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F Gallyas

Publications and source records attributed to F Gallyas.

At least 37 records · Page 2Linked to original sources
PubMed1993

Four modified silver methods for thick sections of formaldehyde-fixed mammalian central nervous tissue: 'dark' neurons, perikarya of all neurons, microglial cells and capillaries.

Four reliable silver methods for the visualization of acute or advanced phases of neuronal damage have been modified so that they can be performed with good results on materials freshly fixed with transcardial perfusion of buffered formaldehyde for other silver methods and immunocytochemical techniques. The four modified methods respectively stain: (1) the somata and dendrites of 'dark' (impaired) neurons, (2) the perikarya of all neurons, (3) microglial cells, and (4) capillaries. Without the present modifications the 'dark' neuron method is only effective with glutaraldehyde fixation while the other three methods predominantly stain myelin in freshly fixed mammalian nervous tissue.

Animals↗
PubMed1993

Silver staining as a tool for neurotoxic assessment.

There is no denying that the silver methods lost their dominant role as tract-tracing methods in the past 10 to 15 years. But it seems equally clear that the silver technique is headed for a dramatic revival in many fields of neuroscience, where the scope and localization of neuronal degeneration are a central issue. Together with the immunostaining of proteins formed or altered in traumatized neurons, the modern silver techniques provide neurotoxicologists and neuropathologists with unparalleled opportunities to detect and study injured and dying neurons. Characterized by great sensitivity and distinct rendition of the morphology of degenerating neurons and their processes, the reduced silver methods constitute the ideal tool for screening irreversible neuronal damage caused by neurotoxic substances including drugs of abuse. Those interested in the rapidly expanding fields of "excitotoxicity" and neurodegenerative disorders (Taylor 1991) are also likely to find increasing use for the silver methods. The pattern of degeneration in so-called "system degenerations" may be predetermined by the neuronal connections (Saper et al. 1987), and as the disease progresses from the destruction of the originally affected neuron population, closely related systems and pathways may be recruited into the pathophysiologic cascade. Any type of trauma to the CNS has the potential to produce this type of "domino effect" of degeneration, through which additional systems are progressively recruited into a degenerative chain reaction of transneuronal degeneration. In other words, even longstanding disorders may exhibit signs of more recent degeneration, and the proper use of silver methods at autopsy may give some important clues regarding the etiology of disease; it may also provide new insights about the anatomy of the human brain. Little can be said at present about the chemical basis of argyrophilia in degenerating and "reactive" neurons, but there is every reason to pay more attention to this subject. One can expect that a continuing and concerted effort will result in a rational understanding of the molecular biological and physicochemical events that fortuitously provide the basis for the selective impregnation of degenerating neuronal elements. This knowledge can be the basis for the development of even more reliable and simple, yet sensitive, silver methods suited for neurotoxic risk assessment on a large scale.

Animals↗
PubMed1993

An immediate morphopathologic response of neurons to electroshock; a reliable model for producing "dark" neurons in experimental neuropathology.

Ninety rats were electroshocked by a single condenser discharge 1 min. prior to perfusion fixation and delayed autopsy. Voltage and capacity of the condenser as well as surface area and position of the electrodes were varied between 125 and 1250 V, 20 and 200 microF, 2 and 24 mm2, and frontal to posterior, respectively. Within these ranges the electroshock rendered a varying number of brain neurons together with their dendritic arborization stainable by a special silver method. In toluidine blue preparations both somata and nuclei of these neurons appeared markedly shrunken and hyperchromatic, indicating morphological damage ("dark" neuron). A 250-V shock damaged only granule neurons of the hippocampal dentate gyrus. After a 750-V shock it was the substantia nigra, the lateral septal nucleus, the anterior amygdaloid area, and the lateral preoptic area that consistently contained electrically damaged neurons, without other kinds of parenchymal damage.

Animals↗
PubMed1992

Delayed degeneration of the optic tract and neurons in the superior colliculus after forebrain ischemia.

Neuronal damage induced by 15-min forebrain ischemia was investigated in adult rats 1-5 days (short-term group) and 1-5 months (long-term group) after the initial ischemic attack. In addition to the vulnerable areas reported previously, we observed that the optic tract was also very susceptible. Degeneration of the optic tract and subsequent transsynaptic cell death in the superior colliculus developed slowly and was observed only in the long-term group. The delayed, progressive neuronal damage in this sensory system may serve as a suitable model to investigate the mechanisms of long-term changes in the injured brain.

Animals↗
PubMed1992

Coexistence of cholinergic, catecholaminergic, serotonergic, and glutamatergic neurotransmitter markers in mouse clonal hybrid neurons derived from the septal region.

