The selection of outcomes is a critically important decision when designing randomised controlled trials (RCTs). Informed clinical decisions can only be based on the results of RCTs that have measured outcomes of importance to both clinicians and patients. It can be difficult to know which outcomes should be measured in RCTs. Some groups advocate core outcome sets, which are a minimum set of outcomes that should be measured, and reported, in all clinical trials in a given condition. These increase the likelihood that important outcomes are measured, reduce nonuniformity between studies, and reduce the risk of outcome reporting bias. We systematically reviewed studies that determined which outcomes to measure in clinical trials in children, and found that such work had been conducted in only few conditions, and the quality of existing work was variable. Few studies used structured consensus techniques to reach agreement about which outcomes to measure in trials, and parents were seldom involved. No studies included children. One condition in which there were no robust recommendations about which outcomes to measurein RCTs was childhood asthma, which is a condition of considerable global importance. We subsequently aimed to assess whether the absence of a core outcome set for RCTs of children with asthma meant that certain outcome domains were measured less frequently than others, and whether there was nonuniformity between studies in terms of outcomes selected. We conducted a systematic review of RCTs of children with asthma, published between January 1988 and December 2007, and found that the included studies focussed on short-term disease activity, but quality of life, functional status, and long-term outcomes were infrequently measured. Certain outcomes were measured and reported in various ways. We recommended that a core outcome set should be developed for childhood asthma, using structured consensus techniques, such as the Delphi process. In order to aid the development of such a core set, we first systematically reviewed studies that used the Delphi process to determine which outcomes to measure in clinical trials. We observed variations in the methodology used, identified potential sources of bias, and provided recommendations about how such studies could be conducted and reported. In order to develop a core outcome set for childhood asthma, we used a Delphi process to ascertain the views of 46 clinicians, and around 100 parents and young people, about which outcomes are most important and relevant from their perspective, when making shared decisions about regular therapies which control asthma. The most important outcomes were symptoms, exacerbations, and quality of life. Although consensus still needs to be reached amongst other groups of individuals involved in clinical trials, we conclude that these outcomes should be measured, and reported, in all RCTs that aim to evaluate the effectiveness of regular therapies for children and young people with asthma.

No description available.

This thesis examines the role of vision in language development by focusing on: first, the understanding blind infants have of objects, actions/events and the way they start to talk about these aspects of their environment; and, second, the ways visual information contributes to conceptual and lexical development in sighted infants. Until recently, research has predominantly focused on infants' understanding of objects and their understanding of actions/events has been neglected. Since individuals who are blind predominantly have access to temporal, rather than spatial infomation and so are better able to process information about actions and events rather than objects, this bias seems to have led to the conclusion that an absence of visual information results in a cognitive deficit. Six blind/severely visually impaired infants and their sighted controls were studied for around a year using a range of quasi-experimental, parental report and observational techniques. The studies found little difference between the blind and sighted infants in the age of onset or rate at which first words are produced. However, blind infants were found to be delayed in the age at which they were able to comprehend and produce labels for objects and they produced few words for concrete, discrete objects. The finding that the blind infants were able to categorize objects/actions as well as generalise and extend their words calls into question Dunlea's (1989) claim that an absence of visual information leads to a cognitive deficit. It is argued that blind infants can make their way into language using a route which is merely one end of a spectrum of routes used by sighted infants. Implications are discussed for theories of lexical development (multiroute model, developmental lexical principles framework and the social-pragmatic framework) as well as for possible strategies facilitate conceptual and lexical development in blind/SVI and sighted infants.

