Browsing by Author "Valenzuela, CY"

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    Dendritic morphology and orientation of pyramidal cells of the neocortex in two groups of early postnatal undernourished-rehabilitated rats
    (2003) Cordero, ME; Valenzuela, CY; Rodriguez, A; Aboitiz, F
    Postnatal undernutrition in animals and in humans leads to significant reduction in basal dendritic arborization of layer Vth pyramidal cells of the neocortex. Under the hypothesis that there are critical developmental periods for undernutrition to produce alterations in dendritic differentiation, we studied apical dendritic morphology and orientation of pyramidal cells from the deeper layers of the neocortex in rats undernourished until day 10 (UP10), until weaning (UP21) and in a control group (Q. Neurons were stained by the Golgi-Cox method. The main findings are: (i) an increased number of atypically oriented pyramids with apical dendrites extremely short in (UP10) and (UP21) groups and, (ii) the presence of classical pyramids with significantly longer apical dendrites in layers V and VI in (UP10) and (UP21) groups than in the control group (Q. We believe that undernutrition may disturb critically the early postnatal brain development by altering intrinsic factors and extracellular molecular signals that guide and regulate the apical dendritic growth of neocortex large pyramidal cells. (C) 2003 Elsevier Science B.V. All rights reserved.
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    Human Raphe Magnus Nucleus: a morphometric Golgi-Cox study with emphasis on sex differences
    (2001) Cordero, ME; Rodriguez, A; Torres, R; Valenzuela, CY
    The number and proportion of neurons according to their type and size in the Raphe Magnus Nucleus stained by the Golgi-Cox and Nissl methods were compared in male and female infants. Four female/male pairs aged from 2 to 150 days were studied. Wale females showed more neurons than males, males showed a higher proportion of large multipolar (more than 40 mum) and fusiform neurons (more than 20 mum) but not of ovoid neurons (more than 15 mum). These differences varied according to the type of cells and age of infants. Some of these results are similar to those found in the human Median Raphe Nucleus with the same methods. (C) 2001 Elsevier Science B.V. All rights reserved.
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    Sexual dimorphism in number and proportion of neurons in the human median raphe nucleus
    (ELSEVIER, 2000) Cordero, ME; Valenzuela, CY; Torres, R; Rodriguez, A
    The number and proportion of neurons in the median raphe nuclei stained by the Golgy-Cox and Nissl methods was compared in males and females infants. When subjects are matched by age and cause of death the number and proportion of fusiform, ovoid and multipolar cells differs significantly between sexes at different ages. (C) 2000 Elsevier Science B.V. All rights reserved.