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1

Influence of the quality and quantity of blood ingested on reproductive parameters and life-span in Triatoma infestans (Klug).  

PubMed

In Triatominae, female fecundity and fertility may be affected by age, adult nutritional status (i.e., blood meal source and amount of blood ingested) and number of matings. Triatoma infestans (Klug) is the main vector of Chagas disease in southern South America and considering that reproductive success is intimately associated with the potential for colonizing or re-colonizing new ecotopes in endemic areas, we studied whether the blood meal source and the amount of blood ingested have influence on reproductive parameters. We constitute two groups: couples feeding regularly on guinea pigs and couples feeding regularly on pigeons. We registered quantity of blood ingested, fecundity, fertility, number of matings, days between the first feeding and mating, copula initiation, oviposition initiation and adult life-span. Results showed that females that fed on guinea pigs exhibited high fecundity and fertility, higher number of matings and they needed a lower amount of blood to form an egg. The number of matings and fecundity increased linearly and significantly with the quantity of blood ingested for both meal sources. Results from lineal regression between life-span and fecundity showed a positive and significant relation for both meal sources. The number of matings showed a positive relation with fecundity for both meal sources but significant only for guinea pigs. In T. infestans, the quantity of blood ingested could be a determinant of their reproductive efficiency. This species is mainly adapted to human dwelling and peridomestic structures where there is low host diversity. Considering that this species is in contact with mammals over other food sources, a greater reproductive success may result from an adaptation to this environment. PMID:21672510

Nattero, Julieta; Leonhard, Gustavo; Rodríguez, Claudia S; Crocco, Liliana

2011-08-01

2

Life-Span Extension by Caloric Restriction Is Determined by Type and Level of Food Reduction and by Reproductive Mode in Brachionus manjavacas (Rotifera)  

PubMed Central

We measured life span and fecundity of three reproductive modes in a clone of the monogonont rotifer Brachionus manjavacas subjected to chronic caloric restriction (CCR) over a range of food concentrations or to intermittent fasting (IF). IF increased life span 50%–70% for all three modes, whereas CCR increased life span of asexual females derived from sexually or asexually produced eggs, but not that of sexual females. The main effect of CR on both asexual modes was to delay death at young ages, rather than to prevent death at middle ages or to greatly extend maximum life span; in contrast CR in sexual females greatly increased the life span of a few long-lived individuals. Lifetime fecundity did not decrease with CCR, suggesting a lack of resource allocation trade-off between somatic maintenance and reproduction. Multiple outcomes for a clonal lineage indicate that different responses are established through epigenetic programming, whereas differences in life-span allocations suggest that multiple genetic mechanisms mediate life-span extension.

2013-01-01

3

Life-span extension by caloric restriction is determined by type and level of food reduction and by reproductive mode in Brachionus manjavacas (Rotifera).  

PubMed

We measured life span and fecundity of three reproductive modes in a clone of the monogonont rotifer Brachionus manjavacas subjected to chronic caloric restriction (CCR) over a range of food concentrations or to intermittent fasting (IF). IF increased life span 50%-70% for all three modes, whereas CCR increased life span of asexual females derived from sexually or asexually produced eggs, but not that of sexual females. The main effect of CR on both asexual modes was to delay death at young ages, rather than to prevent death at middle ages or to greatly extend maximum life span; in contrast CR in sexual females greatly increased the life span of a few long-lived individuals. Lifetime fecundity did not decrease with CCR, suggesting a lack of resource allocation trade-off between somatic maintenance and reproduction. Multiple outcomes for a clonal lineage indicate that different responses are established through epigenetic programming, whereas differences in life-span allocations suggest that multiple genetic mechanisms mediate life-span extension. PMID:22904096

Gribble, Kristin E; Welch, David B Mark

2013-04-01

4

Parthenogenetic reproduction of Diaphanosoma celebensis (Crustacea: Cladocera). Effect of algae and algal density on survival, growth, life span and neonate production  

Microsoft Academic Search

The cladoceran Diaphanosoma celebensis Stingelin is reported on for the first time from Indian waters (Mandovi estuary, Goa). Amictic females were maintained in\\u000a the laboratory (temperature 24?±?1?°C and salinity 17 psu) for three successive generations in order to follow the parthenogenetic\\u000a reproductive behaviour, growth, survival and neonate production. The mean life span and body length of adult females in the

Y. Shrivastava; G. G. Mahambre; C. T. Achuthankutty; B. Fernandes; S. C. Goswami; M. Madhupratap

1999-01-01

5

Insulin signaling and life span  

Microsoft Academic Search

Hyperinsulinemia and metabolic diseases are known to be associated with a reduction in life span. In the presence of insulin\\u000a resistance, insulin signaling is selectively impaired, contributing to longevity shortening. Insulin indeed activates a complex\\u000a web of intracellular downstream pathways, which are involved in mechanisms regulating longevity, primarily affecting cellular\\u000a proliferation and apoptosis. Insulin resistance promotes reactive oxygen species (ROS)

Angelo Avogaro; Saula Vigili de Kreutzenberg; Gian Paolo Fadini

2010-01-01

6

Intra-population variation in anadromy and reproductive life span in rainbow trout introduced in the Santa Cruz River, Argentina  

Microsoft Academic Search

Scale patterns, maturational status and otolith microchemistry (strontium to calcium ratios) were analysed in sympatric anadromous and non-anadromous rainbow trout Oncorhynchus mykiss in the Santa Cruz River (Patagonia, Argentina) to investigate the life-history differences of anadromous and non-anadromous lifestyles and the association between maternal origin and progeny life history. The analyses revealed that both forms can give rise to one

C. Riva-Rossi; M. A. Pascual; J. A. Babaluk; M. García-Asorey; N. M. Halden

2007-01-01

7

Life-Span Learning: A Developmental Perspective  

ERIC Educational Resources Information Center

The article discusses learning as embedded processes of development and aging, and as social activity over the life course. The concept of life-span learning is proposed and outlined to discuss these processes as aspects of and propositions in life-span development and aging theory. Life-span learning processes arise and continuously develop in a…

Thornton, James E.

2003-01-01

8

Adolescent Research. A Life Span Developmental Perspective.  

ERIC Educational Resources Information Center

Presents research on pubertal timing and adolescent stress to illustrate the utility of the life-span perspective. Reasons for the apparent dearth of life-span investigations are discussed, the necessity for long-term longitudinal designs is underscored as a major obstacle, and alternative strategies by which life-span research can be implemented…

Berzonsky, M. D.

1983-01-01

9

My Reproductive Life Plan  

MedlinePLUS

... to... Añadir en... Favorites Delicious Digg Google Bookmarks My Reproductive Life Plan Thinking about your goals for ... prevent pregnancy? Am I sure that I or my partner will be able to use the method ...

10

Sex difference in life span affected by female birth rate in modern humans  

Microsoft Academic Search

Sex differences in life span are common in different taxa, including primates, but not well understood. Theory and comparative evidence suggest that differential costs of reproduction between the sexes may explain the differences in sex-biased mortality across large taxonomic groups. The level of sex-specific reproductive effort may thus affect the difference in life span across populations. Modern humans (Homo sapiens),

Alexei A. Maklakov

2008-01-01

11

Life span of the biosphere  

Microsoft Academic Search

Since main sequence stars appear to increase their burning rate as they age, the sun may be thought to have increased its output by 30% since the earth's origin 4.5 billion years ago. Due to the requirement for some means of planetary thermostasis in the maintenance of an equable climate since life began, possible links are considered between the biological,

J. E. Lovelock; M. Whitfield

1982-01-01

12

Families as Life Span Experts  

ERIC Educational Resources Information Center

Professionals dealing with challenging behavior frequently operate detached from the other relationships in the child's life. This narrow approach has been called the unilateral strategy based on the belief that the child's outside world can be ignored and behavior can be changed by administering specific corrective interventions. In contrast,…

Brendtro, Larry K.; Mitchell, Martin L.

2011-01-01

13

The Cost of Uncertain Life Span*  

PubMed Central

A considerable amount of uncertainty surrounds the length of human life. The standard deviation in adult life span is about 15 years in the U.S., and theory and evidence suggest it is costly. I calibrate a utility-theoretic model of preferences over length of life and show that one fewer year in standard deviation is worth about half a mean life year. Differences in the standard deviation exacerbate cross-sectional differences in life expectancy between the U.S. and other industrialized countries, between rich and poor countries, and among poor countries. Accounting for the cost of life-span variance also appears to amplify recently discovered patterns of convergence in world average human well-being. This is partly for methodological reasons and partly because unconditional variance in human length of life, primarily the component due to infant mortality, has exhibited even more convergence than life expectancy.

Edwards, Ryan D.

2012-01-01

14

Life span of the biosphere  

NASA Astrophysics Data System (ADS)

Since main sequence stars appear to increase their burning rate as they age, the sun may be thought to have increased its output by 30% since the earth's origin 4.5 billion years ago. Due to the requirement for some means of planetary thermostasis in the maintenance of an equable climate since life began, possible links are considered between the biological, Gaia hypothesis of Lovelock and Margulis (1974) for climate control, and Walker et al's (in press) model of automatic thermostasis, in which the abundance of such atmospheric greenhouse gases as CO2 adjusts to resist the warming tendency of the increased solar flux. It is concluded that, since atmospheric CO2 is now close to its partial pressure lower limit, the biosphere will on a geological time-scale be soon exposed, without protection, to the predicted solar luminosity increases.

Lovelock, J. E.; Whitfield, M.

1982-04-01

15

Genetic (Co)Variation for Life Span in Rhabditid Nematodes: Role of Mutation, Selection, and History  

PubMed Central

The evolutionary mechanisms maintaining genetic variation in life span, particularly post-reproductive life span, are poorly understood. We characterized the effects of spontaneous mutations on life span in the rhabditid nematodes Caenorhabditis elegans and C. briggsae and standing genetic variance for life span and correlation of life span with fitness in C. briggsae. Mutations decreased mean life span, a signature of directional selection. Mutational correlations between life span and fitness were consistently positive. The average selection coefficient against new mutations in C. briggsae was approximately 2% when homozygous. The pattern of phylogeographic variation in life span is inconsistent with global mutation–selection balance (MSB), but MSB appears to hold at the local level. Standing genetic correlations in C. briggsae reflect mutational correlations at a local scale but not at a broad phylogeographic level. At the local scale, results are broadly consistent with predictions of the “mutation accumulation” hypothesis for the evolution of aging.

Upadhyay, Ambuj; Salomon, Matthew P.; Grigaltchik, Veronica; Baer, Charles F.

2009-01-01

16

A Life-Span Theory of Control  

Microsoft Academic Search

A life-span theory of development is presented that is based on the concepts of primary and secondary control. Primary control refers to behaviors directed at the external environment and involves attempts to change the world to fit the needs and desires of the individual. Secondary control is targeted at internal processes and serves to minimize losses in, maintain, and expand

Jutta Heckhausen; Richard Schulz

1995-01-01

17

Sensorimotor Synchronization across the Life Span  

ERIC Educational Resources Information Center

The present study investigates the contribution of general processing resources as well as other more specific factors to the life-span development of sensorimotor synchronization and its component processes. Within a synchronization tapping paradigm, a group of 286 participants, 6 to 88 years of age, were asked to synchronize finger taps with…

Drewing, Knut; Aschersleben, Gisa; Li, Shu-Chen

2006-01-01

18

A Life Span Concept of Motor Development  

Microsoft Academic Search

A concept of life span motor development is presented. Evolution of the author's concept of motor development is traced from its beginnings in classic developmental theory rooted in the biological sciences. Influenced by contemporary motor control theory and the writings of Milani-Comparetti, mechanistic models of nervous system function were abandoned in favor of active organism concepts. Application of classic developmental

Ann F. VanSant

1989-01-01

19

Attitudes Toward Death Across the Life Span.  

ERIC Educational Resources Information Center

To understand the change and development of people's attitudes toward death over the life span, a 62-item attitude questionnaire on death and dying was administered to 90 adults. Participants included five females and five males in each of nine age categories: 18-20, 20-24, 25-29, 30-34, 35-39, 40-49, 50-59, 60-64, and 65 or older. Participants…

Maiden, Robert; Walker, Gail

20

B cell life span: a review.  

PubMed

Debate has surrounded the subject of B cell life span since it was first measured in mice in the early 1970s. In the 25 years which have passed since then, it has become increasingly apparent that the methods employed to measure rates of B cell turnover, such as [3H]-thymidine labelling, cell transfer or cell ablation, brought about significant disruptions to normal physiology which in themselves might have affected B cell turnover. More recently the use of bromodeoxyuridine has overcome many of these methodological difficulties and has allowed rates of B cell renewal to be measured within B cell subpopulations defined by multiparameter flow cytometry. Such studies have largely resolved the issue, concluding that about 85% of peripheral B cells are phenotypically mature and display first-order exponential kinetics defined by a half-life of 5-6 weeks, whilst the remainder are short-lived with a life span of several days. This review examines both traditional and recent methods and discusses the influence of age, self-tolerance and randomness in the overall shaping of a kinetically stable mature B cell population. PMID:9429891

Fulcher, D A; Basten, A

1997-10-01

21

Genetics, Life Span, Health Span, and the Aging Process in Caenorhabditis elegans  

PubMed Central

As a tool for measuring the aging process, life span has been invaluable in dissecting the genes that modulate longevity. Studies over the past few decades have identified several hundred genes that can modify life span in model organisms such as yeast, worms, and flies. Yet, despite this vast amount of research, we still do not fully understand how the genes that affect life span influence how an organism ages. How does modulation of the genes that affect life span contribute to the aging process? Does life-span extension result in extension of healthy aging? Here, we will focus primarily on the insulin/IGF-1 signaling pathway in Caenorhabditis elegans because members of this pathway have been shown to be associated with extended life span across phylogeny, from worms to humans. I discuss how this connects to the aging process, age-associated disease, and the potential to increase healthy aging in addition to lengthening life span.

2012-01-01

22

Does the Female Life Span Exceed That of the Male  

Microsoft Academic Search

A survey of all the papers relating to life span in Drosophila melanogaster published in Experimental Gerontology from its origin in 1964 to 1981 shows that, contrary to a common belief, the mean life span of females exceeds that of males in only approximately 50% of the cases. It is shown that mean life span, as it is measured in

F. A. Lints; M. Bourgois; A. Delalieux; J. Stoll; C. V. Lints

1983-01-01

23

Stress Proteins in Aging and Life Span  

PubMed Central

Heat shock proteins (HSP) are molecular chaperones and have been implicated in longevity and aging in many species. Their major functions include, chaperoning misfolded or newly synthesized polypeptides, protecting cells from proteotoxic stress, and processing of immunogenic agents. These proteins are expressed constitutively and can be induced by stresses such as heat, oxidative stress and many more. The induction of HSP in aging could potentially maintain protein homeostasis and longevity by refolding the damaged proteins which accumulate during aging and are toxic to cells. HSP are shown to increase life span in model organisms such as C. elegans and decrease aging related proteotoxicity. Thus, decrease in HSP in aging is associated with disruption of cellular homeostasis which causes diseases such as cancer, cell senescence and neurodegeneration. HSP levels are decreased with aging in most organs including neurons. Aging also causes attenuation or alteration of many signaling pathways as well as the expression of transcription factors such as heat shock factor (HSF). The alteration in regulation and synthesis of Forkhead box O3a (FOXO3a) family of transcription factors as well as major antioxidant enzymes [manganese superoxide dismutase (MnSOD), catalase] are also seen in aging. Among many signaling mechanisms involved in altering longevity and aging, the insulin/IGF1 pathway and the Sir2 deacetylase are highly significant. This review inquires into the role of some of these pathways in longevity/aging along with HSP.

Murshid, Ayesha; Eguchi, Takanori; Calderwood, Stuart K.

2014-01-01

24

Metformin Supplementation and Life Span in Fischer-344 Rats  

PubMed Central

Calorie restriction (CR) has been known for more than 70 years to extend life span and delay disease in rodent models. Metformin administration in rodent disease models has been shown to delay cancer incidence and progression, reduce cardiovascular disease and extend life span. To more directly test the potential of metformin supplementation (300 mg/kg/day) as a CR mimetic, life-span studies were performed in Fischer-344 rats and compared with ad libitum feeding and CR (30%). The CR group had significantly reduced food intake and body weight throughout the study. Body weight was significantly reduced in the metformin group compared with control during the middle of the study, despite similar weekly food intake. Although CR significantly extended early life span (25th quantile), metformin supplementation did not significantly increase life span at any quantile (25th, 50th, 75th, or 90th), overall or maximum life span (p > .05) compared with control.

Smith, Daniel L.; Elam, Calvin F.; Mattison, Julie A.; Lane, Mark A.; Roth, George S.; Ingram, Donald K.

2010-01-01

25

A Motivational Theory of Life-Span Development  

Microsoft Academic Search

This article had four goals. First, the authors identified a set of general challenges and questions that a life-span theory of development should address. Second, they presented a comprehensive account of their Motivational Theory of Life-Span Development. They integrated the model of optimization in primary and secondary control and the action-phase model of developmental regulation with their original life-span theory

Jutta Heckhausen; Carsten Wrosch; Richard Schulz

2010-01-01

26

Effect of melatonin and pineal peptide preparation epithalamin on life span and free radical oxidation in Drosophila melanogaster  

Microsoft Academic Search

It was shown previously that epithalamin delays age-related changes in reproductive and immune systems and increases the life span of mice and rats. These effects could be mediated by stimulating influences of epithalamin on synthesis and secretion of melatonin and on free radical processes. A comparative study on the effect of epithalamin and melatonin on both the life span of

Vladimir N Anisimov; Sergey V Mylnikov; Tatyana I Oparina; Vladimir Kh Khavinson

1997-01-01

27

Teaching the Psychology of Aging: A Life-Span Perspective.  

ERIC Educational Resources Information Center

There is a vast body of literature devoted to an examination of life-span development. Several authors have described the characteristics of the life-span approach and have distinguished it from more traditional forms of psychology. Emphasis has been placed on the multidirectional and multidimensional nature of development and change, as well as…

Seltzer, Mildred M.

28

Life Span of Skin Fibroblasts in Patients with Systemic Sclerosis  

Microsoft Academic Search

Background: It remains unknown whether the life span of systemic sclerosis (SSc) skin fibroblasts (FB) and that of normals are the same or not, though SSc skin FB have been shown to present abnormalities such as elevated collagen synthesis. Objective: To find out whether the life span of SSc skin FB and that of normals are the same or not.

T. Ohtsuka

1998-01-01

29

Boundaries of life: estimating the life span of the biosphere  

NASA Astrophysics Data System (ADS)

We present a minimal model for the global carbon cycle of the Earth containing the reservoirs mantle ocean floor continental crust continental biosphere and the Kerogen as well as the aggregated reservoir ocean and atmosphere and obtain reasonable values for the present distribution of carbon in the surface reservoirs of the Earth The Earth system model for the long-term carbon cycle is specified by introducing three different types of biosphere prokaryotes eucaryotes and complex multicellular life They are characterized by different global temperature tolerance windows prokaryotes 2oC 100oC eucaryotes 5oC 45oC complex multicellular life 0oC 30oC From the Archaean to the future there always exists a prokaryotic biosphere 2 Gyr ago eucaryotic life first appears because the global surface temperature reaches the tolerance window for eucaryotes The emergence of complex multicellular life is connected with an explosive increase in biomass and a strong decrease in Cambrian global surface temperature at about 0 54 Gyr ago In the long-term future the three types of biosphere will die out in reverse sequence of their appearance For realistic values of the biotic enhancement of weathering there is no bistability in the future solutions for complex life Therefore complex organisms will not extinct by an implosion in comparison to the Cambrian explosion Eucaryotes and complex life become extinct because of too high surface temperatures in the future The ultimate life span of the biosphere is defined by the extinction of procaryotes in about 1 6 Gyr

Franck, S.; Bounama, C.; von Bloh, W.

30

Extending the Human Life Span: Social Policy and Social Ethics.  

National Technical Information Service (NTIS)

This document contains some papers and discussions dealing with extension of the human life span, which emanated from a conference attended by social and biological scientists, policymakers, and social ethicists. Authors were asked to focus upon the gener...

B. L. Neugarten R. J. Havighurst

1977-01-01

31

Effect of deleterious mutations on life span in Drosophila melanogaster.  

PubMed

Evolutionary theories of aging assume that the accumulation of deleterious mutations will reduce life span. We tested this assumption in Drosophila melanogaster by a newly designed mating scheme, in which mutations accumulate on the Binscy balancer X chromosome in heterozygous females in the absence of selection and recombination. We found that the life span of Binscy/RY(L) males from this cross decreased faster than the life span of their sibling controls over time in two of three runs, and that there was an age-specific increase in mortality in the Binscy/RY(L) males with time in one of three runs. Therefore, the accumulation of deleterious mutations can decrease life span by increasing fragility and can cause age-specific changes in mortality. These results support the evolutionary theory of aging. PMID:17234817

Gong, Yi; Thompson, James N; Woodruff, R C

2006-12-01

32

A Motivational Theory of Life-Span Development  

PubMed Central

This article had four goals. First, the authors identified a set of general challenges and questions that a life-span theory of development should address. Second, they presented a comprehensive account of their Motivational Theory of Life-Span Development. They integrated the model of optimization in primary and secondary control and the action-phase model of developmental regulation with their original life-span theory of control to present a comprehensive theory of development. Third, they reviewed the relevant empirical literature testing key propositions of the Motivational Theory of Life-Span Development. Finally, because the conceptual reach of their theory goes far beyond the current empirical base, they pointed out areas that deserve further and more focused empirical inquiry.

Heckhausen, Jutta; Wrosch, Carsten; Schulz, Richard

2010-01-01

33

Circadian Rhythms, Aging, and Life Span in Mammals  

NSDL National Science Digital Library

Resetting the circadian clock leads to well being and increased life span, whereas clock disruption is associated with aging and morbidity. Increased longevity and improved health can be achieved by different feeding regimens that reset circadian rhythms and may lead to better synchrony in metabolism and physiology. This review focuses on recent findings concerning the relationships between circadian rhythms, aging attenuation, and life-span extension in mammals.

Oren Froy (The Hebrew University of Jerusalem Institute of Biochemistry, Food Science and Nutrition)

2011-08-01

34

Indy gene variation in natural populations confers fitness advantage and life span extension through transposon insertion  

PubMed Central

Natural selection acts to maximize reproductive fitness. However, antagonism between life span and reproductive success frequently poses a dilemma pitting the cost of fecundity against longevity. Here, we show that natural populations of Drosophila melanogaster harbor a Hoppel transposon insertion variant in the longevity gene Indy (I'm not dead yet), which confers both increased reproduction and longevity through metabolic changes. Heterozygosity for this natural long-lived variant has been maintained in isolates despite long-term inbreeding under laboratory conditions and advantageously confers increased fecundity. DNA sequences of variant chromosome isolates show evidence of selective sweep acting on the advantageous allele, suggesting that natural selection acts to maintain this variant. The transposon insertion also regulates Indy expression level, which has experimentally been shown to affect life span and fecundity. Thus, in the wild, evolution reaffirms that the mechanism of heterozygote advantage has acted upon the Indy gene to assure increased reproductive fitness and, coincidentally, longer life span through regulatory transposon mutagenesis.

Zhu, Chen-Tseh; Chang, Chengyi; Reenan, Robert A.; Helfand, Stephen L.

2014-01-01

35

Understanding Aggressive Behavior Across the Life Span  

PubMed Central

Aggressive behavior is the observable manifestation of aggression and is often associated with developmental transitions and a range of medical and psychiatric diagnoses across the lifespan. As healthcare professionals involved in the medical and psychosocial care of patients from birth through death, nurses frequently encounter—and may serve as—both victims and perpetrators of aggressive behavior in the workplace. While the nursing literature has continually reported research on prevention and treatment approaches, less emphasis has been given to understanding the etiology, including contextual precipitants of aggressive behavior. This paper provides a brief review of the biological, social, and environmental risk factors that purportedly give rise to aggressive behavior. Further, many researchers have focused specifically on aggressive behavior in adolescence and adulthood. Less attention has been given to understanding the etiology of such behavior in young children and older adults. This paper emphasizes the unique risk factors for aggressive behavior across the developmental spectrum, including childhood, adolescence, adulthood, and late life. Appreciation of the risk factors of aggressive behavior, and, in particular, how they relate to age-specific manifestations, can aid nurses in better design and implementation of prevention and treatment programs.

Liu, Jianghong; Lewis, Gary; Evans, Lois

2012-01-01

36

Human Needs: A Literature Review and Cognitive Life Span Model.  

National Technical Information Service (NTIS)

This paper reviews major theories of human needs and proposes a cognitive life span model, which may be applicable to Navy quality of life programs and policies. Five major needs theories are reviewed. Maslow's Hierarchy of Needs, Alderfer's ERG Theory, M...

P. Rosenfeld A. L. Culbertson P. Magnusson

1992-01-01

37

Longer life span evolves under high rates of condition-dependent mortality.  

PubMed

Aging affects nearly all organisms, but how aging evolves is still unclear. The central prediction of classic theory is that high extrinsic mortality leads to accelerated aging and shorter intrinsic life span. However, this prediction considers mortality as a random process, whereas mortality in nature is likely to be condition dependent. Therefore, the novel theory maintains that condition dependence may dramatically alter, and even reverse, the classic pattern. We present experimental evidence for the evolution of longer life span under high condition-dependent mortality. We employed an experimental evolution design, using a nematode, Caenorhabditis remanei, that allowed us to disentangle the effects of mortality rate (high versus low) and mortality source (random versus condition dependent). We observed the evolution of shorter life span under high random mortality, confirming the classic prediction. In contrast, high condition-dependent mortality led to the evolution of longer life span, supporting a key role of condition dependence in the evolution of aging. This life-span extension was not the result of a trade-off with reproduction. By simultaneously corroborating the classic results [8-10] and providing the first experimental evidence for the novel theory, our study resolves apparent contradictions in the study of aging and challenges the traditional paradigm by demonstrating that condition-environment interactions dictate the evolutionary trajectory of aging. PMID:23084993

Chen, Hwei-Yen; Maklakov, Alexei A

2012-11-20

38

Regulation of yeast replicative life span by thiol oxidoreductases  

PubMed Central

Thiol-based redox reactions are involved in the regulation of a variety of biological functions, such as protection against oxidative stress, signal transduction and protein folding. Some proteins involved in redox regulation have been shown to modulate life span in organisms from yeast to mammals. To assess the role of thiol oxidoreductases in aging on a genome-wide scale, we analyzed the replicative life span of yeast cells lacking known and candidate thiol oxidoreductases. The data suggest the role of several pathways in regulation of yeast aging, including thioredoxin reduction, protein folding and degradation, peroxide reduction, PIP3 signaling, and ATP synthesis.

Hacioglu, Elise; Esmer, Isil; Fomenko, Dmitri E.; Gladyshev, Vadim N.; Koc, Ahmet

2011-01-01

39

Decision-making heuristics and biases across the life span  

PubMed Central

We outline a contextual and motivational model of judgment and decision-making (JDM) biases across the life span. Our model focuses on abilities and skills that correspond to deliberative, experiential, and affective decision-making processes. We review research that addresses links between JDM biases and these processes as represented by individual differences in specific abilities and skills (e.g., fluid and crystallized intelligence, executive functioning, emotion regulation, personality traits). We focus on two JDM biases—the sunk-cost fallacy (SCF) and the framing effect. We trace the developmental trajectory of each bias from preschool through middle childhood, adolescence, early adulthood, and later adulthood. We conclude that life-span developmental trajectories differ depending on the bias investigated. Existing research suggests relative stability in the framing effect across the life span and decreases in the SCF with age, including in later life. We highlight directions for future research on JDM biases across the life span, emphasizing the need for process-oriented research and research that increases our understanding of JDM biases in people’s everyday lives.

Strough, JoNell; Karns, Tara E.; Schlosnagle, Leo

2013-01-01

40

Life Stress and Transitions in the Life Span  

Microsoft Academic Search

\\u000a The traditional life cycle of human beings include infancy, childhood, adolescence, and adulthood. Transitions exist within\\u000a each of the life cycles and such transitions produce stress. Life has many stressful life events that mark the movement from\\u000a one condition or cycle to another, and they produce substantial challenges in the lives of human beings. The purpose of this\\u000a volume is

Thomas W. Miller

41

Suicide Notes of Adolescents: A Life-span Comparison  

Microsoft Academic Search

Utilizing suicide notes as the data source, this study begins to explore some psychological dimensions in adolescent suicide and to identify the differences and similarities of suicide across the life span. The method called for 80 notes, representing four developmental ages (i.e., adolescents, young adults, middle adults, old adults) to be analyzed for specific protocols on eight categories, i.e., unbearable

Antoon A. Leenaars; Erik Jan De Wilde; Susanne Wenckstern; Michael Kral

2001-01-01

42

Minocycline Effect on Life and Health Span of Drosophila Melanogaster  

PubMed Central

Up-regulation of kynurenine (KYN) pathway of tryptophan (TRP) was suggested as one of the mechanisms of aging and aging-associated disorders. Genetic and pharmacological impairment of TRP – KYN metabolism resulted in prolongation of life span in Drosophila models. Minocycline, an antibiotic with anti-inflammatory, antioxidant and neuroprotective properties independent of its antibacterial activity, inhibited KYN formation from TRP. Since minocycline is the only FDA approved for human use medication with inhibitory effect on TRP – KYN metabolism, we were interested to study minocycline effect on life- and health-spans in Drosophila model. Minocycline (0.87mM) prolonged mean, median and maximum life span of wild-type Oregon Drosophila melanogaster of both genders. Minocycline (0.87 mM) stimulated vertical climbing in male flies. Minocycline dose-dependently decreased quantity and survivorship of pupae of filial generation. Minocycline might be a promising candidate drug for anti-aging intervention and treatment of aging-associated medical and psychiatric disorders. The role of TRP – KYN metabolism in the mechanisms of minocycline-effect on life- and health-span might be elucidated by the future assessment of minocycline effects in Drosophila mutants naturally or artificially knockout for genes impacting the key enzymes of KYN pathway of TRP metabolism.

Oxenkrug, Gregory; Navrotskaya, Valeriya; Vorobyova, Lyudmila; Summergrad, Paul

2012-01-01

43

Body image across the adult life span: stability and change  

Microsoft Academic Search

By far, the majority of studies investigating body image in adults have drawn samples from college populations within a very narrow age range. The purpose of the present paper is to review empirical research on the body image of adults older than the typical college student. There are marked changes in appearance across the adult life span, especially for women,

Marika Tiggemann

2004-01-01

44

Studies of Life Span Dietary Sodium Chloride Toxicity in Animals.  

National Technical Information Service (NTIS)

The objective of the research was to determine whether consistent, significant differences in response to life span dietary sodium chloride levels occur in dogs, and, if so, the influence of sex and genetics and exploration of the significance in the occu...

J. B. Youmans

1967-01-01

45

Neuromodulation of Behavioral and Cognitive Development across the Life Span  

ERIC Educational Resources Information Center

Among other mechanisms, behavioral and cognitive development entail, on the one hand, contextual scaffolding and, on the other hand, neuromodulation of adaptive neurocognitive representations across the life span. Key brain networks underlying cognition, emotion, and motivation are innervated by major transmitter systems (e.g., the catecholamines…

Li, Shu-Chen

2012-01-01

46

Fundamental frequency changes of persian speakers across the life span.  

PubMed

This study was designed to investigate changes in fundamental frequency (F0) across the life span in Persian speakers. Four hundred children and adults were asked to produce a sustained phonation of vowel /a/ and their voice samples were studied in 10 age groups. F0 was analyzed using the software Praat (Version 5.1.17.). The results revealed that (1) the mean F0 in both sexes decreases from childhood to adulthood; (2) significant F0 differences between boys and girls begin at the age of 12 years; and (3) the range of F0 changes in the life span is greater in men (178.38Hz) than in women (113.57Hz). These findings provide new data for Persian-speaking children, women, and men and could be beneficial for Iranian speech and language pathologists. PMID:24461477

Soltani, Majid; Ashayeri, Hasan; Modarresi, Yahya; Salavati, Mahyar; Ghomashchi, Hamed

2014-05-01

47

Rapamycin extends life- and health span because it slows aging.  

PubMed

Making headlines, a thought-provocative paper by Neff, Ehninger and coworkers claims that rapamycin extends life span but has limited effects on aging. How is that possibly possible? And what is aging if not an increase of the probability of death with age. I discuss that the JCI paper actually shows that rapamycin slows aging and also extends lifespan regardless of its direct anti-cancer activities. Aging is, in part, MTOR-driven: a purposeless continuation of developmental growth. Rapamycin affects the same processes in young and old animals: young animals' traits and phenotypes, which continuations become hyperfunctional, harmful and lethal later in life. PMID:23934728

Blagosklonny, Mikhail V

2013-08-01

48

Rapamycin extends life- and health span because it slows aging  

PubMed Central

Making headlines, a thought-provocative paper by Neff, Ehninger and coworkers claims that rapamycin extends life span but has limited effects on aging. How is that possibly possible? And what is aging if not an increase of the probability of death with age. I discuss that the JCI paper actually shows that rapamycin slows aging and also extends lifespan regardless of its direct anti-cancer activities. Aging is, in part, MTOR-driven: a purposeless continuation of developmental growth. Rapamycin affects the same processes in young and old animals: young animals' traits and phenotypes, which continuations become hyperfunctional, harmful and lethal later in life.

Blagosklonny, Mikhail V.

2013-01-01

49

Homeless Aging Veterans in Transition: A Life-Span Perspective  

PubMed Central

The need for counseling and career/educational services for homeless veterans has captured political and economic venues for more than 25 years. Veterans are three times more likely to become homeless than the general population if veterans live in poverty or are minority veterans. This mixed methods study emphasized a life-span perspective approach for exploring factors influencing normative aging and life-quality of 39 homeless veterans in Alabama and Florida. Seven descriptive quantitative and qualitative research questions framed the investigation. Study participants completed a quantitative survey reflecting their preferences and needs with a subset of the sample (N = 12) also participating in individual qualitative interview sessions. Thirty-two service providers and stakeholders completed quantitative surveys. Empirical and qualitative data with appropriate triangulation procedures provided interpretive information relative to a life-span development perspective. Study findings provide evidence of the need for future research efforts to address strategies that focus on the health and economic challenges of veterans before they are threatened with the possibility of homelessness. Implications of the study findings provide important information associated with the premise that human development occurs throughout life with specific characteristics influencing the individual's passage. Implications for aging/homelessness research are grounded in late-life transitioning and human development intervention considerations.

Thompson, Carla J.; Bridier, Nancy L.

2013-01-01

50

Homeless aging veterans in transition: a life-span perspective.  

PubMed

The need for counseling and career/educational services for homeless veterans has captured political and economic venues for more than 25 years. Veterans are three times more likely to become homeless than the general population if veterans live in poverty or are minority veterans. This mixed methods study emphasized a life-span perspective approach for exploring factors influencing normative aging and life-quality of 39 homeless veterans in Alabama and Florida. Seven descriptive quantitative and qualitative research questions framed the investigation. Study participants completed a quantitative survey reflecting their preferences and needs with a subset of the sample (N = 12) also participating in individual qualitative interview sessions. Thirty-two service providers and stakeholders completed quantitative surveys. Empirical and qualitative data with appropriate triangulation procedures provided interpretive information relative to a life-span development perspective. Study findings provide evidence of the need for future research efforts to address strategies that focus on the health and economic challenges of veterans before they are threatened with the possibility of homelessness. Implications of the study findings provide important information associated with the premise that human development occurs throughout life with specific characteristics influencing the individual's passage. Implications for aging/homelessness research are grounded in late-life transitioning and human development intervention considerations. PMID:24286010

Thompson, Carla J; Bridier, Nancy L

2013-01-01

51

Biotic feedback extends the life span of the biosphere  

NASA Astrophysics Data System (ADS)

The Sun is becoming more luminous with time and will eventually overheat the biosphere. However, life cools the Earth by amplifying the rate of silicate rock weathering and maintaining a low level of atmospheric CO2. Recent studies indicate a much stronger biotic weathering effect than in models used to estimate the life span of the biosphere. Here we show that the resulting feedback lengthens the survival of complex life by delaying the loss of CO2 from the atmosphere. The weathering biota can potentially maintain the Earth in a habitable state when otherwise it would be too hot for them. If so, catastrophic warming rather than gradual CO2 starvation will terminate complex life. Despite the possibility of an irreversible collapse, the current biosphere should remain resilient to carbon cycle perturbation or mass extinction events for at least 0.8 Gyr and may survive for up to 1.2 Gyr.

Lenton, Timothy M.; von Bloh, Werner

2001-05-01

52

The Life Cycle and Life Span of Namibian Fairy Circles  

PubMed Central

In Namibia of southwestern Africa, the sparse grasslands that develop on deep sandy soils under rainfall between 50 and 100 mm per annum are punctuated by thousands of quasi-circular bare spots, usually surrounded by a ring of taller grass. The causes of these so-called “fairy circles” are unknown, although a number of hypotheses have been proposed. This paper provides a more complete description of the variation in size, density and attributes of fairy circles in a range of soil types and situations. Circles are not permanent; their vegetative and physical attributes allow them to be arranged into a life history sequence in which circles appear (birth), develop (mature) and become revegetated (die). Occasionally, they also enlarge. The appearance and disappearance of circles was confirmed from satellite images taken 4 years apart (2004, 2008). The frequency of births and deaths as a fraction of the total population of circles allowed the calculation of an approximate turnover rate, and from this, an estimate of circle lifespan. Lifespan appeared to vary with circle size, with small circles averaging about 24 years, and larger ones 43–75 years. Overall lifespan averaged about 41 yr. A second, independent estimate of lifespan was made by revisiting circles 2 to 9 years after their clear status had been confirmed. This resulted in a lifespan estimate of about 60 years. Any causal explanation of fairy circles must include their birth, development and death, their mean lifespan and the variation of their features under different conditions.

Tschinkel, Walter R.

2012-01-01

53

C. elegans VANG-1 Modulates Life Span via Insulin/IGF-1-Like Signaling  

PubMed Central

The planar cell polarity (PCP) pathway is highly conserved from Drosophila to humans and a PCP-like pathway has recently been described in the nematode Caenorhabditis elegans. The developmental function of this pathway is to coordinate the orientation of cells or structures within the plane of an epithelium or to organize cell-cell intercalation required for correct morphogenesis. Here, we describe a novel role of VANG-1, the only C. elegans ortholog of the conserved PCP component Strabismus/Van Gogh. We show that two alleles of vang-1 and depletion of the protein by RNAi cause an increase of mean life span up to 40%. Consistent with the longevity phenotype vang-1 animals also show enhanced resistance to thermal- and oxidative stress and decreased lipofuscin accumulation. In addition, vang-1 mutants show defects like reduced brood size, decreased ovulation rate and prolonged reproductive span, which are also related to gerontogenes. The germline, but not the intestine or neurons, seems to be the primary site of vang-1 function. Life span extension in vang-1 mutants depends on the insulin/IGF-1-like receptor DAF-2 and DAF-16/FoxO transcription factor. RNAi against the phase II detoxification transcription factor SKN-1/Nrf2 also reduced vang-1 life span that might be explained by gradual inhibition of insulin/IGF-1-like signaling in vang-1. This is the first time that a key player of the PCP pathway is shown to be involved in the insulin/IGF-1-like signaling dependent modulation of life span in C. elegans.

Honnen, Sebastian J.; Buchter, Christian; Schroder, Verena; Hoffmann, Michael; Kohara, Yuji; Kampkotter, Andreas; Bossinger, Olaf

2012-01-01

54

AgRP-deficiency could lead to increased life span  

PubMed Central

The Agouti-related protein (AgRP) is a central orexigenic peptide leading to increased food intake when ubiquitously overexpressed. AgRP-deficient (AgRP?/?) mice have either no phenotype or present an age-related leanness. In this study, AgRP?/? mice were fed alternate high fat or low fat diets in an effort to determine whether AgRP is a mediating factor for the effects of dietary fat on metabolic parameters. There were no striking metabolic differences between AgRP?/? and the equally obese wild type littermates but AgRP?/? mice displayed a significantly longer life span. The point estimate of median survival for the AgRP?/? group was 9.8% greater while the significantly low hazard ratio (0.494) suggests that mortality incidence of AgRP?/? mice is less than one-half that of the wild type reference population. It is concluded that although AgRP?/? mice become morbidly obese consuming a high fat diet (a landmark feature for a shortened life span), they seem to overcome obesity- and age-related patholologies and live significantly longer than their metabolically similar wild type littermates.

Redmann, Stephen M.; Argyropoulos, George

2006-01-01

55

Extending Healthy Life SpanâÂÂFrom Yeast to Humans  

NSDL National Science Digital Library

When the food intake of organisms such as yeast and rodents is reduced (dietary restriction), they live longer than organisms fed a normal diet. A similar effect is seen when the activity of nutrient-sensing pathways is reduced by mutations or chemical inhibitors. In rodents, both dietary restriction and decreased nutrient-sensing pathway activity can lower the incidence of age-related loss of function and disease, including tumors and neurodegeneration. Dietary restriction also increases life span and protects against diabetes, cancer, and cardiovascular disease in rhesus monkeys, and in humans it causes changes that protect against these age-related pathologies. Tumors and diabetes are also uncommon in humans with mutations in the growth hormone receptor, and natural genetic variants in nutrient-sensing pathways are associated with increased human life span. Dietary restriction and reduced activity of nutrient-sensing pathways may thus slow aging by similar mechanisms, which have been conserved during evolution. We discuss these findings and their potential application to prevention of age-related disease and promotion of healthy aging in humans, and the challenge of possible negative side effects.

Luigi Fontana (Washington University School of Medicine/Istituto Superiore di Sanità;Division of Geriatrics and Nutritional Science/Division of Nutrition and Aging); Linda Partridge (University College London;3Institute of Healthy Aging, and G.E.E.); Valter Longo (University of Southern California;Andrus Gerontology Center and Department of Biological Sciences)

2010-04-16

56

AMPK?1 Deletion Shortens Erythrocyte Life Span in Mice  

PubMed Central

AMP-activated protein kinase (AMPK) is an energy sensor essential for maintaining cellular energy homeostasis. Here, we report that AMPK?1 is the predominant isoform of AMPK in murine erythrocytes and mice globally deficient in AMPK?1 (AMPK?1?/?), but not in those lacking AMPK?2, and the mice had markedly enlarged spleens with dramatically increased proportions of Ter119-positive erythroid cells. Blood tests revealed significantly decreased erythrocyte and hemoglobin levels with increased reticulocyte counts and elevated plasma erythropoietin concentrations in AMPK?1?/? mice. The life span of erythrocytes from AMPK?1?/? mice was less than that in wild-type littermates, and the levels of reactive oxygen species and oxidized proteins were significantly increased in AMPK?1?/? erythrocytes. In keeping with the elevated oxidative stress, treatment of AMPK?1?/? mice with the antioxidant, tempol, resulted in decreased reticulocyte counts and improved erythrocyte survival. Furthermore, the expression of Foxo3 and reactive oxygen species scavenging enzymes was significantly decreased in erythroblasts from AMPK?1?/? mice. Collectively, these results establish an essential role for AMPK?1 in regulating oxidative stress and life span in erythrocytes.

Wang, Shaobin; Dale, George L.; Song, Ping; Viollet, Benoit; Zou, Ming-hui

2010-01-01

57

SNEV overexpression extends the life span of human endothelial cells  

SciTech Connect

In a recent screening for genes downregulated in replicatively senescent human umbilical vein endothelial cells (HUVECs), we have isolated the novel protein SNEV. Since then SNEV has proven as a multifaceted protein playing a role in pre-mRNA splicing, DNA repair, and the ubiquitin/proteosome system. Here, we report that SNEV mRNA decreases in various cell types during replicative senescence, and that it is increased in various immortalized cell lines, as well as in breast tumors, where SNEV transcript levels also correlate with the survival of breast cancer patients. Since these mRNA profiles suggested a role of SNEV in the regulation of cell proliferation, the effect of its overexpression was tested. Thereby, a significant extension of the cellular life span was observed, which was not caused by altered telomerase activity or telomere dynamics but rather by enhanced stress resistance. When SNEV overexpressing cells were treated with bleomycin or bleomycin combined with BSO, inducing DNA damage as well as reactive oxygen species, a significantly lower fraction of apoptotic cells was found in comparison to vector control cells. These data suggest that high levels of SNEV might extend the cellular life span by increasing the resistance to stress or by improving the DNA repair capacity of the cells.

Voglauer, Regina [Institute of Applied Microbiology, Department of Biotechnology, University of Natural Resources and Applied Life Sciences Muthgasse 18, A-1190 Vienna (Austria); Chang, Martina Wei-Fen [Institute of Applied Microbiology, Department of Biotechnology, University of Natural Resources and Applied Life Sciences Muthgasse 18, A-1190 Vienna (Austria); Dampier, Brigitta [Department of Obstetrics and Gynecology, Medical University of Vienna, A-1090 Vienna (Austria); Wieser, Matthias [Institute of Applied Microbiology, Department of Biotechnology, University of Natural Resources and Applied Life Sciences Muthgasse 18, A-1190 Vienna (Austria); Baumann, Kristin [Institute of Applied Microbiology, Department of Biotechnology, University of Natural Resources and Applied Life Sciences Muthgasse 18, A-1190 Vienna (Austria); Sterovsky, Thomas [Institute of Applied Microbiology, Department of Biotechnology, University of Natural Resources and Applied Life Sciences Muthgasse 18, A-1190 Vienna (Austria); Schreiber, Martin [Department of Obstetrics and Gynecology, Medical University of Vienna, A-1090 Vienna (Austria); Katinger, Hermann [Institute of Applied Microbiology, Department of Biotechnology, University of Natural Resources and Applied Life Sciences Muthgasse 18, A-1190 Vienna (Austria); Grillari, Johannes [Institute of Applied Microbiology, Department of Biotechnology, University of Natural Resources and Applied Life Sciences Muthgasse 18, A-1190 Vienna (Austria) and BMT Research Vienna (Austria)]. E-mail: j.grillari@iam.boku.ac.at

2006-04-01

58

Sperm, Semen Defects May Be Linked to Shorter Life Spans  

MedlinePLUS

... reported in the May 16 online issue of Human Reproduction . Knowing this, doctors who treat men for infertility ... Mount Sinai, New York City; May 16, 2014, Human Reproduction , online HealthDay Copyright (c) 2014 HealthDay . All rights ...

59

Reproductive longevity and increased life expectancy  

Microsoft Academic Search

Background: female life expectancy in developed countries has increased by 30 years in the twentieth century. Aim: to determine if there has been an increase in reproductive longevity. Methods: we analysed age-specific fertility data from birth statistics for the USA, Canada, Japan, France, Sweden, the UK and Australia. Results: since 1940, birth rates for women aged 35 and over have

JACOB A. BRODY; M ARK D. GRANT; L AWRENCE J. FRATESCHI; SUSAN C. MILLER

60

Quantitative and Molecular Genetic Analyses of Mutations Increasing Drosophila Life Span  

PubMed Central

Understanding the genetic and environmental factors that affect variation in life span and senescence is of major interest for human health and evolutionary biology. Multiple mechanisms affect longevity, many of which are conserved across species, but the genetic networks underlying each mechanism and cross-talk between networks are unknown. We report the results of a screen for mutations affecting Drosophila life span. One third of the 1,332 homozygous P–element insertion lines assessed had quantitative effects on life span; mutations reducing life span were twice as common as mutations increasing life span. We confirmed 58 mutations with increased longevity, only one of which is in a gene previously associated with life span. The effects of the mutations increasing life span were highly sex-specific, with a trend towards opposite effects in males and females. Mutations in the same gene were associated with both increased and decreased life span, depending on the location and orientation of the P–element insertion, and genetic background. We observed substantial—and sex-specific—epistasis among a sample of ten mutations with increased life span. All mutations increasing life span had at least one deleterious pleiotropic effect on stress resistance or general health, with different patterns of pleiotropy for males and females. Whole-genome transcript profiles of seven of the mutant lines and the wild type revealed 4,488 differentially expressed transcripts, 553 of which were common to four or more of the mutant lines, which include genes previously associated with life span and novel genes implicated by this study. Therefore longevity has a large mutational target size; genes affecting life span have variable allelic effects; alleles affecting life span exhibit antagonistic pleiotropy and form epistatic networks; and sex-specific mutational effects are ubiquitous. Comparison of transcript profiles of long-lived mutations and the control line reveals a transcriptional signature of increased life span.

Magwire, Michael M.; Yamamoto, Akihiko; Carbone, Mary Anna; Roshina, Natalia V.; Symonenko, Alexander V.; Pasyukova, Elena G.; Morozova, Tatiana V.; Mackay, Trudy F. C.

2010-01-01

61

Concise Review: Hematopoietic Stem Cell Aging, Life Span, and Transplantation  

PubMed Central

Self-renewal and multilineage differentiation of stem cells are keys to the lifelong homeostatic maintenance of tissues and organs. Hematopoietic aging, characterized by immunosenescence, proinflammation, and anemia, is attributed to age-associated changes in the number and function of hematopoietic stem cells (HSCs) and their microenvironmental niche. Genetic variants and factors regulating stem cell aging are correlatively or causatively associated with overall organismal aging and longevity. Translational use of HSCs for transplantation and gene therapy demands effective methods for stem cell expansion. Targeting the molecular pathways involved in HSC self-renewal, proliferation, and homing has led to enhanced expansion and engraftment of stem cells upon transplantation. HSC transplantation is less effective in elderly people, even though this is the demographic with the greatest need for this form of treatment. Thus, understanding the biological changes in the aging of stem cells as well as local and systematic environments will improve the efficacy of aged stem cells for regenerative medicine and ultimately facilitate improved health and life spans.

Van Zant, Gary

2012-01-01

62

Colour constancy across the life span: evidence for compensatory mechanisms.  

PubMed

It is well known that the peripheral visual system declines with age: the yellowing of the lens causes a selective reduction of short-wavelength light and sensitivity losses occur in the cone receptor mechanisms. At the same time, our subjective experience of colour does not change with age. The main purpose of this large-scale study (n?=?185) covering a wide age range of colour-normal observers (18-75 years of age) was to assess the extent to which the human visual system is able to compensate for the changes in the optical media and at which level of processing this compensation is likely to occur. We report two main results: (1) Supra-threshold parafoveal colour perception remains largely unaffected by the age-related changes in the optical media (yellowing of the lens) whereas our ability to discriminate between small colour differences is compromised with an increase in age. (2) Significant changes in colour appearance are only found for unique green settings under daylight viewing condition which is consistent with the idea that the yellow-blue mechanism is most affected by an increase in age due to selective attenuation of short-wavelength light. The data on the invariance of hue perception, in conjunction with the age-related decline in chromatic sensitivity, provides evidence for compensatory mechanisms that enable colour-normal human observers a large degree of colour constancy across the life span. These compensatory mechanisms are likely to originate at cortical sites. PMID:23667689

Wuerger, Sophie

2013-01-01

63

Effects of calorie restriction on life span of microorganisms  

PubMed Central

Calorie restriction (CR) in microorganisms such as budding and fission yeasts has a robust and well-documented impact on longevity. In order to efficiently utilize the limited energy during CR, these organisms shift from primarily fermentative metabolism to mitochondrial respiration. Respiration activates certain conserved longevity factors such as sirtuins and is associated with widespread physiological changes that contribute to increased survival. However, the importance of respiration during CR-mediated longevity has remained controversial. The emergence of several novel metabolically distinct microbial models for longevity has enabled CR to be studied from new perspectives. The majority of CR and life span studies have been conducted in the primarily fermentative Crabtree-positive yeasts Saccharomyces cerevisiae and Schizosaccharomyces pombe, but studies in primarily respiratory Crabtree-negative yeast and obligate aerobes can offer complementary insight into the more complex mammalian response to CR. Not only are microorganisms helping characterize a conserved cellular mechanism for CR-mediated longevity, but they can also directly impact mammalian metabolism as part of the natural gut flora. Here, we discuss the contributions of microorganisms to our knowledge of CR and longevity at the level of both the cell and the organism.

Skinner, Craig

2010-01-01

64

Mice generated by in vitro fertilization exhibit vascular dysfunction and shortened life span  

PubMed Central

Children conceived by assisted reproductive technologies (ART) display a level of vascular dysfunction similar to that seen in children of mothers with preeclamspia. The long-term consequences of ART-associated vascular disorders are unknown and difficult to investigate in healthy children. Here, we found that vasculature from mice generated by ART display endothelial dysfunction and increased stiffness, which translated into arterial hypertension in vivo. Progeny of male ART mice also exhibited vascular dysfunction, suggesting underlying epigenetic modifications. ART mice had altered methylation at the promoter of the gene encoding eNOS in the aorta, which correlated with decreased vascular eNOS expression and NO synthesis. Administration of a deacetylase inhibitor to ART mice normalized vascular gene methylation and function and resulted in progeny without vascular dysfunction. The induction of ART-associated vascular and epigenetic alterations appeared to be related to the embryo environment; these alterations were possibly facilitated by the hormonally stimulated ovulation accompanying ART. Finally, ART mice challenged with a high-fat diet had roughly a 25% shorter life span compared with control animals. This study highlights the potential of ART to induce vascular dysfunction and shorten life span and suggests that epigenetic alterations contribute to these problems.

