Influence of age on circadian rhythms of adrenoceptors in brain cortex, heart and submandibular glands of BALB/c mice: when circadian studies are not only useful but necessary.

In the present paper we study circadian rhythm variation of alpha1-adrenoceptors (alpha(1)ARs) and beta-adrenoceptors (betaARs) characteristics during aging. Experiments have been performed on mice's whole brain cortex, heart and submandibular glands, which have physiologically relevant regulatory functions at different ages. We used 36 young (4 months) and 36 old (26 months) mice; six animals from each group were sacrificed every 4h, starting at 8.

Mathematical modeling of the aging processes and the mechanisms of mortality: paramount role of heterogeneity.

Main problems of modeling the link between aging processes and mechanisms of mortality are addressed. Various applications of Gompertz's law, which allowed to formulate some fruitful hypotheses on the field, are reviewed. Some pitfalls occurring in its applications are also discussed using a model built on purpose to overcome these difficulties.

Gut neuroendocrine cells: relationship to the proliferative activity and apoptosis of mucous epitheliocytes in aging.

Objectives: Diffuse neuroendocrine system (DNES) cells regulate homeostasis via neurocrine, endocrine and paracrine mechanisms. Extensive effects of peptide hormones and biogenic amines necessitate studying of DNES cell biology in aging. In this connection, the functional morphology of gut neuroendocrine cells (NEC), proliferative activity and apoptosis of mucous epithelial cells in aging have been studied.

Use of mathematical models of survivorship in the study of biomarkers of aging: the role of heterogeneity.

An ever increasing number of people have been engaging in aging research using various interventions aimed to modify aging processes, and/or life span, of experimental animals. Since this type of studies needs outcome parameters for assessing the efficacy of such interventions, research on biomarkers of aging (ABs) has received new stimuli. In the present paper, the problem of the occurrence of a vicious circle any time we study ABs and determinants of aging is addressed.