Atomic data and electron-impact broadening effect in DO white dwarf atmospheres: Si VI

Energy levels, electric dipole transition probabilities and oscillator strengths in five times ionized silicon have been calculated in intermediate coupling. The present calculations were carried out with the general purpose atomic-structure program SUPERSTRUCTURE. The relativistic corrections to the non-relativistic Hamiltonian are taken into account through the Breit-Pauli approximation. We have also introduced a semi-empirical correction (TEC) for the calculation of the energy-levels. These atomic data are used to provide semiclassical electron-, proton- and ionized helium- impact line widths and shifts for 15 Si VI muliplet. Calculated results have been used to consider the influence of Stark broadening for DO white dwarf atmospheric conditions.Comment: MNRAS, accepted, 14 page

3D Coronal Density Reconstruction and Retrieving the Magnetic Field Structure during Solar Minimum

Measurement of the coronal magnetic field is a crucial ingredient in understanding the nature of solar coronal phenomena at all scales. We employed STEREO/COR1 data obtained during a deep minimum of solar activity in February 2008 (Carrington rotation CR 2066) to retrieve and analyze the three-dimensional (3D) coronal electron density in the range of heights from 1.5 to 4 Rsun using a tomography method. With this, we qualitatively deduced structures of the coronal magnetic field. The 3D electron density analysis is complemented by the 3D STEREO/EUVI emissivity in the 195 A band obtained by tomography for the same CR. A global 3D MHD model of the solar corona was used to relate the reconstructed 3D density and emissivity to open/closed magnetic field structures. We show that the density maximum locations can serve as an indicator of current sheet position, while the locations of the density gradient maximum can be a reliable indicator of coronal hole boundaries. We find that the magnetic field configuration during CR 2066 has a tendency to become radially open at heliocentric distances greater than 2.5 Rsun. We also find that the potential field model with a fixed source surface (PFSS) is inconsistent with the boundaries between the regions with open and closed magnetic field structures. This indicates that the assumption of the potential nature of the coronal global magnetic field is not satisfied even during the deep solar minimum. Results of our 3D density reconstruction will help to constrain solar coronal field models and test the accuracy of the magnetic field approximations for coronal modeling.Comment: Published in "Solar Physics

Protein profiling in hepatocellular carcinoma by label-free quantitative proteomics in two west african populations.

Background Hepatocellular Carcinoma is the third most common cause of cancer related death worldwide, often diagnosed by measuring serum AFP; a poor performance stand-alone biomarker. With the aim of improving on this, our study focuses on plasma proteins identified by Mass Spectrometry in order to investigate and validate differences seen in the respective proteomes of controls and subjects with LC and HCC. Methods Mass Spectrometry analysis using liquid chromatography electro spray ionization quadrupole time-of-flight was conducted on 339 subjects using a pooled expression profiling approach. ELISA assays were performed on four significantly differentially expressed proteins to validate their expression profiles in subjects from the Gambia and a pilot group from Nigeria. Results from this were collated for statistical multiplexing using logistic regression analysis. Results Twenty-six proteins were identified as differentially expressed between the three subject groups. Direct measurements of four; hemopexin, alpha-1-antitrypsin, apolipoprotein A1 and complement component 3 confirmed their change in abundance in LC and HCC versus control patients. These trends were independently replicated in the pilot validation subjects from Nigeria. The statistical multiplexing of these proteins demonstrated performance comparable to or greater than ALT in identifying liver cirrhosis or carcinogenesis. This exercise also proposed preliminary cut offs with achievable sensitivity, specificity and AUC statistics greater than reported AFP averages. Conclusions The validated changes of expression in these proteins have the potential for development into high-performance tests usable in the diagnosis and or monitoring of HCC and LC patients. The identification of sustained expression trends strengthens the suggestion of these four proteins as worthy candidates for further investigation in the context of liver disease. The statistical combinations also provide a novel inroad of analyses able to propose definitive cut-offs and combinations for evaluation of performance

