Hypoxia determines survival outcomes of bacterial infection through HIF-1alpha dependent re-programming of leukocyte metabolism

Hypoxia and bacterial infection frequently co-exist, in both acute and chronic clinical settings, and typically result in adverse clinical outcomes. To ameliorate this morbidity, we investigated the interaction between hypoxia and the host response. In the context of acute hypoxia, both S. aureus and S. pneumoniae infections rapidly induced progressive neutrophil mediated morbidity and mortality, with associated hypothermia and cardiovascular compromise. Preconditioning animals through longer exposures to hypoxia, prior to infection, prevented these pathophysiological responses and profoundly dampened the transcriptome of circulating leukocytes. Specifically, perturbation of HIF pathway and glycolysis genes by hypoxic preconditioning was associated with reduced leukocyte glucose utilisation, resulting in systemic rescue from a global negative energy state and myocardial protection. Thus we demonstrate that hypoxia preconditions the innate immune response and determines survival outcomes following bacterial infection through suppression of HIF-1α and neutrophil metabolism. The therapeutic implications of this work are that in the context of systemic or tissue hypoxia therapies that target the host response could improve infection associated morbidity and mortality.

Tube-side mass transfer for hollow fibre membrane contactors operated in the low Graetz range

Transformation of the tube-side mass transfer coefficient derived in hollow fibre membrane contactors (HFMC) of different characteristic length scales (equivalent diameter and fibre length) has been studied when operated in the low Graetz range (Gz<10). Within the low Gz range, mass transfer is generally described by the Graetz problem (Sh=3.67) which assumes that the concentration profile comprises a constant shape over the fibre radius. In this study, it is experimentally evidenced that this assumption over predicts mass transfer within the low Graetz range. Furthermore, within the low Gz range (below 2), a proportional relationship between the experimentally determined mass transfer coefficient (K_ov) and the Graetz number has been identified. For Gz numbers below 2, the experimental Sh number approached unity, which suggests that mass transfer is strongly dependent upon diffusion. However, within this diffusion controlled region of mass transfer, tube-side fluid velocity remained important. For Gz numbers above 2, Sh could be satisfactorily described by extension to the Lévêque solution, which can be ascribed to the constrained growth of the concentration boundary layer adjacent to the fibre wall. Importantly this study demonstrates that whilst mass transfer in the low Graetz range does not explicitly conform to either the Graetz problem or classical Lévêque solution, it is possible to transform the experimentally derived overall mass transfer coefficient (K_ov) between characteristic length scales (d_h and L). T_his was corroborated by comparison of the empirical relationship determined in this study (Sh=0.36Gz) with previously published studies operated in the low Gz range. This analysis provides important insight for process design when slow tube-side flows, or low Schmidt numbers (coincident with gases) constrain operation of hollow fibre membrane contactors to the low Gz range.

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For the low Graetz range (<2), a proportional relationship between Sh and Gz is found.

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For Gz<2, Sh depends on diffusion but fluid velocity remains important.

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For Gz numbers above 2, Sh satisfactorily described by extension to Lévêque.

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Experimental K_ov can be transformed between length scales (d_h and L) at low Gz.

The implementation of a transanal endoscopic microsurgery programme: initial experience with surgical performance

AIM

Despite transanal endoscopic microsurgery (TEM) being used for over 30 years, there has been slow adoption of this modality in many centres. There remains a paucity of research regarding the learning curve and early performance of surgeons who begin to offer TEM. We sought to determine predictors of longer rates of tumour excision and improvements in operative time in a newly established TEM programme.

METHOD

All patients who underwent TEM at the Ottawa Hospital, Ottawa, Canada, between October 2009 and September 2014 were included. Data were abstracted through a retrospective chart review. The average rate of lesion excision (ARE) was calculated to standardize the operation time by size of the pathological specimen (min/cm³ ), representing a measure of surgical efficiency. Surgical efficiency was plotted using restricted cubic splines. Predictors of higher ARE were determined using multivariable regression.

RESULTS

During the study period 108 patients underwent TEM. ARE was available for 95 patients of mean age 67.2 years. The mean ARE was 18.6 min/cm³ . On adjusting for important covariates, the ARE improved with each additional case until 16 cases were completed. Significant predictors of higher ARE on multivariable analysis were age < 50 years, experience of fewer than five cases, and carcinoid/gastrointestinal stromal tumour or scar histology.

