The Reflective Practitioner: The challenges of supporting Public Sector Senior Leaders as they engage in reflective practice

This paper explores the challenges, issues and benefits of reflective practice faced by work-based practitioners undertaking negotiated experiential learning. The study focuses upon the case of a ground-breaking UK based Senior Leader Master’s Degree Apprenticeship (SLMDA) programme which requires learners to develop and apply reflective practice skills through comprehensive work-based learning and research activities. Degree apprenticeships represent a significant opportunity for providers and employers to become more closely aligned in the joint development and promotion of innovative learning opportunities, yet the efficacy of individually negotiated, experiential learning and reflective practice for senior leaders within a challenging healthcare environment remains relatively unexplored from a tripartite perspective. This paper investigates the role of reflective practice within a leading degree apprenticeship programme which embraces this pedagogic approach and considers the potential barriers and benefits for learners and their organisations. The paper begins by discussing the nature of reflective practice in the workplace and explores the growing importance of this activity in contemporary organisations. Theoretical and conceptual foundations relating to experiential learning and reflective practice are analysed and discussed. The SLMDA programme and NHS case organisation are described in detail. Qualitative data drawn from semi-structured interviews undertaken with learners, employers and Personal Academic Tutors (PATs) is then analysed to identify the key issues and challenges encountered. The study identifies the benefits of reflective practice, explores the challenges and issues that act as barriers to reflective practice and highlights the importance of the role of the Personal Academic Tutor (PAT) and that of employers in supporting and developing reflective practice in one of the first SLMDA programmes to launch within the UK. Although reflective practice and work-based research have attracted considerable scholarly activity, investigations have overwhelmingly been focused upon professions such as teaching and nursing and have explored challenges and issues from the perspective of the provider. This study explores reflective practice from the viewpoint of learners, employers and PATs and thereby seeks to compliment and expand current understanding by developing a more holistic approach. This work will inform future programme design, practitioner skills development and employer support procedures as learners plan and prepare to facilitate work- based research projects within their organisations

Diphthamide modification of eEF2 requires a J-domain protein and is essential for normal development

The intracellular target of diphtheria toxin is a modified histidine residue, diphthamide, in the translation elongation factor, eEF2. This enigmatic modification occurs in all eukaryotes, and is produced in yeast by the action of five gene products, DPH1 to DPH5. Sequence homologues of these genes are present in all sequenced eukaryotic genomes and in higher eukaryotes there is functional evidence for DPH1, 2, 3, and 5 acting in diphthamide biosynthesis. We have identified a mouse mutant in the remaining gene, Dph4. Cells derived from homozygous mutant embryos lack the diphthamide modification of EF2 and are resistant to killing by diphtheria toxin. Reporter-tagged DPH4 protein localizes to the cytoskeleton, in contrast to the localization of DPH1, and consistent with evidence that DPH4 is not part of a proposed complex containing DPH1, 2 and 3. Mice homozygous for the mutation are retarded in growth and development and almost always die before birth. Those that survive long enough have preaxial polydactyly, a duplication of digit 1 of the hind foot. This same defect is seen in embryos homozygous for mutation of DPH1, suggesting that lack of diphthamide on eEF2 could result in translational failure of specific proteins, rather than a generalized translation downregulation

The Dct−/− Mouse Model to Unravel Retinogenesis Misregulation in Patients with Albinism

We have recently identified encoding dopachrome tautomerase (DCT) as the eighth gene for oculocutaneous albinism (OCA). Patients with loss of function of suffer from eye hypopigmentation and retinal dystrophy. Here we investigate the eye phenotype in mice. We show that their retinal pigmented epithelium (RPE) is severely hypopigmented from early stages, contrasting with the darker melanocytic tissues. Multimodal imaging reveals specific RPE cellular defects. Melanosomes are fewer with correct subcellular localization but disrupted melanization. RPE cell size is globally increased and heterogeneous. P-cadherin labeling of newborn RPE reveals a defect in adherens junctions similar to what has been described in tyrosinase-deficient embryos. The first intermediate of melanin biosynthesis, dihydroxyphenylalanine (L-Dopa), which is thought to control retinogenesis, is detected in substantial yet significantly reduced amounts in postnatal mouse eyecups. L-Dopa synthesis in the RPE alone remains to be evaluated during the critical period of retinogenesis. The mouse should prove useful in understanding the molecular regulation of retinal development and aging of the hypopigmented eye. This may guide therapeutic strategies to prevent vision deficits in patients with albinism.Approches de génétique moléculaire et fonctionnelle pour déchiffrer les mécanismes physiopathologiques de l'albinisme oculocutané

