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O J Castejón

Publications and source records attributed to O J Castejón.

At least 19 recordsLinked to original sources
PubMed2005

The inflammatory reaction in human traumatic oedematous cerebral cortex.

The inflammatory reaction surrounding hemorrhagic and perihematomal brain parenchyma has been studied by means of light and transmission electron microscopy in 12 patients with severe traumatic head injuries complicated with subdural or extradural hematoma or hygroma. Perivascular cells, ameboid phagocytic microglial cells, and infiltrated macrophage/monocyte system were observed surrounding perivascular and intraparenchymal hemorrhagic foci. They showed phagocytic activity of degenerated nerve cell processes, and organized proteinaceous edema fluid present in the enlarged extracellular space. Endocytosis by means of clathrin coated vesicles also was observed. Facultative and professional phagocytes exhibited a full repertoire of lysosomes, phagosomes containing nerve cell debris, lipid droplets, and lipofucsin granules. Phagocytic pericytes remaining within the capillary basement membrane were also observed around perivascular hemorrhages. The inflammatory reaction was examined in young and old patients with an evolution time of brain injury ranging from 1 day to 2 years. The inflammatory process developed according to the intensity of traumatic insult, patient age, associated hematoma or hygroma, severity of vasogenic and cytotoxic oedema, and anoxic-ischemic conditions of brain parenchyma.

Adolescent↗
PubMed2004

Correlative microscopy of Purkinje dendritic spines: a field emission scanning and transmission electron microscopic study.

Purkinje dendritic spines (Pds) of mouse cerebellar cortex were examined by field emission scanning electron microscopy (FESEM) and by transmission electron microscopy (TEM) using ultrathin sections and freeze-etching replicas, to study their three-dimensional features and intramembrane morphology. FESEM showed unattached mushroom-type, elongated and lanceolate Pds separated by 100-500 nm on the dendritic shaft surface. High resolution FESEM showed 25-50 nm globular subunits at the spine postsynaptic density corresponding to the localization of postsynaptic proteins and/or postsynaptic receptors. TEM images of ultrathin sections showed gem-like, mushroom-shaped, lanceolate and neckless or stubby spines. Freeze etching replicas exposed postsynaptic intramembrane particles that can be correlated with the globular subunits observed at high resolution FESEM. Parallel and climbing fiber endings were observed making asymmetric synaptic contacts with the Pds heads. Simultaneous contacts with the necks and heads were also found. The variety of Pds shapes were interpreted as spine conformational changes related with spine dynamic, and spine plasticity.

Animals↗
PubMed2003

Synaptic plasticity in the oedematous human cerebral cortex.

Synaptic plastic changes are fundamental events which occur spontaneously during development, maturity and aging processes or can be induced by injury or trauma. To examine lesion-induced synaptic plasticity, cortical biopsies were taken from the frontal, parietal, temporal and occipital cortex of living patients during neurosurgical treatment of brain trauma, brain tumours and vascular malformations, and processed for transmission electron microscopy. Enlargement of both pre- and postsynaptic endings, irregularly shaped, lobulated, stellate and bifurcated presynaptic endings and conformational changes of dendritic spines were observed. Numerous flat, curved and invaginated axodendritic and axospinous asymmetric synapses were distinguished and a smaller proportion of axodendritic and axosomatic symmetric synapses. Activated or sensitized synapses showed numerous frontline spheroid synaptic vesicles, prominent dense presynaptic dense projections and increased length of synaptic membrane complex. Perforated synapses, multiple synapses and serial synapses were also found evincing synaptic splitting and formation of new synaptic connections. The overall images suggest increased number of excitatory circuits, which were correlated with the tonico-clonic convulsion or post-traumatic seizures observed in some patients. Numerous coated vesicles were observed in pre- and postsynaptic structures. Increased number of polyribosomes were found in the dendritic shafts. The dilated spine apparatus, the coated vesicles and the increased number of polyribosomes seem to represent a system for synthesis, transport and storage of synaptic proteins for the formation of new synapses. Coexisting synaptic plasticity and synaptic degeneration were observed in the patients under study. Dendritic and astrocyte synapse-like junctions were also characterized.

