Modelling Inherited Prion Diseases In Mice

Prion diseases are fatal neurodegenerative diseases of mammals, caused by a misfolded infectious protein. There are 3 aetiological forms namely sporadic, acquired or inherited. The genetic component makes it possible for transgenic technology to be applied to the modelling of prion diseases. In 2013 Mead et al. reported a novel prion disease linked to a stop codon mutation at residue 163 (Y163X) in the human prion protein gene (PRNP). This mutation results in the production of a truncated prion protein (PrP) lacking both glycosylation sites and GPI anchor, and it is associated with an atypical prion disease phenotype including diarrhoea, autonomic neuropathy and the accumulation of PrP amyloid in peripheral organs and blood vessels. Typically, prion diseases predominantly affect the nervous system so the uniqueness of the Y163X disease phenotype makes it a good candidate for the study of prion therapeutics. The aim of this project was therefore to develop mouse models expressing human PrP Y163X that recapitulate human disease and then to study ageing cohorts of homozygous and heterozygous mice for spontaneous amyloid deposition. Two different approaches were pursued as follows: (1) Conventional transgenic approach (2) Gene targeted approach (CRISPR- Cas9 and knock-in technology). Six transgenic lines expressing HuPrP 163X under the control of the ubiquitous CAG promoter were generated alongside transgenic wild-type controls expressing wild-type human PrP. Y163X knock-in mice and control knock-in mice expressing wild-type human PrP generated from blastocyst injection of embryonic stem cells were made commercially. These lines were characterised for expression of the truncated 163X human prion protein using techniques such as western blotting, ELISA, fluorescent immunohistochemistry and RT-PCR. Aging cohorts from homozygous lines were set up in long term observation experiments. A panel of CNS and peripheral tissues has been isolated at defined time points for immunohistochemical analysis to determine if the expression of HuPrP Y163X in transgenic and knock-in mice is sufficient to cause spontaneous PrP amyloid deposition

Healthcare Professionals’ Experiences of the Barriers and Facilitators to Pediatric Pain Management in the Community at End-of-Life: A Qualitative Interview Study

Contexts: Inadequate pain management in community pediatric palliative care is common. Evidence to inform improved pain management in this population is limited. Objectives: To explore the barriers and facilitators to pediatric community-based pain management for infants, children and young people at end-of-life as perceived by healthcare professionals. Methods: A qualitative interview study was conducted. Semi-structured interviews were undertaken with 29 healthcare professionals; 12 nurses, five GPs, five consultants and registrar doctors, two pharmacists and five support therapists working in primary, secondary or tertiary care in the United Kingdom and involved in community end-of life care of 0 to 18-year-olds. Results: The data corpus was analyzed using an inductive thematic analysis and seven themes emerged: parents’ abilities, beliefs and wellbeing; working relationships between families and healthcare professionals, and between healthcare teams; healthcare professionals’ knowledge, education and experience; health services delivery; nature of pain treatment; and pediatric-specific factors. Across themes, the concepts of partnership working between families and healthcare professionals, and within healthcare teams, and sharing expertise were prevalent. Conclusion: Partnership working and trust between healthcare professionals and parents, and within healthcare teams, is needed for effective at-home pediatric palliative pain management. Community healthcare professionals require more education from experienced multidisciplinary teams to effectively manage pediatric pain at end-of-life and prevent emergency hospice or hospital admissions, particularly during the COVID-19 pandemic.</p

Weaning from mechanical ventilation in intensive care units across 50 countries (WEAN SAFE): a multicentre, prospective, observational cohort study