Reactivity of pulmonary circulation and right ventricle function to inhaled nitric oxide in systemic sclerosis patients

Systemic sclerosis (SSc) is complicated by pulmonary hypertension and right ventricle (RV) failure in approximately 10% of the patients. Factors influencing the reactivity of pulmonary circulation to vasodilators are not established, while the examination of vasoreactivity is important in determining the treatment, because systemic administration of oral vasodilators can induce severe adverse events in nonresponders. The mechanism of RV failure in SSc is unclear and may result either from increased RV afterload or intrinsic myocardial disease. The aim of the study was to assess the reactivity of pulmonary circulation to inhaled nitric oxide (iNO) and to evaluate its influence on RV function in SSc patients with elevated right ventricle systolic pressure (RVSP). In 60 SSc patients aged 24–73 (58 females, two males; 33 patients with limited SSc and 27 with diffuse SSc), echocardiographic examination with tissue Doppler echocardiography (TDE) was performed. RV function was measured by systolic (S) and early diastolic (E) velocity of tricuspid annulus by TDE. In patients with RVSP >45 mmHg, the reactivity of pulmonary circulation was assessed by iNO test. High-resolution computerized tomography (HRCT) was performed to assess the extent of pulmonary fibrosis. Of 14 SSc subjects with elevated RVSP (13 females, one male; RVSP 47–62 mmHg), positive reaction to iNO was observed in five (RVSP decreased from 51.6 ± 3.7 to 32.24 ± 2.3 mmHg); nine patients were not reactive (RVSP 53.5 ± 5.7 mmHg before iNO vs. 49.6 ± 6.7 mmHg). RV systolic function was decreased in patients with elevated RVSP as compared to the patients with normal pulmonary pressure (S velocity 13.2 ± 1.3 vs. 14.4 ± 1.6 cm/s, respectively, p < 0.05). Significant increase of RV systolic function during iNO test was found in reactive patients only (S velocity before iNO 12.8 ± 1.2 cm/s, during iNO 14.5 ± 1.5 cm/s, p < 0.01). RVSP decrease strongly correlated with S velocity increase (r = 0.95, p < 0.0001). Response to iNO was found only in limited form of SSc; diffuse SSc patients showed no response. Pulmonary fibrosis on HRCT was more frequent in subjects nonreactive to iNO (67% of patients) than in the reactive group (40% of patients). The reactivity of pulmonary circulation to iNO in SSc patients with elevated RVSP was found predominantly in limited form of the disease. Pulmonary fibrosis typical for diffuse SSc was more frequent in nonreactive subjects. Elevated pulmonary pressure plays an important role in RV systolic dysfunction. Pulmonary pressure decrease during iNO test leads to the improvement of RV systolic function. Therapy for right-heart failure in reactive SSc patients should be directed, if possible, at the decrease in pulmonary resistance

The Reg3alpha (HIP/PAP) Lectin Suppresses Extracellular Oxidative Stress in a Murine Model of Acute Liver Failure

BACKGROUND AND AIMS: Acute liver failure (ALF) is a rapidly progressive heterogeneous illness with high mortality rate and no widely accessible cure. A promising drug candidate according to previous preclinical studies is the Reg3alpha (or HIP/PAP) lectin, which alleviates ALF through its free-radical scavenging activity. Here we study the therapeutic targets of Reg3alpha in order to gain information on the nature of the oxidative stress associated with ALF. METHODS: Primary hepatocytes stressed with the reactive oxygen species (ROS) inducers TNFalpha and H2O2 were incubated with a recombinant Reg3alpha protein. ALF was induced in C57BL/6J mice by an anti-CD95 antibody. Livers and primary hepatocytes were harvested for deoxycholate separation of cellular and extracellular fractions, immunostaining, immunoprecipitation and malondialdehyde assays. Fibrin deposition was studied by immunofluorescence in frozen liver explants from patients with ALF. RESULTS: Fibrin deposition occurs during experimental and clinical acute liver injuries. Reg3alpha bound the resulting transient fibrin network, accumulated in the inflammatory extracellular matrix (ECM), greatly reduced extracellular ROS levels, and improved cell viability. Hepatocyte treatment with ligands of death receptors, e.g. TNFalpha and Fas, resulted in a twofold increase of malondialdehyde (MDA) level in the deoxycholate-insoluble fractions. Reg3alpha treatment maintained MDA at a level similar to control cells and thereby increased hepatocyte survival by 35%. No antioxidant effect of Reg3alpha was noted in the deoxycholate-soluble fractions. Preventing fibrin network formation with heparin suppressed the prosurvival effect of Reg3alpha. CONCLUSIONS: Reg3alpha is an ECM-targeted ROS scavenger that binds the fibrin scaffold resulting from hepatocyte death during ALF. ECM alteration is an important pathogenic factor of ALF and a relevant target for pharmacotherapy

