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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 162 (1975), S. 209-233 
    ISSN: 1432-0878
    Keywords: Sympathetic neurons ; Frog ; Nerve growth factor ; Accessory cells ; Tissue culture
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary 1. A culture medium has been developed for amphibian sympathetic nervous tissue but it is suggested that the ionic values should be adjusted to correspond to the concentrations of salts in the plasma of particular species. 2. The morphology, monoamine fluorescence, growth and differentiation of sympathetic ganglia of the frog, Limnodynastes dumerili, have been studied in culture. 3. Two types of neuron could be distinguished largely according to size, namely small, 18×20 μm and large, 38×42 μm. The possibility that these represent one type at different stages in development or represent functionally distinct neurons is discussed. 4. The sympathetic neurons are extremely sensitive to nerve growth factor (NGF) which caused an increase in the size of the cell bodies, the number of nerve fibres regenerating, the rate of axonal growth and synthesis of catecholamines. 5. Various other cell types appearing in the cultures have been described, including chromaffin, satellite, Schwann, multipolar and epithelial cells as well as fibroblasts, melanocytes and macrophages. The epithelial cells show slow contractions and changes in shape.
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  • 2
    ISSN: 1573-6865
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Synopsis It is known that hydrocortisone causes a great increase in the number of small intensely fluorescent (SIF) cells in the sympathetic ganglia when injected into newborn rats. The effect of hydrocortisone on nervous tissuein vitro has not been studied previously. Pieces of newborn rat sympathetic ganglia were cultivated in Rose chambers. Hydrocortisone was dissolved in the medium in concentrations of 1–9 mg/l. Both control and hydrocortisone-containing cultures were examined daily by phase-contrast microscopy, and the catecholamines were demonstrated histochemically by formaldehyde-induced fluorescence after 7 days in culture. All cultures showed outgrowths of axons and supporting cells elements, although these were less extensive in the groups of cultures with hydrocortisone. After a week, SIF cells with a green fluorescence were observed in the control explants. In all cultures with hydrocortisone, a concentration-dependent increase was observed in the fluorescence intensity and the number of the SIF cells in the explant; numerous SIF cells were also seen in the outgrowth. Some SIF cells showed processes and the longest processes were seen in cultures with the highest concentration of hydrocortisone. It is concluded that hydrocortisone causes an increased synthesis of catecholamines in the SIF cellsin vitro, and an increase in their number by affecting either their division or their differentiation from a more immature form, or both. This effect was a direct one and not mediated by any system other than the ganglion itself. Induction of enzyme synthesis by hydrocortisone is proposed as an explanation of the increase in catecholamine concentration.
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  • 3
    ISSN: 1572-9486
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The need for highly charged heavy ions from projected particle accelerators has recently led to a re-evaluation of the complex processes of ion production in laser generated plasmas. Possible mechanisms for the production of intense beams of high charge state ions are investigated as is the experimental evidence for these mechanisms. The hypothesis that 20 keV ions are driven by “hot electrons” is not supported by experimental work to date. This work, on the other hand, suggests that 30ps pulsation is the basic mechanism for the acceleration of tantalum ions up to charge state 8+ whose energy increases linearly with charge state up to 24keV. For long pulses and charge states between 8+ and 18+, it appears that there is a secondary mechanism of electron impact ionisation by plasma electrons of approximately 200 eV in the plasma in front of the target, resulting in ions whose energy of around 24 keV is independent of charge state.
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  • 4
    ISSN: 1572-9540
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The motivation of using electron cooling in low-energy antiproton storage rings and the expected cooling performance are discussed. Results obtained recently, during the first operation of electron cooling in LEAR at CERN with a 50 MeV proton beam, are summarized, concerning in particular the equilibrium beam properties, the recombination between cooling electrons and cooled protons, and the deceleartion of acceleration of protons by friction in the electron beam. Conclusions are drawn for the formation of antihydrogen with the cooled antiproton beam, and for the deceleration of antiprotons to energies close to or below 1 MeV.
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  • 5
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: The CERN heavy ion community, and some other high energy physics experiments, are starting to demand other ions, both heavy and light, in addition to the traditional lead ions. Studies of the behavior of the afterglow for different operation modes of the ECR4 at CERN have been continued to try to understand the differences between pulsed afterglow and continuous operation, and their effect on ion yield and beam reproducibility. The progress in adapting the source and ion beam characteristics to meet the new demands will be presented, as will new information on voltage holding problems in the extraction. © 2002 American Institute of Physics.
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  • 6
    ISSN: 1432-1424
    Keywords: Whole cell ; Single channel ; Cesium ; Liver ; Resting potential
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The single channel and whole-cell properties of an inward, rectifying potassium current in cultured embryonic chick hepatocytes were studied at 20°C. In cell-attached patches, channels open upon membrane hyperpolarization and are present in about 90% of cellattached patches. With 145 mm potassium in the pipette, inward current has a slope conductance of 80 pS. The conductance is not a linear function of the external potassium concentration. Current saturates at high external potassium and has a Michaelis-Menten affinity constant of 275 mm potassium. Substitution of gluconate for chloride in the external solution has no significant effect on conductance, and the reversal potential shifts approximately 18 mV with a change in external potassium from 72.5 to 145 mm indicating potassium selectivity. Channel openings are characterized by multiple brief closures during a burst. The channel is inhibited by external cesium in a concentration-dependent manner. Block is characterized by an increased frequency of transient closures. Whole-cell dialysis with 145 mm CsCl of cells bathed in 145 mm KCl reveals time-independent inward currents that reverse at 0 mV in response to 200 msecvoltage steps. Although voltage ramps evoke currents that are 75% potassium dependent and cesium sensitive, the mean chord conductance (425 pS) indicates that less than five channels are open at any instant. We suggest that the inwardly rectifying potassium channel is partially inactivated in the dialysed hepatocyte.
