摘要:

Background:It is known that tumor progression is associated with a depletion in host glutamine (Gln) stores and a depression of natural killer (NK) cell activity. After demonstrating an in vitro dependence of NK cell activity on Gln and glutathione concentration, this study evaluated the effects of oral Gln on Gln and glutathione metabolism, NK cell activity, and tumor growth in the tumor‐bearing rat.Methods:Two days before tumor implantation, rats (n = 32) were randomized to receive Gln (1 g/kg/d) or an isonitrogenous amount of glycine by gavage and pair‐fed food. On day 21 after tumor implantation, rats were killed, and tumors were measured and processed for glutaminase activity, glutathione content, and tumor morphometrics. Splenic lymphocytes were assayed for NK cell activity via a chromium (51Cr) release assay using YAC (NK‐cell‐sensitive mouse tumor cell line) target cells. Blood Gln and glutathione were measured. A second set of rats (n = 16) were treated similarly except that ketamine was given twice weekly to suppress NK cell activity.Results:During the 3‐week study period, tumor growth was decreased by 40% in the Gln group. This decrease in growth was associated with a 30% increase in NK cell activity. Administration of ketamine to rats completely reversed the higher NK cell activity and decreased the tumor growth seen in the Gln‐treated group.Conclusions:These data indicate that oral Gln supplementation, through support of host Gln stores and glutathione production, may decrease tumor growth by enhancing NK cell activity. (Journal of Parenteral and Enteral Nutrition18:471–476, 1994)

ISSN:0148-6071    

DOI:10.1177/0148607194018006471

出版商:SAGE Publications    

年代:1994

数据来源: WILEY

摘要:

Background:A rat model of acute renal failure (ARF) with sepsis (ARF+S) was developed to simulate the clinical syndrome of hypercatabolic illness in patients with ARF.Methods:Sepsis was created by ligation and needle puncture of the cecum; ARF was created by left renal artery clamping and contralateral nephrectomy.Results:Two studies were performed. In study 1, rats with sham surgery, sepsis, ARF, and ARF+S were examined for 48 hours. During the first 24 hours after surgery, ARF and ARF+S rats displayed increased urea and ammonia nitrogen appearances and abnormal plasma amino acid levels. These abnormalities were exaggerated in ARF+S rats. In study 2, sham, ARF, and ARF+S rats were injected with sodium bicarbonate or normal saline. During the first 24 hours after surgery, the ARF and ARF+S rats showed an increase in urea nitrogen appearance to 210% and 293%, respectively, of sham values, which was greater than the levels that have been previously reported. Sodium bicarbonate treatment did not influence nitrogen output.Conclusions:Rats with ARF+S may be a useful model for studying catabolic patients with ARF. The lack of effect of sodium bicarbonate on nitrogen balance merits additional study. (Journal of Parenteral and Enteral Nutrition18:477–485, 1994)

ISSN:0148-6071    

DOI:10.1177/0148607194018006477

出版商:SAGE Publications    

年代:1994

数据来源: WILEY

摘要:

Background:Gastrointestinal side effects, particularly diarrhea, are still the main reasons for discontinuation of enteral nutrition. Although the causes of diarrhea are diverse, the enteral nutrition solution is frequently suspected of playing a leading role in causing diarrhea.Methods:Our randomized, prospective, double‐blind trial with 100 patients assessed the effects of feeding a standard diet (Nutrodrip Standard)vsthe same diet supplemented with 20 g of soluble fiber, containing partially hydrolyzed guar gum (Sunfiber), per 1000 mL. Thirty patients received total enteral nutrition postoperatively, and 70 patients received enteral supplementation.Results:The patients receiving total enteral nutrition with soluble fiber had decreased diarrhea but increased flatulence. In none of these patients did enteral feeding have to be discontinued because of gastrointestinal side effects, whereas in four patients who were on a standard diet, enteral feeding had to be interrupted because of diarrhea (p<.05). Similar observations were made in patients receiving enteral supplementation. In both groups, the incidence of diarrhea decreased significantly with the soluble fiber diet compared with the standard diet (6vs15,p<.05).Conclusions:Enteral feeding with a formula supplemented with partially hydrolyzed guar gum reduces the incidence of diarrhea in patients receiving total enteral nutrition as well as in those receiving enteral supplementation, regardless of the cause of diarrhea. The increased hydrogen production and the significantly higher rate of flatulence are likely to result from fermentation of the soluble fiber in the colon, with concomitant production of short‐chain fatty acids, which leads to increased absorption of short‐chain fatty acids, sodium, and water by the colonocytes. This effect, together with the observed cholecystokinin‐mediated decrease in colonic transit time with partially hydrolyzed guar gum, may explain the reduction in the incidence of diarrhea in this study. (Journal of Parenteral and Enteral Nutrition18:486–490, 1994)

