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  1. Article: The Adaptability of Somatic Stem Cells: A Review.

    Tweedell, Kenyon S

    Journal of stem cells & regenerative medicine

    2017  Volume 13, Issue 1, Page(s) 3–13

    Abstract: Cell and tissue specific somatic stem cells develop as dynamic populations of precursor cells to discrete tissue and organ differentiation during embryonic and fetal stages and their potential evolves with development. Some of their progeny are ... ...

    Abstract Cell and tissue specific somatic stem cells develop as dynamic populations of precursor cells to discrete tissue and organ differentiation during embryonic and fetal stages and their potential evolves with development. Some of their progeny are sequestered into separate cell niches of tissues as adult somatic stem cells at various times during organ development and differentiation These are diverse cell populations of stem and progenitor cells that respond to homeostatic needs for cell and tissue maintenance and the cycling of differentiated cells for physiological/ endocrinological changes. Nominally, multipotent stem cells in one or more niches follow specific lineages of differentiation that can be followed by diverse markers of differentiation. The activation of precursors appears to be stochastic and results in a population of heterogeneous progenitor cells. When variations in the functional need of the tissue or organ occurs, the progenitor cells exhibit flexibility in their differentiation capacity. Regulation of the progenitors is the result of signals from the stem cell niche that can cause adaptive changes in the behavior or function of the stem -progenitor cell lineage. A possible mechanism may be alteration in the differentiation capacity of the resident or introduced cells. Certain quiescent stem cells also serve as a potential cell reservoir for trauma induced cell regeneration through adaptive changes in differentiation of stem cells, progenitor cells and differentiated cells. If the stem-progenitor cell population is normally depleted or destroyed by trauma, differentiated cells from the niche microenvironment can restore the specific stem potency which suggests the process of dedifferentiation.
    Language English
    Publishing date 2017-05-30
    Publishing country India
    Document type Journal Article ; Review
    ZDB-ID 2587301-5
    ISSN 0973-7154
    ISSN 0973-7154
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article ; Online: The urodele limb regeneration blastema: the cell potential.

    Tweedell, Kenyon S

    TheScientificWorldJournal

    2010  Volume 10, Page(s) 954–971

    Abstract: The developmental potential of the limb regeneration blastema, a mass of mesenchymal cells of mixed origins, was once considered as being pluripotent, capable of forming all cell types. Now evidence asserts that the blastema is a heterogeneous mixture of ...

    Abstract The developmental potential of the limb regeneration blastema, a mass of mesenchymal cells of mixed origins, was once considered as being pluripotent, capable of forming all cell types. Now evidence asserts that the blastema is a heterogeneous mixture of progenitor cells derived from tissues of the amputation site, with limited developmental potential, plus various stem cells with multipotent abilities. Many specialized cells, bone, cartilage, muscle, and Schwann cells, at the injury site undergo dedifferentiation to a progenitor state and maintain their cell lineage as they redifferentiate in the regenerate. Muscle satellite reserve stem cells that are active in repair of injured muscle may also dedifferentiate and contribute new muscle cells to the limb blastema. Other cells from the dermis act as multipotent stem cells that replenish dermal fibroblasts and differentiate into cartilage. The blastema primordium is a self-organized, equipotential system, but at the cellular level can compensate for specific cell loss. It is able to induce dedifferentiation of introduced exogenous cells and such cells may be transformed into new cell types. Indigenous cells of the blastema associated with amputated tissues may also transform or possibly transdifferentiate into new cell types. The blastema is a microenvironment that enables dedifferentiation, redifferentiation, transdifferentiation, and stem cell activation, leading to progenitor cells of the limb regenerate.
    MeSH term(s) Animals ; Cell Differentiation ; Extremities/embryology ; Extremities/physiology ; Regeneration ; Urodela/embryology ; Urodela/physiology
    Language English
    Publishing date 2010-05-31
    Publishing country United States
    Document type Journal Article ; Review
    ZDB-ID 2075968-X
    ISSN 1537-744X ; 1537-744X
    ISSN (online) 1537-744X
    ISSN 1537-744X
    DOI 10.1100/tsw.2010.115
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  3. Article: New paths to pluripotent stem cells.

    Tweedell, Kenyon S

    Current stem cell research & therapy

    2008  Volume 3, Issue 3, Page(s) 151–162

    Abstract: Stem cells obtained from early mammalian embryos and the subsequent establishment of self replicating embryonic stem cell lines (ES) provided a legacy resource of pluripotent cells capable of differentiating into specific cell lineages of the adult ... ...