Adolescent↗
PubMed2003

Intranuclear filamentous inclusion in human oedematous cerebellar Golgi cells.

The presence of intranuclear filamentous inclusions in cerebellar Golgi cells is reported in three patients with cerebellar tumours. Samples of cerebellar cortex were processed for conventional transmission electron microscopy. Cerebellar biopsies were performed according to the basic principles of Helsinki declaration. Intranuclear inclusions observed in oedematous Golgi cells, appeared as straight rodlets up to 3 microm in length and up to 0.4 microm in width, characterized by a periodic or crystalloid structure formed by dense bands, 9.2 nm thick separated by clear spaces, 5.4 nm in width. These structures are considered abnormal protein aggregates apparently induced by excitotoxicity, oxidative stress and impaired energy metabolism.

Cerebellar Neoplasms↗
PubMed2003

Morphological changes of dendrites in the human edematous cerebral cortex. A transmission electron microscopic study.

The structural pathology of dendritic processes has been examined in 38 patients with clinical diagnosis of brain trauma, brain tumours and congenital malformations. Cortical biopsies of frontal, parietal, temporal and occipital cortex were conventionally processed for transmission electron microscopy. Isolated ultrathin sections and montages of electron micrographs were used to trace the intracortical dendritic course. Swollen and beaded dendrites were observed in all cases examined, which exhibited fragmentation of limiting plasma membrane and cytoskeletal structures. The swollen dendrites showed vacuolization, dense residual bodies, enlarged rough and smooth endoplasmic reticulum, edematous clear and dark mitochondria, a decreased synaptic density of shaft synapses, edematous and dystrophic changes of spine apparatus and a partial loss of dendritic spines. A wide variety of dendritic spine shapes were observed: mushroom-type, stubby, gem-like filiform spine, and megaspine, considered as spine dysgenesis in the congenital malformations and spine pathology and spine plasticity in brain traumatic injuries and brain tumours. The multifactorial processes associated with brain edema and brain ischemia, such as calcium overload, activation of calcium-dependent proteolytic enzymes, protein aggregation, glutamate-induced neurotoxicity, release of lysosomal enzymes, deficit of ATP, stress oxidative and lipid peroxidation have been considered in relation with the pathological dendritic changes. Dendrotoxicity due to brain edema and brain ischemia seems to be the fundamental pathogenetic mechanism.

Anterior Cerebral Artery↗
PubMed2002

A light and electron microscopic study of oedematous human cerebral cortex in two patients with post-traumatic seizures.

PRIMARY OBJECTIVE: Brain cortical biopsies of two patients with clinical diagnosis of complicated brain trauma who had seizures, were studied by means of light and electron microscopes in order to correlate structural alterations with seizure activity. METHODS AND PROCEDURES: Biopsy samples of left frontal cortex and right parietal cortex were processed by current techniques for light and transmission electron microscopy. RESULTS: The tissue showed severe vasogenic oedema with perivascular and intraparenchymatous haemorrhages. At the capillary wall, increased vesicular and vacuolar transendothelial transport, open endothelial junctions, thickened basement membrane and swollen perivascular astrocytic end-feet were observed. Some pyramidal and non-pyramidal nerve cells appeared dense and shrunken and others exhibited marked intraneuronal enlargement of membrane compartment. The myelinated axons displayed signs of degeneration and a process of axonal sprouting. Numerous swollen asymmetrical axo-dendritic synaptic contacts were observed in the neuropil, which exhibited mostly closely aggregated spheroidal synaptic vesicles toward the presynaptic membrane and numerous exocytotic vesicles sites. The perisynaptic astrocytic ensheathment appeared retracted or absent, whereas the extracellular space appeared notably dilated. Synaptic disassembly was also observed. CONCLUSION: The findings demonstrate, in two patients with post-traumatic seizure activity, brain barrier dysfunction, vasogenic oedema, anoxic-ischaemic neurons, axonal sprouting, numerous altered excitatory synapses and synaptic disassembly. Some considerations on clinical and research applications are discussed.

