摘要:

Some of the biochemical components of the skin of the garden lizard, Calotes versicolor, have been analyzed in relation to age. The DNA content was found to decrease sharply during the rapid growth phase and again between the fully matured and older group. The RNA content reached its peak at the fully matured stage, followed by a decline. The RNA/DNA and RNA/protein ratio showed the same trend. A sharp decline in protein content was recorded during the rapid growth phase. Protein content, expressed on the basis of DNA, showed the same trend. An increase in protein content was found between the sexually matured stage and the older group. The free amino acid level did not show significant age-related change. During the period between the rapid growth phase and sexual maturity the water content of the skin showed a significant increase and remained almost constant thereafter.

ISSN:0304-324X    

DOI:10.1159/000211992

出版商:S. Karger AG    

年代:1974

数据来源: Karger

摘要:

A deficiency of spontaneous regeneration is a characteristic feature in many chronic pathological skin processes. However, if a degree of vitality of the cells is still present, it is possible to release their inhibited embryonic properties, so that they behave like normal cells, contributing to the restoration of the original tissue architecture and function. The study reported here was performed on the skin of aged human beings and on arterial walls of old dogs and confirmed to a certain extent previous experience.

ISSN:0304-324X    

DOI:10.1159/000211993

出版商:S. Karger AG    

年代:1974

数据来源: Karger

摘要:

Total brain DNA, protein, wet and dry weight, and total number of nuclei were measured in animals from a colony of ageing C57BL mice. No significant differences were found in a series of animals from 4 to 158 weeks old.

ISSN:0304-324X    

DOI:10.1159/000211994

出版商:S. Karger AG    

年代:1974

数据来源: Karger

摘要:

Hypophysectomy abolishes the activity of amine (lysyl) oxidase in rat aorta, and this is associated with a reduced aldehyde content of soluble collagen in tail tendon. Both amine oxidase activity and the aldehyde content decrease with age. Treatment of the hypophysectomized rat with either cortisone or growth hormone restores the activity of amine (lysyl) oxidase. This work supports the hypothesis that hypophysectomy inhibits collagen aging (cross-linkage) by reducing the activity of lysyl oxidase, the enzyme concerned in the first step of cross-linkage.

ISSN:0304-324X    

DOI:10.1159/000211995

出版商:S. Karger AG    

年代:1974

数据来源: Karger

摘要:

Biological age was assessed in a methodological field study in two unselected Finnish populations which comprised 460 males aged 25–27, 35–37, 45–47 and 55–57 years. The test battery consisted of six tests which had the following correlations to chronological age: threshold for vibratory stimuli in ankle (0.624), digit symbol test (––0.588), vital capacity (––0.594), audiometry at 4,000 cps (0.563), simple reaction time (0.329), and index of cortical thickness of metacarpal bone (––0.299). Multiple correlations to chronological age ranged between 0.744 and 0.831, depending on the variables included in the index. The length of education, occupation and district of living explained partly the variation i

ISSN:0304-324X    

DOI:10.1159/000211996

出版商:S. Karger AG    

年代:1974

数据来源: Karger

摘要:

Male rats of 90, 150, 300, 450 or 600 days of age were placed into sedentary or physical training experimental groups. Experimental animals ran daily for 20 min at 10–20 m/min on a treadmill set at an 8-degree incline. The experimental period lasted at least 300 days. Surviving rats from each group were chosen randomly and sacrificed at 150-day intervals up to 1,050 days of age. Muscle and organ weights were analyzed by grouping animals according to their age at death and also according to their age at the initiation of the training program. Muscle and organ weight data suggest that training has a minimal affect on rats past a threshold age (approximately 450 days of age), and initiation of a training program at a late age (approximately 600 days of age) may adversely affect the rat. When the effects of age and training are combined, those attributable to age seem to be more important, supporting the view that there is a threshold age beyond which the initiation of a training program no longer affects the muscle and organ weight

ISSN:0304-324X    

DOI:10.1159/000211997

出版商:S. Karger AG    

年代:1974

数据来源: Karger

摘要:

The effect of ageing on growth, function and cell loss in differentiated cells is reviewed briefly. Although there is some evidence of loss of function and of delay in the initiation of cell division in ageing cells, there is no evidence of massive cell loss. It is unlikely that an overall loss of cells or cell malfunction is responsible for limitation of total life-span of an individual. Although there seems to be a programmed life-span for some cells analogous to the 40–50 cell division cycles found in some tissue culture experiments, few normal mammalian cells undergo their total possible number of cell divisions. It is suggested that most of the widely varied age-associated changes which are found are due to random damage and that the total possible life-span of the individual may be controlled by small groups of essential cells in specific organs and tissues. The life-span of these cells could be programmed during development as part of the normal process of differentiatio

ISSN:0304-324X    

DOI:10.1159/000211998

出版商:S. Karger AG    

年代:1974

数据来源: Karger

ISSN:0304-324X    

DOI:10.1159/000211999

出版商:S. Karger AG    

年代:1974

数据来源: Karger

ISSN:0304-324X    

DOI:10.1159/000212000

出版商:S. Karger AG    

年代:1974

数据来源: Karger

ISSN:0304-324X    

DOI:10.1159/000212001

出版商:S. Karger AG    

年代:1974

数据来源: Karger