Constraint induced movement therapy (CIMT) which is supported by motor learning theory has demonstrated promising results in improving upper limb function in hemiplegic cerebral palsy (HCP). However, its effectiveness within the NHS where children in the UK usually receive their therapy is little understood. To provide clarification, the author conducted a randomised controlled trial (n = 62) in 16 NHS paediatric community therapy services which compared the feasibility and effectiveness of a novel approach (prolonged restraint) of CIMT with usual NHS practice, in the young child with HCP. The primary outcome was bimanual performance measured with the Assisting Hand Assessment (AHA). Immediately post-intervention both groups changed and although there was not a statistically significant group difference the prolonged restraint methodology resulted in a larger effect (0.5 versus 0.2). The novel approach was safe, feasible, and acceptable to families and a more effective method of treatment delivery. The trial findings were combined in a systematic review and meta-analysis with a similar study and a treatment effect of 0.92 AHA logits was demonstrated. This is compatible with the smallest detectable difference (0.97 logits) indicating actual change in bimanual performance. The short-term efficacy, excellent recruitment and retention rates and acceptability of the trial procedures provides support for the trial feasibility and the need for a definitive investigation.

Biliary atresia is a common form of paediatric liver disease, with progressive, inflammatory obliteration of the biliary tree, leading to liver failure early in life. Mutations in PKHD1, encoding the ciliary protein fibrocystin, are associated with autosomal recessive polycystic kidney disease (ARPKD), a ciliopathy with clinical features that resemble biliary atresia. The hepatic developmental defects detectable in a significant number of infants with ARPKD are thought to be caused by dysfunction in the structure and function of primary cilia. The pathogenetic mechanism of both disorders is thought to be dysregulation of epithelial cell growth and tubulomorphogenesis. Preliminary investigations uncovered an association of PKHD1 sequence variants in a subset of biliary atresia patients with renal cysts, promoting further investigation to determine the functional role of fibrocystin in epithelial cells from renal and biliary tubules. Immunohistochemical studies, using a monoclonal antibody raised against wildtype fibrocystin, showed that it localises specifically to intrahepatic bile ducts. Absence of fibrocystin staining in end-stage liver tissue reflects ongoing damage to the intrahepatic biliary tree, rather than a phenomenon specific to biliary atresia. Studies utilising the Pkhd1 \(^{del2/del2}\) mouse model of ARPKD revealed 17β-estradiol sensitive centrosomal overduplication underlies the dysregulation of epithelial cell growth in renal tubules, however this does not appear to be in synergy with \(Pkhd1\) knockdown. Therefore, it remains uncertain whether sequence variants of PKHD1 are associated with biliary atresia.

Liver disease in children is rare but often serious, life long, and in many cases leads to death. Advances in diagnosing and treating liver disease (including liver transplant) have improved the outlook for children in many cases however little is known about the molecular pathogenesis of the disease, an understanding of which may identify specific therapeutic options. The aim of this thesis is to investigate the molecular genetics of rare liver disorders as the first step in advancing the understanding of liver disease pathogenesis. As a paediatric hepatologist I have identified cohorts of children in whom there is paucity of knowledge about the disease pathogenesis. I have studied three conditions in detail to encompass different clinical presentations. Chapter 3 summarises the investigation of the multisystem disorder, phenotypic diarrhoea of infancy (PDI), which causes cirrhosis or liver failure. Autozygosity mapping was used to identify the gene TTC37 in which mutations are associated with the PDI disease phenotype. Further work is now required to characterise TTC37, and use knockdown studies to identify whether TTC37 mutations are causative of the PDI phenotype. Chapter 4 describes the molecular genetic investigation of Jeune asphyxiating thoracic dystrophy (JATD), a chondrodysplasia with extra skeletal manifestations including hepatic ductal plate malformation and renal cyst development. Using autozygosity mapping, IFT80 was dentified in which mutations are associated with the JATD disease phenotype in 4% of ases. The diverse linical phenotype of JATD limits the utility of utozygosity mapping s it suggests there is genetic heterogeneity. The identification of IFT80 has led to JATD eing classified as a ciliopathy. Chapter 5 is the first description of eonatal liver failure to be associated with variants in ABCB11 which previously have only been associated with chronic liver disease and liver disease in pregnancy. This thesis has described the identification of the molecular genetic basis of rare causes of paediatric liver disease which has provoked many additional research questions. Future work will be to extend our knowledge of molecular genetics to all aspects of paediatric liver physiology so to classify disease according to the molecular pathogenesis such as a ciliopathy or bile salt transport defect.

