RESUMO
The ribosomal RNA (rRNA) genes are located in nucleolus during active transcription and are transcribed by RNA polymerase I. This group of genes is involved in transcription and translation processes which can modulate gene expression. The association between rRNA levels and aging has been reported. In the present study, we investigated the ratio of mature rRNA 28S and 18S in peripheral blood of 15 Alzheimer's disease (AD) patients, 15 elderly healthy controls and 15 healthy young controls. Our results showed a statistically significant decrease of the mature rRNA 28S/18S ratio in AD patients when compared with the elderly and young control groups. Thus we can suggest that there is a possible change in the transcriptional or maturation process or a preferential degradation of the 28S subunit in AD.
Assuntos
Doença de Alzheimer/genética , RNA Ribossômico 18S/análise , RNA Ribossômico 18S/genética , RNA Ribossômico 28S/análise , RNA Ribossômico 28S/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , Envelhecimento/genética , Estudos de Casos e Controles , Regulação da Expressão Gênica , Humanos , Pessoa de Meia-IdadeRESUMO
Fragile sites have been interesting for mapping chromosomal regions involved in disease and ageing. The chromosomal fragile site expression from 38 Down's syndrome (DS) individuals aged 0-48 years was investigated in blood peripheral lymphocytes. Fragile sites were statistically characterized as the minimum expected number of lesions per band based on a Poisson distribution. The results showed that the fragile site 2q11 was associated with the DS condition and fragile sites 5q31, 6p21 and 9q12 with ageing in DS subjects. Fragility in 6p21 has also been associated with Alzheimer's disease patients.
Assuntos
Envelhecimento/genética , Fragilidade Cromossômica , Cromossomos Humanos Par 2 , Cromossomos Humanos Par 5 , Cromossomos Humanos Par 6 , Cromossomos Humanos Par 9 , Síndrome de Down/genética , Adolescente , Adulto , Pré-Escolar , Sítios Frágeis do Cromossomo , Humanos , Lactente , Pessoa de Meia-IdadeRESUMO
Age-related increases in the frequencies of cells with chromosome 21 loss and of polyploid cells were documented in short-term peripheral blood lymphocyte cultures from 54 patients with Down's syndrome (DS), ages 0 to 48 years. The polyploid data, together with previous work from this laboratory with non-DS subjects, suggest that this may be a useful indicator of aging in lymphocytes.
Assuntos
Envelhecimento/genética , Cromossomos Humanos Par 21 , Síndrome de Down/genética , Mosaicismo , Poliploidia , Adolescente , Adulto , Criança , Pré-Escolar , Feminino , Humanos , Lactente , Masculino , Pessoa de Meia-IdadeRESUMO
A relationship between telomere shortening and ageing has been established. A series of young and elderly healthy donors. Alzheimer disease patients, young and old Down's syndrome individuals were cytogenetically analyzed. No preferential damage in distal bands was seen in age-related chromosome instability.
Assuntos
Envelhecimento/genética , Doença de Alzheimer/genética , Aberrações Cromossômicas/genética , Síndrome de Down/genética , Telômero/ultraestrutura , Estudos de Casos e Controles , Transtornos Cromossômicos , HumanosRESUMO
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 ability.
