418 research outputs found
Preceding human metapneumovirus infection increases adherence of Streptococcus pneumoniae and severity of murine pneumococcal pneumonia
BackgroundCoinfection with respiratory virus and Streptococcus pneumoniae has been frequently reported in several epidemiologic studies. The aim of this study was to explore the effect of preceding human metapneumovirus (hMPV) inoculation on subsequent pneumococcal infection.MethodsHep-2 and A549 cells were infected with hMPV then inoculated with S. pneumoniae. Bacterial adhesion was measured using colony forming unit and cytometric-fluorescence assays. In vivo bacterial adhesion was examined in hMPV-infected mice after inoculation of fluorescence-conjugated S. pneumoniae. Pulmonary inflammation (bacterial titers, cytokine levels, and histopathology) of hMPV-infected mice was investigated after inoculation with S. pneumoniae.ResultsIn vitro results of bacterial infection with S. pneumoniae on A549 and Hep-2 monolayer cells showed that even though cellular adherence was variable among different serotypes, there was significantly enhanced bacterial adherence in A549 cells with preceding hMPV infection. In addition, in vivo study of hMPV-infected mice showed increased adhesion of S. pneumoniae on the bronchial epithelium with delayed bacterial clearance and exacerbated histopathology. Furthermore, mice with preceding hMPV infection showed repressed recruitment of airway neutrophils with decreased expression of neutrophil chemoattractants during pneumococcal infection.ConclusionThese results suggest that hMPV-infected airway cells, especially the lower airway epithelium, express increased adherence with S. pneumoniae. Furthermore, hMPV-infected mice showed impaired recruitment of airway neutrophils, possibly leading to delayed bacterial clearance and exacerbated pulmonary inflammation, after secondary infection with pneumococcal isolates
Maternal Vitamin D Level Is Associated with Viral Toll-Like Receptor Triggered IL-10 Response but Not the Risk of Infectious Diseases in Infancy
Stat3 and CCAAT/enhancer binding protein beta (C/EBP-beta) regulate Jab1/CSN5 expression in mammary carcinoma cells
Observation of in
Using a sample of events recorded with
the BESIII detector at the symmetric electron positron collider BEPCII, we
report the observation of the decay of the charmonium state
into a pair of mesons in the process
. The branching fraction is measured for the first
time to be , where the first uncertainty is
statistical, the second systematic and the third is from the uncertainty of
. The mass and width of the are
determined as MeV/ and
MeV.Comment: 13 pages, 6 figure
First observations of hadrons
Based on events collected with
the BESIII detector, five hadronic decays are searched for via process
. Three of them, ,
, and are observed for the first
time, with statistical significances of 7.4, , and
9.1, and branching fractions of ,
, and ,
respectively, where the first uncertainties are statistical and the second
systematic. No significant signal is observed for the other two decay modes,
and the corresponding upper limits of the branching fractions are determined to
be and at 90% confidence level.Comment: 17 pages, 16 figure
Measurements of Weak Decay Asymmetries of , , , and
Using production from a 567 pb
data sample collected by BESIII at 4.6 GeV, a full angular analysis is carried
out simultaneously on the four decay modes of , , , and . For the first time, the
transverse polarization is studied in unpolarized
collisions, where a non-zero effect is observed with a statistical significance
of 2.1. The decay asymmetry parameters of the weak
hadronic decays into , , and
are measured to be ,
,
, and
, respectively. In comparison with
previous results, the measurements for the and
modes are consistent but with improved precision, while the parameters for the
and modes are measured for the first time
Search for the decay
We search for radiative decays into a weakly interacting neutral
particle, namely an invisible particle, using the produced through the
process in a data sample of
decays collected by the BESIII detector
at BEPCII. No significant signal is observed. Using a modified frequentist
method, upper limits on the branching fractions are set under different
assumptions of invisible particle masses up to 1.2 . The upper limit corresponding to an invisible particle with zero mass
is 7.0 at the 90\% confidence level
Observation of and Improved Measurements of
Using a data sample corresponding to an integrated luminosity of
2.93~fb recorded by the BESIII detector at a center-of-mass energy of
GeV, we present an analysis of the decays and . By performing a partial wave
analysis, the -wave contribution to
is observed to be % with a statistical significance greater
than 10, besides the dominant -wave contribution. This is the first
observation of the -wave contribution. We measure the branching fractions
, , and . An upper limit
of is set at the 90% confidence level. We also obtain the hadronic
form factor ratios of at assuming the
single-pole dominance parameterization:
,
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