Cell migration in the postnatal subventricular zone

New neurons are constantly added to the olfactory bulb of rodents from birth to adulthood. This accretion is not only dependent on sustained neurogenesis, but also on the migration of neuroblasts and immature neurons from the cortical and striatal subventricular zone (SVZ) to the olfactory bulb. Migration along this long tangential pathway, known as the rostral migratory stream (RMS), is in many ways opposite to the classical radial migration of immature neurons: it is faster, spans a longer distance, does not require radial glial guidance, and is not limited to postmitotic neurons. In recent years many molecules have been found to be expressed specifically in this pathway and to directly affect this migration. Soluble factors with inhibitory, attractive and inductive roles in migration have been described, as well as molecules mediating cell-to-cell and cell-substrate interactions. However, it is still unclear how the various molecules and cells interact to account for the special migratory behavior in the RMS. Here we will propose some candidate mechanisms for roles in initiating and stopping SVZ/RMS migration

Tomografia computadorizada de torax de alta resolucao em paracoccidioidomicose (blastomicose sul-americana) / Resolution thoracic computed tomography for the diagnosis of south american blastomycosis

A blastomicose sul americana (BSB) e doenca causada pelo fungo Paracoccidioides brasiliensis.Ela acomete principalmente lavradores do sexo masculino, por via inalatoria,acometendo os pulmoes em mais de 80 por cento dos casos na forma cronica do adulto.Foram estudados 30 pacientes com DSA durante tes anos com radiogramas de torax e tomografia computadorizada de torax de alta resolucao(TCTAR) para correlacionar seus achados no sentido de auxiliar o diagnostico.O radiograma confirmou os achados mais comuns:infiltrados reticular e nodular,mais nos campos medios,alguns com consolidacao(19=63 por cento)hiperinsuflacao(20=66 pr cento)e bolhas subpleurais(10=33por cento).A TCTAR mostrou a historia natural da doenca: 1. Via inalatoria:com multiplas areas parenquimatosas semelhates a vidro fosco que podem progredir ou regredir(3=10 por cento) 2. Lesoes parenquimatosas progressivas com nodulos(25=83,3 por cento) consolidacoes irregulares(20=66 por cento, as vezes com insuflacao(22=73 por cento e bronquiectasias de tracao( 4=13 por cento)cavitacoes podem ocorrer por necrose(9=30 por cento) 3.Via linfatica com espessamento intersticial axial na zona medular com distorcao(25=83,3 por cento)4.Doenca progressiva com componente fibrotico e insuflacao(4=13 por cento).Conclusoes:As lesoes podem predominar em uma das duas regioes pulmonares.Temos:a padrao predominando lesoes parenquimatosas;padra predominando lesoes interticiais axiais;padrao predominando lesoes escavadas;e padrao combinado das lesoes

The neurogenesis of the callosal population of cortical cells in hamsters

The neurogenesis of the callosal subpopulation of cortical cells was determined in hamsters by associating incorporation of [3H]- thymidine injected on different embryonic days with horseradish peroxidase retrograde labelling in adulthood. Despite the great radial dispersion of migratory destinations of neurons born simultaneously, it was found that callosal birthdates in cortical area 6 extend from day E13 to day E15, a period that corresponds to the neurogenesis of layers III-V, where most callosal neurons come to be located in adults