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  • 7
    ISSN: 1432-0878
    Keywords: Frog ; Chromaffin ; Classification ; Nerve endings ; Fluorescence microscopy ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary 1. The distribution and morphology of chromaffin cells in the para-aortic region and in the ganglia of the paravertebral sympathetic chain was studied with fluorescence histochemistry and electron microscopy. 2. Four types of chromaffin cell were distinguished largely on the basis of their vesicular content: Type I cells contain large, electron-dense vesicles (600–7000 Å) and are comparable to noradrenaline-containing cells in the adrenal gland, Type II cells contain large, vesicles (600–7000 Å) that are filled with a less electron-dense material than that in Type I cells and are comparable to adrenaline-containing cells in the adrenal gland, Type III cells contain smaller vesicles (1000–3000 Å) that are incompletely filled with an electron-dense material and may represent cells that have been depleted of their catecholamines by stimulation, Type IV cells are clearly different from the other three cell types with respect to the size and appearance of the vesicles (1000–1500 Å), nuclei and rough endoplasmic reticulum and may represent immature sympathetic neurons. 3. Nerve profiles, identified as cholinergic, were found in close apposition with all four cell types. No examples of a close association between processes of chromaffin cells and sympathetic neurons were found.
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 161 (1975), S. 103-117 
    ISSN: 1432-0878
    Keywords: Tissue culture ; Chromaffin cells ; Frog ; Classification ; Phase contrast microscopy ; Fluorescence microscopy ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary 1. Extra-adrenal chromaffin cells from adult frogs were grown in tissue culture and their morphology and behaviour observed with both light and electron microscopy. 2. Two types of chromaffin cells were distinguished: Type A cells contain large, electron dense vesicles (2000–6000 Å) and are equated to Type I chromaffin cells seen in vivo, i.e. they contain noradrenaline; Type B cells contain smaller vesicles (700–2000 Å) which are incompletely filled with an electron dense material and are equated to Type III chromaffin cells seen in vivo, i.e. cells depleted of their catecholamines by stimulation. No cells comparable to Types II and IV cells in vivo were seen. 3. Close associations between the cultured chromaffin cells and sympathetic neurons were observed with the light microscope, but no examples of synaptic structures were seen in the material examined with electron microscopy in this study.
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  • 9
    ISSN: 1432-0878
    Keywords: Key words Neurotransmitter receptor ; Antibody ; Sympathetic nervous system ; Alpha-adrenergic receptor ; Iris ; Reverse transcription/polymerase chain reaction ; Rat (Wistar-Kyoto)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract  Expression of the α1B-adrenergic receptor was investigated immunohistochemically in the rat iris, cornea and superior cervical ganglion by using antibodies raised in chickens immunised with a peptide corresponding to a portion of the 3rd intracellular loop common to the human, hamster and rat α1B-adrenergic receptor. Antibodies stained COS and HEK cell membranes of cells transfected with DNA encoding and expressing the hamster α1B-adrenergic receptor but not membranes from cells transfected with DNA encoding and expressing the rat α1A-adrenergic receptor or the rat α1D-adrenergic receptor. Staining was abolished by preincubation of the antibodies with the peptide used for immunisation. The distribution of α1B-adrenergic receptor was examined immunohistochemically with this antibody (1BI3) and a previously characterised antibody (Ab506) raised in rabbits against the carboxyl-terminal decapeptide of the receptor. In the iris, α1B-adrenergic receptor was detected in the dilator muscle, ciliary processes and posterior epithelium but no staining was observed in the superior cervical ganglion with either antibody. By contrast, differences in tissue staining between 1BI3 and Ab506 were observed for the sphincter muscle of the iris and for the cornea. 1BI3 stained both tissues intensely, whereas Ab506 only stained the cornea weakly and the sphincter not at all. Reverse transcription/polymerase chain reaction and nucleotide sequencing confirmed the presence of mRNA encoding the epitopes recognised by 1BI3 and Ab506 in cornea and other tissues. We conclude that (1) there is a good correlation between α1B-adrenergic receptor mRNA and protein expression in the iris, (2) mRNA, but not protein, is detected in the superior cervical ganglion and (3) additional processes may regulate receptor expression in the cornea.
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  • 10
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 287 (1980), S. 647-649 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] The iris, ciliary body and choroid were dissected aseptically from 19-day-old chicken embryos, and material from one eye placed in 2 ml of Eagle's medium containing Hanks salts, 50 mM HEPES and 100 U ml"1 penicillin, and incubated at 37 C in humid air. The ability of the conditioned medium to ...
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