Improving accuracy of quantifying nitrate removal performance and enhancing understanding of processes in woodchip bioreactors using high-frequency data

Woodchip bioreactors have gained popularity in many countries as a conservation practice for reducing nitrate load to freshwater. However, current methods for assessing their performance may be inadequate when nitrate removal rates (RR) are determined from low-frequency (e.g., weekly) concurrent sampling at the inlet and outlet. We hypothesised that high-frequency monitoring data at multiple locations can help improve the accuracy of quantifying nitrate removal performance, enhance the understanding of processes occurring within a bioreactor, and therefore improve the design practice for bioreactors. Accordingly, the objectives of this study were to compare RRs calculated using high- and low-frequency sampling and assess the spatiotemporal variability of the nitrate removal within a bioreactor to unravel the processes occurring within a bioreactor. For two drainage seasons, we monitored nitrate concentrations at 21 locations on an hourly or two-hourly basis within a pilot-scale woodchip bioreactor in Tatuanui, New Zealand. A novel method was developed to account for the variable lag time between entry and exit of a parcel of sampled drainage water. Our results showed that this method not only enabled lag time to be accounted for but also helped quantify volumetric inefficiencies (e.g., dead zone) within the bioreactor. The average RR calculated using this method was significantly higher than the average RR calculated using conventional low-frequency methods. The average RRs of each of the quarter sections within the bioreactor were found to be different. 1-D transport modelling confirmed the effect of nitrate loading on the removal process as nitrate reduction followed Michaelis-Menten (MM) kinetics. These results demonstrate that high-frequency temporal and spatial monitoring of nitrate concentrations in the field allows improved description of bioreactor performance and better understanding of processes occurring within woodchip bioreactors. Thus, insights gained from this study can be used to optimise the design of future field bioreactors.

Knock down analysis reveals critical phases for specific oskar noncoding RNA functions during Drosophila oogenesis

The oskar transcript, acting as a noncoding RNA, contributes to a diverse set of pathways in the Drosophila ovary, including karyosome formation, positioning of the microtubule organizing center (MTOC), integrity of certain ribonucleoprotein particles, control of nurse cell divisions, restriction of several proteins to the germline, and progression through oogenesis. How oskar mRNA acts to perform these functions remains unclear. Here, we use a knock down approach to identify the critical phases when oskar is required for three of these functions. The existing transgenic shRNA for removal of oskar mRNA in the germline targets a sequence overlapping a regulatory site bound by Bruno1 protein to confer translational repression, and was ineffective during oogenesis. Novel transgenic shRNAs targeting other sites were effective at strongly reducing oskar mRNA levels and reproducing phenotypes associated with the absence of the mRNA. Using GAL4 drivers active at different developmental stages of oogenesis, we found that early loss of oskar mRNA reproduced defects in karyosome formation and positioning of the MTOC, but not arrest of oogenesis. Loss of oskar mRNA at later stages was required to prevent progression through oogenesis. The noncoding function of oskar mRNA is thus required for more than a single event.

Left atrial scar burden in sinus rhythm differs from atrial fibrillation using automated voltage analysis during radiofrequency ablation for atrial fibrillation

Funding Acknowledgements

Type of funding sources: None.

Introduction

Scar burden in atrial fibrillation (AF) can be overestimated due to many factors. Scar burden has prognostic value and substrates considered for ablation by some electrophysiologists. We compared left atrial (LA) scar voltage in AF to sinus rhythm (SR) using voltage histogram analysis (VHA) of those undergoing pulmonary vein isolation (PVI) for persistent AF (PeAF). We believe this is the first study analysing LA scar location in SR and AF using VHA.

Methods

We retrospectively analysed 120 anatomical segments (AS) and whole LA voltages (N= 10 patients, mean age 68 ± 7, 4 females) in SR and AF. Fast anatomical maps (FAM) were grouped into 6 AS in AF and SR: Anterior, Posterior, Roof, Floor, Septal and Lateral AS, which were analysed via VHA (Figure 1) in 10 voltage ranges between 0mV-0.5mV. Total LA area in each voltage aliquot was recorded in SR and AF, taking diseased LA as 0.2-0.5mV and dense LA scar as <0.2mV. The pulmonary veins, mitral annulus and trans-septal puncture sites were excluded from analyses. We included patients over age 18 with PeAF who had de novo PVI with no extra ablation lines, maps with >1000 voltage points in both rhythms and uniform procedure involving initial mapping in AF then remapping in SR after PVI. Statistical analyses conducted with IBM SPSS v.26.

