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:

Increased use of intravenous in-line filtration for all-in-one admixtures has been one of several recent stimuli to developing methods for assessing the stability of parenteral nutrition regimens. Admixture formulations previously deemed to be ‘stable' have caused filter blockage and this requires urgent reconsideration of the definitions of physical emulsion stability. The new technique of acoustic attenuation spectroscopy has been evaluated as another means of assessing physical stability of emulsions, and some of the newer techniques have been further applied to provide additional insight into the effects of light and oxygen. There has also been additional work on trace element contamination and changes in trace element concentrations on storage. Overall this review period has been one of evolution rather than revolution.

ISSN:1363-1950    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

Malnutrition is a serious problem, and malabsorption of nutrients is believed to be partially responsible for its prevalence. A wide variety of innovative methods have been developed to study gastrointestinal transport function. Some of the first research into gastrointestinal function was conducted in the 1700’s with animal and human models. Methodological advancements continue to allow scientists to innovatively assess gastrointestinal function in animal models, cellular preparations and clinical settings. For this update, the methods are divided intoin vivo,ex vivo, isolated cells and membranes, and molecular biology approaches. Thein vivomethods discussed include animal and human models to measure nutrient disappearance, catheterized animal models, models with isolated intestinal segments, and a new procedure for sampling luminal fluid from patients. Theex vivoapproaches discussed obtain measurements with intact tissue, such as the everted sleeves method and Ussing chambers. The utility of novel cellular preparations, membrane fractionation procedures and various molecular biology techniques is included. Various aspects of these methods are evaluated to provide a detailed overview of recent methodological developments.

ISSN:1363-1950    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

The success of nasoenteral nutrition support can be limited by intestinal impairment. In particular, reduced absorptive area, mucosal atrophy and abnormal motility may reduce absorption of macronutrients and micronutrients, and diarrhoea remains a commonly encountered complication. We review how basic physiological techniques can be used to investigate such pathophysiology. Lumenal nutrients control mucosal growth, expression of mucosal transporters and regional gut motility. Cell biology techniques now complement classical intestinal perfusion methods in determining the ‘safety factor’ of excess absorptive capacity. The controversial role of the sodium-glucose linked transporter in dietary glucose assimilation is described in terms of its control, its true function and its role in uptake of other solutes. Techniques that involve brush-border membrane vesicles, Caco-2 cells, mucosal immunohistochemistry and gene expression probes are described. Together, these techniques describe a picture of an organ with remarkable ability to maintain digestive and absorptive function in response to a wide variety of nutritional intakes, often in the face of inflammatory illness.

ISSN:1363-1950    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

Scientists have long been interested in measuring the effects of different stimuli on protein expression and metabolism. Analytical methods are being developed for the automated separation, identification, and quantitation of all of the proteins within the cell. Soon, investigators will be able to observe the effects of an experiment on every protein (as opposed to a selected few). This review presents a discussion of recent technological advances in proteomics in addition to exploring current methodological limitations.

ISSN:1363-1950    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

Body-composition methodologies rely on assumptions that are not constant across ethnic groups. The consequence is that the methods used need to be population specific to guarantee unbiased conclusions. Alternatively, assumption-free methods such as chemical multiple-compartment models or scanning techniques should be used. Adequate and unbiased scientific data on body fat among ethnic population groups are necessary for a better understanding of the aetiology of obesity and its co-morbidities. The World Health Organization cut-off points for underweight, overweight, obesity and fat distribution, now universally defined, may need revision because the relationship between body mass index and body composition, and between indices of fat distribution and the actual amount of visceral fat, differ across ethnic groups. The need for ethnically specific cut-off points for obesity and fat distribution is substantiated, for example, by elevated disease risks at low levels of body mass index in several populations. Properly designed and conducted studies are needed to obtain unbiased information on these topics.

ISSN:1363-1950    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

Polyamines are ubiquitous cell components for growth. They play an important role in cell proliferation, cell growth and synthesis of protein and nucleic acids. Cells that are stimulated to reproduce demonstrated early increases in biosynthetic enzymes involved in polyamine synthesis and subsequent elevations in polyamine levels. Extracellular fluid polyamine concentrations that reflect the intracellular events may be useful as rapid indicators of therapy in disorders which involve altered cell growth. More complex analytical approaches are required to isolate, identify and quantitate these polyamines. Most of the methods require an extraction procedure to remove interfering amino acid derivatives. Daily monitoring of plasma and urine polyamine levels in many pathological states may provide a non-invasive biochemical marker of the existing disease activity or response to therapy or to screen for drug efficacy. Automated high-performance liquid chromatography, with post or pre-column derivatization and fluorescence or electrochemical detection is frequently used for the simultaneous quantitation of picomolar quantities of polyamines. Recently, a new immuno-cytochemical model system incorporating an enzyme-linked immunosorbent assay for specific polyamines has been developed. The increasing momentum of basic science information in the polyamine discipline may lead clinicians to regard polyamines, their metabolites and antimetabolites as sources of effective treatment.

ISSN:1363-1950    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

Acute and chronic diseases are frequently characterized by alterations in energy metabolism that influence nutritional requirements and clinical care. Knowledge of the effect of disease on daily energy expenditure and its components is fundamental to understanding the impact of the disease process on energy balance. To obtain this information, energy expenditure data are often compared between healthy and diseased individuals. This review focuses on the statistical and physiological issues related to comparing energy expenditure data among individuals who differ in body size and composition.

ISSN:1363-1950    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

Insulin-like growth factor-I circulates in serum either in free form or bound to insulin-like growth factor-binding proteins that modulate its bioavailability. Insulin-like growth factor-binding proteins interfere with insulin-like growth factor-I assay, which remains technically difficult. Many assays have been developed, but their results are somewhat discordant. The choice of separation method, standard and tracer considerably influences the results. The circulating concentration of insulin-like growth factor-I, however, is clearly dependent on nutritional status, and total levels are a valuable marker of nutritional status. The clinical utility of free insulin-like growth factor-I assay and simultaneous assay, in the same sample, of total insulin-like growth factor-I and its binding proteins (reflecting the bioavailable insulin-like growth factor-I fraction), remains to be evaluated.

ISSN:1363-1950    

出版商:OVID    

年代:2001

数据来源: OVID