High resolution visualisation of tiemannite microparticles, essential in the detoxification process of mercury in marine mammals

The North Sea is an ecologically rich habitat for marine wildlife which has also been impacted by industrial developments and anthropogenic emissions of contaminants such as mercury. Marine mammals are particularly susceptible to mercury exposure, due to their trophic position, long lifespan, and dependence on (increasingly contaminated) aquatic prey species. To mitigate impact, marine mammals can detoxify methylmercury by binding it to selenium-containing biomolecules, creating insoluble mercury selenide granules. Here, liver, kidney, muscle, and brain samples from an adult male bottlenose dolphin (Tursiops truncatus) with known elevated mercury concentrations were analysed through scanning electron microscopy (SEM). Tiemannite (HgSe) deposits were identified in all organs, ranging from 400 nm to 5 μm in diameter, with particle size being organ-dependent. Although reported in other studies, this is the first time that the three-dimensional nature of tiemannite is captured in marine mammal tissue.

The Living with Dysarthria group for post-stroke dysarthria: the participant voice

BACKGROUND

The Living with Dysarthria group programme, devised for people with post-stroke dysarthia and family members, was piloted twice. Feedback from those who experience an intervention contributes to the evaluation of speech and language therapy programmes, giving the participant view of the intervention's value and guiding further developments.

RESEARCH QUESTION

What feedback do participants in the Living with Dysarthria programme provide, informing on its perceived usefulness and guiding its future development?

METHODS & PROCEDURES

Nine people with chronic dysarthria following stroke and four family members who completed the Living with Dysarthria programme all contributed to Focus Group (FG) discussion, transcribed and thematically analysed, and completed an Anonymous Questionnaire Evaluation (AQE), comprising closed statements and open questions. An anonymous descriptive adjective selection task (ADAST) was also used.

OUTCOMES & RESULTS

The varied forms of feedback provided complementary information. Thematic analysis of FG data and AQE open question responses were configured around programme benefits, programme structure and content, and programme practicalities. Benefits associated with participation included learning and insight, being supported by peers and professionals, and improved speech and confidence. These are consistent with the main programme elements of education, support and speech practice. All activities were seen as relevant and positively received. Flexibility, recognition of and catering to individual needs were valued characteristics. The community location was approved by all. Most participants thought the format of eight weekly sessions of 2 h was appropriate. Responses to AQE closed statements provided almost unanimous confirmation of the very positive feedback conveyed in FG discussions. The main response to suggested improvements in AQEs was that the number of sessions should be increased. Feedback indicated that for a few individuals there was negative reaction to some facts about stroke, home practice tasks were difficult to complete, the person with dysarthria/family member pair may not be the optimum combination for paired practice activities and pre-programme information should be extended. The ADAST showed that the programme was enjoyable, interesting, stimulating and useful.

CONCLUSIONS & IMPLICATIONS

Participant feedback indicates that group therapy, with family member participation, is a valid form of management for chronic post-stroke dysarthria. Education, peer and professional support, and speech practice are confirmed as relevant programme components. Consistent majority opinions were communicated in different situations and via varied mediums. Some individuals expressed views relevant to their own needs, and these responses also inform future implementation of the Living with Dysarthria programme.

Fugacity modelling to predict the distribution of organic contaminants in the soil:oil matrix of constructed biopiles

