Years Of Postnatal Development Research Articles

GFAP expression in the brain during human postnatal development

AbstractGlial fibrillary acidic protein (GFAP) immunohistochemistry was investigated in the developing human brain using two measures; the number of GFAP‐positive cells (density, GFAP+/mm2), and a reactivity score (R‐score), which we recently introduced to indicate astrogliosis, with scores ≥120 indicative of pathological processes. The primary aim was to report on GFAP expression and cell soma size in 26 microscopically defined regions of the amygdala, basal ganglia, cerebellum, hippocampus and medulla, and to determine whether they are affected by postconceptional age (PCA) from 40 to 83 weeks. The secondary aim was to determine if GFAP expression differs according to the classification of sudden infant death syndrome (SIDS) as opposed to infant deaths of known causes, or for the presence of major SIDS risk factors of male sex, cigarette smoke exposure, upper respiratory tract infection (URTI), bed‐sharing and prone sleeping. The cerebellar molecular layer was void of GFAP+ cells, while the internal granular layer (IGL) had the highest density, with >60% of infants having an R‐Score >120. GFAP expression decreased with increasing PCA in the entorhinal and temporal cortex, subiculum and regions of the cerebellum and medulla. GFAP cell soma size corresponded with astrogliosis score and no effect of PCA was evident. Various region‐dependent GFAP expressional differences were seen according to SIDS classification and the risk factors studied. The findings indicate that the density of GFAP decreases in specific regions of the brain within the first year of postnatal development, and that reactive astrocytes are common, particularly within the early postnatal months.

Multi-Regression based supervised sample selection for predicting baby connectome evolution trajectory from neonatal timepoint.

The connectional map of the baby brain undergoes dramatic changes over the first year of postnatal development, which makes its mapping a challenging task, let alone learning how to predict its evolution. Currently, learning models for predicting brain connectomic developmental trajectories remain broadly absent despite their great potential in spotting atypical neurodevelopmental disorders early. This is most likely due to the scarcity and often incompleteness of longitudinal infant neuroimaging studies for training such models. In this paper, we propose the first approach for progressively predicting longitudinal development of brain networks during the postnatal period solely from a baseline connectome around birth. To this end, a supervised multi-regression sample selection strategy is designed to learn how to identify the best set of neighbors of a testing baseline connectome to eventually predict its evolution trajectory at follow-up timepoints. However, given that the training dataset may have missing samples (connectomes) at certain timepoints, this may affect the training of the predictive model. To overcome this problem, we perform a low-rank tensor completion based on a robust principal component analysis to impute the missing training connectomes by linearly approximating similar complete training networks. In the prediction step, our sample selection strategy aims to preserve spatiotemporal relationships between consecutive timepoints. Therefore, the proposed method learns how to identify the set of the local closest neighbors to a target network by training an ensemble of bidirectional regressors leveraging temporal dependency between consecutive timepoints with a recall to the baseline observations to progressively predict the evolution of a testing network over time. Our method achieves the best prediction results and better captures the dynamic changes of each brain connectome over time in comparison to its ablated versions using leave-one-out cross-validation strategy.

Features of morphological changes of peridont tissues in patients with β-thalassemia major

Relevance of the research topic.Β-thalassemia major is a hereditary blood disease, the functional manifestation of which is the defciency of synthesis of the β hemoglobin chain, leading to the occurrence of severe hypochromic anemia in the frst two years of postnatal development. Treatment of the disease requires a lifelong transfusion, which leads to the iron overload disorder. The development of hemosiderosis contributes to the chronization of inflammatory processes and cellular modifcation of organs and tissues, including the oral cavity. Inevitable metabolic disorders that occur during β-thalassemia prevents the full functional participation of macro- and microelements in metabolic processes in the periodontium, which is necessary for collagen modifcation.Purpose.The aim of the study is to identify the features of morphological changes in the gingival mucous membrane in patients with β-thalassemia major with generalized gingivitis in remission stage in order to determine potential points of application of additional corrective therapy. Materials and methods. The study included 12 patients with β-thalassemia major (the average age of the subjects was 15 ± 0.1 years). Dental examination was carried out in accordance with the recommendations of the WHO, 1990. Araldite-Epon blocks were formed according to the generally accepted method. The production of semi- (1-2 microns) and ultrathin (35-70 nm) sections were obtained using a Leica EM UC7 ultramicrotome (Germany). Semi-thin sections (1-2 μm) were stained by trichrome staining according to F. D'Amico (2005). Viewing of stained and unstainted ultrathin sections was performed on an JEM-1400 electron microscope (Japan) at an accelerating voltage of 80-120 kV.Results.Periodontal modifcation in the remission stage of catarrhal-sclerosing gingivitis in patients with β – thalassemia major is morphologically marked by disorganization of the connective tissue with destruction of the collagen structures and defciency of the presence of immunocompetent cells in its matrix. Elements of dense connective tissue spread from the papillary part of the lamina propria, where elements of loose connective tissue are usually located. The accumulation of immunocompetent cells in the composition of the connective tissue and in the vascular elements's lumen (both blood and lymphatic) of the lamina propria is not detected.Summary.An inflammatory periodontal disease in patients with β-thalassemia major is characterized by marked disorganization of the connective tissue, which requires therapy aimed to develop a correction of mineral metabolism, antioxidant protection and activate the mechanisms of anti-infective protection of the periodontal tissues.

A Hybrid Multishape Learning Framework for Longitudinal Prediction of Cortical Surfaces and Fiber Tracts Using Neonatal Data.

