It has been shown that human diploid cells from various donor ages can be arrested in an essentially nonmitotic state by reducing the serum concentration of the incubation medium from 10 to 0.5 percent. Cells incubated at this serum level maintained the population distribution that was present when the cells reached confluency. The population, which has 90 percent of the cells in the G1 phase of the division cycle, was not static and exhibited a low level of mitotic activity with prolonged interdivision times.
South African Medical Journal = Suid-Afrikaanse Tydskrif Vir Geneeskunde
Of all the theories purporting to uncover the roots of childhood behaviour and its extension into adult behaviour, the most cogent relates to the physical and psychological bonds of attachment between infant and mother. It is helpful to divide the human lifespan into three periods, each of which has alternating phases of attachment and detachment.
Ageing in immune reactivity is described at the level of lymphoid cells, at that of lymphoid organs and organ function, and at that of regulation of cell and organ function. Apart from shifts in numbers of lymphoid cell subpopulations, the decrease in communication capacity between lymphoid cell populations and in binding of invaders (like bacteria) is an important aspect of ageing. These aspects may contribute to the decreased immune reactivity to invaders and the enhanced incidence of immune reactions to self-components (autoimmune reactivity).
International Journal of Cancer. Journal International Du Cancer
Dermal fibroblasts from patients with the autosomal dominant cancer-prone disease Basal Cell Nevus Syndrome (BCNS) exhibit a serum dependence, anchorage dependence and in vitro lifespan (about 20 population doublings or less) similar to those of fibroblasts from normal age-, race- and sex-matched controls.
Abortion, primarily as a measure of population control, certainly continues to be an emotional, frustrating and stressful event. In continuation of our work on stressful situations in the female life span and biochemical parameters, serum lipid peroxide levels in terms of malondialdehyde (nmol/ml) have been determined in females undergoing abortion [suction curettage (n = 30), Emcredil-induced abortion (n = 30) and spontaneous abortion (n = 40)] and were compared with appropriate gestational controls.
Lymphocytes have a finite and predictable proliferative life span in culture similar to that observed in fibroblasts. In general, the senescence of human fibroblasts is inevitable and irreversible, but their proliferative life span can be extended by certain DNA tumor virus oncogenes, such as the large T antigen of the SV40 virus. Here, we show that human T lymphocytes (HTL) can be stably transfected with SV40 large T and that expression of T antigen extended the life span of T cell cultures.
We applied the Weibull distribution to the life-table and age-patterns of diseases in Japan. The life-table follows a composite Weibull distribution composed of initial failure and two stage wear-out failure periods. The extension of lifespan during the past century is manifested as increases in the scale parameters in all three periods and the shape parameters in the wear-out periods with female predominancy. The shape parameters of diseases show time-independent sex-dependent specific values.
Non-Hodgkin lymphoma is seen in approximately 5% of patients with AIDS. In recent years, the incidence has increased due to an extension of the average lifespan of HIV-infected individuals. In this article we describe the histological and clinical features of 45 patients with HIV-related non-Hodgkin lymphoma seen at the Academic Medical Centre between 1984 and 1991. There were 43 men and 2 women with a median age of 40 years. Most patients had high-grade B-cell lymphoma; 85% had extranodal sites. Prognosis was poor: overall median survival was only 3.8 months.
BACKGROUND: Among patients with well differentiated papillary thyroid carcinoma who generally have an excellent prognosis and a near-normal lifespan, there exist subsets of patients who have significant risk for morbidity and mortality from this disease. It is important to define the patterns of disease progression and the clinical outcome of such patients to develop effective surveillance and treatment strategies.
The biology of telomeres and telomerase has been the subject of intensive investigative effort since it became evident that they play a significant role in two important biological processes, the loss of cellular replicative capacity inherent to organismal ageing and the unrestricted cell proliferation characteristic of carcinogenesis. Telomere shortening in normal cells is a result of DNA replication events, and reduction beyond a critical length is a signal for cellular senescence.