摘要:

The activities of four lysosomal acid hydrolases (LAH) in the lungs of two strains of mice changed significantly throughout the life cycle. In the C57B1/6J animals, acid phosphatase (AP) and β-glucuronidase (β-G) were maximally active during early neonatal life then gradually declined to the adult levels by 4–5 weeks of age. After reaching the adult level, acid phosphatase activities did not change significantly through 20 months of age. In contrast, β-G activities increased markedly with advanced age. N-Acetyl-β-D-glucosaminidase (GAD) activities did not change significantly during late fetal, neonatal or young adult stages but increased significantly with advancing age. In the lungs of the CFW animals, the increase in activities of β-G and GAD between young adult life and advanced age was highly significant, whereas there was no notable change in the activities of acid phosphatase or arylsul-fatase (AS). The specific activities of the hydrolases in the lungs of the C57B1/6J strain were quite similar to those in the lungs of the CFW strain. The activities of all four hydrolases were markedly elevated in two spontaneous adenomatous tumors found in the lungs of old mice. The data indicate that LAH play a significant role in lung growth and maturation, and in changes associated with

ISSN:0304-324X    

DOI:10.1159/000212154

出版商:S. Karger AG    

年代:1976

数据来源: Karger

摘要:

The conditions which must be satisfied by an index of biological age are discussed, and a high correlation with chronological age is shown to be neither a necessary nor a sufficient condition to be satisfied by any such index.

ISSN:0304-324X    

DOI:10.1159/000212155

出版商:S. Karger AG    

年代:1976

数据来源: Karger

摘要:

Enzyme activities and immunological reactivities of seven different enzymes have been assayed in the polymorphonuclear leukocytes from 10 newborns, 10 aged (over 80 years old) and 10 young adults (20–30 years old). Polymorphonu-clears have been chosen because both in the newborns, and in the aged people, they are young cells whose life span is a few hours only. Five cytoplasmic enzymes have been immunologically studied by means of mono-specific antienzyme sera: leukocyte pyruvate kinase by immunoinactivation, glu-cose-6-phosphate dehydrogenase and glucose phosphate-isomerase by electroimmu-nodiffusion, lactic dehydrogenase (muscle-type) by radial immunodiffusion. Two ly-sosomal enzymes (α-mannosidase and β-glycuronidase) have been titrated immunologically with the same polyvalent antihuman leukocyte rabbit serum. Small but significant differences in activity were observed for several of the enzymes. By contrast, no significant difference was found, for any of the seven enzymes, as regards the ratio enzyme activity/immunological reactivity, between newborns, young adults and aged people. These results do not support the theory that a decreased accuracy of the protein synthesis machinery is responsible for aging and death. By contrast, the authors emphasize that the enzyme abnormalities reported by various authors in old animals or in old fibroblast cultures closely resemble those demonstrated to be ‘post-translational modifications’ in the case of human glucose-6-phosphate dehydr

ISSN:0304-324X    

DOI:10.1159/000212156

出版商:S. Karger AG    

年代:1976

数据来源: Karger

摘要:

When applying various concentrations of NaCLO4 (0.15–7 m) to tendon fibres from rat tails, we found denaturation beginning at 2 m, and with increasing concentration a linear increase of the maximal contraction tension and an exponential shortening of the contraction time down to a minimal value of 7.5 min. In a second group of experiments we investigated the weight changes of tendons of old (26–30 months) and young (8 months) rats treated with 5 m NaCLO4 and compared the weight curves and the tension curves. We found an increase in weight up to 900% as the tension decreased. This indicates a connection between the swelling and the relaxation of collagen fibres. Other solutions of neutral salts (5 m NaCLO3, NaCl; 15 m NaCLO4, NaCLO3, NaCl) tested on young and old tendons did not produce any tension nor other visible changes. The weight curves show an immediate increase up to about 200% which remains constant and which is low compaired with the effect of 5 M NaCLO4. The reason for the contraction of tendon fibres seems to be the denaturation caused by the increased lipophilia of the aqueous salt solutions, while the relaxation is merely the result of the subsequent swelling of the collagen fi

ISSN:0304-324X    

DOI:10.1159/000212157

出版商:S. Karger AG    

年代:1976

数据来源: Karger

摘要:

The age dependence of the relative rate of biosynthesis of intercellular matrix macromolecules was studied in organ culture and cell culture obtained from aortas of newborn, young and adult rabbits. In organ culture there was a strong decrease with age of the rate of incorporation of [14C]-lysine and [3H]-glucosamine in all macromolecular fractions. Neosynthesis of elastin could be demonstrated by the isolation of labelled desmosine at all ages. In cell cultures derived from newborn and adult aortas, no decrease in total incorporation was noticed. The pattern of synthesis and secretion of glycosaminoglycans and glycoproteins did however change with age. These results suggest the existence of a matrix-dependent and of a matrix-independent regulation of the relative rate of synthesis of matrix macromolecules.

ISSN:0304-324X    

DOI:10.1159/000212158

出版商:S. Karger AG    

年代:1976

数据来源: Karger

ISSN:0304-324X    

DOI:10.1159/000212159

出版商:S. Karger AG    

年代:1976

数据来源: Karger

ISSN:0304-324X    

DOI:10.1159/000212160

出版商:S. Karger AG    

年代:1976

数据来源: Karger

ISSN:0304-324X    

DOI:10.1159/000212153

出版商:S. Karger AG    

年代:1976

数据来源: Karger