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.

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.

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.

[Imbalance of plasma amino acids in patients with autism and subjects with attention deficit/hyperactivity disorder]

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.

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.

[Prevalence of sub-clinical vitamin A deficiency and malnutrition in slum children in Maraicabo - Venezuela]

The present cross sectional study was carried out to estimate the prevalence of vitamin A deficiency among children by means of clinics and conjunctival impression cytology (CIC), and nutritional status by anthropometric indicators H//A, W//A, W//H. The study population included 157 children 2-6 y old, from urban and rural slums of Maracaibo, Venezuela, Conjunctival impression cytology was performed by ICEPO standard procedure. Z-score was applied to anthropometric data with reference values of NCHS-WHO. No evidence of clinical or ophthalmologic signs of vitamin A deficiency were detected. The prevalence of subclinical vitamin A deficiency, as detected by abnormal CIC, was 35.4%, being higher in rural children (48.3%). These prevalence values are higher than the criteria laid down by WHO/UNICEF to indicate a public health problem (> 20%). Mild or moderate protein-energy global malnutrition and stunting were detected in 36.1% and 44.6% of children, respectively. Abnormal CIC was indistinctly observed (approximately equal to 35%) as much in children with adequate nutrition as in malnourished ones. There was no significant difference in the distribution of the CIC results in relation to nutritional status. The findings indicate that CIC and Z-score of nutritional anthropometric data are useful to characterize the risk of vitamin A deficiency and of malnutrition in communities. Beside the implementation of an integral nutritional program which includes supplementation, food fortification and dietary diversification, improvement of socio-economic and sanitation conditions and also the educational level, with emphasis on nutritional and health education, are highly recommended.

Oligodendroglial cell damage and demyelination in infant hydrocephalus. An electron microscopic study

The hydropic changes of oligodendroglial cells have been examined by means of transmission electron microscopy in seventeen cases of human, mostly infant hydrocephalus and associated pathology. Hydropic oligodendrocytes exhibited dilated endoplasmic reticulum and nuclear envelope, edematous mitochondria, enlarged and fragmented Golgi complexes, dense bodies and nuclear chromatin homogenization. A process of nuclear pore disassembly, extrusion of nuclear heterochromatin and an apoptotic-like process were observed in some swollen oligodendrocytes. Some resting or quiescent oligodendrocytes were also observed in the edematous neuropil. Oligodendrocyte cell processes appeared atrophic, degenerated and isolated in the enlarged extracellular spaces. They did not show any association with neighbouring axons, and myelinated axons were not observed in the neuropil. These observations suggest demyelination in infant hydrocephalus.

Light microscopy, confocal laser scanning microscopy, scanning and transmission electron microscopy of cerebellar basket cells

The cerebellar basket cells of mice, hamsters, teleost fishes and human have been studied by means of Golgi light microscopy, confocal laser scanning microscopy, scanning and transmission electron microscopy. Golgi light microscopy showed ascending dendrites toward the molecular layer and descending and transverse axonal collaterals contributing to the formation of Purkinje cell pericellular basket. Confocal laser scanning microscopy provided z-series of optodigital sections of ascending basket cell dendrites and descending axonal collaterals participating in the Purkinje cell pericellular nest and the pinceaux. Scanning electronmicrographs displayed the three-dimensional relief of Purkinje pericellular nest formed by basket cell descending and transverse axonal collaterals. Transmission electron microscopy, used as a complementary technique, showed the synaptic contacts formed by basket cell axonal collaterals on Purkinje cell soma and the axosomatic contacts on basket cells by parallel and climbing fiber endings, basket cell axonal terminals and/or Purkinje cell recurrent axonal collaterals. Pre- and postsynaptic membrane specializations were mainly found in parallel fiber axosomatic contacts on basket cells, but not in the Purkinje cell pericellular basket and in other axosomatic contacts on basket cells. These latter findings have been adscribed to a phenomenon of cerebellar synaptic plasticity related with motor learning performance. The correlative microscopy approach demonstrates the potential value of these methodologies for studying the three-dimensional aspect of short intracortical circuits in the central nervous system.

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.

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.

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.

