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At least 523 records · Page 29Linked to original sources
PubMed1988

The uptake and long-term storage of India ink particles and latex beads by fibroblasts in the dermis and subcutis of mice, with special regard to the non-inflammatory defense reaction by fibroblasts.

The fate of India ink particles and polystyrene latex beads injected into the dermis and subcutis of the skin of the auricle and back in mice was observed with the naked eye, light microscopy and electron microscopy. The tattoo patterns made by injected ink particles remained essentially unchanged for life as observed with the naked eye. India ink particles and latex beads were endocytosed by fibroblasts as well as macrophages in the dermis and subcutis. Numerous ink particles or small latex beads (0.22 micron in diameter) were packed into vacuoles 0.1-10.0 micron in diameter which occupied a large volume of the cytoplasm of the cell body and processes of fibroblasts, whereas numerous particles and larger beads (0.22 and 2.0 micron) were taken up into the cell body of macrophages in the vicinity. Most fibroblasts, characterized by long cell processes and well developed rough endoplasmic reticulum, are easily distinguished from macrophages, the latter being round or oval in shape, and having many lysosomes and numerous irregularly shaped microvillous projections. It is believed that fibroblasts taking up and storing the ink particles or latex beads move poorly and are almost fixed in the connective tissue: the tattoos therefore do not change markedly. It is emphasized that the uptake and long-term storage of ink particles and latex beads by the dermal and subcutaneous fibroblasts represent a specific non-inflammatory defense mechanism that protects the living body, without immune reactions, against injuries and invasions by non-toxic foreign agencies. The histiocyte, a term proposed by KIYONO (1914) for a fixed macrophage on the basis of his studies using vital dye staining, is considered to include, in addition to true macrophages, fibroblasts showing endocytotic activities for small foreign bodies such as acid dyes, ink particles, and latex beads.

Animals↗
PubMed1976

A quantitative electron microscopic study of the ageing human cerebral cortex.

A recent quantitative electron microscopic study of biopsy samples of the cerebral cortex of neurologically normal individuals, aged between 15 and 54 years, has shown that atypical inclusions are present in neuronal and glial processes in small but appreciable numbers (Rees). It would be of interest to know whether these inclusions accumulate with age. This study therefore applied the same quantitative methods used in the previous study, to autopsy samples of frontal and temporal cortex from 3 non-demented ageing human brains (70-76 years). The results showed that in the areas of cortex examined, the number of inclusions in neuronal processes did not increase with age. However, the number of dense deposits in the cell bodies and processes of oligodendrocytes did increase significantly with age. In agreement with previous studies corpora amylacea were found in astrocytic processes. Senile plaques were not observed.

Aged↗
PubMedDate not supplied

Müller cells in the retina of the cane toad, Bufo marinus, express neuropeptide Y-like immunoreactivity.

We have used light- and electron-microscopic immunohistochemistry to identify the presence of immunoreactivity to neuropeptide Y (NPY) within Müller cells in the retina of the cane toad, Bufo marinus. Müller cells containing NPY-like immunoreactivity (NPY-LI) were identified at the light-microscopic level by the coexistence with immunoreactivity to glial fibrillary acidic protein (GFAP) and at the ultrastructural level by their characteristic relationship to neuron cell bodies and processes. At the light-microscopic level, those cells which contained both NPY-LI and GFAP-LI usually had small cell bodies in the inner nuclear layer, while those cells which contained only NPY-LI were identified as large and small amacrine cells. The radially oriented primary processes in the inner plexiform layer and the vitreal end feet of GFAP-LI Müller cells also expressed NPY-LI. At the ultrastructural level, thin lamellar processes of Müller cells with NPY-LI enclosed some amacrine cell bodies in the inner nuclear layer and amacrine cell dendrites in the inner plexiform layer. These observations suggest that NPY-LI is localized in Müller cells in addition to two types of amacrine cells previously identified in the Bufo retina. This study provides the first evidence that glial elements in the vertebrate retina express NPY-LI.

Animals↗
PubMed2006

An intimate collaboration between peroxisomes and lipid bodies.

Although peroxisomes oxidize lipids, the metabolism of lipid bodies and peroxisomes is thought to be largely uncoupled from one another. In this study, using oleic acid-cultured Saccharomyces cerevisiae as a model system, we provide evidence that lipid bodies and peroxisomes have a close physiological relationship. Peroxisomes adhere stably to lipid bodies, and they can even extend processes into lipid body cores. Biochemical experiments and proteomic analysis of the purified lipid bodies suggest that these processes are limited to enzymes of fatty acid beta oxidation. Peroxisomes that are unable to oxidize fatty acids promote novel structures within lipid bodies ("gnarls"), which may be organized arrays of accumulated free fatty acids. However, gnarls are suppressed, and fatty acids are not accumulated in the absence of peroxisomal membranes. Our results suggest that the extensive physical contact between peroxisomes and lipid bodies promotes the coupling of lipolysis within lipid bodies with peroxisomal fatty acid oxidation.

Acyl-CoA Oxidase↗
PubMed1993

Selective attention to food and body shape words in dieters and restrained nondieters.

The current study investigated the presence of an attentional bias towards the processing of body shape and food-related material amongst noneating disordered women. Subjects carried out a computer-based Stroop color-naming task in which they had to name the colors of food-related words, body shape-related words, and two sets of matched neutral words. Significant color-naming disruptions of both food and body shape-related material were found for highly restrained eaters, irrespective of whether they were currently dieting. There were no reliable differences in color-naming times found for low to medium restrained eaters. Procedural differences probably account for the failure of previous studies to reveal such effects in nonclinical groups.

Adolescent↗
PubMed1989

Monoclonal antibody markers for amphibian oligodendrocytes and neurons.

Few immunocytochemical probes have been developed for cold-blooded vertebrates, thus hampering analyses of cellular processes in these species. Those developed from mammalian and avian tissue often fail either to react or to show similar specificities in poikilotherms. Therefore, we have begun raising monoclonal antibodies (mabs) in mice against frog and tadpole brain tissue. The following analyses of two of these mabs suggest that these antibodies represent specific probes for frog axons and oligodendrocytes. Mab Olig recognizes all the myelinated axon tracts of the mature frog brain and spinal cord, as well as the tracts of the developing tadpole CNS once they have become myelinated. Axons cut in cross section show characteristic o-shaped staining around individual axons when processed with this antibody. Particularly easy to visualize in the tadpole are immunoreactive cell bodies and processes, seen in continuity with the myelin sheath. Occasionally, in this developing tissue, cells with highly branched processes characteristic of immature oligodendrocytes are observed. No other cells or processes within the brain or spinal cord react with this antibody. Mab Linc stains numerous filaments in all axonal projections. Occasionally, a thin rim of filamentous staining is observed in cell somata, but many regions rich in neuronal somata or dendrites are unreactive to this antibody. This in vivo staining pattern suggests that the Linc antigen is differentially distributed within neurons and exhibits a high concentration in axons. Linc immunoreactivity is robust in the processes of a subpopulation of dissociated tectal cells in culture. These Linc-positive cells are characterized as neurons on morphological criteria. Also, intense Linc immunoreactivity is present in the bundles of retinal axons that extend from retinal explants. Olig immunoreactivity, however, has not been detected in tectal cultures or retinal explants. Improved staining following Triton X-100 treatment of tissue sections suggests that neither of the mabs recognizes lipid antigens and that both are probably localized within the cell cytoplasm. Only the Linc mab reacts on Western blots of denatured brain protein. Linc consistently recognizes two Triton X-100-insoluble proteins with apparent molecular weights of 56 and 58 kD. The epitopes recognized by the Olig and Linc mabs have been surveyed in terms of their resistance to optic nerve crush and their consequent value in studies requiring such procedures. Possible homologies to known cell-type-specific molecules are discussed.

Animals↗
PubMed1994

Early embryonic expression of a 60-kD glycoprotein in the developing nervous system of the lobster.

To investigate the developmental processes that generate the crustacean nervous system, we used a monoclonal antibody that recognises an antigen that is expressed in the developing embryonic nervous system of the lobster, Homarus gammarus. Expression of this antigen commences early in embryogenesis, occurs in all parts of the embryonic central and peripheral nervous systems, and continues into adulthood. Initial expression in the central nervous system correlates with the onset of neuronal process outgrowth. Light microscopic analysis shows that the antigen is found surrounding the cell bodies and processes of all neurons. Biochemical analysis indicates that the antigen is a glycoprotein with an apparent molecular weight of 60 kD. Due to the early embryonic onset of its expression, this antigen is a useful cellular label for visualisation of pattern formation in the developing nervous system; this is documented in detail for the developing stomatogastric nervous system. The fact that the 60-kD antigen is expressed early in embryogenesis throughout the nervous system suggests that it might play an important role in the development of the lobster nervous system.

Animals↗
PubMed2005

Interaction of Wnt and caudal-related genes in zebrafish posterior body formation.

Although Wnt signaling plays an important role in body patterning during early vertebrate embryogenesis, the mechanisms by which Wnts control the individual processes of body patterning are largely unknown. In zebrafish, wnt3a and wnt8 are expressed in overlapping domains in the blastoderm margin and later in the tailbud. The combined inhibition of Wnt3a and Wnt8 by antisense morpholino oligonucleotides led to anteriorization of the neuroectoderm, expansion of the dorsal organizer, and loss of the posterior body structure-a more severe phenotype than with inhibition of each Wnt alone-indicating a redundant role for Wnt3a and Wnt8. The ventrally expressed homeobox genes vox, vent, and ved mediated Wnt3a/Wnt8 signaling to restrict the organizer domain. Of posterior body-formation genes, expression of the caudal-related cdx1a and cdx4/kugelig, but not bmps or cyclops, was strongly reduced in the wnt3a/wnt8 morphant embryos. Like the wnt3a/wnt8 morphant embryos, cdx1a/cdx4 morphant embryos displayed complete loss of the tail structure, suggesting that Cdx1a and Cdx4 mediate Wnt-dependent posterior body formation. We also found that cdx1a and cdx4 expression is dependent on Fgf signaling. hoxa9a and hoxb7a expression was down-regulated in the wnt3a/wnt8 and cdx1a/cdx4 morphant embryos, and in embryos with defects in Fgf signaling. Fgf signaling was required for Cdx-mediated hoxa9a expression. Both the wnt3a/wnt8 and cdx1a/cdx4 morphant embryos failed to promote somitogenesis during mid-segmentation. These data indicate that the cdx genes mediate Wnt signaling and play essential roles in the morphogenesis of the posterior body in zebrafish.

Animals↗
PubMed1997

Autoradiographic studies on the uptake of 3H-dopamine by neurons and astrocytes in explant and primary cultures of rat CNS: effects of uptake inhibitors.

The cellular localization of the uptake of 3H-dopamine was studies in explant and primary cultures from various regions of rat central nervous system by means of autoradiography. In explant cultures of substantia nigra, 3H-dopamine was taken up by cell bodies and processes of many neurons. In cultures from striatum, cerebellum and spinal cord, neuronal cell bodies were not labelled, whereas outgrowing nerve fibres revealed intense uptake of the monoamine. Uptake of 3H-dopamine by neurons was Na(+)- and temperature-dependent, suggesting an active uptake mechanism. In explant cultures, astrocytes did not accumulate 3H-dopamine, whereas in primary cultures, which were prepared from the same regions of rat central nervous system as the explant cultures, astrocytes also revealed uptake of this monoamine. The intensity of labelling was dependent on the incubation time. Little uptake of 3H-dopamine was observed after an incubation time of 5 min and only after 10-15 min did the astrocytes show moderate labelling. Uptake of 3H-dopamine by astrocytes was not Na(+)- and temperature-dependent, indicating that glial cells do not possess an active uptake mechanism for this monoamine. This is consistent with biochemical investigations by other laboratories, demonstrating that astrocytes accumulate 3H-dopamine by a facilitated diffusion system. Addition of the uptake inhibitors nomifensine or GBR 12909 to explant cultures markedly reduced or inhibited uptake of 3H-dopamine by neurons at a concentration of 10(-6) M. In contrast, accumulation of 3H-dopamine by astrocytes in primary cultures was only slightly affected by nomifensine at 10(-6) M. At the highest concentration used (10(-5) M), nomifensine also blocked the uptake of 3H-dopamine by astrocytes. Our finding that GBR 12909 almost completely inhibited the uptake of 3H-dopamine by astrocytes already at 10(-6) M suggests that this compound is a more potent inhibitor of the glial uptake of dopamine than nomifensine.

Animals↗
PubMed2002

Proteasome inhibition causes nigral degeneration with inclusion bodies in rats.

Structural and functional defects in 26/20S proteasomes occur in the substantia nigra pars compacta and may underlie protein accumulation, Lewy body formation and dopaminergic neuronal death in Parkinson's disease. We therefore determined the pathogenicity of proteasomal impairment following stereotaxic unilateral infusion of lactacystin, a selective proteasome inhibitor, into the substantia nigra pars compacta of rats. These animals became progressively bradykinetic, adopted a stooped posture and displayed contralateral head tilting. Administration of apomorphine to lactacystin-treated rats reversed behavioral abnormalities and induced contralateral rotations. Lactacystin caused dose-dependent degeneration of dopaminergic cell bodies and processes with the cytoplasmic accumulation and aggregation of alpha-synuclein to form inclusion bodies. These findings support the notion that failure of the ubiquitin-proteasome system to degrade and clear unwanted proteins is an important etiopathogenic factor in Parkinson's disease.

Acetylcysteine↗
PubMed1981

[Dynamics of the concentration of cyclic adenosine monophosphate in the tissues of rats with insulin hypoglycemia].

The paper is concerned with the data on the cAMP content in rat tissues 15, 30, 60 and 120 minutes after insulin injection. Rapidly developing heterogenous changes were recorded in the cAMP content of rat tissues during insulin-induced hypoglycemia and stress reaction. The evidence obtained indicates that during stress reaction the line of the changes in the entire body depends on the triggering of numerous neurohumoral mechanisms that regulate the most essential processes of body activity via the adenylate cyclase system.

Adipose Tissue↗
PubMedDate not supplied

GABA immunoreactivity in the human cerebellar cortex: a light and electron microscopical study.

The distribution of gamma-aminobutyric acid (GABA) in surgical samples of human cerebellar cortex was studied by light and electron microscope immunocytochemistry using a polyclonal antibody generated in rabbit against GABA coupled to bovine serum albumin with glutaraldehyde. Observations by light microscopy revealed immunostained neuronal bodies and processes as well as axon terminals in all layers of the cerebellar cortex. Perikarya of stellate, basket and Golgi neurons showed evident GABA immunoreactivity. In contrast, perikarya of Purkinje neurons appeared to be negative or weakly positive. Immunoreactive tracts of longitudinally- or obliquely-sectioned neuronal processes and punctate elements, corresponding to axon terminals or cross-sectioned neuronal processes, showed a layer-specific pattern of distribution and were seen on the surface of neuronal bodies, in the neuropil and at microvessel walls. Electron microscope observations mainly focussed on the analysis of GABA-labelled axon terminals and of their relationships with neurons and microvessels. GABA-labelled terminals contained gold particles associated with pleomorphic vesicles and mitochondria and established symmetric synapses with neuronal bodies and dendrites in all cortex layers. GABA-labelled terminals associated with capillaries were seen to contact the perivascular glial processes, basal lamina and endothelial cells and to establish synapses with subendothelial unlabelled axons.

Aged↗
PubMed1978

Morphologic and cytochemical properties of a clonal line of rat adrenal pheochromocytoma cells which respond to nerve growth factor.

The PC12 pheochromocytoma line is a clonal line derived from a rat adrenal medullary tumor. PC12 cells grown in vitro have morphologic and cytochemical features in common with normal chromaffin cells in varying stages of development, and with human pheochromocytomas. These features include catecholamine stores demonstrable by formaldehyde-induced fluorescence and argentaffinic secretory granules, measuring 30 to 350 nm. Dark "norepinephrine"- and light "epinephrine"-type granules are both present, despite the absence of epinephrine and of its synthesizing enzyme, phenylethanolamine N-methyltransferase. Addition of nerve growth factor to the culture medium causes the cells to stop dividing and to develop neurite-like processes. Nerve growth factor-treated cells also develop clusters of 30- to 120-nm. granules and of 30- to 70-nm. granular and agranular vesicles, which resemble the granules and vesicles in adrenergic and cholinergic neurons and in neuroblastomas. In the early stages of process formation, formaldehyde-induced fluorescence can be demonstrated both in cell bodies and in processes. In later stages there is a marked diminution of formaldehyde-induced fluorescence in cell bodies and processes and a decreased number of granules in cell bodies, except in occasional cells within large clumps. These residual, fluorescent, granule-containing cells also remain argentaffinic. Alterations of the cell surface and of cytoplasmic filament arrangements also occur in cells treated with nerve growth factor. Further studies of the PC12 line may help to clarify relationships between morphology and function in the developing and mature autonomic nervous system, and the influence of nerve growth factor on these relationships.

Adrenal Gland Neoplasms↗
PubMed1989

Immunohistochemical localization of myelin basic protein and 2',3'-cyclic nucleotide 3'-phosphohydrolase in flattened membrane expansions produced by cultured oligodendrocytes.

Oligodendrocytes, the cells responsible for myelin sheath formation in the central nervous system, were isolated from primary dissociated mixed glial cultures prepared from newborn mouse forebrain, and further cultured in a serum-free defined culture medium. Single and double indirect immunofluorescence using antibodies against the myelin glycolipids, galactocerebroside and sulfatide, and the myelin proteins, myelin basic protein and 2',3'-cyclic nucleotide 3'-phosphohydrolase, was used to investigate the composition of the flat membrane extensions produced by some oligodendrocytes in culture. Galactocerebroside and sulfatide were both expressed on the external surface of the plasma membrane of oligodendrocyte cell bodies and processes and also the membrane expansions. Neither myelin basic protein nor 2',3'-cyclic nucleotide 3'-phosphohydrolase were expressed on the external surface of oligodendrocytes. Myelin basic protein could be localized to the cell body and the membrane expansions but not the major and fine processes. The localization of these myelin components suggests that the expansions have characteristics of the mature myelin membrane. 2',3'-Cyclic nucleotide 3'-phosphohydrolase was found to be localized in the cell body, and in total contrast to myelin basic protein, in the major processes and the fine interconnecting processes, but not the membrane expansions. In some of the cells 2',3'-cyclic nucleotide 3'-phosphohydrolase was present at the outer extremities of the flat membrane sheets, giving the appearance of an extending growth region. Our results thus clearly show that 2',3'-cyclic nucleotide 3'-phosphohydrolase is localized within oligodendrocytes in discrete regions of plasma membranes and suggest that this protein has a possible role in the early stages of myelin formation.

