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  • 1
    Electronic Resource
    Electronic Resource
    Leu-7 immunoreactivity in human and rat embryonic hearts, with special reference to the development of the conduction tissue (1990)
    Springer
    Anatomy and embryology 182 (1990), S. 553-562 
    Details
    ISSN: 1432-0568
    Keywords: Immunohistochemistry ; Leu-7 ; Conduction system ; Embryo
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The distribution pattern of Leu-7 (HNK-1) in developing human embryonic hearts and rat hearts was studied by immunohistochemistry. Human and rat embryos at Streeter's stages XIII ∼ XX and fetus stage I were used. Leu-7, which is absent in the newborn rat heart, is expressed transiently in the embryo and fetus I stages. The earliest embryonic heart shows two incomplete circular structures with immunoreactivity in the myocardium along the primitive atrioventricular cushion and bulboventricular canal. These two structures become localized topographically in the definitive atrioventricular node and atrioventricular bundle after rearrangement and partial disappearance during embryonic development. At Streeter's stages XVIII ∼ XX, Leu-7 immunoreactivity appears to localize topographically in almost all the pathways of the conduction system, although some discontinuities are observed in the atrioventricular junction and atrial internodal tracts. Thereafter, immunoreactivity decreases gradually and differentially by site and stage. The precise nature of Leu-7 immunoreactive cells, that is, whether or not they are neurogenic or myogenic, is not revealed by this study. The present observations are discussed in connection with the hypothesis that specialized ring tissue is the primordium of the conduction system.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00186462
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Immunoelectron microscopic localization of HNK-1 in the embryonic rat heart (1994)
    Springer
    Anatomy and embryology 190 (1994), S. 13-20 
    Details
    ISSN: 1432-0568
    Keywords: HNK-1 ; Immunoelectron microscopy ; Conduction system ; Embryo
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract To confirm the role of HNK-1 in conduction tissue, the ultrastructural localization of monoclonal antibody HNK-1 was analyzed in developing rat hearts at embryonal day 14.5 by immunoelectron microscopic labeling procedures with post-embedding immunogold staining. Tissue sections in different planes containing the sino-atrial (SA) node, atrio-ventricular (AV) node and His bundle were used to demonstrate HNK-1. Immunogold labeling was detected on the cell surfaces and in the extracellular matrices of cells that had features common to conduction tissue cells. Non-specialized contractile myocytes were not labeled by this antibody. Furthermore, immunogold labeling was more prominent in wide intercellular spaces than in narrow intercellular spaces, and rarely observed in cell-cell contact regions. The cell surfaces and extracellular matrices of mesenchymal cells in the endocardial cushion, which contacts the His bundle, were also positive, suggesting the involvement of tract formation to the AV node. These findings may indicate that HNK-1 plays an important role in cell-cell adhesion processes both temporally and spatially in the developing conduction tissue. It was concluded, therefore, that HNK-1 is a suitable marker of the embryonic heart conduction system and might be useful in analyzing anomalous conduction systems, as in congenital heart disease.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00185842
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Effect of aging and dietary restriction on hepatocyte proliferation and death in male F344 rats (1997)
    Springer
    Cell & tissue research 288 (1997), S. 69-77 
    Details
    ISSN: 1432-0878
    Keywords: Key words: Aging ; Dietary restriction ; Hepatocytes ; Cell proliferation ; Proliferating cell nuclear antigen ; Cell death ; Terminal dUTP nick end labeling (TUNEL) ; Rat (Fischer 344)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. The proliferation and death of hepatocytes in rats fed ad libitum and rats on dietary restriction were evaluated in 3 to 24-month-old rats by employing immunocytochemistry for proliferating cell nuclear antigen (PCNA) and terminal dUTP nick end labeling (TUNEL). These techniques were also used to examine hepatic tissue infiltrated with leukemic cells in 24-month-old rats fed ad libitum. PCNA-strongly positive hepatocytes, PCNA-positive hepatocytes, and TUNEL-positive hepatocytes were reported previously to be equivalent to hepatocytes in the S phase, hepatocytes in the cell cycle, and dying hepatocytes, respectively. The proportion of PCNA-strongly positive hepatocytes and PCNA-positive hepatocytes declined with age. Dietary restriction diminished PCNA-strongly positive hepatocytes significantly but not PCNA-positive hepatocytes in young rats, but the proportion of PCNA-strongly positive hepatocytes was significantly higher following dietary restriction than that in rats fed ad libitum in advanced age. Growth stimulation by leukemic cell infiltration resulted in a recovery of the age-related decline of PCNA-strongly positive hepatocytes. Aging was associated with a progressive increase in the proportion of TUNEL-positive hepatocytes, with a smaller effect following dietary restriction than in rats fed ad libitum after 6 months of age. Our results indicate that age and dietary restriction induce proliferative inhibition. The inhibition depends on PCNA expression; this suggests that suppression of cell proliferation and cell death are enhanced in hepatocytes of senile rats.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004410050793
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    Paper (German National Licenses)
    Fulltext
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