摘要:

Obesity is a major health problem in the United States today. Traditionally, management of obese hospitalized patients has not differed from that of normal‐weight patients, with calorie and protein needs based on current body weight and weight loss postponed until the acute illness has subsided. This study was undertaken to determine whether obese hospitalized patients (>130% ideal body weight) requiring total parenteral nutrition and given hypocaloric (HC) feedings with adequate protein intake could achieve nitrogen balance comparable with that of controls (C) given isonitrogenous normocaloric formulas. Sixteen obese patients (HC = 9, C = 7) were randomized to either HC (50% resting metabolic energy expenditure, plus protein; calories:nitrogen = 75:1) or C (100% resting metabolic energy expenditure, plus protein; calories:nitrogen = 150:1) formulas. Resting metabolic energy expenditure was determined by indirect calorimetry on day 0 and weekly, and nitrogen balance was determined daily. The two groups were similar in Harris‐Benedict predicted energy expenditure and metabolic energy expenditure, initial and final serum albumin, total iron‐binding capacity, and weight loss. Total daily calorie and nonprotein calorie intake per kilogram body weight were 14 ± 4.1 (HC)vs25 ± 4 (C) and 7 ± 1.9 (HC) vs 20 ± 3 (C), respectively. Protein intake was 1.23 ± 0.4 (HC)vs1.31 ± 0.2 (C) g/kg per day. Initial respiratory quotients were similar and consistent with fasting (HC = 0.7 ± 0.09vsC = 0.66 ± 0.09); final respiratory quotients in C patients reflected mixed fuel use (C = 0.82 ± 0.11vsHC = 0.7 ± 0.12). Mean net nitrogen balance was similar (HC = 1.3 ± 3.6 g of nitrogen per day compared with C = 2.8 ± 6.9 g/d). Eight of nine HC patients achieved positive nitrogen balance as did six of seven C patients. Duration of treatment averaged 9.6 ± 3.0 days. These data indicate that HC feedings can be effectively administered to mildly‐to‐moderately stressed hospitalized obese patients and can achieve nitrogen balance comparable with that of patients given conventional total parenteral nutrition formulas. (Journalof Parenteral and Enteral Nutrition 18:203–207, 1994)

ISSN:0148-6071    

DOI:10.1177/0148607194018003203

出版商:SAGE Publications    

年代:1994

数据来源: WILEY

摘要:

Diets containing either triacetin (the water‐soluble triglyceride of acetate) or long‐chain triglycerides (LCTs) were fed to rats to determine the effects on intestinal mucosa cells and plasma substrates. Male Sprague‐Dawley rats were fed one of three diets, a control diet containing 5% of energy as LCTs or one of two experimental diets that contained 30% of energy as lipid. The lipid component of the two experimental diets was either 100% LCTs or 95% triacetin/5% LCTs. Plasma lactate, glucose, and total ketone body concentrations were not significantly different among dietary treatment groups. Compared with animals fed LCTs and control diet, plasma pyruvate and free fatty acid concentrations were decreased in animals fed triacetin. In contrast, plasma triglyceride concentrations were elevated in animals fed triacetin compared with other groups. Intestinal biochemical measures included total DNA, RNA, protein, and the protein:DNA ratio. Histologic indices measured were villus height in the jejunum and crypt depth in the colon. No significant difference in mucosal protein concentration was observed in the jejunum and colon. Jejunal RNA was significantly decreased in animals fed triacetin compared with other diets. Triacetin feeding significantly increased the DNA content in the jejunum and colon (thereby lowering the protein:DNA ratio), indicating smaller, more numerous cells. Jejunal villus height and colonic crypt depth were not significantly different among dietary treatment groups. Provision of a balanced diet containing 28.5% of the total calories as triacetin had no adverse effects on metabolic substrates and resulted in smaller and more numerous mucosal cells in the jejunum and colon. These data indicate that the short‐chain triglyceride triacetin could aid in the maintenance of gut integrity and in the treatment of certain intestinal disorders. (Journalof Parenteral and Enteral Nutrition18:208–213, 1994)