CONCLUSION

Operative efficiency appears to improve as surgeons completed 16 TEM cases. We have identified important factors that result in longer operating time. The study has important implications with regard to surgical training and operative planning for new TEM programmes.

Family Adaptation to a Child's Transplant: Pretransplant Phase

The purpose of this study was to explore the relationship between family stress, family coping, social support, perception of stress, and family adaptation from the mother's perspective during the pretransplant period in the context of the Double ABC-X Model of Family Adaptation. The process of seeking a transplant for a child is very stressful, and before interventions can be developed, clinicians need to understand how aspects of family life are affected. Twenty-nine mothers whose children were being evaluated for a liver transplant constituted the sample for this exploratory study. Higher family strains, fewer coping skills, and higher perception of stress were related to more unhealthy family adaptation during the pre-transplant phase. Data point to the need for close evaluation not only for the child's needs but for the family's needs as the family begins the process of seeking a transplant for the child.

Improving skills and care standards in the support workforce for older people: a realist synthesis of workforce development interventions

OBJECTIVES

This evidence review was conducted to understand how and why workforce development interventions can improve the skills and care standards of support workers in older people's services.

DESIGN

Following recognised realist synthesis principles, the review was completed by (1) development of an initial programme theory; (2) retrieval, review and synthesis of evidence relating to interventions designed to develop the support workforce; (3) 'testing out' the synthesis findings to refine the programme theories, and establish their practical relevance/potential for implementation through stakeholder interviews; and (4) forming actionable recommendations.

PARTICIPANTS

Stakeholders who represented services, commissioners and older people were involved in workshops in an advisory capacity, and 10 participants were interviewed during the theory refinement process.

RESULTS

Eight context-mechanism-outcome (CMO) configurations were identified which cumulatively comprise a new programme theory about 'what works' to support workforce development in older people's services. The CMOs indicate that the design and delivery of workforce development includes how to make it real to the work of those delivering support to older people; the individual support worker's personal starting points and expectations of the role; how to tap into support workers' motivations; the use of incentivisation; joining things up around workforce development; getting the right mix of people engaged in the design and delivery of workforce development programmes/interventions; taking a planned approach to workforce development, and the ways in which components of interventions reinforce one another, increasing the potential for impacts to embed and spread across organisations.

CONCLUSIONS

It is important to take a tailored approach to the design and delivery of workforce development that is mindful of the needs of older people, support workers, health and social care services and the employing organisations within which workforce development operates. Workforce development interventions need to balance the technical, professional and emotional aspects of care.

TRIAL REGISTRATION NUMBER

CRD42013006283.

Assessment and Optimisation of Lung Cancer Patients for Treatment with Curative Intent

Over the past decade the field of lung cancer management has seen many developments. Coupled with an ageing population and increasing rates of comorbid illness, the work-up for treatments with curative intent has become more complex and detailed. As well as improvements in imaging and staging techniques, developments in both surgery and radiotherapy may now allow patients who would previously have been considered unfit or not appropriate for treatment with curative intent to undergo radical therapies. This overview will highlight published studies relating to investigation and staging techniques, together with assessments of fitness, with the aim of helping clinicians to determine the most appropriate treatments for each patient. We also highlight areas where further research may be required.

DNA copy number variants: A potentially useful predictor of early onset renal failure in boys with posterior urethral valves

INTRODUCTION

Posterior urethral valves (PUV) are among the most common urological causes of chronic kidney disease (CKD) in childhood. Recently, genomic imbalances have been cited as potential risk factors for altered kidney function and have been associated with CKD. The phenotypic effects of a copy number variant (CNV) in boys with PUV are unknown. Here, it was hypothesised that the progression to early renal failure in PUV patients may be influenced by genetic aberrations.

OBJECTIVE

To assess the relationship between CNVs and renal outcomes.

PATIENTS AND METHODS

Between September 2012 and July 2015, 45 children with PUV were recruited to evaluate the presence of CNVs in their DNA. The patients' medical records were retrospectively reviewed. The criteria for outcomes of renal function included: assessments of the nadir serum creatinine in the first year of life, the estimated glomerular filtration rate at 1 and 5 years, and the requirement for renal replacement.

