摘要:

A characteristic feature of aging organisms is their loss in homeostatic functions, including the ability of protein synthesis and turnover. It has been proposed that in senescent Drosophila melanogaster the peptide synthesis elongation factor (EF) EF-1α may become limiting and be responsible for the age-related decline in protein synthesis. We have determined the expression levels of EF genes in Drosophila and have compared them with the expression of several other genes involved in the protein synthesis pathway. Steady-state levels of mRNAs for EF-1α F1 and F2, of mRNAs for four ribosomal proteins, of total poly A+ RNA, rRNA, and tRNA were measured. We show that most RNAs studied decrease immediately after eclosion. There is no evidence for EF-1α mRNA becoming limiting in old flies. Our data suggest that down-regulation of RNA polymerase I-, II-, and III-mediated transcription may contribute to an age-related decrease in protein synthesis or other homeostatic functio

ISSN:0304-324X    

DOI:10.1159/000213783

出版商:S. Karger AG    

年代:1996

数据来源: Karger

ISSN:0304-324X    

DOI:10.1159/000213784

出版商:S. Karger AG    

年代:1996

数据来源: Karger

摘要:

Transcription factor NFκB (nuclear factor κB) is induced in T lymphocytes from young individuals following activation with a variety of stimuli including anti-CD3, phorbol myristate acetate (PMA), and tumor necrosis factor-α (TNF-α). In contrast, activated T lymphocytes from older individuals show a significant reduction in the induction of NFκB in response to the same stimuli. The age-related decline in induction of NFκB could not be attributed to alteration in the composition of subunits, p50 and p65 were found to be the predominant subunits of induced NFκB in T cells from young as well as elderly donors. Furthermore, similar levels of NFκB were found in the cytosols of unactivated T cells from both young and elderly donors suggesting that precursor levels of NFκB remain unaltered during aging. These results suggest that an age-associated decline in the induction of NFκB in activated T cells from elderly individuals may be attributable to altered regulation of the inhibitor, IκB, and may play an important role in immune dysregulation accompan

ISSN:0304-324X    

DOI:10.1159/000213785

出版商:S. Karger AG    

年代:1996

数据来源: Karger

摘要:

The hypothesis of the coparticipation of ribosomal genes in controlling the differential expression of genes with age is analyzed in Down’s syndrome. The activity of ribosomal genes was tested cytogenetically by Ag-stained nucleolar organizer regions and by satellite association in lymphocytes from 40 patients with Down’s syndrome. Twenty patients were between 0 and 25 years old, and the others were between 29 and 48 years old. Our results showed a significant decrease with regard to total Ag staining and in relation to each chromosome pair in the older Down’s syndrome group as compared with the younger group. The total number of associated chromosomes and the number of associations of each chromosome pair were both significantly lower. The results show a decreased activity of ribosomal genes with age. This reduction may originate from changes in regulation and expression of these genes that might result in differing cell translation ab

ISSN:0304-324X    

DOI:10.1159/000213786

出版商:S. Karger AG    

年代:1996

数据来源: Karger

摘要:

Objectives of this study were to determine the prevalence of positive tuberculin reactivity and associated factors among elderly nursing home residents in a population with a relatively high tuberculosis notification rate, to estimate the prevalence of active tuberculosis, and to assess tuberculin reactivity as a screening tool. A stratified, disproportional, randomized cluster sample of residents was selected and the Mantoux test (using 0.1 ml of 5 tuberculin units of purified protein derivative of tuberculin) carried out. All subjects with a positive test had a chest X-ray followed by sputum smear and culture if the X-ray was abnormal. Sputum examination was also carried out in a random sample of controls, matched for age and gender, drawn from subjects with a negative Mantoux test. Information regarding medical history, tobacco smoking habits, symptoms related to tuberculosis, and communal eating habits were gathered. Also anthropometric data were collected. Sixteen nursing homes in the catchment area of a major district hospital in Hong Kong comprising 587 residents (136 men, 451 women, mean age 80 ± 8 years) participated in this study. The weighted prevalence of tuberculin reactivity was 43.8%. It was higher in men, among those who took their meals in a common area, in the younger age group, and in those with no previous history of hospitalization. No association was found between prevalence and duration of residence, smoking, skinfold thickness, past medical history, or any relevant symptoms. Following radiological and sputum examination, the estimated prevalence of active tuberculosis ranged from 1.2 to 2.6%. The sensitivity of the tuberculin test was 86, the specificity 30%. The prevalence of active tuberculosis in nursing homes in Hong Kong is high, but it is unclear whether cross-infection or poor health of the residents is the major contributing factor. Tuberculin skin testing does not appear to be a useful screening method in this population

ISSN:0304-324X    

DOI:10.1159/000213787

出版商:S. Karger AG    

年代:1996

数据来源: Karger

摘要:

Sleep symptoms, cognitive, psychic, and physical health variables were assessed in a sample of 449 community-dwelling elders aged 75 and over. The subjects were in a good cognitive and functional condition. Three night sleep symptoms were evaluated: difficulty falling asleep, waking up frequently in the night, and early morning awakenings. For each symptom, respondents were asked to estimate the frequency of the symptom during the past month on a five-point scale. White-collar workers reported the best, and blue-collar workers the poorest quality of sleep: the difference in the difficulty of falling asleep between the two groups was 0.86, of waking up frequently in the night 0.93, of early morning awakenings 1.01 (corresponding to 3 days/month, 5 days/month, and 3.5 days/month, respectively), and of total sleep symptoms 2.81. These unadjusted differences were reduced, respectively, to 0.57, 0.42, 0.54, and 1.53 after adjustment for other factors. Of these, only waking up frequently in the night was not statistically significant. These data show more frequent sleep symptoms in socially disadvantaged occupational groups, suggesting that social factors can significantly affect the quality of sleep in the elderly.

ISSN:0304-324X    

DOI:10.1159/000213788

出版商:S. Karger AG    

年代:1996

数据来源: Karger

摘要:

Synaptic junctional areas are not immutable structures, on the contrary, they are remodelled throughout the individual’s life-span as a consequence of environmental stimulations. This adaptive capacity of the synapses is discussed from a morphological standpoint with reference to aging. In old subjects, the number of contacts and the total surface area of synaptic appositions per unit volume of tissue decrease significantly, while the average synaptic size increases at a different extent according to the CNS area taken into account. This increase in synaptic average area is due to a higher percent of a subpopulation of enlarged contacts supposed to represent either the degenerating junctional zones or a compensatory phenomenon counteracting the synaptic reduction in number. Recent studies on perforated synapses support that the enlarged junctions are possible intermediates in synaptic physiological restructuring, thus the higher percentage of this type of contacts in the old CNS may witness unaccomplished synaptic turnover cycles. Taking into account the high metabolic rate of nerve cells, an age-related impairment in energy provision at synaptic terminal regions may constitute an early and subtle alteration affecting synaptic dynamic morphology in agin

ISSN:0304-324X    

DOI:10.1159/000213789

出版商:S. Karger AG    

年代:1996

数据来源: Karger

ISSN:0304-324X    

DOI:10.1159/000213790

出版商:S. Karger AG    

年代:1996

数据来源: Karger