Human umbilical cord blood mononuclear cells (HUCB) have been shown to have a therapeutic role in different models of central nervous system (CNS) damage, including stroke. We evaluated the possible therapeutic potential of HUCB in P7 rats submitted to the Rice-Vannucci model of neonatal hypoxic-ischemic (HI) brain damage. Our results demonstrated that intraperitoneal transplantation of HUCB, 3 h after the HI insult, resulted in better performance in two developmental sensorimotor reflexes, in the first week after the injury. We also showed a neuroprotective effect in the striatum, and a decrease in the number of activated microglial cells in the cerebral cortex of treated animals. We suggest that HUCB transplantation might rescue striatal neurons from cell death after a neonatal HI injury resulting in better functional recovery.

In the human brain, the transformation of radial glial cells (RGC) into astrocytes has been studied only rarely. In this work, we were interested in studying the morphologic aspects underlying this transformation during the fetal/perinatal period, particularly emphasizing the region-specific glial fiber anatomy in the medial cortex. We have used carbocyanine dyes (DiI/DiA) to identify the RGC transitional forms and glial fiber morphology. Immunocytochemical markers such as vimentin and glial fibrillary acidic protein (GFAP) were also employed to label the radial cells of glial lineage and to reveal the early pattern of astrocyte distribution. Neuronal markers such as neuronal-specific nuclear protein (NeuN) and microtubule-associated protein (MAP-2) were employed to discern whether or not these radial cells could, in fact, be neurons or neuronal precursors. The main findings concern the beginning of RGC transformation showing loss of the ventricular fixation in most cases, followed by transitional figures and the appearance of mature astrocytes. In addition, diverse fiber morphology related to depth within the cortical mantle was clearly demonstrated. We concluded that during the fetal/perinatal period the cerebral cortex is undergoing the final stages of radial neuronal migration, followed by involution of RGC ventricular processes and transformation into astrocytes. None of the transitional or other radial glia were positive for neuronal markers. Furthermore, the differential morphology of RGC fibers according to depth suggests that factors may act locally in the subplate and could have a role in the process of cortical RGC transformation and astrocyte localization. The early pattern of astrocyte distribution is bilaminar, sparing the cortical plate. Few astrocytes (GFAP+) in the upper band could be found with radial processes at anytime. This suggests that astrocytes in the marginal zone could be derived from different precursors than those that differentiate from RGCs during this period.

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In order to identify latent bioelectrical oscillators, 15 normal subjects (aged 9-17 years, 8 males, 7 females) were subjected to intermittent photic stimulation. The EEG amplitude spectra corresponding to the 11 fixed frequencies of stimulation presented (3-24 Hz) were combined to form "profiles" of the driving reaction in the right occipital area. The driving response varied with frequency, and was demonstrable in 70-100% of cases (using as criterion peak amplitudes 20% larger than those of the neighbors). The strongest responses were observed at the frequency closest to the alpha peak of the resting EEG. A secondary profile maximum was in the theta band. In 10 subjects, this maximum exceeded half the alpha peak (with an average of 72.4% of the alpha peak), while in the resting spectra, theta amplitudes were much lower than the alpha maxima. This responsiveness in theta activity seems to be characteristic of prepubertal and pubertal subjects. The profiles and resting EEG spectra showed a highly significant Pearson's correlation, with the peak in the theta band of the profiles being the main difference observed between them. The correlation coefficient was significantly correlated with the ratio of the maxima in the theta and alpha bands (R = -0.77, P<0.001). The correlation coefficient between profile and resting spectrum may be a useful indicator in screening methods used to reveal latent cerebral oscillators. Profiles for the second and third harmonics were correlated with those of the first harmonic (fundamental frequency), when considering the corresponding EEG frequencies. Peak frequencies in all three profiles were close to those of the individual's background alpha rhythm, and peak amplitudes in higher harmonics were not much lower than those of the fundamental frequency (mean values of 84 and 63%, for second and third harmonics, respectively).