Effects of age, replicative lifespan and growth rate of human nucleus pulposus cells on selecting age range for cell-based biological therapies for degenerative disc diseases.

Autologous disc cell implantation, growth factors and gene therapy appear to be promising therapies for disc regeneration. Unfortunately, the replicative lifespan and growth kinetics of human nucleus pulposus (NP) cells related to host age are unclear. We investigated the potential relations among age, replicative lifespan and growth rate of NP cells, and determined the age range that is suitable for cell-based biological therapies for degenerative disc diseases. We used NP tissues classified by decade into five age groups: 30s, 40s, 50s, 60s and 70s. The mean cumulative population doubling level (PDL) and population doubling rate (PDR) of NP cells were assessed by decade. We also investigated correlations between cumulative PDL and age, and between PDR and age. The mean cumulative PDL and PDR decreased significantly in patients in their 60s. The mean cumulative PDL and PDR in the younger groups (30s, 40s and 50s) were significantly higher than those in the older groups (60s and 70s). There also were significant negative correlations between cumulative PDL and age, and between PDR and age. We found that the replicative lifespan and growth rate of human NP cells decreased with age. The replicative potential of NP cells decreased significantly in patients 60 years old and older. Young individuals less than 60 years old may be suitable candidates for NP cell-based biological therapies for treating degenerative disc diseases.

[The ideal and practice of Greek medical ethics].

This paper is concerned not with medical theories, but with practices of Greek physicians, and I have addressed the subject of medical ethics as related to the Hippocratic tradition. And I have attempted a synthetic account of Greek physicians' actual practice and its ideals in the Hippocratic tradition. My understanding of the tradition succeeds the revelations in the first chapter of my doctoral dissertation, one of them is the fact that Hippocratic tradition is amalgamation of ethical code with rational or scientific medical theory. In the first chapter of this paper, I have attempted a social history of Greek physicians by analyzing Hippocratic writings. The Hippocratic collections, Corpus Hippocraticum, throw light not only on the origins and early development of classical medicine, but on its place in Greek Society. In the second chapter, I aim at understanding of the medical morality in its practice by analyzing the Corpus. Particularly the Oath shall be examined. Some questions, above all, such as "Was it ever a reality or merely a 'counsel of perfection'?" can not be answered. But by the way of the examination of the deontological treatises, the characters of the ethics of Greek physicians become clear. It was the result of outward performance in the relation of inner intention. In the result Greek physicians were the first to attempt to establish a code of behavior for the medical profession and to define the doctor's obligations to the society.