High-mass X-ray binaries and OB-runaway stars

High-mass X-ray binaries (HMXBs) represent an important phase in the evolution of massive binary systems. HMXBs provide unique diagnostics to test massive-star evolution, to probe the physics of radiation-driven winds, to study the process of mass accretion, and to measure fundamental parameters of compact objects. As a consequence of the supernova explosion that produced the neutron star (or black hole) in these systems, HMXBs have high space velocities and thus are runaways. Alternatively, OB-runaway stars can be ejected from a cluster through dynamical interactions. Observations obtained with the Hipparcos satellite indicate that both scenarios are at work. Only for a minority of the OB runaways (and HMXBs) a wind bow shock has been detected. This might be explained by the varying local conditions of the interstellar medium.Comment: 15 pages, latex (sty file included) with 5 embedded figures (one in jpg format), to appear in Proc. "Influence of binaries on stellar population studies", Eds. Vanbeveren, Van Rensberge

Polymorphisms in gene encoding TRPV1-receptor involved in pain perception are unrelated to chronic pancreatitis

Contains fulltext : 79505.pdf (publisher's version ) (Open Access

Cutoff value determines the performance of a semi-quantitative immunochemical faecal occult blood test in a colorectal cancer screening programme

BACKGROUND: The cutoff of semi-quantitative immunochemical faecal occult blood tests (iFOBTs) influences colonoscopy referrals and detection rates. We studied the performance of an iFOBT (OC-Sensor) in colorectal cancer (CRC) screening at different cutoffs. METHODS: Dutch screening participants, 50-75 years of age, with average CRC risk and an iFOBT value >or=50 ng ml(-1) were offered colonoscopy. The detection rate was the percentage of participants with CRC or advanced adenomas (>or=10 mm, >or=20% villous, high-grade dysplasia). The number needed to scope (NNTScope) was the number of colonoscopies to be carried out to find one person with CRC or advanced adenomas. RESULTS: iFOBT values >or=50 ng ml(-1) were detected in 526 of 6157 participants (8.5%) and 428 (81%) underwent colonoscopy. The detection rate for advanced lesions (28 CRC and 161 with advanced adenomas) was 3.1% (95% confidence interval: 2.6-3.5%) and the NNTScope was 2.3. At 75 ng ml(-1), the detection rate was 2.7%, the NNTScope was 2.0 and the CRC miss rate compared with 50 ng ml(-1) was <5% (N=1). At 100 ng ml(-1), the detection rate was 2.4% and the NNTScope was <2. Compared with 50 ng ml(-1), up to 200 ng ml(-1) CRC miss rates remained at 16% (N=4). CONCLUSIONS: Cutoffs below the standard 100 ng ml(-1) resulted in not only higher detection rates of advanced lesions but also more colonoscopies. With sufficient capacity, 75 ng ml(-1) might be advised; if not, up to 200 ng ml(-1) CRC miss rates are acceptable compared with the decrease in performed colonoscopies

Mutations Altering the Interplay between GkDnaC Helicase and DNA Reveal an Insight into Helicase Unwinding

Replicative helicases are essential molecular machines that utilize energy derived from NTP hydrolysis to move along nucleic acids and to unwind double-stranded DNA (dsDNA). Our earlier crystal structure of the hexameric helicase from Geobacillus kaustophilus HTA426 (GkDnaC) in complex with single-stranded DNA (ssDNA) suggested several key residues responsible for DNA binding that likely play a role in DNA translocation during the unwinding process. Here, we demonstrated that the unwinding activities of mutants with substitutions at these key residues in GkDnaC are 2–4-fold higher than that of wild-type protein. We also observed the faster unwinding velocities in these mutants using single-molecule experiments. A partial loss in the interaction of helicase with ssDNA leads to an enhancement in helicase efficiency, while their ATPase activities remain unchanged. In strong contrast, adding accessory proteins (DnaG or DnaI) to GkDnaC helicase alters the ATPase, unwinding efficiency and the unwinding velocity of the helicase. It suggests that the unwinding velocity of helicase could be modulated by two different pathways, the efficiency of ATP hydrolysis or protein-DNA interaction

