Fisiopatología de los movimientos oculares en la parálisis cerebral infantil

Cerebral palsy is a permanent and non-progressive brain damage due to various causes affecting a child from the intrauterine life up to the first two years of life. Its most common cause is neonatal hypoxic encephalopathy. The cerebral damage is diffuse so that it is commonly associated with epilepsy, mental retardation, dysarthria, hearing loss and oculomotor abnormalities. Strabismus is found in 50 % of children with cerebral palsy. This prevalence is significantly different from the 2 % incidence of oculomotor abnormalities in the pre-school age, it is noteworthy that strabismus and refractivo errors respond to the classical therapeutic measures

Axonal Control of the Adult Neural Stem Cell Niche

SUMMARYThe ventricular-subventricular zone (V-SVZ) is an extensive germinal niche containing neural stem cells (NSC) in the walls of the lateral ventricles of the adult brain. How the adult brain’s neural activity influences the behavior of adult NSCs remains largely unknown. We show that serotonergic (5HT) axons originating from a small group of neurons in the raphe form an extensive plexus on most of the ventricular walls. Electron microscopy revealed intimate contacts between 5HT axons and NSCs (B1) or ependymal cells (E1) and these cells were labeled by a transsynaptic viral tracer injected into the raphe. B1 cells express the 5HT receptors 2C and 5A. Electrophysiology showed that activation of these receptors in B1 cells induced small inward currents. Intraventricular infusion of 5HT2C agonist or antagonist increased or decreased V-SVZ proliferation, respectively. These results indicate that supraependymal 5HT axons directly interact with NSCs to regulate neurogenesis via 5HT2C

Cellular proliferation in the rat pineal gland during postnatal development

To establish a possible correlation between the rate of cellular proliferation and already documented functional and morphological characteristics of the rat pineal gland during postnatal development, the bromodeoxyuridine labelling method was used to evaluate the fraction of cells at the S phase of the cell cycle in paraffin sections from I-, 7-, 14- and 28-day-old rats. Numerical density, taken as an indirect measure of cell hypertrophy, was also evaluated. During the first week after birth the percentage of S phase-cells in the rat pineal gland sharply decreased from around 9% to 1.3%. A smaller but also significant decrease was found from the 7th to the 14th postnatal day where S phase cells were less than 0.5% of all pineal cells. A very low percentage was also seen in samples from 28-day-old rats. Numerical density, namely, the total number of cells per surface unit of pineal section, decreased from birth to the end of the first month. This decrease was also steeper from birth to the 7th postnatal day than at any other period of the study. These results support the idea that a strong expansion of the cellular population of the rat pineal gland precedes morphological and functional maturation and opens the way to further exploration of the relationship between functional and proliferative responses of the pineal gland

Myelinated Herring bodies in the median eminence of the cat

An electron-microscopic study was carried out on the median eminence of cats during post-natal development. From the moment of birth (observations performed 12 hours later) Herring bodies were seen in the fibrillary layer of the median eminence. At 45 days after birth, myelinated nerve fibres could be observed, some of them containing neurosecretory granules. The number of myelinated fibres in the median eminence increased with age and at 90 days some Herring bodies appeared surrounded by myelin sheaths; these mainly contained neurosecretory granules and a few mitochondria

Fisiopatología de los movimientos oculares en la parálisis cerebral infantil

Cerebral palsy is a permanent and non-progressive brain damage due to various causes affecting a child from the intrauterine life up to the first two years of life. Its most common cause is neonatal hypoxic encephalopathy. The cerebral damage is diffuse so that it is commonly associated with epilepsy, mental retardation, dysarthria, hearing loss and oculomotor abnormalities. Strabismus is found in 50 % of children with cerebral palsy. This prevalence is significantly different from the 2 % incidence of oculomotor abnormalities in the pre-school age, it is noteworthy that strabismus and refractivo errors respond to the classical therapeutic measures