Adolescent↗
PubMed2002

Correlative microscopy of cerebellar Bergmann glial cells.

Double fluorescent labelling of rat cerebellar cortex using antibody to glial fibrillary acidic protein (GFAP) and Alexa fluor conjugates for secondary detection for confocal laser scanning microscope (CLSM), field emission scanning electron microscopy (FESEM) of Rhesus monkey cerebellar cortex, ultrathin sectioning and freeze-etching replica method for transmission electron microscopy of mouse cerebellar cortex have been examined in an attempt to obtain a new and more accurate view of three-dimensional image of Bergmann glial cells (BGC) and their topographic relations in the molecular layer. Intense immunopositive GFAP green staining was observed in the BGC and glial limiting layer. Secondary antibody conjugated with Alexa fluor 488 and Alexa fluor 668-1B4 stained in red capillary endothelial cells and microglial cells. BGC morphology revealed the existence of several cell types or subpopulations of BGC. Bergmann glial fibers, in palisade arrangement, branch and rebranch forming a complex glial network in the molecular layer. Field emission SEM and freeze-fracture SEM method show the SE-I image of high mass dense Bergmann glial cytoplasm ensheathing like a veil the Purkinje cell (PC) soma and dendritric arborization. Bergmann glial fibers appeared completely surrounding individual parallel fibers or parallel fiber bundles, terminal climbing fiber collaterals, basket and stellate cells and capillaries. Freeze-etching direct replicas showed the typical orthogonal arrangement of intramembrane particles, corresponding to the large repertoire of BGC receptors. The study reveals three-dimensional Bergmann glial cells heterogeneity and the complex network formed by Bergmann glial cells in the molecular layer.

Animals↗
PubMed2002

Electron microscopy of umbilical cord endothelial cells in preeclampsia.

We have studied by means of transmission electron microscopy the umbilical cord endothelial cells in 11 preeclamptic women. Endothelial cells exhibited oval, round, elongated, flattened, triangular or polygonal shapes. The nuclei displayed shallow and deep invaginations of nuclear envelope. The endoplasmic reticulum appeared highly dilated and vacuolated. The swollen mitochondria showed cristae fragmentation. Areas of focal necrosis were appreciated throughout the cytoplasm. A marked enlargement of subendothelial space and the presence of an electron dense granular material were also found. The findings reveal activation and injury of endothelial cells and disruption of endothelial cell layer.

Adult↗
PubMed2001

Confocal laser scanning, conventional scanning and transmission electron microscopy of vertebrate cerebellar granule cells.

Confocal laser scanning microscopy of hamster cerebellar granular layer showed in montages of z-series the presence of small, medium and large granule cells. A granule cell Golgi cell ratio of 50/4 was observed surrounding glomerular regions. Field emission high resolution scanning electron microscopy of mouse cerebellar granular and molecular layers showed SE-I images of the outer and inner surfaces of nuclear and cytoplasmic compartments of chromium coated granule cells and the axo-spinodendritic synapses of parallel fibers with Purkinje cell dendrites. Conventional scanning electron microscopy of teleost fish cerebellar cortex showed three dimensional morphology of granule cell soma and processes and the synaptic relationship with mossy and climbing fibers, Golgi cell axonal ramifications and dendrites of stellate neurons, by means of SE-II and SE-III signal image mode, in sagittally and transversally cryofractured cerebellar cortex. SE-II images of the non-synaptic segments and synaptic varicosities of parallel fiber outer surface were characterized in the molecular layer. Ultrathin sections of transmission electron microscopy (TEM) revealed somato-somatic, dendro-somatic and dendro-dendritic like-desmosomal and like-hemidesmosomal junctions in human cerebellar granule cells. Freeze-etching replicas of mouse cerebellar cortex displayed granule cell intramembrane morphology, cytoplasmic fractured face and the Bergman glial cell cytoplasm completely surrounding the parallel fibers in the molecular layer. The mossy fiber-granule cell dendrite synaptic relationship was observed in sagittally and transversally cryofractured cerebellar cortex and correlated with TEM images. SE-II images of the climbing fiber synaptic connections with granule cell dendrites were obtained in teleost fish cerebellar cortex. One to one axo-dendritic synaptic contacts between Golgi cell axonal ramifications and granule cell dendrites were also seen. The above findings provide new vistas for future studies dealing with intracortical circuits and information processing in the cerebellar cortex.