Gastrointestinal Symptoms are Still Prevalent and Negatively Impact Health-Related Quality of Life: A Large Cross-Sectional Population Based Study in The Netherlands

Contains fulltext : 119280.pdf (publisher's version ) (Open Access)BACKGROUND: Over the last decades important risk factors for gastrointestinal symptoms have shifted, which may have changed its population prevalence. The aim of this study was to assess the current prevalence of gastrointestinal symptoms, appraise associated factors and assess health-related quality of life in the general population. METHODS: A total of 51,869 questionnaires were sent to a representative sample of the Dutch adult general population in December 2008. Demographic characteristics, gastrointestinal symptoms, health-related quality of life, medication use and co-morbidity were reported. We used multivariable logistic regression analysis to determine factors associated with gastrointestinal symptoms. RESULTS: A total of 18,317 questionnaires were returned, and 16,758 were eligible for analysis. Prevalence of gastrointestinal symptoms was 26%. Most frequent symptoms were bloating (63%), borborygmi (60%) and flatulence (71%). Female gender (adjusted OR (aOR) 1.59, 95% CI 1.43-1.77), asthma/COPD (aOR 1.47, 95% CI 1.21-1.79), use of paracetamol (aOR 1.33, 95% CI 1.20-1.47), antidepressants (aOR 1.56, 95% CI 1.22-2.00) and acid-suppressive medication were independently associated with presence of gastrointestinal symptoms. Age over 65 years (aOR 0.75, 95% CI 0.65-0.87), and use of statins (aOR 0.75, 95% CI 0.61-0.93) were associated with a lower prevalence of gastrointestinal symptoms. Respondents with gastrointestinal symptoms had a lower mean health-related quality of life of 0.81 (SD = 0.21) compared to 0.92 (SD = 0.14) for persons without gastrointestinal symptoms (P<0.01). CONCLUSIONS: Prevalence of gastrointestinal symptoms in the Dutch community is high and associated with decreased health-related quality of life

Efficacy of Helicobacter pylori eradication therapies: a single centre observational study

Background: Many Helicobacter pylori eradication regimens have been described. There are little data reporting their efficacy or integration in routine clinical practice. The overall results of eradication therapy in a cohort of patients are described and an algorithm for management outlined. Methods: 469 patients receiving eradication therapy in routine clinical practice were evaluated. The successes of individual regimes as first, second and third line therapy were determined. Results: Overall success after one, two and three courses of therapy were 73% (95% confidence intervals 69–77%), 94% (91–96%) and 98% (97–99%) respectively. 10 different regimens, including many non-recommended ones were used as primary therapy. Ranitidine bismuth citrate-amoxicillin-clarithromycin triple therapy (94.8%, 90–99%) was significantly more effective than any other combination as primary therapy, including all proton pump inhibitor based triple therapies. Quadruple therapy with bismuth chelate-proton pump inhibitor-tetracycline and a nitroimidazole (70%, 52–88%) and ranitidine bismuth citrate-based triple therapy (73%, 56–90%) where more effective second line combinations than proton pump inhibitor-triple therapies (37.5%, 12–58%). Third line therapy directed by the results of sensitivity testing improved eradication compared to further empirical antibiotics. The use of a proton pump inhibitor with clarithromycin and a nitroimidazole as initial therapy was associated with a significantly worse overall eradication rate than other combinations. Conclusions: Helicobacter pylori eradication rates can be maximised by using ranitidine bismuth citrate-clarithromycin-amoxicillin containing triple therapy, followed by bismuth and nitroimidazle containing second-line therapy, with third line combinations directed by sensitivity testing. Proton pump inhibitor-clarithromycin-metronidazole combinations should be avoided