Results

Total LA scar burden was greater in AF (Mean 142.76 mm², SD ± 138.78mm²) than SR (Mean 109mm², SD ± 107.8mm²), p= <0.0001, Table 1. Scar correlation in SR and AF had a good relationship, R = 0.416 (p= <0.001). Every 1mm² of scar identified during SR yielded a mean of 1.54mm² in AF, (p= <0.001).

Conclusions

AF was associated with higher scar burden in the Roof, Anterior, Lateral and Posterior AS. Dense LA scar (≤ 0.2mV) on the Posterior AS was significantly higher in AF, while in other AS was comparable to SR. Mapping substrate in AF, especially the posterior wall, may be misleading as scar burden may be overestimated when compared to SR. Table 1Voltage< 0.02 mV (mean area ± SD mm2)0.2-0.5mV (mean area mm2)RhythmSRAFp-valueSRAFp-valueEntire LA115.89 ± 113.61143.41 ± 144.230.02*105.78 ± 103.73144.00 ± 135.24<0.0001*Roof82.72 ± 117.3283.68 ± 113.560.95115 ± 77.14150.61 ± 93.170.01*Anterior131.8 ± 169.53126.5 ± 154.570.85158.53 ± 99.22220.87 ± 173.070.002*Lateral70.5 ± 80.0090.57 ± 117.990.3687.52 ± 66.82137.05 ± 104.990.0002*Septal80.99 ± 89.0380.99 ± 89.030.6899.123 ± 73.62115.37 ± 84.830.18Floor105.1 ± 134.91106.42 ± 148.670.96117.62 ± 85.41151.2 ± 110.070.052Posterior102.14 ± 157.47159.03 ± 194.650.02*138.27 ± 112.28234 ± 150.45<0.0001*LA scar distribution in SR and AF, *denotes significant results.Abstract Figure 1

Different roles for the adjoining and structurally similar A-rich and poly(A) domains of oskar mRNA: Only the A-rich domain is required for oskar noncoding RNA function, which includes MTOC positioning

Drosophila oskar (osk) mRNA has both coding and noncoding functions, with the latter required for progression through oogenesis. Noncoding activity is mediated by the osk 3' UTR. Three types of cis elements act most directly and are clustered within the final ~120 nucleotides of the 3' UTR: multiple binding sites for the Bru1 protein, a short highly conserved region, and A-rich sequences abutting the poly(A) tail. Here we extend the characterization of these elements and their functions, providing new insights into osk noncoding RNA function and the makeup of the cis elements. We show that all three elements are required for correct positioning of the microtubule organizing center (MTOC), a defect not previously reported for any osk mutant. Normally, the MTOC is located at the posterior of the oocyte during previtellogenic stages of oogenesis, and this distribution underlies the strong posterior enrichment of many mRNAs transported into the oocyte from the nurse cells. When osk noncoding function was disrupted the MTOC was dispersed in the oocyte and osk mRNA failed to be enriched at the posterior, although transport to the oocyte was not affected. A previous study did not detect loss of posterior enrichment for certain osk mutants lacking noncoding activity (Kanke et al., 2015). This discrepancy may be due to use of imaging aimed at monitoring transport to the oocyte rather than posterior enrichment. Involvement in MTOC positioning suggests that the osk noncoding function may act in conjunction with genes whose loss has similar effects, and that osk function may extend to other processes requiring those genes. Further characterization of the cis elements required for osk noncoding function included completion of saturation mutagenesis of the most highly conserved region, providing critical information for evaluating the possible contribution of candidate binding factors. The 3'-most cis element is a cluster of A-rich sequences, the ARS. The close juxtaposition and structural similarity of the ARS and poly(A) tail raised the possibility that they comprise an extended A-rich element required for osk noncoding function. We found that absence of the poly(A) tail did not mimic the effects of mutation of the ARS, causing neither arrest of oogenesis nor mispositioning of osk mRNA in previtellogenic stage oocytes. Thus, the ARS and the poly(A) tail are not interchangeable for osk noncoding RNA function, suggesting that the role of the ARS is not in recruitment of Poly(A) binding protein (PABP), the protein that binds the poly(A) tail. Furthermore, although PABP has been implicated in transport of osk mRNA from the nurse cells to the oocyte, mutation of the ARS in combination with loss of the poly(A) tail did not disrupt transport of osk mRNA into the oocyte. We conclude that PABP acts indirectly in osk mRNA transport, or is associated with osk mRNA independent of an A-rich binding site. Although the poly(A) tail was not required for osk mRNA transport into the oocyte, its absence was associated with a novel osk mRNA localization defect later in oogenesis, potentially revealing a previously unrecognized step in the localization process.

