摘要:

Background:Studies on colon carcinogenesis suggest that the short‐chain fatty acid butyrate may be protective, whereas the secondary bile acid deoxycholate may promote tumor development. Crypt surface hyperproliferation is regarded as a biomarker of colon cancer risk and can be modulated in vitro by the differentiation inducer butyrate and the tumor promoter deoxycholate. We hypothesized that butyrate decreases and deoxycholate increases crypt surface proliferationin vivoand that these effects are mediated by changes in the expression of the protooncogenesc‐Fosandc‐Jun,which are known to regulate proliferation and differentiation. Methods: Twenty‐five adult Sprague‐Dawley rats underwent colonic isolation and 24‐hour intraluminal instillation of 10 mmol/L sodium chloride, 10 mmol/ L sodium butyrate, or 10 mmol/L sodium deoxycholate. Proliferation of the whole crypt and five crypt compartments from base to surface was assessed by proliferating cell nuclear antigen immunohistochemistry. The ϕh value, an index of “premalignant” hyperproliferation, was calculated as the ratio of labeled cells in the two surface compartments divided by the labeled cells in the entire crypt. Expression ofc‐Fosandc‐Junwas evaluated by Western blot.Results:Crypt surface proliferation and the ϕh value were significantly decreased by butyrate and increased by deoxycholate. Butyrate increased colonic expression ofc‐Jun,whereas deoxycholate significantly inducedc‐Fos. Conclusions:Thein vivoeffects on surface proliferation are consistent with a potential tumor‐promoting role for butyrate and a promotive role for deoxycholate in colon carcinogenesis. The concurrently observed effects on colonicc‐Junand c‐Fos expression represent a novel finding and suggest that direct or indirect modulation of protooncogene expression may be the mechanism by which these dietary byproducts regulate proliferationin vivo. (JournalofParenteral and Enteral Nutrition20:243–250, 1996)

ISSN:0148-6071    

DOI:10.1177/0148607196020004243

出版商:SAGE Publications    

年代:1996

数据来源: WILEY

摘要:

Background:Succinic acid dimethyl ester (SAD) is efficiently metabolized in several cell types as pancreatic islet cells, hepatocytes, and colonocytes. The purpose of this study was to assess the overall nutritional value of SAD in the whole organism.Methods:SAD was infused at a rate of 80 μmol/g body weight per day in rats starved for either 2 or 4 days. For comparison, similar experiments were conducted in starved rats receiving an equimolar infusion ofD‐glucose.Results:The ester failed to prevent the starvation‐induced fall in body weight, paraovarian fat mass, and liver or muscle protein content. The infusion of SAD minimized, however, the decrease in plasma glucose and insulin concentrations, liver glycogen content, hepatic glucokinase activity, and islet secretory responsiveness to glucose, otherwise caused by starvation. Likewise, the infusion of SAD delayed the rise in free fatty acid and β‐hydroxybutyrate plasma concentration occurring during starvation. Nevertheless, SAD was less efficient than glucose, infused in an equimolar amount, in preventing the starvation‐induced fall in liver glycogen content, decrease in the pancreatic B‐cell secretory responsiveness to glucose, and stimulation of lipolysis and ketogenesis.Conclusions:SAD displays a significant nutritional value when infused in starved rats. It could thus be used as a tool to prevent the imbalance between ATP generation and use in selected metabolic situations.(Journal of Parenteral and Enteral Nutrition20:251–256, 1996)

ISSN:0148-6071    

DOI:10.1177/0148607196020004251

出版商:SAGE Publications    

年代:1996

数据来源: WILEY

摘要:

Background:Hyperglycemia and an increased ventilatory demand secondary to an increased CO2production are frequent undesirable effects of total parenteral nutrition (TPN) in critically ill patients. This study was performed to assess whether sodium lactate as a metabolic substrate may affect these variables.Methods:Five male patients with multiple trauma during the flow phase were studied during two consecutive 3‐hour periods of isocaloric (1.1 x resting energy expenditure) TPN. Sixty‐five percent of total calories was provided as carbohydrate, 15% as lipids, and 20% as amino acids during the first period (TPN‐glucose), whereas 35% carbohydrate, 30% lactate, 20% lipids, and 15% amino acids (TPN‐lactate) were substituted during the second period. Respiratory gas exchanges and net substrate oxidation were assessed by means of indirect calorimetry. Glucose kinetics was determined by primed‐constant infusion of U‐13C glucose.Results:Compared with TPN‐glucose, TPN‐lactate decreased glycemia by 20%, insulinemia by 43%, net carbohydrate oxidation (assessed from indirect calorimetry) by 34%, and plasma glucose oxidation (assessed from13CO2) by 54%. Respiratory oxygen exchanges were increased by 3.7% due to a 20% thermic effect of lactate, but respiratory CO2exchanges did not change. Pao2decreased by 11.3 mm Hg, indicating that the increased O2consumption was not matched by an appropriate increase in spontaneous ventilation. Arterial pH increased from 7.41 ± 0.04 to 7.46 ± 0.05.Conclusion:Sodium lactate as a metabolic substrate limits hyperglycemia but induces metabolic alkalosis and does not spare the ventilatory demand.(Journal of Parenteral and Enteral Nutrition20:257–263, 1996)

ISSN:0148-6071    

DOI:10.1177/0148607196020004257

出版商:SAGE Publications    

年代:1996

数据来源: WILEY

摘要:

Background:Total parenteral nutrition (TPN) alters both specific and nonspecific immune functions, resulting in immunosuppression. Short‐chain fatty acids have been shown to improve the adaptive responses of the gut after surgery. The following study investigates the effects of adding short‐chain fatty acids to TPN on the immune system after an 80% small bowel resection.Methods:Rats (237 ± 3 g) were infused with either TPN (n = 25) or TPN supplemented with short‐chain fatty acids (n = 26) for 3 or 7 days. Hematologic analysis was performed on peripheral blood and splenocytes were isolated to characterize cell phenotypes, natural killer cell cytotoxicity and to estimate proliferative response. Results: The relative percent of T (CD3+) cells increased (p<.05) and the relative percent of macrophages decreased (p<.001, n = 13) in the spleens of the 3‐day TPN‐fed rats. By day 7, these differences disappeared. The natural killer cells from rats that were supplemented with short‐chain fatty acids had higher (p<.0001) cytotoxic activity than the TPN groups at day 3. Mitogenic response did not differ between groups but were depressed compared with sham‐treated rats. By day 7, rats on standard TPN had larger (p<.0001) spleens than all other groups. This group also had a higher total white blood cell count because of increased numbers of macrophages and neutrophils (p<.02).Conclusion:Short‐chain fatty acids improve components of nonspecific immune responses and may be beneficial in reducing certain aspects of TPNassociated immunosuppression after major surgery.(Journal of Parenteral and Enteral Nutrition20:264–271, 1996)

ISSN:0148-6071    

DOI:10.1177/0148607196020004264

出版商:SAGE Publications    

年代:1996

数据来源: WILEY

摘要:

Background:Parenteral nutrition (PN) is a form of nutrition that can be life‐saving, but its use has inherent risks and it is expensive. Nutrition support teams have been shown to reduce both the rate of complications and excessive use of PN.Methods:Criteria were established to evaluate the appropriateness of PN use in a 487‐bed community teaching hospital. A prospective study of 50 consecutive patients, who received either central or peripheral PN, was conducted.Results:The 50 patients received 469 days of PN. We found that 233 (49.7%) of the 469 days of PN were avoidable. This resulted in the creation of a formal approval process that required prior approval by a physician‐directed multidisciplinary advisory committee before PN could be instituted. The amount of PN subsequently decreased from 500 patient days of PN per month to less than 100.Conclusions:This study supports the idea that inappropriate use of PN can be reduced by physician education plus the continuing oversight of a physician‐directed multidisciplinary advisory group.(Journal of Parenteral and Enteral Nutrition20:272–274, 1996)

ISSN:0148-6071    

DOI:10.1177/0148607196020004272

出版商:SAGE Publications    

年代:1996

数据来源: WILEY

摘要:

Background: It is difficult to predict which patients with a postsurgical short bowel will require long‐term parenteral nutrition. Methods: We performed a retrospective prognostic study for the time to home parenteral nutrition or death from malnutrition (nonautonomy), on the basis of 103 patients with a residual short bowel of 17 to 150 cm. The influence of anatomic variables was summarized through the use of Cox regression model.Results:Of the 103 patients included, 24 lost nutritional autonomy. Three anatomic variables were identified as having independent predictive information; remaining small bowel length (measured on small bowel x‐rays;p=.0001), and jejunoileal anastomosis (p =.01) promoted autonomy, whereas end jejunostomy (p =.002) increased the risk of losing nutritional autonomy.Conclusions:On the basis of these results and on the relative weight of these variables, high‐risk patients for loss of nutritional autonomy were defined as those with jejunoileal anastomosis and a remaining small bowel length<35 cm, patients with jejunocolic anastomosis and remaining small bowel length<60 cm, and patients with an end jejunostomy and remaining small bowel length<115 cm. This classification was thereafter validated on a prospective series of 32 patients.(Journal of Parenteral and Enteral Nutrition20:275–280, 1996)

ISSN:0148-6071    

DOI:10.1177/0148607196020004275

出版商:SAGE Publications    

年代:1996

数据来源: WILEY

摘要:

Background:Glycyl‐glutamine and glycyl‐tyrosine may supply adequate glutamine and tyrosine in amino acid solutions for parenteral nutrition. However, plasma peptides may be transported into the cerebrospinal fluid, exerting effects on the neuronal tissue. Cerebrospinal fluid (CSF) and plasma amino acid concentrations after administration of a glycyl‐glutamine/glycyltyrosine supplemented amino acid solution were therefore evaluated in a randomized controlled comparison with a conventional amino acid infusion.Methods:Dipeptide/amino acid solutions (0.60 mL/h/kg; 82.2 mg total dipeptides/amino acids/h/kg) or conventional amino acid solutions (0.73 mL/h/kg; 83.2 mg total amino acids/h/kg) were infused in 15 patients per group scheduled to undergo spinal anesthesia for urologic surgery over a 12‐hour period preoperatively. Plasma amino acids were measured before the infusion was started. CSF and venous concentrations were analyzed simultaneously before the infusion was stopped. CSF samples were drawn through the spinal needle for anesthesia.Results:The dipeptide‐containing solution did not increase either dipeptide to detectable levels in the CSF (detection limit<5.0 nmol/mL). Venous glycyl‐glutamine increased from below detection limits up to 308 ± 111 nmol/mL (p<.05), whereas glycyl‐tyrosine could not be found. In the dipeptide group, venous glutamine and tyrosine were higher (p<.05) but only tyrosine appeared in small amounts (p<.05) in the cerebrospinal fluid.Conclusions:This study provides no evidence to support a CSF entry of IV glycyl‐tyrosine and glycyl‐glutamine under conditions of a normal blood‐brain barrier in the adult (detection limit 5 nmol/mL). The data suggest that amino acid solutions containing these dipeptides may be used in parenteral solutions for nutrition support.(Journal of ParenteralandEnteral Nutrition20:281–286, 1996)

ISSN:0148-6071    

DOI:10.1177/0148607196020004281

出版商:SAGE Publications    

年代:1996

数据来源: WILEY

摘要:

Background:The purpose of this study was to evaluate the use of selenoprotein P as an indicator of selenium status in patients receiving home parenteral nutrition. Methods: Adult patients (n = 38) who had been on parenteral nutrition with no addition of selenium for 3 to 216 months were included in the study. Plasma samples were analyzed for selenium, selenoprotein P, and extracellular glutathione peroxidase (eGSHPx) using fluorimetry and newly developed radioimmunoassays.Results:The mean plasma (± SD) eGSHPx and selenoprotein P in the patients were 1.9 ± 1.2 mg/L and 0.7 ± 0.4 arbitrary units, respectively, which corresponds to about 50% of the concentration measured in the plasma of the reference subjects (4.0 ± 1.0 mg/L and 1.50 ± 0.17 arbitrary units). The mean plasma selenium concentration was 0.5 ± 0.4 μmol/L, which was approximately half of the concentration measured in the healthy subjects (1.1 ± 0.2 μmol/ L). Thirty‐four (89%) and 20 (53%) patients, respectively, had selenoprotein P and eGSHPx values lower than mean ‐ 2 SD of the reference material. The lowest values observed for selenoprotein P and eGSHPx were 3% and 2% of the reference mean. Selenoprotein P levels correlated significantly to eGSHPx (p = 0.88, p<.0001) and plasma selenium (p = 0.91, p<.0001).Conclusions:The positive correlations between selenoprotein P and eGSHPX and plasma selenium indicates that selenoprotein P may be used as a marker of selenium status in selenium‐depleted patients.(Journal of Parenteral and Enteral Nutrition20:287–291, 1996)

