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  • 1
    Electronic Resource
    Electronic Resource
    Neural differentiation in the OTT-6050 mouse teratoma (1981)
    Springer
    Virchows Archiv 392 (1981), S. 281-294 
    Details
    ISSN: 1432-2307
    Keywords: Mouse teratoma ; Centrifugal elutriation ; Neuroepithelial enrichment
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Dissociation and centrifugal elutriation procedures were applied to subcutaneous transplants of the OTT-6050 mouse teratoma line in order to enrich the neuroepithelial cells. One of the resultant cell fractions, designated IB-21, was then implanted beneath the renal capsule of syngeneic mice and rebanked every 3 to 6 weeks for a total of 58 passages over 5 years. Sequential passages resulted in a tumor restricted to stem cells and neural cells (neuroblasts and glial cells). The primitive neural cells lost the ability to form rosettes after the early transplants. Subcutaneous or intracerebral transplantation of these tumors evinced their capacity for further neuroepithelial differentiation, with the demonstration of astrocytes and occasional mature synapse-forming neurons. Conversion of the tumor to the ascitic form resulted in unorganized clusters of neoplastic cells in contrast to the highly structured embryoid bodies that are characteristic of the parent OTT-6050 line. The absence of non-neural cells in the IB-21 tumor fraction and its ability to demonstrate divergent neural differentiation suggest that a transplantable neural-determined cell population exists in the OTT-6050 mouse teratoma.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02155666
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  • 2
    Electronic Resource
    Electronic Resource
    Neural differentiation in the OTT-6050 mouse teratoma (1981)
    Springer
    Virchows Archiv 392 (1981), S. 295-308 
    Details
    ISSN: 1432-2307
    Keywords: Mouse teratoma ; Centrifugal elutriation ; Melanotic neuroepithelium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Dissociation and elutriation procedures were applied to the OTT-6050 mouse teratoma line carried in subcutaneous implants in 129/J mice in order to enrich the differentiating neuroepithelial cells. Subsequent renal subcapsular implantation of one of the resultant cell fractions (IB-9) in syngeneic mice led to the constant production of macroscopically pigmented tumors which, in addition to undifferentiated stem cells, contained primitive neuroepithelial populations composed of medullary epithelium, neuroblasts, and numerous ependymoblastic rosettes. Melanin pigment, confirmed by the presence of melanosomes and premelanosomes, was found in medullary epithelium and other primitive neural cells. The tumors preserved their characteristics through 65 sequential transplants over a period of 5 1/3 years. The pigment was maintained in vitro for up to 3 months in an organ culture system. Subcutaneous or intracerebral transplantation of the renal tumors of the IB-9 fraction accentuated the capacity of these primitive cells towards further neuroepithelial differentiation into mature synapse-forming neurons, and was associated with a decrease in primitive neuroepithelium and an absence or a marked decrease of melanin. Return of the tumor to the kidney resulted in the reappearance of melanin after one to three passages, again associated with the presence of primitive neuroepithelium. The recognition of melanin pigment in the OTT-6050 mouse teratoma transplants could be a useful marker for the successful selection of primitive neuroepithelial cell populations in this experimental tumor system. These populations may help to study the relationship between melanin production and certain types of primitive neuroectodermal tumors in man.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02155667
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  • 3
    Electronic Resource
    Electronic Resource
    Neural differentiation in the OTT-6050 mouse teratoma: Effects of intracerebral environment on the neural differentiation of embryoid bodies (1981)
    Springer
    Virchows Archiv 393 (1981), S. 39-52 
    Details
    ISSN: 1432-2307
    Keywords: Mouse teratoma ; Embryoid bodies ; Cerebral transplantion ; Neural differentiation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Small embryoid bodies (EB's) from the OTT-6050 transplantable mouse teratoma, obtained by gravity filtration through a 74 μ mesh, were injected into the right cerebral hemisphere of syngeneic newborn or adult mice of both sexes in order to produce differentiating teratomas after a single passage. In subsequent experiments, two solid tumors resulting from two different EB-implants into the brains of adult hosts were used to initiate sequential tumors and were carried intracerebrally in adult mice for 12 and 18 passages respectively. The animals were sacrificed when signs of increased intracranial pressure developed. Survival times were as follows: single passages in adult mice: mean, 35 days; single passages in neonatal mice: mean, 19 days; sequential passages in adult mice: mean, 25 days. Multipotential stem cells accounted for l/2 to 3/4 of the cens in all tumors. Primitive neural cells, ependymoblastic rosettes, neuroblasts and glia were present in all; stem cells, primitive neural cells and rosettes decreased proportionately as the more differentiated neural populations became prominent. Mature ganglion cells were found only in the sequentially passaged tumors and in tumors maintained for more than one month after a single passage in adult mice. Synapses were noted in the most differentiated areas. Neuroblasts were infrequent in tumors developing in neonatal hosts, and mature ganglion cells were absent. Glial fibrillary acidic protein was present by the 24th day in tumors obtained in adult hosts after single passage and in sequential passages. Both in the OTT-6050-derived tumor fractions IB-9 and IB-21, previously reported, and in the EB-derived tumors described in the present study the cerebral microenvironment did not appear to have unique properties favoring neural differentiation and maturation, since similar neural features were found in their subcutaneous counterparts. The findings reported suggest that any accentuation of neuroepithelial differentiation elicited by injecting EB's either intracerebrally or subcutaneously is apparently directly related to the total time of in vivo maintenance of the tumor and therefore presumably to the length of time necessary for such maturation to occur.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00430869