Two clonal immortalized neurons designated SN6.1b and SN6.2a were isolated by limiting dilution from a mouse embryonic septal cholinergic neuronal hybrid cell line SN6 (Hammond et al., 1986). In the serum-containing medium without extra differentiating agents, one-third of SN6.1b cells stably exhibited a morphology of differentiated neurons with extensive elaborate neurites, while a majority of SN6.2a cells, along with the parent cell line SN6, were round in shape with poorly branched short processes. Neurochemical studies showed that both clones synthesized choline acetyltransferase (ChAT), dopamine, norepinephrine, serotonin, and glutamate. Immunocytochemically, they expressed a number of neuronal antigens, such as 200-kDa neurofilament protein, neuron-specific enolase, microtubule-associated protein 2, tau protein, tubulin, neural cell adhesion molecule, Thy-1.2, saxitoxin-binding sodium channel protein, ChAT, tyrosine hydroxylase, serotonin, and glutamate. The coexistence of cholinergic, catecholaminergic, serotonergic, and glutamatergic neurotransmitter markers in the clonal hybrid septal neurons that express a variety of immunocytochemical properties of differentiated neurons suggests that embryonic septal cholinergic neurons are potentially multiphenotypic with respect to neurotransmitter synthesis.

Amino Acids↗
PubMed1992

Establishment of mouse-immortalized hybrid clones expressing characteristics of differentiated neurons derived from the cerebellar and brain stem regions.

Two clonal immortalized neurons designated CL8c4.7 and CL8a5.2 were established by somatic cell fusion between a hypoxanthine phosphoribosyltransferase-(HPRT-) deficient neuroblastoma N18TG2 and newborn mouse cerebellar/brain stem neurons. In the serum-containing medium without extra differentiating agents, both clones exhibited a morphology of differentiated neurons. They contained high levels of glutamate but no gamma-aminobutyric acid (GABA). The CL8a5.2 clone synthesized choline acetyltransferase and serotonin. In immunocytochemical studies, both clones expressed 200 kD neurofilament protein, neuron-specific enolase, microtubule-associated protein 2 (MAP2), tau protein, neuronal cell adhesion molecule (N-CAM), HNK-1, Thy-1.2, saxitoxin-binding sodium channel protein, and glutamate. Synaptophysin immunoreactivity was identified in the neuritic terminals of CL8c4.7 cells. Most of these antigens were barely detectable on N18TG2 cells. Electrophysiologically, both clones generated action potentials in response to electrical stimuli. The hybrid clones that express characteristics of differentiated neurons derived from the cerebellar and brain stem regions might be invaluable for the study of the molecular basis of neuronal differentiation and degeneration in these regions.

Amino Acids↗
PubMed1992

Light microscopic response of neuronal somata, dendrites and axons to post-mortem concussive head injury.

Forty anesthetized rats were cooled below 3 degrees C by 30-min transcardial perfusion of chilled physiological saline before a concussive head injury. The animals were then perfusion-fixed with a buffered formaldehyde-glutaraldehyde solution. Another forty rats were fixed by 30-min transcardial perfusion of the same fixative before a similar concussive head injury. In brain sections of both groups of animals a new silver method stained, in a Golgi-like fashion, a number of neurons and long axonal segments scattered among unstained ones. The similarity between these findings and those obtained following in vivo concussive head injuries described in accompanying papers suggests that the formation of traumatically induced argyrophilic neuronal damage is independent of metabolic processes, i.e., it may be a primary morphopathological process.

Animals↗
PubMed1992

Formation of "dark" (argyrophilic) neurons of various origin proceeds with a common mechanism of biophysical nature (a novel hypothesis).

Based on recent findings described in accompanying reports as well as on relevant observations in the literature we hypothesize that: (1) the fundamental elements in the mechanism of the formation of "dark" (argyrophilic) neurons are independent of the causative conditions including post-mortem or in vivo mechanical injuries and various in vivo pathometabolic processes such as blood recirculation following ischemia; (2) the causative conditions, each in its own mechanical or metabolic way, induce the same morphopathological damage at one point only within each affected neuron; (3) this damage spreads throughout the respective somato-dendritic or axonal domain and entails type III argyrophilia; (4) the intraneuronal spread of the morphopathological damage consumes mechanical energy stored by the neurofilaments in the form of a metastable inner structure, and (5) is propagated by a process working, in certain structural and energetical respects, on the domino principle; and (6) the primary neuronal damage caused in the above manner might be secondarily modified in different directions by different postcausation conditions.