Ethical challenges experienced by researchers in community-based participatory research

Background

Political, economic and climate events continue to bring the dismantling of communities and creation of new ones. Understanding successful models of adaptation and working with communities to address their health and wellbeing needs requires ethically sound public health research. Community-Based Participatory Research (CBPR) has been proposed as an equitable, empowering partnership approach to collaborative health research that encapsulates analysis, advocacy and action for the future wellbeing of communities. Meanwhile, a strong interest in ethical implications of CBPR continues in international literature, yet with a notable lack of research that captures the experience of researchers who had ethical challenges in their CBPR studies. The aim of this research was to address this lack of evidence by exploring those experiences of CBPR researchers internationally.

Methods

An innovative data collection method was designed utilising a purpose-built blog. This internet-based, qualitative online study enabled asynchronous international data collection on the blog. Participants were researchers with experience of CBPR and were recruited through social media platforms. Blog narratives of first-hand experiences of CBPR researchers were analysed using thematic analysis.

Results

The themes that emerged from blog data analysis were researchers' challenges with balancing participant protection and autonomy, dealing with partnership tensions, and the enduring impacts on the researchers.

Conclusions

This study enhances our understanding of ethical challenges in CBPR with evidence of enduring impacts on researchers of the 'tightrope' they walked in the interests of maintaining research integrity and ethical responsibility towards their partnering communities. Challenges arose largely from complexities of CBPR coupled with rigid regulatory structures of human research ethics review that struggles to respond adequately in the interests of communities and researchers.

Key messages

At this critical time for the future of humanity, communities can benefit from CBPR. A positive way forward for ethical review of CBPR exists for those with power to make a difference.

Deep-water fisheries along the British Isles continental slopes: status, ecosystem effects and future perspectives

In this paper, we revisit the state of deep-water fisheries to the west of the British Isles and aim to provide an overview on the key drivers behind community changes along continental margins. The deep-water fisheries to the west of the British Isles that extend from the shelf-slope break down to the lower slope and along banks and seamounts of the Rockall Basin, mainly target blue ling Molva dypterygia, roundnose grenadier Coryphaenoides rupestris, orange roughy Hoplostethus atlanticus, with by-catches of black scabbardfish Aphanopus carbo and tusk Brosme brosme. These fishing grounds experienced a long period of exhaustive exploitation until the early 2000s, but subsequently the implementation of management strategies has helped to relieve excessive fishing pressure. It is widely accepted that a better understanding of the long-term implications of disturbance is needed to understand patterns in deep-water communities and what sustainable use and exploitation of resources might look like in this context.

Cost Implications of Reactive Versus Prospective Testing for Dihydropyrimidine Dehydrogenase Deficiency in Patients With Colorectal Cancer: A Single-Institution Experience

Background:

Severe toxicity is experienced by a substantial minority of patients receiving fluoropyrimidine-based chemotherapy, with approximately 20% of these severe toxicities attributable to polymorphisms in the DPYD gene. The DPYD codes for the enzyme dihydropyrimidine dehydrogenase (DPD) important in the metabolism of fluoropyrimidine-based chemotherapy. We questioned whether prospective DPYD mutation analysis in all patients commencing such therapy would prove more cost-effective than reactive testing of patients experiencing severe toxicity.

Methods:

All patients experiencing severe toxicity from fluoropyrimidine-based chemotherapy for colorectal cancer in an Irish private hospital over a 3-year period were tested for 4 DPYD polymorphisms previously associated with toxicity. The costs associated with an index admission for toxicity in DPD-deficient patients were examined. A cost analysis was undertaken comparing the anticipated cost of implementing screening for DPYD mutations versus current usual care. One-way sensitivity analysis was conducted on known input variables. An alternative scenario analysis from the perspective of the Irish health-care payer (responsible for public hospitals) was also performed.

