Anaerobic oxidation of methane associated with sulfate reduction in a natural freshwater gas source

The occurrence of anaerobic oxidation of methane (AOM) and trace methane oxidation (TMO) was investigated in a freshwater natural gas source. Sediment samples were taken and analyzed for potential electron acceptors coupled to AOM. Long-term incubations with 13C-labeled CH4 (13CH4) and different electron acceptors showed that both AOM and TMO occurred. In most conditions, 13C-labeled CO2 (13CO2) simultaneously increased with methane formation, which is typical for TMO. In the presence of nitrate, neither methane formation nor methane oxidation occurred. Net AOM was measured only with sulfate as electron acceptor. Here, sulfide production occurred simultaneously with 13CO2 production and no methanogenesis occurred, excluding TMO as a possible source for 13CO2 production from 13CH4. Archaeal 16S rRNA gene analysis showed the highest presence of ANME-2a/b (ANaerobic MEthane oxidizing archaea) and AAA (AOM Associated Archaea) sequences in the incubations with methane and sulfate as compared with only methane addition. Higher abundance of ANME-2a/b in incubations with methane and sulfate as compared with only sulfate addition was shown by qPCR analysis. Bacterial 16S rRNA gene analysis showed the presence of sulfate-reducing bacteria belonging to SEEP-SRB1. This is the first report that explicitly shows that AOM is associated with sulfate reduction in an enrichment culture of ANME-2a/b and AAA methanotrophs and SEEP-SRB1 sulfate reducers from a low-saline environment.We thank Douwe Bartstra (Vereniging tot Behoud van de Gasbronnen in Noord-Holland, The Netherlands), Carla Frijters (Paques BV, The Netherlands) and Teun Veuskens (Laboratory of Microbiology, WUR, The Netherlands) for sampling; Martin Meirink (Hoogheemraadschap Hollands Noorderkwartier, The Netherlands) for physicochemical data; Freek van Sambeek for providing Figure 1; Lennart Kleinjans (Laboratory of Microbiology, WUR, The Netherlands) for help with pyrosequencing analysis, Irene Sánchez-Andrea (Laboratory of Microbiology, WUR, The Netherlands) for proof-reading and Katharina Ettwig (Department of Microbiology, Radboud University Nijmegen, The Netherlands) for providing M. oxyfera DNA. We want to thank all anonymous reviewers for valuable contributions. This research is supported by the Dutch Technology Foundation STW (project 10711), which is part of the Netherlands Organization for Scientific Research (NWO), and which is partly funded by the Ministry of Economic Affairs. Research of AJMS is supported by ERC grant (project 323009) and the Gravitation grant (project 024.002.002) of the Netherlands Ministry of Education, Culture and Science and the Netherlands Science Foundation (NWO)

Consultation performance of general practitioners when supported by an asthma/COPDC-service

<p>Abstract</p> <p>Background</p> <p>General practitioners (GPs) can refer patients to an asthma/COPD service (AC-service) for diagnostic assessment of spirometry and medical history and for asthma or COPD monitoring. The AC-service reports diagnostic results and additional information about disease burden (BORG-score for complaints, MRC-dyspnoea score, exacerbation rate), life style, medication and compliance, to the patient’s GP. This study explores how GPs use this additional information when discussing the patient’s disease burden and how this influences GPs’ information and education provision during consultations with asthma/COPD patients.</p> <p>Method</p> <p>Patients with (a suspicion of) asthma or COPD were referred to an AC-service and consulted their GPs after they had received a report from the AC-service. Retrospectively patients answered questions about their GPs’ performance during these consultations. Performances were compared with performances of the same GPs during consultations without support of the AC-service (usual care), earlier that year.</p> <p>Results</p> <p>Of consultations not initiated by an AC-service check-up, 91% focussed on complaints, the initial reason for the consultation. In AC-service supported follow-up consultations, GPs explored disease burden when the (BORG-)score for complaints was high - as reported by the AC-service - even when patients themselves thought it was irrelevant. GPs put significantly less effort in exploring disease burden when the Borg-score was low (BORG 3–4: 69%; BORG1-2: 51%, <it>p = 0,01</it>). GPs mostly ignored MRC-dyspnoea scores: attention to dyspnoea was 18% for MRC-score <3 and 25% for MRC-score ≥3 (<it>p = 0,63).</it> GPs encouraged physical fitness in 13% of patients. Smoking behaviour was discussed with 66% of the actual smokers but only 14% remembered a stop smoking advice. Furthermore, pharmacotherapeutic management education in AC-service supported consultations did not differ from performance in usual care according to patient evaluations.</p> <p>Conclusion</p> <p>Other than taking into account the severity of complaints, there was no difference between GPs’ performance in AC-service supported and in usual care consultations. AC-service reports are thus not effective by themselves. GPs should be encouraged to use the information better and systematically check all relevant aspects that characterize the disease burden of their patients.</p

Leukemia and brain tumors among children after radiation exposure from CT scans: design and methodological opportunities of the Dutch Pediatric CT Study

Computed tomography (CT) scans are indispensable in modern medicine; however, the spectacular rise in global use coupled with relatively high doses of ionizing radiation per examination have raised radiation protection concerns. Children are of particular concern because they are more sensitive to radiation-induced cancer compared with adults and have a long lifespan to express harmful effects which may offset clinical benefits of performing a scan. This paper describes the design and methodology of a nationwide study, the Dutch Pediatric CT Study, regarding risk of leukemia and brain tumors in children after radiation exposure from CT scans. It is a retrospective record-linkage cohort study with an expected number of 100,000 children who received at least one electronically archived CT scan covering the calendar period since the introduction of digital archiving until 2012. Information on all archived CT scans of these children will be obtained, including date of examination, scanned body part and radiologist's report, as well as the machine settings required for organ dose estimation. We will obtain cancer incidence by record linkage with external databases. In this article, we describe several approaches to the collection of data on archived CT scans, the estimation of radiation doses and the assessment of confounding. The proposed approaches provide useful strategies for data collection and confounder assessment for general retrospective record-linkage studies, particular those using hospital databases on radiological procedures for the assessment of exposure to ionizing or non-ionizing radiation