A wider understanding of the impact of each of the dietary components on blood phenylalanine concentrations in PKU may lead to improvements in management. Knowledge of the effects of such rigorous diet therapy on feeding behaviour is also important. In a series of studies, the effect of a number of dietary factors on plasma phenylalanine control and of diet on feeding behaviour was systematically investigated. The key findings were: 1) there is wide variability in plasma phenylalanine concentrations which were not reflected in a single early morning phenylalanine measurement; 2) plasma phenylalanine concentrations were more influenced by the timing and dosage of protein substitute than by total energy or excess natural protein intake from ‘freely’ allowed foods; 3) repeated 4 hourly administration of protein substitute throughout 24-hours markedly reduced phenylalanine variability and led to lower phenylalanine concentrations; 4) ‘free’ use of fruits and vegetables containing phenylalanine between 51-100 mg/100g did not adversely affect plasma phenylalanine control; and 5) feeding problems were common, with almost 50% of young children with PKU exhibiting at least 3 feeding problems. These findings in PKU are important in the understanding of feeding behaviour; the interpretation of plasma phenylalanine concentrations; they increase and rationalise the range of ‘free’ foods; and will reduce 24-hour plasma phenylalanine variability, and thus, possibly increase dietary phenylalanine tolerance.

Introduction: Despite the importance of pharmacokinetic (PK) information for patient management there are low numbers of paediatric PK studies and little guidance available on optimum study design and conduct. Method: Drawing on Implementation Science, a mixed-methods study was conducted, including a scoping review (SR) (PK literature: 1990-2015) and quantitative and qualitative inquiry (stakeholders: lay population, service users and health-care professionals). Aim: to explore the feasibility and acceptability of paediatric PK research. Results: The SR (203 papers) highlighted significant problems with participant recruitment, retention and sampling. Stakeholders (n=240) added insight into these phenomenon, with lack of research staff, additional blood-sampling and appointments highlighted as significant barriers to recruitment and conduct. Facilitators included sensitivity and timeliness of approach, communication, involvement of child/young person (CYP) in decision-making, engagement between research and clinical teams, reassurance of safety, pain minimisation, and avoidance/reduction of burden to the CYP and family. Dedicated research support was viewed as critical to success. Discussion: PK research was viewed as feasible and acceptable by service users and health professionals, even in the context of critical illness. Novel, evidence-based, patient-centred, recommendations for future PK study conduct and design have been generated which are applicable for those designing, approving and implementing PK research.

