Human lymphocytes were either exposed to X-irradiation (25 to 200 rads) or treated with H2O2 (9.1 to 291 microM) at 4 degrees C and the extent of DNA migration was measured using a single-cell microgel electrophoresis technique under alkaline conditions. Both agents induced a significant increase in DNA migration, beginning at the lowest dose evaluated. Migration patterns were relatively homogeneous among cells exposed to X-rays but heterogeneous among cells treated with H2O2. An analysis of repair kinetics following exposure to 200 rads X-rays was conducted with lymphocytes obtained from three individuals. The bulk of the DNA repair occurred within the first 15 min, while all of the repair was essentially complete by 120 min after exposure. However, some cells demonstrated no repair during this incubation period while other cells demonstrated DNA migration patterns indicative of more damage than that induced by the initial irradiation with X-rays. This technique appears to be sensitive and useful for detecting damage and repair in single cells.

The objective of this study is to determine the range of complex physical and cognitive abilities of older men and women functioning at high, medium and impaired ranges and to determine the psychosocial and physiological conditions that discriminate those in the high functioning group from those functioning at middle or impaired ranges. The subjects for this study were drawn from men and women aged 70-79 from 3 Established Populations for the Epidemiologic Study of the Elderly (EPESE) programs in East Boston MA, New Haven CT, and Durham County NC screened on the basis of criteria of physical and cognitive function. In 1988, 4030 men and women were screened as part of their annual EPESE interview. 1192 men and women met criteria for "high functioning". Age and sex-matched subjects were selected to represent the medium (n = 80) and low (n = 82) functioning groups. Physical and cognitive functioning was assessed from performance-based examinations and self-reported abilities. Physical function measures focused on balance, gait, and upper body strength. Cognitive exams assessed memory, language, abstraction, and praxis. Significant differences for every performance-based examination of physical and cognitive function were observed across functioning groups. Low functioning subjects were almost 3 times as likely to have an income of < or = $5000 compared to the high functioning group. They were less likely to have completed high school. High functioning subjects smoked cigarettes less and exercised more than others. They had higher levels of DHEA-S and peak expiratory flow rate. High functioning elders were more likely to engage in volunteer activities and score higher on scales of self-efficacy, mastery and report fewer psychiatric symptoms.

Differences between early and late passage cell cultures on the organelle and macromolecular levels have been attributed to cellular "aging." However, concern has been expressed over whether changes in diploid cell populations after serial passage in vitro accurately reflect human cellular aging in vivo. Studies were therefore undertaken to determine if significant differences would be observed in the in vitro lifespans of skin fibroblast cultures from old and young normal, nonhospitalized volunteers and to examine if parameters that change with in vitro "aging" are altered as a function of age in The limited lifespan of cultured human diploid fibroblasts in vitro has led to their extensive utilization as a model system for studying human cellular aging (1-3). These human fetal lung fibroblasts in their last passages are often referred to as representing "aged" cell populations (4-6). Differences between early and late passage cell cultures on the organelle and macromolecular levels have been attributed to cellular "aging" (4-6). However, concern has been expressed over whether changes in diploid cell populations after serial passage in vitro accurately reflects human cellular aging in vivo (7-9). One of the most frequently cited justifications for the use of cultured fibroblasts for studying human cellular aging is the reported decline in the cumulative number of cell population replications in vitro and earlier onset of cell culture senescence with the increasing age of the cell culture donor (10, 11). Recently, however, the statistical analysis and population selection used in these studies have been questioned (7,8).The studies to be described in this report had two major goals: (i) to determine if statistically significant differences would be observed in the onset of cell culture senescence and the cumulative replication capacity of fibroblast cultures derived from old and young normal, nonhospitalized human volunteers; and (ii) to examine if parameters that change with increased in vitro "aging" are altered as a function of in vivo age. This latter asAbbreviation: CPD, cell population doublings. * Present address: Tokyo Metropolitan Institute of Gerontology, Sakaecho, Itabashiku, Tokyo-173, Japan. pect was approached by comparing cell population replication rate, percent replicating cells, cell number at confluency, cell volume, and cellular macromolecular contents in cell cultures from old and young human donors (aging in vivo) as well as in early and late passage cell cultures ("aging" in vitro). MATERIALS AND METHODSCell Culture. After informed consent had been obtained, skin punch biopsies, 2 mm in diameter, were performed on the inner aspect of the upper arm of nonhospitalized male volunteers. The subjects were interviewed prior to biopsy, and those individuals with a history of diabetes or who were receiving steroid medication were not included in this study. The skin specimen was divided into four equal explants and two each were placed between coverglass sandwiches in Leighton tubes. ...

Genes that act inside the cell to negatively regulate proliferation are of great interest because of their implications for such processes as development and cancer, but these genes have been difficult to clone. This report details the cloning and analysis of cDNA for prohibitin, a novel mammalian antiproliferative protein. Microinjection of synthetic prohibitin mRNA blocks entry into S phase in both normal fibroblasts and HeLa cells. Microinjection of an antisense oligonucleotide stimulates entry into S phase. By sequence comparison, the prohibitin gene appears to be the mammalian analog of Cc, a Drosophila gene that is vital for normal development.

No abstract

No abstract

No abstract

No abstract