AMPK-α1 or AMPK-α2 Deletion in Smooth Muscles Does Not Affect the Hypoxic Ventilatory Response or Systemic Arterial Blood Pressure Regulation During Hypoxia

The hypoxic ventilatory response (HVR) is markedly attenuated by AMPK-α1 deletion conditional on the expression of Cre-recombinase in tyrosine hydroxylase (TH) expressing cells, precipitating marked increases in apnea frequency and duration. It was concluded that ventilatory dysfunction caused by AMPK deficiency was driven by neurogenic mechanisms. However, TH is transiently expressed in other cell types during development, and it is evident that central respiratory depression can also be triggered by myogenic mechanisms that impact blood supply to the brain. We therefore assessed the effect on the HVR and systemic arterial blood pressure of AMPK deletion in vascular smooth muscles. There was no difference in minute ventilation during normoxia. However, increases in minute ventilation during severe hypoxia (8% O2) were, if affected at all, augmented by AMPK-α1 and AMPK-α2 deletion in smooth muscles; despite the fact that hypoxia (8% O2) evoked falls in arterial SpO2 comparable with controls. Surprisingly, these mice exhibited no difference in systolic, diastolic or mean arterial blood pressure during normoxia or hypoxia. We conclude that neither AMPK-α1 nor AMPK-α2 are required in smooth muscle for the regulation of systemic arterial blood pressure during hypoxia, and that AMPK-α1 deficiency does not impact the HVR by myogenic mechanisms

Reflections on conducting educational research projects in Papua New Guinea

This article discusses how work on an AusAID-funded impact study of major elementary school reforms influenced the research design of a subsequent Australian Development Research Award project investigating the development of sustainable professional learning communities for primary school teachers in remote places of PNG. The authors reflect on how their different backgrounds, roles, experiences and expertise influenced the design and conduct of the projects and, in particular, how the experiences of the action research and survey methods used on the first project shaped the design of the second. The participating elementary school teachers were encouraged, through action research approaches, to develop self reflexive attitudes to their professional work, and to engage in critical reflection of their roles and practices. Accordingly, this article adopts a self-reflexive position towards the authors&rsquo; work as academics and researchers as they endeavoured to produce methodologies that are academically rigorous, contextually suitable, and epistemologically appropriate for PNG.<br /

The LKB1-AMPK-α1 signaling pathway triggers hypoxic pulmonary vasoconstriction downstream of mitochondria

International audienceHypoxic pulmonary vasoconstriction (HPV), which aids ventilation-perfusion matching in the lungs, is triggered by mechanisms intrinsic to pulmonary arterial smooth muscles. The unique sensitivity of these muscles to hypoxia is conferred by mitochondrial cytochrome c oxidase subunit 4 isoform 2, the inhibition of which has been proposed to trigger HPV through increased generation of mitochondrial reactive oxygen species. Contrary to this model, we have shown that the LKB1-AMPK-α1 signaling pathway is critical to HPV. Spectral Doppler ultrasound revealed that deletion of the AMPK-α1 catalytic subunit blocked HPV in mice during mild (8% O2) and severe (5% O2) hypoxia, whereas AMPK-α2 deletion attenuated HPV only during severe hypoxia. By contrast, neither of these genetic manipulations affected serotonin-induced reductions in pulmonary vascular flow. HPV was also attenuated by reduced expression of LKB1, a kinase that activates AMPK during energy stress, but not after deletion of CaMKK2, a kinase that activates AMPK in response to increases in cytoplasmic Ca2+ Fluorescence imaging of acutely isolated pulmonary arterial myocytes revealed that AMPK-α1 or AMPK-α2 deletion did not affect mitochondrial membrane potential during normoxia or hypoxia. However, deletion of AMPK-α1, but not of AMPK-α2, blocked hypoxia from inhibiting KV1.5, the classical "oxygen-sensing" K+ channel in pulmonary arterial myocytes. We conclude that LKB1-AMPK-α1 signaling pathways downstream of mitochondria are critical for the induction of HPV, in a manner also supported by AMPK-α2 during severe hypoxia

Disrupted murine gut-to-human liver signaling alters bile acid homeostasis in humanized mouse liver models

