Axonal growth arrests after an increased accumulation of Schwann cells expressing senescence markers and stromal cells in acellular nerve allografts

Acellular nerve allografts (ANAs) and other nerve constructs do not reliably facilitate axonal regeneration across long defects (>3 cm). Causes for this deficiency are poorly understood. In this study, we determined what cells are present within ANAs before axonal growth arrest in nerve constructs and if these cells express markers of cellular stress and senescence. Using the Thy1-GFP rat and serial imaging, we identified the time and location of axonal growth arrest in long (6 cm) ANAs. Axonal growth halted within long ANAs by 4 weeks, while axons successfully regenerated across short (3 cm) ANAs. Cellular populations and markers of senescence were determined using immunohistochemistry, histology, and senescence-associated β-galactosidase staining. Both short and long ANAs were robustly repopulated with Schwann cells (SCs) and stromal cells by 2 weeks. Schwann cells (S100β(+)) represented the majority of cells repopulating both ANAs. Overall, both ANAs demonstrated similar cellular populations with the exception of increased stromal cells (fibronectin(+)/S100β(−)/CD68(−) cells) in long ANAs. Characterization of ANAs for markers of cellular senescence revealed that long ANAs accumulated much greater levels of senescence markers and a greater percentage of Schwann cells expressing the senescence marker p16 compared to short ANAs. To establish the impact of the long ANA environment on axonal regeneration, short ANAs (2 cm) that would normally support axonal regeneration were generated from long ANAs near the time of axonal growth arrest (“stressed” ANAs). These stressed ANAs contained mainly S100β(+)/p16(+) cells and markedly reduced axonal regeneration. In additional experiments, removal of the distal portion (4 cm) of long ANAs near the time of axonal growth arrest and replacement with long isografts (4 cm) rescued axonal regeneration across the defect. Neuronal culture derived from nerve following axonal growth arrest in long ANAs revealed no deficits in axonal extension. Overall, this evidence demonstrates that long ANAs are repopulated with increased p16(+) Schwann cells and stromal cells compared to short ANAs, suggesting a role for these cells in poor axonal regeneration across nerve constructs

European Nature and Health Network Initiatives

Attention to the importance of nature and human health linkages has increased in the past years, both in science and in policy. While knowledge about and recognition of the importance of nature and human health linkages are increasing rapidly, challenges still remain. Among them are building bridges between relevant but often still somewhat disconnected sectors and topics. There is a need to bring together researchers in the fields of health sciences, ecology, social sciences, sustainability sciences and other interdisciplinary sciences, as well as for cooperation between governments, companies and citizens. In this chapter, we introduce European networking initiatives aimed at building such bridges

The Catalytic Mechanism of Electron-Bifurcating Electron Transfer Flavoproteins (ETFs) Involves an Intermediary Complex with NAD\u3csup\u3e+\u3c/sup\u3e

Electron bifurcation plays a key role in anaerobic energy metabolism, but it is a relatively new discovery, and only limited mechanistic information is available on the diverse enzymes that employ it. Herein, we focused on the bifurcating electron transfer flavoprotein (ETF) from the hyperthermophilic archaeon Pyrobaculum aerophilum. The EtfABCX enzyme complex couples NADH oxidation to the endergonic reduction of ferredoxin and exergonic reduction of menaquinone. We developed a model for the enzyme structure by using nondenaturing MS, cross-linking, and homology modeling in which EtfA, -B, and -C each contained FAD, whereas EtfX contained two [4Fe-4S] clusters. On the basis of analyses using transient absorption, EPR, and optical titrations with NADH or inorganic reductants with and without NAD+, we propose a catalytic cycle involving formation of an intermediary NAD+-bound complex. A charge transfer signal revealed an intriguing interplay of flavin semiquinones and a protein conformational change that gated electron transfer between the low- and high-potential pathways. We found that despite a common bifurcating flavin site, the proposed EtfABCX catalytic cycle is distinct from that of the genetically unrelated bifurcating NADH-dependent ferredoxin NADP+ oxidoreductase (NfnI). The two enzymes particularly differed in the role of NAD+, the resting and bifurcating-ready states of the enzymes, how electron flow is gated, and the two two-electron cycles constituting the overall four-electron reaction. We conclude that P. aerophilum EtfABCX provides a model catalytic mechanism that builds on and extends previous studies of related bifurcating ETFs and can be applied to the large bifurcating ETF family

Psychometric properties and use of the DEMQOL suite of instruments in research: a systematic review protocol

Dementia is a public health issue and a major risk factor for poor quality of life among older adults. In the absence of a cure, enhancing health-related quality of life (HRQoL) of people with dementia is the primary goal of care. Robust measurement of HRQoL is a prerequisite to effective improvement. The DEMQOL suite of instruments is considered among the best available to measure HRQoL in people with dementia; however, no review has systematically and comprehensively examined the use of the DEMQOL in research and summarised evidence to determine its feasibility, acceptability and appropriateness for use in research and practice. Methods and analysis: We will systematically search 12 electronic databases and reference lists of all included studies. We will include systematically conducted reviews, as well as, quantitative and qualitative research studies that report on the development, validation or use in research studies of any of the DEMQOL instruments. Two reviewers will independently screen all studies for eligibility, and assess the quality of each included study using one of four validated checklists appropriate for different study designs. Discrepancies at all stages of the review will be resolved by consensus. We will use descriptive statistics (frequencies, proportions, ranges), content analysis of narrative data and vote counting (for the measures of association) to summarise the data elements. Using narrative synthesis, we will summarise what is known about the development, validation, feasibility, acceptability, appropriateness and use of the DEMQOL. Our review methods will follow the reporting and conduct guidelines of the Cochrane Handbook for Systematic Reviews of Interventions and the Preferred Reporting Items for Systematic Reviews and Meta-Analysis. Ethics and dissemination: Ethical approval is not required as this project does not involve primary data collection. We will disseminate our findings through peer-reviewed publications and conference presentations. PROSPERO registration number CRD42020157851

