Reproductive rhythms, longevity and cancer.
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Circadian Rhythm↗
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Results for “longevity”
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Tipping the balance toward longevity.
Genetic experiments in C. elegans suggested that SIR2, an NAD-dependent protein deacetylase, acts through FOXO/DAF-16 transcription factor to prolong life. Recent studies show that mammalian SIR2 deacetylates FOXO, and may maximize survival by tempering cell death and increasing stress resistance.
Animals↗
Socioeconomic factors affecting the longevity of the Japanese population: a study for 1980 and 1985.
The effects of urbanisation, low income and rejuvenation of the population on life expectancy at birth and at 20, 40 and 65 years of age for males and females in Japan were examined twice, in 1980 and 1985. For males, urbanisation was the major factor determining life expectancy at birth and at age 20 years, and low income was the key determinant of decreased life expectancy except at 65 years of age. For females high income was the factor significantly decreasing life expectancy at 65 years of age in 1980, and rejuvenation of the population inversely influenced life expectancy except at birth in 1985. Life expectancy for all age groups in 1985 was significantly longer than in 1980 for both males and females.
Adult↗
The longevity of some species of helminth parasites in naturally acquired infections of the lesser black-backed gull, Larus fuscus L., in Britain.
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Animals↗
Effects of the host immune response on the longevity, fecundity and position in the intestine of Trichinella spiralis in mice.
In female NIH strain mice, expulsion of a primary infection of the nematode Trichinella spiralis began on day 8 and was virtually complete by day 14 of infection. In secondary and tertiary infections, the number of larvae which established in the intestine was normal, but expulsion began on day 6 and was complete on day 10. In a primary infection the shedding of larvae by female worms began on day 5, reached its peak on days 6--7, began to decrease on day 8 and was minimal by day 10. In secondary and tertiary infections fecundity was depressed. The depression of fecundity occurred slightly in advance of worm loss. During the stable phase of infection, T. spiralis occurred in the anterior half of the small intestine. During expulsion, living worms were found increasingly in more posterior parts of the gut but their fecundity did not vary with position. After direct inoculation into the posterior ileum, adult and larval T. spiralis remained in the posterior half of the small intestine. In this position, larvae established in normal numbers, grew and reproduced normally. Therefore, any part of the small intestine was a suitable site for T. spiralis and expulsion is not merely due to a change in the position of the worms.
Animals↗
On the longevity of fasting ticks, Hyalomma savignyi Gerv.
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Animals↗
Growth, longevity, and the frequency of feeding of Glossina pallidipes Austen.
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Animals↗
Longevity in the setting of tetralogy of Fallot: survival to the 84th year.
A patient with tetralogy of Fallot suffered minimal disability until the age of 45 years, when she developed bacterial endocarditis complicated by hemiplegia. She remained well, but became markedly polycythaemic and, at the age of 50 years, underwent surgical correction to reduce the risk of further thromboembolic incidents. She continued in remarkably good health until her death from lobar pneumonia in her 84th year. We present the post-mortem findings, since as far as we are aware this is the longest recorded survivorship of a patient with tetralogy of Fallot.
Aged↗
A fucosidosis patient with relative longevity and a missense mutation in exon 7 of the alpha-fucosidase gene.
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Exons↗
Longevity and the immune response.
The domino hypothesis of the onset of age associated immune insufficiency suggests that it is the consequence of a cascade of events beginning with involution of the thymus. Involution is associated with a reduced thymic output leading to fewer naïve T cells contributing to the peripheral T-cell pool. Homeostatic mechanisms, which maintain the number of T cells in the peripheral pool within precise limits, induce the proliferation and prolong the survival of resident T cells to fill the niches left vacant by the absent naïve T cells. In this hypothesis, falling thymic output would be matched by resident T-cell proliferation and with age these proliferating cells will reach their replicative limit. Their prolonged survival will lead to the accumulation of cells unable to replicate, producing a decline in immune function and a susceptibility to infection, or certain cancers. Comparison of gender differences in life-span and rates of death in each age group due to infectious or parasitic disease suggests that the immune system in females works more efficiently and effectively for longer than the immune system in males. This leads to the suggestion that involution of the thymus, and hence thymic output, occurs more rapidly in males than in females.
