35 research outputs found

    Developmental motor problems and health-related quality of life in 5-year-old children born extremely preterm: A European cohort study

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    Aim To measure the association between cerebral palsy (CP) and non-CP-related movement difficulties and health-related quality of life (HRQoL) among 5-year-old children born extremely preterm (<28 weeks gestational age). Method We included 5-year-old children from a multi-country, population-based cohort of children born extremely preterm in 2011 to 2012 in 11 European countries (n = 1021). Children without CP were classified using the Movement Assessment Battery for Children, Second Edition as having significant movement difficulties (<= 5th centile of standardized norms) or being at risk of movement difficulties (6th-15th centile). Parents reported on a clinical CP diagnosis and HRQoL using the Pediatric Quality of Life Inventory. Associations were assessed using linear and quantile regressions. Results Compared to children without movement difficulties, children at risk of movement difficulties, with significant movement difficulties, and CP had lower adjusted HRQoL total scores (beta [95% confidence interval] = -5.0 [-7.7 to -2.3], -9.1 [-12.0 to -6.1], and - 26.1 [-31.0 to -21.2]). Quantile regression analyses showed similar decreases in HRQoL for all children with CP, whereas for children with non-CP-related movement difficulties, reductions in HRQoL were more pronounced at lower centiles. Interpretation CP and non-CP-related movement difficulties were associated with lower HRQoL, even for children with less severe difficulties. Heterogeneous associations for non-CP-related movement difficulties raise questions for research about mitigating and protective factors.Faculdade de Ciencias e Tecnologia, Universidade Nova de Lisboa, Grant/Award Number: SFRH/BPD/117597/2016; Horizon 2020 Framework Programme, Grant/Award Number: No 633724 and No 733280; Seventh Framework Programme, Grant/Award Number: No 25988

    Linkage between fitness of yeast cells and adenylate kinase catalysis

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    Enzymes have evolved with highly specific values of their catalytic parameters kcat and KM. This poses fundamental biological questions about the selection pressures responsible for evolutionary tuning of these parameters. Here we are address these questions for the enzyme adenylate kinase (Adk) in eukaryotic yeast cells. A plasmid shuffling system was developed to allow quantification of relative fitness (calculated from growth rates) of yeast in response to perturbations of Adk activity introduced through mutations. Biophysical characterization verified that all variants studied were properly folded and that the mutations did not cause any substantial differences to thermal stability. We found that cytosolic Adk is essential for yeast viability in our strain background and that viability could not be restored with a catalytically dead, although properly folded Adk variant. There exist a massive overcapacity of Adk catalytic activity and only 12% of the wild type kcat is required for optimal growth at the stress condition 20°C. In summary, the approach developed here has provided new insights into the evolutionary tuning of kcat for Adk in a eukaryotic organism. The developed methodology may also become useful for uncovering new aspects of active site dynamics and also in enzyme design since a large library of enzyme variants can be screened rapidly by identifying viable colonies

    On the dynamics of the adenylate energy system: homeorhesis vs homeostasis.

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    Biochemical energy is the fundamental element that maintains both the adequate turnover of the biomolecular structures and the functional metabolic viability of unicellular organisms. The levels of ATP, ADP and AMP reflect roughly the energetic status of the cell, and a precise ratio relating them was proposed by Atkinson as the adenylate energy charge (AEC). Under growth-phase conditions, cells maintain the AEC within narrow physiological values, despite extremely large fluctuations in the adenine nucleotides concentration. Intensive experimental studies have shown that these AEC values are preserved in a wide variety of organisms, both eukaryotes and prokaryotes. Here, to understand some of the functional elements involved in the cellular energy status, we present a computational model conformed by some key essential parts of the adenylate energy system. Specifically, we have considered (I) the main synthesis process of ATP from ADP, (II) the main catalyzed phosphotransfer reaction for interconversion of ATP, ADP and AMP, (III) the enzymatic hydrolysis of ATP yielding ADP, and (IV) the enzymatic hydrolysis of ATP providing AMP. This leads to a dynamic metabolic model (with the form of a delayed differential system) in which the enzymatic rate equations and all the physiological kinetic parameters have been explicitly considered and experimentally tested in vitro. Our central hypothesis is that cells are characterized by changing energy dynamics (homeorhesis). The results show that the AEC presents stable transitions between steady states and periodic oscillations and, in agreement with experimental data these oscillations range within the narrow AEC window. Furthermore, the model shows sustained oscillations in the Gibbs free energy and in the total nucleotide pool. The present study provides a step forward towards the understanding of the fundamental principles and quantitative laws governing the adenylate energy system, which is a fundamental element for unveiling the dynamics of cellular life