Dramatic changes of the human brain during the first year of postnatal development are poorly understood due to their multifold complexity. In this paper, we present the first attempt to jointly predict, using neonatal data, the dynamic growth pattern of brain cortical surfaces (collection of 3D triangular faces) and fiber tracts (collection of 3D lines). These two entities are modeled jointly as a multishape (a set of interlinked shapes). We propose a hybrid learning-based multishape prediction framework that captures both the diffeomorphic evolution of the cortical surfaces and the non-diffeomorphic growth of fiber tracts. In particular, we learn a set of geometric and dynamic cortical features and fiber connectivity features that characterize the relationships between cortical surfaces and fibers at different timepoints (0, 3, 6, and 9 months of age). Given a new neonatal multishape at 0 month of age, we hierarchically predict, at 3, 6 and 9 months, the postnatal cortical surfaces vertex-by-vertex along with fibers connected to adjacent faces to these vertices. This is achieved using a new fiber-to-face metric that quantifies the similarity between multishapes. For validation, we propose several evaluation metrics to thoroughly assess the performance of our framework. The results confirm that our framework yields good prediction accuracy of complex neonatal multishape development within a few seconds.

Follow-up IN CHILDRENS OF INTRAUTERINE VIRAL INFECTIONS

The health status in term and premature newborns with intrauterine viral infections up to 3 years of postnatal development was studied. Indices of health state in premature newborns, rates of psychomotor and speech development differ from corresponding indices of term infants and demand of timely treatment-rehabilitation measures.

Prefrontal GABA A receptor α-subunit expression in normal postnatal human development and schizophrenia

Cortical GABA deficits that are consistently reported in schizophrenia may reflect an etiology of failed normal postnatal neurotransmitter maturation. Previous studies have found prefrontal cortical GABA A receptor α subunit alterations in schizophrenia, yet their relationship to normal developmental expression profiles in the human cortex has not been determined. The aim of this study was to quantify GABA A receptor α-subunit mRNA expression patterns in human dorsolateral prefrontal cortex (DLPFC) during normal postnatal development and in schizophrenia cases compared to controls. Transcript levels of GABA A receptor α subunits were measured using microarray and qPCR analysis of 60 normal individuals aged 6 weeks to 49 years and in 37 patients with schizophrenia/schizoaffective disorder and 37 matched controls. We detected robust opposing changes in cortical GABA A receptor α1 and α5 subunits during the first few years of postnatal development, with a 60% decrease in α5 mRNA expression and a doubling of α1 mRNA expression with increasing age. In our Australian schizophrenia cohort we detected decreased GAD67 mRNA expression ( p = 0.0012) and decreased α5 mRNA expression ( p = 0.038) in the DLPFC with no significant change of other α subunits. Our findings confirm that GABA deficits (reduced GAD67) are a consistent feature of schizophrenia postmortem brain studies. Our study does not confirm alterations in cortical α1 or α2 mRNA levels in the schizophrenic DLPFC, as seen in previous studies, but instead we report a novel down-regulation of α5 subunit mRNA suggesting that post-synaptic alterations of inhibitory receptors are an important feature of schizophrenia but may vary between cohorts.

Development of human visual cortex: A balance between excitatory and inhibitory plasticity mechanisms

Formation of neural circuitry in the developing visual cortex is shaped by experience during the critical period. A number of mechanisms, including N-methyl-D-aspartate (NMDA) receptor activation and gamma-aminobutyric acid (GABA)-mediated inhibition, are crucial in determining onset and closure of the critical period for visual plasticity. Animal models have shown that a threshold level of tonic inhibition must be reached for critical period plasticity to occur and that NMDA receptors contribute to Hebbian synaptic plasticity in the developing visual cortex. There are a number of developmental changes in these glutamatergic and GABAergic mechanisms that have been linked to plasticity; however, those changes have been shown only in animal models, and their development in the human visual cortex is not known. We have addressed this question by studying the expression of the major glutamatergic receptors, GABA(A) receptors, and glutamic acid decarboxylase (GAD) isoforms during the first 6 years of postnatal development of human visual cortex. There are significant changes in the expression of these proteins during postnatal development of human visual cortex. The time course of the changes is quite prolonged and suggests that it may set the pace for the prolonged critical period in human visual development. The changes also affect the nature of spatial and temporal integration in visual cortical neurons and thereby contribute to the maturation of visual functions.

Radiology of postnatal skeletal development. VII. The scapula.

Twenty-four pairs of scapulae from fetal specimens and 35 pairs of scapulae from postnatal cadavers ranging in age from full-term neonates to 14 years, were studied morphologically and roentgenographically. Air-cartilage interfacing was used to demonstrate both the osseous and cartilaginous contours. When the entire chondro-osseous dimensions, rather than just the osseous dimensions, were measured, the scapula had a height-width ratio ranging from 1.36 to 1.52 (average 1.44) during most of fetal development. The exceptions were three stillborns with camptomelic, thanatophoric, and achondrogenic dwarfism in which the ratio averaged 0.6. At no time during fetal development was the glenoid cavity convex; it always had a concave articular surface. However, the osseous subchrondral countour was often flat or slightly convex. In the postnatal period the height-width ratio averaged 1.49. The ratio remained virtually unchanged throughout skeletal growth and maturation. In a patient with unilateral Sprengel's deformity the ratio for the normal side was 1.5, while the abnormal was 1.0. The cartilaginous glenoid cavity was always concave during postnatal development, even in the specimens with major structural deformities, although the subchondral osseous contour was usually flat or convex during the first few years of postnatal development. Ossification of the coracoid process began with the development of a primary center at three to four months. A bipolar physis was present between the primary coracoid center and the primary scapular center until late adolescence.