Animals↗
PubMed2001

Field emission scanning electron microscopy and freeze-fracture transmission electron microscopy of mouse cerebellar synaptic contacts.

Samples of albino mice were processed by the cryofracture method for scanning electron microscopy and examined with the field emission scanning electron microscope (FESEM). Freeze-etching direct replicas of mice cerebellar cortex were also studied with the transmission electron microscope (FFTEM), as a complementary technique for obtaining higher resolution, three-dimensional correlative images of cerebellar synaptic contacts. At the granular, Purkinje cells and molecular layers, the cryofracture method for FESEM selectively removed the neuroglial cell investment, facilitating the visualization of the outer and inner surfaces of cerebellar synaptic contacts. In addition, FFTEM showed the real extension of perisynaptic neuroglial investment. The outer surface of mossy fiber rosettes and their digitiform processes were seen at the granular layer, making flat and invaginated synaptic contacts with the granule cell dendrites. At the molecular layer, the longitudinal traject of parallel fibers or nonsynaptic segments and their synaptic varicosities were characterized. These latter established synaptic contacts with Purkinje dendritic spines. Fractured parallel fiber endings showed the SE-I images of clustered spheroidal synaptic vesicles and mitochondria and the surrounding cotton-like appearance of Bergmann glial cell cytoplasm. Climbing fibers showed a characteristic crossing-over bifurcation pattern in the white matter and in the three-layer structure of cerebellar cortex, formation of tendril collaterals in the granular layer, topographical relationship with Purkinje cell soma and retrograde collaterals in the molecular layer. The climbing fiber synaptic relationship with Purkinje dendritic spines was characterized, by means of FFTEM, by the presence of large synaptic endings and aggregation of intramembrane particles at the P and E faces of presynaptic endings, characteristic of excitatory synapses.

Animals↗
PubMed2000

Correlative microscopy of cerebellar Golgi cells.

The cerebellar Golgi cells of mouse, teleost fish, primate and human species have been studied by means of light and Golgi light microscopic techniques, confocal laser scanning microscopy, slicing technique, ethanol-cryofracturing and freeze-fracture methods for scanning electron microscopy and ultrathin sectioning and freeze-etching replicas for transmission electron microscopy. The Golgi cells appeared in the granular layer as polygonal, stellate, round or fusiform macroneurons surrounded by the granule cell groups. They exhibited ascending dendrites toward the molecular layer and horizontal dendrites and a short beaded axonal plexus confined to the granular layer. Scanning electron microscopy revealed their three-dimensional neuronal geometry and smooth outer surfaces. Freeze-fracture method for SEM showed the stereospatial cytoplasmic arrangement of endoplasmic reticulum, cell organelles and nuclear envelope. By means of transmission electron microscopy the asymmetric synaptic connections of Golgi cell horizontal dendrites--with mossy fiber rosettes at the cerebellar glomerulus--and of Golgi cell axons--with granule cell dendrites at the periphery of glomerular region--were identified. At the molecular layer, Golgi cell ascending dendrites exhibited short neckless spines establishing asymmetric contacts with granule cell axons or parallel fibers. Shaft asymmetric axodendritic and axospinodendritic contacts between Golgi cell dendrites and climbing fibers were also found in the molecular layer.

Animals↗
PubMed2000

Confocal, scanning and transmission electron microscopic study of cerebellar mossy fiber glomeruli.