    Phase-Changing Glauber Salt Solution for Medical Applications in the 28&ndash;32 &deg;C Interval

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    (1) Background: The field of medicine requires simple cooling materials. However, there is little knowledge documented about phase change materials (PCM) covering the range of 28 to 40 degrees Celsius, as needed for medical use. Induced mild hypothermia, started within 6 h after birth, is an emerging therapy for reducing death and severe disabilities in asphyxiated infants. Currently, this hypothermia is accomplished with equipment that needs a power source and a liquid supply. Neonatal cooling is more frequent in low-resource settings, where ~1 million deaths are caused by birth-asphyxia. (2) Methods: A simple and safe cooling method suitable for medical application is needed for the 28 to 37.5 &deg;C window. (3) Results: Using empirical experiments in which the ingredients in Glauber salt were changed, we studied the effects of temperature on material in the indicated temperature range. The examination, in a controlled manner, of different mixtures of NaCl, Na2SO4 and water resulted in a better understanding of how the different mixtures act and how to compose salt solutions that can satisfy clinical cooling specifications. (4) Conclusions: Our Glauber salt solution is a clinically suited PCM in the temperature interval needed for the cooling of infants suffering from asphyxia

    High healthcare use at age five in a European cohort of children born very preterm

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    Objectives To describe parent-reported healthcare service use at five years of age in children born very preterm and investigate whether perinatal and social factors and the use of very preterm follow-up services are associated with high service use. Study design We used data from an area-based cohort of births at <32 weeks of gestation from 11 European countries, collected from birth records and parental questionnaires at five years of age. Using the published literature, we defined high use of outpatient/inpatient care (≥4 sick visits to general practitioners, pediatricians, or nurses, ≥3 emergency room visits, or ≥1 overnight hospitalization) and specialist care (≥2 different specialists or ≥3 visits). We also categorized countries as having either high or low rates of children using very preterm follow-up services at five years. Results Overall, 43% of children had high outpatient/inpatient care use, and 48% had high specialist care use during the previous year. Perinatal factors were associated with high outpatient/inpatient and specialist care use, with a more significant association with specialist services. Associations with intermediate parental educational level and unemployment were stronger for outpatient/inpatient services. Living in a country with higher rates of very preterm follow-up service use was associated with lower use of outpatient/inpatient services. Conclusions Children born very preterm had high healthcare service use at five years of age, with different patterns for outpatient/inpatient and specialist care by perinatal and social factors. Longer follow-up of children born very preterm may improve care coordination and help avoid undesirable health service use

    High Healthcare Use at Age 5 Years in a European Cohort of Children Born Very Preterm

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    ObjectivesTo describe parent-reported healthcare service use at age 5 years in children born very preterm and investigate whether perinatal and social factors and the use of very preterm follow-up services are associated with high service use.Study designWe used data from an area-based cohort of births at ResultsOverall, 43% of children had high outpatient/inpatient care use and 48% had high specialist care use during the previous year. Perinatal factors were associated with high outpatient/inpatient and specialist care use, with a more significant association with specialist services. Associations with intermediate parental educational level and unemployment were stronger for outpatient/inpatient services. Living in a country with higher rates of very preterm follow-up service use was associated with lower use of outpatient/inpatient services.ConclusionsChildren born very preterm had high healthcare service use at age 5 years, with different patterns for outpatient/inpatient and specialist care by perinatal and social factors. Longer follow-up of children born very preterm may improve care coordination and help avoid undesirable health service use.</div
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