Imbalance of Individual Plasma Amino acids Relative to Valine and Taurine as Potential Markers of Childhood Malnutrition

In the present study a typical plasma amino acid profile for a defined population of healthy Venezuelan children was established and, further, the possibility was examined that deviations from such normalized amino acid patterns can be of use to warn of an impending nutritional deficiency, caused, in part, by adverse socio-economic conditions. This study comprised 152 children of both sexes ranging in age from 1 to 6 years. Classification into different socio-economic strata, ranging from impoverished to privileged, was evaluated by Graffar's method, as previously adapted by Mendez Castellano for Venezuela. The results of clinical and anthropometric examinations were used to group these children into 5 classes of nutritional sufficiency, ranging from adequate nutrition to severe undemutrition. The present data indicate that deviations in the plasma amino acid concentration profile, standardized for a defined population, can be used in combination with clinical evaluations to determine the type as well as the severity of inadequate nutrition. Abnormal ratios of several individual amino acids relative to Val and Tau may serve as early signs of (impending) undemutrition or malnutrition in children; the amino acid changes are detectable even in groups of children without any clinical signs but where sociological circumstances suggest a possibility of inadequate nutrition. Other uses for such plasma amino acid profiles may be to distinguish whether the detected amino acid abnormalities are of dietary or genetic origin, provided that the selected groups or individuals studied derive from a population with more or less the same genetic homogeneity and similar dietary customs.

[Nutritional characteristics of a cookie formulated with bovine blood plasma as a main source of protein]

The nutritional characteristics of a cookie formulated with bovine plasma as main protein source was evaluated. Bovine plasma was mixed with wheat flour, sugar or salt, condiments and vegetable oil. The mix was placed in trays and baking at 120 degrees C during 1 hour. Moisture, fat, protein, carbohydrate, metabolizable energy, ash, iron, essential amino acids, essential fatty acids, apparent digestibility, protein efficiency ratio, acceptability and tolerance of the final product were determined. Results indicated that 100 g of the cookie have 5 g of moisture, 16 g of fat, 16 g of protein, 61.4 g of carbohydrate, 408.2 Kcal of metabolizable energy, 1.59 g of ash, 1.9 mg of iron and 6.59 g of essential amino acids. Polyunsaturated fatty acids are in higher amount than saturated fatty acids. Results also indicated that 100 g of cookie provide at least 20% of the daily energy requirements, 24% of the iron and between 30 to 50% of the daily protein requirements for children at school age. Its digestibility and PER, tested in rats, were of 88.4% and 2.32 respectively. Acceptability and tolerance, both tested in children, were 97% and 100% respectively. The protein cookie could be included as a protein and energy supply in school meals.

[Zinc plasma levels in a low socioeconomic status population of children in Maracaibo, Venezuela]

The objective of the present work was to determine plasma zinc concentration in a children's population belonging to low income families in Maracaibo, Venezuela. One hundred fifty-nine children (M:75;F:84) aged 3 months to 8 years were studied by clinic, anthropometric and socio-economical parameters. Fasting peripheral venipuncture blood samples were obtained and analyzed for plasma zinc using atomic absorption spectrophotometry. Plasma zinc levels were low (< 75 micrograms/dl) in 38.36% of the children studied. In turn, 33.89% of the eutrophic group, and 41% of the malnourished group were zinc deficient. By analyzing separately the group of children in which plasma zinc levels ranged between 75-80 micrograms/dl (critical zone), it could be seen that 18.65% of eutrophic and 10% of malnourished children belonged to this group. Thus, over 50% of the total children's population studied had critical or deficient plasma zinc levels. Therefore, functional studies on nutritional status of zinc are recommended to the Venezuelan children population; in case of being evidently deficitary, it is necessary to establish immediate zinc supplementation nutritional programs; especially for children coming from low income families.

High resolution (SE-I) scanning electron microscopy features of primate cerebellar cortex

This paper provides an exploration into the outer and inner surfaces of primate cerebellar neurons using secondary electron-I (SE-I) topographic contrast. SE-I enriched, chromium coated, cryofractured cerebellum staged within the condenser/objective lens stage of SEMs, equipped with high brightness LaB6 and field emission emitter, generated quality images of intact and fractured nerve cells studied at intermediate and high magnifications. Granule and Golgi cell surfaces revealed smooth, accurately delineated profiles of the true cell surface features, which lacked the SE-III dominated brilliance of conventional gold or gold-palladium decorated images. Fractured non synaptic segments of parallel fibers in the molecular layer showed interconnected anastomotic networks of ER tubules, vesicles and cisterns, whereas cross fractured presynaptic "en passant" endings of these fibers exhibited spheroidal synaptic vesicles and SE-I edge brightness contrast delineated their limiting plasma membranes. Parallel fiber fractured synaptic endings showed a homogeneous extravesicular material surrounding the synaptic vesicles. The neuroglial cytoplasm ensheathing nerve processes exhibited a smooth discontinuous surface. The high mass density surface of the myelin sheath showed a mixed population of globular structures, 10-30 nm, corresponding to protein and phospholipid microdomains.