Results:

Of 134 patients commencing first-line fluoropyrimidine chemotherapy over 3 years, 30 (23%) patients developed grade 3/4 toxicity. Of these, 17% revealed heterozygote DPYD mutations. The cost of hospitalization for the DPYD-mutated patients was €232 061, while prospectively testing all 134 patients would have cost €23 718. Prospective testing would result in cost savings across all scenarios.

Conclusions:

The cost of hospital admission for severe chemotherapy-related toxicity is significantly higher than the cost of prospective DPYD testing of each patient commencing fluoropyrimidine chemotherapy.

A challenging redox neutral Cp*Co(III)-catalysed alkylation of acetanilides with 3-buten-2-one: synthesis and key insights into the mechanism through DFT calculations

Traditional, established palladium cross-coupling procedures are widely applied in complex molecule synthesis; however, there is a significant disadvantage in the requirement for pre-functionalised substrates (commonly halides/triflates). Direct C–H activation protocols provide the opportunity for a novel approach to synthesis, although this field is still in its relative infancy and often transferability between substrate classes remains unresolved and limitations not fully understood. This study focuses on the translation of an established Cp*Co(III)-catalysed alkylation of benzamides to related acetanilides using 3-buten-2-one as coupling partner. The developed procedure provides a wide substrate scope in terms of substituted acetanilides, although the optimised conditions were found to be more forcing than those for the corresponding benzamide substrates. Interestingly, density functional theory (DFT) studies reveal that the major impediment in the mechanism is not the C–H activation step, but instead and unexpectedly, effective competition with more stable compounds (resting states) not involved in the catalytic cycle.

Supervised toothbrushing programs in primary schools and early childhood settings: A scoping review

OBJECTIVE

In this article we report the findings of a scoping review that aimed to identify and summarise the range of programs and guidelines available for toothbrushing programs in schools and early childhood settings. Dental caries is one of the most common preventable diseases affecting children worldwide. Untreated caries can impact on child health and wellbeing, development, socialisation and school attendance. Supervised toothbrushing programs in schools and other early childhood settings can be effective in improving the oral health of young children. There is limited understanding of the salient issues to consider when developing such programs or how they are best implemented in real world settings.

METHODS

A scoping review methodology was utilised to provide a summary of the guidelines and programs available. Key search terms were developed, mapped and utilised to identify guidelines and programs across 6 databases and key search engines.

RESULTS

We located 26 programs and guidelines that met the inclusion and exclusion criteria for the review. These were collated and summarised across key countries and critical aspects of program development and implementation were identified. Toothbrush type and storage, toothpaste strength and method of dispensing, toothbrush storage, staff training and parental consent are key considerations that varied widely.

CONCLUSIONS AND RECOMMENDATIONS

Guidelines for supervised toothbrushing programs vary within and across countries due to differences in water fluoridation and availability of low fluoride toothpastes. The results of this review provide critical information to be considered when establishing and implementing toothbrushing programs in these settings.

Multiple cis-acting signals, some weak by necessity, collectively direct robust transport of oskar mRNA to the oocyte

Localization of mRNAs can involve multiple steps, each with its own cis-acting localization signals and transport factors. How is the transition between different steps orchestrated? We show that the initial step in localization of Drosophila oskar mRNA - transport from nurse cells to the oocyte - relies on multiple cis-acting signals. Some of these are binding sites for the translational control factor Bruno, suggesting that Bruno plays an additional role in mRNA transport. Although transport of oskar mRNA is essential and robust, the localization activity of individual transport signals is weak. Notably, increasing the strength of individual transport signals, or adding a strong transport signal, disrupts the later stages of oskar mRNA localization. We propose that the oskar transport signals are weak by necessity; their weakness facilitates transfer of the oskar mRNA from the oocyte transport machinery to the machinery for posterior localization.