Rexhaj, Emrush; Paoloni-Giacobino, Ariane; Rimoldi, Stefano F.; Fuster, Daniel G.; Anderegg, Manuel; Somm, Emmanuel; Bouillet, Elisa; Allemann, Yves; Sartori, Claudio; Scherrer, Urs

2013-01-01

65

Brief Report: A Life-Span Perspective on the Development of Individuals with Autism.  

ERIC Educational Resources Information Center

This discussion of planning for individuals with autism using a life-span perspective considers stages and transitions across life, noting the special difficulty these individuals have with transitions; changing perspectives on disability in the United States; and characteristics of comprehensive life-span programs (sophisticated diagnoses, strong…

Schroeder, Stephen R.; And Others

1996-01-01

66

[Aging and life-history: aims and approaches to a life-span oriented gerontology].  

PubMed

The paper discusses the contributions of American theoretical and empirical approaches in life span developmental psychology to the understand of aging in a life-span frame of reference. The main part of the paper consists of a report on longitudinal as well as biographical studies on psychological and social development in adolescence, middle, and late adulthood which started at the Psychology Department of the University of Bonn in 1952 and are continued into the 80's. These studies point to close relationships between the social and psychological conditions in earlier and later periods of life and stress the relevance of promoting not only mental, but also social and effective-emotional competence for the coping with crisis situation in old age. PMID:7008405

Thomae, H

1980-01-01

67

Life history theory and human reproductive behavior  

Microsoft Academic Search

The purpose of this article is to develop a model of life history theory that incorporates environmental influences, contextual\\u000a influences, and heritable variation. I argue that physically or psychologically stressful environments delay maturation and\\u000a the onset of reproductive competence. The social context is also important, and here I concentrate on the opportunity for\\u000a upward social mobility as a contextual influence

Kevin MacDonald; California State

1997-01-01

68

Reproduction: life cycle, larvae and larviculture.  

PubMed

Nephrops norvegicus represents a very valuable fishery across Europe, and the species possesses a relatively complex life cycle and reproductive biology across spatial and temporal scales. Insights into embryonic and larval biology, and associated abiotic and biotic factors that influence recruitment, are important since this will affect population and species success. Much of the fishery, and indeed scientific sampling, is reliant on trawling, which is likely to cause direct and indirect stresses on adults and developing embryos. We have collated evidence, including that garnered from laboratory studies, to assess the likely effects on reproduction and population. Using know-how from hatchery operations in similar species such as Homarus sp., we also seek to optimise larviculture that could be commercialised to create a hatchery and thus assist stock remediation. This review chapter is therefore divided into three sections: (1) general N. norvegicus reproductive biology, (2) life cycle and larval biology and (3) a comprehensive review of all rearing attempts for this species to date, including a likely way forward for pilot scale and hence commercial restocking operations. PMID:23668591

Powell, Adam; Eriksson, Susanne P

2013-01-01

69

Qualitative Exploration of Acculturation and Life-Span Issues of Elderly Asian Americans  

ERIC Educational Resources Information Center

Awareness of aging issues across diverse populations begins the journey toward counselors becoming culturally competent across client life spans. Understanding the life-span experiences of cultural groups is important for helping professionals. The purpose of this research was to gain insight into the qualitative experiences of Asian American…

Lee, Jee Hyang; Heo, Nanseol; Lu, Junfei; Portman, Tarrell Awe Agahe

2013-01-01

70

The Rate of Source Memory Decline across the Adult Life Span  

ERIC Educational Resources Information Center

Previous studies have suggested that the ability to remember contextual information related to specific episodic experiences declines with advancing age; however, the exact moment in the adult life span when this deficit begins is still controversial. Source memory for spatial information was tested in a life span sample of 1,500 adults between…

Cansino, Selene; Estrada-Manilla, Cinthya; Hernandez-Ramos, Evelia; Martinez-Galindo, Joyce Graciela; Torres-Trejo, Frine; Gomez-Fernandez, Tania; Ayala-Hernandez, Mariana; Osorio, David; Cedillo-Tinoco, Melisa; Garces-Flores, Lissete; Gomez-Melgarejo, Sandra; Beltran-Palacios, Karla; Guadalupe Garcia-Lazaro, Haydee; Garcia-Gutierrez, Fabiola; Cadena-Arenas, Yadira; Fernandez-Apan, Luisa; Bartschi, Andrea; Resendiz-Vera, Julieta; Rodriguez-Ortiz, Maria Dolores

2013-01-01

71

The Time of Our Lives: Life Span Development of Timing and Event Tracking  

ERIC Educational Resources Information Center

Life span developmental profiles were constructed for 305 participants (ages 4-95) for a battery of paced and unpaced perceptual-motor timing tasks that included synchronize-continue tapping at a wide range of target event rates. Two life span hypotheses, derived from an entrainment theory of timing and event tracking, were tested. A preferred…

McAuley, J. Devin; Jones, Mari Riess; Holub, Shayla; Johnston, Heather M.; Miller, Nathaniel S.

2006-01-01

72

Exploratory and problem-solving consumer behavior across the life span.  

PubMed

Different cognitive functioning, social, and personality changes appear to occur systematically during the adult life span. This article synthesizes research on life span changes in order to develop age-specific models of shopping behavior. The models are tested within a naturalistic field study of shoppers. PMID:1890293

Lesser, J A; Kunkel, S R

1991-09-01

73

Genomic Instability Is Associated with Natural Life Span Variation in Saccharomyces cerevisiae  

PubMed Central

Increasing genomic instability is associated with aging in eukaryotes, but the connection between genomic instability and natural variation in life span is unknown. We have quantified chronological life span and loss-of-heterozygosity (LOH) in 11 natural isolates of Saccharomyces cerevisiae. We show that genomic instability increases and mitotic asymmetry breaks down during chronological aging. The age-dependent increase of genomic instability generally lags behind the drop of viability and this delay accounts for ?50% of the observed natural variation of replicative life span in these yeast isolates. We conclude that the abilities of yeast strains to tolerate genomic instability co-vary with their replicative life spans. To the best of our knowledge, this is the first quantitative evidence that demonstrates a link between genomic instability and natural variation in life span.

Qin, Hong; Lu, Meng; Goldfarb, David S.

2008-01-01

74

Personality and Obesity Across the Adult Life Span  

Microsoft Academic Search

Personality traits contribute to health outcomes, in part through their association with major controllable risk factors, such as obesity. Body weight, in turn, reflects our behaviors and lifestyle and contributes to the way we perceive ourselves and others. In this study, the authors use data from a large (N = 1,988) longitudinal study that spanned more than 50 years to

Angelina R. Sutin; Luigi Ferrucci; Alan B. Zonderman; Antonio Terracciano

2011-01-01

75

Induced overexpression of mitochondrial Mn-superoxide dismutase extends the life span of adult Drosophila melanogaster.  

PubMed Central

A transgenic system ("FLP-out") based on yeast FLP recombinase allowed induced overexpression of MnSOD enzyme in adult Drosophila melanogaster. With FLP-out a brief heat pulse (HP) of young, adult flies triggered the rearrangement and subsequent expression of a MnSOD transgene throughout the adult life span. Control (no HP) and overexpressing (HP) flies had identical genetic backgrounds. The amount of MnSOD enzyme overexpression achieved varied among six independent transgenic lines, with increases up to 75%. Life span was increased in proportion to the increase in enzyme. Mean life span was increased by an average of 16%, with some lines showing 30-33% increases. Maximum life span was increased by an average of 15%, with one line showing as much as 37% increase. Simultaneous overexpression of catalase with MnSOD had no added benefit, consistent with previous observations that catalase is present in excess in the adult fly with regard to life span. Cu/ZnSOD overexpression also increases mean and maximum life span. For both MnSOD and Cu/ZnSOD lines, increased life span was not associated with decreased metabolic activity, as measured by O2 consumption.

Sun, Jingtao; Folk, Donna; Bradley, Timothy J; Tower, John

2002-01-01

76

Continuity of the prototypes of social competence and shyness over the life span and across life transitions  

Microsoft Academic Search

The continuity of the prototypes of two personality traits, social competence and shyness, over the life span and across life transitions was studied. Teachers who were either familiar with children in a particular life phase, or who were themselves in a certain transitional or stable life phase, were asked to give a description of a prototypical socially competent person and

Marcel A. G. van Aken; Jens B. Asendorpf

1996-01-01

77

Increased expression of Drosophila Sir2 extends life span in a dose-dependent manner.  

PubMed

Sir2, a member of the sirtuin family of protein acylases, deacetylates lysine residues within many proteins and is associated with lifespan extension in a variety of model organisms. Recent studies have questioned the positive effects of Sir2 on lifespan inDrosophila. Several studies have shown that increased expression of the Drosophila Sir2 homolog (dSir2) extends life span while other studies have reported no effect on life span or suggested that increased dSir2 expression was cytotoxic. To attempt to reconcile the differences in these observed effects of dSir2 on Drosophila life span, we hypothesized that a critical level of dSir2 may be necessary to mediate life span extension. Using approaches that allow us to titrate dSir2 expression, we describe here a strong dose-dependent effect of dSir2 on life span. Using the two transgenic dSir2 lines that were reported not to extend life span, we are able to show significant life span extension when dSir2 expression is induced between 2 and 5-fold. However, higher levels decrease life span and can induce cellular toxicity, manifested by increased expression of the JNK-signaling molecule Puc phosphatase and induction of dnaJ-H. Our results help to resolve the apparently conflicting reports by demonstrating that the effects of increased dSir2 expression on life span in Drosophila are dependent upon dSir2 dosage. PMID:24036492

Whitaker, Rachel; Faulkner, Shakeela; Miyokawa, Reika; Burhenn, Lucas; Henriksen, Mark; Wood, Jason G; Helfand, Stephen L

2013-09-01

78

Personality and self-esteem development across the life span  

Microsoft Academic Search

Over the past few decades, there has been an explosion of longitudinal research on the consistency of personality and related constructs such as self-esteem. This plethora of studies has provided suKcient evidence to move researchers toward consensus about the degree to which personality characteristics change over the life course. The emerging story, based on an accumulating body of empirical research,

Kali H. Trzesniewski; Richard W. Robins; Brent W. Roberts; Avshalom Caspi

2003-01-01

79

Female Career Commitment (A Life-Span Perspective). Special Report.  

ERIC Educational Resources Information Center

A study that examined the personality and environmental factors affecting South African female career interest and career commitment at different life phases resulted in development of a model of vocational behavior. Selected for the study sample were 111 graduated white women employed by the Council for Scientific and Industrial Research. The…

van Rooyen, J.

80

Gene activities that mediate increased life span of C. elegans insulin-like signaling mutants.  

PubMed

Genetic and RNA interference (RNAi) screens for life span regulatory genes have revealed that the daf-2 insulin-like signaling pathway plays a major role in Caenorhabditis elegans longevity. This pathway converges on the DAF-16 transcription factor and may regulate life span by controlling the expression of a large number of genes, including free-radical detoxifying genes, stress resistance genes, and pathogen resistance genes. We conducted a genome-wide RNAi screen to identify genes necessary for the extended life span of daf-2 mutants and identified approximately 200 gene inactivations that shorten daf-2 life span. Some of these gene inactivations dramatically shorten daf-2 mutant life span but less dramatically shorten daf-2; daf-16 mutant or wild-type life span. Molecular and behavioral markers for normal aging and for extended life span in low insulin/IGF1 (insulin-like growth factor 1) signaling were assayed to distinguish accelerated aging from general sickness and to examine age-related phenotypes. Detailed demographic analysis, molecular markers of aging, and insulin signaling mutant test strains were used to filter progeric gene inactivations for specific acceleration of aging. Highly represented in the genes that mediate life span extension in the daf-2 mutant are components of endocytotic trafficking of membrane proteins to lysosomes. These gene inactivations disrupt the increased expression of the DAF-16 downstream gene superoxide dismutase sod-3 in a daf-2 mutant, suggesting trafficking between the insulin-like receptor and DAF-16. The activities of these genes may normally decline during aging. PMID:18006689

Samuelson, Andrew V; Carr, Christopher E; Ruvkun, Gary

2007-11-15

81

Extension of Life-Span by Loss of CHICO, a Drosophila Insulin Receptor Substrate Protein  

Microsoft Academic Search

The Drosophila melanogaster gene chico encodes an insulin receptor substrate that functions in an insulin\\/insulin-like growth factor (IGF) signaling pathway. In the nematode Caenorhabditis elegans, insulin\\/IGF signaling regulates adult longevity. We found that mutation of chico extends fruit fly median life-span by up to 48% in homozygotes and 36% in heterozygotes. Extension of life-span was not a result of impaired

David J. Clancy; David Gems; Lawrence G. Harshman; Sean Oldham; Hugo Stocker; Ernst Hafen; Sally J. Leevers; Linda Partridge

2001-01-01

82

Effect of BCL2 down-regulation on cellular life span  

Microsoft Academic Search

Reactive oxygen species (ROS) are toxic for cells. BCL-2 is known as the anti-death protein and acts as an antioxidant. When\\u000a theBCL-2 level of normal fibroblasts was suppressed by antisense bcl-2oligodeoxynucleotide or antisense bcl-2 RNA expression, the life span of the culture was shortened by about 11 population doublings(approx. 15% of the total life\\u000a span) in comparison to the control

Tsutomu Kumazaki; Masao Sasaki; Masahiko Nishiyama; Yasuhiro Teranishi; Hiroshi Sumida; Youji Mitsui

2002-01-01

83

Women and Bipolar Disorder Across the Life Span  

PubMed Central

Bipolar I disorder occurs in approximately 1% of the adult population, and it affects women and men, equally. Women develop bipolar II disorder, bipolar depression, mixed mania, and a rapid-cycling course of illness more commonly than men and are at greater risk of such comorbid conditions as alcohol use problems, thyroid disease, medication-induced obesity, and migraine headaches. The treatment of bipolar disorder remains challenging. Although lithium reduces symptoms and prevents recurrence with good efficacy, a significant number of patients stop taking it. Furthermore, several anticonvulsants and antidepressants are prescribed off label for acute episodes and prophylaxis despite the lack of adequate research support. Psychotherapy may alleviate mania or depression and improve treatment compliance, yet its ability to prevent relapse remains uncertain. Changes throughout the reproductive cycle also have an impact on the onset and presentation of bipolar symptoms and the choice of treatment. This article provides an overview of common presentations and comorbidities, along with approaches to evaluation and treatment of women with bipolar disorder.

Sit, Dorothy

2011-01-01

84

Adenosine nucleotide biosynthesis and AMPK regulate adult life span and mediate the longevity benefit of caloric restriction in flies.  

PubMed

A common thread among conserved life span regulators lies within intertwined roles in metabolism and energy homeostasis. We show that heterozygous mutations of AMP biosynthetic enzymes extend Drosophila life span. The life span benefit of these mutations depends upon increased AMP:ATP and ADP:ATP ratios and adenosine monophosphate-activated protein kinase (AMPK). Transgenic expression of AMPK in adult fat body or adult muscle, key metabolic tissues, extended life span, while AMPK RNAi reduced life span. Supplementing adenine, a substrate for AMP biosynthesis, to the diet of long-lived AMP biosynthesis mutants reversed life span extension. Remarkably, this simple change in diet also blocked the prolongevity effects of dietary restriction. These data establish AMP biosynthesis, adenosine nucleotide ratios, and AMPK as determinants of adult life span; provide a mechanistic link between cellular anabolism and energy sensing pathways; and indicate that dietary adenine manipulations might alter metabolism to influence animal life span. PMID:23312286

Stenesen, Drew; Suh, Jae Myoung; Seo, Jin; Yu, Kweon; Lee, Kyu-Sun; Kim, Jong-Seok; Min, Kyung-Jin; Graff, Jonathan M

2013-01-01

85

Disentangling environmental effects on adult life span in a butterfly across the metamorphic boundary.  

PubMed

Life span is a central life history trait often showing tremendous variation within populations. Much of this variation can be attributed to environmental factors. In holometabolous insects life stages differ strikingly in physiology and energetic demands, and environmental variation before and after metamorphosis may not necessarily yield identical responses. In this study, we adopted a full-factorial experimental design with two larval and two adult temperatures as well as two larval and three adult feeding treatments (n(total)=1151). Identical temperatures yielded qualitatively different results depending on the developmental stage. While the lower compared to the higher developmental temperature slightly reduced adult life span, a lower adult temperature substantially increased life span. Food stress in the larval stage slightly reduced life span, as did food stress during the adult stage. Females lived generally longer than males. All factors investigated were involved in interactions with other factors, both within and across life stages. For instance, the qualitative impact of larval food stress depended on adult feeding treatment and adult temperature. Our results suggest that much insight into the causes of variation in life span is to be gained by explicitly considering environmental impacts across developmental stages and potential interactions among different environmental factors. PMID:19836442

Bauerfeind, Stephanie S; Perlick, Jana E C; Fischer, Klaus

2009-12-01

86

[Survival and life span of Drosophila melanogaster in response to terahertz radiation].  

PubMed

Life span control is realized by an interaction of many genetic factors with environment. Due to development of new modern technologies based on non-ionized terahertz radiation (0,1-10 THz) the investigation of this radiation influence on living organisms becomes actual. In our study terahertz radiation effects on survival and life span of Oregon R line of Drosophila meanogaster were multidirectional depending on the age of the insects. Terahertz effect on survival was negative or neutral in the early life and positive in the later life. In Drosophila response to terahertz radiation sex differences were manifested. Males were not very sensitive to terahertz radiation. Irradiated female survival was increased significantly in the second half of imago life. Irradiation of Drosophila not influenced significantly on average and maximal values of life span, but the gap between the values of average life span of males and females in this group of insects was increased. Mechanisms of terahertz radiation effects on survival and life span maybe associated with changes in cellular membrane, gene expression and signaling pathways, controlling these properties. PMID:24738251

Va?sman, N Ia; Fedorov, V I; Nemova, E F; Nikolaev, N A

2013-01-01

87

Increased Life Span due to Calorie Restriction in Respiratory-Deficient Yeast  

PubMed Central

A model for replicative life span extension by calorie restriction (CR) in yeast has been proposed whereby reduced glucose in the growth medium leads to activation of the NAD+–dependent histone deacetylase Sir2. One mechanism proposed for this putative activation of Sir2 is that CR enhances the rate of respiration, in turn leading to altered levels of NAD+ or NADH, and ultimately resulting in enhanced Sir2 activity. An alternative mechanism has been proposed in which CR decreases levels of the Sir2 inhibitor nicotinamide through increased expression of the gene coding for nicotinamidase, PNC1. We have previously reported that life span extension by CR is not dependent on Sir2 in the long-lived BY4742 strain background. Here we have determined the requirement for respiration and the effect of nicotinamide levels on life span extension by CR. We find that CR confers robust life span extension in respiratory-deficient cells independent of strain background, and moreover, suppresses the premature mortality associated with loss of mitochondrial DNA in the short-lived PSY316 strain. Addition of nicotinamide to the medium dramatically shortens the life span of wild type cells, due to inhibition of Sir2. However, even in cells lacking both Sir2 and the replication fork block protein Fob1, nicotinamide partially prevents life span extension by CR. These findings (1) demonstrate that respiration is not required for the longevity benefits of CR in yeast, (2) show that nicotinamide inhibits life span extension by CR through a Sir2-independent mechanism, and (3) suggest that CR acts through a conserved, Sir2-independent mechanism in both PSY316 and BY4742.

2005-01-01

88

Worldwide Variation in Life-Span Sexual Dimorphism and Sex-Specific Environmental Mortality Rates  

Microsoft Academic Search

In all human populations mean life span of women generally exceeds that of men, but the extent of this sexual dimorphism varies across different regions of the world. Our purpose here is to study, using global demographic and environmental data, the general tendency of this variation and local deviations from it. We used data on male and female life history

Anatoly T. Teriokhin; Elena V. Budilova; Frederic Thomas; Jean-Francois Guegan

2004-01-01

89

Worldwide Variation in Life-Span Sexual Dimorphism and Sex-Specific Environmental Mortality Rates  

Microsoft Academic Search

In all human populations mean life span of women generally exceeds that of men, but the extent of this sexual dimorphism varies across different regions of the world. Our purpose here is to study, using global demographic and environmental data, the general tendency of this variation and local deviations from it. We used data on male and female life history

Anatoly T. Teriokhin; Elena V. Budilovo; Frederic Thomas; Jean-Francois Guegan

2011-01-01

90

Leaf traits and leaf life spans of two xeric-adapted palmettos.  

PubMed

Plants of nutrient-poor, arid environments often have leaf traits that include small size, sclerophylly, long life span, low nutrient concentration, and low photosynthetic rate. Hence, the success of two large-leaved palmettos in peninsular Florida's seasonally xeric, nutrient-impoverished uplands seems anomalous, given that their leaves are orders of magnitude larger than the leaves of sympatric species. An examination of a 16-yr data set of leaf traits and leaf life spans across four vegetative associations differing in available light showed that Serenoa repens and Sabal etonia had low rates of leaf production coupled with long leaf life spans reaching 3.5 yr in heavily shaded plants. The adaptation of these palmettos to xeric, nutrient-poor habitats has generated dwarf statures, diminished leaf sizes and numbers, increased leaf life spans, and reduced rates of leaf production relative to other palms and congeners of more mesic sites. Leaf and petiole size, plant leaf canopy area, and leaf life span increased in both palmettos with decreasing available light, helping to compensate for reduced photosynthetic rates under shaded conditions and for the high leaf construction costs of the large, thick palmetto leaves. Large leaf size in these palmettos, likely due to phylogenetic conservatism, is compensated by other leaf traits (e.g., heavily cutinized epidermises, thick laminas) that increase survival in seasonally xeric, nutrient-impoverished environments. PMID:21636496

Abrahamson, Warren G

2007-08-01

91

The Life Cycle in Historical Context: The Impact of Normative History-Graded Events on the Course of Life-Span Human Development.  

ERIC Educational Resources Information Center

Reviews papers presented at the Eighth West Virginia University Biennial Conference on Life-Span Development, which was intended to explore historical and generational (cohort) effects in life-span development.(Author/RH)

Simons, C.J.R.; Thomas, J.L.

1983-01-01

92

Life-span extension by a metacaspase in the yeast Saccharomyces cerevisiae.  

PubMed

Single-cell species harbor ancestral structural homologs of caspase proteases, although the evolutionary benefit of such apoptosis-related proteins in unicellular organisms is unclear. Here, we found that the yeast metacaspase Mca1 is recruited to the insoluble protein deposit (IPOD) and juxtanuclear quality-control compartment (JUNQ) during aging and proteostatic stress. Elevating MCA1 expression counteracted accumulation of unfolded proteins and aggregates and extended life span in a heat shock protein Hsp104 disaggregase- and proteasome-dependent manner. Consistent with a role in protein quality control, genetic interaction analysis revealed that MCA1 buffers against deficiencies in the Hsp40 chaperone YDJ1 in a caspase cysteine-dependent manner. Life-span extension and aggregate management by Mca1 was only partly dependent on its conserved catalytic cysteine, which suggests that Mca1 harbors both caspase-dependent and independent functions related to life-span control. PMID:24855027

Hill, Sandra Malmgren; Hao, Xinxin; Liu, Beidong; Nyström, Thomas

2014-06-20

93

Survival Analysis of Life Span Quantitative Trait Loci in Drosophila melanogaster  

PubMed Central

We used quantitative trait loci (QTL) mapping to evaluate the age specificity of naturally segregating alleles affecting life span. Estimates of age-specific mortality rates were obtained from observing 51,778 mated males and females from a panel of 144 recombinant inbred lines (RILs). Twenty-five QTL were found, having 80 significant effects on life span and weekly mortality rates. Generation of RILs from heterozygous parents enabled us to contrast effects of QTL alleles with the means of RIL populations. Most of the low-frequency alleles increased mortality, especially at younger ages. Two QTL had negatively correlated effects on mortality at different ages, while the remainder were positively correlated. Chromosomal positions of QTL were roughly concordant with estimates from other mapping populations. Our findings are broadly consistent with a mix of transient deleterious mutations and a few polymorphisms maintained by balancing selection, which together contribute to standing genetic variation in life span.

Nuzhdin, Sergey V.; Khazaeli, Aziz A.; Curtsinger, James W.

2005-01-01

94

Foraging across the life span: is there a reduction in exploration with aging?  

PubMed Central

Does foraging change across the life span, and in particular, with aging? We report data from two foraging tasks used to investigate age differences in search in external environments as well as internal search in memory. Overall, the evidence suggests that foraging behavior may undergo significant changes across the life span across internal and external search. In particular, we find evidence of a trend toward reduced exploration with increased age. We discuss these findings in light of theories that postulate a link between aging and reductions in novelty seeking and exploratory behavior.

Mata, Rui; Wilke, Andreas; Czienskowski, Uwe

2013-01-01

95

Reproductive and post-reproductive life history of wild-caught Drosophila melanogaster under laboratory conditions.  

PubMed

The life history of the fruit fly (Drosophila melanogaster) is well understood, but fitness components are rarely measured by following single individuals over their lifetime, thereby limiting insights into lifetime reproductive success, reproductive senescence and post-reproductive lifespan. Moreover, most studies have examined long-established laboratory strains rather than freshly caught individuals and may thus be confounded by adaptation to laboratory culture, inbreeding or mutation accumulation. Here, we have followed the life histories of individual females from three recently caught, non-laboratory-adapted wild populations of D. melanogaster. Populations varied in a number of life-history traits, including ovariole number, fecundity, hatchability and lifespan. To describe individual patterns of age-specific fecundity, we developed a new model that allowed us to distinguish four phases during a female's life: a phase of reproductive maturation, followed by a period of linear and then exponential decline in fecundity and, finally, a post-ovipository period. Individual females exhibited clear-cut fecundity peaks, which contrasts with previous analyses, and post-peak levels of fecundity declined independently of how long females lived. Notably, females had a pronounced post-reproductive lifespan, which on average made up 40% of total lifespan. Post-reproductive lifespan did not differ among populations and was not correlated with reproductive fitness components, supporting the hypothesis that this period is a highly variable, random 'add-on' at the end of reproductive life rather than a correlate of selection on reproductive fitness. Most life-history traits were positively correlated, a pattern that might be due to genotype by environment interactions when wild flies are brought into a novel laboratory environment but that is unlikely explained by inbreeding or positive mutational covariance caused by mutation accumulation. PMID:23675912

Klepsatel, P; Gáliková, M; De Maio, N; Ricci, S; Schlötterer, C; Flatt, T

2013-07-01

96

D-Glucosamine supplementation extends life span of nematodes and of ageing mice.  

PubMed

D-Glucosamine (GlcN) is a freely available and commonly used dietary supplement potentially promoting cartilage health in humans, which also acts as an inhibitor of glycolysis. Here we show that GlcN, independent of the hexosamine pathway, extends Caenorhabditis elegans life span by impairing glucose metabolism that activates AMP-activated protein kinase (AMPK/AAK-2) and increases mitochondrial biogenesis. Consistent with the concept of mitohormesis, GlcN promotes increased formation of mitochondrial reactive oxygen species (ROS) culminating in increased expression of the nematodal amino acid-transporter 1 (aat-1) gene. Ameliorating mitochondrial ROS formation or impairment of aat-1-expression abolishes GlcN-mediated life span extension in an NRF2/SKN-1-dependent fashion. Unlike other calorie restriction mimetics, such as 2-deoxyglucose, GlcN extends life span of ageing C57BL/6 mice, which show an induction of mitochondrial biogenesis, lowered blood glucose levels, enhanced expression of several murine amino-acid transporters, as well as increased amino-acid catabolism. Taken together, we provide evidence that GlcN extends life span in evolutionary distinct species by mimicking a low-carbohydrate diet. PMID:24714520

Weimer, Sandra; Priebs, Josephine; Kuhlow, Doreen; Groth, Marco; Priebe, Steffen; Mansfeld, Johannes; Merry, Troy L; Dubuis, Sébastien; Laube, Beate; Pfeiffer, Andreas F; Schulz, Tim J; Guthke, Reinhard; Platzer, Matthias; Zamboni, Nicola; Zarse, Kim; Ristow, Michael

2014-01-01

97

Asynchronous Vowel-Pair Identification across the Adult Life Span for Monaural and Dichotic Presentations  

ERIC Educational Resources Information Center

Purpose: Temporal order abilities decrease with age. Declining temporal processing abilities may influence the identification of rapid vowel sequences. Identification patterns for asynchronous vowel pairs were explored across the life span. Method: Young, middle-aged, and older listeners completed temporal order tasks for pairs of 70-ms and 40-ms…

Fogerty, Daniel; Kewley-Port, Diane; Humes, Larry E.

2012-01-01

98

?1-Adrenergic receptor blockade extends the life span of Drosophila and long-lived mice.  

PubMed

Chronic treatment with ?-adrenergic receptor (?AR) agonists increases mortality and morbidity while ?AR antagonists (?-blockers) decrease all-cause mortality for those at risk of cardiac disease. Levels of sympathetic nervous system ?AR agonists and ?AR activity increase with age, and this increase may hasten the development of age-related mortality. Here, we show that ?-blockers extend the life span of healthy metazoans. The ?-blockers metoprolol and nebivolol, administered in food daily beginning at 12 months of age, significantly increase the mean and median life span of isocalorically fed, male C3B6F1 mice, by 10 and 6.4%, respectively (P < 0.05). Neither drug affected the weight or food intake of the mice, indicating that induced CR is not responsible for these effects, and that energy absorption and utilization are not altered by the drugs. Both ?-blockers were investigated to control for their idiosyncratic, off-target effects. Metoprolol and nebivolol extended Drosophila life span, without affecting food intake or locomotion. Thus, ?AR antagonists are capable of directly extending the life span of two widely divergent metazoans, suggesting that these effects are phylogenetically highly conserved. Thus, long-term use of ?-blockers, which are generally well-tolerated, may enhance the longevity of healthy humans. PMID:23314750

Spindler, Stephen R; Mote, Patricia L; Li, Rui; Dhahbi, Joseph M; Yamakawa, Amy; Flegal, James M; Jeske, Daniel R; Li, Rui; Lublin, Alex L

2013-12-01

99

Age, growth and size interact with stress to determine life span and mortality  

PubMed Central

Individuals in a large experimental field population, of the short-lived perennial species Plantago lanceolata, were followed to determine the sources of variation that influence mortality and life span. The design included multiple age groups with initially similar genetic structure, which made it possible to separate age effects from period effects and to identify the genetic component to variation in life span. During a period of stress, individuals of all ages showed parallel increases in mortality but different cohorts experienced this period of high mortality at different ages. This then influenced the distribution of life spans across cohorts. Age and size-age interactions influenced mortality during the period of stress. Smaller individuals died but only if they were old. Additionally, growth and age interacted with stress such that older individuals had negative growth and high mortality whereas younger individuals had positive growth and relatively lower mortality during stress. The results of this study show that it is not simply the environment that can have a major impact on demography in natural populations, rather, age, size and growth can interact with the environment to influence mortality and life span when the environment is stressful.

Roach, Deborah Ann

2012-01-01

100

Chromosomal Instability and Telomere Length Variations during the Life Span of Human Fibroblast Clones  

Microsoft Academic Search

Growth characteristics, karyotype changes, and telomere length variations were analyzed during the life span of 12 anchorage-independent clones isolated from a xeroderma pigmentosum fibroblast strain. After an initial period of comparable active growth, all the clones showed a decline in the growth rate and finally entered a phase of replicative senescence; however, the number of population doublings and the time

Chiara Mondello; Roberta Riboni; Alessandra Casati; Tiziana Nardo; Fiorella Nuzzo

1997-01-01

101

The Impact of Drug Use on Earnings: A Life-Span Perspective.  

ERIC Educational Resources Information Center

Among a longitudinal cohort of 400 employed males, illicit drug use had a positive impact on wages up to age 28-29 and a negative impact by the mid-30s. A life-span perspective emphasizes differential short- and long-term impacts of education, training, and job changes on users' and nonusers' incomes. Contains 57 references. (Author/SV)

Kandel, Denise; And Others

1995-01-01

102

Perceptions of Personal Agency and Infant Attachment: Toward a Life-Span Perspective on Competence Development.  

ERIC Educational Resources Information Center

Sketches the outlines of a life-span perspective on competence development, which focuses on beliefs about one's potential for producing desirable outcomes. The concern is with the nature and implications of individual differences in perceptions of personal agency and likely origins and development of the perceptions in the early years. (Author/BB)

Ford, Martin E.; Thompson, Ross A.

1985-01-01

103

A Life-Span Analysis of Rural Kansas Children's Mental and Social Development: First Year Report.  

ERIC Educational Resources Information Center

This first year report of a life span analysis of rural Kansas children's mental and social development focuses on the children's cognitive development and the effect of family attitudes and child caring patterns on the children's development. The subjects, 62 rural children aged 3, 6, and 9 years, are to be interviewed annually. Initial analysis…

Poresky, Robert H.; And Others

104

Design & application of MIS on UAV quality & reliability for total life span  

Microsoft Academic Search

From increasing the quality and reliability of military products, the new ensuring quality system for UAVs is established. Firstly, the current quality management for UAVs is analyzed. The focus and limitation of the total life-span quality management is introduced from developing, producing and equipping. Secondly, the quality and reliability information system is introduced on information searching, disposing and using. The

Zhiqiu Chen; Jianjun Luo; Hong Jiang; Weiping Shi

2009-01-01

105

Expression of a Single-Copy hsp-16.2 Reporter Predicts Life span  

PubMed Central

The level of green fluorescent protein expression from an hsp-16.2–based transcriptional reporter predicts life span and thermotolerance in Caenorhabditis elegans. The initial report used a high-copy number reporter integrated into chromosome IV. There was concern that the life-span prediction power of this reporter was not attributable solely to hsp-16.2 output. Specifically, prediction power could stem from disruption of some critical piece of chromatin on chromosome IV by the gpIs1 insertion, a linked mutation from the process used to create the reporter, or from an artifact of transgene regulation (multicopy transgenes are subject to regulation by C elegans chromatin surveillance machinery). Here we determine if the ability to predict life span and thermotolerance is specific to the gpIs1 insertion or a general property of hsp-16.2–based reporters. New single-copy hsp-16.2–based reporters predict life span and thermotolerance. We conclude that prediction power of hsp-16.2–based transcriptional reporters is not an artifact of any specific transgene configuration or chromatin surveillance mechanism.

Tedesco, Patricia M.; Taylor, Larry D.; Lowe, Anita; Cypser, James R.; Johnson, Thomas E.

2012-01-01

106

Cancer risk among atomic bomb survivors. The RERF Life Span Study. Radiation Effects Research Foundation  

Microsoft Academic Search

This article summarizes the risk of cancer among the survivors of the atomic bombing of Hiroshima and Nagasaki. We focus primarily on the risk of death from cancer among individuals in the Life Span Study sample of the Radiation Effects Research Foundation from 1950 through 1985 based on recently revised dosimetry procedures. We report the risk of cancer other than

Y. Shimizu; W. J. Schull; H. Kato

1990-01-01

107

Leaf Life Span Plasticity in Tropical Seedlings Grown under Contrasting Light Regimes  

Microsoft Academic Search

? Background and Aims The phenotypic plasticity of leaf life span in response to low resource conditions has a potentially large impact on the plant carbon budget, notably in evergreen species not subject to seasonal leaf shedding, but has rarely been well documented. This study evaluates the plasticity of leaf longevity, in terms of its quantitative importance to the plant

GREGOIRE VINCENT

2006-01-01

108

Extension of Cell Life-Span and Telomere Length in Animals Cloned from Senescent Somatic Cells  

Microsoft Academic Search

The potential of cloning depends in part on whether the procedure can reverse cellular aging and restore somatic cells to a phenotypically youthful state. Here, we report the birth of six healthy cloned calves derived from populations of senescent donor somatic cells. Nuclear transfer extended the replicative life-span of senescent cells (zero to four population doublings remaining) to greater than

Robert P. Lanza; Jose B. Cibelli; Catherine Blackwell; Vincent J. Cristofalo; Mary Kay Francis; Gabriela M. Baerlocher; Jennifer Mak; Michael Schertzer; Elizabeth A. Chavez; Nancy Sawyer; Peter M. Lansdorp; Michael D. West

2000-01-01

109

D-Glucosamine supplementation extends life span of nematodes and of ageing mice  

PubMed Central

D-Glucosamine (GlcN) is a freely available and commonly used dietary supplement potentially promoting cartilage health in humans, which also acts as an inhibitor of glycolysis. Here we show that GlcN, independent of the hexosamine pathway, extends Caenorhabditis elegans life span by impairing glucose metabolism that activates AMP-activated protein kinase (AMPK/AAK-2) and increases mitochondrial biogenesis. Consistent with the concept of mitohormesis, GlcN promotes increased formation of mitochondrial reactive oxygen species (ROS) culminating in increased expression of the nematodal amino acid-transporter 1 (aat-1) gene. Ameliorating mitochondrial ROS formation or impairment of aat-1-expression abolishes GlcN-mediated life span extension in an NRF2/SKN-1-dependent fashion. Unlike other calorie restriction mimetics, such as 2-deoxyglucose, GlcN extends life span of ageing C57BL/6 mice, which show an induction of mitochondrial biogenesis, lowered blood glucose levels, enhanced expression of several murine amino-acid transporters, as well as increased amino-acid catabolism. Taken together, we provide evidence that GlcN extends life span in evolutionary distinct species by mimicking a low-carbohydrate diet.

Weimer, Sandra; Priebs, Josephine; Kuhlow, Doreen; Groth, Marco; Priebe, Steffen; Mansfeld, Johannes; Merry, Troy L.; Dubuis, Sebastien; Laube, Beate; Pfeiffer, Andreas F.; Schulz, Tim J.; Guthke, Reinhard; Platzer, Matthias; Zamboni, Nicola; Zarse, Kim; Ristow, Michael

2014-01-01

110

Adapting to the Environment across the Life Span: Different Process or Different Inputs?  

ERIC Educational Resources Information Center

Describes a model of adaptation to the environment across the life span. Proposes that an individual's performance in an activity is affected not only by cognitive capacity but also by perceptions and definitions of the activity. Empirical support for the model, based on a survey of individuals' everyday experiences and on laboratory studies, is…

Sansone, Carol; Berg, Cynthia A.

1993-01-01

111

Abilities and Competencies in Adulthood: Life-Span Perspectives on Workplace Skills.  

ERIC Educational Resources Information Center

This report presents a framework for considering general and work-related adult cognitive performance that is drawn from current theory and research on life-span developmental and cognitive psychology. The first section considers the concept of basic skills and the classical distinction between achievement and aptitude. By drawing linkages between…

Smith, Jacqui; Marsiske, Michael

112

Target of rapamycin signaling regulates metabolism, growth, and life span in Arabidopsis.  

PubMed

Target of Rapamycin (TOR) is a major nutrition and energy sensor that regulates growth and life span in yeast and animals. In plants, growth and life span are intertwined not only with nutrient acquisition from the soil and nutrition generation via photosynthesis but also with their unique modes of development and differentiation. How TOR functions in these processes has not yet been determined. To gain further insights, rapamycin-sensitive transgenic Arabidopsis thaliana lines (BP12) expressing yeast FK506 Binding Protein12 were developed. Inhibition of TOR in BP12 plants by rapamycin resulted in slower overall root, leaf, and shoot growth and development leading to poor nutrient uptake and light energy utilization. Experimental limitation of nutrient availability and light energy supply in wild-type Arabidopsis produced phenotypes observed with TOR knockdown plants, indicating a link between TOR signaling and nutrition/light energy status. Genetic and physiological studies together with RNA sequencing and metabolite analysis of TOR-suppressed lines revealed that TOR regulates development and life span in Arabidopsis by restructuring cell growth, carbon and nitrogen metabolism, gene expression, and rRNA and protein synthesis. Gain- and loss-of-function Ribosomal Protein S6 (RPS6) mutants additionally show that TOR function involves RPS6-mediated nutrition and light-dependent growth and life span in Arabidopsis. PMID:23275579

Ren, Maozhi; Venglat, Prakash; Qiu, Shuqing; Feng, Li; Cao, Yongguo; Wang, Edwin; Xiang, Daoquan; Wang, Jinghe; Alexander, Danny; Chalivendra, Subbaiah; Logan, David; Mattoo, Autar; Selvaraj, Gopalan; Datla, Raju

2012-12-01

113

Marital, reproductive, and educational behaviors covary with life expectancy.  

PubMed

Theories of "life history evolution" suggest that individuals might adjust the timing of marriage and reproduction, as well as their propensity to terminate a marriage or pregnancy and invest in skill development, in response to indicators of the locally prevailing level of life expectancy. In particular, such theories generate the hypothesis that foreshortened time horizons lead to hastened reproduction and marriage whereas lengthier time horizons increase the likelihood of reproductive and marital termination and lead to greater investment in education. Here, I show that the scheduling and occurrence of marital and reproductive behavior (including both initiation and termination), as well as levels of educational attainment and investment, covary with life expectancy, even after controlling for the effects of affluence. In analyses of variation in marital, reproductive, and educational behaviors at two jurisdictional levels in Canada, life expectancy was positively correlated with patterns of age-specific fertility, age at first marriage, divorce, abortion, conferral of high school and higher education degrees (with the exception of the trades) and mean number of years of schooling. The large and highly consistent relationships observed between life expectancy and the behaviors under investigation suggest that these associations may be mediated by individual "perceptions" of life expectancy, though more research is needed before conclusions can be firmly reached. PMID:22484517

Krupp, Daniel Brian

2012-12-01

114

Overexpression of Mn superoxide dismutase does not increase life span in mice.  

PubMed

Genetic manipulations of Mn superoxide dismutase (MnSOD), SOD2 expression have demonstrated that altering the level of MnSOD activity is critical for cellular function and life span in invertebrates. In mammals, Sod2 homozygous knockout mice die shortly after birth, and alterations of MnSOD levels are correlated with changes in oxidative damage and in the generation of mitochondrial reactive oxygen species. In this study, we directly tested the effects of overexpressing MnSOD in young (4-6 months) and old (26-28 months) mice on mitochondrial function, levels of oxidative damage or stress, life span, and end-of-life pathology. Our data show that an approximately twofold overexpression of MnSOD throughout life in mice resulted in decreased lipid peroxidation, increased resistance against paraquat-induced oxidative stress, and decreased age-related decline in mitochondrial ATP production. However, this change in MnSOD expression did not alter either life span or age-related pathology. PMID:19633237

Jang, Youngmok C; Pérez, Viviana I; Song, Wook; Lustgarten, Michael S; Salmon, Adam B; Mele, James; Qi, Wenbo; Liu, Yuhong; Liang, Hanyu; Chaudhuri, Asish; Ikeno, Yuji; Epstein, Charles J; Van Remmen, Holly; Richardson, Arlan

2009-11-01

115

D-chiro-inositol and pinitol extend the life span of Drosophila melanogaster.  

PubMed

D-chiro-inositol, a member of the inositol family, and pinitol, a 3-methoxy analogue of D-chiro-inositol, have been proposed to have antidiabetic, antiinflammatory, anticancer and stamina enhancing effects. We found that supplementing the diet of Drosophila with D-chiro-inositol and pinitol extended adult longevity in both male and female flies. Life span extension was accompanied by protection against oxidative and starvation stresses, improvement in health span, and no reduction in fecundity. Pinitol increased the fly life span, both in dietary restriction and in ad libitum conditions, suggesting that pinitol increased life span in a manner that was independent of the dietary restriction pathway. Nuclear localization of dFOXO increased in D-chiro-inositol and pinitol-fed flies when compared with controls. Pinitol treatment significantly activated JNK and S6K, but not AKT, indicating that the activation of dFOXO by pinitol is acquired by the activation of S6K and JNK signaling. Hence, our study indicated that D-chiro-inositol and pinitol could be novel food-derived antiaging compounds. PMID:22843669

Hada, Binika; Yoo, Mi-Ra; Seong, Ki Moon; Jin, Young-Woo; Myeong, Hyeon-Koon; Min, Kyung-Jin

2013-03-01

116

Effect of habitat preference on frond life span in three Cyathea tree ferns  

NASA Astrophysics Data System (ADS)

It has been reported that plants living in various geographical areas had different physiological forms, as factors of microenvironment have strong impacts on physiological characters. However, the physiological characters of fronds have been scarcely reported in ferns. In this study, we investigated physiological differences in response to the habitat preference in the three tree ferns in northeast Taiwan, Cyathea lepifera, C. spinulosa, and C. podophylla, prefer to open site, edge of forest, and interior forest, respectively. The canopy openness above the individuals of C. lepifera, C. spinulosa and C. podophylla were 29.2 ± 14.10 , 7.0 ± 3.07 and 5.0 ± 2.24 %, respectively. Among three species, C. podophylla had the longest frond life span (13.0 ± 4.12 months) than the two others (C. lepifera (6.8 ± 1.29 months) and C. spinulosa (7.3 ±1.35 months). Our result supported the general patterns that shade intolerant species have a shorter leaf life span than shade tolerant species. The maximum net CO2 assimilation of C. lepifera, C. spinulosa and C. podophylla were 11.46 ± 1.34, 8.27 ± 0.69, and 6.34 ± 0.54 ?mol CO2 m-2 s-1, respectively. As well, C. lepifera had the highest photosynthetic light saturation point (LSP), while C. podophylla had the lowest LSP among these three tree ferns. These suggested that C. lepifera could be more efficient for capturing and utilizing light resources under the larger canopy openness condition than the other two species. We also found that frond C : N ratio were positively correlated with frond life span among species. C. podophylla, with the longest frond life span, had the highest frond C : N ratio (22.17 ± 1.95), which was followed by C. spinulosa (18.58 ± 1.37) and C. lepifera (18.68 ± 2.63) with shorter frond life span. The results were consistent to the theory that the fronds and leaves of shade intolerant species have high photosynthetic abilities with low C : N ratio. Key words: Canopy openness, frond life span, tree fern, Cyathea, frond C : N ratio

Chiu, Tzu Yun; Wang, Hsiang Hua; Lun Kuo, Yao; Kume, Tomonori

2013-04-01

117

Reproduction and life history in diatoms  

Microsoft Academic Search

Summary  The Pennales are diplonts and possess sexual, parthenogenetic or apogamous auxospore formation. Fusion is either isogamous\\u000a or physiologically anisogamous.\\u000a \\u000a Sexual reproduction among the Centrales, with the exception ofMelosira, is not fully understood. It is probable, however, that the Centrales are also diplonts. Contradicting claims of various\\u000a authors can be explained through the assumption that the microspores are spermatozoids which fertilize

Lothar Geitler

1935-01-01

118

Demography of Genotypes: Failure of the Limited Life-Span Paradigm in Drosophila melanogaster  

NASA Astrophysics Data System (ADS)

Experimental systems that are amenable to genetic manipulation can be used to address fundamental questions about genetic and nongenetic determinants of longevity. Analysis of large cohorts of ten genotypes of Drosophila melanogaster raised under conditions that favored extended survival has revealed variation between genotypes in both the slope and location of age-specific mortality curves. More detailed examination of a single genotype showed that the mortality trajectory was best fit by a two-stage Gompertz model, with no age-specific increase in mortality rates beyond 30 days after emergence. These results are contrary to the limited life-span paradigm, which postulates well-defined, genotype-specific limits on life-span and brief periods of intense and rapidly accelerating mortality rates at the oldest ages.

Curtsinger, James W.; Fukui, Hidenori H.; Townsend, David R.; Vaupel, James W.

1992-10-01

119

Reproductive and early life stages pathology - Histopathology workshop report  

USGS Publications Warehouse

Pathology occurring during reproduction and larval development represents an important part of the life cycle of fish, and the diseases that affect eggs and larvae often result in significant losses. However, mortality during this period is frequently ignored or poorly researched as the temptation is to replace the losses rather than investigate the causes. A histopathology workshop organised at the newly refurnished laboratory within the Danish Veterinary School was an opportunity to discuss the pathology of selected diseases associated with Reproductive and Early Life Stages Pathology. Several people also kindly provided reference slides.

Bruno, D. W.; Nowak, B.; Elliott, D. G.

2006-01-01

120

Life Satisfaction, Self-Esteem, and Subjective Age in Women across the Life Span  

ERIC Educational Resources Information Center

A study of 320 women, ages 21 to 69, explored the relations among relationship status, subjective age, self-esteem, and life satisfaction. Women in married or partnered relationships had higher levels of life satisfaction than did single women. Women in their 30s and 40s had significantly lower levels of life satisfaction than did other age…

Borzumato-Gainey, Christine; Kennedy, Alison; McCabe, Beth; Degges-White, Suzanne

2009-01-01

121

A Critique of Heckhausen and Schulz's (1995) Life-Span Theory of Control From a Cross-Cultural Perspective  

Microsoft Academic Search

J. Heckhausen and R. Schulz (1995) proposed a life-span theory of control that applies the concepts of primary and secondary control. Although their approach is useful in focusing attention on control across the life span in Western contexts, it breaks down when seen from various Asian and other cultural perspectives. In much of Asia, secondary control takes on primacy and

Stephen J. Gould

1999-01-01

122

Pma1, a P-type proton ATPase, is a determinant of chronological life span in fission yeast.  

PubMed

Chronological life span is defined by how long a cell can survive in a non-dividing state. In yeast, it is measured by viability after entry into stationary phase. To date, some factors affecting chronological life span have been identified; however, the molecular details of how these factors regulate chronological life span have not yet been elucidated clearly. Because life span is a complicated phenomenon and is supposedly regulated by many factors, it is necessary to identify new factors affecting chronological life span to understand life span regulation. To this end, we have screened for long-lived mutants and identified Pma1, an essential P-type proton ATPase, as one of the determinants of chronological life span. We show that partial loss of Pma1 activity not only by mutations but also by treatment with the Pma1 inhibitory chemical vanadate resulted in the long-lived phenotype in Schizosaccharomyces pombe. These findings suggest a novel way to manipulate chronological life span by modulating Pma1 as a molecular target. PMID:20829365

Ito, Hirokazu; Oshiro, Tomoko; Fujita, Yasuyuki; Kubota, Sachiko; Naito, Chikako; Ohtsuka, Hokuto; Murakami, Hiroshi; Aiba, Hirofumi

2010-11-01

123

Mitochondrial Reactive Oxygen Species Trigger Hypoxia-Inducible Factor-Dependent Extension of the Replicative Life Span during Hypoxia  

Microsoft Academic Search

Physiological hypoxia extends the replicative life span of human cells in culture. Here, we report that hypoxic extension of replicative life span is associated with an increase in mitochondrial reactive oxygen species (ROS) in primary human lung fibroblasts. The generation of mitochondrial ROS is necessary for hypoxic activation of the transcription factor hypoxia-inducible factor (HIF). The hypoxic extension of replicative

Eric L. Bell; Tatyana A. Klimova; James Eisenbart; Paul T. Schumacker; Navdeep S. Chandel

2007-01-01

124

Ribosomal proteins Rpl10 and Rps6 are potent regulators of yeast replicative life span  

Microsoft Academic Search

The yeast ribosome is composed of two subunits, the large 60S subunit (LSU) and the small 40S subunit (SSU) and harbors 78 ribosomal proteins (RPs), 59 of which are encoded by duplicate genes. Recently, deletions of the LSU paralogs RPL31A and RPL6B were found to increase significantly yeast replicative life span (RLS). RPs Rpl10 and Rps6 are known translational regulators.

Andreas Chiocchetti; Jia Zhou; Huashun Zhu; Thomas Karl; Olaf Haubenreisser; Mark Rinnerthaler; Gino Heeren; Kamil Oender; Johann Bauer; Helmut Hintner; Michael Breitenbach; Lore Breitenbach-Koller

2007-01-01

125

Nutrition Through the Life Span: Needs and Health Concerns in Critical Periods  

Microsoft Academic Search

\\u000a The focus of this chapter is to discuss the nutritional requirements of individuals in different periods of life, spanning\\u000a from infancy and childhood to old age. We start with the pregnancy and maternal nutritional needs, which ultimately determine\\u000a fetal growth and development. We continue by addressing the main issues in infancy, childhood, and adolescence, focusing on\\u000a the critical nutrients in

Jasminka Z. Ilich; Rhonda A. Brownbill

126

Dependence of the life span of the honeybee ( Apis mellifica ) upon flight performance and energy consumption  

Microsoft Academic Search

The life span of worker-honeybees is determined by the duration of the hive-period and of the foraging period (Figs. 1,2). The duration of the forgaing period is regulated in the following way: Total flight performance of the individual bee seems to be fixed. Daily flight performance strongly affects total flight duration. High daily flight performance decreases maximal flight duration and

Angelika Neukirch

1982-01-01

127

Leaf life span spectrum of tropical woody seedlings: effects of light and ontogeny and consequences for survival  

PubMed Central

Background and Aims Leaf life span is widely recognized as a key life history trait associated with herbivory resistance, but rigorous comparative data are rare for seedlings. The goal of this study was to examine how light environment affects leaf life span, and how ontogenetic development during the first year may influence leaf fracture toughness, lamina density and stem density that are relevant for herbivory resistance, leaf life span and seedling survival. Methods Data from three experiments encompassing 104 neotropical woody species were combined. Leaf life span, lamina and vein fracture toughness, leaf and stem tissue density and seedling survival were quantified for the first-year seedlings at standardized ontogenetic stages in shade houses and common gardens established in gaps and shaded understorey in a moist tropical forest in Panama. Mortality of naturally recruited seedlings till 1 year later was quantified in 800 1-m2 plots from 1994 to 2011. Key Results Median leaf life span ranged widely among species, always greater in shade (ranging from 151 to >1790 d in the understorey and shade houses) than in gaps (115–867 d), but with strong correlation between gaps and shade. Leaf and stem tissue density increased with seedling age, whereas leaf fracture toughness showed only a weak increase. All these traits were positively correlated with leaf life span. Leaf life span and stem density were negatively correlated with seedling mortality in shade, while gap mortality showed no correlation with these traits. Conclusions The wide spectrum of leaf life span and associated functional traits reflects variation in shade tolerance of first-year seedlings among coexisting trees, shrubs and lianas in this neotropical forest. High leaf tissue density is important in enhancing leaf toughness, a known physical defence, and leaf life span. Both seedling leaf life span and stem density should be considered as key functional traits that contribute to seedling survival in tropical forest understoreys.