Pro–B-Type Natriuretic Peptide1–108 Circulates in the General Community Plasma Determinants and Detection of Left Ventricular Dysfunction

ObjectivesThe purpose of this study was to investigate circulating pro–B-type natriuretic peptide (proBNP1–108) in the general community and evaluate its ability to detect left ventricular (LV) dysfunction.BackgroundThe current concept for cardiac endocrine function is that, in response to cardiac stress, the heart secretes B-type natriuretic peptide (BNP1–32) and amino-terminal pro–B-type natriuretic peptide (NT-proBNP1–76) after intracardiac cleavage of their molecular precursor, proBNP1–108. We hypothesized that proBNP1–108 circulates in normal human subjects and that it is a useful biomarker for LV dysfunction.MethodsOur population-based study included a cohort of 1,939 adults (age ≥45 years) from Olmsted County, Minnesota, with 672 participants defined as healthy. Subjects underwent in-depth clinical characterization, detailed echocardiography, and measurement of proBNP1–108. Independent factors associated with proBNP1–108 and test characteristics for the detection of LV dysfunction were determined.ResultsProBNP1–108 in normal humans was strongly influenced by sex, age, heart rate, and body mass index. The median concentration was 20 ng/l with a mean proBNP1–108 to NT-proBNP1–76 ratio of 0.366, which decreased with heart failure stage. ProBNP1–108 was a sensitive (78.8%) and specific (86.1%) biomarker for detecting LV systolic dysfunction, which was comparable to BNP1–32, but less than NT-proBNP1–76, in several subsets of the population.ConclusionsProBNP1–108 circulates in the majority of healthy humans in the general population and is a sensitive and specific biomarker for the detection of systolic dysfunction. The proBNP1–108 to NT-proBNP1–76 ratio may provide insights into altered proBNP1–108 processing during heart failure progression. Thus, this highly specific assay for proBNP1–108 provides important new insights into the biology of the BNP system

Centriolar satellites expedite mother centriole remodeling to promote ciliogenesis

Centrosomes are orbited by centriolar satellites, dynamic multiprotein assemblies nucleated by Pericentriolar material 1 (PCM1). To study the requirement for centriolar satellites, we generated mice lacking PCM1, a crucial component of satellites. Pcm1−/− mice display partially penetrant perinatal lethality with survivors exhibiting hydrocephalus, oligospermia, and cerebellar hypoplasia, and variably expressive phenotypes such as hydronephrosis. As many of these phenotypes have been observed in human ciliopathies and satellites are implicated in cilia biology, we investigated whether cilia were affected. PCM1 was dispensable for ciliogenesis in many cell types, whereas Pcm1−/− multiciliated ependymal cells and human PCM1−/− retinal pigmented epithelial 1 (RPE1) cells showed reduced ciliogenesis. PCM1−/− RPE1 cells displayed reduced docking of the mother centriole to the ciliary vesicle and removal of CP110 and CEP97 from the distal mother centriole, indicating compromised early ciliogenesis. Similarly, Pcm1−/− ependymal cells exhibited reduced removal of CP110 from basal bodies in vivo. We propose that PCM1 and centriolar satellites facilitate efficient trafficking of proteins to and from centrioles, including the departure of CP110 and CEP97 to initiate ciliogenesis, and that the threshold to trigger ciliogenesis differs between cell types