The economic implications of changing regulations for deep sea fishing under the European Common Fisheries Policy: UK case study

Economic impact assessment methodology was applied to UK fisheries data to better understand the implications of European Commission proposal for regulations to fishing for deep-sea stocks in the North-East Atlantic (EC COM 371 Final 2012) under the Common Fisheries Policy (CFP). The aim was to inform the on-going debate to develop the EC proposal, and to assist the UK fishing industry and Government in evaluating the most effective options to manage deep sea fish stocks. Results indicate that enforcing the EC proposal as originally drafted results in a number of implications for the UK fleet. Because of the proposed changes to the list of species defined as being deep sea species, and a new definition of what constitutes a vessel targeting deep sea species, a total of 695 active UK fishing vessels would need a permit to fish for deep sea species. However, due to existing and capped capacity limits many vessels would potentially not be able to obtain such a permit. The economic impact of these changes from the status quo reveals that in the short term, landings would decrease by 6540 tonnes, reducing gross value added by £3.3 million. Alternative options were also assessed that provide mitigation measures to offset the impacts of the proposed regulations whilst at the same time providing more effective protection of deep sea Vulnerable Marine Ecosystems (VMEs). The options include setting a 400m depth rule that identifies a depth beyond which vessels would potentially be classified as fishing for deep sea species and designating 'core areas' for deep sea fishing at depths>400m to minimise the risk of further impacts of bottom fishing gear on deep sea habitats. Applying a 400m depth limit and 'core fishing' area approach deeper than 400m, the impact of the EC proposal would essentially be reduced to zero, that is, on average no vessels (using the status quo capacity baseline) would be impacted by the proposal.

Community effects in regulation of translation

Certain forms of translational regulation, and translation itself, rely on long-range interactions between proteins bound to the different ends of mRNAs. A widespread assumption is that such interactions occur only in cis, between the two ends of a single transcript. However, certain translational regulatory defects of the Drosophila oskar (osk) mRNA can be rescued in trans. We proposed that inter-transcript interactions, promoted by assembly of the mRNAs in particles, allow regulatory elements to act in trans. Here we confirm predictions of that model and show that disruption of PTB-dependent particle assembly inhibits rescue in trans. Communication between transcripts is not limited to different osk mRNAs, as regulation imposed by cis-acting elements embedded in the osk mRNA spreads to gurken mRNA. We conclude that community effects exist in translational regulation.

DOI:http://dx.doi.org/10.7554/eLife.10965.001

Genes encode the instructions needed to make proteins and other molecules. To make a protein, the DNA within a gene is copied to produce molecules of messenger ribonucleic acid (mRNA) that are then used as templates to build proteins via a process called translation. This process – which involves protein machines called ribosomes binding to the start of the mRNA – is tightly regulated to control the amounts of particular proteins in cells. For example, in fruit fly ovaries, a protein called Bruno both represses and activates the translation of a gene known as oskar. To achieve this, Bruno binds to regions near the end of the oskar RNA known as Bruno response elements.

It is not clear how Bruno acts to control translation. However, because ribosomes begin translation near the start of the mRNA, while Bruno is bound to regions near the end of the mRNA, there must be long-range interactions between the two ends of the mRNA. It is generally assumed that such long-range interactions only occur between proteins that are bound to the same mRNA molecule. However, in 2010, researchers observed that Bruno response elements within one oskar mRNA could influence the translation of other oskar mRNAs. This is known as “regulation in trans”. Here, Macdonald et al. – including some of the researchers from the earlier work – investigated this observation in more detail in fruit flies.

In cells, multiple mRNA molecules and their associated proteins can assemble into particles. Macdonald et al. proposed that the close proximity of many mRNA molecules in these particles could allow trans regulation to take place. Indeed, the experiments found that blocking the assembly of oskar mRNA into particles inhibited trans regulation as expected. Macdonald et al. also asked if trans regulation can occur between mRNAs that encode different proteins. The experiments show that oskar mRNA could block the translation of an mRNA produced by the gurken gene, even when oskar mRNA was not being translated. More work is needed to find out how widely trans regulation is used to control translation.

DOI:http://dx.doi.org/10.7554/eLife.10965.002

Kernel density surface modelling as a means to identify significant concentrations of vulnerable marine ecosystem indicators

