摘要:

Metabolic adaptation to pregnancy in humans and animals is aimed at provision of nutrients for the growth and energy metabolism of the growing conceptus, as well as for the mother. Kinetic studies in human pregnancy have shown that fluxes of energy-yielding substrates, i.e. glucose, fatty acids and glycerol, increase in parallel with the increasing demands of the fetus and the mother. Resistance to insulin action, measured by hyperinsulinemic euglycemic clamp, appears early in gestation and is correlated with the infant's birth weight. Adaptive responses in nitrogen metabolism, decreased plasma urea concentration and decreased rate of urea synthesis, are apparent early in pregnancy, much before any significant increase in fetal demands. Recent studies of branched chain aminoacid (leucine) kinetics show a lower flux of leucine nitrogen and an unchanged flux of leucine carbon in gestation. A linear correlation between rate of deamination of leucine and rate of urea synthesis was observed in pregnant women. It is speculated that decreased anaplerotic carbon flux in the tricarboxylic acid cycle, as a consequence of insulin resistance, may have an important role in the down-regulation of transamination of leucine during pregnancy, and may contribute to the conservation and accretion of nitrogen by the mother and the fetus.

ISSN:1363-1950    

出版商:OVID    

年代:1999

数据来源: OVID

ISSN:1363-1950    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Clinical and basic research continues to expand our understanding of the complex pathogenesis of inflammatory bowel diseases. The potential roles played by fatty acid intake, serum leptin, and nitric oxide in the promotion of intestinal inflammation in Crohn's disease and ulcerative colitis will be reviewed. In addition, important advances in the areas of bone disease, vitamin deficiency, growth failure, and home parenteral nutrition will be discussed.

ISSN:1363-1950    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

In the past year, some relevant papers on the mechanisms of malnutrition in cirrhosis have been published. Studies investigating the metabolic destiny of leucine after protein breakdown, which have contributed to a better understanding of the pathogenesis of muscle wasting and fat depletion in these patients, deserve particular mention. Also, the demonstration that chronically reducing hyperinsulinaemia in cirrhosis is able to improve insulin sensitivity opens novel pathogenic and therapeutic perspectives for such a metabolic derangement in these patients. Other papers dealt with unsaturated lipids, lipoperoxidation and antioxidants in chronic liver disease. However, randomized trials on parenteral or enteral nutrition in cirrhosis and liver transplantation are missing.

ISSN:1363-1950    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

The profound impact of nutrition and nutritional support on the development and clinical outcome of gastrointestinal cancer is undeniable. However, scientific investigation into this area is recent, and many questions remain unanswered. While the importance of ‘good nutrition’ is unchallenged, details relating to which patients should receive nutritional support, when they should receive it, and what type of support they should receive are not known. Recent prospective randomized clinical trials and metanalysis have provided conflicting results. This review summarizes the results of the published studies that have addressed these issues, and provides specifics regarding the current role of nutritional support in clinical care, and the prospects for future research.

ISSN:1363-1950    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Home artificial nutrition is a mature technology that has been with us for over a quarter of a century. Its use appears to be more widespread in the USA than in other western countries. Issues of outcome, ethics, and quality of life are increasingly important. Complications continue to be reported, some newly recognized and some that we must continually relearn.

ISSN:1363-1950    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

This article reviews the current literary data on the role of conservative supportive treatment for acute pancreatitis, with special emphasis on parenteral and enteral nutrition. Despite the fact that the indications for both methods have been discussed, defined and widely accepted in recent years, enteral nutrition is currently the focus of recent clinical investigations for use in acute pancreatitis.

ISSN:1363-1950    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Abnormal colonization, gut-origin infections, and bacterial translocation are all signs of gut dysfunction that may be implicated in the pathogenesis of multiple organ dysfunction syndrome (MODS). This review summarizes and updates relevant experimental and clinical data that have attempted to correlate these phenomena with the development of MODS and to answer whether or not the gut is the ‘motor’ of MODS. The presented data suggest that, in some patients, gut dysfunction may precede the development of MODS. However, in most patients, this relationship is less obvious. The gut may still be one of the motors of MODS; however, it does not appear that this motor is fueled by the systemic spread of bacteria. Bacteria may play a role on a local gut-associated level in initiating and perpetuating the production of local inflammatory mediators that may produce distant organ injury.

ISSN:1363-1950    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

The normal indigenous flora of the human gastrointestinal tract comprises a remarkably complex yet stable colony of more than 400 separate species, living in a symbiotic relationship with the human host. Stability of that flora is accomplished by multiple mechanisms including gastric acidity, gut motility, bile, products of immune cells in the gut epithelium, and competition between microorganisms for nutrients and intestinal binding sites. The indigenous flora influences multiple aspects of physiologic homeostasis and forms a key component of normal host defenses against infection by exogenous pathogens. Critical illness is associated with striking changes in patterns of microbial colonization, best described in the oropharynx and upper gastrointestinal tract. Pathological colonization occurs with the same species that is predominate in nosocomial infections, and descriptive studies suggest that such colonization is a risk factor for infection. Moreover, prophylactic measures that prevent pathological gut colonization in experimental circumstances reduce rates of nosocomial infection in critically ill patients and, in the case of selective decontamination of the digestive tract, reduce mortality risk. Conventional approaches to infectious diseases have conceptualized microorganisms as inimical and focused on eradicating them as rapidly and fully as possible. Insights from the study of critically ill patients suggest that that relationship is better understood as a symbiotic one and that preservation, rather than elimination, of the indigenous flora provides the greatest promise of clinical benefit to this vulnerable population.

ISSN:1363-1950    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Interesting advances occurred recently in nutrient absorption. Kinetics of triacylglycerol appearance in endoplasmic reticulum, Golgi apparatus, and lymph support the hypothesis that endoplasmic reticulum-to-Golgi transport is rate-limiting for lipid absorption. Apolipoprotein B does not appear necessary for initial formation of chylomicron-sized lipid particles in the endoplasmic reticulum, but rather for their movement out of the endoplasmic reticulum and to the Golgi. If peptides are protected from luminal proteolysis by fatty acylation, or if a nonpeptide drug, acyclovir, is esterified with valine to enhance bioavailability, the peptides nevertheless are absorbed by peptide transporters. Experimental conditions needed to use human ileal mucosa forin vitroabsorption studies are described. Intestinal mucosa contains leptin receptors, and leptin inhibits galactose absorption, suggesting a new site for leptin's modulation of body mass. The enhancer element for theapoBgene is located much farther from its structural gene in the intestine than in the liver.

ISSN:1363-1950    

出版商:OVID    

年代:1999

数据来源: OVID