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PubMed2005

TiO2/UV/O3-BAC processes for removing refractory and hazardous pollutants in raw water.

TiO2/UV/O3-BAC (biological activated carbon) process was employed to treat raw water and compared to UV/O3-BAC process in its optimum parameters (3 mg/L ozone dosage with 15 min oxidation time and 15 min empty bed contact time in BAC). The results showed that the presence of TiO2 improved ozone utilization and biodegradability of the effluent. For the dissolved organic carbon (DOC) removal, TiO2/UV/O3-BAC was more efficient than UV/O3-BAC and its synergetic effect is more than that in UV/O(3)-BAC process. It was showed that small molecules with MW<3000 Da predominated in the raw water accounting for more than 56% DOC, they were increased after oxidation, accounting for more than 64% DOC. GC/MS analysis showed that TiO2/UV/O3-BAC process was effective in removing phthalate esters (PAEs) and persistent organic pollutants (POPs). PAEs' removal ratio reached more than 94% and reduced with the increase of the length of the alkyl side chains and the alkyl branch chains. TiO2/UV/O3-BAC process was also very effective in removing POPs. Polybromobiphenyls' removal rate reached more than 89% and decreased with the increase of substitutional bromines except for 2,2',5,5'-tetrabromobiphenyl, which can be completely removed.

Charcoal↗
PubMed1986

Crypt production in normal and diseased human colonic epithelium.

New crypts are added continuously to the adult mouse intestinal epithelium by a process of crypt replication. Branching crypts found in the epithelium represent a stage in the process of crypt replication. In "normal" human colonic epithelium we found a small but definite percentage of branching crypts, 0.44 +/- 0.16, indicating that new crypts are being produced at a low rate in this epithelium. Significantly higher (P less than .001) percentages of branching crypts, 30.4 +/- 5.75, 15.1 +/- 1.08, and 13.2 +/- 1.05, were found in diseased colonic epithelium from patients with ulcerative colitis, Crohn's disease, and multiple polyposis, respectively. These results may be interpreted as suggesting that the rate of crypt production in human colonic epithelium is increased in a number of disease states. We concluded that, as in the mouse intestinal epithelium, the rate of the crypt replication process in human colonic epithelium is plastic and may respond to a variety of conditions.

Aged↗
PubMed1994

Calcium-binding protein parvalbumin-immunoreactive neurons in the rat olfactory bulb. 2. Postnatal development.

The laminar development of the external plexiform layer (EPL) in the rat main olfactory bulb and the postnatal development of parvalbumin-immunoreactive [PV(+)] neurons mainly located in this layer were studied in animals at postnatal week 1-4 at a light microscopic level. The EPL in the adult olfactory bulb consists of two sublayers, the inner sublayer (ISL) and the outer sublayer (OSL). The ISL was already developed well even at postnatal day 7 (P7), whereas the OSL was first recognized at P10 as a thin zone consisting of more or less loosely packed large-sized and small-to-medium-sized somata subjacent to the glomerular layer (GL). The OSL increased in thickness and came to occupy nearly one-third to -half of the EPL at P14. PV(+) neurons first appeared at P10 mainly in the inner border of EPL. Only a few PV(+) neurons were scattered in the EPL at P10, but they increased remarkably in number during P14-21. Some of these PV(+) neurons at P10 had an intensely immunoreactive soma, extending relatively long processes with varicosities and/or spines. At P14, PV(+) neurons were located not only in the ISL but also at the border between the ISL and OSL, but in the OSL proper they were rarely observed. These PV(+) neurons showed branched and complicated processes with numerous varicosities and spines, displaying more mature features than those in previous stages. Even at P14 many of these PV(+) neurons appeared to exhibit some characteristic structural features of those in the adult stage.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1983

Correlation of axonal regeneration and slow component B in two branches of a single axon.

