Ultrastructural pathology of human peritumoural oedematous cerebellar cortex.

Cerebellar cortical biopsies of the peritumoural region of seven patients with cerebellar haemangioma, mesencephalic meningioma, cerebellopontine astrocytoma, cerebellopontine meningioma, and medulloblastoma of cerebellar vermis were examined by means of conventional transmission electron microscopy. Granule cells showed oedematous cytoplasm and mitochondria. Swollen Golgi cells exhibited lipofuscin granules and intranuclear inclusions. Both neuron cell types displayed swollen dendritic digits synapsing with afferent mossy fibre endings. Degenerated myelinated axons corresponding to afferent mossy and climbing fibres and efferent Purkinje cell axons were observed at the granular layer. Dense and clear ischaemic Purkinje cells established degenerated synapses with swollen parallel fibre synaptic varicosities. Degenerated Purkinje cell recurrent axonal collaterals were found at the molecular layer. Swollen and clear Bergmann glial cell cytoplasm was observed closely applied to the oedematous clear and dark Purkinje cell body, dendritic trunk, secondary and tertiary dendritic branches. Swollen climbing fibre endings featured by numerous microtubules and neurofilaments, and a decreased number of synaptic vesicles were observed making degenerated axo-spinodendritic synapses with clear and swollen dendritic spines from Purkinje, Golgi, basket and stellate cell dendrites. Swollen stellate neurons showed oedematous mitochondria. Lipofuscin-rich astrocytes and reactive phagocytic astrocytes were observed. The latter appeared engulfing haematogenous proteinaceous oedema fluid. All cerebellar neurons showed stress endoplasmic reticulum dysfunction featured by focal dilated cisterns and detachment of associated ribosomes. Myelin sheath degeneration was related with oligodendrocyte degenerating hydropic changes. The peritumoural ischaemic cerebellar nerve and glial cell abnormalities were related with neurobehavioral changes, tremor, nystagmus, dismetry and gait disturbance observed in the patients examined. The ultrastructural pathological changes were correlated with the biochemical cascade induced by vasogenic and cytotoxic oedema, altered calcium homeostasis, increased glutamate excitotoxicity, oxidative stress and DNA damage.

Confocal laser scanning microscopy and immunohistochemistry of cerebellar Lugaro cells

The present paper shows by means of confocal laser scanning microscopy the immunoreactivity of rat cerebellar Lugaro cells for calbindin, synapsin-I, PSD-95, GluR1, CaMKII alpha, and N-cadherin. Lugaro cells were easily characterized by their location beneath Purkinje cells. Calbindin revealed immunoreactivity in the cell body, and the axonal and dendritic processes. Synapsin-I labelled the presynaptic endings on Lugaro cells. Synapsin-I and PSD-95 immunoreactivity demonstrated the localization of presynaptic and postsynaptic endings surrounding cell soma, corresponding to afferent extrinsic and intrinsic cerebellar fibers. GluR1 immunoreactivity of the soma and cell processes indicates that Lugaro cells have functional ionotropic glutamate receptors that regulate calcium levels. CaMKII alpha immunoreactivity of L ugaro cell soma and processes suggest its participation as a molecular switch for long-term information storage, and serving as a molecular basis of long-term synaptic memory. N-cadherin immunoreactivity was correlated with somato-somatic and somato-dendritic junctions between Lugaro cells and their synaptic connections.

Confocal laser scanning microscopy and immunohistochemistry of cerebellar Lugaro cells

The present paper shows by means of confocal laser scanning microscopy the immunoreactivity of rat cerebellar Lugaro cells for calbindin, synapsin-I, PSD-95, GluR1, CaMKII alpha, and N-cadherin. Lugaro cells were easily characterized by their location beneath Purkinje cells. Calbindin revealed immunoreactivity in the cell body, and the axonal and dendritic processes. Synapsin-I labelled the presynaptic endings on Lugaro cells. Synapsin-I and PSD-95 immunoreactivity demonstrated the localization of presynaptic and postsynaptic endings surrounding cell soma, corresponding to afferent extrinsic and intrinsic cerebellar fibers. GluR1 immunoreactivity of the soma and cell processes indicates that Lugaro cells have functional ionotropic glutamate receptors that regulate calcium levels. CaMKII alpha immunoreactivity of L ugaro cell soma and processes suggest its participation as a molecular switch for long-term information storage, and serving as a molecular basis of long-term synaptic memory. N-cadherin immunoreactivity was correlated with somato-somatic and somato-dendritic junctions between Lugaro cells and their synaptic connections.(AU)

[Ultrastructural features of the synaptic plasticity in peritumoral cerebral oedema in humans]. / Aspectos ultraestructurales de la plasticidad sináptica en el edema cerebral peritumoral en humanos.

