Estudio morfométrico comparativo de la corteza cerebelosa humana en dos grupos etarios / Comparative morphometric study of human cerebellar cortex in two age groups

Histológicamente la corteza del cerebelo humano adulto presenta tres capas constitutivas; la capa molecular, la hilera de los cuerpos de las células de Purkinje y la capa granulosa interna. La sustancia cortical del cerebelo de los embriones de mamífero, así como la de los jóvenes, muestran una capa granular externa. Nuestro objetivo es documentar las diferencias morfológicas entre las capas de la corteza cerebelosa adulta y joven. Se realizaron estudios morfométricos microscópicos en 20 cerebelos de autopsias. Los casos se dividieron en dos grupos, adultos y niños menores de 1 año. Se realizaron cortes en parafina, coloreados con hematoxilina y eosina. La corteza del cerebelo adulto presentó diferencias morfológicas con la de los recién nacidos. En el cerebelo adulto presenta tres capas constitutivas, mientras que en el recién nacido presenta una cuarta capa, la granulosa externa...

Histologically, the adult human cerebellar cortex has three constituent layers, the molecular layer, the row of bodies of Purkinje cells and internal granular layer. The cortex of the cerebellum of mammalian embryos, as well as youth, show external granular layer. Our goal is to document morphological differences between the layers of the cerebellar cortex adult and young. Microscopic morphometric studies were performed in 20 cerebellum autopsied. The cases were divided into two groups, adults and children under 1 year. Paraffin sections were performed, stained with hematoxylin and eosin. The cortex of adult cerebellum showed morphological differences of the newborn. In the adult cerebellum has three constituent layers, whereas in the newborn has a fourth layer, the external granular...

Correlative microscopy of Purkinje cells

The Purkinje cell and their synaptic contacts have been described using (1) light microsocopy, (2) transmission and scanning electron microscopy, and freeze etching technique, (3) conventional and field emission scanning electron microscopy and cryofracture methods, (4) confocal laser scanning microscopy using intravital stain FM64, and (5) immunocytochemical techniques for Synapsin-I, PSD9-5, GluR1 subunit of AMPA receptors, N-cadherin, and CamKII alpha. The outer surface and inner content of plasma membrane, cell organelles, cytoskeleton, nucleus, dendritic and axonal processes have been exposed and analyzed in a three-dimensional view. The intramembrane morphology, in bi- and three-dimensional views, and immunocytochemical labeling of synaptic contacts with parallel and climbing fibers, basket and stellate cell axons have been characterized. Freeze etching technique, field emission scanning microscopy and cryofracture methods, and GluR1 immunohistochemistry showed the morphology and localization of postsynaptic receptors. Purkinje cell shows N-cadherin and CamKII alpha immunoreactivity. The correlative microscopy approach provides a deeper understanding of structure and function of the Purkinje cell, a new three-dimensional outer and inner vision, a more detailed study of afferent and intrinsic synaptic junctions, and of intracortical circuits.

Effects of prenatal exposure to static magnetic field on the development of the cerebellar purkinje cells

Many studies were performed to evaluate the effects of static magnetic fields [SMFs] on the processes of proliferation and migration of cerebellar cells to their final postnatal destinations. Purkinje cell [PC] as one of the most critical station for all afferent input to the cerebellum as well as the major output from the cerebellum either direct or indirect through the other cerebellar neurons and development of Purkinje cells depends on their postnatal migration which is vulnerable to any micro-environmental insult. To evaluate the light and electron microscopic changes occurred to the cerebellar PCs of the pups after prenatal exposure to SMF [20 mT]. Prenatal exposure showed a significant decrease in the number of PCs as compared with that number in the control group throughout the time of study with appearance of some pathological changes at the cellular level obvious from the postnatal day 4 till the end of the study, as there were many apoptotic cells, few cells degenerated with astrocytosis near the Purkinje cells with large cytoplasmic vacuoles inside the cells and many cells became atrophied cells. The prenatal exposure to static magnetic field led to decrease ability of the proliferation, delay in the development and appearance of some degenerative changes in different stages of the postnatal development of the cerebellar cortex and these changes persisted till the adult life

Further observations on cerebellar climbing fibers. A study by means of light microscopy, confocal laser scanning microscopy and scanning and transmission electron microscopy

The intracortical pathways of climbing fibers were traced in several vertebrate cerebella using light microscopy, confocal laser scanning microscopy, scanning and transmission electron microscopy. They were identified as fine fibers up to 1(micron thick, with a characteristic crossing-over bifurcation pattern. Climbing fiber collaterals were tridimensionally visualized forming thin climbing fiber glomeruli in the granular layer. Confocal laser scanning microscopy revealed three types of collateral processes at the interface between granular and Purkinje cell layers. Scanning electron microscopy showed climbing fiber retrograde collaterals in the molecular layer. Asymmetric synaptic contacts of climbing fibers with Purkinje dendritic spines and stellate neuron dendrites were characterized by transmission electron microscopy. Correlative microscopy allowed us to obtain the basic three-dimensional morphological features of climbing fibers in several vertebrates and to show with more accuracy a higher degree of lateral collateralization of these fibers within the cerebellar cortex. The correlative microscopy approach provides new views in the cerebellar cortex information processing.

Utility of silver-colloidal staining method in the diagnosis of medulloblastoma.

Histopathological features of medulloblastomas are usually distinctive. However in rare instances, a distinction between the neoplastic cells of medulloblastoma and the neurones in the cerebellar internal granular layer becomes difficult at light microscopic level. In order to distinguish presence of argyrophilic Nucleolar Organizer Regions (Ag-NORs) was analysed in the paraffin sections of medulloblastoma as well as in the cerebellar internal granular layer. The neoplastic cells in medulloblastoma contained a mean 4.78 Ag-NOR per nucleus while the neurones in cerebellar internal granular layer contained a mean Ag-NOR 0.90 +/- 0.12 per nucleus. Compound Ag-NORs were present in the cells of medulloblastoma while they were absent in the neurones of cerebellar internal granular layer. The results of this study indicate that Ag-NOR technique may be useful in an uncommon situation, where a histopathological distinction between cells of medulloblastoma and neurones in the cerebellar internal granular layer becomes difficult.