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Functional Development (functional + development)
Selected AbstractsAssessment of gestational age and neuromaturationDEVELOPMENTAL DISABILITIES RESEARCH REVIEW, Issue 1 2005Marilee C. Allen Abstract Neuromaturation is the functional development of the central nervous system (CNS). It is by its very nature a dynamic process, a continuous interaction between the genome and first the intrauterine environment, then the extrauterine environment. Understanding neuromaturation and being able to measure it is fundamental to infant neurodevelopmental assessment. Fetal and preterm neuromaturation has become easier to observe with the advent of prenatal ultrasonography and neonatal intensive care units. A number of measures of degree of fetal maturation have been developed and used to estimate gestational age (GA) at birth. The most reliable measures of GA are prenatal measures, especially from the first trimester. Postnatal GA measurements tend to be least accurate at the extremes of gestation, that is, in extremely preterm and post-term infants. Observations of measures of neuromaturation in infants born to mothers with pregnancy complications, including intrauterine growth restriction, multiple gestation, and chronic hypertension, have led to the discovery that stressed pregnancies may accelerate fetal pulmonary and CNS maturation. This acceleration of neuromaturation does not occur before 30 weeks' gestation and has a cost with respect to cognitive limitations manifested in childhood. The ability to measure fetal and preterm neuromaturation provides an assessment of neurodevelopmental progress that can be used to reassure parents or identify at risk infants who would benefit from limited comprehensive follow-up and early intervention services. In addition, measures of neuromaturation have the potential to provide insight into mechanisms of CNS injury and recovery, much-needed early feedback in intervention or treatment trials and a measure of early CNS function for research into the relationships between CNS structure and function. © 2005 Wiley-Liss, Inc. MRDD Research Reviews 2005;11:21,33. [source] Drosophila neuromuscular synapse assembly and function require the TGF-, type I receptor saxophone and the transcription factor MadDEVELOPMENTAL NEUROBIOLOGY, Issue 2 2003Joel M. Rawson Abstract Transforming growth factor-,s (TGF-,) comprise a superfamily of secreted proteins with diverse functions in patterning and cell division control. TGF-, signaling has been implicated in synapse assembly and plasticity in both vertebrate and invertebrate systems. Recently, wishful thinking, a Drosophila gene that encodes a protein related to BMP type II receptors, has been shown to be required for the normal function and development of the neuromuscular junction (NMJ). These findings suggest that a TGF-,-related ligand activates a signaling cascade involving type I and II receptors and the Smad family of transcription factors to orchestrate the assembly of the NMJ. Here we demonstrate that the TGF-, type I receptor Saxophone and the downstream transcription factor Mothers against dpp (Mad) are essential for the normal structural and functional development of the Drosophila NMJ, a synapse that displays activity-dependent plasticity. © 2003 Wiley Periodicals, Inc. J Neurobiol 55: 134,150, 2003 [source] Beyond licensing and disarming: A quantitative view on NK-cell educationEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 11 2008Petter Brodin Abstract In this article, we will move beyond the current controversy of different models for NK-cell education and instead discuss the properties characterizing MHC class I-guided functional development of NK cells. We will argue that this development, which represents the endpoint of NK-cell education, is a quantitative and dynamic, and perhaps even reversible, process. [source] Activated NKT cells increase dendritic cell migration and enhance CD8+ T cell responses in the skinEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 9 2006Anton Abstract Activated NKT cells produce cytokines such as IL-4 and IFN-, that function locally to influence the strength and functional development of antigen-specific T cells. Here we identify an alternative mechanism by which NKT cells influence the strength of T cell responses: through modulation of peripheral dendritic cell (DC) trafficking. NKT cell activation with ,-galactosylceramide induced high systemic levels of TNF-, that mediated increased DC migration from skin to draining lymph nodes. This increased DC trafficking led to a threefold increase in