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  • 4
    Electronic Resource
    Electronic Resource
    Sensory-feedback system compatible with myoelectric control (1980)
    Springer
    Medical & biological engineering & computing 18 (1980), S. 65-69 
    Details
    ISSN: 1741-0444
    Keywords: Electrocutaneous stimulation ; Myoelectric control ; Prosthetics ; Sensory feedback
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract Progress in the development of a system to provide sensory feedback of the pinch force of an artificial hand is described. Design criteria relating to electrocutaneous stimulation and compatibility with myoelectric control are discussed. Details of a practical system, presently in use by two amputees prior to full-scale clinical evaluation, are presented.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02442481
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  • 5
    Electronic Resource
    Electronic Resource
    Operator error in multistate myoelectric control systems (1978)
    Springer
    Medical & biological engineering & computing 16 (1978), S. 296-301 
    Details
    ISSN: 1741-0444
    Keywords: Error analysis ; Myoelectric control
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Description / Table of Contents: Sommaire Un système de commandes myoélectriques est celui, où le fonctionnement d'un dispositif est contrôlé par le potentiel électrique produit par la contraction volontaire d'un muscle. Ces systèmes sont surtout employés pour la commande de membres artificiels. Les premiers types de systèmes de commande était empiriques, mais de récents travaux ont produit des bases théoriques, pouvant prédire leur performance. Ceci devrait pouvoir améliorer les systèmes déjà existants, et rendre possible le développement de prothèses plus complexes.
    Abstract: Zusammenfassung Bei einem myoelektrischen Steuersystem wird der Betrieb eines Geräts durch ein elektrisches Potential gesteuert, das durch freiillige Kontraktion eines Muskels erzeugt wird. Diese Systeme wurden hauptsächlich zur Kontrolle künstlicher Glieder verwendet. Frühere Entwürfe des Steuersystems waren empirisch, jedoch wurden kürzlich einige theoretische Grundlagen erarbeitet, die ihre Leistung vorbestimmen können. Dieses wird zur Verbesserung der bestehenden Systeme führen und die Entwicklung mehr komplexer Prothesen wahrscheinlicher machen.
    Notes: Abstract A myoelectric control system is one in which the operation of a device is controlled by the electric potential produced by voluntary contraction of a muscle. These systems have been used mainly for the control of artificial limbs. Early design of the control systems was empirical, but recent work has provided some theoretical basis for predicting their performance. This should lead to improvements in existing systems and make feasible the development of more complex prostheses.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02442431
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  • 6
    Electronic Resource
    Electronic Resource
    Error rate in five-state myoelectric control systems (1980)
    Springer
    Medical & biological engineering & computing 18 (1980), S. 287-290 
    Details
    ISSN: 1741-0444
    Keywords: Man-machine systems ; Multistate control ; Myoelectric control ; Prosthetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract A myoelectric control system is one in which the operation of a device is controlled by the electric potential produced by voluntary contraction of a muscle. The utilisation of a single muscle site for the 3-state control of a myoelectric prosthesis has proven beneficial for certain amputees. It has been proposed that a single muscle site could be used for 5-state control, perhaps for an elbow and hand. This paper presents a preliminary study of the error probability for 5-state control.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02443381
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  • 7
    Electronic Resource
    Electronic Resource
    Improved battery saving device for use with myoelectric control systems (1986)
    Springer
    Medical & biological engineering & computing 24 (1986), S. 203-205 
    Details
    ISSN: 1741-0444
    Keywords: Myoelectric control ; Battery saving device
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02443938
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  • 8
    Electronic Resource
    Electronic Resource
    Amplifier input impedances for myoelectric control (1986)
    Springer
    Medical & biological engineering & computing 24 (1986), S. 527-530 
    Details
    ISSN: 1741-0444
    Keywords: Differential amplifiers ; Input impedance ; Myoelectric control
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract Normal requirements for differential and common-mode input impedance of amplifiers for biological signals are reviewed. It is shown that these are not sufficient for satisfactory performance of amplifiers in myoelectric control applications, where accidental opening of the input circuit through electrode movement must not make the system susceptible to external noise. The additional constraint imposed by this application is examined, and a circuit is presented illustrating its practical resolution.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02443970
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  • 9
    Electronic Resource
    Electronic Resource
    A biphasic pulse burst generator for afferent nerve stimulation (1987)
    Springer
    Medical & biological engineering & computing 25 (1987), S. 77-80 
    Details
    ISSN: 1741-0444
    Keywords: Myoelectric control ; Nerve stimulator ; Pulse burst ; Sensory feedback
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02442825
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