AIM: To provide an ultrastructural characterisation of the synaptic plasticity phenomena in peritumoral brain tissue in humans. PATIENTS AND METHODS: Sixteen peritumoral tissue biopsy samples were processed using conventional transmission electron microscope techniques. Clinical data and post-surgical follow-up were reviewed and analysed. RESULTS: In the peritumoral brain tissue there was a predominance of cellular or oncotic cerebral oedema. A large number of synapses were seen to be perforated with both convex and, although less frequently, irregular curvatures. Generally, the presynaptic terminals had an oedematous appearance, with oedematous mitochondria with cristolysis and electron-dense deposits in the mitochondrial matrix. The presynaptic terminals showed numerous synaptic vesicles of different sizes and which were sometimes arranged in small accumulations. Observations also confirmed the presence of endocytosis vesicles, which suggest high neurotransmitter reuptake. Some presynaptic terminals displayed degenerative changes. The postsynaptic terminals were seen to be oedematous and the dendritic spines displayed different shapes and spiny processes that were degenerated to varying degrees. Perisynaptic astrocytic prolongations were seen to be oedematous, with a variable number of glycogen granules. We propose a possible sequence of structural changes in the process of forming perforated synapses in peritumoral brain tissue. CONCLUSIONS: The ultrastructural findings observed in the synapses and their microenvironment can be considered to be significant with respect to the clinical manifestations and the sequelae in the patients who were studied. Moreover, they are linked to functional alterations in injured tissue, degenerative changes and neuronal death.

Aspectos ultraestructurales de la plasticidad sináptica en el edema cerebral peritumoral en humanos / Ultrastructural features of the synaptic plasticity in peritumoral cerebral oedema in humans

Caracterizar ultraestructuralmente los fenómenos de plasticidad sináptica en el tejido cerebral peritumoralhumano. Pacientes y métodos. Se procesaron 16 biopsias de tejido peritumoral mediante las técnicas convencionales para microscopía electrónica de transmisión. Se revisaron y analizaron los datos clínicos y el seguimiento posquirúrgico. Resultados.En el tejido cerebral peritumoral predominó el edema cerebral del tipo celular u oncótico. Se observaron múltiples sinapsis perforadas con curvaturas convexas y, en menor frecuencia, con curvaturas irregulares. Generalmente, los terminales presinápticospresentaron aspecto edematoso, con mitocondrias edematosas con cristolisis y matriz mitocondrial electrón densa.Los terminales presinápticos mostraron numerosas vesículas sinápticas de diferentes tamaños y ocasionalmente dispuestas en pequeños acúmulos. Se evidenció la presencia de vesículas de endocitosis que sugieren una alta recaptación de neurotransmisores.Algunos terminales presinápticos mostraron cambios degenerativos. Los terminales postsinápticos se observaron edematosos y las espinas dendríticas mostraron diferentes formas y aparatos espinosos degenerados en grado variable. Las prolongacionesastrocitarias perisinápticas se observaron edematosas, con cantidad variable de gránulos de glucógeno. Se propone una posible secuencia de cambios estructurales en el proceso de formación de sinapsis perforadas en el tejido cerebral peritumoral.Conclusiones. Los hallazgos ultraestructurales observados en las sinapsis y su microambiente pueden considerarse relevantes en relación con las manifestaciones clínicas y las secuelas de los pacientes estudiados, y se vinculan con alteracionesfuncionales del tejido lesionado, cambios degenerativos y muerte neuronal

To provide an ultrastructural characterisation of the synaptic plasticity phenomena in peritumoral brain tissuein humans. Patients and methods. Sixteen peritumoral tissue biopsy samples were processed using conventional transmission electron microscope techniques. Clinical data and post-surgical follow-up were reviewed and analysed. Results. In the peritumoralbrain tissue there was a predominance of cellular or oncotic cerebral oedema. A large number of synapses were seen to be perforated with both convex and, although less frequently, irregular curvatures. Generally, the presynaptic terminals had an oedematous appearance, with oedematous mitochondria with cristolysis and electron-dense deposits in the mitochondrialmatrix. The presynaptic terminals showed numerous synaptic vesicles of different sizes and which were sometimes arranged in small accumulations. Observations also confirmed the presence of endocytosis vesicles, which suggest high neurotransmitterreuptake. Some presynaptic terminals displayed degenerative changes. The postsynaptic terminals were seen to be oedematous and the dendritic spines displayed different shapes and spiny processes that were degenerated to varying degrees. Perisynapticastrocytic prolongations were seen to be oedematous, with a variable number of glycogen granules. We propose a possible sequence of structural changes in the process of forming perforated synapses in peritumoral brain tissue. Conclusions. The ultrastructural findings observed in the synapses and their microenvironment can be considered to be significant with respectto the clinical manifestations and the sequelae in the patients who were studied. Moreover, they are linked to functional alterations in injured tissue, degenerative changes and neuronal death

Nerve cell death types in the edematous human cerebral cortex.