ISSN:0148-6071    

DOI:10.1177/0148607194018003208

出版商:SAGE Publications    

年代:1994

数据来源: WILEY

摘要:

The present study evaluates the effect of insulin and amino acids on nitrogen balance in the immediate postoperative period in moderately stressed patients who have undergone major abdominal surgical operations. Patients were randomly assigned into two large groups (n = 16 each) and four subgroups (n = 8 each). Groups ICONand IINSreceived an infusion of total parenteral nutrition solution containing 0.25 g of nitrogen per kilogram per day with a calorie:nitrogen (C:N) ratio of 150:1. Groups IICONand IIINSreceived twice the load of nitrogen with a C:N ratio of 75:1. Groups IINSand IIINSreceived an additional continuous infusion of insulin at a rate of 1.0 mU/kg per minute for 7 days. During the total parenteral nutrition period, the patients were kept NPO, and 24‐hour urine output was collected for estimation of total nitrogen excretion and nitrogen balance. Net nitrogen excretion (grams per kilogram per day) averaged 0.143 ± 0.06 in IINSand 0.23 ± 0.08 in ICON(p<.05) and 0.178 ± 0.6 in IIINSand 0.25 ± 0.10 in IICON(p<.05). Nitrogen balance (grams per day) was positive in the four groups: +0.65 ± 3.8 in IINSand + 6.74 ± 2.94 in ICON(p<.05), and +14.4 ± 2.61 in IIINSand + 11.63 ± 6.44 in IICON(p= not significant). The average nitrogen incorporation (percent per day) was: 41.3 ± 6.2 in IINSand 14.6 ± 20.1 in ICON(p<.05), and 58.3 ± 4.5 in IIINS and 38.7 ± 26.2 in IICON(p= not significant). The results indicate that nitrogen balance in modestly stressed subjects is achieved at nitrogen intakes of approximately 0.25 g/kg and a C:N ratio of 150:1. Doubling the nitrogen intake while decreasing the C:N ratio of 75:1 resulted in higher positive nitrogen balance. Insulin infusion, to achieve physiologic elevation in plasma insulin (55 to 70 μU/mL), resulted in further improvement in positive nitrogen balance in the group receiving lower nitrogen intake, suggesting that the effect of amino acids in improving nitrogen accretion is saturable. (Journal of Parenteral and Enteral Nutrition18:214–218, 1994)

ISSN:0148-6071    

DOI:10.1177/0148607194018003214

出版商:SAGE Publications    

年代:1994

数据来源: WILEY

摘要:

Parenteral nutrients can be used to manipulate cell proliferation after partial hepatectomy. The relationship among macronutrients—glucose, monoacetoacetin, amino acids— and liver regeneration after partial hepatectomy was investigated. Male rats were anesthetized, received a 70% hepatectomy, and received a low‐dose infusion of (1) glucose or (2) monoacetoacetin and a high‐dose infusion of (3) glucose, (4) glycerol‐glucose, or (5) monoacetoacetin‐glucose beginning 6 hours after surgery. The five nonprotein nutrient combinations were infused with and without amino acids. Rats were killed 48 hours after partial hepatectomy, and the label and mitotic indices were determined. Each of the five treatments had a higher label index with amino acids present than with amino acids absent. Low‐dose glucose and monoacetoacetin as well as high‐dose glucose and glucose‐glycerol had higher mitotic indices with amino acids than without amino acids. High‐dose monoacetoacetin‐glucose was associated with a greater mitotic index than was any other nonprotein substrate treatment, and this response was independent of amino acids being present or absent. In summary, (1) amino acids were needed for maximal cell proliferation rate; (2) the absence of amino acids and not the presence of glucose resulted in reduction of the label and mitotic indices for regenerating liver; (3) high‐dose monoacetoacetin increased mitosis with or without amino acids; and (4) monoacetoacetin activity was dose dependent. The results indicate that the best nutrient for treatment of patients with liver injury is acetoacetate. The second best nutrient would be the combination of high‐dose glucose and amino acids. The results further indicate that glucose should not be administered to patients with liver injury unless accompanied by amino acids. (Journal of Parenteral and Enteral Nutrition18:219–224, 1994)