We investigated the relationship between slow axonal transport and axonal regeneration in the rat dorsal root ganglion (DRG) cell. The DRG cell sends out a single axon which bifurcates within the ganglion; one axon proceeds centrally into the spinal cord and the other proceeds peripherally. The rate of axonal regeneration is approximately 2 times faster for the peripheral processes (4.6 +/- 0.9 mm/day) than for the central processes (2.1 +/- 0.5 mm/day). The peripheral and central processes regenerate through dissimilar environments (sciatic nerve and dorsal root, respectively); thus, environmental factors may account for the differences in regeneration rates. We tested this possibility by measuring the regeneration of motoneuron axons within the ventral root (histologically similar to the dorsal root). The motoneuron regeneration rate within the ventral root is similar to the motoneuron regeneration rate within the sciatic nerve, suggesting that factors within the DRG cell produce the differences in regeneration rate. Slow axonal transport is classified into two distinct components: slow component a (SCa), corresponding to the microtubule/neurofilament network of the axonal cytoskeleton, and slow component b (SCb), corresponding to the microfilament complex/axoplasmic matrix. The transport rate of SCa and SCb in the peripheral sensory axons is approximately 2 times faster than their counterparts in the central sensory axons. SCa moves at 1.0 to 3.0 mm/day in the peripheral processes and 0.5 to 1.0 mm/day in the central processes; SCb moves at 3.5 to 6.5 mm/day in the peripheral processes and 2.0 to 3.5 mm/day in the central processes. In each branch of the DRG cell, the rate of axonal regeneration is similar to the rate of SCb transport. These results support the hypothesis that SCb is a rate-limiting factor in axonal regeneration because of its role in providing the cytoskeletal elements which are directly involved in the motility of the growth cone and elongation of the axon.

Animals↗
PubMed1984

Mitochondrial motility in axons: membranous organelles may interact with the force generating system through multiple surface binding sites.

In living tissue, membrane-bound organelles, including mitochondria, move along parallel cytoplasmic pathways. Motion is directed and tends to be confined to a single path. Deviations from this single path motion are rare. When present, however, they tend to occur at points of intersection of cytoskeletal linear elements (LE). Such intersections are relatively uncommon in intact axons and extruded axoplasm. However, we have found that such intersections can be produced in extruded preparations by shear forces directed tangential to the axoplasmic surface. We have studied the detailed behavior of mitochondria in extruded squid axoplasm. Special attention was directed to the relationship between mitochondrial shape changes and orientation of cytoskeletal LE. The most striking of these changes in shape is branching. In this process, the mitochondrion transiently assumes a triradial (three-ended) shape. This appearance may be maintained for seconds to minutes before the normal cylindrical shape is resumed by absorption of either the newly formed end or, more commonly, one of the original ends. The frequency of branching appears to be dependent on the degree of cytoskeletal organization. It becomes more common as the number of apparent intersections between cytoskeletal LE increases. Further, the formation of new ends seems to occur along paths defined by cytoskeletal elements. These observations suggest that the mitochondrial membrane is multivalent. That is, it contains multiple sites capable of interacting with the axonal force generation apparatus. Furthermore, LE in the cytoskeleton may indicate the paths along which these interactions are permissible.

Animals↗
PubMed2005

The pathogenesis of clinical depression: stressor- and cytokine-induced alterations of neuroplasticity.

Stressful events promote neurochemical changes that may be involved in the provocation of depressive disorder. In addition to neuroendocrine substrates (e.g. corticotropin releasing hormone, and corticoids) and central neurotransmitters (serotonin and GABA), alterations of neuronal plasticity or even neuronal survival may play a role in depression. Indeed, depression and chronic stressor exposure typically reduce levels of growth factors, including brain-derived neurotrophic factor and anti-apoptotic factors (e.g. bcl-2), as well as impair processes of neuronal branching and neurogenesis. Although such effects may result from elevated corticoids, they may also stem from activation of the inflammatory immune system, particularly the immune signaling cytokines. In fact, several proinflammatory cytokines, such as interleukin-1, tumor necrosis factor-alpha and interferon-gamma, influence neuronal functioning through processes involving apoptosis, excitotoxicity, oxidative stress and metabolic derangement. Support for the involvement of cytokines in depression comes from studies showing their elevation in severe depressive illness and following stressor exposure, and that cytokine immunotherapy (e.g. interferon-alpha) elicited depressive symptoms that were amenable to antidepressant treatment. It is suggested that stressors and cytokines share a common ability to impair neuronal plasticity and at the same time altering neurotransmission, ultimately contributing to depression. Thus, depressive illness may be considered a disorder of neuroplasticity as well as one of neurochemical imbalances, and cytokines may act as mediators of both aspects of this illness.

Animals↗
PubMed2006

Dendritic arbors of developing retinal ganglion cells are stabilized by beta 1-integrins.

The architecture of dendritic arbors is a defining characteristic of neurons and is established through a sequential but overlapping series of events involving process outgrowth and branching, stabilization of the global pattern, and synapse formation. To investigate the roles of cadherins and beta1-integrins in maintaining the global architecture of the arbor, we used membrane permeable peptides and transfection with dominant-negative constructs to disrupt adhesion molecule function in intact chick neural retina at a stage when the architecture of the ganglion cell (RGC) arbor is established but synapse formation is just beginning. Inactivation of beta1-integrins induces rapid dendrite retraction, with loss of dynamic terminal filopodia followed by resorption of major branches. Disruption of N-cadherin-beta-catenin interactions has no effect; however, dendrites do retract following perturbation of the juxtamembrane region of N-cadherin, which disrupts N-cadherin-mediated adhesion and initiates a beta1-integrin inactivating signal. Thus, developing RGC dendritic arbors are stabilized by beta1-integrin-dependent processes.

Amino Acid Sequence↗
PubMed1988

The effect of androgen deprivation on branching morphogenesis in the mouse prostate.

Androgen-induced prostatic development encompasses many individual processes such as ductal branching morphogenesis, cellular proliferation, and secretory cytodifferentiation. Previous studies of ductal morphogenesis (Y. Sugimura, G.R. Cunha, and A.A. Donjacour, 1986, Biol. Reprod. 34, 961-971) demonstrated that the majority (approximately 70%) of ductal tips and branchpoints in the mouse prostate is generated before 15 days of age. Since circulating androgen levels are low during this neonatal period, it is possible that ductal branching morphogenesis may not require the continuous presence of androgens. To test this hypothesis mice were castrated within 24 hr of birth, and prostates from these mice were microdissected at various ages from 5 to 120 days of age to assess the number of ductal tips and branchpoints; wet weight and DNA content were also determined. In intact males wet weight and DNA content increased rapidly between 15 and 60 days of age, after most of the prostatic ductal architecture had been laid down. Neonatal castration considerably reduced the number of tips and branchpoints in both the ventral and dorsolateral prostate, yet both lobes still underwent significant branching morphogenesis in the absence of testes. The administration of anti-androgens to neonatal castrates did not suppress ductal branching to any greater extent than did neonatal castration alone. Androgen replacement immediately following neonatal castration resulted in precocious attainment of the adult number of tips and branchpoints, but caused only modest increases in wet weight. In contrast, when androgen replacement was delayed until adulthood, prostatic wet weight increased to normal adult levels, but the number of ductal tips and branchpoints did not. These experiments show that neonatal prostatic ductal morphogenesis is sensitive to, but does not require, chronic androgen stimulation.

Androgens↗
PubMed1988

The covalent structure of individual N-linked glycopeptides from ovomucoid and asialofetuin.

In order to explore whether individual N-linked glycans in a given glycoprotein may be processed to different end products and at the same time prepare a number of well characterized glycopeptides as substrates for glycopeptide hydrolases, we have prepared the individual glycopeptides representing the four major glycosylation sites in ovomucoid and the three sites in asialofetuin. The individual glycopeptides were characterized by amino acid sequence determination before and after removal of the glycan by peptide:N-glycanase (amidase), and the liberated glycans were subjected to mass spectrometric analysis. As expected from available sugar analyses of the individual glycans in ovomucoid, no major differences were detected between the four glycosylation sites in this glycoprotein, but a definite trend toward less processed (less extensively branched) species was observed in going from site 1 to 4. In fetuin, for which the glycan pool is known to be made up of about two-thirds triantennary and one-third biantennary structures, the analysis of the three glycopeptides gave triantennary to biantennary ratios of 75/25, 67/33, and 70/30, respectively, demonstrating that the three sites are processed to a very similar, albeit perhaps not identical, extent. All the glycopeptides obtained in these studies, including the CNBr-produced glycopeptide from ovalbumin, were purified by a set series of steps, gel filtration on Sephadex G-50 followed by ion-exchange chromatography on DE52 and/or reverse phase high performance liquid chromatography. Based on the results, these procedures appear to have general application for the preparation of glycopeptides.

Amino Acids↗
PubMed1978

Development of adrenergic innervation of the iris and fluorescent ganglion cells in the choroid of the chick eye.