Animals↗
PubMed1992

An immediate light microscopic response of neuronal somata, dendrites and axons to non-contusing concussive head injury in the rat.

Sixteen rats were killed by transcardial perfusion fixation 1 min after a non-contusing concussive head injury, and seven rats 1 day later. In each of the "1-min" animals Golgi-like neurons and long axonal segments scattered in various proportions among unstained neurons and axons were demonstrated by a new silver method both near to and far from the impact site in a parenchymal environment unaffected by contusion. The silver-stained neurons, dendrites and axons were considered to have been damaged by the trauma because they were consistently absent from control brains. In the "1-day" brains silver-stained dendrites and axons had a beaded appearance, indicating an advanced stage of morphopathological damage. From details of these findings the following conclusions were drawn: (1) trauma can directly induce some kind of morphopathological damage in neurons which manifests itself in shrinkage of the soma and tortuosity of appendages as well as in type III argyrophilia; (2) different vulnerability of various brain areas is likely due to the inhomogeneity of the trauma-induced pressure wave propagating through the brain; and (3) the somato-dendritic and axonal domains of the neuron are selectively vulnerable to different values of the parameters of the intracranial pressure wave.

Animals↗
PubMed1992

An immediate light microscopic response of neuronal somata, dendrites and axons to contusing concussive head injury in the rat.

Thirty-four rats were killed by transcardial perfusion fixation 1 min after a contusing concussive head injury, and 17 rats 1 day later. From the results obtained with a new silver method demonstrating traumatically damaged neuronal somata, dendrites and axons the following conclusions were drawn: (1) outside the contused territories all features of traumatically induced neuronal argyrophilia are similar to those found in non-contusing concussive head injury, as reported in an accompanying paper; (2) within contused territories the neuronal argyrophilia is abolished by some substance released either from damaged blood vessels or damage parenchymal cells, while the neuronal damage otherwise underlying the induction of argyrophilia is present; (3) different phenotypes of neurons are vulnerable to different values of the parameters of the intracranial pressure wave generated by the trauma; (4) some of the neurons may recover from the traumatically induced argyrophilic damage; (5) traumatically induced inundation of neurons with extracellular tracers, as reported by other authors, and somato-dendritic argyrophilia may be different manifestations of one and the same phenomenon; and (6) diffuse primary traumatic axonal injury in human neuropathology may be closely correlated to axonal argyrophilia.

Animals↗
PubMed1990

Trauma-induced Golgi-like staining of neurons: a new approach to neuronal organization and response to injury.

A new esterification-silver approach to the directed staining of the dendritic trees of traumatized neurons is described. Stained neurons compare favorably to those labeled with silver chromate Golgi impregnations in the visualization of dendritic arbors. Cells in all parts of the brain, including the hypothalamus, hippocampus, cerebral cortex, cerebellum, striatum, spinal cord, thalamus, and olfactory bulb, can be detected after focal trauma to that region. Selection of neurons to be stained is made by increasing their affinity for silver with many different types of directed neuronal trauma, including micropipette wounds, pressure, surgical incision, chemical cytotoxicity, and impact trauma. Trauma to one area of the brain results in dendritic arbors staining only in the injured area; other areas of the brain are free of dendritic staining. Injury can be produced either in vivo or in vitro. In vitro injury to neurons allows a high degree of localization and facilitates the analysis of neuronal response to trauma in the absence of complicating factors such as blood flow and secondary injury. The selective affinity for silver staining in this approach is increased very rapidly, allowing detection of traumatized cells fixed minutes after injury. Brains of all mammals used appear to stain similarly, including the rat, mouse, pig, and human. Axons, although labeled less frequently than dendritic arbors, are induced to stain just as rapidly as dendrites. The ability to visualize a large part of the dendritic tree after trauma allows the segregation of neuronal subtypes on the basis of their differential response to injury. Subpopulations of cells in the same area of the brain appear to respond differently to trauma. Differential response of neurons to trauma can easily be detected. For instance, slight variations in trauma can be used to label selectively the major subpopulations of neurons in the hippocampus, including pyramidal cells, interneurons near the pyramidal cell layer, or granule cells. Similarly, neurons of the hypothalamic paraventricular and arcuate nuclei respond to compression trauma much more dramatically than other cell types in the same region of the hypothalamus. Hypothalamic neurons were studied extensively, particularly in regions that are difficult to routinely stain with Golgi impregnations, including the arcuate, paraventricular, supraoptic, and suprachiasmatic nuclei. Trauma to these areas was made in vitro after removal of the brain from the skull, allowing easy access to the ventral surface of the brain.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1990

Golgi-like demonstration of "dark" neurons with an argyrophil III method for experimental neuropathology.