The kinetics and mechanism of the organo-iridium catalysed racemisation of amines

The dimeric iodo-iridium complex [IrCp*I2 ]2 (Cp*=pentamethylcyclopentadiene) is an efficient catalyst for the racemisation of secondary and tertiary amines at ambient and higher temperatures with a low catalyst loading. The racemisation occurs with pseudo-first-order kinetics and the orresponding four rate constants were obtained by monitoring the time dependence of the concentrations of the (R) and (S) enantiomers starting with either pure (R) or (S) and show a first-order dependence on catalyst concentration. Low temperature 1H NMR data is consistent with the formation of a 1:1 complex with the amine coordinated to the iridium and with both iodide anions still bound to the metal-ion, but at the higher temperatures used for kinetic studies binding is weak and so no saturation zero-order kinetics are observed. A cross-over experiment with isotopically labelled amines demonstrates the intermediate formation of an imine which can dissociate from the iridium complex. Replacing the iodides in the catalyst by other ligands or having an amide substituent in Cp* results in a much less effective catalysts for the racemisation of amines. The rate constants for a deuterated amine yield a significant primary kinetic isotope effect kH/kD = 3.24 ndicating that hydride transfer is involved in the rate-limiting step

A systematic review of the association between nursing staff and nursing-sensitive outcomes in long-term institutional care

Aims To examine the association between type of nursing staff and nursing-sensitive outcomes in long-term institutional care. Design This systematic review included studies published in English, German, and Dutch between January 1997 and January 2020. Data sources The databases Medline (PubMed), CINAHL, PsycINFO, Embase, and the Cochrane Library were searched. Original quantitative studies were included. Review methods The Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) guidelines were followed. The Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) checklist was used to critically appraise the reporting of the studies. Results Fifteen articles were included. Of 33 quality of care outcomes, 21 were identified as nursing-sensitive outcomes of which 13 showed a significant association with nursing staff, specifically: Activities of daily living, aggressive behavior, bladder/bowel incontinence, contractures, expressive language skills, falls, infection (including vaccination), range of motion, pain, pressure ulcers, and weight loss. However, studies reported inconsistent results regarding the association among RNs, LPNs, CNAs, and HCAs and these nursing-sensitive outcomes, evidence shows that more RNs have a positive impact on nursing-sensitive outcomes. As to the evidence regarding the other type of nursing staff, especially HCA, findings regularly showed a negative association. Conclusion Future research should be expanded with structure and process variables of which the mediating and moderating effect on nursing-sensitive outcomes is known. These may explain variances in quality of care and guide quality improvement initiatives. Researchers should consider fully applying Donabedian's structure-process-outcomes framework as it is a coherent entirety for quality assessment. Impact This review provides an overview of quality of care outcomes that are responsive to nursing interventions in long-term institutional care. As the effects can be monitored and documented, quality assessment should focus on these nursing-sensitive outcomes. The inconclusive results make it difficult to provide recommendations on who should best perform which care

Dynamic assessment of word learning skills of preschool children with primary language impairment

Dynamic assessment has been shown to have considerable theoretical and clinical significance in the assessment of socially disadvantaged and culturally and linguistically diverse children. In this study it is used to enhance assessment of pre-school children with primary language impairment. The purpose of the study was to determine whether a dynamic assessment (DA) has the potential to enhance the predictive capacity of a static measure of receptive vocabulary in pre-school children. Forty pre-school children were assessed using the static British Picture Vocabulary Scale (BPVS), a DA of word learning potential and an assessment of non-verbal cognitive ability. Thirty-seven children were followed up 6 months later and re-assessed using the BPVS. Although the predictive capacity of the static measure was found to be substantial, the DA increased this significantly especially for children with static scores below the 25th centile. The DA of children's word learning has the potential to add value to the static assessment of the child with low language skills, to predict subsequent receptive vocabulary skills and to increase the chance of correctly identifying children in need of ongoing support

Factors Associated With the Quality of Life of Nursing Home Residents During the COVID-19 Pandemic: A Cross-Sectional Study

Objectives Quality of life (QoL) of nursing home (NH) residents is critical, yet understudied, particularly during the COVID-19 pandemic. Our objective was to examine whether COVID-19 outbreaks, lack of access to geriatric professionals, and care aide burnout were associated with NH residents' QoL. Design Cross-sectional study (July to December 2021). Setting and Participants We purposefully selected 9 NHs in Alberta, Canada, based on their COVID-19 exposure (no or minor/short outbreaks vs repeated or extensive outbreaks). We included data for 689 residents from 18 care units. Methods We used the DEMQOL-CH to assess resident QoL through video-based care aide interviews. Independent variables included a COVID-19 outbreak in the NH in the past 2 weeks (health authority records), care unit-levels of care aide burnout (9-item short-form Maslach Burnout Inventory), and resident access to geriatric professionals (validated facility survey). We ran mixed-effects regression models, adjusted for facility and care unit (validated surveys), and resident covariates (Resident Assessment Instrument–Minimum Data Set 2.0). Results Recent COVID-19 outbreaks (β = 0.189; 95% CI: 0.058–0.320), higher proportions of emotionally exhausted care aides on a care unit (β = 0.681; 95% CI: 0.246–1.115), and lack of access to geriatric professionals (β = 0.216; 95% CI: 0.003–0.428) were significantly associated with poorer resident QoL. Conclusions and Implications Policies aimed at reducing infection outbreaks, better supporting staff, and increasing access to specialist providers may help to mitigate how COVID-19 has negatively affected NH resident QoL