The United Nations General Assembly Resolution 61/105, concerning sustainable fisheries in the marine ecosystem, calls for the protection of vulnerable marine ecosystems (VME) from destructive fishing practices. Subsequently, the Food and Agriculture Organization (FAO) produced guidelines for identification of VME indicator species/taxa to assist in the implementation of the resolution, but recommended the development of case-specific operational definitions for their application. We applied kernel density estimation (KDE) to research vessel trawl survey data from inside the fishing footprint of the Northwest Atlantic Fisheries Organization (NAFO) Regulatory Area in the high seas of the northwest Atlantic to create biomass density surfaces for four VME indicator taxa: large-sized sponges, sea pens, small and large gorgonian corals. These VME indicator taxa were identified previously by NAFO using the fragility, life history characteristics and structural complexity criteria presented by FAO, along with an evaluation of their recovery trajectories. KDE, a non-parametric neighbour-based smoothing function, has been used previously in ecology to identify hotspots, that is, areas of relatively high biomass/abundance. We present a novel approach of examining relative changes in area under polygons created from encircling successive biomass categories on the KDE surface to identify “significant concentrations” of biomass, which we equate to VMEs. This allows identification of the VMEs from the broader distribution of the species in the study area. We provide independent assessments of the VMEs so identified using underwater images, benthic sampling with other gear types (dredges, cores), and/or published species distribution models of probability of occurrence, as available. For each VME indicator taxon we provide a brief review of their ecological function which will be important in future assessments of significant adverse impact on these habitats here and elsewhere.

Returning home: psychosocial care during the re-entry phase of cancer survivorship in rural Australia

The purpose of this research was to highlight gaps in formal psychosocial care for cancer survivors in rural communities. The study was conducted in rural Victoria, Australia, and involved interviews with people with various stages of cancer progression, cancer diagnoses and survival times, who were interviewed about their experiences of psychosocial cancer care. Interviews focused on their experience of psychosocial care and were audio-recorded and transcribed verbatim. Data were thematically analysed to identify key themes. Findings demonstrate that psychosocial care is essentially informal within the re-entry period after cancer diagnosis and treatment. Despite current Australian clinical guidelines on psychosocial care for people with cancer, which indicate the need for the provision of formal psychosocial care, participants in this study largely cared for themselves, or received informal support from family, friends and community members. Many psychosocial needs remained unmet and professional support was lacking. While this study was conducted in rural Australia, many of our findings have been echoed in studies from other countries. The findings have implications for treatment protocols and discharge planning, health professional-patient-family relationships, and the long-term well-being of cancer survivors living in rural communities. A model for understanding the experience of formal supportive care during the re-entry phase of survivorship is proposed.

Cost implications of reactive versus prospective testing for dihydropyrimidine dehydrogenase (DPD) deficiency in patients with colorectal cancer

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Background: DPD is an enzyme encoded by the DPYD gene involved in the metabolism of the chemotherapy drug 5-fluorouracil (5FU) and the oral 5FU prodrug capecitabine. Patients (pts) with DPYD mutations are at risk of severe toxicities from standard dose 5FU, although they may safely receive lower dose therapy with careful monitoring and dose escalation. Methods: In this retrospective study we identified all pts starting 5FU-based chemotherapy for colorectal cancer (CRC) at our institution between Jan 1 2010 and Dec 31 2012. During this time DPD testing was usually performed in a reactive manner, typically for pts experiencing severe toxicities. We reviewed the charts of pts who tested positive for DPYD mutations and assessed the financial implications of their hospitalizations with toxicity. These costs were compared to the costs which would have incurred if all pts starting such therapy had been proactively tested. Results: A total of 134 pts started first-line 5FU-based chemotherapy for CRC over the study period, 66 in the adjuvant setting and 68 for metastatic disease. 31 pts had DPYD mutation testing performed. 6 tests (19% of those tested, 4.5% of the total population) revealed heterozygote DPYD mutations. 5 pts had already experienced severe treatment-related toxicity resulting in cessation of therapy, while one was tested prospectively and received chemotherapy with dose reduction ab initio. The total cost related to hospitalization with toxicity for these 5 pts was €155,083. At €177 per test, the cost to prospectively test all pts starting first-line 5FU-based therapy over the time period would have been €23,718 representing a saving of €131,365 through avoiding these admissions alone. 4 pts who tested positive for DPYD mutations were receiving adjuvant therapy and none restarted therapy following severe toxicity early in their therapy. 2 pts subsequently relapsed with metastatic disease. Conclusions: Prospective testing for DPYD mutations in pts with CRC starting 5FU-based therapy for the first time represents a considerable cost-saving opportunity, in addition to potentially avoiding prolonged hospitalization and morbidity for a sizeable minority of pts.

