Carlos Alberto Baptista

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We generated mice with a null mutation of the forebrain-restricted transcription factor BF-1 to examine its function in brain development. Heterozygous animals have an apparently normal phenotype. Homozygous null BF-1 mutants die at birth and have a dramatic reduction in the size of the cerebral hemispheres. The development of the ventral telencephalon is(More)
To determine the role of cell-cell interactions in Purkinje cell survival and dendritic differentiation, perinatal mouse Purkinje cells were purified, and their development was analyzed in vitro. In isolation at low density, Purkinje cell survival was poor, improved by neuronal contacts, either with purified granule neurons or with Purkinje cells(More)
Cell cycle withdrawal in postmitotic cells involves cyclin-dependent kinase (Cdk) inhibitors that repress cell cycle Cdk activity. During mouse neurogenesis, cortical postmitotic neurons are shown here to accumulate high levels of the p27 Cdk inhibitor compared with their progenitor neuroblasts. Elevated p27 levels in staged embryo brain extracts correlate(More)
With a novel model culture system in which afferents are co-cultured with purified populations of target neurons, we have demonstrated that a target cell within the central nervous system (CNS), the cerebellar granule neuron, poses a "stop-growing signal" for its appropriate afferents, the mossy fibers. To ask whether this stop signal is afferent specific,(More)
Interactions between developing nerve centres and peripheral targets are known to affect neuronal survival and thus regulate the adult number of neurons in many systems. Here we provide evidence that peripheral tissues can also influence cell numbers by stimulating the production of neurons. In the leech Hirudo medicinalis, there is a population of several(More)
INTRODUCTION Joint hypermobility (JH) is an inherited clinical condition with increased joint elasticity in passive movements. In the general population, its frequency, which can be estimated through specific methods, such as the nine-point Beighton hypermobility score (Beighton score) and the self-reported five-part questionnaire for identifying(More)
Leech neurons, like those of other invertebrates and those of vertebrates, undergo specific interactions during development which serve to define their adult morphologies and synaptic connections. We review here several observations and experiments that illustrate these interactions. In particular, we consider how they shape and constrain peripheral(More)
The sixth segmental ganglion in the ventral nerve cord of the leech H. medicinalis contains a bilateral pair of rostral penile evertor motor neurons (RPEs) that in the adult innervate the male genitalia. During embryogenesis, the RPEs extend numerous extraganglionic projections. Only two of these innervate the target and are normally retained in the adult,(More)
In adult Hirudo medicinalis, the segmental ganglia (SG) of the fifth and sixth body segments contain a few hundred more cells than the other segmental ganglia of the body (Macagno, 1980). These ganglia innervate the sex organs and are known as the sex SG. As shown here, these cells are stained by neuron-specific antibodies. Cell counts at several(More)