% CI 1.13–1.79). No associations were found between bacterial carriage in the first year of life and otitis media in the second year of life. In our study, otitis media in the first year of life is an independent risk factor for otitis media in the second year of life. Surprisingly, bacterial carriage in the first year of life did not add to this risk. Moreover, no association was observed between bacterial carriage in the first year of life and otitis in the second year of life

The enhanced expression of the matrix metalloproteinase 9 in nasal NK/T-cell lymphoma

<p>Abstract</p> <p>Background</p> <p>Nasal NK/T cell lymphoma is an aggressive disease and has a poor prognosis. Nasal NK/T cell lymphoma is refractory to conventional chemotherapy and has strong tendency of widespread relapse or dissemination into distant sites.</p> <p>Methods</p> <p>We immunohistochemically studied nasal NK/T-cell lymphoma to elucidate the unique characteristics of nasal NK/T-cell lymphoma, such as its higher metastatic tendency and its vast necrosis which leads to destruction of the involved tissues. The expression of P-glycoprotein and MMP-9 was evaluated in the 20 patients with nasal NK/T-cell lymphoma and 25 with nasal non-NK/T-cell lymphoma and the relationship between expression of these proteins and clinical results were analyzed in this report.</p> <p>Results</p> <p>Overall 5-year survival rates for patients with nasal NK/T cell lymphoma, and nasal non-NK/T cell lymphoma were 51%, and 84%. Distant involvement free 5-year survival rates for patients with nasal NK/T cell lymphoma, and nasal non-NK/T cell lymphoma were 53%, and 79%.</p> <p>Overall positivity for P-glycoprotein was observed in 10 of 19 patients with NTL and in 13 of 23 patients with non-NTL. When the overall survival rate was compared between patients with P-glycoprotein positive and negative, there was no difference between them.</p> <p>Sixteen of the 19 patients with nasal NK/T cell lymphoma expressed MMP-9. In contrast, only 8 of the 22 patients with nasal non-NK/T cell lymphoma expressed MMP-9. Distant involvement free 5-year survival rates for patients with MMP-9 negative, and MMP-9 positive were 92%, and 61%, respectively. The difference was statistically significant (p = 0.027).</p> <p>Conclusion</p> <p>Positive immunoreactivity for P-glycoprotein was not an independent prognostic factor in nasal NK/T-cell lymphomas, which stresses the importance of exploring other mechanisms of drug resistance. The strong expression of MMP-9 is uniquely characteristic of nasal NK/T cell lymphoma and may contribute to its strong tendency to disseminatate and the extensive necrosis which is always seen. However, our results are based on univariate comparisons, and as such, should be viewed with some caution.</p

Phosphorylcholine Allows for Evasion of Bactericidal Antibody by Haemophilus influenzae

The human pathogen Haemophilus influenzae has the ability to quickly adapt to different host environments through phase variation of multiple structures on its lipooligosaccharide (LPS), including phosphorylcholine (ChoP). During colonization with H. influenzae, there is a selection for ChoP+ phase variants. In a murine model of nasopharyngeal colonization, this selection is lost in the absence of adaptive immunity. Based on previous data highlighting the importance of natural antibody in limiting H. influenzae colonization, the effect of ChoP expression on antibody binding and its bactericidal activity was investigated. Flow cytometric analysis revealed that ChoP+ phase variants had decreased binding of antibody to LPS epitopes compared to ChoP− phase variants. This difference in antibody binding correlated with increased survival of ChoP+ phase variants in the presence of antibody-dependent, complement-mediated killing. ChoP+ phase variants were also more resistant to trypsin digestion, suggesting a general effect on the physical properties of the outer membrane. Moreover, ChoP-mediated protection against antibody binding correlated with increased resilience of outer membrane integrity. Collectively, these data suggest that ChoP expression provides a selective advantage during colonization through ChoP-mediated effects on the accessibility of bactericidal antibody to the cell surface

A significant role of the totally symmetric valley-ridge inflection point in the bifurcating reaction pathway

Appearance of the valley-ridge inflection (VRI) point on the intrinsic reaction path (IRP) introduces geometrical instability of the reaction coordinate, and sometimes leads to two different product minima on the potential energy surface (PES). A significant role of the totally-symmetric VRI point on the IRP is discussed from the viewpoint of branching of the reaction pathway. As illustrative examples, ab initio calculations were performed to determine the IRP for XCHO^[-] + CH3Cl (X = H, CH3) at the Møller-Plesset second-order perturbation theory (MP2) level with 6-31+G(d) basis sets and geometric features of the PES around the IRP have been analyzed

Trifurcation of the reaction pathway

A concept of trifurcation of a reaction pathway is introduced to analyze the case where a downhill path from the first-order saddle point accompanies three branches via the valley-ridge inflection region, leading to three different product minima on the potential energy surface. We provide a detailed analysis on the reaction path for an electron transfer reaction, HCHO- + CH3Cl → OH2C-CH3⋅⋅⋅Cl-, as an illustrative example of the trifurcating reaction path

Combined gradient projection/single component artificial force induced reaction (GP/SC-AFIR) method for an efficient search of minimum energy conical intersection (MECI) geometries

We report a new approach to search for structures of minimum energy conical intersection (MECIs) automatically. Gradient projection (GP) method and single component artificial force induced reaction (SC-AFIR) method were combined in the present approach. As case studies, MECIs of benzene and naphthalene between their ground and first excited singlet electronic states (S-0/S-1-MECIs) were explored. All S-0/S-1-MECIs reported previously were obtained automatically. Furthermore, the number of force calculations was reduced compared to the one required in the previous search. Improved convergence in a step in which various geometrical displacements are induced by SC-AFIR would contribute to the cost reduction. (C) 2017 Elsevier B.V. All rights reserved