Weaning onto solid foods: some of the challenges

Weaning--the transition from milk to solid food--influences life-long health. Dietary challenges during weaning include providing sufficient critical nutrients such as iron with minimal added sugar and fat and no added salt. This study assessed the inclusion of iron-containing red meat in infant diets before age one year, and the Irish commercial baby food environment. Of mothers with an infant under 30 months of age who were surveyed in shopping centres in Ireland (n195), 82% (n159) reported wanting more weaning information. A quarter (n24) of infants over age 12 months (n97) received no iron-containing red meat before age one year. A scan of commercial baby foods in Ireland identified 448 products. While all complied with baby food legislation, 15% (n69) were intrinsically high in sugar and fat, or contained added salt. This study indicates the need for specific guidance on best infant feeding practice in Ireland.

Towards the development of integrated epilepsy services: an audit of documented epilepsy care

Effective chronic disease management (CDM) requires the ready availability and communication of accurate, clinical disease specific information. Using epilepsy as a probe into CDM, we report on the availability and reliability of clinical information in the primary care records of people with epilepsy (PWE). The medical records of 374 PWE from 53 general practices in the Mid-West region of Ireland were examined. Confirmation of an epilepsy diagnosis by a neurologist was documented for 132 (35%) patients. 282 (75%) patients had no documented evidence of receiving specialist neurology review while 149 (40%) had not been reviewed by their GP in the previous two years for their epilepsy. Significant variation in documentation of epilepsy specific information together with an inadequacy and inconsistency of existing epilepsy services was highlighted.

Detection of myocardial viability by dobutamine stress echocardiography: incremental value of diastolic wall thickness measurement

OBJECTIVE

To assess the diagnostic accuracy of baseline diastolic wall thickness (DWT) alone and as an adjunct to dobutamine stress echocardiography (DSE) for prediction of myocardial viability in patients with ischaemic left ventricular (LV) dysfunction, with the recovery of resting function after revascularisation as the yardstick.

PATIENTS

24 patients with ischaemic LV dysfunction (ejection fraction < 40%) scheduled for surgical revascularisation.

SETTING

Regional cardiothoracic centre.

METHODS

All patients underwent DSE before and resting echocardiography six months after revascularisation. DWT was measured in each of the 16 LV segments. A receiver operating characteristic (ROC) and a multi-ROC curve were generated to assess the ability of DWT alone and in combination with DSE to predict myocardial viability.

RESULTS

DWT > 0.6 cm provided a sensitivity of 80%, a specificity of 51%, and a negative predictive value of 80% for the prediction of viability in akinetic segments. DSE had an excellent specificity (92%) but a modest sensitivity (60%) in akinetic segments. A combination of improvement at DSE or DWT > 0.8 cm improved sensitivity (90% v 60%, p < 0.001) and negative predictive value (92% v 78%, p = 0.03) in akinetic segments compared with DSE alone. This was achieved with some loss in specificity (75% v 92%, p = 0.01) and positive predictive value (71% v 82%, p = 0.79).

CONCLUSIONS

DWT measurement may improve the sensitivity of DSE for the detection of myocardial viability. Akinetic segments with DWT > 0.8 cm have a good chance of recovery despite the absence of contractile reserve during DSE. Further testing may be required before excluding myocardial viability in these cases.

Drosophila klarsicht has distinct subcellular localization domains for nuclear envelope and microtubule localization in the eye

The Drosophila klarsicht (klar) gene is required for developmentally regulated migrations of photoreceptor cell nuclei in the eye. klar encodes a large ( approximately 250 kD) protein with only one recognizable amino acid sequence motif, a KASH (Klar, Anc-1, Syne-1 homology) domain, at its C terminus. It has been proposed that Klar facilitates nuclear migration by linking the nucleus to the microtubule organizing center (MTOC). Here we perform genetic and immunohistochemical experiments that provide a critical test of this model. We analyze mutants in the endogenous klar gene and also flies that express deleted forms of Klar protein from transgenes. We find that the KASH domain of Klar is critical for perinuclear localization and for function. In addition, we find that the N-terminal portion of Klar is also important for function and contains a domain that localizes the protein to microtubules apical to the nucleus. These results provide strong support for a model in which Klar links the nucleus to the MTOC.