Kitajima, Kaoru; Cordero, Roberto A.; Wright, S. Joseph

2013-01-01

128

Life span of B lymphocytes: the experimental basis for conflicting results  

SciTech Connect

Recent claims have challenged the view that most peripheral, mature B cells are long-lived, and propose rates of peripheral decay that are compatible with bone marrow production. This disagreement can only reflect differences in the protocols and methods used to measure peripheral lymphocyte life spans. The authors have now assessed toxic or other nonselective effects of hydroxyurea treatment on the survival and migration of peripheral, noncycling cells, as well as possible reasons for exaggerated decays of LPS-reactive B cells transferred to LPS nonresponder hosts, the two methods leading to conclusions of short life spans. They also studied general effects on cell survival introduced by either repeated (/sup 3/H)thymidine injections or the stress associated with surgery, thoracic duct cannulation in particular - methods with which the notion of long life spans had been established. The results failed to show toxic or nonselective effects of hydroxyurea treatments and artificial decays of LPS-reactive cells in adoptive hosts. In contrast, the present experiments demonstrate that both the stress associated with surgery and repeated (/sup 3/H) thymidine administration profoundly deplete a pool of short-lived B cells, consequently selecting for an apparent higher proportion of long-lived cells.

Freitas, A.A.; Rocha, B.; Coutinho, A.A.

1986-02-01

129

Dystrophin-deficient mdx mice display a reduced life span and are susceptible to spontaneous rhabdomyosarcoma.  

PubMed

Duchenne muscular dystrophy (DMD) is the most common, lethal genetic disorder of children. A number of animal models of muscular dystrophy exist, but the most effective model for characterizing the structural and functional properties of dystrophin and therapeutic interventions has been the mdx mouse. Despite the approximately 20 years of investigations of the mdx mouse, the impact of the disease on the life span of mdx mice and the cause of death remain unresolved. Consequently, a life span study of the mdx mouse was designed that included cohorts of male and female mdx and wild-type C57BL/10 mice housed under specific pathogen-free conditions with deaths restricted to natural causes and with examination of the carcasses for pathology. Compared with wild-type mice, both mdx male and female mice had reduced life spans and displayed a progressively dystrophic muscle histopathology. Surprisingly, old mdx mice were prone to develop muscle tumors that resembled the human form of alveolar rhabdomyosarcoma, a cancer associated with poor prognosis. Rhabdomyosarcomas have not been observed previously in nontransgenic mice. The results substantiate the mdx mouse as an important model system for studies of the pathogenesis of and potential remedies for DMD. PMID:17360850

Chamberlain, Jeffrey S; Metzger, Joseph; Reyes, Morayma; Townsend, DeWayne; Faulkner, John A

2007-07-01

130

Effects of dimethylaminoethanol upon life-span and behavior of aged Japanese quail.  

PubMed

The lysosome hypothesis of aging predicts that membrane stabilizers will extend life-span. Stabilizers containing the dimethylaminoethanol moiety (DMAE) have been reported to extend the life-span of drosophila and mice. We tested the prediction in Japanese quail (N = 15) by administering DMAE bitartrate (18.4 mg/kg/day) in the drinking water for 69 weeks, starting at 195 weeks of age. A matched control group (N = 14) received tartaric acid (4.0 mg/kg/day) in the water. Contrary to the prediction, the DMAE-treated group has a shorter life-span after start of treatment (49 weeks) than the controls (69 weeks). No significant differences between the groups were observed in body weight or daily fluid intake. Three behavioral studies were carried out on survivors at 243-249 weeks of age, namely; activity response to light-flash; sexual mounting response to a female quail; and classical conditioning of the heart rate. Aged quail differed from young-adults in changes in motor activity in response to light flashes. Aged quail appeared less responsive initially to reinforced conditioning trials and demonstrated extinction when light flash was not followed by electric shock. There were no detectable differences in latency to mount or in basal heart rate, either as a function of age or as a function of DMAE treatment. PMID:830732

Cherkin, A; Exkardt, M J

1977-01-01

131

Effects of superoxide dismutase/catalase mimetics on life span and oxidative stress resistance in the housefly, Musca domestica.  

PubMed

The purpose of this study was to determine whether superoxide dismutase/catalase mimetics lengthen the life span of the housefly, Musca domestica, as previously demonstrated for the nematode Caenorhabditis elegans. Various concentrations of Eukarion-8 or Eukarion-134 were administered via the drinking water and the effects on the life span of the flies and amounts of protein carbonyls were determined under normoxic and hyperoxic conditions. These SOD/catalase mimetics neither extended the life span of the flies nor attenuated the protein carbonyl content under normoxic conditions and shortened life span under hyperoxic conditions. Thus, the effect of these SOD/catalase mimetics on the life span of animals seem to be species-specific. PMID:12031907

Bayne, Anne-Cécile V; Sohal, Rajindar S

2002-06-01

132

Life span of C57 mice as influenced by radiation dose, dose rate, and age at exposure  

SciTech Connect

This study was designed to measure the life shortening of C57BL/6J male mice as a result of exposure to five external doses from /sup 60/Co gamma radiation delivered at six different dose rates. Total doses ranged from 20 to 1620 rad at exposure rates ranging from 0.7 to 36,000 R/day. The ages of the mice at exposure were newborn, 2, 6, or 15 months. Two replications were completed. Although death was the primary endpoint, we did perform gross necropsies. The life span findings are variable, but we found no consistent shortening compared to control life spans. Therefore, we cannot logically extrapolate life shortening to lower doses, from the data we have obtained. In general, the younger the animals were at the beginning of exposure, the longer their life spans were compared to those of controls. This relationship weakened at the higher doses and dose rates, as mice in these categories tended not to have significantly different life spans from controls. Using life span as a criterion, we find this study suggests that some threshold dosage may exist beyond which effects of external irradiation may be manifested. Up to this threshold, there is no shortening effect on life span compared to that of control mice. Our results are in general agreement with the results of other researchers investigating human and other animal life span effects on irradiation.

Spalding, J.F.; Thomas, R.G.; Tietjen, G.L.

1982-10-01

133

Dead or Alive: Deformed Wing Virus and Varroa destructor Reduce the Life Span of Winter Honeybees  

PubMed Central

Elevated winter losses of managed honeybee colonies are a major concern, but the underlying mechanisms remain controversial. Among the suspects are the parasitic mite Varroa destructor, the microsporidian Nosema ceranae, and associated viruses. Here we hypothesize that pathogens reduce the life expectancy of winter bees, thereby constituting a proximate mechanism for colony losses. A monitoring of colonies was performed over 6 months in Switzerland from summer 2007 to winter 2007/2008. Individual dead workers were collected daily and quantitatively analyzed for deformed wing virus (DWV), acute bee paralysis virus (ABPV), N. ceranae, and expression levels of the vitellogenin gene as a biomarker for honeybee longevity. Workers from colonies that failed to survive winter had a reduced life span beginning in late fall, were more likely to be infected with DWV, and had higher DWV loads. Colony levels of infection with the parasitic mite Varroa destructor and individual infections with DWV were also associated with reduced honeybee life expectancy. In sharp contrast, the level of N. ceranae infection was not correlated with longevity. In addition, vitellogenin gene expression was significantly positively correlated with ABPV and N. ceranae loads. The findings strongly suggest that V. destructor and DWV (but neither N. ceranae nor ABPV) reduce the life span of winter bees, thereby constituting a parsimonious possible mechanism for honeybee colony losses.

Evans, Jay D.; Chen, Yan Ping; Gauthier, Laurent; Neumann, Peter

2012-01-01

134

Meaning and Purpose in Life across the Life Span: A Cross-Sectional Multivariate Analysis.  

ERIC Educational Resources Information Center

This paper explores the developmental changes in meaning and purpose across the life course. Thirty males and females at the developmental stages of young adulthood (16-29 years), early middle-age (30-49 years), late middle-age (50-64 years), young-old (65-74 years) and old-old (75+ years) completed the Reker and Peacock (1981) Life Attitude…

Reker, Gary T.; And Others

135

Life history and the competitive environment: trajectories of growth, maturation, and reproductive output among chacma baboons.  

PubMed

The social environment is a key feature influencing primate life histories. Chacma baboons (Papio hamadryas ursinus) are a female-bonded species with a strict linear dominance hierarchy. In this species, the allocation of energy to competing demands of growth and reproduction is hypothesized to vary as a function of competitive ability, which in turn increases with social rank. Since growth rate is a major component of life history models, measures of age-specific growth were used to analyze variation in life history traits across social ranks. Weights of 42 immature baboons were obtained without sedation or baiting from a troop of well-habituated chacma baboons in the Okavango Delta, Botswana. Using demographic and weight data from this wild population, five main findings emerged: 1) Weight for age and growth rate of infant and juvenile females are positively associated with maternal rank. 2) Male growth is not influenced by maternal rank. 3) Female growth shows smaller variation across feeding conditions than male growth. 4) Low-ranking adult females continue investment in offspring through prolonged lactation until they reach a weight comparable to that of high-ranking infants. 5) The benefit of rank to reproductive success shown in this study is 0.83 additional offspring. Reproductive span determined predominantly by age at maturation contributes 27-38% to the difference in expected number of offspring by rank, vs. 62-73% due to reproductive rate. These findings have major implications for understanding the role of social environment in phenotypic plasticity of life history traits, and in the evolution of primate life histories. PMID:12489139

Johnson, Sara E

2003-01-01

136

Comparative transcriptional pathway bioinformatic analysis of dietary restriction, Sir2, p53 and resveratrol life span extension in Drosophila  

PubMed Central

A multiple comparison approach using whole genome transcriptional arrays was used to identify genes and pathways involved in calorie restriction/dietary restriction (DR) life span extension in Drosophila. Starting with a gene centric analysis comparing the changes in common between DR and two DR related molecular genetic life span extending manipulations, Sir2 and p53, lead to a molecular confirmation of Sir2 and p53's similarity with DR and the identification of a small set of commonly regulated genes. One of the identified upregulated genes, takeout, known to be involved in feeding and starvation behavior, and to have sequence homology with Juvenile Hormone (JH) binding protein, was shown to directly extend life span when specifically overexpressed. Here we show that a pathway centric approach can be used to identify shared physiological pathways between DR and Sir2, p53 and resveratrol life span extending interventions. The set of physiological pathways in common among these life span extending interventions provides an initial step toward defining molecular genetic and physiological changes important in life span extension. The large overlap in shared pathways between DR, Sir2, p53 and resveratrol provide strong molecular evidence supporting the genetic studies linking these specific life span extending interventions.

Antosh, Michael; Whitaker, Rachel; Kroll, Adam; Hosier, Suzanne; Chang, Chengyi; Bauer, Johannes; Cooper, Leon

2011-01-01

137

Comparative transcriptional pathway bioinformatic analysis of dietary restriction, Sir2, p53 and resveratrol life span extension in Drosophila.  

PubMed

A multiple comparison approach using whole genome transcriptional arrays was used to identify genes and pathways involved in calorie restriction/dietary restriction (DR) life span extension in Drosophila. Starting with a gene centric analysis comparing the changes in common between DR and two DR related molecular genetic life span extending manipulations, Sir2 and p53, lead to a molecular confirmation of Sir2 and p53's similarity with DR and the identification of a small set of commonly regulated genes. One of the identified upregulated genes, takeout, known to be involved in feeding and starvation behavior, and to have sequence homology with Juvenile Hormone (JH) binding protein, was shown to directly extend life span when specifically overexpressed. Here we show that a pathway centric approach can be used to identify shared physiological pathways between DR and Sir2, p53 and resveratrol life span extending interventions. The set of physiological pathways in common among these life span extending interventions provides an initial step toward defining molecular genetic and physiological changes important in life span extension. The large overlap in shared pathways between DR, Sir2, p53 and resveratrol provide strong molecular evidence supporting the genetic studies linking these specific life span extending interventions. PMID:21325893

Antosh, Michael; Whitaker, Rachel; Kroll, Adam; Hosier, Suzanne; Chang, Chengyi; Bauer, Johannes; Cooper, Leon; Neretti, Nicola; Helfand, Stephen L

2011-03-15

138

Drosophila foxo acts in males to cause sexual-dimorphism in tissue-specific p53 life span effects  

PubMed Central

Sex-specific selective pressures are hypothesized to lead to sexually antagonistic gene functions that contribute to phenotypes such as aging and cancer. However, relatively little is known about the identity of such genes and possible mechanisms. Here we report that nervous system-specific over-expression of wild-type p53 in Drosophila caused decreased life span in males and increased life span in females. In contrast, tissue-general over-expression produced the opposite pattern: increased life span in males and decreased life span in females. In a foxo null background, p53 life span effects in males were reversed, becoming similar to the effects in females. In contrast, a Sir2 null background tended to reduce the magnitude of p53 effects. The data demonstrate that wild-type p53 over-expression can regulate life span independent of foxo, and suggest that foxo acts in males to produce sexually antagonistic life span effects of p53.

Shen, Jie; Tower, John

2009-01-01

139

Estrogen-related mood disorders: reproductive life cycle factors.  

PubMed

Women are at higher risk throughout their reproductive lives than are men for major depression. Numerous molecular and clinical studies have implicated estrogen in modulating brain function including that related to mood. In an attempt to present a conceptual model, the literature of the past 30 years on mood and well-being throughout reproductive life is reviewed as it relates to activity of endogenous, bio-identical, and synthetic estrogen in women. Results indicate that sudden estrogen withdrawal, fluctuating estrogen, and sustained estrogen deficit are correlated with significant mood disturbance. Clinical recovery from depression postpartum, perimenopause, and postmenopause through restoration of stable/optimal levels of estrogen has been noted. PMID:16292022

Douma, S L; Husband, C; O'Donnell, M E; Barwin, B N; Woodend, A K

2005-01-01

140

From Children to Adults: Motor Performance across the Life-Span  

PubMed Central

The life-span approach to development provides a theoretical framework to examine the general principles of life-long development. This study aims to investigate motor performance across the life span. It also aims to investigate if the correlations between motor tasks increase with aging. A cross-sectional design was used to describe the effects of aging on motor performance across age groups representing individuals from childhood to young adult to old age. Five different motor tasks were used to study changes in motor performance within 338 participants (7–79 yrs). Results showed that motor performance increases from childhood (7–9) to young adulthood (19–25) and decreases from young adulthood (19–25) to old age (66–80). These results are mirroring results from cognitive research. Correlation increased with increasing age between two fine motor tasks and two gross motor tasks. We suggest that the findings might be explained, in part, by the structural changes that have been reported to occur in the developing and aging brain and that the theory of Neural Darwinism can be used as a framework to explain why these changes occur.

Leversen, Jonas S. R.; Haga, Monika; Sigmundsson, Hermundur

2012-01-01

141

From children to adults: motor performance across the life-span.  

PubMed

The life-span approach to development provides a theoretical framework to examine the general principles of life-long development. This study aims to investigate motor performance across the life span. It also aims to investigate if the correlations between motor tasks increase with aging. A cross-sectional design was used to describe the effects of aging on motor performance across age groups representing individuals from childhood to young adult to old age. Five different motor tasks were used to study changes in motor performance within 338 participants (7-79 yrs). Results showed that motor performance increases from childhood (7-9) to young adulthood (19-25) and decreases from young adulthood (19-25) to old age (66-80). These results are mirroring results from cognitive research. Correlation increased with increasing age between two fine motor tasks and two gross motor tasks. We suggest that the findings might be explained, in part, by the structural changes that have been reported to occur in the developing and aging brain and that the theory of Neural Darwinism can be used as a framework to explain why these changes occur. PMID:22719958

Leversen, Jonas S R; Haga, Monika; Sigmundsson, Hermundur

2012-01-01

142

Photosynthetic thermotolerance of woody savanna species in China is correlated with leaf life span  

PubMed Central

Background and Aims Photosynthetic thermotolerance (PT) is important for plant survival in tropical and sub-tropical savannas. However, little is known about thermotolerance of tropical and sub-tropical wild plants and its association with leaf phenology and persistence. Longer-lived leaves of savanna plants may experience a higher risk of heat stress. Foliar Ca is related to cell integrity of leaves under stresses. In this study it is hypothesized that (1) species with leaf flushing in the hot-dry season have greater PT than those with leaf flushing in the rainy season; and (2) PT correlates positively with leaf life span, leaf mass per unit area (LMA) and foliar Ca concentration ([Ca]) across woody savanna species. Methods The temperature-dependent increase in minimum fluorescence was measured to assess PT, together with leaf dynamics, LMA and [Ca] for a total of 24 woody species differing in leaf flushing time in a valley-type savanna in south-west China. Key Results The PT of the woody savanna species with leaf flushing in the hot-dry season was greater than that of those with leaf flushing in the rainy season. Thermotolerance was positively associated with leaf life span and [Ca] for all species irrespective of the time of flushing. The associations of PT with leaf life span and [Ca] were evolutionarily correlated. Thermotolerance was, however, independent of LMA. Conclusions Chinese savanna woody species are adapted to hot-dry habitats. However, the current maximum leaf temperature during extreme heat stress (44·3 °C) is close to the critical temperature of photosystem II (45·2 °C); future global warming may increase the risk of heat damage to the photosynthetic apparatus of Chinese savanna species.

Zhang, Jiao-Lin; Poorter, L.; Hao, Guang-You; Cao, Kun-Fang

2012-01-01

143

Caffeine extends life span, improves healthspan, and delays age-associated pathology in Caenorhabditis elegans  

PubMed Central

Background The longevity of an organism is influenced by both genetic and environmental factors. With respect to genetic factors, a significant effort is being made to identify pharmacological agents that extend life span by targeting pathways with a defined role in the aging process. On the environmental side, the molecular mechanisms responsible for the positive influence of interventions such as dietary restriction are being explored. The environment experienced by humans in modern societies already contains countless compounds that may influence longevity. Understanding the role played by common compounds that substantially affect the aging process will be critical for predicting and interpreting the outcome of introducing new interventions. Caffeine is the most widely used psychoactive drug worldwide. Prior studies in flies, worms, and mice indicate that caffeine may positively impact age-associated neurodegenerative pathology, such as that observed in Alzheimer’s disease. Results Here we report that caffeine is capable of extending life span and improving healthspan in Caenorhabditis elegans, a finding that is in agreement with a recently published screen looking for FDA-approved compounds capable of extending worm life span. Life span extension using caffeine displays epistatic interaction with two known longevity interventions: dietary restriction and reduced insulin signaling. Caffeine treatment also delays pathology in a nematode model of polyglutamine disease. Conclusions The identification of caffeine as a relevant factor in aging and healthspan in worms, combined with prior work in both humans and rodents linking caffeine consumption to reduced risk of age-associated disease, suggests that caffeine may target conserved longevity pathways. Further, it may be important to consider caffeine consumption when developing clinical interventions, particularly those designed to mimic dietary restriction or modulate insulin/IGF-1-like signaling. The positive impact of caffeine on a worm model of polyglutamine disease suggests that chronic caffeine consumption may generally enhance resistance to proteotoxic stress and may be relevant to assessing risk and developing treatments for human diseases like Alzheimer’s and Huntington’s disease. Future work addressing the relevant targets of caffeine in models of aging and healthspan will help to clarify the underlying mechanisms and potentially identify new molecular targets for disease intervention.

2012-01-01

144

Life-history theory, fertility and reproductive success in humans.  

PubMed Central

According to life-history theory, any organism that maximizes fitness will face a trade-off between female fertility and offspring survivorship. This trade-off has been demonstrated in a variety of species, but explicit tests in humans have found a positive linear relationship between fitness and fertility. The failure to demonstrate a maximum beyond which additional births cease to enhance fitness is potentially at odds with the view that human fertility behaviour is currently adaptive. Here we report, to our knowledge, the first clear evidence for the predicted nonlinear relationship between female fertility and reproductive success in a human population, the Dogon of Mali, West Africa. The predicted maximum reproductive success of 4.1+/-0.3 surviving offspring was attained at a fertility of 10.5 births. Eighty-three per cent of the women achieved a lifetime fertility level (7-13 births) for which the predicted mean reproductive success was within the confidence limits (3.4 to 4.8) for reproductive success at the optimal fertility level. Child mortality, rather than fertility, was the primary determinant of fitness. Since the Dogon people are farmers, our results do not support the assumptions that: (i) contemporary foragers behave more adaptively than agriculturalists, and (ii) that adaptive fertility behaviour ceased with the Neolithic revolution some 9000 years ago. We also present a new method that avoids common biases in measures of reproductive success.

Strassmann, Beverly I; Gillespie, Brenda

2002-01-01

145

Candidate genes affecting Drosophila life span identified by integrating microarray gene expression analysis and QTL mapping.  

PubMed

The current increase in life expectancy observed in industrialized societies underscores the need to achieve a better understanding of the aging process that could help the development of effective strategies to achieve healthy aging. This will require not only identifying genes involved in the aging process, but also understanding how their effects are modulated by environmental factors, such as dietary intake and life style. Although the human genome has been sequenced, it may be impractical to study humans or other long-lived organisms to gain a mechanistic understanding about the aging process. Thus, short-lived animal models are essential to identifying the mechanisms and genes that affect the rate and quality of aging as a first step towards identifying genetic variants in humans. In this study, we investigated gene expression changes between two strains of Drosophila (Oregon and 2b) for which quantitative trait loci (QTLs) affecting life span were identified previously. We collected males and females from both strains at young and old ages, and assessed whole genome variation in transcript abundance using Affymetrix GeneChips. We observed 8217 probe sets with detectable transcripts. A total of 2371 probe sets, representing 2220 genes, exhibited significant changes in transcript abundance with age; and 839 probe sets were differentially expressed between Oregon and 2b. We focused on the 359 probe sets (representing 354 genes) that exhibited significant changes in gene expression both with age and between strains. We used these genes to integrate the analysis of microarray gene expression data, bioinformatics, and the results of genetic mapping studies reported previously, to identify 49 candidate genes and four pathways that could potentially be responsible for regulating life span and involved in the process of aging in Drosophila and humans. PMID:17196240

Lai, Chao-Qiang; Parnell, Laurence D; Lyman, Richard F; Ordovas, Jose M; Mackay, Trudy F C

2007-03-01

146

Genetic Deletion of Nrf2 Promotes Immortalization and Decreases Life Span of Murine Embryonic Fibroblasts  

PubMed Central

Nuclear factor E2–related factor-2 (Nrf2) transcription factor is one of the main regulators of intracellular redox balance and a sensor of oxidative and electrophilic stress. Low Nrf2 activity is usually associated with carcinogenesis, but Nrf2 is also considered as an oncogene because it increases survival of transformed cells. Because intracellular redox balance alterations are involved in both senescence and tumorigenesis, we investigated the impact of Nrf2 genetic deletion on cellular immortalization and life span of murine embryonic fibroblasts. We report that Nrf2 genetic deletion promotes immortalization due to an early loss of p53-dependent gene expression. However, compared with control cells, immortalized Nrf2?/? murine embryonic fibroblasts exhibited decreased growth, lower cyclin E levels, and impaired expression of NQO1 and cytochrome b5 reductase. Moreover, SirT1 was also significantly reduced in immortalized Nrf2?/? murine embryonic fibroblasts, and these cells exhibited shorter life span. Our results underscore the dual role of Nrf2 in protection against carcinogenesis and in the delay of cellular aging.

Jodar, Laura; Mercken, Evi M.; Ariza, Julia; Younts, Caitlin; Gonzalez-Reyes, Jose A.; Alcain, Francisco J.; Buron, Isabel; de Cabo, Rafael

2011-01-01

147

Rapamycin extends life span of Rb1+/? mice by inhibiting neuroendocrine tumors  

PubMed Central

Chronic treatment of mice with an enterically released formulation of rapamycin (eRapa) extends median and maximum life span, partly by attenuating cancer. The mechanistic basis of this response is not known. To gain a better understanding of these in vivo effects, we used a defined preclinical model of neuroendocrine cancer, Rb1+/? mice. Previous results showed that diet restriction (DR) had minimal or no effect on the lifespan of Rb1+/? mice, suggesting that the beneficial response to DR is dependent on pRb1. Since long-term eRapa treatment may at least partially mimic chronic DR in lifespan extension, we predicted that it would have a minimal effect in Rb1+/? mice. Beginning at 9 weeks of age until death, we fed Rb1+/? mice a diet without or with eRapa at 14 mg/kg food, which results in an approximate dose of 2.24 mg/kg body weight per day, and yielded rapamycin blood levels of about 4 ng/ml. Surprisingly, we found that eRapa dramatically extended life span of both female and male Rb1+/? mice, and slowed the appearance and growth of pituitary and decreased the incidence of thyroid tumors commonly observed in these mice. In this model, eRapa appears to act differently than DR, suggesting diverse mechanisms of action on survival and anti-tumor effects. In particular the beneficial effects of rapamycin did not depend on the dose of Rb1.

Livi, Carolina B.; Hardman, Rulon L.; Christy, Barbara A.; Dodds, Sherry G.; Jones, Diane; Williams, Charnae; Strong, Randy; Bokov, Alex; Javors, Martin A.; Ikeno, Yuji; Hubbard, Gene; Hasty, Paul; Sharp, Zelton Dave

2013-01-01

148

Yeast endosulfines control entry into quiescence and chronological life span by inhibiting protein phosphatase 2A.  

PubMed

The TORC1 and PKA protein kinases are central elements of signaling networks that regulate eukaryotic cell proliferation in response to growth factors and/or nutrients. In yeast, attenuation of signaling by these kinases following nitrogen and/or carbon limitation activates the protein kinase Rim15, which orchestrates the initiation of a reversible cellular quiescence program to ensure normal chronological life span. The molecular elements linking Rim15 to distal readouts including the expression of Msn2/4- and Gis1-dependent genes involve the endosulfines Igo1/2. Here, we show that Rim15, analogous to the greatwall kinase in Xenopus, phosphorylates endosulfines to directly inhibit the Cdc55-protein phosphatase 2A (PP2A(Cdc55)). Inhibition of PP2A(Cdc55) preserves Gis1 in a phosphorylated state and consequently promotes its recruitment to and activation of transcription from promoters of specific nutrient-regulated genes. These results close a gap in our perception of and delineate a role for PP2A(Cdc55) in TORC1-/PKA-mediated regulation of quiescence and chronological life span. PMID:23273919

Bontron, Séverine; Jaquenoud, Malika; Vaga, Stefania; Talarek, Nicolas; Bodenmiller, Bernd; Aebersold, Ruedi; De Virgilio, Claudio

2013-01-31

149

Caenorhabditis elegans RNA-processing Protein TDP-1 Regulates Protein Homeostasis and Life Span*?  

PubMed Central

Transactive response DNA-binding protein (TARDBP/TDP-43), a heterogeneous nuclear ribonucleoprotein (hnRNP) with diverse activities, is a common denominator in several neurodegenerative disorders, including amyotrophic lateral sclerosis and frontotemporal lobar degeneration. Orthologs of TDP-43 exist in animals ranging from mammals to invertebrates. Here, we systematically studied mutant Caenorhabditis elegans lacking the nematode TDP-43 ortholog, TDP-1. Heterologous expression of human TDP-43 rescued the defects in C. elegans lacking TDP-1, suggesting their functions are conserved. Although the tdp-1 mutants exhibited deficits in fertility, growth, and locomotion, loss of tdp-1 attenuated defects in several C. elegans models of proteotoxicity. Loss of tdp-1 suppressed defects in transgenic C. elegans expressing TDP-43 or CuZn superoxide dismutase, both of which are associated with proteotoxicity in neurodegenerative diseases. Loss of tdp-1 also reduced defects in mutant animals lacking the heat shock factor HSF-1. Transcriptional profiling demonstrated that the loss of TDP-1 altered expression of genes functioning in RNA processing and protein folding. Furthermore, the absence of tdp-1 extended the life span in C. elegans. The life span extension required a FOXO transcriptional factor DAF-16 but not HSF-1. These results suggest that the C. elegans TDP-1 has a role in the regulation of protein homeostasis and aging.

Zhang, Tao; Hwang, Ho-Yon; Hao, Haiping; Talbot, Conover; Wang, Jiou

2012-01-01

150

Life-Span Exposure to Low Doses of Aspartame Beginning during Prenatal Life Increases Cancer Effects in Rats  

PubMed Central

Background In a previous study conducted at the Cesare Maltoni Cancer Research Center of the European Ramazzini Foundation (CMCRC/ERF), we demonstrated for the first time that aspartame (APM) is a multipotent carcinogenic agent when various doses are administered with feed to Sprague-Dawley rats from 8 weeks of age throughout the life span. Objective The aim of this second study is to better quantify the carcinogenic risk of APM, beginning treatment during fetal life. Methods We studied groups of 70–95 male and female Sprague-Dawley rats administered APM (2,000, 400, or 0 ppm) with feed from the 12th day of fetal life until natural death. Results Our results show a) a significant dose-related increase of malignant tumor–bearing animals in males (p < 0.01), particularly in the group treated with 2,000 ppm APM (p < 0.01); b) a significant increase in incidence of lymphomas/leukemias in males treated with 2,000 ppm (p < 0.05) and a significant dose-related increase in incidence of lymphomas/leukemias in females (p < 0.01), particularly in the 2,000-ppm group (p < 0.01); and c) a significant dose-related increase in incidence of mammary cancer in females (p < 0.05), particularly in the 2,000-ppm group (p < 0.05). Conclusions The results of this carcinogenicity bioassay confirm and reinforce the first experimental demonstration of APM’s multipotential carcinogenicity at a dose level close to the acceptable daily intake for humans. Furthermore, the study demonstrates that when life-span exposure to APM begins during fetal life, its carcinogenic effects are increased.

Soffritti, Morando; Belpoggi, Fiorella; Tibaldi, Eva; Esposti, Davide Degli; Lauriola, Michelina

2007-01-01

151

Spermatozoid life-span of two brown seaweeds, Saccharina japonica and Undaria pinnatifida, as measured by fertilization efficiency  

NASA Astrophysics Data System (ADS)

During sexual reproduction of seaweeds, spermatozoid (sperm) discharge is triggered by chemical messengers (pheromones) released by the female gametes. The chemotactic ability of the sperm ensures fertilization success. Using unialgal male and female gametophyte material under designated standard gametogenesis testing (SGT) conditions, the potential life-span of the sperm of two seaweeds, Saccharina japonica and Undaria pinnatifida, was assessed by their ability to fertilize eggs. Results show that within 20-30 min after being discharged, sperm of both species could complete fertilization without an apparent decline in fertilization rate. Although fertilization rate 60-120 min after sperm discharge dropped significantly in both species, some sperm were viable enough to fertilize the eggs. In S. japonica, at 12°C, some sperm were able to fertilize eggs up to 12 h after discharge. In both species, egg discharge rates (EDR) in the male and female mixed positive controls were significantly higher than those of all the sperm-testing groups. Doubling the seeded male gametophytes of S. japonica in the SGT tests significantly increased the EDR, further confirming the effect of the presence of the male on the female in terms of facilitating egg discharge from oogonia.

Li, Jing; Pang, Shaojun; Liu, Feng; Shan, Tifeng; Gao, Suqin

2013-07-01

152

Distinct Biological Epochs in the Reproductive Life of Female Drosophila melanogaster  

PubMed Central

Mating alters the physiology and behavior of female Drosophila melanogaster resulting in a surge of egg laying, a decrease in receptivity to other males, and a decrease in life span. Here, we show striking differences in patterns of Drosophila egg laying and mortality rate dependent upon mating history. Our data reveal previously unreported epochs in the reproductive life of females: optimal, vulnerable and declining-terminal. During the optimal period, mating induces females to respond with a surge in egg laying and has a reversible effect on mortality rate. In contrast, during the vulnerable period, mating does not induce females to respond with a surge in egg laying and causes an irreversible increase in mortality rate. The terminal period was always observed several days before death, irrespective of the chronological age, and is marked by sharp reductions in egg laying. The presence of these distinctive biological epochs may reflect increased female sensitivity to mating due to age-related decline.

Rogina, Blanka; Wolverton, Tom; Bross, Tyson G.; Chen, Kun; Muller, Hans-Georg; Carey, James R.

2008-01-01

153

Biological impact of auditory expertise across the life span: musicians as a model of auditory learning.  

PubMed

Experience-dependent characteristics of auditory function, especially with regard to speech-evoked auditory neurophysiology, have garnered increasing attention in recent years. This interest stems from both pragmatic and theoretical concerns as it bears implications for the prevention and remediation of language-based learning impairment in addition to providing insight into mechanisms engendering experience-dependent changes in human sensory function. Musicians provide an attractive model for studying the experience-dependency of auditory processing in humans due to their distinctive neural enhancements compared to nonmusicians. We have only recently begun to address whether these enhancements are observable early in life, during the initial years of music training when the auditory system is under rapid development, as well as later in life, after the onset of the aging process. Here we review neural enhancements in musically trained individuals across the life span in the context of cellular mechanisms that underlie learning, identified in animal models. Musicians' subcortical physiologic enhancements are interpreted according to a cognitive framework for auditory learning, providing a model in which to study mechanisms of experience-dependent changes in human auditory function. PMID:23988583

Strait, Dana L; Kraus, Nina

2014-02-01

154

Lower bounds for the life-span of solutions of nonlinear wave equations in three dimensions  

PubMed Central

The paper deals with strict solutions u(x,t) = u(x1,x2,x3,t) of an equation [Formula: see text] where Du is the set of four first derivatives of u. For given initial values u(x,0) = ?F(x), ut(x,0) = ?G(x), the life span T(?) is defined as the supremum of all t to which the local solution can be extended for all x. Blowup in finite time corresponds to T(?) < ?. Examples show that this can occur for arbitrarily small ?. On the other hand, T(?) must at least be very large for small ?. By assuming that aik,F,G [unk] C?, that aik(0) = 0, and that F,G have compact support, it is shown that [Formula: see text] for every N. This result had been established previously only for N < 4.

John, Fritz

1982-01-01

155

Invited commentary: missing doses in the life span study of Japanese atomic bomb survivors.  

PubMed

The Life Span Study is a long-term epidemiologic cohort study of survivors of the atomic bombs dropped on Hiroshima and Nagasaki, Japan. In this issue of the Journal, Richardson et al. (Am J Epidemiol. 2013;177(6):562-568) suggest that those who died in the earliest years of follow-up were more likely to have a missing dose of radiation exposure assigned, leading to a bias in the radiation risk estimates. We show that nearly all members of the cohort had shielding information recorded before the beginning of follow-up and that much of the alleged bias that Richardson et al. describe simply reflects the geographic distribution of shielding conditions for which reliable dosimetry was impossible. PMID:23429724

Ozasa, K; Grant, E J; Cullings, H M; Shore, R E

2013-03-15

156

Males shorten the life span of C. elegans hermaphrodites via secreted compounds.  

PubMed

How an individual's longevity is affected by the opposite sex is still largely unclear. In the nematode Caenorhabditis elegans, the presence of males accelerated aging and shortened the life span of individuals of the opposite sex (hermaphrodites), including long-lived or sterile hermaphrodites. The male-induced demise could occur without mating and required only exposure of hermaphrodites to medium in which males were once present. Such communication through pheromones or other diffusible substances points to a nonindividual autonomous mode of aging regulation. The male-induced demise also occurred in other species of nematodes, suggesting an evolutionary conserved process whereby males may induce the disposal of the opposite sex to save resources for the next generation or to prevent competition from other males. PMID:24292626

Maures, Travis J; Booth, Lauren N; Benayoun, Bérénice A; Izrayelit, Yevgeniy; Schroeder, Frank C; Brunet, Anne

2014-01-31

157

Extension of cell life-span and telomere length in animals cloned from senescent somatic cells.  

PubMed

The potential of cloning depends in part on whether the procedure can reverse cellular aging and restore somatic cells to a phenotypically youthful state. Here, we report the birth of six healthy cloned calves derived from populations of senescent donor somatic cells. Nuclear transfer extended the replicative life-span of senescent cells (zero to four population doublings remaining) to greater than 90 population doublings. Early population doubling level complementary DNA-1 (EPC-1, an age-dependent gene) expression in cells from the cloned animals was 3.5- to 5-fold higher than that in cells from age-matched (5 to 10 months old) controls. Southern blot and flow cytometric analyses indicated that the telomeres were also extended beyond those of newborn (<2 weeks old) and age-matched control animals. The ability to regenerate animals and cells may have important implications for medicine and the study of mammalian aging. PMID:10784448

Lanza, R P; Cibelli, J B; Blackwell, C; Cristofalo, V J; Francis, M K; Baerlocher, G M; Mak, J; Schertzer, M; Chavez, E A; Sawyer, N; Lansdorp, P M; West, M D

2000-04-28

158

Virtual navigation strategies from childhood to senescence: evidence for changes across the life span.  

PubMed

This study sought to investigate navigational strategies across the life span, by testing 8-years old children to 80-years old healthy older adults on the 4 on 8 virtual maze (4/8VM). The 4/8VM was previously developed to assess spontaneous navigational strategies, i.e., hippocampal-dependent spatial strategies (navigation by memorizing relationships between landmarks) versus caudate nucleus-dependent response strategies (memorizing a series of left and right turns from a given starting position). With the 4/8VM, we previously demonstrated greater fMRI activity and gray matter in the hippocampus of spatial learners relative to response learners. A sample of 599 healthy participants was tested in the current study. Results showed that 84.4% of children, 46.3% of young adults, and 39.3% of older adults spontaneously used spatial strategies (p < 0.0001). Our results suggest that while children predominantly use spatial strategies, the proportion of participants using spatial strategies decreases across the life span, in favor of response strategies. Factors promoting response strategies include repetition, reward and stress. Since response strategies can result from successful repetition of a behavioral pattern, we propose that the increase in response strategies is a biological adaptive mechanism that allows for the automatization of behavior such as walking in order to free up hippocampal-dependent resources. However, the down-side of this shift from spatial to response strategies occurs if people stop building novel relationships, which occurs with repetition and routine, and thereby stop stimulating their hippocampus. Reduced fMRI activity and gray matter in the hippocampus were shown to correlate with cognitive deficits in normal aging. Therefore, these results have important implications regarding factors involved in healthy and successful aging. PMID:23162463

Bohbot, Veronique D; McKenzie, Sam; Konishi, Kyoko; Fouquet, Celine; Kurdi, Vanessa; Schachar, Russel; Boivin, Michel; Robaey, Philippe

2012-01-01

159

Niacin-bound chromium increases life span in Zucker Fatty Rats.  

PubMed

Avoiding insulin resistance (IR) associated with aging might lengthen life span based on previous studies using caloric-restricted animals. We assessed whether consuming niacin-bound chromium (NBC) alone or in a formula containing other so-called "insulin sensitizers" would overcome various manifestations of aging and extend life span in Zucker Fatty Rats (ZFR). We compared many metabolic parameters of ZFR fed NBC alone (n=12) or NBC in a unique formula (n=10) to a control group (n=10). In addition to NBC, the formula contained Allium sativum, Momordica charantia, Trigonella foenum-graecum and Gymnema sylvestre. The formula group received roughly 1/2 as much NBC daily as the NBC group. At week 44, all rats still lived, and no abnormalities in blood count (CBC), renal, or liver functions were found. In the two treatment groups compared to control, circulating glucose levels were significantly lower, with a trend toward lower HbA1C. Relatively elevated cholesterol and triglyceride concentrations occurred in the formula group. Compared to control, the NBC group had increased average lifespan (21.8%), median lifespan (14.1%), 30th percentile survival (19.6%), and maximum lifespan (22%). Despite similar beneficial effects on the glucose and blood pressure systems, a difference in aging was also found when the NBC group was compared to the formula group. When all rats in the other two groups had died, four in the NBC group continued to live at least a month longer. We attribute lack of a similar aging effect in the formula group to either lower dosing of NBC and/or that various ingredients in the formula counteracted the antiaging effect(s) of NBC. PMID:21930012

Preuss, Harry G; Echard, Bobby; Clouatre, Dallas; Bagchi, Debasis; Perricone, Nicholas V

2011-10-01

160

Role of cellular mechanics in the function and life span of vascular endothelium.  

PubMed

The vascular endothelium plays a crucial role in vessel homeostasis and is implicated in the pathogenesis of cardiovascular disease. The function and life span of endothelial cells, therefore, have a large impact upon the quality and expectancy of an individual's life. Exposure to haemodynamic forces determines the phenotype of endothelial cells. Turbulent blood flow, disturbed shear stress and a rising tension of the vessel wall result in endothelial dysfunction and an enhanced endothelial cell turnover. In this scenario, the role of endothelial mechanics is yet poorly described. The streaming blood exerts shear forces transmitted to the soft cortical actin mesh immediately underneath the plasma membrane. The mechanical properties of this actin cortex seem to be an important regulator of endothelial function. Aldosterone and high plasma sodium stiffen the endothelial cell cortex which is accompanied by a decrease in NO release. If endothelial stiffening is only transient, it may be a useful mechanism to compensate for any decrease in arterial blood pressure. Long-term stiffening of the cell, however, may lead to endothelial dysfunction and may contribute to cardiovascular disorders, as observed in disturbed aldosterone/sodium homeostasis. In this case, the mineralocorticoid receptor antagonist spironolactone maintains the endothelial cell cortex soft and thereby preserves normal endothelial function and longevity. This may explain the recently observed beneficial effects of spironolactone on the cardiovascular system. Taken together, the review highlights the importance of elasticity for normal endothelial function. PMID:21318292

Kliche, Katrin; Jeggle, Pia; Pavenstädt, Hermann; Oberleithner, Hans

2011-08-01

161

Aging Theories for Establishing Safe Life Spans of Airborne Critical Structural Components  

NASA Technical Reports Server (NTRS)

New aging theories have been developed to establish the safe life span of airborne critical structural components such as B-52B aircraft pylon hooks for carrying air-launch drop-test vehicles. The new aging theories use the equivalent-constant-amplitude loading spectrum to represent the actual random loading spectrum with the same damaging effect. The crack growth due to random loading cycling of the first flight is calculated using the half-cycle theory, and then extrapolated to all the crack growths of the subsequent flights. The predictions of the new aging theories (finite difference aging theory and closed-form aging theory) are compared with the classical flight-test life theory and the previously developed Ko first- and Ko second-order aging theories. The new aging theories predict the number of safe flights as considerably lower than that predicted by the classical aging theory, and slightly lower than those predicted by the Ko first- and Ko second-order aging theories due to the inclusion of all the higher order terms.

Ko, William L.

2003-01-01

162

Radiation effects on cancer risks in the Life Span Study cohort.  

PubMed

To determine late health effects of radiation in atomic bomb survivors, the Radiation Effects Research Foundation has been conducting studies on the Life Span Study (LSS) population, which consists of 93,000 atomic bomb survivors and 27,000 controls. A recent report on the incidence of solid cancers estimates that at the age of 70 y, after exposure at the age of 30 y, solid-cancer rates increase by about 35% per Gy for men and 58% per Gy for women. The age-at-exposure is an important risk modifier. Furthermore, it seems that radiation-associated increases in cancer rates persist throughout life. In addition, radiation has similar effects upon first-primary and second-primary cancer risks. A recent report on leukemia mortality suggested that the effect of radiation on leukemia mortality persisted for more than five decades. In addition, a significant dose-response for myelodysplastic syndrome is found in Nagasaki LSS members 40-60 y after radiation exposure. In view of the nature of the continuing increase in solid cancers, the LSS should continue to provide important new information on cancer risks, as most survivors still alive today were exposed to the atomic bomb radiation under the age of 20 y and are now entering their cancer-prone years. PMID:22908358

Kodama, Kazunori; Ozasa, Kotaro; Katayama, Hiroaki; Shore, Roy E; Okubo, Toshiteru

2012-10-01

163

The relationship of cancer mortality to life span and food supply rate  

SciTech Connect

Survival curves for men and women dying from cardiovascular disease and similar curves for those dying from cancer in 47 countries were compared with the 1970-1974 per capita incomes of the inhabitants. The data were taken chiefly from 1964 life tables. The steepest survival curves were found in countries with the highest incomes. Comparison of the survival curves in different countries and comparison of cardiovascular survival with cancer survival curves indicate that both groups of diseases are probably diseases of senescence. The differences in survival slopes are interpreted as homeostatic responses in the population to rate of food intake. The response protects the population against long-term effects of changes in food supply by promoting differential reproduction of offspring best suited to the food supply rate fro the environment. The response to food supply rate complicates calculation of the effects of protracted exposure to low-level ionizing radiation because the radiation exposure appears to mimic the effec of extra food.

Totter, J.R.; Adler, H.I.; Storer, J.B.

1985-08-01

164

Effects of temperature on the life span, vitality and fine structure of Drosophila melanogaster.  

PubMed

The effects of temperature on the aging process have been investigated in approximately 3500 imagoes of male Drosophila melanogaster (Oregon R), with focus on the following parameters: mortality, O2 utilization, vitality (as expressed by negative geotaxis and mating) and fine structural alterations in the abdominal organs and brain. The data on mortality kinetics of flies maintained continuously at 18 degrees, 21 degrees, 27 degrees or 30 degrees C or exposed in succession to 21 degrees and 27 degrees C or vice versa support the concept that life span is temperature dependent. Moreover, these data, together with the increased O2 utilization and accelerated loss of vitality at 21 degrees C as compared with 18 degrees C, suggest that, in agreement with the rate-of-living theory proposed by Alpatov and Pearl in 1929, the flies are living faster at the higher temperature. Fine structural aging changes, like ribosomal loss in the Malpighian tubules and lipofuscin-ceroid accumulation in the midgut cells, seem to be more intense at 27 degrees and at 29 degrees C than at 21 degrees C. Also, the low vitality exhibited through their lives by flies kept at previous exposure through many generations) to 21 degrees C. Flies maintained at 29 degrees C showed a striking degeneration of the brain with an almost complete loss of the cytoplasmic organelles of the nerve cells. This electron microscopic finding lends support to the view that nervous tissue injury (perhaps induced by thermal denaturation of membrane lipoproteins) may play a crucial role in life shortening induced by relatively high temperatures. PMID:823384

Miquel, J; Lundgren, P R; Bensch, K G; Atlan, H

1976-01-01

165

Caenorhabditis elegans ATR checkpoint kinase ATL-1 influences life span through mitochondrial maintenance.  

PubMed

ATR is highly conserved in all eukaryotes and functions as a cell-cycle nuclear checkpoint kinase. In mammals, ATR is essential whose complete absence results in early embryonic lethality and its hypomorphic mutation causes a complex disease known as Seckel syndrome. However, molecular mechanisms that cause a wide variety of symptoms including accelerated aging have remained unclear. Similarly, in the nematode Caenorhabditis elegans, a deletion mutant of ATR ortholog atl-1 appears to develop into normal adults, but their eggs do not hatch and die at early embryogenesis. Here we show that the parental worms of atl-1 defective mutant achieved longevity. Transcription levels of certain superoxide dismutase genes, sod-3 and -5 and enzymatic activity of superoxide dismutases significantly increased in the mutant. Furthermore, lipid peroxidation such as a formation of malondialdehyde was attenuated. Expressions of other genes regulated by DAF-16/FOXO transcription factor were also altered. In contrast, the mutant became hypersensitive to rotenone and ethidium bromide. Compared with the wild type the mitochondrial DNA copy number in the mutant was lesser and its proliferation is more severely inhibited in the presence of rotenone. These results suggest that C. elegans ATL-1 is involved not only in the nuclear checkpoint control but also in the mitochondrial maintenance, and its dysfunction activates mild oxidative stress response, resulting in an alteration of life span. PMID:23434802

Suetomi, Kazuhiro; Mereiter, Stefan; Mori, Chihiro; Takanami, Takako; Higashitani, Atsushi

2013-11-01

166

Ammonia, respiration, and longevity in nematodes: insights on metabolic regulation of life span from temporal rescaling.  

PubMed

To better understand metabolic correlates of longevity, we used a graphical technique to compare the adult temporal patterns of several markers of metabolic activity - ammonia elimination, oxygen consumption rate, ATP levels, and (in freeze-permeabilized worms) the rate of NADPH-activated, lucigenin-mediated superoxide formation - as observed by us and others in normal and long-lived mutant Caenorhabditis elegans strains. All of these traits declined with time, and when their logarithms were plotted against time, appeared reasonably linear for most of the duration of the experiments. The profiles for ammonia output conformed well to parallel regression lines; those for the other metabolic parameters varied widely in slope as originally plotted by the authors, but much less so when replotted as logarithms against adjusted time, scaled by the reciprocal of strain longevity. This is consistent with coregulation of life span, respiration rate, ATP levels, lucigenin reactivity, but not ammonia excretion, by a physiological clock distinguishable from chronologic time. Plots, scaled appropriately for equalized slopes, highlighted y-axis intercept differences among strains. On rescaled plots, these constitute deviations from the expectation based on 'strain-specific clock' differences alone. With one exception, y-intercept effects were observed only for mutants in an insulin-like signaling pathway. PMID:23604841

Thaden, J J; Shmookler Reis, R J

2000-04-01

167

Atrx deficiency induces telomere dysfunction, endocrine defects, and reduced life span  

PubMed Central

Human ATRX mutations are associated with cognitive deficits, developmental abnormalities, and cancer. We show that the Atrx-null embryonic mouse brain accumulates replicative damage at telomeres and pericentromeric heterochromatin, which is exacerbated by loss of p53 and linked to ATM activation. ATRX-deficient neuroprogenitors exhibited higher incidence of telomere fusions and increased sensitivity to replication stress–inducing drugs. Treatment of Atrx-null neuroprogenitors with the G-quadruplex (G4) ligand telomestatin increased DNA damage, indicating that ATRX likely aids in the replication of telomeric G4-DNA structures. Unexpectedly, mutant mice displayed reduced growth, shortened life span, lordokyphosis, cataracts, heart enlargement, and hypoglycemia, as well as reduction of mineral bone density, trabecular bone content, and subcutaneous fat. We show that a subset of these defects can be attributed to loss of ATRX in the embryonic anterior pituitary that resulted in low circulating levels of thyroxine and IGF-1. Our findings suggest that loss of ATRX increases DNA damage locally in the forebrain and anterior pituitary and causes tissue attrition and other systemic defects similar to those seen in aging.

Watson, L. Ashley; Solomon, Lauren A.; Li, Jennifer Ruizhe; Jiang, Yan; Edwards, Matthew; Shin-ya, Kazuo; Beier, Frank; Berube, Nathalie G.

2013-01-01

168

The frequency of 4 common gene polymorphisms in nonagenarians, centenarians, and average life span individuals.  

PubMed

Single nucleotide polymorphisms of angiotensin-converting enzyme (ACE) such as rs1799752, nuclear factor kappa B (NFkB) such as rs28362491 and cholesteryl ester transport protein (CETP) such as rs708272 (TaqB1) and rs5882 (I405V) were evaluated in nonagenarians, centenarians, and average life span individuals (controls). The study population (n = 307; 190 nonagenarians, 12 centenarians and 105 middle-aged controls) was genotyped for ACE, NFkB, and CETP genetic variants. The age of nonagenarian and centenarian group ranged between 90 and 111 years; centenarians and controls age ranged from 99 to 111, and from 18 to 80 years, respectively. The I carriers of ACE I/D gene were fewer in nonagenarians compared to centenarians (37.6% vs 62.5%, P = .016). The I carriers of ACE gene were more frequent in centenarians compared to controls (62% vs 41%, P = .045). No differences in frequency of common NFkB and CETP genotypes between patients with exceptional longevity and middle-aged patients were observed. PMID:23389097

Kolovou, Genovefa; Kolovou, Vana; Vasiliadis, Ioannis; Giannakopoulou, Vasiliki; Mihas, Constantinos; Bilianou, Helen; Kollia, Aikaterini; Papadopoulou, Evaggelia; Marvaki, Apostolia; Goumas, Georgos; Kalogeropoulos, Petros; Limperi, Sotiria; Katsiki, Niki; Mavrogeni, Sophie

2014-03-01

169

ERYTHROCYTE LIFE SPAN IN GROWING SWINE AS DETERMINED BY GLYCINE-2-C14  

PubMed Central

Red blood cell survival studies were performed on five normal growing swine by following the C14-specific activity of hemoglobin and heme after the administration of glycine-2-C14. The erythrocytes of normal growing swine appear to be destroyed both by a random and an age-dependent process. Random destruction accounts for the larger portion of the cells which are destroyed. The "mean" red cell survival time was 62 days. This represents the interval from the time of incorporation of 50 per cent of the maximal amount of labelling achieved to the time when the level had decreased once more to the 50 per cent amount. The " ‘corrected’ average potential life span" of the red cells was 86 ± 11.5 days. This figure was obtained by subtracting the number of days required to attain 80 per cent of the maximal labelling from the average survival time of red cells destroyed by an age-dependent process as distinguished from random destruction.