RESULTS

Thirteen CNVs were identified in 12 boys (29% of the cohort). Microarray analysis revealed two pathogenic CNVs (well-established CNVs known to be associated with genetic disease) and 11 of unknown significance (CNVs with insufficient current available evidence for unequivocal determination of clinical significance), including genes that have been previously implicated in kidney diseases and urogenital disorders. The median follow-up was 10.2 years (range 3-17.5) in the group of patients with CNV compared with 5.8 years (range 1-16.6) in those CNV-. The nadir creatinine values were significantly higher in boys with CNVs than in those without CNVs (57.5 μmol/L (range 23-215) and 28 μmol/L (range 18-155), respectively (P = 0.05) (Figure). Boys CNV+ had a worse prognosis, with a higher incidence of Stage-V CKD compared with the control group (33% with CNVs vs. 9% in CNV-, P = 0.06) at a median age of 22 months (range 8 months-16 years). Four (33%) patients CNV+ underwent renal transplantation.

DISCUSSION

The role of CNVs in the deterioration of renal function remains unknown. It can be hypothesised that CNVs could be a contributing factor or may serve as an accelerant for the progression to renal failure.

CONCLUSION

The CNVs >100 Kb were significantly associated with early onset renal failure in children with PUV. Prenatal detection of CNV could help to identify foetuses at high risk of severe renal impairment in cases of suspected PUV, especially in cases without oligohydramnios or severe pulmonary hypoplasia. These preliminary results should be confirmed in a larger cohort of patients.

Energy recovery from human faeces via gasification: A thermodynamic equilibrium modelling approach

Non-sewered sanitary systems (NSS) are emerging as one of the solutions to poor sanitation because of the limitations of the conventional flush toilet. These new sanitary systems are expected to safely treat faecal waste and operate without external connections to a sewer, water supply or energy source. The Nano Membrane Toilet (NMT) is a unique domestic-scale sanitary solution currently being developed to treat human waste on-site. This toilet will employ a small-scale gasifier to convert human faeces into products of high energy value. This study investigated the suitability of human faeces as a feedstock for gasification. It quantified the recoverable exergy potential from human faeces and explored the optimal routes for thermal conversion, using a thermodynamic equilibrium model. Fresh human faeces were found to have approximately 70-82 wt.% moisture and 3-6 wt.% ash. Product gas resulting from a typical dry human faeces (0 wt.% moisture) had LHV and exergy values of 17.2 MJ/kg and 24 MJ/kg respectively at optimum equivalence ratio of 0.31, values that are comparable to wood biomass. For suitable conversion of moist faecal samples, near combustion operating conditions are required, if an external energy source is not supplied. This is however at 5% loss in the exergy value of the gas, provided both thermal heat and energy of the gas are recovered. This study shows that the maximum recoverable exergy potential from an average adult moist human faeces can be up to 15 MJ/kg, when the gasifier is operated at optimum equivalence ratio of 0.57, excluding heat losses, distribution or other losses that result from operational activities.

Building Genetic Competence Through Partnerships and Interactive Models

BACKGROUND

Nurses are increasingly using genetic-directed therapies in routine care, but evidence indicates that nurse educators lack knowledge about basic genetic concepts and related clinical implications. Educators are the key to preparing future nurses for effective practice in the genomic era, and creative approaches are needed for faculty development.

METHOD

Nurse educators in academic and clinical settings partnered with science educators who use sophisticated DNA, RNA, and protein models to explore ways to teach abstract genetic concepts.

RESULTS

Hands-on learning enabled the workshop participants to understand how transcription of gene mutations leads to the translation of defective proteins responsible for specific diseases. Participants found using the models helped clarified complex concepts that occur at the cellular level.

CONCLUSION

Partnerships with science educators can address gaps in nurse educators' knowledge about genetics and introduce creative teaching strategies. [J Nurs Educ. 2016;55(5):300-303.].

Clinical evaluation of the intestinal microcirculation using sidestream dark field imaging--recommendations of a round table meeting

INTRODUCTION

In clinical setting, Sidestream Dark Field (SDF) imaging has provided unprecedented insights into the gut microcirculation mainly by studying the intestinal mucosa of patients with ileostomies. Visualizing microvascular structure and function of ileal mucosa at the bedside brings unique opportunity for clinical research, particularly in critically ill patients. Several papers that were focused on intestinal microcirculation, used different methods of assessment because an accepted scoring systems does not exist so far and it is no surprise that it is rather difficult to compare the results from these studies. The present paper presents recommendations concerning specific aspects of image acquisition and proposes some parameters for the description of the intestinal microcirculation in human studies, as suggested by the participants of a round table meeting.

