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Query: UMLS:C0029713 (immaturity)
 4,335 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Hyperphenylalaninemia in preterm neonates with heterozygosity for phenylketonuria has previously not been described. We report on a very low birth weight infant, born at a gestational age of 27+5 weeks with a birth weight of 1080 g. Due to a positive family history prenatal diagnosis for phenylketonuria was performed, revealing heterozygosity for classic phenylketonuria. Yet the girl showed hyperphenylalaninemia with a maximum serum phenylalanine concentration of 515 micromol/l on the eighth day of life. Phenylalanine-restrictive parenteral and enteral nutrition was kept from the eighth until the 41st day of life. At term serum phenylalanine concentrations had normalized. We hypothesize that heterozygosity for phenylketonuria may be a risk factor for hyperphenylalaninemia in preterm born infants. Prematurity and the resulting immaturity of liver function with the genetically determined reduced activity of phenylalanine hydroxylase might have caused hyperphenylalaninemia in this girl.
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PMID:Hyperphenylalaninemia in a premature infant with heterozygosity for phenylketonuria. 1534 30

The authors examined 273 newborns weighing less than 1500 g. Their birth weight was very low (1001-1500 g) in 179 but extremely low (< 1000 g) in 94 newborns. Neurological damage was proved in 101 cases (36.99%). The probable reasons for intra- (peri-) ventricular and cerebral hemorrhages in these newborns were the following: respiratory distress syndrome (in 11 cases or 10.89%), mother-fetal infection (in 16 cases or 15.84%), and combination of asphyxia and infection (in 10 cases or 9.9%). The severe degree of prematurity (and immaturity) remained the only causative factor in the rest 64 premature newborns (63.37% of the cases). The results from the distribution of the neurological lesions according to the gestational age were also considered. Usage of monofactorial regression models detected statistically significant differences between asphyxia, infection and brain damage in the newborns of different gestational age.
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PMID:[Intranatal asphyxia, prematurity and congenital infection--their role for brain damage in very low birth weight newborns]. 1551 66

The mechanisms underlying respiratory system immaturity in newborns have been investigated, both in vivo and in vitro, in humans and in animals. Immaturity affects breathing rhythmicity and its modulation by suprapontine influences and by afferents from central and peripheral chemoreceptors. Recent research has moved from bedside tools to sophisticated technologies, bringing new insights into the plasticity and genetics of respiratory control development. Genetic research has benefited from investigations of newborn mice having targeted deletions of genes involved in respiratory control. Genetic variability may govern the normal programming of development and the processes underlying adaptation to homeostasis disturbances induced by prenatal and postnatal insults. Studies of plasticity have emphasized the role of neurotrophic factors. Improvements in our understanding of the mechanistic effects of these factors should lead to new neuroprotective strategies for infants at risk for early respiratory control disturbances, such as apnoeas of prematurity, sudden infant death syndrome and congenital central hypoventilation syndrome.
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PMID:Development of respiratory control: evolving concepts and perspectives. 1594 76

Neonates represent a unique and highly vulnerable patient population. Advances in medical technology that have occurred over the last few decades have improved the survival and quality of life for neonates, particularly those infants born with extreme prematurity or with congenital defects. Although immunologic immaturity and altered cutaneous barriers play some role in the vulnerability of neonates to nosocomial infections, clearly, therapeutic interventions that have proven to be lifesaving for these fragile infants also appear to be associated with the majority of infectious complications resulting in neonatal morbidity and mortality. Rates of infections in neonatal intensive care units (NICUs) have varied from 6% to 40% of neonatal patients, with the highest rates in those facilities having larger proportions of very low-birth-weight infants (birthweight < or =1000 grams) or neonates requiring surgery. Efforts to protect the vulnerable NICU infants include the following: (1) optimal infection control practices, especially good hand hygiene and good nursery design; (2) prudent use of invasive interventions with particular attention to early removal of invasive devices after they are no longer essential; and (3) judicious use of antimicrobial agents, with an emphasis on targeted (narrow spectrum) rather than broad-spectrum antibiotics and appropriate indications (proven or suspected bacterial infections).
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PMID:Health care-associated infections in the neonatal intensive care unit. 1594 43