ISSN:0148-6071    

DOI:10.1177/0148607194018006486

出版商:SAGE Publications    

年代:1994

数据来源: WILEY

摘要:

Using a transplantable Yoshida sarcoma in a rat model of total parenteral nutrition (TPN), we measured the effectiveness of an arginine‐enriched amino acid solution (AI‐82) on muscle glutamine concentration and muscle protein synthesis compared with that of a conventional amino acid solution (Proteaminl2). After tumor‐bearing rats had been given one of two isocaloric TPN regimens for 6 days, [15N]glycine (99 atom %) containing TPN solution was infused into animals at a constant rate of 8 mg of [15N]glycine per hour for 18 hours, after which the liver, skeletal muscle (gastrocnemius muscle), and tumor protein synthesis rates were measured. A significantly increased whole muscle protein synthesis rate was observed in the AI‐82 group; there was no difference in the whole liver and tumor protein synthesis rates between the two groups. When each TPN solution was administered for 1 week, muscle concentrations of arginine, ornithine, glutamine, and glutamate were considerably higher in the AI‐82 group than in the Proteamin12 group, and these differences were also accompanied by a decrease in the plasma branched‐chain amino acid (BCAA) (leucine, isoleucine, and valine) levels in the AI‐82 group. The high levels of muscle glutamine concentration in the AI‐82 group were investigated in connection with the high use of exogenous branched‐chain amino acids. (Journal of Parenteral and Enteral Nutrition18:491–496, 1994)

ISSN:0148-6071    

DOI:10.1177/0148607194018006491

出版商:SAGE Publications    

年代:1994

数据来源: WILEY

摘要:

Seven children with cystic fibrosis (aged 7 to 12 years) were studied in the fasted and fed states. Using a primed, constant, intravenous infusion of NaH13CO3, the rate of appearance of CO2(RaCO2) was estimated. Net CO2excretion (VCO2) was also measured. Energy expenditure was calculated using the food quotient. RaCO2(mean ± SD) (μmol·kg−1·min−1) in the fasted and fed states (297 ± 59 and 359 ± 67) was 117% and 105% of VCO2(259 ±48 and 352 ± 72). Feeding induced a 23% and a 37% increase in RaCO2and VCO2, respectively, and respective 19% and 33% increases in energy expenditure (p<.05). Measurement of CO2production by isotopic dilution is a useful index of group changes in energy expenditure, including those induced by feeding. (Journal of Parenteral and Enteral Nutrition18:497–502, 1994)

ISSN:0148-6071    

DOI:10.1177/0148607194018006497

出版商:SAGE Publications    

年代:1994

数据来源: WILEY

摘要:

Background:The pathophysiologic mechanisms behind the development of liver steatosis during total parenteral nutrition (TPN) and the possible relationship to alterations of lipoprotein lipase activities in different tissues are not fully known. It is also unknown whether continuous and discontinuous administration of TPN affect lipid metabolism differently.Methods:TPN, including 8.4 g of triglycerides per kilogram per day, was given for 10 days to two groups of male Sprague‐Dawley rats that received the infusions discontinuously and continuously, respectively. Freely fed rats were used as controls.Results:TPN led to hyperlipidemia and accumulation of triglycerides in the liver. High‐density lipoproteins were enriched in triglycerides, whereas high‐density lipoprotein cholesterol and phospholipid levels were low. The activities of hepatic lipase were markedly decreased, and lipoprotein lipase activities in adipose tissue and in cardiac muscle were both up‐regulated. The increased levels of cholesterol and phospholipids in the serum of TPN animals were more pronounced after discontinuous administration.Conclusions:TPN including lipids interferes with the normal regulation of lipid metabolism. Although the mechanisms remain obscure, the elevation of lipoprotein lipase activities seems functionally important to accommodate the increased input of triglycerides during TPN. Possibly, the observed alterations in lipase activities may be attributed to a state of hypothyroidism. (Journal of Parenteral and Enteral Nutrition18:503–509, 1994)

ISSN:0148-6071    

DOI:10.1177/0148607194018006503

出版商:SAGE Publications    

年代:1994

数据来源: WILEY

摘要:

The effects of aseptic abscesses induced by subcutaneous injections of turpentine (5 mL/kg body weight) on the acute‐phase protein response (α2‐macroglobulin, α2‐M) and on the circulating albumin and total protein concentrations were assessed in young rats that were made malnourished by restricting dietary intake to an extent that either impaired growth (60% of normal intake) or caused weight loss (0% to 45% of normal intake). The measurements were obtained daily during a period of 4 days in malnourished rats that had lost about 25% body weight but had maintained a stable weight thereafter, or in rats that had lost about 12% body weight and were continuing to lose weight at various rates at the time of the turpentine injection. In animals that were injected while they maintained a stable weight after losing about 25% body weight, the α2‐M response was attenuated fourfold to eightfold compared with control animals (the area under the 4‐day α2‐M curve in control rats was 23.3 ± 2.3 g/L/d). In the depleted animals that were injected while they were actively losing weight (∼12.5% weight loss), the attenuation of the α2‐M response was related to the rate of weight loss or to the extent of dietary restriction (area under the 4‐day α2‐M curve ranged from 5.7 ± 1.4 g/L/d in animals receiving 15% restricted diet to 15.6 ± 1.5 g/L/d in animals receiving the 45% restricted diet). The hypoalbuminemic response was similar in different groups, and the change in total protein concentration generally reflected the change in α2‐M response. The results suggest that dietary restriction can attenuate the acute‐phase protein response and that the magnitude of this attenuation depends not only on the extent of depletion but also on the rate with which the depletion is occurring. (Journal of Parenteral and Enteral Nutrition18:510–515, 1994)

ISSN:0148-6071    

DOI:10.1177/0148607194018006510

出版商:SAGE Publications    

年代:1994

数据来源: WILEY

摘要:

Background:Albumin has a role in the complicated process of platelet aggregation. Although it is known that quantitative changes in plasma albumin alter platelet aggregation, less is known about the interaction between qualitative changes in plasma albumin and platelets. One common qualitative change in plasma albumin is nonenzymatic glycosylation, which occurs during states of prolonged hyperglycemia.Methods:Albumin was selectively removed from normal plasma by means of an affinity column. Glycosylated albumin was added to this albumin‐poor plasma, and it was used to study platelet aggregation induced by low concentrations of arachidonic acid. Platelet aggregation was determined by light transmittance.Results:As the concentration of glucose in which albumin was incubated was increased, there was progressive augmentation of platelet aggregation. At a plasma glucose of 150 mg/dL, average light transmittance was 9.4%, and at 200 mg/dL, it was 24.6%. These values were significantly different at apvalue<.01. At glucose levels of 300 mg/dL and 400 mg/dL, mean light transmittance was 40.6% and 74.4%, respectively, and these values were significantly different withpvalues of<.01.Conclusions:Platelet aggregation in response to a relatively low concentration of arachidonic acid is enhanced in the presence of albumin that has been incubated in a medium containing levels of glucose that are higher than would be seen in normal patients but are consistent with those seen in diabetics with less than optimal control. This augmentation of platelet aggregation is statistically significant. (Journal of Parenteral and Enteral Nutrition18:516–520, 1994)