The developing innervation of the chick eye has been studied using catecholamine histofluorescence. The innervation of the pupillary dilator by the superior cervical ganglion begins on day 13 of incubation when fluorescent axons can be seen in the ciliary zone circumscribing the dilator. On day 14 a few processes are seen to branch from this band into the dilator. The number of processes in the dilator increases on days 15 and 16. After day 16 there is a reorganization of the fibers radially accompanied by a moderate increase in the number of processes. In addition, a group of fluorescent cells can be seen in the choroid adjacent to the ciliary body. These cells are bipolar at day 9 and become multipolar by 12 days of incubation. These cells contribute to a fluorescent plexus of processes in the choroid which stops abruptly at the border of the choroid and ciliary zone. It is thought that they represent a terminal sympathetic ganglion receiving preganglionic input from the carotid nerve.

Animals↗
PubMed1986

Structure of the olfactory bulb of the hedgehog (Erinaceus europaeus): description of cell types in the granular layer.

The cytoarchitecture of the olfactory bulb and the cell types in the granular layer of adult hedgehogs have been studied with the Golgi method. The mitral cell layer does not stand out as a monolayer as in most mammals; it is arranged as a diffuse stratum with mitral cells displaced into the external plexiform layer. The external plexiform layer is exceedingly thick and contains the branches of peripheral processes of granule cells and displaced mitral and tufted cells. The granular layer contains granule cells and varieties of short-axon cells. Among granule cells a type of cell with an elaborate system of protrusions close to the cell body has been found. Four main varieties of short-axon cells are described. These include cells with local or extended axons, according to the branching pattern of their axons inside the granular layer or extending into the external plexiform layer as well. Short-axon cells were also classified as cells with smooth and spinous dendrites. A variety of cell with smooth dendrites and elaborate axonal system reaching the periglomerular zone is described. This type of cell has been found frequently in the olfactory bulb of the hedgehog. In comparison to several other mammals, short-axon cells in the olfactory bulb of the hedgehog have been found to be particularly abundant and to have more complex axonal systems. It is suggested that some of them may represent inhibitory interneurons acting upon granule and periglomerular cells, playing an important role in the centrifugal pathway controlling the olfactory input.

Animals↗
PubMed1999

Fractal Approach to Adsorption Isotherms of Water Vapor on Active Carbons.

Adsorption isotherms of water vapor on active carbons are interpreted in terms of the fractal approach. The linear range of plots in the steep rise of the adsorption branch is the process of the cluster formation of water on the seed water molecules adsorbed on the primary adsorption centers, mainly the oxygen-surface complexes, with the fractal dimension D = 1.64-1.67 which is equivalent to that for the diffusion-limited aggregation (DLA) model with D approximately 1.66. Also, it is shown that the two-dimensional characteristics of micropore structures are reflected in the adsorption branch and the three-dimensional ones are in the desorption branch, respectively, by the analyses of the D and the average micropore width L based on the characteristic adsorption amounts at the beginning and the ending points of the steeply rising and falling linear ranges on both branches. Copyright 1999 Academic Press.

Journal Article↗
PubMed1989

The twitcher mouse: attenuated processes of Schwann cells in unmyelinated fibers.

Morphological alterations occurring in Schwann cells of unmyelinated fibers (unmyelinated Schwann cells) were investigated in the sciatic nerve of the twicher mouse, a murine model of human globoid cell leukodystrophy. After postnatal day 10, the number of Schwann cell-axon units gradually increased and the number of unmyelinated axons per unit progressively decreased in the twitcher mouse. However, the total number of unmyelinated axons showed no significant differences between twitcher and normal mice. Thus, these alterations of unmyelinated Schwann cells in the twitcher mouse suggest that attenuated branching of cellular processes develops at an early stage and progresses together with progression of demyelination in this mutant.

Animals↗
PubMed2006

Wnt signaling establishes anteroposterior neuronal polarity and requires retromer in C. elegans.

Secreted Wnt proteins influence neural connectivity by regulating axon guidance, dendritic morphogenesis and synapse formation. We report a new role for Wnt and Frizzled proteins in establishing the anteroposterior polarity of the mechanosensory neurons ALM and PLM in C. elegans. Disruption of Wnt signaling leads to a complete inversion of ALM and PLM polarity: the anterior process adopts the length, branching pattern and synaptic properties of the wild-type posterior process, and vice versa. Different but overlapping sets of Wnt proteins regulate neuronal polarity in different body regions. Wnts act directly on PLM via the Frizzled LIN-17. In addition, we show that they are needed for axon branching and anteriorly directed axon growth. We also find that the retromer, a conserved protein complex that mediates transcytosis and endosome-to-Golgi protein trafficking, plays a key role in Wnt signaling. Deletion mutations of retromer subunits cause ALM and PLM polarity, and other Wnt-related defects. We show that retromer protein VPS-35 is required in Wnt-expressing cells and propose that retromer activity is needed to generate a fully active Wnt signal.