The crystal structure of the TetR family transcriptional repressor SimR bound to DNA and the role of a flexible N-terminal extension in minor groove binding

SimR, a TetR-family transcriptional regulator (TFR), controls the export of simocyclinone, a potent DNA gyrase inhibitor made by Streptomyces antibioticus. Simocyclinone is exported by a specific efflux pump, SimX and the transcription of simX is repressed by SimR, which binds to two operators in the simR-simX intergenic region. The DNA-binding domain of SimR has a classical helix-turn-helix motif, but it also carries an arginine-rich N-terminal extension. Previous structural studies showed that the N-terminal extension is disordered in the absence of DNA. Here, we show that the N-terminal extension is sensitive to protease cleavage, but becomes protease resistant upon binding DNA. We demonstrate by deletion analysis that the extension contributes to DNA binding, and describe the crystal structure of SimR bound to its operator sequence, revealing that the N-terminal extension binds in the minor groove. In addition, SimR makes a number of sequence-specific contacts to the major groove via its helix-turn-helix motif. Bioinformatic analysis shows that an N-terminal extension rich in positively charged residues is a feature of the majority of TFRs. Comparison of the SimR–DNA and SimR–simocyclinone complexes reveals that the conformational changes associated with ligand-mediated derepression result primarily from rigid-body rotation of the subunits about the dimer interface

Trends in prevalence of hepatitis B virus infection among Albanian blood donors, 1999-2009

<p>Abstract</p> <p>Background</p> <p>Hepatitis B virus (HBV) was among the first virus known to be transmitted by blood and blood productions. The objective of this study is to determine the trend of hepatitis B virus in blood donors.</p> <p>Materials and methods</p> <p>In this study 79274 blood donors were retrospectively evaluated for HBsAg. The donors were selected using personal questionnaire, physical examination and testing blood before donation. Blood banks records are used as source of information. The blood donors samples were analyzed for the presence of hepatitis B surface antigen (HBsAg) by commercial available kits ELISA method, third generation (from Abbott laboratory, Germany). A sample was considered as HBsAg positive when found twice repeatedly reactive. Reactive samples were not confirmed with addition tests.</p> <p>Results</p> <p>In the evaluation data, we found out that from 79274 of the total healthy blood donors, 15983 were voluntary donors, 52876 were family replacement donors and 10424 commercial blood donors. The prevalence of HBsAg in blood donors was 7.9%. It was increased steadily from 5.9% in 1999 to 9.1% in 2006 and decreased in 7.9% in 2009. According to blood donors status the HBsAg prevalence was 10.5% in commercial blood donors, 8.1% in voluntary donors and 8.6% in family replacement donors. The prevalence of anti-HBc in blood donors was 59.1%.</p> <p>Conclusion</p> <p>The prevalence of HBsAg was lower in voluntary non remunerate blood donors than commercial donors and family replacement blood donors. In FDs the prevalence was higher than VDs but lower than CDs. So, it is important to encourage the voluntary blood donors to become regularly blood donors.</p