摘要:

The 1993 ASPEN Research Workshop examined research and clinical advances in the study of human body composition. The workshop had two themes: (1) compartments of the body and their measurement, and (2) clinical applications of body composition measurements. There were 12 speakers of varied backgrounds who gave short lectures followed by panel discussions. Speakers explored the validity and potential uses of new body composition methodologies, including dual‐energy x‐ray absorptiometry, multiple frequency bioimpedance analysis, computerized axial tomography, magnetic resonance imaging, nuclear magnetic resonance spectroscopy, neutron inelastic scattering, and gamma‐ray resonance. The application of these methods to chronically and acutely ill hospitalized patients was described. The study of body composition is an emerging distinct research area within the broad study of human biology. This conference provided an overview of important new advances in the study of human body composition. (Journal of Parenteral and Enteral Nutrition18:91–103, 1994)

ISSN:0148-6071    

DOI:10.1177/014860719401800291

出版商:SAGE Publications    

年代:1994

数据来源: WILEY

摘要:

The effects of a thiamine‐deficient diet on plasma and tissue vitamin concentrations and on whole‐body glucose metabolism were assessed. Male Sprague‐Dawley rats (175 to 200 g body weight) fed a thiamine‐deficient (TD) or nutritionally complete purified diet were used for plasma thiamine mononitrate and monophosphate and for red blood cell and tissue thiamine pyrophosphate (TPP) determinations weekly for up to 5 weeks. Additional rats were used for assessment of basal glucose kinetics by using a primed constant infusion of [3‐3H]glucose. Plasma thiamine mononitrate levels decreased 60% at 1 week and were undetectable after 5 weeks on the diet. Plasma thiamine monophosphate decreased 80% after 1 week on the TD diet, and levels were undetectable after 4 weeks on the diet. Red blood cell TPP in the TD group decreased progressively with time: 54% at 1 week, 86% at 3 weeks, and 92% at 5 weeks. At 1 and 4 weeks, the decrease in tissue TPP was significant in the liver (65% and 89%, respectively), gut (52% and 94%, respectively), spleen (40% and 60%, respectively), and skeletal muscle (37% and 76%, respectively), with the brain (7% and 84%, respectively) showing the slowest initial rate of depletion. The TD diet did not alter plasma glucose concentrations, but it increased plasma lactate by 75% and plasma pyruvate by 50% to 75%. Rates of hepatic glucose production and peripheral glucose utilization were not different between the control and TD rats at 2 weeks, but they were 25% higher in the TD rats after 6 weeks on the diet. Plasma hormone concentrations were not different between the control and TD animals at 2 weeks. However, after 6 weeks on the diet, plasma insulin levels were 37% lower in the TD group, and glucagon and corticosterone levels were 85% to 97% higher than in the control animals. In general, these changes in whole‐body glucose flux induced by the TD diet could not be explained simply by the reduction in food consumption in the deficient animals In summary, TD resulted in (1) marked reductions in plasma thiamine levels, (2) a progressive decrease in red blood cell TPP content that paralleled that seen for both thiamine monophosphate and TPP in most peripheral tissues, and (3) multiple changes in whole‐body carbohydrate metabolism and glucoregulatory hormone concentrations. These changes were documented before any neurologic manifestations of a TD state. (Journal of Parenteral and Enteral Nutrition18:104–111, 1993)

ISSN:0148-6071    

DOI:10.1177/0148607194018002104

出版商:SAGE Publications    

年代:1994

数据来源: WILEY

摘要:

We explored the effects of plasma‐like conditions on hydrolysis of medium‐chain triglyceride (MCT) and long‐chain triglyceride (LCT) emulsions at different mixing ratios and the effect of the physical method of mixing on lipoprotein lipase hydrolysis of mixed emulsions in vitro. Mixed emulsions with two different mixing ratios, 50% MCTs with 50% LCTs and 70% MCTs with 30% LCTs by weight, were studied. Emulsions containing both MCT and LCT oils blended in the same emulsion particle were compared with mixtures of separate pure MCT emulsion particles and pure LCT particles. MCT hydrolysis was always greater than LCT hydrolysis. In a plasma‐free tris(hydroxymethyl)aminomethane‐albumin buffer at pH 8.5, the physical method of mixing had substantial effects on hydrolysis; blended emulsions of MCTs and LCTs were hydrolyzed better than separate mixes of pure MCT and pure LCT particles, ie, more total free fatty acids were released. In plasma‐free systems, there were no differences in rates of hydrolysis of LCTs or MCTs (as individual triglycerides) between the two different mixing ratios of 50:50 and 70:30. However, the presence of plasma markedly diminished the differences in hydrolysis between blendedvsseparately mixed emulsions at pH 7.4. Also, in plasma‐like incubation buffer, the rates of hydrolysis of MCTs and LCTs in emulsions with 50:50 or 70:30 MCT to LCT ratios reflected the respective amounts of MCT and LCTs in the emulsions. These data suggest that there are no significant differences in hydrolysis between blended and separately mixed MCT and LCT emulsions in plasma at pH 7.4, and that the rate of release of total free fatty acids during emulsion hydrolysis is largely dependent on the initial amount of MCT in the mixture. (Journal of Parenteral and Enteral Nutrition18:112–118, 1994)

ISSN:0148-6071    

DOI:10.1177/0148607194018002112

出版商:SAGE Publications    

年代:1994

数据来源: WILEY

摘要:

The intravenous infusion of amino acid solutions has been associated with cholestatic liver injury in hospitalized patients and in laboratory animals. In the isolated rat liver, we recently showed that the acute decrease in bile flow, previously reported by other investigators, is dose related, reversible, and associated with dose‐related increases in total biliary amino acid concentrations. In the present study, we characterized the effects of graded infusions of amino acid solutions, with and without taurocholate, on biliary secretion of individual amino acids and glutathione, an important regulator of bile flow. Livers from young adult male rats were perfused with an amino acid solution for 1 hour and allowed to recover for 30 minutes. Infusion of the amino acid solution was associated with dose‐related increases in biliary concentrations of most amino acids included in the amino acid solution. Infusion of amino acid solutions resulted in a decreased bile/perfusate ratio of most amino acids, which were secreted into bile in amounts approximating their calculated uptake from the infusate. The inclusion of taurocholate in the infusate was associated with lower biliary concentrations of each individual amino acid and significant decreases in biliary total, reduced, and oxidized glutathione. Further investigation of the relationship between these changes in biliary amino acids and glutathione concentrations and the cholestasis associated with infusion of amino acid solutions may provide insights into the mechanism by which amino acids induce such cholestasis. (Journal of Parenteral and Enteral Nutrition18:119–127, 1994)

ISSN:0148-6071    

DOI:10.1177/0148607194018002119

出版商:SAGE Publications    

年代:1994

数据来源: WILEY

摘要:

Glutamine is essential for the function of lymphocytes and macrophages, where it serves, among other things, as a source of energy. Little information is available concerning the fuel that polymorphonuclear cells use for their metabolic and bactericidal functions. It was the purpose of this study to determine whether glutamine would enhance thein vitrobactericidal function of normal neutrophils and whether the amino acid would restore the observed impaired function in burn patients to or above the normal level. Twelve burn patients with total body surface area burns ranging from 32% to 87% were studied. At various postburn times, neutrophils were isolated and their ability to killStaphylococcus aureusin the presence and absence of glutamine was determined and compared with that in normal subjects. Glutamine enhanced the bactericidal function of normal neutrophils. In every patient, at all but two postburn times, glutamine caused an improvement in the observed abnormal neutrophil bactericidal function and often restored it to or slightly above the normal level. Glutamine had no effect on the expression of C3b receptors (CR1 or CD35) or on phagocytosis by the cells. This study confirms the beneficial effects of glutamine in at least one arm of the immune system and adds evidence for the possible advantage of including this amino acid in the diets of burn and other trauma patients. (Journal of Parenteral and Enteral Nutrition18:128–133, 1994)

ISSN:0148-6071    

DOI:10.1177/0148607194018002128

出版商:SAGE Publications    

年代:1994

数据来源: WILEY

摘要:

To determine the hydrolysis rate of medium‐chain triglycerides (MCTs) to medium‐chain free fatty acids (MCFAs) and the disposition rate of MCFAs, five healthy volunteers (H) and eight surgically stressed patients (S) received 0.5 mL of Lipofundin 20% per kilogram body weight as an intravenous bolus. Serum MCTs (C8 and C10) and MCFAs were measured by high‐performance liquid chromatography during the 120 minutes postinjection. A linear two‐compartment model was found to be descriptive and robust: the apparent volumes of distribution were found to be similar in healthy and surgical subjects for both MCTs and MCFAs. The first‐order transformation rate constant (hydrolysis) from MCTs to MCFAs was not significantly different between the H and S groups (overall 0.112 ± 0.022/min, C8; 0.078 ± 0.020/min, C10). The rate constant for tissue MCFA uptake from plasma was significantly different between S and H subjects both for C10 alone (H: 0.0337 ± 0.0078; S: 0.1194 ± 0.0240;p=.020) and for C8 and C10 together (H: 0.0382 ± 0.0054; S: 0.1012 ± 0.0168;p=.008), whereas it failed to attain significance when C8 alone was considered (H: 0.047 ± 0.0077; S: 0.0829 ± 0.0230;p=.210). These results show that use of MCTs is increased in surgical patients because of enhanced tissue uptake of the corresponding free fatty acids, whereas there does not seem to be an increase of MCT hydrolysis in response to acute disease. This would indicate that the stressed patient is in fact able to effectively use this alternative lipid substrate in the face of increased metabolic demand. (Journal of Parenteral and Enteral Nutrition18:134–140, 1994)

ISSN:0148-6071    

DOI:10.1177/0148607194018002134

出版商:SAGE Publications    

年代:1994

数据来源: WILEY

摘要:

The effects of an elemental diet on lymphocyte transport in intestinal lymph and immune responses of gut‐associated lymphoid tissue were investigated in rats. The control animals were fed a conventional diet. After 4 week of feeding, the total calorie intake and body weight gain showed no differences between the two groups. The number and total area of Peyer's patches and the ratio of height of villi to height of crypt showed no significant differences between the two groups. The rate of lymph flow in intestinal lymphatics showed no significant change in treated animals compared with the control rats. However, an elemental diet induced a significant decrease in lymphocyte flux in intestinal lymphatics compared with that in control rats. Lymphocyte subsets in intestinal lymph revealed a significant decrease in CD3‐positive cells, especially CD4‐positive cells in the elemental diet‐treated group. A significant decrease in the number of immunoglobulin A‐containing cells and a decreased CD4/CD8 ratio in T‐cell subsets were observed in the lamina propria of ileal mucosa in the elemental diet‐treated group by morphometric analysis in the immunohistochemical study. Specific antibody‐secreting cells in intestinal lymph were also investigated after rats were intraduodenally primed with cholera toxin and challenged with the same toxin after an interval of 2 weeks. No significant difference was seen between the two groups in any of the numbers of anti‐cholera toxin immunoglobulin‐secreting cells in any immunoglobulin A, immunoglobulin G, or immunoglobulin M class as determined by the enzyme‐linked immunospot assay. These results suggest that the elemental diet we used might have an inhibitory effect on several aspects of the mucosal immunologic system of the gut without significant reduction in its ability to produce specific antibodies. (Journal of Parenteral and Enteral Nutrition18:141–147, 1994)

ISSN:0148-6071    

DOI:10.1177/0148607194018002141

出版商:SAGE Publications    

年代:1994

数据来源: WILEY

摘要:

The development of cachexia may complicate cancer therapy, yet controversy exists concerning its nutritional management. For example, use of total parenteral nutrition (TPN) may not be appropriate because of gut atrophy, possible stimulation of tumor growth, and lack of total host protein repletion. In the present experiment, host and tumor responses were compared after identical parenteral or enteral nutritional supplementation (EN). Eighteen days after subcutaneous inoculation of adult male Fischer‐344 rats with fresh methylcholanthrene‐induced sarcoma (tumor‐bearing [TB] rats), catheters were placed into either the external jugular vein or the stomach. Four days later, rats were started on an 11‐day course of either TPN or EN with a Freamine‐III‐based formula (amino acids = 6%, dextrose = 21.5%, lipid = 1.5%). When the rats were killed, there was no difference in tumor weight between the various TB groups. Carcass weight was increased significantly in both the TB‐TPN and TB‐EN groups, and there was an elevation in gastrocnemius protein content in both groups compared with the TB‐rat food group. Small intestine protein was preserved in the TB‐EN group to the level observed in the control‐rat food animals. Total lipids in the liver were increased in both TB‐TPN and TB‐EN groups; however, the magnitude of the increase was less in the TB‐EN animals. Neither treatment resulted in complete protein repletion of tumor‐bearing rats. EN may be more appropriate than TPN in that gut mass is preserved. The maintenance of gut mucosa may prove to be beneficial in the treatment of the depleted, immunocompromised, and metabolically stressed host. (Journal of Parenteral and Enteral Nutrition18:148–153, 1994)

ISSN:0148-6071    

DOI:10.1177/0148607194018002148

出版商:SAGE Publications    

年代:1994

数据来源: WILEY

摘要:

Postpyloric feedings are a widely practiced form of enteral nutrition. We prospectively randomized two groups of hospital patients to receive a standard feeding tube or a feeding tube that uses a pH sensor to facilitate postpyloric placement and compared placement speed and accuracy, displacement detection, and costs for the two groups. Thirty‐nine patients were randomized, with 20 receiving a pH sensor feeding tube and 19 an identical non‐pH sensor feeding tube. An x‐ray of the kidneys, ureter, and bladder was taken at 1, 6, and 48 hours after placement in both groups. Separate cost‐benefit analyses were done by using retrospective chart review of costs for a separate 20‐patient standard feeding tube group and calculated costs for a 20‐patient hypothetical pH sensor group. At 1 hour, the duodenum was reached in 53% of the pH sensor feeding tube patients and 45% of the standard feeding tube patients (the difference was not significant). At 48 hours, 93% of the pH sensor feeding tubes reached the duodenumvs67% of the standard feeding tubes (p<.08). Thirty percent of the pH sensor patients had an initial gastric pH ≥4, negating pH sensor benefit in tube placement. In the remaining 70% of the patients, placement with the pH sensor had a 100% specificity compared with the x‐ray of the kidneys, ureter, and bladder. Displacement was easily detected with routine pH monitoring in three of the pH sensor feeding tube patients and corrected. It was detected in two standard feeding tube patients, one of whom aspirated. Cost‐benefit analysis incorporating the above findings showed a cost savings of $81.00 per patient for the pH sensor feeding tube, more than the cost of the tube. Thus, pH sensor feeding tubes may obviate the need for confirmatory x‐rays in patients without hypochlorhydria, resulting in potential significant savings. (Journal of Parenteral and Enteral Nutrition18:154–158, 1994)

ISSN:0148-6071    

DOI:10.1177/0148607194018002154

出版商:SAGE Publications    

年代:1994

数据来源: WILEY

摘要:

We have previously shown that parenteral and certain elemental diets promote bacterial translocation and that this diet‐induced bacterial translocation can be prevented by the provision of bulk‐forming dietary fiber. The goal of the current study was to test the hypothesis that fiber's protective effect on diet‐induced bacterial translocation was mediated by trophic gut hormones. This hypothesis was tested by using bombesin (which stimulates gut hormone release) or the somatostatin analog Sandostatin (which inhibits gut hormone release) to modulate gut hormone release in rats receiving rat food, intravenous total parenteral nutrition, or an elemental diet. Both bombesin and fiber were effective in preventing elemental diet‐induced bacterial translocation, whereas octreotide acetate abrogated the protective effect of fiber. Bombesin was also effective in limiting bacterial translocation in parenterally fed rats. Although both enteral (elemental diet) and parenteral diet‐induced bacterial translocation were associated with cecal bacterial overgrowth, loss of small‐bowel weight, and loss of mucosal protein content, none of these factors seemed to be primarily responsible for bacterial translocation. Because bombesin decreased the incidence of villous injury in the elemental diet‐fed rats and decreased the incidence of villous injury and prevented loss of intestinal barrier function to horseradish peroxidase in the parenterally fed rats, it is possible that bombesin exerted its protective effect by limiting mucosal injury and preserving barrier function. (Journal of Parenteral and Enteral Nutrition18:159–166, 1994)

ISSN:0148-6071    

DOI:10.1177/0148607194018002159

出版商:SAGE Publications    

年代:1994

数据来源: WILEY