Proteoglycan ultracytochemistry and conventional and high resolution scanning electron microscopy of vertebrate cerebellar parallel fiber presynaptic endings

The parallel fiber "en passant" synaptic endings of mouse cerebellar molecular layer have shown by means of transmission electron microscopy, the presence of an electron dense extravesicular material in samples perfused with Alcian blue. This alcianophilic material was digested in cerebellar tissue previously treated with testicular hyaluronidase, suggesting the presence of hyaluronic acid or chondroitin 4- or 6-sulphate. Freeze-fractured Rhesus monkey cerebellar cortex prepared for conventional scanning electron microscopy also revealed the presence in fractured synaptic varicosities of parallel fibers of a high mass density material, in which the synaptic vesicles are embedded. Examination of cryofractured primate cerebellar cortex coated with thin chromium films, 1-2 nm thick, in the high resolution field emission scanning electron microscope showed the SE-I topographic contrast of an extravesicular material deposited in axoplasmic matrix of fractured parallel synaptic endings. The precise localization of this material corresponds to that observed in transmission electron microscopy and conventional freeze-fracture scanning electron microscopy. These electron microscopic findings tend to agree with the omnipresence in several vertebrates of a presynaptic axoplasmic material, which seems to be proteoglycan in nature.

Three-dimensional morphology of cerebellar protoplasmic islands and proteoglycan content of mossy fiber glomerulus: a scanning and transmission electron microscope study

The present review summarizes the outer and inner surface features of mossy fiber glomeruli in vertebrate cerebellar granular layer as seen by conventional scanning electron microscopy (SEM) and SEM freeze-fracture method. The intracortical trajectory of mossy fibers and their synaptic contacts with granule cell dendrites were traced by the slicing and freeze-fracture techniques revealing the radial distribution of granule cell dendrites around the central mossy rosette. The "en passant" nature of mossy fiber synaptic contacts and the participation of Golgi cell axonal ramifications were demonstrated. The results obtained were compared with available light and transmission electron microscopy data. The freeze-etching technique disclosed the true extension of glomerular neuroglial investment. The proteoglycan content of mossy fiber rosette has been also studied by Alcian Blue staining, enzymatic digestion with testicular hyaluronidase and neuraminidase and Os-DMEDA staining method resulting in the presence of an electron dense material at the mossy fiber axoplasmic matrix and some synaptic vesicles, pre-and postsynaptic densities and cleft substance. The axoplasmic material appears to be constituted by proteoglycans with hyaluronic acid or chondroitin sulphate in their composition. The possible role of proteoglycans in synaptic functions is also discussed. Scanning electron microscopy is a promising methodology for analysis of short intracortical circuits and for the study of complex multisynaptic arrangements.

Scanning electron microscope, freeze etching and glycosaminoglycan cytochemical studies of the cerebellar climbing fiber system

Mouse and teleost fish cerebelli were processed by the freeze-fracture methods for scanning and transmission electron microscopy in order to study the three-dimensional morphology and intramembrane features of climbing fiber-Purkinje spine synapses. In addition, Alcian Blue and ruthenium chloride stainings were applied to mouse cerebellar tissue to investigate the polyanion composition of these excitatory synapses under the transmission electron microscope. In the granular layer, tendril and glomerular collaterals of climbing fibers were observed. In the molecular layer climbing fibers exhibited a characteristic crossing-over or arborescence pattern type of bifurcation, Scheibel's collaterals and multiple thorn synapses with Purkinje spiny dendrites. At the synaptic active zones of climbing fiber-Purkinje spine synapses the freeze-etching replicas showed focal aggregates of intramembrane particles at the E and P faces of the pre- and post-synaptic membranes. Membrane protuberances and pits were also observed at the pre-synaptic membrane. Ultracytochemical study of the climbing fiber synaptic varicosities revealed an Alcian Blue and ruthenium chloride positive material which appeared at the axoplasm surrounding the synaptic vesicles, at the pre- and post-synaptic densities and in the synaptic cleft. The axoplasmic material was sensitive to testicular hyaluronidase, therefore it would correspond to glycosaminoglycans (hyaluronic acid and/or chondroitin sulphates), which have been earlier reported in other cerebellar excitatory systems as those of mossy fiber-granule cell and parallel fiber-Purkinje dendritic spine.