ISSN:0148-6071    

DOI:10.1177/0148607196020004287

出版商:SAGE Publications    

年代:1996

数据来源: WILEY

摘要:

Background:Glutamine is a conditionally essential amino acid for patients with severe catabolic illness, intestinal dysfunction, or immunodeficiency syndromes. Glutamine is a natural component in many enteral preparations, yet lacking methodology hampers its quantitative determination in dietary products.Objective:The present study was assigned to assess glutamine contents in selected enteral products by using a newly developed method enabling the assessment of protein/peptide bound glutamine.Methods:Fourteen commercially available enteral diets (10 protein based and 4 peptide based) were investigated. After removal of interfering fat and carbohydrates, the nitrogen content of the purified preparations was determined by chemiluminescence and protein/peptide bound glutamine was assessed using a three‐step procedure; by using a novel prehydrolysis derivatization technique with bis(1,1‐trifluoroacetoxy)iodobenzene, glutamine is converted to acid stable diaminobutyric acid. The derivatives are hydrolyzed with a new microwave technology, and subsequently the amino acid composition is determined by reversed phase‐high‐performance liquid chromatography after dansyl‐chloride derivatization.Results:The content in the protein‐based preparations varied between 5.2 and 8.1 g/16 g nitrogen. In the peptide‐based products, considerably lower glutamine contents were measured (1.3 to 5.6 g/16 g nitrogen).Conclusion:In the present study, we report for the first time glutamine contents in ready to use enteral products. The daily amount might be satisfactory for healthy individuals but probably not sufficient for the adequate support of the stressed patient. Reliable assessment of glutamine in enteral formulae is a prerequisite to perform clinical studies investigating glutamine requirements in the catabolic state.(Journal of Parenteral and Enteral Nutrition20:292–295, 1996)

ISSN:0148-6071    

DOI:10.1177/0148607196020004292

出版商:SAGE Publications    

年代:1996

数据来源: WILEY

摘要:

Background:The recent Food and Drug Administration Safety Alert recommends in‐line filtration for all total parenteral nutrition admixtures. Although rigid crystalline particulates can be effectively removed by in‐line filters, the fate of flexible lipid droplets (LDs) enlarged through electromechanical destabilization is less clear. Lipid globules>5 μm could lodge in the pulmonary microvasculature and produce an embolic syndrome. Recent evidence suggests that TNAs (Total Nutrient Admixtures) with LDs of 5 μm or more constituting>0.4% of the final fat concentration are unstable.Methods:Six pairs of 1.5‐L TNA dispersions of varying degrees of stability were prepared in duplicate (n = 12) and studied over 30 hours. The number of enlarged fat globules was assessed by laser light extinction for all LDs ≥ 1.75 μm at 0, 6, 24, and 30 hours after preparation. After LD assessments at time 0, admixtures were placed in a temperature‐controlled chamber at 25°C ± 0.1°C. At 6 hours, a simulated patient infusion was begun using a 1.2‐μm filter at a continuous flow rate of 55 mL/h. Pre‐ and postfiltration samples were taken at 6, 24, and 30 hours, equal to times 0, 18, and 24 hours of the simulated infusion. A repeated measure two‐way analysis of variance assessing treatment and time was performed. Dependent variable analyses included number‐weighting of fat globules as>5 μm (LD1), total number ≥ 1.75 μm (LD2), LD1‐LD2 ratio (as %), and volume‐weighted percent of fat (PFAT)>5 μm. Results: In all cases, time was a significant factor and was an expected finding as the stability of all extemporaneously prepared admixtures deteriorates with time. Of the number‐weighted variables, a significant postfiltrate reduction was observed in LD1 (p=.041), LD2 (p<.001), and LD1‐LD2 ratio (p5 μm was significantly reduced by the in‐line filter (p =.029).Conclusions:The TNA1 1.2‐μm filter significantly reduced the total number and concentration of enlarged fat globules. The higher LD1‐LD2 ratio may reflect the effects of filtration on electrically destabilized fat globules. However, total exposure to unstable and very large LDs was significantly reduced, suggesting that in‐line TNA filtration should be a standard part of nutrition therapy.(Journal of ParenteralandEnteral Nutrition20:296–301, 1996)

ISSN:0148-6071    

DOI:10.1177/0148607196020004296

出版商:SAGE Publications    

年代:1996

数据来源: WILEY