Cortical biopsies of 18 patients with clinical diagnosis of congenital hydrocephalus, brain trauma, and vascular anomaly were examined with the transmission electron microscope to study the distinct and overlapped morphological cell types of nerve cell death in the human edematous cerebral cortex. The nerve cells showed lobulated and shrunken nucleus, irregular enlargement and fragmentation of perinuclear cistern, with areas of apparently intact nuclear pore complexes alternating with regions of nuclear pore complex disassembly. The nucleolus appears unaltered in moderate edema and with distorted nucleolar subcompartments in severe edema. Most nonpyramidal nerve cells, astrocytes and oligodendrocytes underwent an oncotic-apoptotic-necrotic continuum featured by swollen nucleoplasm, cytoplasm, and cell organelles, chromatin condensation and marginalization, and formation of apoptotic bodies. In a lesser proportion other nonpyramidal nerve cells, astrocytes and oligodendrocytes only showed apoptosis or oncosis. Autophagic cell death characterized by presence of autophagic vacuoles of lysosomal origin was rarely seen. The above findings suggest that different mechanisms of nerve cell death occur in the human edematous cerebral cortex related with brain trauma, congenital hydrocephalus, vascular anomaly, and their anoxic-ischemic conditions. An oncotic-apoptotic continuum process leading to necrosis predominates in human cerebral cortex nerve cell populations. The nerve cell death is discussed in relation with the severity of brain edema, anoxic-ischemic conditions of brain parenchyma, oxidative stress, glutamate excitotoxicity, calcium overload, and caspase dependent and independent mechanisms.

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.

Ultrastructural pathology of neuronal membranes in the oedematous human cerebral cortex.

Surgical biopsies of frontal, parietal and temporal regions of thirty two patients with clinical diagnosis of congenital hydrocephalus, brain trauma, tumours, and vascular anomalies were examined with the transmission electron microscope. The main goal was to study the submicroscopic alterations of somatodendritic, axonal, and synaptic plasma membranes, cytomembranes, and the cytoskeleton. In both, moderate and severe oedema, fragmentation of plasma membrane, enlargement and focal necrosis of rough endoplasmic cisterns and nuclear envelope, detachment of membrane-bound ribosomes and reduction of polysome were observed. The degenerated myelinated axons exhibited discontinuities of the axolemma, disorganisation of multiple myelin lamellae, myelin sheath vacuolization, and formation of myelin ovoids. In severe oedema, synaptic disassembly was frequently found characterized by separate pre- and postsynaptic endings and loss of perisynaptic glial ensheathment. Fragmented and intact microtubules and actin-like filaments also were distinguished. The alterations of plasma membranes and cytomembranes are related with the anoxic-ischaemic conditions of brain parenchyma. The role of free radical and lipid peroxidation, disturbed energy metabolism, altered metabolic cascades, excitotoxicity, protein aggregation, and presence of extracellular oedema fluid is discussed in relation with the derangement of neuronal membranes.

Transmission electron microscopy of cortical dendritic spines in the human oedematous cerebral cortex.

The cortical biopsies of 31 patients with clinical diagnosis of congenital hydrocephalus, vascular anomalies, brain tumours and brain trauma were examined with the transmission electron microscope. A variety of swollen spine shapes were found: mushroom shaped, filopodic, lanceolated spines, and megaspines. The spines appeared axonless or making asymmetric synaptic contacts with swollen presynaptic axons. They exhibited a disrupted actin-like network, dilated endoplasmic reticulum profiles, oedematous clear or dense mitochondria, and clusters of free ribosomes. Some spines contained a hypertrophic cytoskeleton. The spine apparatus appeared generally swollen with clear and dilated cisterns. In severe brain trauma and tumours some spine apparatus appeared disorganised or atrophic. In complicated brain trauma with subdural haematoma or hygroma some degenerated spines displayed a high electron density. The ultrastructural findings suggest that alterations of the spines are responsible for the neurological symptoms exhibited by some patients, which imply a disturbance of cortical nerve circuits. The presence of axonless spines is symptomatic of a loss of nerve connectivity, and are expected to have a significant input on neurological and mental functions.

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.

Nerve cell nuclear and nucleolar abnormalities in the human oedematous cerebral cortex. An electron microscopic study using cortical biopsies.

