ISSN:1363-1950    

出版商:OVID    

年代:2003

数据来源: OVID

ISSN:1363-1950    

出版商:OVID    

年代:2003

数据来源: OVID

ISSN:1363-1950    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

Purpose of reviewChanges in body composition accompany and predict medical and surgical risk; interventions may be considered. Aging affects body composition, particularly in reduction of the body cell mass.Recent findingsThe molecular biology of aging has become an active frontier of research in the past 30 years, with acceleration in the past decade. A review of the toxicities of reactive oxygen and nitrogen species, especially at the mitochondria, can now be studied at the molecular, genetic, and proteomic scales, in individual cell components and systems, with major implications for patient management, for planning therapeutic interventions, and for predicting future age spans.SummaryThe intersections between the clinical fields of endocrinology, nuclear medicine/radiology, and geriatrics, with the more fundamental fields of physiology, molecular biology, genetics, and proteomics are indicated.

ISSN:1363-1950    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

Purpose of reviewDuring ageing there may be the onset of a chronic inflammatory state. This review examines the underlying causes of this phenomenon and the role that genotype plays in its intensity.Recent findingsThere are predisposing factors for the chronic inflammation that occurs during ageing. These include increased oxidative stress, a decrease in ovarian function, a decrease in stress-induced glucocorticoid sensitivity of pro-inflammatory cytokine production in men, and an increased incidence of asymptomatic bacteriuria. Obesity induces chronic inflammation. Inflammation is a key factor in the progressive loss of lean tissue and impaired immune function observed in ageing. Polymorphisms in the promoter regions of pro- and anti-inflammatory cytokine genes influence the level of cytokine production and the ageing process. Thus, a genotype for high pro-inflammatory cytokine production results in high cytokine production and may accelerate the rate of tissue loss. Conversely, polymorphisms in the genes for anti-inflammatory cytokines may result in a slowing of tissue loss. In the healthy aged male population, the former polymorphisms are under-represented and the latter over-represented, indicating a genetically determined survival advantage in maintaining inflammation at a low level. Nutrients with anti-inflammatory properties, such as vitamin E andn-3 polyunsaturated fatty acid, may reduce the level of chronic inflammation and thereby ameliorate tissue and functional loss during ageing. New evidence suggests that, for the latter nutrient, gene-nutrient interactions occur that alter the effectiveness of dietary therapy.SummaryAgeing is associated with increased levels of chronic inflammation. This plays a major role in the decline in immune function and lean body mass. Anti-inflammatory nutrient therapy may slow the rate of decline. The pro- and anti-inflammatory cytokine genotype is linked negatively and positively, respectively, with life-span, because of its influence on inflammation.

ISSN:1363-1950    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

Purpose of reviewLongevity with good health and long-term survival in space are two of the many challenges that scientists face in the twenty-first century. Ageing and life in space are both associated with undesirable effects on normal physiological processes. This review will outline how the endocrine, metabolic, immune and musculoskeletal systems are affected by microgravity and ageing, drawing analogies between the observed changes in an attempt to highlight common mechanisms.Recent findingsMild hypothyroidism, increased stress hormones (mainly catecholamines), decreased sex steroids, insulin resistance, impaired anabolic response to food intake, anorexia, altered mitochondrial function and systemic inflammatory response are common features of both ageing and microgravity. Both conditions lead to progressive bone and muscle atrophy, compromising mobility and the ability to perform essential daily tasks. In skeletal muscle, both ageing and space flight lead to weakness from whole muscle to single fibre level, accompanied by marked alterations in muscle architecture and in tendon mechanical properties.SummaryWhat makes microgravity an interesting and unique tool for gerontologists is that many space-related physiological changes resemble those observed during ageing, but are more or less quickly restored after re-entry, thus allowing the biology of ageing to be investigated both ways, not only during its development but also during recovery.

ISSN:1363-1950    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

Purpose of reviewThe subject of gastrointestinal disorders in the elderly is timely and important because of the demographic reality that soon over 20% of our population will be older than 65 years of age, utilizing perhaps 50% of our total healthcare costs. The purpose of this review is to draw attention to some areas of clinical information that point in the direction of better clinical care for the elderly. Medicine is finally advancing from the era when most symptoms in older patients were ascribed to the aging process itself. Indeed, within gastroenterology there are few changes that occur inevitably as part of aging.Recent findingsProgress has been made in several areas of gastrointestinal pathophysiology. These include: the pathophysiology of swallowing and evacuation disorders and the beginning of the application of techniques derived from physiological studies to improve function; recognizing the importance of reflux esophagitis and its complications and improving treatment; understanding the importance of disorders of malabsorption and their impact upon nutrition in the elderly; major issues in the diagnosis and management of inflammatory bowel disease in this age group; and approaches to the prevention and treatment of gastrointestinal cancer, particularly colorectal cancer.SummaryAs we pay more attention to these areas and encourage clinical research we expect to improve the treatment of older patients with these diseases and to reduce the burden of morbidity in this population.

