摘要:

The replicative ability of variously ‘aged’ cell cultures, their insulin binding and biological responsiveness under control and glucocorticoid (i.e. hydrocortisone) amplified conditions have been studied in human fibroblast cultures. Insulin stimulation of DNA synthesis in early and late passage cultures and in cultures from young and old donors showed no age-related difference in insulin responsiveness. Hydrocortisone amplification of insulin-stimulated DNA synthesis in early and late passage cells expressed no age-related differences. Hydrocortisone affected basal DNA synthesis in cultures from in vivo young and old donors differently. Additionally, hydrocortisone amplified insulin-stimulated DNA synthesis in young donor cell cultures was observed to be higher than in old donor cell cultures. Specific 125I-insulin binding was increased by hydrocortisone in both early and late passage cultures and in cultures from young and old donors but no age-related differences in 125I-insulin binding were observed in the presence or absence of hydrocortisone. The data suggest that an age-related loss of an insulin postreceptor interaction during hydrocortisone amplification of insulin-stimulated DNA synthesis is being expressed in the cultures from old don

ISSN:0304-324X    

DOI:10.1159/000212683

出版商:S. Karger AG    

年代:1985

数据来源: Karger

摘要:

The lipolytic response of isolated adipocytes from 1 ½-, 6-, 24- and 32-month-old rats to various doses of epinephrine was studied. Both the basal and the maximal stimulated glycerol release were largest in the mature rats (6 months old) which had the largest adipocytes. Expressing glycerol release per unit cell surface area (which was drastically reduced with age) eliminated the difference between mature and senescent rats both in absence of epinephrine and at high doses of the hormone. However, at low epinephrine doses the adipocytes of the very young and the very old rats showed an enhanced response per unit surface area. A simple pharmacodynamic analysis based on the occupancy theory of drug-receptor interaction suggests that the sensitivity of rat adipocyte receptors is increased during senescence; this increase may be related to the decreased surface of old adipocytes. On the other hand, the decreased maximal lipolytic response during senescence may be due in part to a reduced number of receptors and to a reduced sensitivity of the cellular enzymatic system underlying lipolysis

ISSN:0304-324X    

DOI:10.1159/000212684

出版商:S. Karger AG    

年代:1985

数据来源: Karger

摘要:

The experiments on adult (4–6 months) and old (28–30 months) rats revealed changes that develop in old age in various links of the regulatory system of aldosterone secretion: the hypothalamic-hypophyseal control of mineralocorticoid secretion decreased, and the sensitivity of the glomerular zone to ACTH, vasopressin, and K+, as well as that of the myocardium, skeletal muscle and kidney to aldosterone increased. Changes in tissue sensitivity to aldosterone may be due to the increased affinity of mineralocorticoid receptors to aldosterone in old

ISSN:0304-324X    

DOI:10.1159/000212685

出版商:S. Karger AG    

年代:1985

数据来源: Karger

摘要:

Glutamine synthetase (GS) activity was measured in whole brain, different brain areas, liver and heart of 23- to 26-month-old rats, and then compared to matched animals of 3 months. A significant increase of GS activity was found in whole brain (25%) of old rats, as well as in all brain areas studied, but particularly in midbrain (36%), hypothalamus (32%), brainstem (32%), striatum (27%) and cerebellum (22%). A significant decrease of GS activity (21%) was found in liver and no significant difference in heart of old rats when compared to matched animals of 3 months. The present results suggest that an increase of GS activity in brain of old rats may be an adaptive phenomenon, and the regulatory mechanisms for GS with increasing age are different, depending on the tissues.

ISSN:0304-324X    

DOI:10.1159/000212686

出版商:S. Karger AG    

年代:1985

数据来源: Karger

摘要:

In 8 young and 8 elderly subjects mean values of plasma beta-endorphin were nearly equal under basal conditions. In all subjects the cold pressor test provoked a marked increase of beta-endorphin, which was more evident in young subjects. Mean values of the areas of endorphin modifications were the same in both young and elderly subjects. These results may suggest that after a short-term stimulus, such as the cold pressor test, no marked differences in pituitary secretion between young and elderly subjects may be evidenced.

ISSN:0304-324X    

DOI:10.1159/000212687

出版商:S. Karger AG    

年代:1985

数据来源: Karger

摘要:

That the steep increase of mean life expectancy in the developed countries during the first decades of this century has now come to a halt is neither news nor reason for panic. Mean life span cannot exceed the apparent biological limit for the human species, a maximum life span LSmax of 100–110 years, that has remained unchanged across time, races and civilizations; it will moreover remain about 20% less than LSmax even if major diseases were to be eliminated due to the inherent individual differences – only a few individuals are endowed with a genetic-physiologic profile that allows them to reach LSmax. Some concepts on the relation of rates of aging and dying and the mechanism of mortality are here pertinent and are amplified. Finally, though the author has extensively criticized the general applicability of the Gompertz ‘law of mortality’, he has some reservations concerning the recently expressed view that the course of the rate of increase of force of mortality with age may be different in men and women, chiefly slowing down versus continuously increasing; this conclusion may well be an artifact of the a

ISSN:0304-324X    

DOI:10.1159/000212688

出版商:S. Karger AG    

年代:1985

数据来源: Karger

摘要:

A cross-sectional survey of bowel habit has been carried out on 201 elderly patients living at home. Although symptoms of constipation were common, reported bowel frequency was similar to younger people. Constipation was most clearly associated with poor mobility and depression. Digital rectal examination was generally unreliable as an indicator of constipation. Using the abdominal radiograph as the final arbiter, true constipation was present in less than half of those complaining of constipation.

ISSN:0304-324X    

DOI:10.1159/000212689

出版商:S. Karger AG    

年代:1985

数据来源: Karger

摘要:

A chronobiological study was carried out in 10 elderly male subjects (78–83 years) to evaluate the 24-hour thyroid-stimulating hormone (TSH) secretory pattern. 10 young adult males (26–35 years) made up the control group. Hourly blood samples were drawn from each subject for a 24-hour period. TSH levels in elderly subjects showed blunted circadian fluctuations compared to those seen in young adult subjects. Mean 24-hour TSH values in elderly (3.1 ± 0.3 μU/ml) and young adult subjects (3.5 ± 0.1 μU/ml) did not differ statistically, but nighttime TSH values observed in elderly subjects (3.2 ± 0.3 μU/ml) were lower (p < 0.05) than those recorded in young adults (4.1 ±

ISSN:0304-324X    

DOI:10.1159/000212690

出版商:S. Karger AG    

年代:1985

数据来源: Karger

ISSN:0304-324X    

DOI:10.1159/000212691

出版商:S. Karger AG    

年代:1985

数据来源: Karger

ISSN:0304-324X    

DOI:10.1159/000212692

出版商:S. Karger AG    

年代:1985

数据来源: Karger