BACKGROUND Transgenic mice with low levels of global insulin-like growth factor-I (IGF-I) throughout their life span, including pre- and postnatal development, have increased longevity. This study investigated whether specific deficiency of liver-derived, endocrine IGF-I is of importance for life span. METHODS AND FINDINGS Serum IGF-I was reduced by approximately 80% in mice with adult, liver...

aging and disease in a number of model systems , including primates (Colman et al., 2009). However, the underlying mechanisms by which CR affects mammalian life span remain unclear. In lower organisms, a number of potential mechanisms have been postulated to regulate life span. Included in these are the insulin and insulin-like growth factor (IGF-1) signaling (IIS) pathways and the mammalian ta...

1. Longitudinal studies of various vertebrate populations have recently demonstrated senescent declines in reproductive performance and/or survival probability with age to be almost ubiquitous in nature. Little is known, however, about the extent to which rates of senescence vary between individuals, and about causes or consequences of such variation. Quantifying these links in natural populati...

this study was conducted to evaluate a temperature regime ranged from 15 to 30°c on survival, growth, life span and reproductive traits (reproductive period, clutch number, offspring number) of phallocryptus spinosa from iran. newly hatched nauplii (n= 200 and 3 replicates per each treatment) were allocated into containers and maintained at various temperature regimes (at 15, 20, 25 and 30˚c). ...

Ovarian development, oviposition, larval eclosion, ornithine decarboxylase (ODC) activity, ovarian, testis and ejaculatory apodeme measurements (length, width, and area), and the number of spermatozoa of Anastrepha fraterculus (Wiedemann) were analyzed at alternating (20 degrees/6 degrees C and 20 degrees/13 degrees C) and constant (6 degrees C; 25 degrees C) temperatures. Life span and life ex...

The hematopoietic system is maintained throughout adult life by a population of immature precursors known as the multipotential stem cells . These stem cells are unique within the system in that they have the capacity to generate progeny of all the blood cell lineages, as well as the capacity to generate cells with a potential similar to their own, a characteristic often referred to as self-ren...

A conceptualization of coping and adaptation following victimization is presented from a life-span developmental perspective. Recovery is characterized as an evolving process of interaction among three dimensions: social cognition, environmental sensitivity, and emotional-behavioral functioning. The model is illustrated through an individual case study and through an approach to research on out...

There is a need for aging theories to become holistic and multidisciplinary with a life span focus. A theory is the construction of explicit explanations in accounting for empirical findings. A good gerontological theory integrates knowledge, tells how and why phenomena are related, leads to prediction, and provides process and understanding. In addition, a good theory must be holistic and take...