ISSN:1363-1950    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

Purpose of reviewThere is increased evidence of several impaired gastrointestinal functions with ageing. In the elderly, however, most gastrointestinal functions remain relatively intact because of the large reserve capacity of the intestine and the great secretion capacity of the pancreas. This review will focus on changes in gut microflora observed in the elderly and on the potential benefit of probiotics in this population.Recent findingsRecent studies suggest that age affects the intestinal microflora with a decrease in anaerobes and bifidobacteria population and an increase in enterobacteria. These changes and the reduced intestinal immunity of the aged may favour gastrointestinal infections that are frequent in the elderly.Clostridium difficile-associated diarrhoea, one of the most common nosocomial infections in the elderly, has a profound effect on morbidity, mortality and health costs. Probiotics may have interesting positive effects on intestinal function, and the efficacy of treatment withLactobacilliandSaccharomyces boulardiiinClostridium difficile-associated diarrhoea has been well established in a recent meta-analysis. Studies performed in healthy elderly patients suggest that diet supplementation with probiotics may reduce the impaired immunity associated with ageing.SummaryImportant changes in intestinal microflora of the elderly have recently been demonstrated and may have important clinical consequences. Further studies should be conducted to determine if the consumption of probiotics is associated with a lower infection rate and a higher effectiveness of vaccines.

ISSN:1363-1950    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

Purpose of reviewChanges in hormone secretion, tissue perfusion, oxygen availability, energy-protein intake, free amino acid pattern, hydration state, acid-base balance as well as activation of the systemic inflammatory response may affect protein synthesis and degradation. The overall purpose of this review is to describe how these factors may interact to change protein turnover in the different directions seen in kinetic studies in humans.Recent findingsEvidence indicates that,in vivo, changes of protein synthesis and degradation are strictly related. When protein synthesis is primarily suppressed, protein degradation is found to be unchanged or even slightly decreased. When protein degradation is primarily accelerated, the rate of synthesis is unchanged or even increased. Chronic disease states can, therefore, be characterized either by decreased or accelerated protein turnover. Apparent discrepancies among various studies in chronic uraemia, liver cirrhosis, chronic obstructive pulmonary disease and cancer may stem from the fact that the pathogenesis of protein metabolism abnormalities is multifactorial. When the effects of inflammatory mediators and stress hormones start overwhelming factors that tend to decrease protein synthesis and turnover (decreased protein-energy intake, physical activity, tissue oxygen delivery, leucine levels, etc.), the rate of protein degradation and turnover may increase.SummaryLow-protein turnover conditions are usually associated with the adequate sparing of body proteins, whereas in high-protein turnover conditions protein loss may proceed at a faster rate. Nonetheless, impaired recovery from acute complications and the reduced renewal of damaged and toxic proteins are potential undesired consequences of low-protein turnover.

ISSN:1363-1950    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

Purpose of reviewThe primary aim of this review is to highlight recent advances in techniques available for assessing collagen turnover, particularly in relation to the diagnosis and management of bone disorders. As collagen is the major protein constituent of bone, its metabolites form the basis of most of the biochemical markers, but their efficacy needs to be viewed in the context of other non-collagenous markers, for which methodology is also advancing rapidly.Recent findingsNew markers of bone metabolism have been developed utilising the age-dependent isomerisation and racemisation of aspartyl residues at the C-terminal end of collagen. These methods allow measurement of the ratio between newly synthesised and mature collagen: this ratio appears to provide a novel indicator of the fracture risk for osteoporosis. Other studies have led to an improved understanding of biological variability, particularly in relation to the effects of feeding. Bone resorption assays have been applied to a wide range of diseases and have been especially useful in monitoring the efficacy of novel therapies.SummaryNew assays have been developed to facilitate better monitoring of collagen metabolism in bone diseases. A more complete understanding of biological variability, particularly the effects of feeding, have led to improved clinical applicability of these assays in detecting disease and monitoring therapy. Part of the future challenge, however, is to ensure that commercial assay developments keep pace with clinical expectations.

ISSN:1363-1950    

出版商:OVID    

年代:2003

数据来源: OVID