METHODS

The round table meeting participants reviewed all relevant literature, discussed various aspects of image acquisition by SDF technology in patients with ileostomy and parameters for the description of intestinal mucosa microcirculation. Selected key conditions for high quality and reproducible image recordings were identified. To evaluate quality of intestinal microcirculation, selected parameters and scoring system were suggested and described.

RESULTS

For image acquisition in ileostomies, five key points were proposed: optimal timing, optimal SDF device probe positioning, optimal stabilization, optimal number and length of acquired video recordings, and optimal avoidance of pressure artefacts. With regard to image analysis, simplified set of quantitative and qualitative parameters for the description of the intestinal mucosa microcirculation for the clinical studies has been proposed: vessels per villus, microvascular flow index, proportion of perfused villi, and borders of villi. The proposed parameters can be included in a semi-quantitative scoring system; however, this scoring system needs further validation. This simplified analysis does not require sophisticated software and can be performed manually on the video screen.

CONCLUSION

We propose a simple methodology for image acquisition and suggest specific microvascular parameters to analyze SDF imaging studies of the intestinal mucosa microcirculation in patients with ileostomy. Proposed scoring system needs to be validated in further clinical studies.

Observation of Gravitational Waves from a Binary Black Hole Merger

On September 14, 2015 at 09:50:45 UTC the two detectors of the Laser Interferometer Gravitational-Wave Observatory simultaneously observed a transient gravitational-wave signal. The signal sweeps upwards in frequency from 35 to 250 Hz with a peak gravitational-wave strain of 1.0×10(-21). It matches the waveform predicted by general relativity for the inspiral and merger of a pair of black holes and the ringdown of the resulting single black hole. The signal was observed with a matched-filter signal-to-noise ratio of 24 and a false alarm rate estimated to be less than 1 event per 203,000 years, equivalent to a significance greater than 5.1σ. The source lies at a luminosity distance of 410(-180)(+160)  Mpc corresponding to a redshift z=0.09(-0.04)(+0.03). In the source frame, the initial black hole masses are 36(-4)(+5)M⊙ and 29(-4)(+4)M⊙, and the final black hole mass is 62(-4)(+4)M⊙, with 3.0(-0.5)(+0.5)M⊙c(2) radiated in gravitational waves. All uncertainties define 90% credible intervals. These observations demonstrate the existence of binary stellar-mass black hole systems. This is the first direct detection of gravitational waves and the first observation of a binary black hole merger.

Sample collection and amino acids analysis of extracellular fluid of mouse brain slices with low flow push-pull perfusion

Brain tissue slices are a common neuroscience model that allows relatively sophisticated analysis of neuronal networks in a simplified preparation. Most experimental methodology utilizes electrophysiological tools to probe these model systems. The work here demonstrates the adaptation of low-flow push-pull perfusion sampling (LFPS) to a brain slice system. LFPS is used to sample from the hippocampus of mouse brain slices. Perfusate amino acid levels are quantified following sampling with capillary electrophoresis. Glutamate was measured from the CA1 region of the hippocampus in slices taken from a cystine-glutamate transporter deletion mutant, xCT(-/-), and the background strain C57BL/6J. Sampling is performed over up to 6.5 h with standard tissue slice preparation and experimentation methods. Four amino acids were quantified to demonstrate the ability to perform LFPS and show good agreement with published literature. Perfusate glutamate levels are found to be significantly lower with xCT(-/-) slices (1.9(±0.5) μM) relative to controls (4.90(±1.1) μM). But, experiments with control slices show a significant decrease in glutamate over the 6 h sampling period that are not seen with xCT(-/-) slices. Increasing the LFPS sample collection rate during the first 90 min of sampling did not show a sampling artifact in perfusate glutamate content. Sampling immediately following slicing did not show an early increasing glutamate level that would be indicative of a significant contribution from blood or tissue damage. The data presented here show a complementarity to electrophysiological studies of tissue slices. The ability to characterize extracellular fluid chemical content with LFPS in these slices provides an alternative data stream for probing neurochemical signaling networks in brain tissue slices.