Animals↗
Poly(ADP-ribosyl)ation: a posttranslational protein modification linked with genome protection and mammalian longevity.
Poly(ADP-ribosyl)ation is a posttranslational modification of nuclear proteins catalysed by the 113-kDa enzyme poly(ADP-ribose) polymerase-1 (PARP-1) and, to a lesser extent, by several other recently described polypeptides. The catalytic function of PARP-1 is directly stimulated by DNA strand breaks, thus making poly(ADP-ribosyl)ation one of the immediate cellular responses to oxidative and other types of DNA damage. Poly(ADP-ribosyl)ation plays an important role in the recovery of proliferating cells from certain types of DNA damage, and this has been linked mechanistically with an involvement in DNA base-excision repair. Furthermore PARP-1 activity is necessary to maintain genomic stability under conditions of genotoxic stress and is actually a key regulator of alkylation-induced sister-chromatid exchange formation, imposing a control that is strictly negative and commensurate with the enzyme activity level. Finally, there is a positive correlation between the poly(ADP-ribosyl)ation capacity of mononuclear leukocytes of various mammalian species and species-specific life span. Likewise, lymphoblastoid cell lines derived from human centenarians display a higher poly(ADP-ribosyl)ation capacity than controls. In conclusion, PARP-1 may be viewed as a factor that is responsible for downregulating the rate of genomic instability events, which are provoked by the constant attack by endogenous and exogenous DNA-damaging agents, in such a way as to tune them to a level which is just appropriate for the life span potential of a given species.
Aging↗
Longevity determined by paternal ancestors' nutrition during their slow growth period.
Social circumstances often impinge on later generations in a socio-economic manner, giving children an uneven start in life. Overfeeding and overeating might not be an exception. The pathways might be complex but one direct mechanism could be genomic imprinting and loss of imprinting. An intergenerational "feedforward" control loop has been proposed, that links grandparental nutrition with the grandchild's growth. The mechanism has been speculated to be a specific response, e.g. to their nutritional state, directly modifying the setting of the gametic imprint on one or more genes. This study raises the question: Can overnutrition during a child's slow growth period trigger such direct mechanisms and partly determine mortality? Data were collected by following-up a cohort born in 1905 in Overkalix parish, northernmost Sweden. The probands were characterised by their parents' or grandparents' access to food during their own slow growth period. Availability of food in the area was defined by referring to historical data on harvests and food prices, records of local community meetings and general historical facts. If there was a surfeit of food in the environment when the paternal grandfather was a 9-12 year old boy a shortening of the proband survival could be demonstrated. The influence of parents', maternal grandparents' and paternal grandmothers' access to food during their slow growth period was discounted in a multivariable analysis. The results are indicative of very early programming mechanisms in human adaptation to the social environment.
Adolescent↗
A mathematical model that accounts for the effects of caloric restriction on body weight and longevity.
Several aspects of energy dynamics, such as energy expenditure and caloric intake, are known to affect the aging process. In this article we therefore model the aging process within a mathematical framework describing the energy dynamics of an organism. The resulting model comprises food intake, body growth and survival. The equation for the mortality rate accounts for food consumption and is suited to describe caloric restriction data. For non-growing animals, the expression for the mortality rate reduces to the well-known Gompertz equation. We successfully applied our model to growth and survival data on mice exposed to different food levels.
Animals↗
Using thermal inactivation kinetics to calculate the probability of extreme spore longevity: implications for paleomicrobiology and lithopanspermia.
Thermal inactivation kinetics with extrapolation were used to model the survival probabilities of spores of various Bacillus species over time periods of millions of years at the historical ambient temperatures (25-40 degrees C) encountered within the 250 million-year-old Salado formation, from which the putative ancient spore-forming bacterium Salibacillus marismortui strain 2-9-3 was recovered. The model indicated extremely low-to-moderate survival probabilities for spores of mesophiles. but surprisingly high survival probabilities for thermophilic spores. The significance of the results are discussed in terms of the survival probabilities of (i) terrestrial spores in ancient geologic samples and (ii) spores transported between planets within impact ejecta.
Bacillus↗
Insulin and longevity: antidiabetic biguanides as geroprotectors.
