Tissue culture in aging research: present status and prospects

Cellular senescence revisited: a review

The field of cellular senescence (cytogerontology) is reviewed. The historical precedence for investigation in this field is summarized, and placed in the context of more recent studies of the regulation of cellular proliferation and differentiation. The now-classical embryonic lung fibroblast model is compared to models utilizing other cell types as well as cells from donors of different ages and phenotypes. Modulation of cellular senescence by growth factors, hormones, and genetic manipulation is contrasted, but newer studies in oncogene involvement are omitted. A current consensus would include the view that the life span of normal diploid cells in culture is limited, is under genetic control, and is capable of being modified. Finally, embryonic cells aging in vitro share certain characteristics with early passage cells derived from donors of increasing age.

Memorial lecture: Verzár's ideas on the age-dependent protein cross-linking in the light of the present knowledge

This lecture was aimed to commemorate the centenary of the birthday (18 September 1886) of Fritz Verzár, one of the most important European founders of experimental gerontology. He was an exceptionally creative scientist who contributed considerably to the development of physiology in this century: he achieved important results in the fields of intestinal absorption, in the adrenal gland's function, and finally, from 1952 until his death (1979), he was creator, promotor and one of the best leaders of experimental gerontology. His idea about the age-dependent cross-linking of protein molecules as a general cause of cell aging--studied by him mainly using the collagen as a model, however, extended also to the nucleoproteins--was a pioneer's work. Yet, its significance was not immediately recognized, the contemporary scientists could not interpret his thoughts in the terms of test-tube biochemistry. However, about a decade later, in the sixties and afterwards, an increasing body of evidence has been accumulated indicating that Verzár was right: the most general age-dependent alteration of the proteins in the living systems known so far is a posttranslational modification of their structure and conformation due to the aggressive effects of the oxygen free radicals. Consequences of these thoughts are being realized nowadays in theory and practice. The present generation of scientists expresses its respect and recognition to Fritz Verzár whose life and activity have been teaching us that aging can be understood, if we find the proper theoretical approach to it.