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  • Cell & Developmental Biology  (5)
  • Unit recording  (3)
  • ethylene  (3)
  • 1
    Digitale Medien
    Digitale Medien
    Springer
    Experimental brain research 17 (1973), S. 315-332 
    ISSN: 1432-1106
    Schlagwort(e): Red nucleus ; Unit recording ; Motor cortex ; Topographical organization ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary A topographical study of the cortico-rubrospinal pathway was conducted in cats anesthetized with chloralose. Extracellular unit recordings were made from cells in the red nucleus projecting to the spinal cord. They were identified by antidromic invasion following stimulation of their axones at the 2nd cervical and 9th thoracic levels of the spinal cord. I. The pericruciate cortical regions from which spikes could be induced in rubrospinal neurons were limited to the lateral part of the anterior sigmoid gyrus, the lateral sigmoid gyrus and the anterior part of the posterior sigmoid gyrus. No responses were obtained from stimulation of the medial part of the anterior sigmoid gyrus or the gyrus proreus. Compared to the somatotopic organization of the motor cortex for the cat described by Woolsey (1958), our results show that the rubrospinal cells receive projections from the motor cortex controlling proximal and distal muscles but not axial muscles. II. Neurons projecting to the cervico-thoracic cord receive afferents from the lateral part of the anterior sigmoid gyrus and the lateral sigmoid gyrus whereas those projecting to the lumbo-sacral cord receive projections from the entire surface of the sigmoid gyrus except the medial part of the anterior sigmoid gyrus and the gyrus proreus. III. A latero-medial organization of cells within the red nucleus was found according to the origin of their cortical afferents. Rubrospinal neurons with fibers terminating in the cervical or thoracic cord receive projections from the motor cortex controlling the proximal musculature of the forelimb when they are located in the dorso-lateral region of the nucleus and the entire forelimb motor cortex when they are located in the medial part of the nucleus. It is suggested that this organization may indicate a control of proximal forelimb musculature by dorsolateral rubrospinal cells and distal musculature by medial cells. IV. Rubrospinal cells placed medially in the nucleus receive more convergent projections (i.e. from a greater cortical surface) than cells placed more laterally. It was shown that for certain cells the convergence occurs in the direct pathway. These results are discussed in terms of a functional organization allowing coordinated movements of different segments of a single limb or of different limbs.
    Materialart: Digitale Medien
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  • 2
    Digitale Medien
    Digitale Medien
    Springer
    Experimental brain research 14 (1972), S. 363-371 
    ISSN: 1432-1106
    Schlagwort(e): Rubrospinal cells ; Unit recording ; Topographical organization ; Conduction velocity
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Mapping of cells at the origin of the rubrospinal tract was conducted in the cat. 1. Rubrospinal neurons sending efferents to cervico-thoracic segments of the spinal cord are located in the dorso-medial part of the nucleus. These neurons are especially medial in the caudal planes and especially dorsal in the rostral planes. Neurons with efferents terminating at the level of lumbo-sacral segments of the cord occupy the ventro-lateral part of the nucleus. These neurons are especially lateral in the caudal planes and especially ventral in the rostral planes. The limit between these two cell populations is clear in the caudal and middle thirds of the nucleus but considerable overlap is seen in the rostral third. These results agree with the anatomical findings of Pompeiano and Brodal (1957). 2. For the population of lumbar neurons the conduction velocities ranged from 31 m/sec to more than 120 m/sec with a mean of 85 m/sec. 3. Rubrospinal cells are found throughout the nucleus. The most caudal planes are essentially composed of cells with rapidly conducting fibers whereas in the middle and rostral planes a cell population with increasingly slower conducting fibers appears. The results of the present study are discussed in relation to classical data on the magnocellular and parvocellular divisions of the red nucleus. 2.The third author acknowledge the personal support of the Medical Research Council of Canada.
    Materialart: Digitale Medien
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  • 3
    ISSN: 1432-1106
    Schlagwort(e): Precentral motor cortex ; Unit recording ; Isometric precision grip ; Force and rate of force change ; Microstimulation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The activity of single neurons within the hand area of the precentral motor cortex of primates was recorded during the performance of a maintained precision grip between the thumb and forefinger. The finger opposition forces were exerted against a strain gauge which allowed force changes to be studied under near isometric conditions. Task performance required the generation of a force ramp (the dynamic phase) and thereafter the maintenance of a stable force for one second (the static phase). Intracortical stimulation through the recording electrode was used to verify that the recordings were made from the appropriate somatotopographic area of the motor cortex. From a total of 221 recorded neurons, 76 were found to be either activated or deactivated during performance of the task. Among the 51 activated neurons, most discharged at higher frequencies during the dynamic phase, than during the static phase. The discharge of some of these neurons could be related to both force (F) and rate of force change (df/dt) whereas certain others could only be correlated with df/dt. The change in discharge frequency for these neurons generally occurred prior to the onset of EMG activity. Eight neurons were more active during maintained force than during the force ramp. The discharge frequency could not be correlated with df/dt and only one showed a significant positive relation to force. The change in discharge frequency for these neurons either coincided or occurred after the onset of EMG activity.