Electron microscopy and glycosaminoglycan histochemistry of cerebellar stellate neurons

The stellate neurons of the cerebellar molecular layer have been mostly studied by light and transmission electron microscopy (TEM). However, the freeze-fracture scanning electron microscopy (SEM) and glycosaminoglycan histochemistry of these inhibitory microneurons have not been explored thus far. The freeze-etching technique, the freeze-fracture method for SEM and the conventional techniques for TEM were applied to cerebellar samples of Swiss albino mice and Arius spixii teleost fishes. In addition, Alcian Blue (AB) staining was applied to mouse cerebellar tissue in order to study glycosaminoglycan histochemistry. At the SEM level, the stellate neurons showed a short axonal plexus extending to the nearby secondary and tertiary Purkinje dendritic branches, and 2 to 4 conical dendrites receiving typical axo-dendritic synapses on their shafts. The fractured stellate neurons showed compact nuclear heterochromatin masses and the three dimensional interrelationship of ER and Golgi complex (Novikoff's GERL complex). The surface of the scarce endoplasmic reticulum was observed as strands extending from the nuclear envelope to the inner surface of the plasma membrane. At the TEM level, axosomatic endings of parallel and climbing fibers were distinguished. The cytochemical study revealed a homogeneous alcianophylic cytoplasmic substance, sensitive to hyaluronidase. This was particularly evident around and within the nucleus. The AB results indicated the presence of hyaluronic acid. A complex neuropil formed by Purkinje cell spiny branches, bundles of parallel fibers, spine synapses and Bergmann astrocytic cytoplasm was seen adjacent to the stellate neurons.

Histochemical demonstration of cytoplasmic glycosaminoglycans in the macroneurons of the human central nervous system

The presence of glycosaminoglycans (GAG) has been histochemically demonstrated in the CNS of various mammalian species. They have been related with some nerve functions as neurotransmitters storage and synaptic transmission. In the present paper, the histochemical properties of nerve cell cytoplasmic GAG were studied in several regions of adult human CNS. Samples of brain cortex, pons, upper medulla, and cerebellar cortex obtained by autopsy from subjects not dying after neurological diseases were fixed by immersion in glutaraldehyde, dehydrated with ethanol, and embedded in paraffin. The sections were stained with Alcian blue solutions adjusted to pH 2.5, 4.0, and 5.7. To the latter solution MgCl2 was added in increasing concentration from 0.05 to 1.2 M. Testicular hyaluronidase, neuraminidase, and ribonuclease were applied on simultaneous sections with their respective controls. The sequence of these reactions allowed us to demonstrate the presence of hyaluronic acid along chondroitin-4- and/or 6-sulphate in the cytoplasm of most nerve cells. The sulphated GAG showed certain variability in the various regions studied related specially with their grade of sulphation.

Application of alcian blue in the electron microscopic study of mouse and human cerebral cortex nerve cells

Alcian blue is a cationic dye which has been used in the histochemical field for the demonstration of polyanions especially carboxylated and sulphated. The results obtained in neurons when this dye was applied to human and mouse cerebral cortex and studied with the electron microscope are the object of the present report. The CNS of normal adult mice was fixed by vascular perfusion with 2% glutaraldehyde-0.1 M sodium cacodylate-0.1 M sucrose at pH = 6.8 followed by the same fixative with the addition of 0.5% alcian blue. After perfusion, brain cortex was taken out, sectioned into small blocks and immersed in a fresh similar mixture and subsequently in OSO4. Blocks were dehydrated and embedded in araldite. Ultrathin sections were doubly stained with uranyl and lead salts. Human brain cortex taken from patients with cerebral edema was fixed by immersion with 6.5% glutaraldehyde-0.1 M sodium phosphate, pH = 7.4 followed by embedding in warm agar and sectioning in slices of 30 mum thickness which were impregnated by immersion in a mixture of 1% alcian blue-acetate buffer-3% glutaraldehyde at pH = 3.5 for 9 to 15 h at 4 degrees C and subsequently immersed in 1% buffered OSO4-0.1 M sucrose, pH = 7.4 for 2 h at 4 degrees S. Sections were dehydrated and embedded in araldite. Ultrathin sections were doubly stained by uranyl and lead salts. We have denominated the complete procedure in both instances GABOUL technique. The submicroscopic study of both tissues, at nerve cells, revealed the presence of an electron dense homogeneous substance thoroughly dispersed at the hyaloplasmic matrix of perikarya, processes and even synaptic endings. This substance was more evident around free and attached ribosomes, GOLGI apparatus, complex vesicles, dense bodies, microtubules, subsurface cisternae and synaptic vesicles. Canaliculi of endoplasmic reticulum and even the perinuclear cistern also showed a moderate content. It is suggested that this electron dense substance, being alcianophilic, has a polyanionic character and thus may partially correspond to acid polysaccharides since these compounds have already been previously confirmed in such neurons by biochemical and light microscope histochemical techniques.