2',3'-Cyclic-Nucleotide Phosphodiesterases↗
PubMed1998

Radioactive fucose as a tool for studying glycoprotein secretion.

The efficiency and reliability of radioactive fucose as a specific label for newly synthesized glycoproteins were investigated. Young adult male rabbits were injected intravitreally with [3H]-fucose, [3H]-galactose. [3H]-mannose, N-acetyl-[3H]-glucosamine or N-acetyl-[3H]-mannosamine, and killed 40 h after injection. In another series of experiments rabbits were injected with either [3H]-fucose or several tritiated amino acids and the specific activity of the vitreous proteins was determined. Vitreous samples were also processed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and histological sections of retina, ciliary body and lens (the eye components around the vitreous body) were processed for radioautography. The specific activity (counts per minute per microgram of protein) of the glycoproteins labeled with [3H]-fucose was always much higher than that of the proteins labeled with any of the other monosaccharides or any of the amino acids. There was a good correlation between the specific activity of the proteins labeled by any of the above precursors and the density of the vitreous protein bands detected by fluorography. This was also true for the silver grain density on the radioautographs of the histological sections of retina, ciliary body and lens. The contribution of radioautography (after [3H]-fucose administration) to the elucidation of the biogenesis of lysosomal and membrane glycoproteins and to the determination of the intracellular process of protein secretion was reviewed. Radioactive fucose is the precursor of choice for studying glycoprotein secretion because it is specific, efficient and practical for this purpose.

Animals↗
PubMed2004

Identification and cellular localisation of NPW1 (GPR7) receptors for the novel neuropeptide W-23 by [125I]-NPW radioligand binding and immunocytochemistry.

Using a novel radioligand, we have identified high-affinity binding sites (K(D)=0.44+/-0.13 nM) for the recently discovered peptide, neuropeptide W (NPW), in rat brain. Binding density was highest in the amygdala (B(max)=149.9+/-13.8 fmol/mg protein), thalamic, and hypothalamic nuclei. A similar distribution was observed in mouse brain. We have confirmed the identity of these binding sites as the G-protein-coupled receptor, NPW(1) (previously designated orphan receptor GPR7), using site-directed antisera that revealed receptors were expressed by neuronal cell bodies and processes. Additionally, we have demonstrated the presence of NPW-like immunoreactivity in neuronal cell bodies in areas projecting to the amygdala, such as the dorsal raphe nucleus and ventral tegmental area, providing evidence for an emerging new transmitter system.

Animals↗
PubMedDate not supplied

Truth and reconciliation: a psycholegal perspective.

The South African Truth and Reconciliation Commission ('TRC') represents one model of dealing with human rights abuses at a national level. Such abuses, and the subsequent attempts to come to terms with them, can cause mental disorders and psychological pain. Consequently, mental health and mental health practitioners ('practitioners') will play an important role in the process of bodies such as the TRC. The aim of this article is to examine the TRC process from a psycholegal perspective and to recommend which aspects thereof can be improved in the future. For example, the use of terminology such as 'victim' and 'perpetrator' during the process may have influenced how participants were perceived and treated. Likewise, the emphasis on collective, rather than individual interests, restricted the role of survivors and amnesty seekers in the TRC process. This reduced the effectiveness of the TRC in bringing about reconciliation at an individual and a national level, and limited the TRC's potential as a therapeutic agent. Nevertheless, there were claims that the TRC process healed people. It is argued that the process in itself usually did not lead to healing. Instead, the TRC process highlighted great mental health needs, which were not adequately met. The article discusses the factors that make it difficult to meet mental health needs in countries where human rights abuses have taken place. The article then considers strategies to meet these needs and emphasizes how important it is that those who render mental health services are competent and seen to be credible by the consumers of such services. Finally, the article addresses the need for research in this field to be co-ordinated and professionally responsible.

Ethnicity↗