Background Current management practices and outcomes in weaning from invasive mechanical ventilation are poorly understood. We aimed to describe the epidemiology, management, timings, risk for failure, and outcomes of weaning in patients requiring at least 2 days of invasive mechanical ventilation. Methods WEAN SAFE was an international, multicentre, prospective, observational cohort study done in 481 intensive care units in 50 countries. Eligible participants were older than 16 years, admitted to a participating intensive care unit, and receiving mechanical ventilation for 2 calendar days or longer. We defined weaning initiation as the first attempt to separate a patient from the ventilator, successful weaning as no reintubation or death within 7 days of extubation, and weaning eligibility criteria based on positive end-expiratory pressure, fractional concentration of oxygen in inspired air, and vasopressors. The primary outcome was the proportion of patients successfully weaned at 90 days. Key secondary outcomes included weaning duration, timing of weaning events, factors associated with weaning delay and weaning failure, and hospital outcomes. This study is registered with ClinicalTrials.gov, NCT03255109. Findings Between Oct 4, 2017, and June 25, 2018, 10 232 patients were screened for eligibility, of whom 5869 were enrolled. 4523 (77·1%) patients underwent at least one separation attempt and 3817 (65·0%) patients were successfully weaned from ventilation at day 90. 237 (4·0%) patients were transferred before any separation attempt, 153 (2·6%) were transferred after at least one separation attempt and not successfully weaned, and 1662 (28·3%) died while invasively ventilated. The median time from fulfilling weaning eligibility criteria to first separation attempt was 1 day (IQR 0–4), and 1013 (22·4%) patients had a delay in initiating first separation of 5 or more days. Of the 4523 (77·1%) patients with separation attempts, 2927 (64·7%) had a short wean (≤1 day), 457 (10·1%) had intermediate weaning (2–6 days), 433 (9·6%) required prolonged weaning (≥7 days), and 706 (15·6%) had weaning failure. Higher sedation scores were independently associated with delayed initiation of weaning. Delayed initiation of weaning and higher sedation scores were independently associated with weaning failure. 1742 (31·8%) of 5479 patients died in the intensive care unit and 2095 (38·3%) of 5465 patients died in hospital. Interpretation In critically ill patients receiving at least 2 days of invasive mechanical ventilation, only 65% were weaned at 90 days. A better understanding of factors that delay the weaning process, such as delays in weaning initiation or excessive sedation levels, might improve weaning success rates

Weaning from mechanical ventilation in intensive care units across 50 countries (WEAN SAFE): a multicentre, prospective, observational cohort study

Background: Current management practices and outcomes in weaning from invasive mechanical ventilation are poorly understood. We aimed to describe the epidemiology, management, timings, risk for failure, and outcomes of weaning in patients requiring at least 2 days of invasive mechanical ventilation. Methods: WEAN SAFE was an international, multicentre, prospective, observational cohort study done in 481 intensive care units in 50 countries. Eligible participants were older than 16 years, admitted to a participating intensive care unit, and receiving mechanical ventilation for 2 calendar days or longer. We defined weaning initiation as the first attempt to separate a patient from the ventilator, successful weaning as no reintubation or death within 7 days of extubation, and weaning eligibility criteria based on positive end-expiratory pressure, fractional concentration of oxygen in inspired air, and vasopressors. The primary outcome was the proportion of patients successfully weaned at 90 days. Key secondary outcomes included weaning duration, timing of weaning events, factors associated with weaning delay and weaning failure, and hospital outcomes. This study is registered with ClinicalTrials.gov, NCT03255109. Findings: Between Oct 4, 2017, and June 25, 2018, 10 232 patients were screened for eligibility, of whom 5869 were enrolled. 4523 (77·1%) patients underwent at least one separation attempt and 3817 (65·0%) patients were successfully weaned from ventilation at day 90. 237 (4·0%) patients were transferred before any separation attempt, 153 (2·6%) were transferred after at least one separation attempt and not successfully weaned, and 1662 (28·3%) died while invasively ventilated. The median time from fulfilling weaning eligibility criteria to first separation attempt was 1 day (IQR 0-4), and 1013 (22·4%) patients had a delay in initiating first separation of 5 or more days. Of the 4523 (77·1%) patients with separation attempts, 2927 (64·7%) had a short wean (≤1 day), 457 (10·1%) had intermediate weaning (2-6 days), 433 (9·6%) required prolonged weaning (≥7 days), and 706 (15·6%) had weaning failure. Higher sedation scores were independently associated with delayed initiation of weaning. Delayed initiation of weaning and higher sedation scores were independently associated with weaning failure. 1742 (31·8%) of 5479 patients died in the intensive care unit and 2095 (38·3%) of 5465 patients died in hospital. Interpretation: In critically ill patients receiving at least 2 days of invasive mechanical ventilation, only 65% were weaned at 90 days. A better understanding of factors that delay the weaning process, such as delays in weaning initiation or excessive sedation levels, might improve weaning success rates. Funding: European Society of Intensive Care Medicine, European Respiratory Society