ISSN:1363-1950    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

The prevalence of malnutrition, which is relatively low in free-living elderly persons (5-10%), is considerably higher (30-60%) in hospitalized or institutionalized elderly persons. As a result, nutritional assessment should be part of routine clinical practice in elderly patients who are frail, sick or hospitalized. A comprehensive screening tool for assessment of nutritional status is needed that is clinically relevant and cost-effective to perform. A number of simple and rapid tests for detecting or diagnosing malnutrition in the elderly have recently been developed. If malnutrition is suggested by such screening tests, then they should be supplemented by conventional nutritional assessment before treatment is planned.

ISSN:1363-1950    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

Over the lifespan there is a decline in food intake. This has been termed the physiological anorexia of aging. It has many causes, including alterations in the gastrointestinal satiating system, the effect of elevated leptin levels, especially in men, and a variety of changes in central nervous system neurotransmitters. Beyond the age of 70 years body mass declines. This includes both loss of adipose tissue and muscle mass. The loss of muscle mass in older individuals is termed sarcopenia. There is increasing evidence that this is caused, in men, partly by the decline in testosterone. Illness results in an increase of cytokines that produce both anorexia and cause protein wasting. Many of the causes of cachexia in older individuals are treatable. Depression is the most common cause of weight loss in older individuals. Dieting in older individuals is associated with a loss of skeletal tissue as well as fat mass. This can place older individuals at risk of becoming the ‘fat frail’

ISSN:1363-1950    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

Calcium and vitamin D deficiency increase age-related bone loss by causing secondary hyperparathyroidism. Reduced endogenous vitamin D synthesis exacerbates the problem of dietary deficiency and involves elderly people living in their own homes, who are just as much at risk as those living in institutionalized care. The effects of secondary hyperparathyroidism may be offset by hypercalcaemia of the increased bone turnover of immobility, which has a direct adverse effect on the skeleton causing osteoporosis. Active vitamin D analogues are effective in suppressing secondary hyperparathyroidism caused by vitamin D deficiency. However, simple deficiency is optimally treated with parent vitamin D, which has a greater safety margin than active vitamin D therapy (1,25 dihydroxyvitamin D), which requires close monitoring in the elderly.

ISSN:1363-1950    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

Under-nutrition is common in elderly patients, especially for those in hospital. Hospital stay is often associated with further weight loss. Many authors have considered nutritional supplementation. A recent meta-analysis of the trials of nutritional supplementation in all age groups and pathologies found benefits from supplementation but suggested that further work was required. This review considers the work done since the meta-analysis until the end of 1999 and in particular considers the benefits evident to elderly patients using oral supplements.

ISSN:1363-1950    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

Older people with dementia are often prescribed numerous medications. Use of herbal therapies in addition to these conventional drug therapies may lead to interactions that result in an adverse drug event. We have conducted a systematic review to identify all studies that examined interactions between herbal and conventional drug therapies (i.e. prescription or over-the-counter). Using a MEDLINE search of English-language studies published between 1980 and 2000, we limited our search to those herbal therapies most likely to be used for the treatment of dementia (memory loss and decreased concentration) and related symptoms. We identified 28 articles that describe interactions between these herbal (i.e. St. John's wort, ginkgo biloba, kava, valerian, and ginseng) and conventional drug therapies. Of these articles, 11 examined St. John's wort, four examined ginkgo biloba, five examined kava, one examined valerian, and seven examined ginseng. We identified a series of potential interactions between herbal and conventional drug therapy that place older people at risk for an adverse drug event. Health care professionals need to be aware of these potential interactions.

ISSN:1363-1950    

出版商:OVID    

年代:2001

数据来源: OVID

ISSN:1363-1950    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

Historically, amino acids have been viewed as precursors for protein synthesis as well as metabolic substrates. Recently, a new role for amino acids as regulators of mRNA translation has been identified. In this role, they modulate the phosphorylation state of proteins that represent important control points in translation initiation, including the translational repressor 4E-BP1 and the ribosomal protein S6 kinase S6K1. When administered orally to fasted rats the branched-chain amino acids are particularly effective in stimulating translation initiation. Of the branched-chain amino acids, leucine is most potent. Interestingly, leucine administration stimulates global rates of protein synthesis in skeletal muscle but not in liver. However, in liver, branched-chain amino acids enhance the translation of a particular set of mRNAs typified by those encoding the ribosomal proteins and translation elongation factors, suggesting that branched-chain amino acids upregulate the capacity of the tissue to synthesize protein.

ISSN:1363-1950    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

The mechanisms of proteolysis remain to be fully defined. This review focuses on recent advances in our understanding of the ubiquitin-proteasome-dependent pathway, which is involved in the control of many major biological functions. The ubiquitinylation/deubiquitinylation system is a complex machinery responsible for the specific tagging and proof-reading of substrates degraded by the 26S proteasome, as well as having other functions. The formation of a polyubiquitin degradation signal is required for proteasome-dependent proteolysis. Several families of enzymes, which may comprise hundreds of members to achieve high selectivity, control this process. The substrates tagged by ubiquitin are then recognized by the 26S proteasome and degraded into peptides. In addition, the 26S proteasome also recognizes and degrades some non-ubiquitinylated proteins. In fact, there are multiple ubiquitin- or proteasome-dependent pathways. These systems presumably degrade specific classes of substrates and single proteins by alternative mechanisms and could be interconnected. They may also interfere or cooperate with other proteolytic pathways.

ISSN:1363-1950    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

The most common methods for measuring the incorporation of tracer amino acids into tissue protein are the constant tracer infusion and the flooding dose. The flooding dose is an attractive method for measuring tissue protein synthesis because of its convenience and precision. A primary assumption of the method, that the free amino acid precursor pools are equilibrated with the true precursor pool, aminoacyl-transfer RNA, has recently been validated. When short labelling periods are involved, the large dose of amino acid does not appear to alter protein synthesis. The constant tracer infusion is a satisfactory method from a theoretical point of view, but its use requires the measurement of the protein synthetic precursor pool. The best estimate of the aminoacyl-tRNA precursor pool for the constant infusion method appears to be the acid-soluble tissue pool in muscle and VLDL apolipoprotein B-100 in the liver. The experimental approach chosen for measuring tissue protein synthesis should be dictated by the question being addressed.

ISSN:1363-1950    

出版商:OVID    

年代:2001

数据来源: OVID