Apnea, the cessation of respiratory airflow, can begin in many preterm infants in the first week of life and can last until the day of discharge or beyond. This article provides an overview of the complex anatomic, physiological, and developmental mechanisms related to immaturity of both the central nervous system and musculature of the pulmonary system, that contribute to apnea of prematurity. Apnea of prematurity is a diagnosis of exclusion; an array of other conditions and stimuli can also cause apnea, including infections, pulmonary disease, and intracranial pathology. The standard clinical management of apnea, including cutaneous stimulation, methylxanthine therapy, and continuous positive airway pressure or ventilatory support, are discussed as well as newer investigational therapies, such as olfactory stimulation. Emerging evidence on the long-term neurodevelopmental impact of apnea is reviewed. Nursing measures to prevent and manage apnea are reviewed with an emphasis on parent education and preparation for discharge. Apnea resolves in most preterm infants as they approach term corrected gestational age; however, if it does not, options include continued hospitalization or, for infants with stable apnea, discharge with a home apnea monitor.
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PMID:A primer on Apnea of prematurity. 1603 38

In view of the current progress in neonatal intensive care, the present outcome of former preterm neonates does not necessarily reflect the future outcome of today's preterm neonates. In spite of this statistical uncertainty, long-term follow-up studies performed in the past few years point to the fact that the sequelae of prematurity may appear well beyond infancy and may be revealed in varying manners with increasing age. Therefore, a chronological account of the consequences of prematurity is given in this paper, ranging from perinatal mortality/morbidity to the problems to be observed during early childhood, preschool age, and adolescence right up to the long-term sequelae arising in later adulthood. Within this context, a two-fold paradigm shift in neonatology becomes apparent in that, first, the outcome of preterm neonates is not a result of immaturity per se, yet is significantly influenced by the factors leading to preterm birth (inflammation, intrauterine growth restriction), and, second, the sequelae of prematurity do not end with the end of neonatal intensive care, but are greatly modulated by familial conditions in their further course. Even though the statistical data are still subject to changes, these insights form the basis of a structured long-term follow-up of preterm neonates which, after the progressive establishment of acute treatment strategies, will become an increasingly important challenge to neonatology within the framework of paediatrics.
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PMID:[Long-term outcome of preterm neonates: the message behind the statistics]. 1656 39

A substantial number of prematurely born infants will experience later neurodevelopmental challenges. Abnormal development of the cerebellum may be related to some of the impairments exhibited by preterm children. To test the hypothesis that cerebellar development is structurally impaired in preterm infants and associated with adverse outcomes, we studied 83 preterm infants and 13 term controls using volumetric magnetic resonance imaging techniques to obtain cerebellar volumes (CV) at term corrected and subsequent neurodevelopmental assessment at 2 y of age. The preterm group had smaller mean CV at term compared with the term control infants [mean (SD) CV, 22.0 (5.0) versus 23.5 (5.0) cc; mean difference (95% confidence interval), 1.5 (-1.5, 4.4)] although this did not reach statistical significance. Within the preterm group, there was evidence of a reduction in CV related to the presence of white matter injury (WMI) after adjusting for intracranial volume (ICV) [WMI grade 1 versus grade 2: mean (SD) CV, 23.6 (5.0) versus 21.6 (4.5); p = 0.01; WMI grade 1 versus grade 3 and 4: 23.6 (5.0) versus 20.8 (5.6); p = 0.07]. Within the preterm infants, there was no apparent relationship between CV at term and gestational age at birth after adjusting for ICV. At 2 y of age, CV showed a weak correlation with cognitive and motor development, although this was principally mediated by WMI. In conclusion, we found no evidence for a primary impairment in cerebellar development in relation to prematurity, although there was evidence for a secondary effect of cerebral WMI on cerebellar development independent of immaturity.
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PMID:Reduction in cerebellar volumes in preterm infants: relationship to white matter injury and neurodevelopment at two years of age. 1669 Sep 52