The humanized liver mouse model is being exploited increasingly for human drug metabolism studies. However, its model stability, intercommunication between human hepatocytes and mouse nonparenchymal cells in liver and murine intestine, and changes in extrahepatic transporter and enzyme expressions have not been investigated. We examined these issues in FRGN [fumarylacetoacetate hydrolase (Fah2/2), recombination activating gene 2 (Rag22/2), and interleukin 2 receptor subunit gamma (IL-2rg 2/2) triple knockout] on nonobese diabetic (NOD) background] and chimeric mice: mFRGN and hFRGN (repopulated withmouse or human hepatocytes, respectively). hFRGN mice showed markedly higher levels of liver cholesterol, biliary bilirubin, and bile acids (liver, bile, and plasma; mainly human forms, but also murine bile acids) but lower transforming growth factor beta receptor 2 (TGFBR2) mRNA expression levels (10%) in human hepatocytes and other proliferative markers in mouse nonparenchymal cells (Tgf-1) and cholangiocytes [plasma membrane-bound, G protein-coupled receptor for bile acids (Tgr5)], suggestive of irregular regeneration processes in hFRGN livers. Changes in gene expression in murine intestine, kidney, and brain of hFRGN mice, in particular, induction of intestinal farnesoid X receptor (Fxr) genes: fibroblast growth factor 15 (Fgf15), mouse ileal bile acid binding protein (Ibabp), small heterodimer partner (Shp), and the organic solute transporter alpha (Osta), were observed. Proteomics revealed persistence of remnant murine proteins (cyotchrome P450 7α-hydroxylase (Cyp7a1) and other enzymes and transporters) in hFRGN livers and suggest the likelihood ofmouse activity.When comparedwith normal human liver tissue, hFRGN livers showed lower SHP mRNA and higher CYP7A1 (300%) protein expression, consequences of tb- and ta-muricholic acid-mediated inhibition of the FXR-SHP cascade and miscommunication between intestinal Fgf15 and human liver fibroblast growth factor receptor 4 (FGFR4), as confirmed by the unchanged hepatic pERK/total ERK ratio. Dysregulation of hepatocyte proliferation and bile acid homeostasis in hFRGN livers led to hepatotoxicity, gallbladder distension, liver deformity, and other extrahepatic changes, making questionable the use of the preparation for drug metabolism studies

First step to facilitate long term and multi centre studies of shear wave elastography in solid breast lesions using a computer assisted algorithm

Purpose: Shear wave elastography (SWE) visualises the elasticity of tissue. As malignant tissue is generally stiffer than benign tissue, SWE is helpful to diagnose solid breast lesions. Until now, quantitative measurements of elasticity parameters have been possible only, while the images were still saved on the ultrasound imaging device. This work aims to overcome this issue and introduces an algorithm allowing fast offline evaluation of SWE images. Methods: The algorithm was applied to a commercial phantom comprising three lesions of various elasticities and 207 in vivo solid breast lesions. All images were saved in DICOM, JPG and QDE (quantitative data export; for research only) format and evaluated according to our clinical routine using a computer-aided diagnosis algorithm. The results were compared to the manual evaluation (experienced radiologist and trained engineer) regarding their numerical discrepancies and their diagnostic performance using ROC and ICC analysis. Results: ICCs of the elasticity parameters in all formats were nearly perfect (0.861–0.990). AUC for all formats was nearly identical for ${E}_{\mathrm{max}}$ and ${E}_{\mathrm{mean}}$ (0.863–0.888). The diagnostic performance of SD using DICOM or JPG estimations was lower than the manual or QDE estimation (AUC 0.673 vs. 0.844). Conclusions: The algorithm introduced in this study is suitable for the estimation of the elasticity parameters offline from the ultrasound system to include images taken at different times and sites. This facilitates the performance of long-term and multi-centre studies

TIGA-CUB – manualised psychoanalytic child psychotherapy versus treatment as usual for children aged 5–11 years with treatment-resistant conduct disorders and their primary carers: study protocol for a randomised controlled feasibility trial

Background: The National Institute for Health and Care Excellence (NICE) recommends evidence-based parenting programmes as a first-line intervention for conduct disorders (CD) in children aged 5–11 years. As these are not effective in 25–33% of cases, NICE has requested research into second-line interventions. Child and Adolescent Psychotherapists (CAPTs) address highly complex problems where first-line treatments have failed and there have been small-scale studies of Psychoanalytic Child Psychotherapy (PCP) for CD. A feasibility trial is needed to determine whether a confirmatory trial of manualised PCP (mPCP) versus Treatment as Usual (TaU) for CD is practicable or needs refinement. The aim of this paper is to publish the abridged protocol of this feasibility trial. Methods and design: TIGA-CUB (Trial on improving Inter-Generational Attachment for Children Undergoing Behaviour problems) is a two-arm, pragmatic, parallel-group, multicentre, individually randomised (1:1) controlled feasibility trial (target n = 60) with blinded outcome assessment (at 4 and 8 months), which aims to develop an optimum practicable protocol for a confirmatory, pragmatic, randomised controlled trial (RCT) (primary outcome: child’s behaviour; secondary outcomes: parental reflective functioning and mental health, child and parent quality of life), comparing mPCP and TaU as second-line treatments for children aged 5–11 years with treatment-resistant CD and inter-generational attachment difficulties, and for their primary carers. Child-primary carer dyads will be recruited following a referral to, or re-referral within, National Health Service (NHS) Child and Adolescent Mental Health Services (CAMHS) after an unsuccessful first-line parenting intervention. PCP will be delivered by qualified CAPTs working in routine NHS clinical practice, using a trial-specific PCP manual (a brief version of established PCP clinical practice). Outcomes are: (1) feasibility of recruitment methods, (2) uptake and follow-up rates, (3) therapeutic delivery, treatment retention and attendance, intervention adherence rates, (4) follow-up data collection, and (5) statistical, health economics, process evaluation, and qualitative outcomes. Discussion: TIGA-CUB will provide important information on the feasibility and potential challenges of undertaking a confirmatory RCT to evaluate the effectiveness and cost-effectiveness of mPCP. Trial registration: Current Controlled Trials, ID: ISRCTN86725795. Registered on 31 May 2016