effector T cell priming and in the immune response elicited to antigen challenge when ,-galactosylceramide was given at the time of immunization of the skin. These studies provide important implications for the use of NKT cell activation strategies to manipulate T cell-mediated responses including responses to cutaneous tumors and graft vs. host disease. [source] Afferent ingrowth and onset of activity in the rat trigeminal nucleusEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 8 2000P. M. E. Waite Abstract A novel in vitro preparation, consisting of the rat brainstem with the trigeminal ganglion attached, has been used to study the anatomical and functional development of the trigeminal nucleus from embryonic day (E)13 to postnatal day (P)6. Neurobiotin injections into the trigeminal ganglion showed that primary afferents had reached the trigeminal tract by E13 and had grown simple, mainly unbranched, collaterals into all levels of the nucleus by E15. By E17, these collaterals were extensively branched, with occasional boutons present. Patches of intense neurobiotin-labelled terminals, corresponding to whisker-related patterns, were first seen at E20 and became clearer over the next few days. Terminal arbours at this stage were relatively localized and densely branched, with many boutons. Responses from the trigeminal nucleus were recorded with suction electrodes, following stimulation of the trigeminal ganglion. Recordings from the main sensory nucleus showed a postsynaptic response was first present at E15. At E16, bath application of AP5 and DNQX showed that the response contained both NMDA and AMPA components, with NMDA predominating (75%). The NMDA : AMPA ratio remained high until P1, then gradually declined to 50% by P6. The postsynaptic response was also reduced by bath application of bicuculline, indicating the presence of a GABAA -mediated excitatory component. GABAergic excitation was present at all ages but was maximal from E20 to P1, the age at which whisker-related patterns are developing. It is hypothesized that both GABAergic excitation and NMDA receptor activation play a role in the consolidation of trigeminal connections, and are thus important in the development of whisker-related patterns. [source] Late postnatal maturation of excitatory synaptic transmission permits adult-like expression of hippocampal-dependent behaviorsHIPPOCAMPUS, Issue 5 2005Theodore C. Dumas Abstract Sensorimotor systems in altricial animals mature incrementally during early postnatal development, with complex cognitive abilities developing late. Of prominence are cognitive processes that depend on an intact hippocampus, such as contextual,configural learning, allocentric and idiocentric navigation, and certain forms of trace conditioning. The mechanisms that regulate the delayed maturation of the hippocampus are not well understood. However, there is support for the idea that these behaviors come "on line" with the final maturation of excitatory synaptic transmission. First, by providing a timeline for the first behavioral expression of various forms of learning and memory, this study illustrates the late maturation of hippocampal-dependent cognitive abilities. Then, functional development of the hippocampus is reviewed to establish the temporal relationship between maturation of excitatory synaptic transmission and the behavioral evidence of adult-like hippocampal processing. These data suggest that, in rats, mechanisms necessary for the expression of adult-like synaptic plasticity become available at around 2 postnatal weeks of age. However, presynaptic plasticity mechanisms, likely necessary for refinement of the hippocampal network, predominate and impede information processing until the third postnatal week. © 2005 Wiley-Liss, Inc. [source] Evidence for the presence of 5,-deiodinase in mammalian seminal plasma and for the increase in enzyme activity in the prepubertal testisINTERNATIONAL JOURNAL OF ANDROLOGY, Issue 4 2000Brzezi, lebodzi Thyroid hormones are critical for structural and functional development of the testis and Sertoli cells are considered true target cells for triiodothyronine (T3). However, the role of thyroid hormones in the adult testis seems to be minimal and the mechanism by which they affect testicular function is not known. Due to the existing blood,testis barrier the concentration of thyroid hormones in seminal plasma is kept lower than in blood plasma. We have found that T3 may reach the testis not only from the circulation but also from local enzymic conversion of thyroxine to T3. The presence of the enzymic activity responsible for thyroxine 