ISSN:0148-6071    

DOI:10.1177/0148607194018003219

出版商:SAGE Publications    

年代:1994

数据来源: WILEY

摘要:

Dodecanedioic acid (C12), a saturated, aliphatic dicarboxylic acid with 12 carbon atoms, was given as an intravenous bolus (800 μmol/kg of body weight [kgBW]) in male Wistar rats to study its pharmacokinetic profile. Because total plasma C12, which results from the sum of both free and albumin binding fractions, was measured by high‐performance liquid chromatography, an in vitro experimental session was carried out to determine the binding curve of C12 in rat plasma. These data were then used to calculate the plasma C12 free fraction in invivoexperiments. The best fit obtained for the experimental data of albumin binding was obtained with the equation of reversible, saturable binding to one, two, or three classes of noninteracting equivalent sites. Only a single binding site was clearly identified with a dissociation constant of 147 μmol/L and a maximal predicted binding of 1.57 mol/mol albumin. The urinary excretion of C12 was 3.90 ± 1.62% of the administered dose. The pharmacokinetic analysis was performed by one‐compartment model with linear transfer to the tissues, taking into account simultaneously both plasma concentration and urine excretion data. The apparent volume of distribution of C12 was 0.248 ± 0.035 L/kgBW, the apparent first order rate constant to the tissues was 0.0535 ± 0.0123 min−1and that from plasma to urine was 0.00206 ± 0.00051 min−1. The C12 plasma half‐life was 12.47 minutes. Renal clearance was 0.00051 L/kgBWper minute, whereas the systemic clearance was 0.0138 L/kgBWper minute. Because the renal clearance was much less than the rat inulin clearance reported in literature, the presence of C12 passive back‐diffusion was hypothesized. (Journal of Parenteral and Enteral Nutrition18:225–230, 1994)

ISSN:0148-6071    

DOI:10.1177/0148607194018003225

出版商:SAGE Publications    

年代:1994

数据来源: WILEY

摘要:

Selenium deficiency has been reported previously in patients receiving long‐term total parenteral nutrition (TPN) without selenium supplementation in their solutions. The recommended dietary allowance for selenium is 0.87 μg/kg, of which 80% is absorbed. We studied 28 adult long‐term TPN patients aged 21 to 79 years (mean, 51.2 ± 3.0 years) who have received TPN for 8.3 ± 4.4 years. They receive 40 to 60 μg of selenium daily in their TPN solution. Twenty‐one (75%) of 28 patients had low serum selenium levels. Of the patients with low serum selenium levels, 15 (73%) had elevated urinary selenium losses. However, no significant correlation between serum or urine selenium levels and glomerular filtration rate (measured by indium‐111‐diethylenetriamine pentaacetic acid clearance) or renal tubular function was observed. We conclude that the previously described renal homeostatic mechanism for selenium conservation may be significantly impaired in patients receiving long‐term TPN. Such patients may require much larger doses of selenium than previously recommended. Therefore, patients receiving long‐term TPN should have their serum selenium level monitored even though they receive daily selenium supplementation. (Journal of Parenteral and Enteral Nutrition18:231–233, 1994)

ISSN:0148-6071    

DOI:10.1177/0148607194018003231

出版商:SAGE Publications    

年代:1994

数据来源: WILEY

摘要:

The stability of the fat‐soluble vitamins and thiamine, riboflavin, pyridoxine, ascorbate, and folic acid when administered as part of Intralipid 10% was evaluated. Intravenous pediatric vitamin formulations (Vitalipid N Infant and Soluvit Infant) containing the daily dose for term neonates were diluted with Intralipid to final volumes of 12.5 mL or 260 mL. The volumes were then delivered for 24 hours via dihexylethyl‐phtalate‐freein vitroinfusion systems that simulated clinical conditions. The first vitamin‐Intralipid admixture (12.5‐mL volumes) was pumped (by syringe) during 24 hours through neonatal infusion sets placed in an incubator (37 ± 1°C, bilirubin light). Aliquots were collected at the beginning of the experiment and after 24 hours of infusion. The second admixture (260‐mL volumes) was pumped (by a peristaltic pump) through infusion sets during 24 hours and was exposed to periodic indirect sunlight and to continuous fluorescent light to simulate the feeding of a child. Aliquots were collected at 0, 8, and 24 hours during administration of the admixtures. The vitamin concentrations were measured by high‐performance liquid chromatography. The effect of the vitamins on the stability of the emulsion was also assessed by visual inspection, lipid globule size distribution, and pH change. Losses of vitamins vary from different experimental conditions and were for the fat‐soluble vitamins essentially nil, except for phylloquinone, which was 5% to 17% below the initial level. Thiamine, pyridoxine, and folic acid were stable. Losses of riboflavin and ascorbate amounted to 10% to 20% and 9% to 52%, respectively. These results demonstrate that the vitamin stability is good when vitamins are administered in a vitamin‐Intralipid admixture. The addition of vitamins to Intralipid did not alter the stability of the fat emulsion for up to 24 hours at room temperature. (Journalof Parenteral andEnteral Nutrition18:234–239, 1994)

ISSN:0148-6071    

DOI:10.1177/0148607194018003234

出版商:SAGE Publications    

年代:1994

数据来源: WILEY

摘要:

There are multiple reports in the literature of vascular erosion in the innominate vein or superior vena cava from the use of temporary central venous catheters. Catheter malposition is likely to precede the development of superior vena cava perforations, a catastrophic complication of central venous catheters. Catheter malposition after initial adequate placement is a very unusual long‐term complication and delayed recognition of this complication may have disastrous consequences. Should the catheter change position so the tip is angled toward the sidewall, the repetitive movement of the catheter tip that occurs with respiratory excursion and the cardiac cycle may lead to endothelial injury and eventual erosion of the vein. These problems are thought to be alleviated in the patient receiving long‐term intravenous therapy by using a soft Silastic catheter, which may not cause as much damage to the endothelium of the vein. We report three patients with left‐sided long‐term indwelling Silastic catheters that had changed position over time who presented with chest pain upon infusion of their total parenteral nutrition solutions. In each case, chest x‐ray revealed that the tip of the catheter had migrated and was directed against the sidewall of the superior vena cava. In each case, catheter removal and replacement with a new catheter into the right side (subclavian and jugular systems) led to prompt relief of the patient's symptoms. (Jourualof Parenteral and Enteral Nutrition 18:240–242, 1994)

ISSN:0148-6071    

DOI:10.1177/0148607194018003240

出版商:SAGE Publications    

年代:1994

数据来源: WILEY

摘要:

Metabolic acidosis associated with the catabolic state mobilizes muscle nitrogen and releases it into blood as glutamine (GLN) targeted for renal consumption and base generation. Because GLN removed by the kidneys during acidosis is a major drain on the GLN available to other sites, subsequent deprivation may lead to impaired organ function. Conversely, GLN supplementation may spare endogenous supplies and restore organ function. To test this, Sprague‐Dawley rats weighing between 250 and 350 g were pair‐fed elemental diets supplemented with GLN 4.9 g/L (GLN‐ED) or an equivalent mixture of neutral amino acids substituted for GLN (ED). Acid loading was effected by adding hydrochloric acid to the liquid diet (110 mmol/L). Animals were studied in metabolic cages for five consecutive 24‐hour urine collection periods and then anesthetized for short‐term studies of interorgan fluxes and tissue GLN content. Acidosis effected an increase in ammonium nitrogen excretion (fivefold) and a reciprocal decrease (24%) in urea nitrogen excretion. Enteral GLN had no effect on the acidosis‐effected ammonium (2170 ± 71 vs 2059 ± 361 μmol/100 g, EDvsGLN‐ED, respectively) or urea excretion (5522 ± 95vs5915 ± 984 μmol/100 g, EDvsGLN‐ED, respectively). Although arterial blood GLN was not increased in the GLN‐ED group (531 ± 58 vs 438 ± 51 nmol/mL,p=.10), both liver and muscle GLN were elevated (11,650 ± 1137 nmol/gvs7063 ± 578 and 5503 ± 489 and 4742 ± 333 nmol/g, respectively, eachp<.05). GLN released by the hindquarter and liver and removed by the gut was monitored while the rats were under anesthesia by using simultaneously measured blood flow and arteriovenous blood concentration differences. Hindquarter GLN release decreased in the GLN‐ED group compared with the ED group (507 ± 104vs162 ± 148,p<.05). In contrast, gut GLN uptake was markedly increased in the GLN‐ED group (477 ± 153 to 931 ± 228 mmol/min per 100 g,p<.05), whereas hepatic release increased (134 ± 74 to 430 ± 132 nmol/min per 100 g,p<.05). Although splanchnic bed GLN balance registers net uptake, urea excretion was not enhanced with GLN‐ED; rather a large hepatic glutamate efflux appeared (343 ± 150 to 827 ± 240 mmol/min per 100 g,p<.05). Twenty‐four‐hour creatinine excretion increased with GLN‐ED, whereas 3‐methylhistidine excretion decreased (2.46 ± 018 vs 1.86 ± 0.10 μmol/100 g for GLN‐ED and ED, respectively,p<.05). These findings are consonant with enteral GLN supplementation effecting a reduced GLN flow from muscle and sparing proteolysis during chronic metabolic acidosis apparently dependent upon enhanced interorgan flux of the GLN precursor glutamate. (Journal of Parenteral and Enteral Nutrition18:243–247, 1994)

ISSN:0148-6071    

DOI:10.1177/0148607194018003243

出版商:SAGE Publications    

年代:1994

数据来源: WILEY

摘要:

We examined the disposition of a mixed meal by nine conscious dogs fasted for 24 hours with surgical hepatic denervation. The results were compared with those from identical studies carried out previously in 13 hepatic‐innervated dogs. Net gut release of glucose and gluconeogenic precursors (assessed with the arteriovenous difference technique), the resulting blood glucose and plasma insulin concentrations, and the hepatic glucose load were remarkably similar in the two groups. Net hepatic glucose uptake was 4.8 ± 3.6 g in hepatic‐denervated and 7.7 ± 3.3 g in hepatic‐innervated dogs. Cumulative net hepatic lactate release in hepatic‐denervated dogs was 4.3 ± 1.4 g of glucose equivalents, half the value for hepatic‐innervated dogs. Net hepatic carbon intake was similar in the two groups. Hepatic lipogenesis, oxidation, and net glycogen synthesis were qualitatively similar between groups. In conclusion, the disposition of a mixed meal by hepatic‐innervated and hepatic‐denervated dogs was very similar. Subtle alterations in net hepatic balance of substrates (tendencies toward decreases in net hepatic glucose uptake and lactate release) made net carbon retention in denervated livers virtually identical with that in innervated livers. When other compensatory mechanisms are intact, hepatic denervation does not significantly alter hepatic disposition of a mixed meal. (Journal of Parenteral and Enteral Nutrition18:248–255, 1994)

ISSN:0148-6071    

DOI:10.1177/0148607194018003248

出版商:SAGE Publications    

年代:1994

数据来源: WILEY