Bush, J. A.; Berlin, N. I.; Jensen, W. N.; Brill, A. B.; Cartwright, G. E.; Wintrobe, M. M.

1955-01-01

170

Bone marrow transplantation prolongs life span and ameliorates neurologic manifestations in Sandhoff disease mice.  

PubMed

The GM2 gangliosidoses are a group of severe, neurodegenerative conditions that include Tay-Sachs disease, Sandhoff disease, and the GM2 activator deficiency. Bone marrow transplantation (BMT) was examined as a potential treatment for these disorders using a Sandhoff disease mouse model. BMT extended the life span of these mice from approximately 4.5 mo to up to 8 mo and slowed their neurologic deterioration. BMT also corrected biochemical deficiencies in somatic tissues as indicated by decreased excretion of urinary oligosaccharides, and lower glycolipid storage and increased levels of beta-hexosaminidase activity in visceral organs. Even with neurologic improvement, neither clear reduction of brain glycolipid storage nor improvement in neuronal pathology could be detected, suggesting a complex pathogenic mechanism. Histological analysis revealed beta-hexosaminidase-positive cells in the central nervous system and visceral organs with a concomitant reduction of colloidal iron-positive macrophages. These results may be important for the design of treatment approaches for the GM2 gangliosidoses. PMID:9576752

Norflus, F; Tifft, C J; McDonald, M P; Goldstein, G; Crawley, J N; Hoffmann, A; Sandhoff, K; Suzuki, K; Proia, R L

1998-05-01

171

Dietary Intake of Curcuma longa and Emblica officinalis Increases Life Span in Drosophila melanogaster.  

PubMed

Intake of food and nutrition plays a major role in affecting aging process and longevity. However, the precise mechanisms underlying the ageing process are still unclear. To this respect, diet has been considered to be a determinant of ageing process. In order to better illustrate this, we used Drosophila melanogaster as a model and fed them orally with different concentrations of two commonly used Indian medicinal plant products, Curcuma longa (rhizome) and Emblica officinalis (fruit). The results revealed significant increase in life span of Drosophila flies on exposure to both the plant products, more efficiently by C. Longa than by E. officinalis. In order to understand whether the increase in lifespan was due to high-antioxidant properties of these medicinal plants, we performed enzymatic assays to assess the SOD and catalase activities in case of both treated and control Drosophila flies. Interestingly, the results support the free radical theory of aging as both these plant derivatives show high reactive oxygen species (ROS) scavenging activities. PMID:24967413

Rawal, Shilpa; Singh, Pavneet; Gupta, Ayush; Mohanty, Sujata

2014-01-01

172

Cognitive control and language across the life span: does labeling improve reactive control?  

PubMed

How does cognitive control change with age, and what are the processes underlying these changes? This question has been extensively studied using versions of the task-switching paradigm, which allow participants to actively prepare for the upcoming task (Kray, Eber, & Karbach, 2008). Little is known, however, about age-related changes in this ability across the life span when there is no opportunity to anticipate task goals. We examined the effect of 2 kinds of verbal self-instruction-labeling either the task goal or the relevant feature of the stimulus-on 2 components of cognitive control, goal setting and switching, in children, young adults, and older adults. All participants performed single-task blocks and mixed-task blocks (involving unpredictable switching between 2 tasks) in silent and labeling conditions. Participants categorized bidimensional stimuli either by picture or by color, depending on their spatial position in a 2-cell vertical grid. Response times revealed an inverted U shape in performance with age. These age differences were more pronounced for goal setting than for switching, thus generalizing results obtained in situations taping proactive control to this new context forcing reactive control. Further, differential age-related effects of verbalization were also obtained. Verbalizations were detrimental for young adults, beneficial for older adults, and had mixed effects in children. These differences are interpreted in terms of qualitative developmental changes in reactive goal-setting strategies. PMID:24491213

Lucenet, Joanna; Blaye, Agnès; Chevalier, Nicolas; Kray, Jutta

2014-05-01

173

Dietary Intake of Curcuma longa and Emblica officinalis Increases Life Span in Drosophila melanogaster  

PubMed Central

Intake of food and nutrition plays a major role in affecting aging process and longevity. However, the precise mechanisms underlying the ageing process are still unclear. To this respect, diet has been considered to be a determinant of ageing process. In order to better illustrate this, we used Drosophila melanogaster as a model and fed them orally with different concentrations of two commonly used Indian medicinal plant products, Curcuma longa (rhizome) and Emblica officinalis (fruit). The results revealed significant increase in life span of Drosophila flies on exposure to both the plant products, more efficiently by C. Longa than by E. officinalis. In order to understand whether the increase in lifespan was due to high-antioxidant properties of these medicinal plants, we performed enzymatic assays to assess the SOD and catalase activities in case of both treated and control Drosophila flies. Interestingly, the results support the free radical theory of aging as both these plant derivatives show high reactive oxygen species (ROS) scavenging activities.

Rawal, Shilpa; Singh, Pavneet; Gupta, Ayush; Mohanty, Sujata

2014-01-01

174

Bone marrow transplantation prolongs life span and ameliorates neurologic manifestations in Sandhoff disease mice.  

PubMed Central

The GM2 gangliosidoses are a group of severe, neurodegenerative conditions that include Tay-Sachs disease, Sandhoff disease, and the GM2 activator deficiency. Bone marrow transplantation (BMT) was examined as a potential treatment for these disorders using a Sandhoff disease mouse model. BMT extended the life span of these mice from approximately 4.5 mo to up to 8 mo and slowed their neurologic deterioration. BMT also corrected biochemical deficiencies in somatic tissues as indicated by decreased excretion of urinary oligosaccharides, and lower glycolipid storage and increased levels of beta-hexosaminidase activity in visceral organs. Even with neurologic improvement, neither clear reduction of brain glycolipid storage nor improvement in neuronal pathology could be detected, suggesting a complex pathogenic mechanism. Histological analysis revealed beta-hexosaminidase-positive cells in the central nervous system and visceral organs with a concomitant reduction of colloidal iron-positive macrophages. These results may be important for the design of treatment approaches for the GM2 gangliosidoses.

Norflus, F; Tifft, C J; McDonald, M P; Goldstein, G; Crawley, J N; Hoffmann, A; Sandhoff, K; Suzuki, K; Proia, R L

1998-01-01

175

HIV1 dynamics in vivo: Virion clearance rate, infected cell life-span, and viral generation time  

Microsoft Academic Search

A new mathematical model was used to analyze a detailed set of human immunodeficiency virus-type 1 (HIV-1) viral load data collected from five infected individuals after the administration of a potent inhibitor of HIV-1 protease. Productively infected cells were estimated to have, on average, a life-span of 2.2 days (half-life tââ = 1.6 days), and plasma virions were estimated to

A. S. Perelson; A. U. Neumann; M. Markowitz; D. D. Ho; J. M. Leonard

1996-01-01

176

Tor1/Sch9-Regulated Carbon Source Substitution Is as Effective as Calorie Restriction in Life Span Extension  

PubMed Central

The effect of calorie restriction (CR) on life span extension, demonstrated in organisms ranging from yeast to mice, may involve the down-regulation of pathways, including Tor, Akt, and Ras. Here, we present data suggesting that yeast Tor1 and Sch9 (a homolog of the mammalian kinases Akt and S6K) is a central component of a network that controls a common set of genes implicated in a metabolic switch from the TCA cycle and respiration to glycolysis and glycerol biosynthesis. During chronological survival, mutants lacking SCH9 depleted extracellular ethanol and reduced stored lipids, but synthesized and released glycerol. Deletion of the glycerol biosynthesis genes GPD1, GPD2, or RHR2, among the most up-regulated in long-lived sch9?, tor1?, and ras2? mutants, was sufficient to reverse chronological life span extension in sch9? mutants, suggesting that glycerol production, in addition to the regulation of stress resistance systems, optimizes life span extension. Glycerol, unlike glucose or ethanol, did not adversely affect the life span extension induced by calorie restriction or starvation, suggesting that carbon source substitution may represent an alternative to calorie restriction as a strategy to delay aging.

Madia, Federica; Hu, Jia; Ge, Huanying; Li, Lei M.; Longo, Valter D.

2009-01-01

177

A Life-Span, Relational, Public Health Model of Self-Regulation: Impact on Individual and Community Health  

ERIC Educational Resources Information Center

In this chapter, the authors extend the ideas around the development of self-regulation and its impact on development by proposing a life-span, relational, public health model. They propose that the role of self-regulation should be understood across transitions from childhood to adulthood and through an individual and community perspective,…

Maniar, Swapnil; Zaff, Jonathan F.

2011-01-01

178

Age and calorie-independent life span extension from dietary restriction by bacterial deprivation in Caenorhabditis elegans  

Microsoft Academic Search

BACKGROUND: Dietary restriction (DR) increases life span and delays age-associated disease in many organisms. The mechanism by which DR enhances longevity is not well understood. RESULTS: Using bacterial food deprivation as a means of DR in C. elegans, we show that transient DR confers long-term benefits including stress resistance and increased longevity. Consistent with studies in the fruit fly and

Erica D Smith; Tammi L Kaeberlein; Brynn T Lydum; Jennifer Sager; K Linnea Welton; Brian K Kennedy; Matt Kaeberlein

2008-01-01

179

Living the Dream? A Qualitative Retrospective Study Exploring the Role of Adolescent Aspirations across the Life Span  

ERIC Educational Resources Information Center

There is a lack of longitudinal research linking adolescent career aspirations to adult outcomes other than career and income attainment. Drawing on Nurmi's (2004) and Salmela-Aro, Aunola, and Nurmi's (2007) life-span model of motivation and using quantitative survey data at ages 16, 23, 33, 42, and 50 years, combined with retrospective interview…

Ashby, Julie S.; Schoon, Ingrid

2012-01-01

180

Presence of the intermediate filaments cytokeratins and vimentin in the rat corpus luteum during luteal life-span  

Microsoft Academic Search

The presence of the intermediate filament (IF) proteins cytokeratins and vimentin in corpus luteum (CL) and other parts of the ovary from adult pseudopregnant rats was investigated using immunohistochemistry and immunoblot analysis. To induce pseudopregnancy, female rats were mated with sterile male rats. The mating procedure induces a prolonged luteal life-span of 13±1 days. Positive staining for cytokeratin could be

I. Nilsson; M.-O. Mattsson; G. Selstam

1995-01-01

181

The relationship of sexual daydreaming to sexual activity, sexual drive, and sexual attitudes for women across the life-span  

Microsoft Academic Search

The association among sexual daydreaming and sexual attitudes and activity was examined in a cross-sectional life-span sample of women (N = 117, 26 to 78 years). Sexual daydreaming was measured using the Imaginal Processes Inventory (IPI) while sexual history measures of sexual activity, sexual drive, and sexual attitudes were derived from a comprehensive personal interview. A factor analysis and varimax

Frances E. Purifoy; Alicia Grodsky; Leonard M. Giambra

1992-01-01

182

JNK/FOXO-mediated neuronal expression of fly homologue of peroxiredoxin II reduces oxidative stress and extends life span.  

PubMed

Activation of c-Jun N-terminal kinase (JNK) signaling in neurons increases stress resistance and extends life span, in part through FOXO-mediated transcription in Drosophila. However, the JNK/FOXO target genes are unknown. Here, we identified Jafrac1, a Drosophila homolog of human Peroxiredoxin II (hPrxII), as a downstream effecter of JNK/FOXO signaling in neurons that enhances stress resistance and extends life span. We found that Jafrac1 was expressed in the adult brain and induced by paraquat, a reactive oxygen species-generating chemical. RNA interference-mediated neuronal knockdown of Jafrac1 enhanced, while neuronal overexpression of Jafrac1 and hPrxII suppressed, paraquat-induced lethality in flies. Neuronal expression of Jafrac1 also significantly reduced ROS levels, restored mitochondrial function, and attenuated JNK activation caused by paraquat. Activation of JNK/FOXO signaling in neurons increased the Jafrac1 expression level under both normal and oxidative stressed conditions. Moreover, neuronal knockdown of Jafrac1 shortened, while overexpression of Jafrac1 and hPrxII extended, the life span in flies. These results support the hypothesis that JNK/FOXO signaling extends life span via amelioration of oxidative damage and mitochondrial dysfunction in neurons. PMID:19720829

Lee, Kyu-Sun; Iijima-Ando, Kanae; Iijima, Koichi; Lee, Won-Jae; Lee, Joon H; Yu, Kweon; Lee, Dong-Seok

2009-10-23

183

Generation and Characterization of Telomerase-Transfected Human Lymphatic Endothelial Cells with an Extended Life Span  

PubMed Central

The study of lymphatic endothelial cells and lymphangiogenesis has, in the past, been hampered by the lack of lymphatic endothelial-specific markers. The recent discovery of several such markers has permitted the isolation of lymphatic endothelial cells (LECs) from human skin. However, cell numbers are limited and purity is variable with the different isolation procedures. To overcome these problems, we have transfected human dermal microvascular endothelial cells (HDMVECs) with a retrovirus containing the coding region of human telomerase reverse transcriptase (hTERT), and have produced a cell line, hTERT-HDLEC, with an extended lifespan. hTERT-HDLEC exhibit a typical cobblestone morphology when grown in culture, are contact-inhibited, and express endothelial cell-specific markers. hTERT-HDLEC also express the recognized lymphatic markers, Prox-1, LYVE-1 and podoplanin, as well as integrin ?9, but do not express CD34. They also form tube-like structures in three-dimensional collagen gels when stimulated with vascular endothelial growth factors -A and -C. Based on these currently recognized criteria, these cells are LEC. Surprisingly, we also found that the widely studied HMEC-1 cell line expresses recognized lymphatic markers; however, these cells are also CD34-positive. In summary, the ectopic expression of hTERT increases the life span of LECs and does not affect their capacity to form tube-like structures in a collagen matrix. The production and characterization of hTERT-HDLEC will facilitate the study of the properties of lymphatic endothelium in vitro.

Nisato, Riccardo E.; Harrison, Jillian A.; Buser, Raphaele; Orci, Lelio; Rinsch, Chris; Montesano, Roberto; Dupraz, Philippe; Pepper, Michael S.

2004-01-01

184

Missing doses in the life span study of Japanese atomic bomb survivors.  

PubMed

The Life Span Study of atomic bomb survivors is an important source of risk estimates used to inform radiation protection and compensation. Interviews with survivors in the 1950s and 1960s provided information needed to estimate radiation doses for survivors proximal to ground zero. Because of a lack of interview or the complexity of shielding, doses are missing for 7,058 of the 68,119 proximal survivors. Recent analyses excluded people with missing doses, and despite the protracted collection of interview information necessary to estimate some survivors' doses, defined start of follow-up as October 1, 1950, for everyone. We describe the prevalence of missing doses and its association with mortality, distance from hypocenter, city, age, and sex. Missing doses were more common among Nagasaki residents than among Hiroshima residents (prevalence ratio = 2.05; 95% confidence interval: 1.96, 2.14), among people who were closer to ground zero than among those who were far from it, among people who were younger at enrollment than among those who were older, and among males than among females (prevalence ratio = 1.22; 95% confidence interval: 1.17, 1.28). Missing dose was associated with all-cancer and leukemia mortality, particularly during the first years of follow-up (all-cancer rate ratio = 2.16, 95% confidence interval: 1.51, 3.08; and leukemia rate ratio = 4.28, 95% confidence interval: 1.72, 10.67). Accounting for missing dose and late entry should reduce bias in estimated dose-mortality associations. PMID:23429722

Richardson, David B; Wing, Steve; Cole, Stephen R

2013-03-15

185

Missing Doses in the Life Span Study of Japanese Atomic Bomb Survivors  

PubMed Central

The Life Span Study of atomic bomb survivors is an important source of risk estimates used to inform radiation protection and compensation. Interviews with survivors in the 1950s and 1960s provided information needed to estimate radiation doses for survivors proximal to ground zero. Because of a lack of interview or the complexity of shielding, doses are missing for 7,058 of the 68,119 proximal survivors. Recent analyses excluded people with missing doses, and despite the protracted collection of interview information necessary to estimate some survivors' doses, defined start of follow-up as October 1, 1950, for everyone. We describe the prevalence of missing doses and its association with mortality, distance from hypocenter, city, age, and sex. Missing doses were more common among Nagasaki residents than among Hiroshima residents (prevalence ratio = 2.05; 95% confidence interval: 1.96, 2.14), among people who were closer to ground zero than among those who were far from it, among people who were younger at enrollment than among those who were older, and among males than among females (prevalence ratio = 1.22; 95% confidence interval: 1.17, 1.28). Missing dose was associated with all-cancer and leukemia mortality, particularly during the first years of follow-up (all-cancer rate ratio = 2.16, 95% confidence interval: 1.51, 3.08; and leukemia rate ratio = 4.28, 95% confidence interval: 1.72, 10.67). Accounting for missing dose and late entry should reduce bias in estimated dose-mortality associations.

Richardson, David B.; Wing, Steve; Cole, Stephen R.

2013-01-01

186

Life spanning murine gene expression profiles in relation to chronological and pathological aging in multiple organs.  

PubMed

Aging and age-related pathology is a result of a still incompletely understood intricate web of molecular and cellular processes. We present a C57BL/6J female mice in vivo aging study of five organs (liver, kidney, spleen, lung, and brain), in which we compare genome-wide gene expression profiles during chronological aging with pathological changes throughout the entire murine life span (13, 26, 52, 78, 104, and 130 weeks). Relating gene expression changes to chronological aging revealed many differentially expressed genes (DEGs), and altered gene sets (AGSs) were found in most organs, indicative of intraorgan generic aging processes. However, only ? 1% of these DEGs are found in all organs. For each organ, at least one of 18 tested pathological parameters showed a good age-predictive value, albeit with much inter- and intraindividual (organ) variation. Relating gene expression changes to pathology-related aging revealed correlated genes and gene sets, which made it possible to characterize the difference between biological and chronological aging. In liver, kidney, and brain, a limited number of overlapping pathology-related AGSs were found. Immune responses appeared to be common, yet the changes were specific in most organs. Furthermore, changes were observed in energy homeostasis, reactive oxygen species, cell cycle, cell motility, and DNA damage. Comparison of chronological and pathology-related AGSs revealed substantial overlap and interesting differences. For example, the presence of immune processes in liver pathology-related AGSs that were not detected in chronological aging. The many cellular processes that are only found employing aging-related pathology could provide important new insights into the progress of aging. PMID:23795901

Jonker, Martijs J; Melis, Joost P M; Kuiper, Raoul V; van der Hoeven, Tessa V; Wackers, Paul F K; Robinson, Joke; van der Horst, Gijsbertus T J; Dollé, Martijn E T; Vijg, Jan; Breit, Timo M; Hoeijmakers, Jan H J; van Steeg, Harry

2013-10-01

187

Life span and tissue distribution of 111indium-labeled blood platelets in hypomagnesemic lambs  

SciTech Connect

Circulating platelets may be activated by exposed triple-helical collagen in atherosclerotic lesions in Mg-deficient ruminants. Autologous platelets, labeled in vitro with 111In and determined to be active, were injected into 5 hypomagnesemic and 3 control lambs fed semipurified diets with 100 or 2,000 mg of Mg/kg of feed for 3 months. During the first 68 hours, 111In concentrations were 11 times higher in packed cells than in plasma. Packed-cell 111In increased 60% during the first 2 hours, probably due to initial tissue sequestration and later release of labeled platelets. Thereafter, platelet half-life span averaged 60 and 63 hours for hypomagnesemic and control lambs. After 68 hours, lambs were injected with native vascular collagen fibrils at 500 micrograms/kg of body weight to initiate reversible platelet aggregation. Within 1 minute, 83% of packed-cell 111In disappeared from circulation. Thirty minutes later, the lambs were euthanatized and necropsied and in the lungs, liver, and spleen, 111In averaged 24%, 19%, and 9%, respectively, of 111In injected 68 hours earlier. Organ deposits were not affected by Mg intake, but 111In in the lungs was somewhat lower in 2 lambs injected with inactivated collagen. Pathologic changes induced by reversible platelet aggregation were compatible with right ventricular failure complicated by pulmonary edema, similar to changes in hypomagnesemic lambs that died spontaneously. Platelets in blood exposed to vascular lesions in hypomagnesemic ruminants could be a major mortality risk factor in grass tetany disease.

Schneider, M.D.; Miller, J.K.; White, P.K.; Ramsey, N.

1983-05-01

188

The ontogeny of the human connectome: development and dynamic changes of brain connectivity across the life span.  

PubMed

The human brain comprises distributed cortical regions that are structurally and functionally connected into a network that is known as the human connectome. Elaborate developmental processes starting in utero herald connectome genesis, with dynamic changes in its architecture continuing throughout life. Connectome changes during development, maturation, and aging may be governed by a set of biological rules or algorithms, forming and shaping the macroscopic architecture of the brain's wiring network. To explore the presence of developmental patterns indicative of such rules, this review considers insights from studies on the cellular and the systems level into macroscopic connectome genesis and dynamics across the life span. We observe that in parallel with synaptogenesis, macroscopic connectome formation and transformation is characterized by an initial overgrowth and subsequent elimination of cortico-cortical axonal projections. Furthermore, dynamic changes in connectome organization throughout the life span are suggested to follow an inverted U-shaped pattern, with an increasingly integrated topology during development, a plateau lasting for the majority of adulthood and an increasingly localized topology in late life. Elucidating developmental patterns in brain connectivity is crucial for our understanding of the human connectome and how it may give rise to brain function, including the occurrence of brain network disorders across the life span. PMID:24047610

Collin, Guusje; van den Heuvel, Martijn P

2013-12-01

189

Calorie restriction, post-reproductive life span, and programmed aging: a plea for rigor.  

PubMed

All scientists are acutely aware of the profound challenge that they face when communicating scientific findings to nonscientists, especially when great uncertainty is involved and when the topic is of personal interest to the general public. Simplification of the issues--sometimes extending to a degree of oversimplification--is a sad but generally recognized necessity. It is not, however, a necessity when scientists communicate with each other, and when that happens, the explanation may lie elsewhere: either in the speaker's vested interests or in overconfidence on the speaker's part in the extent to which he or she has grasped the topic under discussion. Both these explanations are serious allegations and must not be made without good reason, not least because an alternative explanation is often the entirely legitimate preference for scientific "shorthand." However, when a general tendency toward oversimplification emerges within an expert community, not only in informal interactions but in learned publications, the field in question can suffer a loss of reputation for rigor, which may especially infect younger scientists joining that field (or contemplating joining it). I feel that this has occurred to a dangerous degree within biogerontology in respect of the way in which the effect of the environment on the rate of aging-whether that of an individual organism or of a lineage-is described. There are still important controversies in that area, but I refer here strictly to issues concerning which a thorough consensus exists. In this essay I highlight some fundamental tenets of biogerontology that are frequently, and to my mind problematically, mis-stated by many in this field in their printed pronouncements. Greater precision on these points will, I believe, benefit biogerontology at many levels, avoiding confusion among biogerontologists, among other biologists, and among the general public. PMID:17717100

De Grey, Aubrey D N J

2007-11-01

190

Crime over the Life Span; Trajectories of Criminal Behavior in Dutch Offenders  

Microsoft Academic Search

How does crime develop over the life course? And how do age, life circumstances, and prior offending affect this development? This thesis seeks to answer these two questions that are central to present day developmental and life course criminology. The research presented is based on the Criminal Career and Life course Study (CCLS), a longitudinal study covering the criminal careers

Arjan Blokland

2005-01-01

191

The pleiotropic effect of the GTS1 gene product on heat tolerance, sporulation and the life span of Saccharomyces cerevisiae.  

PubMed

We investigated whether or not the potential clock gene, GTS1, of the yeast Saccharomyces cerevisiae, shows pleiotropic effects on the yeast cellular processes. We tested the efect of the Gts1 protein on heat tolerance, sporulation and life-span, by characterizing the phenotypes of transformants with different copy numbers of the gene. We found that the Gts1 protein affects the capacity of heat tolerance in the stationary phase and the speed leading to sporulation in a gene-dose dependent manner, and that both inactivation and overexpression of the gene shortened the life-span of yeast. These results supported the notion that GTS1 affects the biological clock of the yeast S. cerevisiae, although this cannot be definitively concluded because the strain cannot be synchronized with circadian or ultradian rhythms. PMID:8573138

Yaguchi, S; Mitsui, K; Kawabata, K; Xu, Z; Tsurugi, K

1996-01-01

192

C. elegans ortholog of mammalian Ku70 interacts with insulin-like signaling to modulate stress resistance and life span  

PubMed Central

The mammalian Ku heterodimer has important roles in DNA double strand break repair, telomere maintenance, cell cycle checkpoint-arrest, tumor suppression, and cellular stress resistance. To investigate the evolutionarily conserved functions of Ku, we knocked down expression by RNA interference (RNAi) of Ku genes in C. elegans. We found that C. elegans Ku70 (CKU-70) is required for resistance to genotoxic stress, regulates cytotoxic stress responses, and influences aging. The latter effects are dependent on an IGF-1/insulin-like signaling pathway previously shown to affect life span. Reduction of CKU-70 activity amplifies the aging phenotype of long-lived insulin receptor daf-2 mutations in a daf-16-dependent manner. These observations support the view that organismal stress resistance determines life span and Ku70 modulates these effects.

McColl, Gawain; Vantipalli, Maithili C.; Lithgow, Gordon J.

2006-01-01

193

Influence of sources of dietary oils on the life span of stroke-prone spontaneously hypertensive rats  

Microsoft Academic Search

In recent studies, the life span of stroke-prone spontaneously hypertensive (SHRSP) rats was altered by a variety of dietary\\u000a fats. It was relatively shorter in rats fed canola oil as the sole source of fat. The present study was performed to find\\u000a out whether the fatty acid profile and the high content of sulfur compounds in canola oil could modulate

W. M. N. Ratnayake; L. Plouffe; R. Hollywood; M. R. L'Abbé; N. Hidiroglou; G. Sarwar; R. Mueller

2000-01-01

194

Dietary supplementation with Lovaza and krill oil shortens the life span of long-lived F1 mice.  

PubMed

Marine oils rich in ?-3 polyunsaturated fatty acids have been recommended as a preventive treatment for patients at risk for cardiovascular diseases. These oils also are the third most consumed dietary supplement in the USA. However, evidence for their health benefits is equivocal. We tested the daily, isocaloric administration of krill oil (1.17 g oil/kg diet) and Lovaza (Omacor; 4.40 g/kg diet), a pharmaceutical grade fish oil, beginning at 12 months of age, on the life span and mortality-related pathologies of long-lived, male, B6C3F1 mice. The oils were incorporated into the chemically defined American Institute of Nutrition (AIN)-93 M diet. An equivalent volume of soybean oil was removed. Krill oil was 3 % and Lovaza 11 % of the oil in the diets. When their effects were analyzed together, the marine oils significantly shortened life span by 6.6 % (P?=?0.0321; log-rank test) relative to controls. Individually, Lovaza and krill oil non-significantly shortened median life span by 9.8 and 4.7 %, respectively. Lovaza increased the number of enlarged seminal vesicles (7.1-fold). Lovaza and krill oil significantly increased lung tumors (4.1- and 8.2-fold) and hemorrhagic diathesis (3.9- and 3.1-fold). Analysis of serum from treated mice found that Lovaza slightly increased blood urea nitrogen, while krill oil modestly increased bilirubin, triglycerides, and blood glucose levels. Taken together, the results do not support the idea that the consumption of isolated ?-3 fatty acid-rich oils will increase the life span or health of initially healthy individuals. PMID:24816553

Spindler, Stephen R; Mote, Patricia L; Flegal, James M

2014-06-01

195

Growth and life span of the small octopus Octopus tehuelchus in San Matías Gulf (Patagonia): three decades of study  

Microsoft Academic Search

Phenotypic plasticity in response to environmental variability is one of the main characteristics of cephalopods. This study\\u000a compares growth and life span of Octopus tehuelchus in different coastal environments of San Matías Gulf (Patagonia) at three different periods. The progression of maturity\\u000a jointly with modal progression analysis and the detection of hatchlings in the natural environment were used to differentiate

Lorena P. Storero; Matías Ocampo-Reinaldo; Raúl A. González; Maite A. Narvarte

2010-01-01

196

An approach to give prospective life-span of the copper\\/low-density-polyethylene nanocomposite intrauterine device  

Microsoft Academic Search

As a novel copper-containing intrauterine device (IUD), the prospective life-span of the copper\\/low-density-polyethylene (Cu\\/LDPE)\\u000a nanocomposite IUD is very important for the future clinical use and should be given in advance. Here a novel approach, cupric\\u000a ions accelerated release in diluted nitric acid solution and cupric ions concentration release in various volume of simulated\\u000a uterine solution (SUS), is reported to verify

Xianping XiaYing; Ying Tang; Changsheng Xie; Yun Wang; Shuizhou Cai; Changhong Zhu

2011-01-01

197

Comparative characterisation of poly(ADP-ribose) polymerase-1 from two mammalian species with different life span  

Microsoft Academic Search

DNA damage induced in higher eukaryotes by alkylating agents, oxidants or ionising radiation triggers the synthesis of protein-conjugated poly(ADP-ribose) catalysed by poly(ADP-ribose) polymerase-1 (PARP-1). Previously, cellular poly(ADP-ribosyl)ation capacity has been shown to correlate positively with the life span of mammalian species [Proc. Natl. Acad. Sci. USA 89 (1992) 11?759–11?763]. Here, we have tested whether this correlation results from differences in

S Beneke; R Alvarez-Gonzalez; A Bürkle

2000-01-01

198

Ageing in a eusocial insect: molecular and physiological characteristics of life span plasticity in the honey bee  

PubMed Central

Summary Commonly held views assume that ageing, or senescence, represents an inevitable, passive, and random decline in function that is strongly linked to chronological age. In recent years, genetic intervention of life span regulating pathways, for example, in Drosophila as well as case studies in non-classical animal models, have provided compelling evidence to challenge these views. Rather than comprehensively revisiting studies on the established genetic model systems of ageing, we here focus on an alternative model organism with a wild type (unselected genotype) characterized by a unique diversity in longevity – the honey bee. Honey bee (Apis mellifera) life span varies from a few weeks to more than 2 years. This plasticity is largely controlled by environmental factors. Thereby, although individuals are closely related genetically, distinct life histories can emerge as a function of social environmental change. Another remarkable feature of the honey bee is the occurrence of reverted behavioural ontogeny in the worker (female helper) caste. This behavioural peculiarity is associated with alterations in somatic maintenance functions that are indicative of reverted senescence. Thus, although intraspecific variation in organismal life span is not uncommon, the honey bee holds great promise for gaining insights into regulatory pathways that can shape the time-course of ageing by delaying, halting or even reversing processes of senescence. These aspects provide the setting of our review. We will highlight comparative findings from Drosophila melanogaster and Caenorhabditis elegans in particular, and focus on knowledge spanning from molecular- to behavioural-senescence to elucidate how the honey bee can contribute to novel insights into regulatory mechanisms that underlie plasticity and robustness or irreversibility in ageing.

Munch, D.; Amdam, G. V.; Wolschin, F.

2008-01-01

199

Proteotoxicity and the contrasting effects of oxaloacetate and glycerol on Caenorhabditis elegans life span: a role for methylglyoxal?  

PubMed

Because accumulation of altered proteins is the most common biochemical symptom of aging, it is at least possible that such proteotoxicity may cause aging and influence life span. The life span of the nematode worm Caenorhabditis elegans is strongly influenced by changes in the intracellular concentration of methylglyoxal (MG), a putative source of much age-related proteotoxicity and organelle, cellular, and molecular dysfunction. Glycerol has recently been shown to shorten, whereas oxaloacetate has been found to extend, life span in C. elegans. It is suggested here that glycerol and oxaloacetate exert opposing effects on MG formation in C. elegans. It is proposed that, if not secreted by aquaporin, glycerol is converted to glycerol phosphate and then to dihydroxyacetone phosphate (DHAP) via a reaction requiring nicotinamide adenine dinucleotide (NAD(+)). This inhibits operation of the glycerol phosphate cycle in which DHAP is converted into glycerol phosphate, which concomitantly regenerates NAD(+) from NADH, thereby ensuring glycolytic oxidation of glyceraldehyde-3-phosphate (G3P). Because DHAP and G3P spontaneously decompose into MG, and NAD(+) is required for conversion of G3P into phosphoglycerate, the glycerol-induced increased DHAP formation and decreased NAD(+) availability will increase the potential for MG generation. In contrast, oxaloacetate may decrease MG generation by stimulating the operation of the malate-oxaloacetate shuttle, in which oxaloacetate is converted to malate, which regenerates NAD(+) from NADH. By the ensuing G3P oxidation, increased NAD(+) availability will decrease the potential for MG formation. It should be noted that mitochondria are involved in the operation of the above cycle/shuttles and that increased NAD(+) availability also stimulates those sirtuin activities that increase mitogenesis and mitochondrial activity via effects on signal transduction and gene expression, which frequently accompany dietary restriction-induced life span extension. PMID:20645869

Hipkiss, Alan R

2010-10-01

200

Circuit life span in critically ill children on continuous renal replacement treatment: a prospective observational evaluation study  

PubMed Central

Introduction One of the greatest problems with continuous renal replacement therapy (CRRT) is early coagulation of the filters. Few studies have monitored circuit function prospectively. The purpose of this study was to determine the variables associated with circuit life in critically ill children with CRRT. Methods A prospective observational study was performed in 122 children treated with CRRT in a pediatric intensive care unit from 1996 to 2006. Patient and filter characteristics were analyzed to determine their influence on circuit life. Data were collected on 540 filters in 122 patients and an analysis was performed of the 365 filters (67.6%) that were changed due to circuit coagulation. Results The median circuit life was 31 hours (range 1 to 293 hours). A univariate and multivariate logistic regression study was performed to assess the influence of each one of the factors on circuit life span. No significant differences in filter life were found according to age, weight, diagnoses, pump, site of venous access, blood flow rate, ultrafiltration rate, inotropic drug support, or patient outcome. The mean circuit life span was longer when the heparin dose was greater than 20 U/kg per hour (39 versus 29.1 hours; P = 0.008), with hemodiafiltration compared with hemofiltration (34 versus 22.7 hours; P = 0.001), with filters with surface areas of 0.4 to 0.9 m2 (38.2 versus 26.1 hours; P = 0.01), and with a catheter size of 6.5 French or greater (33.0 versus 25.0 hours; P = 0.04). In the multivariate analysis, hemodiafiltration, heparin dose of greater than 20 U/kg per hour, filter surface area of 0.4 m2 or greater, and initial creatinine of less than 2 mg/dL were associated with a filter life of more than 24 and 48 hours. Total effluent rate of greater than 35 mL/kg per hour was associated only with a filter life of more than 24 hours. Conclusion Circuit life span in CRRT in children is short but may be increased by the use of hemodiafiltration, higher heparin doses, and filters with a high surface area.

del Castillo, Jimena; Lopez-Herce, Jesus; Cidoncha, Elena; Urbano, Javier; Mencia, Santiago; Santiago, Maria J; Bellon, Jose M

2008-01-01

201

dSir2 and Dmp53 interact to mediate aspects of CR-dependent life span extension in D. melanogaster  

PubMed Central

Calorie Restriction (CR) is a well established method of extending life span in a variety of organisms. In the fruit fly D. melanogaster, CR is mediated at least in part by activation of dSir2. In mammalian systems, one of the critical targets of Sir2 is the tumor suppressor p53. This deacetylation of p53 by Sir2 leads to inhibition of p53's transcriptional activity. We have recently shown that inhibition of Dmp53 activity in the fly brain through the use of dominant-negative (DN) constructs that inhibit DNA-binding can extend life span. This life span extension appears to be related to CR, as CR and DN-Dmp53 do not display additive effects on life span. Here we report that life span extension by DN-Dmp53 expression is highly dynamic and can be achieved even when DN-Dmp53 is expressed later in life. In addition, we demonstrate that life span extension by activation of dSir2 and DN-Dmp53 expression are not additive. Furthermore, we show that dSir2 physically interacts with Dmp53 and can deacetylate Dmp53-derived peptides. Taken together, our data demonstrate that Dmp53 is a down stream target of dSir2 enzymatic activity and mediates some aspects of the life span extending effects of CR.

Bauer, Johannes H.; Morris, Siti Nur Sarah; Chang, Chengyi; Flatt*, Thomas; Wood, Jason G.; Helfand, Stephen L.

2009-01-01

202

Potentially Traumatic Events at Different Points in the Life Span and Mental Health: Findings From SHARE-Israel  

PubMed Central

This study addressed the association between adversity cumulated at different points in the life span and present mental health. Data of 1,130 participants aged 50+ were drawn from the Israeli component of the Survey of Health, Ageing and Retirement in Europe (SHARE). Measures included an inventory of potentially traumatic events, mental distress (depressive symptoms), and well-being (quality of life, life satisfaction). Adversity reported to have occurred early in life was positively related to mental health (i.e., to lower distress and higher well-being), whereas adversity reported to occur in late life was negatively related (i.e., to higher distress and lower well-being). Additional analyses showed that the positive association between early-life adversity and mental health was mainly restricted to adversity in which the primary harm was to another person (other-oriented adversity). In contrast, the negative association between late-life adversity and mental health was mainly restricted to adversity in which the primary harm was to the self (self-oriented adversity). This study suggests that the differential association between cumulative adversity and mental health is best captured when accounting for both time of occurrence and adversity type.

Shrira, Amit; Shmotkin, Dov; Litwin, Howard

2012-01-01

203

Potentially traumatic events at different points in the life span and mental health: findings from SHARE-Israel.  

PubMed

This study addressed the association between adversity cumulated at different points in the life span and present mental health. Data of 1,130 participants aged 50+ were drawn from the Israeli component of the Survey of Health, Ageing and Retirement in Europe (SHARE). Measures included an inventory of potentially traumatic events, mental distress (depressive symptoms), and well-being (quality of life, life satisfaction). Adversity reported to have occurred early in life was positively related to mental health (i.e., to lower distress and higher well-being), whereas adversity reported to occur in late life was negatively related (i.e., to higher distress and lower well-being). Additional analyses showed that the positive association between early-life adversity and mental health was mainly restricted to adversity in which the primary harm was to another person (other-oriented adversity). In contrast, the negative association between late-life adversity and mental health was mainly restricted to adversity in which the primary harm was to the self (self-oriented adversity). This study suggests that the differential association between cumulative adversity and mental health is best captured when accounting for both time of occurrence and adversity type. PMID:22506527

Shrira, Amit; Shmotkin, Dov; Litwin, Howard

2012-04-01

204

Stability and change in affective experience across the adult life span: analyses with a national sample from Germany.  

PubMed

Using cross-sectional and longitudinal data from a national sample spanning the adult life span, age differences in anger and sadness were explored. The cross-sectional and longitudinal findings consistently suggest that the frequency of anger increases during young adulthood, but then shows a steady decrease until old age. By contrast, the frequency of sadness remains stable over most of adulthood and begins to increase in old age. In addition, the effects of age on happiness were investigated; the cross-sectional evidence speaks for a steady decrease in happiness across age groups, but within-person decline in happiness was only evident in old age. Together the findings provide further evidence for multidirectional age differences in affective experience and suggest that the overall quality of affective experience may deteriorate in old age. PMID:23914760

Kunzmann, Ute; Richter, David; Schmukle, Stefan C

2013-12-01

205

COPEPOD REPRODUCTIVE STRATEGIES: LIFE-HISTORY THEORY, PHYLOGENETIC PATTERN AND INVASION OF INLAND WATERS. (R824771)  

EPA Science Inventory

Abstract Life-history theory predicts that different reproductive strategies should evolve in environments that differ in resource availability, mortality, seasonality, and in spatial or temporal variation. Within a population, the predicted optimal strategy is driven ...

206

The paradox of the short life span of organisms with long telomeres: A possible solution to this paradox  

SciTech Connect

Earlier we proposed an idea about the direct proportional dependence between the length of buffer DNA at the ends of chromosomes, i.e., telomeric DNA, and the life span of organisms. In these publications, we predicted the phenomenon of shortening of telomeric DNA as a result of under-replication (incomplete replication) of terminal DNA sequences. In this study, we try to demonstrate that this shortening of telomeric DNA may indeed be a leading factor in the process of fibroblast aging. 12 refs.

Olovnikov, A.M. [Semenov Institute of Chemical Physics, Moscow (Russian Federation)

1995-07-01

207

Fullness of Life as Minimal Unit: Science, Technology, Engineering, and Mathematics (STEM) Learning across the Life Span  

ERIC Educational Resources Information Center

Challenged by a National Science Foundation-funded conference, 2020 Vision: The Next Generation of STEM Learning Research, in which participants were asked to recognize science, technology, engineering, and mathematics (STEM) learning as lifelong, life-wide, and life-deep, we draw upon 20 years of research across the lifespan to propose a new way…

Roth, Wolff-Michael; Van Eijck, Michiel

2010-01-01

208

Ethical concerns in the community about technologies to extend human life span.  

PubMed

Debates about the ethical and social implications of research that aims to extend human longevity by intervening in the ageing process have paid little attention to the attitudes of members of the general public. In the absence of empirical evidence, conflicting assumptions have been made about likely public attitudes towards life-extension. In light of recent calls for greater public involvement in such discussions, this target article presents findings from focus groups and individual interviews which investigated whether members of the general public identify ethical issues surrounding life-extension, and if so, what these ethical issues are? In this study, while some participants were concerned primarily with the likely personal consequences of life-extension, for others the question of whether or not to pursue interventions to extend longevity, and how they should be implemented, clearly raised important ethical issues, many of which have been prominent in debates among bioethicists. PMID:20013509

Partridge, Brad; Underwood, Mair; Lucke, Jayne; Bartlett, Helen; Hall, Wayne

2009-12-01

209

Life span and disability: a cross sectional comparison of Russian and Swedish community based data  

Microsoft Academic Search

Objectives To compare levels of disability (in terms of physical function and self rated health) among middle aged and elderly people in Russia and Sweden, a country with high life expectancy. Design Cross sectional study. Setting General population of the Russian Federation and of two counties in southern Sweden. Participants Randomly selected men and women in Sweden (n = 9489)

Martin Bobak; Margareta Kristenson; Hynek Pikhart; Michael Marmot

2004-01-01

210

Candidate genes affecting Drosophila life span identified by integrating microarray gene expression analysis and QTL mapping  

Microsoft Academic Search

The current increase in life expectancy observed in industrialized societies underscores the need to achieve a better understanding of the aging process that could help the development of effective strategies to achieve healthy aging. This will require not only identifying genes involved in the aging process, but also understanding how their effects are modulated by environmental factors, such as dietary

Chao-Qiang Lai; Laurence D. Parnell; Richard F. Lyman; Jose M. Ordovas; Trudy F. C. Mackay

2007-01-01

211

Life Span as the Measure of Performance and Learning in a Business Gaming Simulation  

ERIC Educational Resources Information Center

This study applies the learning curve method of measuring learning to participants of a computer-assisted business gaming simulation that includes a multiple-life-cycle feature. The study involved 249 participants. It verified the workability of the feature and estimated the participants' rate of learning at 17.4% for every doubling of experience.…

Thavikulwat, Precha

2012-01-01

212

Assimilation of endogenous nicotinamide riboside is essential for calorie restriction-mediated life span extension in Saccharomyces cerevisiae.  

PubMed

NAD(+) (nicotinamide adenine dinucleotide) is an essential cofactor involved in various biological processes including calorie restriction-mediated life span extension. Administration of nicotinamide riboside (NmR) has been shown to ameliorate deficiencies related to aberrant NAD(+) metabolism in both yeast and mammalian cells. However, the biological role of endogenous NmR remains unclear. Here we demonstrate that salvaging endogenous NmR is an integral part of NAD(+) metabolism. A balanced NmR salvage cycle is essential for calorie restriction-induced life span extension and stress resistance in yeast. Our results also suggest that partitioning of the pyridine nucleotide flux between the classical salvage cycle and the NmR salvage branch might be modulated by the NAD(+)-dependent Sir2 deacetylase. Furthermore, two novel deamidation steps leading to nicotinic acid mononucleotide and nicotinic acid riboside production are also uncovered that further underscore the complexity and flexibility of NAD(+) metabolism. In addition, utilization of extracellular nicotinamide mononucleotide requires prior conversion to NmR mediated by a periplasmic phosphatase Pho5. Conversion to NmR may thus represent a strategy for the transport and assimilation of large nonpermeable NAD(+) precursors. Together, our studies provide a molecular basis for how NAD(+) homeostasis factors confer metabolic flexibility. PMID:19416965

Lu, Shu-Ping; Kato, Michiko; Lin, Su-Ju

2009-06-19

213

Bmi-1 extends the life span of normal human oral keratinocytes by inhibiting the TGF-{beta} signaling  

SciTech Connect

We previously demonstrated that Bmi-1 extended the in vitro life span of normal human oral keratinocytes (NHOK). We now report that the prolonged life span of NHOK by Bmi-1 is, in part, due to inhibition of the TGF-{beta} signaling pathway. Serial subculture of NHOK resulted in replicative senescence and terminal differentiation and activation of TGF-{beta} signaling pathway. This was accompanied with enhanced intracellular and secreted TGF-{beta}1 levels, phosphorylation of Smad2/3, and increased expression of p15{sup INK4B} and p57{sup KIP2}. An ectopic expression of Bmi-1 in NHOK (HOK/Bmi-1) decreased the level of intracellular and secreted TGF-{beta}1 induced dephosphorylation of Smad2/3, and diminished the level of p15{sup INK4B} and p57{sup KIP2}. Moreover, Bmi-1 expression led to the inhibition of TGF-{beta}-responsive promoter activity in a dose-specific manner. Knockdown of Bmi-1 in rapidly proliferating HOK/Bmi-1 and cancer cells increased the level of phosphorylated Smad2/3, p15{sup INK4B}, and p57{sup KIP2}. In addition, an exposure of senescent NHOK to TGF-{beta} receptor I kinase inhibitor or anti-TGF-{beta} antibody resulted in enhanced replicative potential of cells. Taken together, these data suggest that Bmi-1 suppresses senescence of cells by inhibiting the TGF-{beta} signaling pathway in NHOK.

Kim, Reuben H., E-mail: rkim@dentistry.ucla.edu [UCLA School of Dentistry, Los Angeles, CA 90095 (United States); UCLA Dental Research Institute, Los Angeles, CA 90095 (United States); UCLA Jonsson Comprehensive Cancer Center, Los Angeles, CA 90095 (United States); Lieberman, Mark B.; Lee, Rachel [UCLA School of Dentistry, Los Angeles, CA 90095 (United States)] [UCLA School of Dentistry, Los Angeles, CA 90095 (United States); Shin, Ki-Hyuk [UCLA School of Dentistry, Los Angeles, CA 90095 (United States) [UCLA School of Dentistry, Los Angeles, CA 90095 (United States); UCLA Dental Research Institute, Los Angeles, CA 90095 (United States); UCLA Jonsson Comprehensive Cancer Center, Los Angeles, CA 90095 (United States); Mehrazarin, Shebli; Oh, Ju-Eun [UCLA School of Dentistry, Los Angeles, CA 90095 (United States)] [UCLA School of Dentistry, Los Angeles, CA 90095 (United States); Park, No-Hee [UCLA School of Dentistry, Los Angeles, CA 90095 (United States) [UCLA School of Dentistry, Los Angeles, CA 90095 (United States); UCLA Dental Research Institute, Los Angeles, CA 90095 (United States); UCLA Jonsson Comprehensive Cancer Center, Los Angeles, CA 90095 (United States); David Geffen School of Medicine at UCLA, Los Angeles, CA 90095 (United States); Kang, Mo K., E-mail: mkang@dentistry.ucla.edu [UCLA School of Dentistry, Los Angeles, CA 90095 (United States); UCLA Dental Research Institute, Los Angeles, CA 90095 (United States); UCLA Jonsson Comprehensive Cancer Center, Los Angeles, CA 90095 (United States)

2010-10-01

214

Allometric dependence of the life span of mammal erythrocytes on thermal stability and sphingomyelin content of plasma membranes.  

PubMed

Thermal stability of erythrocyte membrane is a measure for its ability to maintain permeability barrier at deleterious conditions. Hence, it could impact the resistance of erythrocytes against detrimental factors in circulation. In this study the thermostability of erythrocyte membranes was expressed by the temperature, T(go), at which the transmembrane gradient of ion concentration rapidly dissipated during transient heating. T(go) is the inducing temperature of the membrane transition that activated passive ion permeability at hyperthermia causing thermal hemolysis. A good allometric correlation of T(go) to the resistance against thermal hemolysis and the life span of erythrocytes were found for 13 mammals; sheep, cow, goat, dog, horse, man, rabbit, pig, cat, hamster, guinea pig, rat, and mouse. For the same group, the values of T(go) were strictly related to the sphingomyelin content of erythrocyte membranes. The residual ion permeability, P, was temperature activated from 38 to 57 degrees C with activation energy of 250+/-15 kJ/mol that strongly differed from that below 37 degrees C. The projected value of P at 37 degrees C was about half that of residual physiological permeability for Na+ and K+ that build ground for possible explanation of the life span vs membrane thermostability allometric correlation. PMID:17398129

Ivanov, Ivan Tanev

2007-08-01

215

Dependence of the meridional motions of sunspot groups on life spans and age of the groups, and on the phase of the solar cycle  

Microsoft Academic Search

We have analyzed data on sunspot groups compiled during 1874–1981 and investigated the following: (i) dependence of the `initial' meridional motion (vini(t)) of sunspot groups on the life span (t) of the groups in the range 2–12 days, (ii) dependence of the meridional motion (v(t)) of sunspot groups of life spans 10–12 days on the age (t) of the spot groups,

J. Javaraiah

1999-01-01

216

Review of the literature and suggestions for the design of rodent survival studies for the identification of compounds that increase health and life span  

Microsoft Academic Search

Much of the literature describing the search for agents that increase the life span of rodents was found to suffer from confounds.\\u000a One-hundred-six studies, absent 20 contradictory melatonin studies, of compounds or combinations of compounds were reviewed.\\u000a Only six studies reported both life span extension and food consumption data, thereby excluding the potential effects of caloric\\u000a restriction. Six other studies

Stephen Richard Spindler

217

Can we increase our life span? The role of nuclear gerontology.  

PubMed

Elderly people, those above 60 or 65 years old differ from younger people in many ways. Nuclear medicine can play a role in the diagnosis of diseases of the elderly and thus help, in social adjustment and in care for the elderly people. The question is why adult stem cells have a certain limit of reproduction, since their DNA in a normal physical environment can theoretically live very much longer. The elderly are prone to suffer more diseases than the young. It is important that the elderly should use water soluble and not lipid soluble drugs. There are many more to write about the elderly. We have tried to be brief in order to show the importance of using nuclear medicine in gerontology. Let us mention here that the word gerontology means in greek "talk about the elderly" (gerontas is the old man and logy is to talk about). Elderly people are a large part of our society and we do have every reason, every interest and responsibility to keep this part of our society healthy, useful and productive. PMID:21193870

Grammaticos, Philip

2010-01-01

218

Recent Progress in Metabolic Signaling Pathways Regulating Aging and Life Span  

PubMed Central

The NIH Summit, Advances in Geroscience: Impact on Health Span and Chronic Disease, discusses several aspects of cellular degeneration that underlie susceptibility to chronic aging-associated diseases, morbidity, and mortality. In particular, the session on Metabolism focuses on the interrelationship between signal transduction, intermediary metabolism, and metabolic products and byproducts that contribute to pathophysiologic phenotypes and detrimental effects that occur during the aging process, thus leading to susceptibility to disease. Although it is well established that many metabolic pathways (ie, oxidative phosphorylation, insulin-stimulated glucose uptake) decline with age, it often remains uncertain if these are a cause or consequence of the aging process. Moreover, the mechanisms accounting for the decline in metabolic function remain enigmatic. Several novel and unexpected concepts are emerging that will help to define the roles of altered metabolic control in the degenerative mechanisms of aging. This brief review summarizes several of the topics to be discussed in the metabolism of aging session (http://www.geron.org/About%20Us/nih-geroscience-summit).

2014-01-01

219

Estimating the life-span of oligodendrocytes from clonal data on their development in cell culture.  

