摘要:

We have shown that ultrastructural changes accompany ageing in the human fetal lung fibroblast strain MRC-5. In order to further characterise these changes a method has been devised to prepare subcellular fractions from MRC-5 fibroblasts using a discontinuous gradient of metrizamide preceded by a low-speed centrifugation. An investigation was carried out to compare subcellular fractions prepared from early-passage and senescent cells. Proteolytic activity associated with lysosomes and soluble proteolytic activity were found to be increased in senescent cells.

ISSN:0304-324X    

DOI:10.1159/000212358

出版商:S. Karger AG    

年代:1979

数据来源: Karger

摘要:

When given orally to young and old rats, pregnenolone-16α-carbonitrile, spironolactone, or phenobarbital, known microsomal enzyme inducers, caused an increase in smooth endoplasmic reticulum. Dexamethasone, while a potent microsomal enzyme inducer, did not cause smooth endoplasmic reticulum increase. In both untreated and treated old rats, there was dilatation and vesiculation of rough endoplasmic reticulum with occasional granular material present in vesicles. Cytoplasmic lipid droplets of various sizes were frequent. Some mitochondria exhibited polymorphism and a variation in matrical density. Lysosomes and autophagic vacuoles as well as lipid droplets of various sizes were frequent in all groups. These results show that microsomal enzyme inducers influence the subcellular structure of hepatocytes in old rats

ISSN:0304-324X    

DOI:10.1159/000212359

出版商:S. Karger AG    

年代:1979

数据来源: Karger

摘要:

The proportion of ribosomes active in protein synthesis and the content of polyribosomal poly(A)-containing RNA are unchanged when adult and senescent rat livers are compared. Therefore, the decreased protein synthesizing activity of senescent liver microsomes observed previously is not due to a deficiency in total mRNA content.

ISSN:0304-324X    

DOI:10.1159/000212360

出版商:S. Karger AG    

年代:1979

数据来源: Karger

摘要:

Young adult (6–12 weeks old) and aged (20–24 months old) NMRI mice were infected with various intracellular parasites. The following results were obtained: (1) After a sublethal infection with Listeria monocytogenes, aged mice were found to show a resistance similar to that of young adults. A challenge infection with this pathogen was followed by specific immunity of long duration in both age-groups. (2) On the other hand, young animals were significantly more resistant to Salmonellatyphimurium than aged mice. It was concluded that this was due to the LD50 which was 14 times greater for 2-month-old than for 20-month-old mice. Furthermore, during 7 weeks after infection there were more S. typhimurium in the spleens of senescent mice than in those of young adult controls. (3) Aged mice showed highly increased susceptibility to the weakly virulent DX strain of Toxoplasma gondii. Almost all aged animals died whereas the control mice survived. When death of the aged mice was prevented by treatment with sulfadiazine after infection with the DX strain, the aged mice were found to be as well protected against subsequent infection with the strongly virulent BK strain as the young adult mice. These results suggest that the susceptibility of the aged animal to infectious agents may considerably vary from one pathogen to anot

ISSN:0304-324X    

DOI:10.1159/000212361

出版商:S. Karger AG    

年代:1979

数据来源: Karger

摘要:

44 people were recorded by a telemetric system during 8 h of daily occupational activity. 24 were factory personnel (12: mean age 37 years, and 12: mean age 53 years) and 20 were university researchers (10: mean age 39 years, and 10: mean age 53 years). Recordings were made concerning EEG, EOG, EMG, and EKG. At 35 years no differences were observed. At 50 years the organization of wakefulness was different for the two occupational activity groups. Although stable for the factory personnel, it was less in the afternoon for the university group. The activity of the moment seemed to play a prominent role in the modulation of wakefulness.

ISSN:0304-324X    

DOI:10.1159/000212362

出版商:S. Karger AG    

年代:1979

数据来源: Karger

摘要:

The feasibility and value of conducting health screening programmes for elderly people using self-administered postal questionnaires is discussed in relation to the outcome of a community study of mobility problems in the elderly. It is argued that this procedure minimizes the work and expense involved in organising and carrying out such programmes.

ISSN:0304-324X    

DOI:10.1159/000212363

出版商:S. Karger AG    

年代:1979

数据来源: Karger

摘要:

The vitamin D status of residents of an old people’s home and long-stay patients was assessed by means of plasma 25-hydroxycholecalciferol (25-OHD) estimations. The residents of the old people’s home had a higher mean plasma 25-OHD concentration than long-stay patients. Both groups had diets with vitamin D intakes of less than 2.5 μg (100 IU) per day and the conclusion is that solar exposure is the major determinant of the concentration of circulating 25

ISSN:0304-324X    

DOI:10.1159/000212364

出版商:S. Karger AG    

年代:1979

数据来源: Karger

ISSN:0304-324X    

DOI:10.1159/000212365

出版商:S. Karger AG    

年代:1979

数据来源: Karger

ISSN:0304-324X    

DOI:10.1159/000212366

出版商:S. Karger AG    

年代:1979

数据来源: Karger

ISSN:0304-324X    

DOI:10.1159/000212367

出版商:S. Karger AG    

年代:1979

数据来源: Karger