ISSN:1363-1950    

出版商:OVID    

年代:2004

数据来源: OVID

摘要:

Purpose of reviewTo investigate emerging data on the relationship between obesity, increased morbidity and mortality, and decreased function in the elderly. To examine what is known about the effectiveness of interventions, and how treatment might be improved.Recent findingsObesity is a common problem in the elderly, although its prevalence decreases in extreme old age. Decreased physical activity and decreased energy expenditure with ageing predispose to fat accumulation and fat redistribution. Reduction in muscle mass (sarcopenic obesity) is an important determinant of physical function and metabolic rate. Chronic inflammation and endocrine changes contribute to the changes in metabolism and body composition that accompany ageing, and are potential therapeutic targets. Body weight and body mass index are imperfect indicators of risk from obesity. The focus of treatment should be on reduction of intra-abdominal fat and preservation of muscle mass and strength. A number of recent studies have confirmed the effectiveness of exercise interventions in the elderly. Progressive resistance training, rather than endurance exercise, may be more effective in many cases. Reduced function and decreased quality of life accompany development of the complications of obesity such as diabetes and vascular disorders. There is considerable scope to impede the development of these complications in the elderly with lifestyle interventions.SummarySarcopenic obesity, with accumulation of intra-abdominal fat, is a major determinant of health status in the elderly. As in the younger population, prevention and treatment programmes have the potential to decrease the impact of diabetes, vascular disease, and other complications of obesity.

ISSN:1363-1950    

出版商:OVID    

年代:2004

数据来源: OVID

摘要:

Purpose of reviewThis review will focus chiefly on recently published studies utilizing air-displacement plethysmography (i.e. BOD POD) in geriatric populations. This innovative technology has been available commercially since 1995. As the test procedure is relatively easy to perform and quick, it may provide an improvement in body composition testing, especially in older individuals with poor ambulation and health.Recent findingsThis review will explain in a concise and detailed manner the underlying principles of air-displacement plethysmography specifically related to the BOD POD. Second, it will review the studies using this new technology in comparison with more commonly used techniques (hydrostatic weighing, dual energy X-ray absorptiometry, deuterium oxide, multi-compartmental models) for body composition analysis in geriatric populations. Third, it will provide a direction for future studies.SummaryA review of the current body of literature in which air-displacement plethysmography was used is beginning to emerge with a clear picture. Although this technique is still new, it appears that air-displacement plethysmography is a valid and reliable alternative to more traditional body composition techniques, as indicated by small mean differences between techniques. This has special implications in a geriatric population because traditional techniques are difficult to perform in individuals with joint pain, ambulation issues, and overall poor health.

ISSN:1363-1950    

出版商:OVID    

年代:2004

数据来源: OVID

摘要:

Purpose of reviewThere is currently intense interest in understanding why certain elderly individuals become frail and disabled with age whereas others do not. Is frailty the result of an acceleration of normal aging processes or is it the result of chronic medical conditions that are superimposed on the conventional mechanisms of aging? The clinical problem of falls has long been recognized as a threat to some elderly individuals, but too often is not considered worthy of objective study. The factors underlying falls are now being investigated as part of the increasing attention being paid to the evolution of frailty in the elderly.Recent findingsFrailty in the elderly has been given many names, but increasing efforts are now being made to define frailty in a standardized way that would allow more objective study. The frail elderly patient usually shows loss of both neurological and muscle function. Falls in the elderly are an example in which deterioration may be present in both functions. Methods are being developed to separate the loss of muscle capacity from the associated loss of central and peripheral neurological function involved in gait and balance.SummaryThe definition of frailty has been centered around the onset of accelerated weight loss with an associated decrease of mass and strength of skeletal muscle. New studies are discussed that extend this definition. Methods for a more detailed analysis of the physiological and metabolic deficits leading to falls in the elderly may provide a better understanding of frailty in general.

ISSN:1363-1950    

出版商:OVID    

年代:2004

数据来源: OVID

摘要:

Purpose of the reviewAdverse drug interactions may be the fourth leading cause of death in hospitalized patients. In children and older adults undetected food-drug interactions may lead to serious morbidity and mortality and be misdiagnosed as chronic disease progression. Recent recognition of the effects of certain foods on many drugs metabolized by CYP450 families or drugs susceptible to chelation and adsorption have increased awareness for prevention of food-drug interactions.Recent findingsPolypharmacy, self-medications with non-prescription drugs including herbal remedies, dietary/nutritional supplements, fortified foods, and polymorphism in drug metabolism increase the need to consider food-drug interactions. Improved food processing and analysis have led to overall decreased risk in monoamine oxidase inhibitor regimens with counseling. Drugs may create submarginal nutrient deficiencies with serious consequences, such as diuretics contributing to thiamin deficiency and further cardiac failure. Foods may contain compounds that lead to therapeutic failure, such as calcium-fortified foods producing therapeutic failure and promoting resistance in antibiotic therapy. Poor nutritional status can lead to poor health outcomes.SummaryPrevention of adverse events from food-herb-drug interactions requires clinical monitoring in high-risk regimens and populations. Nutritional status has an important impact on the quality of life as well as appropriate responses to drug therapy. Both diet-drug histories and counseling are needed. As new foods and drugs emerge and more self-medication is promoted, research in the prevention of food-drug interactions is needed.

ISSN:1363-1950    

出版商:OVID    

年代:2004

数据来源: OVID

摘要:

Purpose of reviewThe intake of water and electrolytes is inseparable from the ingestion of nutrients by normal or artificial means. Recent reports have agreed in criticizing the poor standards of practice and of training in the management of fluid and electrolyte balance, resulting in a large amount of avoidable morbidity, particularly in the elderly who are more vulnerable to fluctuations in body composition.Recent findingsAgeing is associated with impaired physiological reserve and a reduced ability to compensate for fluctuations in environmental conditions. These changes include reduced cardiac and renal reserve, making the elderly more vulnerable to changes in water and electrolyte gain or loss with a resulting increase in morbidity and mortality. The ability to cope with errors in prescriptions is correspondingly diminished. Dehydration is a common problem in nursing homes and in the community, due often to failures in detection and appropriate management. In many cases, the cause is iatrogenic due to diuretics or drugs which impair the intake of food and fluid. Salt and water overload, particularly in hospital patients, is also common and results in impaired recovery from surgery and increased perioperative mortality and morbidity. Hyponatraemia is also an important clinical problem in hospital and the community.SummaryBetter training in the detection, prevention and management of fluid and electrolyte imbalance is needed to reduce common and serious morbidity associated with this problem to which the elderly are especially prone, owing to their diminished physiological reserves and increased comorbidity.

ISSN:1363-1950    

出版商:OVID    

年代:2004

数据来源: OVID

摘要:

Purpose of reviewMuch of the research into nutrition and dementia focuses on end-of-life decisions about the ethics and efficacy of non-oral feeding. However, there are very many issues that arise long before that stage is reached. This review examines very recent papers that address the practical, day-to-day issues arising from the time that an individual with dementia needs help with eating and drinking.Recent findingsEvaluations of interventions aimed at increasing body weight demonstrate that weight gain is possible in dementia. Helping people with dementia to overcome problems with eating and drinking poses ethical and emotional problems for carers, particularly in the interpretation and management of apparent food refusal. Evidence-based practice can be incorporated into routine services for people with dementia and lead to improved nutritional care. Research needs to move away from the problems of providing adequate food in hospitals and care homes, to incorporating the views of people with dementia and their carers in the design of services in non-institutional settings.SummaryFew practical solutions to the nutritional problems of people with dementia have been presented in recent papers. Increased energy intake from food or supplements promotes weight gain, but effective interventions to overcome aversive behaviours have still not been described.