    Abstract Stem cells obtained from early mammalian embryos and the subsequent establishment of self replicating embryonic stem cell lines (ES) provided a legacy resource of pluripotent cells capable of differentiating into specific cell lineages of the adult organism. Still the most versatile source of pluripotent cells, their application to potential human therapeutic use has been encumbered by various technical and ethical objections. New sources of embryonic pluripotent stem cells have been sought, the isolation of ES cell lines from a single blastomere that avoids destruction of the human embryo, the use of arrested embryos no longer capable of completing development or using post-implantation embryos as stem cell providers. The successful cloning and reprogramming of adult animal cell nuclei by somatic cell nuclear transplantation (SCNT) or nuclear transfer (NT) provides stem cells tailored to the donor organism, though a step away for human use. Variations in this procedure are altered SCNT, that would block human use for reproduction and the use of parthenotes to induce pluripotent stem cell lines. All of these NT methods depend upon a very limited supply of healthy oocyte host cells. Enucleated fertilized eggs have been substituted for oocytes and the production of stem cell somatic cell hybrids by cell fusion have potential use for nuclear transfer ES cells not directly dependent on oocytes. Recovery of cells from human amniotic fluid has yielded stem cells that share some pluripotent characteristics but are multipotent stem cells. Adult somatic cells have been reprogrammed recently by retroviral transduction using four transcription factors to induce pluripotent stem cells (iPS) with great promise. Each of these procedures has limitations at present for extensive use in human regenerative medicine.
    MeSH term(s) Animals ; Cell Line ; Embryonic Stem Cells/cytology ; Humans ; Pluripotent Stem Cells/cytology
    Language English
    Publishing date 2008-03-01
    Publishing country United Arab Emirates
    Document type Journal Article ; Review
    ZDB-ID 2251937-3
    ISSN 1574-888X
    ISSN 1574-888X
    DOI 10.2174/157488808785740361
    Database MEDical Literature Analysis and Retrieval System OnLINE

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    In stock of ZB MED Cologne/Königswinter

    Zs.A 6399: Show issues Location:
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  4. Article ; Online: The Urodele Limb Regeneration Blastema

    Kenyon S. Tweedell

    The Scientific World Journal, Vol 10, Pp 954-

    The Cell Potential

    2010  Volume 971

    Abstract: The developmental potential of the limb regeneration blastema, a mass of mesenchymal cells of mixed origins, was once considered as being pluripotent, capable of forming all cell types. Now evidence asserts that the blastema is a heterogeneous mixture of ...

    Abstract The developmental potential of the limb regeneration blastema, a mass of mesenchymal cells of mixed origins, was once considered as being pluripotent, capable of forming all cell types. Now evidence asserts that the blastema is a heterogeneous mixture of progenitor cells derived from tissues of the amputation site, with limited developmental potential, plus various stem cells with multipotent abilities. Many specialized cells, bone, cartilage, muscle, and Schwann cells, at the injury site undergo dedifferentiation to a progenitor state and maintain their cell lineage as they redifferentiate in the regenerate. Muscle satellite reserve stem cells that are active in repair of injured muscle may also dedifferentiate and contribute new muscle cells to the limb blastema. Other cells from the dermis act as multipotent stem cells that replenish dermal fibroblasts and differentiate into cartilage. The blastema primordium is a self-organized, equipotential system, but at the cellular level can compensate for specific cell loss. It is able to induce dedifferentiation of introduced exogenous cells and such cells may be transformed into new cell types. Indigenous cells of the blastema associated with amputated tissues may also transform or possibly transdifferentiate into new cell types. The blastema is a microenvironment that enables dedifferentiation, redifferentiation, transdifferentiation, and stem cell activation, leading to progenitor cells of the limb regenerate.
    Keywords Science (General) ; Q1-390
    Subject code 571
    Language English
    Publishing date 2010-01-01T00:00:00Z
    Publisher Hindawi Publishing Corporation
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

    Full text online

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  5. Article ; Online: Embryos, clones, and stem cells: a scientific primer.

    Tweedell, Kenyon S

    TheScientificWorldJournal

    2004  Volume 4, Page(s) 662–715

    Abstract: This article is intended to give the nonspecialist an insight into the nuances of "clones", cloning, and stem cells. It distinguishes embryonic and adult stem cells, their normal function in the organism, their origin, and how they are recovered to ... ...

    Abstract This article is intended to give the nonspecialist an insight into the nuances of "clones", cloning, and stem cells. It distinguishes embryonic and adult stem cells, their normal function in the organism, their origin, and how they are recovered to produce stem cell lines in culture. As background, the fundamental processes of embryo development are reviewed and defined, since the manipulation of stem cell lines into desired specialized cells employs many of the same events. Stem cells are defined and characterized and shown how they function in the intact organism during early development and later during cell regeneration in the adult. The complexity of stem cell recovery and their manipulation into specific cells and tissue is illustrated by reviewing current experimentation on both embryonic and adult stem cells in animals and limited research on human stem cell lines. The current and projected use of stem cells for human diseases and repair, along with the expanding methodology for the recovery of human embryonic stem cells, is described. An assessment on the use of human embryonic stem cells is considered from ethical, legal, religious, and political viewpoints.
    MeSH term(s) Animals ; Clone Cells/physiology ; Embryo, Mammalian/physiology ; Humans ; Stem Cells/physiology
    Language English
    Publishing date 2004-08-18
    Publishing country United States
    Document type Journal Article ; Review
    ISSN 1537-744X
    ISSN (online) 1537-744X
    DOI 10.1100/tsw.2004.121
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  6. Article ; Online: Embryos, Clones, and Stem Cells

    Kenyon S. Tweedell

    The Scientific World Journal, Vol 4, Pp 662-

    A Scientific Primer

    2004  Volume 715

    Abstract: This article is intended to give the nonspecialist an insight into the nuances of “clones”, cloning, and stem cells. It distinguishes embryonic and adult stem cells, their normal function in the organism, their origin, and how they are recovered to ... ...