Cerebral cortical biopsies of 17 patients with clinical diagnosis of congenital hydrocephalus, complicated brain trauma, cerebellar syndrome and vascular anomaly were examined with the transmission electron microscope to study the nuclear and nucleolar abnormalities induced by moderate and severe brain oedema, and the associated anoxic-ischemic conditions of brain tissue. In infant patients with congenital hydrocephalus and Arnold-Chiari malformation two different structural patterns of immature chromatin organization were found: the clear type characterized by a clear granular and fibrillar structure of euchromatin, scarce heterochromatin masses and few perichromatin granules, and a dense granular and fibrillar euchromatin with abundant and scattered heterochromatin masses, and increased number of perichromatin granules. The lobulated nuclei exhibited an irregularly dilated and fragmented perinuclear cistern, and areas of apparently intact nuclear pore complexes alternating with regions of nuclear pore complex disassembly. In moderate traumatic brain injuries some nucleoli exhibit apparent intact nucleolar substructures, and in severe brain oedema some nucleoli appeared shrunken and irregularly outlined with one or two fibrillar centers, and others were disintegrated. The nuclear and nucleolar morphological alterations are discussed in relation with oxidative stress, peroxidative damage, hemoglobin-induced cytotoxicity, calcium overload, glutamate excitotoxicity, and caspase activation.

Lysosome abnormalities and lipofucsin content of nerve cells of oedematous human cerebral cortex.

Lysosome alterations and lipofucsin content of nerve cells, capillary endothelial cells and pericytes were examined in the anoxic-ischaemic brain parenchyma of thirty two patients with congenital hydrocephalus, complicated brain traumatic injuries, brain tumours and vascular anomalies. Cortical biopsies of frontal, parietal and temporal cortex were processed for transmission electron microscopy. In oedematous non pyramidal and pyramidal nerve cells, lysosomes showed fragmentation of their limiting membranes and an associated dense granulation. Areas of cytoplasmic focal necrosis were observed surrounding the lysosomes. Lipofucsin granules were also observed in neonate and infant patients with congenital hydrocephalus, suggesting that lipofucsin formation is a life span process. Lysosomes coexisting with an increased amount of lipofucsin granules were observed in young and adult patients with brain trauma, tumours and vascular anomalies. Phagocytic astrocytes and activated oligodendroglial cells showed the overall spectrum of an altered endosomal/lysosomal system. Lipofucsin granules and multivesicular bodies also were distinguished in endothelial and pericyte cells. The role of released and activated lysosomal enzymes is discussed in relation with the cytoplasmatic focal necrosis of nerve cells and the genesis of moderate and severe oedema.

Traumatic axolemmal and cytoskeletal derangement in myelinated axons of human oedematous cerebral cortex and loss of consciousness. An electron microscopic study using cortical biopsies.

Cortical biopsies of 7 patients with clinical diagnosis of severe head trauma and complicated brain trauma with subdural and epidural hematoma, and loss of consciousness were examined with the transmission electron microscope to study axolemmal and cytoskeletal damage in myelinated axons. Granular disintegration of microtubules and misaligned and fragmented neurofilaments, and fragmentation of axolemmal membrane were observed in most patients studied. In some cases a differential response characterized by increased number of neurofilaments and decreased number or disappearance of microtubules was found. In few cases apparently intact microtubules coexisting with fragmented ones were found. These findings are discussed in relation with traumatic brain edema and associated anoxic-ischemic conditions, the Hameroff-Penrose hypothesis relating microtubules and consciousness, and the existing and contemporary knowledge on neural correlates of consciousness.

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.

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.

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.

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.

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.

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.

[Imbalance of plasma amino acids in patients with autism and subjects with attention deficit/hyperactivity disorder]. / Desequilibrio de aminoácidos plasmáticos en pacientes autistas y en sujetos con trastorno de déficit de atención o hiperactividad.

INTRODUCTION: Plasma and brain amino acids are influenced by dietary intake. Alterations of plasma amino acid concentrations have been reported in neuropsychiatric disorders. OBJECTIVE: To analyse the plasma amino acid values in subject diagnosed with autism, with attention deficit/hyperactivity disorder (ADHD), and healthy subjects as controls. PATIENTS AND METHODS: Forty subjects affected by autism, 11 with ADHD and 41 healthy subjects (age range 3 18 years old) were included in this study. Peripheral venous blood was obtained in fasting condition, collected in EDTA tubes and centrifuged. Plasma was de proteinised with sulfosalicylic acid. Amino acids were analysed by ion exchange liquid chromatography with an LKB amino acid analyser with sodium citrate elution system and ninhydrin reaction. Results were expressed as mmol/L. RESULTS AND CONCLUSIONS: In both disorders a diminution of phenylalanine and glutamine plasma concentrations was observed beside an increase of glycine. Lysine appeared increased only in autistic subjects. These alterations produce an imbalance with the rest of plasma amino acids competing at the brain blood barrier by the same transport system thus causing alterations in the metabolism and/or transport of amino acids to the brain, altering CNS functions. The phenylalanine decreasing, beside glycine increasing appear to support the hypothesis of a disorder in the inhibitory neurotransmission system, especially in ADHD. The diminution of phenylalanine and the increasing of lysine in autism are suggestive that these two amino acids are metabolically related.