    Materialart: Digitale Medien
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  • 4
    ISSN: 1573-5087
    Schlagwort(e): Arabidopsis ; EBP ; ethylene ; phosphorylation ; receptors ; signal transduction
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Previous work in our laboratory has demonstrated the existence of high affinity binding sites for the plant growth regulator ethylene. The ethylene binding protein (EBP), from Phaseolus cotyledons, shows many of the characteristics of a functional receptor for ethylene, has been purified on SDS-PAGE and polyclonal antibodies raised in rabbits. Current work involves the investigation of the ethylene transduction signal in a number of ethylene-responsive tissues. In peas, it has been shown that ethylene promotes the phosphorylation of specific proteins of similar molecular weight to the EBP from Phaseolus. Such ethylene-induced phosphorylation can be inhibited by the ethylene antagonist, 2,5-NBD. The antibodies raised to the EBP from Phaseolus have been shown to immunoprecipitate 32P-labelled proteins from membrane protein preparations obtained from pea tissue. Studies on ethylene binding in pea have also shown that the binding of ethylene may be regulated by phosphorylation. Thus, under conditions which promote phosphorylation, binding is inhibited, whereas the reverse is true under conditions which enhance dephosphorylation. Further work is described which examines the effect of protein kinase, protein phosphatase and calcium channel inhibitors on ethylene-induced phosphorylation in peas, together with wild-type (WT) and ethylene insensitive (eti) mutants of Arabidopsis thaliana. The effects of these treatments can be monitored in vivo using the ethylene-induced triple response as a screen. Furthermore, the protein profiles of such treated seedlings can then be compared by labelling protein extracts with 32P and subjecting the samples to SDS-PAGE followed by autoradiography.
    Materialart: Digitale Medien
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  • 5
    Digitale Medien
    Digitale Medien
    Springer
    Plant growth regulation 1 (1982), S. 203-207 
    ISSN: 1573-5087
    Schlagwort(e): Vicia faba ; ethylene ; ethylene oxide ; waterlogging ; metabolism
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract The ability of cultivars of Vicia faba L. to metabolize ethylene and the resistance of such cultivars to waterlogging was assessed. Those cultivars showing the highest resistance to waterlogging also had the ability to rapidly metabolize ethylene. It is suggested that a causal relationship may exist between the two processes.
    Materialart: Digitale Medien
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  • 6
    Digitale Medien
    Digitale Medien
    Springer
    Plant growth regulation 18 (1996), S. 71-77 
    ISSN: 1573-5087
    Schlagwort(e): Arabidopsis ; ethylene ; ethylene binding protein ; signal transduction
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract A review of work carried out on ethylene binding in higher plants is presented. The use of radio-labelled displacement assays has identified specific 14C-ethylene binding in all tissues so far studied. virtually all higher plants studied contain at least two classes of ethylene binding site, one of which fully associates and dissociates in about 2 h and a class of sites that takes up to 20 h to become fully saturated. Although the types of site differ in their rate constants of association they have similar and high affinities for ethylene. A series of Arabidopsis thaliana mutants shown to vary in sensitivity to ethylene have been analysed for 14C-ethylene binding. One mutant, eti 5, which was shown to be unaffected by ethylene concentrations of up to 10,000 μL L−1 was also shown to exhibit reduced binding. In vivo and in vitro studies on pea have shown that ethylene binding can be detected in this tissue. In vitro studies have shown that both membrane and cytosolic fractions contain measurable amounts of ethylene binding. Interestingly, cytosolic ethylene binding consisted only of the fast associating/dissociating type. Developing cotyledons of Phaseolus vulgaris contain a higher concentration of ethylene binding sites that other tissues and only contain the slow dissociating component. These facets have allowed the purification of ethylene binding protein(s) (EBP) from this tissue. The proteins which bind ethylene can be resolved into two bands of 26 and 28 kDa on semi-denaturing PAGE and the proteins appear to be single entities on a 2-D gels. Data will be presented which indicate a possible role for heterotrimetric G-proteins in the early stages of the ethylene signal transduction pathway.
    Materialart: Digitale Medien
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  • 7
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 36 (1993), S. 331-337 
    ISSN: 1040-452X
    Schlagwort(e): Ovulation ; Meiotic maturation ; Vixens ; Polar fox ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: A total of 15 blue fox vixens aged 1-6 years were mated, 12 once on the first day of estrus and three a second time 48 hr after the first mating, and were killed 4 hr to 8 days following mating. Ova were collected from the oviducts, evaluated by stereomicroscopy, and studied by transmission (TEM; N = 49, 12 vixens) or scanning (SEM, N = 11, three vixens) electron microscopy. At 0-3 days after ovulation, the ova had not cleaved and were at different stages of meiotic maturation. In about one-half of these ova, representing all stages of meiotic maturation, a decondensing sperm head without nuclear envelope or a small pronucleus with partial nuclear envelope was observed. No clear relationship was found between maternal meiotic stage and the stage of paternal pronucleus formation. Sperm tails were never identified in the ooplasm. Cortical granules were released after sperm penetration at early stages of meiotic maturation. Thus the block against polyspermic penetration was activated during maturation of the oocyte. The first two-cell stage appeared 4 days after ovulation (3 days after mating), the first four-cell stage the following day (day 5), and the first eight-cell stage 6 days after ovulation (5 days after mating). In a single vixen mated late (7 days postovulation) two- to four-cell stages appeared the following day (day 8). This indicates that the time required for the first cleavage division decreases with increasing interval from ovulation to mating. The development of a functional nucleolus with fibrillar centers and fibrillar and granular components at the eight-cell stage indicates activation of embryonic RNA synthesis in fox embryos at the six- to eight-cell stage, suggesting that the embryonic genome is activated at this stage. © 1993 Wiley-Liss, Inc.