ISSN:1363-1950    

出版商:OVID    

年代:2004

数据来源: OVID

摘要:

Purpose of reviewThe purpose of this review is to provide a summary of the current state of knowledge concerning one of the intracellular signal transduction pathways through which amino acids, and in particular leucine, regulate the initiation phase of mRNA translation. The primary focus is on a protein kinase, termed the mammalian target of rapamycin (mTOR), that is a point of convergence between amino acid and growth factor signaling to mRNA translation and thereby to cell growth.Recent findingsUntil recently the pathway through which amino acids signal to mTOR was completely undefined. Several recent reports, however, describe the identification of proteins that modulate amino acid signaling through mTOR, that is the tuberous sclerosis complex proteins 1 and 2 and the Ras homolog enriched in brain (Rheb) protein. Tuberous sclerosis complex protein 2 is a GTPase activator protein for Rheb that is inhibited by amino acids, allowing Rheb to activate mTOR through a mechanism still to be delineated. In addition, two proteins that interact with mTOR to target it to two important substrates, eukaryotic initiation factor 4E binding protein 1 and ribosomal protein S6 kinase, have been identified. Both proteins, that is the regulatory associated protein of mTOR and G protein β-subunit-like protein, are required for optimal signaling through mTOR by amino acids.SummaryStudies reported in the past 18 months have greatly expanded our knowledge of one of the signaling pathways through which amino acids act to regulate mTOR and also the molecular interactions that mediate the interaction between mTOR and two downstream substrates, eukaryotic initiation factor 4E binding protein 1 and ribosomal protein S6 kinase.

ISSN:1363-1950    

出版商:OVID    

年代:2004

数据来源: OVID

摘要:

Purpose of reviewArginine metabolism has been a topic of intense interest over the past 15-20 years, primarily with regard to the role of arginine as the nitrogen donor for nitric oxide synthesis. However, other important aspects of arginine metabolism, such as arginine transport and arginine catabolism via the arginases, arginine decarboxylase or agmatinase, have been less well studied. The purpose of this review is to highlight recent studies on the urea cycle, agmatine metabolism, and the arginases.Recent findingsRecent advances include the cloning of complementary DNA encoding agmatinase,N-acetylglutamate synthetase, and proteins involved in mitochondrial arginine transport, as well as initial investigations of their regulation and tissue-specific expression. The most exciting results of studies in this area over the past year or so have indicated new roles for the arginases in health and disease, as a result of their effects on the synthesis of nitric oxide, proline, or polyamines, or on the expression of specific genes by their ability to limit the availability of free arginine.SummaryRecent studies have led to refinements in our understanding of the urea cycle. Agmatine metabolism is still largely a mystery, although the isolation of cloned cDNA for agmatinase and possibly also arginine decarboxylase should stimulate much needed investigations in this area. The most exciting findings in the field are coming from studies indicating new roles for the arginases in various diseases.

ISSN:1363-1950    

出版商:OVID    

年代:2004

数据来源: OVID

摘要:

Purpose of reviewThis review focuses on recent findings (June 2002-July 2003) on the topic of homocysteine, a sulfur amino acid associated with cardiovascular disease, and its metabolism in renal failure, a condition with a high prevalence of both hyperhomocysteinemia and cardiovascular disease.Recent findingsA large meta-analysis of prospective studies in the general population established that hyperhomocysteinemia is a risk factor for cardiovascular disease. The results of intervention trials, once available, will also have to be tested in a meta-analysis, because of predicted problems with their statistical power. In kidney patients, intervention trials, still in the recruiting stage, target transplant patients, because of their unique characteristics related to folate responsiveness. As for the cause of hyperhomocysteinemia, new findings show that in humans, renal metabolic extraction depends on renal plasma flow in the post-absorptive state. Folate absorption or interconversion seems not to be affected. Riboflavin is a determinant of plasma homocysteine levels in uraemia. The consequences of hyperhomocysteinemia in uraemia are DNA hypomethylation and altered gene expression.SummaryThe causes of hyperhomocysteinemia in renal failure are still not clear. However, the possibilities include defective renal or extrarenal metabolism as a result of uraemic toxicity. Renal plasma flow is important in homocysteine renal metabolism. Among the consequences of hyperhomocysteinemia in renal failure are impaired protein and DNA methylation, with an alteration in the allelic expression of genes regulated through methylation. Intervention trials are under way to test whether hyperhomocysteinemia is causally related to cardiovascular disease in this patient population.

ISSN:1363-1950    

出版商:OVID    

年代:2004

数据来源: OVID