A correlative microscopic study of vertebrate cerebellar mossy fiber glomeruli has been carried out to obtain a three-dimensional view of the multisynaptic contacts formed by afferent mossy fibers with the granule and Golgi cell dendrites and by the monosynaptic relationship of Golgi cell axonal ramifications with granule cell dendrites. Samples of mice, hamsters, teleost fishes and human species were studied by means of one of the following procedures: confocal laser scanning microscopy (CLSM), ethanol-cryofracturing technique and conventional scanning electron microscopy (CSEM) and transmission electron microscopy (TEM) by ultrathin sections and freeze-etching replicas. CLSM, by means of montages of z-series of the cerebellar granular layer, provided a new approach to explore mossy fiber trajectory and branching bifurcation pattern and the quantitative relationship between mossy fibers and granule cell dendrites. CSEM and freeze-fracture method for SEM offered a more detailed in-depth, higher resolution image of outer and inner surface organization of mossy fiber glomeruli. TEM, either by ultrathin sections or freeze-etching replicas, was used as complementary technique for proper orientation, comparative purposes and rational identification of pre- and postsynaptic structures. Freeze-etching replicas showed in addition the real extent of glial cell cytoplasm encapsulating the synaptic glomeruli. The integrated microscopy approach offers a new and more comprehensive view of three-dimensional morphology, organization and quantitative aspects of mossy fiber glomeruli.

Animals↗
PubMed2000

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.

Adolescent↗
PubMed1999

Astrocyte subtypes in the gray matter of injured human cerebral cortex: a transmission electron microscope study.

Astrocytic subtypes in different cortical regions of injured human cerebral cortex of 22 patients with brain trauma, vascular anomalies and brain tumours have been examined by means of light microscopy and conventional transmission electron microscopy. The cortical biopsies of frontal, parietal and temporal cortex were examined to analyse the heterogeneous astrocytic response and characterize astrocytic population subtypes. Swollen clear and dense astrocytes, glycogen rich- and glycogen-depleted astrocytes, aged or lipofucsin rich-astrocytes and reactive, dark, hypertrophic astrocytes were identified. Clear and dense astrocytes displayed bundles of glial filaments and dense inclusion bodies. Glycogen-rich astrocytes exhibited an accumulation of beta type of monogranular glycogen granules, which disappear in the glycogen-depleted astrocytes, suggesting anoxic mobilization of glycogen stores during ischemia or anoxia. Lipofucsin rich astrocytes were mainly related with ageing processes, although their presence in young patients suggests also an injured related process. Dark astrocytes with phagocytic properties were found. They exhibited bundles of glial filaments. The astrocytic response depended upon the nature of cortical insult, extent of damage, time course of pathological lesion and affected cortical region.

Adolescent↗
PubMed1999

Ultrastructural pathology of Golgi apparatus of nerve cells in human brain edema associated to brain congenital malformations, tumours and trauma.

The alterations induced by ischemia and anoxia upon smooth endoplasmic membranes are studied in 38 patients with congenital malformations, brain tumours and brain trauma. The effects of vasogenic and cytotoxic brain edema are examined in the Golgi apparatus of nerve and endothelial cells. Samples of cortical biopsies were conventionally processed for transmission electron microscopy. Cortical biopsies were performed according to the basic principles of Helsinki declaration. Slices of 2 to 5 mm were immediately fixed in the surgical room in 4% glutaraldehyde-0.1 M sodium phosphate buffer, pH 7.4 at 4 degrees C, and postfixed in 1% osmium tetroxide in similar buffer. The pathological alterations of the Golgi complex were studied in samples with moderate and severe brain edema. Moderate edema was mainly found in congenital malformations and severe edema in brain trauma and tumours. In some severely edematous neurons, observed in hydrocephalus associated to Arnold-Chiari malformation, small vesicular type Golgi complexes and atrophic ones were observed, characterized mainly by partial or total disappearance of stacked Golgi cisternae and presence of congregated vesicular profiles. In brain trauma and tumours the Golgi complex showed enlargement and fragmentation of the stacked cis- medial- and trans-Golgi cisternae and vacuolization of trans-Golgi network. In addition, an increased formation of Golgi and coated vesicles was observed in the cis- and trans-Golgi regions. Most Golgi and clathrin coated vesicles were observed throughout the cytoplasm suggesting an increased vesicular transport. In severe edema the nerve cell plasma membranes appeared fragmented, presumably due to an interference of the protein insertion process into the plasma membrane. In brain trauma, a hypertrophic Golgi complex was observed in some nerve cells and endothelial cells of cortical capillaries, with increased formation of Golgi and coated vesicles. The ischemia and anoxia associated to the vasogenic and cytotoxic brain edema induced enlargement, fragmentation and disappearance of stacked Golgi cisternae.

