The association of modifiable and socio-demographic factors with first transitions from smoking to exclusive e-cigarette use, dual use or no nicotine use: Findings from the Avon Longitudinal Study of Parents and Children United Kingdom birth cohort.

Background And Aims: E-cigarettes can aid smoking cessation and reduce carcinogen exposure. Understanding differences in characteristics between young adults who quit smoking, with or without e-cigarettes, or dual use can help tailor interventions. The aim of this study was to describe first transitions from smoking and explore substance use, sociodemographic, and health characteristic associations with the probability of each possible first transition from smoking.

Multiple imputation using auxiliary imputation variables that only predict missingness can increase bias due to data missing not at random.

Background: Epidemiological and clinical studies often have missing data, frequently analysed using multiple imputation (MI). In general, MI estimates will be biased if data are missing not at random (MNAR). Bias due to data MNAR can be reduced by including other variables ("auxiliary variables") in imputation models, in addition to those required for the substantive analysis.

Analyses using multiple imputation need to consider missing data in auxiliary variables.

Auxiliary variables are used in multiple imputation (MI) to reduce bias and increase efficiency. These variables may often themselves be incomplete. We explored how missing data in auxiliary variables influenced estimates obtained from MI.

Multiple imputation strategies for missing event times in a multi-state model analysis.

In clinical studies, multi-state model (MSM) analysis is often used to describe the sequence of events that patients experience, enabling better understanding of disease progression. A complicating factor in many MSM studies is that the exact event times may not be known. Motivated by a real dataset of patients who received stem cell transplants, we considered the setting in which some event times were exactly observed and some were missing.

Multiple imputation of missing data under missing at random: including a collider as an auxiliary variable in the imputation model can induce bias.

Epidemiological studies often have missing data, which are commonly handled by multiple imputation (MI). In MI, in addition to those required for the substantive analysis, imputation models often include other variables ("auxiliary variables"). Auxiliary variables that predict the partially observed variables can reduce the standard error (SE) of the MI estimator and, if they also predict the probability that data are missing, reduce bias due to data being missing not at random.

Multiple imputation of missing data under missing at random: compatible imputation models are not sufficient to avoid bias if they are mis-specified.

Objectives: Epidemiological studies often have missing data, which are commonly handled by multiple imputation (MI). Standard (default) MI procedures use simple linear covariate functions in the imputation model. We examine the bias that may be caused by acceptance of this default option and evaluate methods to identify problematic imputation models, providing practical guidance for researchers.

Endothelial failure and rejection in recipients of corneas from the same donor.

Objective: To determine whether patients who receive corneas from the same donor have similar risks of endothelial failure and rejection.

Methods And Analysis: Patients with Fuchs endothelial dystrophy (FED) and pseudophakic bullous keratopathy (PBK) who received their first corneal transplant between 1999 and 2016 were analysed. Patients receiving corneas from donors who donated both corneas for the same indication were defined as 'paired'.

Graphical comparison of surgeon outcomes for the audit of a national corneal transplant registry (OTAG study 32).

Purpose: To compare Kaplan-Meier survival curves and funnel plots for the audit of surgeon-specific corneal transplantation outcomes.

Methods: We obtained data on all patients with Fuchs endothelial dystrophy (FED) receiving a first corneal transplant in one eye between January 2012 and December 2017. We produced 2-year Kaplan-Meier graft survival curves to compare a simulated individual surgeon's graft survival rate to national pooled data.

Long-Term Graft Survival and Decline in Endothelial Cell Density Following Penetrating Keratoplasty with Organ-Cultured Corneas.

Introduction: Endothelial cell density (ECD) changes long after penetrating keratoplasty (PKP) of organ-cultured corneas have been little studied. We aim to calculate the point when ECD decline stabilises following PKP with organ culture stored corneas.

Methods: This is an observational study of first-ever PKPs and first-ever re-grafts, performed over 17 years under a single surgeon.

Multiple imputation strategies for a bounded outcome variable in a competing risks analysis.

In patient follow-up studies, events of interest may take place between periodic clinical assessments and so the exact time of onset is not observed. Such events are known as "bounded" or "interval-censored." Methods for handling such events can be categorized as either (i) applying multiple imputation (MI) strategies or (ii) taking a full likelihood-based (LB) approach.

The Migratory Properties and Numbers of T Regulatory Cell Subsets in Circulation Are Differentially Influenced by Season and Are Associated With Vitamin D Status.

The control of peripheral immune responses by FOXP3 T regulatory (Treg) cells is essential for immune tolerance. However, at any given time, Treg frequencies in whole blood can vary more than fivefold between individuals. An understanding of factors that influence Treg numbers and migration within and between individuals would be a powerful tool for cellular therapies that utilize the immunomodulatory properties of Tregs to control pathology associated with inflammation.

Effect of storage of plasma in the presence of red blood cells and platelets: re-evaluating the shelf life of whole blood.