Level I and II fugacity approaches were used to model the environmental distribution of benzene, anthracene, phenanthrene, 1-methylphenanthrene and benzo[a]pyrene in a four phase biopile system, accounting for air, water, mineral soil and non-aqueous phase liquid (oil) phase. The non-aqueous phase liquid (NAPL) and soil phases were the dominant partition media for the contaminants in each biopile and the contaminants differed markedly in their individual fugacities. Comparison of three soils with different percentage of organic carbon (% org C) showed that the % org C influenced contaminant partitioning behaviour. While benzene showed an aqueous concentration worthy of note for leachate control during biopiling, other organic chemicals showed that insignificant amount of chemicals leached into the water, greatly reducing the potential extent of groundwater contamination. Level II fugacity model showed that degradation was the dominant removal process except for benzene. In all three biopile systems, the rate of degradation of benzo(a)pyrene was low, requiring more than 12 years for soil concentrations from a spill of about 25 kg (100 mol) to be reduced to a concentration of 0.001 microgg(-1). The removal time of 1-methylphenanthrene and either anthracene or phenanthrene was about 1 and 3 years, respectively. In contrast, benzene showed the highest degradation rate and was removed after 136 days in all biopile systems. Overall, this study confirms the association of risk critical contaminants with the residual saturation in treated soils and reinforces the importance of accounting for the partitioning behaviour of both NAPL and soil phases during the risk assessment of oil-contaminated sites.

Comparison of different microbial bioassays to assess metal-contaminated soils

These experiments compared the sensitivity of four different types of bioassay over time after five metals were added to a wide range of soils at the maximum concentrations in the European Union Sewage Sludge Directive. Three were chronic assays (most probable number of Rhizobium leguminosarum, soil microbial C and Biolog substrate utilization). The fourth bioassay, an acute biosensor, employed a lux-marked luminescent bacterium (Escherichia coli) in the soil pore water. Five metals were added to 23 different soils as a mixture at Zn = 300, Cd = 3, Pb = 300, Cu = 135, and Ni = 75 mg/kg as nitrate salts and compared with unamended controls. Zinc and Cu were the metals most likely to be toxic at the concentrations used here. In the case of Rhizobium, the number of cells in soil was not affected after 11 d; however, by 818 d the numbers had decreased by four orders of magnitude with increasing concentrations of Zn and Cu in soil solution. Microbial biomass also was not affected after 11 d, but significantly decreased with increased Zn (p < 0.001) and Cu (p < 0.01) in soil solution after 818 d. Toxicity to the soil microbial biomass increased with time, whereas the toxicity to the biosensor remained the same. Biolog substrate utilization profiles were not responsive to the concentrations used here.

Prophylactic subcutaneous heparin does not increase operative blood loss in transurethral resection of the prostate

A prospective randomised study of subcutaneous heparin compared with no heparin was performed in 60 patients undergoing transurethral resection of the prostate. Operative blood loss in the irrigation fluid was measured using a haemoglobinometer. Blood loss correlated with the amount of prostate resected and the duration of the procedure. Subcutaneous heparin had no significant effect on the measured blood loss in transurethral resection of the prostate and can be used as a safe means of prophylaxis against thrombo-embolic complications.

A model for predicting parasitic gastroenteritis in lambs subject to mixed nematode infections

A model previously developed for the prediction of parasitic gastroenteritis in lambs arising from infection by the nematode parasite Ostertagia circumcincta has been adapted to consider mixed infection and retested. The importance of the lambs as a contributing source to the summer wave of infective larvae is highlighted as are certain apparent deficiencies in the use of grass sampling techniques as a means of assessing pasture larval contamination.

Forecasting parasitic gastroenteritis in lambs

Incorporating estimated temperature data and assuming non-limiting rainfall, a simulation model was used to compare forecast and actual pasture counts of sheep nematode larvae over a 2-year period. The results indicate that the first possible date of the summer larval rise can be predicted up to 6 weeks in advance of its actual occurrence, enabling control measures to be planned and implemented. Rainfall variation had a marked effect on the degree of disparity between the predicted and actual timing of the rise, indicating the importance of this factor.

The application of a simulation model to control strategies in ovine gastro-intestinal parasitism

A simulation model which describes the pattern of increase in Ostertagia circumcincta infective larvae on pasture grazed by ewes and lambs, was used to test the effect of anthelmintic treatment at different times in the grazing season. Treatment generally resulted in a delay in the rise to peak larval count, and marked differences were recorded in two successive years, which were related to a combination of time of treatment and weather conditions.