ISSN:0148-6071    

DOI:10.1177/0148607194018006516

出版商:SAGE Publications    

年代:1994

数据来源: WILEY

摘要:

Background: The metabolic rate of patients suffering severe head trauma (HT) is not well defined, and large variations of resting energy expenditure (REE) have been reported, suggesting an important nonuniformity of REE distribution in HT patients. The purpose of this clinical study was to assess the metabolic rate in mechanically ventilated patients suffering from severe isolated HT, or HT associated with other injuries, in the absence of gross motor activity.Methods:Eighty HT patients undergoing mechanical ventilation were studied between 48 and 72 hours after injury. Three groups of patients were studied in the following clinical settings: (group A) isolated HT, not receiving morphine(n= 34); (group B) isolated HT, receiving an intravenous perfusion of morphine (n = 26) to control gross motor activity; and (group C) HT associated with other serious injuries, receiving intravenous morphine (n = 20) to induce sedation and analgesia. REE was measured with the open‐Douglas‐bag method. Results: No significant differences among the three groups were found in the metabolic rate expressed as the percentage of measured REE from predicted REE and REE expressed in terms of body weight. The mean percent measured REE was 123 ± 16, and REE expressed in terms of body weight was 30 ± 5 kcal/kg per day. Severe hypermetabolism was diagnosed if mean percent measured REE was greater than 130 and was present in 25 of 80 (31%) patients. Conclusions: Severe HT treated with or without morphine was characterized by a moderate state of hypermetabolism after the first days of trauma, but an important proportion of HT patients showed considerably elevated metabolic rates. (Journal of Parenteral and Enteral Nutrition18:521–524, 1994)

ISSN:0148-6071    

DOI:10.1177/0148607194018006521

出版商:SAGE Publications    

年代:1994

数据来源: WILEY

摘要:

The validity of four indicators to predict successful duodenal feeding tube placement was evaluated in a prospective trial. Data were collected on each indicator at prepyloric (≤ 65 cm) and postpyloric (≥ 75 cm) feeding tube lengths. Feeding tubes were placed in 106 patients. Eighteen feeding tubes were located in the stomach, and 88 were in the duodenum. Auscultation (progression of loudest sound locations from the left to the right abdomen) had a positive predictive value of 85% (negative predictive value, 31%). The vacuum effect (a change from 40 mL of aspirated air to ≤ 10 mL after 60 mL of air instillation) had a positive predictive value of 86% (negative predictive value, 45%) and was significantly correlated with duodenal placement (p=.02). Aspirate was present at prepyloric and postpyloric lengths in 35 cases. Ten of these 35 cases had the defined change in pH from ≤ 4.0 to ≥ 6.0 (positive predictive value, 100%; negative predictive value, 28%). The positive predictive value of color (a change to yellow) was also 100% (n = 11); the negative predictive value was 29%. The low negative predictive values of the indicators suggest that the absence of defined changes is of no assistance in discriminating between stomach and duodenal placement. A positive auscultation or vacuum effect test is not conclusive for duodenal placement. A positive pH or color change test may obviate the need for a confirmatory radiograph. However, because 40% of the positive pH‐test feeding tubes and 36% of the positive color‐test feeding tubes were located in the proximal duodenum, we believe refinement of placement techniques and further studies are warranted before elimination of the radiograph is recommended when the pH or color change occurs. (Journal of Parenteral and Enteral Nutrition18:525–530, 1994)

ISSN:0148-6071    

DOI:10.1177/0148607194018006525

出版商:SAGE Publications    

年代:1994

数据来源: WILEY