Dopachrome tautomerase variants in patients with oculocutaneous albinism

Purpose: Albinism is a clinically and genetically heterogeneous condition. Despite analysis of the 20 known genes, ~30% patients remain unsolved. We aimed to identify new genes involved in albinism. Methods: We sequenced a panel of genes with known or predicted involvement in melanogenesis in 230 unsolved albinism patients. Results: We identified variants in the Dopachrome tautomerase (DCT) gene in two patients. One was compound heterozygous for a 14-bp deletion in exon 9 and c.118T>A p.(Cys40Ser). The second was homozygous for c.183C>G p.(Cys61Trp). Both patients had mild hair and skin hypopigmentation, and classical ocular features. CRISPR-Cas9 was used in C57BL/6J mice to create mutations identical to the missense variants carried by the patients, along with one loss-of-function indel. When bred to homozygosity the three mutations revealed hypopigmentation of the coat, milder for Cys40Ser compared with Cys61Trp or the frameshift mutation. Histological analysis identified significant hypopigmentation of the retinal pigmented epithelium (RPE) indicating that defective RPE melanogenesis could be associated with eye and vision defects. DCT loss of function in zebrafish embryos elicited hypopigmentation both in melanophores and RPE cells. Conclusion: DCT is the gene for a new type of oculocutaneous albinism that we propose to name OCA8

Ciliary tip actin dynamics regulate photoreceptor outer segment integrity

As signalling organelles, cilia regulate their G protein-coupled receptor content by ectocytosis, a process requiring localised actin dynamics to alter membrane shape. Photoreceptor outer segments comprise an expanse of folded membranes (discs) at the tip of highly-specialised connecting cilia, into which photosensitive GPCRs are concentrated. Discs are shed and remade daily. Defects in this process, due to mutations, cause retinitis pigmentosa (RP). Whilst fundamental for vision, the mechanism of photoreceptor disc generation is poorly understood. Here, we show membrane deformation required for disc genesis is driven by dynamic actin changes in a process akin to ectocytosis. We show RPGR, a leading RP gene, regulates actin-binding protein activity central to this process. Actin dynamics, required for disc formation, are perturbed in Rpgr mouse models, leading to aborted membrane shedding as ectosome-like vesicles, photoreceptor death and visual loss. Actin manipulation partially rescues this, suggesting the pathway could be targeted therapeutically. These findings help define how actin-mediated dynamics control outer segment turnover

Monoallelic variants resulting in substitutions of MAB21L1 Arg51 Cause Aniridia and microphthalmia

Classical aniridia is a congenital and progressive panocular disorder almost exclusively caused by heterozygous loss-of-function variants at the PAX6 locus. We report nine individuals from five families with severe aniridia and/or microphthalmia (with no detectable PAX6 mutation) with ultrarare monoallelic missense variants altering the Arg51 codon of MAB21L1. These mutations occurred de novo in 3/5 families, with the remaining families being compatible with autosomal dominant inheritance. Mice engineered to carry the p.Arg51Leu change showed a highly-penetrant optic disc anomaly in heterozygous animals with severe microphthalmia in homozygotes. Substitutions of the same codon (Arg51) in MAB21L2, a close homolog of MAB21L1, cause severe ocular and skeletal malformations in humans and mice. The predicted nucleotidyltransferase function of MAB21L1 could not be demonstrated using purified protein with a variety of nucleotide substrates and oligonucleotide activators. Induced expression of GFP-tagged wildtype and mutant MAB21L1 in human cells caused only modest transcriptional changes. Mass spectrometry of immunoprecipitated protein revealed that both mutant and wildtype MAB21L1 associate with transcription factors that are known regulators of PAX6 (MEIS1, MEIS2 and PBX1) and with poly(A) RNA binding proteins. Arg51 substitutions reduce the association of wild-type MAB21L1 with TBL1XR1, a component of the NCoR complex. We found limited evidence for mutation-specific interactions with MSI2/Musashi-2, an RNA-binding proteins with effects on many different developmental pathways. Given that biallelic loss-of-function variants in MAB21L1 result in a milder eye phenotype we suggest that Arg51-altering monoallelic variants most plausibly perturb eye development via a gain-of-function mechanism