Infancy is a time of rapid physiological (e.g. anthropometric, immunological and neurological) development. Hence, during this period of life nutritional requirements are at their highest in relation to body mass. There is a paucity of data with respect to the nutritional quality of complementary foods manufactured in the UK for infants and young children. The primary objective of this study was to examine the nutritional value of ‘ready to feed‘ complementary infant foods on the UK market in order to ascertain their suitability, relative to dietary guidelines, for the target group. Quantitative analysis was conducted on eight different products representing four popular commercial brands (meat and vegetable based) currently on sale in the UK for infants aged between 6-12 months. The chemical analyses conducted included Kjeldhal for protein, acid hydrolysis and extraction for fat, phenol sulphuric acid for carbohydrate and AOAC 985.29 for fibre. The results of these studies were referenced to the Recommended Nutrient Intake (RNI) values for 6 to 9 months old children, and a listing of the entire daily intake of nutrients was composed taking into consideration the nutrient and energy intake from milk consumption in order to (1) accurately estimate the daily intake of these nutrients derived from commercial infant food consumption, and (2) ascertain their nutritional suitability relative to dietary guidelines for the 6-9 month age group. The only significant difference found between different product varieties (meat and vegetable-based) was with respect to the protein content (p = 0.04) per 100 g of food. The experimentally determined concentrations of macronutrients (g/100 kcal) were compared to the declared values provided by the manufacturers on the product labels and, despite some variations, the values obtained comply with regulatory requirements (Commission Directive 2006/125/EC). The total daily intake of fat (27.0 g/day), based on the menu composed from commercial complementary food, is suggested to exceed the Dietary Reference Values (DRVs) for fat (31%), if the intake of snacks and desserts are incorporated. The aforementioned results imply that the formulations of the recipes, based on a standard commercial menu, are of significant importance in relation to the nutritional quality of the diet of infants. In terms of elemental analysis, the concentrations of up to twenty (essential and non-essential) elements in a selected range of sixteen different products representing meat, poultry, fish and vegetable base varieties were established by ICP-OES and ICP-MS. Six major essential elements, namely: calcium, iron, magnesium, potassium, sodium and zinc were measured by ICP-OES. The concentrations of six essential trace elements (selenium, molybdenum, cobalt, copper, chromium, manganese) and eight non-essential, potentially toxic, elements (arsenic, barium, nickel, cadmium, antimony, lead, mercury, aluminium) in chicken and fish-based varieties were determined by ICP-MS due to the higher sensitivity required. Based on the results of elemental analysis, there was also some evidence of a lack of attention to micro-nutrient interactions in food. With reference to the guidelines, the RNI values for 6 to 9 month olds, all samples provided less than 20% of RNI values except for potassium (20%). In terms of the risk of exposure to toxicity, the concentration of non-essential elements in ready to feed products analysed were not considered to be of concern. With regard to the analyses of vitamins, a novel assay for the simultaneous quantitative determination of riboflavin (B2) and pyridoxine (B6) has been developed. The method involves a mild hydrolysis step, extraction of the supernatant by centrifugation followed by quantitative analysis using UHPLC. Separation of the two water soluble vitamins achieved is excellent and rapid - within one minute whilst the resultant sample is also LC-MS compatible. With respect to vitamin B analyses, despite wide individual differences between brands (p = 6.5e-12), no significant differences were observed in the levels of vitamin B6 between the meat and vegetable-based varieties (p = 0.7) per 100 g of commercial infant food. Vitamin B2 was not detected in any of the samples, where the detection limit was below 0.07μg/mL. In terms of the RNI of vitamin B6 for 6 - 9 month old infants, the complementary infant meal products analysed herein provided less than 15% of the RNI values with mean (SD) values of 12.87 (±4.46) % and 13.88 (±4.97) % for the meat- and vegetable-based recipes, respectively. The estimated total daily intake of vitamins B2 and B6 from the consumption of commercial complementary food was found to be satisfactory and in accordance with the DRVs. The intake of both vitamin B2 and B6 was estimated to be mainly derived from the consumption of formula milk which could be a cause of concern if the quality of an infant‘s milk diet is compromised by an inadequate or lack of supplemented milk intake. All the foregoing results suggest that commercial complementary infant foods on the UK market may not contain minimum levels of micronutrients required for labelling declaration of micronutrient content (Commission Directive 2006/125/EC). An attempt, therefore, was made to optimise the formulated version of the meat based infant food as a baseline and measure the post-process retention of its nutrient content after being subjected to different processing condition in terms of a combination of temperature and time. This was achieved by quantitative analysis of the post-process values of the nutrients in the optimised formula using the aforementioned analytical techniques. The results of this study indicates that careful formulation of the recipes, in the context of new product development, is important; the selection of high quality ingredients and the ratios in which they are used have a direct effect on the nutrient content of the final product. It also indicates that a carefully controlled temperature-time combination, pH, pressure and macroscopic conditions of processing (e.g. controlled leaching) are very important in reducing heat loss and improving the nutritional quality of the food product. This provides opportunities and scope for product optimisation, of ready to eat to eat infant foods, in order to improve their nutritional value.