    Zusätzliches Material: 13 Ill.
    Materialart: Digitale Medien
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  • 8
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 95 (1978), S. 287-294 
    ISSN: 0021-9541
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The potent tumor promoter tetradecanoyl phorbol acetate (TPA) induces early changes in ion movements analogous to those induced by prostaglandins E1 and F2α. Among the earliest changes induced by TPA is a significant increase in 32Pi incorporation within 15 minutes incubation of TPA (10-8-10-6 M) with post-confluent Swiss 3T3 mouse embryonic fibroblasts. Similarly, the active phorbol ester homolog 4-;β-;OH phorbol didecanoate but not the inactive stereoisomeric 4-β-OH phorbol didecanoate stimulated 32Pi incorporation. Also, TPA at the above concentrations stimulated 86Rb+ influx shortly after administration. Both fluxes were ouabain-sensitive in accord with the idea that an early effect of TPA is to alter (Na+ + K+)-ATPase activity. Further, prostaglandin E1 (10-7-10-6 M) and prostaglandin F2α (3 × 10-9-10-7 M) caused a similar stimulation of 86Rb+ and 32Pi uptake. The finding that water-soluble prostaglandin F2α also exhibited stimulatory effects indicated that those hormone-induced responses are not mediated by solvent interactions. The similar responses of phorbol esters and prostaglandin derivatives suggests that phorbol esters and prostaglandin derivatives may act at common membrane sitesThe finding that stimulatory effects were observed at discrete times in the logarithmic phase of growth suggests that the activation of membrane receptors may be cell-cycle dependent.
    Zusätzliches Material: 9 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 9
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 167 (1970), S. 351-369 
    ISSN: 0003-276X
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: A light and electron microscopy study of the structure of the pronephros of the carp, Cyprinus carpio, revealed lymphocytopoiesis, plasmacytopoiesis and erythrocytopoiesis. In addition to the lymphocytes of various sizes, there were transitional cells which had characteristics of both lymphocytes and plasma cells. Some of the plasmacytoid cells had a configuration of cytoplasmic granules suggestive of the Russell body formation described in higher mammalian forms. When India ink particles were injected into the fish intraperitoneally, macrophages containing this marker could be found in the pronephros. The highly vascular structure of this organ emphasized the close association of the cellular elements with the circulating blood. In view of the cell population of the pronephros and its role as a major source of cells producing antibody, it may well represent a primitive prototype of the more advanced mammalian lymph node.
    Materialart: Digitale Medien
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  • 10
    ISSN: 0730-2312
    Schlagwort(e): giant cell tumor of bone ; MCP-1 ; TGF-β ; CD68+ ; chemotaxis ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Chemie und Pharmazie , Medizin
    Notizen: Giant cell tumor of bone (GCT) is one of a few neoplasms in which the macrophage/osteoclast precursor cells and osteoclast-like giant cells infiltrate the tumor mass. Monocyte chemoattractant protein 1 (MCP-1) is a potent chemotactic factor specific for monocytes. In search of relevant cytokines that may enhance the recruitment of these reactive cells, we evaluated the localization and regulation of MCP-1 mRNA and protein in GCT by using Northern blot analysis, in situ hybridization and immunohistochemistry. We also determined whether conditioned medium obtained from GCT cultures can recruit human peripheral blood monocytes (CD68+) in an in vitro chemotactic assay. Using Northern blot analysis, we detected the specific gene transcript for MCP-1 in all GCT samples tested. In situ hybridization and immunohistochemistry revealed that both MCP-1 gene transcript and protein were consistently present in the cytoplasm of stromal-like tumor cells of GCT. Treatment of mononuclear cells from GCT at third passage with TGF-β1 for 24 h increased the level of MCP-1 mRNA in a dose-dependent manner, with the maximum effect at 1 ng/ml. Conditioned media from GCT cultures promoted the chemotactic migration of CD68+ peripheral monocytes, an activity which was abolished by the addition of MCP-1 antibody to the conditioned medium. Thus, the results of this study suggest that recruitment of CD68+ macrophage-like cells may be due to the production MCP-1 by stromal-like tumor cells. These CD68+ cells may originate from peripheral blood and could have the capability of further differentiating into osteoclasts in the tumor. J. Cell. Biochem. 70:121-129, 1998. © 1998 Wiley-Liss, Inc.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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