PubMed

This paper presents a new method to analyze clonal data on oligodendrocyte development in cell culture. The process of oligodendrocyte generation from precursor cells is modelled as a multi-type Bellman-Harris branching process as suggested in an earlier paper [K. Boucher, A. Zorin, A.Y. Yakovlev, M. Mayer-Proschel, M. Noble, An alternative stochastic model of generation of oligodendrocytes in cell culture, J. Math. Biol. 43 (2001) 22]. This model has been extended to allow for death of oligodendrocytes as well as a dissimilar distribution of the first mitotic cycle duration as compared to the subsequent cycles of precursor cells, which lengths are assumed to be independent and identically distributed random variables. Since the time-span of oligodendrocytes is not directly observable in clonal data, plausible parametric assumptions are invoked to make estimation problems tractable. In particular, the time to cell death follows a two-parameter gamma distribution, while the lapse of time between the event of cell death and the event of cell disintegration is assumed to be exponentially distributed. A simulated pseudo maximum likelihood method for estimation of model parameters has been developed using simulation-based approximations of the expected numbers and variance-covariance matrices for different types of cells. Finite sample properties of the estimation procedure are studied by computer simulations. The proposed method is illustrated with an analysis of the clonal development of O-2A progenitor cells isolated from the rat optic nerve and the corpus callosum. PMID:15748733

Hyrien, Ollivier; Mayer-Pröschel, Margot; Noble, Mark; Yakovlev, Andrei

2005-02-01

220

Recent progress in metabolic signaling pathways regulating aging and life span.  

PubMed

The NIH Summit, Advances in Geroscience: Impact on Health Span and Chronic Disease, discusses several aspects of cellular degeneration that underlie susceptibility to chronic aging-associated diseases, morbidity, and mortality. In particular, the session on Metabolism focuses on the interrelationship between signal transduction, intermediary metabolism, and metabolic products and byproducts that contribute to pathophysiologic phenotypes and detrimental effects that occur during the aging process, thus leading to susceptibility to disease. Although it is well established that many metabolic pathways (ie, oxidative phosphorylation, insulin-stimulated glucose uptake) decline with age, it often remains uncertain if these are a cause or consequence of the aging process. Moreover, the mechanisms accounting for the decline in metabolic function remain enigmatic. Several novel and unexpected concepts are emerging that will help to define the roles of altered metabolic control in the degenerative mechanisms of aging. This brief review summarizes several of the topics to be discussed in the metabolism of aging session (http://www.geron.org/About%20Us/nih-geroscience-summit). PMID:24833582

Newgard, Christopher B; Pessin, Jeffrey E

2014-06-01

221

The malate-aspartate NADH shuttle components are novel metabolic longevity regulators required for calorie restriction-mediated life span extension in yeast.  

PubMed

Recent studies suggest that increased mitochondrial metabolism and the concomitant decrease in NADH levels mediate calorie restriction (CR)-induced life span extension. The mitochondrial inner membrane is impermeable to NAD (nicotinamide adenine dinucleotide, oxidized form) and NADH, and it is unclear how CR relays increased mitochondrial metabolism to multiple cellular pathways that reside in spatially distinct compartments. Here we show that the mitochondrial components of the malate-aspartate NADH shuttle (Mdh1 [malate dehydrogenase] and Aat1 [aspartate amino transferase]) and the glycerol-3-phosphate shuttle (Gut2, glycerol-3-phosphate dehydrogenase) are novel longevity factors in the CR pathway in yeast. Overexpressing Mdh1, Aat1, and Gut2 extend life span and do not synergize with CR. Mdh1 and Aat1 overexpressions require both respiration and the Sir2 family to extend life span. The mdh1Deltaaat1Delta double mutation blocks CR-mediated life span extension and also prevents the characteristic decrease in the NADH levels in the cytosolic/nuclear pool, suggesting that the malate-aspartate shuttle plays a major role in the activation of the downstream targets of CR such as Sir2. Overexpression of the NADH shuttles may also extend life span by increasing the metabolic fitness of the cells. Together, these data suggest that CR may extend life span and ameliorate age-associated metabolic diseases by activating components of the NADH shuttles. PMID:18381895

Easlon, Erin; Tsang, Felicia; Skinner, Craig; Wang, Chen; Lin, Su-Ju

2008-04-01

222

Human evolution, life history theory, and the end of biological reproduction.  

PubMed

Throughout primate history there have been three major life history transitions towards increasingly delayed sexual maturation and biological reproduction, as well as towards extended life expectancy. Monkeys reproduce later and live longer than do prosimians, apes reproduce later and live longer than do monkeys, and humans reproduce later and live longer than do apes. These life history transitions are connected to increased encephalization. During the last life history transition from apes to humans, increased encephalization co-evolved with increased dependence on cultural knowledge for energy acquisition. This led to a dramatic pressure for more energy investment in growth over current biological reproduction. Since the industrial revolution socioeconomic development has led to even more energy being devoted to growth over current biological reproduction. I propose that this is the beginning of an ongoing fourth major primate life history transition towards completely delayed biological reproduction and an extension of the evolved human life expectancy. I argue that the only fundamental difference between this primate life history transition and previous life history transitions is that this transition is being driven solely by cultural evolution, which may suggest some deeper evolutionary transition away from biological evolution is already in the process of occurring. PMID:24852016

Last, Cadell

2014-01-01

223

Sex effects on life span and senescence in the wild when dates of birth and death are unknown.  

PubMed

Males and females allocate and schedule reproductive effort in very different ways. Because the timing and amount of reproductive effort influence survival and thus the optimization of life histories, mortality and senescence are predicted to be sex specific. However, age-specific mortality rates of wild animals are often difficult to quantify in natural populations. Studies that report mortality rates from natural populations are, therefore, almost entirely confined to long-lived, easy-to-track species such as large mammals and birds. Here, we employ a novel approach using capture-mark-recapture data from a wild population of black field crickets (Teleogryllus commodus) to test for sex differences in demographic aging. In this species, the age of captured adults cannot be readily determined, and animals cannot be reliably captured or observed every night, resulting in demographic data on individuals whose dates of birth and death are unknown. We implement a recently developed life-table analysis for wild-caught individuals of unknown age, in combination with a well-established capture-mark-recapture methodology that models probabilistic dates of death. This unified analytical framework makes it possible to test for aging in wild, hard-to-track animals. Using these methods to fit Gompertz models of age-specific mortality, we show that male crickets have higher mortality rates throughout life than female crickets. Furthermore, males and females both exhibit increasing mortality rates with age, indicating senescence, but the rate of senescence is not sex specific. Thus, observed sex differences in longevity are probably due to differences in baseline mortality rather than aging. Our findings illustrate the complexity of the relationships between sex, background mortality, and senescence rate in wild populations, showing that the elevated mortality rate of males need not be coupled with an elevated rate of aging. PMID:19569384

Zajitschek, Felix; Brassil, Chad E; Bonduriansky, Russell; Brooks, Robert C

2009-06-01

224

Cell specific radiation dosimetry in skeleton from life-span carcinogenesis studies  

SciTech Connect

The osteogenic sarcoma is the dominant life-threatening pathology in lifespan studies of beagles exposed to alpha-emitting bone-seeking radionuclides. It was deduced from these studies that certain skeletal sites are more prone to develop tumors. This project sought to determine the bone cells at risk and their cell-specific radiation dose. The cell-specific radiation dose values are related to loss and high Ra-226 and Pu-239 induced osteogenic sarcoma sites, to test different dose response hypothesis and predict the extent of effects in humans.

Webster, S.S.J.

1993-04-05

225

Cell specific radiation dosimetry in skeleton from life-span carcinogenesis studies. Final report  

SciTech Connect

The osteogenic sarcoma is the dominant life-threatening pathology in lifespan studies of beagles exposed to alpha-emitting bone-seeking radionuclides. It was deduced from these studies that certain skeletal sites are more prone to develop tumors. This project sought to determine the bone cells at risk and their cell-specific radiation dose. The cell-specific radiation dose values are related to loss and high Ra-226 and Pu-239 induced osteogenic sarcoma sites, to test different dose response hypothesis and predict the extent of effects in humans.

Webster, S.S.J.

1993-04-05

226

New Strategies to Prolong the In Vivo Life Span of Iron-Based Contrast Agents for MRI  

PubMed Central

Superparamagnetic iron oxide (SPIO) and ultra small superparamagnetic iron oxide (USPIO) nanoparticles have been developed as magnetic resonance imaging (MRI) contrast agents. Iron oxide nanoparticles, that become superparamagnetic if the core particle diameter is ~ 30nm or less, present R1 and R2 relaxivities which are much higher than those of conventional paramagnetic gadolinium chelates. Generally, these magnetic particles are coated with biocompatible polymers that prevent the agglomeration of the colloidal suspension and improve their blood distribution profile. In spite of their potential as MRI blood contrast agents, the biomedical application of iron oxide nanoparticles is still limited because of their intravascular half-life of only few hours; such nanoparticles are rapidly cleared from the bloodstream by macrophages of the reticulo-endothelial system (RES). To increase the life span of these MRI contrast agents in the bloodstream we proposed the encapsulation of SPIO nanoparticles in red blood cells (RBCs) through the transient opening of cell membrane pores. We have recently reported results obtained by applying our loading procedure to several SPIO nanoparticles with different chemical physical characteristics such as size and coating agent. In the current investigation we showed that the life span of iron-based contrast agents in the mice bloodstream was prolonged to 12 days after the intravenous injection of murine SPIO-loaded RBCs. Furthermore, we developed an animal model that implicates the pretreatment of animals with clodronate to induce a transient suppression of tissue macrophages, followed by the injection of human SPIO-loaded RBCs which make it possible to encapsulate nanoparticle concentrations (5.3-16.7mM Fe) higher than murine SPIO-loaded RBCs (1.4-3.55mM Fe). The data showed that, when human RBCs are used as more capable SPIO nanoparticle containers combined with a depletion of tissue macrophages, Fe concentration in animal blood is 2-3 times higher than iron concentration obtained by the use of murine SPIO-loaded RBCs.

Antonelli, Antonella; Sfara, Carla; Battistelli, Serafina; Canonico, Barbara; Arcangeletti, Marcella; Manuali, Elisabetta; Salamida, Sonia; Papa, Stefano; Magnani, Mauro

2013-01-01

227

Sickle Cell Disease: An Opportunity for Palliative Care across the Life Span  

PubMed Central

Sickle cell disease is a chronic illness that impacts patients physically and emotionally and can do so at an early age. An ecological model of palliative care that involves improved communication among the health care team, patients, and their families can be beneficial. Open and honest communication regarding advance care planning, disease management, relief of pain and other symptoms, and bereavement and grief are all important for the patient, family, and health care team. Given the multiple acute and chronic complications of sickle cell disease, an approach to care that is holistic and comprehensive may help to improve a patient’s biological function and the perceived health, functional status, and quality of life of the patient and family.

Johnson, Bonnye; Mack, A. Kyle; Labotka, Richard; Molokie, Robert E.

2010-01-01

228

Similar causes of various reproductive disorders in early life  

PubMed Central

During the past few decades, scientific evidence has been accumulated concerning the possible adverse effects of the exposure to environmental chemicals on the well-being of wildlife and human populations. One large and growing group of such compounds of anthropogenic or natural origin is referred to as endocrine-disrupting chemicals (EDCs), due to their deleterious action on the endocrine system. This concern was first focused on the control of reproductive function particularly in males, but has later been expanded to include all possible endocrine functions. The present review describes the underlying physiology behind the cascade of developmental events that occur during sexual differentiation of males and the specific role of androgen in the masculinization process and proper organogenesis of the external male genitalia. The impact of the genetic background, environmental exposures and lifestyle factors in the etiology of hypospadias, cryptorchidism and testicular cancer are reviewed and the possible role of EDCs in the development of these reproductive disorders is discussed critically. Finally, the possible direct and programming effects of exposures in utero to widely use therapeutic compounds, environmental estrogens and other chemicals on the incidence of reproductive abnormalities and poor semen quality in humans are also highlighted.

Svechnikov, Konstantin; Stukenborg, Jan-Bernd; Savchuck, Iuliia; Soder, Olle

2014-01-01

229

Axenic growth up-regulates mass-specific metabolic rate, stress resistance, and extends life span in Caenorhabditis elegans.  

PubMed

Culture in axenic medium causes two-fold increases in the length of development and adult life span in Caenorhabditis elegans. We asked whether axenic medium imposes dietary restriction (ADR), and causes changes in metabolic activity and stress resistance. Eat mutants, which have a reduced food intake, were studied in parallel with wild-type worms to assess potential synergistic actions of axenic culture and food restriction. We found that axenic culture enhances metabolic activity as assessed by mass-specific oxygen consumption rate and heat production. Axenic culture also caused higher activities of the antioxidant enzymes superoxide dismutase and catalase, and led to increased resistance to high temperature, which was further exacerbated by mutation in eat-2. These results show that axenic medium up-regulates a variety of somatic maintenance functions including oxidative and thermal stress resistance and that food restriction due to axenic growth and to mutation in eat-2 are very similar but not identical. PMID:12559406

Houthoofd, Koen; Braeckman, Bart P; Lenaerts, Isabelle; Brys, Kristel; De Vreese, Annemie; Van Eygen, Sylvie; Vanfleteren, Jacques R

2002-12-01

230

Estimation of the Life Span of Red Blood Cells in the Growing Animal in Different Nutritional States  

PubMed Central

In this study the model of Shemin and Rittenberg for estimating the life span of red blood cells was extended so that non-steady-state conditions, exemplified by growth or changing physiological states, might be considered. The parameters were estimated by use of the modified Gauss-Newton method. The biological data that were used came from growing sheep in different physiological states with regard to copper. The model was extended to include changes in total blood hemin and changes in blood hemin synthesis that may occur with time. In the present study a linear function was taken as a first approximation. The model appeared to be a sufficiently good approximation in the study reported herein. It was found, however, that the parameters associated with changes in hemin should be estimated from ancillary measurements such as blood volume, Hb, body weight, etc., in order to obtain a good fit or definition of the model.

Carter, Melvin W.; Matrone, Gennard; Metzler, Carl

1965-01-01

231

The Effect of ACP?-ADA? Genetic Interaction on Human Life Span.  

PubMed

Acid phosphatase (ACP?) is a polymorphic enzyme that catalyzes the conversion of flavin-mononucleotide (FMN) to riboflavin and regulates the cellular concentration of flavin-adenine-dinucleotide (FAD) and, consequently, energy metabolism. Its activity is modulated by adenosine deaminase locus 1 (ADA?) genotype. The aim of our work is to verify whether individuals with a high proportion of ACP? f-isozyme and carrying the ADA?*2 allele, displaying the highest phosphatase activity, may have a higher life expectancy. Genomic DNA was extracted from the peripheral blood of 569 females and 509 males (18 to 106 years of age) randomly recruited from Central Italy. These samples were subdivided into three sex-specific age groups (the ages of women are in square bracket): Class 1: age <66 [<73]; Class 2: ages 66 to 88 [73 to 91]; Class 3: age >88 [>91]. ACP?and ADA? singlenucleotide polymorphisms (SNPs) were genotyped by restriction fragment length polymorphism-polymerase chain reaction (RFLP-PCR) methods and statistical analyses were performed with SPSS 14.0. The results showed a larger proportion of Class 3 individuals displaying high ACP? f-isozyme concentration and carrying the ADA?*2 allele than those individuals of Class 2 and Class 2 plus Class 1. Thus, we postulate that in Class 3 individuals the high phosphatase activity, resulting from the combined presence of high ACP? f-isozyme concentration and the ADA?*2 allele, lowers the rate of glycolysis that may reduce the amount of metabolic calories and, in turn, activate Sirtuin genes that protect cells against age-related diseases. PMID:23959645

Lucarini, Nazzareno; Napolioni, Valerio; Magrini, Andrea; Gloria, Fulvia

2012-12-01

232

Genome-Wide Screen in Saccharomyces cerevisiae Identifies Vacuolar Protein Sorting, Autophagy, Biosynthetic, and tRNA Methylation Genes Involved in Life Span Regulation  

PubMed Central

The study of the chronological life span of Saccharomyces cerevisiae, which measures the survival of populations of non-dividing yeast, has resulted in the identification of homologous genes and pathways that promote aging in organisms ranging from yeast to mammals. Using a competitive genome-wide approach, we performed a screen of a complete set of approximately 4,800 viable deletion mutants to identify genes that either increase or decrease chronological life span. Half of the putative short-/long-lived mutants retested from the primary screen were confirmed, demonstrating the utility of our approach. Deletion of genes involved in vacuolar protein sorting, autophagy, and mitochondrial function shortened life span, confirming that respiration and degradation processes are essential for long-term survival. Among the genes whose deletion significantly extended life span are ACB1, CKA2, and TRM9, implicated in fatty acid transport and biosynthesis, cell signaling, and tRNA methylation, respectively. Deletion of these genes conferred heat-shock resistance, supporting the link between life span extension and cellular protection observed in several model organisms. The high degree of conservation of these novel yeast longevity determinants in other species raises the possibility that their role in senescence might be conserved.

Shamalnasab, Mehrnaz; Galbani, Abdulaye; Wei, Min; Giaever, Guri; Nislow, Corey; Longo, Valter D.

2010-01-01

233

Life Span Extension by Calorie Restriction Depends on Rim15 and Transcription Factors Downstream of Ras/PKA, Tor, and Sch9  

PubMed Central

Calorie restriction (CR), the only non-genetic intervention known to slow aging and extend life span in organisms ranging from yeast to mice, has been linked to the down-regulation of Tor, Akt, and Ras signaling. In this study, we demonstrate that the serine/threonine kinase Rim15 is required for yeast chronological life span extension caused by deficiencies in Ras2, Tor1, and Sch9, and by calorie restriction. Deletion of stress resistance transcription factors Gis1 and Msn2/4, which are positively regulated by Rim15, also caused a major although not complete reversion of the effect of calorie restriction on life span. The deletion of both RAS2 and the Akt and S6 kinase homolog SCH9 in combination with calorie restriction caused a remarkable 10-fold life span extension, which, surprisingly, was only partially reversed by the lack of Rim15. These results indicate that the Ras/cAMP/PKA/Rim15/Msn2/4 and the Tor/Sch9/Rim15/Gis1 pathways are major mediators of the calorie restriction-dependent stress resistance and life span extension, although additional mediators are involved. Notably, the anti-aging effect caused by the inactivation of both pathways is much more potent than that caused by CR.

Hu, Jia; Ge, Huanying; Cheng, Chao; Li, Lei; Longo, Valter D

2008-01-01

234

Living the dream? A qualitative retrospective study exploring the role of adolescent aspirations across the life span.  

PubMed

There is a lack of longitudinal research linking adolescent career aspirations to adult outcomes other than career and income attainment. Drawing on Nurmi's (2004) and Salmela-Aro, Aunola, and Nurmi's (2007) life-span model of motivation and using quantitative survey data at ages 16, 23, 33, 42, and 50 years, combined with retrospective interview data at age 50 (collected from 25 members of a British cohort study born in 1958), we aimed to gain a more rounded understanding of the role that adolescent career aspirations play in shaping not only adult career development but also adult identities and well-being. Twenty-two of the 25 participants fulfilled their adolescent career aspirations later in life through achieving (a) the exact career they aspired to or (b) the social status of the career they aspired to. In relation to adult personal identity and well-being, the findings suggest that what matters is not just whether a person aims high at age 16 (i.e., to be a professional or a manager) but also whether the person remembers having strong or meaningful career aspirations. Further themes, gender differences, and implications for policy and future research are discussed. PMID:22329387

Ashby, Julie S; Schoon, Ingrid

2012-11-01

235

Implications of Extreme Life Span in Clonal Organisms: Millenary Clones in Meadows of the Threatened Seagrass Posidonia oceanica  

PubMed Central

The maximum size and age that clonal organisms can reach remains poorly known, although we do know that the largest natural clones can extend over hundreds or thousands of metres and potentially live for centuries. We made a review of findings to date, which reveal that the maximum clone age and size estimates reported in the literature are typically limited by the scale of sampling, and may grossly underestimate the maximum age and size of clonal organisms. A case study presented here shows the occurrence of clones of slow-growing marine angiosperm Posidonia oceanica at spatial scales ranging from metres to hundreds of kilometres, using microsatellites on 1544 sampling units from a total of 40 locations across the Mediterranean Sea. This analysis revealed the presence, with a prevalence of 3.5 to 8.9%, of very large clones spreading over one to several (up to 15) kilometres at the different locations. Using estimates from field studies and models of the clonal growth of P. oceanica, we estimated these large clones to be hundreds to thousands of years old, suggesting the evolution of general purpose genotypes with large phenotypic plasticity in this species. These results, obtained combining genetics, demography and model-based calculations, question present knowledge and understanding of the spreading capacity and life span of plant clones. These findings call for further research on these life history traits associated with clonality, considering their possible ecological and evolutionary implications.

Arnaud-Haond, Sophie; Duarte, Carlos M.; Diaz-Almela, Elena; Marba, Nuria; Sintes, Tomas; Serrao, Ester A.

2012-01-01

236

Insulin-like growth factor-2 genotype, fat-free mass, and muscle performance across the adult life span.  

PubMed

The influence of insulin-like growth factor-2 (IGF2) genotype on total body fat-free mass (FFM), muscle strength, and sustained power (SP) was evaluated repeatedly at approximately 2-yr intervals in two cohorts from the Baltimore Longitudinal Study of Aging. Cohort 1 was comprised of 94 men tested for isometric grip strength and SP. Cohort 2 was comprised of 246 men and 239 women tested for total body FFM and isokinetic peak torque. Subjects were retrospectively genotyped for the IGF2 gene's ApaI polymorphism. Differences between genotype groups for total FFM, strength, and SP at first visit, at peak age (35 yr), at age 65, and across the adult age span were analyzed using either two-sample t-tests or mixed-effects models, depending on the specific comparisons made. Isokinetic arm strength at the time of first visit was lower in A/A men than in G/G men (P < 0.05). Compared with G/G women, A/A women had lower total body FFM, lower isokinetic arm and leg strength at the time of first visit, and lower values at age 35 (all P < 0.05) for these muscle phenotypes. Furthermore, this difference between the genotype groups was maintained at age 65 and across the adult age span (P < 0.05). No genotype-associated differences in rates of loss of grip strength or SP were found in cohort 1. These results from cohort 2 support the hypothesis that variation within a gene known to influence developing muscle affects muscle mass and muscle function in later life. PMID:15298990

Schrager, Matthew A; Roth, Stephen M; Ferrell, Robert E; Metter, E Jeffrey; Russek-Cohen, Estelle; Lynch, Nicole A; Lindle, Rosemary S; Hurley, Ben F

2004-12-01

237

Suicide: life span considerations.  

PubMed

Although the daily hassles of living are challenging and stressful to most people, suicide is a cry for help that often reflects tremendous emotional pain and distress. When one's normal adaptive coping skills or developmental capacities fail to manage these situations effectively, some youth and adults resort to suicide as a means of managing intense overwhelming negative emotional states. This article has discussed suicide among older adults and children and adolescents. The role of the nurse in recognizing high-risk groups, analyzing assessment data, and implementing treatment interventions that integrate holistic concepts and reflect cultural sensitivity has been described. The ultimate goal of nurses working with the suicidal patient is prevention. Prevention of suicide requires an understanding of the emotional pain that precludes this act. Through preventive measures, the nurse has the opportunity to establish a therapeutic relationship that enhances adaptive coping skills, restores homeostasis of biologic process, and facilitates an optimal level of functioning in all age groups. PMID:12712675

Antai-Otong, Deborah

2003-03-01

238

[The effect of mithochondria targeted antioxidant SkQ1 on aging, life span and spontaneous carcinogenesis in three mice strains].  

PubMed

Female outbred SHR mice, inbred 129/Sv mice and transgenic HER-2/neu mice were given mitochondria targeted antioxidant SkQ1 with drinking water in the various doses (0,5-2500 nmol/kg day) since the age of 2 months, whereas control animals received tap water. Age-related dynamics of the body weight and temperature, the amount of drinking water and consumed food, estrous function, as well as parameters of the life span and spontaneous carcinogenesis were estimated. As compared with controls, no difference in the parameters of body weight and temperature or amount of consumed food and water in the treated mice of all studied mice strains was revealed. In SkQ1-treated SHR mice, the tendencies of inhibition of the age-dependent disturbances of estrous function and aging appearance were observed. No effect of SkQ1 on estrous function and external view in inbred and transgenic mice was shown. SkQ1 treatment significantly decreased locomotor activity (in 12-15 months old SHR and 129/Sv mice) and exercise tolerance in old (20 months) SHR mice. The treatment with SkQ1 (0,5-50 nmol/kg day) increased parameters of the life span in SHR mice (mean life span, mean life span of the last 10% of survival, median and maximum life span) without significant effect on the life span in 129/Sv and HER-2/neu mice. There was no reliable difference in tumor development in all SkQ1-treated mice strains as compared with the control. The drug considerably inhibited the incidence of age-associated non-tumor pathology in SHR mice. Our data suggest geroprotective activity of SkQ1, and a lack of toxic or carcinogenic activities during long term use. PMID:21137217

Iurova, M H; Zabezhinski?, M A; Piskunova, T S; Tyndyk, M L; Popovich, I G; anisimov, V N

2010-01-01

239

Reproduction, social behavior, and aging trajectories in honeybee workers.  

PubMed

While a negative correlation between reproduction and life span is commonly observed, specialized reproductive individuals outlive their non-reproductive nestmates in all eusocial species, including the honeybee, Apis mellifera (L). The consequences of reproduction for individual life expectancy can be studied directly by comparing reproductive and non-reproductive workers. We quantified the life span consequences of reproduction in honeybee workers by removal of the queen to trigger worker reproduction. Furthermore, we observed the social behavior of large cohorts of workers under experimental and control conditions to test for associations with individual life expectancy. Worker life expectancy was moderately increased by queen removal. Queenless colonies contained a few long-lived workers, and oviposition behavior was associated with a strong reduction in mortality risk, indicating that a reproductive role confers a significant survival advantage. This finding is further substantiated by an association between brood care behavior and worker longevity that depends on the social environment. In contrast, other in-hive activities, such as fanning, trophallaxis, and allogrooming did not consistently affect worker life expectancy. The influence of foraging varied among replicates. An earlier age of transitioning from in-hive tasks to outside foraging was always associated with shorter life spans, in accordance with previous studies. In sum, our studies quantify how individual mortality is affected by particular social roles and colony environments and demonstrate interactions between the two. The exceptional, positive association between reproduction and longevity in honeybees extends to within-caste plasticity, which may be exploited for mechanistic studies. PMID:23765046

Dixon, Luke; Kuster, Ryan; Rueppell, Olav

2014-02-01

240

Life history of flight morph females of Callosobruchus maculatus F.: evidence of a reproductive diapause.  

PubMed

Callosobruchus maculatus (F.) (Coleoptera : Bruchidae) is a tropical beetle that develops in the seeds of Vigna unguiculata. C. maculatus adults show an imaginal polymorphism with differences in morphological, behavioral and reproductive characteristics. Adults of the flight morph that emerge in cowpea storage systems were studied under natural climatic conditions. A large number of the flight morph females were in reproductive diapause and had a long imaginal life. These females did not synthesize vitellogenin, produced a specific diapause protein and possessed significant protein reserves. This suggests that the beetles survived in the tropical ecosystem for a long time and colonized the crops during the cowpea growing and flowering phases. Analysis of reproductive activity in females captured in the V. unguiculata crops indicates that they terminated their reproductive diapause and began to lay eggs as soon as the pods were formed. Few females of the flight morph were sexually active at the beginning of imaginal life. In this paper we discuss the adaptive significance of these two reproductive strategies in females of C. maculatus. PMID:12804717

Zannou, E T; Glitho, I A; Huignard, J; Monge, J P

2003-06-01

241

The olive constituent oleuropein exhibits proteasome stimulatory properties in vitro and confers life span extension of human embryonic fibroblasts.  

PubMed

Normal human fibroblasts undergo replicative senescence due to both genetic and environmental factors. Senescence and aging can be further accelerated by exposure of cells to a variety of oxidative agents that contribute among other effects to the accumulation of damaged proteins. The proteasome, a multicatalytic nonlysosomal protease, has impaired function during aging, while its increased expression delays senescence in human fibroblasts. The aim of this study was to identify natural compounds that enhance proteasome activity and exhibit antiaging properties. We demonstrate that oleuropein, the major constituent of Olea europea leaf extract, olive oil and olives, enhances the proteasome activities in vitro stronger than other known chemical activators, possibly through conformational changes of the proteasome. Moreover, continuous treatment of early passage human embryonic fibroblasts with oleuropein decreases the intracellular levels of reactive oxygen species (ROS), reduces the amount of oxidized proteins through increased proteasome-mediated degradation rates and retains proteasome function during replicative senescence. Importantly, oleuropein-treated cultures exhibit a delay in the appearance of senescence morphology and their life span is extended by approximately 15%. In summary, these data demonstrate the beneficial effect of oleuropein on human fibroblasts undergoing replicative senescence and provide new insights towards enhancement of cellular antioxidant mechanisms by natural compounds that can be easily up-taken through normal diet. PMID:17518699

Katsiki, Magda; Chondrogianni, Niki; Chinou, Ioanna; Rivett, A Jennifer; Gonos, Efstathios S

2007-06-01

242

A new life-span approach to conscientiousness and health: Combining the pieces of the causal puzzle.  

PubMed

Conscientiousness has been shown to predict healthy behaviors, healthy social relationships, and physical health and longevity. The causal links, however, are complex and not well elaborated. Many extant studies have used comparable measures for conscientiousness, and a systematic endeavor to build cross-study analyses for conscientiousness and health now seems feasible. Of particular interest are efforts to construct new, more comprehensive causal models by linking findings and combining data from existing studies of different cohorts. Although methodological perils can threaten such integration, such efforts offer an early opportunity to enliven a life course perspective on conscientiousness, to see whether component facets of conscientiousness remain related to each other and to relevant mediators across broad spans of time, and to bolster the findings of the few long-term longitudinal studies of the dynamics of personality and health. A promising approach to testing new models involves pooling data from extant studies as an efficient and heuristic prelude to large-scale testing of interventions. (PsycINFO Database Record (c) 2014 APA, all rights reserved). PMID:23088747

Friedman, Howard S; Kern, Margaret L; Hampson, Sarah E; Duckworth, Angela Lee

2014-05-01

243

A review of methionine dependency and the role of methionine restriction in cancer growth control and life-span extension.  

PubMed

Methionine is an essential amino acid with many key roles in mammalian metabolism such as protein synthesis, methylation of DNA and polyamine synthesis. Restriction of methionine may be an important strategy in cancer growth control particularly in cancers that exhibit dependence on methionine for survival and proliferation. Methionine dependence in cancer may be due to one or a combination of deletions, polymorphisms or alterations in expression of genes in the methionine de novo and salvage pathways. Cancer cells with these defects are unable to regenerate methionine via these pathways. Defects in the metabolism of folate may also contribute to the methionine dependence phenotype in cancer. Selective killing of methionine dependent cancer cells in co-culture with normal cells has been demonstrated using culture media deficient in methionine. Several animal studies utilizing a methionine restricted diet have reported inhibition of cancer growth and extension of a healthy life-span. In humans, vegan diets, which can be low in methionine, may prove to be a useful nutritional strategy in cancer growth control. The development of methioninase which depletes circulating levels of methionine may be another useful strategy in limiting cancer growth. The application of nutritional methionine restriction and methioninase in combination with chemotherapeutic regimens is the current focus of clinical studies. PMID:22342103

Cavuoto, Paul; Fenech, Michael F

2012-10-01

244

Effects of PPP1R1B (DARPP-32) Polymorphism on Feedback-Related Brain Potentials Across the Life Span  

PubMed Central

Maximizing gains during probabilistic reinforcement learning requires the updating of choice – outcome expectations at the time when the feedback about a specific choice or action is given. Extant theories and evidence suggest that dopaminergic modulation plays a crucial role in reinforcement learning and the updating of choice – outcome expectations. Furthermore, recently a positive component of the event-related potential about 200?ms (P2) after feedback has been suggested to reflect such updating. The efficacy of dopaminergic modulation changes across the life span. However, to date investigations of age-related differences in feedback-related P2 during reinforcement learning are still scarce. The present study thus aims to investigate whether individual differences in the feedback-related P2 would be associated with polymorphic variations in a dopamine relevant gene PPP1R1B (also known as DARPP-32) and whether the genetic effect may differ between age groups. We observed larger P2 amplitudes in individuals carrying the genotype associated with higher dopamine receptor efficacy, i.e., a allele homozygotes of a single nucleotide polymorphism (rs907094) of the PPP1R1B gene. Moreover, this effect was more pronounced in children and older adults in comparison to adolescents and younger adults. Together, our findings indicate that polymorphic variations in a dopamine relevant gene are associated with individual differences in brain-evoked potentials of outcome updating and hint at the possibility that genotype effects on neurocognitive phenotypes may vary as a function of brain maturation and aging.

Hammerer, Dorothea; Biele, Gudio; Muller, Viktor; Thiele, Holger; Nurnberg, Peter; Heekeren, Hauke R.; Li, Shu-Chen

2013-01-01

245

Caenorhabditis elegans DNA-2 helicase/endonuclease plays a vital role in maintaining genome stability, morphogenesis, and life span.  

PubMed

In eukaryotes, highly conserved Dna2 helicase/endonuclease proteins are involved in DNA replication, DNA double-strand break repair, telomere regulation, and mitochondrial function. The Dna2 protein assists Fen1 (Flap structure-specific endonuclease 1) protein in the maturation of Okazaki fragments. In yeast, Dna2 is absolutely essential for viability, whereas Fen1 is not. In Caenorhabditis elegans, however, CRN-1 (a Fen1 homolog) is essential, but Dna2 is not. Here we explored the biological function of C. elegans Dna2 (Cedna-2) in multiple developmental processes. We find that Cedna-2 contributes to embryonic viability, the morphogenesis of both late-stage embryos and male sensory rays, and normal life span. Our results support a model whereby CeDNA-2 minimizes genetic defects and maintains genome integrity during cell division and DNA replication. These finding may provide insight into the role of Dna2 in other multi-cellular organisms, including humans, and could have important implications for development and treatment of human conditions linked to the accumulation of genetic defects, such as cancer or aging. PMID:21414295

Lee, Myon-Hee; Hollis, Sarah E; Yoo, Bum Ho; Nykamp, Keith

2011-04-15

246

Tetrahydrocurcumin extends life span and inhibits the oxidative stress response by regulating the FOXO forkhead transcription factor  

PubMed Central

The O-type forkhead domain transcription factor (FOXO) is involved in many biological processes such as aging, the oxidative stress response, and growth regulation. FOXO activity is tightly controlled within cells. In particular, growth factor signaling pathways and the oxidative stress response can both stimulate nuclear translocation of this transcription factor. Here, we show that tetrahydrocurcumin (THC), a curcumin metabolite, regulates the oxidative stress response and aging via FOXO. In NIH3T3 cells, THC induced nuclear accumulation of FOXO4, a member of the FOXO family of transcription factors, by inhibiting phosphorylation of protein kinase B (PKB)/Akt. In Drosophila melanogaster, THC attenuated the oxidative stress response, an effect that was blocked in a foxo mutant background. THC also extended the life span of Drosophila under normal conditions, and loss of either foxo or Sir2 activity eliminated this effect. Based on these results, THC may regulate the aging process via an evolutionarily conserved signaling pathway that includes both foxo and Sir2.

Xiang, Lan; Nakamura, Yukiko; Lim, Young-Mi; Yamasaki, Yasutoyo; Kurokawa-Nose, Yumi; Maruyama, Wakako; Osawa, Toshihiko; Matsuura, Akira; Motoyama, Noboru; Tsuda, Leo

2011-01-01

247

The adaptive value of morphological, behavioural and life-history traits in reproductive female wolves.  

PubMed

Reproduction in social organisms is shaped by numerous morphological, behavioural and life-history traits such as body size, cooperative breeding and age of reproduction, respectively. Little is known, however, about the relative influence of these different types of traits on reproduction, particularly in the context of environmental conditions that determine their adaptive value. Here, we use 14 years of data from a long-term study of wolves (Canis lupus) in Yellowstone National Park, USA, to evaluate the relative effects of different traits and ecological factors on the reproductive performance (litter size and survival) of breeding females. At the individual level, litter size and survival improved with body mass and declined with age (c. 4-5 years). Grey-coloured females had more surviving pups than black females, which likely contributed to the maintenance of coat colour polymorphism in this system. The effect of pack size on reproductive performance was nonlinear as litter size peaked at eight wolves and then declined, and litter survival increased rapidly up to three wolves, beyond which it increased more gradually. At the population level, litter size and survival decreased with increasing wolf population size and canine distemper outbreaks. The relative influence of these different-level factors on wolf reproductive success followed individual > group > population. Body mass was the primary determinant of litter size, followed by pack size and population size. Body mass was also the main driver of litter survival, followed by pack size and disease. Reproductive gains because of larger body size and cooperative breeding may mitigate reproductive losses because of negative density dependence and disease. These findings highlight the adaptive value of large body size and sociality in promoting individual fitness in stochastic and competitive environments. PMID:23043440

Stahler, Daniel R; MacNulty, Daniel R; Wayne, Robert K; vonHoldt, Bridgett; Smith, Douglas W

2013-01-01

248

Care and the self: biotechnology, reproduction, and the good life  

PubMed Central

This paper explores a novel philosophy of ethical care in the face of burgeoning biomedical technologies. I respond to a serious challenge facing traditional bioethics with its roots in analytic philosophy. The hallmarks of these traditional approaches are reason and autonomy, founded on a belief in the liberal humanist subject. In recent years, however, there have been mounting challenges to this view of human subjectivity, emerging from poststructuralist critiques, such as Michel Foucault's, but increasingly also as a result of advances in biotechnology itself. In the face of these developments, I argue that the theoretical relevance and practical application of mainstream bioethics is increasingly under strain. Traditionalists will undoubtedly resist. Together, professional philosopher-bioethicists, public health policymakers, and the global commercial healthcare industry tend to respond conservatively by shoring up the liberal humanist subject as the foundation for medical ethics and consumer decision-making, appealing to the familiar tropes of reason, autonomy, and freedom. I argue for a different approach to bioethics, and work towards a new way to conceive of ethical relations in healthcare – one that does not presume a sovereign subject as the basis of dignity, personhood or democracy. Instead, I am critical of the narrow instantiations of reason, autonomy, and freedom, which, more recently, have been co-opted by a troubling neo-liberal politics of the self. Thus, I am critical of current trends in medical ethics, often running in tandem with corporate-governmental models of efficiency, accountability, and so-called evidence-based best practices. As an example of such market-driven conceptions of subjectivity, I discuss the paradigm of "self-care." Self-care shores up the traditional view of the self as a free agent. In this sense, self-care is looked upon favourably by mainstream bioethics in its focus on autonomy, while healthcare policy endorses this model for ideological and economic reasons. To contrast this, I propose a different model of care together with a different model of selfhood. Here I develop and apply Foucault's late work on the "care of the self." In this understanding of "care," I suggest that we might work towards an ethical self that is more commensurable both with recent theoretical views on subjectivity and – more pressingly – with the challenges of emergent biotechnologies. I end this paper with a discussion on ethical parenthood, which offers a practical reading of the "care of the self" in relation to new reproductive technologies (NRTs).

Murray, Stuart J

2007-01-01

249

Age Differences in Big Five Behavior Averages and Variabilities Across the Adult Life Span: Moving Beyond Retrospective, Global Summary Accounts of Personality  

Microsoft Academic Search

In 3 intensive cross-sectional studies, age differences in behavior averages and variabilities were examined. Three questions were posed: Does variability differ among age groups? Does the sizable variability in young adulthood persist throughout the life span? Do past conclusions about trait development, based on trait questionnaires, hold up when actual behavior is examined? Three groups participated: young adults (18–23 years),

Erik E. Noftle; William Fleeson

2010-01-01

250

Impaired insulin/IGF1 signaling extends life span by promoting mitochondrial L-proline catabolism to induce a transient ROS signal.  

PubMed

Impaired insulin and IGF-1 signaling (iIIS) in C. elegans daf-2 mutants extends life span more than 2-fold. Constitutively, iIIS increases mitochondrial activity and reduces reactive oxygen species (ROS) levels. By contrast, acute impairment of daf-2 in adult C. elegans reduces glucose uptake and transiently increases ROS. Consistent with the concept of mitohormesis, this ROS signal causes an adaptive response by inducing ROS defense enzymes (SOD, catalase), culminating in ultimately reduced ROS levels despite increased mitochondrial activity. Inhibition of this ROS signal by antioxidants reduces iIIS-mediated longevity by up to 60%. Induction of the ROS signal requires AAK-2 (AMPK), while PMK-1 (p38) and SKN-1 (NRF-2) are needed for the retrograde response. IIIS upregulates mitochondrial L-proline catabolism, and impairment of the latter impairs the life span-extending capacity of iIIS while L-proline supplementation extends C. elegans life span. Taken together, iIIS promotes L-proline metabolism to generate a ROS signal for the adaptive induction of endogenous stress defense to extend life span. PMID:22482728

Zarse, Kim; Schmeisser, Sebastian; Groth, Marco; Priebe, Steffen; Beuster, Gregor; Kuhlow, Doreen; Guthke, Reinhard; Platzer, Matthias; Kahn, C Ronald; Ristow, Michael

2012-04-01

251

The Primacy of Primary Control Is a Human Universal: A Reply to Gould's (1999) Critique of the Life-Span Theory of Control  

Microsoft Academic Search

This reply to S. J. Gould's (1999) critique of J. Heckhausen and R. Schulz's (1995) life-span theory of control addresses four issues: (1) the universal claim that primary control holds functional primacy over secondary control, (2) the status of secondary control as a confederate to primary control, (3) empirical evidence and paradigms for investigating universality and cultural variations, and (4)

Jutta Heckhausen; Richard Schulz

1999-01-01

252

Physical Attractiveness and Self-Esteem in Middle Childhood: Do Recent Life-Span Developmental Texts Perpetuate or Challenge Gender Stereotypes?  

ERIC Educational Resources Information Center

This document reports on an investigation focusing on how the content of introductory college psychology texts' content related to physical attractiveness and self-esteem. The primary objective of this study was to review how recently published life-span developmental texts present physical development in middle childhood as related to traditional…

Hensley, Beth H.

253

Evidence for a Relationship between Longevity of Mammalian Species and Life Spans of Normal Fibroblasts in vitro and Erythrocytes in vivo  

Microsoft Academic Search

The replicative life spans of mammalian fibroblasts in vitro were studied in a number of cell cultures representing eight species. Emphasis was placed on determining the population doubling level at which phase III (a period of decrease in the rate of proliferation) and chromosomal alterations occur. All the cell cultures studied went through a growth crisis, a period of apparent

Dan Rohme

1981-01-01

254

Evidence for a relationship between longevity of mammalian species and life spans of normal fibroblasts in vitro and erythrocytes in vivo  

PubMed Central

The replicative life spans of mammalian fibroblasts in vitro were studied in a number of cell cultures representing eight species. Emphasis was placed on determining the population doubling level at which phase III (a period of decrease in the rate of proliferation) and chromosomal alterations occur. All the cell cultures studied went through a growth crisis, a period of apparent growth cessation lasting for at least 2 weeks. In most cultures, the crisis represented the end of their replicative capacities, but in some cultures cell proliferation was resumed after the crisis. A predominantly diploid chromosome constitution (more than 75%) was demonstrated prior to the growth crisis. In cultures in which cell proliferation was resumed after the crisis, a nondiploid constitution prevailed in all cases except the rat (with 90% or more diploid cells all the time). The growth crisis occurred at population doubling levels that were characteristic for the species and was shown to be related to the species' maximal life span by a strict power law, being proportional to the square root of the maximal life span. Based on data in the literature, the same relationship was also valid for the lifespans of circulating mammalian erythrocytes in vivo. These results may indicate the prevalence of a common functional basis regulating the life span of fibroblasts and erythrocytes and thus operating in replicative as well as postmitotic cells in vitro and in vivo.

Rohme, Dan

1981-01-01

255

A cost-benefit analysis of acclimation to low irradiance in tropical rainforest tree seedlings: leaf life span and payback time for leaf deployment  

PubMed Central

The maintenance in the long run of a positive carbon balance under very low irradiance is a prerequisite for survival of tree seedlings below the canopy or in small gaps in a tropical rainforest. To provide a quantitative basis for this assumption, experiments were carried out to determine whether construction cost (CC) and payback time for leaves and support structures, as well as leaf life span (i) differ among species and (ii) display an irradiance-elicited plasticity. Experiments were also conducted to determine whether leaf life span correlates to CC and payback time and is close to the optimal longevity derived from an optimization model. Saplings from 13 tropical tree species were grown under three levels of irradiance. Specific-CC was computed, as well as CC scaled to leaf area at the metamer level. Photosynthesis was recorded over the leaf life span. Payback time was derived from CC and a simple photosynthesis model. Specific-CC displayed only little interspecific variability and irradiance-elicited plasticity, in contrast to CC scaled to leaf area. Leaf life span ranged from 4 months to >26 months among species, and was longest in seedlings grown under lowest irradiance. It was always much longer than payback time, even under the lowest irradiance. Leaves were shed when their photosynthesis had reached very low values, in contrast to what was predicted by an optimality model. The species ranking for the different traits was stable across irradiance treatments. The two pioneer species always displayed the smallest CC, leaf life span, and payback time. All species displayed a similar large irradiance-elicited plasticity.

Coste, Sabrina; Roggy, Jean-Christophe; Schimann, Heidy; Epron, Daniel; Dreyer, Erwin

2011-01-01

256

Radiation exposure and the risk of mortality from noncancer respiratory diseases in the life span study, 1950-2005.  

PubMed

An apparent association between radiation exposure and noncancer respiratory diseases (NCRD) in the Life Span Study (LSS) of atomic bomb survivors has been reported, but the biological validity of that observation is uncertain. This study investigated the possibility of radiation causation of noncancer respiratory diseases in detail by examining subtypes of noncancer respiratory diseases, temporal associations, and the potential for misdiagnosis and other confounding factors. A total of 5,515 NCRD diagnoses listed as the underlying cause of death on the death certificate were observed among the 86,611 LSS subjects with estimated weighted absorbed lung doses. Radiation dose-response analyses were conducted using Cox proportional hazard regression for pneumonia/influenza, other acute respiratory infections, chronic obstructive pulmonary disease and asthma. The linear excess relative risks (ERR) per gray (Gy) were 0.17 (95% CI 0.08, 0.27) for all NCRD and 0.20 (CI 0.09, 0.34) for pneumonia/influenza, which accounted for 63% of noncancer respiratory disease deaths. Adjustments for lifestyle and sociodemographic variations had almost no impact on the risk estimates. However, adjustments for indications of cancer and/or cardiovascular disease decreased the risk estimates, with ERR for total noncancer respiratory diseases declined by 35% from 0.17 to 0.11. Although it was impossible to fully adjust for the misdiagnosis of other diseases as noncancer respiratory diseases deaths in this study because of limitations of available data, nevertheless, the associations were reduced or eliminated by the adjustment that could be made. This helps demonstrates that the association between noncancer respiratory diseases and radiation exposure in previous reports could be in part be attributed to coincident cancer and/or cardiovascular diseases. PMID:24148011

Pham, Truong-Minh; Sakata, Ritsu; Grant, Eric J; Shimizu, Yukiko; Furukawa, Kyoji; Takahashi, Ikuno; Sugiyama, Hiromi; Kasagi, Fumiyoshi; Soda, Midori; Suyama, Akihiko; Shore, Roy E; Ozasa, Kotaro

2013-11-01

257

Deletion of Brca2 exon 27 causes hypersensitivity to DNA crosslinks, chromosomal instability, and reduced life span in mice  

NASA Technical Reports Server (NTRS)

The Brca2 tumor-suppressor gene contributes to genomic stability, at least in part by a role in homologous recombinational repair. BRCA2 protein is presumed to function in homologous recombination through interactions with RAD51. Both exons 11 and 27 of Brca2 code for domains that interact with RAD51; exon 11 encodes eight BRC motifs, whereas exon 27 encodes a single, distinct interaction domain. Deletion of all RAD51-interacting domains causes embryonic lethality in mice. A less severe phenotype is seen with BRAC2 truncations that preserve some, but not all, of the BRC motifs. These mice can survive beyond weaning, but are runted and infertile, and die very young from cancer. Cells from such mice show hypersensitivity to some genotoxic agents and chromosomal instability. Here, we have analyzed mice and cells with a deletion of only the RAD51-interacting region encoded by exon 27. Mice homozygous for this mutation (called brca2(lex1)) have a shorter life span than that of control littermates, possibly because of early onsets of cancer and sepsis. No other phenotype was observed in these animals; therefore, the brca2(lex1) mutation is less severe than truncations that delete some BRC motifs. However, at the cellular level, the brca2(lex1) mutation causes reduced viability, hypersensitivity to the DNA interstrand crosslinking agent mitomycin C, and gross chromosomal instability, much like more severe truncations. Thus, the extreme carboxy-terminal region encoded by exon 27 is important for BRCA2 function, probably because it is required for a fully functional interaction between BRCA2 and RAD51. Copyright 2003 Wiley-Liss, Inc.

Donoho, Greg; Brenneman, Mark A.; Cui, Tracy X.; Donoviel, Dorit; Vogel, Hannes; Goodwin, Edwin H.; Chen, David J.; Hasty, Paul

2003-01-01

258

Evaluation of platelet thromboxane radioimmunoassay method to measure platelet life-span: Comparison with /sup 111/indium-platelet method  

SciTech Connect

The platelet activation during radiolabeling in vitro with Cr-51 and In-111 may affect the platelet life-span (PLS) in vivo. A new RIA method to measure PLS is being evaluated. Aspirin inhibits platelet thromboxane (TxA/sub 2/) by acetylating cyclooxygenase. The time required for the TxA/sub 2/ levels to return towards control values depends on the rate of new platelets entering circulation and is a measure of PLS. A single dose of aspirin (150mg) was given to 5 normal human subjects. Blood samples were collected for 2 days before aspirin and daily for 10 days. TxA/sub 2/ production in response to endogenous thrombin was studied by allowing 1 ml blood sample to clot at 37/sup 0/C for 90 min. Serum TxB/sub 2/ (stable breakdown product of Tx-A/sub 2/) levels determined by RIA technique. The plot of TxB/sub 2/ levels (% control) against time showed a gradual increase. The PLS calculated by linear regression analysis assuming a 2-day lag period before cyclooxygenase recovery is 9.7 +- 2.37. In the same 5 subjects, platelets from a 50ml blood sample were labeled with /sup 111/In-tropolone in 2 ml autologous plasma. Starting at 1 hr after injection of labeled platelets, 10 blood samples were obtained over a 8 day period. The PLS calculated based on a linear regression analysis is 10.2 +. 1.4. The PLS measured from the rate of platelet disappearance from circulation and the rate of platelet regeneration into circulation are quite comparable in normal subjects. TxA/sub 2/ regeneration RIA may provide a method to measure PLS without administering radioactivity to patient.

Vallabhajosula, S.; Machac, J.; Badimon, L.; Lipszyc, H.; Goldsmith, S.J.; Fuster, V.

1985-05-01

259

Environmental Contingency in Life History Strategies: The Influence of Mortality and Socioeconomic Status on Reproductive Timing  

PubMed Central

Why do some people have children early, whereas others delay reproduction? By considering the trade-offs between using one’s resources for reproduction versus other tasks, the evolutionary framework of life history theory predicts that reproductive timing should be influenced by mortality and resource scarcity. A series of experiments examined how mortality cues influenced the desire to have children sooner rather than later. The effects of mortality depended critically on whether people grew up in a relatively resource-scarce or resource-plentiful environment. For individuals growing up relatively poor, mortality cues produced a desire to reproduce sooner—to want children now, even at the cost of furthering one’s education or career. Conversely, for individuals growing up relatively wealthy, mortality cues produced a desire to delay reproduction—to further one’s education or career before starting a family. Overall, mortality cues appear to shift individuals into different life history strategies as a function of childhood socioeconomic status, suggesting important implications for how environmental factors can influence fertility and family size.

Griskevicius, Vladas; Delton, Andrew W.; Robertson, Theresa E.; Tybur, Joshua M.

2013-01-01

260

Lifetime reproductive effort.  

