caa a22 4500 477082793 CHVBK 20180405111454.0 cr unu---uuuuu 170330e19960701xx s 000 0 eng 10.1007/BF01925574 doi (NATIONALLICENCE)springer-10.1007/BF01925574 Mechanism of age-dependent involution in embryonic chick notochords [Elektronische Daten] [E. Ghanem, M. Cornelissen, H. Thierens, L. De Ridder] To study the possible mechanism of the age-dependent involution of the notochord, isolated mesenchymefree notochords of chick embryos were cultured in vitro and compared with their counterparts in vivo. Two different aspects were evaluated: (1) DNA synthesis measured by [3H]thymidine incorporation and visualized by autoradiography and (2) cell death quantified by counting the number of pyknotic nuclei. The results demonstrate that [3H]thymidine uptake by notochords shows an age-dependent decrease in vitro as well as in vivo. The number of [3H]thymidine-labelled notochord cells, however, is higher in vitro than in vivo. At the same time, there is an age-dependent increase in pyknosis in the notochord in vivo and in vitro. So, during the aging process, the number of both pyknotic nuclei and of [3H]thymidine-labelled nuclei suggest a high turnover of notochord cells in vitro. From these results, we can conclude that the process of involution in aging notochord seems to be controlled by a programmed intrinsic process, which might be influenced partially by the microenvironment in vivo. Birkhäuser Verlag, 1995 Notochord nationallicence [3H]thymidine incorporation nationallicence pyknosis nationallicence age-dependent involution nationallicence Ghanem E. Department of Anatomy, Embryology and Histology, Section Histology, University of Gent, Louis Pasteurlaan 2, B-9000, Gent, (Berlgium) aut Cornelissen M. Department of Anatomy, Embryology and Histology, Section Histology, University of Gent, Louis Pasteurlaan 2, B-9000, Gent, (Berlgium) aut Thierens H. Laboratory for Medical Physics, University of Gent, Gent, (Belgium) aut De Ridder L. Department of Anatomy, Embryology and Histology, Section Histology, University of Gent, Louis Pasteurlaan 2, B-9000, Gent, (Berlgium) aut Experientia Birkhäuser-Verlag 52/7(1996-07-01), 683-686 0014-4754 52:7<683 1996 52 18 https://doi.org/10.1007/BF01925574 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF01925574 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Ghanem E. Department of Anatomy, Embryology and Histology, Section Histology, University of Gent, Louis Pasteurlaan 2, B-9000, Gent, (Berlgium) aut NATIONALLICENCE 700 1- Cornelissen M. Department of Anatomy, Embryology and Histology, Section Histology, University of Gent, Louis Pasteurlaan 2, B-9000, Gent, (Berlgium) aut NATIONALLICENCE 700 1- Thierens H. Laboratory for Medical Physics, University of Gent, Gent, (Belgium) aut NATIONALLICENCE 700 1- De Ridder L. Department of Anatomy, Embryology and Histology, Section Histology, University of Gent, Louis Pasteurlaan 2, B-9000, Gent, (Berlgium) aut NATIONALLICENCE 773 0- Experientia Birkhäuser-Verlag 52/7(1996-07-01), 683-686 0014-4754 52:7<683 1996 52 18 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer