The role of DMQ(9) in the long-lived mutant clk-1

IntroductionUbiquinone (UQ) is a redox active lipid that transfers electrons from complex I or II to complex III in the electron transport chain (ETC). The long-lived Caenorhabditis elegans mutant clk-1 is unable to synthesize its native ubiquinone, and accumulates high amounts of its precursor, 5-demethoxyubiquinone-9 (DMQ₉). In clk-1, complexes I–III activity is inhibited while complexes II–III activity is normal. We asked whether the complexes I–III defect in clk-1 was caused by: (1) a defect in the ETC; (2) an inhibitory effect of DMQ₉; or (3) a decreased amount of ubiquinone.MethodsWe extracted the endogenous quinones from wildtype (N2) and clk-1 mitochondria, replenished them with exogenous ubiquinones, and measured ETC activities.ResultsReplenishment of extracted mutant and wildtype mitochondria resulted in equal enzymatic activities for complexes I–III and II–III ETC assays. Blue native gels showed that supercomplex formation was indistinguishable between clk-1 and N2. The addition of a pentane extract from clk-1 mitochondria containing DMQ₉ to wildtype mitochondria specifically inhibited complexes I–III activity. UQ in clk-1 mitochondria was oxidized compared to N2.DiscussionOur results show that no measurable intrinsic ETC defect exists in clk-1 mitochondria. The data indicate that DMQ₉ specifically inhibits electron transfer from complex I to ubiquinone.     

Severe Maternal Morbidity in Canada: Temporal Trends and Regional Variations, 2003-2016

ObjectiveThis study sought to quantify temporal trends and provincial and territorial variations in severe maternal morbidity (SMM) in Canada.MethodsThe study used data on all hospital deliveries in Canada (excluding Québec) from 2003 to 2016 to examine temporal trends and from 2012 to 2016 to study regional variations. SMM was identified using diagnosis and intervention codes. Contrasts among periods and regions were quantified using rate ratios (RRs) and 95% confidence intervals (CIs). Temporal changes were also assessed using chi-square tests for trend (Canadian Task Force Classification II-1).ResultsThe study population included 3 882 790 deliveries between 2003 and 2016 and 1 418 545 deliveries between 2012 and 2016. Severe hemorrhage rates increased from 44.8 in 2003 to 62.4 per 10 000 deliveries in 2012 (P for trend <0.0001) and then declined to 41.8 per 10 000 deliveries in 2016 (P for trend <0.0001). Maternal intensive care unit admission and sepsis rates decreased between 2003 and 2016, whereas rates of stroke, severe uterine rupture, hysterectomy, obstetric embolism, shock, and assisted ventilation increased. Rates of composite SMM in 2012-2016 were higher in Newfoundland and Labrador (RR 1.15; 95% CI 1.04–1.26), Nova Scotia (RR 1.11; 95% CI 1.03–1.19), New Brunswick (RR1.22; 95% CI 1.13–1.32), Manitoba (RR 1.09; 95% CI 1.03–1.15), Saskatchewan (RR 1.15; 95% CI 1.09–1.22), the Yukon (RR 1.74; 95% CI 1.35–2.25), and Nunavut (RR 1.76; 95% CI 1.46–2.11) compared with the rest of Canada, whereas rates were lower in Alberta and British Columbia.ConclusionThis surveillance report helps inform clinical practice and public health policy for improving maternal health in Canada.     

A case of maternal tetanus in Korea

Tetanus is uncommon in Korea due to the introduction of vaccination programs and advances in public health. A case of maternal tetanus occurred on the 9 day postpartum in a 29-yr-old woman, who had not received a 10-yr-booster of tetanus-diphtheria toxoid after receiving the primary series of tetanus-toxoid-containing vaccine. There has hitherto been no reports on maternal tetanus in Korea. This case illustrates that tetanus remains a medical problem, principally among non- and under-immunized adults. The only way to fully prevent this disease is to ensure adequate immunization in all adults.     

Participatory action research,mixed methods,and research teams: learning from philosophically juxtaposed methodologies for optimal research outcomes

Background

Workplace health interventions incorporating qualitative and quantitative components (mixed methods) within a Participatory Action Research approach can increase understanding of contextual issues ensuring realistic interventions which influence health behaviour. Mixed methods research teams, however, face a variety of challenges at the methodological and expertise levels when designing actions and interventions. Addressing these challenges can improve the team’s functionality and lead to higher quality health outcomes. In this paper we reflect on the data collection, implementation and data analysis phases of a mixed methods workplace health promotion project and discuss the challenges which arose within our multidisciplinary team.

