236 research outputs found
On the scent of sexual attraction
A study in the current issue of BMC Biology has identified a mouse major urinary protein as a pheromone that attracts female mice to male urine marks and induces a learned attraction to the volatile urinary odor of the producer. See research article http://www.biomedcentral.com/1741-7007/8/7
Human peritoneal mesothelial cells respond to bacterial ligands through a specific subset of Toll-like receptors
Background. Bacterial infection remains a major cause of morbidity and mortality in peritoneal dialysis (PD) patients worldwide. Previous studies have identified a key role for mesothelial cells, lining the peritoneal cavity, in coordinating inflammation and host defense. Toll-like receptor (TLR) involvement in early activation events within the mesothelium, however, remains poorly defined. To investigate the initiation of bacterial peritonitis, we characterized TLR activation by bacterial ligands in human peritoneal mesothelial cells (HPMC)
Hepatobiliary phenotypes of adults with alpha-1 antitrypsin deficiency
OBJECTIVE: Alpha-1 antitrypsin deficiency (AATD) is a common, potentially lethal inborn disorder caused by mutations in alpha-1 antitrypsin (AAT). Homozygosity for the 'Pi*Z' variant of AAT (Pi*ZZ genotype) causes lung and liver disease, whereas heterozygous 'Pi*Z' carriage (Pi*MZ genotype) predisposes to gallstones and liver fibrosis. The clinical significance of the more common 'Pi*S' variant remains largely undefined and no robust data exist on the prevalence of liver tumours in AATD. DESIGN: Baseline phenotypes of AATD individuals and non-carriers were analysed in 482â380 participants in the UK Biobank. 1104 participants of a multinational cohort (586 Pi*ZZ, 239 Pi*SZ, 279 non-carriers) underwent a comprehensive clinical assessment. Associations were adjusted for age, sex, body mass index, diabetes and alcohol consumption. RESULTS: Among UK Biobank participants, Pi*ZZ individuals displayed the highest liver enzyme values, the highest occurrence of liver fibrosis/cirrhosis (adjusted OR (aOR)=21.7 (8.8-53.7)) and primary liver cancer (aOR=44.5 (10.8-183.6)). Subjects with Pi*MZ genotype had slightly elevated liver enzymes and moderately increased odds for liver fibrosis/cirrhosis (aOR=1.7 (1.2-2.2)) and cholelithiasis (aOR=1.3 (1.2-1.4)). Individuals with homozygous Pi*S mutation (Pi*SS genotype) harboured minimally elevated alanine aminotransferase values, but no other hepatobiliary abnormalities. Pi*SZ participants displayed higher liver enzymes, more frequent liver fibrosis/cirrhosis (aOR=3.1 (1.1-8.2)) and primary liver cancer (aOR=6.6 (1.6-26.9)). The higher fibrosis burden was confirmed in a multinational cohort. Male sex, age â„50âyears, obesity and the presence of diabetes were associated with significant liver fibrosis. CONCLUSION: Our study defines the hepatobiliary phenotype of individuals with the most relevant AATD genotypes including their predisposition to liver tumours, thereby allowing evidence-based advice and individualised hepatological surveillance
Measurement of the inclusive and dijet cross-sections of b-jets in pp collisions at sqrt(s) = 7 TeV with the ATLAS detector
The inclusive and dijet production cross-sections have been measured for jets
containing b-hadrons (b-jets) in proton-proton collisions at a centre-of-mass
energy of sqrt(s) = 7 TeV, using the ATLAS detector at the LHC. The
measurements use data corresponding to an integrated luminosity of 34 pb^-1.