5,deiodination and for generating T3 locally was also found in boar's seminal plasma. The seminal plasma 5,-deiodinase (5,-D) appeared to be predominantly the propylthiouracil (PTU)-insensitive type II isoenzyme found, so far, in tissues where it plays a role in paracrine signalling. It contains selenocysteine in its molecule (inhibition by aurothioglucose), and has an apparent Km for reverse-T3 as substrate of 0.36 n M and a Vmax 23.8 fmol I,/mg protein/min. Because the seminal plasma 5,-D is partially, but uncompetitively, inhibited by PTU, the presence in seminal plasma of two 5,-D isoenzymes (type I and II) cannot be excluded. The 5,-D activity in testes increased significantly between week 3 and 4, and this increase was concomitant with increase in testicular size. The relationship between testicular weight gain and age showed a similar characteristic change and corresponded to the change in 5,-D activity. Unlike in rodents, the testis of the prepubertal pig has thyroid hormone receptors in Sertoli cells, and suggests that in growing piglets, testicular 5,-D is a key factor regulating local supply of biologically active T3, and is an essential factor in testicular paracrine function. The present results are the first demonstration and characterization of the 5,-deiodinase in seminal plasma. [source] Effect of manufacturing treatments on the rheological character of Mozzarella cheese made from microfiltration retentate depleted of whey proteins,INTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 6 2001Randall L. Brandsma Low-moisture, part-skim (LMPS) Mozzarella cheeses were made from highly concentrated skim milk microfiltration (MF) retentate and butteroil. Differing combinations of rennet concentration, coagulation temperature and post-coagulation curd cutting time were used, with comparisons made of the rheological and functional characteristics of cheeses during ageing. Lubricated squeezing flow, stress relaxation, melt and stretch measurements demonstrated that commercial LMPS Mozzarella had substantial textural and functional change between 7 and 30 days of age, while the rheological and functional behaviour of LMPS MF Mozzarella (MFM) exhibited substantial change between 30 and 60 days of age. Rennet concentration was the only experimental factor to significantly affect MFM rheological and functional development. The delayed development of MFM was partially attributed to inhibition of normal cheese proteolysis via whey protein (WP) incorporation, lack of starter culture protease, and homogenization of MF cheesemilk. Use of starter culture in MFM led to improved rheological and functional behaviour. [source] The evolutionary history of crustacean segmentation: a fossil-based perspectiveEVOLUTION AND DEVELOPMENT, Issue 6 2005Dieter Waloszek Summary The evolution of segmentation in Crustacea, that is, the formation of sclerotized and jointed body somites and arrangement of somites into tagmata, is viewed in light of historical traits and functional constraints. The set of Early to Late Cambrian ,Orsten' arthropods have informed our current views of crustacean evolution considerably. These three-dimensionally preserved fossils document ancient morphologies, as opposed to purely hypothetical models and, because of the unusual preservation of larval stages, provide us with unparalleled insight into the morphogenesis of body somites and their structural equipment. The variety of evolutionary levels represented in the ,Orsten' including lobopodians, tardigrades, and pentastomids also allows phylogenetic interpretations far beyond the Crustacea. The ,Orsten' evidence and data from representatives of the Lower Cambrian Chengjiang biota in southwestern China, including phylogenetically earlier forms, form the major source of our morphology-based review of structural and functional developments that led toward the Crustacea. The principal strategy of arthropods is the simultaneous development of head somites, as expressed in a basal "head larva," and a successive addition of postcephalic somites from a preterminal budding zone with progressive maturation of metameric structures. This can be recognized in the developmental patterns of extant and fossil representatives of several euarthropod taxa, particularly crustaceans, trilobites, and chelicerates (at least basally). The development of these taxa points to an early somite-poor and free-living hatching stage. Embryonic development to a late stage within an egg, as occurring in recent onychophorans and certain in-group euarthropods, is regarded as achieved several times convergently. [source] | |||||||||||||