Congenital heart disease (CHD) is the most common birth defect, causing an important rate of morbidity and mortality. Treatment of CHD requires surgical correction in a significant percentage of cases which exposes patients to cardiac and end organ injury. Cardiac surgical procedures often require the utilisation of cardiopulmonary bypass (CPB), a system that replaces heart and lungs function by diverting circulation into an external circuit. The use of CPB can initiate potent inflammatory responses, in addition a proportion of procedures require a period of aortic cross clamp during which the heart is rendered ischaemic and is exposed to injury. High O2 concentrations are used during cardiac procedures and when circulation is re-established to the heart which had adjusted metabolically to ischaemia, further injury is caused in a process known as ischaemic reperfusion injury (IRI). Several strategies are in place in order to protect the heart during surgery, however injury is still caused, having detrimental effects in patients at short and long term. Remote ischaemic preconditioning (RIPC) is a technique proposed as a potential cardioprotective measure. It consists of exposing a remote tissue bed to brief episodes of ischaemia prior to surgery in order to activate protective pathways that would act during CPB, ischaemia and reperfusion. This study aimed to assess RIPC in paediatric patients requiring CHD surgical correction with a translational approach, integrating clinical outcome, marker analysis, cardiac function parameters and molecular mechanisms within the cardiac tissue. A prospective, single blinded, randomized, controlled trial was conducted applying a RIPC protocol to randomised patients through episodes of limb ischaemia on the day before surgery which was repeated right before the surgery started, after anaesthesia induction. Blood samples were obtained before surgery and at three post-operative time points from venous lines, additional pre and post-bypass blood samples were obtained from the right atrium. Myocardial tissue was resected during the ischaemic period of surgery. Echocardiographic images were obtained before the surgery started after anaesthetic induction and the day after surgery, images were stored for later off line analysis. PICU surveillance data was collected including ventilation parameters, inotrope use, standard laboratory analysis and six hourly blood gas analysis. Pre and post-operative quantitation of markers in blood specimens included cardiac troponin I (cTnI) and B-type natriuretic peptide (BNP), inflammatory mediators including interleukins IL-6, IL-8, IL-10, tumour necrosis factor (TNF-α), and the adhesion molecules ICAM-1 and VCAM-1; the renal marker Cystatin C and the cardiovascular markers asymmetric dymethylarginine (ADMA) and symmetric dymethylarginine (SDMA). Nitric oxide (NO) metabolites and cyclic guanosine monophosphate (cGMP) were measured before and after bypass. Myocardial tissue was processed at baseline and after incubation at hyperoxic concentration during four hours in order to mimic surgical conditions. Expression of genes involved in IRI and RIPC pathways was analysed including heat shock proteins (HSPs), toll like receptors (TLRs), transcription factors nuclear factor κ-B (NF- κ-B) and hypoxia inducible factor 1 (HIF-1). The participation of hydrogen sulfide enzymatic genes, apelin and its receptor were explored. There was no significant difference according to group allocation in any of the echocardiographic parameters. There was a tendency for higher cTnI values and inotropic score in control patients post-operatively, however this was not statistically significant. BNP presented no significant difference according to group allocation. Inflammatory parameters tended to be higher in the control group, however only TNF- α was significantly higher. There was no difference in levels of Cystatin C, NO metabolites, cGMP, ADMA or SDMA. RIPC patients required shorter PICU stay, all other clinical and laboratory analysis presented no difference related to the intervention. Gene expression analysis revealed interesting patterns before and after incubation. HSP-60 presented a lower expression at baseline in tissue corresponding to RIPC patients, no other differences were found. This study provided with valuable descriptive information on previously known and newly explored parameters in the study population. Demographic characteristics and the presence of cyanosis before surgery influenced patterns of activity in several parameters, numerous indicators were linked to the degree of injury suffered by the myocardium. RIPC did not reduce markers of cardiac injury or improved echocardiographic parameters and it did not have an effect on end organ function; some effects were seen in inflammatory responses and gene expression analysis. Nevertheless, an important clinical outcome indicator, PICU length of stay was reduced suggesting benefit from the intervention. Larger studies with more statistical power could determine if the tendency of lower injury and inflammatory markers linked to RIPC is real. The present results mostly support findings of larger multicentre trials which have reported no cardiac benefit from RIPC in paediatric cardiac surgery.