ISSN:0148-6071    

DOI:10.1177/014860719501900101

出版商:SAGE Publications    

年代:1995

数据来源: WILEY

ISSN:0148-6071    

DOI:10.1177/014860719501900103

出版商:SAGE Publications    

年代:1995

数据来源: WILEY

摘要:

Background: The use of medium‐chain triglycerides in diets is limited by the frequent occurrence of diarrhea or crampy abdominal pain. Because these symptoms may result from an accelerated transit time induced by medium‐chain triglycerides, we investigated the effect of equimolar amounts of long‐chain triglycerides and medium‐chain triglycerides on small‐bowel transit time in 10 healthy subjects.Methods: Small‐bowel transit time was measured by the lactulose hydrogen breath test after intraduodenal administration of lactulose.Results: Intraduodenal administration of 20 mmol of long‐chain triglycerides per hour for 90 minutes did not alter small‐bowel transit time compared with control (77 ± 11 minutesvs77 ± 10 minutes, respectively), whereas intraduodenal infusion of an equimolar dose of medium‐chain triglycerides significantly accelerated small‐bowel transit time (59 ± 6 minutes) compared with long‐chain triglycerides and control (p<.05). In six individuals, small‐bowel transit time was shorter during the administration of medium‐chain triglycerides compared with control, and three of these subjects experienced abdominal symptoms. Plasma cholecystokinin levels increased significantly (p<.05) during the administration of long‐chain triglycerides, from 2.6 ± 0.3 pmol/L to a maximum of 4.3 ± 0.6 pmol/L. No significant alterations were observed in plasma cholecystokinin levels during administration of medium‐chain triglycerides or in the control experiment.Conclusions: Although it significantly increases cholecystokinin secretion, the intraduodenal infusion of long‐chain triglycerides does not affect small‐bowel transit time, whereas the infusion of medium‐chain triglycerides accelerates small‐bowel transit time, independent of cholecystokinin.(Journal of Parenteral and EnteralNutrition19:5–8, 1995)

ISSN:0148-6071    

DOI:10.1177/014860719501900105

出版商:SAGE Publications    

年代:1995

数据来源: WILEY

摘要:

Background:Endotoxemia is characterized by a marked increase in the uptake of amino acids by the liver, but the regulation of this response has not been fully elucidated. In the current study, we investigated the potential role of prostaglandins as mediators of this response. We examined thein vivoeffects of the anti‐inflammatory agent ketorolac, a cyclo‐oxygenase inhibitor that blocks prostaglandin synthesis, on hepatic amino acid transport activity in endotoxin‐treated rats.Methods: We assayed the activities of the Na+‐dependent transport systems A and N in hepatic plasma membrane vesicles prepared from endotoxemic rats that were pretreated with ketorolac or vehicle. Hepatic plasma membrane vesicles were prepared by differential centrifugation, and the transport of [3H]glutamine (system N) and [3H]2‐methylamino‐isobutyric acid (system A) was assayed. Hepatic plasma membrane vesicles were also prepared from normal rats that received prostaglandin E2, and glutamine and MeAIB transport were measured.Results: Endotoxin treatment resulted in a twofold to threefold increase in Na+‐dependent amino acid transport activity in hepatic plasma membrane vesicles secondary to an increase in the transport Vmax, which was consistent with the appearance of increased numbers of corresponding transporter proteins in the hepatocyte plasma membrane. Pretreatment with ketorolac almost completely abrogated the endotoxin‐induced increase in hepatic amino acid transport. Administration of prostaglandin E2to normal rats resulted in a statistically significant increase in glutamine and alanine transport by hepatic plasma membrane vesicles prepared from these animals. Conclusions: Prostaglandins play a key role in mediating the accelerated hepatic amino acid transport that occurs during endotoxemia.(Journal of Parenteral and Enteral Nutrition19:9–14, 1995)

ISSN:0148-6071    

DOI:10.1177/014860719501900109

出版商:SAGE Publications    

年代:1995

数据来源: WILEY

ISSN:0148-6071    

DOI:10.1177/0148607195019001011

出版商:SAGE Publications    

年代:1995

数据来源: WILEY

摘要:

Background:Loss of lean‐body mass has been found to be predictive of death from wasting in HIV‐infected individuals. Several clinically applicable, noninvasive methods for estimating body wasting are available, but the comparability of these methods is not known. The objective of this study was to assess the agreement between estimates of lean‐body mass in HIV‐infected men.Methods: Lean‐body mass was measured by bioelectrical impedance assessment, by prediction equations that used anthropometric measurements, and by total body electrical conductivity as the comparison method in 27 outpatient HIV‐infected men seen at the Houston Veterans Affairs Special Medicine Clinic. Agreement was assessed by comparing the difference between two methods (the bias) with the mean of those two methods. This statistical approach evaluates whether two methods are similar enough that measurements from one might accurately replace those of the other.Results: The mean ± SE for lean‐body mass were 55.98 ± 1.96 kg for total body electrical conductivity and 55.18 ± 1.27 kg for bioelectrical impedance assessment; they ranged from 55.18 ± 1.27 to 63.71 ± 1.89 kg for the prediction equations. Conclusions: In individual subjects, no alternate method gave estimates of lean‐body mass that were the same as estimates from total body electrical conductivity. One prediction equation (Brozek) gave estimates that might be useful for following changes in fat‐free mass over time because the bias did not change substantially for increasing values of lean‐body mass. On the other hand, because there were no statistically significant differences between the mean lean‐body mass estimates by total body electrical conductivity and those measured by bioelectrical impedance assessment or a prediction equation on the basis of body mass index, the latter two methods might be useful in assessing lean‐body mass in groups. (Journal of Parenteral and Enteral Nutrition19:28–32, 1995)

ISSN:0148-6071    

DOI:10.1177/014860719501900128

出版商:SAGE Publications    

年代:1995

数据来源: WILEY

摘要:

Background: This study was undertaken to determine the effect of chemically defined structured lipids on nonspecific host defense and on histologic patterns of liver and lungs compared with a physical mixture of long‐chain triglycerides and medium‐chain triglycerides in a continuous low‐dose endotoxin rat model.Methods:Forty male Sprague‐Dawley rats, divided into four feeding groups (structured lipids, structured lipids + endotoxin, physical mixture, physical mixture + endotoxin), received total parenteral nutrition for 48 hours. During the first part of the study, 24 animals were given an injection of liveEscherichiacoli labeled with radioactive iron (59Fe) to investigate the function of the reticuloendothelial system. During the second part of the study, the liver and lungs of 16 animals were histologically examined using light and electron microscopy.Results:Despite the similar values in the control groups, the animals receiving structured lipids + endotoxin sequestered a significantly greater percentage of bacteria in the liver and spleen (p≤.01) and a significantly lesser percentage in the lung (p≤.05) compared with the animals given physical mixture + endotoxin as part of their diet. Moreover, rats in the physical mixture + endotoxin group showed a microscopically evaluated higher fatty infiltration in the liver than did the structured lipids + endotoxin group.Conclusions: The results of this study indicate that chemically defined structured lipids reduce fatty infiltration of the liver compared with a physical mixture of the same compounds in an animal model of metabolic stress. They were accompanied by a better function of the reticuloendothelial system and a lesser bacterial sequestration in the lungs. (Journal of Parenteral and Enteral Nutrition19:33–40, 1995)

ISSN:0148-6071    

DOI:10.1177/014860719501900133

出版商:SAGE Publications    

年代:1995

数据来源: WILEY

摘要:

Background: Earlier clinical studies have demonstrated improved nitrogen balance in nonstressed patients receiving hypocaloric feedings and growth hormone (GH). This study investigates the effect of GH on nitrogen balance, on serum protein concentrations, and on other indices of nutrition when combined with enteral feeding in immobilized patients after closed‐head injury or spinal cord injury.Methods: Sixteen patients who tolerated enteral feedings and remained nonseptic were randomized to receive either placebo or 0.2 mg/kg recombinant human GH for 7 to 13 days. Nitrogen balances were collected daily, and serum proteins were measured at study entrance and exit.Results: GH treatment resulted in higher GH and insulin‐like growth factor‐1 concentrations but did not improve nitrogen balance. GH treatment also resulted in increased transferrin and serum albumin levels and total lymphocyte count during the study period.Conclusions:Adjuvant recombinant human GH has no effect on nitrogen balance in highly stressed, totally immobilized patients after head or spinal cord injury, but it significantly enhances constitutive serum protein concentrations and other indices of nutritional repletion.(Journal of Parenteral and Enteral Nutrition19:41–46, 1995)

ISSN:0148-6071    

DOI:10.1177/014860719501900141

出版商:SAGE Publications    

年代:1995

数据来源: WILEY

摘要:

Background:This study reports the effects of ingesting branched‐chain amino acids (leucine, valine, and isoleucine) on protein metabolism in four men.Methods:To calculate leg protein synthesis and breakdown, we used a new model that utilized the infusion of L‐[ring‐13C6]phenylalanine and the sampling of the leg arterial‐venous difference and muscle biopsies. In addition, protein‐bound enrichments provided for the direct calculation of muscle fractional synthetic rate. Four control subjects ingested an equivalent amount of essential amino acids (threonine, methionine, and histidine) to discern the effects of branched‐chain amino acid nitrogen vs the effects of essential amino acid nitrogen. Each drink also included 50 g of carbohydrate.Results:Consumption of the branched‐chain and the essential amino acid solutions produced significant threefold and fourfold elevations in their respective arterial concentrations. Protein synthesis and breakdown were unaffected by branched‐chain amino acids, but they increased by 43% (p<.05) and 36% (p<.03), respectively, in the group consuming the essential amino acids. However, net leg balance of phenylalanine was unchanged by either drink. Direct measurement of protein synthesis by tracer incorporation into muscle protein (fractional synthetic rate) revealed no changes within or between drinks. Whole‐body phenylalanine flux was significantly suppressed by each solution but to a greater extent by the branched‐chain amino acids (15% and 20%, respectively) (p<.001).Conclusions:These results suggest that branched‐chain amino acid ingestion suppresses whole‐body proteolysis in tissues other than skeletal muscle in normal men.(Journal of Parenteral and Enteral Nutrition19:47–54, 1995)

ISSN:0148-6071    

DOI:10.1177/014860719501900147

出版商:SAGE Publications    

年代:1995

数据来源: WILEY

摘要:

Background:Although frequently done, estimating the energy requirements of individual burn patients without measuring their resting metabolic rate is a less than satisfactory method of evaluation.Methods:We tested whether heart rate, which relates to the energy expenditure during physical activity, is also associated with postburn hypermetabolism (calculated as percentage increase of resting metabolic rate above the predicted normal fasting resting metabolic rate). Twenty‐three patients [12 men and 11 women, aged 38 ± 13 years (mean ± SD); weight, 71.6 ± 14.8 kg; body mass index, 25.4 ± 3.6; total burn surface area, 35.3 ± 17.8% (percentage of body surface)] were studied weekly for 3 weeks after an overnight fast.Results:Measured resting metabolic rates and heart rates were 2016 ± 497 kcal/d, 101 ± 13 bpm (n = 19); 2231 ± 485 kcal/d, 107 ± 13 bpm (n = 18); and 1903 ± 598 kcal/d, 99 ± 14 bpm (n = 11) for weeks 1, 2, and 3, respectively. Postburn hypermetabolism was +36% ± 19%, +55% ± 27%, and +36% ± 35% in the first, second, and third week, respectively. In each week postburn hypermetabolism correlated with heart rate(r =0.65,p=.003;r =0.69,p=.001; andr= 0.80,p=.002, respectively). Only in the second week did postburn hypermetabolism correlate with total burn surface area (r = 0.52,p=.02); there was no correlation with body temperature. In a multiple regression analysis, predicted resting metabolic rate, heart rate, and total burn surface area together explained 77% of all of the variance observed in the 48 fasting resting metabolic rates that were measured in the study(r2= 0.77,p<.0001), and each of these variables also had a significant partial correlation with fasting resting metabolic rates(r2=0.45,p<.0001;r2= 0.29,p<.0001; andr2= 0.03,p<.03, respectively).Conclusions:In burn patients, variability in heart rate is associated with a significant part of postburn hypermetabolism variability. Therefore, heart rate may be considered a useful variable to be used for the evaluation of the energy requirements of severely burned patients.(Journal of Parenteral and Enteral Nutrition19:55–62, 1995)

ISSN:0148-6071    

DOI:10.1177/014860719501900155

出版商:SAGE Publications    

年代:1995

数据来源: WILEY