The results of previous experimental studies of effects of antidiabetic biguanides (phenformin and buformin) on life span and spontaneous tumor incidence in mice and rats were recalculated and reanalyzed using standard demographic models of mortality. The chronic treatment of female C3H/Sn mice with phenformin prolonged the mean life span by 21.1% (P < 0.05), the mean life span of the last 10% survivors by 28.4% and the maximum life span by 5.5 months (by 26%) in comparison with the control. The demographic aging rate represented by the estimate of respective Gompertz's parameter decreased by 31.2% and MRDT increased 1.45-fold. The treatment significantly inhibited (4.0-fold, P < 0.01) the incidence of mammary adenocarcinomas in mice. Administration of phenformin to female LIO rats failed to influence the mean life span. At the same time, the mean life span of the last 10% survivors increased by 10.1% (P < 0.05), and maximum life span increased by 3 months (+9.8%). Phenformin attenuated the development of spontaneous tumors in comparison to the control. The treatment of female rats with another antidiabetic biguanide, buformin, slightly increased their mean life span (by 7.3%; P > 0.05). The mean life span of the last 10% survivors increased by 12% (P < 0.05) and the maximum life span increased by 2 months (+5.5%) as compared with controls. The population aging rate decreased by 18.1% (P < 0.05) and MRDT increased 1.22-fold under the influence of buformin (P < 0.05). The total tumor incidence decreased by 49.5% in buformin-treated rats. Both antidiabetic biguanides slightly decreased the body weight, slowed down the age-related decline of the reproductive function in female rats. The results of our experiments provide evidence that antidiabetic biguanides are promising geroprotectors as well as drugs which can be used in the prevention of cancer.
Aging↗
Longevity and ageing in parasitic and free-living nematodes.
In the developing field of biological gerontology, rapid advances have recently been made in the genetics of ageing in the nematode Caenorhabditis elegans. The aim of this work is to develop an understanding of the general mechanisms determining the ageing process. Within the last decade the prospect of actually achieving this somewhat hubristic aim has begun to look startlingly real. In this context, knowledge of every aspect of the biology of ageing in nematodes is of added interest. Here the patterns of ageing observed among parasitic and free-living nematodes are surveyed and compared. Like insects, nematode species exhibit enormous differences in the rate of ageing, with maximum life spans varying over more than a 1000-fold range, from three days in free-living Rhabdias bufonis adults, to at least 15 years in the filarial parasite Loa loa. The possible evolutionary and mechanistic causes of such differences in ageing are discussed.
Aging↗
Transcendental meditation, mindfulness, and longevity: an experimental study with the elderly.
Can direct change in state of consciousness through specific mental techniques extend human life and reverse age-related declines? To address this question, 73 residents of 8 homes for the elderly (mean age = 81 years) were randomly assigned among no treatment and 3 treatments highly similar in external structure and expectations: the Transcendental Meditation (TM) program, mindfulness training (MF) in active distinction making, or a relaxation (low mindfulness) program. A planned comparison indicated that the "restful alert" TM group improved most, followed by MF, in contrast to relaxation and no-treatment groups, on paired associate learning; 2 measures of cognitive flexibility; mental health; systolic blood pressure; and ratings of behavioral flexibility, aging, and treatment efficacy. The MF group improved most, followed by TM, on perceived control and word fluency. After 3 years, survival rate was 100% for TM and 87.5% for MF in contrast to lower rates for other groups.
Adaptation, Psychological↗
Marital history at midlife as a predictor of longevity: alternative explanations to the protective effect of marriage.
The association between marital history at midlife (in 1950) and mortality (as of 1991) was studied in a group of intelligent, educated men and women (N = 1,077) who participated in the Terman Life-Cycle Study initiated by Lewis Terman in 1921. Results confirm that consistently married people live longer than those who have experienced marital breakup but suggest that this is not necessarily due to the protective effects of marriage itself. Individuals who were currently married, but had previously experienced a divorce, were at significantly higher mortality risk compared with consistently married individuals. Furthermore, individuals who had not married by midlife were not at higher mortality risk compared with consistently married individuals. Part of the relationship between marital history and mortality risk may be explained by childhood psychosocial variables, which were associated with both future marital history and mortality risk.
Adolescent↗