Adolescent↗
PubMed1998

Morphological astrocytic changes in complicated human brain trauma. A light and electron microscopic study.

The astrocytic changes and reactivity in human brain trauma complicated with subdural haematoma or hygroma have been analysed in nine patients. Cortical biopsies of frontal, temporal and parietal regions were examined with light and transmission electron microscopy. At light microscopy level oedematous clear and dense astrocytes, binucleated and multinucleated astrocytes and hypertrophic reactive astrocytes were distinguished in either moderate or severe vasogenic brain oedema. Swollen, clear and dense perineuronal astrocytes were observed compressing and indenting dark, degenerated pyramidal and non-pyramidal nerve cells. At electron microscopy level glycogen-depleted and glycogen-rich astrocytes were found in some patients. Dense and reactive hypertrophic astrocytes exhibited increased amounts of dilated smooth endoplasmic reticulum, microtubules, lipofucsin granules, gliofilaments and alpha type glycogen particles. In severe oedema the astrocytic ensheathment of synaptic contacts is lost, the perivascular astrocyte end-feet appeared dissociated from the capillary basement membrane and the interastrocytary gap junctions are disrupted. The posttraumatic neurological deficits and the neurobehavioural disorders of the patient studied are correlated with astrocyte ultrastructural changes and blood brain barrier disruption.

Adolescent↗
PubMed1998

Electron microscopic analysis of cortical biopsies in patients with traumatic brain injuries and dysfunction of neurobehavioural system.

Cortical biopsies of eight patients with craniocerebral trauma complicated with subdural or epidural hematoma were examined with the transmission electron microscope. The patients showed post-traumatic neurobehavioural disorders and moderate or severe vasogenic brain edema. The capillary wall displayed increased vacuolar and vesicular endothelial transport, basement membrane thickening and vacuolization and swollen astrocytic end-feet. Pericapillary and parenchymatous hemorrhages were also observed. The extracellular space appeared considerably enlarged with presence of proteinaceous hematogenous edema fluid and fibrinous organization. Pyramidal and non-pyramidal neurons showed intracellular edema featured by irregular enlargement of rough endoplasmic reticulum, nuclear envelope and Golgi apparatus. The myelinated axons exhibited clear or black type axoplasmic degeneration, varicose fiber swelling, myelin sheath distortion, formation of myelin ovoids and increased amount of oligodendroglial ad-axonal layer. The dendrites also showed clear or dark and beaded shape degeneration. Synaptic degeneration was characterized by swollen and shrunken pre- and postsynaptic endings, clumping, enlargement and depletion of synaptic vesicles, synaptic membrane complex disassembly and detachment of glial ensheathment. Perivascular and perineuronal astrocytes appeared remarkably swollen. Phagocytic astrocytes were also found. Oligodendrocytes displayed hydropic and reactive changes. Reactive oligodendrocytes induced myelinolysis. The brain barrier dysfunction, the vasogenic and cytotoxic edema and the subsequent neuronal and neuroglial cell reactive and degeneration processes might represent the morphological substrate responsible for the post-traumatic neurobehavioural disorders.

Adolescent↗