The b-jets are identified using either a lifetime-based method, where secondary
decay vertices of b-hadrons in jets are reconstructed using information from
the tracking detectors, or a muon-based method where the presence of a muon is
used to identify semileptonic decays of b-hadrons inside jets. The inclusive
b-jet cross-section is measured as a function of transverse momentum in the
range 20 < pT < 400 GeV and rapidity in the range |y| < 2.1. The bbbar-dijet
cross-section is measured as a function of the dijet invariant mass in the
range 110 < m_jj < 760 GeV, the azimuthal angle difference between the two jets
and the angular variable chi in two dijet mass regions. The results are
compared with next-to-leading-order QCD predictions. Good agreement is observed
between the measured cross-sections and the predictions obtained using POWHEG +
Pythia. MC@NLO + Herwig shows good agreement with the measured bbbar-dijet
cross-section. However, it does not reproduce the measured inclusive
cross-section well, particularly for central b-jets with large transverse
momenta.Comment: 10 pages plus author list (21 pages total), 8 figures, 1 table, final
version published in European Physical Journal
Co-Housing Rodents with Different Coat Colours as a Simple, Non-Invasive Means of Individual Identification:Validating Mixed-Strain Housing for C57BL/6 and DBA/2 Mice
Standard practice typically requires the marking of laboratory mice so that they can be individually identified. However, many of the common methods compromise the welfare of the individuals being marked (as well as requiring time, effort, and/or resources on the part of researchers and technicians). Mixing strains of different colour within a cage would allow them to be readily visually identifiable, negating the need for more invasive marking techniques. Here we assess the impact that mixed strain housing has on the phenotypes of female C57BL/6 (black) and DBA/2 (brown) mice, and on the variability in the data obtained from them. Mice were housed in either mixed strain or single strain pairs for 19 weeks, and their phenotypes then assessed using 23 different behavioural, morphological, haematological and physiological measures widely used in research and/or important for assessing mouse welfare. No negative effects of mixed strain housing could be found on the phenotypes of either strain, including variables relevant to welfare. Differences and similarities between the two strains were almost all as expected from previously published studies, and none were affected by whether mice were housed in mixed- or single-strain pairs. Only one significant main effect of housing type was detected: mixed strain pairs had smaller red blood cell distribution widths, a measure suggesting better health (findings that now need replicating in case they were Type 1 errors resulting from our multiplicity of tests). Furthermore, mixed strain housing did not increase the variation in data obtained from the mice: the standard errors for all variables were essentially identical between the two housing conditions. Mixed strain housing also made animals very easy to distinguish while in the home cage. Female DBA/2 and C57BL/6 mice can thus be housed in mixed strain pairs for identification purposes, with no apparent negative effects on their welfare or the data they generate. This suggests that there is much value in exploring other combinations of strains
Low Luminosity Type II Supernovae: Spectroscopic and Photometric Evolution
In this paper we present spectroscopic and photometric observations for four
core collapse supernovae (SNe), namely SNe 1994N, 1999br, 1999eu and 2001dc.
Together with SN 1997D, we show that they form a group of exceptionally
low-luminosity events. These SNe have narrow spectral lines (indicating low
expansion velocities) and low luminosities at every phase (significantly lower
than those of typical core-collapse supernovae). The very low luminosity during
the ^{56}Co radioactive decay tail indicates that the mass of ^{56}Ni ejected
during the explosion is much smaller (M(Ni) ~ 2-8 x 10^{-3} Mo) than the
average (M(Ni) ~ 6-10 x 10^{-2} Mo). Two supernovae of this group (SN 1999br
and SN 2001dc) were discovered very close to the explosion epoch, allowing us
to determine the lengths of their plateaux (~ 100 days) as well as
establishiing the explosion epochs of the other, less-completely observed SNe.
It is likely that this group of SNe represent the extreme low-luminosity tail
of a single continuous distribution of SN II-P events. Their kinetic energy is
also exceptionally low. Although an origin from low mass progenitors has also
been proposed for low-luminosity core-collapse SNe, recent work provides
evidence in favour of the high mass progenitor scenario. The incidence of these
low--luminosity SNe could be as high as 4-5 of all type II SNe.Comment: 23 pages, 26 figures, accepted for publication in MNRA
- âŠ