PubMed

In a 1966 American Naturalist article, G. C. Williams initiated the study of reproductive effort (RE) with the prediction that longer-lived organisms ought to expend less in reproduction per unit of time. We can multiply RE, often measured in fractions of adult body mass committed to reproduction per unit time, by the average adult life span to get lifetime reproductive effort (LRE). Williams's hypothesis (across species, RE decreases as life span increases) can then be refined to read "LRE will be approximately constant for similar organisms." Here we show that LRE is a key component of fitness in nongrowing populations, and thus its value is central to understanding life-history evolution. We then develop metabolic life-history theory to predict that LRE ought to be approximately 1.4 across organisms despite extreme differences in production and growth rates. We estimate LRE for mammals and lizards that differ in growth and production by five- to tenfold. The distributions are approximately normal with means of 1.43 and 1.41 for lizards and mammals, respectively (95% confidence intervals: 1.3-1.5 and 1.2-1.6). Ultimately, therefore, a female can only produce a mass of offspring approximately equal to 1.4 times her own body mass during the course of her life. PMID:18171160

Charnov, Eric L; Warne, Robin; Moses, Melanie

2007-12-01

261

The reproductive cycle and life history of the Arctic copepod Calanus glacialis in the White Sea  

Microsoft Academic Search

Seasonal variations in the gonad development and sex ratio of copepodite stage V (CV) and adults were examined from February\\u000a to November in order to understand the reproductive cycle and the life history of Calanus glacialis in the White Sea. Gonad maturation, sexual differentiation and moulting to adults take place during the 2nd year of development.\\u000a Energy accumulation takes place

K. N. Kosobokova

1999-01-01

262

Positive Regulation of DNA Double Strand Break Repair Activity during Differentiation of Long Life Span Cells: The Example of Adipogenesis  

PubMed Central

Little information is available on the ability of terminally differentiated cells to efficiently repair DNA double strand breaks (DSBs), and one might reasonably speculate that efficient DNA repair of these threatening DNA lesions, is needed in cells of long life span with no or limited regeneration from precursor. Few tissues are available besides neurons that allow the study of DNA DSBs repair activity in very long-lived cells. Adipocytes represent a suitable model since it is generally admitted that there is a very slow turnover of adipocytes in adult. Using both Pulse Field Gel Electrophoresis (PFGE) and the disappearance of the phosphorylated form of the histone variant H2AX, we demonstrated that the ability to repair DSBs is increased during adipocyte differentiation using the murine pre-adipocyte cell line, 3T3F442A. In mammalian cells, DSBs are mainly repaired by the non-homologous end-joining pathway (NHEJ) that relies on the DNA dependent protein kinase (DNA-PK) activity. During the first 24 h following the commitment into adipogenesis, we show an increase in the expression and activity of the catalytic sub-unit of the DNA-PK complex, DNA-PKcs. The increased in DNA DSBs repair activity observed in adipocytes was due to the increase in DNA-PK activity as shown by the use of DNA-PK inhibitor or sub-clones of 3T3F442A deficient in DNA-PKcs using long term RNA interference. Interestingly, the up-regulation of DNA-PK does not regulate the differentiation program itself. Finally, similar positive regulation of DNA-PKcs expression and activity was observed during differentiation of primary culture of pre-adipocytes isolated from human sub-cutaneous adipose tissue. Our results show that DNA DSBs repair activity is up regulated during the early commitment into adipogenesis due to an up-regulation of DNA-PK expression and activity. In opposition to the general view that DNA DSBs repair is decreased during differentiation, our results demonstrate that an up-regulation of this process might be observed in post-mitotic long-lived cells.

Meulle, Aline; Salles, Bernard; Daviaud, Daniele; Valet, Philippe; Muller, Catherine

2008-01-01

263

Sleep Apnea, Reproductive Hormones and Quality of Sexual Life in Severely Obese Men  

PubMed Central

The effect of sleep apnea on the reproductive function of obese men is not entirely elucidated. The objective of this study was to define the effect of sleep apnea on the reproductive hormones and sexual function in obese men. This study included 89 severely obese men with BMI ?35 kg/m2 considering gastric bypass surgery. Anthropometrics (weight, and BMI), reproductive hormones, and sleep studies were measured. The sexual quality of life was assessed using the Impact of Weight on Quality of Life-Lite questionnaire (IWQOL-Lite). The mean age of our patients was 46.9 ± 11.0 years, the mean BMI was 47.8 ± 8.7 kg/m2 and the mean weight was 337.7 ± 62.4 lb. After correction for age and BMI, means of free testosterone per severity group of sleep apnea were as follows: no or mild sleep apnea 74.4 ± 3.8 pg/ml, moderate sleep apnea 68.6 ± 4.2 pg/ml, and severe sleep apnea 60.2 ± 2.92 pg/ml, P = 0.014. All other parameters of sleep apnea including hypopnea index, percent time below a SpO2 of 90%, and percent time below a SpO2 of 80% were also negatively correlated with testosterone levels after correction for age and BMI. BMI and presence of coronary artery disease decreased the sexual quality of life. Sleep apnea was associated with reduced sexual quality of life. In summary, sleep apnea negatively affects testosterone levels independent of BMI. Severely obese men had decreased sexual quality of life.

Hammoud, Ahmad O.; Walker, James M.; Gibson, Mark; Cloward, Tom V.; Hunt, Steven C.; Kolotkin, Ronette L.; Adams, Ted D.; Meikle, A. Wayne

2013-01-01

264

Cooperative effect of antisense-Rb and antisense-p53 oligomers on the extension of life span in human diploid fibroblasts, TIG-1.  

PubMed

Normal human diploid fibroblasts, TIG-1, which have a replicative life span of about 62 population doublings (PD), tended to senesce after about 50 PD with a gradual decrease in sensitivity to serum. Treatment of TIG-1 cells with the antisense-Rb oligomer, which completely depleted the retinoblastoma susceptibility gene product (RB), extended life span by about 10 PD. Treatment with the antisense-p53 oligomer alone had no effect; however, cotreatment with the antisense-Rb oligomer further potentiated the extension and the increased sensitivity to serum caused by the antisense-Rb oligomer alone, suggesting that p53 and RB function in separate, yet complementary pathways in signal transduction to senescence. The c-fos expression, which is presumed to be regulated negatively by RB, was not stimulated in partially senescent TIG-1 cells by treatment with the antisense-Rb oligomer. PMID:1909121

Hara, E; Tsurui, H; Shinozaki, A; Nakada, S; Oda, K

1991-08-30

265

Older Motherhood and the Changing Life Course in the Era of Assisted Reproductive Technologies  

PubMed Central

Midlife, once a focus of particular interest to gerontologists because of its implications for later life, has recently received little attention. But as new reproductive technologies have expanded in the United States, motherhood is occurring at older ages. While older motherhood is not a new social practice, what is unique is that an increasing number of women are becoming pregnant through technological means, often for the first time, at the end of their reproductive cycle. These women can be understood as part of a new middle age, engaging in new life course possibilities that respond to changing social, cultural, physical, and economic realities, and potentially extending much later in the life course. Drawing on interviews with 79 couples, we utilize symbolic interactionist conceptualizations of identity and stigma to consider how women negotiate the shifting social identities associated with older motherhood. We conclude that older motherhood will be one phenomenon contributing to an enduring change in views of what constitutes old age, and that it will be seen as occurring much later in the life course.

Friese, Carrie; Becker, Gay; Nachtigall, Robert D.

2008-01-01

266

Differential Longitudinal Changes in Cortical Thickness, Surface Area and Volume across the Adult Life Span: Regions of Accelerating and Decelerating Change.  

PubMed

Human cortical thickness and surface area are genetically independent, emerge through different neurobiological events during development, and are sensitive to different clinical conditions. However, the relationship between changes in the two over time is unknown. Additionally, longitudinal studies have almost invariably been restricted to older adults, precluding the delineation of adult life span trajectories of change in cortical structure. In this longitudinal study, we investigated changes in cortical thickness, surface area, and volume after an average interval of 3.6 years in 207 well screened healthy adults aged 23-87 years. We hypothesized that the relationships among metrics are dynamic across the life span, that the primary contributor to cortical volume reductions in aging is cortical thinning, and that magnitude of change varies with age and region. Changes over time were seen in cortical area (mean annual percentage change [APC], -0.19), thickness (APC, -0.35), and volume (APC, -0.51) in most regions. Volume changes were primarily explained by changes in thickness rather than area. A negative relationship between change in thickness and surface area was found across several regions, where more thinning was associated with less decrease in area, and vice versa. Accelerating changes with increasing age was seen in temporal and occipital cortices. In contrast, decelerating changes were seen in prefrontal and anterior cingulate cortices. In conclusion, a dynamic relationship between cortical thickness and surface area changes exists throughout the adult life span. The mixture of accelerating and decelerating changes further demonstrates the importance of studying these metrics across the entire adult life span. PMID:24948804

Storsve, Andreas B; Fjell, Anders M; Tamnes, Christian K; Westlye, Lars T; Overbye, Knut; Aasland, Hilde W; Walhovd, Kristine B

2014-06-18

267

SIRT6LinksHistoneH3Lysine9Deacetylation to NF-kB-Dependent Gene Expression and Organismal Life Span  

Microsoft Academic Search

SUMMARY Members of the sirtuin (SIRT) family of NAD-depen- dent deacetylases promote longevity in multiple organisms. Deficiency of mammalian SIRT6 leads to shortened life span and an aging-like phenotype in mice, but the underlying molecular mechanisms are unclear. Here we show that SIRT6 functions at chro- matin to attenuate NF-kB signaling. SIRT6 interacts with the NF-kB RELA subunit and deacetylates

Tiara L. A. Kawahara; Eriko Michishita; Adam S. Adler; Mara Damian; Elisabeth Berber; Meihong Lin; Ron A. McCord; Kristine C. L. Ongaigui; Lisa D. Boxer; Howard Y. Chang; Katrin F. Chua

268

Life-span studies in rats exposed to [sup 239]PuO[sub 2] aerosol II. Nonpulmonary tumor formation in control and exposed groups  

Microsoft Academic Search

Female young adult, SPF, Wistar rats, obtained from the same supplier over an 18-month period, were examined in a life-span study with inhaled [sup 239]PuO[sub 2]. Nonpulmonary tumors were evaluated both in 1,052 rats comprising 16 control groups and in 2,105 exposed rats. Tumors in the pituitary gland, mammary glands, uterus, and thyroid glands, in order of decreasing prevalence, accounted

2009-01-01

269

Relationships of leaf dark respiration to leaf nitrogen, specific leaf area and leaf life-span: a test across biomes and functional groups  

Microsoft Academic Search

Based on prior evidence of coordinated multiple leaf trait scaling, we hypothesized that variation among species in leaf\\u000a dark respiration rate (R\\u000a d) should scale with variation in traits such as leaf nitrogen (N), leaf life-span, specific leaf area (SLA), and net photosynthetic\\u000a capacity (A\\u000a max). However, it is not known whether such scaling, if it exists, is similar among

Peter B. Reich; Michael B. Walters; David S. Ellsworth; James M. Vose; John C. Volin; Charles GreshamWilliam; William D. Bowman

1998-01-01

270

Loss of Ubp3 increases silencing, decreases unequal recombination in rDNA, and shortens the replicative life span in Saccharomyces cerevisiae.  

PubMed

Ubp3 is a conserved ubiquitin protease that acts as an antisilencing factor in MAT and telomeric regions. Here we show that ubp3? mutants also display increased silencing in ribosomal DNA (rDNA). Consistent with this, RNA polymerase II occupancy is lower in cells lacking Ubp3 than in wild-type cells in all heterochromatic regions. Moreover, in a ubp3? mutant, unequal recombination in rDNA is highly suppressed. We present genetic evidence that this effect on rDNA recombination, but not silencing, is entirely dependent on the silencing factor Sir2. Further, ubp3? sir2? mutants age prematurely at the same rate as sir2? mutants. Thus our data suggest that recombination negatively influences replicative life span more so than silencing. However, in ubp3? mutants, recombination is not a prerequisite for aging, since cells lacking Ubp3 have a shorter life span than isogenic wild-type cells. We discuss the data in view of different models on how silencing and unequal recombination affect replicative life span and the role of Ubp3 in these processes. PMID:24760971

Oling, David; Masoom, Rehan; Kvint, Kristian

2014-06-15

271

Effects of radiation and lifestyle factors on risks of urothelial carcinoma in the Life Span Study of atomic bomb survivors.  

PubMed

Among the Life Span Study (LSS) of Atomic-bomb survivors, recent estimates showed that unspecified bladder cancer had high radiation sensitivity with a notably high female-to-male excess relative risk (ERR) per radiation dose ratio and were the only sites for which the ERR did not decrease with attained age. These findings, however, did not consider lifestyle factors, which could potentially confound or modify the risk estimates. This study estimated the radiation risks of the most prevalent subtype of urinary tract cancer, urothelial carcinoma, while accounting for smoking, consumption of fruit, vegetables, alcohol and level of education (a surrogate for socioeconomic status). Eligible study subjects included 105,402 (males = 42,890) LSS members who were cancer-free in 1958 and had estimated radiation doses. Members were censored due to loss of follow-up, incident cancer of another type, death, or the end of calendar year 2001. Surveys (by mail or clinical interview) gathered lifestyle data periodically for 1963-1991. There were 63,827 participants in one or more survey. Five hundred seventy-three incident urothelial carcinoma cases occurred, of which 364 occurred after lifestyle information was available. Analyses were performed using Poisson regression methods. The excess relative risk per weighted gray unit (the gamma component plus 10 times the neutron component, Gy(w)) was 1.00 (95% CI: 0.43-1.78) but the risks were not dependent upon age at exposure or attained age. Lifestyle factors other than smoking were not associated with urothelial carcinoma risk. Neither the magnitude of the radiation ERR estimate (1.00 compared to 0.96), nor the female-to-male (F:M) ERR/Gy(w) ratio (3.2 compared to 3.4) were greatly changed after accounting for all lifestyle factors. A multiplicative model of gender-specific radiation and smoking effects was the most revealing though there was no evidence of significant departures from either the additive or multiplicative joint effect models. Among the LSS cohort members with doses greater than 0.005 Gy(w) (average dose 0.21 Gy(w)), the attributable fraction of urothelial carcinoma due to radiation was 7.1% in males and 19.7% in females. Among current smokers, the attributable fraction of urothelial carcinoma due to smoking was 61% in males and 52% in females. Relative risk estimates of smoking risk were approximately two for smokers compared to nonsmokers. After adjustment for lifestyle factors, gender-specific radiation risks and the F:M ERR/Gy(w), the ratios of excess urothelial carcinoma risk were similar to the estimates without adjusting for lifestyle factors. Smoking was the primary factor responsible for excess urothelial carcinoma in this cohort. These findings led us to conclude that the radiation risk estimates of urothelial carcinoma do not appear to be strongly confounded or modified by smoking, consumption of alcohol, fruits, or vegetables, or level of education. PMID:22631857

Grant, E J; Ozasa, K; Preston, D L; Suyama, A; Shimizu, Y; Sakata, R; Sugiyama, H; Pham, T-M; Cologne, J; Yamada, M; De Roos, A J; Kopecky, K J; Porter, M P; Seixas, N; Davis, S

2012-07-01

272

Reproductive health and quality of life of young Burmese refugees in Thailand  

PubMed Central

Background Of the 140 000 Burmese* refugees living in camps in Thailand, 30% are youths aged 15-24. Health services in these camps do not specifically target young people and their problems and needs are poorly understood. This study aimed to assess their reproductive health issues and quality of life, and identifies appropriate service needs. Methods We used a stratified two-stage random sample questionnaire survey of 397 young people 15-24 years from 5,183 households, and 19 semi-structured qualitative interviews to assess and explore health and quality of life issues. Results The young people in the camps had very limited knowledge of reproductive health issues; only about one in five correctly answered at least one question on reproductive health. They were clear that they wanted more reproductive health education and services, to be provided by health workers rather than parents or teachers who were not able to give them the information they needed. Marital status was associated with sexual health knowledge; having relevant knowledge of reproductive health was up to six times higher in married compared to unmarried youth, after adjusting for socio-economic and demographic factors. Although condom use was considered important, in practice a large proportion of respondents felt too embarrassed to use them. There was a contradiction between moral views and actual behaviour; more than half believed they should remain virgins until marriage, while over half of the youth experienced sex before marriage. Two thirds of women were married before the age of 18, but two third felt they did not marry at the right age. Forced sex was considered acceptable by one in three youth. The youth considered their quality of life to be poor and limited due to confinement in the camps, the limited work opportunities, the aid dependency, the unclear future and the boredom and unhappiness they face. Conclusions The long conflict in Myanmar and the resultant long stay in refugee camps over decades affect the wellbeing of these young people. Lack of sexual health education and relevant services, and their concerns for their future are particular problems, which need to be addressed. Issues of education, vocational training and job possibilities also need to be considered. *Burmese is used for all ethnic groups

2010-01-01

273

Use of a Modified Reproductive Life Plan to Improve Awareness of Preconception Health in Women with Chronic Disease  

PubMed Central

Objective: Chronic diseases such as hypertension, diabetes, and obesity pose unique reproductive challenges for women. Preconception health results in improved reproductive outcomes. We designed an interventional study testing the use of a reproductive life plan to improve knowledge of preconception and contraception health in women with chronic diseases. Methods: Primarily underserved, English-and Spanish-speaking women aged 18 to 40 years with active diabetes, hypertension, or obesity were recruited. We developed a revised reproductive life plan specific to these diseases. Two resident physicians performed reproductive plan counseling. Pre- and postcounseling surveys were administered to evaluate knowledge and attitudes about chronic disease and the effects on a potential pregnancy. Results: Twenty-seven women (average age = 31 years) were surveyed. Of the subjects, 85.2% were obese, 29.6% had hypertension, and 7.4% had diabetes. Significant increases were reported in understanding risks of pregnancy associated with diabetes (p < 0.001), hypertension (p < 0.001), and obesity (p < 0.01). After counseling, women increased their knowledge about a reproductive plan (p < 0.001) and increased support and information to make reproductive health choices (p = 0.001 and p < 0.01, respectively). The largest improvements in postcounseling variables occurred in women with the lowest precounseling test scores and in women without children. Conclusion: A reproductive life plan is a brief, cost-effective preconception and contraception counseling tool in the primary care setting for women with chronic diseases. This tool increases knowledge about reproductive health and enables women with chronic diseases to make informed decisions about their reproductive future.

Mittal, Pooja; Dandekar, Aparna; Hessler, Danielle

2014-01-01

274

Reproductive functions of kisspeptin and Gpr54 across the life cycle of mice and men  

PubMed Central

The reproductive phenotypes of nearly two dozen patients with mutations in GPR54 have been reported, as have the phenotypes of four mouse lines mutant for Gpr54 and two lines mutant for Kiss1. These phenotypes demonstrate that kisspeptin/Gpr54 function is required at all phases of the life cycle when the secretion of gonadotropin-releasing hormone (GnRH) is robust. Furthermore, there is phenotypic variability ranging from severe hypogonadism to partial sexual development. Collectively, these findings suggest that kisspeptin and Gpr54 serve as an essential conduit for relaying developmental information to the GnRH neuron.

Broder-Fingert, Sarabeth; Seminara, Stephanie B.

2009-01-01

275

Much more than a gene: hereditary breast and ovarian cancer, reproductive choices and family life.  

PubMed

This article presents the results of a study that investigates the way in which carriers of a mutation on the BRCA1 or the BRCA2 gene, associated with a high risk of breast and ovarian cancer, make their reproductive decisions. Using semi-structured interviews, the study explored the way in which these persons reflected on the acceptability of taking the risk of transmitting this mutation to the next generation, the arguments they used in favor or against taking that risk, and in the light of these arguments, their opinion on the acceptability of preimplantation genetic diagnosis (PGD) as a reproductive option. The findings suggest that when carriers are planning to have a(nother) child, they are mainly concerned by the risk of transmitting 'much more than a gene': essentially painful experiences not only with respect to health, such as undergoing cancer surveillance or combatting one's own illness, but also with regards to family life, such as witnessing the illness and death of a close relative, encountering difficulties in finding a partner or reconsidering one's plans to have a family. As for opinions concerning the acceptability of PGD as a reproductive option, opinions about personal recourse were varied but all expressed the understanding that PGD should be made available to those persons who consider it their best option. PMID:22048863

Dekeuwer, Catherine; Bateman, Simone

2013-05-01

276

Introducing reproductive life plan-based information in contraceptive counselling: an RCT  

PubMed Central

STUDY QUESTION Can reproductive life plan (RLP)-based information in contraceptive counselling before pregnancy increase women's knowledge of reproduction, and of the importance of folic acid intake in particular? SUMMARY ANSWER The RLP-based information increased women's knowledge of reproduction including knowledge of folic acid intake. WHAT IS KNOWN ALREADY Many women have insufficient knowledge of reproduction, including a health-promoting lifestyle prior to conception, and highly educated women in particular postpone childbearing until an age when their fertile capacity has started to decrease. STUDY DESIGN, SIZE, DURATION The study was an randomized controlled trial with one intervention group (IG) and two control groups (CG1, CG2). A sample size calculation indicated that 82 women per group would be adequate. Recruitment took place during 3 months in 2012 and 299 women were included. The women were randomized in blocks of three. All groups received standard care (contraceptive counselling, Chlamydia testing, cervical screening). In addition, women in the IG were given oral and written RLP-based information about reproduction. PARTICIPANTS/MATERIALS, SETTING, METHODS A total of 299 out of 338 (88%) Swedish-speaking women visiting a Student Health Centre were included (mean age 23 years); response rate was 88%. Before the counselling, women in the IG and the CG1 completed a baseline questionnaire, including questions about lifestyle changes in connection to pregnancy planning, family planning intentions and knowledge of reproduction (e.g. the fecundity of an ovum). At follow-up 2 months after inclusion, a structured telephone interview was performed in all groups (n = 262, 88% participation rate). MAIN RESULTS AND THE ROLE OF CHANCE There was no difference between the groups regarding the mean knowledge score at baseline. The IG scored higher at follow-up than at baseline (P < 0.001); the mean increased from 6.4 to 9.0 out of a maximum 20 points. The women in the CG1 scored no differently at follow-up than at baseline. The difference in the knowledge score between the IG and the two CGs was significant (P < 0.001), whereas no difference was shown between the two CGs. There was no difference between the groups at baseline regarding how many women could mention folic acid intake among the things to do when planning to get pregnant. At follow-up, 22% in the IG, 3% in CG1 and 1% in CG2 mentioned folic acid intake (P < 0.001). At follow-up, more women in the IG also wished to have their last child earlier in life (P < 0.001) than at baseline, while there was no difference in the CG1. LIMITATIONS, REASONS FOR CAUTION As the study sample consisted of university students, it is possible that the effect of the intervention was connected to a high level of education and conclusions for all women of reproductive age should be drawn with caution. WIDER IMPLICATIONS OF THE FINDINGS The provision of RLP-based information seems to be a feasible tool for promoting reproductive health. STUDY FUNDING/COMPETING INTEREST(S) Study funding was received from the Faculty of Medicine, Uppsala University, Sweden. There are no conflicts of interest. TRIAL REGISTRATION NUMBER ClinicalTrial.gov Identifier NCT01739101.

Stern, J.; Larsson, M.; Kristiansson, P.; Tyden, T.

2013-01-01

277

Free Radical Production, Antioxidant Capacity, and Oxidative Stress Response Signatures in Fibroblasts From Lewis Dwarf Rats: Effects of Life Span-Extending Peripubertal GH Treatment  

PubMed Central

The discovery that in invertebrates, disruption of the insulin/insulin-like growth factor (IGF)-1 pathway extends life span and increases resistance to oxidative injury led to the hypothesis that IGF-1 signaling may play a role in regulating cellular reactive oxygen species production, oxidative stress resistance, and consequentially, organismal life span in mammals. However, previous studies testing this hypothesis in rodent models of IGF-1 deficiency yielded controversial results. The Lewis dwarf rat is a useful model of human growth hormone (GH)/IGF-1 deficiency as it mimics many of the pathophysiological alterations present in human GH/IGF-1–deficient patients as well as elderly individuals. Peripubertal treatment of Lewis dwarf rats with GH results in a significant extension of life span. The present study was designed to test the role of the GH/IGF-1 axis in regulating cellular oxidative stress and oxidative stress resistance, utilizing primary fibroblasts derived from control rats, Lewis dwarf rats and GH-replete dwarf rats. Measurements of cellular dihydroethidium and C-H2DCFDA fluorescence showed that cellular O2·? and peroxide production were similar in each group. Fibroblasts from control and Lewis dwarf rats exhibited similar antioxidant capacities and comparable sensitivity to H2O2, rotenone, high glucose, tunicamycin, thapsigargin, paraquat, and mitomycin, which cause apoptosis through increasing oxidative stress, mitochondrial damage, ATP depletion, and/or by damaging DNA, lipids and proteins. Fibroblasts from GH-replete rats exhibited significantly increased antioxidant capacities and superior resistance to H2O2, rotenone and bacterial lipopolysaccharide–induced cell death compared with cells from Lewis dwarf rats, whereas their sensitivity to the other stressors investigated was not statistically different. Thus, low circulating IGF-1 levels present in vivo in Lewis dwarf rats do not elicit long-lasting alterations in cellular reactive oxygen species generation and oxidative stress resistance, whereas life span–extending peripubertal GH treatment resulted in increased antioxidant capacity and increased resistance to cellular injury caused by some, but not all, oxidative stressors.

Sosnowska, Danuta; Podlutsky, Andrej; Koncz, Peter; Sonntag, William E.

2011-01-01

278

Flashbulb Memories and Posttraumatic Stress Reactions Across the Life-Span: Age-related effects of the German Occupation of Denmark during WWII  

PubMed Central

A representative sample of older Danes were interviewed about experiences from the German occupation of Denmark in WWII. The number of participants with flashbulb memories for the German invasion (1940) and capitulation (1945) increased with participants’ age at the time of the events up to age 8. Among participants under 8 years at the time of their most traumatic event, age at the time correlated positively with current level of posttraumatic stress reactions, vividness of stressful memories and their centrality to life-story and identity. These findings were replicated in Study 2 for self-nominated stressful events sampled from the entire life span using a representative sample of Danes born after 1945. The results are discussed in relation to Posttraumatic Stress Disorder (PTSD) and childhood amnesia.

Berntsen, Dorthe; Rubin, David C.

2014-01-01

279

Extracts of Cistanche deserticola Can Antagonize Immunosenescence and Extend Life Span in Senescence-Accelerated Mouse Prone 8 (SAM-P8) Mice  

PubMed Central

The senescence accelerated mouse prone 8 substrain (SAM-P8), widely accepted as an animal model for studying aging and antiaging drugs, was used to examine the effects of dietary supplementation with extracts of Cistanche deserticola (ECD) which has been used extensively in traditional Chinese medicine because of its perceived ability to promote immune function in the elderly. Eight-month-old male SAM-P8 mice were treated with ECD by daily oral administrations for 4 weeks. The results showed that dietary supplementation of 150?mg/kg and 450?mg/kg of ECD could extend the life span measured by Kaplan-Meier survival analysis in dose-dependent manner. Dietary supplementation of SAM-P8 mice for 4 weeks with 100, 500, and 2500?mg/kg of ECD was shown to result in significant increases in both naive T and natural killer cells in blood and spleen cell populations. In contrast, peripheral memory T cells and proinflammatory cytokine, IL-6 in serum, were substantially decreased in the mice that ingested 100 and 500?mg/kg of ECD daily. Additionally, Sca-1 positive cells, the recognized progenitors of peripheral naive T cells, were restored in parallel. Our results provide clear experimental support for long standing clinical observational studies showing that Cistanche deserticola possesses significant effects in extending life span and suggest this is achieved by antagonizing immunosenescence.

Zhang, Ke; Ma, Xu; He, Wenjun; Li, Haixia; Han, Shuyan; Jiang, Yong; Wu, Hounan; Han, Li; Uotsu, Nobuo; Yamaguchi, Kohji; Ma, Zhizhong; Tu, Pengfei

2014-01-01

280

Dmp53, basket and drICE gene knockdown and polyphenol gallic acid increase life span and locomotor activity in a Drosophila Parkinson's disease model  

PubMed Central

Understanding the mechanism(s) by which dopaminergic (DAergic) neurons are eroded in Parkinson’s disease (PD) is critical for effective therapeutic strategies. By using the binary tyrosine hydroxylase (TH)-Gal4/UAS-X RNAi Drosophila melanogaster system, we report that Dmp53, basket and drICE gene knockdown in dopaminergic neurons prolong life span (p < 0.05; log-rank test) and locomotor activity (p < 0.05; ?2 test) in D. melanogaster lines chronically exposed to (1 mM) paraquat (PQ, oxidative stress (OS) generator) compared to untreated transgenic fly lines. Likewise, knockdown flies displayed higher climbing performance than control flies. Amazingly, gallic acid (GA) significantly protected DAergic neurons, ameliorated life span, and climbing abilities in knockdown fly lines treated with PQ compared to flies treated with PQ only. Therefore, silencing specific gene(s) involved in neuronal death might constitute an excellent tool to study the response of DAergic neurons to OS stimuli. We propose that a therapy with antioxidants and selectively “switching off” death genes in DAergic neurons could provide a means for pre-clinical PD individuals to significantly ameliorate their disease condition.

Ortega-Arellano, Hector Flavio; Jimenez-Del-Rio, Marlene; Velez-Pardo, Carlos

2013-01-01

281

Autophagy proteins LC3B, ATG5 and ATG12 participate in quality control after mitochondrial damage and influence life span  

PubMed Central

Mitochondrial health is maintained by the quality control mechanisms of mitochondrial dynamics (fission and fusion) and mitophagy. Decline of these processes is thought to contribute to aging and neurodegenerative diseases. To investigate the role of mitochondrial quality control in aging on the cellular level, human umbilical vein endothelial cells (HUVEC) were subjected to mitochondria-targeted damage by combining staining of mitochondria and irradiation. This treatment induced a short boost of reactive oxygen species, which resulted in transient fragmentation of mitochondria followed by mitophagy, while mitochondrial dynamics were impaired. Furthermore, targeted mitochondrial damage upregulated autophagy factors LC3B, ATG5 and ATG12. Consequently these proteins were overexpressed in HUVEC as an in vitro aging model, which significantly enhanced the replicative life span up to 150% and the number of population doublings up to 200%, whereas overexpression of LAMP-1 did not alter the life span. Overexpression of LC3B, ATG5 and ATG12 resulted in an improved mitochondrial membrane potential, enhanced ATP production and generated anti-apoptotic effects, while ROS levels remained unchanged and the amount of oxidized proteins increased. Taken together, these data relate LC3B, ATG5 and ATG12 to mitochondrial quality control after oxidative damage, and to cellular longevity.

Mai, Soren; Muster, Britta; Bereiter-Hahn, Jurgen

2012-01-01

282

On the Life History of Planktonic Foraminifera: Lunar Reproduction Cycle in Globigerinoides Sacculifer (Brady)  

NASA Astrophysics Data System (ADS)

Detailed plankton sampling in the Gulf of Elat, Red Sea, demonstrates a lunar periodicity in the abundance of the foraminifer Globigerinoides sacculifer in surface water as well as below the photic zone. Shell size distribution coupled with abundance changes and laboratory observations suggests the following scheme for the life cycle of this spinose foraminifer: Young individuals of roughly 200 µm (average diameter) are found in surface water 7-8 days after the full moon. During the course of 1 week they grow rapidly to an average size of 300-400 µm. The larger and mature individuals, many of which having a saclike chamber, start to sink down below the photic zone. They add a final chamber, shed their spines, thicken their shell, continue to sink well within the main thermocline, digest their symbionts, and eventually reproduce via gametogenesis at the full moon. We do not have information about the fusion of the gametes, the embryonic growth stages, and the vertical migration of the young foraminifera. However, 1 week after the full moon, small individuals appear again in surface waters and the cycle repeats itself. Although the mechanism by which the moon is synchronizing the reproduction cycle is not clear, it obviously offers better chances for the gametes to fuse. Sinking to deeper water may provide the following advantages: avoidance of predators at the crucial stage of their life cycle when they are without their spine protection; synchronization of reproduction by triggering gametogenesis due to the change from light/dark cycle to complete darkness; better chances for the gametes to concentrate and fuse on a narrow sigma-t surface at the zone where the pycnocline is steeper; and finally, better chances for survival for the young unprotected foraminifera who start their growth in an environment that contains fewer potential predators.

Erez, Jonathan; Almogi-Labin, Ahuva; Avraham, Sophie

1991-06-01

283

The Study of Life Review. An Approach to the Investigation of Intellectual Development across the Life Span. Studien und Berichte 47.  

ERIC Educational Resources Information Center

A study looked for age differences in the quality of responses to the Life Review Task (LRT), studied the LRT itself as a tool for exploring wisdom and intellectual functioning in adulthood, and considered personality characteristics and life experience as alternative predictors of response quality. Sixty-three West German women of different ages…

Staudinger, Ursula M.

284

Investigation of a free-tip rotor configuration for research on spanwise life distributions and wake velocity surveys of a semi-span wing with a discontinuous twist  

NASA Technical Reports Server (NTRS)

A wind tunnel test was conducted in the NASA Ames 7 x 10 Foot Wind Tunnel to investigate the lift distribution on a semi-span wing with a discontinuous change in spanwise twist. The semi-span wing had a tip with an adjustable pitch angle independent on the inboard section pitch angle simulating the free-tip rotor blade when its free-tip is at a deflected position. The spanwise lift distribution over the wing and the tip were measured and three component velocity surveys behind the wing were obtained with a three dimensional laser Doppler velocimeter (LV) with the wing at one angle of attack and the tip deflected at different pitch angles. A six component internal strain gage balance was also used to measure total forces and moments on the tip. The three dimensional lift was computed from the two dimensional life distributions obtained from the LV and from the strain gage balance. The results from both experimental methods are shown to be in agreement with predictions made by a steady, three dimensional panel code, VSAERO.

Fortin, Paul; Kumagai, Hiroyuki

1989-01-01

285

Effects of exygen-nitrogen (1:1) at 760 Torr on the life span and fine structure of Drosophila melanogaster.  

PubMed

Exposure of Drosophila melanogaster adult males to an atmosphere of O2-N2 (1:1) at 760 Torr resulted in a marked reduction of life span. Among the fine structural changes occurring in the oxygen-poisoned flies, the following were similar to age-related changes: ceroid-lipofuscin accumulation in the visceral organs, sponginess of the brain and accumulation of lamellated dense bodies in the nerve cells. Also, the oxygen-poisoned flies showed a loss of the cytoplasmic membranes of the sperm cells, an alteration which was previously found in y-irradiated, but not in normal senescent, flies. In our opinion, oxygen poisoning of Drosophila may provide a valid model of accelerated aging, at least in regard to peroxidation injury of cell organelles and ceroid-lipofuscin accumulation. PMID:806750

Miquel, J; Lundgren, P R; Bensch, K G

1975-01-01

286

The life span of silicone gel breast implants and a comparison of mammography, ultrasonography, and magnetic resonance imaging in detecting implant rupture: a meta-analysis.  

PubMed

Because of the growing concern surrounding the integrity and life span of silicone gel breast implants and the reported variations in the diagnostic accuracy of various imaging techniques in identifying ruptured implants, the authors undertook a meta-analysis of articles in the scientific literature to examine these concerns. They were able to include reports from the literature that detailed the condition and removal of 1,099 breast implants during the past 7 years. The median life span of a silicone gel implant was estimated to be 16.4 years. Of the implants, 79.1% were intact at 10 years, falling to 48.7% by 15 years. The sensitivities and specificities of three imaging modalities used in the diagnosis of implant rupture (mammography, ultrasonography, and magnetic resonance imaging [MRI]) were also evaluated and compared statistically in an effort to discover which of the three techniques might serve as the most reliable screening tool in the diagnosis of gel implant rupture. The sensitivity of mammography for finding a ruptured implant is 28.4% with a specificity of 92.9%. Ultrasonography has a sensitivity and specificity of 59.0% and 76.8% respectively compared with MRI, which was 78.1% and 80.0% respectively. For implants in place for 10 years, one would need to image 3.3 implants by ultrasound to identify a single possible rupture. However, because of the 76.8% specificity, 8.1 implants would need to be imaged to find a confirmed intraoperative rupture. This was similar to MRI, in which 3.1 implants would need to be imaged to detect one suspected rupture, and 6.1 implants would need to be imaged to find one intraoperatively confirmed rupture. The authors do not recommend either ultrasound or MRI as a screening tool based on their meta-analysis. PMID:9869129

Goodman, C M; Cohen, V; Thornby, J; Netscher, D

1998-12-01

287

Continuity of genetic and environmental influences on cognition across the life span: A meta-analysis of longitudinal twin and adoption studies.  

PubMed

The longitudinal rank-order stability of cognitive ability increases dramatically over the life span. Theoretical perspectives differ in their emphasis on genetic mechanisms in explaining the longitudinal stability of cognition and how stability changes with development. However, the patterns of stability of genetic and environmental influences on cognition over the life span remain poorly understood. We searched for longitudinal studies of cognition that reported raw genetically informative longitudinal correlations or parameter estimates from longitudinal behavior genetic models. We identified 150 combinations of time points and measures from 15 independent longitudinal samples. In total, longitudinal data came from 4,548 monozygotic twin pairs raised together, 7,777 dizygotic twin pairs raised together, 34 monozygotic twin pairs raised apart, 78 dizygotic twin pairs raised apart, 141 adoptive sibling pairs, and 143 nonadoptive sibling pairs, ranging in age from infancy through late adulthood. At all ages, cross-time genetic correlations and shared environmental correlations were substantially larger than cross-time nonshared environmental correlations. Cross-time correlations for genetic and shared environmental components were, respectively, low and moderate during early childhood, increased sharply over child development, and remained high from adolescence through late adulthood. Cross-time correlations for nonshared environmental components were low across childhood and gradually increased to moderate magnitudes in adulthood. Increasing phenotypic stability over child development was almost entirely mediated by genetic factors. Time-based decay of genetic and shared environmental stability was more pronounced earlier in child development. Results are interpreted in reference to theories of gene-environment correlation and interaction. (PsycINFO Database Record (c) 2014 APA, all rights reserved). PMID:24611582

Tucker-Drob, Elliot M; Briley, Daniel A

2014-07-01

288

Relevance of NAC-2, an Na+-coupled citrate transporter, to life span, body size and fat content in Caenorhabditis elegans.  

PubMed Central

We have cloned and functionally characterized an Na+-coupled citrate transporter from Caenorhabditis elegans (ceNAC-2). This transporter shows significant sequence homology to Drosophila Indy and the mammalian Na+-coupled citrate transporter NaCT (now known as NaC2). When heterologously expressed in a mammalian cell line or in Xenopus oocytes, the cloned ceNAC-2 mediates the Na+-coupled transport of various intermediates of the citric acid cycle. However, it transports the tricarboxylate citrate more efficiently than dicarboxylates such as succinate, a feature different from that of ceNAC-1 (formerly known as ceNaDC1) and ceNAC-3 (formerly known as ceNaDC2). The transport process is electrogenic, as evidenced from the substrate-induced inward currents in oocytes expressing the transporter under voltage-clamp conditions. Expression studies using a reporter-gene fusion method in transgenic C. elegans show that the gene is expressed in the intestinal tract, the organ responsible for not only the digestion and absorption of nutrients but also for the storage of energy in this organism. Functional knockdown of the transporter by RNAi (RNA interference) not only leads to a significant increase in life span, but also causes a significant decrease in body size and fat content. The substrates of ceNAC-2 play a critical role in metabolic energy production and in the biosynthesis of cholesterol and fatty acids. The present studies suggest that the knockdown of these metabolic functions by RNAi is linked to an extension of life span and a decrease in fat content and body size.

Fei, You-Jun; Liu, Jin-Cai; Inoue, Katsuhisa; Zhuang, Lina; Miyake, Katsuya; Miyauchi, Seiji; Ganapathy, Vadivel

2004-01-01

289

Increased production of mitochondrial reactive oxygen species and reduced adult life span in an insecticide-resistant strain of Anopheles gambiae.  

PubMed

Control of the malaria vector An. gambiae is still largely obtained through chemical intervention using pyrethroids, such as permethrin. However, strains of An. gambiae that are resistant to the toxic effects of pyrethroids have become widespread in several endemic areas over the last decade. The objective of this study was to assess differences in five life-history traits (larval developmental time and the body weight, fecundity, hatch rate, and longevity of adult females) and energy metabolism between a strain of An. gambiae that is resistant to permethrin (RSP), due to knockdown resistance and enhanced metabolic detoxification, and a permethrin susceptible strain reared under laboratory conditions. We also quantified the expression levels of five antioxidant enzyme genes: GSTe3, CAT, GPXH1, SOD1, and SOD2. We found that the RSP strain had a longer developmental time than the susceptible strain. Additionally, RSP adult females had higher wet body weight and increased water and glycogen levels. Compared to permethrin susceptible females, RSP females displayed reduced metabolic rate and mitochondrial coupling efficiency and higher mitochondrial ROS production. Furthermore, despite higher levels of GSTe3 and CAT transcripts, RSP females had a shorter adult life span than susceptible females. Collectively, these results suggest that permethrin resistance alleles might affect energy metabolism, oxidative stress, and adult survival of An. gambiae. However, because the strains used in this study differ in their genetic backgrounds, the results need to be interpreted with caution and replicated in other strains to have significant implications for malaria transmission and vector control. PMID:24555527

Otali, D; Novak, R J; Wan, W; Bu, S; Moellering, D R; De Luca, M

2014-06-01

290

Increased production of mitochondrial reactive oxygen species and reduced adult life span in an insecticide-resistant strain of Anopheles gambiae  

PubMed Central

Control of the malaria vector An. gambiae is still largely obtained through chemical intervention using pyrethroids, such as permethrin. However, strains of An. gambiae that are resistant to the toxic effects of pyrethroids have become widespread in several endemic areas over the last decade. The objective of this study was to assess differences in five life-history traits (larval developmental time and the body weight, fecundity, hatch rate, and longevity of adult females) and energy metabolism between a strain of An. gambiae that is resistant to permethrin (RSP), due to knockdown resistance and enhanced metabolic detoxification, and a permethrin susceptible strain reared under laboratory conditions. We also quantified the expression levels of five antioxidant enzyme genes: GSTe3, CAT, GPXH1, SOD1, and SOD2. We found that the RSP strain had a longer developmental time than the susceptible strain. Additionally, RSP adult females had higher wet body weight and increased water and glycogen levels. Compared to permethrin susceptible females, RSP females displayed reduced metabolic rate and mitochondrial coupling efficiency and higher mitochondrial ROS production. Furthermore, despite higher levels of GSTe3 and CAT transcripts, RSP females had a shorter adult life span than susceptible females. Collectively, these results suggest that permethrin resistance alleles might affect energy metabolism, oxidative stress, and adult survival of An. gambiae. However, because the strains used in this study differ in their genetic backgrounds, the results need to be interpreted with caution and replicated in other strains in order to have significant implications for malaria transmission and vector control.

Otali, Dennis; Novak, Robert J.; Wan, Wen; Bu, Su; Moellering, Douglas R.; De Luca, Maria

2014-01-01

291

Towards a general life-history model of the superorganism: predicting the survival, growth and reproduction of ant societies  

PubMed Central

Social insect societies dominate many terrestrial ecosystems across the planet. Colony members cooperate to capture and use resources to maximize survival and reproduction. Yet, when compared with solitary organisms, we understand relatively little about the factors responsible for differences in the rates of survival, growth and reproduction among colonies. To explain these differences, we present a mathematical model that predicts these three rates for ant colonies based on the body sizes and metabolic rates of colony members. Specifically, the model predicts that smaller colonies tend to use more energy per gram of biomass, live faster and die younger. Model predictions are supported with data from whole colonies for a diversity of species, with much of the variation in colony-level life history explained based on physiological traits of individual ants. The theory and data presented here provide a first step towards a more general theory of colony life history that applies across species and environments.

Shik, Jonathan Z.; Hou, Chen; Kay, Adam; Kaspari, Michael; Gillooly, James F.

2012-01-01

292

Life span in online communities  

NASA Astrophysics Data System (ADS)

Recently online communities have attracted great interest and have become an important medium of information exchange between users. The aim of this work is to introduce a simple model of the evolution of online communities. This model describes (a) the time evolution of users’ activity in a web service, e.g., the time evolution of the number of online friends or written posts, (b) the time evolution of the degree distribution of a social network, and (c) the time evolution of the number of active users of a web service. In the second part of the paper we investigate the influence of the users’ lifespan (i.e., the total time in which they are active in an online community) on the process of rumor propagation in evolving social networks. Viral marketing is an important application of such method of information propagation.

Grabowski, A.; Kosi?ski, R. A.

2010-12-01

293

Reproduction, survival, and life table parameters of the predatory mite Cheyletus malaccensis (Acari: Cheyletidae) at various constant temperatures  

Microsoft Academic Search

Reproduction, survival, and life table parameters of the predatory mite Cheyletus malaccensis Oudemans were evaluated at six constant temperatures: 17.5, 20, 25, 30, 32.5 and 35°C, feeding on Tyrophagus putrescentiae (Schrank). Preoviposition period of fertilized and virgin females varied with temperature from ca. 9 days at 17.5°C to ca.\\u000a 1.5 day at 32.5°C and then increased to ca. 3 days at 35°C. Virgin

Nickolas E. PalyvosNickolas; Nickolas G. Emmanouel

2011-01-01

294

Telomeres and human reproduction  

PubMed Central

Telomeres mediate biologic aging in organisms as diverse as plants, yeast, and mammals. We propose a telomere theory of reproductive aging that posits telomere shortening in the female germ line as the primary driver of reproductive aging in women. Experimental shortening of telomeres in mice, which normally do not exhibit appreciable oocyte aging, and which have exceptionally long telomeres, recapitulates the aging phenotype of human oocytes. Telomere shortening in mice reduces synapsis and chiasmata, increases embryo fragmentation, cell cycle arrest, apoptosis, spindle dysmorphologies, and chromosome abnormalities. Telomeres are shorter in the oocytes from women undergoing in vitro fertilization, who then produce fragmented, aneuploid embryos that fail to implant. In contrast, the testes are replete with spermatogonia that can rejuvenate telomere reserves throughout the life of the man by expressing telomerase. Differences in telomere dynamics across the life span of men and women may have evolved because of the difference in the inherent risks of aging on reproduction between men and women. Additionally, growing evidence links altered telomere biology to endometriosis and gynecologic cancers, thus future studies should examine the role of telomeres in pathologies of the reproductive tract.

Kalmbach, Keri Horan; Antunes, Danielle Mota Fontes; Dracxler, Roberta Caetano; Knier, Taylor Warner; Seth-Smith, Michelle Louise; Wang, Fang; Liu, Lin; Keefe, David Lawrence

2013-01-01

295

Changes in gas exchange characteristics during the life span of giant sequoia: implications for response to current and future concentrations of atmospheric ozone.  

PubMed

Native stands of giant sequoia (Sequoiadendron giganteum Bucholz) are being exposed to relatively high concentrations of atmospheric ozone produced in urban and agricultural areas upwind. The expected change in environmental conditions over the next 100 years is likely to be unprecedented in the life span (about 2,500 years) of giant sequoia. We determined changes in physiological responses of three age classes of giant sequoia (current-year, 12-, and 125-year-old) to differing concentrations of ozone, and assessed age-related differences in sensitivity to pollutants by examining physiological changes (gas exchange, water use efficiency) across the life span of giant sequoia (current-year, 2-, 5-, 20-, 125-, and > 2,000-year-old trees). The CO(2) exchange rate (CER) was greater in current-year (12.1 micro mol CO(2) m(-2) s(-1)) and 2-year-old seedlings (4.8 micro mol CO(2) m(-2) s(-1)) than in all older trees (3.0 micro mol CO(2) m(-2) s(-1), averaged across the four older age classes). Dark respiration was highest for current-year seedlings (-6.5 +/- 0.7 micro mol CO(2) m(-2) s(-1)) and was increased twofold in symptomatic individuals exposed to elevated ozone concentrations. Stomatal conductance (g(s)) was greater in current-year (355 mmol H(2)O m(-2) s(-1)) and 2-year-old seedlings (200 mmol H(2)O m(-2) s(-1)) than in all older trees (50 mmol H(2)O m(-2) s(-1)), indicating that the ozone concentration in substomatal cavities is higher in young seedlings than in trees. Significant changes in water use efficiency, as indicated by C(i)/C(a), occurred in trees between ages 5 and 20 years. We conclude that giant sequoias seedlings are sensitive to atmospheric ozone until they are about 5 years old. Low conductance, high water use efficiency, and compact mesophyll all contribute to a natural ozone tolerance, or defense, or both, in foliage of older trees. PMID:14967638

Grulke, N. E.; Miller, P. R.

1994-01-01

296

The control processes and subjective well-being of Chinese teachers: evidence of convergence with and divergence from the key propositions of the motivational theory of life-span development  

PubMed Central

An analytical review of the motivational theory of life-span development reveals that this theory has undergone a series of elegant theoretical integrations. Its claim to universality nonetheless brings forth unresolved controversies. With the purpose of scrutinizing the key propositions of this theory, an empirical study was designed to examine the control processes and subjective well-being of Chinese teachers (N = 637). The OPS-Scales (Optimization in Primary and Secondary Control Scales) for the Domain of Teaching were constructed to assess patterns of control processes. Three facets of subjective well-being were investigated with the Positive and Negative Affect Schedule, the Life Satisfaction Scale, and the Subjective Vitality Scale. The results revealed certain aspects of alignment with and certain divergences from the key propositions of the motivational theory of life-span development. Neither “primacy of primary control” nor “primacy of secondary control” was clearly supported. Notably, using different criteria for subjective well-being yielded different subtypes of primary and secondary control as predictors. The hypothesized life-span trajectories of primary and secondary control received limited support. To advance the theory in this area, we recommend incorporating Lakatos' ideas about sophisticated falsification by specifying the hard core of the motivational theory of life-span development and articulating new auxiliary hypotheses.

Wong, Wan-chi; Li, Yin; Sun, Xiaoyan; Xu, Huanu

2014-01-01

297

Early Life Exposure to Endocrine-Disrupting Chemicals Causes Lifelong Molecular Reprogramming of the Hypothalamus and Premature Reproductive Aging  

PubMed Central

Gestational exposure to the estrogenic endocrine disruptor methoxychlor (MXC) disrupts the female reproductive system at the molecular, physiological, and behavioral levels in adulthood. The current study addressed whether perinatal exposure to endocrine disruptors reprograms expression of a suite of genes expressed in the hypothalamus that control reproductive function and related these molecular changes to premature reproductive aging. Fischer rats were exposed daily for 12 consecutive days to vehicle (dimethylsulfoxide), estradiol benzoate (EB) (1 mg/kg), and MXC (low dose, 20 ?g/kg or high dose, 100 mg/kg), beginning on embryonic d 19 through postnatal d 7. The perinatally exposed females were aged to 16–17 months and monitored for reproductive senescence. After euthanasia, hypothalamic regions [preoptic area (POA) and medial basal hypothalamus] were dissected for real-time PCR of gene expression or pyrosequencing to assess DNA methylation of the Esr1 gene. Using a 48-gene PCR platform, two genes (Kiss1 and Esr1) were significantly different in the POA of endocrine-disrupting chemical-exposed rats compared with vehicle-exposed rats after Bonferroni correction. Fifteen POA genes were up-regulated by at least 50% in EB or high-dose MXC compared with vehicle. To understand the epigenetic basis of the increased Esr1 gene expression, we performed bisulfite conversion and pyrosequencing of the Esr1 promoter. EB-treated rats had significantly higher percentage of methylation at three CpG sites in the Esr1 promoter compared with control rats. Together with these molecular effects, perinatal MXC and EB altered estrous cyclicity and advanced reproductive senescence. Thus, early life exposure to endocrine disruptors has lifelong effects on neuroendocrine gene expression and DNA methylation, together with causing the advancement of reproductive senescence.

Walker, Deena M.; Zama, Aparna M.; Armenti, AnnMarie E.; Uzumcu, Mehmet

2011-01-01

298

Impairment of Quality of Life in Symptomatic Reproductive Tract Infection and Sexually Transmitted Infection  

PubMed Central

Background Reproductive tract infections (RTI) and sexually transmitted infections (STI) are often subclinical and remain undetected. The current study aimed to estimate the burden of RTI/STI, associated symptoms, risk factors and the impact of the condition on quality of life (QOL). Methods A community based, cross sectional study was conducted. Married women aged 18 to 49 years were selected through systematic random sampling in a rural area. A semi-structured questionnaire was used to evaluate socio-demographic characteristics, symptoms, risk factors and knowledge regarding RTI/STI. A standardized instrument from the World Health Organization (WHO-BREF) was used to measure QOL. The chi square (?2) and unpaired t tests were used for statistic evaluation of results. Results In a sample of 464 women, 60 (13%) women were symptomatic and the commonest symptom was abnormal vaginal discharge (n = 54). 24 of the women had sought treatment. Age (p = 0.0006) and socio-economic status (p = 0.0004) were significant for an outcome of RTI/STI. Significant risk factors included lack of use of barrier contraceptives (p < 0.001), past history of infection (p < 0.001), use of reusable cloth during menstruation (p < 0.001) and presence of spousal symptoms (p < 0.001). QOL scores were impacted on all domains with significant differences. The largest mean difference was in the social relations and sexual activity domain. Conclusion In the current study, the obtained data was a 13% prevalence of RTI/ STI symptoms with a significant lack of awareness regarding occurrence and prevention among women and significant impairment on all QOL domains.

Valsangkar, Sameer; Selvaraju, Dhamodharan; Rameswarapu, Rohin; Kamutapu, Shivaprasad

2014-01-01

299

Life-span studies in rats exposed to 239PuO2 aerosol. II. Nonpulmonary tumor formation in control and exposed groups.  

