摘要:

The free radical theory of aging postulates that free radicals are the underlying cause of aging. One of the well-established age-associated disorders is the decrease in the insulin-stimulated glucose transport through the cell membrane which was reported to be a major mechanism underlying insulin resistance in old rats. The present study investigates the protective capacity of two known antioxidants, vitamin C and butylated hydroxytoluene (BHT), against age-associated free radical damage, which could be the reason behind the decreased insulin-stimulated glucose transport in old animals. Maximum insulin-stimulated glucose transport has been estimated in adipocytes isolated from adult 6-month-old Fischer rats and from senile 24-month-old control rats as well as from 24-month-old rats that were fed either vitamin C or BHT for 18 months. A significant increase in maximum insulin-stimulated glucose transport was observed in the BHT (p = 0.015) and the vitamin C groups (p = 0.039) compared with the control group of the same age. Significant stimulations with insulin over basal activities were also observed in the BHT group (p = 0.0001) as well as the vitamin C group (p = 0.009), while a nonsignificant stimulation (p = 0.097) was observed in the old control group. This study suggests a protective role that BHT (fat soluble) may have on the lipid moiety of the cell membrane and vitamin C (water soluble) on one or more of the intracellular cytoplasmic constituents concerned with glucose transport.

ISSN:0304-324X    

DOI:10.1159/000213699

出版商:S. Karger AG    

年代:1995

数据来源: Karger

摘要:

Age-related changes in plasma adrenocorticotropic hormone (ACTH), corticosterone, and aldosterone responses to exogenous corticotropin-releasing hormone (CRH) were studied concomitantly in both old and adult Long-Evans female rats. All animals were pretreated with dexamethasone and pento-barbital anesthetized. An acute intravenous injection of 1 μg rat CRH/100g body weight markedly increased the plasma concentrations of ACTH, corticosterone, and aldosterone – with similar temporal kinetics in the two groups of rats. However, the incremental CRH responses were significantly lower in old (approximately –70,–45–60, and –30–50%, respectively, for ACTH, corticosterone, and aldosterone) as compared with adult rats. Together with our recent findings, the present results suggest that the previously reported reduced secretion of corticosteroids in aged rats is due to both an impaired steroidogenetic capacity of adrenocortical cells to respond to ACTH and to a decreased ability of corticotropes to produce ACTH in response to CRH.

ISSN:0304-324X    

DOI:10.1159/000213700

出版商:S. Karger AG    

年代:1995

数据来源: Karger

摘要:

There are many problems in measuring ‘biological’ age rather than chronological age, not least the necessity of demonstrating that this measure has validity in terms of better predicting mortality or morbidity. This review considers nine problems in measuring biological age and attempts to provide a full or partial solution to these difficulties. The problems presented include the fact that different organs age at different rates; biological age depends on the parameters studied; ‘regression dilution bias’ may produce misleading results; the validity of the measurement has to be established; the age range for measures has to be agreed; persons affected by accident or disease may or may not be excluded; accidental deaths may have to be excluded from a study of validation; individuals age at different rates at different times, and the fact that longitudinal data are necessary. The solutions suggested include both the presentation of aging profiles including several systems and the provision of summary statistics; adjusting for ‘regression dilution bias’, and calculating rate of aging from longitudinal studies over different age ranges and in the two sexes separately. It is argued that in this field of research it is well worth confronting the difficulties and extending our body of knowledge by further care

ISSN:0304-324X    

DOI:10.1159/000213701

出版商:S. Karger AG    

年代:1995

数据来源: Karger

摘要:

This paper is a short critical essay about the value of ‘battery tests’ to predict the longevity of groups and individuals. It takes a standpoint that there is a long history behind efforts to define the concepts of ‘physiological age’, and ‘chronological age’, and their relationships with ‘lifespan’. The conclusion is that clinical measurements have little value in defining biological age and lifespan. These latter are the outcomes of uncorrected molecular errors which are far removed in time and place from their clini

ISSN:0304-324X    

DOI:10.1159/000213702

出版商:S. Karger AG    

年代:1995

数据来源: Karger

ISSN:0304-324X    

DOI:10.1159/000213703

出版商:S. Karger AG    

年代:1995

数据来源: Karger

摘要:

This study investigated, by questionnaire, the attitudes of geriatricians, speech therapists, dieticians, and nurses towards feeding by percutaneous endoscopic gastrostomy (PEG). The final response rate from a total of 199 questionnaires sent to this group was 75%. According to 95 (64%) of the respondents, the decision to use PEG feeding was reached by a multidisciplinary team approach and commonly involved carers as well as the patients. The quality of life was the single most important factor influencing this decision. PEG feeding was felt to be indicated in non-dysphagia-related malnutrition by 98 (66%) and in dementia with rejection of oral feeding by 69 (47%) of the respondents. It was felt by 39 (55%) of the nurses and by 32 (42%) of the other professionals that patients with dementia in long-term care who are established on nasogastric feeding should be converted to PEG feeding. This raises several ethical and resource issues.

ISSN:0304-324X    

DOI:10.1159/000213704

出版商:S. Karger AG    

年代:1995

数据来源: Karger

摘要:

To develop a new method for accurately predicting creatinine clearance (Ccr) in the debilitated elderly without urine collections, the total muscle volume of both thighs (MV thigh), as a new predictive parameter, was calculated using computed tomography in 68 debilitated patients aged 61–92 years. A regression line between 24-hour urinary creatinine excretion and MV thigh was divided by serum creatinine (Scr), and then the following formula was derived: Ccr(ml/min) = 9 × [MV thigh (cm3) –– 100]/[1,000 × Scr(mg&slash;dl)] Predicted Ccr by the new method more closely correlated with measured Ccr (r = 0.862) than did predicted Ccr by Cockcroft and Gault’s method (the C-G method) (r = 0.727). Statistical analysis of prediction error (= predicted Ccr-measured Ccr) suggested that the new method could provide more accurate and less biased estimations of Ccr than did the C-G method, even in patients with renal insufficiency. By using computed tomography, we have proposed a more accurate method for predicting Ccr of the debilitated elderly than the C-G method, although the new method has inherent disadvantages of radiation exposure and

ISSN:0304-324X    

DOI:10.1159/000213705

出版商:S. Karger AG    

年代:1995

数据来源: Karger

摘要:

Ninety-four institutionalized subjects (mean age 82.9 years; 13 men and 81 women) were assessed for serum dehydroepiandrosterone sulfate (DHEAS) levels. The mean value was 457 ng/ml (SD = 426) in this cross-sectional study. There was a significant decrease in DHEAS levels with age. There was no difference among demented patients with Alzheimer’s disease (n = 46), other dementia cases (n = 16), and other individuals (n = 32). The subjects treated for arterial hypertension had significantly lower DHEAS levels. No correlation was found between DHEAS and cortisol values. After age adjustment, no association was observed between DHEAS and chronic diseases, medications, several biochemical or hematological parameters, or 3-year mortalit

ISSN:0304-324X    

DOI:10.1159/000213706

出版商:S. Karger AG    

年代:1995

数据来源: Karger

ISSN:0304-324X    

DOI:10.1159/000213707

出版商:S. Karger AG    

年代:1995

数据来源: Karger

ISSN:0304-324X    

DOI:10.1159/000213708

出版商:S. Karger AG    

年代:1995

数据来源: Karger