A silver method is proposed for the selective, well-contrasted and reproducible demonstration of "dark" neurons in frozen, vibratome and paraffin sections cut at a thickness of 5 to 200 microns from aldehyde-fixed brains. The Golgi-like staining of the dendrites enables assorting of "dark" neurons according to characteristic neuron classifications. The staining procedure includes an esterification with 1-propanol, a treatment with diluted acetic acid and development. The esterification strongly increases the argyrophilia of both "dark" neurons and mitochondria. Unwanted co-staining of mitochondria is suppressed by the acetic acid treatment, while a special developer is used to render the staining controllable. The applicability of the method to experimental neuropathology is demonstrated by Golgi-like staining of "dark" neurons in rat brains exposed, before transcardial perfusion-fixation and delayed autopsy, to various pathological conditions including ischemia, hypoglycemia, trauma, status epilepticus, deafferentation and poisoning with kainic acid, colchicine and sodium azide, respectively.

Animals↗
PubMed1990

An argyrophil-III method for the selective demonstration of mitochondria in aldehyde-fixed rat brain.

Based on recent achievements in physicochemical aspects of histological silver staining, a selective and reliable method was elaborated for the demonstration of mitochondria in frozen sections of aldehyde-fixed rat brain. Areas of similar architecture were stained with comparable intensity both within one section or in serial sections. The distribution patterns of mitochondria can be examined at low magnification or even with the unaided eye. At high magnifications, rounded and elongated profiles with the size and shape of mitochondria clearly stand out against a pale background. Electron microscopy revealed a high degree of selectivity and completeness of the mitochondrial staining.

Aldehydes↗
PubMed1989

A highly sensitive one-step method for silver intensification of the nickel-diaminobenzidine endproduct of peroxidase reaction.

We have developed a new technique which makes silver intensification of the oxidatively polymerized diaminobenzidine (DAB), the endproduct of peroxidase reaction, less laborious without any loss in selectivity or sensitivity. The new technique is based on two strategies: (a) increasing the argyrophilia of the DAB by modifying its polymerization with Ni ions, and (b) decreasing tissue argyrophila by using a mildly acidic physical developer instead of the alkaline one previously presented. Because the nickel modification takes place in the DAB substrate solution, i.e., in the final step of the peroxidase reaction, only one additional step, the physical development, must be carried out if intensification is needed.

3,3'-Diaminobenzidine↗
PubMed1989

Cyclic AMP influences protein synthesis in larval brains of Drosophila melanogaster.

The protein synthesis in dissected whole larval brains of Drosophila melanogaster has been monitored by [35S] methionine incorporation, as revealed by two-dimensional gel-electrophoresis and fluorography. In wild type brains, drugs known to increase cAMP level increased the labelling of at least two proteins in the Mr range 30 to 120 kD and pI range 4.8 to 6.2. One of these proteins, Mr = 78 kD and pI = 5.9, was also enhanced in the dunceM11 memory-mutant, which has an elevated cAMP level, whereas it was hardly affected in the rutabaga memory-mutant, which has a subnormal cAMP level. It is suggested that cAMP-induced alterations in protein composition and/or turnover of nerve cells may contribute to the development of memory deficit in the dunce strains.

Animals↗
PubMed1988

Copper-H2O2 oxidation strikingly improves silver intensification of the nickel-diaminobenzidine (Ni-DAB) end-product of the peroxidase reaction.

We propose an improved silver procedure for intensification of peroxidase staining. It utilizes the high argyrophilia of polymerized Ni-DAB as a chromogen of peroxidase histochemistry, and the capacity of Cu++-catalyzed H2O2 oxidation to suppress tissue argyrophilia without influencing the argyrophilia of the polymerized Ni-DAB. This procedure is much more effective than any previously proposed intensification technique. When used in somatostatin histochemistry, it reveals perikarya, fibers, and nerve terminals in locations at which they have never been detected in preparations where only the DAB polymer was silver-intensified.

Copper↗
PubMed1987

Oxidation catalyzed by H+ ions improves the silver intensification of 3,3'-diaminobenzidine staining by strongly suppressing tissue argyrophilia.

We found that a 15-min treatment of tissue sections with 2 M/l H2O2 dissolved in 6 M/l sulphuric acid strongly suppresses the argyrophilia of tissue elements, thus facilitating selective silver intensification in histochemical procedures. When applied inserted between the 3,3'-diaminobenzidine reaction and physical development, this treatment allows the selective and sensitive visualization of very low levels of peroxidase activity.

3,3'-Diaminobenzidine↗