PubMed

Female young adult, SPF, Wistar rats, obtained from the same supplier over an 18-month period, were examined in a life-span study with inhaled 239PuO2. Nonpulmonary tumors were evaluated both in 1052 rats comprising 16 controls groups and in 2105 exposed rats. Tumors in the pituitary gland, mammary glands, uterus, and thyroid glands, in order of decreasing prevalence, accounted for 90% of all tumors. Uterine tumors comprised 55% of all nonpulmonary malignant tumors. A substantial variability in tumor incidence was seen in most organs and for most tumor types among the 16 cohort subgroups, which was not explained by husbandry conditions or mortality patterns. The incidence of thyroid tumors ranged from 0 to 21% and uterine tumors from 14 to 45% among control cohorts. Pulmonary metastases were seen in 12% of all rats irrespective of treatment, two thirds of which were uterine adenocarcinomas that appeared histologically similar to some primary lung adenocarcinomas. A tumor incidence of about 1.5% was associated with metal identification ear tags. Except in the lung, no significant difference was found in tumor location or type between control and exposed rats. A twofold or greater increase in tumors in exposed rats was found in Zymbal gland, bladder, brain, and liver; tumor incidence in each organ was < 1%. PMID:1464807

Sanders, C L

1992-01-01

300

Rho Kinase Inhibitor Y-27632 Prolongs the Life Span of Adult Human Keratinocytes, Enhances Skin Equivalent Development, and Facilitates Lentiviral Transduction  

PubMed Central

The use of tissue-engineered human skin equivalents (HSE) for fundamental research and industrial application requires the expansion of keratinocytes from a limited number of skin biopsies donated by adult healthy volunteers or patients. A pharmacological inhibitor of Rho-associated protein kinases, Y-27632, was recently reported to immortalize neonatal human foreskin keratinocytes. Here, we investigated the potential use of Y-27632 to expand human adult keratinocytes and evaluated its effects on HSE development and in vitro gene delivery assays. Y-27632 was found to significantly increase the life span of human adult keratinocytes (up to five to eight passages). The epidermal morphology of HSEs generated from high-passage, Y-27632-treated keratinocytes resembled the native epidermis and was improved by supplementing Y-27632 during the submerged phase of HSE development. In addition, Y-27632-treated keratinocytes responded normally to inflammatory stimuli, and could be used to generate HSEs with a psoriatic phenotype, upon stimulation with relevant cytokines. Furthermore, Y-27632 significantly enhanced both lentiviral transduction efficiency of primary adult keratinocytes and epidermal morphology of HSEs generated thereof. Our study indicates that Y-27632 is a potentially powerful tool that is used for a variety of applications of adult human keratinocytes.

Rodijk-Olthuis, Diana; Jansen, Patrick A.M.; van Vlijmen-Willems, Ivonne M.J.J.; van Erp, Piet E.; Joosten, Irma; Zeeuwen, Patrick L.J.M.

2012-01-01

301

Tackling Vision-Related Disability in Old Age: An Application of the Life-Span Theory of Control to Narrative Data  

PubMed Central

This study used the life-span theory of control (Heckhausen, J., & Schulz, R.) to examine adaptation to disability in old age. A narrative approach to data collection was used to assess the strategies employed by 364 older adults with macular degeneration to deal with daily challenges. Findings revealed a rich array of strategies. Compensatory Primary Control was reported by nearly all respondents, Compensatory Secondary Control by a majority, and Selective Primary Control by half of the participants. Selective Secondary Control was the least reported. Differences in strategy use depending on level of vision impairment were the most pronounced within the category of Compensatory Primary Control for strategies that involved using help from others and alternative means. Within the category of Selective Secondary Control, effort to maintain a positive outlook was associated with higher impairment levels, whereas within the category of Compensatory Secondary Control, attempts not to dwell on problems related to vision were associated with lower impairment levels. Implications for conceptual development and future research are discussed.

Brennan, Mark; Horowitz, Amy; Reinhardt, Joann P.

2010-01-01

302

Life history plasticity after attaining a dietary threshold for reproduction is associated with protein storage in flesh flies  

PubMed Central

Summary Body condition affects the timing and magnitude of life history transitions. Therefore, identifying proximate mechanisms involved in assessing condition is critical to understanding how these mechanisms affect the expression of life history plasticity. Nutrient storage is an important body condition parameter, likely playing roles in both attaining minimum body-condition thresholds for life history transitions and expression of life history traits. We manipulated protein availability for females of the flesh fly Sarcophaga crassipalpis to determine whether reproductive timing and output would remain plastic or become fixed. Liver was provided for 0, 2, 4, or 6 days of adult pre-reproductive development. Significantly, liver was removed after the feeding threshold had been attained and females had committed to producing a clutch. We also identified the major storage proteins and monitored their abundances, because protein stores may serve as an index of body condition and therefore may play an important role in life history transitions and plasticity. Flesh flies showed clear post-threshold plasticity in reproductive timing. Females fed protein for 2 days took ~30% longer to provision their clutch than those fed for 4 or 6 days. Observations of oogenesis showed the 2-day group expressed a different developmental program including slower egg provisioning. Protein availability also affected reproductive output. Females fed protein for 2 days produced ~20% fewer eggs than females fed 4 or 6 days. Six-day treated females provisioned larger eggs than 4-day treated females, followed by 2-day treated females with the smallest eggs. Two storage proteins were identified, LSP-1 and LSP-2. LSP-2 accumulation differed across feeding treatments. The 2- and 4-day treatment groups accumulated LSP-2 stores but depleted them during provisioning of the first clutch, whereas the 6-day group accumulated the greatest quantity of LSP-2 and had substantial LSP-2 stores remaining at the end of the clutch. This pattern of accumulation and depletion suggests that LSP-2 could play roles in both provisioning the current clutch and future clutches, making it a good candidate molecule for affecting reproductive timing and allotment. LSP-1 was not associated with post-threshold plasticity; it was carried over from larval feeding into adulthood and depleted uniformly across all feeding groups.

Hahn, Daniel A.; James, Laura N.; Milne, Kathy R.; Hatle, John D.

2009-01-01

303

The role of disturbance in the evolution of life history strategies in the intertidal mussels Mytilus edulis and Mytilus californianus  

Microsoft Academic Search

The intertidal mussels Mytilus edulis and M. californianus compete for space on the west coast of North America. An analysis of differences in size, growth rate, age at first reproduction, life span, mode of reproduction, niche and habitats between these two species demonstrates that their life history strategies are different in several important ways. M. californianus is a larger, sturdier,

Thomas H. Suchanek

1981-01-01

304

Reproduction and Early Life History of the Redfin Pickerel, (Esox americanus americanus).  

National Technical Information Service (NTIS)

The reproductive strategy of the redf in pickerel (Esox americanus americanus) in a blackwater system in Sumter County, South Carolina was studied using daily aging techniques derived from otolith analysis. The presence of biannual spawning, a significant...

M. S. Ballek

1994-01-01

305

Combination of hTERT and bmi-1, E6, or E7 Induces Prolongation of the Life Span of Bone Marrow Stromal Cells from an Elderly Donor without Affecting Their Neurogenic Potential†  

PubMed Central

Murine bone marrow stromal cells differentiate not only into mesodermal derivatives, such as osteocytes, chondrocytes, adipocytes, skeletal myocytes, and cardiomyocytes, but also into neuroectodermal cells in vitro. Human bone marrow stromal cells are easy to isolate but difficult to study because of their limited life span. To overcome this problem, we attempted to prolong the life span of bone marrow stromal cells and investigated whether bone marrow stromal cells modified with bmi-1, hTERT, E6, and E7 retained their differentiated capability, or multipotency. In this study, we demonstrated that the life span of bone marrow stromal cells derived from a 91-year-old donor could be extended and that the stromal cells with an extended life span differentiated into neuronal cells in vitro. We examined the neuronally differentiated cells morphologically, physiologically, and biologically and compared the gene profiles of undifferentiated and differentiated cells. The neuronally differentiated cells exhibited characteristics similar to those of midbrain neuronal progenitors. Thus, the results of this study support the possible use of autologous-cell graft systems to treat central nervous system diseases in geriatric patients.

Mori, Taisuke; Kiyono, Tohru; Imabayashi, Hideaki; Takeda, Yukiji; Tsuchiya, Kohei; Miyoshi, Shunichirou; Makino, Hatsune; Matsumoto, Kenji; Saito, Hirohisa; Ogawa, Satoshi; Sakamoto, Michiie; Hata, Jun-Ichi; Umezawa, Akihiro

2005-01-01

306

Human Keratinocytes That Express hTERT and Also Bypass a p16INK4a-Enforced Mechanism That Limits Life Span Become Immortal yet Retain Normal Growth and Differentiation Characteristics  

Microsoft Academic Search

Normal human cells exhibit a limited replicative life span in culture, eventually arresting growth by a process termed senescence. Progressive telomere shortening appears to trigger senescence in normal human fibroblasts and retinal pigment epithelial cells, as ectopic expression of the telomerase catalytic subunit, hTERT, immortalizes these cell types directly. Telomerase expression alone is insufficient to enable certain other cell types

MARK A. DICKSON; WILLIAM C. HAHN; YASUSHI INO; VINCENT RONFARD; JENNY Y. WU; ROBERT A. WEINBERG; DAVID N. LOUIS; FREDERICK P. LI; JAMES G. RHEINWALD

2000-01-01

307

Perceived Risk of Predation Affects Reproductive Life-History Traits in Gambusia holbrooki, but Not in Heterandria formosa  

PubMed Central

Key to predicting impacts of predation is understanding the mechanisms through which predators impact prey populations. While consumptive effects are well-known, non-consumptive predator effects (risk effects) are increasingly being recognized as important. Studies of risk effects, however, have focused largely on how trade-offs between food and safety affect fitness. Less documented, and appreciated, is the potential for predator presence to directly suppress prey reproduction and affect life-history characteristics. For the first time, we tested the effects of visual predator cues on reproduction of two prey species with different reproductive modes, lecithotrophy (i.e. embryonic development primarily fueled by yolk) and matrotrophy (i.e. energy for embryonic development directly supplied by the mother to the embryo through a vascular connection). Predation risk suppressed reproduction in the lecithotrophic prey (Gambusia holbrokii) but not the matrotroph (Heterandria formosa). Predator stress caused G. holbrooki to reduce clutch size by 43%, and to produce larger and heavier offspring compared to control females. H. formosa, however, did not show any such difference. In G. holbrooki we also found a significantly high percentage (14%) of stillbirths in predator-exposed treatments compared to controls (2%). To the best of our knowledge, this is the first direct empirical evidence of predation stress affecting stillbirths in prey. Our results suggest that matrotrophy, superfetation (clutch overlap), or both decrease the sensitivity of mothers to environmental fluctuation in resource (food) and stress (predation risk) levels compared to lecithotrophy. These mechanisms should be considered both when modeling consequences of perceived risk of predation on prey-predator population dynamics and when seeking to understand the evolution of reproductive modes.

Mukherjee, Shomen; Heithaus, Michael R.; Trexler, Joel C.; Ray-Mukherjee, Jayanti; Vaudo, Jeremy

2014-01-01

308

Perceived risk of predation affects reproductive life-history traits in Gambusia holbrooki, but not in Heterandria formosa.  

PubMed

Key to predicting impacts of predation is understanding the mechanisms through which predators impact prey populations. While consumptive effects are well-known, non-consumptive predator effects (risk effects) are increasingly being recognized as important. Studies of risk effects, however, have focused largely on how trade-offs between food and safety affect fitness. Less documented, and appreciated, is the potential for predator presence to directly suppress prey reproduction and affect life-history characteristics. For the first time, we tested the effects of visual predator cues on reproduction of two prey species with different reproductive modes, lecithotrophy (i.e. embryonic development primarily fueled by yolk) and matrotrophy (i.e. energy for embryonic development directly supplied by the mother to the embryo through a vascular connection). Predation risk suppressed reproduction in the lecithotrophic prey (Gambusia holbrokii) but not the matrotroph (Heterandria formosa). Predator stress caused G. holbrooki to reduce clutch size by 43%, and to produce larger and heavier offspring compared to control females. H. formosa, however, did not show any such difference. In G. holbrooki we also found a significantly high percentage (14%) of stillbirths in predator-exposed treatments compared to controls (2%). To the best of our knowledge, this is the first direct empirical evidence of predation stress affecting stillbirths in prey. Our results suggest that matrotrophy, superfetation (clutch overlap), or both decrease the sensitivity of mothers to environmental fluctuation in resource (food) and stress (predation risk) levels compared to lecithotrophy. These mechanisms should be considered both when modeling consequences of perceived risk of predation on prey-predator population dynamics and when seeking to understand the evolution of reproductive modes. PMID:24551171

Mukherjee, Shomen; Heithaus, Michael R; Trexler, Joel C; Ray-Mukherjee, Jayanti; Vaudo, Jeremy

2014-01-01

309

Reproductive mode and life cycle of the ash dieback pathogen Hymenoscyphus pseudoalbidus.  

PubMed

Ash dieback caused by the fungal pathogen Hymenoscyphus pseudoalbidus is currently ravaging in Europe, killing Fraxinus excelsior and Fraxinus angustifolia trees of all age classes. The aim of this work was to elucidate aspects of the reproduction biology of this fungal pathogen and its cryptic, non-pathogenic sister species Hymenoscyphus albidus. The mating type (MAT) locus of both species was identified, partly sequenced and characterized. Whereas a heterothallic MAT organization was detected in H. pseudoalbidus, H. albidus was shown to be structurally homothallic. The molecular MAT determination of H. pseudoalbidus was confirmed by crossing experiments on sterile ash petioles. Crossings of strains exhibiting alternate MAT idiomorphs produced fertile apothecia whereas crosses of strains with identical MAT idiomorphs were never successful. Offspring genotyping with microsatellites (MSs) and the MAT marker confirmed that both parental strains were involved in apothecia formation. In addition, polymorphic MS were shown to follow Mendelian inheritance. However, for yet unknown reasons the MAT ratio of progenies of one successful cross revealed a significant segregation distortion. Based on the MAT sequences of H. pseudoalbidus a multiplex PCR was developed, allowing for a quick and reliable MAT determination. The PCR was applied to screen the MAT ratio of two H. pseudoalbidus populations derived from the country of the disease outbreak in Poland and two populations from the disease periphery in Switzerland. None of the screened populations showed a significant deviation from the 1:1 ratio, expected under random mating. Therefore, an initial clonal distribution through asexually produced conidiospores as observed for other fungal pathogens holds not true for H. pseudoalbidus. Instead, our data is highly supportive for a distribution through ascospores. Leaf petioles collected in the field were thoroughly analyzed for the number of different colonizing strains and their mating behavior. Up to eight different H. pseudoalbidus genotypes were found on a single petiole. Cross-fertilizations of strains on the same petiole and fertilizations of unknown strains from outside were found, indicating that fertilization is mediated by spermatia. The presented study complements our understanding of the life cycle of this highly destructive pathogen. The possibility to perform sexual crosses in the lab provides ample opportunities for further genetic studies of H. pseudoalbidus and related species in the future. PMID:23036580

Gross, A; Zaffarano, P L; Duo, A; Grünig, C R

2012-12-01

310

Cross-sectional and longitudinal relationships between cerebrospinal fluid biomarkers and cognitive function in people without cognitive impairment from across the adult life span.  

PubMed

IMPORTANCE Age-related cognitive decline among older individuals with normal cognition is a complex trait that potentially derives from processes of aging, inherited vulnerabilities, environmental factors, and common latent diseases that can progress to cause dementia, such as Alzheimer disease and vascular brain injury. OBJECTIVE To use cerebrospinal fluid (CSF) biomarkers to gain insight into this complex trait. DESIGN, SETTING, AND PARTICIPANTS Secondary analyses of an academic multicenter cross-sectional (n?=?315) and longitudinal (n?=?158) study of 5 neuropsychological tests (Immediate Recall, Delayed Recall, Trail Making Test Parts A and B, and Category Fluency) in cognitively normal individuals aged 21 to 100 years. MAIN OUTCOMES AND MEASURES To investigate the association of these cognitive function test results with age, sex, educational level, inheritance of the ?4 allele of the apolipoprotein E gene, and CSF concentrations of ?-amyloid 42 (A?42) and tau (biomarkers of Alzheimer disease) as well as F2-isoprostanes (measures of free radical injury). RESULTS Age and educational level were broadly predictive of cross-sectional cognitive performance; of the genetic and CSF measures, only greater CSF F2-isoprostane concentration was significantly associated with poorer executive function (adjusted R2 ?0.31). Longitudinal measures of cognitive abilities, except Category Fluency, also were associated broadly with age; of the genetic and CSF measures, only lower baseline CSF A?42 concentration was associated with longitudinal measures of immediate and delayed recall (marginal R2 ?0.31). CONCLUSIONS AND RELEVANCE Our results suggest that age and educational level accounted for a substantial minority of variance in cross-sectional or longitudinal cognitive test performance in this large group of cognitively normal adults. Latent Alzheimer disease and other diseases that produce free radical injury, such as vascular brain injury, accounted for a small amount of variation in cognitive test performance across the adult human life span. Additional genetic and environmental factors likely contribute substantially to age-related cognitive decline. PMID:24756381

Li, Ge; Millard, Steven P; Peskind, Elaine R; Zhang, Jing; Yu, Chang-En; Leverenz, James B; Mayer, Cynthia; Shofer, Jane S; Raskind, Murray A; Quinn, Joseph F; Galasko, Douglas R; Montine, Thomas J

2014-06-01

311

Recruitment and Retention Strategies for Minority or Poor Clinical Research Participants: Lessons From the Healthy Aging in Neighborhoods of Diversity Across the Life Span Study  

PubMed Central

Purpose of the study:?Investigating health disparities requires studies designed to recruit and retain racially and socioeconomically diverse cohorts. It is critical to address the barriers that disproportionately affect participation in clinical research by minorities and the socioeconomically disadvantaged. This study sought to identify and rectify these barriers to recruit and retain a biracial (African American and non-Hispanic White) and socioeconomically diverse cohort for a longitudinal study.?Design and Method:?The Healthy Aging in Neighborhoods of Diversity across the Life Span study is a 20-year longitudinal examination of how race and socioeconomic status influence the development of age-related health disparities. One goal was to create a multifactorial recruitment and retention strategy. The recruitment paradigm targeted known barriers and identified those unique to the study's urban environment. The retention paradigm mirrored the recruitment plan but was based on specifically developed approaches.?Results:?This cohort recruitment required attention to developing community partnerships, designing the research study to meet the study hypotheses and to provide benefit to participants, providing a safe community-based site for the research and creating didactics to develop staff cultural proficiency. These efforts facilitated study implementation and enhanced recruitment resulting in accrual of a biracial and socioeconomically diverse cohort of 3,722 participants.?Implications:?Recruiting and retaining minority or poor research participants is challenging but possible. The essential facets include clear communication of the research hypothesis, focus on providing a direct benefit for participants, and selection of a hypothesis that is directly relevant to the community studied

Ejiogu, Ngozi; Norbeck, Jennifer H.; Mason, Marc A.; Cromwell, Bridget C.; Zonderman, Alan B.; Evans, Michele K.

2011-01-01

312

Caloric restriction restores the chronological life span of the Goa1 null mutant of Candida albicans in spite of high cell levels of ROS.  

PubMed

The Candida albicans Goa1p is required for mitochondrial functions. In a strain lacking GOA1 (GOA31), respiration, mitochondrial membrane potential, complex I (CI) activity of the electron transport chain, and ATP synthesis are significantly decreased. A shortened chronological life span (CLS) of GOA31 occurs in 2% glucose that is associated with an increase in cell reactive oxidant species (ROS) and apoptosis. We now show that caloric restriction (CR) in media containing 0.5% glucose instead of 2% glucose-SC extends the CLS to the level of parental and gene-reconstituted strains. Paradoxically, ROS levels in GOA31 far exceed those of control strains in 0.5% glucose and, as a consequence, increased lipid peroxidation occurs even though CLS is restored. Microarray analysis was used to characterize transcriptional changes during CR in GOA31. We found that CR shifts cells of all strains to a non-glucose carbon metabolism (?-oxidation). Our model of ROS formation in GOA31 follows the paradigm that the generation of oxygen radicals from ?-oxidation of cell lipids via FADH(2) (CII) and NADH (CI) creates an unfavorable cellular FADH(2)/NADH ratio that causes a transient overload in CII activity resulting in excess free cell radicals. In GOA31 the CI and peroxisomal dysfunctions increase the levels of ROS compared to control strains. Recovery from high levels of ROS may be associated with an increase in iron and sugar transporters, as well as an anti-stress response that includes the SOD1 and GPX1. Thus, CR creates a favorable growth environment, but cells of GOA31 must overcome a high but transient ROS production. PMID:23063955

Chen, Hui; Calderone, Richard; Sun, Nuo; Wang, Yun; Li, Dongmei

2012-12-01

313

Life History and the Costs of Reproduction in Northern Great Plains Paddlefish (Polyodon spathula) as a Potential Framework for Other Acipenseriform Fishes  

Microsoft Academic Search

A 14-year investigation of a North American Acipenseriform fish, the paddlefish Polyodon spathula in the Yellowstone River, Montana, and North Dakota, USA has provided a detailed empirical framework of the life history in relation to the costs of reproduction for that species and potentially for closely related sturgeons. Nearly all aspects of life histories of males and females differed from

Dennis L. Scarnecchia; L. Fred Ryckman; Youngtaik Lim; Greg J. Power; Brad J. Schmitz; Jon A. Firehammer

2007-01-01

314

Genetic basis for reproductive diapause is correlated with life history traits within the Culex pipiens complex  

Microsoft Academic Search

The evolution of late season reproductive arrest (diapause) among female Culex pipiens mosquitoes allows them to overwinter in temperate climates, while females of the sibling species Culex quinquefasciatus do not exhibit the diapause phenotype. We present results for quantitative trait loci (QTL) analyses of two independent segregating populations derived from crosses between C. pipiens and C. quinquefasciatus . QTL for

A. Mori; J. Romero-Severson; D. W. Severson

2007-01-01

315

EFFECTS OF SUSPENDED SOLIDS AND SEDIMENT ON REPRODUCTION AND EARLY LIFE OF WARMWATER FISHES: A REVIEW  

EPA Science Inventory

The review of published literature and research reports revealed limited data for a few warmwater fish species concerning the impacts of suspended solids and sediments on reproductive success. Laboratory and field studies during the 1930-50s examined direct mortality as the resul...

316

An FXPRLamide Neuropeptide Induces Seasonal Reproductive Polyphenism Underlying a Life-History Tradeoff in the Tussock Moth  

PubMed Central

The white spotted tussock moth, Orgyia thyellina, is a typical insect that exhibits seasonal polyphenisms in morphological, physiological, and behavioral traits, including a life-history tradeoff known as oogenesis-flight syndrome. However, the developmental processes and molecular mechanisms that mediate developmental plasticity, including life-history tradeoff, remain largely unknown. To analyze the molecular mechanisms involved in reproductive polyphenism, including the diapause induction, we first cloned and characterized the diapause hormone-pheromone biosynthesis activating neuropeptide (DH-PBAN) cDNA encoding the five Phe-X-Pro-Arg-Leu-NH2 (FXPRLa) neuropeptides: DH, PBAN, and ?-, ?-, and ?-SGNPs (subesophageal ganglion neuropeptides). This gene is expressed in neurosecretory cells within the subesophageal ganglion whose axonal projections reach the neurohemal organ, the corpus cardiacum, suggesting that the DH neuroendocrine system is conserved in Lepidoptera. By injection of chemically synthetic DH and anti-FXPRLa antibody into female pupae, we revealed that not only does the Orgyia DH induce embryonic diapause, but also that this neuropeptide induces seasonal polyphenism, participating in the hypertrophy of follicles and ovaries. In addition, the other four FXPRLa also induced embryonic diapause in O. thyellina, but not in Bombyx mori. This is the first study showing that a neuropeptide has a pleiotropic effect in seasonal reproductive polyphenism to accomplish seasonal adaptation. We also show that a novel factor (i.e., the DH neuropeptide) acts as an important inducer of seasonal polyphenism underlying a life-history tradeoff. Furthermore, we speculate that there must be evolutionary conservation and diversification in the neuroendocrine systems of two lepidopteran genera, Orgyia and Bombyx, in order to facilitate the evolution of coregulated life-history traits and tradeoffs.

Uehara, Hiroshi; Senoh, Yukiko; Yoneda, Kyohei; Kato, Yoshiomi; Shiomi, Kunihiro

2011-01-01

317

Pre-treatment fertility counseling and fertility preservation improve quality of life in reproductive age women with cancer  

PubMed Central

Background The post-treatment quality of life (QOL) impacts of receiving pre-cancer-treatment infertility counseling and of pursuing fertility preservation have not been described in large-scale studies of reproductive age women with cancer. Methods 1041 women diagnosed between the ages of 18 and 40 responded to a retrospective survey and reported whether they received infertility counseling before cancer treatment and whether they took action to preserve fertility. Five cancer types were included: leukemia, Hodgkin’s disease, non-Hodgkin lymphoma, breast cancer, and gastrointestinal cancer. Validated QOL scales were used: Decision Regret Score (DRS), Satisfaction with Life Scale (SWLS), and World Health Organization QOL BREF (WHOQOL-BREF). Results 560 women (61%) whose treatment could affect fertility were counseled by the oncology team, 45 (5%) were counseled by fertility specialists, 36 (4%) took action to preserve fertility. Pre-treatment infertility counseling by a fertility specialist and an oncologist resulted in lower regret than counseling by an oncologist alone (8.4 vs. 11.0, P<0.0001). The addition of fertility preservation (6.6 vs. 11.0, P<0.0001) was also associated with even lower regret scores than counseling by an oncologist alone.. Further improvements were similarly seen in SWLS with the addition of fertility specialist counseling (23.0 vs. 19.8, P=0.09) or preserving fertility (24.0 vs. 19.0, P=0.05). Conclusions Receiving specialized counseling about reproductive loss and pursuing fertility preservation is associated with less regret and greater QOL for survivors, yet few patients are exposed to this potential benefit. Reproductive aged women should have expert counseling and be given the opportunity to make active decisions about preserving fertility.

Letourneau, Joseph M; Ebbel, Erin E; Katz, Patricia P; Katz, Audra; Ai, Wei Z; Chien, A Jo; Melisko, Michelle E; Cedars, Marcelle I; Rosen, Mitchell P

2011-01-01

318

Reproduction and Early-Life Accommodations of Landlocked Alewives to a Southern Range Extension  

Microsoft Academic Search

Reproduction and first-year growth and food habits of landlocked alewives Alosa pseudoharengus in Claytor Lake, Virginia were examined and compared to descriptions for populations in the species' established New England-Great Lakes range. Alewives in mesothermal (2–27 C) Claytor Lake are shorter-lived (3 years) but grow faster, mature earlier (age 1), and have higher relative and absolute fecundities than have been

Anthony A. Nigro; John J. Ney

1982-01-01

319

Studies on the Abies population of Mt. Shimagare II. Reproductive and life history traits  

Microsoft Academic Search

Reproductive traits are clarified for subalpine wave-regeneratedAbies populations in Central Japan, by observations at and near Mt. Shimagare, and by analyzing data from Mt. Asahi. Only dominant\\u000a trees produce seeds. They begin to reproduce at 50 years in age. Seeding interval is about 4 years. Averaged seed number produced\\u000a by an adult tree per annum does not change with tree

Takashi Kohyama

1982-01-01

320

Saving face, losing life: obeah pregnancy and reproductive impropriety in Southern Belize.  

PubMed

References to obeah pregnancy are widespread in southern Belize, where the belief in supernatural forces combines with Catholic teaching to create a conservative reproductive climate in which illegitimate pregnancy, reproductive misfortunes and maternal death are located in a discourse of shame. Obeah pregnancy is said to result when spiritual forces are unleashed through malicious human intent, causing bodily changes that resemble pregnancy. Death of the woman, however, usually occurs before prenatal confirmation; thus it is often unclear if an obeah pregnancy is a viable pregnancy or some other biomedical - or metaphysical - condition. This paper provides a case study of Petrona, whose story is unique in that she does not die from her purported obeah pregnancy; rather, she lives to bear the consequences of her reproductive behaviours that resulted in the stillbirth of a full-term foetus. Petrona was a traditional birth attendant who is trained to uphold biomedical antenatal protocols. Arguing that Petrona was not adequately educated to fulfill her own prenatal obligations, health care personnel sanctioned Petrona's midwifery practice and left her to process her 'shameful' situation. Ultimately, Petrona's story complicates the culturally disengaged narratives of maternal health and highlights the schism between medical knowledge and socioculturally influenced embodied experience. PMID:22085315

Maraesa, Aminata

2012-01-01

321

Seasonal trends in Ceratitis capitata reproductive potential derived from live-caught females in Greece  

PubMed Central

Reproductive data of individual insects are extremely hard to collect under natural conditions, thus the study of research questions related to oviposition has not advanced. Patterns of oviposition are often inferred only indirectly, through monitoring of host infestation, whereas the influence of age structure and several other factors on oviposition remains unknown. Using a new approach, in this article, we live-trapped wild Ceratitis capitata (Wiedemann) (Diptera: Tephritidae) females on the Greek island of Chios during two field seasons. For their remaining lifetime, these females were placed individually in small cages and their daily oviposition was monitored. Reproduction rates between cohorts from different collection dates were then compared. The results showed that in the different captive cohorts the average remaining lifetime and reproduction were highly variable within and between seasons. Multivariate regression analysis showed that the month of capture had a significant effect on captive life span, average daily reproduction, and patterns of egg laying. The effect of year was significant on reproduction, but not on captive life span. These differences between sampling periods probably reflect differences in the availability of hosts and other factors that vary during the season and affect age structure and reproduction. Using a non-parametric generalized additive model, we found a statistically significant correlation between the captive life span and the average daily reproduction. These findings and the experimental approach have several important implications.

Kouloussis, Nikos A.; Papadopoulos, Nikos T.; Katsoyannos, Byron I.; Muller, Hans-Georg; Wang, Jane-Ling; Su, Yu-Ru; Molleman, Freerk; Carey, James R.

2012-01-01

322

Life expectancy, economic inequality, homicide, and reproductive timing in Chicago neighbourhoods.  

PubMed Central

In comparisons among Chicago neighbourhoods, homicide rates in 1988-93 varied more than 100-fold, while male life expectancy at birth ranged from 54 to 77 years, even with effects of homicide mortality removed. This "cause deleted" life expectancy was highly correlated with homicide rates; a measure of economic inequality added significant additional prediction, whereas median household income did not. Deaths from internal causes (diseases) show similar age patterns, despite different absolute levels, in the best and worst neighbourhoods, whereas deaths from external causes (homicide, accident, suicide) do not. As life expectancy declines across neighbourhoods, women reproduce earlier; by age 30, however, neighbourhood no longer affects age specific fertility. These results support the hypothesis that life expectancy itself may be a psychologically salient determinant of risk taking and the timing of life transitions.

Wilson, M.; Daly, M.

1997-01-01

323

Life prolonging effect of butylated hydroxy anisole in Callosobruchus maculatus F. (Coleoptera: Bruchidae).  

PubMed

The present study deals with the effect of butylated hydroxy anisole (BHA), an antioxidant, on longevity and fecundity of insects infesting BHA soaked seeds of Vigna radiata. Median (LT(50)) and maximum (LT(100)) life spans as well as post-reproductive period of the insect reared on optimal concentration (1 mM) of antioxidant soaked seeds were higher than the control. However, the reproductive period of the females and the number of eggs laid/female declined. The results are indicative of the increased life span of the insects on BHA feeding at the cost of the reproductive period. PMID:15374382

Mahajan, S; Garg, S K

1992-01-01

324

Reproductive success in presenescent common gulls (Larus canus): the importance of the last year of life.  

PubMed Central

Survival selection against individuals of inferior quality (measured as breeding success) has been proposed to account for the increase in average reproductive success with advancing age in presenescent birds. This so-called selection hypothesis relies on quality-dependent survival. In the present breeding performance study of common gulls, Larus canus, this assumption was not verified. In particular, omitting the last breeding year from the analysis resulted in the disappearance of the correlation between breeding success and survival. A positive correlation in the full dataset was thus solely based on the poor breeding success of ultimate breeders. Indeed, presenescent individuals were shown to have a specifically low breeding success in their terminal breeding event. The poor success of ultimate breeders thus reflects an abruptly declined condition rather than the birds' overall quality. A comparison of the survival of poor and good performers, involving last-time breeders, thus needs not to be a proper test of the selection hypothesis. Longitudinal analysis revealed a steady increase of individual breeding success until the tenth breeding year. The results suggest that an increase of breeding success with age often found in cross-sectional analyses is primarily a result of age-related improvements of competence and/or increased reproductive effort.

Rattiste, Kalev

2004-01-01

325

Reproductive bionomics and life history traits of three gammaridean amphipods, Cymadusa filosa Savigny, Ampithoe laxipodus Appadoo and Myers and Mallacoota schellenbergi Ledoyer from the tropical Indian Ocean (Mauritius)  

NASA Astrophysics Data System (ADS)

The reproductive bionomics and life history traits of two corophiid amphipods ( Ampithoe laxipodus, Cymadusa filosa) and one melitid ( Mallacoota schellenbergi) were studied in Mauritius (Indian Ocean) for the period March 1999 to February 2000. Results on the population structure, monthly size class variations, sex ratio, female reproductive states and fecundity are presented. The study demonstrates multivoltinism and continuous reproduction in the three species. Increase in number of juveniles was observed in warmer months for C. filosa and A. laxipodus. Sexual maturity was attained at smaller sizes in warmer months in the three species. Linear relationship on body length and number of eggs in brood pouch are presented. Size-independent analysis of egg number revealed a decrease in number of eggs in cooler months. Sex ratio is male skewed in M. schellenbergi and female skewed in C. filosa and A. laxipodus. Some of the plausible explanations for the reproductive strategies adopted by these three species in a tropical system are discussed.

Appadoo, Chandani; Myers, Alan A.

2004-12-01

326

Reproductive Behavior and Fitness Components in Male Drosophila melaogaster are Non-Linearly Affected by the Number of Male Co-Inhabitants Early in Adult Life  

PubMed Central

Although multiple lines of evidence suggest that early adult life is very important in shaping the reproductive behavior of males, few studies have looked at the fitness consequences of the variation in reproductive behavior induced by differences in early life experience of males. Using a long term laboratory adapted population of Drosophila melanogaster Meigen (Diptera: Drosophilidae), early life experience, in terms of co-inhabitant numbers, was found to affect male mating behavior and at least one fitness component. However, in contrast to previous studies, a non-linear relationship was found between early life experience and fitness components and a significant effect of co-inhabitant number on copulation duration and sperm defense. Both these traits showed a sharp increase as the co-inhabitant numbers changed from 1 to 16. However, there was a decline in the trait values as the co-inhabitant number increased further. The probable causes for the observed non-linear pattern of responses are discussed.

Nandy, B.; Prasad, N. G.

2011-01-01

327

3. VIEW NORTH SHOWING FIXED SPAN, COVERED SPAN, MOVEABLE TRANSITION ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

3. VIEW NORTH SHOWING FIXED SPAN, COVERED SPAN, MOVEABLE TRANSITION SPAN AND PONTOON FLOATING SPAN - Lacey V. Murrow Memorial Floating Bridge, Spanning Lake Washington at I-90, Seattle, King County, WA

328

Quality of life, reproduction and sexuality after stem cell transplantation with partially T-cell-depleted grafts and after conditioning with a regimen including total body irradiation  

Microsoft Academic Search

Thirty-four men and 36 women (median age 43 and 45 years, respectively) underwent stem cell transplantation (SCT) for acute leukaemia in first complete remission or chronic myelogenous leukaemia in first chronic phase between 1981 and 2001 from HLA-identical siblings. The conditioning regimen included TBI and all grafts were partially depleted of T cells. Changes in quality of life (QOL), reproduction

J. J. M. Claessens; C. C. M. Beerendonk; A. V. M. B. Schattenberg; AVMB Schattenberg

2006-01-01

329

Span of control matters.  

PubMed

Prompted by manager concerns about span of control, a large, integrated health system set out to determine if span of control really mattered. Was there something to it, or was it just an excuse for poor performance? A team of middle managers studied the problem and ultimately demonstrated a strong relationship between span of control and employee engagement. Consequently, it was decided to add 4 management positions to note the effect. One year later, positive changes were observed in employee engagement scores in all 4 areas. This study suggests careful review of manager spans of control to address the untoward effects of large spans of control on employee engagement. PMID:15367902

Cathcart, Deb; Jeska, Susan; Karnas, Joan; Miller, Sue E; Pechacek, Judy; Rheault, Lolita

2004-09-01

330

SPAN: Ocean science  

NASA Technical Reports Server (NTRS)

The Space Physics Analysis Network (SPAN) is a multi-mission, correlative data comparison network which links space and Earth science research and data analysis computers. It provides a common working environment for sharing computer resources, sharing computer peripherals, solving proprietary problems, and providing the potential for significant time and cost savings for correlative data analysis. This is one of a series of discipline-specific SPAN documents which are intended to complement the SPAN primer and SPAN Management documents. Their purpose is to provide the discipline scientists with a comprehensive set of documents to assist in the use of SPAN for discipline specific scientific research.

Thomas, Valerie L.; Koblinsky, Chester J.; Webster, Ferris; Zlotnicki, Victor; Green, James L.

1987-01-01

331

[Mutation of Indy(p115) increases the life expectancy of imago of Drosophila melanogaster depending on sex and genetic background].  

PubMed

The Indyp115 allele in heterozygous state almost doubles the life span of adult Drosophila melanogaster, and this effect largely depends on the strain used for obtaining heterozygotes. Male and female life span depends on Indyp115 to a different degree. Apart from Indyp115 heterozygotes, sexual dimorphism for life span was also observed in strain Hikone-AW, but not in OregonR and TM3 balancer. In heterozygotes Indyp115/OR, both the average life span and female reproductive period increased as compared to OR control. No substantial increase in female reproductive period in Indyp115/Hk heterozygotes was found. In homozygotes for allele Indyp115, we have previously revealed two phases of embryotic lethality and lethality at the larval and pupa stages. Thus, allele Indyp115 has a double and opposite effect on Drosophila viability. On the one hand, it extends the life span of adult flies, on the other, decreases survival at preimaginal stages. PMID:15174281

Bulgakova, N A; Trunova, S A; Omel'ianchuk, L V

2004-04-01

332

Reproductive styles and life history variables relative to exploitation and management of Sebastes stocks  

Microsoft Academic Search

Synopsis  The characteristics of lightly and heavily exploited Pacific ocean perch,Sebastes alutus, stocks are evaluated relative to the predictions of life history theory. These long-lived species (50–100 year lifespan)\\u000a show limited phenotypic plasticity and have little buffering against the effects of reduced lifespan. Reduced stock abundance\\u000a has generated some compensatory increase in growth rate. Length at first maturity varies only slightly

Bruce M. Leaman

1991-01-01

333

A review of the life history, reproduction and phenology of Gracilaria  

Microsoft Academic Search

The basic life history of the red alga Gracilaria is of the three-phase Polysiphonia type but a number of species show deviations. Plants can bear both gametangia and tetrasporangia, either on separate parts\\u000a of the thallus or on the same. Explanations include the in situ germination of tetraspores (allowing gametophytic thalli to be epiphytic on tetrasporophytes), the coalescence of spores

Christophe Destombe

1995-01-01

334

Reflected Roof Plan (Span A), Ground Floor Plan (Span A) ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Reflected Roof Plan (Span A), Ground Floor Plan (Span A) - Sulphite Railroad Bridge, Former Boston & Maine Railroad (originally Tilton & Franklin Railroad) spanning Winnipesautee River, Franklin, Merrimack County, NH

335

Communicating Employability Enhancement throughout the Life-Span: A National Intervention Program Aimed at Combating Age-Related Stereotypes at the Workplace  

ERIC Educational Resources Information Center

The stimulation of lifelong employability of employees is one of today's challenges in all sectors of the Dutch society. In this article, we will outline the historical context of the life-long employability issue in the Netherlands, and provide an overview of current business responses to the issue. We will discuss key obstacles for improving…

van Selm, Martine; Van der Heijden, Beatrice I. J. M.

2013-01-01

336

Insulin-like growth factor-I extends in vitro replicative life span of skeletal muscle satellite cells by enhancing G1/S cell cycle progression via the activation of phosphatidylinositol 3'-kinase/Akt signaling pathway  

NASA Technical Reports Server (NTRS)

Interest is growing in methods to extend replicative life span of non-immortalized stem cells. Using the insulin-like growth factor I (IGF-I) transgenic mouse in which the IGF-I transgene is expressed during skeletal muscle development and maturation prior to isolation and during culture of satellite cells (the myogenic stem cells of mature skeletal muscle fibers) as a model system, we elucidated the underlying molecular mechanisms of IGF-I-mediated enhancement of proliferative potential of these cells. Satellite cells from IGF-I transgenic muscles achieved at least five additional population doublings above the maximum that was attained by wild type satellite cells. This IGF-I-induced increase in proliferative potential was mediated via activation of the phosphatidylinositol 3'-kinase/Akt pathway, independent of mitogen-activated protein kinase activity, facilitating G(1)/S cell cycle progression via a down-regulation of p27(Kip1). Adenovirally mediated ectopic overexpression of p27(Kip1) in exponentially growing IGF-I transgenic satellite cells reversed the increase in cyclin E-cdk2 kinase activity, pRb phosphorylation, and cyclin A protein abundance, thereby implicating an important role for p27(Kip1) in promoting satellite cell senescence. These observations provide a more complete dissection of molecular events by which increased local expression of a growth factor in mature skeletal muscle fibers extends replicative life span of primary stem cells than previously known.

Chakravarthy, M. V.; Abraha, T. W.; Schwartz, R. J.; Fiorotto, M. L.; Booth, F. W.

2000-01-01

337

4. DETAIL VIEW FIXED SPAN INCLUDING TRUSS, MOVEABLE SPAN WHICH ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

4. DETAIL VIEW FIXED SPAN INCLUDING TRUSS, MOVEABLE SPAN WHICH THE NEXT UNIT TO THE RIGHT, AND FIRST UNIT OF PONTOON FLOATING SPAN. - Lacey V. Murrow Memorial Floating Bridge, Spanning Lake Washington at I-90, Seattle, King County, WA

338

Intermediary metabolism and life-history trade-offs: differential metabolism of amino acids underlies the dispersal-reproduction trade-off in a wing-polymorphic cricket.  

PubMed

Although the differential flow of metabolites through alternate pathways of intermediary metabolism is thought to be an important functional cause of life-history trade-offs, this phenomenon remains understudied. Using a radiolabeled amino acid, we quantified genetic differences in in vivo amino acid metabolism between morphs of the wing-polymorphic cricket Gryllus firmus that trade off early-age reproduction and dispersal capability. Lines selected for the flight-capable morph, which delays reproduction, oxidized a greater proportion of radiolabeled glycine and converted a greater amount into somatic lipid, mainly triglyceride (flight fuel). By contrast, lines selected for the flightless, reproductive morph converted a substantially greater proportion of glycine into ovarian protein. Compensatory interactions between amino acid and lipid metabolism make up a key aspect of specialization for dispersal versus reproduction in G. firmus: increased oxidation of amino acids by the flight-capable morph spares fatty acid for enhanced conversion into triglyceride flight fuel. By contrast, increased oxidation of fatty acid by the flightless morph spares amino acids for enhanced biosynthesis of ovarian protein. Studies of amino acid and lipid metabolism in G. firmus currently represent the most detailed analyses of genetic modifications of intermediary metabolism that underlie a functionally important life-history trade-off found in natural populations. PMID:16609924

Zera, Anthony J; Zhao, Zhangwu

2006-06-01

339

Reproduction, survival, and life table parameters of the predatory mite Cheyletus malaccensis (Acari: Cheyletidae) at various constant temperatures.  

PubMed

Reproduction, survival, and life table parameters of the predatory mite Cheyletus malaccensis Oudemans were evaluated at six constant temperatures: 17.5, 20, 25, 30, 32.5 and 35°C, feeding on Tyrophagus putrescentiae (Schrank). Preoviposition period of fertilized and virgin females varied with temperature from ca. 9 days at 17.5°C to ca. 1.5 day at 32.5°C and then increased to ca. 3 days at 35°C. Virgin female oviposition period was significantly shorter than for fertilized females at the temperatures examined with the exception of 17.5°C. The mean total number of eggs per fertilized (169.7 ± 6.6) and virgin female (60.7 ± 4.3) was highest at the temperature of 30°C. The data indicated a significant positive and nearly doubling effect of fertilization on female fecundity at the temperatures examined with the exception of 17.5°C. Age-specific fecundity was described by a temperature dependent model from which the maximum daily fecundity rate was estimated for fertilized and virgin females at 10.3 (at 30°C) and 6.8 (at 32.5°C) eggs/female, respectively. Virgin female longevity was significantly shorter than for fertilized females at 20, 30 and 32.5°C, and decreased from ca. 57 days at 17.5°C to ca. 17 days at 35°C. The Weibull function that was used to describe the age specific survival of fertilized and virgin females produced excellent fits to the survival data. Estimates of intrinsic rate of increase, net reproductive rate, mean generation time, doubling time and finite rate of increase, were obtained. The r(m) value increased with temperature from 0.03 (day(-1)) at 17.5°C to 0.21 (day(-1)) at 32.5°C, after which it decreased to 0.15 (day(-1)) at 35°C. These data indicate that C. malaccensis can reproduce at temperatures between 17.5 and 35°C and can be used for biological control of astigmatid mites within the temperature range where the pest occurs. PMID:21287248

Palyvos, Nickolas E; Emmanouel, Nickolas G

2011-06-01

340

Life-history traits of Amur sleeper, Perccottus glenii , in the invaded Vistula River: early investment in reproduction but reduced growth rate  

Microsoft Academic Search

In recent decades, Amur sleeper is one of the most invasive fish species in Eastern and Central Europe. Generally, it is assumed\\u000a that success of an invasive species can largely depend on the plasticity of its life-history traits, e.g., indicated by higher\\u000a investment in reproduction in the initial stage of its invasion. On the other hand, such energy allocation to

Grabowska Joanna; Pietraszewski Dariusz; Przybylski Miros?aw; Tarkan Ali Serhan; Marsza? Lidia; Lampart-Ka?u?niacka Magdalena

2011-01-01

341

Threshold-like dose of local beta irradiation repeated throughout the life span of mice for induction of skin and bone tumors  

SciTech Connect

The backs of female ICR mice were irradiated with beta rays from 90Sr-90Y three times a week throughout life. Previously we observed 100% tumor incidence at five different dose levels ranging from 1.5 to 11.8 Gy per exposure, but no tumor on repeated irradiation with 1.35 Gy for 300 days. In the present study, delay of tumor development was again seen at a dose of 1.5 Gy per exposure, with further delay at 1.0 Gy. The final tumor incidence was 100% with these two doses. At 0.75 Gy per exposure, no tumor appeared within 790 days after the start of irradiation, but one osteosarcoma and one squamous cell carcinoma did finally appear. These findings indicate a threshold-like response of tumor induction in this repeated irradiation system and further suggest that the apparent threshold may be somewhat less than 0.75 Gy per exposure.

Ootsuyama, A.; Tanooka, H. (National Cancer Center Research Institute, Tokyo (Japan))

1991-01-01

342

'The brain is the organ of longevity': Introduction to G. A. Sacher's free-energy hypothesis of life-span enhancement  

SciTech Connect

No experiment reported to date constitutes an adequate test in the sense of supplying comprehensive information on survival time, metabolic rate, food consumption and utilization, body mass, anatomical integrity (especially that of the skeletal and nervous systems), status of the immune and endocrine systems, and physiological and behavioral competence in the wake of chronic exposure to a moderately thermalizing radio field. Some reports do provide data on one or more of the important end points, usually in association with a single exposure or a limited number of brief exposures. One must distinguish between prolongation of life in senescence and enhancement of longevity based on actual retardation of the rate of aging. More, retardation of aging, if sorely taxed at the expense of quality of living, is no bargain. Some hibernators live relatively long lives, but the torpor of hibernation--a prolonged period of somnolence and greatly reduced metabolic activity--is hardly the stuff of a vibrant psychological existence.

Justesen, D.R.

1981-10-01

343

Reproductive value in a complex life cycle: heat tolerance of the pitcher-plant mosquito, Wyeomyia smithii  

Microsoft Academic Search

Because mortality accumulates with age, Fisher proposed that the strength of selection acting on survival should increase from birth up to the age of first reproduction. Hamilton later theorized that the strength of selection acting on survival should not change from birth to age at first reproduction. As organisms in nature do not live in uniform environments but, rather, experience

P. A. ZANI; L. W. COHNSTAEDT; D. CORBIN; W. E. BRADSHAW; C. M. HOLZAPFEL

2004-01-01

344

Terminal Investment: Individual Reproduction of Ant Queens Increases with Age  

PubMed Central

The pattern of age-specific fecundity is a key component of the life history of organisms and shapes their ecology and evolution. In numerous animals, including humans, reproductive performance decreases with age. Here, we demonstrate that some social insect queens exhibit the opposite pattern. Egg laying rates of Cardiocondyla obscurior ant queens increased with age until death, even when the number of workers caring for them was kept constant. Cardiocondyla, and probably also other ants, therefore resemble the few select organisms with similar age-specific reproductive investment, such as corals, sturgeons, or box turtles (e.g., [1]), but they differ in being more short-lived and lacking individual, though not social, indeterminate growth. Furthermore, in contrast to most other organisms, in which average life span declines with increasing reproductive effort, queens with high egg laying rates survived as long as less fecund queens.

Heinze, Jurgen; Schrempf, Alexandra

2012-01-01

345

The Years of Uncertainty: Eighth Grade Family Life Education.  

ERIC Educational Resources Information Center

The family life sex education unit for eighth graders, "The Years of Uncertainty," consists of a series of daily lesson plans that span a 29-day period of one-hour class sessions. Topics covered are: problem solving, knowledge and attitudes, male and female reproductive systems, conception, pregnancy, birth, birth defects, venereal disease,…

Carson, Mary, Ed.; And Others

346

Impact of multimorbidity: acute morbidity, area of residency and use of health services across the life span in a region of south Europe  

PubMed Central

Background Concurrent diseases, multiple pathologies and multimorbidity patterns are topics of increased interest as the world’s population ages. To explore the impact of multimorbidity on affected patients and the consequences for health services, we designed a study to describe multimorbidity by sex and life-stage in a large population sample and to assess the association with acute morbidity, area of residency and use of health services. Methods A cross-sectional study was conducted in Catalonia (Spain). Participants were 1,749,710 patients aged 19+ years (251 primary care teams). Primary outcome: Multimorbidity (?2 chronic diseases). Secondary outcome: Number of new events of each acute disease. Other variables: number of acute diseases per patient, sex, age group (19–24, 25–44, 45–64, 65–79, and 80+ years), urban/rural residence, and number of visits during 2010. Results Multimorbidity was present in 46.8% (95% CI, 46.7%-46.8%) of the sample, and increased as age increased, being higher in women and in rural areas. The most prevalent pair of chronic diseases was hypertension and lipid disorders in patients older than 45 years. Infections (mainly upper respiratory infection) were the most common acute diagnoses. In women, the highest significant RR of multimorbidity vs. non-multimorbidity was found for teeth/gum disease (aged 19–24) and acute upper respiratory infection. In men, this RR was only positive and significant for teeth/gum disease (aged 65–79). The adjusted analysis showed a strongly positive association with multimorbidity for the oldest women (80+ years) with acute diseases and women aged 65–79 with 3 or more acute diseases, compared to patients with no acute diseases (OR ranged from 1.16 to 1.99, p < 0.001). Living in a rural area was significantly associated with lower probability of having multimorbidity. The odds of multimorbidity increased sharply as the number of visits increased, reaching the highest probability in those aged 65–79 years. Conclusions Multimorbidity is related to greater use of health care services and higher incidence of acute diseases, increasing the burden on primary care services. The differences related to sex and life-stage observed for multimorbidity and acute diseases suggest that further research on multimorbidity should be stratified according to these factors.

2014-01-01

347

Chemical genetic screen identifies lithocholic acid as an anti-aging compound that extends yeast chronological life span in a TOR-independent manner, by modulating housekeeping longevity assurance processes  

PubMed Central

In chronologically aging yeast, longevity can be extended by administering a caloric restriction (CR) diet or some small molecules. These life-extending interventions target the adaptable target of rapamycin (TOR) and cAMP/protein kinase A (cAMP/PKA) signaling pathways that are under the stringent control of calorie availability. We designed a chemical genetic screen for small molecules that increase the chronological life span of yeast under CR by targeting lipid metabolism and modulating housekeeping longevity pathways that regulate longevity irrespective of the number of available calories. Our screen identifies lithocholic acid (LCA) as one of such molecules. We reveal two mechanisms underlying the life-extending effect of LCA in chronologically aging yeast. One mechanism operates in a calorie availability-independent fashion and involves the LCA-governed modulation of housekeeping longevity assurance pathways that do not overlap with the adaptable TOR and cAMP/PKA pathways. The other mechanism extends yeast longevity under non-CR conditions and consists in LCA-driven unmasking of the previously unknown anti-aging potential of PKA. We provide evidence that LCA modulates housekeeping longevity assurance pathways by suppressing lipid-induced necrosis, attenuating mitochondrial fragmentation, altering oxidation-reduction processes in mitochondria, enhancing resistance to oxidative and thermal stresses, suppressing mitochondria-controlled apoptosis, and enhancing stability of nuclear and mitochondrial DNA.