Animals↗
PubMed1994

Development of specificity in corticospinal connections by axon collaterals branching selectively into appropriate spinal targets.

Corticospinal projections in adult rodents arise exclusively from layer V neurons in the sensorimotor cortex. These neurons are topographically organized in their connections to spinal cord targets. Previous studies in rodents have shown that the mature distribution pattern of corticospinal neurons develops during the first 2 weeks postnatal from an initial widespread pattern that includes the visual cortex to a distribution restricted to the sensorimotor cortex. To determine whether specificity in corticospinal connections also emerges from an initially diffuse set of projections, we have studied the outgrowth of corticospinal axons and the formation of terminal arbors in developing hamsters. The sensitive fluorescent tracer 1,1',dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate (DiI) was used to label corticospinal axons from the visual cortex or from small regions of the forelimb or hindlimb sensorimotor cortex in living animals at 4-17 days postnatal. Initially axon outgrowth was imprecise. Some visual cortical axons extended transiently beyond their permanent targets in the pontine nuclei, by growing through the pyramidal decussation and in some cases extending as far caudally as the lumbar enlargement. Forelimb sensorimotor axons also extended past their targets in the cervical enlargement, in many cases growing in the corticospinal tract to lumbar levels of the cord. By about 17 days postnatal these misdirected axons or axon segments were withdrawn from the tract. Despite these errors in axon trajectories within the corticospinal tract, terminal arbors branching into targets in the spinal gray matter were topographically appropriate from the earliest stages of innervation. Thus visual cortical axons never formed connections in the spinal cord, forelimb sensorimotor axons arborized only in the cervical enlargement, and hindlimb cortical axons terminated only in the lumbar cord at all stages of development examined. Corticospinal arbors formed from collaterals that extended at right angles from the shafts of primary axons, most likely by the process of interstitial branching after the primary growth cone had extended past the target. Once collaterals extended into the spinal gray matter, highly branched terminal arbors formed within 2-4 days, beginning at about 4 and 8 days postnatal for the cervical and lumbar enlargements, respectively. These results show that specificity in corticospinal connectivity is achieved by selective growth of axon collaterals into appropriate spinal targets from the beginning and not by the later remodeling of initially diffuse connections. In contrast, errors occur in the initial outgrowth of axons in the corticospinal tract, which are subsequently corrected.

Animals↗
PubMed1984

Langerhans cells in squamous exocervical carcinoma: a quantitative and ultrastructural study.

The gross morphology, density, distribution, and ultrastructure of the Langerhans cell (LC) in the human exocervix in cases of cervical intraepithelial neoplasia (CIN) and incipient carcinoma were investigated. Two zinc-iodide-osmium (ZIO) procedures were applied to epithelial sheets and to tissue sections for light and electron microscopy. The ZIO methods as well as conventional electron microscopy revealed the presence of LCs in CIN, in the invasive prongs, and in the lymphoid infiltrate of the chorion. The epithelial sheets demonstrated a LC density 3.5 times higher than we have previously reported for the normal exocervix. The region around the external os displayed the highest LC density and the most advanced grades of CIN. The LCs were classified into six types according to the number of processes and secondary branches. The most ramified types were more abundant in the neoplastic exocervix than in the normal exocervix. The LC in all locations of the exocervix with carcinoma showed hypertrophy of the rough and smooth endoplasmic reticula and a large number of filaments. The RER displayed dilated cisternae containing electron-dense material. Specialized contacts between LCs and lymphocytes were an outstanding finding. These findings suggest that the LC might play an important role in the neoplastic process.

Adult↗
PubMedDate not supplied

Morphological analysis and modeling of neuronal dendrites.

Morphological data on two classes of neurons from mammalian midbrain have quantitatively been analyzed for dendritic shape parameters. Their frequency distributions were used to optimize the parameters of a dendritic growth model which describes dendritic morphology by a stochastic growth process of segment branching. The model assumes randomness with respect to both the selection of the branching segment out of the tree segments and the occurrence of the branching event in time. Model-generated trees have shape properties closely matching the observed ones. The dendritic trees of each of the two classes of neurons are represented by a specific set of growth model parameters, thus achieving morphological data compression.

Animals↗