ISSN:0304-324X    

DOI:10.1159/000212673

出版商:S. Karger AG    

年代:1984

数据来源: Karger

摘要:

Human skeletal muscle has been studied in vivo by 31P nuclear magnetic resonance. Young adult subjects were compared with healthy elderly subjects aged 70–80 years. Intracellular pH and concentrations of adenosine triphosphate (ATP), phosphocreatine and inorganic phosphate were measured. At rest, no differences were found between the two age groups. Aerobic dynamic exercise resulted in a similar reduction of phosphocreatine in both groups while the ATP concentration did not change. The pH fall in exercise was not significantly different in the elderly and younger subjects. The time to resynthesize ATP in the recovery period as measured by the time to replete phosphocreatine was also not different in the two groups. The results suggest that the aging process does not affect the metabolic ability of human skeletal muscle to respond to exercise and that changes found in muscle of the elderly are not due to alterations in energy productio

ISSN:0304-324X    

DOI:10.1159/000212599

出版商:S. Karger AG    

年代:1984

数据来源: Karger

ISSN:0304-324X    

DOI:10.1159/000212674

出版商:S. Karger AG    

年代:1984

数据来源: Karger

摘要:

The adequacy of the Gompertz-Makeham law (Rt = Beαt + A) for a description of human mortality was tested. The analysis was based on statistical data of current mortality rates in men and women of 35 countries for 5 calender years. The study tested the justification of the part of the Gompertz-Makeham law postulating that age-associated mortality (i.e. Beαt) increases exponentially. It was found that the α parameter of the age component of the Gompertz-Makeham law was not a constant value within the age range 35–75 years, but had rather an age-associated shift which was qualitatively different in men and women. The conclusion was made that the Gompertz-Makeham law did not adequately describe the mortality pattern of a modern human population. This should be borne in mind when use is made of mortality indices for the analysis of the human aging pro

ISSN:0304-324X    

DOI:10.1159/000212600

出版商:S. Karger AG    

年代:1984

数据来源: Karger

摘要:

To clarify the intrinsic process of aging in aorta, the lipid metabolism was investigated in serum, aorta, and liver of 24-month-old rats in comparison to 10-month-old animals. Serum total cholesterol and the lipid content of low-density lipoprotein slightly increased in aged animals. Enzyme activities which hydrolyze or synthesize cholesterol ester or triglyceride in aorta were enhanced in aged animals. The increase in hydrolysis overcame that in synthesis, suggesting that enzyme activities were not changed in order to accumulate cholesterol ester and triglyceride in the aorta with aging. Phospholipid content and choline phosphotransferase activity were low both in the aorta and liver of aged animals. Moreover the phospholipid to free cholesterol ratio was decreased in aged animals, suggesting a change of membrane property with aging.

ISSN:0304-324X    

DOI:10.1159/000212601

出版商:S. Karger AG    

年代:1984

数据来源: Karger

摘要:

In the erythrocytes of individuals below 30 and above 60 years of age, the activities of several ATPases, the contents of ATP, ADP and AMP as well as the concentration of sialic acid on the erythrocyte membrane were measured. All parameters decreased with the sole exception of AMP which increased with age.

ISSN:0304-324X    

DOI:10.1159/000212602

出版商:S. Karger AG    

年代:1984

数据来源: Karger

摘要:

The mean life span of Callosobruchus maculatus male is 7 days and female is 5 days at 30 ± 1°C. Age-related study on C maculatus shows that RNA and protein contents gradually decline with age in male bruchids, whereas in females initially these increase up to the second day of post-emergent life and subsequently decrease. DNA increases up to the third day in males and the fourth day in females representing post-emergent growth, and then declines sharply on the sixth day. The RNA and protein contents per unit DNA decrease steadily in males; however, in females both are highest during the first 2 days, which synchronizes the egg-laying peak. These observations have been found to be statistically significant (p < 0.01) and suggest that aging is accompanied by a decrease in both RNA and protein synthesis potentia

ISSN:0304-324X    

DOI:10.1159/000212603

出版商:S. Karger AG    

年代:1984

数据来源: Karger

摘要:

Autoregulation of cerebral blood flow (CBF) to the controlled hemorrhagic hypotension was studied in young adult spontaneously hypertensive rats (SHR, 3.4 months of age) and aged SHR (20.3 months). There were no differences in average values for mean arterial pressure and baseline CBF between two groups of rats. During hypotension, however, CBF was more reduced in aged SHR than in young SHR, indicating that the lower limit of cerebral autoregulation is shifted to a higher level in aged SHR. Such upward shift of the autoregulation is likely due to a long-lasting hypertension which may lead to the diminished vasodilatory response of the brain to hypotension.

ISSN:0304-324X    

DOI:10.1159/000212604

出版商:S. Karger AG    

年代:1984

数据来源: Karger

摘要:

Cyclic AMP-dependent and -independent protein kinase have been isolated from livers of rats at 3, 9, 18 and 30 months of age. A preliminary characterization reported here reveals that in addition to a decrease in their activities due to ageing and a likely shift to cyclic AMP-independent casein kinase activity at 30 months of age, the enzymes show modest changes in some of their kinetic properties. In the case of cyclic AMP-dependent enzymes, decreases in Vmax for ATP and Km for cyclic AMP as well as histones were observed. On the contrary, casein kinases displayed increases in Km values for casein, GTP and ATP. Molecular weights of 143,000 daltons for casein kinases from 3-, 9- and 18-month-old rats and 211,000 daltons for that from 30-month-old rats were obtained. Slight differences were also noticed in the inhibitor sensitivity (NaF and 2,3-diphosphoglyceric acid) of casein kinases isolated from rats of different ages.

ISSN:0304-324X    

DOI:10.1159/000212605

出版商:S. Karger AG    

年代:1984

数据来源: Karger

摘要:

The effect of ageing on voluntary and electrically evoked muscle force was investigated. A group of 70-year-old men and a control group of young men took part in the study. The muscles studied were the elbow flexor group and the triceps surae group of the leg. With ageing both muscle groups showed a reduction in maximum voluntary force and in the force of electrically evoked tetani. The reduction was greatest in the leg muscles. The time to peak of the twitch was prolonged with age in the leg muscles. The findings are discussed in relation to the changes in fibre type known to occur in elderly muscle.

ISSN:0304-324X    

DOI:10.1159/000212606

出版商:S. Karger AG    

年代:1984

数据来源: Karger