Background: There is renewed interest in administering whole blood (WB) for the resuscitation of patients with bleeding trauma. The shelf life of WB was established decades ago based on the viability of red blood cells. However, plasma quality during WB storage is not established.

Graft Survival After Penetrating and Endothelial Keratoplasty in Iridocorneal Endothelial Syndrome.

Purpose: To compare the survival of a first penetrating keratoplasty (PK) or endothelial keratoplasty (EK) for iridocorneal endothelial (ICE) syndrome with transplant survival in Fuchs endothelial dystrophy (FED) and pseudophakic bullous keratopathy (PBK).

Methods: We compared graft survival of PK and EK for ICE syndrome for 2 time periods. We then compared graft survival in ICE syndrome with graft survival in FED and PBK.

Comparison of automated and manual methods for washing red blood cells.

Background: We sought to compare the quality of washed red blood cells (RBCs) produced using the ACP215 device or manual methods with different combinations of wash and storage solutions. Our aim was to establish manual methods of washing that would permit a shelf life of more than 24 hours.

Study Design And Methods: Fourteen-day-old RBCs were pooled, split, and washed in one of five ways: 1) using the ACP215 and stored in SAGM, 2) manually washed and stored in saline, 3) manually washed in saline and stored in SAGM, 4) manually washed in saline-glucose and stored in SAGM, and 5) manually washed and stored in SAGM.

Early fibrinogen concentrate therapy for major haemorrhage in trauma (E-FIT 1): results from a UK multi-centre, randomised, double blind, placebo-controlled pilot trial.

Background: There is increasing interest in the timely administration of concentrated sources of fibrinogen to patients with major traumatic bleeding. Following evaluation of early cryoprecipitate in the CRYOSTAT 1 trial, we explored the use of fibrinogen concentrate, which may have advantages of more rapid administration in acute haemorrhage. The aims of this pragmatic study were to assess the feasibility of fibrinogen concentrate administration within 45 minutes of hospital admission and to quantify efficacy in maintaining fibrinogen levels ≥ 2 g/L during active haemorrhage.

Superior survival of cultured human reticulocytes following transfusion into mice.

The generation of cultured red blood cells from stem cell sources may fill an unmet clinical need for transfusion-dependent patients, particularly in countries that lack a sufficient and safe blood supply. Cultured red blood cells were generated from human CD34 cells from adult peripheral blood or cord blood by expansion, and a comprehensive survival comparison with standard red cell concentrates was undertaken. Significant amplification (>10-fold) was achieved using CD34 cells from both cord blood and peripheral blood, generating high yields of enucleated cultured red blood cells.

Sequential Bilateral Corneal Transplantation and Graft Survival.

Purpose: To investigate graft survival and rejection following sequential bilateral corneal transplantation.

Design: Retrospective cohort study.

Methods: The study included patients with Fuchs endothelial dystrophy (FED), pseudophakic bullous keratopathy (PBK), or keratoconus who had undergone a penetrating keratoplasty (PK), endothelial keratoplasty (EK), or deep anterior lamellar keratoplasty (DALK) between 1999 and 2012.

UK Renal Registry 17th Annual Report: Chapter 11 Centre Variation in Access to Renal Transplantation in the UK (2008-2010).

Background: Renal transplantation is recognised as being the optimal treatment modality for many patients with established renal failure. This analysis aimed to explore inter-centre variation in access to renal transplantation in the UK.

Methods: Transplant activity and waiting list data were obtained from NHS Blood and Transplant, demographic and laboratory data were obtained from the UK Renal Registry.

Storage characteristics of cord blood progenitor cells: report of a multicenter study by the cellular therapies team of the Biomedical Excellence for Safer Transfusion (BEST) Collaborative.

Background: Most hematopoietic progenitor cell (HPC) products are infused or processed shortly after collection, but in some cases this may be delayed for up to 48 hours. A number of variables such as temperature and cell concentration are of critical importance for the integrity of HPCs during this time.

Study Design And Methods: We evaluated critical variables using cord blood HPC units that were divided equally and stored at 4 °C versus room temperature (RT) for up to 96 hours.

Retransplantation for graft failure in chronic hepatitis C infection: a good use of a scarce resource?

Aim: To investigate the outcome of patients with hepatitis C virus (HCV) infection undergoing liver retransplantation.

Methods: Using the UK National Registry, patients undergoing liver transplantation for HCV-related liver disease were identified. Data on patient and graft characteristics, as well as transplant and graft survival were collected to determine the outcome of HCV patients undergoing retransplantation and in order to identify factors associated with transplant survival.

The importance of cold and warm cardiac ischemia for survival after heart transplantation.

Background: Ischemia time is a risk factor for mortality after heart transplantation that can be influenced by organizational factors such as transport arrangements and organ allocation.

Methods: We used the United Kingdom Cardiothoracic Transplant Audit database to analyze the outcome of 1491 first isolated orthotopic adult heart transplants performed between April 1995 and March 2004. Ischemia time and its components (transport time and surgical implant time) were related to 30-day mortality using a multivariable logistic regression model.