Methods

This project used mixed methods within a Participatory Action Research approach to address workers’ sun safety behaviours in 14 outdoor workplaces in Queensland, Australia, and elucidate why certain measures succeeded (or failed) at the worker and management level. The project integrated qualitative methods such as policy analysis and interviews, with a range of quantitative methods – including worker surveys, ultraviolet radiation (UVR) exposure measurement, and implementation cost analyses.

Results

The research team found the integration of qualitative and quantitative analyses within the Participatory Action Research process to be challenging and a cause of tensions. This had a negative impact on the data analysis process and reporting of results, and the complexity of qualitative analysis was not truly understood by the quantitative team. Once all researchers recognised qualitative and quantitative data would be equally beneficial to the Participatory Action Research process, methodological bias was overcome to a degree to which the team could work cooperatively.

Conclusions

Mixed methods within a Participatory Action Research approach may allow a research team to discuss, reflect and learn from each other, resulting in broadened perspectives beyond the scope of any single research methodology. However, cohesive and supportive teams take constant work and adjustment under this approach, as knowledge and understanding is gained and shared. It is important researchers are cognisant of, and learn from, potential tensions within research teams due to juxtaposed philosophies, methodologies and experiences, if the team is to function efficiently and positive outcomes are to be achieved.

     

Performance of Reperfusion Therapy and Hospital Mortality in ST-Elevation Myocardial Infarction Patients with Non-Chest Pain Complaints

Purpose

ST-elevation myocardial infarction (STEMI) patients may visit the emergency department (ED) complaining of sensations of pain other than the chest. We investigated our performance of reperfusion therapy for STEMI patients presenting with non-chest pains.

Materials and Methods

This was a retrospective observational cohort study. STEMI patients who underwent primary percutaneous coronary intervention (PCI) were divided into a chest pain group and a non-chest pain group. Clinical differences between the two groups and the influence of presenting with non-chest pains on door-to-electrocardiograms (ECG) time, door-to-balloon time, and hospital mortality were evaluated.

Results

Of the 513 patients diagnosed with STEMI, 93 patients presented with non-chest pains. Patients in the non-chest pain group were older, more often female, and had a longer symptom onset to ED arrival time and higher Killip class than patients in the chest pain group. There was a statistically significant delay in door-to-ECG time (median, 2.0 min vs. 5.0 min; p<0.001) and door-to-balloon time (median, 57.5 min vs. 65.0 min; p<0.001) in patients without chest pain. In multivariate analysis, presenting with non-chest pains was an independent predictor for hospital mortality (odds ratio, 2.3; 95% confidence interval, 1.1-4.7). However, door-to-ECG time and door-to-balloon time were not factors related to hospital mortality.

Conclusion

STEMI patients presenting without chest pain showed higher baseline risk and hospital mortality than patients presenting with chest pain. ECG acquisition and primary PCI was delayed for patients presenting with non-chest pains, but not influencing hospital mortality. Efforts to reduce pre-hospital time delay for these patients are necessary.     

Triblock copolymer based thermoplastic elastomeric gels of a large service temperature range: preparation and characterization

Poly(methyl methacrylate)-block-polybutadiene-block-poly(methyl methacrylate) (MBM) triblock copolymers and their hydrogenated counterparts with poly(ethylene-co-1,2-butylene) midblock (MEBM) were swollen by an aliphatic oil of high boiling point which is a selective solvent for the central block. Thermoreversible gels are accordingly formed by both MBM and MEBM copolymers above a critical polymer content (Cr), which depends on the nature of the midblock and not on the copolymer molecular weight, at least in the investigated range. Cr has been found to be 5 wt.-% for an MBM block copolymer and 2 wt.-% for MEBM copolymers of various molecular weights. Gels of MEBM triblock copolymers exhibit interesting mechanical properties, such as high elongation at break (up to 870%) and high tensile strength (32 kPa). The most interesting feature of the MEBM gels is an upper service temperature as high as 170°C, thus more than 100°C higher than the value (47°C) reported for gels of an SEBS copolymer (S = polystyrene) of comparable molecular weight (100000) and composition (ca. 30 wt.-% hard block). The morphology of MEBM gels was studied by scanning electron microscopy (SEM) and found to be cocontinuous in case of a gel containing 20 wt.-% copolymer.     

Awareness of the risk of endocarditis associated with tattooing and body piercing among patients with congenital heart disease and paediatric cardiologists in the United Kingdom.

Body art in the form of tattoos and piercing has become increasingly popular amongst children and teenagers, and is nowadays more socially acceptable despite media reports citing tissue destruction and death. Our study explored the awareness and experience of patients with congenital heart disease, and of cardiologists and professionals responsible for their care.