Goldberg, Alexander A.; Richard, Vincent R.; Kyryakov, Pavlo; Bourque, Simon D.; Beach, Adam; Burstein, Michelle T.; Glebov, Anastasia; Koupaki, Olivia; Boukh-Viner, Tatiana; Gregg, Christopher; Juneau, Mylene; English, Ann M.; Thomas, David Y.; Titorenko, Vladimir I.

2010-01-01

348

Genetic Dissection of Late-Life Fertility in Caenorhabditis elegans  

PubMed Central

The large post-reproductive life span reported for the free-living hermaphroditic nematode, Caenorhabditis elegans, which lives for about 10 days after its 5-day period of self-reproduction, seems at odds with evolutionary theory. Species with long post-reproductive life spans such as mammals are sometimes explained by a need for parental care or transfer of information. This does not seem a suitable explanation for C elegans. Previous reports have shown that C elegans can regain fertility when mated after the self-fertile period but did not report the functional limits. Here, we report the functional life span of the C elegans germ line when mating with males. We show that C elegans can regain fertility late in life (significantly later than in previous reports) and that the end of this period corresponds quite well to its 3-week total life span. Genetic analysis reveals that late-life fertility is controlled by conserved pathways involved with aging and dietary restriction.

Wu, Deqing; Park, Sang-Kyu; Cypser, James R.; Tedesco, Patricia M.; Phillips, Patrick C.; Johnson, Thomas E.

2011-01-01

349

New prospects for a prolonged functional life-span of artificial hip joints by using the material combination polyethylene/aluminium oxide ceramin/metal.  

PubMed

Investigations over the years have shown that the mirror-finished Al2O3 ceramic is a much more suitable frictional counterpart to ultrahigh molecular weight (UHMW) polyethylene than metal. Despite the extremely gread hardness difference between polyethylene and Al2O3 ceramic, a considerable lower wear rate is obtained for the polyethylene socked with this new low-friction material combination. The unexpectedly favorable tribological behavior of this ceramic material in contact with polyethylene may be attributed to the following factors: better values for corrosion resistance characteristics, wettability with liquids, surfact gloss, hardness, and scratch resistance of the ceramic material in comparison with those of the hitherto used metallic implant materials (AISI-316L steel or cast Co-Cr-Mo alloy). It appears that, by using this new combination of materials for the socket and the ball, it will be possible to prolong the service life of artificial hip joints considerably without having effecy any fundamental changes in the present design and implantation principle retaining the hitherto used anchorage shaft made of wrought Co-Ni-Cr-Mo-Ti alloy Protasul-10 of extremely high corrosion fatigue strength. PMID:559675

Semlitsch, M; Lehmann, M; Weber, H; Doerre, E; Willert, H G

1977-07-01

350

What Deficits in Sexual and Reproductive Health Knowledge Exist among Women with Cystic Fibrosis? A Systematic Review  

ERIC Educational Resources Information Center

The life span of patients with cystic fibrosis (CF) continues to extend due to advances in treatments and care. The rate of pregnancy for female patients with CF has also continued to rise. The purpose of this study was to systematically review the available literature on female patients with CF and their knowledge of sexual and reproductive…

Gage, L. Ashley

2012-01-01

351

View of approach span and movable span, looking southeast from ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

View of approach span and movable span, looking southeast from navy land. Note that navigational channel exists only on north side of movable span. - Naval Supply Annex Stockton, Rough & Ready Island, Stockton, San Joaquin County, CA

352

Truncated span west of verticallift span, from SW. Pennsylvania ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Truncated span west of vertical-lift span, from SW. - Pennsylvania & New Jersey Railroad, Delaware River Bridge, Spanning Delaware River, south of Betsy Ross Bridge (State Route 90), Philadelphia, Philadelphia County, PA

353

Reflected Deck Plan (Span A), Longitudinal Section XX (Span A) ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Reflected Deck Plan (Span A), Longitudinal Section X-X (Span A) - Sulphite Railroad Bridge, Former Boston & Maine Railroad (originally Tilton & Franklin Railroad) spanning Winnipesautee River, Franklin, Merrimack County, NH

354

Reproductive System  

Microsoft Academic Search

\\u000a Reproduction differs from other physiological functions in the sense that it is not essential for survival of an individual,\\u000a only for that of the species. However, the prevalence of infertility is on the rise, and it seriously affects the quality\\u000a of life of the couples affected. Since both contraception and infertility problems concern young, otherwise healthy individuals,\\u000a the possibilities to

M. Poutanen; F.-P. Zhang; S. Rulli; S. Mäkelä; P. Sipilä; J. Toppari; I. Huhtaniemi

355

An evaluation of fish early life stage tests for predicting reproductive and longer-term toxicity from plant protection product active substances.  

PubMed

The chronic toxicity of chemicals to fish is routinely assessed by using fish early life stage (ELS) test results. Fish full life cycle (FLC) tests are generally required only when toxicity, bioaccumulation, and persistence triggers are met or when there is a suspicion of potential endocrine-disrupting properties. This regulatory approach is based on a relationship between the results of fish ELS and FLC studies first established more than 35 yrs ago. Recently, this relationship has been challenged by some regulatory authorities, and it has been recommended that more substances should undergo FLC testing. In addition, a project proposal has been submitted to the Organisation for Economic Cooperation and Development (OECD) to develop a fish partial life cycle (PLC) test including a reproductive assessment. Both FLC and PLC tests are animal- and resource-intensive and technically challenging and should therefore be undertaken only if there is clear evidence that they are necessary for coming to a regulatory decision. The present study reports on an analysis of a database of paired fish ELS and FLC endpoints for plant protection product active substances from European Union draft assessment reports and the US Environmental Protection Agency Office of Pesticide Programs Pesticide Ecotoxicity Database. Analysis of this database shows a clear relationship between ELS and FLC responses, with similar median sensitivity across substances when no-observed-effect concentrations (NOECs) are compared. There was also no indication that classification of a substance as a mammalian reproductive toxicant leads to more sensitive effects in fish FLC tests than in ELS tests. Indeed, the response of the ELS tests was generally more sensitive than the most sensitive reproduction NOEC from a FLC test. This analysis indicates that current testing strategies and guidelines are fit for purpose and that there is no need for fish full or partial life cycle tests for most plant protection product active substances. Environ Toxicol Chem 2014;33:1874-1878. © 2014 SETAC. PMID:24799351

Wheeler, James R; Maynard, Samuel K; Crane, Mark

2014-08-01

356

Life-span effects of ionizing radiation in the beagle dog: A summary account of four decades of research funded by the US Department of Energy and its predecessor agencies  

SciTech Connect

Nearly 40 years ago, the US Atomic Energy Commission made a far- reaching commitment to the support of life-span radiation-effects studies in a relatively long-lived animal, the beagle dog. Something in the range of 200 million dollars has already been spent on a group of closely related experiments, many of which are only now coming to fruition. Responsible fiscal management of these studies, directed toward securing an optimum return from past investments, and toward creative planning of future directions, requires a comprehensive view of this total effort. This report is designed to provide that comprehensive view. This is primarily intended as a research management document. Evaluation and interpretation are tasks for those directly involved in conducting these experiments. The limited objective of the present document is to describe what has been done, to give some of the background for why it was done, to describe results already realized and applications that have been made of these results -- all in a manner designed to display the total effort rather than piecemeal details. While proposing no specific answers to the questions ''Where do we go from here.''it is hoped that the document will provide a basis for approaching that question in an informed manner. The maintenance of a continuity of scientific understanding and direction in these experiments, which often continue beyond the initiating investigators' working life, is no small part of the problem involved in conducting these experiments.

Thompson, R.C.

1989-01-01

357

C-SPAN Classroom  

NSDL National Science Digital Library

Over the past several decades, C-SPAN has brought many hours of fascinating programming to the generally curious. Many teachers have used their programming to edify their students about various aspects of US government, and now C-SPAN has created this very nice site to complement those informal activities. The formal mission of the C-SPAN Classroom site is "to enhance the teaching of Civics & U.S. Government through C-SPAN's primary source programming." Visitors can start their journey by viewing the "Clip of the Week", and then looking through the other thematic sections on the site, which include "Principles of Government", "Legislative Branch", and "Political Participation". Along with each clip, users can also view a short clip description, and take advantage of the discussion questions as well. Visitors will need to complete a short free registration form to access all of the clips, and this only takes a few minutes. This site is quite a delight, and for anyone who teaches civics and related fields, it will most likely become an essential online resource.

358

Toxicity of copper-spiked sediments to Tubifex tubifex (Oligochaeta, Tubificidae): Comparison of the 28-day reproductive bioassay with an early-life-stage bioassay  

SciTech Connect

Two sediment bioassay methods using Tubifex tubifex (Mueller, 1774) as the test species were compared. The first was an adult reproduction test, the second an early-life-stage survival test. The duration of both bioassays is 28 d and the amount of work required was similar; they may be useful alternatives to each other in different circumstances (e.g., the early life stage bioassay could be carried out with smaller volumes of sediment). The two bioassays were performed simultaneously on copper-spiked sediments. Sediments from two freshwater and two terrestrial sites were used; five separate, nonsimultaneous experiments were performed, one for each sediment or soil and a further experiment with soil with a good supplement. In the adult bioassay, there were large differences in the production of cocoons, eggs, and young among the control treatments of the five experiments. There were also major differences in the NOEC and LOEC for copper between the tested substrates. The early life stage bioassay appears to be less sensitive to copper toxicity than the adult reproductive bioassay since NOECs and LOECs are higher for early survival than for the most sensitive endpoints of the adult bioassay in three experiments out of five.

Vecchi, M.; Pasteris, A.; Bonomi, G. (Univ. degli Studi di Bologna (Italy). Dipt. di Biologia Evoluzionistica Sperimentale); Reynoldson, T.B. (Environment Canada, Burlington, Ontario (Canada). National Water Research Inst.)

1999-06-01

359

Autobiographical Memory from a Life Span Perspective  

ERIC Educational Resources Information Center

This comparative study (i.e., three age groups, three measures) explores the distribution of retrospective and prospective autobiographical memory data across the lifespan, in particular the bump pattern of disproportionally higher recall of memories from the ages 10 to 30, as generally observed in older age groups, in conjunction with the…

Schroots, Johannes J. F.; van Dijkum, Cor; Assink, Marian H. J.

2004-01-01

360

Mental Illness Linked to Shortened Life Spans  

MedlinePLUS

... officials to place a much higher priority on mental health. Findings from the study were released online May 23 in the journal World Psychiatry . SOURCE: University of Oxford, news release, May 22, 2014 HealthDay ...

361

Maintaining oral health across the life span.  

PubMed

: Oral health is directly related to systemic health, yet many Americans have limited to no access to dental health professionals. Nurse practitioners are in an excellent position to fill this void by providing caries risk assessments, chemical therapy to prevent progression of caries, and appropriate patient education to prevent caries. PMID:24841464

Jablonski, Rita; Mertz, Elizabeth; Featherstone, John D B; Fulmer, Terry

2014-06-15

362

Getting Serious Play: Life Span Career Education  

ERIC Educational Resources Information Center

Canada's $76.5 billion annual investment in education is paying dividends. A recent international survey ranked Canadian students "second" in reading literacy, "fifth" in mathematics and "fifth" in science. For nations and individuals alike, such mastery is intrinsic to success in the new knowledge economy. Yet, mastering these academic skills in…

Jarvis, Phil; Esbin, Howard

2006-01-01

363

The life span of the biosphere revisited  

NASA Technical Reports Server (NTRS)

How much longer the biosphere can survive on earth is reexamined using a more elaborate model than that of Lovelock and Whitfield (1982). The model includes a more accurate treatment of the greenhouse effect of CO2, a biologically mediated weathering parametrization, and the realization that C4 photosynthesis can persist to much lower concentrations of atmospheric CO2. It is found that a C4-plant-based biosphere could survive for at least another 0.9 Gyr to 1.5 Gyr after the present time, depending respectively on whether CO2 or temperature is the limiting factor. Within an additional 1 Gyr, earth may lose water to space, thereby following the path of Venus.

Caldeira, Ken; Kasting, James F.

1992-01-01

364

Life Span Personality Stability in Sibling Statuses.  

ERIC Educational Resources Information Center

Personality stability and change in sibling status in the one- and two-child-family are examined in this Study. Q-sort data were analyzed for the same 33 male and 34 female subjects during four periods of their lives-- early and late adolescence and early and middle adulthood. Results indicate that stability of personality was greatest during…

Rosenberg, B. G.

365

C-SPAN Classroom  

NSDL National Science Digital Library

The C-SPAN in the classroom website is geared toward teachers of political science - or specifically U.S. Government. The site is split into six segments: Principles of Government, the Constitution, Political Participation and each of the three branches of government. Each of these sections features video clips, and questions for class discussion. Free site membership is available, but not required to use the site. Some additional content and services are available with membership.

2006-11-25

366

Span efficiency in hawkmoths.  

PubMed

Flight in animals is the result of aerodynamic forces generated as flight muscles drive the wings through air. Aerial performance is therefore limited by the efficiency with which momentum is imparted to the air, a property that can be measured using modern techniques. We measured the induced flow fields around six hawkmoth species flying tethered in a wind tunnel to assess span efficiency, ei, and from these measurements, determined the morphological and kinematic characters that predict efficient flight. The species were selected to represent a range in wingspan from 40 to 110 mm (2.75 times) and in mass from 0.2 to 1.5 g (7.5 times) but they were similar in their overall shape and their ecology. From high spatio-temporal resolution quantitative wake images, we extracted time-resolved downwash distributions behind the hawkmoths, calculating instantaneous values of ei throughout the wingbeat cycle as well as multi-wingbeat averages. Span efficiency correlated positively with normalized lift and negatively with advance ratio. Average span efficiencies for the moths ranged from 0.31 to 0.60 showing that the standard generic value of 0.83 used in previous studies of animal flight is not a suitable approximation of aerodynamic performance in insects. PMID:23658113

Henningsson, Per; Bomphrey, Richard J

2013-07-01

367

Span efficiency in hawkmoths  

PubMed Central

Flight in animals is the result of aerodynamic forces generated as flight muscles drive the wings through air. Aerial performance is therefore limited by the efficiency with which momentum is imparted to the air, a property that can be measured using modern techniques. We measured the induced flow fields around six hawkmoth species flying tethered in a wind tunnel to assess span efficiency, ei, and from these measurements, determined the morphological and kinematic characters that predict efficient flight. The species were selected to represent a range in wingspan from 40 to 110 mm (2.75 times) and in mass from 0.2 to 1.5 g (7.5 times) but they were similar in their overall shape and their ecology. From high spatio-temporal resolution quantitative wake images, we extracted time-resolved downwash distributions behind the hawkmoths, calculating instantaneous values of ei throughout the wingbeat cycle as well as multi-wingbeat averages. Span efficiency correlated positively with normalized lift and negatively with advance ratio. Average span efficiencies for the moths ranged from 0.31 to 0.60 showing that the standard generic value of 0.83 used in previous studies of animal flight is not a suitable approximation of aerodynamic performance in insects.

Henningsson, Per; Bomphrey, Richard J.

2013-01-01

368

Phenotypic plasticity in reproductive traits: importance in the life history of Helix aspersa (Mollusca: Helicidae) in a recently colonized habitat  

Microsoft Academic Search

Reproductive traits of the land snail Helix aspersa Muller were investigated under artificial conditions from two samples, one collected from a population exposed to unpredictable human pressures in its natural environment, i.e. a recently created polders area with intensive agriculture, and the other from a snail farm in which animals were reared under constant conditions defined as 'optimal' for growth

LUC MADEC; CHRISTOPHE DESBUQUOIS; MARIE-AGNES COUTELLEC-VRETO

2000-01-01

369

A study of reproduction and other life cycle phenomena in planktonic protists using an acridine orange fluorescence technique  

Microsoft Academic Search

The percentage of dividing individuals and temporal reproductive patterns were determined for natural populations of several planktonic protists including five species of tintinnids, a dinoflagellate, and a diatom. To obtain these data, a method was used in which the nuclei of planktonic ciliates and phytoplankters can be fluorescently stained with acridine orange at the time of collection and fixation. The

D. W. Coats; J. F. Heinbokel

1982-01-01

370

Frequency-dependent reproductive success in female common lizards: a real-life hawk-dove-bully game?  

PubMed

Alternative strategies are characterised by context-dependent fitness payoffs, which means that their fitness depends on the frequency and the nature of their interactions with one or more strategies. The analysis of the variation of the fitness of each strategy in different social environments can elucidate the evolutionary dynamics played by the strategies. In the common lizard, three female colour types (yellow, orange and mixed) are associated with alternative reaction norms in reproduction and social behaviour that signal alternative strategies. To clarify the nature of colour-specific interactions and their influence on female fitness, we analysed the response of female reproductive success to an experimental manipulation of colour frequencies in natural populations. We found that juvenile body condition at birth for all colour types was negatively affected by the local frequency of yellow females. In addition, we found that mixed females had higher clutch hatching success in the populations where orange females were frequent. These results prove that female reproduction is sensitive to the social environment, and are consistent with a scenario of a hawk-dove-bully game, in which yellow females are aggressive hawks, orange females non-aggressive doves, and mixed females have a context-dependent bully strategy. In this system, the plastic bully strategy would confer a reproductive advantage to putative heterozygotes in some social environments, which could allow the maintenance of the system through context-dependent overdominance effects. PMID:19760272

Vercken, Elodie; Clobert, Jean; Sinervo, Barry

2010-01-01

371

Characteristics of an infinite life span diploid human fibroblast cell strain and a near-diploid strain arising from a clone of cells expressing a transfected v-myc oncogene  

SciTech Connect

Diploid human fibroblasts were transfected with a plasmid carrying a v-myc oncogene linked to the neo gene or with a vector control carrying a neo gene. Drug-resistant clones were isolated and subcultured as needed. All populations went into crisis and eventually senesced. But while they were senescing, viable-appearing clones were noted among the progeny of a transfected population that expressed the v-myc oncogene. After several months, these cells began replicating more rapidly. Karyotype analysis indicated that they were clonally derived since all of them had 45 chromosomes, including 2 marker chromosomes. This cell strain was designated MSU-1.1. Similar analysis showed that cells from an earlier passage were diploid. These cells were designated MSU-1.0. The expression of v-myc is probably required for acquisition of an infinite life span, since this phenotype did not develop in populations not expressing this oncogene. However, expression of v-myc is clearly not sufficient, since all of the progeny of the clone that gave rise to the MSU-1.0 cells expressed this oncogene, but the vast majority of them senesced.

Morgan, T.L.; Dajun Yang; Fry, D.G.; Hurlin, P.J.; Kohler, S.K.; Maher, V.M.; McCormick, J.J. (Michigan State Univ., East Lansing (United States))

1991-11-01

372

Differential reproductive strategies of two bivalves in the Dutch Wadden Sea  

NASA Astrophysics Data System (ADS)

Cerastoderma edule and Mya arenaria are two common bivalve species in European waters. Longevity and maximum size are much greater in the latter species. Because comparison of species life-history strategies states that a long life span (i.e. high annual survival) generally goes with lower fecundity, we hypothesise that reproductive output would be lower in M. arenaria than in C. edule. In the present paper, we studied the reproductive strategies of these two species in an intertidal and a subtidal area of the western Dutch Wadden Sea, by following seasonal changes in absolute and relative weights of somatic and gonadal tissues in these bivalves. Starting of spawning was similar in the two species, around May, except for intertidal M. arenaria, which initiated spawning in August. Individual energy investment in reproduction was similar for the two species but, unlike M. arenaria, C. edule spawned completely, releasing all energy of gonadal mass in the form of gametes. Mya arenaria used the gonad not only for reproduction but also for storage. In the intertidal area, we found a trade-off between longevity and reproduction, i.e. maximum reproductive output (expressed as a proportion of body mass) was higher in C. edule than in M. arenaria. However, since body size is larger and life span longer in M. arenaria than in C. edule, mean lifetime reproductive output per individual must be higher in the first than in the latter. Based on the differences in reproductive strategies of these two species, we hypothesise that the negative effects of warming climate on bivalve population dynamics in the Wadden Sea will be stronger in C. edule than in M. arenaria.

Cardoso, Joana F. M. F.; Witte, Johannes IJ.; van der Veer, Henk W.

2009-08-01

373

“Life is still going on”: Reproductive intentions among HIV-positive women and men in South Africa  

Microsoft Academic Search

This article reports on qualitative research investigating HIV positive individuals’ reproductive intentions and their influencing factors in Cape Town, South Africa.In-depth interviews were held with 61 HIV positive women and men; at the time of interview, half had been receiving antiretroviral treatment (ART) for over 6 months and half were not receiving ART.Being HIV positive modified but did not remove

Diane Cooper; Jane Harries; Landon Myer; Phyllis Orner; Hillary Bracken

2007-01-01

374

View of approach span and movable span, looking southeast from ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

View of approach span and movable span, looking southeast from navy land. Note that navigational channel exists only on north side of movable span. - Naval Supply Annex Stockton, Daggett Road Bridge, Daggett Road traversing Burns Cut Off, Stockton, San Joaquin County, CA

375

95. Reproduction from glass plate negative (Modjeski and Masters office, ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

95. Reproduction from glass plate negative (Modjeski and Masters office, Modjeski Collection, No. 150, January 18, 1908) SPANS 4 AND 5 - Burlington Northern Railroad Bridge, Spanning Willamette River at River Mile 6.9, Portland, Multnomah County, OR

376

89. Reproduction from glass plate negative (Modjeski and Masters office, ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

89. Reproduction from glass plate negative (Modjeski and Masters office, Modjeski Collection, No. 6, not dated) DRAW SPAN - Burlington Northern Railroad Bridge, Spanning Willamette River at River Mile 6.9, Portland, Multnomah County, OR

377

98. Reproduction from glass plate negative (Modjeski and Masters office, ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

98. Reproduction from glass plate negative (Modjeski and Masters office, Modjeski Collection, No. 181, May 5, 1908) STEEL ERECTION AT DRAW SPAN - Burlington Northern Railroad Bridge, Spanning Willamette River at River Mile 6.9, Portland, Multnomah County, OR

378

100. Reproduction from glass plate negative (Modjeski and Masters office, ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

100. Reproduction from glass plate negative (Modjeski and Masters office, Modjeski Collection, No. 198, July 25, 1908) VIEW OF DRAW SPAN - Burlington Northern Railroad Bridge, Spanning Willamette River at River Mile 6.9, Portland, Multnomah County, OR

379

Human Keratinocytes That Express hTERT and Also Bypass a p16INK4a-Enforced Mechanism That Limits Life Span Become Immortal yet Retain Normal Growth and Differentiation Characteristics  

PubMed Central

Normal human cells exhibit a limited replicative life span in culture, eventually arresting growth by a process termed senescence. Progressive telomere shortening appears to trigger senescence in normal human fibroblasts and retinal pigment epithelial cells, as ectopic expression of the telomerase catalytic subunit, hTERT, immortalizes these cell types directly. Telomerase expression alone is insufficient to enable certain other cell types to evade senescence, however. Such cells, including keratinocytes and mammary epithelial cells, appear to require loss of the pRB/p16INK4a cell cycle control mechanism in addition to hTERT expression to achieve immortality. To investigate the relationships among telomerase activity, cell cycle control, senescence, and differentiation, we expressed hTERT in two epithelial cell types, keratinocytes and mesothelial cells, and determined the effect on proliferation potential and on the function of cell-type-specific growth control and differentiation systems. Ectopic hTERT expression immortalized normal mesothelial cells and a premalignant, p16INK4a-negative keratinocyte line. In contrast, when four keratinocyte strains cultured from normal tissue were transduced to express hTERT, they were incompletely rescued from senescence. After reaching the population doubling limit of their parent cell strains, hTERT+ keratinocytes entered a slow growth phase of indefinite length, from which rare, rapidly dividing immortal cells emerged. These immortal cell lines frequently had sustained deletions of the CDK2NA/INK4A locus or otherwise were deficient in p16INK4a expression. They nevertheless typically retained other keratinocyte growth controls and differentiated normally in culture and in xenografts. Thus, keratinocyte replicative potential is limited by a p16INK4a-dependent mechanism, the activation of which can occur independent of telomere length. Abrogation of this mechanism together with telomerase expression immortalizes keratinocytes without affecting other major growth control or differentiation systems.

Dickson, Mark A.; Hahn, William C.; Ino, Yasushi; Ronfard, Vincent; Wu, Jenny Y.; Weinberg, Robert A.; Louis, David N.; Li, Frederick P.; Rheinwald, James G.

2000-01-01

380

Perceptual Span of Poor Readersa  

Microsoft Academic Search

A model is described attributing narrow perceptual spans of poor readers to abnormally slow phonological coding speed. In a test of the model with elementary-age school boys, (1) poor readers were slower than average readers on a digit naming task; (2) perceptual span for random digits was impaired for poor readers; (3) a linear relation was found between perceptual span

Carl Spring; Robert Farmer

1975-01-01

381

Changes in reproductive life-history strategies in response to nest density in a shell-brooding cichlid, Telmatochromis vittatus  

NASA Astrophysics Data System (ADS)

To determine whether the appearance of a reproductively parasitic tactic varies, and how this variation affects territorial males of the Lake Tanganyika cichlid fish Telmatochromis vittatus, we examined the reproductive ecology of territorial males in Mtondwe and compared it with that of a neighboring Wonzye population, where nest density differs from that at Mtondwe. In Wonzye, with high nest density, male tactics change with their body size from a territorial to a non-territorial parasitic tactic called piracy in which they conquer several nests defended by territorial males and take over the nests while females are spawning. These "pirate" males could decrease the costs incurred by travelling among nests by exclusively targeting aggregations of nests in close proximity while avoiding separate nests. Territorial males in Wonzye sacrifice the potential higher attractiveness offered by large nests and instead compete for nests farther from neighbors on which pirates less frequently intrude. In contrast, the Mtondwe population had lower nest density and piracy was absent. Given that the success of piracy depends on the close proximity of nests, nest density is likely responsible for the observed variation in the occurrence of piracy between the two populations. Furthermore, in Mtondwe, territorial males competed for larger nests and were smaller than the territorial males in Wonzye. Thus, this lower nest density may free territorial males from the selection pressures for increased size caused by both defense against nest piracy and the need to develop into pirates as they grow.

Ota, Kazutaka; Hori, Michio; Kohda, Masanori

2012-01-01

382

Changes in reproductive life-history strategies in response to nest density in a shell-brooding cichlid, Telmatochromis vittatus.  

PubMed

To determine whether the appearance of a reproductively parasitic tactic varies, and how this variation affects territorial males of the Lake Tanganyika cichlid fish Telmatochromis vittatus, we examined the reproductive ecology of territorial males in Mtondwe and compared it with that of a neighboring Wonzye population, where nest density differs from that at Mtondwe. In Wonzye, with high nest density, male tactics change with their body size from a territorial to a non-territorial parasitic tactic called piracy in which they conquer several nests defended by territorial males and take over the nests while females are spawning. These "pirate" males could decrease the costs incurred by travelling among nests by exclusively targeting aggregations of nests in close proximity while avoiding separate nests. Territorial males in Wonzye sacrifice the potential higher attractiveness offered by large nests and instead compete for nests farther from neighbors on which pirates less frequently intrude. In contrast, the Mtondwe population had lower nest density and piracy was absent. Given that the success of piracy depends on the close proximity of nests, nest density is likely responsible for the observed variation in the occurrence of piracy between the two populations. Furthermore, in Mtondwe, territorial males competed for larger nests and were smaller than the territorial males in Wonzye. Thus, this lower nest density may free territorial males from the selection pressures for increased size caused by both defense against nest piracy and the need to develop into pirates as they grow. PMID:22089034

Ota, Kazutaka; Hori, Michio; Kohda, Masanori

2012-01-01

383

Health-Related Quality of Life and Primi-Gravid: A Comparative Study of Natural Conception and Conception by Assisted Reproduction Technologies (ARTs)  

PubMed Central

Background Childbearing for the first time is a unique experience. Quality of life is an important indicator in health studies. This study aimed to assess the quality of life of women who were conceived by ARTs and had successful childbirth for the first time and to compare it with quality of life in women who become pregnant naturally and similarly had successful childbirth for the first time. Materials and Methods This was a cross sectional comparative study. The accessible sam- ple was recruited from patients attending an infertility clinic and two obstetric and gynecology clinics in Tehran, Iran, during March 2010 to March 2011. In all 276 patients were approached. Of these, 162 women (76 women in natural conception group and 86 women in assisted reproduction technologies group) who met the inclusion criteria were entered into the study. Quality of life was assessed using the 36-item Short Form Health Survey (SF-36). Women completed the questionnaire at two time points: i. last trimester and ii. first month after delivery. Comparison was made between two groups using Mann-Whitney U test and paired samples t test. Results Comparing the SF-36 scores between women in natural conception group and ARTs group before childbirth, it was found that natural group had better condition on physical functioning, role limitation due to physical problems, bodily pain and social functioning, while the ARTs group reported better status on general health, vitality, role limitation due to emotional problems, and mental health. However, after childbirth, the ARTs group reported a better condition almost on all measures, except for physical functioning. Comparing differences in obtained scores between two groups before and after childbirth, the results showed that improvements in health related quality of life measures for the ARTs group were greater in all measures, expect for general health. Conclusion The findings from this study suggest that health-related quality of life was improved in women who became a mother for the first time by either method. Comparing to women who became mother by natural conception, women who received ARTs showed better quality of life from this first successful experience.

Ahmadi, Seyed Ebrahim; Montazeri, Ali; Mozafari, Ramin; Azari, Afsaneh; Nateghi, Mohammad Reza; Ashrafi, Mahnaz

2014-01-01

384

Life history trade-offs and phenotypic plasticity in the reproduction of Galápagos lava lizards ( Microlophus delanonis )  

Microsoft Academic Search

Trade-offs between traits are a fundamental component of life history theory. However, because individuals may differ in the amount of energy available for allocation between traits, expected negative relationships are often difficult to detect or may become positive. The latter can occur when both traits are phenotypically plastic in response to variation in environmental productivity. We tested this hypothesis by

Mark A. Jordan; Howard L. Snell

2002-01-01

385

Life.  

National Technical Information Service (NTIS)

Discusses the general characteristics of life as we know it. Uses a number of examples to show how life has adapted to earth conditions and certain life forms can withstand environmental shocks. Describes the conditions on Mars with the question raised as...

1994-01-01

386

Life history strategies in zooplankton communities: The significance of female gonad morphology and maturation types for the reproductive biology of marine calanoid copepods  

NASA Astrophysics Data System (ADS)

The present review addresses the reproductive strategies of marine calanoid copepods, as affected by their physiological preconditioning, and aims to enhance understanding of their adaptations to specific environmental conditions. Knowledge about oocyte development and internal gonad structure, especially in relation to feeding conditions, is essential for a complete understanding of the reproductive strategies of the copepods. Therefore, the foci of the review are to identify general patterns in oocyte and gonad development in calanoid copepod species from marine ecosystems worldwide and to elucidate the significance of gonad structures for reproductive strategies. Oogenesis is similar in all copepod species. During maturation, the morphology of the oocytes changes distinctly and, according to oocyte size and appearance of ooplasm and nucleus, five oocyte developmental stages are distinguished. In contrast, the gonad structure and its changes during the spawning cycle differ considerably among species, and these differences are related to specific reproductive traits. Four gonad morphology types can be distinguished: the Calanus-type, found in species from all over the world with distinctly different life history traits, is apparently most common in calanoid copepods. In this gonad type, most oocyte developmental stages are present simultaneously, and usually many oocytes mature synchronously, all of which are released in one clutch. The gonad structure allows frequent spawning and large clutches, hence, high egg production rates. This may be a preconditioning for exploiting seasonally high food supply. However, the Calanus-type was also found in species producing eggs at lower rates. In the diverticula of Pseudocalanus-type gonads, only two oocyte developmental stages are present and usually fewer oocytes mature synchronously. Accordingly, the egg production rate is generally lower as compared to the Calanus-type, and apparently only this gonad-type is structurally suitable for ovigerity. Species with Pseudocalanus-type gonads are present from polar seas to the tropics, some of them being key species. The Acartia-type was scarce, found in only one species, Acartia clausi. Here all oocyte developmental stages are present, including intermediate stages, but only a few oocytes mature synchronously and are released together. High spawning frequency compensates for the small clutches, and hence egg production rate may be as high as in Calanus-type gonads. In the Aetidius-type gonad, the total number of oocytes in the diverticula is low as is the number of oocytes maturing synchronously. Less is known about the reproductive biology of species with Aetidius-type gonads; however, their distribution and feeding patterns suggest that this type is common in species inhabiting environments of low food availability. The differences in gonad structures also lead to differences in the egg size:female size ratio, as the space available for each mature oocyte depends on the total number of oocytes. Independent from gonad-type, the eggs are relatively large in species in which the gonads contain only few oocytes, whereas small eggs are produced by species with gonads filled with many oocytes. Since all species carrying their eggs in external sacs until hatching (ovigerous species) have Pseudocalanus-type gonads, the scatter in their egg size:female size ratio is low. The broadcast spawning species are of all gonad-types, and consequently the scatter among them is high. A major factor affecting the timing and magnitude of spawning of calanoid copepods is the energy supply for gonad development. Therefore, part of the review elucidates the role of internal and external resources in fuelling egg production. In many species, freshly assimilated food is transferred into egg material within a short period of time, and clutch size and spawning frequency are the two parameters that allow adjustment of egg production to food availability and temperature. However, internal body reserves may also fuel oocyte development. The extent to which oogene

Niehoff, Barbara

2007-07-01

387

Orderly Spanning Trees with Applications  

Microsoft Academic Search

We introduce and study orderly spanning trees of plane graphs. This algorithmic tool generalizes canonical orderings, which exist only for triconnected plane graphs. Although not every plane graph admits an orderly spanning tree, we provide an algorithm to compute an orderly pair for any connected planar graph G, consisting of an embedded planar graph H isomorphic to G, and an

Yi-Ting Chiang; Ching-Chi Lin; Hsueh-I Lu

2001-01-01

388

Individual Differences in Memory Span.  

National Technical Information Service (NTIS)

One series of experiments examined the correlation between memory span and the speed of symbol manipulation in short-term memory, and another experiment analyzed the effects of extended practice on memory span. In the first study, most of the estimates of...

W. G. Chase D. R. Lyon K. A. Ericsson

1979-01-01

389

Nursing Process. Nursing: Basic Needs I. Nursing: Basic Needs II. Nursing through the Life Span. Entry into Professional Nursing. A Basic Course Outline (College Freshmen) for Nursing. A Four Year "2+2" Articulated Curriculum for the Occupation of Nursing.  

ERIC Educational Resources Information Center

This course outline provides materials for third-year courses in a "2+2" curriculum for the occupation of registered nurse. It is part of a planned and articulated 4-year curriculum that spans the junior and senior years of high school and the freshman and sophomore years of the postsecondary institution. Introductory materials include: the…

Maddox, Gaylon; And Others

390

The politics of reproduction.  

PubMed

The topic of human reproduction encompasses events throughout the human and especially female life-cycle as well as ideas and practices surrounding fertility, birth, and child care. Most of the scholarship on the subject, up through the 1960s, was based on cross-cultural surveys focused on the beliefs, norms, and values surrounding reproductive behaviors. Multiple methodologies and subspecialties, and fields like social history, human biology, and demography were utilized for the analysis. The concept of the politics of reproduction synthesizes local and global perspectives. The themes investigated include: the concept of reproduction, population control, and the internationalization of state and market interests (new reproductive technologies); social movements and contested domains; medicalization and its discontents; fertility and its control; adolescence and teen pregnancy; birth; birth attendants; the construction of infancy and the politics of child survival; rethinking the demographic transition; networks of nurturance; and meanings of menopause. The medicalization of reproduction is a central issue of studies of birth, midwifery, infertility, and reproductive technologies. Scholars have also analyzed different parts of the female life-cycle as medical problems. Other issues worth analysis include the internationalization of adoption and child care workers; the crisis of infertility of low-income and minority women who are not candidates for expensive reproductive technologies; the concerns of women at high risk for HIV whose cultural status depends on their fertility; questions of reproduction concerning, lesbians and gay men (artificial insemination and discrimination in child rearing); the study of menopause; and fatherhood. New discourse analysis is used to analyze state eugenic policies; conflicts over Western neocolonial influences in which women's status as childbearers represent nationalist interests; fundamentalist attacks on abortion rights; and the AIDS crisis. PMID:12288961

Ginsburg, F; Rapp, R

1991-01-01

391

Reproductive Hazards  

MedlinePLUS

... and female reproductive systems play a role in pregnancy. Problems with these systems can affect fertility and ... a reproductive hazard can cause different effects during pregnancy, depending on when she is exposed. During the ...

392

Aspects of reproduction, early life history, and biology of macrourid fishes off Oregon, U.S.A.  

NASA Astrophysics Data System (ADS)

Egg sizes, fecundities, times of spawning, early benthic life, size frequency, and distribution by sex and size are described for some of the four most common macrourid species off Oregon: Coryphaenoides acrolepis, C. armatus, C. filifer and C. leptolepis. Sizes of eggs at comparable developmental stages from different species were quite different. Average fecundities ranged about 26,000 to 2,500,000 eggs. C. acrolepis and C. filifer may spawn semi-annually. Juveniles of the three sympatric species, C. armatus, C. filifer, and C. leptolepis, become benthic in habit at different sizes. Different mouth size of each species may minimize competition for food. Size frequency distributions were either unimodal ( C. filifer, C. armatus) or bimodal ( C. acrolepis, C. leptolepis). However, small C. filifer were rarely collected suggesting that they remain pelagic longer than the young of other species. C. armatus and C. leptolepis were 'bigger-deeper', but the trend was not evident in the other two species. Sex ratios also differed: male C. armatus and C. leptolepis were less abundant than females, although their proportion increased with distance offshore. Numbers of males and females were about equal in C. acrolepis and C. filifer. Little evidence for the existence of sexual segregation was found. The liver apparently serves as a buoyancy mechanism in large C. armatus.

Stein, David L.; Pearcy, William G.

1982-11-01

393

Animal Reproduction  

NSDL National Science Digital Library

From Dr. Michael Gregory of Clinton Community College, this site is a concise overview of animal reproduction. The site addresses important aspects of sexual and asexual reproduction, the male and female reproductive systems, fertilization, and the importance of hormones. Visitors to the site will find diagrams outlining biological processes especially helpful.

Gregory, Michael

2007-12-14

394

Tradeoffs in basal area growth and reproduction shift over the lifetime of a long-lived tropical species.  

PubMed

Understanding of the extent to which reproductive costs drive growth largely derives from reproductively mature temperate trees in masting and non-masting years. We modeled basal area increment (BAI) and explored current growth-reproduction tradeoffs and changes in such allocation over the life span of a long-lived, non-masting tropical tree. We integrated rainfall and soil variables with data from 190 Bertholletia excelsa trees of different diameter at breast height (DBH) sizes, crown characteristics, and liana loads, quantifying BAI and reproductive output over 4 and 6 years, respectively. While rainfall explains BAI in all models, regardless of DBH class or ontogenic stage, light (based on canopy position and crown form) is most critical in the juvenile (5 cm ? DBH < 50 cm) phase. Suppressed trees are only present as juveniles and grow ten times slower (1.45 ± 2.73 m(2) year(-1)) than trees in dominant and co-dominant positions (13.25 ± 0.82 and 12.90 ± 1.35 m(2) year(-1), respectively). Additionally, few juvenile trees are reproductive, and those that are, demonstrate reduced growth, as do reproductive trees in the next 50 to 100 cm DBH class, suggesting growth-reproduction tradeoffs. Upon reaching the canopy, however, and attaining a sizeable girth, this pattern gradually shifts to one where BAI and reproduction are influenced independently by variables such as liana load, crown size and soil properties. At this stage, BAI is largely unaffected by fruit production levels. Thus, while growth-reproduction tradeoffs clearly exist during early life stages, effects of reproductive allocation diminish as B. excelsa increases in size and maturity. PMID:23404069

Staudhammer, Christina L; Wadt, Lúcia H O; Kainer, Karen A

2013-09-01

395

Evolutionary optimization of life-history traits in the sea beet Beta vulgaris subsp. maritima: Comparing model to data  

NASA Astrophysics Data System (ADS)

At evolutionary equilibrium, ecological factors will determine the optimal combination of life-history trait values of an organism. This optimum can be assessed by assuming that the species maximizes some criterion of fitness such as the Malthusian coefficient or lifetime reproductive success depending on the degree of density-dependence. We investigated the impact of the amount of resources and habitat stability on a plant's age at maturity and life span by using an evolutionary optimization model in combination with empirical data. We conducted this study on sea beet, Beta vulgaris subsp. maritima, because of its large variation in life span and age at first reproduction along a latitudinal gradient including considerable ecological variation. We also compared the consequence in our evolutionary model of maximizing either the Malthusian coefficient or the lifetime reproductive success. Both the data analysis and the results of evolutionary modeling pointed to habitat disturbance and resources like length of the growing season as factors negatively related to life span and age at maturity in sea beet. Resource availability had a negative theoretical influence with the Malthusian coefficient as the chosen optimality criterion, while there was no influence in the case of lifetime reproductive success. As suggested by previous theoretical work the final conclusion on what criterion is more adequate depends on the assumptions of how in reality density-dependence restrains population growth. In our case of sea beet data R0 seems to be less appropriate than ?.

Hautekèete, N.-C.; Van Dijk, H.; Piquot, Y.; Teriokhin, A.

2009-01-01

396

CICLO DE VIDA Y TASAS DE SUPERVIVENCIA Y REPRODUCCIÓN DE Copitarsia incommoda WALKER (LEPIDOPTERA: NOCTUIDAE) EN TRES CULTIVARES DE Brassica oleracea L. LIFE CYCLE AND SURVIVAL AND REPRODUCTION RATES OF Copitarsia incommoda WALKER (LEPIDOPTERA: NOCTUIDAE) IN THREE CULTIVARS OF Brassica oleracea L  

Microsoft Academic Search

This research was carried out to know the biological cycle and the survival and reproduction rates of Copitarsia incommoda, previously known as Copitarsia consueta (Walker) (Angulo and Olivares, 2003), in three different cultivars of Brassica oleracea L., crops on which this species feeds. For this purpose, the demographic technique of life and reproduction tables was used. The study allowed to

Leonardo Flores-Pérez; Néstor Bautista-Martínez; Jorge Vera-Graziano; Jorge Valdez-Carrasco; Andrés O. Angulo; Especialidad en Entomología

397

Animal Reproduction  

NSDL National Science Digital Library

This Topic in Depth takes a look at organizations and educational websites concerned with reproduction in humans and other animals. The Society for the Study of Reproduction (SSR) "is an association of scientists and physicians interested in research in reproduction. Some members are engaged in basic or applied research, while others perform clinical practice." The SSR website (1) contains downloadable copies of the SSR Newsletter; position statements; and information about meetings, awards, and the organization. The Society for Reproduction and Fertility (SRF) "is open to scientists and students worldwide, who work on any aspect of reproductive biology or fertility in man and animals." The SRF website (2) contains sections regarding News, Events, Jobs, Honours, and Grants. SRF makes downloadable copies of its newsletter available as well. The primary aim of the European Society of Human Reproduction & Embryology (ESHRE) "is to promote interest in, and understanding of, reproductive biology and medicine. It does this through facilitating research and subsequent dissemination of research findings in human reproduction and embryology to the general public, scientists, clinicians and patient associations; it also works to inform politicians and policy makers throughout Europe." The ESHRE site (3) contains information about activities, membership, publications, special interest groups, and jobs. The primary function of the Centre for Reproductive Biology in Uppsala (CRU) "is to increase the knowledge about reproduction in animals and humans by applying a more comprehensive view on reproductive biology." CRU is composed of scientists from both Uppsala University and the Swedish University of Agricultural Science. The CRU site (4) contains information about a number of publications, and contact information for CRU members. The Population Council is a nonprofit "organization that conducts biomedical, social science, and public health research." The "Council's reproductive biology and immunology program undertakes fundamental research in the reproductive sciences and immunological processes related to sexually transmitted infections, particularly HIV." This website (5) provides information about different aspects of the research program including Germ Cell Dynamics, Sperm Maturation, and Physiology of Sertoli Cells. From Dr. Michael Gregory of Clinton Community College, the next site (6) is a concise overview of animal reproduction which addresses important aspects of sexual reproduction, and male and female reproductive systems. The final site (7) contains lecture notes regarding avian reproduction from Dr. Gary Ritchison's Ornithology course at Eastern Kentucky University. The lecture notes are interspersed with some especially nice images and diagrams.

398

Temporal variability in the life history and reproductive biology of female dugongs in Torres Strait: The likely role of sea grass dieback  

NASA Astrophysics Data System (ADS)

The extensive sea grass meadows in Torres Strait enable it to be a globally important habitat for the dugong, Dugong dugon, a marine mammal of cultural and dietary significance to Torres Strait Islanders and the basis for the substantial island-based fishery in the Torres Strait Protected Zone. Torres Strait sea grass communities are subjected to episodic diebacks which are now believed to be largely natural events. Information on dugong life history was obtained from specimens obtained from female dugongs as they were butchered for food by Indigenous hunters at two major dugong hunting communities in Torres Strait: Daru (9.04°S, 143.21°E) in 1978-1982 (a time of sea grass dieback and recovery) and Mabuiag Island (9.95°S, 142.15°E) in 1997-1999 (when sea grasses were abundant). Dugongs sampled in 1997-1999 had their first calf at younger ages (minimum of 6 cf. 10 years), and more frequently (interbirth interval based on all possible pregnancies 2.6±0.4 (S.E.) yr cf. 5.8±1.0 yr) than the dugongs sampled in 1978-1982. Pregnancy rates increased monotonically during 1978-1982, coincident with sea grass recovery. The age distribution of the female dugongs collected in 1997-1999 also suggested a low birth rate between 1973 and 1983 and/or or a high level of mortality for animals born during this period. These results add to the evidence from other regions that the life history and reproductive rate of female dugongs are adversely affected by sea grass loss, the effect of which cannot be separated from a possible density-dependent response to changes in dugong population size. Many green turtles in Torres Strait were also in poor body condition coincident with the 1970s sea grass dieback. The impacts of future sea grass diebacks need to be anticipated when management options for the traditional Torres Strait fisheries for dugongs and green turtles are evaluated.

Marsh, Helene; Kwan, Donna

2008-09-01

399

SPAN: Special Peer Action Network.  

ERIC Educational Resources Information Center

The Special Peer Action Network (SPAN) program in Jackson County (Florida) schools brings together gifted students and students with developmental disabilities. Gifted students received background information and training in how to serve as models, helpers, and friends of students with disabilities and then participated in structured interactions…

Plumb, Inia Jean; Brown, Drucilla C.

1990-01-01

400

Effects of reproduction on immuno-suppression and oxidative damage, and hence support or otherwise for their roles as mechanisms underpinning life history trade-offs, are tissue and assay dependent.  

PubMed

Life history parameters appear to be traded off against each other, but the physiological mechanisms involved remain unclear. One hypothesis is that potentially energetically costly processes such as immune function and protection from oxidative stress may be compromised during reproductive attempts because of selective resource allocation. Lower temperatures also impose energy costs, and hence allocation decisions might be more pronounced when animals are forced to reproduce in the cold. Here, we experimentally tested whether reproduction at different ambient temperatures was associated with elevated oxidative stress and suppressed immune function in Mongolian gerbils (Meriones unguiculatus). Using a variety of different markers for both immune function and oxidative stress, we found that some measures of immune function (serum bactericidal capacity and size of the thymus) were significantly suppressed, while some measures of oxidative protection [serum superoxide dismutase (SOD) activity and glutathione peroxidase (GPx) activity] were also reduced, and a marker of oxidative damage (protein carbonyls in serum) was increased in lactating compared with non-reproductive gerbils. These changes were in line with the selective resource allocation predictions. However, the phytohaemagglutinin response and serum total immunoglobulin (IgG) were not suppressed, and other markers of oxidative damage [malondialdehyde (MDA) (TBARS) and protein carbonyls in the liver] were actually lower in lactating compared with non-reproductive gerbils, consistent with increased levels of SOD activity and total antioxidant capacity in the liver. These latter changes were opposite of the expectations based on resource allocation. Furthermore, other measures of protection (GPx levels in the liver and protein thiols in both serum and liver) and damage [MDA (TBARS) in serum] were unrelated to reproductive status. Ambient temperature differences did not impact on these patterns. Collectively, our results indicated that the inferred effects of reproduction on immunosuppression and oxidative damage, and hence support or otherwise for particular physiological mechanisms that underpin life history trade-offs, are critically dependent on the exact markers and tissues used. This may be because during reproduction individuals selectively allocate protection to some key tissues, but sacrifice protection of others. PMID:23997195

Yang, Deng-Bao; Xu, Yan-Chao; Wang, De-Hua; Speakman, John R

2013-11-15

401

Reproductive governance in Latin America.  

PubMed

This paper develops the concept of reproductive governance as an analytic tool for tracing the shifting political rationalities of population and reproduction. As advanced here, the concept of reproductive governance refers to the mechanisms through which different historical configurations of actors - such as state, religious, and international financial institutions, NGOs, and social movements - use legislative controls, economic inducements, moral injunctions, direct coercion, and ethical incitements to produce, monitor, and control reproductive behaviours and population practices. Examples are drawn from Latin America, where reproductive governance is undergoing a dramatic transformation as public policy conversations are coalescing around new moral regimes and rights-based actors through debates about abortion, emergency contraception, sterilisation, migration, and assisted reproductive technologies. Reproductive discourses are increasingly framed through morality and contestations over 'rights', where rights-bearing citizens are pitted against each other in claiming reproductive, sexual, indigenous, and natural rights, as well as the 'right to life' of the unborn. The concept of reproductive governance can be applied to other settings in order to understand shifting political rationalities within the domain of reproduction. PMID:22889430

Morgan, Lynn M; Roberts, Elizabeth F S

2012-01-01

402

âÂÂThe Calamity of So Long LifeâÂÂ: Life Histories, Contaminants, and Potential Emerging Threats to Long-lived Vertebrates  

NSDL National Science Digital Library

Persistent contaminants are ubiquitous in the environment, often present at concentrations that may jeopardize reproductive fitness only after long periods of exposure. As the duration of exposure is largely regulated by life span, long-lived species of high trophic status, such as many reptiles, birds, and mammals, may be at risk of reduced fitness and population decline. Delayed maturation and iteroparity confer the potential for cumulative effects to be expressed prior to reproduction, and large parental investments in yolk and milk may threaten offspring because of exposure during critical developmental periods. Long generation times may delay emergence of obvious effects on populations, perhaps eluding early intervention, while constraining rates at which populations may recover if conditions subsequently improve. Life history theory thus suggests that the suite of traits that optimized reproductive fitness throughout long-lived species' evolutionary histories may ultimately put them in peril in the modern, anthropogenically altered environment.

Christopher L. Rowe (University of Maryland;)

2008-08-01

403

Exploring the Dimensionality of Digit Span  

ERIC Educational Resources Information Center

The Digit Span subtest from the Wechsler Scales is used to measure Freedom from Distractibility or Working Memory. Some published research suggests that Digit Span forward should be interpreted differently from Digit Span backward. The present study explored the dimensionality of the Wechsler Memory Scale-III Digit Span (forward and backward)…

Bowden, Stephen C.; Petrauskas, Vilija M.; Bardenhagen, Fiona J.; Meade, Catherine E.; Simpson, Leonie C.

2013-01-01

404

THE DISCOUNTED REPRODUCTIVE NUMBER FOR EPIDEMIOLOGY  

PubMed Central

The basic reproductive number, , and the effective reproductive number, , are commonly used in mathematical epidemiology as summary statistics for the size and controllability of epidemics. However, these commonly used reproductive numbers can be misleading when applied to predict pathogen evolution because they do not incorporate the impact of the timing of events in the life-history cycle of the pathogen. To study evolution problems where the host population size is changing, measures like the ultimate proliferation rate must be used. A third measure of reproductive success, which combines properties of both the basic reproductive number and the ultimate proliferation rate, is the discounted reproductive number . The discounted reproductive number is a measure of reproductive success that is an individual’s expected lifetime offspring production discounted by the background population growth rate. Here, we draw attention to the discounted reproductive number by providing an explicit definition and a systematic application framework. We describe how the discounted reproductive number overcomes the limitations of both the standard reproductive numbers and proliferation rates, and show that is closely connected to Fisher’s reproductive values for different life-history stages

Reluga, Timothy C.; Medlock, Jan; Galvani, Alison

2013-01-01

405

92. Reproduction from glass plate negative (Modjeski and Masters office, ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

92. Reproduction from glass plate negative (Modjeski and Masters office, Modjeski Collection No. 70, December 24, 1906) CAISSON No. 2 - Burlington Northern Railroad Bridge, Spanning Willamette River at River Mile 6.9, Portland, Multnomah County, OR

406

91. Reproduction from glass plate negative (Modjeski and Masters office, ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

91. Reproduction from glass plate negative (Modjeski and Masters office, Modjeski Collection, No. 44, October 13, 1906) SANDBAGGING PIER No. 4 - Burlington Northern Railroad Bridge, Spanning Willamette River at River Mile 6.9, Portland, Multnomah County, OR

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