    Abstract This article is intended to give the nonspecialist an insight into the nuances of “clones”, cloning, and stem cells. It distinguishes embryonic and adult stem cells, their normal function in the organism, their origin, and how they are recovered to produce stem cell lines in culture. As background, the fundamental processes of embryo development are reviewed and defined, since the manipulation of stem cell lines into desired specialized cells employs many of the same events. Stem cells are defined and characterized and shown how they function in the intact organism during early development and later during cell regeneration in the adult. The complexity of stem cell recovery and their manipulation into specific cells and tissue is illustrated by reviewing current experimentation on both embryonic and adult stem cells in animals and limited research on human stem cell lines. The current and projected use of stem cells for human diseases and repair, along with the expanding methodology for the recovery of human embryonic stem cells, is described. An assessment on the use of human embryonic stem cells is considered from ethical, legal, religious, and political viewpoints.
    Keywords Technology ; T ; Medicine ; R ; Science ; Q
    Subject code 571
    Language English
    Publishing date 2004-01-01T00:00:00Z
    Publisher Hindawi Limited
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

    Full text online

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  7. Article ; Online: Changes in Nucleolar and Ribosomal RNA of the Frog Kidney after Malignant Transformation by the Lucke Tumor Herpesvirus

    Tweedell, Kenyon S. / Malin, John H.

    Pathobiology - Exploring the basis of disease

    1984  Volume 52, Issue 3, Page(s) 196–206

    Abstract: Malignant transformation of the frog kidney by the Lucke herpesvirus changes the nucleotide base composition of normal kidney nucleolar and ribosomal RNA. In the Lucke tumor there is a moderate decline in guanylic acid and a sharp decline in adenylic ... ...

    Abstract Malignant transformation of the frog kidney by the Lucke herpesvirus changes the nucleotide base composition of normal kidney nucleolar and ribosomal RNA. In the Lucke tumor there is a moderate decline in guanylic acid and a sharp decline in adenylic acid levels. Conversely, there is a sharp increase in cytidylic acid and uridylic acid levels in the tumor cells. However, there was an increase in the G + C content of nucleolar and ribosomal RNA over that obtained from the normal kidney cells. Nearly identical quantitative changes in the base composition of each RNA species were measured for the adult (spontaneous) mesonephric carcinoma and a Lucke-herpesvirus-induced pronephric tumor cell line; similar correspondence was obtained for the normal adult mesonephros and a normal pronephric cell line.
    Keywords Frog pronephric tumor ; Lucke herpesvirus ; Nucleolar, ribosomal RNA
    Language English
    Publisher S. Karger AG
    Publishing place Basel
    Publishing country Switzerland
    Document type Article ; Online
    ZDB-ID 1022703-9
    ISSN 1423-0291 ; 1015-2008 ; 1015-2008
    ISSN (online) 1423-0291
    ISSN 1015-2008
    DOI 10.1159/000163261
    Database Karger publisher's database

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    In stock of ZB MED Cologne/Königswinter

    Ud II Zs.101: Show issues Location:
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  8. Article ; Online: Karyotype Analysis of a Frog Pronephric Tumor Cell Line

    Przybelski, Robert J. / Tweedell, Kenyon S.

    Pathobiology - Exploring the basis of disease

    1978  Volume 46, Issue 5, Page(s) 289–297

    Abstract: Pronephric tumor cell lines, established from explants of a herpes virus induced frog renal adenocarcinoma, were shown to have a aneuploid modal chromosome number of 39. A karyotypic analysis of one line demonstrated the presence of abnormal chromosomes ... ...

    Abstract Pronephric tumor cell lines, established from explants of a herpes virus induced frog renal adenocarcinoma, were shown to have a aneuploid modal chromosome number of 39. A karyotypic analysis of one line demonstrated the presence of abnormal chromosomes and chromosomal aberrations not previously reported for Lucké tumor cells. The cell line was characterized by two marker chromosomes of high incidence, but there was no evidence of a stemline population of tumor cells.
    Keywords Frog pronephric tumor line ; Karyotype ; Herpes virus
    Language English
    Publisher S. Karger AG
    Publishing place Basel
    Publishing country Switzerland
    Document type Article ; Online
    ZDB-ID 1022703-9
    ISSN 1423-0291 ; 1015-2008 ; 1015-2008
    ISSN (online) 1423-0291
    ISSN 1015-2008
    DOI 10.1159/000162905
    Database Karger publisher's database

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    In stock of ZB MED Cologne/Königswinter

    Ud II Zs.101: Show issues Location:
    Je nach Verfügbarkeit (siehe Angabe bei Bestand)
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