Perinatal brain injury in survivors of premature birth has a unique and unexplained predilection for periventricular cerebral white matter. Periventricular white-matter injury (PWMI) is now the most common cause of brain injury in preterm infants and the leading cause of chronic neurological morbidity. The spectrum of chronic PWMI includes focal cystic necrotic lesions (periventricular leukomalacia; PVL) and diffuses myelination disturbances. Recent neuroimaging studies support that the incidence of PVL is declining, whereas focal or diffuse noncystic injury is emerging as the predominant lesion. Factors that predispose to PVL during prematurity include hypoxia, ischemia, and maternal-fetal infection. In a significant number of infants, PWMI appears to be initiated by perturbations in cerebral blood flow that reflect anatomic and physiological immaturity of the vasculature. Ischemic cerebral white matter is susceptible to pronounced free radical-mediated injury that particularly targets immature stages of the oligodendrocyte lineage. Emerging experimental data supports that pronounced ischemia in the periventricular white matter is necessary, but not sufficient to generate PWMI. The developmental predilection for PWMI to occur during prematurity appears to be related to both the timing of appearance and regional distribution of susceptible oligodendrocyte progenitors. Injury to oligodendrocyte progenitors may contribute to the pathogenesis of PWMI by disrupting the maturation of myelin-forming oligodendrocytes. Chemical mediators that may contribute to white-matter injury include reactive oxygen species glutamate, cytokines, and adenosine. As our understanding of the pathogenesis of PWMI improves, it is anticipated that new strategies for directly preventing brain injury in premature infants will develop.
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PMID:Perinatal white matter injury: the changing spectrum of pathology and emerging insights into pathogenetic mechanisms. 1680 10

Respiratory distress syndrome (RDS) is a multifactorial developmental disease caused by lung immaturity and presenting as high-permeability lung edema ("hyaline membrane disease"). It is characterized by a transient deficiency of alveolar surfactant during the first week of life. During the first few days of life, the alveolar surfactant pool size increases up to that in the controls. The allelic variants of the genes encoding the surfactant proteins (SP) SP-A1, SP-A2, SP-B, and SP-C have been associated with RDS. The main SP-A haplotype, interactively with the SP-B Ile131Thr polymorphism and with constitutional and environmental factors, influence the risk. Case reports on mutations with partially functional SP-B have been published. The genetic susceptibility factors depend on the degree of prematurity at birth, consistent with sequential differentiation of the lung and gestation-dependent differences in clinical presentation. The preferentially type 2 cell expressed genes involved in critical functions (such as ATP-binding cassette transporter, ABCA3), those involved in susceptibility to acute lung damage, and those with known susceptibility to other severe lung diseases (such as G protein-coupled receptor for asthma susceptibility, GPR154 alias GPRA) will possibly serve as candidate genes in future studies. RDS associated with near-term and term births may have a different genetic predisposition and pathogenesis compared to RDS after very preterm birth. As we learn more about the molecular consequences of allelic variation, new therapies based on a new generation of surfactant diagnostics and individualized therapies may follow.
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PMID:Genetic basis of respiratory distress syndrome. 1712 71

The brainstem development of infants born between 33 and 38 weeks' gestation is less mature than that of a full-term infant. During late gestation, there are dramatic and nonlinear developmental changes in the brainstem. This translates into immaturity of upper airway and lung volume control, laryngeal reflexes, chemical control of breathing, and sleep mechanisms. Ten percent of late preterm infants have significant apnea of prematurity and they frequently have delays in establishing coordination of feeding and breathing. Unfortunately, there is a paucity of clinical, physiologic, neuroanatomic, and neurochemical data in this specific group of infants. Research focused on this group of infants will not only further our understanding of brainstem maturation during this high risk period, but will help develop focused plans for their management.
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PMID:The late preterm infant and the control of breathing, sleep, and brainstem development: a review. 1714 11


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