Direct monitoring of soil and water nitrate by FTIR based FEWS or membrane systems

The development of silver halide fibers that transmit with minimal loss into the mid-IR (MIR) paved the way to their successful utilization as effective ATR (Attenuated Total Reflectance) elements, promoting the implementation of Fiberoptic Evanescent Wave Spectroscopy (FEWS) for direct monitoring of nitrate in environmental systems. Samples containing nitrate in water, soil extracts, and pastes were used for the determination of nitrate concentration with a common ATR ZnSe crystal and with silver halide fibers (FEWS). Spectra of soil pastes and suspensions and those of phosphate, carbonate, sulfate, ammonium, and soil organic constituents were collected to study possible interference with nitrate determination. The standard error of estimate (SEE) and R2 values obtained with flat fibers, using the simple single-point correlation method, were superior to those obtained for cylindrical FEWS and ZnSe ATR crystals in pure water. A significant improvement in the SEE and R2 was achieved in most soil pastes by applying the simple mode of the Cross Correlation method. Direct transmission of MIR radiation through ion-exchange membranes, partially loaded with nitrate or carbonate, was found an effective alternative for MIR-FTIR determination of these ions. Further development and modification of the FEWS devices should allow in-situ and online determination of nitrate in soil and environmental systems.

Surface integration of velocity vectors from 3D digital colour Doppler: an angle independent method for laminar flow measurements

BACKGROUND

The study was designed to test the angle independence of a dynamic three-dimensional digital colour Doppler method for laminar flow measurement. The technique acquired three-dimensional data by rotational acquisition and used surface integration of Doppler vector velocities and flow areas in time and space for flow computation.

METHOD

A series of pulsatile flows (peak flow 55-180 ml/s) through a curved tube were studied with reference flow rates obtained using an ultrasonic flow meter. Colour Doppler imaging was performed at three angles to the direction of flow (20 degrees, 30 degrees, 40 degrees), using a multiplane transoesophageal probe controlled by an ATL HDI5000 system. Integration of digital velocity vectors over a curved three-dimensional surface across the tube for each of the 11 flow rates at each angle was performed off-line to compute peak flow.

RESULTS

Peak flow rates correlated closely (r=0.99) with the flow meter with the mean difference from the reference being -0.8+/-2 x 4 ml/s, 0.9+/-2.6 ml/s, 1.0+/-2 x 3 ml/s for 20 degrees, 30 degrees and 40 degrees respectively. Comparison of the three angle groups showed no significant differences (P=0.15, ANOVA). When sampled obliquely, the flow area on the curved surface increased while the velocities measured decreased.

CONCLUSION

Surface integration of velocity vectors to compute three-dimensional Doppler flow data is less angle dependent than conventional Doppler methods.

Dobutamine stress echocardiography for the detection of myocardial viability in patients with left ventricular dysfunction taking beta blockers: accuracy and optimal dose

OBJECTIVE

To assess the accuracy of dobutamine stress echocardiography (DSE) and the optimal dose of dobutamine to detect myocardial viability in patients with ischaemic left ventricular (LV) dysfunction who are taking beta blockers, using the recovery of function six months artery revascularisation as the benchmark.

PATIENTS

17 patients with ischaemic LV dysfunction (ejection fraction < 40%) and chronic treatment with beta blockers scheduled to undergo surgical revascularisation.

SETTING

Regional cardiothoracic centre.

METHODS

All patients underwent DSE one week before and resting echocardiography six months after revascularisation. A wall motion score was assigned to each segment for each dobutamine infusion stage, using the standard 16 segment model of the left ventricle. The accuracy of DSE to predict recovery of resting segmental function was calculated for low dose (5 and 10 microg/kg/min) and for a full protocol of dobutamine infusion (5 to 40 microg/kg/min).

RESULTS

Of the 272 segments studied, 158 (58%) were dysfunctional at rest, of which 79 (50%) improved at DSE and 74 (47%) recovered resting function after revascularisation. Analysis of results with a low dose showed a significantly lower sensitivity and negative predictive value than with a full protocol (47% v 81%, p < 0.001 and 65% v 82%, p < 0.05, respectively). The accuracy in the full protocol analysis was comparable with that reported in patients no longer taking beta blockers but was significantly lower than that in the low dose analysis (78% v 66%, p < 0.001).

CONCLUSIONS

Findings suggest that beta blocker withdrawal is not necessary before DSE when viability is the clinical information in question. However, a completed protocol with continuous image recording is required to detect the full extent of viability.